Wuhan, China

The Huazhong University of Science and Technology is a public, coeducational research university located in Wuhan, Hubei province, China. As a national key university, HUST is directly affiliated to the Ministry of Education of China. HUST has been referred toas the flagship of China's higher education system after the Chinese Civil War. HUST manages Wuhan National Laboratories for Opto-electronics at Wuchang, which is one of the five national laboratories in China. Wikipedia.


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Zhang Y.,Nanyang Technological University | Niyato D.,Nanyang Technological University | Wang P.,Huazhong University of Science and Technology | Hossain E.,University of Manitoba
IEEE Communications Magazine | Year: 2012

Auction theory, as a subfield of economics, provides useful tools to model, analyze, and optimize radio resource management in cognitive radio environments. By using an auction, radio resources such as subchannel, time slot, and transmit power can be allocated among licensed and unlicensed users in the system, following market laws. Due to the flexibility of mechanism design, there are various auction mechanisms that have been applied to cognitive radio systems with different characteristics. In this article, we first provide an overview of the basics of general auctions. Then the motivations and specific design issues in applying auctions to wireless network architectures and protocols are discussed. Then we review the state of the art in the use of auction theory and mechanism design in cognitive radio networks. This will enable the readers to have a general view of auction fundamentals, as well as the recent development and applications of auction theory in the emerging cognitive wireless networks. © 2012 IEEE.


Patent
Huazhong University of Science and Technology | Date: 2014-06-20

A single-degree-of-freedom magnetic vibration isolation device belongs to vibration isolation devices and solves the following problems: the existing active and passive combined vibration reduction system is complex in structure, needs energy supply, and has low reliability. The present invention includes a metal conductor sleeve, a base, an upper annular permanent magnet, a lower annular permanent magnet, a connecting rod and a center permanent magnet; poles of the upper annular permanent magnet and the lower annular permanent magnet facing to each other have reverse polarity, which are connected to an upper end and a lower end of an inner wall of the metal conductor sleeve respectively; the center permanent magnet is concentrically sleeved on the connecting rod and fixedly connected therewith, and the center permanent magnet is located between the upper annular permanent magnet and the lower annular permanent magnet, and is capable of moving axially together with the connecting rod between the upper annular permanent magnet and the lower annular permanent magnet; and the pole of the center permanent magnet facing to the poles of the upper annular permanent magnet and the lower annular permanent magnet have reverse polarity. The present invention is simple in structure, does not need energy supply, has high reliability, and can generate a static magnetic force and a dynamic magnetic force. Connecting the device according to the present invention with a passive vibration isolation system in parallel can effectively improve the passive vibration isolation performance of the original system.


Patent
Huazhong University of Science and Technology | Date: 2015-06-12

The invention discloses a numerical control (NC) system based on a virtual host computer, the NC system comprising the virtual host computer arranged on a remote server, a local lower computer and a human-machine interactive device for human-machine interaction. The human-machine interactive device is used for providing a human-machine interactive input/output interface. The virtual host computer integrates a human-machine interactive module, a non-real-time/half-real-time task execution unit and a lower-computer control unit, and is used for receiving a NC machining instruction, processing the instruction to form a machine-tool control instruction through the non-real-time/half-real-time task execution unit, and transmitting the control data to the local lower computer through the lower-computer control unit by utilizing a network. The local lower computer controls a machine tool to execute real-time motion control and logic control. The NC system employs a new architecture formed by the upper computer and the lower computer by utilizing virtualization technology, and solves the restriction problems of data processing capability, HMI function expansion and remote machining of a conventional NC system.


Patent
Huazhong University of Science and Technology | Date: 2014-04-02

The present invention discloses an active airbearing device, including a airbearing body, a gas film active adjusting unit, a support body detection unit and a drive control unit, wherein the support body detection device measures a state of airbearing, the drive control system generates a control signal according to a detection signal, drives and controls the gas film active adjusting device to generate an active action, and dynamically adjusts the form of gas films on a airbearing surface, so as to dynamically adjust pressure distribution of gaps between the gas films of the airbearing device, thereby improving dynamic stiffness characteristics of the airbearing. Through the present invention, the dynamic stiffness characteristics of the airbearing can be improved significantly, and the purpose of stabilizing the airbearing is achieved; in addition, the active airbearing device according to the present invention also has the characteristics of a compact structure, convenient operation and control, and high precision, and thus is especially suitable for occasions such as ultra-precision machining or high speed spindle which has high requirements for dynamic stiffness of support.


Patent
Huazhong University of Science and Technology | Date: 2017-02-01

A multi-port DC-DC autotransformer, which is used for realizing interconnected transmission among a plurality of DC systems of different voltage levels. The autotransformer comprises 2N-1 current converters. The 2N-1 current converters are connected in series in sequence at a DC side and are connected to an AC line at an AC side, and the positive electrode of the ith current converter and the negative electrode of the (2N-i)th current converter of the 2N-1 current converters connected in series in sequence are respectively and correspondingly connected to the positive electrode and the negative electrode of the ith DC system, where N is the number of DC systems, and i is the serial number of the current converter. Further disclosed are a capacity design method for the current converters in the autotransformer and a control method for the autotransformer. The autotransformer enables most of the power transmitted among various DC systems to be directly transmitted through the electrical interconnection among the various DC systems without DC-AC-DC conversion, so that the rated voltage and the operating loss of the various current converters are greatly reduced, thereby reducing operating costs.


Patent
Huazhong University of Science and Technology | Date: 2017-01-04

A method for preparing a sericin hydrogel, the method including: 1) weighing a cocoon of a fibroin-deficient mutant silkworm, Bombyx mori, extracting the cocoon by an aqueous solution of LiBr or LiCl, dialyzing an extracted solution to yield a sericin solution having a concentration of a non-degraded sericin of between 0.1 and 4 wt. %; and 2) concentrating the sericin solution to a concentration of between 1.5 and 10 wt. %, adding a crosslinking agent to the concentrated sericin solution at a ratio of between 2 and 500 L of the crosslinking agent per each milliliter of the sericin solution, fully blending the crosslinking agent with the concentrated sericin solution, and keeping a resulting mixture at the temperature of between 4 and 45C for between 5 s and 36 hrs to yield a hydrogel.


Liu H.,Huazhong University of Science and Technology | Won M.-S.,Kunsan National University
Journal of Engineering Mechanics | Year: 2014

A straightforward analytical method is proposed to calculate the reinforcement loads of vertical-reinforced soil composites before the strength of soil is fully mobilized. The method assumes compatibility of soil and reinforcement deformations along the potential failure surface. It makes use of the nonlinear stress-strain relationship of soil in a plane-strain condition and Rowe's stress-dilatancy relationship. It has the advantage of taking into account the soil dilatancy before failure and can properly estimate the reinforcement load with small or medium soil deformation. The effect of soil compaction on the reinforcement load is taken into account through an elastic unloading/reloading approach. The method was first validated against the results of a calibrated numerical analysis. It was then used to predict the reinforcement loads of two large-scale tests. The proposed method has the potential to fully develop into an analytical method for reinforced soil retaining walls, provided that effects of facing restriction and compaction can be quantified.DOI:10.1061/(ASCE)EM.1943-7889.0000686. © 2014 American Society of Civil Engineers.


Liao Y.,China Institute of Technology | Qi H.,Huazhong University of Science and Technology | Li W.,Huawei
IEEE Sensors Journal | Year: 2013

Wireless sensor networks (WSNs) are composed of a large number of inexpensive power-constrained wireless sensor nodes, which detect and monitor physical parameters around them through self-organization. Utilizing clustering algorithms to form a hierarchical network topology is a common method of implementing network management and data aggregation in WSNs. Assuming that the residual energy of nodes follows the random distribution, we propose a load-balanced clustering algorithm for WSNs on the basis of their distance and density distribution, making it essentially different from the previous clustering algorithms. Simulated tests indicate that the new algorithm can build more balanceable clustering structure and enhance the network life cycle. © 2001-2012 IEEE.


Chen S.,Huazhong University of Science and Technology | Du R.,Nanjing Southeast University
Energy | Year: 2011

Turbulent double-diffusive natural convection is of fundamental interest and practical importance. In the present work we investigate systematically the effects of thermal Rayleigh number (Ra), ratio of buoyancy forces (N) and aspect ratio (A) on entropy generation of turbulent double-diffusive natural convection in a rectangle cavity. Several conclusions are obtained: (1) The total entropy generation number (Stotal) increases with Ra, and the relative total entropy generation rates are nearly insensitive to Ra when Ra ≤ 109; (2) Since N > 1, Stotal increases quickly and linearly with N and the relative total entropy generation rate due to diffusive irreversibility becomes the dominant irreversibility; and (3) Stotal increases nearly linearly with A. The relative total entropy generation rate due to diffusive and thermal irreversibilities both are monotonic decreasing functions against A while that due to viscous irreversibility is a monotonic increasing function with A. More important, through the present work we observe a new phenomenon named as " spatial self-copy" in such convectional flow. The " spatial self-copy" phenomenon implies that large-scale regular patterns may emerge through small-scale irregular and stochastic distributions. But it is still an open question required further investigation to reveal the physical meanings hidden behind it. © 2011 Elsevier Ltd.


Wang H.,Huazhong University of Science and Technology
Nucleic Acids Research | Year: 2012

Transcription factors (TFs) are proteins that bind to specific DNA sequences, thereby playing crucial roles in gene-expression regulation through controlling the transcription of genetic information from DNA to RNA. Transcription cofactors and chromatin remodeling factors are also essential in the gene transcriptional regulation. Identifying and annotating all the TFs are primary and crucial steps for illustrating their functions and understanding the transcriptional regulation. In this study, based on manual literature reviews, we collected and curated 72 TF families for animals, which is currently the most complete list of TF families in animals. Then, we systematically characterized all the TFs in 50 animal species and constructed a comprehensive animal TF database, AnimalTFDB. To better serve the community, we provided detailed annotations for each TF, including basic information, gene structure, functional domain, 3D structure hit, Gene Ontology, pathway, protein-protein interaction, paralogs, orthologs, potential TF-binding sites and targets. In addition, we collected and annotated transcription cofactors and chromatin remodeling factors. AnimalTFDB has a user-friendly web interface with multiple browse and search functions, as well as data downloading. It is freely available at http://www.bioguo.org/AnimalTFDB/. © The Author(s) 2011. Published by Oxford University Press.


Pan Q.-K.,Liaocheng University | Wang L.,Tsinghua National Laboratory for Information Sciences and Technology | Gao L.,Huazhong University of Science and Technology | Li W.D.,Coventry University
Information Sciences | Year: 2011

In this paper, an effective hybrid discrete differential evolution (HDDE) algorithm is proposed to minimize the maximum completion time (makespan) for a flow shop scheduling problem with intermediate buffers located between two consecutive machines. Different from traditional differential evolution algorithms, the proposed HDDE algorithm adopted job permutation to represent individuals and applies job-permutation-based mutation and crossover operations to generate new candidate solutions. Moreover, a one-to-one selection scheme with probabilistic jumping is used to determine whether the candidates will become members of the target population in next generation. In addition, an efficient local search algorithm based on both insert and swap neighborhood structures is presented and embedded in the HDDE algorithm to enhance the algorithm's local searching ability. Computational simulations and comparisons based on the well-known benchmark instances are provided. It shows that the proposed HDDE algorithm is not only capable to generate better results than the existing hybrid genetic algorithm and hybrid particle swarm optimization algorithm, but outperforms two recently proposed discrete differential evolution (DDE) algorithms as well. Especially, the HDDE algorithm is able to achieve excellent results for large-scale problems with up to 500 jobs and 20 machines. © 2010 Elsevier Inc. All rights reserved.


Ming T.,Huazhong University of Science and Technology | De Richter R.,National Graduate School of Chemistry, Montpellier | Liu W.,Huazhong University of Science and Technology | Caillol S.,National Graduate School of Chemistry, Montpellier
Renewable and Sustainable Energy Reviews | Year: 2014

The best way to reduce global warming is, without any doubt, cutting down our anthropogenic emissions of greenhouse gases. But the world economy is addict to energy, which is mainly produced by fossil carbon fuels. As economic growth and increasing world population require more and more energy, we cannot stop using fossil fuels quickly, nor in a short term. On the one hand, replacing this addiction with carbon dioxide-free renewable energies, and energy efficiency will be long, expensive and difficult. On the other hand, meanwhile effective solutions are developed (i.e. fusion energy), global warming can be alleviated by other methods. Some geoengineering schemes propose solar radiation management technologies that modify terrestrial albedo or reflect incoming shortwave solar radiation back to space. In this paper we analyze the physical and technical potential of several disrupting technologies that could combat climate change by enhancing outgoing longwave radiation and cooling down the Earth. The technologies proposed are power-generating systems that are able to transfer heat from the Earth surface to the upper layers of the troposphere and then to the space. The economical potential of some of these technologies is analyzed as they can at the same time produce renewable energy, thus reduce and prevent future greenhouse gases emissions, and also present a better societal acceptance comparatively to geoengineering. © 2014 The Authors.


Shi Z.,Huazhong University of Science and Technology | Phillips G.O.,Glyndwr University | Phillips G.O.,Phillips Hydrocolloids Research Ltd | Yang G.,Huazhong University of Science and Technology
Nanoscale | Year: 2013

Cellulose-based electroconductive composites can be prepared by combining conducting electroactive materials with hydrophilic biocompatible cellulose. Inorganic nanoparticles, such as metal ions and oxides, carbon nanotubes, graphene and graphene oxide, conducting polymers, and ionic liquids (through doping, blending or coating) can be introduced into the cellulose matrix. Such composites can form a biocompatible interface for microelectronic devices, and provide a biocompatible matrix or scaffold for electrically stimulated drug release devices, implantable biosensors, and neuronal prostheses. Here the benefits of combining conventional and bacterial cellulose with these electroactive composites are described and future applications are considered. © The Royal Society of Chemistry 2013.


Yang Q.,Huazhong University of Science and Technology | Yang Q.,Peking University | Chen G.Q.,Peking University
Energy Policy | Year: 2012

Nonrenewable energy cost is accounted for the believed renewable biofuel of corn-ethanol in China. By a process-based energy analysis, nonrenewable energy cost in the corn-ethanol production process incorporating agricultural crop production, industrial conversion and wastewater treatment is conservatively estimated as 1.70 times that of the ethanol energy produced, corresponding to a negative energy return in contrast to the positive ones previously reported. Nonrenewable energy cost associated with wastewater treatment usually ignored in previous researches is shown important in the energy balance. Denoting the heavy nonrenewability of the produced corn-ethanol, the calculated nonrenewable energy cost would rise to 3.64 folds when part of the nonrenewable energy cost associated with water consumption, transportation and environmental remediation is included. Due to the coal dominated nonrenewable energy structure in China, corn-ethanol processes in China are mostly a conversion of coal to ethanol. Validations and discussions are also presented to reveal policy implications against corn based ethanol as an alternative energy in long term energy security planning. © 2011 Elsevier Ltd.


Zeng T.,Huazhong University of Science and Technology | Zeng T.,Fiberhome Technologies Group
Optics Express | Year: 2013

We proposed a new method for superchannel transmission based on the newly proposed multi-channel equalization technique. This method allows us to realize tight channel spacing (equal to the baud rate) without using frequency-locked lasers and complex spectral shaping techniques at the transmitter. The inter-channel interference originated from the tight channel spacing is removed at the receiver by joint equalization of multiple adjacent channels. When the channel spacing is equal to the baud rate, our simulation results show that, with conventional oversample ratio (2 samples per symbol), realistic laser frequency offset and laser linewidth, the proposed multi-channel-equalization based method can achieve better performance than the traditional method using spectral shaping plus single channel equalization, although at the expense of a moderate increase in DSP complexity. The paper also gives a simple method to process the data after conventional chromatic dispersion compensation, which enables subsequent multi-channel equalization for long-haul transmissions. © 2013 Optical Society of America.


Shi Z.,Huazhong University of Science and Technology | Zhang Y.,Huazhong University of Science and Technology | Phillips G.O.,Glyndwr University | Phillips G.O.,Phillips Hydrocolloids Research Ltd | Yang G.,Huazhong University of Science and Technology
Food Hydrocolloids | Year: 2014

Bacterial cellulose (BC), a microbial polysaccharide, has significant potential as a food ingredient in view of its high purity, in situ change of flavor and color, and having the ability to form various shapes and textures. As a nano-scale fiber it can form a 3D network structure. Its material properties are multifunctional, with potential uses for thickening and gelling, stabilizing, water-binding and as a packing material. This review deals with current research and possible applications in the food industry. © 2013 Elsevier Ltd.


Yuan L.-X.,Huazhong University of Science and Technology | Wang Z.-H.,Huazhong University of Science and Technology | Zhang W.-X.,Huazhong University of Science and Technology | Hu X.-L.,Huazhong University of Science and Technology | And 3 more authors.
Energy and Environmental Science | Year: 2011

The olivine LiFePO4 now stands as a competitive candidate of cathode material for the next generation of a green and sustainable lithium-ion battery system due to its long life span, abundant resources, low toxicity, and high thermal stability. In this review, we focus on LiFePO4 and discuss its structure, synthesis, electrochemical behavior, mechanism, and the problems encountered in its application. The major goal is to highlight some recent development of LiFePO4 with high rate capability, high energy density, and excellent cyclability resulting from conductive coating, nanocrystallization, or preparation. © 2011 The Royal Society of Chemistry.


Lu X.,Huazhong University of Science and Technology | Naidis G.V.,RAS Joint Institute for High Temperatures | Laroussi M.,Old Dominion University | Ostrikov K.,CSIRO | Ostrikov K.,University of Sydney
Physics Reports | Year: 2014

This review focuses on one of the fundamental phenomena that occur upon application of sufficiently strong electric fields to gases, namely the formation and propagation of ionization waves-streamers. The dynamics of streamers is controlled by strongly nonlinear coupling, in localized streamer tip regions, between enhanced (due to charge separation) electric field and ionization and transport of charged species in the enhanced field. Streamers appear in nature (as initial stages of sparks and lightning, as huge structures-sprites above thunderclouds), and are also found in numerous technological applications of electrical discharges. Here we discuss the fundamental physics of the guided streamer-like structures-plasma bullets which are produced in cold atmospheric-pressure plasma jets. Plasma bullets are guided ionization waves moving in a thin column of a jet of plasma forming gases (e.g.,He or Ar) expanding into ambient air. In contrast to streamers in a free (unbounded) space that propagate in a stochastic manner and often branch, guided ionization waves are repetitive and highly-reproducible and propagate along the same path-the jet axis. This property of guided streamers, in comparison with streamers in a free space, enables many advanced time-resolved experimental studies of ionization waves with nanosecond precision. In particular, experimental studies on manipulation of streamers by external electric fields and streamer interactions are critically examined. This review also introduces the basic theories and recent advances on the experimental and computational studies of guided streamers, in particular related to the propagation dynamics of ionization waves and the various parameters of relevance to plasma streamers. This knowledge is very useful to optimize the efficacy of applications of plasma streamer discharges in various fields ranging from health care and medicine to materials science and nanotechnology. © 2014 Elsevier B.V.


Zhang G.,Southwest Jiaotong University | Gheorghe M.,University of Sheffield | Pan L.,Huazhong University of Science and Technology | Perez-Jimenez M.J.,University of Seville
Information Sciences | Year: 2014

Evolutionary membrane computing is an important research direction of membrane computing that aims to explore the complex interactions between membrane computing and evolutionary computation. These disciplines are receiving increasing attention. In this paper, an overview of the evolutionary membrane computing state-of-the-art and new results on two established topics in well defined scopes (membrane-inspired evolutionary algorithms and automated design of membrane computing models) are presented. We survey their theoretical developments and applications, sketch the differences between them, and compare the advantages and limitations. © 2014 Elsevier Inc. All rights reserved.


Yin X.,Huazhong University of Science and Technology | Yue D.,Nanjing University of Posts and Telecommunications | Hu S.,Hubei University of Arts and Science
Journal of the Franklin Institute | Year: 2013

This paper investigates the consensus problem for a set of discrete-time heterogeneous multi-agent systems composed of two kinds of agents differed by their dynamics. The consensus control is designed based on the event-triggered communication scheme, which can lead to a significant reduction of the information communication burden in the multi-agent network. Meanwhile, only the communication between the agent and its local neighbors is needed, therefore, the designed control is essentially distributed. Based on the Lyapunov functional method and the Kronecker product technique, a sufficient condition is obtained to guarantee the consensus of heterogeneous multi-agent systems in terms of linear matrix inequality (LMI). Simulation results illustrate the effectiveness of the developed theory in the last.


Pan A.,Huazhong University of Science and Technology | Wang Y.,National University of Singapore | Talaei M.,National University of Singapore | Hu F.B.,Harvard University
Circulation | Year: 2015

Background - The prevalence of smoking in diabetic patients remains high, and reliable quantification of the excess mortality and morbidity risks associated with smoking is important for diabetes management. We performed a systematic review and meta-analysis of prospective cohort studies to evaluate the relation of active smoking with risk of total mortality and cardiovascular events among diabetic patients. Methods and Results - We searched Medline and Embase databases through May 2015, and multivariate-adjusted relative risks were pooled by using random-effects models. A total of 89 cohort studies were included. The pooled adjusted relative risk (95% confidence interval) associated with smoking was 1.55 (1.46-1.64) for total mortality (48 studies with 1 132 700 participants and 109 966 deaths), and 1.49 (1.29-1.71) for cardiovascular mortality (13 studies with 37 550 participants and 3163 deaths). The pooled relative risk (95% confidence interval) was 1.44 (1.34-1.54) for total cardiovascular disease (16 studies), 1.51 (1.41-1.62) for coronary heart disease (21 studies), 1.54 (1.41-1.69) for stroke (15 studies), 2.15 (1.62-2.85) for peripheral arterial disease (3 studies), and 1.43 (1.19-1.72) for heart failure (4 studies). In comparison with never smokers, former smokers were at a moderately elevated risk of total mortality (1.19; 1.11-1.28), cardiovascular mortality (1.15; 1.00-1.32), cardiovascular disease (1.09; 1.05-1.13), and coronary heart disease (1.14; 1.00-1.30), but not for stroke (1.04; 0.87-1.23). Conclusions - Active smoking is associated with significantly increased risks of total mortality and cardiovascular events among diabetic patients, whereas smoking cessation is associated with reduced risks in comparison with current smoking. The findings provide strong evidence for the recommendation of quitting smoking among diabetic patients. © 2015 American Heart Association, Inc.


Zhou Y.,Huazhong University of Science and Technology | Huang C.,Huazhong University of Science and Technology | Liao Q.,Huazhong University of Science and Technology | Lu P.,Huazhong University of Science and Technology | Lu P.,Key Laboratory of Fundamental Physical Quantities Measurement of Ministry of Education
Physical Review Letters | Year: 2012

With a classical ensemble model that includes electron correlations during the whole ionization process, we investigate strong-field sequential double ionization of Ar by elliptically polarized pulses at the quantitative level. The experimentally observed intensity-dependent three-band or four-band structures in the ion momentum distributions are well reproduced with this classical model. More importantly, the experimentally measured ionization time of the second electrons by A.N. Pfeiffer et al., which cannot be predicted by the standard independent-electron model, is quantitatively reproduced by this fully classical correlated model. The success of our work encourages classical descriptions and interpretations of the complex multielectron effects in strong-field ionization where nonperturbative quantum approaches are currently not feasible. © 2012 American Physical Society.


Song T.,Huazhong University of Science and Technology | Pan L.,Huazhong University of Science and Technology | Paun G.,University of Seville | Paun G.,Institute of Mathematics of the Romanian Academy
Information Sciences | Year: 2013

Spiking neural P systems (SN P systems, for short) are a class of distributed parallel computing devices inspired from the way neurons communicate by means of spikes. Asynchronous SN P systems are non-synchronized systems, where the use of spiking rules (even if they are enabled by the contents of neurons) is not obligatory. It remains open whether asynchronous SN P systems with standard spiking rules are equivalent with Turing machines. In this paper, with a biological inspiration (in order to achieve some specific biological functioning, neurons from the same functioning motif or community work synchronously to cooperate with each other), we introduce the notion of local synchronization into asynchronous SN P systems. The computation power of asynchronous SN P systems with local synchronization is investigated. Such systems consisting of general neurons (respectively, unbounded neurons) and using standard spiking rules are proved to be universal. Asynchronous SN P systems with local synchronization consisting of bounded neurons and using standard spiking rules characterize the semilinear sets of natural numbers. These results show that the local synchronization is useful, it provides some "programming capacity" useful for achieving a desired computation power. © 2012 Elsevier Inc. All rights reserved.


Vafai K.,University of California at Riverside | Yang K.,Huazhong University of Science and Technology
Transport in Porous Media | Year: 2013

This work address a number of fundamental issues and concepts related to local thermal non-equilibrium and the heat flux bifurcation phenomenon in porous media. Different types of heat flux bifurcation phenomenon are discussed in relation to previous works by the authors. © 2012 Springer Science+Business Media Dordrecht.


Derichter R.K.,National Graduate School of Chemistry, Montpellier | Ming T.,Huazhong University of Science and Technology | Caillol S.,National Graduate School of Chemistry, Montpellier
Renewable and Sustainable Energy Reviews | Year: 2013

Over the last decades, fighting global warming has become the most important challenge humanity has to face. Therefore technologies of carbon dioxide capture, sequestration and recycling are equally important in order to tackle the global climate change stakes. Among recycling technologies, photocatalytic processes reducing CO2 with H2O back to fuels or to other useful organic compounds, have the potential to be part of a renewable energy system. Indeed these processes can help to control CO 2 emissions and eventually eliminate CO2 in excess. This perspective paper describes a large size device, able simultaneously: • to proceed to direct air capture (DAC) of CO2; • to transform part of it into useful chemicals, like hydrocarbons or syngas; • and to produce renewable energy, thus preventing future CO2 emissions. Synergies between solar chimney power plants (SCPPs) and semiconductor photocatalysis in order to create giant photocatalytic reactors for artificial photosynthesis are discussed, as well as scale economies for unconventional carbon capture directly from the atmosphere. This paper presents a carbon negative emission technology obtained by coupling SCPPs with DAC systems which allows many scale economies, and also synergies to proceed to solar-to-chemical energy-conversion process by photocatalytic reduction of atmospheric CO2 under sunlight. © 2012 Elsevier Ltd.


Zhang Z.,Huazhong University of Science and Technology | Tan S.,Huazhong University of Science and Technology | Feng S.-S.,National University of Singapore
Biomaterials | Year: 2012

d-α-tocopheryl polyethylene glycol succinate (Vitamin E TPGS, or simply TPGS) is a water-soluble derivative of natural Vitamin E, which is formed by esterification of Vitamin E succinate with polyethylene glycol (PEG). As such, it has advantages of PEG and Vitamin E in application of various nanocarriers for drug delivery, including extending the half-life of the drug in plasma and enhancing the cellular uptake of the drug. TPGS has an amphiphilic structure of lipophilic alkyl tail and hydrophilic polar head with a hydrophile/lipophile balance (HLB) value of 13.2 and a relatively low critical micelle concentration (CMC) of 0.02% w/w, which make it to be an ideal molecular biomaterial in developing various drug delivery systems, including prodrugs, micelles, liposomes and nanoparticles, which would be able to realize sustained, controlled and targeted drug delivery as well as to overcome multidrug resistance (MDR) and to promote oral drug delivery as an inhibitor of P-glycoprotein (P-gp). In this review, we briefly discuss its physicochemical and pharmaceutical properties and its wide applications in composition of the various nanocarriers for drug delivery, which we call TPGS-based drug delivery systems. © 2012 Elsevier Ltd.


Liu J.,Donghua University | Liu J.,Nanjing Forestry University | Yue D.,Huazhong University of Science and Technology
International Journal of Robust and Nonlinear Control | Year: 2012

SUMMARY In this paper, we propose and investigate a new general model of fuzzy genetic regulatory networks described by the Takagi-Sugeno (T-S) fuzzy model with time-varying delays. By using a Lyapunov functional approach and linear matrix inequality (LMI) techniques, the stability criteria for the delayed fuzzy genetic regulatory networks are expressed as a set of LMIs, which can be solved numerically by LMI toolbox in Matlab. Two fuzzy genetic network example are given to verify the effectiveness and applicability of the proposed approach. © 2011 John Wiley & Sons, Ltd.


Yang K.,Huazhong University of Science and Technology | Yang K.,University of California at Riverside | Vafai K.,University of California at Riverside
International Journal of Heat and Mass Transfer | Year: 2010

The phenomenon of temperature gradient bifurcation in a porous medium is analyzed by studying the convective heat transfer process within a channel filled with a porous medium, with internal heat generation. A local thermal non-equilibrium (LTNE) model is used to represent the energy transport within the porous medium. Exact solutions are derived for both the fluid and solid temperature distributions for two primary approaches (Models A and B) for the constant wall heat flux boundary condition. The Nusselt number for the fluid at the channel wall is also obtained. The effects of the pertinent parameters such as fluid and solid internal heat generations, Biot number and fluid to solid thermal conductivity ratio are discussed. It is shown that the internal heat generation in the solid phase is significant for the heat transfer characteristics. The validity of the one equation model is investigated by comparing the Nusselt number obtained from the LTNE model with that from the local thermal equilibrium (LTE) model. The results demonstrate the importance of utilizing the LTNE model in the present study. The phenomenon of temperature gradient bifurcation for the fluid and solid phases at the wall for Model A is established and demonstrated. In addition, the temperature distributions for Models A and B are compared. A numerical study for the constant temperature boundary condition was also carried out. It was established that the phenomenon of temperature gradient bifurcation for the fluid and solid phases for the constant temperature boundary condition can occur over a given axial region. © 2010 Elsevier Ltd.


Yue D.,Nanjing University of Posts and Telecommunications | Yue D.,Huazhong University of Science and Technology | Tian E.,Nanjing Normal University | Han Q.-L.,Central Queensland University
IEEE Transactions on Automatic Control | Year: 2013

This note is concerned with event-triggered $H\infty controller design for networked control systems. A novel event-triggering scheme is proposed, which has some advantages over some existing schemes. A delay system model for the analysis is firstly constructed by investigating the effect of the network transmission delay. Then, based on this model, criteria for stability with an $H\infty norm bound and criteria for co-designing both the feedback gain and the trigger parameters are derived. These criteria are formulated in terms of linear matrix inequalities. Simulation results have shown that the proposed event-triggering scheme is superior to some existing event-triggering schemes in the literature. © 2012 IEEE.


Lu X.,Huazhong University of Science and Technology | Laroussi M.,Old Dominion University | Puech V.,University Paris - Sud
Plasma Sources Science and Technology | Year: 2012

Atmospheric-pressure non-equilibrium plasma jets (APNP-Js), which generate plasma in open space rather than in a confined discharge gap, have recently been a topic of great interest. In this paper, the development of APNP-Js will be reviewed. Firstly, the APNP-Js are grouped based on the type of gas used to ignite them and their characteristics are discussed in detail. Secondly, one of the most interesting phenomena of APNP-Js, the plasma bullet, is discussed and its behavior described. Thirdly, the very recent developments on the behavior of plasma jets when launched in a controlled environment and pressure are also introduced. This is followed by a discussion on the interaction between plasma jets. Finally, perspectives on APNP-J research are presented. © 2012 IOP Publishing Ltd.


Zhou Y.,Huazhong University of Science and Technology | Huang C.,Huazhong University of Science and Technology | Lu P.,Huazhong University of Science and Technology | Lu P.,Key Laboratory of Fundamental Physical Quantities Measurement of Ministry of Education
Optics Express | Year: 2012

We theoretically investigated sequential double ionization (SDI) of Ar by the nearly circularly polarized laser pulses with a fully correlated classical ensemble model. The ion momentum distributions of our numerical results at various laser intensities and pulse durations agree well with the experimental results. The experimentally observed multi-electron effects embodied in the joint momentum spectrum of the two electrons is also reproduced by our correlated classical calculations. Interestingly, our calculations show that the angular distribution of the first photoelectron from the trajectories which eventually suffer SDI differs from the distribution of the photoelectrons from above-threshold ionization trajectories. This observation provides additional evidence of multi-electron effects in strong field SDI. © 2012 Optical Society of America.


Yang K.,Huazhong University of Science and Technology | Vafai K.,University of California at Riverside
International Journal of Heat and Mass Transfer | Year: 2011

The phenomenon of heat flux bifurcation inside a porous medium is analyzed by studying the convective heat transfer process within a channel partially filled with a porous medium under Local Thermal Non-Equilibrium (LTNE) conditions. Either the thermal dispersion effect or the inertial effect is considered in the physical model. Exact solutions are derived for both the fluid and solid temperature distributions for three interface thermal models at the porous-fluid interface. The required conditions for validity of each interface thermal model are obtained, and the equivalence correlations between different interface thermal models are developed. The range of validity of the Local Thermal Equilibrium (LTE) condition is established, and the phenomenon of heat flux bifurcation inside a porous medium is established and demonstrated for the first time in the literature. Furthermore, the Nusselt number is obtained and investigated for pertinent parameters. The ranges of physical parameters in which the thermal dispersion effect and the inertia effect are important are established. © 2011 Elsevier Ltd. All rights reserved.


Fu H.-H.,Huazhong University of Science and Technology | Yao K.-L.,Huazhong University of Science and Technology
Applied Physics Letters | Year: 2012

We report a design to realize perfect spin-filter and highly spin-polarized current in a quantum network device composed of multiple quantum dots (QDs). By producing an energy difference between the site energy of the upper QDs and down ones, the linear conductance spectra present well-defined insulating bands with very steep edges due to the Fano antiresonance in some suitable conditions. Considering a Zeeman splitting, highly to 100% spin-polarized windows appear in the conductance spectra, which makes the network device can be used as a perfect spin filter to generate completely spin-polarized current. This idea opens a practical way to prompt other similar configures of the network to realize perfect spin-filter. © 2012 American Institute of Physics.


Li T.,Shanghai University | Wu F.,Huazhong University of Science and Technology | Zhang J.-F.,CAS Academy of Mathematics and Systems Science
IEEE Transactions on Automatic Control | Year: 2014

In this note, the distributed consensus corrupted by relative-state- dependent measurement noises is considered. Each agent can measure or receive its neighbors' state information with random noises, whose intensity is a vector function of agents' relative states. By investigating the structure of this interaction and the tools of stochastic differential equations, we develop several small consensus gain theorems to give sufficient conditions in terms of the control gain, the number of agents and the noise intensity function to ensure mean square (m.s.) and almost sure (a.s.) consensus and quantify the convergence rate and the steady-state error. Especially, for the case with homogeneous communication and control channels, a necessary and sufficient condition to ensure m.s. consensus on the control gain is given and it is shown that the control gain is independent of the specific network topology, but only depends on the number of nodes and the noise coefficient constant. For symmetric measurement models, the almost sure convergence rate is estimated by the Iterated Logarithm Law of Brownian motions. © 2014 IEEE.


Pan J.,Huazhong University of Science and Technology | Chen Q.,Huazhong University of Science and Technology | Liu L.,Huazhong University of Science and Technology | Li Y.,National University of Singapore
Acta Materialia | Year: 2011

Shear band is the key feature that controls the plastic deformation process of metallic glasses (MGs). However, the investigation directly on the shear band and its properties is rarely conducted as the band is perceived as extremely narrow. We have conducted a controlled experiment to form a single shear band in the specimen, which enabled us to probe shear-induced softening and dilatation directly on the shear band itself. Extreme dilatation and free volume increase as high as 1.14% and 1.40% respectively, have been observed, resulting from a drastic structure change due to severe plastic flow in the band. Nanoindentation on the individual shear band reveals significant softening of 36% and an unexpected wide width up to 160 μm, three magnitudes higher than what has been reported. These prove beyond doubt the dilatation as a mechanism for softening. The correlation between the free volume content and softening is discussed. Our findings provide a new insight for understanding the deformation behavior of metallic glass. © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Grant
Agency: Cordis | Branch: FP7 | Program: CSA-CA | Phase: HEALTH.2011.3.4-2 | Award Amount: 2.20M | Year: 2011

This project will add new research training capacity at low and middle-income countries (LMICs) in Asia, for promoting research on social determinants of health (RSDH). The focus is doctoral and post doctoral training, institutional strengthening for education, financial and administrative research management, and LMICs-based network building. Novel capacity building approaches will reduce brain drain, be more climate friendly and encourage gender equity with LMICs-based training. Internet mounted downloadable modules in related disciplines, like epidemiology, anthropology, economic methods, etc., will support excellent interdisciplinary courses. Addressing social determinants of health and tackling health inequity are research intensive, incremental improvement to measurement and understanding, implementation and evaluation. Therefore LMICs need to grow their own capacity to strengthen RSDH: interdisciplinary, rigorous and relevant. ARCADE-RSDH will support evidence informed decision making by producing a stream of well-trained young RSDH scientists, the next generation of health system leaders and researchers in LMICs. Activities will be aimed at individuals, institutions and the network. Tongji Medical College of HUST (TJMC, China), CBCI Society of Medical Education (SJNAHS, India) and Public Health Foundation of India (PHFI, India) are strong Asian Universities with RSDH focus. They will act as hubs in a network including TJMC, SJNAHS, PHFI, Beijing Normal University (BNU, China), Zhejiang University (ZJU, China), Indian Institute of Health Management Research (IIHMR, India), Ruxmaniben Deepchand Gardi Medical College (UCTH, India) and initially Sultan Qaboos University (SQU, Oman), Hanoi Medical University (HMU, Vietnam), working with strong European RSDH institutions (Karolinska Institutet KI, Sussex University Institutet for Development Studies IDS and University of Tampere UTA). This region-wide approach will draw skills, resources and students to a new LMICs-based RSDH capacity development network.


Grant
Agency: Cordis | Branch: H2020 | Program: CSA | Phase: ICT-37-2016 | Award Amount: 2.56M | Year: 2017

Europe and China are at the forefront of technological advances in areas related to the Future Internet (especially 5G and IoT). While both parties share common technological objectives, there is still room for improvement in what concerns bilateral co-operation. As a result, the main purpose of EXCITING is to support the creation of favourable conditions for co-operation between the European and Chinese research and innovation ecosystems, mainly related to the key strategic domains of IoT and 5G. EXCITING will study the research and innovation ecosystem for IoT and 5G in China and compare it with the European model. EXCITING will identify and document the key international standards bodies for IoT and 5G, as well as other associations and fora where discussions take place and implementation decisions are made. Going beyond standardisation, interoperability testing is a key step towards market deployment. EXCITING will identify and document the key international InterOp events at which European and Chinese manufacturers can test and certify their IoT and 5G products. It will also explain the rules for engaging in these events. EXCITING will produce Best Practice guidelines for establishing and operating practical joint collaborations, in order to stimulate further such co-operations in the future on IoT and 5G Large Scale Pilots. As a result of the above investigations EXCITING will produce a roadmap showing how research and innovation ecosystems, policy, standardisation, interoperability testing and practical Large Scale Pilots should be addressed during the H2020 timeframe, and make recommendations for optimising collaboration between Europe and China for IoT and 5G.


Zhang G.,Zhengzhou Institute of Aeronautical Industry Management | Gao L.,Huazhong University of Science and Technology | Shi Y.,Huazhong University of Science and Technology
Expert Systems with Applications | Year: 2011

In this paper, we proposed an effective genetic algorithm for solving the flexible job-shop scheduling problem (FJSP) to minimize makespan time. In the proposed algorithm, Global Selection (GS) and Local Selection (LS) are designed to generate high-quality initial population in the initialization stage. An improved chromosome representation is used to conveniently represent a solution of the FJSP, and different strategies for crossover and mutation operator are adopted. Various benchmark data taken from literature are tested. Computational results prove the proposed genetic algorithm effective and efficient for solving flexible job-shop scheduling problem. © 2010 Elsevier Ltd. All rights reserved.


Wang X.,Shanghai JiaoTong University | Su H.,Huazhong University of Science and Technology
Annual Reviews in Control | Year: 2014

In practice, directly control every node in a dynamical networked system with a huge number of nodes might be impossible or unnecessary; therefore, pinning control is a desirable approach. This paper surveys advances in pinning control approaches to making a dynamical networked system have a desired behavior. For a network with fixed topology, we review the feasibility, stability and effectiveness of pinning control. We then focus on pinning-based consensus and flocking control of mobile multi-agent networked systems. One of the main challenges with consensus and flocking control is that the topology of the corresponding dynamical network is time-varying, which depends on the states of all the agents in the network. Looking forward to the next decade, we expect to have a much deeper understanding of the relationship between the effectiveness of pinning control and the structural properties of a complex network, which may result in better control of large scale networked systems. © 2014 Elsevier Ltd. All rights reserved.


Chow E.K.-H.,University of California at San Francisco | Fan L.-L.,University of California at San Francisco | Fan L.-L.,Huazhong University of Science and Technology | Chen X.,University of California at San Francisco | Bishop J.M.,University of California at San Francisco
Hepatology | Year: 2012

At least some cancer stem cells (CSCs) display intrinsic drug resistance that may thwart eradication of a malignancy by chemotherapy. We explored the genesis of such resistance by studying mouse models of liver cancer driven by either MYC or the combination of oncogenic forms of activation of v-akt murine thymoma viral oncogene homolog (AKT) and NRAS. A common manifestation of chemoresistance in CSCs is efflux of the DNA-binding dye Hoechst 33342. We found that only the MYC-driven tumors contained a subset of cells that efflux Hoechst 33342. This "side population" (SP) was enriched for CSCs when compared to non-SP tumor cells and exhibited markers of hepatic progenitor cells. The SP cells could differentiate into non-SP tumor cells, with coordinate loss of chemoresistance, progenitor markers, and the enrichment for CSCs. In contrast, non-SP cells did not give rise to SP cells. Exclusion of Hoechst 33342 is mediated by ATP binding cassette drug transporter proteins that also contribute to chemoresistance in cancer. We found that the multidrug resistance gene 1 (MDR1) transporter was responsible for the efflux of Hoechst from SP cells in our MYC-driven model. Accordingly, SP cells and their tumor-initiating subset were more resistant than non-SP cells to chemotherapeutics that are effluxed by MDR1. Conclusion: The oncogenotype of a tumor can promote a specific mechanism of chemoresistance that can contribute to the survival of hepatic CSCs. Under circumstances that promote differentiation of CSCs into more mature tumor cells, the chemoresistance can be quickly lost. Elucidation of the mechanisms that govern chemoresistance in these mouse models may illuminate the genesis of chemoresistance in human liver cancer. © 2012 American Association for the Study of Liver Diseases.


Su H.,Huazhong University of Science and Technology | Zhang N.,Huazhong University of Science and Technology | Chen M.Z.Q.,University of Hong Kong | Wang H.,Huazhong University of Science and Technology | Wang X.,Shanghai JiaoTong University
Nonlinear Analysis: Real World Applications | Year: 2013

This paper investigates adaptive flocking of multi-agent systems (MASs) with a virtual leader. All agents and the virtual leader share the same intrinsic nonlinear dynamics, which satisfies a locally Lipschitz condition and depends on both position and velocity information for the agent itself. Under the assumption that the initial network is connected, an approach to preserving the connectivity of the network is proposed. On the basis of the Lyapunov stability theory, an adaptive flocking control law is derived, for making the MASs track the virtual leader without collision. Finally, a numerical example is presented to illustrate the effectiveness of the theoretical results. © 2012 Published by Elsevier Ltd.


Shi Y.,Huazhong University of Science and Technology | Liu H.,Huazhong University of Science and Technology | Gao L.,Huazhong University of Science and Technology | Zhang G.,Zhengzhou Institute of Aeronautical Industry Management
Information Sciences | Year: 2011

This paper proposes a cellular particle swarm optimization (CPSO), hybridizing cellular automata (CA) and particle swarm optimization (PSO) for function optimization. In the proposed CPSO, a mechanism of CA is integrated in the velocity update to modify the trajectories of particles to avoid being trapped in the local optimum. With two different ways of integration of CA and PSO, two versions of CPSO, i.e. CPSO-inner and CPSO-outer, have been discussed. For the former, we devised three typical lattice structures of CA used as neighborhood, enabling particles to interact inside the swarm; and for the latter, a novel CA strategy based on "smart-cell" is designed, and particles employ the information from outside the swarm. Theoretical studies are made to analyze the convergence of CPSO, and numerical experiments are conducted to compare the proposed algorithm with different variants of PSO. According to the experimental results, the proposed method performs better than other variants of PSO on benchmark test functions. © 2011 Elsevier Inc. All rights reserved.


Su H.,Huazhong University of Science and Technology | Chen M.Z.Q.,University of Hong Kong | Wang X.,Shanghai JiaoTong University | Lam J.,University of Hong Kong
IEEE Transactions on Industrial Electronics | Year: 2014

This paper studies the observer-based leader-following consensus of a linear multiagent system on switching networks, in which the input of each agent is subject to saturation. Based on a low-gain output feedback method, distributed consensus protocols are developed. Under the assumptions that the networks are connected or jointly connected and that each agent is asymptotically null controllable with bounded controls and detectable, semiglobal observer-based leader-following consensus of the multiagent system can be reached on switching networks. A numerical example is presented to illustrate the theoretical results. © 1982-2012 IEEE.


Zhang J.,Huazhong University of Science and Technology | Zhang J.,University Paris - Sud | Cassan E.,University Paris - Sud | Zhang X.,Huazhong University of Science and Technology
Optics Letters | Year: 2013

We theoretically investigate the quadratic nonlinear property of a silicon-organic hybrid plasmonic waveguide with a thin polymer layer deposited on top of a silicon slab and covered by a metal cap. Due to the hybridization property of the waveguide modes, efficient phase-matched second harmonic generation (SHG) from mid-infrared (IR) (-3.1 μm) to near-IR (-1.55 μm) wavelengths are achieved with a small fabrication-error sensitivity (225 nm ≤ tolerated waveguide width ≤ 378 nm) and a large bandwidth (Δλ = 100 nm). The SHG yield is as large as 8.8% for a pumping power of 100 mW. © 2013 Optical Society of America.


Wang B.,Huazhong University of Science and Technology | Guan Z.-H.,Huazhong University of Science and Technology | Yuan F.-S.,Anyang University, South Korea
Automatica | Year: 2011

In this paper, the optimal tracking problem under control energy constraint is studied. The disturbance in the upstream channel and down channel is adequately considered. Some new results are derived and it is shown that the performance limitation is tightly dependent on the non-minimum phase zeros and the unstable poles. In addition, the performance limitation, which is greater than that of the disturbance only in the down channel, depends on other new non-minimum phase zeros. Finally, the example explains and validates the conclusion. © 2011 Elsevier Ltd. All rights reserved.


Guo X.,Huazhong University of Science and Technology | Guo X.,Jülich Research Center
Physical Chemistry Chemical Physics | Year: 2014

As a classic dielectric material, BaTiO3 is one of the most important materials used in electronic applications. In this work, highly dense BaTiO3 ceramics with an average grain size of 35 nm were prepared, and dielectric and electrical properties were investigated. Microcrystalline BaTiO3 is an insulator at low temperatures; however, nanocrystalline BaTiO3 shows considerable semiconductivity with an activation energy of only 0.27 eV at temperatures ≤200 °C. At room temperature, the conductivity of nanocrystalline BaTiO3 is about fourteen orders of magnitude higher than that of the microcrystalline counterpart. Only by decreasing the grain size, one can transform BaTiO3 from an insulator to a semiconductor. © the Owner Societies 2014.


Zhao L.,CAS Institute of Physics | Zhao J.,CAS Institute of Process Engineering | Hu Y.-S.,CAS Institute of Physics | Li H.,CAS Institute of Physics | And 4 more authors.
Advanced Energy Materials | Year: 2012

In this contribution, a cheap organic material, disodium terephthalate, Na 2C 8H 4O 4, has been firstly evaluated as a novel anode for room-temperature Na-ion batteries. The material exhibits a high reversible capacity of 250 mAh/g with excellent cycleability. The average Na storage voltage is approximately 0.43 V vs. Na +/Na. A thin layer of Al 2O 3 coating on the electrode surface derived from the atomic layer deposition technique is effective in further enhancing Na storage performance. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Guo X.,Huazhong University of Science and Technology | Guo X.,Jülich Research Center
Acta Materialia | Year: 2013

Dense BaTiO3 ceramics with grain sizes of 35 nm to 5.6 μm were prepared, and the electrical properties investigated in the temperature range 500-700 °C by means of impedance spectroscopy. Charge carriers (oxygen vacancies and holes) are depleted in the space charge regions at the BaTiO 3 grain boundaries. When the grain size is ≥250 nm, the width of the space charge region was determined to be ∼40 nm. Therefore, the depletion regions were expected to overlap when the grain size decreases to 35 nm; in such a situation, charge carriers would be depleted over the entire grain, resulting in depressed conductivity. However, the conductivity of the 35 nm grain size sample was measured to be one to two orders of magnitude higher than those of the microcrystalline samples, and the activation energy markedly lower. Moreover, we determined a width of ∼7 nm for the space charge regions in the 35 nm grain size sample; therefore, the space charge regions do not overlap. The enhanced conductivity is ascribed to a reduced oxidation enthalpy in nanocrystalline BaTiO3, and the distorted grain boundaries in nanocrystalline BaTiO3 are believed to be the atomic level origin of the reduced oxidation enthalpy. © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Zhang X.,Huazhong University of Science and Technology | Zhang X.,Hubei Key Laboratory of Engineering Structural | Zhang H.,Wuhan Textile University
Composite Structures | Year: 2013

The out-of-plane crushing properties of rhombic and kagome honeycombs are studied in this paper by dividing the whole structure into basic angle elements: corner elements and X-shaped elements. Two theoretical models are presented to analyze the energy absorption mechanisms for inextensional mode of corner elements and one of collapse modes of X-shaped elements respectively. Expressions are derived to predict the mean crushing force of the angle elements. Numerical simulations are also carried out for angle elements under out-of-plane crushing by using nonlinear finite element code LS-DYNA. Crush resistance of angle elements with different geometric configurations including angle, width and thickness is analyzed. A comparison between theoretical predictions and numerical results shows that the theoretical models can effectively predict the mean crushing force of angle elements with a very good accuracy. © 2012 Elsevier Ltd.


Chen J.,Key Laboratory of Image Information Processing and Intelligent Control | Zeng Z.,Huazhong University of Science and Technology | Jiang P.,Key Laboratory of Image Information Processing and Intelligent Control
Information Sciences | Year: 2014

In this paper, we study the existence, uniqueness and stability of periodic solution for a wide class of memristor-based neural networks with time-varying delays. By employing the topological degree theory in set-valued analysis, differential inclusions theory and a new Lyapunov function method, we prove that the neural network has a unique periodic solution, which is globally exponentially stable. Moreover, we prove the existence, uniqueness and global exponential stability of equilibrium point for time-varying delayed memristor-based neural networks with constant coefficients. The obtained results improve and extend previous works on memristor-based or usual neural network dynamical systems with continuous or discontinuous right-hand side. Finally, two numerical examples are provided to show the applicability and effectiveness of our main results. © 2014 Elsevier Inc. All rights reserved.


Luo Q.,Nanjing University of Information Science and Technology | Mao X.,University of Strathclyde | Shen Y.,Huazhong University of Science and Technology
Automatica | Year: 2011

Asymptotic stability and boundedness have been two of most popular topics in the study of stochastic functional differential equations (SFDEs) (see e.g. Appleby and Reynolds (2008), Appleby and Rodkina (2009), Basin and Rodkina (2008), Khasminskii (1980), Mao (1995), Mao (1997), Mao (2007), Rodkina and Basin (2007), Shu, Lam, and Xu (2009), Yang, Gao, Lam, and Shi (2009), Yuan and Lygeros (2005) and Yuan and Lygeros (2006)). In general, the existing results on asymptotic stability and boundedness of SFDEs require (i) the coefficients of the SFDEs obey the local Lipschitz condition and the linear growth condition; (ii) the diffusion operator of the SFDEs acting on a C2,1-function be bounded by a polynomial with the same order as the C2,1-function. However, there are many SFDEs which do not obey the linear growth condition. Moreover, for such highly nonlinear SFDEs, the diffusion operator acting on a C2,1-function is generally bounded by a polynomial with a higher order than the C2,1-function. Hence the existing criteria on stability and boundedness for SFDEs are not applicable and we see the necessity to develop new criteria. Our main aim in this paper is to establish new criteria where the linear growth condition is no longer needed while the up-bound for the diffusion operator may take a much more general form. © 2011 Elsevier Ltd. All rights reserved.


Su H.,Huazhong University of Science and Technology | Chen G.,City University of Hong Kong | Wang X.,Shanghai JiaoTong University | Lin Z.,University of Virginia
Automatica | Year: 2011

We investigate second-order consensus of multiple nonlinear dynamical mobile agents with a virtual leader in a dynamic proximity network. We assume that only a small fraction of agents in the group have access to the information about the position and velocity of the virtual leader through, for example, certain pre-designed communication mechanism such as wireless broadcasting or sensing. To avoid fragmentation, we propose a connectivity-preserving second-order consensus algorithm. Under the assumption that the initial network is connected, we introduce local adaptation strategies for both the weights on the velocity navigational feedback and the velocity coupling strengths that enable all agents to synchronize with the virtual leader even when only one agent is informed, without requiring any knowledge of the agent dynamics. We finally provide some convincing simulation results to illustrate the theoretical results. © 2010 Elsevier Ltd. All rights reserved.


Grant
Agency: Cordis | Branch: FP7 | Program: CSA | Phase: INFRA-2010-3.3 | Award Amount: 871.70K | Year: 2010

The FP7 EDGeS project has successfully set up a production-level distributed computing infrastructure (DCI) consisting of more than 100.000 PCs from several volunteer and low-cost Desktop Grids, which have been connected to existing Service Grids (including EGEE, SEE-GRID, etc. with about 150.000 processors) based on the new 3G Bridge technology and application development methodology.\n\nThe main aim of the DEGISCO project is the further extension of the European DCI infrastructure that is already interconnected by EDGeS to International Cooperation Partner Countries (ICPC) in strong collaboration with on the one hand local partners in ICPC countries and on the other hand European e-Infrastructure experts (including 3G Bridge know-how) and thus, reinforce the global relevance and impact of European distributed infrastructures.\n\nThe project will support the creation of new Desktop Grids in ICPC countries and the connection of these Grids to European DCIs and existing Service Grids in ICPC countries by employing 3G Bridge technology. Moreover, building on the solid expertise of the DEGISCO partners, the project will provide recommendations on best practices and define joint roadmaps for ICPC countries and Europe.\n\nThe application support activities of DEGISCO support the use of the already two dozen ported applications on new connected DCIs in ICPC countries and support new applications.\n\nThe dissemination and training activities will promote via various channels such interoperation between Desktop Grid and Service Grid infrastructures on a global scale, which leads to more awareness under the general public of computational science and distributed computing co-funded by the EC. As a result more citizens, students, and companies are expected to donate resources to scientific purposes.\n\n\nAs part of these activities an International Desktop Grid Federation will be operated allowing for effective exchange of information through participation.


Zhou Y.,Huazhong University of Science and Technology | Ramstrom O.,KTH Royal Institute of Technology | Dong H.,Huazhong University of Science and Technology
Chemical Communications | Year: 2012

Organosilicon-mediated, regioselective acetylation of vicinal- and 1,3-diols is presented. Methyl trimethoxysilane or dimethyl dimethoxysilane was first used to form cyclic 1,3,2-dioxasilolane or 1,3,2-dioxasilinane intermediates, and subsequent acetate-catalyzed monoacylation was efficiently performed by addition of acetic anhydride or acetyl chloride under mild conditions. The reaction exhibited high regioselectivity, resulting in the same protection pattern as in organotin-mediated schemes. © 2012 The Royal Society of Chemistry.


Ding Y.,Shanghai JiaoTong University | Zhu L.,Shanghai JiaoTong University | Zhang X.,Huazhong University of Science and Technology | Ding H.,Shanghai JiaoTong University
International Journal of Machine Tools and Manufacture | Year: 2010

This paper presents a full-discretization method based on the direct integration scheme for prediction of milling stability. The fundamental mathematical model of the dynamic milling process considering the regenerative effect is expressed as a linear time periodic system with a single discrete time delay, and the response of the system is calculated via the direct integration scheme with the help of discretizing the time period. Then, the Duhamel term of the response is solved using the full-discretization method. In each small time interval, the involved system state, time-periodic and time delay items are simultaneously approximated by means of linear interpolation. After obtaining the discrete map of the state transition on one time interval, a closed form expression for the transition matrix of the system is constructed. The milling stability is then predicted based on Floquet theory. The effectiveness of the algorithm is demonstrated by using the benchmark examples for one and two degrees of freedom milling models. It is shown that the proposed method has high computational efficiency without loss of any numerical precision. The code of the algorithm is also attached in the appendix. Crown Copyright © 2010.


Guo X.,Huazhong University of Science and Technology | Guo X.,Jülich Research Center
Applied Physics Letters | Year: 2012

Single crystalline SrTiO 3 was used as a model system to evaluate the roles of the Schottky barrier and oxygen vacancies in electroforming. An advantage of single crystalline SrTiO 3 is that the electrochemical processes at intermediate temperatures have been thoroughly investigated. To take this advantage, the electroforming was performed at 200 °C and subsequently at 24 °C; an electrical stress of 4 × 10 3 V/cm, which was about two orders of magnitude lower than the electrical stress in previous works, decreased the cell resistance by orders of magnitude. After the electroforming, bipolar resistive switching was realized at 24 °C. © 2012 American Institute of Physics.


Naradikian M.S.,University of Pennsylvania | Hao Y.,Huazhong University of Science and Technology | Cancro M.P.,University of Pennsylvania
Immunological Reviews | Year: 2016

A subset of B cells with unique phenotypic and functional features-termed Age-associated B cells (ABCs)-has recently been identified in both mice and humans. These cells are characterized by a T-BET driven transcriptional program, robust responsiveness to TLR7 and TLR9 ligands, and a propensity for IgG2a/c production. Beyond their age-related accumulation, these cells play roles in both normal and pathogenic humoral immune responses regardless of host age. Thus, B cells with the ABC phenotype and transcriptional signature appear during viral, bacterial, and parasitic infections, but also arise during humoral autoimmune disease in both mouse models and humans. These observations suggest that both autoantigens and certain classes of pathogens provide the signals required for ABC differentiation. Herein, we review the discovery and features of ABCs, and propose that they are a memory subset generated by nucleic acid-containing antigens in the context of a promoting inflammatory cytokine milieu. © 2016 John Wiley & Sons A/S.


McCracken R.A.,Heriot - Watt University | Sun J.,Huazhong University of Science and Technology | Leburn C.G.,Heriot - Watt University | Reid D.T.,Heriot - Watt University
Optics Express | Year: 2012

The carrier-envelope-offset frequencies of the pump, signal, idler and related second-harmonic and sum-frequency mixing pulses have been locked to 0 Hz in a 20-fs-Ti:sapphire-pumped optical parametric oscillator satisfying a critical prerequisite for broadband optical pulse synthesis. With outputs spanning 400 -3200 nm, this result represents the broadest zerooffset comb demonstrated to date. ©2012 Optical Society of America.


Chang H.,Tohoku University | Chang H.,Huazhong University of Science and Technology | Wu H.,Tohoku University | Wu H.,Hong Kong University of Science and Technology
Energy and Environmental Science | Year: 2013

Graphene, a two-dimensional carbon sheet with one atom thickness and one of the thinnest materials in universe, has inspired huge interest in physics, materials science, chemistry and biology. However, pure graphene sheets are limited for many applications despite their excellent characteristics and scientists face challenges to induce more and controlled functionality. Therefore graphene nanocomposites or hybrids are attracting increasing efforts for real applications in energy and environmental areas by introducing controlled functional building blocks to graphene. In this Review, we first give a brief introduction of graphene's unique physical and chemical properties followed by various preparation and functionalization methods for graphene nanocomposites in the second section. We focus on recent energy-related progress of graphene nanocomposites in solar energy conversion (e.g., photovoltaic and photoelectrochemical devices, artificial photosynthesis) and electrochemical energy devices (e.g., lithium ion battery, supercapacitor, fuel cell) in the third section. We then review the advances in environmental applications of functionalized graphene nanocomposites for the detection and removal of heavy metal ions, organic pollutants, gas and bacteria in the fourth section. Finally a conclusion and perspective is given to discuss the remaining challenges for graphene nanocomposites in energy and environmental science. © 2013 The Royal Society of Chemistry.


Zhu X.-F.,Huazhong University of Science and Technology | Zhu X.-F.,CAS Shanghai Institute of Microsystem and Information Technology
Optics Express | Year: 2015

We investigated defect states in band gaps of one-dimensional photonic lattices with delicate modulations of gain and loss that respect parity-time-symmetry (PT-symmetry), viz. n(z) = n∗(-z). For the sake of generality, we employ not only periodic structures but also quasiperiodic structures, e.g. Fibonacci sequences, to construct aperiodic PT lattices. Differed from lossless systems for which the defect state is related to only one exceptional point (EP) of the S-matrix, we observed the splitting of one EP into a pair after the introduction of judiciously designed gain and loss in those PT systems, where the defect state enters a non-threshold broken symmetry phase bounded by the EP pair. Some interesting properties associated with defect states and EP splitting are demonstrated, such as enhanced spectral localization, double optical phase abrupt change, and wavelength sensitive reversion of unidirectional transparency. © 2015 Optical Society of America.


Tan S.,Huazhong University of Science and Technology | Li X.,Huazhong University of Science and Technology | Guo Y.,National Engn Research Center Antibody Med | Zhang Z.,Huazhong University of Science and Technology
Nanoscale | Year: 2013

Recent advances in nanotechnology and material sciences have promoted the development of nanomedicine. Among the formulations developed, novel lipid-enveloped hybrid nanoparticles have attracted more attention because of their special structure, properties and clinical applicability. The hybrid nanoparticles are composed of a hydrophilic PEG shell, a nano-sized polymeric or inorganic core and a lipid mono- or bi-layer between the core and PEG shell. This kind of nanoparticle possesses both the characteristics of liposomes and nanoparticles which endows it with many advantages like long circulation, high drug loading efficiency, high stability and biocompatibility, controlled release properties, and drug cocktail delivery. This review describes the recent developments of lipid-enveloped hybrid nanoparticles in cancer treatment, including the fabrication methods, formulations and applications of these hybrid nanoparticles. We expect that the continuing development of lipid-based nanomedicine will greatly improve cancer treatment. © 2013 The Royal Society of Chemistry.


Lu H.-J.,University of Nevada, Las Vegas | Zhang B.,University of Nevada, Las Vegas | Lei W.-H.,Huazhong University of Science and Technology | Li Y.,University of Nevada, Las Vegas | And 2 more authors.
Astrophysical Journal | Year: 2015

One favored progenitor model for short duration gamma-ray bursts (GRBs) is the coalescence of two neutron stars (NS-NS). One possible outcome of such a merger would be a rapidly spinning, strongly magnetized neutron star (known as a millisecond magnetar). These magnetars may be "supra-massive," implying that they would collapse to black holes after losing centrifugal support due to magnetic dipole spin down. By systematically analyzing the Burst Alert Telescope (BAT)-XRT light curves of all short GRBs detected by Swift, we test how consistent the data are with this central engine model of short GRBs. We find that the so-called "extended emission" feature observed with BAT in some short GRBs is fundamentally the same component as the "internal X-ray plateau" observed in many short GRBs, which is defined as a plateau in the light curve followed by a very rapid decay. Based on how likely a short GRB is to host a magnetar, we characterize the entire Swift short GRB sample into three categories: the "internal plateau" sample, the "external plateau" sample, and the "no plateau" sample. Based on the dipole spin-down model, we derive the physical parameters of the putative magnetars and check whether these parameters are consistent with expectations from the magnetar central engine model. The derived magnetar surface magnetic field and the initial spin period P0 fall into a reasonable range. No GRBs in the internal plateau sample have a total energy exceeding the maximum energy budget of a millisecond magnetar. Assuming that the beginning of the rapid fall phase at the end of the internal plateau is the collapse time of a supra-massive magnetar to a black hole, and applying the measured mass distribution of NS-NS systems in our Galaxy, we constrain the neutron star equation of state (EOS). The data suggest that the NS EOS is close to the GM1 model, which has a maximum non-rotating NS mass of . © 2015. The American Astronomical Society. All rights reserved.


Ding X.,Huazhong University of Science and Technology | Lian X.,Hong Kong University of Science and Technology | Chen L.,Hong Kong University of Science and Technology | Jin H.,Huazhong University of Science and Technology
Information Sciences | Year: 2012

Uncertain data are inevitable in many applications due to various factors such as the limitations of measuring equipment and delays in data updates. Although modeling and querying uncertain data have recently attracted considerable attention from the database community, there are still many critical issues to be resolved with respect to conducting advanced analysis on uncertain data. In this paper, we study the execution of the probabilistic skyline query over uncertain data streams. We propose a novel sliding window skyline model where an uncertain tuple may take the probability to be in the skyline at a certain timestamp t. Formally, a Wp-Skyline(p, t) contains all the tuples whose probabilities of becoming skylines are at least p at timestamp t. However, in the stream environment, computing a probabilistic skyline on a large number of uncertain tuples within the sliding window is a daunting task in practice. In order to efficiently calculate Wp-Skyline, we propose an efficient and effective approach, namely the candidate list approach, which maintains lists of candidates that might become skylines in future sliding windows. We also propose algorithms that continuously monitor the newly incoming and expired data to maintain the skyline candidate set incrementally. To further reduce the computation cost of deciding whether or not a candidate tuple belongs to the skyline, we propose an enhanced refinement strategy that is based on a multi-dimensional indexing structure combined with a grouping-and-conquer strategy. To validate the effectiveness of our proposed approach, we conduct extensive experiments on both real and synthetic data sets and make comparisons with basic techniques. © 2011 Elsevier Inc. All rights reserved.


Wang X.,Huazhong University of Science and Technology | Liu B.,Huazhong University of Science and Technology | Wang Q.,Huazhong University of Science and Technology | Song W.,Huazhong University of Science and Technology | And 4 more authors.
Advanced Materials | Year: 2013

Highly flexible stacked and in-plane all-solid-state supercapacitors are fabricated on 3D hierarchical GeSe2 nanostructures with high performance, and, when configured as a self-powered photodetector nanosystem, can be used to power CdSe nanowire photodetectors. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Candelaria S.L.,University of Washington | Chen R.,Intel Corporation | Chen R.,Huazhong University of Science and Technology | Jeong Y.-H.,Pohang University of Science and Technology | Cao G.,University of Washington
Energy and Environmental Science | Year: 2012

Highly porous carbon cryogels with tunable pore structure and chemical composition were synthesized through controlled hydrolysis and polycondensation reactions using different chemicals as precursors and either NaOH or hexamine (C 6N 12N 4) as catalysts. Gelation was followed with freeze drying to preserve the highly porous structure during solvent removal and controlled pyrolysis of the organic hydrogels and subsequent optional activation was performed. In addition, two different approaches were taken to modify the surface chemistry of porous carbon to introduce nitrogen or nitrogen-boron, leading to different porous structures and surface chemistry, as well as electrochemical properties. These carbon cryogels have been characterized and studied for energy storage applications. Specifically, they have been investigated as electrodes for electric double layer supercapacitors, high energy and high power density lithium-ion batteries with vanadium pentoxide deposited inside the pores, porous media for natural gas (methane) storage at reduced pressure, and scaffolds for hydride nanocomposites for greatly improved hydrogen storage. The relationship between processing conditions, chemical composition, pore structure, and energy storage properties are discussed. © The Royal Society of Chemistry 2012.


Liu N.,Huazhong University of Science and Technology | Jiang Y.,Beihang University | Zhou Y.,CAS Beijing National Laboratory for Molecular | Xia F.,Huazhong University of Science and Technology | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

Pore me another one: Sub-nanomolar sequence-specific DNA detection and sub-micromolar small-molecule (ATP) detection was shown by way of self-assembly and disassembly of DNA superstructures within solid-state nanopores (see scheme). These DNA structures provide a built-in amplification mechanism to increase the signal strength and sensitivity. This sensor was also shown to work within complex mixtures, such as mammalian serum. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jiang Y.,Beihang University | Liu N.,Huazhong University of Science and Technology | Guo W.,CAS Beijing National Laboratory for Molecular | Xia F.,Huazhong University of Science and Technology | And 2 more authors.
Journal of the American Chemical Society | Year: 2012

Integrating biological components into artificial devices establishes an interface to understand and imitate the superior functionalities of the living systems. One challenge in developing biohybrid nanosystems mimicking the gating function of the biological ion channels is to enhance the gating efficiency of the man-made systems. Herein, we demonstrate a DNA supersandwich and ATP gated nanofluidic device that exhibits high ON-OFF ratios (up to 106) and a perfect electric seal at its closed state (∼Gω). The ON-OFF ratio is distinctly higher than existing chemically modified nanofluidic gating systems. The gigaohm seal is comparable with that required in ion channel electrophysiological recording and some lipid bilayer-coated nanopore sensors. The gating function is implemented by self-assembling DNA supersandwich structures into solid-state nanochannels (open-to-closed) and their disassembly through ATP-DNA binding interactions (closed-to-open). On the basis of the reversible and all-or-none electrochemical switching properties, we further achieve the IMPLICATION logic operations within the nanofluidic structures. The present biohybrid nanofluidic device translates molecular events into electrical signals and indicates a built-in signal amplification mechanism for future nanofluidic biosensing and modular DNA computing on solid-state substrates. © 2012 American Chemical Society.


Xiao J.,Huazhong University of Science and Technology | Xiao J.,Hong Kong University of Science and Technology | Wan L.,Huazhong University of Science and Technology | Yang S.,Hong Kong University of Science and Technology | And 2 more authors.
Nano Letters | Year: 2014

We report on the development of highly conductive NiCo2S 4 single crystalline nanotube arrays grown on a flexible carbon fiber paper (CFP), which can serve not only as a good pseudocapacitive material but also as a three-dimensional (3D) conductive scaffold for loading additional electroactive materials. The resulting pseudocapacitive electrode is found to be superior to that based on the sibling NiCo2O4 nanorod arrays, which are currently used in supercapacitor research due to the much higher electrical conductivity of NiCo2S4. A series of electroactive metal oxide materials, including CoxNi 1-x(OH)2, MnO2, and FeOOH, were deposited on the NiCo2S4 nanotube arrays by facile electrodeposition and their pseudocapacitive properties were explored. Remarkably, the as-formed CoxNi1-x(OH)2/NiCo2S4 nanotube array electrodes showed the highest discharge areal capacitance (2.86 F cm-2 at 4 mA cm-2), good rate capability (still 2.41 F cm-2 at 20 mA cm-2), and excellent cycling stability (∼4% loss after the repetitive 2000 cycles at a charge-discharge current density of 10 mA cm-2). © 2014 American Chemical Society.


Yan K.,Hong Kong University of Science and Technology | Chen W.,Hong Kong University of Science and Technology | Chen W.,Huazhong University of Science and Technology | Yang S.,Hong Kong University of Science and Technology
Journal of Physical Chemistry C | Year: 2013

We have significantly improved open circuit voltage and fill factor with a Pt counter electrode of quasi-solid state quantum dot sensitized solar cells (QDSSCs) by achieving compact coverage of QDs on a TiO2 matrix through a linker seeding chemical bath deposition process, leading to 4.23% power conversion efficiency, nearly two times that with conventionally deposited control photoanode. The distinguishing characteristic of our linker seeding synthesis is that it does not rely on surface adsorption of precursor ions directly on TiO2 (TiO2∼Cdx) but rather nucleates special ionic seeds on a compact linker layer (TiO2-COORS- Cdx), thereby resulting in a full and even coverage of QDs on the TiO2 surface in large area. We have shown that the compact coverage not only helps to suppress recombination from electrolyte but also gives rise to better charge transport through the QD layer. This linker seeding chemical bath deposition method is general and expected to reinforce the hope of quasi-solid state QDSSCs as a strong competitor of dye-sensitized solar cells after further optimization and development. © 2012 American Chemical Society.


Guo Z.,Huazhong University of Science and Technology | Xu K.,Hong Kong University of Science and Technology | Wang R.,Hong Kong University of Science and Technology
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

Based on the Boltzmann-BGK (Bhatnagar-Gross-Krook) equation, in this paper a discrete unified gas kinetic scheme (DUGKS) is developed for low-speed isothermal flows. The DUGKS is a finite-volume scheme with the discretization of particle velocity space. After the introduction of two auxiliary distribution functions with the inclusion of collision effect, the DUGKS becomes a fully explicit scheme for the update of distribution function. Furthermore, the scheme is an asymptotic preserving method, where the time step is only determined by the Courant-Friedricks-Lewy condition in the continuum limit. Numerical results demonstrate that accurate solutions in both continuum and rarefied flow regimes can be obtained from the current DUGKS. The comparison between the DUGKS and the well-defined lattice Boltzmann equation method (D2Q9) is presented as well. © 2013 American Physical Society.


Ding F.,First Peoples Hospital of Jingmen | Shao Z.-W.,Huazhong University of Science and Technology | Xiong L.-M.,Huazhong University of Science and Technology
Apoptosis | Year: 2013

Degeneration of intervertebral disc (IVD) is mainly a chronic process of excessive destruction of the extracellular matrix (ECM), and also is thought to be the primary cause of low back pain. Presently, however, the underlying mechanism of IVD degeneration is still not elucidated. Cellular loss from cell death has been believed to contribute to the degradation of ECM and plays an important role in the process of IVD degeneration, but the mechanisms of cell death in degenerated IVD remain unclear. Apoptosis, a very important type of IVD cell death, has been considered to play a crucial role in the process of degeneration. Autophagy, a non-apoptosis death type of programmed cell death, has been considered extensively involved in many pathological and physiological processes, including the degenerative diseases. Thus, the research on cell death in IVD degeneration has become a new focus recently. In this review, by analyzing the available literature pertaining to cell death in IVD and discussing the inducing factors of IVD degeneration, NP cells and ECM in IVD degeneration, apoptotic signal transduction pathways involved in IVD cell death, the relationship of cell death with IVD degeneration and potential therapeutic strategy for IVD degeneration by regulating cell death, we conclude that different stimuli induce cell death in IVD via various signal transduction pathways, and that cell death may play a key role in the degenerative process of IVD. Regulation of cell death could be a potential and attractive therapeutic strategy for IVD degeneration. © 2013 Springer Science+Business Media New York.


Li K.,Huazhong University of Science and Technology | Schneider M.,University of Marburg
Journal of biomedical optics | Year: 2014

With ever-increasing applications of nanoscale materials in the biomedical field, the impact of nanoparticle size on cellular uptake efficiency, dynamics, and mechanism has attracted numerous interests but still leaves many open questions. A combined "multiphoton imaging-UV/Vis spectroscopic analysis" method was applied for the first time for quantitative visualization and evaluation of the cellular uptake process of different-sized (15-, 30-, 50-, and 80-nm) gold nanoparticles (AuNPs). Quantitative analysis of the size effect on cellular uptake behavior of AuNPs from a stack of three-dimensional multiphoton laser scanning microscopy images is obtained. The technique allows for differentiating AuNPs present in external and internal subcellular components, giving detailed information for elucidating cellular uptake dynamics without particle labeling. The data show that the internalization extent of AuNPs is highly dependent on particles' sizes and incubation time. Due to sedimentation, 50- and 80-nm AuNPs are taken up to a greater extent than 15- and 30-nm particles after exposure for 24 h. However, the smaller particles' uptake velocity is significantly faster in the first 10 h, indicating a disparity in uptake kinetics for different-sized AuNPs. The finding from this study will improve our understanding of the cellular uptake mechanisms of different-sized nanoparticles and has great implications in developing AuNP-based drug carriers with various sizes for different purposes.


Patent
Huazhong University of Science, Technology and China Changjiang National Shipping Group Motor Factory | Date: 2011-01-05

The invention disclose a type of winding rotator brushless double feed motor. This invention falls into motor technology field. The AC brushless double feed motors rotator is equipped with two sets of three phase windings whose number of pole pairs is p1 and p2; the rotator is in manner of multiphase winding, number of pole pairs is P1 and P2, and rotator is of multiphase coil windings, number of phases m is: m = (p_(1) + p_(2)) / m in which , m=1, when p_(1)+p_(2) is odd; ; m=2, when p_(1)+p_(2) is even, , rotor slots are distributed around air gaps, the number of slots Z is : Z = n(p_(1) + p_(2)) in which , n is a positive integer , coil of rotator windings is in structure of multi turn, number of coils of each phase is nm distance between each coil is even, but the number of turns of each coil is different, when number of phase winding coils is nm all coils of phase windings will be short circuit connected after then are connected in series. The advantage of this invention lies in that, not only span of winding coils can be changed flexibly, the number of turns of each coil is different, in order to remove higher-order harmonics as possibly as.


Patent
Huazhong University of Science, Technology and China Changjiang National Shipping Group Motor Factory | Date: 2011-03-30

This invention publishes a type of excitation control system structure and control method for ship diesel engine brushless double feed shaft-driven generator. The excitation control structure of ship brushless double feed shaft-driven generator includes contactor, step-up transformer, rectification feed unit, DC compensation unit, inverter unit, control panel, excitation controller, AB phase voltage, CA phase voltage sensor, BC phase voltage sensor; based on the control method for control system structure, initial excitation, constant-voltage control, constant frequency control, undervoltae control and overvoltage protection for ship brushless double feed shaft-driven generator can be realized.


Lu X.,Huazhong University of Science and Technology | Lu X.,University of Tsukuba | Akasaka T.,Huazhong University of Science and Technology | Akasaka T.,University of Tsukuba | And 2 more authors.
Accounts of Chemical Research | Year: 2013

Endohedral metallofullerenes (EMFs) are hybrid molecules with different metallic species encapsulated inside the fullerene cages. In addition to conventional EMFs that contain only metal ions, researchers have constructed novel compounds that encapsulate metallic clusters of nitride, carbide, oxide, cyanide, and sulfide. Among these structures, carbide cluster metallofullerenes (CCMFs) are unique because their synthesis requires only graphite and the metal source. As a result the molecular structures of CCMFs are particularly difficult to characterize. Two carbon atoms are encapsulated inside the cage, but they do not participate in constructing the cage framework. Recent X-ray crystallographic studies of EMFs have allowed researchers to unambiguously identify CCMFs (MxC2@C2n). Previously most of these structures had been described as conventional EMFs Mx@C 2n+2. Most of these species are scandium-containing compounds such as Sc3C2@Ih(7)-C80 [not Sc 3@C3v(7)-C82], Sc2C 2@C2v(5)-C80 [not Sc2@C 82], Sc2C2@Cs(6)-C82 [not Sc2@Cs(10)-C84], Sc2C 2@C2v(9)-C82 [not Sc2@C 2v(17)-C84], Sc2C2@C 3v(8)-C82 [not Sc2@D2d(23)-C 84], and Sc2C2@D2d(23)-C 84 [not Sc2@C86]. Additional examples of CCMFs include Gd2C2@D3(85)-C92, Sc 2C2@C2v(6073)-C68, Ti 2C2@D3h(5)-C78, M2C 2@C3v(8)-C82, M2C2@C s(6)-C82 (M = Y, Er, etc.), Y2C 2@C84, Y2C2@D3(85)-C 92, Y2C2@D5(450)-C100, and Lu3C2@D2(35)-C88. The existence of so many CCMF species reminds us that the symbol '@' (which denotes the encapsulation status of EMFs) should be used with caution with species whose molecular structures have not been determined unambiguously.This Account presents a detailed summary of all aspects of CCMFs, including historically erroneous assignments and corrected structural characterizations, along with their intrinsic properties such as electrochemical and chemical properties. We emphasize structural issues, features that are fundamental for understanding their intrinsic properties. Finally, we discuss the formation mechanism and possible origin of cluster EMFs, not just CCMFs. © 2013 American Chemical Society.


News Article | November 14, 2016
Site: phys.org

The widespread use of cloud computing and Big Data comes hand-in-hand with the need for data storage, computing and networking facilities capable of ensuring a reliable and secure infrastructure for information systems to operate on. Due to the high energy demands of data centers and their corresponding networks, resource consumption has become a challenging concern that may hinder further development of network and data center systems. At present, typical resource utilization is about 5% to 25% according to some statistics. Future data center design, management, and applications must tackle the need for sufficient energy efficiency if their growth is not to be associated to environmental damage. In view of the above scenario, an international cooperation ICT research project has been established and is supported by the National Natural Science Foundation of China. The objective of this research is to reduce currently high and inefficient energy consumption on data centers from the perspective of job scheduling and resource management. The international research team already at work includes scientists from the Chinese Academy of Sciences and Huazhong University of Science and Technology in China, IMDEA Networks Institute in Spain, and Temple University as well as University of California, Riverside in the USA. Initial investigations made on the characteristics of power consumption by data center servers have yielded results to be applied to the energy-efficient technical design of data centers. The team has also developed routing schemes for data center networks that increase energy savings. Furthermore, a carbon-aware online control model for geographically distributed datacenters is being developed, where electricity costs, service level agreement (SLA) requirements, and an emission reduction budget are taken into consideration. This internationally coordinated research project will last 5 years. Its findings and developed techniques aim to achieve a double objective: make data centers greener, thanks to reduced energy consumption and lesser CO2 emissions, whilst maintaining satisfactory service levels. The team of researchers hopes that, thanks to this work, we can all continue to enjoy the convenience of using data centers, without diminishing our enjoyment of a clean and cared for environment. Explore further: Data centers continue to proliferate while their energy use plateaus More information: Biyu Zhou, Fa Zhang, Lin Wang, Chenying Hou, Antonio Fernandez Anta, Athanasios Vasilakos, Youshi Wang, Jie Wu, Zhiyong Liu. "HDEER: A Distributed Routing Scheme for Energy Efficient Networking". IEEE Journal on Selected Areas in Communications (JSAC), 34(5):1-1, 2016. Zhi Zhou, Fangming Liu, Ruolan Zou, Jiangchuan Liu, Hong Xu, Hai Jin, "Carbon-aware Online Control of Geo-Distributed Cloud Services", IEEE Transactions on Parallel and Distributed Systems, Volume 27, Issue 9, September 2016. Dawei Li, Jie Wu, Zhiyong Liu, Fa Zhang. "Towards the Tradeoffs in Designing Data Center Network Architectures". IEEE Transactions on Parallel and Distributed Systems, (in press).


Ouyang M.,Rice University | Ouyang M.,Huazhong University of Science and Technology | Duenas-Osorio L.,Rice University | Min X.,Rice University
Structural Safety | Year: 2012

This paper proposes a new multi-stage framework to analyze infrastructure resilience. For each stage, a series of resilience-based improvement strategies are highlighted and appropriate correlates of resilience identified, to then be combined for establishing an expected annual resilience metric adequate for both single hazards and concurrent multiple hazard types. Taking the power transmission grid in Harris County, Texas, USA, as a case study, this paper compares an original power grid model with several hypothetical resilience-improved models to quantify their effectiveness at different stages of their response evolution to random hazards and hurricane hazards. Results show that the expected annual resilience is mainly compromised by random hazards due to their higher frequency of occurrence relative to hurricane hazards. In addition, under limited resources, recovery sequences play a crucial role in resilience improvement, while under sufficient availability of resources, deploying redundancy, hardening critical components and ensuring rapid recovery are all effective responses regardless of their ordering. The expected annual resilience of the power grid with all three stage improvements increases 0.034% compared to the original grid. Although the improvement is small in absolute magnitude due to the high reliability of real power grids, it can still save millions of dollars per year as assessed by energy experts. This framework can provide insights to design, maintain, and retrofit resilient infrastructure systems in practice. © 2011 Elsevier Ltd.


Zhu G.-R.,Wuhan University of Technology | Tan S.-C.,University of Hong Kong | Chen Y.,Huazhong University of Science and Technology | Tse C.K.,Hong Kong Polytechnic University
IEEE Transactions on Power Electronics | Year: 2013

Fuel-cell power systems comprising single-phase dc/ac inverters draw low-frequency ac ripple currents at twice the output frequency from the fuel cell. Such a 100/120Hz ripple current may create instability in the fuel-cell system, lower its efficiency, and shorten the lifetime of a fuel cell stack. This paper presents a waveform control method that can mitigate such a low-frequency ripple current being drawn from the fuel cell while the fuel-cell system delivers ac power to the load through a differential inverter. This is possible because with the proposed solution, the pulsation component (cause of ac ripple current) of the output ac power will be supplied mainly by the two output capacitors of the differential inverter while the average dc output power is supplied by the fuel cell. Theoretical analysis, simulation, and experimental results are provided to explain the operation and showcase the performance of the approach. Results validate that the proposed solution can achieve significant mitigation of the current ripple as well as high-quality output voltage without extra hardware. Application of the solution is targeted at systems where current ripple mitigation is required, such as for the purpose of eliminating electrolytic capacitor in photovoltaic and LED systems. © 1986-2012 IEEE.


Ouyang M.,Huazhong University of Science and Technology | Duenas-Osorio L.,Rice University
Structural Safety | Year: 2014

Electric power systems are critical to economic prosperity, national security, public health and safety. However, in hurricane-prone areas, a severe storm may simultaneously cause extensive component failures in a power system and lead to cascading failures within it and across other power-dependent utility systems. Hence, the hurricane resilience of power systems is crucial to ensure their rapid recovery and support the needs of the population in disaster areas. This paper introduces a probabilistic modeling approach for quantifying the hurricane resilience of contemporary electric power systems. This approach includes a hurricane hazard model, component fragility models, a power system performance model, and a system restoration model. These coupled four models enable quantifying hurricane resilience and estimating economic losses. Taking as an example the power system in Harris County, Texas, USA, along with real outage and restoration data after Hurricane Ike in 2008, the proposed resilience assessment model is calibrated and verified. In addition, several dimensions of resilience as well as the effectiveness of alternative strategies for resilience improvement are simulated and analyzed. Results show that among technical, organizational and social dimensions of resilience, the organizational resilience is the highest with a value of 99.964% (3.445 in a proposed logarithmic scale) while the social resilience is the lowest with a value of 99.760% (2.620 in the logarithmic scale). Although these values seem high in absolute terms due to the reliability of engineered systems, the consequences of departing from ideal resilience are still high as economic losses can add up to $83 million per year. © 2014 Elsevier Ltd.


Chen T.,Zhejiang GongShang University | Xiao R.,Huazhong University of Science and Technology
The Scientific World Journal | Year: 2014

Artificial bee colony (ABC) algorithm, inspired by the intelligent foraging behavior of honey bees, was proposed by Karaboga. It has been shown to be superior to some conventional intelligent algorithms such as genetic algorithm (GA), artificial colony optimization (ACO), and particle swarm optimization (PSO). However, the ABC still has some limitations. For example, ABC can easily get trapped in the local optimum when handing in functions that have a narrow curving valley, a high eccentric ellipse, or complex multimodal functions. As a result, we proposed an enhanced ABC algorithm called EABC by introducing self-adaptive searching strategy and artificial immune network operators to improve the exploitation and exploration. The simulation results tested on a suite of unimodal or multimodal benchmark functions illustrate that the EABC algorithm outperforms ACO, PSO, and the basic ABC in most of the experiments. © 2014 Tinggui Chen and Renbin Xiao.


Zhang X.,Huazhong University of Science and Technology | Zhang X.,Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment | Zhang H.,Wuhan Textile University
International Journal of Mechanical Sciences | Year: 2013

With appropriate design, functionally graded metallic foam can show definitely better properties than homogeneous counterpart due to its better designability. In the present work, functionally graded aluminum foam blocks subjected to ball impact are investigated numerically by using nonlinear finite element code. Blocks with different density gradient distributions, various geometric parameters and under different impact velocities are analyzed. The block with linear decreasing density gradient is found to possess excellent performance in energy absorption and outperform blocks with other density distributions under middle to high speed impact. To obtain the optimal design of the functionally graded foam block, a structural optimization problem with the objective of maximizing the crush force efficiency is solved by response surface method (RSM). The thickness and density of each layer are selected as design variables and it is interesting to find that the optimum design shows gradually decreasing density distribution. © 2013 Elsevier Ltd.


Zang H.,University of Tennessee at Knoxville | Liang Y.,University of Chicago | Yu L.,University of Chicago | Hu B.,University of Tennessee at Knoxville | Hu B.,Huazhong University of Science and Technology
Advanced Energy Materials | Year: 2011

This article reports experimental studies on internal charge dissociation, transport, and collection by using magnetic fi eld effects of photocurrent (MFE PC) and light-assisted dielectric response (LADR) in highly-efficient organic solar cells based on photovoltaic polymer PTB2 and PTB4 with intra-molecular "donor-acceptor" interaction. The MFE PC at low-field (<150 mT ) indicates that intra-molecular "donor-acceptor" interaction generates charge dissociation in un-doped PTB2 and PTB4 fi lms, which is similar to that in lightly doped P3HT (Poly(3-hexylthiophene)) with 5 wt% PCBM (1-(3-methyloxycarbonyl)- propyl-1-phenyl (6,6) C 61). After PTB2 and PTB4 are mixed with PCBM to form bulk-heterojunctions, the MFE PC at high-fi eld (>150 mT ) reveals that the charge-transfer complexes formed at PTB2:PCBM and PTB4:PCBM interfaces have much lower binding energies due to stronger electron-withdrawing abilities, as compared to the P3HT:PCBM device, towards the generation of photocurrent. Furthermore, the light-assisted dielectric response: LADR indicates that the PTB2:PCBM and PTB4:PCBM solar cells exhibit larger capacitances relative to P3HT:PCBM device under photoexcitation. This refl ects that the PTB2:PCBM and PTB4:PCBM bulk heterojunctions have more effective charge transport and collection than the P3HT:PCBM counterpart. As a result, our experimental results indicate that intra-molecular "donor-acceptor" interaction plays an important role to enhance charge dissociation, transport, and collection in bulk-heterojunction organic solar cells. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gong Y.-G.,Huazhong University of Science and Technology | Gong Y.-G.,CAS Institute of Theoretical Physics
Communications in Theoretical Physics | Year: 2013

We argue that more cosmological solutions in massive gravity can be obtained if the metric tensor and the tensor Σμν defined by Stückelberg fields take the homogeneous and isotropic form. The standard cosmology with matter and radiation dominations in the past can be recovered and ΛCDM model is easily obtained. The dynamical evolution of the universe is modified at very early times. © 2013 Chinese Physical Society and IOP Publishing Ltd.


Shen J.,CAS Shanghai Institutes for Biological Sciences | Li Y.,Huazhong University of Science and Technology | Li Y.,Hubei University | Gu H.,Hubei University | And 2 more authors.
Chemical Reviews | Year: 2014

The detection of proteins, nucleic acids, small molecules, and ions is of great importance in both the study of their fundamental functions and the development of molecular diagnostics. These biological molecules and ions not only are involved in the construction of living organisms, but also carry out most biological functions, including storage and transmission of genetic information, regulating biochemical activities and reactions, storing and transporting energy, and providing mechanical support. With the development of biotechnology, different recognition molecules, such as antibodies, oligonucleotide sequences, and aptamers, have been applied to specifically and selectively recognize protein, DNA, small molecules, and ions. At the same time, the feasibility of modifying the antibody with different signaling markers, such as fluorescein, radionuclides, enzymes, and redox tags, in turn allows for a broader variety of readouts in a sandwich-structured assay.


Ma J.,Huazhong University of Science and Technology | Zhao J.,Carnegie Mellon University | Tian J.,Huazhong University of Science and Technology | Yuille A.L.,University of California at Los Angeles | Tu Z.,University of California at San Diego
IEEE Transactions on Image Processing | Year: 2014

In this paper, we propose an efficient algorithm, called vector field consensus, for establishing robust point correspondences between two sets of points. Our algorithm starts by creating a set of putative correspondences which can contain a very large number of false correspondences, or outliers, in addition to a limited number of true correspondences (inliers). Next, we solve for correspondence by interpolating a vector field between the two point sets, which involves estimating a consensus of inlier points whose matching follows a nonparametric geometrical constraint. We formulate this a maximum a posteriori (MAP) estimation of a Bayesian model with hidden/latent variables indicating whether matches in the putative set are outliers or inliers. We impose nonparametric geometrical constraints on the correspondence, as a prior distribution, using Tikhonov regularizers in a reproducing kernel Hilbert space. MAP estimation is performed by the EM algorithm which by also estimating the variance of the prior model (initialized to a large value) is able to obtain good estimates very quickly (e.g., avoiding many of the local minima inherent in this formulation). We illustrate this method on data sets in 2D and 3D and demonstrate that it is robust to a very large number of outliers (even up to 90%). We also show that in the special case where there is an underlying parametric geometrical model (e.g., the epipolar line constraint) that we obtain better results than standard alternatives like RANSAC if a large number of outliers are present. This suggests a two-stage strategy, where we use our nonparametric model to reduce the size of the putative set and then apply a parametric variant of our approach to estimate the geometric parameters. Our algorithm is computationally efficient and we provide code for others to use it. In addition, our approach is general and can be applied to other problems, such as learning with a badly corrupted training data set. © 1992-2012 IEEE.


Zhang X.,Huazhong University of Science and Technology | Zhang X.,Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment | Zhang H.,Wuhan Textile University
International Journal of Impact Engineering | Year: 2014

Multi-cell columns are highly efficient energy absorbing components under axial compression. However, the experimental investigations and theoretical analyses for the deformation modes and mechanisms of them are quite few. In this paper, the axial crushing of circular multi-cell columns are studied experimentally, numerically and theoretically. Circular multi-cell columns with different sections are axially compressed quasi-statically and numerical analyses are carried out by nonlinear finite element code LS-DYNA to simulate the experiments. The deformation modes of the multi-cell columns are described and the energy absorption properties of them are compared with those of simple circular tube. Theoretical models based on the constituent element method are then proposed to predict the crush resistance of circular multi-cell specimens. The theoretical predictions are found to be in a good agreement with the experimental and numerical results. © 2013 Elsevier Ltd. All rights reserved.


Huang J.,Huazhong University of Science and Technology | Shi H.,Wuhan Textile University
IEEE Transactions on Power Electronics | Year: 2014

High common-mode voltage (CMV) of an output will be produced in the conventional sinusoidal pulse width modulation three-phase inverter. Although the carrier phase-shift method can be used to reduce the peaks of CMV, it has the best suppression effect only when the SPWM modulation index is no more than 2/3. This letter presents a new scheme of carrier peak position modulation to break the limitation of modulation index. In this scheme, the peak positions of the triangular carriers are delayed or advanced to avoid the zero state. Thus, the peaks of CMV will be reduced under any modulation index. The feasibility and validity of this scheme are verified through the experiments. © 1986-2012 IEEE.


Gao Q.,Huazhong University of Science and Technology | Gong Y.,Huazhong University of Science and Technology | Gong Y.,CAS Institute of Theoretical Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The detection of B-mode power spectrum by the BICEP2 collaboration constrains the tensor-to-scalar ratio r=0.20-0.05+0.07 for the lensed-ΛCDM model. The consistency of this big value with the Planck results requires a large running of the spectral index. The large values of the tensor-to-scalar ratio and the running of the spectral index put a challenge to single field inflation. For the chaotic inflation, the larger the value of the tensor-to-scalar ratio is, the smaller the value of the running of the spectral index is. For the natural inflation, the absolute value of the running of the spectral index has an upper limit. © 2014 The Authors.


Wang X.,Chinese Academy of Sciences | Wang X.,Huazhong University of Science and Technology | Lu X.,Sun Yat Sen University | Liu B.,Chinese Academy of Sciences | And 4 more authors.
Advanced Materials | Year: 2014

Flexible energy-storage devices are attracting increasing attention as they show unique promising advantages, such as flexibility, shape diversity, light weight, and so on; these properties enable applications in portable, flexible, and even wearable electronic devices, including soft electronic products, roll-up displays, and wearable devices. Consequently, considerable effort has been made in recent years to fulfill the requirements of future flexible energy-storage devices, and much progress has been witnessed. This review describes the most recent advances in flexible energy-storage devices, including flexible lithium-ion batteries and flexible supercapacitors. The latest successful examples in flexible lithium-ion batteries and their technological innovations and challenges are reviewed first. This is followed by a detailed overview of the recent progress in flexible supercapacitors based on carbon materials and a number of composites and flexible micro-supercapacitors. Some of the latest achievements regarding interesting integrated energy-storage systems are also reviewed. Further research direction is also proposed to surpass existing technological bottle-necks and realize idealized flexible energy-storage devices. Flexible energy-storage devices are indispensable to the development of flexible electronics. This review surveys recent achievements, focusing on flexible lithium-ion batteries and flexible supercapacitors combined with integrated energy-storage systems. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gong Y.,Huazhong University of Science and Technology | Gong Y.,CAS Institute of Theoretical Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

We discuss the general dynamical behaviors of quintessence field, in particular, the general conditions for tracking and thawing solutions are discussed. We explain what the tracking solutions mean and in what sense the results depend on the initial conditions. Based on the definition of tracking solution, we give a simple explanation on the existence of a general relation between wφ and Ωφ which is independent of the initial conditions for the tracking solution. A more general tracker theorem which requires large initial values of the roll parameter is then proposed. To get thawing solutions, the initial value of the roll parameter needs to be small. The power-law and pseudo-Nambu Goldstone boson potentials are used to discuss the tracking and thawing solutions. A more general wφ-Ωφ relation is derived for the thawing solutions. © 2014 The Authors.


Bai X.,Huazhong University of Science and Technology | Yang X.,Temple University | Latecki L.J.,Temple University | Liu W.,Huazhong University of Science and Technology | Tu Z.,University of California at Los Angeles
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2010

Shape similarity and shape retrieval are very important topics in computer vision. The recent progress in this domain has been mostly driven by designing smart shape descriptors for providing better similarity measure between pairs of shapes. In this paper, we provide a new perspective to this problem by considering the existing shapes as a group, and study their similarity measures to the query shape in a graph structure. Our method is general and can be built on top of any existing shape similarity measure. For a given similarity measure, a new similarity is learned through graph transduction. The new similarity is learned iteratively so that the neighbors of a given shape influence its final similarity to the query. The basic idea here is related to PageRank ranking, which forms a foundation of Google Web search. The presented experimental results demonstrate that the proposed approach yields significant improvements over the state-of-art shape matching algorithms. We obtained a retrieval rate of 91.61 percent on the MPEG-7 data set, which is the highest ever reported in the literature. Moreover, the learned similarity by the proposed method also achieves promising improvements on both shape classification and shape clustering. © 2006 IEEE.


Wang W.,Tsinghua University | Huang J.,Nanyang Technological University | Wen C.,Nanyang Technological University | Fan H.,Huazhong University of Science and Technology
Automatica | Year: 2014

In this paper, we investigate the output consensus problem of tracking a desired trajectory for a class of systems consisting of multiple nonlinear subsystems with intrinsic mismatched unknown parameters. The subsystems are allowed to have non-identical dynamics, whereas with similar structures and the same yet arbitrary system order. And the communication status among the subsystems can be represented by a directed graph. Different from the traditional centralized tracking control problem, only a subset of the subsystems can obtain the desired trajectory information directly. A distributed adaptive control approach based on backstepping technique is proposed. By introducing the estimates to account for the parametric uncertainties of the desired trajectory and its neighbors' dynamics into the local controller of each subsystem, information exchanges of online parameter estimates and local synchronization errors among linked subsystems can be avoided. It is proved that the boundedness of all closed-loop signals and the asymptotically consensus tracking for all the subsystems' outputs are ensured. A numerical example is illustrated to show the effectiveness of the proposed control scheme. Moreover, the design strategy is successfully applied to solve a formation control problem for multiple nonholonomic mobile robots. © 2014 Elsevier Ltd. All rights reserved.


Zhou J.,Huazhong University of Science and Technology | Huang K.,Huazhong University of Science and Technology | Lei X.G.,Cornell University
Free Radical Biology and Medicine | Year: 2013

Whereas selenium was found to act as an insulin mimic and to be antidiabetic in earlier studies, recent animal experiments and human trials have shown an unexpected risk of prolonged high Se intake in potentiating insulin resistance and type 2 diabetes. Elevating dietary Se intake (0.4 to 3.0 mg/kg of diet) above the nutrient requirements, similar to overproduction of selenoproteins, led to insulin resistance and/or diabetes-like phenotypes in mice, rats, and pigs. Although its diabetogenic mechanism remains unclear, high Se intake elevated activity or production of selenoproteins including GPx1, MsrB1, SelS, and SelP. This upregulation diminished intracellular reactive oxygen species and then dysregulated key regulators of β cells and insulin synthesis and secretion, leading to chronic hyperinsulinemia. Overscavenging intracellular H2O2 also attenuated oxidative inhibition of protein tyrosine phosphatases and suppressed insulin signaling. High Se intake might affect expression and/or function of key regulators of glycolysis, gluconeogenesis, and lipogenesis. Future research is needed to find out if certain forms of Se metabolites in addition to selenoproteins and if mechanisms other than intracellular redox control mediate the diabetogenic effects of high Se intake. Furthermore, a potential interactive role of high Se intake in the interphase of carcinogenesis and diabetogenesis should be explored to make optimal use of Se in human nutrition and health. © 2013 Elsevier Inc.


Zhang X.,Huazhong University of Science and Technology | Zhang X.,Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment | Zhang H.,Wuhan Textile University
International Journal of Impact Engineering | Year: 2012

Honeycomb cellular structures and multi-cell prismatic columns are highly efficient and effective energy dissipating components and are widely used in the crashworthiness design of vehicles. Due to the complex features during large plastic deformation, only few special sections have been theoretical modeled for their energy absorption capacity under axial compression. In this paper, based on a simplified FE model, the energy absorption characteristics of angle elements with three panels are investigated by using the non-linear finite element code LS-DYNA. Theoretical models are proposed to predict the crush resistance of three-panel angle elements with different angles. Numerical results show that the proposed theoretical model can predict the energy absorption of these angle elements with good accuracy. © 2012 Elsevier Ltd. All rights reserved.


Yuan L.,Huazhong University of Science and Technology | Yao B.,Huazhong University of Science and Technology | Yao B.,Wuhan University of Technology | Hu B.,Huazhong University of Science and Technology | And 3 more authors.
Energy and Environmental Science | Year: 2013

Highly conductive paper was fabricated through polypyrrole (PPy) coating on common printing paper by a simple and low-cost "soak and polymerization" method. The as-fabricated porous, flexible and conductive paper shows a high electrical conductivity of 15 S cm-1 and a low sheet resistance of 4.5 Ω sq-1. Flexible solid-state supercapacitors assembled with PPy/paper composite electrodes had an average weight of 55 mg and an areal capacitance of 0.42 F cm-2, indicating a high energy density of 1 mW h cm-3 at a power density of 0.27 W cm-3 normalized to the volume of the whole cell (electrode, electrolyte, and separator). Furthermore, this method could be easily scaled up to large-scale fabrication of conductive paper and opened up new opportunities for flexible energy storage. This journal is © The Royal Society of Chemistry 2013.


Ma J.,Huazhong University of Science and Technology | Ma J.,University of California at Los Angeles | Zhao J.,Robotics Institute | Tian J.,Huazhong University of Science and Technology | And 2 more authors.
Proceedings of the IEEE Computer Society Conference on Computer Vision and Pattern Recognition | Year: 2013

We present a new point matching algorithm for robust nonrigid registration. The method iteratively recovers the point correspondence and estimates the transformation between two point sets. In the first step of the iteration, feature descriptors such as shape context are used to establish rough correspondence. In the second step, we estimate the transformation using a robust estimator called L-2E. This is the main novelty of our approach and it enables us to deal with the noise and outliers which arise in the correspondence step. The transformation is specified in a functional space, more specifically a reproducing kernel Hilbert space. We apply our method to nonrigid sparse image feature correspondence on 2D images and 3D surfaces. Our results quantitatively show that our approach outperforms state-of-the-art methods, particularly when there are a large number of outliers. Moreover, our method of robustly estimating transformations from correspondences is general and has many other applications. © 2013 IEEE.


Hu B.,Huazhong University of Science and Technology | Chen W.,Wuhan University of Technology | Zhou J.,Huazhong University of Science and Technology
Sensors and Actuators, B: Chemical | Year: 2013

In recent years, the rapid development of flexible electronic devices indicates their attractive perspective in various applications where flexibility, space savings, or production constraints limit the serviceability of rigid circuit boards or hand wiring. While sensors, as the important components in such multifunctional devices, also required to be flexible and robust for integration. In addition, with the emergency of smart sensor networks, low cost, low energy consumption and easy-fabrication sensors with various functions are demanded urgently. Compared with the flexible organic electronic sensors, inorganic nanomaterials based sensors with long life-time and the high carrier mobility have been attracting the interest of researchers, and the tremendous progress has been made for developing the flexible, high-performance inorganic materials based sensors. In this article, we review the recent advancements of some important inorganic materials in various sensing applications, including carbon material and some transition metal oxides. © 2012 Elsevier B.V. All rights reserved.


Peng H.,Huazhong University of Science and Technology | Peng H.,Inner Mongolia Power Exploration and Design Institute | Liu F.,Huazhong University of Science and Technology | Yang X.,Inner Mongolia Power Exploration and Design Institute
Renewable Energy | Year: 2013

Two different prediction methods are investigated for short term wind power prediction of a wind farm in this paper. The adopted strategies are individual artificial neural network (ANN) and hybrid strategy based on the physical and the statistical methods. The performance of two prediction methods is comprehensively compared. The calculated results show that the individual ANN prediction method can yield the prediction results quickly. The prediction accuracy is low and the root mean squared error (RMSE) is 10.67%. By contrast the hybrid prediction method operates costly and slowly. However, the prediction accuracy is high and the RMSE is 2.01%, less than 1/5 of that by individual ANN method. Meanwhile, it is found that the errors of the prediction have some relation with the wind speeds. The prediction errors are small when the wind speeds lower than 5 m/s or higher than 15 m/s. The reasons for such phenomena are also investigated. © 2012 Elsevier Ltd.


Wu X.-F.,Chinese Academy of Sciences | Wu X.-F.,Nanjing University | Hou S.-J.,Xiamen University | Lei W.-H.,Huazhong University of Science and Technology
Astrophysical Journal Letters | Year: 2013

A particularly interesting discovery in observations of GRB 121027A is that of a giant X-ray bump detected by the Swift/X-Ray Telescope. The X-ray afterglow re-brightens sharply at ≃103 s after the trigger by more than two orders of magnitude in less than 200 s. This X-ray bump lasts for more than 104 s. It is quite different from typical X-ray flares. In this Letter we propose a fall-back accretion model to interpret this X-ray bump within the context of the collapse of a massive star for a long-duration gamma-ray burst. The required fall-back radius of ≃3.5 × 10 10 cm and mass of ≃0.9-2.6 M imply that a significant part of the helium envelope should survive through the mass loss during the last stage of the massive progenitor of GRB 121027A. © 2013. The American Astronomical Society. All rights reserved..


Zhang X.,Huazhong University of Science and Technology | Zhang X.,Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment | Zhang H.,Wuhan Textile University
Thin-Walled Structures | Year: 2013

Multi-cell metal columns were found to be much more efficient in energy absorption than single-cell columns under axial compression. However, the experimental investigations and theoretical analyses of them are relatively few. In this paper, the quasi-static axial compression tests are carried out for multi-cell columns with different sections. The significant advantage of multi-cell sections over single cell in energy absorption efficiency is investigated and validated. Numerical simulations are also conducted to simulate the compression tests and the numerical results show a very good agreement with experiment. Theoretial analyses based on constitutive element method are proposed to predict the crush resistance of multi-cell columns and the theoretical predictions compare very well with the experimental and numerical results. © 2013 Elsevier Ltd.


Zhang X.,Huazhong University of Science and Technology | Zhang X.,Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment | Zhang H.,Wuhan Textile University
International Journal of Impact Engineering | Year: 2013

The present work is aimed at finding the maximum energy absorption efficiency of plates in thin-walled structures under compression. In thin-walled structures, the plates are connected with different angles and by different edge connectivity. The influences of these two major factors on the crush resistance of structures are investigated numerically by nonlinear finite element code. Two extreme modes: uniform mode and opposite mode are defined for the angle elements with different edge connectivity. The energy absorption characteristics of these two modes are investigated and a theoretical model is established to predict the energy absorption capacity of elements deforming in uniform mode. Experimental tests of multi-cell columns are conducted to validate the numerical analyses and theoretical models for angle elements. The numerical simulations and theoretical predictions of the crush resistance of multi-cell columns show a very good agreement with the experimental results. © 2013 Elsevier Ltd. All rights reserved.


Tu Z.,University of California at Los Angeles | Bai X.,Huazhong University of Science and Technology
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2010

The notion of using context information for solving high-level vision and medical image segmentation problems has been increasingly realized in the field. However, how to learn an effective and efficient context model, together with an image appearance model, remains mostly unknown. The current literature using Markov Random Fields (MRFs) and Conditional Random Fields (CRFs) often involves specific algorithm design in which the modeling and computing stages are studied in isolation. In this paper, we propose a learning algorithm, auto-context. Given a set of training images and their corresponding label maps, we first learn a classifier on local image patches. The discriminative probability (or classification confidence) maps created by the learned classifier are then used as context information, in addition to the original image patches, to train a new classifier. The algorithm then iterates until convergence. Auto-context integrates low-level and context information by fusing a large number of low-level appearance features with context and implicit shape information. The resulting discriminative algorithm is general and easy to implement. Under nearly the same parameter settings in training, we apply the algorithm to three challenging vision applications: foreground/background segregation, human body configuration estimation, and scene region labeling. Moreover, context also plays a very important role in medical/brain images where the anatomical structures are mostly constrained to relatively fixed positions. With only some slight changes resulting from using 3D instead of 2D features, the auto-context algorithm applied to brain MRI image segmentation is shown to outperform state-of-the-art algorithms specifically designed for this domain. Furthermore, the scope of the proposed algorithm goes beyond image analysis and it has the potential to be used for a wide variety of problems for structured prediction problems. © 2006 IEEE.


Peng C.,Nanjing Normal University | Tian Y.-C.,Queensland University of Technology | Yue D.,Huazhong University of Science and Technology
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2011

This correspondence paper addresses the problem of output feedback stabilization of control systems in networked environments with quality-of-service (QoS) constraints. The problem is investigated in discrete-time state space using Lyapunov's stability theory and the linear inequality matrix technique. A new discrete-time modeling approach is developed to describe a networked control system (NCS) with parameter uncertainties and nonideal network QoS. It integrates a network-induced delay, packet dropout, and other network behaviors into a unified framework. With this modeling, an improved stability condition, which is dependent on the lower and upper bounds of the equivalent network-induced delay, is established for the NCS with norm-bounded parameter uncertainties. It is further extended for the output feedback stabilization of the NCS with nonideal QoS. Numerical examples are given to demonstrate the main results of the theoretical development. © 2006 IEEE.


Zuo F.,Huazhong University of Science and Technology | Gao Y.-H.,CAS Institute of Theoretical Physics
Journal of High Energy Physics | Year: 2014

Abstract: Recent lattice simulation has uncovered many interesting properties of SU(N) gauge theory at finite temperature. Especially, above the deconfinement phase transition all the thermodynamic quantities acquire significant quadratic contributions in inverse temperature. Such a term is also found to dominate the logarithm of the renormalized Polyakov loop. Using the Hawking-Page transition in Anti-de Sitter space as an example, we show how such contributions can be naturally generated in the holographic approach. © 2014, The Author(s).


Xu W.,Huazhong University of Science and Technology | Wang J.,Nankai University | Meng X.-H.,Nankai University | Meng X.-H.,CAS Institute of Theoretical Physics
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

We revisit the entropy product, entropy sum and other thermodynamic relations of charged and rotating black holes. Based on these relations, we derive the entropy (area) bound for both event horizon and Cauchy horizon. We establish these results for variant class of 4-dimensional charged and rotating black holes in Einstein(-Maxwell) gravity and higher derivative gravity. We also generalize the discussion to black holes with NUT charge. The validity of this formula, which seems to be universal for black holes with two horizons, gives further clue on the crucial role that the thermodynamic relations of multi-horizons play in black hole thermodynamics and understanding the entropy at the microscopic level. © 2015 The Authors.


Zuo F.,Huazhong University of Science and Technology | Gao Y.-H.,CAS Institute of Theoretical Physics
Nuclear Physics B | Year: 2016

Induced by the Hagedorn instability, weakly-coupled U(N) gauge theories on a compact manifold exhibit a confinement/deconfinement phase transition in the large-N limit. Recently we discover that the thermal entropy of a free theory on S3 gets reduced by a universal constant term, -N2/4, compared to that from completely deconfined colored states. This entropy deficit is due to the persistence of Gauss's law, and actually independent of the shape of the manifold. In this paper we show that this universal term can be identified as the topological entangle entropy both in the corresponding 4+1D bulk theory and the dimensionally reduced theory. First, entanglement entropy in the bulk theory contains the so-called "particle" contribution on the entangling surface, which naturally gives rise to an area-law term. The topological term results from the Gauss's constraint of these surface states. Secondly, the high-temperature limit also defines a dimensionally reduced theory. We calculate the geometric entropy in the reduced theory explicitly, and find that it is given by the same constant term after subtracting the leading term of O(β-1). The two procedures are then applied to the confining phase, by extending the temperature to the complex plane. Generalizing the recently proposed 2D modular description to an arbitrary matter content, we show the leading local term is missing and no topological term could be definitely isolated. For the special case of N=4 super Yang-Mills theory, the results obtained here are compared with that at strong coupling from the holographic derivation. © 2016 The Authors.


Liu J.,Huazhong University of Science and Technology | He M.,Huazhong University of Science and Technology | Zheng C.,Huazhong University of Science and Technology | Chang M.,Wuhan University of Technology
Proceedings of the Combustion Institute | Year: 2011

The installation of selective catalytic reduction (SCR) system for reduction of NOx can prompt the oxidation and removal of elemental mercury. Understanding the mechanism behind Hg oxidation via SCR catalysts will broaden the applicability of SCR system in Hg removal strategies. This research investigated the bindings of Hg0, HCl, HgCl and HgCl2 to the V2O5 (0 0 1) surface using density functional theory (DFT) method. The V2O5 (0 0 1) surface was represented by a periodic model, and different adsorption sites were considered. Adsorption energies and geometries of Hg0, HCl, HgCl and HgCl2 on the V2O5 surface were calculated. The results indicated that Hg0 adsorption on V2O5 surface is stronger than that of HCl. The adsorptions of HgCl and HgCl2 on V 2O5 surface are mainly chemisorption. The adsorption energy of HgCl on V2O5 surface is stronger than that of HgCl2, which means that HgCl-surface is an important intermediate for mercury oxidation. The chlorine species has a strong influence on mercury adsorption as well as mercury oxidation, which is compatible with the available experimental results. The oxidation pathway for V2O 5-catalyzed Hg oxidation by chlorine species was also presented. © 2010 The Combustion Institute. Published by Elsevier Inc. All rights reserved.


Xu Y.,Tsinghua University | Wang X.,Tsinghua University | Wang X.,Huazhong University of Science and Technology
Current Pharmaceutical Design | Year: 2015

Regenerative medicine holds much promise in assisting patients to recover from injured or lost tissues and organs through organism reconstruction. Three-dimensional (3D) biomimetic models via various approaches can be used by pharmaceutical industry for controlled drug delivery. With proper biomaterials and engineering technologies, drugs can be released in a rate-manipulated manner towards targeted regions with spatial and temporal effects. Much of the success is a result of a combination of growth factors, stem cells, biomaterials, nanotechnologies, electrospinning and 3D printing techniques mimicking in vivo angiogenesis, histogenesis and tumorigenesis processes. This interdisciplinary field on biomimetic drug delivery and regenerative medicine has already opened up a new avenue for medical progress and reformation. This article presents a comprehensive review of the 3D biomimetic models in the pertinent fields of tissue and organ manufacturing, cell-material mutual interactions, bioactive agent carrier systems and anti-cancer drug delivery methods. Particularly, the potential trends and challenges of tissue and organ manufacturing are discussed from different perspectives. © 2015 Bentham Science Publishers.


Sun Z.,Huazhong University of Science and Technology | Sun Z.,ESPCI ParisTech | Sun Z.,CNRS Physics and Materials Study Laboratory | Chang H.,Huazhong University of Science and Technology | Chang H.,Tohoku University
ACS Nano | Year: 2014

Graphene and graphene-like two-dimensional (2D) materials have attracted much attention due to its extraordinary electronic and optical properties, which accommodate a large potential in optoelectronic applications such as photodetection. However, although much progress has been made, many challenges exist in fundamental and practical aspects hindering graphene and graphene-like 2D materials from photodetector and other photonic and optoelectronic applications. Here, we review the recent progress in photodetection based on graphene and graphene-like 2D materials and start with the summary of some most important physical mechanisms, including photoelectric, photo-Thermoelectric, and photo-bolometric regimes. Then methodology-level discussions are given from viewpoints of state-of-The-Art designs in device geometry and materials. It is worth emphasizing that emerging photodetection and photodetectors based on graphene-like 2D materials such as metal chalcogenide nanosheets are reviewed systematically. Finally, we conclude this review in a brief discussion with remaining challenges in photodetection of two-dimensional photonics and optoelectronics (2D POE) and note that complete understandings of 2D materials and 2D POE may inspire solar energy conversion and other new applications. © 2014 American Chemical Society.


Wu J.,Huazhong University of Science and Technology | Guo Z.Y.,Tsinghua University
Industrial and Engineering Chemistry Research | Year: 2014

Aside from the introductory and concluding remarks, this article is divided into four sections. Following a brief description of the concepts of entransy and entransy dissipation, which measures the irreversibility of heat transfer not related to heat-to-work conversion, a temperature-heat-flow-rate diagram (T-Q diagram) is applied to evaluate the heat-transfer irreversibility graphically, which can be used to reflect the performance of self-heat recuperation technology (SHRT) in chemical engineering. The entransy analyses in terms of temperature-heat-flow-rate diagrams for the chemical processes with gas and vapor/liquid streams show that a lower entransy-dissipation rate corresponds to better heat-recovery performance. Finally, both the quantitative entransy and exergy analyses indicate that, compared to the conventional self-heat exchange process, a process with SHRT achieved by changing the pressure of the effluent stream with a compressor provides much higher heat recovery and much lower energy requirement because of the much lower heat-transfer irreversibility measured by the entransy-dissipation rate or exergy-destruction rate. In addition, the differences between the entransy and exergy analyses are also discussed. © 2013 American Chemical Society.


Wang D.,Huazhong University of Science and Technology | Yu Y.,Cornell University | He H.,Huazhong University of Science and Technology | Wang J.,Huazhong University of Science and Technology | And 2 more authors.
ACS Nano | Year: 2015

We have developed a template-free procedure to synthesize Co3O4hollow-structured nanoparticles on a Vulcan XC-72 carbon support. The material was synthesized via an impregnation-reduction method followed by air oxidation. In contrast to spherical particles, the hollow-structured Co3O4nanoparticles exhibited excellent lithium storage capacity, rate capability, and cycling stability when used as the anode material in lithium-ion batteries. Electrochemical testing showed that the hollow-structured Co3O4particles delivered a stable reversible capacity of about 880 mAh/g (near the theoretical capacity of 890 mAh/g) at a current density of 50 mA/g after 50 cycles. The superior electrochemical performance is attributed to its unique hollow structure, which combines nano- and microscale properties that facilitate electron transfer and enhance structural robustness. © 2015 American Chemical Society.


Zhang X.,Huazhong University of Science and Technology | Zhang X.,Hubei Key Laboratory of Engineering Structural Analysis and Safety Assessment | Zhang H.,Wuhan Textile University
Thin-Walled Structures | Year: 2012

Energy absorption characteristics of regular polygonal columns and rhombic columns under quasi-static axial compression are investigated by using an INSTRON materials testing machine. The influence of central angle on deformation mode and mean crushing force of angle elements is studied. Numerical investigations are also carried out to study the crush resistance of polygonal columns and angle elements under quasi-static and dynamic axial compression. The numerical predicted crushing force and deformation mode of the polygonal columns are found to be in good agreement with the experimental results. In addition, based on the experiment observations, some discussion about the deformation mechanism of energy absorption is presented. © 2012 Elsevier Ltd. All rights reserved.


Su H.,Huazhong University of Science and Technology | Chen M.Z.Q.,University of Hong Kong | Lam J.,University of Hong Kong | Lin Z.,University of Virginia
IEEE Transactions on Circuits and Systems I: Regular Papers | Year: 2013

This paper investigates the problem of leader-following consensus of a linear multi-agent system on a switching network. The input of each agent is subject to saturation. Low gain feedback based distributed consensus protocols are developed. It is established that, under the assumptions that each agent is asymptotically null controllable with bounded controls and that the network is connected or jointly connected, semi-global leader-following consensus of the multi-agent system can be achieved. Numerical examples are presented to illustrate this result. © 2004-2012 IEEE.


Xiao R.,Huazhong University of Science and Technology | Chen T.,Zhejiang GongShang University
International Journal of Bio-Inspired Computation | Year: 2013

Swarm intelligence (SI) and artificial immune system (AIS) are both derived from imitation of nature biology system. Their common characteristic is that they both have simple individuals but appear emergence characteristic in population level through interaction among individuals. In order to explore inherent similarity and difference of complex system, we take two typical forms of swarm intelligence (ant colony system and particle swarm optimisation), and AIS as objectives to study this characteristic in this paper. First, we discuss the similarity between two biology systems from system structure and operation mechanism. In addition, we also illustrate the difference between two systems from algorithm design, individual diversity and shape space. At the end of the paper, numerical experiment is used to test the performance of swarm intelligence techniques and AIS, where benchmark test functions include unimodal and multimodal function optimisation problems. Besides, combined with a concrete example, travelling salesman problem (TSP), the generality and feature of these two systems in solving complex problems are discussed in detail. The objective of the paper is to set up inherent connection and difference between two unlike systems, which not only has important theoretical significance but also has significant actual value to reveal production and operation mechanism of human intelligence. Copyright © 2013 Inderscience Enterprises Ltd.


Yang B.,Wuhan University of Technology | Fang H.,Huazhong University of Science and Technology
Automatica | Year: 2010

This communique presents forced second-order consensus protocols with communication time-delays for the network of agents with double integrator dynamics and gives a measure of the robustness of the protocols to the communication time-delays. By employing a frequency domain method, it is proven that the forced consensus is achieved asymptotically for appropriate time-delay if the network is connected. Particularly, the maximum fixed time-delay that can be tolerated by the network is found. The forced consensus protocols are distributed in the sense that each agent only needs information from its neighboring agents, which reduces the complexity of connections between agents significantly. Numerical simulation results are provided to demonstrate the effectiveness and the sharpness of the theoretical results. © 2010 Elsevier Ltd. All rights reserved.


Wang Z.,Huazhong University of Science and Technology | Cheng Q.,Huazhong University of Science and Technology | Zhou H.,Tsinghua University
International Journal of Thermal Sciences | Year: 2013

Within a graded index medium, the radiative energy rays propagate in curved paths and with a varied speed of propagation, making the solution of the transient radiative transfer complex and difficult. The DRESOR method is extended to calculate the time-resolved reflectance and transmittance from a one-dimensional, non-emitting, absorbing, anisotropically scattering medium with a linear increasing graded index exposed to a collimated truncated Gaussian pulse. Comparisons are made with the results obtained by DOM and DFEM, which indicate that the DRESOR method is accurate and effective. Compared with uniform graded index, the increase in the gradient of the refractive index significantly reduces the peak value of the reflectance and transmittance, delays the occurrence time of the transmittance and increases the duration time. The double-peak phenomenon of the time-resolved transmittance is caused by the fact that the maximum values of intensity in different directions appear at different times, which occur much later as the polar angle increases. The double-peak phenomenon of the time-resolved transmittance becomes more obvious as the increase in the graded index, the scattering albedo and the optical thickness; and the decrease in the anisotropically scattering phase function coefficient. © 2013 Elsevier Masson SAS. All rights reserved.


Dong H.,Institute for Infocomm Research | Tang M.,Huazhong University of Science and Technology | Gong Y.,Institute for Infocomm Research
Optics Express | Year: 2012

The optical axes of achromatic waveplate retarders (AWR) may deform from ideal linear eigenpolarizations and be frequency-dependent owing to the imperfect design and fabrication. Such deformations result in the ellipticity error and the orientation error of an AWR away from the nominal values. In this paper, we address the measurement errors of Stokes parameters induced by deformation of optical axes of AWRs in roatatable retarder fixed polarizer (RRFP) Stokes polarimeters. A set of theoretical formulas is derived to reveal that such measurement errors actually depend on both retardance and angular orientations of the AWR in use, as well as the state of polarization (SOP) under test. We demonstrate that, by rotating the AWR to N (N≥5) uniformly spaced angles with the angle step of 180°/N or 360°/N, the measurement errors of Stokes parameters induced by the ellipticity error of the AWR can be suppressed compared with the result using any set of four specific angles, especially when the SOP under test is nearly circular. On the other hand, the measurement errors induced by the orientation error of the AWR have more complicated relationships with the angular orientations of the AWR: 1) when the SOP under test is nearly circular, above-mentioned N (N≤5) uniformly spaced angles also lead to much smaller measurement errors than any set of four specific angles; 2) when the SOP under test is nearly linear, N (N≤5) uniformly spaced angles result in smaller or larger measurement errors, depending on the SOP under test, compared with the usually-recommended sets of four specific angles. By theoretical calculations and numerical simulations, we can conclude that the RRFP Stokes polarimeters employing angle sets of N (N≤5) uniformly spaced angles, (± 90°,.54°,.18°, 18°, 54°) for instance, can effectively reduce the measurement errors of Stokes parameters induced by the optical axes deformation of the AWR. © 2012 Optical Society of America.


Dai J.,University of Rochester | Zhang X.-C.,University of Rochester | Zhang X.-C.,Huazhong University of Science and Technology
Optics Letters | Year: 2014

We experimentally demonstrated terahertz (THz) wave emission from thin metal (gold) films excited by asymmetrical optical fields synthesized using an in-line phase compensator. By driving the electrons in thin metal films asymmetrically, THz wave emission is observed at normal incidence of two-color pump beams. Coherent control of THz wave emission from metal films suggests that a mechanism similar to that of the air-plasma THz source excited by two-color laser fields can be used to describe the generation processes. © 2014 Optical Society of America.


Ouyang M.,Huazhong University of Science and Technology | Duenas-Osorio L.,Rice University
Chaos | Year: 2012

This paper introduces an approach to assess and improve the time-dependent resilience of urban infrastructure systems, where resilience is defined as the systems' ability to resist various possible hazards, absorb the initial damage from hazards, and recover to normal operation one or multiple times during a time period T. For different values of T and its position relative to current time, there are three forms of resilience: previous resilience, current potential resilience, and future potential resilience. This paper mainly discusses the third form that takes into account the systems' future evolving processes. Taking the power transmission grid in Harris County, Texas, USA as an example, the time-dependent features of resilience and the effectiveness of some resilience-inspired strategies, including enhancement of situational awareness, management of consumer demand, and integration of distributed generators, are all simulated and discussed. Results show a nonlinear nature of resilience as a function of T, which may exhibit a transition from an increasing function to a decreasing function at either a threshold of post-blackout improvement rate, a threshold of load profile with consumer demand management, or a threshold number of integrated distributed generators. These results are further confirmed by studying a typical benchmark system such as the IEEE RTS-96. Such common trends indicate that some resilience strategies may enhance infrastructure system resilience in the short term, but if not managed well, they may compromise practical utility system resilience in the long run. © 2012 American Institute of Physics.


Patent
Huazhong University of Science, Technology and Cornell University | Date: 2014-03-21

A method for preparing a material composition comprising a hollow transition metal oxide nanoparticle supported upon a carbon material support includes a solution impregnation process step, followed by a thermal reduction process step and finally a thermal oxidation process step. The material composition, an electrode and an electrical component such as but not limited to a battery are all predicated at least in-part upon the material composition prepared in accord with the foregoing method. The foregoing material composition, electrode, battery and method may ultimately provide a LIB with enhanced performance.


Patent
Commercial Aircraft Corporation Of China Ltd, Shanghai Aircraft Design, Research Institute, Huazhong University of Science and Technology | Date: 2013-05-22

An icing detector probe includes three sections arranged sequentially along the direction of air flow, namely, a first section (I), a second section (II) and a third section (III). Wherein, the shape of the outer surface of the first section (I) is suitable for collecting droplets in the air flow; the shape of the outer surface of the second section (II) is suitable for full decelerating and releasing latent heat of large droplets during their movements; the outer surface of the third section (III) is suitable for icing of large droplets. The probe could distinguish and identify large droplets icing, thus effectively detecting it. Furthermore, it could effectively detect types of traditional icing, thus being helpful for exact detection of icing thickness. An icing detector including said icing detector probe is also provided.


Patent
Huazhong University of Science, Technology and Commercial Aircraft Corporation Of China | Date: 2011-06-30

An icing detector probe includes three sections arranged sequentially along the direction of air flow, namely, a first section, a second section and a third section. The shape of the outer surface of the first section is suitable for collecting droplets in the air flow. The shape of the outer surface of the second section is suitable for full decelerating and releasing latent heat of large droplets during their movements. The outer surface of the third section is suitable for icing of large droplets. The probe detects icing by distinguishing and identify large droplets icing. The probe effectively detects types of traditional icing, thus being helpful for exact detection of icing thickness. An icing detector including said icing detector probe is also provided.


Zhang J.,Huazhong University of Science and Technology | Zhang J.,University of Rochester
Optics Letters | Year: 2014

We present an investigation of the polarization dependence of THz air-biased coherent detection (ABCD) on the polarization directions of fundamental waves. The intensity, ellipticity, and polarization angle of the THz-fieldinduced second-harmonic are affected by the air plasma birefringence and can be predicted by cross-phase modulation theory. Due to the plasma birefringence, the polarization state of THz waves cannot be determined by the polarization state of the second harmonic with the traditional polarization measurement method. It would be inaccurate to measure arbitrary THz-wave polarization in a single scan with THz ABCD when the birefringence effect is significant. © 2014 Optical Society of America.


Chen M.,Huazhong University of Science and Technology | Mao S.,Auburn University | Liu Y.,Tsinghua University
Mobile Networks and Applications | Year: 2014

In this paper, we review the background and state-of-the-art of big data. We first introduce the general background of big data and review related technologies, such as could computing, Internet of Things, data centers, and Hadoop. We then focus on the four phases of the value chain of big data, i.e., data generation, data acquisition, data storage, and data analysis. For each phase, we introduce the general background, discuss the technical challenges, and review the latest advances. We finally examine the several representative applications of big data, including enterprise management, Internet of Things, online social networks, medial applications, collective intelligence, and smart grid. These discussions aim to provide a comprehensive overview and big-picture to readers of this exciting area. This survey is concluded with a discussion of open problems and future directions. © 2014 Springer Science+Business Media New York.


Grant
Agency: Cordis | Branch: FP7 | Program: CP-FP | Phase: AAT.2010.4.1-8. | Award Amount: 3.68M | Year: 2010

This proposal is in response to the call for EU and China collaboration on casting large Ti structures. The consortium consists of 7 EU and 7 Chinese partners. This proposal aims to make a step-change for casting of large Ti components by overcoming some key challenges in the casting process. Such a step-change is critical if the production of large Ti components is to meet the requirement in cost reduction by endusers, the requirement of CO2 reduction and raw material wastage reduction in every step of component manufacturing process by the endusers and by the society. This step change will involve the development of the centrifugal casting process by which the filling of thin sections of large Ti structures will be improved so that significantly fewer and smaller defects will be present in the component and a significantly higher production yield rate will be achieved. Further development will be carried to improve the gravity casting process which is important for casting asymmetrical components such as Ti airframes. Those developments will be closely coupled with the development of computer modelling in terms of better understanding and predicting liquid filling of the mould, defect formation and distribution, control of the dimensional accuracy of the cast component together with the development of a stronger wax and optimum ceramic mould material if required in order to meet the component dimension tolerance specified. The microstructure and mechanical properties including that of heat treated and welded castings must be optimised. If successful, this project will lead to significant cost reduction in producing large Ti components; removal the USA monopoly of supply of aeroengine Ti casings and significant reduction of CO2 and of Ti raw material wastage incurred in current manufacturing processes. It will also lead to more application of light Ti structures in aerospace and space, thus weight and fuel reduction by making Ti structure commercially viable.


Patent
Commercial Aircraft Corporation Of China Ltd, Shanghai Aircraft Design, Research Institute, Huazhong University of Science and Technology | Date: 2013-05-08

A detecting device for detecting icing by an image includes an image acquiring system (1-A) and an image processing system (2-A).The image acquiring system (1-A) can acquire an image of an objects surface. The image processing system (2-A) can analyze the image and obtain an icing condition of the objects surface. The detecting device is simple and reliable. It can identify the category of the icing effectively. So, it can improve the accurateness of the icing detection significantly and can accomplish the detection of the objects whole surface. Furthermore, it can detect an icing condition of a super-cooled large droplet. A method for detecting an icing condition of an objects surface using the detecting device is also provided.


Patent
Huazhong University of Science, Technology and Commercial Aircraft Corporation Of China | Date: 2011-06-16

A detecting device for detecting icing by an image includes an image acquiring system (1-A) and an image processing system (2-A). The image acquiring system (1-A) can acquire an image of an objects surface. The image processing system (2-A) can analyze the image and obtain an icing condition of the objects surface. The detecting device is simple and reliable. It can identify the category of the icing effectively. So, it can improve the accurateness of the icing detection significantly and can accomplish the detection of the objects whole surface. Furthermore, it can detect an icing condition of a super-cooled large droplet. A method for detecting an icing condition of an objects surface using the detecting device is also provided.


News Article | September 6, 2016
Site: www.rdmag.com

Electronics integrated into textiles are gaining in popularity: Systems like smartphone displays in a sleeve or sensors to detect physical performance in athletic wear have already been produced. The main problem with these systems tends to be the lack of a comfortable, equally wearable source of power. Chinese scientists are now aiming to obtain the necessary energy from body heat. In the journal Angewandte Chemie, they have introduced a flexible, wearable thermocell based on two different gel electrolytes. Our muscle activity and metabolism cause our bodies to produce constant heat, some of which is released through the skin into the environment. Because of the relatively small temperature difference between skin (approximately 32 °C) and the temperature of our surroundings, it is not so easy to make use of body heat. Previous thermoelectric generators, such as those based on semiconductors, produce too little energy, are costly, or are too brittle for use in wearable systems. Thermocells with electrolyte solutions are difficult to integrate into extensive wearable systems. A team led by Jun Zhou at Huazhong University of Science and Technology (Wuhan, China) has now found a solution to this problem: thermocells with gel-based electrolytes. The researchers are making use of the thermogalvanic effect: if two electrodes in contact with an electrolyte solution--or an electrolyte gel--are kept at different temperatures, a potential difference is generated. The ions of a redox pair in the electrolyte can rapidly switch between two different charge states, accepting or releasing electrons at electrodes with different temperature. In order to use this to produce a current, the scientists combined two types of cells containing two different redox pairs. Each cell consists of two tiny metal plates that act as electrodes, with an electrolyte gel in between. The first cell type contains the Fe2+/Fe3+ redox pair. The second type of cell contains the complex ions [Fe(CN)6]3-/[Fe(CN)6]4-. Because of the choice of these redox pairs, in cell type 1, the cold end gives a negative potential, while in type 2, the cold end gives a positive potential. The researchers arranged many of these two types of cells into a checkerboard pattern. The cells were connected to each other by metal plates alternating above and below, to link them into a series. They then integrated this "checkerboard" into a glove. When the glove is worn, the desired temperature difference results between the upper and lower plates. This produces a voltage between neighboring cells, and the voltage adds up. This makes it possible to generate current to power a device or charge a battery. In an environment at 5 °C, it was possible to produce 0.7 volts and about 0.3 μW. By optimizing this system, it should be possible to improve the power, even with smaller temperature gradients.


BEIJING, Dec. 16, 2016 (GLOBE NEWSWIRE) -- Autohome Inc. (“Autohome” or the “Company”) (NYSE:ATHM), a leading online destination for automobile consumers in China, today announced that each of the proposed resolutions submitted for shareholder approval has been approved at its annual general meeting of shareholders held in Hong Kong today (the “2016 AGM”). Specifically, Autohome’s shareholders adopted the following resolutions: 1. Mr. Junling Liu be re-elected as a director of the Company and each director of the Company be and is hereby authorized to take any and every action that might be necessary to effect the foregoing resolution as such director, in his or her absolute discretion, thinks fit. 2. Mr. Tianruo Pu be appointed as a director of the Company and each director of the Company be and is hereby authorized to take any and every action that might be necessary to effect the foregoing resolution as such director, in his or her absolute discretion, thinks fit. 3. Mr. Dazong Wang be appointed as a director of the Company and each director of the Company be and is hereby authorized to take any and every action that might be necessary to effect the foregoing resolution as such director, in his or her absolute discretion, thinks fit. 4. Approve, confirm and ratify the adoption of the 2016 Share Incentive Plan II (as amended by Amendment No. 1 to the 2016 Share Incentive Plan II). Pursuant to Article 88 of the Articles of Association of the Company, each of Mr. Guangfu Cui, Mr. Ted Tak-Tai Lee and Mr. Junling Liu is subject to retirement as director of the Company by rotation as of the 2016 AGM on December 16, 2016. Mr. Junling Liu was re-elected as a director of the Company at the 2016 AGM pursuant to the above resolution adopted by the shareholders of the Company. Mr. Tianruo Pu and Mr. Dazong Wang were appointed as directors of the Company at the 2016 AGM pursuant to the above resolutions adopted by the shareholders of the Company. The Board has reviewed the independence of Mr. Pu and Mr. Wang, and determined that they satisfy the "independence" requirements of Section 303A of the Corporate Governance Rules of the New York Stock Exchange and the "independence" standards under Rule 10A-3 under the Securities Exchange Act of 1934. Mr. Tianruo Pu currently serves as an independent director and chairman of the audit committee of Wowo Limited, a Chinese internet e-commerce company listed on the NASDAQ, as an independent director and member of the audit committee of Renren Inc., a Chinese social network platform listed on the New York Stock Exchange, and as an independent director and chairman of the audit committee of 3SBio Inc., a Chinese bio-pharmaceutical company listed on the Hong Kong Stock Exchange. Mr. Pu is also the chief financial officer of Zhaopin Limited, an internet recruiting company listed on the New York Stock Exchange. Mr. Pu has more than twenty years of work experience in finance and accounting in both the United States and China. Prior to joining Zhaopin, Mr. Pu was the chief financial officer of UTStarcom, a global telecommunications equipment company listed on the NASDAQ, and prior to that, Mr. Pu served as the chief financial officer at China Nuokang Bio-Pharmaceutical Inc. Mr. Pu received an MBA degree from Northwestern University Kellogg School of Management in 2000 and a master of science degree in accounting from the University of Illinois in 1996. Mr. Dazong Wang has been the founder and the chairman of Ophoenix Capital Management since 2011. From 2008 to 2011, Mr. Wang was the president and chief executive officer of Beijing Automotive Industry Corporation. Between 2006 to 2008, Mr. Wang served as the vice president of Shanghai Automotive Industry Corporation, where he was responsible for engineering and key component operations. Prior to this, Mr. Wang served several positions in General Motors Company, or GM, from 1985 to 2006, including, senior technician, China country manager and engineering director for North America operations. Mr. Wang received a Ph.D degree from Cornell University and a master of science degree from Huazhong University of Science and Technology in China. Autohome Inc. (NYSE:ATHM) is the leading online destination for automobile consumers in China.  Its mission is to enhance the car-buying and ownership experience for auto consumers in China. Autohome provides professionally produced and user-generated content, a comprehensive automobile library, and extensive automobile listing information to automobile consumers, covering the entire car purchase and ownership cycle.  The ability to reach a large and engaged user base of automobile consumers has made Autohome a preferred platform for automakers and dealers to conduct their advertising campaigns. Further, the Company’s dealer subscription and advertising services allow dealers to market their inventory and services through Autohome’s platform, extending the reach of their physical showrooms to potentially millions of internet users in China and generating sales leads for them. The Company offers sales leads, data analysis, and marketing services to assist automakers and dealers with improving their efficiency and facilitating transactions.  As a transaction-centric company, Autohome operates its “Autohome Mall,” a full-service online transaction platform, to facilitate transactions for automakers and dealers.  Further, through its website and mobile applications, it also provides other value-added services, including auto financing, auto insurance, used car transactions, and aftermarket services. For further information, please visit www.autohome.com.cn.


News Article | April 28, 2016
Site: www.materialstoday.com

The secret to making the best energy storage materials is growing them with as much surface area as possible. This requires just the right mixture of ingredients prepared in a specific amount and order at just the right temperature to produce a thin sheet of material with the perfect chemical consistency to store energy. A team of researchers from Drexel University, and Huazhong University of Science and Technology (HUST) and Tsinghua University in China, recently discovered a way to improve the recipe and make the resulting materials both bigger and better at soaking up energy. The secret? Just add salt. The team's findings, which are published in a paper in Nature Communications, show that using salt crystals as a template to grow thin sheets of conductive metal oxides produces materials that are larger and possess a greater chemical purity, making them better suited for gathering ions and storing energy. "The challenge of producing a metal oxide that reaches theoretical performance values is that the methods for making it inherently limit its size and often foul its chemical purity, which makes it fall short of predicted energy storage performance," said Jun Zhou, a professor at HUST's Wuhan National Laboratory for Optoelectronics and an author of the paper. "Our research reveals a way to grow stable oxide sheets with less fouling that are on the order of several hundreds of times larger than the ones that are currently being fabricated." In an energy storage device – a battery or a capacitor, for example – energy is contained in the chemical transfer of ions from an electrolyte solution to thin layers of conductive materials. As these devices evolve, they're becoming smaller and capable of holding an electric charge for longer periods of time without needing a recharge. The reason for their improvement is that researchers are fabricating materials that are better equipped, structurally and chemically, for collecting and disbursing ions. In theory, the best materials for the job should be thin sheets of metal oxides, because their chemical structure and high surface area makes it easy for ions to bind to them – which is how energy storage occurs. But the metal oxide sheets that have been fabricated in labs thus far have fallen well short of their theoretical capabilities. According to the researchers, the problem lies in the process of making the metal oxide nanosheets, which involves either deposition from a gas or chemical etching. Both these processes often leave trace chemical residues that contaminate the material and prevent ions from bonding to it. In addition, materials made in this way are often just a few square micrometers in size. Using salt crystals as a substrate for growing the metal oxide crystals lets them spread out and form a larger sheet of oxide material. Analogous to making a waffle by dripping batter into a pan versus pouring it into a big waffle iron, the key to getting a big, sturdy product is getting the solution – be it batter or a chemical compound – to spread evenly over the template and stabilize in a uniform way. "This method of synthesis, called 'templating' – where we use a sacrificial material as a substrate for growing a crystal – is used to create a certain shape or structure," explained Yury Gogotsi, a professor in Drexel's College of Engineering and head of the A.J. Drexel Nanomaterials Institute, who was another author of the paper. "The trick in this work is that the crystal structure of salt must match the crystal structure of the oxide, otherwise it will form an amorphous film of oxide rather than a thin, strong and stable nanocrystal. This is the key finding of our research – it means that different salts must be used to produce different oxides." Researchers have used a variety of chemicals, compounds, polymers and objects as growth templates for nanomaterials, but this discovery shows the importance of matching a template to the structure of the material being grown. Salt crystals turn out to be the perfect substrate for growing oxide sheets of magnesium, molybdenum and tungsten. The precursor solution coats the sides of the salt crystals as the oxides begin to form. After they've solidified, the salt is dissolved in a wash, leaving nanometer-thin two-dimensional (2D) sheets on the sides of the salt crystals – and little trace of any contaminants that might hinder their energy storage performance. By making oxide nanosheets in this way, the only factors that limit their growth are the size of the salt crystals and the amount of precursor solution used. "Lateral growth of the 2D oxides was guided by salt crystal geometry and promoted by lattice matching and the thickness was restrained by the raw material supply. The dimensions of the salt crystals are tens of micrometers and guide the growth of the 2D oxide to a similar size," the researchers write in the paper. "On the basis of the naturally non-layered crystal structures of these oxides, the suitability of salt-assisted templating as a general method for synthesis of 2D oxides has been convincingly demonstrated." As predicted, the larger size of the oxide sheets equated to a greater ability to collect and disburse ions from an electrolyte solution – the ultimate test for energy storage devices. Results reported in the paper suggest that use of these materials may help in creating an aluminum-ion battery that could store more charge than the best lithium-ion batteries found in laptops and mobile devices today. Gogotsi, along with his students in Drexel’s Department of Materials Science and Engineering, has been collaborating with HUST since 2012 to explore a wide variety of materials for energy storage applications. The lead author of the Nature Communications paper, Xu Xiao, and co-author Tiangi Li, both Zhou's doctoral students, came to Drexel as exchange students to learn about its supercapacitor research. Those visits started a collaboration that was supported by Gogotsi's annual trips to HUST. While the partnership has already yielded five joint publications, Gogotsi speculates that this work is just beginning. "The most significant result of this work thus far is that we've demonstrated the ability to generate high-quality 2D oxides with various compositions," Gogotsi said. "I can certainly see expanding this approach to other oxides that may offer attractive properties for electrical energy storage, water desalination membranes, photocatalysis and other applications." This story is adapted from material from Drexel University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.


Home > Press > Adding some salt to the recipe for energy storage materials: Researchers use common table salt as growth template Abstract: The secret to making the best energy storage materials is growing them with as much surface area as possible. Like baking, it requires just the right mixture of ingredients prepared in a specific amount and order at just the right temperature to produce a thin sheet of material with the perfect chemical consistency to be useful for storing energy. A team of researchers from Drexel University, Huazhong University of Science and Technology (HUST) and Tsinghua University recently discovered a way to improve the recipe and make the resulting materials bigger and better and soaking up energy -- the secret? Just add salt. The team's findings, which were recently published in the journal Nature Communications, show that using salt crystals as a template to grow thin sheets of conductive metal oxides make the materials turn out larger and more chemically pure -- which makes them better suited for gathering ions and storing energy. "The challenge of producing a metal oxide that reaches theoretical performance values is that the methods for making it inherently limit its size and often foul its chemical purity, which makes it fall short of predicted energy storage performance," said Jun Zhou, a professor at HUST's Wuhan National Laboratory for Optoelectronics and an author of the research. Our research reveals a way to grow stable oxide sheets with less fouling that are on the order of several hundreds of times larger than the ones that are currently being fabricated." In an energy storage device -- a battery or a capacitor, for example -- energy is contained in the chemical transfer of ions from an electrolyte solution to thin layers of conductive materials. As these devices evolve they're becoming smaller and capable of holding an electric charge for longer periods of time without needing a recharge. The reason for their improvement is that researchers are fabricating materials that are better equipped, structurally and chemically, for collecting and disbursing ions. In theory, the best materials for the job should be thin sheets of metal oxides, because their chemical structure and high surface area makes it easy for ions to attach -- which is how energy storage occurs. But the metal oxide sheets that have been fabricated in labs thus far have fallen well short of their theoretical capabilities. According to Zhou, Tang and the team from HUST, the problem lies in the process of making the nanosheets -- which involves either a deposition from gas or a chemical etching -- often leaves trace chemical residues that contaminate the material and prevent ions from bonding to it. In addition, the materials made in this way are often just a few square micrometers in size. Using salt crystals as a substrate for growing the crystals lets them spread out and form a larger sheet of oxide material. Think of it like making a waffle by dripping batter into a pan versus pouring it into a big waffle iron; the key to getting a big, sturdy product is getting the solution -- be it batter, or chemical compound -- to spread evenly over the template and stabilize in a uniform way. "This method of synthesis, called 'templating' -- where we use a sacrificial material as a substrate for growing a crystal -- is used to create a certain shape or structure," said Yury Gogotsi, PhD, University and Trustee Chair professor in Drexel's College of Engineering and head of the A.J. Drexel Nanomaterials Institute, who was an author of the paper. "The trick in this work is that the crystal structure of salt must match the crystal structure of the oxide, otherwise it will form an amorphous film of oxide rather than a thing, strong and stable nanocrystal. This is the key finding of our research -- it means that different salts must be used to produce different oxides." Researchers have used a variety of chemicals, compounds, polymers and objects as growth templates for nanomaterials. But this discovery shows the importance of matching a template to the structure of the material being grown. Salt crystals turn out to be the perfect substrate for growing oxide sheets of magnesium, molybdenum and tungsten. The precursor solution coats the sides of the salt crystals as the oxides begin to form. After they've solidified, the salt is dissolved in a wash, leaving nanometer-thin two-dimensional sheets that formed on the sides of the salt crystal -- and little trace of any contaminants that might hinder their energy storage performance. By making oxide nanosheets in this way, the only factors that limit their growth is the size of the salt crystal and the amount of precursor solution used. "Lateral growth of the 2D oxides was guided by salt crystal geometry and promoted by lattice matching and the thickness was restrained by the raw material supply. The dimensions of the salt crystals are tens of micrometers and guide the growth of the 2D oxide to a similar size," the researchers write in the paper. "On the basis of the naturally non-layered crystal structures of these oxides, the suitability of salt-assisted templating as a general method for synthesis of 2D oxides has been convincingly demonstrated." As predicted, the larger size of the oxide sheets also equated to a greater ability to collect and disburse ions from an electrolyte solution -- the ultimate test for its potential to be used in energy storage devices. Results reported in the paper suggest that use of these materials may help in creating an aluminum-ion battery that could store more charge than the best lithium-ion batteries found in laptops and mobile devices today. Gogotsi, along with his students in the Department of Materials Science and Engineering, has been collaborating with Huazhong University of Science and Technology since 2012 to explore a wide variety of materials for energy storage application. The lead author of the Nature Communications article, Xu Xiao, and co-author Tiangi Li, both Zhou's doctoral students, came to Drexel as exchange students to learn about the University's supercapacitor research. Those visits started a collaboration, which was supported by Gogotsi's annual trips to HUST. While the partnership has already yielded five joint publications, Gogotsi speculates that this work is only beginning. "The most significant result of this work thus far is that we've demonstrated the ability to generate high-quality 2D oxides with various compositions," Gogotsi said. "I can certainly see expanding this approach to other oxides that may offer attractive properties for electrical energy storage, water desalination membranes, photocatalysis and other applications." For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


News Article | November 17, 2016
Site: www.eurekalert.org

ANN ARBOR--An international team of scientists led by the University of Michigan has discovered a new type of photoreceptor--only the third to be found in animals--that is about 50 times more efficient at capturing light than the rhodopsin in the human eye. The new receptor protein, LITE-1, was found among a family of taste receptors in invertebrates, and has unusual characteristics that suggest potential future applications ranging from sunscreen to scientific research tools, the team noted in findings scheduled to be published Nov. 17 in the journal Cell. "Our experiments also raise the intriguing possibility that it might be possible to genetically engineer other new types of photoreceptors," said senior study author Shawn Xu, a faculty member of the U-M Life Sciences Institute, where his lab is located. The LITE-1 receptor was discovered in the eyeless, millimeter-long roundworms known as nematodes, a common model organism in bioscience research. "LITE-1 actually comes from a family of taste receptor proteins first discovered in insects," said Xu, who is also a professor in the Department of Molecular and Integrative Physiology at the U-M Medical School. "These, however, are not the same taste receptors as in mammals." Xu's lab previously demonstrated that although they lack eyes, the worms will move away from flashes of light. The new research goes a step further, showing that LITE-1 directly absorbs light, rather than being an intermediary that senses chemicals produced by reactions involving light. "Photoreceptors convert light into a signal that the body can use," Xu said. "LITE-1 is unusual in that it is extremely efficient at absorbing both UV-A and UV-B light--10 to 100 times greater than the two other types found in the animal kingdom: opsins and cryptochromes. The next step is to better understand why it has these amazing properties." The genetic code of these receptor proteins is also very different from other types of photoreceptors found in plants, animals and microbes, Xu said. Characterizing the current research as an "entry point," the researchers said the discovery might prove useful in a variety of ways. With further study, for example, it might be possible to develop LITE-1 into a sunscreen additive that absorbs harmful rays, or to further scientific research by fostering light sensitivity in new types of cells, the scientists wrote in the paper. Animal photoreceptors typically have two components: a base protein and a light-absorbing chromophore (a role played by retinal, or vitamin A, in human sight). When you break these photoreceptors apart, the chromophore still retains some of its functionality. This is not the case for LITE-1. Breaking it apart, or "denaturing" it, completely stops its ability to absorb light, rather than just diminishing it--showing that it really is a different model, Xu said. The researchers also determined that within the protein, having the amino acid tryptophan in two places was critical to its function. When a nonlight-sensitive protein in the same family, GUR-3, was modified to add the corresponding tryptophan residues, it reacted strongly to ultraviolet light--with about a third the sensitivity to UV-B as LITE-1. "This suggests scientists may be able to use similar techniques to genetically engineer other new photoreceptors," Xu said. The research was supported by the National Eye Institute, National Natural Science Foundation of China, Ministry of Education of China, Program for Changjiang Scholars and Innovative Research Team in University, and the National Institute of General Medical Sciences. Additional authors include Jianke Gong and Bi Zhang of U-M and Huazhong University of Science and Technology; Jianfeng Liu of Huazhong University of Science and Technology; Yiyuan Yuan of U-M and Case Western Reserve University; Alex Ward, Lijun Kang and Jianfeng Liu of U-M; Zhiping Wu and Junmin Peng of St. Jude Children's Research Hospital; and Zhaoyang Feng of Case Western Reserve University.


Gu L.,Harbin Institute of Technology | Wang J.,Huazhong University of Science and Technology | Wang J.,Harbin Institute of Technology | Zou Z.,Harbin Institute of Technology | Han X.,Harbin Institute of Technology
Journal of Hazardous Materials | Year: 2014

Anatase TiO2 nanosheets with dominant {001} facets were hybridized with graphitic carbon nitride (g-C3N4) using a facile solvent evaporation method. On top of the superior photocatalytic performance of highly reactive {001} facets, the hybridization with g-C3N4 is confirmed to further improve the reactivity through degrading a series of organic molecules under both UV- and visible-light irradiation. It is proposed that an effective charge separation between g-C3N4 and TiO2 exists in the photocatalytic process, i.e., the transferring of photogenerated holes from the valence band (VB) of TiO2 to the highest occupied molecular orbital (HOMO) of g-C3N4, and the injecting of electrons from the lowest unoccupied molecular orbital (LUMO) of g-C3N4 to the conduction band (CB) of TiO2. Due to this synergistic effect, the enhancement of UV- and visible-light photoactivity over the hybrid is achieved. Furthermore, it has been revealed that holes were the main factor for the improved photoactivity under UV-light, while the OH radicals gained the predominance for degrading organic molecules under visible-light. Overall, this work would be significant for fabricating efficient UV-/visible-photocatalysts and providing deeper insight into the enhanced mechanisms of π-conjugated molecules hybridized semiconductors. © 2014 Elsevier B.V.


Song T.,Huazhong University of Science and Technology | Pan L.,Huazhong University of Science and Technology | Paun G.,Institute of Mathematics of the Romanian Academy
Theoretical Computer Science | Year: 2014

Spiking neural P systems (SN P systems, for short) are a class of membrane systems inspired from the way the neurons process information and communicate by means of spikes. In this paper, we introduce and investigate a new class of SN P systems, with spiking rules placed on synapses. The computational completeness is first proved, then two small universal SN P systems with rules on synapses for computing functions are constructed. Specifically, when using standard spiking rules, we obtain a universal system with 39 neurons, while when using extended spiking rules on synapses, a universal SN P system with 30 neurons is constructed. © 2014 Elsevier B.V.


Tan W.-W.,Central China Normal University | Cao X.-F.,Huazhong University of Science and Technology | Yu Y.-W.,Central China Normal University
Astrophysical Journal Letters | Year: 2013

The determination of the luminosity function (LF) of gamma-ray bursts (GRBs) is an important role for the cosmological applications of the GRBs, which, however, is seriously hindered by some selection effects due to redshift measurements. In order to avoid these selection effects, we suggest calculating pseudo-redshifts for Swift GRBs according to the empirical L-Ep relationship. Here, such a L-Ep relationship is determined by reconciling the distributions of pseudo- and real redshifts of redshift-known GRBs. The values of Ep taken from Butler's GRB catalog are estimated with Bayesian statistics rather than observed. Using the GRB sample with pseudo-redshifts of a relatively large number, we fit the redshift-resolved luminosity distributions of the GRBs with a broken-power-law LF. The fitting results suggest that the LF could evolve with redshift by a redshift-dependent break luminosity, e.g., Lb = 1.2 × 1051(1 + z) 2 erg s-1. The low- and high-luminosity indices are constrained to 0.8 and 2.0, respectively. It is found that the proportional coefficient between the GRB event rate and the star formation rate should correspondingly decrease with increasing redshifts. © 2013. The American Astronomical Society. All rights reserved.


Li H.,Huazhong University of Science and Technology | Wang X.,Japan International Center for Materials Nanoarchitectonics | Xu J.,Huazhong University of Science and Technology | Zhang Q.,Huazhong University of Science and Technology | And 4 more authors.
Advanced Materials | Year: 2013

As a promising candidate for optoelectronics, one-dimensional CdS nanostructures have drawn great scientific and technical interest due to their interesting fundamental properties and possibilities of utilization in novel promising optoelectronical devices with augmented performance and functionalities. This progress report highlights a selection of important topics pertinent to optoelectronical applications of one-dimensional CdS nanostructures over the last five years. This article begins with the description of rational design and controlled synthesis of CdS nanostructure arrays, alloyed nanostructucures and kinked nanowire superstructures, and then focuses on the optoelectronical properties, and applications including cathodoluminescence, lasers, light-emitting diodes, waveguides, field emitters, logic circuits, memory devices, photodetectors, gas sensors, photovoltaics and photoelectrochemistry. Finally, the general challenges and the potential future directions of this exciting area of research are highlighted. This Progress Report highlights a selection of important topics pertinent to optoelectronical applications of one-dimensional CdS nanostructures over the last five years. This article begins with a description of the rational design and controlled synthesis of CdS nanostructure arrays, alloyed nanostructucures and kinked nanowire superstructures, and then focuses on optoelectronical properties and applications. Finally, the general challenges and the potential future directions of this exciting area of research are highlighted. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Shang L.,NARI Group | Hu J.,Huazhong University of Science and Technology
IEEE Transactions on Energy Conversion | Year: 2012

This paper proposes an improved direct power control (DPC) strategy of grid-connected wind-turbine-driven doubly fed induction generators (DFIGs) when the grid voltage is unbalanced. The DPC scheme is based on the sliding mode control (SMC) approach, which directly regulates the instantaneous active and reactive powers in the stator stationary reference frame without the requirement of either synchronous coordinate transformation or phase angle tracking of grid voltage. The behavior of DFIGs by the conventional SMC-DPC, which takes no negative-sequence voltage into consideration, is analyzed under unbalanced grid voltage conditions. A novel power compensation method is proposed for the SMC-based DPC during network unbalance to achieve three selective control targets, i.e., obtaining sinusoidal and symmetrical stator current, removing stator interchanging reactive power ripples and canceling stator output active power oscillations, respectively. The active and reactive power compensation components are calculated via a simple method and the proposed three control targets can be achieved, respectively, without the need of extracting negative-sequence stator current components. Experimental results on a 2kW DFIG prototype are presented to verify the correctness and validity of the proposed control strategy and power compensation method. © 2012 IEEE.


Jiang J.,Central China Normal University | Li Y.,Huazhong University of Science and Technology | Liu J.,Central China Normal University | Huang X.,Central China Normal University | And 2 more authors.
Advanced Materials | Year: 2012

Metal oxide nanostructures are promising electrode materials for lithium-ion batteries and supercapacitors because of their high specific capacity/capacitance, typically 2-3 times higher than that of the carbon/graphite-based materials. However, their cycling stability and rate performance still can not meet the requirements of practical applications. It is therefore urgent to improve their overall device performance, which depends on not only the development of advanced electrode materials but also in a large part "how to design superior electrode architectures". In the article, we will review recent advances in strategies for advanced metal oxide-based hybrid nanostructure design, with the focus on the binder-free film/array electrodes. These binder-free electrodes, with the integration of unique merits of each component, can provide larger electrochemically active surface area, faster electron transport and superior ion diffusion, thus leading to substantially improved cycling and rate performance. Several recently emerged concepts of using ordered nanostructure arrays, synergetic core-shell structures, nanostructured current collectors, and flexible paper/textile electrodes will be highlighted, pointing out advantages and challenges where appropriate. Some future electrode design trends and directions are also discussed. The development of high-performance lithium-ion batteries/ supercapacitors relies on not only the use of advanced electrode materials but also the design of electrode architectures. This Review focuses on the recent advances in design of advanced metal oxide-based hybrid nanostructure electrode. Several recently emerged concepts of using ordered nanostructure arrays, synergetic core-shell structures, nanostructured current collectors, and flexible paper/textile electrodes are highlighted. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Yang H.,Huazhong University of Science and Technology | Liu J.,Chinese Research Academy of Environmental Sciences | Yang J.,Huazhong University of Science and Technology
Journal of Hazardous Materials | Year: 2011

Leaching copper from shredded particles of waste printed circuit boards (PCBs) was carried out in sulfuric acid solution using hydrogen peroxide as an oxidant at room temperature. The influence of system variables on copper recovery by leaching was investigated, such as sulfuric concentration, amount of hydrogen peroxide addition, waste PBCs particle size, presence of cupric ion, temperature and time. The results shown that the optimum addition amount was 100mL 15 (wt%) sulfuric acid solution and 10mL of 30% hydrogen peroxide for leaching 10g waste PCBs powder with a solid/liquid ratio of 1/10 for 3h at room temperature (∼23°C). Moreover leaching temperature and initial copper ion concentration had insignificant effect on the leaching recovery of copper. The effect of different particle size of shredded waste PCBs on leaching of copper was investigated under the optimum leaching condition. The results revealed that shredding pieces of waste PCBs smaller than 1mm was efficient and suitable for copper leaching. Then the leaching solution was concentrated to crystallize CuSO4·5H2O, and crystal liquor was reused for the next cycles. © 2011 Elsevier B.V.


Zhou C.,Central China Normal University | Zhang Y.,Central China Normal University | Li Y.,Huazhong University of Science and Technology | Liu J.,Central China Normal University
Nano Letters | Year: 2013

We have developed a supercapacitor electrode composed of well-aligned CoO nanowire array grown on 3D nickel foam with polypyrrole (PPy) uniformly immobilized onto or firmly anchored to each nanowire surface to boost the pseudocapacitive performance. The electrode architecture takes advantage of the high electrochemical activity from both the CoO and PPy, the high electronic conductivity of PPy, and the short ion diffusion pathway in ordered mesoporous nanowires. These merits together with the elegant synergy between CoO and PPy lead to a high specific capacitance of 2223 F g-1 approaching the theoretical value, good rate capability, and cycling stability (99.8% capacitance retention after 2000 cycles). An aqueous asymmetric supercapacitor device with a maximum voltage of 1.8 V fabricated by using our hybrid array as the positive electrode and activated carbon film as the negative electrode has demonstrated high energy density (∼43.5 Wh kg-1), high power density (∼5500 W kg-1 at 11.8 Wh kg-1) and outstanding cycleability (∼20 000 times). After charging for only ∼10 s, two such 4 cm2 asymmetric supercapacitors connected in series can efficiently power 5 mm diameter red, yellow, and green round LED indicators (lasting for 1 h for red LED) and drive a mini 130 rotation-motor robustly. © 2013 American Chemical Society.


Lai X.,Jiangxi University of Science and Technology | Lai X.,Huazhong University of Science and Technology | Lu Z.,Huazhong University of Science and Technology
Computers and Operations Research | Year: 2013

This paper presents a Multistart Iterated Tabu Search (MITS) algorithm for solving Bandwidth Coloring Problem (BCP) and Bandwidth MultiColoring Problem (BMCP). The proposed MITS algorithm exhibits several distinguishing features, such as integrating an Iterated Tabu Search (ITS) algorithm with a multistart method and a problem specific perturbation operator. Tested on two sets of 66 public benchmark instances widely used in the literature, the MITS algorithm achieves highly competitive results compared with the best performing algorithms, improving the previous best known results for 22 instances while matching the previous best known results for 39 ones. Furthermore, two important features of the proposed algorithm are analyzed.


Li H.,Huazhong University of Science and Technology | Li H.,University of Florida | Wu C.-Y.,University of Florida | Li Y.,University of Wisconsin - Milwaukee | Zhang J.,Huazhong University of Science and Technology
Applied Catalysis B: Environmental | Year: 2012

TiO 2 supported Mn-Ce mixed oxides (Mn-Ce/Ti) synthesized by an ultrasound-assisted impregnation method were employed to oxidize elemental mercury (Hg 0) at low temperatures in simulated low-rank (sub-bituminous and lignite) coal combustion flue gas and corresponding selective catalytic reduction (SCR) flue gas. The catalysts were characterized by BET surface area analysis, X-ray diffraction (XRD) measurement and X-ray photoelectron spectroscopy (XPS) analysis. The combination of MnO x and CeO 2 resulted in significant synergy for Hg 0 oxidation. The Mn-Ce/Ti catalyst was highly active for Hg 0 oxidation at low temperatures (150-250°C) under both simulated flue gas and SCR flue gas. The dominance of Mn 4+ and the presence of Ce 3+ on the Mn-Ce/Ti catalyst were responsible for its excellent catalytic performance. Hg 0 oxidation on the Mn-Ce/Ti catalyst likely followed the Langmuir-Hinshelwood mechanism, where reactive species on catalyst surface react with adjacently adsorbed Hg 0 to form Hg 2+. NH 3 consumed the surface oxygen and limited the adsorption of Hg 0, hence inhibiting Hg 0 oxidation over Mn-Ce/Ti catalyst. However, once NH 3 was cut off, the inhibited mercury oxidation activity could be completely recovered in the presence of O 2. This study revealed the possibility of simultaneously oxidizing Hg 0 and reducing NO x at low flue gas temperatures. Such knowledge is of fundamental importance in developing effective and economical mercury and NO x control technologies for coal-fired power plants. © 2011 Elsevier B.V.


Jiang J.,Central China Normal University | Li Y.,Huazhong University of Science and Technology | Liu J.,Central China Normal University | Huang X.,Central China Normal University
Nanoscale | Year: 2011

Lithium ion battery (LIB) is potentially one of the most attractive energy storage devices. To meet the demands of future high-power and high-energy density requirements in both thin-film microbatteries and conventional batteries, it is challenging to explore novel nanostructured anode materials instead of conventional graphite. Compared to traditional electrodes based on nanostructure powder paste, directly grown ordered nanostructure array electrodes not only simplify the electrode processing, but also offer remarkable advantages such as fast electron transport/collection and ion diffusion, sufficient electrochemical reaction of individual nanostructures, enhanced material-electrolyte contact area and facile accommodation of the strains caused by lithium intercalation and de-intercalation. This article provides a brief overview of the present status in the area of LIB anodes based on one-dimensional nanostructure arrays growing directly on conductive inert metal substrates, with particular attention to metal oxides synthesized by an anodized alumina membrane (AAM)-free solution-based or hydrothermal methods. Both the scientific developments and the techniques and challenges are critically analyzed. © 2010 The Royal Society of Chemistry.


Grant
Agency: Cordis | Branch: FP7 | Program: CP-FP-SICA | Phase: HEALTH-2009-4.3.2-3 | Award Amount: 3.90M | Year: 2010

Background A crucial goal of infectious disease surveillance is the early detection of epidemics, which is essential for disease control. In China, the current surveillance system is based on confirmed case reports and only covers notifiable diseases. In rural China, it is not practical for health units to perform laboratory tests to confirm disease and people are more likely to get old and emerging infectious diseases due to poor living conditions and closer contacts with wild animals and poultry. Syndromic surveillance which collects non-specific syndromes before diagnosis has great advantages in promoting the early detection of epidemics and reducing the necessities of disease confirmation. It will be especially effective for surveillance in resource poor settings. Objectives The objective is to improve the early detection of epidemics in rural China by integrating syndromic surveillance with case report surveillance system. This involves three main phases: (1) the development of an integrated surveillance system; (2) the implementation of this system; (3) the evaluation of this system. This project will contribute to knowledge, experience and evidence with regard to the development and implementation of an integrated surveillance system for the early warning of epidemics in similar settings. Methods This is an intervention study. The intervention tool will be an integrated surveillance system, combining syndromic surveillance with the existing case report surveillance in four selected counties in China. In order to evaluate the early warning capability of the new added syndromic surveillance, the timelines and validity of the alert signals triggered from syndromic surveillance will be compared against those from corresponding case report surveillance (as a reference) for the same region and time period. The acceptability, feasibility and economic evaluation of the whole integrated surveillance system will be conducted in a before and after study design.


Keil M.,Georgia State University | Rai A.,Georgia State University | Liu S.,Huazhong University of Science and Technology
European Journal of Information Systems | Year: 2013

Improving the management of information technology (IT) projects is of prime concern to both IS researchers and practitioners, as IT projects are notorious for poor process performance, frequently running over budget and behind schedule. Over the years, at least two separate streams of research have emerged with the aim of contributing to our understanding of IT project management. One of these focuses on the exercise of formal and informal controls, while another focuses on identifying and managing key risks such as those associated with requirements and users. Proponents of the control stream would argue that the exercise of formal and informal controls can improve process performance and there is some evidence that this is so. An obvious question that emerges, however, is how effective these controls are in the presence of particular risks. In this study, we seek to answer this question by developing and testing a research model that integrates these two streams of research. On the basis of data collected from 63 completed IT projects in China, we examine the moderating effects of requirements risk and user risk on the relationship between control (both formal and informal) and the process performance of IT projects. We contribute to the current state of knowledge by clearly demonstrating that both types of risk moderate the effects of formal and informal controls on performance. Specifically, both requirements risk and user risk were found to reduce the positive influence of controls on process performance, implying that implementing solid controls is a necessary, but not sufficient, condition to ensure good process performance. © 2013 Operational Research Society Ltd. All rights reserved.


Zhou S.,Nanchang Hangkong University | Zeng X.,Huazhong University of Science and Technology
Journal of Alloys and Compounds | Year: 2010

WC-reinforced Fe matrix composite coatings were prepared by laser induction hybrid rapid cladding (LIHRC). X-ray diffraction (XRD) was used to identify the phases and the growth characteristics of the precipitated carbides were observed by environmental scanning electron microscope (ESEM). The results show that WC particles are almost dissolved completely and interact with Fe-based alloy liquid in the molten pool to precipitate M6C carbides with different shapes during LIHRC. With increasing the weight percent of WC particles, the transition from the fine M6C carbides, which are precipitated in an intergranular network of the coarse α-Fe, to the coarse herringbone M6C eutectics and the primary faceted dendritic M 6C occur and the partially dissolved WC particles with an alloyed reaction layer can be occasionally found in the composite coating. Moreover, the eutectic M6C carbides in herringbone shape grow in terms of the intergrowth mode of layer and slice, while the primary faceted dendritic M 6C in equiaxial branched shape are only precipitated in the crossed region of the coarse eutectic carbides and grow in terms of dissolution and propagation. © 2010 Elsevier B.V.All rights reserved.


Liu Z.-W.,Huazhong University of Science and Technology | Guan Z.-H.,Huazhong University of Science and Technology | Shen X.,University of Waterloo | Feng G.,City University of Hong Kong
IEEE Transactions on Automatic Control | Year: 2012

In this technical note, an impulsive consensus algorithm is proposed for second-order continuous-time multi-agent networks with switching topology. The communication among agents occurs at sampling instants based on position only measurements. By using the property of stochastic matrices and algebraic graph theory, some sufficient conditions are obtained to ensure the consensus of the controlled multi-agent network if the communication graph has a spanning tree jointly. A numerical example is given to illustrate the effectiveness of the proposed algorithm. © 2012 IEEE.


Gu Y.,Huazhong University of Science and Technology | Jerome F.,University of Poitiers
Green Chemistry | Year: 2010

Glycerol, an organic waste generated by the biodiesel industry, has been recently proposed as a valuable green solvent. This review summarizes the advantages, disadvantages and potential uses of glycerol as a green solvent for catalysis, organic synthesis, separations and materials chemistry. In particular, through selected examples we show here that glycerol may combine the advantages of water (low toxicity, low price, large availability, renewability) and ionic liquids (high boiling point, low vapour pressure, low solubility in scCO 2). More generally, all these reported works contribute to increase the portfolio of available green solvents and afford innovative solutions to the substitution of the conventionally used volatile organic solvents. © The Royal Society of Chemistry 2010.


Zhou L.,Huazhong University of Science and Technology | Obrien P.,University of Manchester
Journal of Physical Chemistry Letters | Year: 2012

Mesocrystals are a new class of nanostructured solid materials, which are most often made of crystallographically oriented nanoparticles. Structural features, properties, and possible applications of mesocrystals are summarized in this paper. Due to their unique structural features and the resulting physical and physicochemical properties, mesocrystals are expected to play a significant role in improving the performance of materials in many applications. These are as diverse as heterogeneous photocatalysts, electrodes, optoelectronics, biomedical materials, hard templates, and lightweight structural materials. © 2012 American Chemical Society.


Zhang J.,Huazhong University of Science and Technology | Wang J.,Huaneng Lancang River Hydropower Co. | Yue C.,Huazhong University of Science and Technology
IEEE Transactions on Power Systems | Year: 2012

A small population-based particle swarm optimization (SPPSO) approach is presented to solve the problem of short-term hydrothermal scheduling (STHS). In the proposed approach, a novel mutation operation that selects the flying guides for each individual is employed to enhance the diversity of the small population. A DE algorithm is employed as an acceleration operation to accelerate the convergence of the approach in case that the optimal result has no significant improvements after several iterations. A migration operation is adopted to keep the swarm's crowding diversity above a desired level. In addition, a special repair procedure, instead of the penalty function approach, is applied to handle the complex equality constraints of STHS. The effectiveness of the approach is demonstrated through three hydrothermal test systems published in literature. The results are also compared with those obtained by other evolutionary methods. The fuel cost as well as other performance of the proposed approach has been found to be quite impressive. It is shown that the SPPSO approach can provide a better solution at lesser computational time and effort. © 2006 IEEE.


Wu Q.,Huazhong University of Science and Technology | Hao J.-K.,University of Angers
Expert Systems with Applications | Year: 2015

Combinatorial auctions (CAs) where bidders can bid on combinations of items is an important model in many application areas. CAs attract more and more attention in recent years due to its relevance to fast growing electronic business applications. In this paper, we study the winner determination problem (WDP) in CAs which is known to be NP-hard and thus computationally difficult in the general case. We develop a solution approach for the WDP by recasting the WDP into the maximum weight clique problem (MWCP) and solving the transformed problem with a recent heuristic dedicated to the MWCP. The computational experiments on a large range of 530 benchmark instances show that the clique-based approach for the WDP not only outperforms the current best performing WDP heuristics in the literature both in terms of solution quality and computation efficiency, but also competes very favorably with the powerful CPLEX solver. © 2014 Elsevier Ltd. All rights reserved.


Lu B.,Nanchang Hangkong University | Li N.,Huazhong University of Science and Technology
Applied Surface Science | Year: 2015

Various geometric microstructures on aluminum alloy surfaces were fabricated simply through SiC paper rubbing, and the wettability of the obtained surfaces was investigated thoroughly. The water contact angle increased firstly with the increasing particle size of the sandpaper, and then declined with further increase of the grits size, exhibiting a hydrophilic-hydrophobic-hydrophilic transition. The effect of surface geometric microstructure on the wetting behavior of aluminum alloy can be well rationalized in terms of the Cassie-Baxter model by considering the surface energy gradient. The present results not only enhance the in-depth understanding of the mechanism for the significant role of surface microstructure on the wettability of aluminum alloy, but also explore promising applications of versatile metallic surface in industries. © 2014 Elsevier B.V.


Xu K.,Huazhong University of Science and Technology | Xu K.,Beth Israel Deaconess Medical Center | Liu P.,Beth Israel Deaconess Medical Center | Wei W.,Beth Israel Deaconess Medical Center
Biochimica et Biophysica Acta - Reviews on Cancer | Year: 2014

mTOR (the mechanistic target of rapamycin) is an atypical serine/threonine kinase involved in regulating major cellular functions including growth and proliferation. Deregulation of the mTOR signaling pathway is one of the most commonly observed pathological alterations in human cancers. To this end, oncogenic activation of the mTOR signaling pathway contributes to cancer cell growth, proliferation and survival, highlighting the potential for targeting the oncogenic mTOR pathway members as an effective anti-cancer strategy. In order to do so, a thorough understanding of the physiological roles of key mTOR signaling pathway components and upstream regulators would guide future targeted therapies. Thus, in this review, we summarize available genetic mouse models for mTORC1 and mTORC2 components, as well as characterized mTOR upstream regulators and downstream targets, and assign a potential oncogenic or tumor suppressive role for each evaluated molecule. Together, our work will not only facilitate the current understanding of mTOR biology and possible future research directions, but more importantly, provide a molecular basis for targeted therapies aiming at key oncogenic members along the mTOR signaling pathway. © 2013 Elsevier B.V.


Zhang Y.,Huazhong University of Science and Technology | Yu M.,Dongguan Leke Electronic Company | Liu F.,Huazhong University of Science and Technology | Liu F.,Ryerson University | Kang Y.,Huazhong University of Science and Technology
IEEE Transactions on Power Electronics | Year: 2013

By regulating the inverter output current every switching cycle, instantaneous current-sharing control strategies are usually employed in paralleledmodular uninterruptible power supplies (UPSs). In this paper, virtual impedance, which is usually utilized in the droop method, is firstly introduced to the instantaneous current-sharing control strategy to achieve good load current-sharing performance. The instantaneous circulating current model of the paralleled system is developed and the circulating impedance is derived as well to clearly identify the intrinsic nature of unequal sharing of load current. By inserting the virtual impedance to the circulating impedance with the help of proper control strategy, good current-sharing capability can be obtained. The parallel inductor, e.g., coupled inductor, which is generally added at the output of each inverter to reduce the circulating current among modules, can be, therefore, eliminated, contributing to reduced weight, volume, and cost. In the meantime, the system output-voltage regulation performance, e.g., amplitude and waveform quality, is not affected by the introduction of the virtual impedance. The designation of the virtual impedance is provided and its implementation is simple but rather effective. Experimental results are also provided to verify the feasibility of the proposed method. © 2012 IEEE.


Li Y.,Huazhong University of Science and Technology | Li Y.,Beth Israel Deaconess Medical Center | Ye D.,Huazhong University of Science and Technology
Current Cancer Drug Targets | Year: 2010

Tumors are invariably less well-oxygenated than the normal tissues from which they arise. Hypoxia-inducible factor-1 (HIF-1), a key transcriptional regulator, plays a central role in the adaptation of tumor cells to hypoxia by activating the transcription of genes, which regulate several biological processes including angiogenesis, cell proliferation, survival, glucose metabolism and migration. The expression, activity and stability of HIF-1 are not only induced in response to reduced oxygen availability but also modulated through PI-3K, MAPKs, autocrine signaling pathways, E3 ubiquitin ligases, and other regulators. The regulators and effects of HIF-1 in cancer have intensively provided us a new clue for the HIF-1 targeting anticancer therapy. This review evaluates the HIF-1 structure, the regulation mechanisms, the functions in cancer and corresponding anticancer strategies. © 2010 Bentham Science Publishers Ltd.


News Article | November 16, 2016
Site: www.eurekalert.org

Researchers from Case Western Reserve University, Dayton Air Force Research Laboratory and China have developed a new dry adhesive that bonds in extreme temperatures--a quality that could make the product ideal for space exploration and beyond. The gecko-inspired adhesive loses no traction in temperatures as cold as liquid nitrogen or as hot as molten silver, and actually gets stickier as heat increases, the researchers report. The research, which builds on earlier development of a single-sided dry adhesive tape based on vertically aligned carbon nanotubes, is published in the journal Nature Communications. As far as the researchers know, no other dry adhesive is capable of working at such temperature extremes. Liming Dai, professor of macromolecular science and engineering at Case Western Reserve and an author of the study teamed with Ming Xu, a senior research associate at Case School of Engineering and visiting scholar from Huazhong University of Science and Technology; Feng Du, senior research associate in Case Western Reserve's Department of Macromolecular Science and Engineering; and Sabyasachi Ganguli and Ajit Roy, of the Materials and Manufacturing Directorate, Air Force Research Laboratory. Vertically aligned carbon nanotubes with tops bundled into nodes replicate the microscopic hairs on the foot of the wall-walking reptile and remain stable from -320 degrees Fahrenheit to 1,832 degrees, the scientists say. "When you have aligned nanotubes with bundled tops penetrating into the cavities of the surface, you generate sufficient van der Waal's forces to hold," Xu said. "The dry adhesive doesn't lose adhesion as it cools because the surface doesn't change. But when you heat the surface, the surface becomes rougher, physically locking the nanotubes in place, leading to stronger adhesion as temperatures increase." Because of the adhesive remains useful over such a wide range of temperatures, the inventors say it is ideally suited for use in space, where the shade can be frigid and exposure to the sun blazing hot. In addition to range, the bonding agent offers properties that could add to its utility. The adhesive conducts heat and electricity, and these properties also increase with temperature. "When applied as a double-sided sticky tape, the adhesive can be used to link electrical components together and also for electrical and thermal management," Roy said. "This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures," Dai said. "At room temperature, the double-sided carbon nanotube tape held as strongly as commercial tape on various rough surfaces, including paper, wood, plastic films and painted walls, showing potential use as conducting adhesives in home appliances and wall-climbing robots." In testing, a double-sided tape made with the carbon nanotubes (CNTs) applied between two layers of copper foil had an adhesive strength of about 37 newtons per cm-2 at room temperature, about the same as a commercial double-sided sticky tape. Unlike the commercial tape, which loses adhesion as it freezes or is heated, the CNT adhesive maintained its strength down to -320 degrees Fahrenheit. The adhesive strength more than doubled at 785 degrees Fahrenheit and was about six times as strong at 1891 degrees. Surprised by the increasing adhesive strength, the researchers used a scanning electron microscope to search for the cause. They found that, as the bundled nodes penetrate the surface cavities, the flexible nanotubes no longer remain vertically aligned but collapse into web-like structures. The action appears to enhance the van der Waal's forces due to an increased contact surface area with the collapsed nanotubes. Looking further, the researchers found that as the temperature increased above 392 degrees Fahrenheit, the surface of the copper foil became increasingly rough. The bundled ends and collapsed nanotubes appear to penetrate deeper into the heat-induced irregularities in the surface, increasing adhesion. The researchers dub this adhesion mechanism "nano-interlocking." The adhesive held strong during hundreds of temperature transition cycles between ambient temperature and -320 degrees then up to 1891 degrees and between the cold extreme and ambient temperature. Copper foil, which was used for many of the tests to demonstrate the potential for thermal management, is not unique. The surface of many other materials, including polymer films and other metal foils, roughen when heat is applied, making them good targets for this kind of adhesive, the team suggests. This work is mainly supported by the Department of Defense Air Force Office of Scientific Research Multidisciplinary Research Program of the University Research Initiative and the National Science Foundation.


News Article | February 22, 2017
Site: www.prweb.com

Ventiv Technology announced that Peter Yang has joined the company as chief information officer, effective immediately. The announcement was made by Bill Diaz, chief executive officer of Ventiv Technology.   In his role as chief information officer, Yang will be responsible for overseeing the DevOps of the company – architectire, development, data tools, and hosting. “Peter is a deeply technical and hands-on manager,” says Diaz. “He can roll up his sleeves to perform architectural design, code reviews, and help solve the most challenging application issues. I am deeply confident his RMIS/claims domain expertise will provide tremendous value to Ventiv.” Prior to beginning work at Ventiv, Yang spent four years as chief technology officer at FIS Insurance, leading development operations across a wide range of products across life & annuity, health insurance, property & casuality and financials. Prior to FIS, he spent 13 years holding engineering leadership roles at Marsh ClearSight. His expertise lies in building effective teams and architecting scalable, secure, cloud-friendly and high-performing enterprise applications and data/BI solutions. “I like the vision the team at Ventiv has and I am very excited to be a part of it,” says Yang. “I’m confident in our company’s dedication to delivering innovative and effective business solutions to our clients.” Yang holds a B.E. in biomedical engineering from Huazhong University of Science and Technology and an M.S./PhD in computer science and hearing science from Vanderbuilt University.


News Article | November 16, 2016
Site: phys.org

The gecko-inspired adhesive loses no traction in temperatures as cold as liquid nitrogen or as hot as molten silver, and actually gets stickier as heat increases, the researchers report. The research, which builds on earlier development of a single-sided dry adhesive tape based on vertically aligned carbon nanotubes, is published in the journal Nature Communications. As far as the researchers know, no other dry adhesive is capable of working at such temperature extremes. Liming Dai, professor of macromolecular science and engineering at Case Western Reserve and an author of the study teamed with Ming Xu, a senior research associate at Case School of Engineering and visiting scholar from Huazhong University of Science and Technology; Feng Du, senior research associate in Case Western Reserve's Department of Macromolecular Science and Engineering; and Sabyasachi Ganguli and Ajit Roy, of the Materials and Manufacturing Directorate, Air Force Research Laboratory. Vertically aligned carbon nanotubes with tops bundled into nodes replicate the microscopic hairs on the foot of the wall-walking reptile and remain stable from -320 degrees Fahrenheit to 1,832 degrees, the scientists say. "When you have aligned nanotubes with bundled tops penetrating into the cavities of the surface, you generate sufficient van der Waal's forces to hold," Xu said. "The dry adhesive doesn't lose adhesion as it cools because the surface doesn't change. But when you heat the surface, the surface becomes rougher, physically locking the nanotubes in place, leading to stronger adhesion as temperatures increase." Because of the adhesive remains useful over such a wide range of temperatures, the inventors say it is ideally suited for use in space, where the shade can be frigid and exposure to the sun blazing hot. In addition to range, the bonding agent offers properties that could add to its utility. The adhesive conducts heat and electricity, and these properties also increase with temperature. "When applied as a double-sided sticky tape, the adhesive can be used to link electrical components together and also for electrical and thermal management," Roy said. "This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures," Dai said. "At room temperature, the double-sided carbon nanotube tape held as strongly as commercial tape on various rough surfaces, including paper, wood, plastic films and painted walls, showing potential use as conducting adhesives in home appliances and wall-climbing robots." In testing, a double-sided tape made with the carbon nanotubes (CNTs) applied between two layers of copper foil had an adhesive strength of about 37 newtons per cm-2 at room temperature, about the same as a commercial double-sided sticky tape. Unlike the commercial tape, which loses adhesion as it freezes or is heated, the CNT adhesive maintained its strength down to -320 degrees Fahrenheit. The adhesive strength more than doubled at 785 degrees Fahrenheit and was about six times as strong at 1891 degrees. Surprised by the increasing adhesive strength, the researchers used a scanning electron microscope to search for the cause. They found that, as the bundled nodes penetrate the surface cavities, the flexible nanotubes no longer remain vertically aligned but collapse into web-like structures. The action appears to enhance the van der Waal's forces due to an increased contact surface area with the collapsed nanotubes. Looking further, the researchers found that as the temperature increased above 392 degrees Fahrenheit, the surface of the copper foil became increasingly rough. The bundled ends and collapsed nanotubes appear to penetrate deeper into the heat-induced irregularities in the surface, increasing adhesion. The researchers dub this adhesion mechanism "nano-interlocking." The adhesive held strong during hundreds of temperature transition cycles between ambient temperature and -320 degrees then up to 1891 degrees and between the cold extreme and ambient temperature. Copper foil, which was used for many of the tests to demonstrate the potential for thermal management, is not unique. The surface of many other materials, including polymer films and other metal foils, roughen when heat is applied, making them good targets for this kind of adhesive, the team suggests. Explore further: Nanotube adhesive sticks better than a gecko's foot


News Article | March 9, 2016
Site: www.nature.com

Researchers who wrote “design by the Creator” in a paper about the function of the human hand have triggered a debate over the quality of editing and peer review at the journal that published it — and ultimately retracted it. The paper by Cai-Hua Xiong of Huazhong University of Science and Technology in Wuhan, China, and his co-authors appeared in the journal PLoS ONE on 5 January1. But it came to prominence this week after its apparently creationist slant was flagged on Twitter, spawning the hashtags #Creatorgate and #HandofGod. James McInerney, who works on computational molecular evolution at the University of Manchester, UK, started the ball rolling when he tweeted: McInerney later provided a caveat, saying: “My original tweet was strong because creationism is a nuisance to me for 20+ years.” The paper's authors asked volunteers to perform a variety of tasks with their hands, and the researchers concluded that “our study can improve the understanding of the human hand and confirm that the mechanical architecture is the proper design by the Creator for dexterous performance of numerous functions following the evolutionary remodeling of the ancestral hand for millions of years”. It also includes the sentence, “Hand coordination should indicate the mystery of the Creator’s invention”. When contacted by Nature, Xiong said that he was discussing the issues raised with his co-authors and would respond as soon as possible. He added, “Indeed, we are not native speakers of English, and entirely lost the connotations of some words such as ‘Creator’. I am so sorry for that.” Other commenters expressed amazement that the paper had made it past peer review, and jokingly added that it should have included a citation to an appropriate deity. “There’s nothing wrong with the data that I can see, but the authors do make a surprising leap in the abstract and conclusion,” wrote biologist P. Z. Myers on his popular atheism and science blog Pharyngula. Others used the paper to discuss broader issues of journal quality, many responding to McInernery’s ‘joke’ comment about PLoS ONE. Some argued that it showed the importance and growing role of post-publication peer review, whereas others continued to criticize or defend the actions of the publisher. In online comments under the paper, various people who referred to themselves as PLOS editors expressed dismay that the paper had been published and threatened action, including resignations, if it was not retracted. Others said that the paper showed that peer-review standards at the journal were too low. (PLoS ONE accepts papers if reviewers find the science technically sound; it does not review for a paper’s importance or impact). Enrico Petretto, a genomics researcher at Imperial College London, wrote: “This is outrageous. If PLOS ONE does not do something about it, i.e., ask the authors to retract the paper, and in any case, if the paper isn’t retracted, my students, collaborators and I will have no choice but to refrain from considering (i.e., reading, reviewing and citing) papers published in PLOS ONE.” But others defended PLOS, pointing out other high-profile papers that had been published after peer review and had since been found to be problematic, including ‘arsenic life’ in Science and ‘the memory of water’ in Nature. Marc Robinson-Rechavi, an evolutionary biologist at the University of Lausanne in Switzerland, responded to McInernery’s tweet by saying “calling a journal which tries to publish honest reproducible science without concern for “impact” a joke is unjustified”. He told Nature “I do agree with more or less everyone that it is inappropriate to mention the creator with a capital C in the paper.” But, says Robinson-Rechavi, who is an academic editor at PLoS ONE, journals that publish many papers inevitably make mistakes: “no human process is error free”. What matters now is how PLOS responds to this error, he says. After the social-media storm, PLOS issued an initial statement to the media saying “PLOS has just been made aware of this issue and we are looking into it in depth. Our internal editors are reviewing the manuscript and will decide what course of action to take. The PLOS publishing team is also assessing its processes.” Later, on 2 March, the journal added an online statement to the paper: “A number of readers have concerns about sentences in the article that make references to a ‘Creator’. The PLOS ONE editors apologize that this language was not addressed internally or by the Academic Editor during the evaluation of the manuscript. We are looking into the concerns raised about the article with priority and will take steps to correct the published record.” Andrew David Thaler, a marine scientist and blogger at Southern Fried Science, took a different tack: On 3 March, the journal added in a further online statement that it would be retracting the article: "We have completed an evaluation of the history of the submission and received advice from two experts in our editorial board. Our internal review and the advice we have received have confirmed the concerns about the article and revealed that the peer review process did not adequately evaluate several aspects of the work. In light of the concerns identified, the PLOS ONE editors have decided to retract the article, the retraction is being processed and will be posted as soon as possible. We apologize for the errors and oversight leading to the publication of this paper."


News Article | November 17, 2016
Site: www.cemag.us

Researchers from Case Western Reserve University, Dayton Air Force Research Laboratory, and China have developed a new dry adhesive that bonds in extreme temperatures — a quality that could make the product ideal for space exploration and beyond. The gecko-inspired adhesive loses no traction in temperatures as cold as liquid nitrogen or as hot as molten silver, and actually gets stickier as heat increases, the researchers report. The research, which builds on earlier development of a single-sided dry adhesive tape based on vertically aligned carbon nanotubes, is published in the journal Nature Communications. As far as the researchers know, no other dry adhesive is capable of working at such temperature extremes. Liming Dai, professor of macromolecular science and engineering at Case Western Reserve and an author of the study teamed with Ming Xu, a senior research associate at Case School of Engineering and visiting scholar from Huazhong University of Science and Technology; Feng Du, senior research associate in Case Western Reserve’s Department of Macromolecular Science and Engineering; and Sabyasachi Ganguli and Ajit Roy, of the Materials and Manufacturing Directorate, Air Force Research Laboratory. Vertically aligned carbon nanotubes with tops bundled into nodes replicate the microscopic hairs on the foot of the wall-walking reptile and remain stable from -320 degrees Fahrenheit to 1,832 degrees, the scientists say. “When you have aligned nanotubes with bundled tops penetrating into the cavities of the surface, you generate sufficient van der Waal’s forces to hold,” Xu says. “The dry adhesive doesn’t lose adhesion as it cools because the surface doesn’t change. But when you heat the surface, the surface becomes rougher, physically locking the nanotubes in place, leading to stronger adhesion as temperatures increase.” Because the adhesive remains useful over such a wide range of temperatures, the inventors say it is ideally suited for use in space, where the shade can be frigid and exposure to the sun blazing hot. In addition to range, the bonding agent offers properties that could add to its utility. The adhesive conducts heat and electricity, and these properties also increase with temperature. “When applied as a double-sided sticky tape, the adhesive can be used to link electrical components together and also for electrical and thermal management,” Roy says. “This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures,” Dai says. “At room temperature, the double-sided carbon nanotube tape held as strongly as commercial tape on various rough surfaces, including paper, wood, plastic films and painted walls, showing potential use as conducting adhesives in home appliances and wall-climbing robots.”


News Article | November 16, 2016
Site: www.rdmag.com

Researchers from Case Western Reserve University, Dayton Air Force Research Laboratory and China have developed a new dry adhesive that bonds in extreme temperatures--a quality that could make the product ideal for space exploration and beyond. The gecko-inspired adhesive loses no traction in temperatures as cold as liquid nitrogen or as hot as molten silver, and actually gets stickier as heat increases, the researchers report. The research, which builds on earlier development of a single-sided dry adhesive tape based on vertically aligned carbon nanotubes, is published in the journal Nature Communications. As far as the researchers know, no other dry adhesive is capable of working at such temperature extremes. Liming Dai, professor of macromolecular science and engineering at Case Western Reserve and an author of the study teamed with Ming Xu, a senior research associate at Case School of Engineering and visiting scholar from Huazhong University of Science and Technology; Feng Du, senior research associate in Case Western Reserve's Department of Macromolecular Science and Engineering; and Sabyasachi Ganguli and Ajit Roy, of the Materials and Manufacturing Directorate, Air Force Research Laboratory. Vertically aligned carbon nanotubes with tops bundled into nodes replicate the microscopic hairs on the foot of the wall-walking reptile and remain stable from -320 degrees Fahrenheit to 1,832 degrees, the scientists say. "When you have aligned nanotubes with bundled tops penetrating into the cavities of the surface, you generate sufficient van der Waal's forces to hold," Xu said. "The dry adhesive doesn't lose adhesion as it cools because the surface doesn't change. But when you heat the surface, the surface becomes rougher, physically locking the nanotubes in place, leading to stronger adhesion as temperatures increase." Because of the adhesive remains useful over such a wide range of temperatures, the inventors say it is ideally suited for use in space, where the shade can be frigid and exposure to the sun blazing hot. In addition to range, the bonding agent offers properties that could add to its utility. The adhesive conducts heat and electricity, and these properties also increase with temperature. "When applied as a double-sided sticky tape, the adhesive can be used to link electrical components together and also for electrical and thermal management," Roy said. "This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures," Dai said. "At room temperature, the double-sided carbon nanotube tape held as strongly as commercial tape on various rough surfaces, including paper, wood, plastic films and painted walls, showing potential use as conducting adhesives in home appliances and wall-climbing robots." In testing, a double-sided tape made with the carbon nanotubes (CNTs) applied between two layers of copper foil had an adhesive strength of about 37 newtons per cm-2 at room temperature, about the same as a commercial double-sided sticky tape. Unlike the commercial tape, which loses adhesion as it freezes or is heated, the CNT adhesive maintained its strength down to -320 degrees Fahrenheit. The adhesive strength more than doubled at 785 degrees Fahrenheit and was about six times as strong at 1891 degrees. Surprised by the increasing adhesive strength, the researchers used a scanning electron microscope to search for the cause. They found that, as the bundled nodes penetrate the surface cavities, the flexible nanotubes no longer remain vertically aligned but collapse into web-like structures. The action appears to enhance the van der Waal's forces due to an increased contact surface area with the collapsed nanotubes. Looking further, the researchers found that as the temperature increased above 392 degrees Fahrenheit, the surface of the copper foil became increasingly rough. The bundled ends and collapsed nanotubes appear to penetrate deeper into the heat-induced irregularities in the surface, increasing adhesion. The researchers dub this adhesion mechanism "nano-interlocking." The adhesive held strong during hundreds of temperature transition cycles between ambient temperature and -320 degrees then up to 1891 degrees and between the cold extreme and ambient temperature. Copper foil, which was used for many of the tests to demonstrate the potential for thermal management, is not unique. The surface of many other materials, including polymer films and other metal foils, roughen when heat is applied, making them good targets for this kind of adhesive, the team suggests.


News Article | November 17, 2016
Site: www.gizmag.com

Researchers have developed a new dry adhesive that not only bonds in extreme temperatures, it even gets stronger as the heat goes up. The gecko-inspired material maintains its hold in extreme cold and actually gets stickier in extreme heat. Building on previous research, a team of engineers from Case Western Reserve University and Dayton Air Force Research Laboratory created a double-sided tape made of carbon nanotubes that they claim would lose no traction whether applied to cold liquid nitrogen or hot molten silver. The nanotubes that make up the adhesive are vertically aligned and bundled into nodes similar to the microscopic hairs on a gecko's foot pads that allow it to walk up walls. A number of other adhesives and grippers have been derived from the same inspiration, but this new invention has some notable qualities. Most commercial tapes you might buy in a store lose their stickiness as they freeze or heat up, but the new carbon nanotube adhesive stayed just as strong down to -320 degrees Fahrenheit (-196 Celsius), doubled strength at 785 degrees Fahrenheit (418 C) and increased its grip six-fold at 1,891 (1,033 C) degrees. The researchers used a high-powered scanning electron microscope to observe what gives the adhesive its unusual increasing strength. They found that the nanotubes collapse into web-like structures that increase the contact surface area with a material, in turn enhancing the "sticky" van der Waal's forces. Increases in temperature can make the surface the adhesive is applied to more rough, allowing the nanotubes to penetrate deeper into the irregularities and hold even tighter. "The dry adhesive doesn't lose adhesion as it cools because the surface doesn't change," explains Ming Xu, a senior research associate at Case School of Engineering and visiting scholar from Huazhong University of Science and Technology. "But when you heat the surface, the surface becomes rougher, physically locking the nanotubes in place, leading to stronger adhesion as temperatures increase." The resilience of the new adhesive could make it especially useful in space, where temperatures can swing by several hundreds of degrees between the shade and direct sunlight. It also conducts heat and electricity, adding to its potential utility. "This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures," said study author and Case Western Reserve professor Liming Dai said. "At room temperature, the double-sided carbon nanotube tape held as strongly as commercial tape on various rough surfaces, including paper, wood, plastic films and painted walls, showing potential use as conducting adhesives in home appliances and wall-climbing robots."


News Article | November 18, 2016
Site: www.sciencedaily.com

Researchers from Case Western Reserve University, Dayton Air Force Research Laboratory and China have developed a new dry adhesive that bonds in extreme temperatures -- a quality that could make the product ideal for space exploration and beyond. The gecko-inspired adhesive loses no traction in temperatures as cold as liquid nitrogen or as hot as molten silver, and actually gets stickier as heat increases, the researchers report. The research, which builds on earlier development of a single-sided dry adhesive tape based on vertically aligned carbon nanotubes, is published in the journal Nature Communications. As far as the researchers know, no other dry adhesive is capable of working at such temperature extremes. Liming Dai, professor of macromolecular science and engineering at Case Western Reserve and an author of the study teamed with Ming Xu, a senior research associate at Case School of Engineering and visiting scholar from Huazhong University of Science and Technology; Feng Du, senior research associate in Case Western Reserve's Department of Macromolecular Science and Engineering; and Sabyasachi Ganguli and Ajit Roy, of the Materials and Manufacturing Directorate, Air Force Research Laboratory. Vertically aligned carbon nanotubes with tops bundled into nodes replicate the microscopic hairs on the foot of the wall-walking reptile and remain stable from -320 degrees Fahrenheit to 1,832 degrees, the scientists say. "When you have aligned nanotubes with bundled tops penetrating into the cavities of the surface, you generate sufficient van der Waal's forces to hold," Xu said. "The dry adhesive doesn't lose adhesion as it cools because the surface doesn't change. But when you heat the surface, the surface becomes rougher, physically locking the nanotubes in place, leading to stronger adhesion as temperatures increase." Because of the adhesive remains useful over such a wide range of temperatures, the inventors say it is ideally suited for use in space, where the shade can be frigid and exposure to the sun blazing hot. In addition to range, the bonding agent offers properties that could add to its utility. The adhesive conducts heat and electricity, and these properties also increase with temperature. "When applied as a double-sided sticky tape, the adhesive can be used to link electrical components together and also for electrical and thermal management," Roy said. "This adhesive can thus be used as connecting materials to enhance the performance of electronics at high temperatures," Dai said. "At room temperature, the double-sided carbon nanotube tape held as strongly as commercial tape on various rough surfaces, including paper, wood, plastic films and painted walls, showing potential use as conducting adhesives in home appliances and wall-climbing robots." In testing, a double-sided tape made with the carbon nanotubes (CNTs) applied between two layers of copper foil had an adhesive strength of about 37 newtons per cm-2 at room temperature, about the same as a commercial double-sided sticky tape. Unlike the commercial tape, which loses adhesion as it freezes or is heated, the CNT adhesive maintained its strength down to -320 degrees Fahrenheit. The adhesive strength more than doubled at 785 degrees Fahrenheit and was about six times as strong at 1891 degrees. Surprised by the increasing adhesive strength, the researchers used a scanning electron microscope to search for the cause. They found that, as the bundled nodes penetrate the surface cavities, the flexible nanotubes no longer remain vertically aligned but collapse into web-like structures. The action appears to enhance the van der Waal's forces due to an increased contact surface area with the collapsed nanotubes. Looking further, the researchers found that as the temperature increased above 392 degrees Fahrenheit, the surface of the copper foil became increasingly rough. The bundled ends and collapsed nanotubes appear to penetrate deeper into the heat-induced irregularities in the surface, increasing adhesion. The researchers dub this adhesion mechanism "nano-interlocking." The adhesive held strong during hundreds of temperature transition cycles between ambient temperature and -320 degrees then up to 1891 degrees and between the cold extreme and ambient temperature. Copper foil, which was used for many of the tests to demonstrate the potential for thermal management, is not unique. The surface of many other materials, including polymer films and other metal foils, roughen when heat is applied, making them good targets for this kind of adhesive, the team suggests.


News Article | March 4, 2016
Site: www.techtimes.com

A scientific paper on the movement of the human hand stirred controversy as it referenced a “Creator” throughout, including sections such as “design by the Creator.” It triggered a debate on Twitter and the scientific community over the quality of editing and peer review at the journal that released, and eventually retracted it. The paper, authored by Cai-Hua Xiong of Huazhong University of Science and Technology in China and three other researchers, was published in PLOS ONE last Jan. 5. Titled “Biomechanical Characteristic Of Hand Coordination In Grasping Activities Of Daily Living,” the paper delved on the mechanics of how people grasp things, measuring hand movements of 30 subjects. “Hand coordination should indicate the mystery of the Creator’s invention,” says the paper, which also concluded that the “mechanical architecture [of the hand] is the proper design by the Creator for dexterous performance of numerous functions.” On Twitter, computational molecular evolution expert James McInerney of the University of Manchester criticized the piece and dubbed the journal “a joke.” He said he published a strong tweet because creationism has been a “nuisance” to him for more than 20 years now. The apparently creationist slant of the paper got Twitter all abuzz with the hashtags #Creatorgate as well as #HandofGod. In response to an inquiry from Nature, Xiong said the authors are now discussing the issues raised. “Indeed, we are not native speakers of English, and entirely lost the connotations of some words such as ‘Creator.’ I am so sorry for that,” he explains. In the comments section, the authors made the same acknowledgment, citing translational errors – instead of a belief in intelligent design – for the “Creator” references. In a statement appearing in the comments, PLOS ONE’s staff also apologized for the language pertaining to a “Creator” in the research, admitting it was not addressed during review and evaluation. They said they are looking into the issues raised and that they would take steps to correct the published piece. “We apologize for the errors and oversight leading to the publication of the paper,” the journal said. It also announced on March 3 that it is retracting the article. On his blog, biologist PZ Myers said that where there is inherently nothing wrong with the paper’s data, its researchers made “a surprising leap” in the abstract as well as conclusion. Genomics researcher Enrico Petretto of Imperial College London was more straightforward in his comment, saying he and his students and collaborators would be left with no choice but to stop reading, reviewing, and citing PLOS ONE studies if no retraction will be made. David Klinghoffer, a senior fellow at the Discovery Institute in Seattle, argued that the paper may not exactly be bred by creationist research, with the authors assuming “evolutionary remodeling” of the hand for millions of years. He also speculated on a language issue, as the authors as well as the editor, Renzhi Han, are all Chinese. PLOS ONE academic editor and evolutionary biologist Marc Robinson-Rechavi added that no human process is spared from errors – the point, he said, is how the journal responds to the mistake made.


News Article | April 10, 2016
Site: www.nanotech-now.com

Home > Press > Catalyst could make production of key chemical more eco-friendly Abstract: The world has more carbon dioxide than it needs, and a team of Brown University chemists has come up with a potential way to put some of it to good use. The researchers developed a new composite catalyst using nitrogen-rich graphene dotted with copper nanoparticles. A study, published in the journal Nano Energy, showed that the new catalyst can efficiently and selectively convert carbon dioxide to ethylene, one of the world's most important commodity chemicals. Ethylene is used to make plastics, construction materials and other products. Chemical companies produce it by the millions of tons each year using processes that usually involve fossil fuels. If excess carbon dioxide can be used to make ethylene, it could help make the chemical industry more sustainable and eco-friendly. "We hope that this new catalyst could be a step toward a greener way to produce ethylene," said Shouheng Sun, a professor of chemistry and engineering at Brown, whose research team developed the catalyst. "There is much more work to be done to bring such a process to an industrial scale, but this is a start." Selectivity is key Carbon dioxide is a stable form of carbon, and breaking it down into active carbon forms is no easy task. While some catalysts can do the job, they generally do not have good selectivity, meaning they create a variety of different reaction products. "Most other techniques produce ethylene, methane, carbon monoxide -- all kinds of things that you would then have to separate," Sun said. "We wanted something that could be more selective." Qing Li, a former postdoctoral fellow in Sun's lab and now a professor at Huazhong University of Science and Technology in China, thought a catalyst that combines copper nanoparticles with graphene might be effective. Sun's lab had previously shown that metal nanoparticles, when tuned to the right size, could have increased reactivity. Graphene, one-atom-thick sheets of carbon, has also been shown to increase catalyst reactivity. Li, the new study's lead author, experimented with copper nanoparticles deposited on several different graphene surfaces -- pure graphene, graphene oxide and graphene doped with nitrogen in various forms. Nitrogen doping is a process of introducing nitrogen atoms into the lattice of carbon atoms that make up graphene. The study showed that seven-nanometer copper particles deposited on graphene doped with pyridinic nitrogen (an arrangement that causes nitrogen atoms to be bonded to two carbon atoms) had the best performance. That arrangement had selectivity for ethylene of 79 percent, significantly higher than other approaches, according to the study. "Synergistic effect" It is not entirely clear what about the new catalyst is responsible for its performance, but Li and Sun propose a few ideas. "It's probably a synergistic effect," Li said. "The pyridinic nitrogen helps to anchor the copper nanoparticles and change the electronic environment around them, which changes the reaction pathway to selectively produce ethylene." Sun noted that carbon dioxide can serve as a weak Lewis acid -- a compound that accepts electrons from donor compounds. Pyridinic nitrogen in the nitrogen-doped graphene forms a Lewis base center. "We think that the presence of this Lewis base center helps to draw more carbon dioxide close to the copper for the observed catalysis," Sun said. The researchers plan to continue work with the new catalyst, possibly using it in tandem with other catalysts to produce different reaction products. "The possibilities are exciting," Sun said. ### Other authors on the paper were Wenlei Zhu, Jiaju Fu and Hongyi Zhang from Brown, and Gang Wu from SUNY Buffalo. The work was supported by the U.S. Army Research Laboratory and the U.S. Army Research Office (W911NF-15-1-0147 and W911NF-11-1-0353), and the National Science Foundation ( CHE-1240020). For more information, please click If you have a comment, please us. Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.


Wu J.,Wuhan University | Ding X.-H.,Huazhong University of Science and Technology
Scientometrics | Year: 2013

Scientists generally do scientific collaborations with one another and sometimes change their affiliations, which leads to scientific mobility. This paper proposes a recursive reinforced name disambiguation method that integrates both coauthorship and affiliation information, especially in cases of scientific collaboration and mobility. The proposed method is evaluated using the dataset from the Thomson Reuters Scientific "Web of Science". The probability of recall and precision of the algorithm are then analyzed. To understand the effect of the name ambiguation on the h-index and g-index before and after the name disambiguation, calculations of their distribution are also presented. Evaluation experiments show that using only the affiliation information in the name disambiguation achieves better performance than that using only the coauthorship information; however, our proposed method that integrates both the coauthorship and affiliation information can control the bias in the name ambiguation to a higher extent. © 2013 Akadémiai Kiadó, Budapest, Hungary.


Wang Z.,University of Minnesota | Deng S.,Huazhong University of Science and Technology | Ye Y.,Stanford University
Operations Research | Year: 2014

We consider a retailer selling a single product with limited on-hand inventory over a finite selling season. Customer demand arrives according to a Poisson process, the rate of which is influenced by a single action taken by the retailer (such as price adjustment, sales commission, advertisement intensity, etc.). The relationship between the action and the demand rate is not known in advance. However, the retailer is able to learn the optimal action on the fly as she maximizes her total expected revenue based on the observed demand reactions. Using the pricing problem as an example, we propose a dynamic learning-while-doing algorithm that only involves function value estimation to achieve a near-optimal performance. Our algorithm employs a series of shrinking price intervals and iteratively tests prices within that interval using a set of carefully chosen parameters. We prove that the performance of our algorithm is among the best of all possible algorithms in terms of the asymptotic regret (the relative loss compared to the full information optimal solution). Our result closes the performance gaps between parametric and nonparametric learning and between the post-price mechanism and the customer-bidding mechanism. Important managerial insight from this research is that the values of information on both the parametric form of the demand function as well as each customer's exact reservation price are less important than prior literature suggests. Our results also suggest that firms would be better off to perform dynamic learning and action concurrently rather than sequentially. © 2014 INFORMS.


Liu S.,Xi'an Jiaotong University | Wang L.,Huazhong University of Science and Technology
International Journal of Project Management | Year: 2016

The relationship between managerial control and performance has been extensively investigated in literature. However, in the context of medical information systems (IS) projects, this topic has received little attention. Furthermore, the integrated effects of organizational environment and team risks, as well as managerial controls on the performance of medical IS projects have never been examined. The present study attempts to bridge these gaps using data on 195 medical IS projects from 160 hospitals. Our empirical results demonstrate that behavior, outcome, and clan controls positively affect the performance of medical IS projects. By contrast, self-control is insignificantly related to performance. This finding reveals that in medical IS projects, the effectiveness of managerial controls varies. Not all control modes significantly influence the performance of medical IS projects. Effective control modes should therefore be prioritized over ineffective control modes for such complex projects. Moreover, organizational environment and team risks diminish the effects of behavior, outcome and clan controls on performance in medical IS projects, which implies that project performance relies on the integrative influence of controls and risks, and the exercise of control should consider the mitigation of risks from both client and development team sides in medical IS projects. © 2015 Elsevier Ltd and Association for Project Management and the International Project Management Association.


Shao Z.,Wuhan University | Liu J.,Wuhan University | Cheng Q.,Huazhong University of Science and Technology
Applied Optics | Year: 2012

Aiming at the differences of physical characteristics between infrared sensors and visible ones, we introduce the focus measure operators into the curvelet domain in order to propose a novel image fusion method. First, the fast discrete curvelet transform is performed on the original images to obtain the coefficient subbands in different scales and various directions, and the focus measure values are calculated in each coefficient subband. Then, the local variance weighted strategy is employed to the lowfrequency coefficient subbands for the purpose of maintaining the low-frequency information of the infrared image and adding the low-frequency features of the visible image to the fused image; meanwhile, the fourth-order correlation coefficient match strategy is performed to the high-frequency coefficient subbands to select the suitable high-frequency information. Finally, the fused image can be obtained through the inverse curvelet transform. The practical experiments indicate that the presented method can integrate more useful information from the original images, and the fusion performance is proved to be much better than the traditional methods based on the wavelet, curvelet, and pyramids. © 2012 Optical Society of America.


Tu L.,Huazhong University of Science and Technology | Huang C.-M.,National Cheng Kung University
IEEE Transactions on Vehicular Technology | Year: 2010

Collision warning is one of the most important functions of a vehicle safety system. The emergence and expansion of the applications of positioning techniques and dedicated short-range communication (DSRC) have promoted the collision warning system evolution from a simple ranging-sensor-based system to a cooperative system. Differing from prior work that relied heavily on the e-Map, high-accuracy differential Global Positioning System (DGPS), or advanced car features like the controller area network (CAN) bus, this paper proposes Forwards, i.e., a map-free intersection collision-warning system for all road patterns with lower requirement and lower cost accessories. Forwards employs a triple Kalman filter (tri-KF)-based estimator that integrates GPS and external inertial sensor measurement to provide calibrated motion state information (MSI) such as position, velocity, and acceleration of the vehicle. Each vehicle then adaptively broadcasts its own MSI via the DSRC-based protocol. Using the steady-state maneuvering model, short-term trajectories of local and neighboring vehicles are further predicted, based on their current MSI. Collision-detection algorithms are then designed based on the model of finding the minimum distance of vehicles' future trajectories, and hierarchical warnings are given upon different criteria. Simulation results show that our approach outperforms the referenced approach in successful warning ratio and requires far fewer accessories and external conditions than the other referenced approaches. © 2006 IEEE.


Lei W.-H.,University of Nevada, Las Vegas | Lei W.-H.,Huazhong University of Science and Technology | Zhang B.,University of Nevada, Las Vegas
Astrophysical Journal Letters | Year: 2011

Recently, a hard X-ray transient event, SwJ1644+57, was discovered by the Swift satellite. It likely marks the onset of a relativistic jet from a supermassive black hole (BH), possibly triggered by a tidal disruption event (TDE). Another candidate in the same category, SwJ2058+05, was also reported. The low event rate suggests that only a small fraction of TDEs launch relativistic jets. A common speculation is that these rare events are related to rapidly spinning BHs. We attribute jet launching to the Blandford-Znajek mechanism and use the available data to constrain the BH spin parameter for the two events. It is found that the two BHs indeed carry a moderate to high spin, suggesting that BH spin is likely the crucial factor behind the SwJ1644+57-like events. © 2011. The American Astronomical Society. All rights reserved.


Chen L.,Huazhong University of Science and Technology | Zhang T.,Huazhong University of Science and Technology | Li X.,McMaster University | Wang G.,Wuhan University
Optics Express | Year: 2013

Considering the propagation of surface plasmon polaritons (SPPs) supported by a graphene monolayer can be effectively controlled via electrostatic gating, we propose a graphene monolayer on a graded silicongrating substrate with dielectric spacer as an interlayer for plasmonic rainbow trapping in the infrared domain. Since the dispersive relation of SPPs is dependent on the width of dielectric spacer filling the silicon grating, the guided SPPs at different frequencies can be localized at different positions along the graphene surface, associated with the period of silicon grating. The group velocity of slow SPPs can be made to be several hundred times smaller than light velocity in vacuum. We also predict the capability of completely releasing the trapped SPPs by dynamically tuning the chemical potential of graphene by means of gate voltage. The advantages of such a structure include compact size, wide frequency tunability, and compatibility with current micro/nanofabrication, which holds great promise for applications in graphene-based optoelectronic devices. © 2013 Optical Society of America.


Liu S.,Wuhan University | Wang L.,Huazhong University of Science and Technology
International Journal of Project Management | Year: 2014

Successfully managing the risks of information technology projects continues to be a central problem for organizations regardless of whether the project is outsourced or not. While a plethora of studies has examined the effects of risks on performance, majority fail to distinguish the sourcing characteristics of the projects investigated. Furthermore, little is known about the joint effects of strategic importance and the risk on system performance across internal and outsourced projects. Based on data collected from 77 internal projects and 51 outsourced projects, we find that social subsystem and project management risks are negatively associated with system performance in both internal and outsourced projects. However, technical subsystem risk negatively affects performance only in internal projects. While social subsystem risk exerts greater influence on system performance in outsourced projects than in internal projects, the technical subsystem risk has greater effect on performance in internal than that in outsourced projects. Moreover, the effect of project management risk is not different in both types of projects. In addition, strategic importance moderates the relationship between risks and performance. The negative impact of risks on performance is greater in projects that are more strategic. Strategies are proposed to reduce the complexity and potential conflicts inherent to strategic projects because these characteristics may amplify a risk's impact. © 2014.


Cao N.,Hubei University | Su J.,Huazhong University of Science and Technology | Luo W.,Hubei University | Cheng G.,Hubei University
International Journal of Hydrogen Energy | Year: 2014

Ru@Ni core-shell nanoparticles (NPs) supported on graphene have been synthesized by one-step in situ co-reduction of aqueous solution of ruthenium (III) chloride, nickel (II) chloride, and graphene oxide (GO) with ammonia borane (AB) as the reducing agent under ambient condition. The as-synthesized NPs exhibit much higher catalytic activity for hydrolytic dehydrogenation of AB than the monometallic, bimetallic alloy (RuNi/graphene), and graphene-free core-shell (Ru@Ni) counterparts. Additionally, the Ru@Ni/graphene NPs facilitate the hydrolysis of AB, with the turnover frequency (TOF) value of 340 mol H 2 min-1 (mol Ru)-1, which is among the highest value reported on Ru-based NPs so far, and even higher than the reversed Ni@Ru NPs. Furthermore, the as-prepared NPs exert satisfied durable stability and magnetically recyclability for the hydrolytic dehydrogenation of AB and methylamine borane (MeAB). Moreover, this simple synthetic method can be extended to other Ru-based bimetallic core-shell systems for more applications. Copyright © 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.


Jiang H.,Huazhong University of Science and Technology | Jin S.,Case Western Reserve University | Wang C.,NEC Laboratories America Inc.
IEEE Transactions on Parallel and Distributed Systems | Year: 2011

For many applications in wireless sensor networks (WSNs), users may want to continuously extract data from the networks for analysis later. However, accurate data extraction is difficultit is often too costly to obtain all sensor readings, as well as not necessary in the sense that the readings themselves only represent samples of the true state of the world. Clustering and prediction techniques, which exploit spatial and temporal correlation among the sensor data provide opportunities for reducing the energy consumption of continuous sensor data collection. Integrating clustering and prediction techniques makes it essential to design a new data collection scheme, so as to achieve network energy efficiency and stability. We propose an energy-efficient framework for clustering-based data collection in wireless sensor networks by integrating adaptively enabling/disabling prediction scheme. Our framework is clustering based. A cluster head represents all sensor nodes in the cluster and collects data values from them. To realize prediction techniques efficiently in WSNs, we present adaptive scheme to control prediction used in our framework, analyze the performance tradeoff between reducing communication cost and limiting prediction cost, and design algorithms to exploit the benefit of adaptive scheme to enable/disable prediction operations. Our framework is general enough to incorporate many advanced features and we show how sleep/awake scheduling can be applied, which takes our framework approach to designing a practical algorithm for data aggregation: it avoids the need for rampant node-to-node propagation of aggregates, but rather it uses faster and more efficient cluster-to-cluster propagation. To the best of our knowledge, this is the first work adaptively enabling/disabling prediction scheme for clustering-based continuous data collection in sensor networks. Our proposed models, analysis, and framework are validated via simulation and comparison with competing techniques. © 2011 IEEE.


Xu L.,Huazhong University of Science and Technology | Shi Z.-G.,Wuhan University | Feng Y.-Q.,Wuhan University
Analytical and Bioanalytical Chemistry | Year: 2011

In this review the focus is on application of porous monoliths to miniaturized extraction of biological analysis, with emphasis on porous monolithic materials and different miniaturized extraction formats. The general approaches used to synthesize organic polymer and silica monolithic materials are highlighted, and their properties and applicability are described and compared. Several extraction formats, including in-tube microextraction, chip-based microextraction, tip-based microextraction, among others, are reviewed in depth. © 2010 Springer-Verlag.


Ni Z.,University of Rhode Island | He H.,University of Rhode Island | Wen J.,Huazhong University of Science and Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

In this paper, we present a new adaptive dynamic programming approach by integrating a reference network that provides an internal goal representation to help the systems learning and optimization. Specifically, we build the reference network on top of the critic network to form a dual critic network design that contains the detailed internal goal representation to help approximate the value function. This internal goal signal, working as the reinforcement signal for the critic network in our design, is adaptively generated by the reference network and can also be adjusted automatically. In this way, we provide an alternative choice rather than crafting the reinforcement signal manually from prior knowledge. In this paper, we adopt the online action-dependent heuristic dynamic programming (ADHDP) design and provide the detailed design of the dual critic network structure. Detailed Lyapunov stability analysis for our proposed approach is presented to support the proposed structure from a theoretical point of view. Furthermore, we also develop a virtual reality platform to demonstrate the real-time simulation of our approach under different disturbance situations. The overall adaptive learning performance has been tested on two tracking control benchmarks with a tracking filter. For comparative studies, we also present the tracking performance with the typical ADHDP, and the simulation results justify the improved performance with our approach. © 2012 IEEE.


Ma J.,Wuhan University | Zhao J.,Huazhong University of Science and Technology | Ma Y.,Wuhan University | Tian J.,Huazhong University of Science and Technology
Pattern Recognition | Year: 2015

Registration of multi-sensor data (particularly visible color sensors and infrared sensors) is a prerequisite for multimodal image analysis such as image fusion. Typically, the relationships between image pairs are modeled by rigid or affine transformations. However, this cannot produce accurate alignments when the scenes are not planar, for example, face images. In this paper, we propose a regularized Gaussian fields criterion for non-rigid registration of visible and infrared face images. The key idea is to represent an image by its edge map and align the edge maps by a robust criterion with a non-rigid model. We model the transformation between images in a reproducing kernel Hilbert space and a sparse approximation is applied to the transformation to avoid high computational complexity. Moreover, a coarse-to-fine strategy by applying deterministic annealing is used to overcome local convergence problems. The qualitative and quantitative comparisons on two publicly available databases demonstrate that our method significantly outperforms the state-of-the-art method with an affine model. As a result, our method will be beneficial for fusion-based face recognition. © 2014 Elsevier Ltd. All rights reserved.


Yang L.,Hubei University | Su J.,Huazhong University of Science and Technology | Meng X.,Hubei University | Luo W.,Hubei University | Cheng G.,Hubei University
Journal of Materials Chemistry A | Year: 2013

Well dispersed magnetically recyclable trimetallic core-shell Ag@CoNi nanoparticles (NPs) supported on graphene have been synthesized via a facile one-step in situ procedure using methylamine borane (MeAB) as the reducing agent. The as-synthesized NPs exhibit much higher catalytic activities for hydrolytic dehydrogenation of ammonia borane (AB) than the monometallic, bimetallic, trimetallic alloy (AgCoNi/graphene), and graphene free (Ag@CoNi) counterparts. Moreover, compared with NaBH4 and AB, the weaker reducing agent MeAB has much better control during the synthesis of the graphene supported Ag@CoNi NPs, which resulted in the highest catalytic activity. Kinetic studies indicate that the catalytic hydrolysis of AB by the Ag@CoNi/graphene NPs is first order, with the activation energy measured to be 36.15 kJ mol-1. Furthermore, the as-prepared NPs exert good catalytic activities and recycle stabilities towards the hydrolysis of AB and MeAB. Hence, this general method indicates that MeAB can be used as both a potential hydrogen storage material and an efficient reducing agent, and can be easily extended to facile preparation of other graphene supported multi-metal NPs. © 2013 The Royal Society of Chemistry.


Zou Y.-C.,Hebrew University of Jerusalem | Zou Y.-C.,Huazhong University of Science and Technology | Piran T.,Hebrew University of Jerusalem
Monthly Notices of the Royal Astronomical Society | Year: 2010

While it is generally agreed that the emitting regions in gamma-ray bursts move ultra-relativistically towards the observer, different estimates of the initial Lorentz factors, Γ0, lead to different at times conflicting estimates. We show here that the quiet periods in which the signals goes down below the instrumental thresholds put strong upper limits on the values of Γ0. According to the standard internal-external shock model, an external shock should develop during the prompt stage. This external shock radiates in the hard X-rays to soft gamma-rays bands and this emission should be seen as a smooth background signal. The observed deep minima indicate that this contribution is negligible. This limits, in turn, Γ0. We obtain upper limits on Γ0 for several bursts with typical values around hundreds. We compare these values with those obtained by the other methods, which typically yield lower limits. The results are marginally consistent leaving only a narrow range of allowed values for Γ0. © 2009 The Authors. Journal compilation © 2009 RAS.


Hu Y.,Wuhan University | Li C.,Wuhan University | Shen W.,Huazhong University of Science and Technology
Neuropathology | Year: 2014

Alzheimer's disease (AD) is a progressive, neurodegenerative disease, characterized by excessive accumulation of amyloid-beta (Aβ) and activation of microglia cells and astrocytes. In this research, we evaluated whether gastrodin, an active component isolated from the rhizome of Gastrodia elata, has neuroprotective effects in a mouse model of AD, Tg2576 mice. Treatment of gastrodin (60mg/kg for 15 days) significantly improved memory impairments in the Morris water maze test and probe test. Moreover, immunohistochemical and ELISA results indicated that gastrodin significantly attenuated Aβ deposition and glial activation in brains of these transgenic mice. These findings suggested that gastrodin exerted neuroprotective activity via anti-inflammatory and anti-amyloidogenic effects and that gastrodin may be a potential option for AD therapy. © 2014 Japanese Society of Neuropathology.


Deng Z.,Huazhong University of Science and Technology | Mo X.,Huazhong University of Science and Technology | Liu S.,Wuhan University
International Journal of Medical Informatics | Year: 2014

Objective: Given the increasing number of older people, China has become an aging society. A mobile health service is a type of health informatics that provides personalized healthcare advice to those who require it, especially the older people and the middle-aged. However, few studies consider the adoption of mobile health services with regard to older and middle-aged users. This paper explored a research model based on the value attitude behavior model, theory of planned behavior, and four aging characteristic constructs to investigate how older and middle-aged citizens adopted mobile health services. Method: The hypothesized model was empirically tested using data collected from a survey of 424 residents older than 40 years in China. Structural equation modeling was used to estimate the significance of the path coefficients. Results: The findings revealed that (1) perceived value, attitude, perceived behavior control, and resistance to change can be used to predict intention to use mobile health services for the middle-aged group; (2) perceived value, attitude, perceived behavior control, technology anxiety, and self-actualization need positively affected the behavior intention of older users; and (3) subjective norm and perceived physical condition showed no significant effects on the behavior intention to use mobile health services for the two groups. The theoretical and practical implications and contributions of this study are then discussed. © 2014 Elsevier Ireland Ltd.


Chen S.,Huazhong University of Science and Technology | Tian Z.,Wuhan University
International Journal of Heat and Fluid Flow | Year: 2010

We discuss the implementation of the recently developed Langmuir slip model, which possesses a clearer physical picture than the popularly used Maxwell slip model, for the lattice Boltzmann (LB) method to capture velocity slip and temperature jump in microfluidics. The implementation of this scheme is straightforward even when boundary walls do not run coincidentally along the lattice grids. Some previous LB boundary schemes for macroscopic thermal flows can be naturally recovered from the present scheme when the Knudsen number Kn → 0. The feasibility and the capability of the present scheme for thermal micro-flow simulations are explored by numerical experiments. © 2009 Elsevier Inc. All rights reserved.


Yin D.,Huazhong University of Science and Technology | Yin D.,University College London | Kulhalli V.,University of London | Walker A.P.,University College London
Hepatology | Year: 2014

Hyperferritinemia and bilateral cataracts are features of the rare hereditary hyperferritinemia cataract syndrome (HHCS; OMIM #600886). HHCS is an autosomal dominant condition caused by mutations which increase expression of the ferritin light polypeptide (FTL) gene. We report a patient with HHCS who was misdiagnosed and treated as having hemochromatosis, in whom a heterozygous c.-160A>G mutation was identified in the iron responsive element (IRE) of FTL, causing ferritin synthesis in the absence of iron overload. This report demonstrates the need for clinical awareness of HHCS as a cause of hyperferritinemia in the absence of iron overload and provides a possible diagnostic schema. (Hepatology 2014;59:1204-1206) © 2014 The Authors. HEPATOLOGY published by Wiley on behalf of the American Association for the Study of Liver Diseases.


Tang Y.,University of Rhode Island | He H.,University of Rhode Island | Wen J.,Huazhong University of Science and Technology | Liu J.,Huazhong University of Science and Technology
IEEE Transactions on Smart Grid | Year: 2015

In this paper, a goal representation heuristic dynamic programming (GrHDP) based controller is developed for the doubly-fed induction generator based wind farm to improve the system transient stability under fault conditions. The proposed controller is based on adaptive dynamic programming (ADP) techniques to approximate the optimal control policy according to the interaction between the controller and the power plant. Compared to existing ADP approaches with one action network and one critic network, our GrHDP architecture introduces an additional network, i.e., the reference network, to form an internal goal/reward representation. This better mapping between the system state and the control action significantly improves the control performance. The effectiveness of the proposed approach is validated via two cases. The first case investigates a revised four-machine two-area system with high wind penetration and a static synchronous compensator. The second case is a practical size power system with wind farm in Liaoning Province in China. Detailed simulation analysis and comparative studies with traditional ADP approaches are presented to demonstrate the superior performance of our method. © 2014 IEEE.


Liu J.,Wuhan University | Shao Z.,Wuhan University | Cheng Q.,Huazhong University of Science and Technology
Optics Letters | Year: 2011

In this Letter, the color constancy and its realization were studied and a novel color constancy image enhancement algorithm under poor illumination was presented. The purpose of this algorithm is to maintain the hue of an image during the processing so that the change of saturation can be minimized. The original image was first multiplied by a scale parameter obtained by the adaptive quadratic function to enhance the luminance, and then the edge details were restored by a shifting parameter. Numerical results of the Simon Fraser University (SFU) image database indicated that the proposed algorithm performed much better in preserving the hue and saturation and avoiding color distortion compared with the existing image enhancement algorithms. © 2011 Optical Society of America.


Cai J.,Hubei University | Cai J.,Huazhong University of Science and Technology | Yu B.,Huazhong University of Science and Technology
Transport in Porous Media | Year: 2011

In the past decades, there was considerable controversy over the Lucas-Washburn (LW) equation widely applied in capillary imbibition kinetics. Many experimental results showed that the time exponent of the LW equation is less than 0. 5. Based on the tortuous capillary model and fractal geometry, the effect of tortuosity on the capillary imbibition in wetting porous media is discussed in this article. The average height growth of wetting liquid in porous media driven by capillary force following the L̄s(t)~ t1/2d T law is obtained (here DT is the fractal dimension for tortuosity, which represents the heterogeneity of flow in porous media). The LW law turns out to be the special case when the straight capillary tube (DT = 1) is assumed. The predictions by the present model for the time exponent for capillary imbibition in porous media are compared with available experimental data, and the present model can reproduce approximately the global trend of variation of the time exponent with porosity changing. © 2011 Springer Science+Business Media B.V.


Panigrahy D.,Dana-Farber Cancer Institute | Greene E.R.,Dana-Farber Cancer Institute | Pozzi A.,Vanderbilt University | Wang D.W.,Huazhong University of Science and Technology | Zeldin D.C.,National Health Research Institute
Cancer and Metastasis Reviews | Year: 2011

Inflammation and angiogenesis in the tumor microenvironment are increasingly implicated in tumorigenesis. Endogenously produced lipid autacoids, locally acting small-molecule mediators, play a central role in inflammation and tissue homeostasis. These lipid mediators, collectively referred to as eicosanoids, have recently been implicated in cancer. Although eicosanoids, including prostaglandins and leukotrienes, are best known as products of arachidonic acid metabolism by cyclooxygenases and lipoxygenases, arachidonic acid is also a substrate for another enzymatic pathway, the cytochrome P450 (CYP) system. This eicosanoid pathway consists of two main branches: ω-hydroxylases which converts arachidonic acid to hydroxyeicosatetraenoic acids (HETEs) and epoxygenases which converts it to four regioisomeric epoxyeicosatrienoic acids (EETs; 5,6-EET, 8,9-EET, 11,12-EET, and 14,15-EET). EETs regulate inflammation and vascular tone. The bioactive EETs are produced predominantly in the endothelium and are mainly metabolized by soluble epoxide hydrolase to less active dihydroxyeicosatrienoic acids. EET signaling was originally studied in conjunction with inflammatory and cardiovascular disease. Arachidonic acid and its metabolites have recently stimulated great interest in cancer biology. To date, most research on eicosanoids in cancer has focused on the COX and LOX pathways. In contrast, the role of cytochrome P450-derived eicosanoids, such as EETs and HETEs, in cancer has received little attention. While CYP epoxygenases are expressed in human cancers and promote human cancer metastasis, the role of EETs (the direct products of CYP epoxygenases) in cancer remains poorly characterized. In this review, the emerging role of EET signaling in angiogenesis, inflammation, and cancer is discussed. © 2011 Springer Science+Business Media, LLC (outside the USA).


The team's findings, which were recently published in the journal Nature Communications, show that using salt crystals as a template to grow thin sheets of conductive metal oxides make the materials turn out larger and more chemically pure—which makes them better suited for gathering ions and storing energy. "The challenge of producing a metal oxide that reaches theoretical performance values is that the methods for making it inherently limit its size and often foul its chemical purity, which makes it fall short of predicted energy storage performance," said Jun Zhou, a professor at HUST's Wuhan National Laboratory for Optoelectronics and an author of the research. Our research reveals a way to grow stable oxide sheets with less fouling that are on the order of several hundreds of times larger than the ones that are currently being fabricated." In an energy storage device—a battery or a capacitor, for example—energy is contained in the chemical transfer of ions from an electrolyte solution to thin layers of conductive materials. As these devices evolve they're becoming smaller and capable of holding an electric charge for longer periods of time without needing a recharge. The reason for their improvement is that researchers are fabricating materials that are better equipped, structurally and chemically, for collecting and disbursing ions. In theory, the best materials for the job should be thin sheets of metal oxides, because their chemical structure and high surface area makes it easy for ions to attach—which is how energy storage occurs. But the metal oxide sheets that have been fabricated in labs thus far have fallen well short of their theoretical capabilities. According to Zhou, Tang and the team from HUST, the problem lies in the process of making the nanosheets—which involves either a deposition from gas or a chemical etching—often leaves trace chemical residues that contaminate the material and prevent ions from bonding to it. In addition, the materials made in this way are often just a few square micrometers in size. Using salt crystals as a substrate for growing the crystals lets them spread out and form a larger sheet of oxide material. Think of it like making a waffle by dripping batter into a pan versus pouring it into a big waffle iron; the key to getting a big, sturdy product is getting the solution—be it batter, or chemical compound—to spread evenly over the template and stabilize in a uniform way. "This method of synthesis, called 'templating'—where we use a sacrificial material as a substrate for growing a crystal—is used to create a certain shape or structure," said Yury Gogotsi, PhD, University and Trustee Chair professor in Drexel's College of Engineering and head of the A.J. Drexel Nanomaterials Institute, who was an author of the paper. "The trick in this work is that the crystal structure of salt must match the crystal structure of the oxide, otherwise it will form an amorphous film of oxide rather than a thing, strong and stable nanocrystal. This is the key finding of our research—it means that different salts must be used to produce different oxides." Researchers have used a variety of chemicals, compounds, polymers and objects as growth templates for nanomaterials. But this discovery shows the importance of matching a template to the structure of the material being grown. Salt crystals turn out to be the perfect substrate for growing oxide sheets of magnesium, molybdenum and tungsten. The precursor solution coats the sides of the salt crystals as the oxides begin to form. After they've solidified, the salt is dissolved in a wash, leaving nanometer-thin two-dimensional sheets that formed on the sides of the salt crystal—and little trace of any contaminants that might hinder their energy storage performance. By making oxide nanosheets in this way, the only factors that limit their growth is the size of the salt crystal and the amount of precursor solution used. "Lateral growth of the 2D oxides was guided by salt crystal geometry and promoted by lattice matching and the thickness was restrained by the raw material supply. The dimensions of the salt crystals are tens of micrometers and guide the growth of the 2D oxide to a similar size," the researchers write in the paper. "On the basis of the naturally non-layered crystal structures of these oxides, the suitability of salt-assisted templating as a general method for synthesis of 2D oxides has been convincingly demonstrated." As predicted, the larger size of the oxide sheets also equated to a greater ability to collect and disburse ions from an electrolyte solution—the ultimate test for its potential to be used in energy storage devices. Results reported in the paper suggest that use of these materials may help in creating an aluminum-ion battery that could store more charge than the best lithium-ion batteries found in laptops and mobile devices today. Gogotsi, along with his students in the Department of Materials Science and Engineering, has been collaborating with Huazhong University of Science and Technology since 2012 to explore a wide variety of materials for energy storage application. The lead author of the Nature Communications article, Xu Xiao, and co-author Tiangi Li, both Zhou's doctoral students, came to Drexel as exchange students to learn about the University's supercapacitor research. Those visits started a collaboration, which was supported by Gogotsi's annual trips to HUST. While the partnership has already yielded five joint publications, Gogotsi speculates that this work is only beginning. "The most significant result of this work thus far is that we've demonstrated the ability to generate high-quality 2D oxides with various compositions," Gogotsi said. "I can certainly see expanding this approach to other oxides that may offer attractive properties for electrical energy storage, water desalination membranes, photocatalysis and other applications." Explore further: New nanosheet growth technique has potential to revolutionize nanotechnology industry


Lu X.-Y.,Huazhong University of Science and Technology | Jing H.,Henan Normal University | Ma J.-Y.,Huazhong University of Science and Technology | Wu Y.,Huazhong University of Science and Technology
Physical Review Letters | Year: 2015

We demonstrate PT-symmetry-breaking chaos in an optomechanical system, which features an ultralow driving threshold. In principle, this chaos will emerge once a driving laser is applied to the cavity mode and lasts for a period of time. The driving strength is inversely proportional to the starting time of chaos. This originally comes from the dynamical enhancement of nonlinearity by field localization in the PT-symmetry-breaking phase. Moreover, this chaos is switchable by tuning the system parameters so that a PT-symmetry phase transition occurs. This work may fundamentally broaden the regimes of cavity optomechanics and nonlinear optics. It offers the prospect of exploring ultralow-power-laser-triggered chaos and its potential applications in secret communication. © 2015 American Physical Society.


Tsai C.-W.,Chia Nan University of Pharmacy and Science | Lai C.-F.,National Chung Cheng University | Chiang M.-C.,National Sun Yat - sen University | Yang L.T.,Huazhong University of Science and Technology | Yang L.T.,St. Francis Xavier University
IEEE Communications Surveys and Tutorials | Year: 2014

It sounds like mission impossible to connect everything on the earth together via internet, but Internet of Things (IoT) will dramatically change our life in the foreseeable future, by making many «impossibles» possible. To many, the massive data generated or captured by IoT are considered having highly useful and valuable information. Data mining will no doubt play a critical role in making this kind of system smart enough to provide more convenient services and environments. This paper begins with a discussion of the IoT. Then, a brief review of the features of «data from IoT» and «data mining for IoT' is given». Finally, changes, potentials, open issues, and future trends of this field are addressed. © 2014 IEEE.


Wang L.,Huazhong University of Science and Technology | Wang L.,Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2011

In this paper, a new, modified nonlocal beam model is developed for analyzing the vibration and stability of nanotubes conveying fluid, in which one single nonlocal nanoscale parameter is included. Using Hamilton's principle, a new higher-order differential equation of motion and the corresponding higher-order, non-classical boundary conditions are obtained for nanotubes conveying fluid. Based on this modified nonlocal model, effect of nonlocal nanoscale parameter on natural frequencies and critical flow velocities is presented and discussed through numerical calculations. It is found that this factor has great influence on the vibration and stability of nanotubes conveying fluid. In particular, the nonlocal effect tends to induce higher natural frequencies and higher critical flow velocities as compared to the results obtained from the classical and partial nonlocal beam models. © 2011 Elsevier B.V. All rights reserved.


Lu D.,Huazhong University of Science and Technology | Gong Y.,Huazhong University of Science and Technology | Wang W.,Luoyang Normal University
Advanced Synthesis and Catalysis | Year: 2010

Several novel prolylprolinol catalysts have been designed and synthesized. This type of compound showed high catalytic efficiency on pro-moting the direct addition of unmodified aldehydes to nitroalkenes. Among the catalysts surveyed, the least bulky member (8d) exhibited the best perfor-mance on both efficiency and stereoselectivity, pro-viding the products with up to 97% ee value with 1.5-5 mol% catalyst loading. Additionally, compu-tational studies of the transition state have been conducted to explain the high diastereo- and enan-tioselectivity. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.


Wu X.,University of Hong Kong | Liu S.,Huazhong University of Science and Technology | Li J.,University of Hong Kong | Lam E.Y.,University of Hong Kong
Optics Express | Year: 2014

In 22nm optical lithography and beyond, source mask optimization (SMO) becomes vital for the continuation of advanced ArF technology node development. The pixel-based method permits a large solution space, but involves a time-consuming optimization procedure because of the large number of pixel variables. In this paper, we introduce the Zernike polynomials as basis functions to represent the source patterns, and propose an improved SMO algorithm with this representation. The source patterns are decomposed into the weighted superposition of some well-chosen Zernike polynomial functions, and the number of variables decreases significantly. We compare the computation efficiency and optimization performance between the proposed method and the conventional pixel-based algorithm. Simulation results demonstrate that the former can obtain substantial speedup of source optimization while improving the pattern fidelity at the same time. © 2014 Optical Society of America.


Zhang X.,Huazhong University of Science and Technology | Huang G.Q.,University of Hong Kong
International Journal of Production Economics | Year: 2010

This paper deals with simultaneous configuration of platform products and supply chains. The supply chain consists of one manufacturer and multiple cooperative suppliers. A common platform is shared for developing/configuring the product family with variant modules which are substitutable in the sense that high-performance module options can replace low-performance ones. As the customer in the supply chain, the manufacturer takes its leading role by making the first move to produce decisions on platform products configuration (PPC) and supplier selection. The manufacturer and concerned suppliers then move cooperatively to make their ordering and pricing decisions with a common objective to maximize their joint payoffs. We derive the optimal solution ranges for this two-moves dynamic game according to Nash's bargaining model. An iterative algorithm is developed to find the subgame perfect equilibrium. A numerical study is conducted through a series of simulation experiments to illustrate how useful insights about the mutual impacts between the PPC and SCC (supply chain configuration) decisions can be obtained from the proposed game models and solution procedure. The results are further compared with those obtained in a previous study with non-cooperative suppliers. The comparative study allows us to appreciate managerial measures under different supply chain coordination schemes. It is found that a supply chain with cooperative suppliers is more effective by using the lot-for-lot policy and more competitive by accommodating higher product variety. © 2009 Elsevier B.V. All rights reserved.


Wang L.,Huazhong University of Science and Technology | Wang L.,Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment
Acta Mechanica Solida Sinica | Year: 2012

In the past decades, it has been reported that divergence is the expected form of instability for fluid-conveying pipes with both ends supported. In this paper, the form of instability of supported pipes conveying fluid subjected to distributed follower forces is investigated. Based on the Pflüger column model, the equation of motion for supported pipes subjected concurrently to internal fluid flow and distributed follower forces is established. The analytical model, after Galerkin discretization to two degrees of freedom, is evaluated by analyzing the corresponding eigenvalue problem. The complex frequencies versus fluid velocity are obtained for various system parameters. The results show that either buckling or flutter instabilities could occur in supported fluid-conveying pipes under the action of distributed follower forces, depending on the parameter values of distributed follower forces. © 2012 The Chinese Society of Theoretical and Applied Mechanics.


Zhou X.,Huazhong University of Science and Technology | Zhou X.,Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment
Acta Mechanica Solida Sinica | Year: 2012

Based on the Flügge shell theory, equations of motion of ring-stiffened thin-walled cylindrical shells conveying fluid are developed with the aid of the Hamilton's principle. Analysis is carried out on the vibration and stability of the ring-stiffened shells conveying fluid, and the effects of fluid velocity, the Young modulus, the size, and the number of the ring stiffeners on the natural frequency and the instability characteristics are examined. It is found that stiffeners can reduce the number of circumferential waves for the fundamental mode, and increase the shell's natural frequency, and thus the critical fluid velocity. For the number of longitudinal half waves being equal to one, the natural frequency and the corresponding critical fluid velocity are the largest for the internal-ring stiffened shell and are the smallest for the symmetrical-ring stiffened shell. The natural frequencies and the corresponding critical fluid velocity predicted by the established model increase with the increase in the Young modulus, the size, or the number of the stiffeners. © 2012 The Chinese Society of Theoretical and Applied Mechanics.


Li M.,Huazhong University of Science and Technology | Gu Y.,Huazhong University of Science and Technology | Gu Y.,CAS Lanzhou Institute of Chemical Physics
Advanced Synthesis and Catalysis | Year: 2012

The selectivity of a three-component electrophilic reaction of an aldehyde with dimedone and another carbon-based nucleophile could be improved by a reversible alkylation procedure, which involves formation, breaking and regeneration of C-C bonds. In the presence of iron(III) chloride and triphenylphosphine, an analogous C-C bond breaking can be observed in the reaction of 2,3,4,9-tetrahydro-9-(2-hydroxy-4,4-dimethyl-6-oxo-1-cyclohexen-1- yl)-3,3-dimethyl-1H-xanthen-1-one, in which the fragment of dimedone was replaced by a carbon-based nucleophile. Inspired by this observation, some three-component reactions of salicyldehyde and dimedone were successfully developed by using iron(III) chloride and triphenylphosphine (PPh 3) as catalyst. PPh 3 plays the role of hydrogen bond acceptor, which confers a good flexibility of the substrate by weakening the intramolecular hydrogen bond, allowing thus an easy interaction of the substrate with iron(III) chloride catalyst. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Gu Y.,Huazhong University of Science and Technology | Gu Y.,CAS Lanzhou Institute of Chemical Physics
Green Chemistry | Year: 2012

Simple and green synthetic procedures constitute an important goal in organic synthesis. The combination of multicomponent reactions (MCRs) and unconventional solvents has become a new research direction, which enables simultaneous growth of both MCRs and green solvents toward ideal organic synthesis. This review summarizes recent results of MCRs obtained in unconventional media including water, ionic liquids, polyethylene glycol and bio-based solvents. © 2012 The Royal Society of Chemistry.


Suk J.,University of Texas at Austin | Wu Z.,Huazhong University of Science and Technology | Wang L.,Huazhong University of Science and Technology | Bard A.J.,University of Texas at Austin
Journal of the American Chemical Society | Year: 2011

We report the electrochemical characterization and the observation of excimer emission from a series of 9-naphthylanthracene-based dimer- and trimer-bridged high steric hindrance aromatic groups during photoluminescence (PL) measurements in the solid state and in solution electrogenerated chemiluminescence (ECL) measurements. Cyclic voltammetry of 4,4′-bis(9-(1- naphthyl)anthracen-10-yl)biphenyl (4A) and 1,3,5-tris(9-(1-naphthyl)anthracen- 10-yl)benzene (4C) showed two or three reversible, closely spaced one-electron transfers on oxidation in dichloromethane. The ECL emission spectra of 4A and 4C resulting from the annihilation reaction in benzonitrile showed two bands: one at the same wavelength as the PL peak in the solution state, and a broad band at longer wavelength. With a coreactant, such as peroxydisulfate, ECL spectra showed a single peak that was less broad in shape. PL measurement in the solid state and measurement of representative time traces of PL intensity, lifetimes, and picosecond time-correlated single-photon counting confirmed excimer emission at long wavelength. A reprecipitation method was used to prepare well-dispersed organic nanoparticles (NPs) of 4A in both aqueous and acetonitrile solutions. The smallest stable size of NPs produced was ∼15 ± 6 nm, as analyzed by transmission electron microscopy. These organic NPs produced stable and weak ECL emission from the annihilation reaction in both aqueous and MeCN solutions. With a coreactant, such as peroxydisulfate, the ECL signal on reduction was sufficiently strong to obtain an ECL spectrum. © 2011 American Chemical Society.


Li J.,University of Hong Kong | Liu S.,Huazhong University of Science and Technology | Lam E.Y.,University of Hong Kong
Optics Express | Year: 2013

Source mask optimization (SMO) is a powerful and effective technique to obtain sufficient process stability in optical lithography, particularly in view of the challenges associated with 22nm process technology and beyond. However, SMO algorithms generally involve computationintensive nonlinear optimization. In this work, a fast algorithm based on augmented Lagrangian methods (ALMs) is developed for solving SMO. We first convert the optimization to an equivalent problem with constraints using variable splitting, and then apply an alternating minimization method which gives a straightforward implementation of the algorithm. We also use the quasi-Newton method to tackle the sub-problem so as to accelerate convergence, and a tentative penalty parameter schedule for adjustment and control. Simulation results demonstrate that the proposed method leads to faster convergence and better pattern fidelity. © 2013 Optical Society of America.


Zhang X.,Beijing Institute of Technology | Chen R.,Huazhong University of Science and Technology
International Journal of Production Economics | Year: 2013

Asymmetric effects and regulatory focus are two fundamental rules behind an individual's judgment and motivation. While recent research on loss aversion presents mixed evidence, the literature on satisfaction studies provides little insight into the influence of regulatory systems on satisfaction. Moreover, literature regarding the potential interactions between asymmetric effects and regulatory focus is missing. In this paper, we examined the inconsistent evidence regarding loss aversion and various asymmetric effects in different types of regulatory focus at the attribute level. We conducted an experimental study in a setting of airline overbooking recovery in the Chinese airline industry. Our evidence shows that regulatory focus influences asymmetric effects. Participants with different types of regulatory focus have different priorities in recovery attributes and exhibit quite different patterns of asymmetric effects. We identify four different asymmetric effects and find one failure to present - an effect in our study. In addition, we present a regulatory focus-based dummy regression model, which is a more general method that nests previous research on attribute-satisfaction as a special case. The results, together with the newly proposed passenger classification (time fixed versus time flexible), underpin a more realistic assumption for future theory building and can thus help airline companies design a better recovery strategy for revenue management. © 2012 Elsevier B.V. All rights reserved.


Wei T.,Huazhong University of Science and Technology | Zhang Q.,Huazhong University of Science and Technology | Huang Y.-H.,Huazhong University of Science and Technology | Goodenough J.B.,University of Texas at Austin
Journal of Materials Chemistry | Year: 2012

The fabrication of a solid oxide fuel cell (SOFC) with symmetrical anode/cathode electrodes is a practical strategy to reduce strain, promote co-sintering of the electrodes, and hence to improve stability and reliability. Non-stoichiometric Sr2Co1+xMo1-xO6 (x = 0.1, 0.15, 0.2) (SCMO) double perovskites are designed to be used as symmetrical anode/cathode electrodes for symmetrical SOFCs with La 0.8Sr0.2Ga0.83Mg0.17O3 (LSGM) as electrolyte. As an individual anode or cathode, SCMO shows considerable electrochemical performance. A typical cell with Sr 2Co1.15Mo0.85O6 as the symmetrical anode/cathode electrodes, the maximum power density reaches as high as 460 mW cm-2 at 800 °C. The thermal expansion coefficient (TEC) of SCMO ranges from 6 × 10-6 to 15 × 10-6 K -1 from room temperature to 900 °C, matching well that of the conventional LSGM electrolyte.


Chen M.Z.Q.,University of Hong Kong | Zhang L.,University of Hong Kong | Su H.,Huazhong University of Science and Technology | Li C.,Chinese Academy of Sciences
IET Control Theory and Applications | Year: 2015

This study investigates the problem of event-based synchronisation of linear discrete-time dynamical networks. Leader-following and leaderless synchronisations are achieved by a distributed event-trigger strategy. It is shown that feedback control updating is unnecessary until an event is triggered. The combinational-state variables and the Riccati equation are used to construct a Liapunov function and to design the event-triggering conditions. Numerical examples are provided to illustrate the theoretical results. © The Institution of Engineering and Technology 2015.


Han J.-T.,University of Texas at Austin | Han J.-T.,Los Alamos National Laboratory | Huang Y.-H.,Huazhong University of Science and Technology | Goodenough J.B.,University of Texas at Austin
Chemistry of Materials | Year: 2011

A new anode material TiNb2O7 was synthesized by a sol-gel method. TiNb2O7 and its derivates display exciting performances at 1.3-1.6 V versus Li+/Li0, which is fully reversible and capable of fast charge and discharge rates. © 2011 American Chemical Society.


Wang L.,Huazhong University of Science and Technology | Wang L.,Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment
Computational Materials Science | Year: 2010

This paper initiates a theoretical analysis of wave propagation of fluid-conveying single-walled carbon nanotubes based on strain gradient elasticity theory with consideration of both inertia and strain gradients, in which two small-scale parameters are accounted for. For comparison purpose, the stress gradient theory for fluid-conveying carbon nanotubes is also discussed. Both theories are formulated using either the Euler-Bernoulli or the Timoshenko beam assumptions. It is found that the results predicted by these beam models are quite different. From a continuum-based point-of-view, the combined strain/inertia gradient Timoshenko beam model and its conclusion regarding wave propagation may be more reliable. Results show that the effect of internal fluid flow on the phase velocity of upstream-travelling wave is significant when the wave number is relatively low. However, this effect may be ignored when the wave number is sufficiently high. Moreover, the two small-scale parameters related to the inertia and strain gradients are shown to significantly affect the phase velocity at higher wave numbers. The present theoretical study highlights the significance of the effects of fluid flow and small scale related to inertia gradients on wave propagation in carbon nanotubes conveying fluid. © 2010 Elsevier B.V. All rights reserved.


Wang L.,Huazhong University of Science and Technology | Wang L.,Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2010

An analytical model for predicting surface effects on the free vibration of fluid-conveying nanotubes is developed based on the non-local elasticity theory. In the new model, the effects of both inner and outer surface layers on the nanotubes are taken into consideration. The results show that the surface effects with positive elastic constant or positive residual surface tension tend to increase the natural frequency and critical flow velocity. For small tube thickness or large aspect ratio, the stability of the nanotubes will be greatly enhanced due to the surface effect. This study may be useful to accurately measure the vibration characteristics of fluid-conveying nanotubes and to design nanofluidic devices. © 2010 Elsevier B.V.


Gu Y.,Huazhong University of Science and Technology | Gu Y.,CAS Lanzhou Institute of Chemical Physics | Jerome F.,CNRS Poitiers Institute of Chemistry: Materials and Natural Resources
Chemical Society Reviews | Year: 2013

Biomass and waste exhibit great potential for replacing fossil resources in the production of chemicals. The search for alternative reaction media to replace petroleum-based solvents commonly used in chemical processes is an important objective of significant environmental consequence. Recently, bio-based derivatives have been either used entirely as green solvents or utilized as pivotal ingredients for the production of innovative solvents potentially less toxic and more bio-compatible. This review presents the background and classification of these new media and highlights recent advances in their use in various areas including organic synthesis, catalysis, biotransformation and separation. The greenness, advantages and limitations of these solvents are also discussed. © 2013 The Royal Society of Chemistry.


Jiang T.,Huazhong University of Science and Technology | Li X.,Beijing Institute of Technology
IEEE Transactions on Vehicular Technology | Year: 2010

In this paper, we apply fountain codes to control the peak-to-average power ratio (PAPR) of orthogonal frequency-division multiplexing (OFDM) signals. The main key idea of the proposed scheme is based on the fact that the best fountain-coded OFDM packets can be generated with a low PAPR. Both theoretical analysis and simulation results prove that the proposed scheme can effectively obtain the desirable PAPR and good throughput with rateless codes. Moreover, the flexibility of controlling PAPR makes the proposed scheme more suitable for implementing random frame sizes and providing effective error detection. © 2006 IEEE.


Sun S.,Huazhong University of Science and Technology | Bai R.,Huazhong University of Science and Technology | Gu Y.,Huazhong University of Science and Technology | Gu Y.,CAS Lanzhou Institute of Chemical Physics
Chemistry - A European Journal | Year: 2014

Lignosulfonate (LS) is an organic waste generated as a byproduct of the cooking process in sulfite pulping in the manufacture of paper. In this paper, LS was used as an anionic supporting material for immobilizing cationic species, which can then be used as heterogeneous catalysts in some organic transformations. With this strategy, three lignin-supported catalysts were prepared including 1) lignin- SO3Sc(OTf)2, 2) lignin-SO3Cu(OTf), and 3) lignin-IL@NH2 (IL= ionic liquid). These solid materials were then examined in many organic transformations. It was finally found that, compared with its homogeneous counterpart as well as some other solid catalysts that are prepared by using different supports with the same metal or catalytically active species, the lignin-supported catalysts showed better performance in these reactions not only in terms of activity but also with regard to recyclability. © 2014 Wiley-VCH Verlag GmbH& Co. KGaA, Weinheim.


Lu Y.,Huazhong University of Science and Technology | Yang S.,Huazhong University of Science and Technology | Chau P.Y.K.,University of Hong Kong | Cao Y.,Huazhong University of Science and Technology
Information and Management | Year: 2011

Many Internet-based services have already been ported to the mobile-based environment, embracing the new services is therefore critical to deriving revenue for services providers. Based on a valence framework and trust transfer theory, we developed a trust-based customer decision-making model of the non-independent, third-party mobile payment services context. We empirically investigated whether a customer's established trust in Internet payment services is likely to influence his or her initial trust in mobile payment services. We also examined how these trust beliefs might interact with both positive and negative valence factors and affect a customer's adoption of mobile payment services. Our SEM analysis indicated that trust indeed had a substantial impact on the cross-environment relationship and, further, that trust in combination with the positive and negative valence determinants directly and indirectly influenced behavioral intention. In addition, the magnitudes of these effects on workers and students were significantly different from each other. © 2011 Elsevier B.V.


Li M.,Huazhong University of Science and Technology | Zhang B.,Huazhong University of Science and Technology | Gu Y.,Huazhong University of Science and Technology | Gu Y.,CAS Lanzhou Institute of Chemical Physics
Green Chemistry | Year: 2012

Three-component reactions of salicylaldehydes, 1,3-cyclohexanediones and a sulfur, carbon, or nitrogen-based nucleophile were developed, for the first time, by using l-proline as a catalyst, which generated various substituted 4H-chromene derivatives in good to excellent yields. The reactions were performed in ethanol under mild and metal-free conditions. In these reactions, the use of l-proline as a catalyst was proven to be key for rendering the reactions possible because replacing l-proline with other acids or bases resulted in the generation of many side products. Many nucleophiles, such as thiophenols, mercaptans, indoles, sulfinic acid, benzotriazole, 2-naphthol, 5-methyl-2-phenyl-1,2-dihydropyrazol-3-one, 6-aminouracil, 6-amino-1,3-dimethyl- 1,2,3,4-tetrahydropyrimidine-2,4-dione and some commonly used C-H acids including 4-hydroxycoumarin, 2-hydroxy-1,4-naphthoquinone and barbituric acid could be successively used to assemble with dimedone and salicylaldehyde. Particularly, the product generated from the reaction of benzotriazole, 3-methoxysalicylaldehyde and dimedone can also be used as a starting material, in which the fragment of benzotriazole acts as a leaving group, for the synthesis of some important compounds by reacting with many carbon-based nucleophiles, such as dibenzoylmethane, ethyl benzoylacetate, 1,3-cyclohexanedione, N,N-dimethylaniline, 2-methylfuran and sesamol in acidic conditions. This offers a complementary route to access some 4H-chromenes that cannot be attained with the above-mentioned three-component reactions. © 2012 The Royal Society of Chemistry.


Hu S.,Huazhong University of Science and Technology | Yue D.,Huazhong University of Science and Technology | Liu J.,Nanjing University of Finance and Economics
Information Sciences | Year: 2012

This paper studies the H∞ filtering problem for a class of discrete-time networked systems with partly known distribution transmission delays. It is assumed that the random sensor-filter delay satisfies Markovian characteristics, but the transition probabilities of the delay transferring from one value to others are partly known. A novel measurement model is proposed to reflect the random delay of the transmission modes and the resulting filtering error system is modeled as a Markovian jump system (MJS) with multiple modes and state delay. Sufficient conditions are derived for the filtering error system to be stochastically stable and ensure a prescribed H∞ disturbance attenuation level bound by using mode-dependent Lyapunov functional approach. Based on the derived conditions, a design procedure for the H∞ filter is also presented. A numerical example is provided to show the design process of the filter and the effectiveness of the proposed method. © 2012 Elsevier Inc. All rights reserved.


Hu Y.,University of Hong Kong | Su H.,Huazhong University of Science and Technology | Lam J.,University of Hong Kong
International Journal of Robust and Nonlinear Control | Year: 2013

This paper is concerned with the second-order consensus problem of multi-agent systems with a virtual leader, where all agents and the virtual leader share the same intrinsic dynamics with a locally Lipschitz condition. It is assumed that only a small fraction of agents in the group are informed about the position and velocity of the virtual leader. A connectivity-preserving adaptive controller is proposed to ensure the consensus of multi-agent systems, wherein no information about the nonlinear dynamics is needed. Moreover, it is proved that the consensus can be reached globally with the proposed control strategy if the degree of the nonlinear dynamics is smaller than some analytical value. Numerical simulations are further provided to illustrate the theoretical results. Copyright © 2012 John Wiley & Sons, Ltd.


Takahashi E.J.,RIKEN | Lan P.,RIKEN | Lan P.,Huazhong University of Science and Technology | Mucke O.D.,German Electron Synchrotron | And 3 more authors.
Nature Communications | Year: 2013

High-energy isolated attosecond pulses required for the most intriguing nonlinear attosecond experiments as well as for attosecond-pump/attosecond-probe spectroscopy are still lacking at present. Here we propose and demonstrate a robust generation method of intense isolated attosecond pulses, which enable us to perform a nonlinear attosecond optics experiment. By combining a two-colour field synthesis and an energy-scaling method of high-order harmonic generation, the maximum pulse energy of the isolated attosecond pulse reaches as high as 1.3 mJ. The generated pulse with a duration of 500 as, as characterized by a nonlinear autocorrelation measurement, is the shortest and highest-energy pulse ever with the ability to induce nonlinear phenomena. The peak power of our tabletop light source reaches 2.6GW, which even surpasses that of an extreme-ultraviolet free-electron laser. © 2013 Macmillan Publishers Limited. All rights reserved.


Wang L.,Huazhong University of Science and Technology | Wang L.,Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment
Journal of Fluids and Structures | Year: 2010

In this paper, a new theoretical model is developed, based on the modified couple stress theory, for the vibration analysis of fluid-conveying microtubes by introducing one internal material length scale parameter. Using Hamilton's principle, the equations of motion of fluid-conveying microtubes are derived. After discretization via the Differential Quadrature Method (DQM), the analytical model exhibits some essential vibration characteristics. For a microtube in which both ends are supported, it is found that the natural frequencies decrease with increasing internal flow velocities. It is also shown that the microtube will become unstable by divergence at a critical flow velocity. More significantly, when the outside diameter of the microtube is comparable to the material length scale parameter, the natural frequencies obtained using the modified couple stress theory are much larger than those obtained using the classical beam theory. It is not surprising, therefore, that the critical flow velocities predicted by the modified couple stress theory are generally higher than those predicted by the classical beam theory. © 2010 Elsevier Ltd.


Yang S.,Zhejiang University of Finance and Economics | Lu Y.,Huazhong University of Science and Technology | Chau P.Y.K.,University of Hong Kong
Decision Support Systems | Year: 2013

As increasingly more organizations transit from a brick-and-mortar into a brick-and-click organization, consumers' embracing the new online channel is becoming critical to the success of these organizations. Although consumers' online channel adoption behavior has recently received a lot of attention, there still lacks a systematic investigation into the internal mechanism of consumers' channel adoption behaviors, especially, in an offline plus online channel context. Using brand extension theory and expectation-confirmation theory as the theoretical basis, this study examines what factors affect a consumer's decision on moving or extending from an offline channel to an online channel. A research model based on the above two theories is developed and empirically tested against data collected from 308 customers of a major commercial bank in China. The results confirm the usefulness of the two theories in explaining the online channel adoption and identify the concurrence effects of cross-channel synergies and dissynergies on customer's channels evaluation. This research advances our theoretical understanding of online channel adoption behaviors and offers practical implications for organizations to manage such online channel adoption. © 2012 Elsevier B.V.


Liu J.,Huazhong University of Science and Technology | Liu J.,University of Kentucky | Zhan C.-G.,University of Kentucky
Journal of Chemical Theory and Computation | Year: 2012

The reaction pathway of (-)-cocaine hydrolysis catalyzed by our recently discovered, most efficient cocaine hydrolase, which is the A199S/F227A/S287G/ A328W/Y332G mutant of human butyrylcholinesterase (BChE), and the corresponding free energy profile have been studied by performing first-principles pseudobond quantum mechanical/molecular mechanical (QM/MM)-free energy (FE) calculations. On the basis of the QM/MM-FE results, the catalytic hydrolysis process consists of four major reaction steps, including the nucleophilic attack on the carbonyl carbon of the (-)-cocaine benzoyl ester by the hydroxyl group of S198, dissociation of the (-)-cocaine benzoyl ester, nucleophilic attack on the carbonyl carbon of the (-)-cocaine benzoyl ester by water, and finally the dissociation between the (-)-cocaine benzoyl group and S198 of the enzyme. The second reaction step is rate-determining. The calculated free energy barrier associated with the transition state for the rate-determining step is ∼15.0 kcal/mol, which is in excellent agreement with the experimentally derived activation free energy of ∼14.7 kcal/mol. The mechanistic insights obtained from the present study will be valuable for the rational design of more active cocaine hydrolase against (-)-cocaine. In particular, future efforts aiming at further increasing the catalytic activity of the enzyme against (-)-cocaine should focus on stabilization of the transition state for the second reaction step in which the benzoyl ester of (-)-cocaine dissociates. © 2012 American Chemical Society.


Han W.,Huazhong University of Science and Technology | Zhang G.,CAS Lanzhou Institute of Chemical Physics | Li G.,Huazhong University of Science and Technology | Huang H.,CAS Lanzhou Institute of Chemical Physics
Organic Letters | Year: 2014

A rhodium-catalyzed sequential oxidative C-H annulation reaction between ketazines and internal alkynes has been developed via C-H and N-N bond activation with air as an external oxidant, which led to an efficient approach toward isoquinolines with high atom efficiency at rt. Utilizing the distinctive reactivity of this catalysis, both N-atoms of the azines could be efficiently incorporated to the desired isoquinolines under very robust and mild reaction conditions. © 2014 American Chemical Society.


Zhu S.,China University of Mining and Technology | Shen Y.,Huazhong University of Science and Technology
Neural Networks | Year: 2013

This paper analyzes the robustness of global exponential stability of stochastic recurrent neural networks (SRNNs) subject to parameter uncertainty in connection weight matrices. Given a globally exponentially stable stochastic recurrent neural network, the problem to be addressed here is how much parameter uncertainty in the connection weight matrices that the neural network can remain to be globally exponentially stable. We characterize the upper bounds of the parameter uncertainty for the recurrent neural network to sustain global exponential stability. A numerical example is provided to illustrate the theoretical result. © 2012 Elsevier Ltd.


Lei D.,University of Electronic Science and Technology of China | Li J.,Huazhong University of Science and Technology | Liu Z.,Huazhong University of Science and Technology
International Journal of Production Economics | Year: 2012

We study the risk management strategies in supplier chain when the disruptions of demand and cost are the private information. We use linear contract menus to analyze the supply chain under demand and cost disruptions with asymmetric information. We derive out the optimal contract for the supplier and show the impact of asymmetric disruption information on the performance of the supplier, the retailer and the supply chain. Further, we find out that the effects of demand and cost disruption may interact with each other while the production plan does not change in some cases. The optimal production quantity with asymmetric information is not greater than that with symmetric information. The information value for all members is not monotone in all parameters. Each change will induce that the supplier revises his strategy when the supply chain members trade off the cost of deviation and asymmetric information. © 2010 Elsevier B.V. All rights reserved.


Wang L.,Huazhong University of Science and Technology | Wang L.,Center for Fusion Theory | Diamond P.H.,Center for Fusion Theory | Diamond P.H.,University of California at San Diego
Physical Review Letters | Year: 2013

A mechanism for turbulent acceleration of parallel rotation is discovered using gyrokinetic theory. This new turbulent acceleration term cannot be written as a divergence of parallel Reynolds stress. Therefore, turbulent acceleration acts as a local source or sink of parallel rotation. The physics of turbulent acceleration is intrinsically different from the Reynolds stress. For symmetry breaking by positive intensity gradient, a positive turbulent acceleration, i.e., cocurrent rotation, is predicted. The turbulent acceleration is independent of mean rotation and mean rotation gradient, and so constitutes a new candidate for the origin of spontaneous rotation. A quasilinear estimate for ion temperature gradient turbulence shows that the turbulent acceleration of parallel rotation is explicitly linked to the ion temperature gradient scale length and temperature ratio Ti0/Te0. Methods for testing the effects of turbulent parallel acceleration by gyrokinetic simulation and experiment are proposed. © 2013 American Physical Society.


Liu W.-H.,Tianjin University | Xie D.,Tianjin University | Xu X.-C.,Huazhong University of Science and Technology
International Journal of Production Economics | Year: 2013

Quality supervision and coordination are critical in realising successful cooperation in the logistics service supply chain (LSSC). To build a closer partnership in the supply chain, collaboration in the LSSC presents multi-period features. Therefore, the study on the quality of decision-making problems under multi-period conditions in the LSSC is practical. Logistic service quality is not easy to measure. Hence, this paper proposes a multi-period quality coordination model based on the single-period quality coordination model in a two-echelon LSSC, and establishes a new model in a three-echelon LSSC when the logistics service integrator (LSI) is punished. Simulation results indicate that under multi-period cooperation conditions, the LSI tends to make rapid decisions when punishment intensity is below the critical value. Moreover, for the three-echelon LSSC, the final equilibrium between sub-LSI and ultimate FLSP is not associated with punishment intensity that the LSI sets against the sub-LSI. © 2012 Elsevier B.V.


Xie D.,Xiamen University of Technology | Zhang H.,Huazhong University of Science and Technology | Shu X.,Huazhong University of Science and Technology | Xiao J.,Huazhong University of Science and Technology
Optics Express | Year: 2012

The paper reports an effective method to fabricate micro-lens arrays with the ultraviolet-curable polymer, using an original pneumatically diaphragm-driven drop-on-demand inkjet system. An array of plano convex micro-lenses can be formed on the glass substrate due to surface tension and hydrophobic effect. The micro-lens arrays have uniform focusing function, smooth and real planar surface. The fabrication process showed good repeatability as well, fifty micro-lenses randomly selected form 9 × 9 mirolens array with an average diameter of 333.28μm showed 1.1% variations. Also, the focal length, the surface roughness and optical property of the fabricated micro-lenses are measured, analyzed and proved satisfactory. The technique shows great potential for fabricating polymer micro-lens arrays with high flexibility, simple technological process and low production cost. © 2012 Optical Society of America.


Ruan X.,Nanjing University of Aeronautics and Astronautics | Ruan X.,Huazhong University of Science and Technology | Tan S.-C.,Hong Kong Polytechnic University | Yang Y.,Nanjing University of Aeronautics and Astronautics | Ye Z.,Lite-On Technology
IEEE Transactions on Power Electronics | Year: 2012

The electrolytic capacitor is the key component that limits the operating lifetime of LED drivers. If an ac-dc LED driver with power factor correction (PFC) control is allowed to output a pulsating current for driving the LEDs, the electrolytic capacitor will no longer be required. However, this pulsating current will introduce light flicker that varies at twice the power line frequency. In this paper, a configuration of flicker-free electrolytic capacitor-less single-phase ac-dc driver for LED lighting is proposed. The configuration comprises an electrolytic capacitor-less PFC converter and a bidirectional converter, which serves to absorb the ac component of the pulsating current of the PFC converter, leaving only a dc component to drive the LEDs. The output filter capacitor of the bidirectional converter is intentionally designed to have a large voltage ripple, thus its capacitance can be greatly reduced. Consequently, film capacitors can be used instead of electrolytic capacitors, leading to the realization of a flicker-free ac-dc LED driver that has a long lifetime. The proposed solution is generally applicable to all single-phase PFC converters. A prototype with 48-V, 0.7-A output is constructed and tested. Experimental results are presented to verify the effectiveness of the flick-free electrolytic capacitor-less ac-dc LED driver. © 2012 IEEE.


Yao K.,Nanjing University of Aeronautics and Astronautics | Ruan X.,Huazhong University of Science and Technology | Mao X.,Nanjing University of Aeronautics and Astronautics | Ye Z.,Lite-On Technology
IEEE Transactions on Industrial Electronics | Year: 2011

A discontinuous-current-mode (DCM) boost power factor correction (PFC) converter features zero-current turn-on for the switch, no reverse recovery in diode, and constantfrequency operation. However, the input power factor (PF) is relatively low when the duty cycle is constant in a half line cycle. This paper derives the expressions of the input current and PF of the DCM boost PFC converter, and based on that, variable-duty-cycle control is proposed so as to improve the PF to nearly unity in the whole inputvoltage range. A method of fitting the duty cycle is further proposed for simplifying the circuit implementation. Other than a higher PF, the proposed variable-duty-cycle control achieves a lower outputvoltage ripple and a higher efficiency over constant-duty-cycle control. The experimental results from a 120-W universal input prototype are presented to verify the effectiveness of the proposed method. © 2010 IEEE.


Zhang X.,Tianjin University | De Pablos P.O.,University of Oviedo | Xu Q.,Huazhong University of Science and Technology
Computers in Human Behavior | Year: 2014

In multi-national and cross-cultural virtual classes, students' cultural values have significant impacts on knowledge sharing process. According to Hofstede's cultural dimensions, we conducted a mixed method to investigate how national cultural values effect on explicit and implicit knowledge sharing within a multi-national virtual class. First, we adopted a qualitative case study with 6 semi-structure interviews to explore the culture effects on knowledge sharing. Second, we conducted a cross-sectional survey to examine the interaction effects of culture and different knowledge sharing motivations. These findings suggest some cultural values (i.e.; collectivism) directly impact knowledge sharing, while most cultural values (i.e.; power distance, uncertainty avoidance, and Confucian dynamism) have interactive effects with knowledge sharing motivations. Furthermore, we also found some cultural values, like concern for face, have complex effects on knowledge sharing. This research contributes to the knowledge sharing literature, and provides practical implications for the organization work of computer-based education systems. © 2013 Elsevier Ltd. All rights reserved.


Zhu H.X.,University of Cardiff | Chen C.Y.,Huazhong University of Science and Technology
Mechanics of Materials | Year: 2011

This paper presents the combined effects of relative density and material distribution on the elastic constants and the yield strengths of metallic honeycombs. Periodic regular hexagonal cell is employed as the structural model. Cell wall bending, transverse shear and axial stretching/compression are taken as the deformation mechanisms in the analysis. Closed-form solutions for the yield strengths and all the five independent elastic constants are obtained for honeycombs with cell walls of uniform thickness. For honeycombs with cell walls of non-uniform thickness, the closed-form solutions would be too lengthy to use in practical applications. We instead provide numerical results to show the combined effects of relative density and material distribution on the initial and full yield strengths and all the five independent elastic constants of metallic honeycombs. The results can serve as a guide for the optimal design of metallic honeycombs. Crown Copyright © 2011 Published by Elsevier Ltd. All rights reserved.


Fu Z.,Shanghai Institute of Technology | Mo J.,Huazhong University of Science and Technology
International Journal of Advanced Manufacturing Technology | Year: 2011

Based on orthogonal test for air bending of high-strength steel sheets, 125 values of sheet thickness (t), tool gap (c), punch radius (r), ratio of yield strength to Young's modulus (σ y /E), and punch displacement (e) are used to model the springback for air bending of high-strength sheet metal using the genetic algorithm (GA) and back propagation neural network (BPNN) approach, where the positive model and reverse model of springback prediction are established, respectively, with GA and BPNN. Adopting the "object-positive model-reverse model" learning method, air bending springback law is studied with positive model and punch radius is predicted by reverse model. Manifested by the experiment for air bending forming of a workpiece used as crane boom, the prediction method proposed yields satisfactory effect in sheet metal air bending forming and punch design. © 2010 Springer-Verlag London Limited.


Wu M.,Huazhong University of Science and Technology | Fu H.,Huazhong University of Science and Technology | Zhou L.,Miami University Ohio | Yao K.,Huazhong University of Science and Technology | Zeng X.C.,University of Nebraska - Lincoln
Nano Letters | Year: 2015

We predict a new class of monolayer phosphorus allotropes, namely, ε-P, ζ-P, η-P, and η-P. Distinctly different from the monolayer α-P (black) and previously predicted β-P (Phys. Rev. Lett. 2014, 112, 176802), γ-P, and δ-P (Phys. Rev. Lett. 2014, 113, 046804) with buckled honeycomb lattice, the new allotropes are composed of P4 square or P5 pentagon units that favor tricoordination for P atoms. The new four polymorphs, together with five additional hybrid polymorphs, greatly enrich the phosphorene structures, and their stabilities are confirmed by first-principles calculations. In particular, the η-P is shown to be equally stable as the α-P (black) and more stable than all previously reported phosphorene polymorphs. Prediction of nonvolatile ferroelastic switching and structural transformation among different polymorphs under strains points out their potential applications via strain engineering. © 2015 American Chemical Society.


Shen Y.,Huazhong University of Science and Technology | Wang J.,Huazhong University of Science and Technology | Wang J.,Chinese University of Hong Kong | Wang J.,Dalian University of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2012

In recent years, the global stability of recurrent neural networks (RNNs) has been investigated extensively. It is well known that time delays and external disturbances can derail the stability of RNNs. In this paper, we analyze the robustness of global stability of RNNs subject to time delays and random disturbances. Given a globally exponentially stable neural network, the problem to be addressed here is how much time delay and noise the RNN can withstand to be globally exponentially stable in the presence of delay and noise. The upper bounds of the time delay and noise intensity are characterized by using transcendental equations for the RNNs to sustain global exponential stability. Moreover, we prove theoretically that, for any globally exponentially stable RNNs, if additive noises and time delays are smaller than the derived lower bounds arrived at here, then the perturbed RNNs are guaranteed to also be globally exponentially stable. Three numerical examples are provided to substantiate the theoretical results. © 2012 IEEE.


Liu K.,University of Sheffield | Zhu Z.Q.,University of Sheffield | Zhang Q.,Huazhong University of Science and Technology | Zhang J.,Hunan University
IEEE Transactions on Industrial Electronics | Year: 2012

This paper investigates the influence of nonideal voltage measurements on the parameter estimation of permanentmagnet synchronous machines (PMSMs). The influence of nonideal voltage measurements, such as the dc bus voltage drop, zero shift in the amplifier, and voltage source inverter nonlinearities, on the estimation of different machine parameters is investigated by theoretical and experimental analysis. For analysis, a model-reference-adaptive-system-based estimator is first described for the parameter estimation of the q-axis inductance, stator winding resistance, and rotor flux linkage. The estimator is then applied to a prototype surface-mounted PMSM to investigate the influence of nonideal voltage measurement on the estimation of various machine parameter values. It shows that, at low speed, the inverter nonlinearity compensation has significant influence on both the rotor flux linkage and winding resistance estimations while, at high speed, it has significant influence only on the winding resistance estimation and has negligible influence on the rotor flux linkage estimation. In addition, the inverter nonlinearity compensation will not influence the q-axis inductance estimation when it is under id = 0 control. However, the dc bus voltage drop due to the load variation and zero shift in the amplifier will significantly influence the q-axis inductance estimation. © 2011 IEEE.


Yin H.,Huazhong University of Science and Technology | Yin H.,Eurecom | Gesbert D.,Eurecom | Filippou M.,Eurecom | Liu Y.,Huazhong University of Science and Technology
IEEE Journal on Selected Areas in Communications | Year: 2013

This paper addresses the problem of channel estimation in multi-cell interference-limited cellular networks. We consider systems employing multiple antennas and are interested in both the finite and large-scale antenna number regimes (so-called "massive MIMO"). Such systems deal with the multi-cell interference by way of per-cell beamforming applied at each base station. Channel estimation in such networks, which is known to be hampered by the pilot contamination effect, constitutes a major bottleneck for overall performance. We present a novel approach which tackles this problem by enabling a low-rate coordination between cells during the channel estimation phase itself. The coordination makes use of the additional second-order statistical information about the user channels, which are shown to offer a powerful way of discriminating across interfering users with even strongly correlated pilot sequences. Importantly, we demonstrate analytically that in the large-number-of-antennas regime, the pilot contamination effect is made to vanish completely under certain conditions on the channel covariance. Gains over the conventional channel estimation framework are confirmed by our simulations for even small antenna array sizes. © 2012 IEEE.


News Article | November 15, 2015
Site: www.techtimes.com

Chinese researchers have developed a special material capable of making stealth jets and ships harder to detect using anti-stealth radar. The development of the technology shows China catching up in an area of defense traditionally dominated by the United States. The material, known as active frequency selecting surface, or AFSS, is covered with a substance used in printed circuit boards. AFSS has the ability to adapt to different radar frequencies and react to them, much like a radio wave counterpart of a chameleon skin. While there are existing stealth materials that can absorb microwaves fired by radars, these are thick and heavy to use. The new material is far thinner and lighter compared to the conventional ones, which offer advantageous implications in terms of use. "Our proposed absorber is almost ten times thinner than conventional ones," said Wenhua Xu, from China's Huazhong University of Science and Technology, said. Typical airplanes hide their appearance using body geometry, which reflects radio waves away from the receivers, and wave-absorbing materials that turn waves into heat instead of reflecting them back. Utilized by the Pentagon to protect fighter planes, this can be disadvantageous because newer radar technologies use ultra-high-frequency (UHF) radar, which can detect traces of the plane missed by other radar. The new aircraft developed by the Chinese researchers consists of a thin material just 5/16 of an inch, protecting stealth planes against UFH detection. The AFSS adapts to range of detection frequencies, effectively concealing itself from radar scans. "In this paper, we present an ultra-thin broadband AFSS absorber with a stretching transformation (ST) pattern for use in UHF applications," the researchers wrote in their study published in the Journal of Applied Physics. "As radar detection equipment continues to improve, our thin absorbers with broad bandwidth and working in the UHF band will be widely useful." It is not clear if China's military has already adopted this technology on the Chengdu J-20 and the Shenyang J-31, two of its stealth jets. No confirmations have been made as to its plans to advance the technology. Nevertheless, the breakthrough can potentially boost the capability of the Chinese military, air- and sea-wise. Many consider stealth to be one of the key technologies that allowed for the dominance of the U.S. military over the last century. The method effectively neutralized and offset the technological gains made by other nations.


For the first time, Stretching Transformation is applied to the unit cell pattern to expand the tunable bandwidth. With this technique, it is realizable to be thin and achieve broadband absorption simultaneously. Credit: Intelligent Electronics Institute, Huazhong University of Sci&Tec. Microwave absorbers are a kind of material that can effectively absorb incident microwave energy to make objects invisible to radar; therefore they are commonly used in aircraft cloaking and warship stealth. Recently, as radar detection devices have been improved to detect the near-meter microwave length regime, scientists are working on high-performance absorbers that can cloak objects in the equivalent ultra-high frequency regime (from 300 megahertz to two gigahertz). However, conventional absorbers for the ultra-high regime are usually thick, heavy or have narrow absorption bandwidth, making them unsuitable for stealth missions. To solve this problem, a team of researchers from Huazhong University of Science and Technology in China has developed an ultra-thin, tunable broadband microwave absorber for ultra-high frequency applications. This ultra-thin absorbing surface, called an active frequency-selective surface absorber, consists of arrays of patterned conductors loaded with two common types of circuit elements known as resistors and varactors. The unit patterned cell absorbs microwaves and can also be actively controlled by stretching to expand the tunable bandwidth. In a paper published this week in the Journal of Applied Physics, the researchers presented this work. "Our proposed absorber was fabricated with a stretching transformation pattern, which is both thin and can absorb a wide range of frequencies for near-meter microwave application," said Wenhua Xu, the primary researcher in the team led by Jianjun Jiang, a professor of School of Optical and Electronic Information at the Huazhong University of Science and Technology, China. "Its absorption range covers a broad band from 0.7 to 1.9 gigahertz below -10 decibel, and the total thickness of the absorber is only 7.8 millimeters, which is one of the thinnest microwave absorbers reported." "Usually the thickness of conventional radar absorbers is a quarter the wavelength of the incident microwave. In the high frequency regime, take one gigahertz as an example, the thickness of the absorber would be around 7.5 centimeters, which is too thick and heavy to be used in aircrafts or warships. Our proposed absorber is almost ten times thinner than conventional ones," Xu said. Other alternative absorbers, such as metamaterial absorbers made from a resonant metallic structure printed on a dielectric substrate, though significantly thinner than the wavelengths absorbed, have a narrow working bandwidth. To develop a novel absorber that is both thin and with broadband performance, Jiang's team employed a type of thin, light periodic structure called a frequency-selective surface, which consists of an assembly of patterned conductors arranged in a two-dimensional array, usually backed by a thin dielectric, to reflect incident microwaves according to their frequency. In the experiment, Jiang's team fabricated a broadband active frequency-selective surface with a stretching transformation pattern on a printed circuit board, and soldered the resistors and varactors between each of the two unit patterned cells. The fact that the surface could be stretched meant that the parameters of the unit patterned cell can be actively controlled by stretching. By modeling the absorber using a transmission line, the researchers found that the varactor provides a variable capacitance at varying bias voltage, which produces the device's tunability, while the lumped resistor with constant resistance reliably produces strong absorption at the resonance frequency. Besides the lumped impedances of the loaded elements, the researchers discovered that the parameters of the unit patterned cells contribute to the device's absorption performance as well. "We applied various stretching transformation coefficients to the unit cell pattern to obtain the available parameters to expand the tunable bandwidth," Xu said. "Our results suggest that a cell pattern with a smaller stretching transformation coefficients ratio (i.e. width to length ratio of the unit cell) leads to higher resonance frequency absorption and produces a wider tunable bandwidth as well." Xu noted that it is the first time that stretching transformation pattern is used in the active frequency-selective surface absorber to expand the bandwidth, which turns out to be an effective technique for producing broadband tunability. "At frequencies below two gigahertz, conventional microwaves absorbers are limited in application by their thickness and narrow absorption bandwidth. Our proposed absorber has achieved broadband tunability and ultra-thin film simultaneously," Xu said. "The total thickness of 7.8 millimeters is around one twenty-ninth wavelength of the central frequency of incident microwaves, and the ultra-thin absorber with broad bandwidth may be widely used in warship stealth, airplane cloaking and tunable, broadband antennae." The researchers' next step is to study the polarization and the oblique incidence performance for the proposed active frequency-selective surface absorber. Explore further: Physicists study how to achieve perfect absorption of light with the help of rough ultrathin films More information: "An ultra-thin broadband active frequency-selective surface absorber for ultrahigh-frequency applications" by Wenhua Xu, Yun He, Peng Kong, Jialin Li, Haibing Xu, Ling Miao, Shaowei Bie and Jianjun Jiang, Journal of Applied Physics , November 10, 2015. DOI: 10.1063/1.4934683 , http://scitation.aip.org/content/aip/journal/jap/118/18/10.1063/1.4934683.


Bernardes M.A.D.S.,Centro Universitario | Zhou X.,Huazhong University of Science and Technology
Solar Energy | Year: 2013

This paper evaluates the Solar Chimney Power Plant performance subject to adverse solar radiance conditions. For that, numerical simulations are performed to estimate the optimal ratio of the turbine pressure drop to the total pressure potential (. x-factor) as an independent control variable. The results show that x-factor values remain around 0.8 for periods with sufficient heat gain from sun or ground. Otherwise, x-factor values have a tendency to drop to zero. In winter, due to lower system heat gains, this trend is more accentuated. © 2013 Elsevier Ltd.


Rao L.,McGill University | Liu X.,McGill University | Xie L.,Texas A&M University | Liu W.,Huazhong University of Science and Technology
IEEE Transactions on Smart Grid | Year: 2012

This paper addresses the problem of electricity cost management for Internet service providers with a collection of spatially distributed data centers. As the demand on Internet services drastically increases in recent years, the electricity consumed by Internet data centers (IDCs) has been skyrocketing. While most existing research focuses on reducing electric energy consumption of IDCs at one specific location, the problem of reducing the total electricity cost has been overlooked. This is an important problem faced by service providers, especially in the present multi-electricity-market environment, where the price of electricity may exhibit temporal and spatial diversities. Further, for these service providers, guaranteeing the quality of service (i.e., service level objectives) such as service delay guarantees to the end users is of critical importance. This paper studies the problem of minimizing the total electricity cost under multiple electricity markets environment while guaranteeing the quality of service geared to the location diversity and time diversity of electricity price. The problem is modeled as a constrained mixed-integer programming and an efficient solution algorithm is proposed. Extensive evaluations based on real-world electricity price data for multiple IDC locations illustrate the efficiency and efficacy of our approach. © 2011 IEEE.


Xia Q.,Huazhong University of Science and Technology | Wang M.Y.,Chinese University of Hong Kong | Shi T.,Huazhong University of Science and Technology
Computer Methods in Applied Mechanics and Engineering | Year: 2015

The topology optimization problem with pressure load is solved by using a level set method. The free boundary and the pressure boundary of a structure are represented separately as two zero-level sets of two level set functions, and they are independently propagated during the optimization by solving two Hamilton-Jacobi equations. In order to prevent the two boundaries from touching or crossing each other, the design velocities of the two boundaries that amount to the steepest descent directions are modified. The optimization problem of minimum compliance with perimeter regularization is considered. The shape derivatives of the two boundaries are derived by using the material derivative approach and the adjoint method. The finite element analysis is done through an Eulerian method by employing a fixed mesh and an artificial weak material that represents void. Numerical examples in two dimensions are investigated. © 2014 Elsevier B.V.


Xia Q.,Huazhong University of Science and Technology | Wang M.Y.,Chinese University of Hong Kong | Shi T.,Huazhong University of Science and Technology
Computer Methods in Applied Mechanics and Engineering | Year: 2014

We present a level set method for the shape and topology optimization of both structure and support. Two level set functions are used to implicitly represent a structure. The traction free boundary and the Dirichlet boundary are represented separately and are allowed to be continuously changed during the optimization. The optimization problem of minimum compliance is considered. The shape derivatives of both boundaries are derived by using a Lagrangian function and the adjoint method. The finite element analysis is done by modifying a fixed background mesh, and we do not use the artificial weak material. Numerical examples in two dimensions are investigated. © 2014 Elsevier B.V.


Zhou T.,Hangzhou Dianzi University | Lu Y.,Huazhong University of Science and Technology | Wang B.,University of Texas–Pan American
Computers in Human Behavior | Year: 2010

Due to its advantages such as ubiquity and immediacy, mobile banking has attracted traditional banks' interests. However, a survey report showed that user adoption of mobile banking was much lower than that of other mobile services. The extant research focuses on explaining user adoption from technology perceptions such as perceived usefulness, perceived ease of use, interactivity, and relative advantage. However, users' adoption is determined not only by their perception of the technology but also by the task technology fit. In other words, even though a technology may be perceived as being advanced, if it does not fit users' task requirements, they may not adopt it. By integrating the task technology fit (TTF) model and the unified theory of acceptance and usage of technology (UTAUT), this research proposes a mobile banking user adoption model. We found that performance expectancy, task technology fit, social influence, and facilitating conditions have significant effects on user adoption. In addition, we also found a significant effect of task technology fit on performance expectancy. © 2009 Elsevier Ltd. All rights reserved.


Lu Y.,Huazhong University of Science and Technology | Zhao L.,Huazhong University of Science and Technology | Wang B.,University of Texas–Pan American
Electronic Commerce Research and Applications | Year: 2010

In China, major C2C websites are focusing on increasing their customer bases by converting members of their virtual communities (VCs) into C2C buyers and sellers. This phenomenon is called e-commerce based on social networks (ENS). The current research analyzes what factors affect trust building among VC members and how this trust influences the trust in the C2C website or vendor. We propose and empirically test a model of trust in VCs based on the trust formation mechanism. Using data collected from Taobao Virtual Community, we show that familiarity, perceived similarity, structural assurance, and trust propensity are important antecedents to trust in members in VCs. Analyses of the two kinds of trust show that trust in members' ability significantly affects three dimensions of trust in the vendor/website in terms of ability, integrity, and benevolence. In addition, trust in members' integrity and benevolence stimulates the purchase intention and trust in the vendor/website's ability positively affects the intention to get information and the purchase intention. © 2009 Elsevier B.V. All rights reserved.


Leung C.C.,Center for Health Protection | Yu I.T.S.,Chinese University of Hong Kong | Chen W.,Huazhong University of Science and Technology
The Lancet | Year: 2012

Silicosis is a fibrotic lung disease caused by inhalation of free crystalline silicon dioxide or silica. Occupational exposure to respirable crystalline silica dust particles occurs in many industries. Phagocytosis of crystalline silica in the lung causes lysosomal damage, activating the NALP3 inflammasome and triggering the inflammatory cascade with subsequent fibrosis. Impairment of lung function increases with disease progression, even after the patient is no longer exposed. Diagnosis of silicosis needs carefully documented records of occupational exposure and radiological features, with exclusion of other competing diagnoses. Mycobacterial diseases, airway obstruction, and lung cancer are associated with silica dust exposure. As yet, no curative treatment exists, but comprehensive management strategies help to improve quality of life and slow deterioration. Further efforts are needed for recognition and control of silica hazards, especially in developing countries.


Xiong H.,Huazhong University of Science and Technology | Si L.-G.,Huazhong University of Science and Technology | Lu X.-Y.,RIKEN | Yang X.,Huazhong University of Science and Technology | Wu Y.,Huazhong University of Science and Technology
Optics Letters | Year: 2013

We analyze the features of the output field of a generic optomechanical system that is driven by a control field and a nanosecond driven pulse, and find a robust high-order sideband generation in optomechanical systems. The typical spectral structure, plateau and cutoff, confirms the nonperturbative nature of the effect, which is similar to highorder harmonic generation in atoms or molecules. Based on the phenomenon, we show that the carrier-envelope phase of laser pulses that contain huge numbers of cycles can cause profound effects. © 2013 Optical Society of America.


Wu M.,Huazhong University of Science and Technology | Zeng X.C.,University of Nebraska - Lincoln
Nano Letters | Year: 2016

Phosphorene and phosphorene analogues such as SnS and SnSe monolayers are promising nanoelectronic materials with desired bandgap, high carrier mobility, and anisotropic structures. Here, we show first-principles calculation evidence that these monolayers are potentially the long-sought two-dimensional (2D) materials that can combine electronic transistor characteristic with nonvolatile memory readable/writeable capability at ambient condition. Specifically, phosphorene is predicted to be a 2D intrinsic ferroelastic material with ultrahigh reversible strain, whereas SnS, SnSe, GeS, and GeSe monolayers are multiferroic with coupled ferroelectricity and ferroelasticity. Moreover, their low-switching barriers render room-temperature nonvolatile memory accessible, and their notable structural anisotropy enables ferroelastic or ferroelectric switching readily readable via electrical, thermal, optical, mechanical, or even spintronic detection upon the swapping of the zigzag and armchair direction. In addition, it is predicted that the GeS and GeSe monolayers as well as bulk SnS and SnSe can maintain their ferroelasticity and ferroelectricity (anti-ferroelectricity) beyond the room temperature, suggesting high potential for practical device application. © 2016 American Chemical Society.


Fu Y.-S.,Huazhong University of Science and Technology | Kawamura M.,Huazhong University of Science and Technology | Igarashi K.,Tokyo Institute of Technology | Takagi H.,RIKEN | And 4 more authors.
Nature Physics | Year: 2014

Massless Dirac electrons in condensed matter are, unlike conventional electrons, described by two-component wavefunctions associated with the spin degrees of freedom in the surface state of topological insulators. Hence, the ability to observe the two-component wavefunction is useful for exploring novel spin phenomena. Here we show that the two-component nature is manifest in Landau levels, the degeneracy of which is lifted by a Coulomb potential. Using spectroscopic-imaging scanning tunnelling microscopy, we visualize energy and spatial structures of Landau levels in Bi 2 Se 3, a prototypical topological insulator. The observed Landau-level splitting and internal structures of Landau orbits are distinct from those in a conventional electron system and are well reproduced by a two-component model Dirac Hamiltonian. Our model further predicts energy-dependent spin-magnetization textures in a potential variation and provides a way for manipulating spins in the topological surface state. © 2014 Macmillan Publishers Limited.


Shen X.,South-Central University for Nationalities | Zhu L.,Huazhong University of Science and Technology | Wang N.,Huazhong University of Science and Technology | Ye L.,Lund University | Tang H.,South-Central University for Nationalities
Chemical Communications | Year: 2012

Molecular imprinting technology allows synthesis of polymers with specific recognition ability towards target pollutants, which show potential to selectively remove Highly Toxic Organic Pollutants (HTOPs) in the presence of common organic matrices that are thousands of times more abundant than the targets. This feature article summarizes the current development of molecular imprinting for removing HTOPs from polluted water, with a special emphasis on the application of molecularly imprinted polymers to improve the efficiency of photocatalytic and biological degradation of HTOPs in wastewater.


Caliskan-Demirag O.,Pennsylvania State University | Chen Y.,Chinese University of Hong Kong | Li J.,Huazhong University of Science and Technology
International Journal of Production Economics | Year: 2011

In a supply chain setting, we analyze a manufacturers customer and retailer rebates, which are sales incentives offered to the end buyers and retailers, respectively. The performance of both rebates is influenced by the retailers objective and response to the promotion due to his intermediary position in the channel. Earlier studies investigating rebates in distribution channels have traditionally assumed that the retailer is risk neutral with the objective of maximizing expected profits. In our paper, we consider a risk-averse retailer. We formally model risk aversion by adopting the Conditional-Value-at-Risk (CVaR) decision criterion. Using a stochastic and (effective) price dependent demand, we analyze the manufacturers rebate amount decisions and the retailers joint inventory and pricing decisions in a game theoretical framework. We provide several structural properties of the objective functions and show monotonicity of the retailers decisions in the degree of risk aversion. For the case of retailer rebates, we characterize the unique equilibrium, and for the case of customer rebates, we prove the existence of an equilibrium. Using numerical examples, we provide further insights on the impact of risk aversion. For example, given an exogenous wholesale price, we observe a threshold value on the retailers risk-aversion parameter below (above) which the manufacturer is better off with retailer rebates (customer rebates); implying that the manufacturers preferred rebate type can be different depending on whether the retailer is risk neutral or sufficiently risk averse. © 2011 Elsevier B.V. All right reserved.


Barber S.L.,WHO | Yao L.,Huazhong University of Science and Technology
International Journal of Health Planning and Management | Year: 2011

Health insurance programs have changed rapidly over time in China. Among rural populations, insurance coverage shifted from nearly universal levels in the 1970s to 7% in 1999; it stands at 94% of counties in 2009. This large increase is the result of a series of health reforms that aim to achieve universal access to healthcare and better risk protection, largely through the rollout of the health insurance programs and the gradual increase in subsidies and benefits over time. In this paper, we present the development of the rural and urban health insurance programs, their modes of financing and operation and the benefits and reimbursement schemes at the end of 2009. We discuss some of the problems with the rural and urban residents' schemes including reliance on local government capacity, reimbursement ceilings and rates, and incentives for unnecessary care and waste in the design of the programs. Recommendations include increasing financial support and deepening the benefits packages. Strategies to control cost and improve quality include developing mixed provider payment mechanisms, implementing essential medicines policies and strengthening the quality of primary-care provision. © 2011 John Wiley & Sons, Ltd.


Li J.,McGill University | Huang T.,Huazhong University of Science and Technology | Chen L.R.,McGill University
IEEE Journal on Selected Topics in Quantum Electronics | Year: 2012

We demonstrate all-optical clock recovery of input return-to-zero ON-OFF-keyed signals operating at 10 Gb/s using a fiber optical parametric oscillator (FOPO). We first characterize an actively mode-locked FOPO, which serves as the basis for all-optical clock recovery. 12.5-ps pulses with a timing jitter of around 450 fs are generated. Afterward, the characteristics of the recovered clock (timing jitter, pulsewidth, and time-bandwidth product) are investigated as a function of the duty cycle, average power, extinction ratio, and optical signal to noise ratio (OSNR) of the input signal. The wavelength tunability of the recovered clock is also investigated. The results show that the FOPO can recover a good quality clock over a large range of input signal characteristics, namely, duty cycle from 33% to 60%, average input power from-23 to 6 dBm, extinction ratio above 8.7 dB, and an OSNR larger than 27 dB. The wavelength of the recovered clock signal can be tunable over 8 nm. © 2011 IEEE.


News Article | June 10, 2014
Site: www.techtimes.com

A new kind of solar-sensitive nanoparticles could create flexible and efficient solar cells, possible making the technology available to consumers on a huge scale, Canadian researchers say. The newly designed nanoparticle, dubbed a "colloidal quantum dot," makes use of two kinds of semiconductors, of which one has an unfortunate tendency to break down when it's exposed to air, losing its electrons and its ability to generate electricity, they said. University of Toronto researchers say they've solved that dilemma by creating a nanoparticle "dot" that does will bind with oxygen during exposure to air. Such quantum dots, being much more stable, could lead to solar cells that are more flexible and cheaper to manufacture to use in a number of different applications, they said. "Colloidal quantum dots (CQDs) offer promise in flexible electronics, light sensing and energy conversion," the researchers wrote in the journal Nature Materials. By boosting light absorption, they could also be used in other technical applications and optoelectrical devices combing electricity and light such as infrared lasers, gas sensors, or infrared light-emitting diodes, they said. They could also lead to advances in "weather satellites, remote controllers, satellite communication, or pollution detectors," they wrote. "This is a material innovation, that's the first part, and with this new material we can build new device structures," post-doctoral researcher Zhijun Ning said. Once the technology is refined, the researchers said, the quantum dots could even be mixed with inks for printed surfaces, into paint,  or applied to flexible substrates such as roof shingles to create solar power for millions around the world at an affordable cost. The new quantum dot material has achieved conversion efficiently for solar power of up to eight percent, the researchers said, among the best results from similar technology reported to date. "The field of colloidal quantum dot photovoltaics requires continued improvement in absolute performance, or power conversion efficiency," says Toronto researcher Ted Sargent, in the university's Edward S. Rogers Sr. Department of Electrical & Compute Engineering. "The field has moved fast, and keeps moving fast, but we need to work toward bringing performance to commercially compelling levels." Participating in the Toronto research were scientists from Dalhousie University in Nova Scotia, King Abdulla University of Science and Technology in Saudi Arabia and Huazhong University of Science and Technology in China.


Wang Y.,Tulane University | Wang Y.,Huazhong University of Science and Technology | Han C.,Tulane University | Lu L.,Tulane University | And 2 more authors.
Hepatology | Year: 2013

Hedgehog (Hh) signaling plays an important role in embryonic development and in the regulation of a variety of cellular functions. Aberrant activation of Hh signaling has been implicated in several human cancers including hepatocellular carcinoma (HCC). In this study we examined the pathobiological functions and molecular mechanisms of the Hh signaling pathway in HCC cells. Treatment of cultured human HCC cells (Huh7, Hep3B, and HepG2) with the Hh signaling ligand (recombinant Shh) or agonist, SAG and purmorphamine, prevented the induction of autophagy. In contrast, GANT61 (a small molecule inhibitor of Gli1 and Gli2) induced autophagy, as determined by immunoblotting for microtubule-associated protein light chain 3 (LC3) and p62, GFP-LC3 puncta, monodansylcadaverine (MDC) staining, and transmission electron microscopy. Hh inhibition-induced autophagy was associated with up-regulation of Bnip3, as determined by immunoblotting and real-time polymerase chain reaction (PCR) assay. Knockdown of Bnip3 by RNAi impaired GANT61-induced autophagy. Additionally, Hh inhibition-induced autophagy was associated with Bnip3-mediated displacement of Bcl-2 from Beclin-1, as determined by immunoblotting and immunoprecipitation assays. Furthermore, inhibition of Hh signaling increased HCC cell apoptosis and decreased cell viability, as determined by caspase and WST-1 assays. Pharmacological or genetic inhibition of autophagy by 3-methyladenine (3-MA) or Beclin-1 small interfering RNA (siRNA) partially suppressed GANT61-induced cell apoptosis and cytotoxicity. In a tumor xenograft model using SCID mice inoculated with Huh7 cells, administration of GANT61 inhibited tumor formation and decreased tumor volume; this effect was partially blocked by the autophagy inhibitor, 3-MA. Conclusion: These findings provide novel evidence that Hh inhibition induces autophagy through up-regulation of Bnip3 and that this mechanism contributes to apoptosis. Therefore, the status of autophagy is a key factor that determines the therapeutic response to Hh-targeted therapies. (Hepatology 2013;53:995-1010). © 2013 by the American Association for the Study of Liver Diseases.


Xu F.,Huazhong University of Science and Technology | Liu F.,Huazhong University of Science and Technology | Jin H.,Huazhong University of Science and Technology | Vasilakos A.V.,Kuwait University
Proceedings of the IEEE | Year: 2014

Infrastructure-as-a-Service (IaaS) cloud computing offers customers (tenants) a scalable and economical way to provision virtual machines (VMs) on demand while charging them only for the leased computing resources by time. However, due to the VM contention on shared computing resources in datacenters, this new computing paradigm inevitably brings noticeable performance overhead (i.e., unpredictable performance) of VMs to tenants, which has become one of the primary issues of the IaaS cloud. Consequently, increasing efforts have recently been devoted to guaranteeing VM performance for tenants. In this survey, we review the state-of-the-art research on managing the performance overhead of VMs, and summarize them under diverse scenarios of the IaaS cloud, ranging from the single-server virtualization, a single mega datacenter, to multiple geodistributed datacenters. Specifically, we unveil the causes of VM performance overhead by illustrating representative scenarios, discuss the performance modeling methods with a particular focus on their accuracy and cost, and compare the overhead mitigation techniques by identifying their effectiveness and implementation complexity. With the obtained insights into the pros and cons of each existing solution, we further bring forth future research challenges pertinent to the modeling methods and mitigation techniques of VM performance overhead in the IaaS cloud. © 2013 IEEE.


Zhang X.,Henan University of Technology | Zhou J.,Huazhong University of Science and Technology
Mechanical Systems and Signal Processing | Year: 2013

This study presents a novel procedure based on ensemble empirical mode decomposition (EEMD) and optimized support vector machine (SVM) for multi-fault diagnosis of rolling element bearings. The vibration signal is adaptively decomposed into a number of intrinsic mode functions (IMFs) by EEMD. Two types of features, the EEMD energy entropy and singular values of the matrix whose rows are IMFs, are extracted. EEMD energy entropy is used to specify whether the bearing has faults or not. If the bearing has faults, singular values are input to multi-class SVM optimized by inter-cluster distance in the feature space (ICDSVM) to specify the fault type. The proposed method was tested on a system with an electric motor which has two rolling bearings with 8 normal working conditions and 48 fault working conditions. Five groups of experiments were done to evaluate the effectiveness of the proposed method. The results show that the proposed method outperforms other methods both mentioned in this paper and published in other literatures. © 2013 Elsevier Ltd.


Liu X.,Huazhong University of Science and Technology | Gong H.,Huazhong University of Science and Technology | Huang K.,Huazhong University of Science and Technology | Huang K.,Wuhan Institute of Biotechnology
Cancer Science | Year: 2013

The kinesin superfamily (KIF) is a group of proteins that share a highly conserved motor domain. Except for some members, many KIF proteins have adenosine triphosphatase activity and microtubule-dependent plus-end motion ability. Kinesins participate in several essential cellular functions, including mitosis, meiosis and the transport of macromolecules. Increasing evidence indicates kinesin proteins play critical roles in the genesis and development of human cancers. Some kinesin proteins are associated with maligancy as well as drug resistance of solid tumor. Thus, targeting KIF therapy seems to be a promising anticancer strategy. Inhibitors of KIF such as kinesin spindle protein (KSP/Eg5) have entered clinical trials for monotherapy or in combination with other drugs, and kinesins other than Eg5 with various potential anticancer target characteristics are also constantly being discovered and studied. Here, we summarize the oncogenic roles of kinesin proteins and potential cancer therapy strategies that target KIF. © 2013 © 2013 Japanese Cancer Association.


Xu G.,Huazhong University of Science and Technology | Wang W.,Huazhong University of Science and Technology | Zhou M.,Ohio State University
Hippocampus | Year: 2014

Similar to astrocytes, NG2 glial cells are uniformly distributed in the central nervous system (CNS). However, little is known about the interspatial relationship, nor the functional interactions between these two star-shaped glial subtypes. Confocal morphometric analysis showed that NG2 immunostained cells are spatially organized as domains in rat hippocampal CA1 region and that each NG2 glial domain occupies a spatial volume of ~178, 364 μm3. The processes of NG2 glia and astrocytes overlap extensively; each NG2 glial domain interlaces with the processes deriving from 5.8±0.4 neighboring astrocytes, while each astrocytic domain accommodates processes stemming from 4.5±0.3 abutting NG2 glia. In CA1 stratum radiatum, the cell bodies of morphologically identified glial cells often appear to make direct somatic-somata contact, termed as doublets. We used dual patch recording and postrecording NG2/GFAP double staining to determine the glial identities of these doublets. We show that among 44 doublets, 50% were NG2 glia-astrocyte pairs, while another 38.6% and 11.4% were astrocyte-astrocyte and NG2 glia-NG2 glia pairs, respectively. In dual patch recording, neither electrical coupling nor intercellular biocytin transfer was detected in astrocyte-NG2 glia or NG2 glia-NG2 glia doublets. Altogether, although NG2 glia and astrocytes are not gap junction coupled, their cell bodies and processes are interwoven extensively. The anatomical and physiological relationships revealed in this study should facilitate future studies to understand the metabolic coupling and functional communication between NG2 glia and astrocytes. © 2013 Wiley Periodicals, Inc.


Chen J.,Huazhong University of Science and Technology | Zeng Z.,Huazhong University of Science and Technology | Zeng Z.,Key Laboratory of Image Processing and Intelligent Control of Education Ministry of China | Jiang P.,Huazhong University of Science and Technology
Neural Networks | Year: 2014

The present paper introduces memristor-based fractional-order neural networks. The conditions on the global Mittag-Leffler stability and synchronization are established by using Lyapunov method for these networks. The analysis in the paper employs results from the theory of fractional-order differential equations with discontinuous right-hand sides. The obtained results extend and improve some previous works on conventional memristor-based recurrent neural networks. © 2013.


Deng W.-T.,Huazhong University of Science and Technology | Huang X.-G.,Fudan University
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

The non-central Cu. +. Au collisions can create strong out-of-plane magnetic fields and in-plane electric fields. By using the HIJING model, we study the general properties of the electromagnetic fields in Cu. +. Au collisions at 200GeV and their impacts on the charge-dependent two-particle correlator γq1q2=〈cos(ϕ1+ϕ2-2ψRP)〉 (see main text for definition) which was used for the detection of the chiral magnetic effect (CME). Compared with Au. +. Au collisions, we find that the in-plane electric fields in Cu. +. Au collisions can strongly suppress the two-particle correlator or even reverse its sign if the lifetime of the electric fields is long. Combining with the expectation that if γq1q2 is induced by elliptic-flow driven effects we would not see such strong suppression or reversion, our results suggest to use Cu. +. Au collisions to test CME and understand the mechanisms that underlie γq1q2. © 2015 Elsevier Inc.


Wu Y.,University of Toronto | Wu Y.,Huazhong University of Science and Technology | Satkunendrarajah K.,University of Toronto | Fehlings M.G.,University of Toronto
Neuroscience | Year: 2014

The spinal cord is vulnerable to ischemic injury due to trauma, vascular malformations and correction of thoracic aortic lesions. Riluzole, a sodium channel blocker and anti-glutamate drug has been shown to be neuroprotective in a model of ischemic spinal cord injury, although the effects in clinically relevant ischemia/reperfusion models are unknown. Here, we examine the effect of riluzole following ischemia-reperfusion injury to the spinal cord.Female rats underwent high thoracic aortic balloon occlusion to produce an ischemia/reperfusion injury. Tolerance to ischemia was evaluated by varying the duration of occlusion. Riluzole (8. mg/kg) was injected intraperitoneally 4. h after injury. Locomotor function (Basso, Beattie and Bresnahan (BBB) scale) was assessed at 4. h, 1. day, and 5. days post-ischemia. Spinal cords were extracted and evaluated for neuronal loss using immunohistology (choline acetyltransferase (ChAT) and neuronal nuclei (NeuN)), inflammation (CD11b), astrogliosis (glial fibrillary acidic protein - GFAP) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL).Ischemic injury lasting between 5.5 and 6.75. min resulted in delayed paraplegia, whereas longer ischemia induced immediate paraplegia. When riluzole was administered to rats that underwent 6. min of occlusion, delayed paraplegia was prevented. The BBB score of riluzole-treated rats was 11.14. ±. 4.85 compared with 1.86. ±. 1.07 in control animals. Riluzole also reduced neuronal loss, infiltration of microglia/macrophages and astrogliosis in the ventral horn and intermediate zone of the gray matter. In addition, riluzole reduced apoptosis of neurons in the dorsal horn of the gray matter.Riluzole has a neuroprotective effect in a rat model of spinal cord injury/reperfusion when administered up to 4. h post-injury, a clinically relevant therapeutic time window. © 2014 IBRO.


Zhao Z.,Huazhong University of Science and Technology | Wang J.,Huazhong University of Science and Technology | Li S.,Huazhong University of Science and Technology | Willner A.E.,University of Southern California
Optics Letters | Year: 2013

We propose a simple approach to broadband generation of orbital angular momentum (OAM) carrying vector beams based on compact metamaterials. It consists of two concentric rings in a gold film, where each ring is composed of subwavelength rectangular apertures with gradually varied orientation. The subwavelength rectangular aperture serves as a localized spatial polarizer. We show the generation of different OAM-carrying vector beams with OAM charge number and polarization order varying from -3 to +3 using a 11.2 × 11.2 μm device. The extinction ratio can exceed 20 dB, and the operation bandwidth (1500 nm) can cover from 1000 to 2500 nm (from near-infrared to mid-infrared). The device provides three degrees of freedom (polarization order l, polarization of input beam σ, and initial orientation angle α0) to flexibly generate different OAM-carrying vector beams. We can use a single device to generate two OAM-carrying vector beams with opposite charge sign of OAM by simply controlling the polarization of the input beam. We further study the performance dependence of the designed metamaterials on the offset of the initial orientation angle, length, and width of the rectangular apertures. The obtained results indicate favorable fabrication tolerance. © 2013 Optical Society of America.


Yi Z.,Huazhong University of Science and Technology | Wang S.,Huazhong University of Science and Technology | Liu Y.,CAS Beijing National Laboratory for Molecular
Advanced Materials | Year: 2015

Since the report of the first diketopyrrolopyrrole (DPP)-based polymer semiconductor, such polymers have received considerable attention as a promising candidate for high-performance polymer semiconductors in organic thin-film transistors (OTFTs). This Progress Report summarizes the advances in the molecular design of high-mobility DPP-based polymers reported in the last few years, especially focusing on the molecular design of these polymers in respect of tuning the backbone and side chains, and discussing the influences of structural modification of the backbone and side chains on the properties and device performance of corresponding DPP-based polymers. This provides insights for the development of new and high-mobility polymer semiconductors. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Li Z.,Huazhong University of Science and Technology | Jiang Y.,Huazhong University of Science and Technology | Jiang Y.,Hubei Engineering University | Yuan L.,Huazhong University of Science and Technology | And 5 more authors.
ACS Nano | Year: 2015

For lithium-sulfur batteries, commercial application is hindered by the insulating nature of sulfur and the dissolution of the reaction intermediates of polysulfides. Here, we present an ordered meso-microporous core-shell carbon (MMCS) as a sulfur container, which combines the advantages of both mesoporous and microporous carbon. With large pore volume and highly ordered porous structure, the "core" promises a sufficient sulfur loading and a high utilization of the active material, while the "shell" containing microporous carbon and smaller sulfur acts as a physical barrier and stabilizes the cycle capability of the entire S/C composite. Such a S/MMCS composite exhibits a capacity as high as 837 mAh g-1 at 0.5 C after 200 cycles with a capacity retention of 80% vs the second cycle (a decay of only 0.1% per cycle), demonstrating that the diffusion of the polysulfides into the bulk electrolyte can be greatly reduced. We believe that the tailored highly ordered meso-microporous core-shell structured carbon can also be applicable for designing some other electrode materials for energy storage. © 2014 American Chemical Society.


Wang C.,Huazhong University of Science and Technology | Wang C.,Huanggang Normal University | Shen Y.,Huazhong University of Science and Technology
IET Control Theory and Applications | Year: 2012

This study investigates the problem of delay-dependent robust stability for uncertain stochastic systems with interval time-varying delay. No restrictions on the derivative of the time-varying delay are imposed, although lower and upper bounds of the delay interval are assumed to be known. By decomposing the delay interval into multiple equidistant subintervals, new Lyapunov-Krasovskii functionals are introduced on these intervals, which result in being much less conservative than most existing results in the literature. In addition, the reduction in the conservatism of the proposed stability criteria is also attributed to the free-weighting matrix technique and a newly proposed bounding condition, which is used to estimate the upper bound of stochastic differential of the Lyapunov-Krasovskii functional without neglecting any useful terms. All the stability criteria are formulated in the form of linear matrix inequalities (LMIs), which are dependent on the size of the time delay. Some numerical examples are given to show the less conservatism and applicability of the obtained results. Moreover, when the number of the divided subintervals increases, the corresponding criteria can provide an improvement on the results. © 2012 The Institution of Engineering and Technology.


Wang J.,University of Southern California | Wang J.,Huazhong University of Science and Technology | Yang J.-Y.,University of Southern California | Fazal I.M.,University of Southern California | And 8 more authors.
Nature Photonics | Year: 2012

The recognition in the 1990s that light beams with a helical phase front have orbital angular momentum has benefited applications ranging from optical manipulation to quantum information processing. Recently, attention has been directed towards the opportunities for harnessing such beams in communications. Here, we demonstrate that four light beams with different values of orbital angular momentum and encoded with 42.8 × 4 Gbit s-1 quadrature amplitude modulation (16-QAM) signals can be multiplexed and demultiplexed, allowing a 1.37 Tbit s-1 aggregated rate and 25.6 bit s-1 Hz-1 spectral efficiency when combined with polarization multiplexing. Moreover, we show scalability in the spatial domain using two groups of concentric rings of eight polarization-multiplexed 20 × 4 Gbit s-1 16-QAM-carrying orbital angular momentum beams, achieving a capacity of 2.56 Tbit s-1 and spectral efficiency of 95.7 bit s -1 Hz-1. We also report data exchange between orbital angular momentum beams encoded with 100 Gbit s-1 differential quadrature phase-shift keying signals. These demonstrations suggest that orbital angular momentum could be a useful degree of freedom for increasing the capacity of free-space communications. © 2012 Macmillan Publishers Limited. All rights reserved.


Akhmat G.,Huazhong University of Science and Technology | Zaman K.,COMSATS Institute of Information Technology | Shukui T.,Huazhong University of Science and Technology | Sajjad F.,COMSATS Institute of Information Technology
Renewable and Sustainable Energy Reviews | Year: 2014

This study is a contribution to the on-going debate over whether there is a relationship between energy consumption and climatic change variables, although the developed regions are among the most energy intensive economies in the world, little attention has been paid to the features of their energy consumption and climatic variations. Therefore, this study empirically investigates the two variables dynamic relationship in five broader regions of the world i.e., South Asia, Middle East and North Africa (MENA region), Sub-Saharan Africa, East Asia and Pacific and the aggregate data of the World. The major climatic variables include atmospheric, topographic, living organisms threatened; water system and growth factors are used to investigate energy-climate nexus over a period of 1975-2011. The results of the study indicate that there exists a long-run equilibrium relationship between energy consumption and climatic variables which shows climatic variations due to changes in energy consumption in different regions of the world. Although, the causality results are mixed among regions, we do find a systematic pattern. The present study find evident of unidirectional causality between the electric power consumption and climatic factors in the World's selected region. Sound and effective energy consumption strategy may reduce the burden of global warming situation in the world. © 2014 Elsevier Ltd.

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