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Hefei University of Technology is a major university in China, with particular strength in Engineering and Management Science. It is located in Hefei, the capital of the Anhui Province.Hefei University of Technology is a national key university administrated directly by the Ministry of Education. It has been listed in major national initiatives seeking to enhance the international competitiveness of the top-tier universities in China such as Project 211 and Project 985 Innovation Platform.Since its founding in 1945, it has been committed to cultivating talent with excellence, advancing science and technology, pushing social development, and promoting culture, with the spirit best manifested in the university motto "pursuing virtue and knowledge, seeking truth and innovation".HFUT has four campuses – Tunxilu, Lu'anlu, Feicuihu and Xuancheng – covering an area of about 3,417,390 m². The first three campuses are located in Hefei, the provincial capital of Anhui, and the fourth is in Xuancheng, a city about 194 kilometers away from Hefei.Campuses in Hefei have 19 schools covering a wide range of fields with a strong focus on engineering science. The schools offer 82 undergraduate programs, 32 first-level disciplines with authorization to confer master degrees, 12 first-level disciplines for doctoral programs as well as 12 post-doctoral programs. 4 disciplines are selected as national key disciplines and 28 are provincial key disciplines. The university has 1 state key lab, 1 national engineering lab, 4 national university-industry joint engineering research centers and 46 research centers at the ministerial or provincial level as well as 1 national A-level architectural design and research institute. The campus in Xuancheng has 5 departments.The university has a high-level faculty team consisting of 1,824 full-time teachers, among whom 33 enjoy special government allowances of the State Council in recognition of outstanding achievements in their fields. It also boasts 1 academician of the Chinese Academy of Engineering, 8 distinguished experts of the national Thousand Talents Program, 6 accredited professors and 7 chair professors of Yangtze Scholar Program, 5 granted with funds from the National Outstanding Youth Science Foundation, 1 member of Disciplinary Appraisal Panel of the State Council, 1 member of Academic Degrees Committee of the State Council, 10 winners of the national awards for top teachers, etc. The efforts of the dedicated faculty empower the advancement of the university. At present, HFUT enrolls 29,480 undergraduate students and 11,800 graduate students. It has made remarkable achievements in student education. Throughout the years, key disciplines, courses, textbooks, teaching and experiment centers, teaching staff of HFUT have won numerous awards at all levels, highly reputed in China. It is among the first batch of 61 pilot colleges and universities to conduct the Education and Development Plan for Outstanding Engineers initiated by the Ministry of Education. About 200 projects carried out by HFUT students have been funded by the National University Student Innovation Program. HFUT is dedicated to educating its graduates to become innovative engineering talents with professional proficiency, positive working attitude and entrepreneurship.HFUT sticks to innovation and the integration of teaching, research and production. It has a long-established, application-oriented research culture, and it is keen to support the academics in conducting research that has impact and practical value. It is committed to promoting the development of regional economy by catering to the strategic objectives and needs of the industries, the community and the nation. In 2013, the university has an annual research funding in science of over RMB 447 million. The applications for invention patents total 357, of which 204 are licensed; besides, 82 computer software patents are granted. In recent years, HFUT has won 5 national science-and-technology-related awards, and 19 first prizes at the ministerial or provincial level.HFUT is actively pursuing connections with leading institutions through academic partnerships with top universities worldwide. By supporting a wide range of collaborative activities including faculty and student exchange projects, joint supervision plan and international programs at all levels, HFUT has established academic links with more than 30 prestigious universities around the world, such as Ohio State University in U.S.A. Meanwhile, hundreds of international students from over 30 countries and regions are studying at HFUT.Hefei University of Technology, with its 70-year achievements in several key disciplines, is now striving for even greater success with the ultimate goal of becoming a top innovative university with international prestige and distinctive features. Wikipedia.

Guo X.C.,CAS Center for Space Science and Applied Research | Wang C.,CAS Center for Space Science and Applied Research | Hu Y.Q.,Hefei University of Technology
Journal of Geophysical Research: Space Physics | Year: 2010

The Kelvin-Helmholtz (K-H) instability is found to occur at the low-latitude magnetopause through global magnetohydrodynamic simulations during a period of northward interplanetary magnetic field. The simulation results present the global picture of the nonlinear evolution of the K-H instability at the magnetopause. At the low-latitude boundary layer (within the latitude of about 30°), vortices are generated by the K-H instability at the dayside magnetopause and transported to the far distant magnetotail region along the flank of the magnetosphere; two modes of surface waves propagate along the inner and outer edge of the magnetopause boundary layer, respectively, from the initial point to the tail region; the wavelengths of the inner and outer modes are estimated to vary from 1 to 8 RE as the longitude increases. The vortices are initiated at a longitude of about 28° relative to the Sun-Earth line in the equatorial plane, and their evolution along the magnetopause boundary is studied in detail. We present the characteristics of the inner and outer mode suface waves near the magnetopause boundary layer and find different behaviors of the fast-mode surface waves on the two sides of the magnetopause boundary: the variations of the density and the magnetic field strength of the quasi-fast mode waves are in phase on the magnetosphere side (inner mode), while they are out of phase on the magnetosheath-side (outer mode). The obtained period of the surface waves coincides with the generation period of the vortex at the dayside magnetopause, which is considered to be the intrinsic period of the magetopause for the corresponding interplanetary condition. Copyright 2010 by the American Geophysical Union.

Wang X.-L.,Nanjing University | Wang X.-L.,Hefei University of Technology | Jiang S.-Y.,Nanjing University | Dai B.-Z.,Nanjing University
Precambrian Research | Year: 2010

The Xiong'er Group is an important geologic unit in the southern margin of the North China Craton. It is dominated by the volcanic rocks, dated at 1763±15Ma, that have SiO2 contents ranging from 52.10wt% to 73.51wt%. These volcanic rocks are sub-alkaline and can be classified into three subgroups: basaltic andesites, andesites and rhyolites. They unexceptionally show enrichment of light rare earth elements (LREE) and share similar trace element patterns. Depletions in Nb, Ta, Sr, P and Ti relative to the adjacent elements are evident for all the samples. The volcanic rocks are evolved with low MgO contents (0.29-5.88wt%) and accordingly low Mg# values of 11-53. The Nd isotopes are enriched and show a weak variation with e{open}Nd(t)=-7.12 to -9.63. Zircon Hf isotopes are also enriched with e{open}Hf(t)=-12.02±0.45. The volcanic rocks of the Xiong'er Group are interpreted to represent fractional crystallization of a common mantle source. The volcanic rocks might have been generated by high-degree partial melting of a lithospheric mantle that was originally modified by the oceanic subduction in the Late Archean. This brings a correlation with the subduction-modified lithospheric mantle in an extensional setting during breakup of the Columbia supercontinent in the late Paleoproterozoic, rather than in an arc setting. The elevated SiO2 contents and evolved radiogenic isotope features indicate the possible incorporation into their source of lower crustal materials that have similar Nd isotopic characteristics to the subcontinental lithospheric mantle. The existence of extensive Xiong'er volcanic rocks (60,000km2) indicates an early large-scale subduction-related metasomatism in the area and probably suggest a flat subduction model for the plate-margin magmatism in the Late Archean. © 2010 Elsevier B.V.

Liu W.,Hefei University of Technology
IEEE Photonics Journal | Year: 2015

We propose and investigate the transformation of the surface plasmons (SPs) on the nanometallic cylindrical rod array to tunable light radiation via an exotic Smith-Purcell effect. The electron beam exciting SPs on a single nanometal rod, a pair of rods, and rod array were discussed. The requirements for them to transform into radiation were then explored. The radiation has higher intensity and better coherence than the ordinary Smith-Purcell radiation (SPR). The array of rod pair can get radiation with even higher intensity due to the excitation of gap SP modes. By adjusting the rod diameter or the gap width between the rods, the radiation frequency and intensity can be well tuned. © 2009-2012 IEEE.

Zeng X.,Hefei University of Technology | Ni S.,CAS Wuhan Institute of Geodesy and Geophysics
Geophysical Research Letters | Year: 2010

Very strong signals with apparent velocity higher than Rayleigh wave velocity are observed on noise correlation functions (NCFs) between seismic stations in East Asia. These signals are present on one-month NCFs in ten years period with stable arrival times, indicating their persistent and localized nature. The signals are strong in the frequency band of 0.07-0.12Hz, and their amplitudes show inter-annual but not seasonal variation. Location obtained from two algorithms with GSN and FNET data indicates that the source is situated in Kyushu Island, Japan. After an earthquake is used to account for heterogeneity effects, the location is closer to the Ariake bay but still in the island. The non-seasonal amplitude variation and the peak frequency of 0.1Hz suggest the signals are probably not generated by oceanic sources. This persistent localized microseismic source needs to be taken into consideration in ambient noise tomography studies in East Asia. © 2010 by the American Geophysical Union.

Yang W.-M.,Hefei University of Technology
Nuclear Physics B | Year: 2014

The paper suggests a left-right mirror symmetric model to account for the baryogenesis and asymmetric dark matter. The model can simultaneously accommodate the standard model, neutrino physics, matter-antimatter asymmetry and dark matter. In particular, it naturally and elegantly explains the origin of the baryon and dark matter asymmetries, and clearly gives the close interrelations of them. In addition, the model predicts a number of interesting results, e.g. that the cold dark matter neutrino mass is 3.1 times the proton mass. It is also feasible and promising to test the model in future experiments. © 2014 The Author.

Wu R.,Anhui University | Lu Y.,Anhui University | Chen L.,Hefei University of Technology
Neurocomputing | Year: 2015

In this paper, finite-time stability of a class of fractional delayed neural networks of retarded-type with commensurate order between 0 and 1 is investigated. For such problems in integer-order systems, Lyapunov functions are usually constructed, whereas no specific Lyapunov functions exist in fractional-order cases. By employing inequalities such as Hölder inequality, Gronwall inequalities and inequality scaling skills, some finite-time stability results are derived. For fractional delayed neural models of retarded-type with order 0 < α < 0.5 and 0.5 ≤ α < 1, sufficient conditions for the finite-time stability are presented. Numerical simulations also verify the theoretical results. © 2014 Elsevier B.V.

Shi L.,Hefei University of Technology | Pei C.,Chinese University of Hong Kong | Xu Y.,Chinese University of Hong Kong | Li Q.,Chinese University of Hong Kong
Journal of the American Chemical Society | Year: 2011

Highly ordered quaternary semiconductor Cu2ZnSnS4 nanowires array have been prepared via a facile solvothermal approach using anodic aluminum oxide (AAO) as a hard template. The as-prepared nanowires are uniform and single crystalline. They grow along either the crystalline [110̄] or [111̄] direction. The structure, morphology, composition, and optical absorption properties of the as-prepared Cu2ZnSnS 4 samples were characterized using X-ray powder diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy, and UV-vis spectrometry. A possible formation mechanism of the nanowire arrays is proposed. Governed by similar mechanism, we show that Cu2ZnSnSe4 nanowire array with similar structural characteristics can also be obtained. © 2011 American Chemical Society.

Li F.,Hefei National Laboratory for Physical science at Microscale | Tian Z.,Hefei National Laboratory for Physical science at Microscale | Tian Z.,Hefei University of Technology
Cellular and Molecular Immunology | Year: 2013

Because of its unique blood supply, the liver maintains a special local immune tolerogenic microenvironment. Moreover, the liver can impart this immune tolerogenic effect on other organs, thus inducing systemic immune tolerance. The network of hepatic regulatory cells is an important mechanism underlying liver tolerance. Many types of liver-resident antigen-presenting cells (APCs) have immune regulatory function, and more importantly, they can also induce the differentiation of circulating immune cells into regulatory cells to further extend systemic tolerance. Thus, the liver can be seen as a type of 'school', where liver APCs function as 'teachers' and circulating immune cells function as 'students.'. © 2013 CSI and USTC. All rights reserved.

Ding G.-J.,Hefei University of Technology | Zhou Y.-L.,CAS Institute of High Energy Physics
Chinese Physics C | Year: 2015

We propose to understand the mixing angles and CP-violating phases from the Δ(48) family symmetry combined with the generalized CP symmetry. A model-independent analysis is performed by scanning all the possible symmetry breaking chains. We find a new mixing pattern with only one free parameter, excellent agreement with the observed mixing angles can be achieved and all the CP-violating phases are predicted to take nontrivial values. This mixing pattern is testable in the near future neutrino oscillation and neutrinoless double-beta decay experiments. Finally, a flavor model is constructed to realize this mixing pattern.

Huang B.,Hefei University of Technology
Review of Scientific Instruments | Year: 2015

A number of common issues related to the process of flexible tactile sensor calibration are discussed in this paper, and an estimate of the accuracy of classical calibration methods, as represented by a weight-pulley device, is presented. A flexible tactile sensor calibration method that is based on a six-dimensional force measurement is proposed on the basis of a theoretical analysis. A high-accuracy flexible tactile sensor calibration bench based on the air-bearing six-dimensional force measurement principle was developed to achieve a technically challenging measurement accuracy of 2% full scale (FS) for three-dimensional (3D) flexible tactile sensor calibration. The experimental results demonstrate that the accuracy of the air-bearing six-dimensional force measurement platform can reach 0.2% FS. Thus, the system satisfies the 3D flexible tactile sensor calibration requirement of 2% FS. © 2015 AIP Publishing LLC.

Ren H.,Hefei University of Technology
Physics of Plasmas | Year: 2015

Effects of anisotropy on the geodesic acoustic mode (GAM) are analyzed by using gyro-kinetic equations applicable to low-frequency microinstabilities in a toroidally rotating tokamak plasma. Dispersion relation in the presence of arbitrary Mach number M, anisotropy strength σ, and the temperature ration τ is analytically derived. It is shown that when σ is less than 3 + 2τ, the increased electron temperature with fixed ion parallel temperature increases the normalized GAM frequency. When σ is larger than 3 + 2τ, the increasing of electron temperature decreases the GAM frequency. The anisotropy σ always tends to enlarge the GAM frequency. The Landau damping rate is dramatically decreased by the increasing τ or σ. © 2015 AIP Publishing LLC.

Fan H.,Shanghai JiaoTong University | Fan H.,Hefei University of Technology | Hu L.,Jiangxi Normal University
Frontiers of Physics | Year: 2012

By virtue of the new technique of performing integration over Dirac's ket-bra operators, we explore quantum optical version of classical optical transformations such as optical Fresnel transform, Hankel transform, fractional Fourier transform, Wigner transform, wavelet transform and Fresnel-Hadmard combinatorial transform etc. In this way one may gain benefit for developing classical optics theory from the research in quantum optics, or vice-versa. We cannot only find some new quantum mechanical unitary operators which correspond to the known optical transformations, deriving a new theorem for calculating quantum tomogram of density operators, but also can reveal some new classical optical transformations. For examples, we find the generalized Fresnel operator (GFO) to correspond to the generalized Fresnel transform (GFT) in classical optics. We derive GFO's normal product form and its canonical coherent state representation and find that GFO is the loyal representation of symplectic group multiplication rule. We show that GFT is just the transformation matrix element of GFO in the coordinate representation such that two successive GFTs is still a GFT. The ABCD rule of the Gaussian beam propagation is directly demonstrated in the context of quantum optics. Especially, the introduction of quantum mechanical entangled state representations opens up a new area in finding new classical optical transformations. The complex wavelet transform and the condition of mother wavelet are studied in the context of quantum optics too. Throughout our discussions, the coherent state, the entangled state representation of the two-mode squeezing operators and the technique of integration within an ordered product (IWOP) of operators are fully used. All these have confirmed Dirac's assertion: "... for a quantum dynamic system that has a classical analogue, unitary transformation in the quantum theory is the analogue of contact transformation in the classical theory". © 2012 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Wu Q.,Hefei University of Technology
Journal of the American Society for Information Science and Technology | Year: 2010

Based on the principles of the h-index, I propose a new measure, the w-index, as a particularly simple and more useful way to assess the substantial impact of a researcher's work, especially regarding excellent papers. The w-index can be defined as follows: If w of a researcher's papers have at least 10w citations each and the other papers have fewer than 10(w + 1) citations, that researcher's w-index is w. The results demonstrate that there are noticeable differences between the w-index and the h-index, because the w-index plays close attention to the more widely cited papers. These discrepancies can be measured by comparing the ranks of 20 astrophysicists, a few famous physical scientists, and 16 Price medalists. Furthermore, I put forward the w(q)index to improve the discriminatory power of the w-index and to rank scientists with the same w. The factor q is the least number of citations a researcher with w needed to reach w +1. In terms of both simplicity and accuracy, the w-index or w(q)-index can be widely used for evaluation of scientists, journals, conferences, scientific topics, research institutions, and so on. © 2009 ASIS&T.

Xiong Z.,Hefei University of Technology | Sun X.,Microsoft | Wu F.,Microsoft
IEEE Transactions on Image Processing | Year: 2010

This correspondence presents an image compression approach that integrates our proposed parameter-assistant inpainting (PAI) to exploit visual redundancy in color images. In this scheme, we study different distributions of image regions and represent them with a model class. Based on that, an input image at the encoder side is divided into featured and non-featured regions at block level. The featured blocks fitting the predefined model class are coded by a few parameters, whereas the non-featured blocks are coded traditionally. At the decoder side, the featured regions are restored through PAI relying on both delivered parameters and surrounding information. Experimental results show that our method outperforms JPEG in featured regions by an average bit-rate saving of 76% at similar perceptual quality levels. © 2010 IEEE.

Xiong Z.,Hefei University of Technology | Sun X.,Microsoft | Wu F.,Microsoft
IEEE Transactions on Image Processing | Year: 2010

This paper proposes a robust single-image super-resolution method for enlarging low quality web image/video degraded by downsampling and compression. To simultaneously improve the resolution and perceptual quality of such web image/video, we bring forward a practical solution which combines adaptive regularization and learning-based super-resolution. The contribution of this work is twofold. First, we propose to analyze the image energy change characteristics during the iterative regularization process, i.e., the energy change ratio between primitive (e.g., edges, ridges and corners) and nonprimitive fields. Based on the revealed convergence property of the energy change ratio, appropriate regularization strength can then be determined to well balance compression artifacts removal and primitive components preservation. Second, we verify that this adaptive regularization can steadily and greatly improve the pair matching accuracy in learning-based super-resolution. Consequently, their combination effectively eliminates the quantization noise and meanwhile faithfully compensates the missing high-frequency details, yielding robust super-resolution performance in the compression scenario. Experimental results demonstrate that our solution produces visually pleasing enlargements for various web images/videos. © 2006 IEEE.

Sui Y.,Queen Mary, University of London | Ding H.,Hefei University of Technology | Spelt P.D.M.,Ecole Centrale Lyon | Spelt P.D.M.,University Claude Bernard Lyon 1
Annual Review of Fluid Mechanics | Year: 2014

Computational methods have been extended recently to allow for the presence of moving contact lines in simulated two-phase flows. The predictive capability offered by these methods is potentially large, joining theoretical and experimental methods. Several challenges rather unique to this area need to be overcome, however, notably regarding the conditions near a moving contact line and the very large separation of length scales in these flows. We first summarize the main models for moving contact lines and follow with an overview of computational methods that includes direct continuum approaches and macroscale models that resolve only the large-scale flow by modeling the effects of the conditions near the contact line using theory. Results are presented for contact-line motion on ideal as well as patterned and grooved surfaces and for extensions to account for complexities such as thermocapillarity and phase change. Copyright © 2014 by Annual Reviews. All rights reserved.

Fang S.-E.,Fuzhou University | Ren W.-X.,Hefei University of Technology | Perera R.,Technical University of Madrid
Mechanical Systems and Signal Processing | Year: 2012

Stochastic model updating must be considered for quantifying uncertainties inherently existing in real-world engineering structures. By this means the statistical properties, instead of deterministic values, of structural parameters can be sought indicating the parameter variability. However, the implementation of stochastic model updating is much more complicated than that of deterministic methods particularly in the aspects of theoretical complexity and low computational efficiency. This study attempts to propose a simple and cost-efficient method by decomposing a stochastic updating process into a series of deterministic ones with the aid of response surface models and Monte Carlo simulation. The response surface models are used as surrogates for original FE models in the interest of programming simplification, fast response computation and easy inverse optimization. Monte Carlo simulation is adopted for generating samples from the assumed or measured probability distributions of responses. Each sample corresponds to an individual deterministic inverse process predicting the deterministic values of parameters. Then the parameter means and variances can be statistically estimated based on all the parameter predictions by running all the samples. Meanwhile, the analysis of variance approach is employed for the evaluation of parameter variability significance. The proposed method has been demonstrated firstly on a numerical beam and then a set of nominally identical steel plates tested in the laboratory. It is found that compared with the existing stochastic model updating methods, the proposed method presents similar accuracy while its primary merits consist in its simple implementation and cost efficiency in response computation and inverse optimization. © 2012 Elsevier Ltd.

He W.-Y.,Central South University | Ren W.-X.,Central South University | Ren W.-X.,Hefei University of Technology
Finite Elements in Analysis and Design | Year: 2012

Taking advantages of trigonometric Hermite wavelet that has both good approximation characteristics of trigonometric function and multi-resolution, local characteristics of wavelet as interpolating function, the trigonometric wavelet finite beam element is formulated in the paper to carry out the bending, free vibration and buckling of beam structures. Due to the Hermite interpolation properties of trigonometric wavelet, the proposed trigonometric wavelet finite beam element formulation can deal with the boundary conditions and connection between adjacent elements as the traditional finite element method does. Several numerical examples on the bending, free vibration and buckling analysis of beam structures have demonstrated that the trigonometric wavelet finite element method can achieve a good accuracy with less element adopted, especially for free vibration analysis. © 2011 Elsevier B.V. All rights reserved.

McLoughlin I.V.,Hefei University of Technology
IEEE Transactions on Audio, Speech and Language Processing | Year: 2014

In this paper, reflected sound of frequency just above the audible range is used to detect speech activity. The active signal used is inaudible to humans, readily generated by the typical audio circuitry and components found in mobile telephones, and is robust to background sounds such as nearby voices. In use, the system relies upon a wideband excitation signal emitted from a loudspeaker located near the lips, which reflects from the mouth region and is then captured by a nearby microphone. The state of the lip opening is evaluated periodically by tracking the resonance patterns in the reflected excitation signal. When the lips are open, deep and complex resonances are formed as energy propagates into and then reflects out from the open mouth and vocal tract, with resonance depth being related to the open lip area. When the lips are closed, these resonance patterns are absent. The presence of the resonances can thus serve as a low complexity detection measure. The technique is evaluated for multiple users in terms of sensitivity to source placement and sensor placement. Voice activity detection performance using this measure is further evaluated in the presence of realistic wideband acoustic background noise, as well as artificially added noise. The system is shown to be relatively insensitive to sensor placement, highly insensitive to background noise, and able to achieve greater than 90% voice activity detection accuracy. The technique is even suitable when a subject is whispering in the presence of much louder multi-speaker babble. The technique has potential for speech-based systems operating in high noise environments as well as in silent speech interfaces, whisper-input systems and voice prostheses for speech-impaired users. © 2014 IEEE.

Xu N.,Hefei University of Technology | Xu N.,Chinese University of Hong Kong | Ching E.S.C.,Chinese University of Hong Kong
Soft Matter | Year: 2010

We perform a systematic numerical study of the effects of the particle-size ratio R ≥ 1 on the properties of jammed binary mixtures. We find that changing R does not qualitatively affect the critical scaling of the pressure and coordination number with the compression near the jamming transition, but the critical volume fraction at the jamming transition varies with R. Moreover, the static structure factor (density correlation) S(k) strongly depends on R and shows distinct long wave-length behaviors between large and small particles. Thus the previously reported behavior of S(k) ∼ k in the long wave-length limit is only a special case in the R→1 limit, and cannot be simply generalized to jammed systems with R > 1. © 2010 The Royal Society of Chemistry.

Chen X.,Nanjing University of Aeronautics and Astronautics | Chen X.,China Mobile | Wang X.,Hefei University of Technology | Chen X.,VTT Technical Research Center of Finland
IEEE Wireless Communications Letters | Year: 2013

In this letter, we consider a large-scale multiple-input multiple-output (MIMO) system where the receiver should harvest energy from the transmitter by wireless power transfer to support its wireless information transmission. The energy beamforming in the large-scale MIMO system is utilized to address the challenging problem of long-distance wireless power transfer. Furthermore, considering the limitation of the power in such a system, this letter focuses on the maximization of the energy efficiency of information transmission (bit per Joule) while satisfying the quality-of-service (QoS) requirement, i.e. delay constraint, by jointly optimizing transfer duration and transmit power. By solving the optimization problem, we derive an energy-efficient resource allocation scheme. Numerical results validate the effectiveness of the proposed scheme. © 2012 IEEE.

Cheng Y.,East China Normal University | Zhao L.,Hefei University of Technology | Li T.,China Institute of Atomic Energy
Soft Matter | Year: 2014

In this article, we reviewed the interactions between dendrimers and surfactants with particular focus on the interaction mechanisms and physicochemical properties of the yielding dendrimer-surfactant aggregates. In order to provide insight into the behavior of dendrimers in biological systems, the interactions of dendrimers with bio-surfactants such as phospholipids in bulk solutions, in solid-supported bilayers and at the interface of phases or solid-states were discussed. Applications of the dendrimer-surfactant aggregates as templates to guide the synthesis of nanoparticles and in drug or gene delivery were also mentioned. © 2014 the Partner Organisations.

Gong X.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Li J.,Hefei University of Technology | Xu K.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Wang J.,CAS Suzhou Institute of Nano Technology and Nano Bionics | And 2 more authors.
Journal of the American Chemical Society | Year: 2010

The selective rate of specific ion transport across nanoporous material is critical to biological and nanofluidic systems. Molecular sieves for ions can be achieved by steric and electrical effects. However, the radii of Na+ and K+ are quite similar; they both carry a positive charge, making them difficult to separate. Biological ionic channels contain precisely arranged arrays of amino acids that can efficiently recognize and guide the passage of K+ or Na+ across the cell membrane. However, the design of inorganic channels with novel recognition mechanisms that control the ionic selectivity remains a challenge. We present here a design for a controllable ion-selective nanopore (molecular sieve) based on a single-walled carbon nanotube with specially arranged carbonyl oxygen atoms modified inside the nanopore, which was inspired by the structure of potassium channels in membrane spanning proteins (e.g., KcsA). Our molecular dynamics simulations show that the remarkable selectivity is attributed to the hydration structure of Na + or K+ confined in the nanochannels, which can be precisely tuned by different patterns of the carbonyl oxygen atoms. The results also suggest that a confined environment plays a dominant role in the selectivity process. These studies provide a better understanding of the mechanism of ionic selectivity in the KcsA channel and possible technical applications in nanotechnology and biotechnology, including serving as a laboratory-in-nanotube for special chemical interactions and as a high-efficiency nanodevice for purification or desalination of sea and brackish water. © 2010 American Chemical Society.

Li P.,CAS Institute of Automation | Wang M.,Hefei University of Technology | Cheng J.,CAS Institute of Automation | Xu C.,CAS Institute of Automation | Lu H.,CAS Institute of Automation
IEEE Transactions on Multimedia | Year: 2013

The ability of fast similarity search in a large-scale dataset is of great importance to many multimedia applications. Semantic hashing is a promising way to accelerate similarity search, which designs compact binary codes for a large number of images so that semantically similar images are mapped to close codes. Retrieving similar neighbors is then simply accomplished by retrieving images that have codes within a small Hamming distance of the code of the query. Among various hashing approaches, spectral hashing (SH) has shown promising performance by learning the binary codes with a spectral graph partitioning method. However, the Euclidean distance is usually used to construct the graph Laplacian in SH, which may not reflect the inherent distribution of the data. Therefore, in this paper, we propose a method to directly optimize the graph Laplacian. The learned graph, which can better represent similarity between samples, is then applied to SH for effective binary code learning. Meanwhile, our approach, unlike metric learning, can automatically determine the scale factor during the optimization. Extensive experiments are conducted on publicly available datasets and the comparison results demonstrate the effectiveness of our approach. © 1999-2012 IEEE.

Zhao Y.,Xiamen University | Liang W.,Hefei University of Technology
Chemical Society Reviews | Year: 2012

This tutorial review primarily illustrates rate theories for charge transfer and separation in organic molecules for solar cells. Starting from the Fermi's golden rule for weak electronic coupling, we display the microcanonical and canonical rates, as well as the relationship with the Marcus formula. The fluctuation effect of bridges on the rate is further emphasized. Then, several rate approaches beyond the perturbation limit are revealed. Finally, we discuss the electronic structure theory for calculations of the electronic coupling and reorganization energy that are two key parameters in charge transfer, and show several applications. © 2012 The Royal Society of Chemistry.

Zhang Z.-K.,University of Fribourg | Zhou T.,University of Fribourg | Zhou T.,Hefei University of Technology | Zhang Y.-C.,University of Fribourg
Physica A: Statistical Mechanics and its Applications | Year: 2010

Personalized recommender systems are confronting great challenges of accuracy, diversification and novelty, especially when the data set is sparse and lacks accessorial information, such as user profiles, item attributes and explicit ratings. Collaborative tags contain rich information about personalized preferences and item contents, and are therefore potential to help in providing better recommendations. In this article, we propose a recommendation algorithm based on an integrated diffusion on user-item-tag tripartite graphs. We use three benchmark data sets, Del.icio.us, MovieLens and BibSonomy, to evaluate our algorithm. Experimental results demonstrate that the usage of tag information can significantly improve accuracy, diversification and novelty of recommendations. © 2009 Elsevier B.V. All rights reserved.

Zhuang T.-T.,University of Science and Technology of China | Fan F.-J.,University of Science and Technology of China | Gong M.,Hefei University of Technology | Yu S.-H.,University of Science and Technology of China
Chemical Communications | Year: 2012

Unique Cu 2S-PbS heteronanostructures with good photothermal conversion effect have been synthesized for the first time by a Cu 1.94S nanocrystal seed mediated colloidal solution-phase growth method. The present nanocrystal seed mediated growth method may be extended for the growth of other unique semiconductor heteronanostructures. © The Royal Society of Chemistry 2012.

Ding D.,University of Electronic Science and Technology of China | Wang G.,University of Electronic Science and Technology of China | Wang G.,Hefei University of Technology
IEEE Transactions on Antennas and Propagation | Year: 2013

For antenna design with multiobjective evolutionary algorithm based on decomposition (MOEA/D), population diversity and evolution speed of MOEA/D are two major concerns. Population diversity can be improved by selecting father-individuals along different search directions from external populations sorted by nondominated sorting strategy at small expense of evolution speed. Optimization results of given test instances and a tri-band bow-tie antenna indicate that the modified MOEA/D could generate a large set of alternative solutions in a more efficient way if compared to original MOEA/D. The modified MOEA/D is further demonstrated by designing a quad-band double-sided bow-tie antenna. Both numerical and test results show that modified MOEA/D is a promising multiobjective evolutionary algorithm for antenna design. © 2013 IEEE.

Sheng J.,Hefei University of Technology | Ding Z.,University of Manchester
IET Control Theory and Applications | Year: 2013

This study investigates the consensus control of linear multi-agent systems with communication time delay. Upon exploring certain features of Laplacian matrix, optimal consensus control conditions are identified using semi-discretisation method that develops a mapping of the system response in a finite-dimensional state space. Consensus region and consensus boundary can be obtained by comparing the maximum absolute value of the mapping's eigenvalues with 1. Besides, minimisation of the maximum absolute value of the eigenvalues leads to optimal control gains representing fastest convergence speed. The proposed control only uses relative state information of the system. Numerical simulations validate the proposed control design and show the performance with different control gains and time delays. © The Institution of Engineering and Technology 2013.

Xiong J.,Hefei University of Technology | Petersen I.R.,Australian Defence Force Academy | Lanzon A.,University of Manchester
Automatica | Year: 2012

The paper is concerned with the notion of lossless negative imaginary systems and their stabilization using strictly negative imaginary controllers through positive feedback. Firstly, the concept of lossless negative imaginary transfer functions is introduced and some properties of such transfer functions are studied. Secondly, a Lossless Negative Imaginary Lemma is given which establishes conditions on matrices appearing in a minimal state-space realization that are necessary and sufficient for a transfer function to be lossless negative imaginary. Thirdly, a necessary and sufficient condition is provided for the stabilization of a lossless negative imaginary system by a strictly negative imaginary controller. Finally, a flexible structure example is presented to illustrate the theory. © 2012 Elsevier Ltd. All rights reserved.

Cong H.-P.,Hefei University of Technology | Cong H.-P.,Hefei National Laboratory for Physical science | Qiu J.-H.,Hefei National Laboratory for Physical science | Yu S.-H.,Hefei National Laboratory for Physical science
Small | Year: 2015

Synthetic stimuli-sensitive hydrogel as an important kind of soft intelligent materials has attracted academic and industrial attention as well as its biocompatibility with a high content of water, similar to biological tissues. Under external stimulus, including temperature,[1,2] light[3,4] and pH,[5,6] such hydrogels can exhibit the interesting discontinuous and reversible volume phase transition between a swollen state and a collapsed state, which provide promising potentials in the wide application fi elds of drug release, tissue engineering, sensor, actuator, etc. Among them, the environmentally-thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) hydrogel has been widely investigated,[2,7,8] which shows attractive volume change through absorbing or excluding water attributed from the reversible coil-to-globule transition of macromolecular chains at the well-known lower critical solution temperature (LCST).[9] However, conventional polymer hydrogel with the organic cross-linker often behaves poor mechanical performance and weak resistance to crack propagation because of the lack of an effi cient mechanism for crack energy dissipation, which severely limits its practical applications. Recent work reveals that double-network hydrogel[10,11] with fi rst highlycrosslinked network and second loosely-crosslinked network and nanocomposite hydrogel[12-14] with nano-object as the large cross-linker are the typical models to achieve elastic hydrogel with tough mechanical strength. Very lately, we have reported a kind of polymer/graphene oxide (GO) composite hydrogel with robust and superstretchable mechanical behavior based on a newly-proposed double-network mechanism combined with nanocomposite concept,[15,16] triggered by Ca2+ coordination-induced GO network and covalently crosslinked polymer network which are intertwined by hydrogen bonds between oxygenate groups of GO sheets and the amino groups of polymer chains. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wu X.,Hefei University of Technology | Kroupa P.,University of Bonn
Monthly Notices of the Royal Astronomical Society | Year: 2014

Low-acceleration space-time scale invariant dynamics (SID) predicts two fundamental correlations known from observational galactic dynamics: the baryonic Tully-Fisher relation and a correlation between the observed mass discrepancy and acceleration (MDA) in the low-acceleration regime for disc galaxies. SID corresponds to the deep Modified Newtonian Dynamics limit. The MDA data emerging in cold/warm dark matter (C/WDM) cosmological simulations disagree significantly with the tight MDA correlation of the observed galaxies. Therefore, the most modern simulated disc galaxies, which are delicately selected to have a quiet merging history in a standard dark matter cosmological model, still do not represent the correct rotation curves. Also, the observed tight correlation contradicts the postulated stochastic formation of galaxies in low-mass dark matter haloes. Moreover, we find that SID predicts a baryonic to apparent virial halo (dark matter) mass relation which agrees well with the correlation deduced observationally assuming Newtonian dynamics to be valid, while the baryonic to halo mass relation predicted from CDM models does not. The distribution of the observed ratios of dark matter halo masses to baryonic masses may be empirical evidence for the external field effect, which is predicted in SID as a consequence of the forces acting between two galaxies depending on the position and mass of a third galaxy. Applying the external field effect, we predict the masses of galaxies in the proximity of the dwarf galaxies in the Miller et al. sample. Classical non-relativistic gravitational dynamics is thus best described as being Milgromian, rather than Newtonian. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Ren H.,Hefei University of Technology
Physics of Plasmas | Year: 2015

Geodesic acoustic mode (GAM) in an anisotropic tokamak plasma is investigated in fluid approximation. The collisionless anisotropic plasma is described within the 16-momentum magnetohydrodynamic (MHD) fluid closure model, which takes into account not only the pressure anisotropy but also the anisotropic heat flux. It is shown that the GAM frequency agrees better with the kinetic result than the standard Chew-Goldberger-Low (CGL) MHD model. When zeroing the anisotropy, the 16-momentum result is identical with the kinetic one to the order of 1/q2, while the CGL result agrees with the kinetic result only on the leading order. The discrepancies between the results of the CGL fluid model and the kinetic theory are well removed by considering the heat flux effect in the fluid approximation. © 2015 AIP Publishing LLC.

Wu Z.,Hefei University of Technology | Bouklas N.,University of Texas at Austin | Huang R.,University of Texas at Austin
International Journal of Solids and Structures | Year: 2013

Upon swelling in a solvent, a thin hydrogel layer on a rigid substrate may become unstable, developing various surface patterns. Recent experimental studies have explored the possibilities to generate controllable surface patterns by chemically modifying the molecular structures of the hydrogel near the surface. In this paper, we present a theoretical stability analysis for swelling of hydrogel layers with material properties varying in the thickness direction. As a specialization of the general procedure, hydrogel bilayers with different combinations of the material properties are examined in details. For a soft-on-hard bilayer, the onset of surface instability is determined by the short-wave limit, similar to a homogeneous layer. In contrast, for a hard-on-soft bilayer, a long-wave mode with a finite wavelength emerges as the critical mode at the onset of surface instability, similar to wrinkling of an elastic thin film on a compliant substrate, and the critical swelling ratio is much lower than that for a homogeneous hydrogel layer. A smooth transition of the critical mode is predicted as the volume fraction of the top layer changes, linking surface instability of a homogeneous layer to thin film wrinkling as two limiting cases. The results from the present study suggest that both the critical condition and the instability mode depend sensitively on the variation of the material properties in the thickness direction of the hydrogel layer. © 2012 Elsevier Ltd. All rights reserved.

Fan Y.,Anhui University | Liu L.,City University of Hong Kong | Feng G.,City University of Hong Kong | Song C.,Nanjing University of Science and Technology | Wang Y.,Hefei University of Technology
Automatica | Year: 2013

In this work the connectivity preserving problem of multiple agents with limited communication ranges in the context of rendezvous tasks has been investigated. The communication among agents is considered to be unreliable and the control inputs of agents are required to be bounded. Based on the explicitly defined virtual neighbors, the proximity graph connectivity of the agent group has been preserved. Moreover, by using the constraint function approach, the control inputs are guaranteed to be bounded, which can be easily implemented in practice. It is proved that the proposed control law can not only ensure union connectivity of the underlying communication graph, but also drive the agents to rendezvous. The effectiveness of the control law is illustrated by numerical examples. © 2013 Elsevier Ltd. All rights reserved.

Zhou M.,Zhejiang Normal University | Gao X.,Zhejiang Normal University | Hu Y.,Zhejiang Normal University | Chen J.,Hefei University of Technology | Hu X.,Nanyang Technological University
Applied Catalysis B: Environmental | Year: 2013

Uniform hamburger-like mesoporous carbon-incorporated ZnO (MC-ZnO) nanoarchitectures were facilely prepared by a simple, economical and environmentally benign solvothermal method using ethylene glycol (EG) as solvent in the presence of glucose. The as-obtained samples possessed a high surface area of 104m2g-1 and narrow pore size distribution around 7.2nm. The adsorption behavior of Congo red (CR) onto the products fitted well the Langmuir isotherm and the adsorption process followed the pseudo-second-order kinetic model. The maximum adsorption capacity of CR as 162mgg-1 was achieved by Langmuir equation, while only 18.8mgg-1 was found for by commercial ZnO nanoparticles. Furthermore, the as-prepared nanoarchitectures exhibited enhanced photocatalytic activity for the decolorization of photosensitized dyes (CR and rhodamine-B) under visible-light illumination. Therefore, the MC-ZnO nanoarchitectures developed in this work may be a promising potential material for wastewater treatment. © 2013 Elsevier B.V..

Niu P.,CAS Shenyang Institute of Metal Research | Yin L.-C.,CAS Shenyang Institute of Metal Research | Yang Y.-Q.,CAS Shenyang Institute of Metal Research | Yang Y.-Q.,Hefei University of Technology | And 3 more authors.
Advanced Materials | Year: 2014

There is an inherent driving force to narrow the bandgap of photocatalysts towards this value. Introducing heteroatoms as a general strategy of tuning the bandgap of semiconductors has been attempted to narrow the bandgap of melon in order to extend its light absorption range. Compared to the intensive studies on oxygen vacancies, the underlying role of nitrogen vacancies in modulating optical and photocatalytic properties is rarely considered in developing nitride-based photocatalysts. On the other hand, the spatial distribution of dopants is recognized as an essential issue in modifying the electronic structure of photocatalysts. Homogeneous doping of appropriate heteroatoms throughout a whole particle is indispensable for effective bandgap narrowing, while surface doping can only result in some localized states in the bandgap.

Liu S.,City University of Hong Kong | Liu S.,University of Science and Technology of China | Sun D.,City University of Hong Kong | Zhu C.,Hefei University of Technology
IEEE/ASME Transactions on Mechatronics | Year: 2011

This paper presents a motion-planning approach for coordinating multiple mobile robots in moving along specified paths. The robots are required to fulfill formation requirements while meeting velocity/acceleration constraints and avoiding collisions. Coordination is achieved by planning robot velocities along the paths through a velocity-optimization process. An objective function for minimizing formation errors is established and solved by a linear interactive and general optimizer. Motion planning can be further adjusted online to address emergent demands such as avoiding suddenly appearing obstacles. Simulations and experiments are performed on a group of mobile robots to demonstrate the effectiveness of the proposed coordinated motion planning in multirobot formations. © 2006 IEEE.

Yu J.,Xiamen University | Wang M.,Hefei University of Technology | Tao D.,Intelligent Systems Technology, Inc.
IEEE Transactions on Image Processing | Year: 2012

In image processing, cartoon character classification, retrieval, and synthesis are critical, so that cartoonists can effectively and efficiently make cartoons by reusing existing cartoon data. To successfully achieve these tasks, it is essential to extract visual features that comprehensively represent cartoon characters and to construct an accurate distance metric to precisely measure the dissimilarities between cartoon characters. In this paper, we introduce three visual features, color histogram, shape context, and skeleton, to characterize the color, shape, and action, respectively, of a cartoon character. These three features are complementary to each other, and each feature set is regarded as a single view. However, it is improper to concatenate these three features into a long vector, because they have different physical properties, and simply concatenating them into a high-dimensional feature vector will suffer from the so-called curse of dimensionality. Hence, we propose a semisupervised multiview distance metric learning (SSM-DML). SSM-DML learns the multiview distance metrics from multiple feature sets and from the labels of unlabeled cartoon characters simultaneously, under the umbrella of graph-based semisupervised learning. SSM-DML discovers complementary characteristics of different feature sets through an alternating optimization-based iterative algorithm. Therefore, SSM-DML can simultaneously accomplish cartoon character classification and dissimilarity measurement. On the basis of SSM-DML, we develop a novel system that composes the modules of multiview cartoon character classification, multiview graph-based cartoon synthesis, and multiview retrieval-based cartoon synthesis. Experimental evaluations based on the three modules suggest the effectiveness of SSM-DML in cartoon applications. © 2012 IEEE.

Zhou T.,University of Technology, Sydney | Tao D.,University of Technology, Sydney | Wu X.,Hefei University of Technology
Machine Learning | Year: 2012

Directly applying single-label classification methods to the multi-label learning problems substantially limits both the performance and speed due to the imbalance, dependence and high dimensionality of the given label matrix. Existing methods either ignore these three problems or reduce one with the price of aggravating another. In this paper, we propose a {0, 1} label matrix compression and recovery method termed "compressed labeling (CL)" to simultaneously solve or at least reduce these three problems. CL first compresses the original label matrix to improve balance and independence by preserving the signs of its Gaussian random projections. Afterward, we directly utilize popular binary classification methods (e.g., support vector machines) for each new label. A fast recovery algorithm is developed to recover the original labels from the predicted new labels. In the recovery algorithm, a "labelset distilling method" is designed to extract distilled labelsets (DLs), i.e., the frequently appeared label subsets from the original labels via recursive clustering and subtraction. Given a distilled and an original label vector, we discover that the signs of their random projections have an explicit joint distribution that can be quickly computed from a geometric inference. Based on this observation, the original label vector is exactly determined after performing a series of Kullback-Leibler divergence based hypothesis tests on the distribution about the new labels. CL significantly improves the balanceof the training samples and reduces the dependence between different labels. Moreover, it accelerates the learning process by training fewer binary classifiers for compressed labels, and makes use of label dependence via DLs based tests. Theoretically, we prove the recovery bounds of CL which verifies the effectiveness of CL for label compression and multi-label classification performance improvement brought by label correlations preserved in DLs.We show the effectiveness, efficiency and robustness of CL via 5 groups of experiments on 21 datasets from text classification, image annotation, scene classification, music categorization, genomics and web page classification. © The Author(s) 2012.

Day J.M.D.,University of California at San Diego | Day J.M.D.,University of Maryland University College | Walker R.J.,University of Maryland University College | Qin L.,Carnegie Institution of Washington | And 2 more authors.
Nature Geoscience | Year: 2012

Core formation should strip highly siderophile elements (HSEs) from planetary mantles according to the expected metalg-silicate partition coefficients. However, studies of Earth, the Moon and Mars indicate mantles with HSE abundances in chondrite-relative proportions that exceed the values expected from metalg-silicate partitioning. Competing hypotheses have been proposed to account for these observations, including metalg-silicate partitioning at higher pressures and temperatures and late accretion. Here we present petrological and geochemical analyses of diogenite meteorites that represent mantle and crustal materials from two or more differentiated asteroids. We find that diogenites show HSE abundances that are consistent with metalg-silicate equilibration, followed by minor continued accretion. Isotope chronometry supports diogenite crystallization ages within 2-3 million years of Solar System formation, indicating that late accretion occurred earlier than postulated for Earth, the Moon and Mars. The early timing and occurrence on differentiated asteroids, as well as on the larger terrestrial planets, therefore ties late accretion to planetary growth. On asteroidal bodies, such as the diogenite parent bodies, variations in HSE compositions may reflect regional rather than global effects. In contrast, for Earth, the Moon and Mars, compositional variations in mantle materials seem to be consistent with more homogeneous distributions through prolonged melting and/or solid-state convection. © 2012 Macmillan Publishers Limited. All rights reserved.

Yang X.,Hefei University of Technology | Clausi D.A.,University of Waterloo
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2012

This paper presents a new approach to sea ice segmentation in synthetic aperture radar (SAR) intensity images by combining an edge-preserving region (EPR)-based representation with region-level MRF models. To construct the EPR-based representation of a SAR image, edge strength is measured using instantaneous coefficient of variation (ICOV) upon which the watershed algorithm is applied to partition the image into primitive regions. In addition, two new metrics for quantitative assessment of region characteristics (region accuracy and region redundancy) are defined and used for parameter estimation in the ICOV extraction process towards desired region characteristics. In combination with a region-level MRF, the EPR-based representation facilitates the segmentation process by largely reducing the search space of optimization process and improving parameter estimation of feature model, leading to considerable computational savings and less probability of false segmentation. The proposed segmentation method has been evaluated using a synthetic sea ice image corrupted with varying levels of speckle noise as well as real SAR sea ice images. Relative to the existing region-level MRF-based methods, testing results have demonstrated that our proposed method substantially improves the segmentation accuracy at high speckle noise and achieves on average 29% reduction of computational time. © 2008-2012 IEEE.

Xiang G.Y.,Griffith University | Xiang G.Y.,Hefei University of Technology | Higgins B.L.,Griffith University | Berry D.W.,University of Waterloo | And 2 more authors.
Nature Photonics | Year: 2011

Precise interferometric measurement is vital to many scientific and technological applications. Using quantum entanglement allows interferometric sensitivity that surpasses the shot-noise limit (SNL). To date, experiments demonstrating entanglement-enhanced sub-SNL interferometry, and most theoretical treatments, have addressed the goal of increasing signal-to-noise ratios. This is suitable for phase-sensing - detecting small variations about an already known phase. However, it is not sufficient for ab initio phase-estimation - making a self-contained determination of a phase that is initially completely unknown within the interval [0, 2π). Both tasks are important, but not equivalent. To move from the sensing regime to the ab initio estimation regime requires a non-trivial phase-estimation algorithm. Here, we implement a 'bottom-up' approach, optimally utilizing the available entangled photon states, obtained by post-selection. This enables us to demonstrate sub-SNL ab initio estimation of an unknown phase by entanglement-enhanced optical interferometry. © 2011 Macmillan Publishers Limited. All rights reserved.

Liao C.,Hefei University of Technology
Current topics in medicinal chemistry | Year: 2016

Metalloproteins have attracted momentous attentions for the treatment of many human diseases, including cancer, HIV, hypertension, etc. This article reviews the progresses that have been made in the field of drug development of metalloprotein inhibitors, putting emphasis on the targets of carbonic anhydrase, histone deacetylase, angiotensin converting enzyme, and HIV-1 integrase. Many other important metalloproteins are also briefly discussed. The binding and coordination modes of different marketed metalloprotein inhibitors are stated, providing insights to design novel metal binding groups and further novel inhibitors for metalloproteins.

Qu X.-F.,Chinese Academy of Sciences | Zhou G.-T.,Chinese Academy of Sciences | Fu S.-Q.,Hefei University of Technology
Journal of Physical Chemistry C | Year: 2010

Hefei National Laboratory for Physical Sciences at Microscale.A biomolecule-assisted hydrothermal route to the fabrication of magnetite (Fe 3O4) with uniform microsized and regular octahedral morphology has been successfully developed by use of toxic-free aspartic acid as reducing reagent and FeCl3 • 6H2O as iron source. The as-prepared magnetite was characterized by X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), and highresolution transmission electron microscopy (HRTEM). Altering different experimental parameters showed that pH of the aspartic acid solution, concentration of aspartic acid, and hydrothermal temperature can significantly influence product phase composition. Furthermore, a series of time-course experiments revealed that growth of regular octahedral magnetite is controlled by the Ostwald ripening process. This biomoleculeassisted route may be expected to be applicable for the fabrication of other transition metal oxides with uniform size and morphology. Besides, magnetic properties of the product were characterized on a vibrating sample magnetometer (VSM). The values of saturation magnetization (Ms), remanent magnetization (Mr), and coercivity (Hc) of the magnetite octahedrons are 71.6 emu/g, 9.8 emu/g, and 120 Oe, respectively. The electrochemical performances of the magnetite octahedra exhibit a discharge capacity of ca. 600 mAh/g in the first cycle and a discharge voltage of 0.92 and 0.74 V, respectively. © 2010 American Chemical Society.

Hermann J.,Australian National University | Zheng Y.-F.,Hefei University of Technology | Rubatto D.,Australian National University
Elements | Year: 2013

Observations from ultrahigh-pressure metamorphic rocks combined with experimentally determined phase relations provide a framework for understanding fluid-mediated mass transfer in deeply subducted continental crust. At temperatures below 650 °C, aqueous fluids derived from dehydration reactions involving hydrous phases contain limited amounts of solutes. At temperatures of 700-800 °C, a supercritical fluid with a composition intermediate between aqueous fluid and hydrous melt might be present. The most significant mass transfer at ultrahigh-pressure conditions occurs at 800-1000 °C, where subducted crust undergoes partial melting related to the breakdown of the hydrous mineral phengite. Partial melting leads to a significant change in the composition and density of the rocks, and also affects the rheology of deeply subducted crust.

Gan M.,Hefei University of Technology | Gan M.,Central South University | Peng H.,Central South University | Chen L.,Central South University
Information Sciences | Year: 2012

We present a hybrid global-local optimization algorithm for parameter estimation of radial basis function (RBF) networks and the RBF-type autoregressive models without exogenous inputs (RBF-AR) or with exogenous inputs (RBF-ARX). The RBF-AR (X) models are quasi-linear time-varying AR (X) models with Gaussian RBF network-style coefficients, which have been used to effectively model the nonlinear behavior of various complex systems. However, the identification of these models is a difficult optimization problem because of the large number of local minima. A hybrid approach is proposed in this paper to achieve better optimization results for these RBF-type models. The applied hybrid search strategy (EA-SNPOM) is developed by combining an evolutionary algorithm (EA) with a gradient-based algorithm known as the structured nonlinear parameter optimization method (SNPOM). This strategy makes use of the robustness of the EA to cover an entire global search space and the efficiency of the gradient search to converge to a local optimum. Several examples of time series modeling and system identification are presented. The simulation results indicate that the performance of the proposed hybrid approach is better than the performance obtained from using each method (EA or SNPOM) alone. Furthermore, the RBF-AR (X) models estimated by the EA-SNPOM achieve much better modeling accuracy relative to other neural networks or fuzzy models in the simulations. © 2012 Elsevier Inc. All rights reserved.

Zhang S.B.,Hefei University of Technology | Wang J.G.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Janev R.K.,Macedonian Academy of science and Arts
Physical Review Letters | Year: 2010

The effects of Coulomb interaction screening on electron-hydrogen atom excitation in the n=2 threshold region are investigated by using the R-matrix method with pseudostates. The interaction screening lifts the l degeneracy of n=2 Coulomb energy level, producing two distinct thresholds for 2s and 2p states. The phenomenon of transformation of P1,3 and D1 Feshbach resonances into shape-type resonances is observed when they pass across the 2s and 2p threshold, respectively, as the interaction screening increases. It is shown that this resonance transformation leads to dramatic effects in the 1s→2s and 1s→2p excitation collision strengths in the n=2 threshold collision energy region. © 2010 The American Physical Society.

Liu R.,Hefei University of Technology
Monthly Notices of the Royal Astronomical Society | Year: 2013

We report in this paper a solar eruptive event, in which a vertical current sheet (VCS) is observed in the wake of an erupting flux rope in the Solar Dynamic Observatory (SDO)/Atmospheric Imaging Assembly (AIA) 131Å passband. The VCS is first detected following the impulsive acceleration of the erupting flux rope but prior to the onset of a non-thermal hard X-ray (HXR)/microwave burst, with plasma blobs moving upwards at speeds up to 1400 km s-1 along the sheet. The timing suggests that the VCS with plasma blobs might not be the primary accelerator for non-thermal electrons emitting HXRs/microwaves. The initial, slow acceleration of the erupting structure is associated with the slow elevation of a thermal looptop HXR source and the subsequent, impulsive acceleration is associated with the downward motion of the looptop source. We find that the plasma blobs moving downwards within the VCS into the cusp region and the flare loops retracting from the cusp region make a continuous process, with the former apparently initiating the latter, which provides a 3D perspective on reconnections at the VCS. We also identify a dark void moving within the VCS towards the flare arcade, which suggests that dark voids in supra-arcade downflows are of the same origin as plasma blobs within the VCS. ©2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

Xu J.,City University of Hong Kong | Xu J.,Hefei University of Technology | Chen Z.,City University of Hong Kong | Zapien J.A.,City University of Hong Kong | And 2 more authors.
Advanced Materials | Year: 2014

Semiconductor-sensitized solar cells (SSCs) are emerging as promising devices for achieving efficient and low-cost solar-energy conversion. The recent progress in the development of ZnO-nanostructure-based SSCs is reviewed here, and the key issues for their efficiency improvement, such as enhancing light harvesting and increasing carrier generation, separation, and collection, are highlighted from aspects of surface-engineering techniques. The impact of other factors such as electrolyte and counter electrodes on the photovoltaic performance is also addressed. The current challenges and perspectives for the further advance of ZnO-based SSCs are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang Y.-H.P.,Virginia Polytechnic Institute and State University | Zhang Y.-H.P.,Gate Fuels Inc. | Huang W.-D.,Virginia Polytechnic Institute and State University | Huang W.-D.,Hefei University of Technology
Trends in Biotechnology | Year: 2012

In this opinion, we suggest the electricity-carbohydrate-hydrogen (ECHo) cycle which bridges primary energies and secondary energies. Carbohydrates are sources of food, feed, liquid biofuels, and renewable materials and are a high-density hydrogen carrier and electricity storage compounds (e.g. >3000 Wh/kg). One element of this ECHo cycle can be converted to another reversibly and efficiently depending on resource availability, needs and costs. This cycle not only supplements current and future primary energy utilization systems for facilitating electricity and hydrogen storage and enhancing secondary energy conversion efficiencies, but also addresses such sustainability challenges as transportation fuel production, CO 2 utilization, fresh water conservation, and maintenance of a small closed ecosystem in emergency situations. © 2012 Elsevier Ltd.

Tan P.,Chinese University of Hong Kong | Xu N.,Hefei University of Technology | Xu L.,Chinese University of Hong Kong
Nature Physics | Year: 2013

When a system undergoes a transition from a liquid to a solid phase, it passes through multiple intermediate structures before reaching the final state. However, our knowledge on the exact pathways of this process is limited, mainly owing to the difficulty of realizing direct observations. Here, we experimentally study the evolution of symmetry and density for various colloidal systems during liquid-to-solid phase transitions, and visualize kinetic pathways with single-particle resolution. We observe the formation of relatively ordered precursor structures with different symmetries, which then convert into metastable solids. During this conversion, two major cross-symmetry pathways always occur, regardless of the final state and the interaction potential. In addition, we find a broad decoupling of density variation and symmetry development, and discover that nucleation rarely starts from the densest regions. These findings hold for all of our samples, suggesting the possibility of finding a unified picture for the complex crystallization kinetics in colloidal systems. © 2014 Macmillan Publishers Limited. All rights reserved.

Huang Y.B.,Hefei University of Technology
Yi chuan = Hereditas / Zhongguo yi chuan xue hui bian ji | Year: 2012

As a means of visual function testing and visual related mutants screening, the optokinetic response (OKR) and the optomotor response (OMR) behaviour tests are simple and effective tools for visual functional testing, which have been widely used in studying zebrafish larvae. However, adult zebrafish OKR analysis method is rarely reported. In this study, the methods of inducing adult zebrafish OKR behaviour, as well as tracking the movement of eyes using Pattern Match approaches, are presented. The quantitative measurement of the adult zebrafish OKR behaviour was successfully established. Using these methods, the binocular vision area was found to make a certain contribution to OKR behaviour. Moreover, the monocular vision of adult zebrafish showed a certain degree of directional sensitivity to moving gratings. Such approaches can also be applied to the zebrafish larvae OKR. The abnormal OKR behaviour phenomenon of period1b mutant larvae fish was detected.

Fu C.,Hefei University of Technology | Yang S.-L.,Key Laboratory of Process Optimization and Intelligent Decision making
Expert Systems with Applications | Year: 2011

To combine interval-valued belief structures (IBSs), it is necessary to investigate the applicability of Dempsters rule to know whether Dempsters rule is adequate to be used and whether other alternatives are needed. This makes it significant to investigate IBSs pairwise relationships (IPRs) since they have an important impact on the applicability of Dempsters rule to the combination of two IBSs. IPRs can be constructed based on beliefs pairwise relationships (BPRs), so this paper proposes a consistency measure to quantitatively divide BPRs into three categories. Using a consistency interval between two IBSs that is obtained by solving a pair of optimization problems constructed based on the consistency measure, IPRs are quantified and divided into six categories on the basis of BPRs. According to IPRs, the applicability of Dempsters rule to the combination of two IBSs is recommended. Finally, the applicability of Dempsters rule to the combination of multiple IBSs is investigated. © 2010 Elsevier Ltd. All rights reserved.

Ke F.,Anhui University | Qiu L.-G.,Anhui University | Yuan Y.-P.,Anhui University | Jiang X.,Anhui University | Zhu J.-F.,Hefei University of Technology
Journal of Materials Chemistry | Year: 2012

A novel kind of porous microsphere with a magnetic core and a tunable metal-organic framework (MOF) shell has been successfully fabricated utilizing a versatile step-by-step assembly strategy. The structure, composition, and function of the microspheres can be judiciously tailored by choosing various metal ions and polyfunctional organic ligands or tuning the assembly processes. Our results provide a valuable methodology for rationally designing novel core-shell architectures and MOF-based porous magnetic platforms. © 2012 The Royal Society of Chemistry.

Cong H.-P.,Anhui University of Science and Technology | Cong H.-P.,Hefei University of Technology | Wang P.,Anhui University of Science and Technology | Yu S.-H.,Anhui University of Science and Technology
Chemistry of Materials | Year: 2013

Superior mechanical properties and self-healing are two hot topics in hydrogel science due to their tight relationship with the following potential application scopes. Most of the conventional hydrogels do not possess both features at the same time. Herein, we expand the recently proposed intertwined double-network mechanism and prepare a novel class of graphene oxide (GO)/poly(acryloyl-6-aminocaproic acid) (PAACA) composite hydrogels with enhanced mechanical properties and self-healing capability to pH stimulus. Without the use of any conventional organic cross-linkers, the double networks in GO/PAACA hydrogels are triggered by GO nanosheets and calcium ions as cross-linkers. For one thing, Ca2+ induces the formation of the 3D cross-linked network through coordination interactions with both oxygen-containing groups of GO nanosheets and polar groups of PAACA side chains. For another, powerful hydrogen-bonding network is simultaneously interconnected, attributed to the interactions of polar groups of PAACA side chains with both other polar groups of PAACA side chains and oxygen-containing groups of GO nanosheets. © 2013 American Chemical Society.

Shu Q.,Hefei University of Technology
Journal of University of Science and Technology of China | Year: 2012

As a result of having an extremely strong uncertainty and uniqueness in generation and scenario evolvement for unconventional emergency, the traditional decision-making paradigm of "forecast-response" should be replaced by the "scenario- response" paradigm for real-time decision making. Here, based on a analysis of the content and internal factors of unconventional emergency, the process of scenario and its evolvement were described for emergency decision-making. On the basis of an in-depth analysis "scenes-response" paradigm and decision-making rules, the generation process of emergency decision-making alternatives was given.

Zhang H.-F.,Anhui University | Yang Z.,University of Electronic Science and Technology of China | Wu Z.-X.,Lanzhou University | Wang B.-H.,Hefei University of Technology | Zhou T.,University of Electronic Science and Technology of China
Scientific Reports | Year: 2013

Facing the threats of infectious diseases, we take various actions to protect ourselves, but few studies considered an evolving system with competing strategies. In view of that, we propose an evolutionary epidemic model coupled with human behaviors, where individuals have three strategies: vaccination, self-protection and laissez faire, and could adjust their strategies according to their neighbors' strategies and payoffs at the beginning of each new season of epidemic spreading. We found a counter-intuitive phenomenon analogous to the well-known Braess's Paradox, namely a better condition may lead to worse performance. Specifically speaking, increasing the successful rate of self-protection does not necessarily reduce the epidemic size or improve the system payoff. The range and degree of the Braess's Paradox are sensitive to both the parameters characterizing the epidemic spreading and the strategy payoff, while the existence of the Braess's Paradox is insensitive to the network topologies. This phenomenon can be well explained by a mean-field approximation. Our study demonstrates an important fact that a better condition for individuals may yield a worse outcome for the society.

Ling Z.-H.,Hefei University of Technology | Richmond K.,University of Edinburgh | Yamagishi J.,University of Edinburgh
IEEE Transactions on Audio, Speech and Language Processing | Year: 2013

In previous work we proposed a method to control the characteristics of synthetic speech flexibly by integrating articulatory features into a hidden Markov model (HMM) based parametric speech synthesizer. In this method, a unified acoustic-articulatory model is trained, and context-dependent linear transforms are used to model the dependency between the two feature streams. In this paper, we go significantly further and propose a feature-space-switched multiple regression HMM to improve the performance of articulatory control. A multiple regression HMM (MRHMM) is adopted to model the distribution of acoustic features, with articulatory features used as exogenous explanatory variables. A separate Gaussian mixture model (GMM) is introduced to model the articulatory space, and articulatory-to-acoustic regression matrices are trained for each component of this GMM, instead of for the context-dependent states in the HMM. Furthermore, we propose a task-specific context feature tailoring method to ensure compatibility between state context features and articulatory features that are manipulated at synthesis time. The proposed method is evaluated on two tasks, using a speech database with acoustic waveforms and articulatory movements recorded in parallel by electromagnetic articulography (EMA). In a vowel identity modification task, the new method achieves better performance when reconstructing target vowels by varying articulatory inputs than our previous approach. A second vowel creation task shows our new method is highly effective at producing a new vowel from appropriate articulatory representations which, even though no acoustic samples for this vowel are present in the training data, is shown to sound highly natural. © 2012 IEEE.

Idris N.M.,National University of Singapore | Jayakumar M.K.G.,National University of Singapore | Bansal A.,National University of Singapore | Zhang Y.,National University of Singapore | Zhang Y.,Hefei University of Technology
Chemical Society Reviews | Year: 2015

Remote activation of photoactivable therapeutic compounds by light provides a high spatial and temporal control for activating the therapeutic agent. However, photoactivable compounds are mostly responsive towards ultraviolet (UV) or visible light radiation that has poor tissue penetration depth besides being unsafe to the body in the case of UV light. Nanoparticles with energy upconversion hold potential in overcoming this limit by using safe and deeply penetrating near-infrared (NIR) light. These upconversion nanoparticles (UCNs) act as versatile nanotransducers as they convert NIR light to light of shorter wavelengths that can be tuned to the NIR, visible or UV colors to suit different activation wavelengths. Their highly unusual optical properties to fluoresce with near-zero photobleaching, photoblinking and background autofluorescence are unique and an added benefit when used simultaneously as optional imaging agents. This article reviews recent advancements in the use of UCNs for photoactivation of therapeutic agents. Specifically, we discuss the use of these UCNs for activation of light-sensitive/photocaged molecules or photosensitizers for photocontrolled-delivery and photodynamic therapy. This journal is © The Royal Society of Chemistry.

Yang W.-M.,Hefei University of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

I suggest a practical particle model as an extension to the standard model. The model has a TeV scale U(1)B-L symmetry and it contains the fourth generation fermions with the TeV scale masses, including a cold dark matter neutrino. The model can completely account for the fermion flavor puzzles, the cold dark matter, and the matter-antimatter asymmetry through the leptogenesis. In particular, it is quite feasible and promising to test the model in future experiments. © 2013 American Physical Society.

Li C.-Z.,University of Washington | Chang C.-Y.,University of Washington | Zang Y.,University of Washington | Ju H.-X.,University of Washington | And 6 more authors.
Advanced Materials | Year: 2014

Conductive fullerene electron-transporting layers (ETLs) are developed to facilitate the solution processing of highly efficient inverted OSCs with power conversion efficiency (PCE) reaching 9.6%. Its high conductivity also allows devices to be fabricated independently of the ETL thickness (up to ca. 50 nm). Transient photovoltage (TPV) measurements are used to shed light on how these conductive ETLs help suppress charge recombination in solar cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fan Y.,CAS Institute of Policy and Management | Xu J.-H.,CAS Institute of Policy and Management | Xu J.-H.,Hefei University of Technology
Energy Economics | Year: 2011

This paper characterizes weekly international oil price fundamentals since 2000 by analyzing the transformation of the market mechanism based on structural change perspective. Using endogenously-determined break tests that allow for changes in both level and trend, we divide the price fluctuations in the international oil market after 2000 into three stages: "Relatively calm market" period (January 07, 2000, to March 12, 2004); the "Bubble accumulation" period (March 19, 2004, to June 06, 2008,); and the "Global economic crisis" period (June 13, 2008, to September 11, 2009). The results show the existence of structural breaks refutes the utility of investigation of the full sample period as a whole. And in different structural periods the main drivers of oil price changes and their way of influence and degree are significantly distinct. Then we demonstrate the evolving process of market mechanism since 2000. Through establishing comparative models, we also quantitatively measure the roles of speculation and episodic events in oil price fluctuations. © 2011 Elsevier B.V.

Xuan X.,Hefei University of Technology
Indoor and Built Environment | Year: 2016

A combination of quantitative and qualitative approaches was used to evaluate the effectiveness of LEED-certified healthcare settings from the perspectives of both staff and facility managers. This study surveyed 164 staff members in two healthcare settings in a case study to compare LEED and non-LEED-certified healthcare facilities and surveyed 146 staff in six LEED-certified healthcare settings for the main study. Telephone interviews with six facility managers were used to verify the survey results and further examine the facilities' performance and the effectiveness of the LEED strategies. An independent t-test was used to examine the difference between a LEED hospital and a non-LEED hospital in one healthcare system. Building performance was rated higher by staff in the LEED-certified hospital than in the non-LEED hospital. Multivariate analysis of variance (MANOVA) was conducted to compare staff ratings between the silver and gold LEED certification levels and between males and females, as well as to explore the possibility of interaction effects. Compared with the staff in silver-certified facilities, staff members in the gold-certified hospitals gave the buildings significantly higher ratings in most performance variables, including building overall, overall comfort and controllability. Males felt more comfortable than females with temperatures in healthcare facilities. © International Society of the Built Environment.

Jiang G.,Hefei University of Technology | Jiang G.,University of Victoria | Pichaandi J.,University of Victoria | Johnson N.J.J.,University of Victoria | And 2 more authors.
Langmuir | Year: 2012

Ligands on the nanoparticle surface provide steric stabilization, resulting in good dispersion stability. However, because of their highly dynamic nature, they can be replaced irreversibly in buffers and biological medium, leading to poor colloidal stability. To overcome this, we report a simple and effective cross-linking methodology to transfer oleate-stabilized upconverting NaYF 4 core/shell nanoparticles (UCNPs) from hydrophobic to aqueous phase, with long-term dispersion stability in buffers and biological medium. Amphiphilic poly(maleic anhydride-alt-1-octadecene) (PMAO) modified with and without poly(ethylene glycol) (PEG) was used to intercalate with the surface oleates, enabling the transfer of the UCNPs to water. The PMAO units on the phase transferred UCNPs were then successfully cross-linked using bis(hexamethylene)triamine (BHMT). The primary advantage of cross-linking of PMAO by BHMT is that it improves the stability of the UCNPs in water, physiological saline buffers, and biological growth media and in a wide range of pH values when compared to un-cross-linked PMAO. The cross-linked PMAO-BHMT coated UCNPs were found to be stable in water for more than 2 months and in physiological saline buffers for weeks, substantiating the effectiveness of cross-linking in providing high dispersion stability. The PMAO-BHMT cross-linked UCNPs were extensively characterized using various techniques providing supporting evidence for the cross-linking process. These UCNPs were found to be stable in serum supplemented growth medium (37 °C) for more than 2 days. Utilizing this, we demonstrate the uptake of cross-linked UCNPs by LNCaP cells (human prostate cancer cell line), showing their utility as biolabels. © 2012 American Chemical Society.

Xie L.,Intelligent Systems Technology, Inc. | Tian Q.,University of Texas at San Antonio | Wang M.,Hefei University of Technology | Zhang B.,Intelligent Systems Technology, Inc.
IEEE Transactions on Image Processing | Year: 2014

In image classification tasks, one of the most successful algorithms is the bag-of-features (BoFs) model. Although the BoF model has many advantages, such as simplicity, generality, and scalability, it still suffers from several drawbacks, including the limited semantic description of local descriptors, lack of robust structures upon single visual words, and missing of efficient spatial weighting. To overcome these shortcomings, various techniques have been proposed, such as extracting multiple descriptors, spatial context modeling, and interest region detection. Though they have been proven to improve the BoF model to some extent, there still lacks a coherent scheme to integrate each individual module together. To address the problems above, we propose a novel framework with spatial pooling of complementary features. Our model expands the traditional BoF model on three aspects. First, we propose a new scheme for combining texture and edge-based local features together at the descriptor extraction level. Next, we build geometric visual phrases to model spatial context upon complementary features for midlevel image representation. Finally, based on a smoothed edgemap, a simple and effective spatial weighting scheme is performed to capture the image saliency. We test the proposed framework on several benchmark data sets for image classification. The extensive results show the superior performance of our algorithm over the state-of-the-art methods. © 2014 IEEE.

Jia Q.,Hefei University of Technology
IEEE Journal of Quantum Electronics | Year: 2013

Using an approach unlike that in the literature, the effects induced by waveguides on the gain in infrared free-electron lasers are analyzed for both the low and the high gain regimes. By analyzing the relation of the detuning parameter to the radiation frequency and the waveguide parameter, the radiation frequency and the slippage are analyzed not merely for the resonance case, but for more general cases. Their dependence on the waveguide parameter is analytically presented for an arbitrary value of the detuning, the features of the gain and the requirements for the waveguide parameter can be easily revealed. It is found that the derivative of the detuning parameter with respect to the radiation wavenumber is proportional to the slippage. The analysis shows that the zero slippage always exists, and to have gain at the zero-slippage frequency corresponds to obtaining a gain curve with a single broadband peak. This can be realized for both the high gain and the low gain regions by choosing the appropriate dimension of the waveguide. It is also shown that the higher order modes of the waveguide have greater effect on the high gain than on the low gain regime. © 1965-2012 IEEE.

Chen Y.-L.,Peking University | Zou C.-L.,Hefei University of Technology | Hu Y.-W.,Peking University | Gong Q.,Peking University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

This paper investigates the confinement and quality (Q) factors of the dielectric mode, exterior surface plasmonic mode, and interior surface plasmonic mode in a metal-nanolayer-coated silica microtoroid. It is found that the confinement of these modes relies mainly on the real part of the coating-metal permittivity, and a smaller negative real part produces a lower effective potential barrier which plays distinct roles in these three types of modes. For the exterior plasmonic mode, a lower potential leads to a better confinement and thus lower radiation losses, while for the interior plasmonic mode and the dielectric mode, a higher potential can play a very positive role in suppressing the radiation losses. The metal absorption loss, as expected, is directly related to the imaginary part of the metal permittivity and the energy fraction of the mode in the metal layer, and the latter depends on the confinement or, namely, the effective potential barrier induced by the metal nanolayer. We also compare the plasmonic modes in the coated microcavity and the dielectric modes in the uncoated microcavity at different cavity sizes. An interesting finding is that when the cavity is small enough, which is highly desirable for compact photonic devices, the Q factors of the plasmonic modes even exceed significantly that of the uncoated dielectric modes. © 2013 American Physical Society.

Hu B.,Hefei University of Technology | Hu B.,Tongji University
Engineering Structures | Year: 2013

This paper presents the assessment results of existing criteria for sufficiently/insufficiently fiber-reinforced polymer (FRP)-confined concrete, develops a unified ultimate axial stress model and proposes an improved criterion. The existing criteria for FRP-confined concrete in circular and rectangular columns are reviewed. A large database has been established by collecting the available experimental results from the open literature for evaluation of the existing criteria. The assessment results indicate that there is still room for improvement in the existing criteria, especially in those for rectangular specimens. An improved criterion for FRP-confined concrete in both circular and rectangular columns is proposed on the basis of the existing criteria and deduced from the unified ultimate axial stress model which is developed in this paper as well. Comparisons between the criterion predictions and the test results demonstrate the accuracy of the proposed criterion. © 2012 Elsevier Ltd.

Xue P.,Nanjing Southeast University | Qin H.,Nanjing Southeast University | Tang B.,Nanjing Southeast University | Sanders B.C.,Hefei University of Technology | Sanders B.C.,University of Calgary
New Journal of Physics | Year: 2014

We realize the quasi-periodic dynamics of a quantum walker over 2.5 quasi-periods by realizing the walker as a single photon passing through a quantum-walk optical-interferometer network. We introduce fully controllable polarization-independent phase shifters in each optical path to realize arbitrary site-dependent phase shifts, and employ large clear-aperture beam displacers, while maintaining high-visibility interference, to enable 10 quantum-walk steps to be reached. By varying the half-wave-plate setting, we control the quantum-coin bias thereby observing a transition from quasi-periodic dynamics to ballistic diffusion. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Kocsis S.,Center for Quantum Computation and Communication Technology | Kocsis S.,Griffith University | Xiang G.Y.,Griffith University | Xiang G.Y.,Hefei University of Technology | And 4 more authors.
Nature Physics | Year: 2013

Photons are the best long-range carriers of quantum information, but the unavoidable absorption and scattering in a transmission channel places a serious limitation on viable communication distances. Signal amplification will therefore be an essential feature of quantum technologies, with direct applications to quantum communication, metrology and fundamental tests of quantum theory. Non-deterministic noiseless amplification of a single mode can circumvent the challenges related to amplifying a quantum signal, such as the no-cloning theorem and the minimum noise cost for deterministic quantum state amplification. However, existing devices are not suitable for amplifying the fundamental optical quantum information carrier: a qubit coherently encoded across two optical modes. Here, we construct a coherent two-mode amplifier to demonstrate the first heralded noiseless linear amplification of a qubit encoded in the polarization state of a single photon. In doing so, we increase the transmission fidelity of a realistic qubit channel by up to a factor of five. Qubit amplifiers promise to extend the range of secure quantum communication and other quantum information science and technology protocols. © 2013 Macmillan Publishers Limited.

Cong H.-P.,Suzhou University of Science and Technology | Cong H.-P.,Hefei University of Technology | Chen J.-F.,Suzhou University of Science and Technology | Yu S.-H.,Suzhou University of Science and Technology
Chemical Society Reviews | Year: 2014

Due to the outstanding physicochemical properties arising from its truly two-dimensional (2D) planar structure with a single-atom thickness, graphene exhibits great potential for use in sensors, catalysts, electrodes, and in biological applications, etc. With further developments in the theoretical understanding and assembly techniques, graphene should enable great changes both in scientific research and practical industrial applications. By the look of development, it is of fundamental and practical significance to translate the novel physical and chemical properties of individual graphene nanosheets into the macroscale by the assembly of graphene building blocks into macroscopic architectures with structural specialities and functional novelties. The combined features of a 2D planar structure and abundant functional groups of graphene oxide (GO) should provide great possibilities for the assembly of GO nanosheets into macroscopic architectures with different macroscaled shapes through various assembly techniques under different bonding interactions. Moreover, macroscopic graphene frameworks can be used as ideal scaffolds for the incorporation of functional materials to offset the shortage of pure graphene in the specific desired functionality. The advantages of light weight, supra-flexibility, large surface area, tough mechanical strength, and high electrical conductivity guarantee graphene-based architectures wide application fields. This critical review mainly addresses recent advances in the design and fabrication of graphene-based macroscopic assemblies and architectures and their potential applications. Herein, we first provide overviews of the functional macroscopic graphene materials from three aspects, i.e., 1D graphene fibers/ribbons, 2D graphene films/papers, 3D network-structured graphene monoliths, and their composite counterparts with either polymers or nano-objects. Then, we present the promising potential applications of graphene-based macroscopic assemblies in the fields of electronic and optoelectronic devices, sensors, electrochemical energy devices, and in water treatment. Last, the personal conclusions and perspectives for this intriguing field are given. © 2014 the Partner Organisations.

Jiao X.,Hefei University of Technology | Wang R.,East China University of Science and Technology
International Journal of Non-Linear Mechanics | Year: 2010

A stochastic model of neuronal population with excitatory and inhibitory connections is proposed, where excitatory synaptic dynamics is considered. Oscillatory synchronized firing patterns of a neuronal population by means of firing density are investigated. Numerical simulations using Fokker-Planck equation show that slow inhibitory connection contributes to oscillatory synchronized firing of the neuronal population, and synchronous activity is enhanced due to inhibitory connection. The effect of time delay on the oscillatory synchronized firing in the neuronal population using phase mode is explored. Numerical simulation indicates that short synaptic transmission delay can suppress oscillatory synchronized firing, but this suppression is instable. © 2008 Elsevier Ltd. All rights reserved.

Zhao L.-C.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Zhao L.-C.,Hefei University of Technology
Annals of Physics | Year: 2013

We study rogue waves of Bose-Einstein condensate (BEC) analytically in a time-dependent harmonic trap with a complex potential. Properties of the nonautonomous rogue waves are investigated analytically. It is reported that there are possibilities to 'catch' rogue waves through manipulating nonlinear interaction properly. The results provide many possibilities to manipulate rogue waves experimentally in a BEC system. © 2012 Elsevier Inc.

Ma J.,Southwest Jiaotong University | Lo S.M.,City University of Hong Kong | Song W.G.,Hefei University of Technology
Fire Safety Journal | Year: 2012

With the development of modern cities, numerous buildings over 40-storey have been constructed in recent decades. Fire safety issues, especially evacuation, are of the major concerns for building designers, occupants, as well as governments. To ensure the safety of ultra high-rise building evacuation, different performance-based designs have been proposed. In this study, we propose a quantitative and viable elevator aided ultra-high rise building evacuation model which simulates both pedestrian movement and elevator transportation. After validation and calibration, the proposed Ultra high-rise building Evacuation with Elevators (UEE) model is adopted to explore two main evacuation strategies, i.e., phased evacuation and total evacuation with the aid of elevators. In these two strategies, refuge floor plays an important part because it not only provides a place for temporarily stop, but also for the transition from stair evacuation into elevator evacuation. Thus, the effect of refuge floor interval on the high-rise building evacuation process is further investigated. It is found that the interval design of refuge floors has a direct relation with the characteristics of the elevators and building occupants. In the case that a proper ratio of the building occupants is transported to the ground level by fast elevators while others are evacuated by stairs, the evacuation process can reach an optimized state. © 2012 Elsevier Ltd.

Sharma S.,Hefei University of Technology | Sharma S.,University
Nonlinear Dynamics | Year: 2015

In this paper, a new lattice hydrodynamic traffic flow model is proposed by considering the driver’s anticipation effect (DAE) in sensing optimal current difference (OCD) for two-lane system. The effect of anticipation parameter on the stability of traffic flow is examined through linear stability analysis and shown that it can significantly enlarge the stability region on the phase diagram. Nonlinear analysis is conducted, and mKdV equation is derived to describe propagation behavior of a density wave near the critical point. The driver’s physical delay in sensing optimal current difference effect is also investigated and found that it has different effect on two-lane traffic based on whether lane changing is allowed or not. Simulation results are found in good agreement with the theoretical findings, which confirms that traffic jam can be suppressed efficiently by considering the DAEOCD effect in a two-lane traffic system. © Springer Science+Business Media Dordrecht 2015.

Xie S.,National University of Ireland | Lawlor P.G.,Teagasc | Frost J.P.,Hillsborough Co. Down | Hu Z.,Hefei University of Technology | Zhan X.,National University of Ireland
Bioresource Technology | Year: 2011

Anaerobic co-digestion of concentrated pig manure (PM) with grass silage (GS) at five different PM to GS volatile solid (VS) ratios of 1:0, 3:1, 1:1, 1:3 and 0:1 was evaluated by examining operation stability and methane (CH4) production potentials. The highest specific CH4 yields were 304.2 and 302.8ml CH4/g VS at PM to GS ratios of 3:1 and 1:1, respectively. The digestion systems failed at the ratio of 0:1. The lag phase lasted 29.5, 28.1, 24.6 and 21.3days at the ratios of 1:0, 3:1, 1:1 and 1:3, respectively. The daily methane yield was linearly correlated with the acetic acid concentration, indicating methane production was probably associated with acetoclastic methanogenesis. The hydrolysis constant linearly decreased with increasing the fraction of GS in the feedstock. This study recommends applying the PM to GS ratio of 1:1 in practice due to a high specific methane yield and a short lag phase. © 2011 Elsevier Ltd.

Zeng Q.,Hefei University of Technology
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2010

OBJECTIVE: In order to improve the rate of the heterotrophic nitrification, we screened and identified a high-efficient heterotrophic nitrifier, as well as studied its nitrification characteristics and nitrification conditions. METHODS: We obtained activated sludge samples from sewage and chemical fertilizer factories and farmland. We then utilized sodium citrate and ammonium chloride as carbon and nitrogen source. We used methods including domestication, gradient dilution of domestication liquid, isolation from streaking plate and color indicator as rapid nitrification detection. Finally a high-efficient heterotrophic nitrifier was obtained. We identified this strain according to its physiological, biochemical properties and the sequence analysis of 16S rDNA. After inoculating the strain into artificial ammonia-nitrogen wastewater, changes of nitrogen compounds were measured in order to understand the nitrification characteristics. Nitrification condition was also optimized by changing the carbon source, dissolved oxygen, C/N ratio, temperature and pH of the medium. RESULTS: The heterotrophic nitrifier was a gram-negative bacilli. It neither fermented glucose, nor produced indole. Oxidase and catalase tests were positive. It could produce alkali if organic salt was provided. The strain shared 99.7% sequence identity of its 16S rDNA with ES-SDK-3 of Alcaligenes sp. In the artificial wastewater with 182.30 mg/L ammonia nitrogen as initial concentration, the removal efficiency by the strain was 99. 8% after 30h cultivation. The average nitrogen removal rate was 9. 61 mg-N/L/h in its exponential phase. It produced almost no NO(2-)-N and NO(3-)-N in the entire nitrification process. The optimal carbon source is sodium citrate. Higher dissolved oxygen and C/N ratio favor its nitrification. When temperature is ranged from 30 degrees C to 35 degrees C and pH is ranged from 5.0 to 9.0, it can completely remove ammonia nitrogen. CONCLUSIONS: The strain was identified as Alcaligenes genus, and named as Alcaligenes sp. HN-S. Our research confirmed that the Alcaligenes sp. HN-S had significant advantages over heterotrophic nitrifiers that were screened previously with aspect of ammonia nitrogen removal rate. The research of its nitrification condition definitely provided necessary theory support for a new biology process to remove nitrogen with high efficiency.

Feng Z.-H.,Hefei University of Technology | Feng Z.-H.,Beijing Institute of Technology | Zou L.-L.,CAS Institute of Policy and Management | Wei Y.-M.,Beijing Institute of Technology
Energy | Year: 2011

In this paper, the consumer lifestyle approach is applied to analyze the impact of consumption by urban and rural households on energy use and CO2 emissions for different regions and income levels in China. Grey Model is used to compare the relationship between energy consumption, consumption expenditure and CO2 emissions for different lifestyles. The results show that direct energy consumption is diverse for urban households and simple for rural households in China. Direct energy consumption and CO2 emissions are increasing faster for urban than for rural households. Indirect energy consumption and CO2 emissions for urban households are much greater than the direct consumption values. The total indirect energy consumption and CO2 emissions differ by regions and the structures are different, but the latter differences are not obvious. The impact of household income is enormous. Indirect energy consumption and CO2 emissions are higher for high-income than for low-income households. The structural difference for indirect energy consumption and CO2 emissions for households with different income levels is significant. The higher the income, the more diverse is the energy consumption and CO2 emission structure. The structures for indirect energy use and CO2 emissions are diverse for urban households, but simple for rural households. © 2010.

Wang Y.-M.,Fuzhou University | Wang Y.-M.,Hefei University of Technology
International Journal of Production Research | Year: 2012

Quality function deployment (QFD) is often implemented to transform customer requirements (CRs) into the engineering design requirements (DRs) of a new product. Prioritising engineering DRs is essential to reasonably allocate resources for the new product development, and often must be done under uncertainty due to the vagueness and impreciseness of the judgments made by customers and QFD team members, and is a typical group decision behaviour that requires the active participation of multiple customers and multiple QFD design team members. Fuzzy set theory provides a theoretical basis for solving such group decision-making problems under uncertainty. Existing approaches for prioritising DRs under uncertainty usually simplify the group decision-making problem as non-group decision making for solution by simply aggregating individuals opinions using their arithmetic averages. This paper proposes a different fuzzy group decision-making procedure for prioritising DRs under uncertainty. The proposed approach does not aggregate the individual judgments of customers and QFD design team members, but rather aggregates the technical importance ratings of DRs, and can produce more rational and robust priority rankings for DRs through fuzzy normalisation. A real design case of a flexible manufacturing system (FMS) is examined to show the effectiveness and the potential applications of the proposed approach. Results are compared with those obtained by two known approaches. © 2012 Copyright Taylor and Francis Group, LLC.

Ge T.,Hefei University of Technology | He K.,Microsoft | Ke Q.,Microsoft | Sun J.,Microsoft
IEEE Transactions on Pattern Analysis and Machine Intelligence | Year: 2014

Product quantization (PQ) is an effective vector quantization method. A product quantizer can generate an exponentially large codebook at very low memory/time cost. The essence of PQ is to decompose the high-dimensional vector space into the Cartesian product of subspaces and then quantize these subspaces separately. The optimal space decomposition is important for the PQ performance, but still remains an unaddressed issue. In this paper, we optimize PQ by minimizing quantization distortions w.r.t the space decomposition and the quantization codebooks. We present two novel solutions to this challenging optimization problem. The first solution iteratively solves two simpler sub-problems. The second solution is based on a Gaussian assumption and provides theoretical analysis of the optimality. We evaluate our optimized product quantizers in three applications: (i) compact encoding for exhaustive ranking , (ii) building inverted multi-indexing for non-exhaustive search , and (iii) compacting image representations for image retrieval. In all applications our optimized product quantizers outperform existing solutions. © 2014 IEEE.

Leng C.,National University of Singapore | Zhang W.,Hefei University of Technology
Statistics and Computing | Year: 2014

Quantile regression has become a powerful complement to the usual mean regression. A simple approach to use quantile regression in marginal analysis of longitudinal data is to assume working independence. However, this may incur potential efficiency loss. On the other hand, correctly specifying a working correlation in quantile regression can be difficult. We propose a new quantile regression model by combining multiple sets of unbiased estimating equations. This approach can account for correlations between the repeated measurements and produce more efficient estimates. Because the objective function is discrete and non-convex, we propose induced smoothing for fast and accurate computation of the parameter estimates, as well as their asymptotic covariance, using Newton-Raphson iteration. We further develop a robust quantile rank score test for hypothesis testing. We show that the resulting estimate is asymptotically normal and more efficient than the simple estimate using working independence. Extensive simulations and a real data analysis show the usefulness of the method. © 2012 Springer Science+Business Media New York.

Jiang B.,University of New Mexico | Jiang B.,Hefei University of Technology | Yang M.,CAS Wuhan Institute of Physics and Mathematics | Xie D.,Nanjing University | And 2 more authors.
Chemical Society Reviews | Year: 2016

Dissociative chemisorption is the initial and often rate-limiting step in many heterogeneous processes. As a result, an in-depth understanding of the reaction dynamics of such processes is of great importance for the establishment of a predictive model of heterogeneous catalysis. Overwhelming experimental evidence has suggested that these processes have a non-statistical nature and excitations in various reactant modes have a significant impact on reactivity. A comprehensive characterization of the reaction dynamics requires a quantum mechanical treatment on a global potential energy surface. In this review, we summarize recent progress in constructing high-dimensional potential energy surfaces for polyatomic molecules interacting with transition metal surfaces based on the plane-wave density functional theory and in quantum dynamical studies of dissociative chemisorption on these potential energy surfaces. A special focus is placed on the mode specificity and bond selectivity in these gas-surface collisional processes, and their rationalization in terms of the recently proposed Sudden Vector Projection model. © 2016 The Royal Society of Chemistry.

Zhang K.Z.K.,Hefei University of Technology | Cheung C.M.K.,Hong Kong Baptist University | Lee M.K.O.,City University of Hong Kong
International Journal of Information Management | Year: 2014

The prevalence of social media has provided consumers with many opportunities to post online reviews on a wide range of products on the Internet. In this study, we attempt to investigate the moderating effect of inconsistent reviews (i.e., a mix of positive and negative reviews) on consumers' purchase decision. We further examine whether the effect will differ from female to male consumers. We explain the moderating effect and its gender differences based on the theory of reasoned action, trust literature, and information processing literature. The research hypotheses are empirically tested in a laboratory experiment using structural equation modeling approach. Our findings show that consumers' cognitive trust to online retailers affects emotional trust, which further leads to purchase intention. When consumers are exposed to inconsistent reviews, the influence of emotional trust on purchase intention is significantly stronger. Moreover, the moderating effect of inconsistent reviews is stronger for female consumers than for male consumers. We expect that this study can enrich the understanding of how inconsistent reviews play a role in consumers' online shopping decision. Online retailers may apply our findings and leverage the influence of online consumer reviews in social media. Implications for both researchers and practitioners are discussed. © 2013 Elsevier Ltd.

Gao Y.,Tsinghua National Laboratory for Information Sciences and Technology | Wang M.,Hefei University of Technology | Tao D.,Intelligent Systems Technology, Inc. | Ji R.,Columbia University | Dai Q.,Tsinghua National Laboratory for Information Sciences and Technology
IEEE Transactions on Image Processing | Year: 2012

View-based 3-D object retrieval and recognition has become popular in practice, e.g., in computer aided design. It is difficult to precisely estimate the distance between two objects represented by multiple views. Thus, current view-based 3-D object retrieval and recognition methods may not perform well. In this paper, we propose a hypergraph analysis approach to address this problem by avoiding the estimation of the distance between objects. In particular, we construct multiple hypergraphs for a set of 3-D objects based on their 2-D views. In these hypergraphs, each vertex is an object, and each edge is a cluster of views. Therefore, an edge connects multiple vertices. We define the weight of each edge based on the similarities between any two views within the cluster. Retrieval and recognition are performed based on the hypergraphs. Therefore, our method can explore the higher order relationship among objects and does not use the distance between objects. We conduct experiments on the National Taiwan University 3-D model dataset and the ETH 3-D object collection. Experimental results demonstrate the effectiveness of the proposed method by comparing with the state-of-the-art methods. © 1992-2012 IEEE.

Lin S.,University of Waterloo | Lin S.,Hefei University of Technology | Beakhouse G.P.,Geological Survey of Canada
Geology | Year: 2013

The Hemlo gold deposit (~700 t Au; northwestern Ontario, Canada) is hosted in a shear zone in the Hemlo greenstone belt, which is a synclinal keel between two granitoid domes. The dome-and-keel structure formed by diapirism and sagduction (vertical tectonism) that was synchronous with regional horizontal shearing (horizontal tectonism). Mineralization occurred during shearing, and mineralizing fluids probably had a magmatic source that is interpreted to be related to syntectonic mantle-derived granodiorite (sanukitoid) intrusions. The gold deposit, the intrusions, and the hosting shear zone all developed within a regime characterized by synchronous vertical and horizontal tectonism. They were all possibly linked to a range of processes associated with the accretionary growth and stabilization of the craton, in particular slab breakoff and the associated extensional orogenic collapse following terrane accretion. © 2013 Geological Society of America.

Zhao X.,University of Texas at Austin | Zhao X.,Donghua University | Zhang L.,University of Texas at Austin | Murali S.,University of Texas at Austin | And 4 more authors.
ACS Nano | Year: 2012

Figure Persented: Manganese dioxide (MnO 2) particles 2-3 nm in size were deposited onto a porous "activated microwave expanded graphite oxide" (aMEGO) carbon scaffold via a self-controlled redox process. Symmetric electrochemical capacitors were fabricated that yielded a specific capacitance of 256 F/g (volumetric: 640 F/cm 3) and a capacitance retention of 87.7% after 1000 cycles in 1 M H 2SO 4; when normalized to MnO 2, the specific capacitance was 850 F/g. Asymmetric electrochemical capacitors were also fabricated with aMEGO/MnO 2 as the positive electrode and aMEGO as the negative electrode and had a power density of 32.3 kW/kg (for an energy density of 20.8 Wh/kg), an energy density of 24.3 Wh/kg (for a power density of 24.5 kW/kg), and a capacitance retention of 80.5% over 5000 cycles. © 2012 American Chemical Society.

Yu J.,Xiamen University | Tao D.,Intelligent Systems Technology, Inc. | Wang M.,Hefei University of Technology
IEEE Transactions on Image Processing | Year: 2012

Recent years have witnessed a surge of interest in graph-based transductive image classification. Existing simple graph-based transductive learning methods only model the pairwise relationship of images, however, and they are sensitive to the radius parameter used in similarity calculation. Hypergraph learning has been investigated to solve both difficulties. It models the high-order relationship of samples by using a hyperedge to link multiple samples. Nevertheless, the existing hypergraph learning methods face two problems, i.e., how to generate hyperedges and how to handle a large set of hyperedges. This paper proposes an adaptive hypergraph learning method for transductive image classification. In our method, we generate hyperedges by linking images and their nearest neighbors. By varying the size of the neighborhood, we are able to generate a set of hyperedges for each image and its visual neighbors. Our method simultaneously learns the labels of unlabeled images and the weights of hyperedges. In this way, we can automatically modulate the effects of different hyperedges. Thorough empirical studies show the effectiveness of our approach when compared with representative baselines. © 2012 IEEE.

Zhang W.,Hefei University of Technology | Leng C.,National University of Singapore
Biometrika | Year: 2012

We propose new regression models for parameterizing covariance structures in longitudinal data analysis. Using a novel Cholesky factor, the entries in this decomposition have a moving average and log-innovation interpretation and are modelled as linear functions of covariates. We propose efficient maximum likelihood estimates for joint mean-covariance analysis based on this decomposition and derive the asymptotic distributions of the coefficient estimates. Furthermore, we study a local search algorithm, computationally more efficient than traditional all subset selection, based on bic for model selection, and show its model selection consistency. Thus, a conjecture of Pan & MacKenzie (2003) is verified. We demonstrate the finite-sample performance of the method via analysis of data on CD4 trajectories and through simulations. © 2011 Biometrika Trust.

An N.,Hefei University of Technology | Zhao W.,Lanzhou University | Wang J.,Lanzhou University | Shang D.,University College of Applied Sciences | Zhao E.,North China Electrical Power University
Energy | Year: 2013

For accurate electricity demand forecasting, this paper proposes a novel approach, MFES, that combines a multi-output FFNN (feedforward neural network) with EMD (empirical mode decomposition)-based signal filtering and seasonal adjustment. In electricity demand forecasting, noise signals, caused by various unstable factors, often corrupt demand series. To reduce these noise signals, MFES first uses an EMD-based signal filtering method which is fully data-driven. Secondly, MFES removes the seasonal component from the denoised demand series and models the resultant series using FFNN model with a multi-output strategy. This multi-output strategy can overcome the limitations of common multi-step-ahead forecasting approaches, including error amplification and the neglect of dependency between inputs and outputs. At last, MFES obtains the final prediction by restoring the season indexes back to the FFNN forecasts. Using the half-hour electricity demand series of New South Wales in Australia, this paper demonstrates that the proposed MFES model improves the forecasting accuracy noticeably comparing with existing models. © 2012 Elsevier Ltd.

Xiong J.,Hefei University of Technology | Lam J.,University of Hong Kong | Shu Z.,University of Southampton | Mao X.,University of Strathclyde
IEEE Transactions on Automatic Control | Year: 2014

This technical note is concerned with the stability analysis of continuous-time switched systems with a random switching signal. The switching signal manifests its characteristics with that the dwell time in each subsystem consists of a fixed part and a random part. The stochastic stability of such switched systems is studied using a Lyapunov approach. A necessary and sufficient condition is established in terms of linear matrix inequalities. The effect of the random switching signal on system stability is illustrated by a numerical example and the results coincide with our intuition. © 2013 IEEE.

Chen L.-F.,Anhui University of Science and Technology | Huang Z.-H.,Anhui University of Science and Technology | Liang H.-W.,Anhui University of Science and Technology | Yao W.-T.,Hefei University of Technology | And 2 more authors.
Energy and Environmental Science | Year: 2013

To meet the pressing demands for portable and flexible equipment in contemporary society, it is strongly required to develop next-generation inexpensive, flexible, lightweight, and sustainable supercapacitor systems with large power densities, long cycle life, and good operational safety. Here, we fabricate a flexible all-solid-state supercapacitor device with nitrogen-doped pyrolyzed bacterial cellulose (p-BC-N) as the electrode material via a low-cost, eco-friendly, low-temperature, and scalable fabrication hydrothermal synthesis. The pliable device can reversibly deliver a maximum power density of 390.53 kW kg-1 and exhibits a good cycling durability with ∼95.9% specific capacitance retained after 5000 cycles. Therefore, this nitrogen-doped carbon nanofiber electrode material holds significant promise as a flexible, efficient electrode material. © 2013 The Royal Society of Chemistry.

Bian Y.,Shanghai University | He P.,Hefei University of Technology | Xu H.,Anhui University
Energy Policy | Year: 2013

In the process of setting operational targets to achieve sustainable development of economy, environment and natural resources, estimation of potential energy saving and potential CO2 emission reduction becomes extremely important. This estimation can be conducted based on the energy efficiency evaluation for different decision-making units (DMUs) by data envelopment analysis (DEA). Non-fossil energy is an important component of energy consumption in China, and it has great impacts on energy efficiency and energy-related carbon dioxide (CO2) emissions. This paper proposes a non-radial DEA model to evaluate regional energy efficiencies in China. In the proposed model, non-fossil energy is treated as a fixed input. Based on the model, a method of measuring potential energy saving and CO2 emission reduction for efficiency improvement is also presented. The proposed approaches are illustrated by using a regional dataset in China. Based on the application results, some implications for improving energy efficiency and reducing CO2 emissions in China are provided. © 2013 Elsevier Ltd.

Du H.,Hefei University of Technology | Du H.,Nanjing Southeast University | Li S.,Nanjing Southeast University
Automatica | Year: 2014

To solve the problem of attitude synchronization for a group of flexible spacecraft during formation maneuvers, a distributed attitude cooperative control strategy is investigated in this paper. Based on the backstepping design and the neighbor-based design rule, a distributed attitude control law is constructed step by step. Using cascaded systems' theory and graph theory, it is shown that the attitude synchronization is achieved asymptotically and the induced vibrations by flexible appendages are simultaneously suppressed under the proposed control law. © 2013 Elsevier Ltd. All rights reserved.

Yang C.,CAS Dalian Institute of Chemical Physics | Yang C.,Hefei University of Technology | Zhou B.,CAS Dalian Institute of Chemical Physics | Miao S.,CAS Dalian Institute of Chemical Physics | And 3 more authors.
Journal of the American Chemical Society | Year: 2013

A facile solution-phase route was developed to synthesize a family of monodisperse Cu2Ge(S3-xSex) alloyed nanocrystals (NCs) with controlled composition across the entire range (0 ≤ x ≤ 3). The band gaps of the resultant NCs can be engineered by tuning the compositions with a nearly linear relationship between them. The band structures of the NCs were studied by cyclic voltammetry and UV-vis absorption spectroscopy. The conducting behavior was revealed to be p-type for these NCs by photoelectrochemical measurements. Their photovoltaic applicability was finally assessed by fabricating solar cells with the Cu2Ge(S2Se) NCs as light harvester and CdS nanorods as electron conducting materials. © 2013 American Chemical Society.

He L.,Zhejiang University | Zhang L.,Wenzhou University | Liang H.,Hefei University of Technology
Polymer | Year: 2010

Mixtures of diblock copolymers (DBCPs) and mono- or bidisperse nanorods (NRs), are systematically investigated via dissipative particle dynamics simulations. For the mixtures of DBCPs and monodisperse NRs, we investigate the effects of the nanorod (NR) volume fraction, NR length, and interaction strength between blocks and NRs on the self-assembly of the composites. For the mixtures of DBCPs and bidisperse NRs in which the NRs are different in length, the binary NRs with varied compositions can induce various morphological transitions, as well as present the uniform orientations and discriminative distributions. The inherent mechanism for driving such rich phase behaviors can be further exploited on the basis of considering the enthalpic and entropic effects. The results provide some guidelines for engineering nanocomposites with the desired morphologies and functions. © 2010 Elsevier Ltd.

Zhu L.,Hefei University of Technology | Zhu L.,CAS Institute of Policy and Management | Fan Y.,CAS Institute of Policy and Management
Energy | Year: 2010

This paper applies portfolio theory to evaluate China's 2020-medium-term plans for generating technologies and its generating portfolio. With reference to the risk of relevant generating-cost streams, the paper discusses China's future development of efficient (Pareto optimal) generating portfolios that enhance energy security in different scenarios, including CO2-emission-constrained scenarios. This research has found that the future adjustment of China's planned 2020 generating portfolio can reduce the portfolio's cost risk through appropriate diversification of generating technologies, but a price will be paid in the form of increased generating cost. In the CO2-emission-constrained scenarios, the generating-cost risk of China's planned 2020 portfolio is even greater than that of the 2005 portfolio, but increasing the proportion of nuclear power in the generating portfolio can reduce the cost risk effectively. For renewable-power generation, because of relatively high generating costs, it will be necessary to obtain stronger policy support to promote renewable-power development. © 2009 Elsevier Ltd. All rights reserved.

Huang X.,Hefei University of Technology | Huang X.,Chinese University of Hong Kong | Li J.,Academia Sinica, China | Li J.,Chinese University of Hong Kong | Xin Z.,Chinese University of Hong Kong
Communications in Mathematical Physics | Year: 2011

We prove that the maximum norm of the deformation tensor of velocity gradients controls the possible breakdown of smooth(strong) solutions for the 3-dimensional (3D) barotropic compressible Navier-Stokes equations. More precisely, if a solution of the 3D barotropic compressible Navier-Stokes equations is initially regular and loses its regularity at some later time, then the loss of regularity implies the growth without bound of the deformation tensor as the critical time approaches. Our result is the same as Ponce's criterion for 3-dimensional incompressible Euler equations (Ponce in Commun Math Phys 98:349-353, 1985). In addition, initial vacuum states are allowed in our cases. © 2010 Springer-Verlag.

Leung K.C.-F.,Hong Kong Baptist University | Leung K.C.-F.,Chinese University of Hong Kong | Xuan S.,Chinese University of Hong Kong | Xuan S.,Hefei University of Technology | And 6 more authors.
Chemical Society Reviews | Year: 2012

This critical review provides an overview of current research activities that focused on the synthesis and application of multi-functional gold and iron oxide (Au-Fe xO y) hybrid nanoparticles and nanocomposites. An introduction of synthetic strategies that have been developed for generating Au-Fe xO y nanocomposites with different nanostructures is presented. Surface functionalisation and bioconjugation of these hybrid nanoparticles and nanocomposites are also reviewed. A variety of applications such as theranostics, gene delivery, biosensing, cell sorting, bio-separation, and catalysis is discussed and highlighted. Finally, future trends and perspectives of these sophisticated nanocomposites are outlined. Underpinning the fundamental requirements for effectively forming Au-Fe xO y hybrid nanocomposite materials would shed light on future development of nanotheranostics, nanomedicines, and chemical technologies. It would be interesting to investigate such multi-component composite nanomaterials with different novel morphologies in the near future to advance chemistry, biology, medicine, and engineering multi-disciplinary research (120 references). © 2012 The Royal Society of Chemistry.

Zhao L.,Hefei University of Technology
Finite Fields and their Applications | Year: 2014

We consider restricted sumsets over field F. Let C = {a1 + ⋯ +a n: a1 ∈ A1, ⋯, a n∈An, ai - aj ∉ S ij if i ≠ j }, where Sij(1≤i≠j≤n) are finite subsets of F with cardinality m, and A1,⋯, An are finite nonempty subsets of F with |A1|=⋯=|An|=k. Let p(F) be the additive order of the identity of F. It is proved that |C|≥min{p(F),n(k-1)-mn(n-1)+1} if p(F)>mn. This conclusion refines the result of Hou and Sun [11]. © 2014 Elsevier Inc.

Lu W.,City University of Hong Kong | Lu W.,Hefei University of Technology | Lu Y.Y.,City University of Hong Kong
Journal of Lightwave Technology | Year: 2012

Photonic crystal fibers (PCFs) with many air holes and complicated geometries can be difficult to analyze using conventional waveguide mode solvers such as the finite element method. Boundary integral equation (BIE) methods are suitable for PCFs, since they formulate eigenvalue problems only on the interfaces and are capable of computing leaky modes accurately. To improve the efficiency, it is desirable to have high-order BIE methods that calculate the minimum number of functions on the interfaces. Existing BIE methods calculate two or four functions on the interfaces, but high-order implementations are only available for those with four functions. In this paper, a new high-order BIE method is developed and it calculates two functions on the interfaces. Numerical results indicate that the new BIE method achieves exponential convergence and extremely high accuracy. © 2012 IEEE.

Wang Y.,Hefei University of Technology
Journal of Geometry and Physics | Year: 2011

We investigate generalized holomorphic structures in generalized complex geometry. We find that a generalized holomorphic vector bundle carries a generalized complex structure on its total space if some additional conditions hold. We prove that generalized holomorphicity is equivalent to the integrability of a distribution on the total space, and a family of linear Dirac structures associated with this distribution is a generalized complex structure if a further condition holds. Under the same condition, we also prove that local generalized holomorphic frames exist around a regular point. © 2011 Elsevier B.V.

Linyuan L.L.,University of Electronic Science and Technology of China | Linyuan L.L.,University of Shanghai for Science and Technology | Linyuan L.L.,University of Fribourg | Zhou T.,University of Electronic Science and Technology of China | Zhou T.,Hefei University of Technology
Physica A: Statistical Mechanics and its Applications | Year: 2011

Link prediction in complex networks has attracted increasing attention from both physical and computer science communities. The algorithms can be used to extract missing information, identify spurious interactions, evaluate network evolving mechanisms, and so on. This article summaries recent progress about link prediction algorithms, emphasizing on the contributions from physical perspectives and approaches, such as the random-walk-based methods and the maximum likelihood methods. We also introduce three typical applications: reconstruction of networks, evaluation of network evolving mechanism and classification of partially labeled networks. Finally, we introduce some applications and outline future challenges of link prediction algorithms. © 2010 Elsevier B.V. All rights reserved.

Zhou B.,Hefei University of Technology
Pakistan Journal of Pharmaceutical Sciences | Year: 2014

Kinetics of chromium (VI) reduction and phenol biodegradation by a pure culture of Pseudomonas sp. JF122 was studied. High inoculum (volume) increased both chromium (VI) reduction and phenol biodegradation velocity, which are ascribable to shorter acclimation period requirement for cell growth. Haldane's kinetics model adequately described the substrate kinetics with kinetic constants μmax1=0.113 h-1, Ks1=0.4009mM, Ki1=5.165mM for chromium (VI) reduction and μmax2=0.3081 h-1, Ks2=7.411mM Ki2=2.511mM for phenol biodegradation. Further, the growth yield for phenol biodegradation and chromium (VI) reduction were 30.6mg cell/mmol phenol and 8880.2mg cell/mmol Cr (VI), respectively.

Zhu L.,CAS Institute of Policy and Management | Zhu L.,Hefei University of Technology | Fan Y.,CAS Institute of Policy and Management
Applied Energy | Year: 2011

This paper establishes a carbon capture and storage (CCS) investment evaluation model based on real options theory considering uncertainties from the existing thermal power generating cost, carbon price, thermal power with CCS generating cost, and investment in CCS technology deployment. The model aims to evaluate the value of the cost saving effect and amount of CO2 emission reduction through investing in newly-built thermal power with CCS technology to replace existing thermal power in a given period from the perspective of power generation enterprises. The model is solved by the Least Squares Monte Carlo (LSM) method. Since the model could be used as a policy analysis tool, China is taken as a case study to evaluate the effects of regulations on CCS investment through scenario analysis. The findings show that the current investment risk of CCS is high, climate policy having the greatest impact on CCS development. Thus, there is an important trade off for policy makers between reducing greenhouse gas emissions and protecting the interests of power generation enterprises. The research presented would be useful for CCS technology evaluation and related policy-making. © 2011.

Li Z.-H.,Hefei University of Technology
Physica A: Statistical Mechanics and its Applications | Year: 2011

We study the roles of life process in cooperation in spatial prisoner's dilemma games. We assume each individual to have a finite lifetime which is correlated with its current fitness. The correlation is controlled by a free parameter w. Simulation results show that the dynamical changing of individuals' lifetime can promote cooperation. Besides, there exists an optimal region for the parameter w that leads to the highest cooperation level. We understand these results by analyzing the spatial patterns of the system and the distributions of the diversified fitness and lifetime values. Our results may help build more realistic models concerning individuals' life process and illuminate its roles in cooperation. © 2011 Elsevier B.V. All rights reserved.

Fan N.,CAS Guangzhou Institute of Biomedicine and Health | Fan N.,Hefei University of Technology | Lai L.,CAS Guangzhou Institute of Biomedicine and Health
Journal of Genetics and Genomics | Year: 2013

Genetically modified animal models are important for understanding the pathogenesis of human disease and developing therapeutic strategies. Although genetically modified mice have been widely used to model human diseases, some of these mouse models do not replicate important disease symptoms or pathology. Pigs are more similar to humans than mice in anatomy, physiology, and genome. Thus, pigs are considered to be better animal models to mimic some human diseases. This review describes genetically modified pigs that have been used to model various diseases including neurological, cardiovascular, and diabetic disorders. We also discuss the development in gene modification technology that can facilitate the generation of transgenic pig models for human diseases. © 2012.

Ju M.-G.,Hefei University of Technology | Liang W.,Xiamen University
Journal of Physical Chemistry C | Year: 2013

A step-by-step theoretical protocol based on the density functional theory (DFT) and time-dependent DFT (TD-DFT) at both the molecular and periodic levels have been performed to study a zinc porphyrin complex (named YDoc) sensitized TiO2 solar cell including dye excitations, electron injection, the regeneration of photooxidized dyes and the effect of electrolyte additives. Our study reveals the possibility of a favorable electron transfer from the excited dye to the semiconductor conduction band (CB) and suggests three possible pathways of the electron injection from the dye to the nanoparticle (TiO 2)38. One is the direct one-step injection by photoexcitation, and the other two are from the different parts of the excited dye to the nanoparticle. The influence of the electrolyte composition on the geometric and electronic features of the dye/TiO2 system has also been studied. It is found that, with the additive of the lithium ion, the energy gap between the LUMO of dye and the TiO2 CB edge increases, which subsequently increases the driving force for the ultrafast excited-state electron injection, contrary to the effect of 4-tert-butylpyridine additive. The computational results of the oxidized dye interacting with I- and I2- reveal that there are a few possible mechanisms for the regeneration of oxidized dye. The effective mechanisms of the regeneration are suggested. © 2013 American Chemical Society.

Ye S.,Anhui University | Qiu L.-G.,Anhui University | Yuan Y.-P.,Anhui University | Zhu Y.-J.,Anhui University | And 2 more authors.
Journal of Materials Chemistry A | Year: 2013

Because of their potential application in the conversion of solar energy to chemical energy, the development of semiconductor photocatalysts that have high reactivity under visible light has received great attention. In the present work, we illustrate the design and fabrication of magnetically separable polymeric carbon nitride photocatalysts, i.e. Fe2O 3/g-C3N4 composite photocatalysts, a novel type of visible light driven photocatalyst with a cost-effective recovery manner. The obtained Fe2O3/g-C3N4 composite catalysts with different Fe2O3 contents were characterized by powder X-ray diffraction (PXRD), high-resolution transmission electron microscopy (HRTEM), UV-vis diffuse reflection spectroscopy (DRS), vibration sample magnetometry (VSM) and thermogravimetric analysis (TGA). The saturation magnetization at 300 K varies from 0.37 to 1.56 emu g-1, depending on the different Fe2O3 contents (2.8-11.6 wt%) in the Fe2O3/g-C3N4 composites, clearly indicating the excellent magnetic separation characteristics of the as-prepared photocatalysts. Remarkably, the photocatalytic activity of the magnetic Fe 2O3/g-C3N4 photocatalysts under visible light irradiation was increased up to 1.8 times for the photodegradation of Rhodamine B (RhB) under visible light irradiation compared with the conventional pure g-C3N4 photocatalyst. A possible mechanism for the enhanced photocatalytic activity of the Fe2O 3/g-C3N4 composite photocatalyst was also proposed to guide the further improvement of their photocatalytic activity. © 2013 The Royal Society of Chemistry.

Lu P.,Hefei University of Technology
Tribology Letters | Year: 2015

Abstract For small particles adhesion to compliant substrates, the ratio of the contact radius to the particle radius can be rather large. To take into consideration the effects in modeling small sphere contacts, the extended solutions of Johnson-Kendall-Roberts (JKR) adhesive contact theory by Maugis for exact sphere contacts are further modified in this work by incorporating the interfacial adhesion energy defined on real spherical contact area rather than its projected flat area. The numerical calculations indicate that the contact radius of an adhesive sphere contact under zero loads predicted by the modified sphere model is between the predicted results by JKR and Maugis models for small sphere contacts and approach to JKR results for large sphere contacts. By comparing with the published experiment results on particles adhesion, it is shown that the predicted results by the modified sphere contact model agree with the experiment results better compared with JKR and Maugis predicted results. © Springer Science+Business Media New York 2015.

Shi L.,Hefei University of Technology | Li Q.,Chinese University of Hong Kong
CrystEngComm | Year: 2011

Quaternary Cu2ZnSnSe4 single crystalline nanosheets have been synthesized in a controlled manner with a convenient solvothermal approach by simply modifying the reaction conditions. The presence of ethylenediamine (En) plays a key role in the preparation of Cu 2ZnSnSe4 nanosheets while the thickness of the as-prepared Cu2ZnSnSe4 nanosheets is strongly dependent on the amount of En. The formation mechanism of Cu2ZnSnSe4 nanosheets was discussed. The products were characterized using X-ray powder diffraction, Raman, energy dispersive X-ray spectrometry, transmission electron microscopy, scanning electron microscopy and UV-Vis spectrophotometry. © 2011 The Royal Society of Chemistry.

Shi F.,Jiangsu University | Gong L.-Z.,Hefei University of Technology
Angewandte Chemie - International Edition | Year: 2012

Teamwork: Through relay catalysis by a Ru II complex and a chiral phosphoric acid ((S)-BPA in the scheme) recently developed by Zhou's group, hydrogen gas can act as the terminal reductant in the catalytic asymmetric hydrogenation of heterocycles. This is a completely new concept in the area of asymmetric hydrogenation. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang Y.,Sun Yat Sen University | Lu Y.-X.,Sun Yat Sen University | Liu J.,Hefei University of Technology | Yang C.,Sun Yat Sen University | And 2 more authors.
PLoS Genetics | Year: 2013

Insect fat body is the organ for intermediary metabolism, comparable to vertebrate liver and adipose tissue. Larval fat body is disintegrated to individual fat body cells and then adult fat body is remodeled at the pupal stage. However, little is known about the dissociation mechanism. We find that the moth Helicoverpa armigera cathepsin L (Har-CL) is expressed heavily in the fat body and is released from fat body cells into the extracellular matrix. The inhibitor and RNAi experiments demonstrate that Har-CL functions in the fat body dissociation in H. armigera. Further, a nuclear protein is identified to be transcription factor Har-Relish, which was found in insect immune response and specifically binds to the promoter of Har-CL gene to regulate its activity. Har-Relish also responds to the steroid hormone ecdysone. Thus, the dissociation of the larval fat body is involved in the hormone (ecdysone)-transcription factor (Relish)-target gene (cathepsin L) regulatory pathway. © 2013 Zhang et al.

Tian J.-S.,Nanyang Technological University | Ng K.W.J.,Nanyang Technological University | Wong J.-R.,Nanyang Technological University | Loh T.-P.,Hefei University of Technology | Loh T.-P.,Nanyang Technological University
Angewandte Chemie - International Edition | Year: 2012

The metal-free amination of different aldehydes is catalyzed by hypoiodite, which is generated by employing commercially available sodium percarbonate as the co-oxidant. This approach has several advantages: it is a metal-free oxidation that works under mild reaction conditions; furthermore, it has a wide substrate scope and does not give toxic by-products from the co-oxidant that is used. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zheng Y.-F.,Hefei University of Technology
Geochemical Journal | Year: 2011

Theoretical and experimental aspects of oxygen isotope fractionation in carbonate minerals are critically examined based on a direct comparison of fractionation factors for carbonate-water systems. The results show good agreement between theory and experiment in most cases. In particular, theoretical fractionation factors calculated by the statisticomechanics method and the increment method are in good agreement with the experimental values for dolomite, siderite, witherite, strontianite and cerussite. These agreements provide corroboration that the two entirely independent approaches of calculation are generally capable of producing thermodynamic equilibrium fractionation factors for the most carbonate-water systems. In particular, the merit of the increment method relative to the statistico-mechanics method is evident for crystalline minerals because it enables the systematic and accurate predictions of oxygen isotope fractionation factors for different structures and compositions of crystalline minerals based only on their crystal chemistry. Thus, the increment method has no limitations to the calculations as commonly encountered by the statistico-mechanics method. Nevertheless, complexity in oxygen isotope fractionations between calcite and the other carbonate minerals can be caused by the oxygen isotope inheritance during polymorphic transformation from aragonite to calcite and by the isotope salt effect on the other carbonates in the presence of aqueous fluids. Therefore, caution must be exercised when interpreting possible disagreements between theory and experiment because of the kinetic effects. In the extreme case, equilibrium oxygen isotope fractionation factors for single carbonate-water systems could be either underestimated or overestimated by one of the theoretical and experimental methods. Copyright © 2011 by The Geochemical Society of Japan.

Gan M.,Central South University | Gan M.,Hefei University of Technology | Peng H.,Central South University
Applied Soft Computing Journal | Year: 2012

Varying-coefficient models have attracted great attention in nonlinear time series analysis recently. In this paper, we consider a semi-parametric functional-coefficient autoregressive model, called the radial basis function network-based state-dependent autoregressive (RBF-AR) model. The stability conditions and existing conditions of limit cycle of the RBF-AR model are discussed. An efficient structured parameter estimation method and the modified multi-fold cross-validation criterion are applied to identify the RBF-AR model. Application of the RBF-AR model to the famous Canadian lynx data is presented. The forecasting capability of the RBF-AR model is compared to those of other competing time series models, which shows that the RBF-AR model is as good as or better than other models for the postsample forecasts. © 2011 Elsevier B.V. All rights reserved.

Eckenhoff W.T.,University of Rochester | McNamara W.R.,College of William and Mary | Du P.,Hefei University of Technology | Eisenberg R.,University of Rochester
Biochimica et Biophysica Acta - Bioenergetics | Year: 2013

The generation of H2 from protons and electrons by complexes of cobalt has an extensive history. During the past decade, interest in this subject has increased as a result of developments in hydrogen generation that are driven electrochemically or photochemically. This article reviews the subject of hydrogen generation using Co complexes as catalysts and discusses the mechanistic implications of the systems studied for making H2. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems. © 2013 Elsevier B.V. All rights reserved.

Wang W.-G.,Hefei University of Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2016

For fermionic fields with nonzero mass, it is shown that the spinor factor of the anticommutation relation between creation and annihilation operators can be justified in a natural way, based on basic properties of Lorentz-invariant inner product in Hilbert space. Furthermore, from the physical point that predictions for measurement results should take real and definite values, we examine the basic requirements for inner product and propose to make certain relaxation to them. Under the relaxed requirements, there exists an alternative way of introducing the anticommutation relation, independent of the mass. In a theory with the latter type of anticommutation relation, the ultraviolet divergence may become less serious than that met in ordinary theories. © 2016 American Physical Society.

Zhang S.B.,Hefei University of Technology | Wang J.G.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Janev R.K.,Macedonian Academy of science and Arts
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

The effects of Coulomb interaction screening on electron-hydrogen-atom elastic and excitation scattering around the n=2 threshold have been investigated by using the R-matrix method with pseudostates. The elastic and excitation collision strengths show dramatic changes when the interaction screening length D varies from to 3.8 a.u., as a result of the convergence of 1,3S Feshbach resonances to the varying 2s threshold and of the transformation of 1,3P and 1D Feshbach resonances into shape-type resonances when they pass across the 2s and 2p threshold at certain critical value of D, respectively. The resonance parameters for a large number of D in the range D=-3.8 a.u. are presented. It is observed that the 1,3P and 1D resonance contributions to the elastic and excitation collision strengths decrease rapidly with decreasing D after the resonance passes the critical D value. The contribution of a 1Se Feshbach resonance to the elastic or excitation collision strength changes into a cusp after the resonance merges into its parent 2s state and immerses into the background with the further decrease of D. © 2010 The American Physical Society.

Wang T.,Hefei University of Technology
Plant signaling & behavior | Year: 2012

Radiation-induced bystander effects (RIBE) have been well demonstrated in whole organisms, as well as in single-cell culture models in vitro and multi-cellular tissues models in vitro, however, the underlying mechanisms remain unclear, including the temporal and spatial course of bystander signaling. The RIBE in vivo has been shown to exist in the model plant Arabidopsis thaliana (A. thaliana). Importantly, the unique plant grafting provides a delicate approach for studying the temporal and spatial course of bystander signaling in the context of whole plants. In our previous study, the time course of bystander signaling in plants has been well demonstrated using the root micro-grafting technique. In this study, we further investigated the temporal cooperation pattern of multiple bystander signals, the directionality of bystander signaling, and the effect of bystander tissues on the bystander signaling. The results showed that the bystander response could also be induced efficiently when the asynchronously generated bystander signals reached the bystander tissues in the same period, but not when they entered into the bystander tissues in an inversed sequence. The absence of bystander response in root-inversed grafting indicated that the bystander signaling along roots might be of directionality. The bystander signaling was shown to be independent of the bystander tissues.

Xu L.D.,CAS Institute of Computing Technology | Xu L.D.,Shanghai JiaoTong University | Xu L.D.,Hefei University of Technology | Xu L.D.,Old Dominion University | And 2 more authors.
IEEE Transactions on Industrial Informatics | Year: 2014

Internet of Things (IoT) has provided a promising opportunity to build powerful industrial systems and applications by leveraging the growing ubiquity of radio-frequency identification (RFID), and wireless, mobile, and sensor devices. A wide range of industrial IoT applications have been developed and deployed in recent years. In an effort to understand the development of IoT in industries, this paper reviews the current research of IoT, key enabling technologies, major IoT applications in industries, and identifies research trends and challenges. A main contribution of this review paper is that it summarizes the current state-of-the-art IoT in industries systematically. © 2005-2012 IEEE.

Tang X.,Tsinghua University | Wang Z.,Tsinghua University | Xu Z.,Hefei University of Technology | Ghassemlooy Z.,Northumbria University
Journal of Lightwave Technology | Year: 2014

This paper proposes and analyzes the performance of the multihop free-space optical (FSO) communication links using a heterodyne differential phase-shift keying modulation scheme operating over a turbulence induced fading channel. A novel statistical fading channel model for multihop FSO systems using channel-state-information-assisted and fixed-gain relays is developed incorporating the atmospheric turbulence, pointing errors, and path-loss effects. The closed-form expressions for the moment generating function, probability density function, and cumulative distribution function of the multihop FSO channel are derived using Meijer's G-function. They are then used to derive the fundamental limits of the outage probability and average symbol error rate. Results confirm the performance loss as a function of the number of hops. Effects of the turbulence strength varying from weak-to-moderate and moderate-to-strong turbulence, geometric loss, and pointing errors are studied. The pointing errors can be mitigated by widening the beam at the expense of the received power level, whereas narrowing the beam can reduce the geometric loss at the cost of increased misalignment effects. © 1983-2012 IEEE.

Bao H.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Zhang W.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Hua Q.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Jiang Z.,CAS Hefei Key Laboratory of Materials for Energy Conversion | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Crystal clear: Uniform Cu 2O nanooctahedra (o-Cu 2O) and nanocubes (c-Cu 2O) undergo surface restructuring during CO oxidation for the in-situ formation of catalytically active CuO thin films to give CuO/o-Cu 2O and CuO/c-Cu 2O, respectively (see picture). The structure and catalytic performance of CuO thin films are controlled by the crystal plane exposed on the underlying Cu 2O nanocrystals. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang B.-H.,Okayama University | Wu X.-P.,Hefei University of Technology
Chinese Physics B | Year: 2013

We have applied a thermodynamical model to calculate the diffusion coefficient of aluminum in MgO with the aid of bulk elastic properties. Our calculated diffusivities as a function of temperature and pressure are compared with the existing results derived from experimental or theoretical investigations. We find that the present model provides a satisfactory estimation for the activation volume and the activation enthalpy. © 2013 Chinese Physical Society and IOP Publishing Ltd.

Wang J.-Z.,Hefei University of Technology | Li H.-Z.,CAS Guangzhou Institute of Geochemistry | Li H.-Z.,University of Chinese Academy of Sciences | You J.,CAS Guangzhou Institute of Geochemistry
Environmental Pollution | Year: 2012

Current-use insecticides including organophosphate (OPs) and synthetic pyrethroid (SPs) insecticides were analyzed in 35 sediment samples collected from Chaohu Lake in China, where a transition from a traditional agricultural to a modern urbanized society is ongoing. Total concentrations of five OPs and eight SPs ranged from 0.029 to 0.681 ng/g dry weight and 0.016-301 ng/g dry weight, respectively. Toxic unit analysis showed that 13% of the sediment samples likely produced over 50% of the mortality for benthic invertebrates. Analysis also showed that cypermethrin was the principal contributor to the toxicity. Spatial distribution evaluation implied that OPs were mainly from non-point sources associated with agricultural activities. Conversely, SPs may have been derived from runoff of inflowing rivers through urban regions, as their concentrations were well-correlated with concentrations of other urban-oriented contaminants. © 2011 Elsevier Ltd. All rights reserved.

Li Z.,Shanghai JiaoTong University | Kang Y.,Hefei University of Technology
Automatica | Year: 2010

The hybrid joints can be switched to either active (actuated) or passive (under-actuated) mode as needed (Li, Ming, Xi, & Shimojo, 2006), in this paper, dynamic coupling switching control incorporating Support Vector Machines (SVMs) is developed for wheeled mobile manipulators with hybrid joints. The hybrid actuated robot dynamics is a mixed under-actuated and actuated model. In order to approximate the high dimension unmodelled dynamics, the SVMs matrix and its operator are proposed. Considering the joint switching as an event, the event driven switching control strategy is used to ensure that the system outputs track the given bounded reference signals within a small neighborhood of zero, and guarantee semi-global uniform boundedness of all closed loop signals, and the switch stability. The effectiveness of the proposed controls is verified through extensive simulations. © 2010 Elsevier Ltd. All rights reserved.

Zhou R.,University of Nebraska - Lincoln | Zhou R.,Hefei University of Technology | Zeng X.C.,University of Nebraska - Lincoln
Journal of the American Chemical Society | Year: 2012

It is well established that graphite can be transformed into superhard carbons under cold compression (Mao et al. Science2003, 302, 425). However, structure of the superhard carbon is yet to be determined experimentally. We have performed an extensive structural search for the high-pressure crystalline phases of carbon using the evolutionary algorithm. Nine low-energy polymorphic structures of sp 3-hybridized carbon result from the unbiased search. These new polymorphic carbon structures together with previously reported low-energy sp 3-hybridized carbon structures (e.g., M-carbon, W-carbon, and Cco-C 8 or Z-carbon) can be classified into three groups on the basis of different ways of stacking two (or more) out of five (A-E) types of buckled graphene layers. Such a classification scheme points out a simple way to construct a variety of sp 3-hybridized carbon allotropes via stacking buckled graphene layers in different combinations of the A-E types by design. Density-functional theory calculations indicate that, among the nine low-energy crystalline structures, seven are energetically more favorable than the previously reported most stable crystalline structure (i.e., Cco-C 8 or Z-carbon) in the pressure range 0-25 GPa. Moreover, several newly predicted polymorphic sp 3-hybridized carbon structures possess elastic moduli and hardness close to those of the cubic diamond. In particular, Z-carbon-4 possesses the highest hardness (93.4) among all the low-energy sp 3-hybridized carbon structures predicted today. The calculated electronic structures suggest that most polymorphic carbon structures are optically transparent. The simulated X-ray diffraction (XRD) spectra of a few polymorphic structures are in good agreement with the experimental spectrum, suggesting that samples from the cold-compressed graphite experiments may consist of multiple polymorphic phases of sp 3-hybridized carbon. © 2012 American Chemical Society.

Chen J.,Southwest University of Science and Technology | Hu J.,Hefei University of Technology
Journal of the Optical Society of America B: Optical Physics | Year: 2014

We have investigated the coupling behaviors between localized and propagating surface plasmon modes in a noncentrosymmetric structure consisting of an L-shaped metal nanoparticle array and a thick metal film, separated by a silica dielectric spacer layer. It is found that surface plasmon modes exhibit hybrid behaviors due to the noncentrosymmetry of the structure. The hybrid surface plasmon modes will interact with different-order localized plasmon modes in the nanoparticle in their spectrally overlapping regions. The strong coupling between the localized and propagating plasmon modes gives rise to the energy anticrossing behavior with large mode splitting. Furthermore, a narrow absorption branch is also observed between two anticrossing absorption branches, which is absent in the centrosymmetric system. The findings hold promise in applications such as photonic and energy conversion systems and the design of novel plasmonic nanodevices. © 2014 Optical Society of America.

Gupta A.K.,Indian Institute of Technology Ropar | Sharma S.,Hefei University of Technology | Redhu P.,Indian Institute of Technology Ropar
Communications in Theoretical Physics | Year: 2014

The optimal current difference lattice hydrodynamic model is extended to investigate the traffic flow dynamics on a unidirectional single lane gradient highway. The effect of slope on uphill/downhill highway is examined through linear stability analysis and shown that the slope significantly affects the stability region on the phase diagram. Using nonlinear stability analysis, the Burgers, Korteweg-deVries (KdV) and modified Korteweg-deVries (mKdV) equations are derived in stable, metastable and unstable region, respectively. The effect of reaction coefficient is examined and concluded that it plays an important role in suppressing the traffic jams on a gradient highway. The theoretical findings have been verified through numerical simulation which confirm that the slope on a gradient highway significantly influence the traffic dynamics and traffic jam can be suppressed efficiently by considering the optimal current difference effect in the new lattice model. © 2014 Chinese Physical Society and IOP Publishing Ltd.

Geng J.-B.,Hefei University of Technology | Geng J.-B.,CAS Institute of Policy and Management | Ji Q.,CAS Institute of Policy and Management
Energy | Year: 2014

China's energy supply security has faced many challenges such as the drastic change of the international energy environment and the domestic energy situation and so on. This paper constructs a multi-dimensional indicator system for the main risks deriving from four aspects to evaluate the situation of China's energy supply security and analyze its evolution characteristics from 1994 to 2011. The results indicate that the situation of China's energy supply security generally presented a downtrend during 1994-2008, as a result of increasing international energy market monopoly and high volatility of international crude oil prices. After 2008, the overall level of China's energy supply security has improved to the level of 2003, which is attributed to the relatively stable international energy environment as well as the effective implementation of energy policies. © 2013 Elsevier Ltd.

Shi L.,Hefei University of Technology | Pei C.,Chinese University of Hong Kong | Li Q.,Chinese University of Hong Kong
Nanoscale | Year: 2010

Well-aligned arrays of chalcopyrite CuInS2 one dimensional nanostructures have been prepared in a controllable manner via a convenient wet-chemical approach using anodic aluminium oxide (AAO) as a hard template. Highly oriented CuInS2 nanotubes, nano test tubes and nanowires arrays can be selectively grown by simply varying reaction conditions. Oleylamine (OLA) was found to play a key role in the synthesis and morphology control of the CuInS2 product. The structure, morphology, composition and optical absorption properties of the as-prepared samples were characterized using X-ray powder diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and UV-Vis spectrophotometry. The formation mechanism of the CuInS2 arrays is discussed. © The Royal Society of Chemistry 2010.

Li Y.-M.,Tsinghua University | Li Y.-M.,Hefei University of Technology | Li Y.-T.,Tsinghua University | Pan M.,Tsinghua University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2014

Sortase-mediated hydrazinolysis of proteins with hydrazine or its derivatives was developed for the production of recombinant protein hydrazides. This process provides an alternative approach for protein semisynthesis through the use of recombinant protein hydrazides as thioester surrogates. It also provides an alternative method for C-terminal modification of proteins with functional units as well as for the preparation of C-to-C fusion proteins. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Du H.,Nanjing Southeast University | Du H.,Hefei University of Technology | Li S.,Nanjing Southeast University | Ding S.,Jiangsu University
Asian Journal of Control | Year: 2013

In this paper, the consensus problem is investigated via bounded controls for the multi-agent systems with or without communication. Based on the nested saturation method, the saturated control laws are designed to solve the consensus problem. Under the designed saturated control laws, the transient performance of the closed-loop system can be improved by tuning the saturation level. First of all, asymptotical consensus algorithms with bounded control inputs are proposed for the multi-agent systems with or without communication delays. Under these consensus algorithms, the states' consensus can be achieved asymptotically. Then, based on a kind of novel nonlinear saturation functions, bounded finite-time consensus algorithms are further developed. It is shown that the states' consensus can be achieved in finite time. Finally, two examples are given to verify the efficiency of the proposed methods. © 2012 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.

Chin K.-S.,City University of Hong Kong | Fu C.,Hefei University of Technology | Fu C.,CAS Hefei Institutes of Physical Science
Expert Systems with Applications | Year: 2014

A combination of cardinal and ordinal preferences in multiple-attribute decision making (MADM) demonstrates more reliability and flexibility compared with sole cardinal or ordinal preferences derived from a decision maker. This situation occurs particularly when the knowledge and experience of the decision maker, as well as the data regarding specific alternatives on certain attributes, are insufficient or incomplete. This paper proposes an integrated evidential reasoning (IER) approach to analyze uncertain MADM problems in the presence of cardinal and ordinal preferences. The decision maker provides complete or incomplete cardinal and ordinal preferences of each alternative on each attribute. Ordinal preferences are expressed as unknown distributed assessment vectors and integrated with cardinal preferences to form aggregated preferences of alternatives. Three optimization models considering cardinal and ordinal preferences are constructed to determine the minimum and maximum minimal satisfaction of alternatives, simultaneous maximum minimal satisfaction of alternatives, and simultaneous minimum minimal satisfaction of alternatives. The minimax regret rule, the maximax rule, and the maximin rule are employed respectively in the three models to generate three kinds of value functions of alternatives, which are aggregated to find solutions. The attribute weights in the three models can be precise or imprecise (i.e., characterized by six types of constraints). The IER approach is used to select the optimum software for product lifecycle management of a famous Chinese automobile manufacturing enterprise. © 2014 Elsevier Ltd. All rights reserved.

Fan Y.,Anhui University | Feng G.,City University of Hong Kong | Wang Y.,Hefei University of Technology | Song C.,Nanjing University of Science and Technology
Automatica | Year: 2013

This paper studies the distributed rendezvous problem of multi-agent systems with novel event-triggered controllers. We have proposed a combinational measurement approach to event design and developed the basic event-triggered control algorithm. As a result, control of agents is only triggered at their own event time, which reduces the amount of communication and lowers the frequency of controller updates in practice. Furthermore, based on the convergence analysis of the basic algorithm, we have proposed a new iterative event-triggered algorithm where continuous measurement of the neighbor states is avoided. It is noted that the amount of communication among agents has been significantly reduced without obvious negative effects on the control performances. The effectiveness of the proposed strategies is illustrated by numerical examples in 3D spaces. © 2012 Elsevier Ltd. All rights reserved.

Zhang D.-W.,University of Hong Kong | Zhu S.-L.,Nanjing University | Zhu S.-L.,Hefei University of Technology | Wang Z.D.,University of Hong Kong
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

We propose a scheme to simulate and explore Weyl semimetal physics with ultracold fermionic atoms in a two-dimensional square optical lattice subjected to experimentally realizable spin-orbit coupling and an artificial dimension from an external parameter space, which may increase experimental feasibility compared with the cases in three-dimensional optical lattices. It is shown that this system with a tight-binding model is able to describe essentially three-dimensional Weyl semimetals with tunable Weyl points. The relevant topological properties are also addressed by means of the Chern number and the gapless edge states. Furthermore, we illustrate that the mimicked Weyl points can be experimentally detected by measuring the atomic transfer fractions in a Bloch-Zener oscillation, and the characteristic topological invariant can be measured with the particle pumping approach. © 2015 American Physical Society. ©2015 American Physical Society.

Chen Q.,Southwest Technique and Engineering Institute | Shu D.,Southwest Technique and Engineering Institute | Zhao Z.,Southwest Technique and Engineering Institute | Wang Y.,Southwest Technique and Engineering Institute | Yuan B.,Hefei University of Technology
Materials and Design | Year: 2012

The Mg-5.3. wt.%Zn-1.13. wt.%Nd-0.51. wt.%La-0.28. wt.%Pr-0.79. wt.%Zr alloy prepared by direct chill casting is subjected to hot extrusion. The effects of extrusion ratio and temperature on microstructure and tensile mechanical properties have been studied. The results indicate coarse grains of as-cast alloys are refined with extrusion ratio increasing from 0 to 9. The eutectic constituents are elongated along extrusion direction. However, further increase of extrusion ratio has a little influence on grain refinement and the improvement of mechanical properties of the alloy. Dynamic recrystallisation is the main mechanism of grain refinement during hot extrusion. Raising extrusion temperature results in grain coarsening. Grain shape becomes more equiaxed-like with raising extrusion temperature. At the same time, mechanical properties decrease with the increase of extrusion temperature. © 2012 Elsevier Ltd.

Ge C.,Chinese Academy of Sciences | Ge C.,Hefei University of Technology | Yu L.,Chinese Academy of Sciences | Fang Z.,Chinese Academy of Sciences | Zeng L.,Chinese Academy of Sciences
Analytical Chemistry | Year: 2013

Histone methylation is a crucial epigenetic modification of chromosomes. In this work, we describe an enhanced strip biosensor using oligonucleotide- functionalized gold nanoparticles as an enhancer probe (AuNP-DNA) for rapid and sensitive detection of histone methylation. In conventional strip biosensor, methylated histone is captured on the test zone through the formation of antibody/methylated histone/antibody-labeled AuNP sandwich structures. Whereas, in the enhanced strip biosensor, the AuNPs in the sandwich structures are dual labeled with an antibody and another oligonucleotide (c-DNA). The sequence of the c-DNA is complementary to the oligonucleotide on the enhancer probe. The enhancer probe, AuNP-DNA, hybridizes with the c-DNA on the dual labeled AuNPs, and the color intensity of the red band on the test zone is then enhanced dramatically. The enhanced strip biosensor has been used for the visual detection of trimethylated lysine 9 of histone H3 (H3K9me3) in 20 ng of histone extract from HeLa cells within 15 min. The detection limit is 10-fold and 15-fold lower than the conventional strip biosensor and Western blot, respectively. © 2013 American Chemical Society.

Wang M.,National University of Singapore | Wang M.,Hefei University of Technology | Ni B.,Advanced Digital science Center | Hua X.-S.,Microsoft | Chua T.-S.,National University of Singapore
ACM Computing Surveys | Year: 2012

Along with the explosive growth of multimedia data, automatic multimedia tagging has attracted great interest of various research communities, such as computer vision, multimedia, and information retrieval. However, despite the great progress achieved in the past two decades, automatic tagging technologies still can hardly achieve satisfactory performance on real-world multimedia data that vary widely in genre, quality, and content. Meanwhile, the power of human intelligence has been fully demonstrated in the Web 2.0 era. If well motivated, Internet users are able to tag a large amount of multimedia data. Therefore, a set of new techniques has been developed by combining humans and computers for more accurate and efficient multimedia tagging, such as batch tagging, active tagging, tag recommendation, and tag refinement. These techniques are able to accomplish multimedia tagging by jointly exploring humans and computers in different ways. This article refers to them collectively as assistive tagging and conducts a comprehensive survey of existing research efforts on this theme. We first introduce the status of automatic tagging and manual tagging and then state why assistive tagging can be a good solution. We categorize existing assistive tagging techniques into three paradigms: (1) tagging with data selection&organization; (2) tag recommendation; and (3) tag processing. We introduce the research efforts on each paradigm and summarize the methodologies. We also provide a discussion on several future trends in this research direction. © 2012 ACM.

Forrester P.J.,University of Melbourne | Liu D.-Z.,Hefei University of Technology | Liu D.-Z.,Chinese Academy of Sciences
Journal of Statistical Physics | Year: 2014

Recent works have shown that the family of probability distributions with moments given by the Fuss–Catalan numbers permit a simple parameterized form for their density. We extend this result to the Raney distribution which by definition has its moments given by a generalization of the Fuss–Catalan numbers. Such computations begin with an algebraic equation satisfied by the Stieltjes transform, which we show can be derived from the linear differential equation satisfied by the characteristic polynomial of random matrix realizations of the Raney distribution. For the Fuss–Catalan distribution, an equilibrium problem characterizing the density is identified. The Stieltjes transform for the limiting spectral density of the singular values squared of the matrix product formed from q inverse standard Gaussian matrices, and s standard Gaussian matrices, is shown to satisfy a variant of the algebraic equation relating to the Raney distribution. Supported on [0, ∞), we show that it too permits a simple functional form upon the introduction of an appropriate choice of parameterization. As an application, the leading asymptotic form of the density as the endpoints of the support are approached is computed, and is shown to have some universal features. © 2014, Springer Science+Business Media New York.

Wang M.,Hefei University of Technology | Gao Y.,National University of Singapore | Lu K.,University of Chinese Academy of Sciences | Rui Y.,Microsoft
IEEE Transactions on Image Processing | Year: 2013

In view-based 3D object retrieval and recognition, each object is described by multiple views. A central problem is how to estimate the distance between two objects. Most conventional methods integrate the distances of view pairs across two objects as an estimation of their distance. In this paper, we propose a discriminative probabilistic object modeling approach. It builds probabilistic models for each object based on the distribution of its views, and the distance between two objects is defined as the upper bound of the Kullback-Leibler divergence of the corresponding probabilistic models. 3D object retrieval and recognition is accomplished based on the distance measures. We first learn models for each object by the adaptation from a set of global models with a maximum likelihood principle. A further adaption step is then performed to enhance the discriminative ability of the models. We conduct experiments on the ETH 3D object dataset, the National Taiwan University 3D model dataset, and the Princeton Shape Benchmark. We compare our approach with different methods, and experimental results demonstrate the superiority of our approach. © 2012 IEEE.

Li P.,Shanghai University of Engineering Science | Lu D.,Hefei University of Technology
Journal of Applied Mechanics, Transactions ASME | Year: 2011

An analytical solution is derived for the time-dependent flow and deformation coupling of a saturated isotropic homogeneous incompressible poroelastic media within a two-dimensional (2D) finite domain due to a point source at some arbitrary position. In this study, the pore pressure field is assumed to conform to the second type of boundary conditions. Boundary conditions of the displacement field are chosen with care to match the appropriate finite sine and cosine transforms and simplify the resulting solution. It is found that the analytical solution is always independent of the Poisson's ratio. The detailed solutions are given for the case of a periodic point source with zero pressure derivatives on the boundaries and for an imposed pressure derivative on the lower edge in the absence of a source. The presented analytical solutions are highly applicable for calibrating numerical codes, and meanwhile they can be used to further investigate the transient behavior of flow and deformation coupling induced by fluid withdrawal within a 2D finite poroelastic media. © 2011 American Society of Mechanical Engineers.

Xu X.-X.,Jiangxi Normal University | Yuan H.-C.,Changzhou Institute of Technology | Fan H.-Y.,Hefei University of Technology
Journal of the Optical Society of America B: Optical Physics | Year: 2015

A scheme for conditional generating Hermite polynomial excited squeezed vacuum states (HPESVS) is proposed. Injecting a two-mode squeezed vacuum state (TMSVS) into a beam splitter (BS) and counting the photons in one of the output channels, the conditional state in the other output channel is just a HPESVS. To exhibit a number of nonclassical effects and non-Gaussianity, we mainly investigate the photon number distribution, sub-Poissonian distribution, quadrature component distribution, and Wigner function of the conditional HPESVS. We find that its nonclassicality closely relates to the control parameter of the BS, the squeezed parameter of TMSVS, and the photon number of conditional measurement. These further demonstrate that performing the conditional measurement on a BS is an effective approach to generate non-Gaussian state. © 2015 Optical Society of America.

Cai H.,Hefei University of Technology | Fu G.,Princeton Plasma Physics Laboratory
Nuclear Fusion | Year: 2015

An extended magnetohydrodynamic model including the effect of runaway current is developed and implemented in the M3D code. Based on this model, a simulation has been carried out to investigate the linear stability and the nonlinear evolution of the n = 1 resistive kink mode in the presence of runaway current. It is found that sawteeth oscillation is suppressed in a runaway plasma. The nonlinear evolution of the n = 1 mode only leads to a single sawtooth crash before reaching a new steady state axi-symmetric equilibrium with flattened current profile in the plasma core and q(0) > 1. © 2015 IAEA.

Li G.,CAS Hefei Institutes of Physical Science | Li G.,Hefei University of Technology
Nuclear Fusion | Year: 2015

The experimental results of ATC (Adiabatic Toroidal Compressor) are re-analysed with magnetic-compression theory for clarifying the inductance of compressed plasma. Its time-varying nature during compression is revealed, as there has been uncertainty since 1977 (Daughney et al 1977 Nucl. Fusion 17 2). During compression in the major radius, the plasma inductance decreases quasi-linearly with the major radius, and its magnetic energy increases quasi-linearly with the major radius. © 2015 IAEA, Vienna.

Jo S.B.,Pohang University of Science and Technology | Lee W.H.,Pohang University of Science and Technology | Qiu L.,Hefei University of Technology | Cho K.,Pohang University of Science and Technology
Journal of Materials Chemistry | Year: 2012

This article reviews the recent advances in organic electronics based on polymer blends with one-dimensional (1D) nanowires (NWs) of π-conjugated polymers. Self-assembled polymer semiconducting NWs are fascinating building blocks for their directional extension of inter- and intramolecular π-conjugation. This extensive conjugation provides unique electrical and optical properties that benefit applications in organic electronic devices. Outstanding performances are particularly expected from blending these NWs with insulating polymers or semiconducting molecules. Several representative reports describing NWs prepared from semiconducting/insulating polymer blends, conjugated block copolymers, or electrospinning for use as high-performance organic thin-film transistors (OTFTs) are discussed. The concepts of phase-separation behavior and the growth of crystalline NWs from multi-phase blend solutions are also illustrated. Research into the solubility-induced formation of NWs from semiconducting polymer/n-type small molecule blends for high-efficiency organic photovoltaic solar cells (OPVs) is introduced. In addition, the effects of the chemical properties of conjugated polymers on the optical and electrical properties of NWs and the use of ordered NW structures in OPVs are summarized. This critical review provides insights and a new perspective on the optimization of blend morphologies, which consequently enhances the performance of organic electronic devices. © 2012 The Royal Society of Chemistry.

Wang Z.-G.,North China Electrical Power University | Tian Y.-F.,Hefei University of Technology
International Journal of Modern Physics A | Year: 2015

In this paper, we tentatively assign the Y(4140), Y(4274) and X(4350) to be the scalar and tensor csc¯s¯ tetraquark states, respectively, and study them with the QCD sum rules. In the operator product expansion, we take into account the vacuum condensates up to dimension-10. In calculations, we use the formula μ = √M2 X/Y/Z- (2M{double-struck}c)2to determine the energy scales of the QCD spectral densities. The numerical results favor assigning the Y(4140) to be the JPC= 2++diquark-antidiquark type tetraquark state, and disfavor assigning the Y(4274) and X(4350) to be the 0++or 2++tetraquark states. © 2015 World Scientific Publishing Company.

Liu S.-H.,Hohai University | Gao J.-J.,Hohai University | Wang Y.-Q.,Hefei University of Technology | Weng L.-P.,Hohai University
Geotextiles and Geomembranes | Year: 2014

The effectiveness of soilbags in reducing mechanical vibration is investigated, and the influential factors are examined through a series of laboratory tests, including cyclic lateral shear tests, vertical excitation tests and small shaking table tests as well as a soilbag-filled trench field test. The test results illustrate that soilbags have a relatively high damping ratio and variable horizontal stiffness, which are greatly influenced by the materials inside the bags at low vertical stress but become nearly independent of the materials inside the bags at high vertical stress. We find that vertical and horizontal vibrations can be effectively reduced through the use of soilbags. © 2014 Elsevier Ltd.

Ni H.,Hefei University of Technology | Ni H.,University of Bayreuth | Hui H.,Nanjing University | Steinle-Neumann G.,University of Bayreuth
Reviews of Geophysics | Year: 2015

A quantitative description of the transport properties, diffusivity, viscosity, electrical, and thermal conductivity, of silicate melts is essential for understanding melting-related petrologic and geodynamic processes. We here provide a systematic overview on the current knowledge of these properties from experiments and molecular dynamics simulations, their dependence on pressure, temperature, and composition, atomistic processes underlying them, and physical models to describe their variations. We further establish phenomenological and physical links between diffusivity, viscosity, and electrical conductivity that are based on structural rearrangement in the melt. Neutral molecules and network-modifying cations with low electric field strength display intrinsic diffusivity, which is controlled by the intrinsic properties (size and valence) of the species. By contrast, oxygen and network formers with high field strength show extrinsic diffusivity, which is more sensitive to extrinsic parameters including temperature (T), pressure (P), and melt composition (X). Similar T-P-X dependence of diffusivity and electrical conductivity and their quantitative relation reveal the role of intrinsically diffusing species in electrical transport, while viscosity is tied to the extrinsically diffusing species in a similar way. However, the differences in the structural role and mobility of various atomic species diminish with increasing temperature and/or pressure: all transport processes are increasingly coupled, eventually converging to a uniform rate and mechanism. Accurate comprehension of interatomic interactions and melt structure is vital to fully accounting for the compositional dependence of transport properties, and simple polymerization parameters such as nonbridging oxygen per tetrahedrally coordinated cation are inadequate. © 2015. American Geophysical Union. All Rights Reserved.

Zhang H.,Hefei University of Technology
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2011

To obtain new fungi producing dextranase,we screened and identified a strain F1001 showing high dextranase activities. We provided a new strain with dextranase activity for producing clinical dextran. Morphological and ITS rDNA sequences homology analysis were performed to identify the strain F1001. The enzyme was purified to electrophoretic homogeneity by the steps of ammonium sulfate precipitation and Sepharose 6B column chromatography. We studied the catalytic properties and the mechanism of the dextranase, and activities of dextranase were measured with dextran 70 kDa as the substrate. The isolated strain F1001 was identifed as Penicillium aculeatum precisely by ITS rDNA sequences homology analysis. Its molecular mass was estimated to be about 66 kDa by SDS-PAGE. The optimal reaction temperature was 35 degrees C, and the optimum pH was 5.0, it was stable in the condition of pH 4.0 - 7.0 and under the temperature of 50 degrees C. The optimum substrate concentration was 3% (w/v). The final dextranase hydrolysis product was isomaltose, which proved that the enzyme was endodextranase and only had activity with dextran joined mainly by continual alpha, 1-6 glucosidic linkages. The K(m) for dextranase was calculated to be 3.55 x 10(-5) mol/L, and the V(max) was 4.29 x 10(-2) mol (Glu)/min x L. The enzyme activity was enhanced by Zn2+ and Cu2+, and the low concentration of Cu2+ could improve the dextranase activity to 134.7%. However, the enzyme was strongly inhibited by Mn2+. We isolated a new strain F1001 producing high dextranase activity and the enzyme was stable. These results may provide an important basis for industrial applications.

Liu Z.,Hefei University of Technology | Liu Z.,China Earthquake Administration | Huang J.,Beijing University of Technology | Peng Z.,Georgia Institute of Technology | Su J.,China Earthquake Administration
Geophysical Research Letters | Year: 2014

We investigate temporal changes of seismic velocity in the epicentral region of the 12 May 2008 Mw 7.9 Wenchuan earthquake using three-component continuous waveforms recorded by a seven-station small-aperture array. We use an ambient noise cross-correlation technique to compute the empirical Green's function between station pairs from August 2004 to September 2011. Our results show no obvious precursory change immediately before the main shock, clear coseismic reduction of seismic velocity of up to 0.2%, and initial postseismic recovery followed by a long-lived velocity reduction. The coseismic and postseismic velocity changes are most prominent in the period band of 2-4 s (approximate depth of 1-4 km), and the velocity changes are smaller in other period bands. The seismic velocity in the period band of 1-2 s (i.e., top 2 km) correlates well with the water level change of the Zipingpu Reservoir. The observed temporal changes likely reflect damage and healing processes with possible permanent deformation in the upper crust associated with the Wenchuan main shock. Key Points Clear coseismic velocity reduction during the Wenchuan main shock Initial postseismic recovery followed by a long-lived velocity reduction Negative correlation between velocity change and the Zipingpu water level ©2013. American Geophysical Union. All Rights Reserved.

Zhang L.L.,University of Texas at Austin | Zhao X.,University of Texas at Austin | Zhao X.,Donghua University | Stoller M.D.,University of Texas at Austin | And 8 more authors.
Nano Letters | Year: 2012

We present a novel method to prepare highly conductive, free-standing, and flexible porous carbon thin films by chemical activation of reduced graphene oxide paper. These flexible carbon thin films possess a very high specific surface area of 2400 m 2 g -1 with a high in-plane electrical conductivity of 5880 S m -1. This is the highest specific surface area for a free-standing carbon film reported to date. A two-electrode supercapacitor using these carbon films as electrodes demonstrated an excellent high-frequency response, an extremely low equivalent series resistance on the order of 0.1 ohm, and a high-power delivery of about 500 kW kg -1. While higher frequency and power values for graphene materials have been reported, these are the highest values achieved while simultaneously maintaining excellent specific capacitances and energy densities of 120 F g -1 and 26 W h kg -1, respectively. In addition, these free-standing thin films provide a route to simplify the electrode-manufacturing process by eliminating conducting additives and binders. The synthetic process is also compatible with existing industrial level KOH activation processes and roll-to-roll thin-film fabrication technologies. © 2012 American Chemical Society.

Yin J.,Hefei University of Technology | Hu J.,Anhui University of Science and Technology | Zhang G.,Anhui University of Science and Technology | Liu S.,Anhui University of Science and Technology
Langmuir | Year: 2014

A variety of slightly cross-linked poly(2-vinylpyridine)-poly(N- isopropylacrylamide) (P2VP-PNIPAM) core-shell microgels with pH- and temperature-responsive characteristic were prepared via seeded emulsion polymerization. Negatively charged sodium 2,6-naphthalenedisulfonate (2,6-NDS) could be internalized into the inner core, followed by formation of (P2VPH +/SO3 2-) supramolecular complex through the electrostatic attractive interaction in acid condition. The thermoresponsive characteristic feature of the (P2VPH+/SO3 2-)-PNIPAM core-shell microgels was investigated by laser light scattering and UV-vis measurement, revealing an integration of upper critical solution temperature (UCST) and lower critical solution temperature (LCST) behaviors in the temperature range of 20-55 °C. The UCST performance arised from the compromised electrostatic attractive interaction between P2VPH + and 2,6-NDS at elevated temperatures, while the subsequent LCST transition is correlated to the thermo-induced collapse of PNIPAM shells. The controlled release of 2,6-NDS was monitored by static fluorescence spectra as a function of temperature change. Moreover, stopped-flow equipped with a temperature-jump accessory was then employed to assess the dynamic process, suggesting a millisecond characteristic relaxation time of the 2,6-NDS diffusion process. Interestingly, the characteristic relaxation time is independent of the shell cross-link density, whereas it was significantly affected by shell thickness. We believe that these dual thermoresponsive core-shell microgels with thermotunable volume phase transition may augur promising applications in the fields of polymer science and materials, particularly for temperature-triggered release. © 2014 American Chemical Society.

Shi L.,Hefei University of Technology | Xu Y.,Chinese University of Hong Kong | Li Q.,Chinese University of Hong Kong
Nanoscale | Year: 2010

Highly oriented SnO2 nanotubes and nanowires arrays have been selectively fabricated via a convenient one-step wet-chemical approach using anodic aluminium oxide (AAO) as a hard template. Wall thickness of the SnO 2 nanotubes was tunable. The as-prepared nanostructures were composed of fine particles with sizes as small as 5 nm. Formation mechanism of SnO 2 nanostructure arrays with different shape is also discussed based on the experimental results. The structure, morphology, composition properties of the as-prepared samples were characterized using X-ray powder diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and Raman spectrum. © The Royal Society of Chemistry 2010.

Yao X.,Hefei University of Technology | Li D.,CAS Shanghai Institutes for Biological Sciences | Pei G.,CAS Shanghai Institutes for Biological Sciences
Nature Reviews Molecular Cell Biology | Year: 2013

An interactive, intellectual environment with good funding opportunities is essential for the development and success of basic research. The fast-growing economy and investment in science, together with a visionary plan, have attracted foreign scholars to work in China, motivated world-class Chinese scientists to return and strengthened the country's international collaborations. As a result, molecular and cell biology research in China has evolved rapidly over the past decade. © 2013 Macmillan Publishers Limited. All rights reserved.

Zhai J.,Nanjing Southeast University | Du H.,Nanjing Southeast University | Du H.,Hefei University of Technology
ISA Transactions | Year: 2013

This paper investigates the problem of semi-global stabilization by output feedback for a class of nonlinear systems using homogeneous domination approach. For each subsystem, we first design an output feedback stabilizer for the nominal system without the perturbing nonlinearities. Then, based on the ideas of the homogeneous systems theory and the adding a power integrator technique, a series of homogeneous output feedback stabilizers are constructed recursively for each subsystem and the closed-loop system is rendered semi-globally asymptotically stable. The efficiency of the output feedback stabilizers is demonstrated by a simulation example.

Xu H.-N.,Jiangnan University | Ma S.-F.,Jiangnan University | Chen W.,Hefei University of Technology
Soft Matter | Year: 2012

The effect of β-cyclodextrin (β-CD) on the aggregation behavior of a nonionic surfactant, Triton X-114 ((1,1,3,3-tetramethylbutyl)phenyl- polyethylene glycol), in aqueous solutions has been studied as a function of temperature by means of turbidity, dynamic light scattering (DLS), transmission electron microscopy (TEM), and rheo-small angle light scattering (rheo-SALS). The Triton X-114 (TX-114) solutions possess unique structural variations and display special aggregate transitions upon β-CD addition. In contrast to the reported aggregate disruption effect of β-CD for dilute nonionic surfactant solutions, aggregate growth is found in the aqueous TX-114 solutions of 93 mM upon β-CD addition. The micelle to vesicle transition induced by β-CD addition, which can greatly influence the turbidity and the viscosity of the solutions, is quantified by the characteristic length and aspect ratio of the aggregates. The characteristic length and aspect ratio of the aggregates change significantly after β-CD addition. It shows that aggregate growth may occur in nonionic surfactant-CD systems, as well as the reported ionic surfactant-CD systems. It is proposed that the CD-CD H-bonds create intermicelle interactions and promote aggregation of the CD/surfactant complexes, resulting in the formation of micrometer-scale phase-separated droplets. © 2012 The Royal Society of Chemistry.

Hu H.,Hefei University of Technology
IEEE Transactions on Information Theory | Year: 2014

We show that there is a very simple approach to determine the 2-adic complexity of periodic binary sequences with ideal two-level autocorrelation. This is the first main result by H. Xiong, L. Qu, and C. Li, IEEE Transactions on Information Theory, vol. 60, no. 4, pp. 2399-2406, Apr. 2014, and the main result by T. Tian and W. Qi, IEEE Transactions on Information Theory, vol. 56, no. 1, pp. 450-454, Jan. 2010. © 1963-2012 IEEE.

Song J.-M.,Anhui University | Zhang S.-S.,Anhui University | Yu S.-H.,Hefei University of Technology
Small | Year: 2014

A new kind of multifunctional Co0.85Se-Fe3O 4 nanocomposites is synthesized by loading Fe3O 4 nanoparticles (NPs) with a size of about 5 nm on the surface of Co0.85Se nanosheets under hydrothermal conditions without using any surfactant or structure-directing agents. The Co0.85Se-Fe 3O4 nanocomposite exhibits remarkable catalytic performance for hydrogenation of p-nitrophenol (4-NP) at room temperature and good adsorption behavior for methylene blue trihydrate in water. This nanocomposite also shows a high specific surface area and magnetic separation capability for recyclable utilization. The enhanced performances both in catalysis and adsorption are better than either individual component of Co 0.85Se nanosheets or Fe3O4 nanoparticles, demonstrating the possibility for designing new multifunctional nanocomposites with improved performances for catalysis, adsorbents, and other applications. Multifunctional Co0.85Se-Fe3O4 nanocomposites: A new kind of multifunctional nanocomposite is synthesized by loading Fe 3O4 nanoparticles (NPs) with a size of about 5 nm on the surface of Co0.85Se nanosheets under hydrothermal conditions without using any surfactant or structure-directing agents. These nanocomposites show efficient catalytic performance and stability for reduction of p-nitrophenol at room temperature and good adsorption behavior for methylene blue trihydrate in aqueous solution. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jin S.,Hefei University of Technology | Jin S.,University of Wyoming | Fallgren P.H.,Western Research Institute
Journal of Hazardous Materials | Year: 2010

Chlorinated compounds such as trichloroethene (TCE) are recalcitrant contaminants commonly detected in soil and groundwater. Contemporary remedies such as electron donor amendment tend to be less or ineffective in treating chlorinated compounds in matrix of lower permeability, such as clay. In this study, electrically induced reduction (EIR) was tested by inserting electrodes in saturated clay containing 122.49-125.43 mg TCE kg-1. Weak electric potentials (E) of 6, 9, and 12 V m-1 were applied, and up to 97% of TCE were depleted during the study period. Corresponding increases in chloride concentrations was observed during TCE depletion, indicating a reductive dechlorination pathway. No migration of TCE was observed between the two electrodes, neither were intermediate compounds such as dichloroethene (DCE) or vinyl chloride (VC). Results were also tested against a mathematical equation we previously established for field applications. Electrically induced reduction may offer a novel method for in situ degradation of chlorinated contaminants, especially in low-permeable media such as clay. © 2009 Elsevier B.V. All rights reserved.

Wang M.,Hefei University of Technology | Li H.,CAS Institute of Computing Technology | Tao D.,Intelligent Systems Technology, Inc. | Lu K.,University of Chinese Academy of Sciences | Wu X.,University of Vermont
IEEE Transactions on Image Processing | Year: 2012

This paper introduces a web image search reranking approach that explores multiple modalities in a graph-based learning scheme. Different from the conventional methods that usually adopt a single modality or integrate multiple modalities into a long feature vector, our approach can effectively integrate the learning of relevance scores, weights of modalities, and the distance metric and its scaling for each modality into a unified scheme. In this way, the effects of different modalities can be adaptively modulated and better reranking performance can be achieved. We conduct experiments on a large dataset that contains more than 1000 queries and 1 million images to evaluate our approach. Experimental results demonstrate that the proposed reranking approach is more robust than using each individual modality, and it also performs better than many existing methods. © 2012 IEEE.

Zhao W.,Hefei University of Technology
Research in Astronomy and Astrophysics | Year: 2014

Both the Wilkinson Microwave Anisotropy Probe (WMAP) and Planck missions have reported an extremely cold spot (CS) centered at Galactic coordinate (l = 209°, b = -57°) in the cosmic microwave background map. We study the local non-Gaussianity of the CS by defining local Minkowski functionals. We find that the third Minkowski functional ν2 is quite sensitive to the non-Gaussianity caused by the CS. Compared with random Gaussian simulations, the WMAP CS deviates from Gaussianity at more than a 99% confidence level with a scale of R ∼ 10°. Meanwhile, we find that cosmic texture provides an excellent explanation for these anomalies related to the WMAP CS, which could be further tested by future polarization data. © 2014 National Astronomical Observatories of Chinese Academy of Sciences and IOP Publishing Ltd.

Chen X.,Hefei University of Technology
Proceedings - 2011 4th International Symposium on Computational Intelligence and Design, ISCID 2011 | Year: 2011

The Capacitated Arc Routing Problem (CARP) has attracted much attention during the last few years due to its wide applications in real life. A Memetic Algorithm with Extended Neighborhood Search (MAENS) was developed for solving this kind of problem. A powerful local search operator, the so-called MS operator, was introduced and plays an important role in MAENS. But the main disadvantage is the high computational cost due to the large enumerative number of selecting route groups. In this paper, we propose an improved approach for MAENS with a divide-and-conquer strategy, named MAENS+, which divides a large graph into small sub graphs in order to decrease enumerative number so as to reduce the computational cost. An adaptive method is used for choosing parameters during dividing. Experimental results show that MAENS+ manages to obtain the same level of solution quality as MAENS with much less computational time. © 2011 IEEE.

Popov A.A.,Leibniz Institute for Solid State and Materials Research | Yang S.,Hefei University of Technology | Dunsch L.,Leibniz Institute for Solid State and Materials Research
Chemical Reviews | Year: 2013

One of the attractive properties of the hollow carbon clusters, known as fullerenes, is the possibility to use them as robust containers for other species. The field of chemical derivatization of EMFs has flourished in the past decade. Many cyclo- as well as radical addition reactions of EMFs are described forming a basis for the targeted synthesis of EMF-based functional materials. The a plications for EMFs as MRI contrasting agents and as electron-accepting blocks in photovoltaic devices are now considered as the most promising. Importantly, the reactivity and addition patterns of EMFs are significantly different from those of empty fullerenes. Advanced synthetic approaches and the progress in separation techniques dramatically improved the situation with availability of the EMF samples, which resulted in more dedicated and detailed studies of their structural, electronic, physical, and chemical properties. In the 1990s the field of the EMFs remained in the shadow of the empty fullerenes, which often resulted in the blind transfer of the guidelines, structural and chemical properties revealed for the empty fullerenes onto EMFs.

Li J.,Anhui Science and Technology University | Chen W.,Hefei University of Technology
Nongye Jixie Xuebao/Transactions of the Chinese Society of Agricultural Machinery | Year: 2012

In order to obtain better robustness and real-time processing of path recognition, the binary segmentation image, noise searching and filtering procedures were employed. The whole path was classified into far part and near part, and the difference between the two parts was used as a threshold for selecting target road. So the navigating parameters were adapted to the changing path. Based on a model of four-wheel intelligent vehicle, a path tracking simulation was performed. Then, the navigation system based on path tracking was designed by using two digital signal processors. The experiments showed the accuracy and robustness of the system.

Zhu H.,Brown University | Zhang S.,Brown University | Huang Y.-X.,Brown University | Huang Y.-X.,Hefei University of Technology | And 2 more authors.
Nano Letters | Year: 2013

Sub-10 nm nanoparticles (NPs) of M(II)-substituted magnetite M xFe3-xO4 (MxFe 1-xO•Fe2O3) (M = Mn, Fe, Co, Cu) were synthesized and studied as electrocatalysts for oxygen reduction reaction (ORR) in 0.1 M KOH solution. Loaded on commercial carbon support, these M xFe3-xO4 NPs showed the M(II)-dependent ORR catalytic activities with MnxFe3-xO4 being the most active followed by CoxFe3-xO4, Cu xFe3-xO4, and Fe3O4. The ORR activity of the MnxFe3-xO4 was further tuned by controlling x and MnFe2O4 NPs were found to be as efficient as the commercial Pt in catalyzing ORR. The MnFe2O 4 NPs represent a new class of highly efficient non-Pt catalyst for ORR in alkaline media. © 2013 American Chemical Society.

Wang L.,University of Texas at Austin | Lu Y.,University of Texas at Austin | Liu J.,State University of New York at Stony Brook | Xu M.,University of Texas at Austin | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2013

Sodium manganese hexacyanoferrates (NMHFCs) synthesized in aqueous solution at room temperature show high reversible capacity and outstanding rate capability as cathodes for a rechargeable sodium-ion battery (SIB). Earth-abundant elements and a low-cost synthesis route make these NMHFCs promising cathodes for SIBs, independent of natural lithium sources. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cao X.,City University of Hong Kong | Yang F.,Hefei University of Technology
Enterprise Information Systems | Year: 2011

In exploring the business operation of Internet companies, few researchers have used data envelopment analysis (DEA) to evaluate their performance. Since the Internet companies have a two-stage production process: marketability and profitability, this study employs a relational two-stage DEA model to assess the efficiency of the 40 dot com firms. The results show that our model performs better in measuring efficiency, and is able to discriminate the causes of inefficiency, thus helping business management to be more effective through providing more guidance to business performance improvement. © 2011 Taylor & Francis.

Yang G.,Hunan City University | Wu Y.,Tufts University | Xu X.,Hefei University of Technology
International Journal of Digital Content Technology and its Applications | Year: 2011

Manifold alignment is an important technique in finding the correspondence between two high-dimensional data sets. The algorithm of affine alignment of manifold is proposed in this paper. The benefits of our method is three-fold: First, the embedded manifolds are recovered and aligned simultaneously. Second, it can produce a linear mapping during the training step, which can be used to project the new test point easily. Three, spectral regression is used to reduce the complexity of the computation for retaining the linear projection. The effectiveness of our method is validated in the experiments.

Hu Z.,Hefei University of Technology | Hu Z.,Harvard University | Hu Z.,Columbia University | Van Rooijen N.,VU University Amsterdam | And 2 more authors.
Blood | Year: 2011

An animal model supporting human erythropoiesis will be highly valuable for assessing the biologic function of human RBCs under physiologic and disease settings, and for evaluating protocols of in vitro RBC differentiation. Herein, we analyzed human RBC reconstitution in NOD/ SCID or NOD/SCID/γc -/- mice that were transplanted with human CD34 + fetal liver cells and fetal thymic tissue. Although a large number of human CD45 -CD71 +nucleated immature erythroid cells were detected in the bone marrow, human RBCs were undetectable in the blood of these mice. Human RBCs became detectable in blood after macrophage depletion but disappeared again after withdrawal of treatment. Furthermore, treatment with human erythropoietin and IL-3 significantly increased human RBC reconstitution in macrophage-depleted, but not control, humanized mice. Significantly more rapid rejection of human RBCs than CD47- deficient mouse RBCs indicates that mechanisms other than insufficient CD47- SIRPα signaling are involved in human RBC xenorejection in mice. All considered, our data demonstrate that human RBCs are highly susceptible to rejection by macrophages in immunodeficient mice. Thus, strategies for preventing human RBC rejection by macrophages are required for using immunodeficient mice as an in vivo model to study human erythropoiesis and RBC function. © 2011 by The American Society of Hematology.

Swiatczak B.,Hefei University of Technology
Journal of the History of Biology | Year: 2014

It has long been taken for granted that the immune system's capacity to protect an individual from infection and disease depends on the power of the system to distinguish between self and nonself. However, accumulating data have undermined this fundamental concept. Evidence against the self/nonself discrimination model left researchers in need of a new overarching framework able to capture the immune system's reactivity. Here, I highlight that along with the self/nonself model, another powerful representation of the immune system's reactivity has been developed in the twentieth century immunology. According to this alternative view, the immune system is not a killer of nonself strangers but a peace-maker helping to establish harmony with the environment. The balance view of the system has never become part of the dominant paradigm. However, it is gaining more and more currency as new research develops. Advances in mucosal immunology confirm that instead of distinguishing between self and foreign the immune system reacts to microbial, chemical and self-induced alterations to produce responses that counterbalance effects of these changes. © 2013 Springer Science+Business Media Dordrecht.

Bai X.-X.,Hefei University of Technology | Wereley N.M.,University of Maryland University College
Journal of Applied Physics | Year: 2014

Magnetorheological (MR) energy absorbers (EAs) are an effective adaptive EA technology with which to maximize shock and vibration isolation. However, to realize maximum performance of the semi-active control system, the off-state (i.e., field off) stroking load of the MREA must be minimized at all speeds, and the dynamic range of the MREA must be maximized at high speed. This study presents a fail-safe MREA (MREA-FS) concept that, can produce a greater dynamic range at all piston speeds. A bias damping force is generated in the MREA-FS using permanent magnetic fields, which enables fail-safe behavior in the case of power failure. To investigate the feasibility and capability of the MREA-FS in the context of the semi-active control systems, a single-degree-of-freedom base excited rigid payload is mathematically constructed and simulated with skyhook control. © 2014 AIP Publishing LLC.

Wang S.,Hefei University of Technology
Physics of Plasmas | Year: 2016

For a plasma in a stationary homogeneous turbulence, the Fokker-Planck equation is derived from the nonlinear Vlasov equation by introducing the entropy principle. The ensemble average in evaluating the kinetic diffusion tensor, whose symmetry has been proved, can be computed in a straightforward way when the fluctuating particle trajectories are provided. As an application, it has been shown that a mean parallel electric filed can drive a particle flux through the Stokes-Einstein relation, independent of the details of the fluctuations. © 2016 AIP Publishing LLC.

Lan Y.,University of Houston | Lu Y.,U.S. Air force | Lu Y.,Hefei University of Technology | Ren Z.,University of Houston
Nano Energy | Year: 2013

Titanium dioxide is a wide band-gap semiconductor that can be excited to produce electron-hole pairs when irradiated with light. Such photo-induced electron-hole pairs have been utilized to generate electricity in solar cells, to split water into hydrogen and oxygen, to oxidize and degrade inorganic/organic/biological compounds in environments as well as to create superhydrophilicity. The wide solar applications and mechanisms of these photo-induced reactions are briefly reviewed in this mini review. This review would assist the readers to obtain an overview of this exciting and promising field. © 2013 Elsevier Ltd.

Liu H.,East China Normal University | Gu Z.,Hefei University of Technology | Jiang X.,East China Normal University
Advanced Synthesis and Catalysis | Year: 2013

Trifluoromethylation meets C-H activation: after transition metal-catalyzed trifluoromethylation became more and more popular, trifluoromethylation via C-H activation is now emerging as the latest attraction. Several pioneering examples and their mechanisms are discussed in this review. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Lan X.,Kings College | Lan X.,Hefei University of Technology | Masala S.,Kings College | Masala S.,King Abdullah University of Science and Technology | Sargent E.H.,Kings College
Nature Materials | Year: 2014

The solar-power conversion efficiencies of colloidal quantum dot solar cells have advanced from sub-1% reported in 2005 to a record value of 8.5% in 2013. Much focus has deservedly been placed on densifying, passivating and crosslinking the colloidal quantum dot solid. Here we review progress in improving charge extraction, achieved by engineering the composition and structure of the electrode materials that contact the colloidal quantum dot film. New classes of structured electrodes have been developed and integrated to form bulk heterojunction devices that enhance photocharge extraction. Control over band offsets, doping and interfacial trap state densities have been essential for achieving improved electrical communication with colloidal quantum dot solids. Quantum junction devices that not only tune the optical absorption spectrum, but also provide inherently matched bands across the interface between p-and n-materials, have proven that charge separation can occur efficiently across an all-quantum-tuned rectifying junction. © 2014 Macmillan Publishers Limited.

Interactions at plate boundaries induce stresses that constitute critical controls on the structural evolution of intraplate regions. However, the traditional tectonic model for the East Asian margin during the Mesozoic, invoking successive episodes of paleo-Pacific oceanic subduction, does not provide an adequate context for important Late Cretaceous dynamics across East Asia, including: continental-scale orogenic processes, significant sinistral strike-slip faulting, and several others. The integration of numerous documented field relations requires a new tectonic model, as proposed here. The Okhotomorsk continental block, currently residing below the Okhotsk Sea in Northeast Asia, was located in the interior of the Izanagi Plate before the Late Cretaceous. It moved northwestward with the Izanagi Plate and collided with the South China Block at about 100. Ma. The indentation of the Okhotomorsk Block within East Asia resulted in the formation of a sinistral strike-slip fault system in South China, formation of a dextral strike-slip fault system in North China, and regional northwest-southeast shortening and orogenic uplift in East Asia. Northeast-striking mountain belts over 500. km wide extended from Southeast China to Southwest Japan and South Korea. The peak metamorphism at about 89. Ma of the Sanbagawa high-pressure metamorphic belt in Southwest Japan was probably related to the continental subduction of the Okhotomorsk Block beneath the East Asian margin. Subsequently, the north-northwestward change of motion direction of the Izanagi Plate led to the northward movement of the Okhotomorsk Block along the East Asian margin, forming a significant sinistral continental transform boundary similar to the San Andreas fault system in California. Sanbagawa metamorphic rocks in Southwest Japan were rapidly exhumed through the several-kilometer wide ductile shear zone at the lower crust and upper mantle level. Accretionary complexes successively accumulated along the East Asian margin during the Jurassic-Early Cretaceous were subdivided into narrow and subparallel belts by the upper crustal strike-slip fault system. The departure of the Okhotomorsk Block from the northeast-striking Asian margin resulted in the occurrence of an extensional setting and formation of a wide magmatic belt to the west of the margin. In the Campanian, the block collided with the Siberian margin, in Northeast Asia. At about 77. Ma, a new oceanic subduction occurred to the south of the Okhotomorsk Block, ending its long-distance northward motion. Based on the new tectonic model, the abundant Late Archean to Early Proterozoic detrital zircons in the Cretaceous sandstones in Kamchatka, Southwest Japan, and Taiwan are interpreted to have been sourced from the Okhotomorsk Block basement which possibly formed during the Late Archean and Early Proterozoic. The new model suggests a rapidly northward-moving Okhotomorsk Block at an average speed of 22.5. cm/yr during 89-77. Ma. It is hypothesized that the Okhotomorsk-East Asia collision during 100-89. Ma slowed down the northwestward motion of the Izanagi Plate, while slab pull forces produced from the subducting Izanagi Plate beneath the Siberian margin redirected the plate from northwestward to north-northwestward motion at about 90-89. Ma. © 2013 Elsevier B.V.

Zhao L.-C.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Zhao L.-C.,Hefei University of Technology | Liu J.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Liu J.,Beijing University of Technology
Journal of the Optical Society of America B: Optical Physics | Year: 2012

We find that diverse nonlinear waves, such as soliton, Akhmediev breather, and rogue waves (RWs), can emerge and interplay with each other in a two-mode coupled system. It provides a good platform to study interaction between different kinds of nonlinear waves. In particular, we obtain dark RWs analytically for the first time in the coupled system, and find that two RWs can appear in the temporal-spatial distribution. Possible ways to observe these nonlinear waves are discussed. © 2012 Optical Society of America.

Wang S.,Hefei University of Technology
Physics of Plasmas | Year: 2012

Nonlinear gyrokinetic equation is formulated in the Fokker-Planck form that puts the effects of the turbulent wave scattering into the divergence of a diffusive-convective flux in the phase space, unified with the binary collision operator. The macroscopic transport fluxes of the particle and heat transport due to the gyrokinetic turbulence are systematically derived, with the diffusive and convective fluxes and the nonlinear turbulence heating rate identified. The proposed theory includes the ponderomotive effects on the turbulent convection and heating, which were not included in the previous quasilinear theory. © 2012 American Institute of Physics.

Cai H.,Hefei University of Technology | Fu G.,Princeton Plasma Physics Laboratory
Physics of Plasmas | Year: 2012

The effects of energetic ions on stability of tearing mode are investigated by global kinetic/MHD hybrid simulations in a low beta tokamak plasma. The kinetic effects of counter circulating energetic ions from the non-adiabatic response are found to be strongly destabilizing while the effects from the adiabatic response are stabilizing. The net effect with both adiabatic and non-adiabatic contributions is destabilizing. On the other hand, the kinetic effects of co-circulating energetic ions from the non-adiabatic response are calculated to be weakly stabilizing while the corresponding adiabatic contribution is destabilizing for small energetic ion beta. The net effect is weakly stabilizing. The dependence of kinetic effects on energetic ion beta, gyroradius, and speed is studied systematically and the results agree in large part with the previous analytic results for the kinetic effects of circulating particles. For trapped energetic ions, their effects on tearing mode stability are dominated by the adiabatic response due to large banana orbit width and strong poloidal variation of particle pressure. The net effect of trapped energetic particles on tearing modes is much more destabilizing as compared to that of counter circulating particles at the same beta value. © 2012 American Institute of Physics.

Ren H.,Hefei University of Technology
Physics of Plasmas | Year: 2012

Theoretical research on the geodesic acoustic mode (GAM) induced by equilibrium toroidal rotation flow in the tokamak plasmas is approached by using ideal magnetohydrodynamic model. The dispersion relation of the GAM is presented by taking into account magnetic field perturbations. It is shown that β can decrease the frequency of the GAM. © 2012 American Institute of Physics.

Yuan W.,CAS Institute of Atmospheric Physics | Yu R.,Chinese Academy of Meteorological Sciences | Zhang M.,State University of New York at Stony Brook | Lin W.,Brookhaven National Laboratory | And 2 more authors.
Journal of Climate | Year: 2013

The simulations of summertime diurnal cycle of precipitation and low-level winds by the Community Atmosphere Model, version 5, are evaluated over subtropical East Asia. The evaluation reveals the physical cause of the observed diurnal rainfall variation in East Asia and points to the source of model strengths and weaknesses. Two model versions with horizontal resolutions of 2.88 and 0.58 are used. The models can reproduce the diurnal phase of large-scale winds over East Asia, with an enhanced lowlevel southwesterly in early morning. Correspondingly, models successfully simulated the diurnal variation of stratiform rainfall with a maximum in early morning. However, the simulated convective rainfall occurs at local noontime, earlier than observations and with larger amplitude (normalized by the daily mean). As a result, models simulated a weaker diurnal cycle in total rainfall over the western plain of China due to an out-of-phase cancellation between convective and stratiform rainfalls and a noontime maximum of total rainfall over the eastern plain of China. Over the East China Sea, models simulated the early-morning maximum of convective precipitation and, together with the correct phase of the stratiform rainfall, they captured the diurnal cycle of total precipitation. The superposition of the stratiform and convective rainfalls also explains the observed diurnal cycle in total rainfall in East Asia. Relative to the coarse-resolution model, the high-resolution model simulated slight improvement in diurnal rainfall amplitudes, due to the larger amplitude of stratiform rainfall. The two models, however, suffer from the same major biases in rainfall diurnal cycles due to the convection parameterization. © 2013 American Meteorological Society.

Cai W.,Chinese Academy of Sciences | Tang X.,Chinese Academy of Sciences | Tang X.,Hefei University of Technology | Sun B.,Chinese Academy of Sciences | Yang L.,Chinese Academy of Sciences
Nanoscale | Year: 2014

In this study, multifunctional Fe3O4/C/Au nanoparticles (NPs), which catalytically integrated active small Au NPs with surface-enhanced Raman scattering (SERS) active large Au NPs, were fabricated via a facile method and employed for the in situ SERS monitoring of a catalytic reaction of p-nitrothiophenol (p-NTP) to p-aminothiophenol (p-ATP). In addition, the effect of magnet power was tested and it was demonstrated that the SERS intensity of the reaction system was stronger, and the reaction proceeded more smoothly because more hot spots existed and remained the same in the magnetic field; hence, the catalytic rate could be determined. © 2014 the Partner Organisations.

Ren T.-T.,University of Hong Kong | Yu H.-Q.,Hefei University of Technology | Li X.-Y.,University of Hong Kong
Applied Microbiology and Biotechnology | Year: 2010

Quorum sensing (QS) through signal chemical molecules is known to be essential to bacterial adhesion and biofilm formation. In this study, the QS ability of aerobic granules-a special form of biofilms used for biological wastewater treatment-was investigated and compared with that of conventional activated sludge flocs. A novel sectional membrane bioreactor was used together with a flow-cell to evaluate the possible influence of signal chemicals produced by the source sludge on the growth mode of bacterial cells. The results demonstrate the apparent production of QS chemicals from granules and its impact on initial cell attachment and granule formation. When granules were used as the signal-producing biomass, the attached-growth mode was dominant for the free cells, and the biofilm formation rate in the flow-cell was about ten times faster than in cases which used activated sludge as the signal source biomass. In addition, the intracellular extract from mature granules significantly accelerated the sludge granulation process. It is argued that the production and expression of QS signal chemicals from granules and granule precursors might have induced the gene expression of bacteria in suspension for attached growth rather than suspended growth, leading to granule formation and its stable structure. © Springer-Verlag 2010.

Tan P.,Chinese University of Hong Kong | Xu N.,Hefei University of Technology | Schofield A.B.,University of Edinburgh | Xu L.,Chinese University of Hong Kong
Physical Review Letters | Year: 2012

In disordered colloidal systems, we experimentally measure the normal modes with the covariance matrix method and clarify the origin of low-frequency quasilocalization at the single-particle level. We observe important features from both jamming and glass simulations: There is a plateau in the density of states [D(ω)] which is suppressed upon compression, as predicted by jamming; within the same systems, we also find that the low-frequency quasilocalization originates from the large vibrations of defective structures coupled with transverse excitations, consistent with a recent glass simulation. The coexistence of these features demonstrates an experimental link between jamming and glass. Extensive simulations further show that such a structural origin of quasilocalization is universally valid for various temperatures and volume fractions. © 2012 American Physical Society.

Wang S.,University of Manchester | Pei B.,Hefei University of Technology | Zhao X.,University of Texas at Austin | Dryfe R.A.W.,University of Manchester
Nano Energy | Year: 2013

We successfully prepared a highly porous graphene on carbon cloth (PG/CC) via an electrophoretic deposition process. With this process, in order to obtain high porous graphene on carbon cloth, fine-size graphene should be used. When large-size graphene was used, carbon cloth was only covered by graphene (G/CC) without porous surface. PG/CC was used as electrodes for Flexible All-Solid-State Supercapacitors (FASSSs). The porous structure of PG/CC electrode significantly increased the surface area of graphene and thus the specific capacitance (79.19Fg-1 for PG/CC and 32.35Fg-1 for G/CC). The macroscopic porous morphology of carbon cloth as the electrode matrix enhanced the integration between electrode and electrolyte, which is favorable for the ion diffusion and electron transport. The excellent mechanical stability and flexibility of PG/CC ensures the device with good flexibility. The resultant PG/CC based FASSSs showed high specific capacitance, good cycling stability, and enhanced energy density and power density. © 2013 Elsevier Ltd.

Fan Y.,City University of Hong Kong | Feng G.,City University of Hong Kong | Wang Y.,Hefei University of Technology
Asian Journal of Control | Year: 2011

In this paper, we present a novel rendezvous algorithm framework - the combination framework, which is named after the term convex combination in computational geometry. The convergence of the proposed algorithms is proved based on the novel tools from the recent results in graph theory and consensus study. It has been observed that the circumcenter algorithm can be considered as a special case of the combination framework. Moreover, the relevant analysis provides us a novel viewpoint on designing and the rendezvous rate of rendezvous algorithms for networked multi-agent systems with limited sensing ranges. © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society.

Hu B.,Tongji University | Wang J.-G.,Hefei University of Technology | Li G.-Q.,Tongji University
Construction and Building Materials | Year: 2011

Two finite element models are proposed to simulate the behavior of eccentrically loaded FRP-wrapped RC columns. Comparison between numerical and experimental results indicates that perfect bond can be used to simulate the interfaces between concrete and FRP as well as interface elements. The developing curves of lateral displacement are similar to sine half-wave curves. Twenty specimens were tested based on the finite element model using perfect bond between concrete and FRP composites. The result shows the maximum concrete compressive stress does not change with various parameters and the maximum concrete compressive strain is inversely proportional to eccentricity-to-section height ratio and length-to-section height ratio. An analysis-oriented model and a design-oriented model are proposed to predict the strength. © 2010 Elsevier Ltd. All rights reserved.

Fu L.,Max Planck Institute for Solid State Research | Tang K.,Max Planck Institute for Solid State Research | Tang K.,China National Institute of Clean and Low Carbon Energy | Song K.,Max Planck Institute for Intelligent Systems (Stuttgart) | And 4 more authors.
Nanoscale | Year: 2014

Nitrogen-doped activated porous carbon fibres (ACFs) were prepared as anode materials for Na-ion batteries. They exhibit excellent electrochemical performance, especially rate performance. The excellent rate performance is ascribed to the fibre-like morphology and the facilitated charge transfer. The influence of nitrogen functionalities on charge transfer and electrochemical performance of N-doped carbon anodes for Na ion batteries is discussed. © 2013 The Royal Society of Chemistry.

Ge J.,CAS Suzhou Institute of Nano Technology and Nano Bionics | Cheng G.,Hefei University of Technology | Chen L.,CAS Suzhou Institute of Nano Technology and Nano Bionics
Nanoscale | Year: 2011

Large-scale transparent and flexible electronic devices have been pursued for potential applications such as those in touch sensors and display technologies. These applications require that the power source of these devices must also comply with transparent and flexible features. Here we present transparent and flexible supercapacitors assembled from polyaniline (PANI)/single-walled carbon nanotube (SWNT) composite thin film electrodes. The ultrathin, optically homogeneous and transparent, electrically conducting films of the PANI/SWNT composite show a large specific capacitance due to combined double-layer capacitance and pseudo-capacitance mechanisms. A supercapacitor assembled using electrodes with a SWNT density of 10.0 g cm-2 and 59 wt% PANI gives a specific capacitance of 55.0 F g-1 at a current density of 2.6 A g-1, showing its possibility for transparent and flexible energy storage. © 2011 The Royal Society of Chemistry.

Gao H.-Y.,Hefei University of Technology
Journal of Networks | Year: 2013

For the microelectronics manufacturing industries that have uncertain demand, high volume cost and Oligarchs characteristics, we often discuss the possibility of competitors on the capacity of strategy. First of all we use the industry data to analysis the manufacturing cost, demand and the historical situation of the revenue and we also discuss the influence about the uncertain demand and high volume cost to the industrial structure. Secondly, it put the individual manufacturer not considering the capacity decision of the competitor as the premise and put revenue as the performance target for capacity expansion to construct the mathematical optimization model of the productivity level under the uncertain demand. And the productivity level is called the micro capacity. The manufacturer based on competition and the levels of microscopic production can consider using the radical strategy or still upholding the microscopic optimal capacity, and then put forward a game model to analysis the expected profits of the leaders and the followers who have take the two strategies. Besides, we can use the industrial data to calculate and then get the equilibrium. At last we can calculate the conclusion that for the manufacturers of monopoly industry when they faced with the different marginal profit, different demand variation and hyperbaric capacity amortization cost, the leading manufacturers can use radical production strategy. On the one hand, they can improve the profits, on the other hand they can also compress the profit that was gotten by following the manufacturers. Therefore, the capacity expansion decision can be used as the means of competition for the leading manufacturers. © 2013 ACADEMY PUBLISHER.

Shi L.,Hefei University of Technology | Lin H.,Zhongkai University of Agriculture and Engineering
Langmuir | Year: 2011

SnO2 nanotubes have been prepared via a facile hydrothermal method at low temperatures using polycarbonate (PC) membrane as a hard template. The walls of as-prepared SnO2 nanotubes are composed of fine nanocrysalline particles and the size of SnO2 nanocrystals could be modified by changing reaction temperature. Formation mechanism of SnO 2 nanotubes is also discussed according to the experimental results. Cathodoluminescence properties of the SnO2 product indicated that the band gap of the nanostructures increase from 3.75 eV with a particle size 5.6 nm to 3.99 eV with a particle size 3.3 nm. The as-prepared SnO2 nanotubes were found to show enhanced gas-sensing activity and may be used as a candidate for the fabrication of gas sensors. © 2011 American Chemical Society.

High-resolution lithospheric structure is essential for understanding the tectonic evolution and deformation patterns of the southeastern Tibetan plateau. This is now possible due to recent advances in ambient noise and earthquake surface wave tomography, and great improvements in data coverage from dense portable array stations deployed in SE Tibet. In this review paper, I first give a brief overview of the tomographic methods from ambient noise and earthquake surface waves, and then summarize the major findings about the lithospheric structure and deformation in SE Tibet revealed by ambient noise and earthquake surface wave tomography as well as by other seismic and geophysical observations. These findings mainly include the 3-D distribution of mechanically weak zones in the mid-lower crust, lateral and vertical variations in radial and azimuthal anisotropy, possible interplay of some fault zones with crustal weak zones, and importance of strike-slip faulting on upper crustal deformation. These results suggest that integration of block extrusion in the more rigid upper-middle crust and channel flow in the more ductile mid-lower crust will be more compatible with the current geophysical observations. Finally I discuss some future perspective researches in SE Tibet, including array-based tomography, joint inversion using multiple seismic data, and integration of geodynamic modeling and seismic observations. © 2012 The Seismological Society of China and Springer-Verlag Berlin Heidelberg.

Wen J.,Peking University | Chen X.,Hefei University of Technology
Bulletin of the Seismological Society of America | Year: 2012

The existence of f max has been perennially observed in various earthquakes. However, whether f max is caused by source processes (Papageorgiou and Aki, 1983) or site effects (Hanks, 1982) remains a controversial issue. With abundant near-fault strong ground-motion records, the Wenchuan earthquake provides an opportunity to validate the issue. By fitting the acceleration spectra of 10 seismic stations in the proximity of the fault on which the mainshock occurred, a set of f max values is obtained along the fault. The most notable feature of this set is its V-shaped distribution. The minimal f max value is recorded at the 051PXZ station near the epicenter, and f max increases as the distance deviates farther from the station. The maximal f max is recorded at the most northern station with respect to the epicenter. We estimate the cohesive zone size of the ruptured fault from the observed f max based on the source-cause model by Papageorgiou and Aki (1983). The sizes are remarkably consistent with the widths of the fault zone obtained from a totally independent study of the fault zone trapped waves (Li et al., 2009; Li et al., 2010). Therefore, the present study provides strong support to Papageorgiou and Aki's source-cause model for f max. Moreover, the V-shaped nonuni-form distribution of f max indicates a complicated rupture process of the Wenchuan earthquake, wherein the most energetic thrust faulting produces a thicker fault zone (approximately 400 m) around the epicenter, and an exhausted strike-slip faulting produces a thinner fault zone at the end portion of the fault (170-200 m).

Huang W.-D.,Virginia Polytechnic Institute and State University | Huang W.-D.,Hefei University of Technology | Percival Zhang Y.-H.,Virginia Polytechnic Institute and State University | Percival Zhang Y.-H.,U.S. Department of Energy
Energy and Environmental Science | Year: 2011

We compare the production of four biofuels - ethanol, butanol, fatty acid ethyl ester (palmitate ethyl ester, PEE), and hydrogen from renewable carbohydrate (glucose) based on the energy-retaining efficiency that is greatly influenced by thermodyanimcs, bioenergetics, and product separation. Ethanol and butanol are produced in anaerobic fermentations; PEE is produced in semi-aerobic fermentation; hydrogen is produced by cell-free synthetic enzymatic pathway biotransformation (SyPaB), where enzymes are produced from carbohydrate by microbial fermentations. A decreasing order in theoretical energy efficiency determined by thermodynamics is hydrogen, ethanol, butanol, and PEE. Bioenergetics analysis suggests that a small fraction of carbohydrate (e.g., 5-15%) is allocated to the synthesis of cell mass in anaerobic fermentations (e.g., ethanol and butanol), a significant fraction (e.g., 20-30% or higher) has to be allocated to the synthesis of cell mass for semi-aerobic fermentations (e.g., PEE production), and a very small fraction (e.g., less than 1%) is used to produce the enzyme mixtures. A decreasing order in product separation energy is hydrogen, secreted PEE, ethanol, butanol, and intracellular PEE. Hydrogen production by SyPaB would be most appealing because its energy-retaining efficiency is ∼49% higher than ethanol, ∼55% higher than butanol, and ∼87% higher than PEE, even without considering higher hydrogen-fuel cell efficiency than those of biofuel-internal combustion engines. Our analysis suggests that it may be difficult to produce some advanced biofuels economically through aerobic fermentations due to low energy efficiency, as compared to ethanol, butanol, and hydrogen. © 2011 The Royal Society of Chemistry.

Yang Y.T.,Hefei University of Technology
Acta Petrologica Sinica | Year: 2011

Lilhospheric flexure caused by orogenic loading is the main reason of the formation of foreland basins. The huge mass created, by crustal thickening associated with thrusting of a mountain belt causes the regional isostatic subsidence beneath the orogenic load, generating a depression adjacent and parallel to the mountain belt. In addition, the evolution of a foreland basin is also influenced by many other factors, such as sediment supply, the efficiency with which sediment is distributed in the basin, strength of the lithosphère, thrust rate of the mountain belt, eustatic sea-level change and dynamic subsidence related to subduction. This paper describes the relationships between these factors and subsidence of foreland basins, and introduces stratigraphie models related to episodic thrusting and the underfilled-overfilled stratigraphie model. It is hoped that this paper can become a useful reference for stratigraphie studies in foreland basins in Northwest China.

Zhou F.,Suzhou University of Science and Technology | Xin S.,Suzhou University of Science and Technology | Xin S.,Hefei University of Technology | Liang H.-W.,Suzhou University of Science and Technology | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2014

Traditional lithium-ion batteries that are based on layered Li intercalation electrode materials are limited by the intrinsically low theoretical capacities of both electrodes and cannot meet the increasing demand for energy. A facile route for the synthesis of a new type of composite nanofibers, namely carbon nanofibers decorated with molybdenum disulfide sheets (CNFs@MoS2), is now reported. A synergistic effect was observed for the two-component anode, triggering new electrochemical processes for lithium storage, with a persistent oxidation from Mo (or MoS2) to MoS3 in the repeated charge processes, leading to an ascending capacity upon cycling. The composite exhibits unprecedented electrochemical behavior with high specific capacity, good cycling stability, and superior high-rate capability, suggesting its potential application in high-energy lithium-ion batteries. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang G.,Hefei University of Technology | Wang G.,Key Laboratory of Process Optimization and Intelligent Decision making | Wang G.,City University of Hong Kong | Ma J.,City University of Hong Kong
Expert Systems with Applications | Year: 2012

Enterprise credit risk assessment has long been regarded as a critical topic and many statistical and intelligent methods have been explored for this issue. However there are no consistent conclusions on which methods are better. Recent researches suggest combining multiple classifiers, i.e.; ensemble learning, may have a better performance. In this paper, we propose a new hybrid ensemble approach, called RSB-SVM, which is based on two popular ensemble strategies, i.e.; bagging and random subspace and uses Support Vector Machine (SVM) as base learner. As there are two different factors, i.e.; bootstrap selection of instances and random selection of features, encouraging diversity in RSB-SVM, it would be advantageous to get better performance. The enterprise credit risk dataset, which includes 239 companies' financial records and is collected by the Industrial and Commercial Bank of China, is selected to demonstrate the effectiveness and feasibility of proposed method. Experimental results reveal that RSB-SVM can be used as an alternative method for enterprise credit risk assessment. © 2011 Elsevier Ltd. All rights reserved.

ANGUSTIFOLIA3 (AN3), a transcription coactivator, is implicated in modulating cell proliferation. In this study, I found that AN3 is a novel regulator of anthocyanin biosynthe