Entity

Time filter

Source Type

Xiamen, China

Xiamen University , colloquially known as Xia Da ". The university is one of many comprehensive universities directly administered by the Chinese Ministry of Education. In 1995 it was included in the list of the 211 Project for the state key construction; in 2000 it became one of China's higher-level universities designated for the state key construction of the 985 Project.According to University Undergraduates Teaching Assessment and Chinese Universities Evaluation Standings, the university is ranked 11th in China and has maintained the top 20 ranking in China, among which 6 subjects reach A++ level, including economics and management,fine art, law, chemistry, journalism, communication and mathematics.In addition,the school of management is accredited by EQUIS and AMBA. Wikipedia.


Xia Y.,Georgia Institute of Technology | Xia X.,Georgia Institute of Technology | Wang Y.,Southwest University | Xie S.,Xiamen University
MRS Bulletin | Year: 2013

The ability to control the shape of metal nanocrystals is central to advances in many areas of modern science and technology, including catalysis, plasmonics, electronics, and biomedicine. This article provides a brief overview of our recent efforts toward the development of solution-phase methods for shape-controlled synthesis of metal nanocrystals. While the synthetic methods only involve simple redox reactions, we have been working diligently to understand the complex nucleation and growth mechanisms leading to the formation of metal nanocrystals with desired shapes and related properties. We hope this review will inspire new ideas and concepts in the general area of nanomaterial synthesis, expand our ability to engineer the properties of metals for various applications, and contribute to the realization of sustainable use for some of the scarcest materials. © 2013 Materials Research Society. Source


Dang H.,Xiamen University | Dang H.,CAS Qingdao Institute of Bioenergy and Bioprocess Technology | Lovell C.R.,University of South Carolina
Microbiology and Molecular Biology Reviews | Year: 2016

Biotic and abiotic surfaces in marine waters are rapidly colonized by microorganisms. Surface colonization and subsequent biofilm formation and development provide numerous advantages to these organisms and support critical ecological and biogeochemical functions in the changing marine environment. Microbial surface association also contributes to deleterious effects such as biofouling, biocorrosion, and the persistence and transmission of harmful or pathogenic microorganisms and their genetic determinants. The processes and mechanisms of colonization as well as key players among the surface-associated microbiota have been studied for several decades. Accumulating evidence indicates that specific cell-surface, cell-cell, and interpopulation interactions shape the composition, structure, spatiotemporal dynamics, and functions of surface-associated microbial communities. Several key microbial processes and mechanisms, including (i) surface, population, and community sensing and signaling, (ii) intraspecies and interspecies communication and interaction, and (iii) the regulatory balance between cooperation and competition, have been identified as critical for the microbial surface association lifestyle. In this review, recent progress in the study of marine microbial surface colonization and biofilm development is synthesized and discussed. Major gaps in our knowledge remain. We pose questions for targeted investigation of surface-specific communitylevel microbial features, answers to which would advance our understanding of surface-associated microbial community ecology and the biogeochemical functions of these communities at levels from molecular mechanistic details through systems biological integration. Copyright © 2015, American Society for Microbiology. All Rights Reserved. Source


Ma R.,Xiamen University
Monthly Notices of the Royal Astronomical Society: Letters | Year: 2012

The correlation between radio and X-ray luminosity in the hard state of black hole X-ray binaries is important for unveiling the relation between the accretion flow and the jets. In this Letter, we have modelled the quasi-simultaneous multiband observations of a recently discovered transient X-ray source, IGR J17177-3656. It is found that the source is probably an outlier following the steep radio/X-ray correlation rather than an outlier in the transition region as suggested by Paizis et al. It is also found that the multiband spectrum can be successfully modelled by the luminous hot accretion flow (LHAF) but less likely by the advection dominated accretion flow. Our results support the point that LHAF can explain the steep radio/X-ray correlation. © 2012 The Author © Monthly Notices of the Royal Astronomical Society. © 2012 RAS. Source


Liu Y.,Xiamen University | Liu Q.H.,Duke University | Nie Z.,University of Electronic Science and Technology of China
IEEE Transactions on Antennas and Propagation | Year: 2014

Previously, the matrix pencil method (MPM) and the forward-backward MPM (FBMPM) were used to effectively reduce the number of antenna elements in the single-pattern linear arrays. This work extends the MPM and FBMPM-based synthesis methods to the synthesis of multiple-pattern linear arrays with a smaller number of elements. The extended MPM (resp., the extended FBMPM) method organizes all the multiple pattern data into a composite Hankel (resp., composite Hankel-Toeplitz) matrix from which the minimum number of elements and the common poles corresponding to element positions can be obtained with similar processing used in the original MPM or FBMPM synthesis method. In particular, the extended FBMPM inherits the advantage of the original FBMPM that a useful restriction is put on the distribution of poles, which makes the element positions obtained much more accurate and robust. Numerical experiments are conducted to validate the effectiveness and robustness of the proposed methods. For the tested cases, the element saving is about 20% ~ 25% for reconfigurable shaped patterns, and can be even more for electrically large linear arrays with scanned pencil-beams. © 1963-2012 IEEE. Source


Li X.,Xiamen University | Rakkiyappan R.,Gandhigram Rural University | Balasubramaniam P.,Gandhigram Rural University
Journal of the Franklin Institute | Year: 2011

This paper considers existence, uniqueness and the global asymptotic stability of fuzzy cellular neural networks with mixed delays. The mixed delays include constant delay in the leakage term (i.e., "leakage delay"), time-varying delays and continuously distributed delays. Based on the Lyapunov method and the linear matrix inequality (LMI) approach, some sufficient conditions ensuring global asymptotic stability of the equilibrium point are derived, which are dependent on both the discrete and distributed time delays. These conditions are expressed in terms of LMI and can be easily checked by MATLAB LMI toolbox. In addition, two numerical examples are given to illustrate the feasibility of the result. © 2010 The Franklin Institute. Source


Dai Y.,Nanyang Technological University | Wang Y.,Xiamen University | Liu B.,Nanyang Technological University | Yang Y.,Nanyang Technological University
Small | Year: 2015

(Figure Presented). Rapidly growing research interests surround heterogeneous nanocatalysis, in which metal nanoparticles (NPs) play a pivotal role as structure-sensitive active centers. With advances in nanotechnology, the morphology of metal NPs can be precisely controlled, which can provide well-defined models of nanocatalysts for understanding and optimizing the structure-reactivity correlations and the catalytic mechanisms. Benefiting from this, further credible evidence can be acquired on well-defined nanocatalysts rather than common multiphase systems, which is of great significance for the design and practical application of active metal nanocatalysts. Numerous studies demonstrate that enhanced structure-sensitive catalytic activity and selectivity are dependent not only on an increased surface-to-volume ratio and special surface atom arrangements, but also on tailored metal-metal and metal-organic-ligand interfaces, which is ascribed to the size, shape, composition, and ligand effects. Size-reactivity relationships and underlying size-dependent metal-oxide interactions are observed in many reactions. For bimetallic nanocatalysts, the composition and nanostructure play critical roles in regulating reactivities. Crystal facets favor individual catalytic selectivity and rates via distinct reaction pathways occurring on diverse atomic arrangements, both to low-index and high-index facets. High-index facets exhibit superior reactivities owing to their high-energy active sites, which facilitate rapid bond-breaking and new bond generation. Additionally, organic ligands may enhance the catalytic activity and selectivity of metal nanocatalysts via changing the adsorption energies of reactants and/or reaction energy barriers. Furthermore, atomically dispersed metals, especially single-atom metallic catalysts, have emerged recently, which can achieve better specific catalytic activity compared to conventional nanostructured metallic catalysts due to the low-coordination environment, stronger interaction with supports, and maximum service efficiency. Here, recent progress in shaped metallic nanocatalysts is examined and several parameters are discussed, as well as finally highlighting single-atom metallic catalysts and some perspectives on nanocatalysis. The integration of nanotechnology and nanocatalysis has been shaping up and, no doubt, the combination of sensitive characterization techniques and quantum calculations will play more important roles in such processes. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. Source


Wang W.,Northwest University, China | Zhao Y.,Xiamen University
Physical Chemistry Chemical Physics | Year: 2014

The dissociation and recombination rates of physisorbed H2, and the total dissociation rate of gas phase H2 on the rigid Ni(100) surface, as well as the corresponding kinetic isotope effects, are calculated by using the quantum instanton method, together with path integral Monte Carlo and adaptive umbrella sampling techniques. Both the dissociation and recombination rates of physisorbed H2 are dramatically enhanced by the quantum motions of H2 at low temperatures, for instance, the quantum rates are 43 and 7.5 times larger than the classical ones at 200 K, respectively. For the dissociation of gas phase H2, at high temperatures, the H 2 can fly over the physisorbed state and dissociate directly, however, at low temperatures, the H2 is first physisorbed and then dissociates under steady state approximation. The total dissociation rate of gas phase H2 can be expressed as a combination of the direct and steady state dissociation rates. It has the form of an inverted bell with a minimum value at about 400 K, and detailed analysis shows that the dissociation of gas phase H2 is dominated by a steady state process below 400 K, however, both the steady state and direct processes are important above 400 K. The calculated kinetic isotope effects reveal that H2 always has larger rates than D2 no matter which dissociative process they undergo. © 2014 The Owner Societies. Source


Yu J.,Xiamen University | Tao D.,Intelligent Systems Technology, Inc. | Rui Y.,Microsoft | Cheng J.,CAS Shenzhen Institutes of Advanced Technology | Cheng J.,Chinese University of Hong Kong
Pattern Recognition | Year: 2013

Recently, we have witnessed a surge of interests of learning a low-dimensional subspace for scene classification. The existing methods do not perform well since they do not consider scenes' multiple features from different views in low-dimensional subspace construction. In this paper, we describe scene images by finding a group of features and explore their complementary characteristics. We consider the problem of multiview dimensionality reduction by learning a unified low-dimensional subspace to effectively fuse these features. The new proposed method takes both intraclass and interclass geometries into consideration, as a result the discriminability is effectively preserved because it takes into account neighboring samples which have different labels. Due to the semantic gap, the fusion of multiview features still cannot achieve excellent performance of scene classification in real applications. Therefore, a user labeling procedure is introduced in our approach. Initially, a query image is provided by the user, and a group of images are retrieved by a search engine. After that, users label some images in the retrieved set as relevant or irrelevant with the query. The must-links are constructed between the relevant images, and the cannot-links are built between the irrelevant images. Finally, an alternating optimization procedure is adopted to integrate the complementary nature of different views with the user labeling information, and develop a novel multiview dimensionality reduction method for scene classification. Experiments are conducted on the real-world datasets of natural scenes and indoor scenes, and the results demonstrate that the proposed method has the best performance in scene classification. In addition, the proposed method can be applied to other classification problems. The experimental results of shape classification on Caltech 256 suggest the effectiveness of our method. © 2012 Elsevier Ltd. Source


Gu W.-M.,Xiamen University
Astrophysical Journal | Year: 2015

Based on the no-outflow assumption, we investigate steady-state, axisymmetric, optically thin accretion flows in spherical coordinates. By comparing the vertically integrated advective cooling rate with the viscous heating rate, we find that the former is generally less than 30% of the latter, which indicates that the advective cooling itself cannot balance the viscous heating. As a consequence, for radiatively inefficient flows with low accretion rates such as M ≲ 10-3 MEdd, where MEdd is the Eddington accretion rate, the viscous heating rate will be larger than the sum of the advective cooling rate and the radiative cooling one. Thus, no thermal equilibrium can be established under the no-outflow assumption. We therefore argue that in such cases outflows ought to occur and take away more than 70% of the thermal energy generated by viscous dissipation. Similarly, for optically thick flows with extremely large accretion rates such as M ≳ 10 MEdd, outflows should also occur owing to the limited advection and the low efficiency of radiative cooling. Our results may help to understand the mechanism of outflows found in observations and numerical simulations. © 2015. The American Astronomical Society. All rights reserved. Source


Dong Y.,Xiamen University | Williams G.A.,University of Hong Kong
Marine Biology | Year: 2011

Understanding variation in physiological adaptations to thermal stress is vital when investigating intertidal species' distribution patterns. The thermal sensitivities of two limpets, Cellana grata and C. toreuma, differed in accordance with their vertical distributions. Cardiac performance was maintained at higher temperatures (~47°C) for the high-zone C. grata than the mid-zone C. toreuma (~42°C). At 40°C, C. grata maintained regular heart function for ~4 h, while heart function of C. toreuma decreased rapidly. Heat shock protein expression revealed that C. toreuma had two constitutive isoforms, Hsp77 and Hsp72, and C. grata one inducible form, Hsp75, which was upregulated at 40°C, suggesting C. grata has a more effective heat shock response than C. toreuma. The temperature-adaptive differences in cardiac thermal tolerance and Hsp expression match observed differences in thermally induced mortalities with the onset of summer and may help predict differential effects of climate change on the two congeners. © 2011 Springer-Verlag. Source


Li X.,Xiamen University | Shen J.,Hangzhou Normal University
IEEE Transactions on Neural Networks | Year: 2010

In this paper, a class of impulsive interval neural networks with discrete and distributed time-varying delays is discussed. Several new sufficient conditions are obtained ensuring the existence, uniqueness, and global exponential stability of periodic solution (i.e., stationary oscillation) for the addressed models based on inequality analysis techniques. The obtained results can be checked easily by the linear matrix inequality control toolbox in MATLAB. Finally, two numerical examples are given to show the effectiveness of our results. © 2010 IEEE. Source


Teo B.K.,Xiamen University | Teo B.K.,Peking University
Journal of Cluster Science | Year: 2014

In this article, the interdisciplinary science of clusters is discussed in general terms. Different types of clusters across vast scales of matter, energy, space, and time in the physical world are discussed. Specific examples of clusters in chemistry and physics are used to illustrate various principles or models of clustering processes of atoms and molecules as well as to demonstrate the exquisite beauty and pattern of clusters and the clustering phenomena so ubiquitous in nature. Nowadays, "designer clusters" can be made with tailorable properties and used as "building blocks" to form supermolecules, or to construct large cluster-based hierarchical materials with tunable properties, or to fabricate cluster-based devices with specific functions, etc., thereby providing a materials base for nanotechnology. Clustering is a spontaneous self-assembly process and the similarity across scales reflects the intrinsic self-organization and self-similarity principle of the physical world. Geometry and symmetry transcend all clustering processes, in ordered as well as in disordered systems. © 2013 Springer Science+Business Media New York. Source


Wang H.,University of Science and Technology Beijing | Wang K.,University of Science and Technology Beijing | Tao J.,Xiamen University | Jiang J.,University of Science and Technology Beijing
Chemical Communications | Year: 2012

Correlation between molecular structures and slow relaxation of magnetization of three mixed (phthalocyaninato)(porphyrinato) dysprosium(iii) double-deckers clearly reveals the effect of the sandwich-type molecular structure, in particular the twist angle, on the quantum tunneling (QT) at zero dc field of these complexes, providing the first direct evidence to the theoretical inference. © 2012 The Royal Society of Chemistry. Source


Li B.,Xiamen University
International Journal of Digital Content Technology and its Applications | Year: 2010

To solve the cruise two-dimensional revenue management problem and develop such an auto mated system under uncertain environment, a static model which is a stochastic integer programming I sfirstly constructed to maximize the total expected revenue from all kinds of cruise products. Four methods can be applied to solve the above model, which are chance constrained programming, robust optimization, deterministic programming, and bid-price control. In the chance constrained programming method, the stochastic constraints are converted into deterministic equivalent forms. In the robust optimization method, the model is transformed into a goal programming formulations with ascenario-based description of problem data. In the deterministic programming method, the stochastic demand variable is directly replaced with the mean value or expected value of demand. In the bid-price control, the rules for accepting cruise products are proposed. Further, to consider time-variable dem and and increase the profit, a dynamic capacity allocation model for cruise two-dimensiona lrevenue management is put forward by applying Markov Decision Process. Then the accept/reject optimal policies for a booking request of cruise products are obtained. The conclusions are as follows:(1) the capacity in the cruise line industry is two-dimensional, that is, the number of cabins and life bo at seats can both affect availability of cruise products; (2) the demand for all kinds of cruise products is uncertain and the uncertainty can be coped with four solution methods; (3) the characteristics of the cruise industry and time-variable demand have to be incorporated into the static and dynamic capacity allocation models to maximize the expected revenue of the cruise line. Source


Lin B.,Minjiang University | Liu X.,Xiamen University
Energy | Year: 2012

Promoting technological development to improve energy efficiency has been the primary method of energy conservation in China. However, the existence of energy rebound effect will impose negative effects on the final result of energy saving. In this article, we adopt the Malmquist index approach to estimate the contribution of technological progress to economic growth. We also employ Logarithmic mean weight Divisia index (LMDI) to measure the impact of technological improvement on the energy intensity. Based on the above, we set up a model to estimate the technology-based energy rebound effect in China. The results show that, over 1981-2009, energy rebound effect amounts averagely to 53.2%, implying that China cannot simply rely on technical means to reduce energy consumption and emission. Economic instruments should also be applied as supplements to ensure results of energy conservation and emission reduction. © 2012. Source


Li Y.,Xiamen University | Dabo I.,University Paris Est Creteil
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Plane-wave electronic-structure predictions based upon orbital-dependent density-functional theory (OD-DFT) approximations, such as hybrid density-functional methods and self-interaction density-functional corrections, are severely affected by computational inaccuracies in evaluating electron interactions in the plane-wave representation. These errors arise from divergence singularities in the plane-wave summation of electrostatic and exchange interaction contributions. Auxiliary-function corrections are reciprocal-space countercharge corrections that cancel plane-wave singularities through the addition of an auxiliary function to the point-charge electrostatic kernel that enters into the expression of interaction terms. At variance with real-space countercharge corrections that are employed in the context of density-functional theory (DFT), reciprocal-space corrections are computationally inexpensive, making them suited to more demanding OD-DFT calculations. Nevertheless, there exists much freedom in the choice of auxiliary functions and various definitions result in different levels of performance in eliminating plane-wave inaccuracies. In this work we derive exact point-charge auxiliary functions for the description of molecular structures of arbitrary translational symmetry, including the yet unaddressed one-dimensional case. In addition, we provide a critical assessment of different reciprocal-space countercharge corrections and demonstrate the improved accuracy of point-charge auxiliary functions in predicting the electronic levels and electrical response of conjugated polymers from plane-wave OD-DFT calculations. © 2011 American Physical Society. Source


Min W.,Xiamen University
Journal of Convergence Information Technology | Year: 2010

The theory of customer relationship management has been gradually penetrated into all levels of enterprise management. As a close business with customers, travel agency should focus on customer relationship management, which is very important. This paper attempts to combine the concept of customer relationship management and the processes of traditional travel agency marketing to construct the system architecture, considering the actual situation and specific requirements of a travel agency, combining with norms and standards of the management of travel agencies industry, as well as, using the current popular system architecture B/S (Browser/Sever) Mode. By extensively studying the theory of software engineering, database theory and object-oriented languages and Web programming, management information systems analysis and design process of travel agency marketing is discussed in detail based CRM. Source


Jiang Z.,Shanghai University of Finance and Economics | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy Policy | Year: 2012

China is currently in the process of industrialization and urbanization, which is the key stage of transition from a low-income country to a middle-income country and requires large amount of energy. The process will not end until 2020, so China's primary energy demand will keep high growth in the mid-term. Although each country is unique considering its particular history and background, all countries are sharing some common rules in energy demand for economic development. Based on the comparison with developed countries, here, we report some rules in the process of industrialization and urbanization as follows: (1) urbanization always goes along with industrialization; (2) the higher economic growth is, the higher energy demand is; (3) economic globalization makes it possible to shorten the time of industrialization, but the shorter the transition phase is, the faster energy demand grows; (4) the change of energy intensity presents as an "inverted U" curve, but whose shape can be changed for different energy policy. The above rules are very important for the Chinese government in framing its energy policy. © 2012 Elsevier Ltd. Source


John J.,CEA Saclay Nuclear Research Center | Gravel E.,CEA Saclay Nuclear Research Center | Hagege A.,CEA Marcoule Nuclear Site | Hagege A.,French Atomic Energy Commission | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2011

Turning over silanes: The first nanotube-based catalytic system for silane oxidation is reported (see scheme). The reusable gold-nanotube hybrid cleanly oxidizes both alkyl and aryl silanes in high yields, under mild reaction conditions, and compares most favorably to any other catalytic system in terms of overall efficacy and turnover values. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Lin B.,Minjiang University | Lin B.,Xiamen University | Jiang Z.,Shanghai University of Finance and Economics
Energy Policy | Year: 2012

Electricity is the guarantee of normal life, and the electricity price is widely concerned. As a developing country in the transition stage, abundant policy implications are included in the electricity price in China, thus, whether to adjust the resident electricity price is a dilemma for the government. However, the current single tariff system cannot cope with the complex social and environmental problems. A new price mechanism is indeed needed. This paper tries to design an increasing block tariffs system with the consideration of residential income and electricity consumption. The result indicates that the increasing block tariffs system with four-tier structure is more reasonable for China. Although the increasing block tariffs will result in the increase of electricity price, it is still acceptable and affordable. The increasing block tariffs will greatly improve the equity and efficiency, and promote the electricity saving and emissions reduction. Moreover, the power companies will increase tariffs revenue, which would use to the transmission networks investment in poor area. In order to the offset the limitations of the increasing block tariffs, the government should adopt some complementary measures. © 2011 Elsevier Ltd. Source


Merlitz H.,Xiamen University
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

Sixty years ago, August Sonnefeld of Zeiss reported on observations with experimental telescopes. The goal of his investigation was to determine the ideal amount of distortion applied to optical instruments that are used in combination with the human eye. His studies were inconclusive and partially contradictory. We have picked up this problem once again, adopting a modern point of view about the human imaging process, and supported by computer graphics. Based on experiments with Helmholtz checkerboards, we argue that human imaging introduces a certain amount of barrel distortion, which has to be counterbalanced through the implementation of an equally strong pincushion distortion into the binocular design. We discuss in detail how this approach is capable of eliminating the globe effect of the panning binocular and how the residual pincushion distortion affects the image when the eye is pointing off-center. Our results support the binocular designer in optimizing his instrument for its intended mode of application, and may help binocular users and astronomers better understand their tools. © 2009 Optical Society of America. Source


Zhang W.,Nanjing Normal University | Hou Z.F.,Xiamen University
Physica Status Solidi (B) Basic Research | Year: 2013

We have studied the interaction between two neutral oxygen vacancies and the electronic structures of oxygen divacancy in the monoclinic phase of HfO2 by performing the first-principles calculations. It is found that the vacancy-vacancy interaction depends not only on the distance but also on the coordination of the removed oxygen atoms. The oxygen divacancy is formed energetically by the removal of two fourfold coordinated oxygen atoms (O4) with a distance of about 2.73Å. The interaction between two O4 vacancies is attractive, indicating that the O4 vacancies tend to form stable cluster in HfO2. The oxygen divacancy induces two in-gap defect levels, which correspond to a bonding state and an anti-bonding one. These results would provide insightful information to understand the formation of conductive filaments in HfO2-based resistive random access memory devices. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Yang L.,Xiamen University
International Review on Computers and Software | Year: 2012

Based on the study of existing reader anti-collision algorithm, this paper first generally describes the reader algorithm, analyzes the classification and mechanism of the RFID (Radio Frequency Identification) reader anti-collision (collision avoidance), discussion and analysis of the Pluse algorithm theory, and puts forward an improved reader anti-collision algorithm and its processes. The simulation analysis shows that the improved algorithm is simple, well able to avoid the network conflict of RFID reader. In the simulation the improved PLUSE algorithm is compared with two other reader anti-collision algorithms. The result indicates that the proposed algorithm has advances in system input output and efficiency, which verifies the rationality and effectiveness of the algorithm, providing a way method for the study of reader anti-collision algorithm based on RFID, which has certain referencing and extending value in application. © 2012 Praise Worthy Prize S.r.l. - All right reserved. Source


Lvqing Y.,Xiamen University
Journal of Convergence Information Technology | Year: 2012

According to the software engineering life cycle and software development process theory, the thesis analyzes and designs the campus general processes and functions on the basis of the Internet of things, based on the research on the process of campus generation work. The paper describes the goal of building the system, analyzes the system's functional requirements that assist school attendance and protect the safety of students on campus by the nuclear technology of RFID to collect, locate, track, send, query and statistics the information about students' entering or outing the campus and their position. Meanwhile, the paper analyzes the system's security, reliability and usability and other nonfunctional requirements. On this basis, the paper designs the physical structure of the platform, four layers of software architecture, development environment and important system interfaces and indicates key technologies to new ways, such as electronic labels and face identity, improving information quantity and accuracy, RFID and GIS spatial orientation. Finally, the implemented function and performance in the system indicated that the platform has been designed with good reasonability and efficiency. Source


Wang X.-D.,University of Regensburg | Wang X.-D.,Xiamen University | Meier R.J.,University of Regensburg | Link M.,University of Regensburg | Wolfbeis O.S.,University of Regensburg
Angewandte Chemie - International Edition | Year: 2010

(Figure Presented) O2, where are you? The spatial distribution of oxygen can be imaged with a conventional digital camera by making use of a specially designed fluorescent sensor film containing a quenchable redemitting probe for oxygen along with a green-emitting reference fluorophore. The technique exploits the RGB channels involved in digital photography (see picture) to deliver a simple method for quantitative sensing and imaging of this important species. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA, weinheim. Source


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. Source


Li X.,Xiamen University | Li X.,University of Illinois at Urbana - Champaign | Zheng W.,University of Illinois at Urbana - Champaign | Kelly W.R.,University of Illinois at Urbana - Champaign
Science of the Total Environment | Year: 2013

Rural communities in the United States usually use a series of aerated lagoons to treat domestic wastewater. Effluents from these systems are typically discharged to receiving watersheds, which leads to a potential transfer of pharmaceuticals and personal care products (PPCPs) and steroid hormones from sanitary sewage to the environment. The primary objectives of this study are to identify and quantify PPCPs and steroid hormones in rural sewage treatment lagoons, to investigate the removal efficiency of these emerging contaminants in the treatment processes, and to monitor their occurrence in the surrounding watershed. In this study, a method has been developed to analyze thirteen PPCPs and eight steroid hormones in various water samples. Among all of the PPCPs considered, ten chemicals were detected in sewage influents, lagoon waters of different treatment stages, or effluents at concentrations in the ng/L to low μg/L range. Three hormones were observed in the influents at total concentrations as high as 164. ng/L, but no hormone residues were detected in the effluents. This indicates that the aerated lagoons may effectively remove hormone contaminants. With the exception of carbamazepine, removal rates for the other detected PPCPs were relatively high in the range of 88 to 100% in September with average air temperature equal to 20°C. However, the removal efficiency of nine PPCPs in the rural wastewater treatment plant exhibited large temporal variability. The concentrations of PPCPs in the lagoon waters and effluents collected in November, with average air temperature equal to 4.4°C, were 1-2 orders of magnitude higher than those samples collected in September. Occurrence of these PPCP contaminants in the surrounding watershed was also monitored. The discharge of effluents significantly elevated the PPCP concentrations in the receiving creek and increased their occurrence in the adjacent river. © 2012 Elsevier B.V. Source


Zhou Z.-D.,Xiamen University | Yang F.-P.,Shanghai JiaoTong University
Acta Mechanica | Year: 2014

The present paper analyzes the propagation of plane waves in an infinite pyroelectric medium. In order to consider the real situation, a new thermo-electric-elastic model with viscous effect is presented. The theoretical analysis shows that the elastic viscous effect and the Fourier's law are in the same level in the evolution equations. So, the thermal viscous effect in Cattaneo's equation belongs to a second-order effect. Numerical calculations are performed for pyroelectric material BaTiO3 using three models (Kaliski-Lord-Shulman theory, inertial entropy theory and inertial entropy with viscous effect). Results show that the elastic viscous relaxation time τ 0 plays a large role on the mechanical waves and admits mechanical waves decaying in propagation process. The effects of the thermo-relaxation time τ s on the attenuation of mechanical waves are also researched and discussed in detail. © 2013 Springer-Verlag Wien. Source


Xiao L.,Xiamen University | Dai H.,North Carolina State University | Ning P.,North Carolina State University
IEEE Transactions on Information Forensics and Security | Year: 2012

We propose a jamming-resistant collaborative broadcast scheme for wireless networks, which utilizes the Uncoordinated Frequency Hopping (UFH) technique to counteract jamming without preshared keys, and exploits node cooperation to achieve higher communication efficiency and stronger jamming resistance. In this scheme, nodes that already obtain the broadcast message serve as relays to help forward it to other nodes. Relying on the sheer number of relay nodes, our scheme provides a new angle for jamming countermeasure, which not only significantly enhances the performance of jamming-resistant broadcast, but can readily be combined with other existing or emerging antijamming approaches in various applications. We present the collaborative broadcast protocol, and analyze its successful packet reception rate and the corresponding cooperation gain for both synchronous and asynchronous relays for a snapshot scenario. We also investigate the full broadcast process based on a Markov chain model and derive a closed-form expression of the average broadcast delay. Simulation results in both single-hop and multihop networks indicate that our scheme is a promising antijamming technique in wireless networks. © 2011 IEEE. Source


Leung S.C.H.,City University of Hong Kong | Zhang D.,Xiamen University
Expert Systems with Applications | Year: 2011

In this paper, an orthogonal strip packing problem with rotation of items and without the guillotine packing constraint is considered. A fast heuristic algorithm for the large-scale problems is presented. This heuristic algorithm is mainly based on heuristic strategies inspired by the wall-building rule of bricklayers in daily life. The heuristics is simple and the setting of parameter is not required. Each layer is initialized with either a single item or a bunch of equal-width items. The remaining part of the layer is filled by a bottom-left strategy preferring items which eliminate corners of the current layout. Items can also be placed across several layers. Then, the evaluation rule, which is based on the fitness value for different rectangles to a given position, is able to select an appropriate rectangle to pack. The computational results on a broad range of benchmark problems show that the fast layer-based heuristic algorithm can compete with other latest heuristics and meta-heuristics from the literature in terms of both solution quality and computational time. The fast layer-based heuristic algorithm can compete with the latest published algorithms. In particular, it performs better for large-scale problem instances. © 2010 Elsevier Ltd. All rights reserved. Source


In order to examine whether catalyst granular size was a factor for tar removal and syngas composition enhancement, three Ni/char catalysts with 90-100 mesh (Ni/SC), 50-60 mesh (Ni/MC), and 20-30 mesh (Ni/LC) size were prepared with a mechanical mixing method and tested in an updraft gasifier. Reforming parameters investigated were the reaction temperature (650-850°C), the Ni loading (5-20% of the weight of char support), and the gas residence time (0.1-1.2 s). It was found that the catalyst granular size affected the diffusion of reactants, as well as of products. Ni/SC, Ni/MC, and Ni/LC removed more than 96.5% of the tars in syngas at 800 °C reforming temperature, 15 wt. % Ni loading, and 0.3 s gas residence time. Tar removal efficiencies increased with the decrease of Ni/char granular size, which can be attributed to the higher active surface area with the Ni/SC catalyst. As the catalyst granular size was increased, the H2 content in the syngas was increased and the CO content was significantly decreased. The total amount of combustible gases (H2, CO, and CH4) obtained in the syngas with Ni/MC was higher than with Ni/SC or Ni/LC. It was concluded that Ni/char, especially Ni/MC, can be considered as an effective and inexpensive catalyst for biomass gasification tar removal and syngas conditioning. Source


China’s rapid development places growing pressure on its water resources, including its considerable transboundary waters. This paper analyses the current situation of China’s transboundary water regimes through a legal analytical framework. The evaluation of treaty and state practice reveals that while China adheres to and follows some fundamental rules of international water law, gaps remain. New trends in China’s state practice and in the field of international law offer interesting opportunities for addressing these shortcomings. © 2014 International Water Resources Association. Source


Ge X.,Huazhong University of Science and Technology | Huang K.,Huazhong University of Science and Technology | Wang C.-X.,Heriot - Watt University | Hong X.,Xiamen University | Yang X.,Huazhong University of Science and Technology
IEEE Transactions on Wireless Communications | Year: 2011

Characterization and modeling of co-channel interference is critical for the design and performance evaluation of realistic multi-cell cellular networks. In this paper, based on alpha stable processes, an analytical co-channel interference model is proposed for multi-cell multiple-input multi-output (MIMO) cellular networks. The impact of different channel parameters on the new interference model is analyzed numerically. Furthermore, the exact normalized downlink average capacity is derived for a multi-cell MIMO cellular network with co-channel interference. Moreover, the closed-form normalized downlink average capacity is derived for cell-edge users in multi-cell multiple-input single-output (MISO) cooperative cellular networks with co-channel interference. From the new co-channel interference model and capacity formulas, the impact of cooperative antennas and base stations on cell-edge user performance in the multi-cell multi-antenna cellular network is investigated by numerical methods. Numerical results show that cooperative transmission can improve the capacity performance of multi-cell multi-antenna cooperative cellular networks, especially in a scenario with a high density of interfering base stations. The capacity performance gain is degraded with the increased number of cooperative antennas or base stations. © 2011 IEEE. Source


Sun I.,University of Delaware | Hu R.,Xiamen University | Wu Y.,Wayne State University
Australian and New Zealand Journal of Criminology | Year: 2012

Trust in the police has emerged as a critical issue in China where the police have experienced a crisis of legitimacy. Only a small number of studies, however, have empirically assessed Chinese citizens' trust in the police. Moreover, the effects of citizens' participation in social and political activity on evaluations of the police have rarely been investigated. Using survey data collected from over 3,500 Chinese citizens in eight cities, this study examines the impact of social capital and political participation on trust in the police, controlling for demographic characteristics, sense of safety, and locality. Trust in the leaders of neighborhood committees increased the likelihood of trust in the police. A sense of safety also raised the odds of trust in the police. Citizens' trust in the police is also predicted by trust in neighbors, participation in political activity, and gender. Trust in the police varies across cities and is explained by some common and distinctive variables. © The Author(s) 2012 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav. Source


Xin X.,Georgia Institute of Technology | Liu H.-Y.,University of Delaware | Ye M.,Xiamen University | Lin Z.,Georgia Institute of Technology
Nanoscale | Year: 2013

By combining the ease of producing ZnO nanoflowers with the advantageous chemical stability of TiO2, hierarchically structured hollow TiO 2 flower-like clusters were yielded via chemical bath deposition (CBD) of ZnO nanoflowers, followed by their conversion into TiO2 flower-like clusters in the presence of TiO2 precursors. The effects of ZnO precursor concentration, precursor amount, and reaction time on the formation of ZnO nanoflowers were systematically explored. Dye-sensitized solar cells fabricated by utilizing these hierarchically structured ZnO and TiO 2 flower clusters exhibited a power conversion efficiency of 1.16% and 2.73%, respectively, under 100 mW cm-2 illumination. The intensity modulated photocurrent/photovoltage spectroscopy (IMPS/IMVS) studies suggested that flower-like structures had a fast electron transit time and their charge collection efficiency was nearly 100%. © 2013 The Royal Society of Chemistry. Source


The infrared spectra of (1′S, 6′S)-1-cyclopropyl-7-(2,8- diazabicyclo[4.3.0] non-8-yl)-6-fluoro-8-methoxy-4-oxo-1,4-dihydroquinoline-3- carboxylic acid hydrochloride salt (CLF-HCl) were studied and compared with free base. Their fragmentation pathways were investigated using tandem mass spectrometric (MS/MS) techniques on Fourier-transform ion cyclotron resonance spectrum, and many characteristic fragment ions were found. © 2013 Elsevier B.V. All rights reserved. Source


Wang Y.-M.,Fuzhou University | Chin K.-S.,City University of Hong Kong | Luo Y.,Xiamen University
Expert Systems with Applications | Year: 2011

Cross-efficiency evaluation is an effective approach to ranking decision making units (DMUs) that utilize multiple inputs to produce multiple outputs. Its models can usually be developed in a way that is either aggressive or benevolent to other DMUs, depending upon the decision maker (DM)'s subjective preference to the two extreme cases. This paper proposes several new data envelopment analysis (DEA) models for cross-efficiency evaluation by introducing a virtual ideal DMU (IDMU) and a virtual anti-ideal DMU (ADMU). The new DEA models determine input and output weights from the point of view of distance from IDMU or ADMU without the need to be aggressive or benevolent to any DMUs. As a result, the cross-efficiencies measured by these new DEA models are neutral and more logical. Numerical examples are provided to illustrate the potential applications of these new DEA models and their effectiveness in ranking DMUs. © 2011 Published by Elsevier Ltd. Source


Fu N.,Monash University | Chen X.D.,Monash University | Chen X.D.,Xiamen University
Food Research International | Year: 2011

Freeze-drying is a traditional approach of producing desiccated microorganisms. Industrial mass-production of desiccated microorganisms, however, pursues a more economic drying process, which leads to an increasing research interest in the thermal drying processes of microorganisms. These thermal drying processes include spray drying, fluidized bed drying, vacuum drying, air-convective drying, etc. Cells being thermally dried suffer from simultaneous heat and dehydration stresses. To maximize the cell survival and to study the mechanisms of cell inactivation during such processes, it is necessary to have understandings of both the chemical engineering principles involved and the biological properties of the microorganisms to be dried. This review attempts to give a balanced discussion on both aspects. Factors influencing cell viability during thermal drying are discussed in two groups, viz., intrinsic factors related to the microorganisms being dried and extrinsic factors related to process conditions. Finally, modeling of the inactivation kinetics is briefly reviewed. This article aims to bring together some common observations and findings for different organisms subjected to thermal drying, and discuss the mechanism underlying these observations. Efficient drying which is associated with fast removal of water content has economical benefits, but hurts cells. The desiccation of microorganism thus is a balance between these two considerations and needs to be strain-specifically optimized. © 2011 Elsevier Ltd. Source


Du K.,Xiamen University | Du K.,City University of Hong Kong
Journal of Computational Physics | Year: 2011

We consider electromagnetic scattering from two-dimensional (2D) overfilled cavities embedded in an infinite ground plane. The unbounded computational domain is truncated to a bounded one by using a transparent boundary condition (TBC) proposed on a semi-ellipse. For overfilled rectangular cavities with homogeneous media, another TBC is introduced on the cavity apertures, which produces a smaller computational domain. The existence and uniqueness of the solutions of the variational formulations for the transverse magnetic and transverse electric polarizations are established. In the exterior domain, the 2D scattering problem is solved in the elliptic coordinate system using the Mathieu functions. In the interior domain, the problem is solved by a finite element method. Numerical experiments show the efficiency and accuracy of the new boundary conditions. © 2011 Elsevier Inc. Source


Ji X.,University of California at Berkeley | Lu H.,Xiamen University | Zhou Q.,University of California at Berkeley | Luo K.,Lawrence Berkeley National Laboratory
eLife | Year: 2014

Transcriptional elongation by RNA polymerase (Pol) II is essential for gene expression during cell growth and differentiation. The positive transcription elongation factor b (P-TEFb) stimulates transcriptional elongation by phosphorylating Pol II and antagonizing negative elongation factors. A reservoir of P-TEFb is sequestered in the inactive 7SK snRNP where 7SK snRNA and the La-related protein LARP7 are required for the integrity of this complex. Here, we show that P-TEFb activity is important for the epithelial-mesenchymal transition (EMT) and breast cancer progression. Decreased levels of LARP7 and 7SK snRNA redistribute P-TEFb to the transcriptionally active super elongation complex, resulting in P-TEFb activation and increased transcription of EMT transcription factors, including Slug, FOXC2, ZEB2, and Twist1, to promote breast cancer EMT, invasion, and metastasis. Our data provide the first demonstration that the transcription elongation machinery plays a key role in promoting breast cancer progression by directly controlling the expression of upstream EMT regulators. Copyright © 2014, Ji et al. Source


Duan H.,Xiamen University | Hu Q.,GIZ GmbH
Journal of Cleaner Production | Year: 2014

To successfully implement climate policy at different levels, local officials should have a better understanding of climate change issues. Using 191 valid questionnaires collected in 13 district cities in Jiangsu, China, this study found that local officials are aware of climate change and that they demonstrate a strong willingness to improve their understanding of climate science, management approaches, and climate policy. Further analysis reveals that officials working outside of the climate-related field showed stronger demands for enhancing their knowledge about climate change than those working in the field. The research suggests that the Jiangsu government would need to integrate capacity building into climate policy and take a systematic approach to equip local officials with newest scientific knowledge, policy developments, and necessary capacities for addressing climate change and pushing forward local low carbon development. © 2013 Elsevier Ltd. All rights reserved. Source


Du K.,Xiamen University | Lu H.,University of Connecticut | Yu K.,Fudan University
Applied Energy | Year: 2014

Taking the underlying technology heterogeneity into account, this paper uses a nonparametric metafrontier approach to estimate the CO2 emission efficiency and the potential emission reduction of China's 30 provinces for the period 2006-2010. The sources of the potential emission reduction are identified as managerial failure and technology gap. The proposed models are estimated using linear programming method. The main findings are as follows. Firstly, the potential CO2 emission reduction is averagely 56.2million tons for each province, and 1687million tons for the whole country. Secondly, over half of the potential emission reduction is caused by technology gap. Thirdly, the major contributor to the potential emission reduction varies across different regions, as management inefficiency for the east area and technology gap for the central and west areas. © 2013 Elsevier Ltd. Source


Chen L.,Xiamen University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

I propose a practical scheme of hyperconcentration, by which two-qubit photon spin and two-qudit orbital angular momentum (OAM) maximally entangled states can be distilled simultaneously. The original nonmaximally hyperentangled photon pairs are generated by parametric down conversion and the symmetrical procrustean concentration is then performed using pairs of spatial light modulators (operating on OAM) and partial polarizing interferometers (operating on spin). Furthermore, I show that a generalized Shannon dimensionality can be introduced to evaluate the performance, which is maximized with the formation of a comblike entangled spectrum for composite spin-orbit modes. The results hold promise for ultrahigh-dimensional quantum-information processing. © 2012 American Physical Society. Source


Tang S.,Gannan Normal University | Cao Z.,Xiamen University
Physical Chemistry Chemical Physics | Year: 2012

Graphene oxides (GOs) may offer extraordinary potential in the design of novel catalytic systems due to the presence of various oxygen functional groups and their unique electronic and structural properties. Using first-principles calculations, we explore the plausible mechanisms for the oxidative dehydrogenation (ODH) of propane to propene by GOs and the diffusion of the surface oxygen-containing groups under an external electric field. The present results show that GOs with modified oxygen-containing groups may afford high catalytic activity for the ODH of propane to propene. The presence of hydroxyl groups around the active sites provided by epoxides can remarkably enhance the C-H bond activation of propane and the activity enhancement exhibits strong site dependence. The sites of oxygen functional groups on the GO surface can be easily tuned by the diffusion of these groups under an external electric field, which increases the reactivity of GOs towards ODH of propane. The chemically modified GOs are thus quite promising in the design of metal-free catalysis. © 2012 the Owner Societies. Source


Du K.,Xiamen University
Journal of Computational Physics | Year: 2011

In this paper, we propose a composite preconditioner for the electromagnetic scattering from a large cavity. The electromagnetic cavity problem is described by the Helmholtz equation with a nonlocal boundary condition on the aperture of the cavity and Dirichlet (or Neumann) boundary conditions on the walls of the cavity. The preconditioner proposed here combines the optimal sine transform based approximation with a layered medium model. Using fast Fourier transforms, the computational cost of every iteration is O(N2logN) on an N× N uniform partition of the unit square. Numerical results for a model problem show that the new preconditioner is more efficient than those recently considered in the literature. For the cavity with a small portion of non-layered media, we propose a sparse preconditioned conjugate orthogonal conjugate gradient solver combined with the new preconditioner. Numerical results for a model problem are reported to demonstrate the efficiency of the sparse solver. © 2011 Elsevier Inc. Source


Huang S.,Xiamen University | Li Y.,Xiamen University of Technology | Shang S.,Xiamen University of Technology
Optics Express | Year: 2013

Spectral optimization algorithm (SOA) is a well-accepted scheme for the retrieval of water constituents from the measurement of ocean color radiometry. It defines an error function between the input and output remote sensing reflectance spectrum, with the latter modeled with a few variables that represent the optically active properties, while the variables are solved numerically by minimizing the error function. In this paper, with data from numerical simulations and field measurements as input, we evaluate four computational methods for minimization (optimization) for their efficiency and accuracy on solutions, and illustrate impact of bio-optical models on the retrievals. The four optimization routines are the Levenberg-Marquardt (LM), the Generalized Reduced Gradient (GRG), the Downhill Simplex Method (Amoeba), and the Simulated Annealing-Downhill Simplex (i.e. SA + Amoeba, hereafter abbreviated as SAA). The Garver-Siegel-Maritorena SOA model is used as a base to test these computational methods. It is observed that 1) LM is the fastest method, but SAA has the largest number of valid retrievals; 2) the quality of final solutions are strongly influenced by the forms of spectral models (or eigen functions); and 3) dynamically-varying eigen functions are necessary to obtain smaller errors for both reflectance spectrum and retrievals. Results of this study provide helpful guidance for the selection of a computational method and spectral models if an SOA scheme is to be used to process ocean color images. © 2013 Optical Society of America. Source


Gao Y.,Tsinghua National Laboratory for Information Sciences and Technology | Gao Y.,National University of Singapore | Wang M.,Hefei University of Technology | Ji R.,Xiamen University | And 3 more authors.
IEEE Transactions on Industrial Electronics | Year: 2014

In view-based 3-D object retrieval, each object is described by a set of views. Group matching thus plays an important role. Previous research efforts have shown the effectiveness of Hausdorff distance in group matching. In this paper, we propose a 3-D object retrieval scheme with Hausdorff distance learning. In our approach, relevance feedback information is employed to select positive and negative view pairs with a probabilistic strategy, and a view-level Mahalanobis distance metric is learned. This Mahalanobis distance metric is adopted in estimating the Hausdorff distances between objects, based on which the objects in the 3-D database are ranked. We conduct experiments on three testing data sets, and the results demonstrate that the proposed Hausdorff learning approach can improve 3-D object retrieval performance. © 2013 IEEE. Source


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. Source


Zhen L.,Xiamen University
Laser Physics | Year: 2013

The split pulse or multi-peak pulse is a unique phenomenon in actively Q-switched fiber lasers. The dynamics of generating the split pulse has been debated with many theories. In this paper, a numerical model is set up to investigate the nature of the split pulse by analyzing the distribution and evolution of the signal and inverted population along the fiber. The impacts of pumping power, fiber length and rise time of the modulator are shown. Based on the numerical simulation, the mechanism is concluded on, and methods for controlling the shape of the pulse to form a narrower high-power split pulse are proposed. © 2013 Astro Ltd. Source


Luo S.,Xiamen University
International Journal of Modern Physics A | Year: 2014

If three standard neutrinos mix with other degree of freedoms like sterile neutrinos, no matter how heavy the sterile neutrino masses are, it could result in the unitarity violation in the MNSP matrix. Nevertheless, the unitarity violation induced by the existence of light or heavy sterile neutrinos can have very different effects on neutrino oscillations, we call the former case direct unitarity violation and the later case the indirect unitarity violation. We will explain in this paper the difference of these two kinds of unitarity violations, then focus on the possibilities of searching the unitarity violation in neutrino oscillation experiments, of which the precision reactor experiments with multiple baselines are discussed in detail. © 2014 World Scientific Publishing Company. Source


Wang J.,Xiamen University | Hu C.,Peking University | Zhang J.,Peking University
Optics Express | Year: 2014

Based on a novel phase-sieve method by in-plane interference processes, a well-designed nonperiodic nanogroove array on gold surface is proposed as a multifunctional and multi-output plasmonic meta-element (MPM) for surface plasmon polariton waves. An MPM functions as a plasmonic lens (PL) as well as a plasmonic array illuminator (PAI), and another MPM acts as two PLs with an intersection angle of π/4 are fabricated and validated by leakage radiation microscopy measurements. Our proposed scheme with implemented functionalities could promote potential applications in high density integrated optical circuits. © 2014 Optical Society of America. Source


Sun X.,Xiamen University | Sun X.,U.S. National Institutes of Health | Cai W.,University of Wisconsin - Madison | Chen X.,U.S. National Institutes of Health
Accounts of Chemical Research | Year: 2015

ConspectusPositron emission tomography (PET) is a radionuclide imaging technology that plays an important role in preclinical and clinical research. With administration of a small amount of radiotracer, PET imaging can provide a noninvasive, highly sensitive, and quantitative readout of its organ/tissue targeting efficiency and pharmacokinetics. Various radiotracers have been designed to target specific molecular events. Compared with antibodies, proteins, peptides, and other biologically relevant molecules, nanoparticles represent a new frontier in molecular imaging probe design, enabling the attachment of different imaging modalities, targeting ligands, and therapeutic payloads in a single vector.We introduce the radiolabeled nanoparticle platforms that we and others have developed. Due to the fundamental differences in the various nanoparticles and radioisotopes, most radiolabeling methods are designed case-by-case. We focus on some general rules about selecting appropriate isotopes for given types of nanoparticles, as well as adjusting the labeling strategies according to specific applications. We classified these radiolabeling methods into four categories: (1) complexation reaction of radiometal ions with chelators via coordination chemistry; (2) direct bombardment of nanoparticles via hadronic projectiles; (3) synthesis of nanoparticles using a mixture of radioactive and nonradioactive precursors; (4) chelator-free postsynthetic radiolabeling. Method 1 is generally applicable to different nanomaterials as long as the surface chemistry is well-designed. However, the addition of chelators brings concerns of possible changes to the physicochemical properties of nanomaterials and detachment of the radiometal. Methods 2 and 3 have improved radiochemical stability. The applications are, however, limited by the possible damage to the nanocomponent caused by the proton beams (method 2) and harsh synthetic conditions (method 3). Method 4 is still in its infancy. Although being fast and specific, only a few combinations of isotopes and nanoparticles have been explored. Since the applications of radiolabeled nanoparticles are based on the premise that the radioisotopes are stably attached to the nanomaterials, stability (colloidal and radiochemical) assessment of radiolabeled nanoparticles is also highlighted.Despite the fact that thousands of nanomaterials have been developed for clinical research, only very few have moved to humans. One major reason is the lack of understanding of the biological behavior of nanomaterials. We discuss specific examples of using PET imaging to monitor the in vivo fate of radiolabeled nanoparticles, emphasizing the importance of labeling strategies and caution in interpreting PET data. Design considerations for radiolabeled nanoplatforms for multimodal molecular imaging are also illustrated, with a focus on strategies to combine the strengths of different imaging modalities and to prolong the circulation time. © 2015 American Chemical Society. Source


Zhou Y.,University of Wyoming | Zhou Y.,Xiamen University | Zhou J.,University of Wyoming
Journal of Physical Chemistry C | Year: 2012

The interaction between Ni and ceria was investigated under ultrahigh vacuum conditions using model Ni/ceria systems consisting of Ni nanoparticles vapor-deposited on well-ordered CeO x(111) (1.5 < x < 2) thin films grown on Ru(0001). As indicated by X-ray photoelectron spectroscopy studies, metallic Ni is the only species present on the reduced ceria. Ni 0 is the predominate species observed upon deposition of a submonolayer of Ni on CeO 2 at 300 K. However, a small amount of Ni is oxidized to Ni 2+. A decreased ratio of Ni 2+ to Ni 0 was observed with further increase of Ni coverage. Oxidation of Ni on CeO 2 can be facilitated by annealing as well as by depositing Ni at 500 K. Scanning tunneling microscopy studies show that Ni forms two-dimensional particles on ceria at room temperature, which suggests a strong Ni-ceria interaction. Upon deposition at 500 K, metallic Ni particles as well as NiO particles can be formed on the reduced and oxidized ceria, respectively. NiO particles exhibit a flatter particle shape than that of Ni particles. Our results can be explained by thermodynamics as well as by previous computational studies. © 2012 American Chemical Society. Source


Luo S.,Xiamen University | Xing Z.-Z.,CAS Institute of High Energy Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

The recent observation of the smallest neutrino mixing angle θ 13 in the Daya Bay and RENO experiments motivates us to examine whether θ 139° at the electroweak scale can be generated from θ 13=0° at a superhigh-energy scale via the radiative corrections. We find that it is difficult but not impossible in the minimal supersymmetric standard model, and a relatively large θ 13 may have some nontrivial impacts on the running behaviors of the other two mixing angles and CP-violating phases. In particular, we demonstrate that the CP-violating phases play a crucial role in the evolution of the mixing angles by using the one-loop renormalization-group equations of the Dirac or Majorana neutrinos in the minimal supersymmetric standard model. We also take the correlative neutrino mixing pattern with θ 1235. 3°, θ 23=45°, and θ 139.7° at a presumable flavor symmetry scale as an example to illustrate that the three mixing angles can receive comparably small radiative corrections and thus evolve to their best-fit values at the electroweak scale if the CP-violating phases are properly adjusted. © 2012 American Physical Society. Source


Wang T.,South China University of Technology | Lin B.,Minjiang University | Lin B.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2014

China has become a net importer of natural gas as a result of rapidly increasing consumption in recent years. A production peak would exist since natural gas is an exhaustible resource. As conventional natural gas production peak approaches, the development of unconventional natural gas is attracting increasing attention. China's unconventional natural gas reserves are abundant, but exploration is still in its infancy stage. Thus, with the increasing quest for low-carbon development and China's natural gas price reform, studying the impacts of unconventional gas development on China's natural gas supply and price reform under different scenarios has practical significance. In this paper we predict China's natural gas production trends in different scenarios and forecast natural gas demand. This paper concludes that the exploitation of unconventional natural gas will greatly improve China's annual natural gas production, and delay the production peak year. This is important for China's natural gas supply security as it can decrease dependence on imported gas. Furthermore, as the cleanest fossil fuel, it will enable more time and space for renewable energy development given the many costs and controversies surrounding its development in China. © 2014 Elsevier Ltd. Source


Chen L.,Xiamen University | Romero J.,University of Glasgow | Romero J.,University of Strathclyde
Optics Express | Year: 2012

Hardy's nonlocality proof is considered as "the best version of Bell's theorem". We report an experimental implementation of this by measuring the orbital angular momentum (OAM) of entangled twisted photon pairs. Two advantages arise from using twisted photons. First, the limited OAM spectrum generated by parametric down-conversion provides a natural set of OAM non-maximally entangled states with selective degrees of entanglement. Second, the measurement of any non-trivial superposition of OAM states can be conveniently done with spatial light modulators. We measure states that are defined on asymmetric OAM Bloch spheres and show results which are incompatible with local realism. © 2012 Optical Society of America. Source


Li S.-L.,Xiamen University | Tang H.-Y.,Changsha Institute of Mining Research
Yantu Gongcheng Xuebao/Chinese Journal of Geotechnical Engineering | Year: 2010

Experiments on acoustic emission (AE) characteristics of full-regime rock failure are carried out with stiffness test machine (MTS) under uniaxial loading, cyclic loading-unloading conditions to obtain the relations of stress-strain, stress-time-accumulative counts of AE, stress-time-AE rates. Based on the test results, the AE characteristics of loading process, unloading and reloading of loading-unloading process are analyzed. The results show that AE phenomena can apparently appear during the process of unloading. When being reloaded under the stress level not more than 50% of the peak stress, there are less or little AE counts occurring as long as the stress level is not more than the previous loading stress level, that means the Kaiser effect occurs. While reloading is made again on the stress-level of over 60% of the peak stress, there occurs obviously AE events, that is so-called the Felicity phenomenon. Rock samples show a large amount of AE events in the post-peak region for both loading and loading-unloading processes. And the results also show that there exists a relatively tranquil period phenomenon of AE for all samples of the style of AE abruptly increasing during middle stress stage. Source


Huo H.,University of Marburg | Fu C.,University of Marburg | Harms K.,University of Marburg | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Journal of the American Chemical Society | Year: 2014

A metal-coordination-based high performance asymmetric catalyst utilizing metal centrochirality as the sole element of chirality is reported. The introduced substitutionally labile chiral-at-metal octahedral iridium(III) complex exclusively bears achiral ligands and effectively catalyzes the enantioselective Friedel-Crafts addition of indoles to α,β- unsaturated 2-acyl imidazoles (19 examples) with high yields (75%-99%) and high enantioselectivities (90-98% ee) at low catalyst loadings (0.25-2 mol %). Counterintuitively, despite its substitutional lability, which is mechanistically required for coordination to the 2-acyl imidazole substrate, the metal-centered chirality is maintained throughout the catalysis. This novel class of reactive chiral-at-metal complexes will likely be of high value for a large variety of asymmetric transformations. © 2014 American Chemical Society. Source


Chen F.,Xiamen University | Cao Y.,Air Force Research Lab | Ren W.,University of California at Riverside
IEEE Transactions on Automatic Control | Year: 2012

We present a distributed discontinuous control algorithm for a team of agents to track the average of multiple time-varying reference signals with bounded derivatives. We use tools from nonsmooth analysis to analyze the stability of the system. For time-invariant undirected connected network topologies, we prove that the states of all agents will converge to the average of the time-varying reference signals with bounded derivatives in finite time provided that the control gain is properly chosen. The validity of this result is also established for scenarios with switching undirected connected network topologies. For time-invariant directed network topologies with a directed spanning tree, we show that all agents will still reach a consensus in finite time, but the convergent value is generally not the average of the time-varying reference signals with bounded derivatives. Simulation examples are presented to show the validity of the above results. © 1963-2012 IEEE. Source


Chen Z.W.,Xiamen University | Chen Z.W.,Hong Kong Polytechnic University | Xu Y.L.,Hong Kong Polytechnic University | Wang X.M.,CSIRO
Journal of Structural Engineering (United States) | Year: 2012

Long-span suspension bridges carrying both highway and railway have been built in wind-prone regions. The estimation of fatigue damage of such bridges under the long-term combined action of railway, highway, and wind loading represents a challenging task in consideration of randomness in multiple types of loading. This study presents a framework for fatigue reliability analysis of multiloading long-span suspension bridges equipped with structural health monitoring systems (SHMS), and the Tsing Ma suspension bridge in Hong Kong is taken as a case study. A limit-state function in the daily sum of m-power stress ranges is first defined for fatigue reliability analysis. Probabilistic models of railway, highway, and wind loading are established on the basis of the measurement data acquired from the SHMS. The daily stochastic stress responses induced by the multiple types of loading are simulated at the fatigue-critical locations of the bridge deck by using the finite-element method and Monte Carlo simulation (MCS) together with the loading probabilistic models established. The probability distribution of the daily sum of m-power stress ranges is estimated on the basis of the daily stochastic stress responses. The probability distribution of the sum of m-power stress ranges for a given time period is then evaluated in consideration of future traffic growth patterns. Finally, the fatigue failure probabilities of the bridge at the fatigue-critical locations are calculated for different time periods. The results demonstrate that the health condition of the Tsing Ma Bridge at the end of its design life will be satisfactory under current traffic conditions without growth but that attention should be paid to future traffic growth because it may lead to a much greater fatigue failure probability. © 2012 American Society of Civil Engineers. Source


Ouyang X.,East China Normal University | Lin B.,Xiamen University | Lin B.,Minjiang University
Renewable and Sustainable Energy Reviews | Year: 2015

Both energy consumption and the growth of carbon dioxide (CO2) emissions in China are attributed to the industrial sector. Energy conservation and CO2 emissions reduction in China's industrial sector is decisive for achieving a low-carbon transition. We analyze the change of energy-related CO2 emissions in China's industrial sector from 1991 to 2010 based on the Logarithmic Mean Divisia Index (LMDI) method. Results indicate that industrial activity is the major factor that contributes to the increase of industrial CO2 emissions while energy intensity is the major contributor to the decrease of CO2 emissions. Industry size shows a varying trend interchanging intervals of growth along the study period. Moreover, both energy mix and carbon intensity of energy use have negative effects on the increase of CO2 emissions. The cointegration method is adopted to further explore determinants of CO2 emissions in China's industrial sector. Results show that there exists a long-run relationship between industrial CO2 emissions and affecting factors such as CO2 emissions per unit of energy consumption, industrial value added, labor productivity and fossil fuel consumption. China's industrial CO2 emissions are mainly attributed to the coal-dominated energy structure. Policy suggestions are thus provided to reduce industrial CO2 emissions in China. © 2015 Elsevier Ltd. All rights reserved. Source


Zhu J.,Nanjing University of Aeronautics and Astronautics | Zhong X.,Michigan State University | Shu C.-W.,Brown University | Qiu J.,Xiamen University
Journal of Computational Physics | Year: 2013

In this paper we generalize a new type of limiters based on the weighted essentially non-oscillatory (WENO) finite volume methodology for the Runge-Kutta discontinuous Galerkin (RKDG) methods solving nonlinear hyperbolic conservation laws, which were recently developed in [32] for structured meshes, to two-dimensional unstructured triangular meshes. The key idea of such limiters is to use the entire polynomials of the DG solutions from the troubled cell and its immediate neighboring cells, and then apply the classical WENO procedure to form a convex combination of these polynomials based on smoothness indicators and nonlinear weights, with suitable adjustments to guarantee conservation. The main advantage of this new limiter is its simplicity in implementation, especially for the unstructured meshes considered in this paper, as only information from immediate neighbors is needed and the usage of complicated geometric information of the meshes is largely avoided. Numerical results for both scalar equations and Euler systems of compressible gas dynamics are provided to illustrate the good performance of this procedure. © 2013 Elsevier Inc. Source


Velmurugan J.,Queens College, City University of New York | Zhan D.,Queens College, City University of New York | Zhan D.,Xiamen University | Mirkin M.V.,Queens College, City University of New York
Nature Chemistry | Year: 2010

In this Article we have used new approaches to investigate a well-known chemical process, the propagation of electrochemical signals through a thin glass membrane. This process, which has been extensively studied over the last century, is the basis of the response of a potentiometric glass pH sensor; however, no amperometric glass sensors have yet been reported because of its high ohmic resistance. Voltammetry at nanoelectrodes has revealed that water molecules can diffuse through nanometre-thick layers of dry glass and undergo oxidation/reduction at the buried platinum surface. After soaking for a few hours in an aqueous solution, voltammetric waves of other redox couples, such as Ru(NH3)6 3+/2+, could also be obtained at the glass-covered platinum nanoelectrodes. This behaviour suggests that the nanometre-thick insulating glass sheath surrounding the platinum core can be largely converted to hydrated gel, and electrochemical processes occur at the platinum/hydrogel interface. Potential applications range from use in nanometre-sized solid-state pH probes and determination of the water content in organic solvents to glass-modified voltammetric sensors and electrocatalysts. © 2010 Macmillan Publishers Limited. All rights reserved. Source


Li C.C.,Hunan University | Zheng Y.P.,Xiamen University | Wang T.H.,Hunan University
Journal of Materials Chemistry | Year: 2012

In this work, we reported several kinds of highly stable, effective mesoporous Au/TiO 2 sphere-based solid acid catalysts with large specific surface areas and good monodispersity in the reaction medium. In this process, monodisperse titanium glycolate spheres were first formed by an antisolvent precipitation route, and were then converted to mesoporous TiO 2 by in situ hydrolysis under hydrothermal conditions. The resultant uniform TiO 2 spheres were subsequently functionalized with sulfate anions at different temperatures or incorporated with tungstophosphoric acid (TPA); the solid acid catalysts were thus fabricated. In particular, our monodisperse spherical catalysts with large specific surface area have shown remarkable performance in a wide range of acid-catalyzed reactions such as Friedel-Crafts alkylation, esterification and hydrolysis of acetate. The TiO 2-based catalysts could be separated and reused showing no deactivation. © 2012 The Royal Society of Chemistry. Source


Luo Y.,Huaqiao University | Liu P.,Huaqiao University | Liao M.,Xiamen University
International Journal on Smart Sensing and Intelligent Systems | Year: 2014

Because of not needing training samples and performing the classification just according to the inherent similarity of data in the multidimensional space, unsupervised classification method now gets more and more attention by remote sensing data analyst. Duo to the special growth environment of mangroves, field measurements is difficult to be done to obtain training samples. Therefore unsupervised method provides a good adjunct way for the classification of mangroves remote sensing image. This paper presents an immune network based unsupervised classification method, which is not necessary to define complex objective function. By arbitrarily selecting a certain number of data to be training samples, the proposed algorithm mines the prior knowledge of the samples and selects a few samples to constitute the initial nodes of immune network. After the evolutionary of the immune network, the clustering results are obtained, combined with nearest neighbor classification mechanism, the classification is performed. The experiment results show that the proposed algorithm has better overall stability and can get better clustering result for mangroves remote sensing image than traditional clustering methods. Source


Cheng L.,Cleveland Clinic | Huang Z.,Cleveland Clinic | Zhou W.,Cleveland Clinic | Wu Q.,Cleveland Clinic | And 10 more authors.
Cell | Year: 2013

Glioblastomas (GBMs) are highly vascular and lethal brain tumors that display cellular hierarchies containing self-renewing tumorigenic glioma stem cells (GSCs). Because GSCs often reside in perivascular niches and may undergo mesenchymal differentiation, we interrogated GSC potential to generate vascular pericytes. Here, we show that GSCs give rise to pericytes to support vessel function and tumor growth. In vivo cell lineage tracing with constitutive and lineage-specific fluorescent reporters demonstrated that GSCs generate the majority of vascular pericytes. Selective elimination of GSC-derived pericytes disrupts the neovasculature and potently inhibits tumor growth. Analysis of human GBM specimens showed that most pericytes are derived from neoplastic cells. GSCs are recruited toward endothelial cells via the SDF-1/CXCR4 axis and are induced to become pericytes predominantly by transforming growth factor β. Thus, GSCs contribute to vascular pericytes that may actively remodel perivascular niches. Therapeutic targeting of GSC-derived pericytes may effectively block tumor progression and improve antiangiogenic therapy. © 2013 Elsevier Inc. Source


Study Design. Descriptive study, stratified sampling. Objective. Using dynamic computed tomographic perfusion (CTP) to explore the age-related distribution patterns of the microcirculation perfusion in the vertebral marrow, the vertebral bone mineral density (BMD), and the intervertebral discal degeneration (IDD) further to discuss the possible causation between them. Summary of Background Data. A latest viewpoint deemed that reduced blood supply of the vertebral marrow was correlated with an increased incidence of IDD and loss of BMD. However, the causative relationship between them needs more investigation. Methods. One hundred eighty-six general people were randomly enrolled by stratified sampling and grouped by age: 15 years or less, 16 to 25 years, 26 to 35 years, 36 to 45 years, 46 to 55 years, 56 to 65 years, 66 to 75 years, and 76 years or more. Both CTP and BMD of the third and fourth lumbar vertebral marrow were measured, and the IDD incidence of the third-fourth vertebrae was assessed. The temporal-spatial distribution patterns of the age-related changes of CTP, BMD, and IDD were described, and the correlations between them were calculated. Results. Microcirculatory perfusion of the vertebral marrow developed to maturate by 25 years, maintained stable at 35 years, and then declined by age after 35 years. BMD grew to a peak phase in 26 to 45 years and then dropped by years. However, IDD presented a sudden increase after 45 years of age. CTP (blood flow [r = 0.806], blood volume [r = 0.685], and permeability [r = 0.619]) showed strong positive correlations and CTP (time to peak [r = - 0.211], mean transit time [r = - 0.598]) showed negative correlations with BMD. Meanwhile, CTP (blood flow [r = - 0.815], blood volume [r = - 0.753], and permeability [r = - 0.690]) had strong negative correlations and CTP (time to peak [r = 0.323] and mean transit time [r = 0.628]) had positive correlations with the incidence of IDD. Conclusion. Aging-related decrease of the microcirculatory perfusion of the lumbar vertebral marrow preceded the loss of BMD and the onset of IDD, indicating their possible causal relationship. Copyright © 2015 Wolters Kluwer Health, Inc. Source


To S.K.Y.,University of Hong Kong | Zeng J.-Z.,Xiamen University | Wong A.S.T.,University of Hong Kong
Expert Opinion on Therapeutic Targets | Year: 2012

The orphan nuclear receptor Nur77 (also known as NR4A1, NGFIB, TR3, TIS1, NAK-1, or N10) is a unique transcription factor encoded by an immediate early gene. Nur77 signaling is deregulated in many cancers and constitutes an important molecule for drug targeting. Areas covered: Nur77 as a versatile transcription factor that displays distinct dual roles in cell proliferation and apoptosis. In addition, several recent insights into Nur77's non-genomic signaling through its physical interactions with various signaling proteins and its phosphorylation-dependent regulation will be highlighted. The possible mechanisms by which Nur77 supports carcinogenesis and specific examples in different human cancers will be summarized. Different approaches to target Nur77 using mimetics, natural products, and synthetic compounds are also described. Expert opinion: These latest findings shed light on the novel roles of Nur77 as an exploitable target for new cancer therapeutics. Further work which focuses on a more complete understanding of the Nur77 interactome as well as how the different networks of Nur77 functional interactions are orchestrated in a stimulus or context-specific way will aid the development of more selective, non-toxic approaches for targeting Nur77 in future. © 2012 Informa UK, Ltd. Source


Hong W.,Xiamen University | Hong W.,Institute of Molecular and Cell Biology | Guan K.-L.,University of California at San Diego
Seminars in Cell and Developmental Biology | Year: 2012

The Hippo signaling pathway was initially defined by genetic studies in Drosophila to regulate tissue growth and organ size [1,2]. This pathway is highly conserved in mammals and dysregulation of the Hippo pathway has been implicated in human cancer. Although the exact extracellular signal that controls the Hippo pathway is currently unknown, compelling evidence supports a critical role of the Hippo pathway in cell contact inhibition, which is a property commonly lost in cancer cells. Many molecules, such as the merlin tumor suppressor protein, have been identified as regulating the activity of the core Hippo pathway components [1,2]. Acting downstream are two key transcription co-activators, YAP and TAZ, which mediate the major gene regulation and biological functions of the Hippo pathway. This article will focus on the physiological function and molecular regulation of YAP/TAZ and its Drosophila homolog Yki. © 2012 Elsevier Ltd. Source


Chen G.C.,State Oceanic Administration | Chen G.C.,City University of Hong Kong | Tam N.F.Y.,City University of Hong Kong | Ye Y.,Xiamen University
Soil Biology and Biochemistry | Year: 2012

Marine ecosystems are a known net source of greenhouse gases emissions but the atmospheric gas fluxes, particularly from the mangrove swamps occupying inter-tidal zones, are characterized poorly. Spatial and seasonal fluxes of nitrous oxide (N 2O) and carbon dioxide (CO 2) from soil in Mai Po mangrove swamp in Hong Kong, South China and their relationships with soil characteristics were investigated. The N 2O fluxes averaged from 32.1 to 533.7μgm -2h -1 and the CO 2 fluxes were between 10.6 and 1374.1mgm -2h -1. Both N 2O and CO 2 fluxes in this swamp showed large spatial and seasonal variations. The fluxes were higher at the landward site than the foreshore bare mudflat, and higher fluxes were recorded in warm, rather than cold, seasons. The landward site had the highest content of soil organic carbon (OC), total Kjeldahl nitrogen (TKN), nitrate (NO 3 --N) and total phosphorus (TP), while the bare mudflat had the highest ammonium nitrogen (NH 4 +-N) concentration and soil denitrification potential activity. The N 2O flux was related, positively, to CO 2 flux. Soil NO 3 --N and TP increased N 2O flux, while soil OC and TP concentrations contributed to the CO 2 flux. The results indicated that the Mai Po mangrove swamp emitted significant amounts of greenhouse gases, and the N 2O emission was probably due to soil denitrifcation. © 2012 Elsevier Ltd. Source


Ouyang X.,East China Normal University | Lin B.,Minjiang University | Lin B.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2014

Subsidies to fossil-fuel consumption have made Chinas energy system fragile and unsustainable. It is necessary for China to reform fossil-fuel subsidies and reflect the resource cost and environmental cost in energy prices. Considering the life-cycle external costs, this paper estimates the scale of fossil-fuel subsidy and the true cost of renewable energy in 2010 and evaluates impacts of increasing renewable energy subsidies and phasing out fossil fuel subsidies on macro-economy and energy system in China based on scenario analysis. Simulation results show that the negative impacts on economic growth can be reduced from 4.460% to 0.432%, if only 10% of fossil fuel subsidies were removed. Increasing subsidies for renewable energy has positive impacts on macroeconomic variables. Although the economic benefits per unit of subsidies for renewable energy are lower than those for fossil fuels by 0.06-0.19 CNY, the revenue gap can be narrowed by shifting more subsidies from fossil fuels to renewables. Increasing subsidies for renewable energy helps optimize Chinas energy system in three ways: the first is making energy consumption structure cleaner; the second is improving energy efficiency; and the third is addressing the problem of imbalanced distribution and consumption of energy. © 2014 Elsevier Ltd. Source


Zhou B.,Nihon University | Kobayashi A.,Nihon University | Cui H.-B.,RIKEN | Long L.-S.,Xiamen University | And 2 more authors.
Journal of the American Chemical Society | Year: 2011

Guest water molecules confined in channels of porous coordination polymer crystals [Ln2Cu3(IDA)6]·nH2O (Ln = La, Nd, Sm, Gd, Ho, Er; IDA = [NH(CH2COO)2] 2-; n ≈ 9) exhibited large dielectric constants (ε) and antiferroelectric behaviors at high temperatures (e.g., ε(Sm) ≈ 1300 at 400 K). In addition, plots of the temperature dependence of ε showed broad peaks at ∼170 K, below which ε became very small. These puzzling temperature dependences of ε are consistent with the results of molecular dynamics simulations, suggesting the "freezing of thermal motion" of water molecules at ∼170 K. © 2011 American Chemical Society. Source


A micro surface tension pump is a new type of low-cost, built-in, all-glass, microfluidic pump on a glass microchip fabricated by one-step glass etching. However, geometric minimization and optimization for practical use are challenging. Here, we report a one-square-millimeter, built-in, all-glass pump controlled by two-way digital gas pressure. The pump consists simply of two joint chambers and a piston between two gas control channels. It does not require pre-perfusion for initialization, and can immediately begin to run when a liquid enters its inlet channel. It is also more reliable than conventional micro pumps for practical use due to its ability to restart after the formation of a blocking bubble, which can serve as a valuable troubleshooting procedure. Its volumetric pump output was 0.5-0.7 nL· s-1 under a pump head pressure of 300 Pa. © 2016 by the authors. Source


Yu W.,Xiamen University | Li X.,Louisiana State University
Computer Graphics Forum | Year: 2014

This paper proposes an effective framework to compute the visibility guarding and star decomposition of 3D solid shapes. We propose a progressive integer linear programming algorithm to solve the guarding points that can visibility cover the entire shape; we also develop a constrained region growing scheme seeded on these guarding points to get the star decomposition. We demonstrate this guarding/decomposition framework can benefit graphics tasks such as shape interpolation and shape matching/retrieval. © 2011 The Author(s). Source


Zhang Z.,Xiamen University
Nonlinear Analysis: Real World Applications | Year: 2012

In this paper, we give a rigorous mathematical analysis for a third order nonlinear boundary value problem. The boundary value problem can be applied to steady free convection around a vertical impermeable flat plate in a fluid-saturated porous medium, or steady flow of a power-law fluid induced by impermeable stretching walls in the frame of boundary layer approximation. We establish the uniqueness, existence and nonexistence of (normal) concave solutions or generalized concave solutions to the problem, and obtain some results about boundedness and asymptotic behavior of the (normal) concave solution or the generalized concave solution. © 2012 Elsevier Ltd. All rights reserved. Source


A novel quasi-resonant bridge modular switchedcapacitor converter (BMSCC) is proposed in the paper. The main merit is that its resonant circuit has high stability and simplicity, resulting from the employment of the stray inductance distributed in the circuit as a collective resonant inductor. Accordingly, the current spike during switching operation is removed due to zerocurrent- switching (ZCS) realization. Another distinct merit is that the proposed converter features symmetric construction.With this kind of construction, the voltage ripple of charge/pump capacitors can be cancelled out with each other and then output voltage ripple will be largely reduced. Thus, it is unnecessary to use a bulky capacitor to reduce output voltage ripple. Compared with conventional SCCs, at the same conversion ratio, the BMSCC with symmetric construction requires fewer switches and capacitors with lower voltage stress, so as to cut the size and cost and promote the power destiny further. It is also noteworthy that the symmetric construction character assures that the two symmetric parts can work independently under a simplified control strategy. In addition, the modular configuration contributes to convenient voltage extension conveniently. The simulation and experimental results of a 100Wprototype with a voltage conversion ratio of eight validate the principle and features of this topology. © 1986-2012 IEEE. Source


Ouyang X.,East China Normal University | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy and Buildings | Year: 2014

Electricity consumption of the Chinese building materials industry accounted for 8.4% of industrial and 6.2% of national electricity usage in 2011. The purpose of this paper is to estimate the future electricity intensity and conservation potential of the Chinese building materials industry. This paper adopts a cointegration method to establish a long-run equilibrium relationship between electricity intensity and factors including technology, power tariff, enterprise scale and value-added per worker. Electricity conservation potential in the Chinese building materials industry is predicted to be 90.5 billion kW h in 2020 under the moderate scenario, which is more than the total electricity consumption of Malaysia in 2007; and 150.9 billion kW h under the advanced scenario, which is more than the total electricity consumption of Saudi Arabia in 2005. Conserved electricity in building materials industry would account for 1.2% and 2.0% of national electricity consumption under the two scenarios, respectively. More importantly, we find that the electricity intensity gap between Chinese and the world's leading building materials industries could be significantly narrowed by 2020 if aggressive energy conservation policies were implemented. Finally, based on the results of our study, future policy priorities and directions are suggested. © 2014 Elsevier B.V. All rights reserved. Source


Ding C.,Xiamen University
International Journal of Bifurcation and Chaos | Year: 2012

This paper deals with intertwined basins of attraction for dynamical systems in a metric space. After giving a general definition of intertwining property, which is preserved by a topological equivalence between dynamical systems, we present a sufficient condition to guarantee the existence of intertwined basins for dynamical systems in ℝ n. © 2012 World Scientific Publishing Company. Source


Chen M.,Xiamen University | Chen M.,Shandong University
Nonlinear Analysis: Real World Applications | Year: 2012

We prove that the maximum norm of velocity gradients controls the possible breakdown of smooth (strong) solutions for the 3-dimensional viscous, compressible micropolar fluids. More precisely, if a solution of the system is initially regular and loses its regularity at some later time, then the loss of regularity implies the growth without the bound of the velocity gradients as the critical time approaches. Our result is a generalization of Huang et al. (2011) [13] from viscous barotropic flows to the viscous, compressible micropolar fluids. In addition, initial vacuum states are also allowed in our result. © 2011 Elsevier Ltd. All rights reserved. Source


Weng Z.-H.,Xiamen University
Progress in Electromagnetics Research Symposium | Year: 2012

J. C. Maxwell was the first to adopt the quaternion and the vector to describe the electromagnetic theory. It inspired the scholars to use the quaternion and the octonion to depict the electromagnetic and gravitational theories. On the other hand, A. Einstein adopted the tensor and the curved space to picture the property of gravitational field. It encouraged the scholars to depict the features of electromagnetic fields and gravitational fields by means of the curved quaternion space and the curved octonion space. The orthogonality of two quaternions can be defined via the scalar product of quaternions. The parallel transport and the covariant derivation can be defined in the curved quaternion space, and they can be applied to describe the property of gravitational fields in the curved quaternion space. Similarly the orthogonality of two octonions can be defined by the scalar product of octonions. And the parallel transport and the covariant derivative can be defined in the curved octonion space, and then they can be applied to describe the property of electromagnetic fields and gravitational fields in the curved octonion space simultaneously. The results reveal that the connection coefficient and the curvature of the curved octonion space can impact directly the field strength and the field source etc in electromagnetic fields and gravitational fields. Source


Dorr M.,University of Marburg | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Current Opinion in Chemical Biology | Year: 2014

This article reviews recent advances in the design and discovery of inert metal complexes as protein binders. In these metal-based probes or drug candidates, the metal is supposed to exert a purely structural role by organizing the coordinating ligands in the three dimensional space to achieve a shape and functional group complementarity with the targeted protein pockets. Presented examples of sandwich, half-sandwich and octahedral d6-metal complexes reinforce previous perceptions that metal complexes are highly promising scaffolds for the design of small-molecule protein binders and complement the molecular diversity of organic chemistry by opening untapped chemical space. © 2014 Elsevier Ltd. Source


Zhang X.,Xiamen University
Journal of Control Theory and Applications | Year: 2011

The sufficient conditions of delay-dependent exponential stability for switched systems and robust exponential stability for uncertain switched systems with two time-delays are presented by using average dwell time method and free-weighting matrix method. The interaction between different time-delays is considered. The sufficient conditions do not need that every subsystem is stable. The designed methods of the switching law are also given. The sufficient conditions are given in the form of linear matrix inequalities that can be solved easily. The result is proven to be valid by the simulation at last. © 2011 South China University of Technology, Academy of Mathematics and Systems Science, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg. Source


Pang X.,Georgia Institute of Technology | Wan C.,Georgia Institute of Technology | Wang M.,Georgia Institute of Technology | Wang M.,Xiamen University | Lin Z.,Georgia Institute of Technology
Angewandte Chemie - International Edition | Year: 2014

Janus structures, named after the ancient two-faced Roman god Janus, comprise two hemistructures (e.g. hemispheres) with different compositions and functionalities. Much research has been carried out over the past few years on Janus structures because of the intriguing properties and promising potential applications of these unusually shaped materials. This Review discusses recent progress made in the synthesis, properties, and applications of strictly biphasic Janus structures possessing symmetrical structures but made of disparate materials. Depending on the chemical compositions, such biphasic structures can be categorized into soft, hard, and hybrid soft/hard Janus structures of different architectures, including spheres, rodlike, disclike, or any other shape. The main synthetic routes to soft, hard, and hybrid soft/hard Janus structures are summarized and their unique properties and applications are introduced. The perspectives for future research and development are also described. Best of both worlds: Janus structures comprise two hemistructures with different compositions and functionalities. This Review summarizes the synthetic routes to soft, hard, and hybrid soft/hard Janus structures, and discusses their properties and applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Zhang T.H.,Soochow University of China | Liu X.Y.,Xiamen University | Liu X.Y.,National University of Singapore
Chemical Society Reviews | Year: 2014

In the last few decades, the controlled colloidal assembly was adopted as a new modelling technology for the study of the crystallization mechanism. In colloidal systems, the movement of particles is slow enough to follow and the particle dynamics can be monitored at the single-particle level using normal optical microscopes. So far, the studies of colloidal crystallization have produced a number of insights, which have significantly improved our understanding of crystallization. In this review, we summarize the recent advances in understanding the mechanism of crystallization, which were achieved using colloidal model systems, i.e., the kinetics of nucleation, growth and defect formation. Such model systems allow us to not only visualize some "atomic" details of nucleation and surface processes of crystallization, but also quantify previous models to such an extent that has never been achieved before by other approaches. In the case of nucleation, the quantitative observation of the kinetic process was made at the single-particle level; the results include the ideal case and the deviations from classical theories. The deviations include multi-step crystallization, supersaturation-driven structural mismatch nucleation, defect creation and migration kinetics, surface roughening, etc. It can be foreseen that this approach will become a powerful tool to study the fundamental process of crystallization and other phase transitions. This journal is © the Partner Organisations 2014. Source


Chen B.-Y.,National Ilan University | Wang Y.-M.,National Ilan University | Ng I.-S.,Xiamen University
Bioresource Technology | Year: 2011

This first-attempt study quantitatively explored interactive characteristics of bioelectricity generation and dye decolorization in air-cathode single-chamber microbial fuel cells (MFCs) using indigenous Proteus hauseri ZMd44. After approx. 15 cycles (30. days) acclimatization in dye-bearing cultures, P. hauseri could express its stable capability of simultaneous bioelectricity generation and color removal (SBP&CR) in MFCs. Evidently, appropriate acclimation strategy for formation of the electrochemically active anodic biofilm played a crucial role to enhance the performance of SBP&CR in MFCs. Gradually increased supplementations of C.I. reactive blue 160 resulted in progressively decreased decay rate of bioelectricity generation. That is, a dye decolorized in a faster rate would result in a lower capability for bioelectricity generation and vice versa. In addition, a reduced dye with less toxicity potency (e.g., 2-aminophenol) might work as a redox mediator of electron transport to anodic biofilm for bioelectricity generation in MFCs. © 2010 Elsevier Ltd. Source


Wei D.,CNRS Non-Linear Institute of Nice | Wei D.,Xiamen University | Residori S.,CNRS Non-Linear Institute of Nice | Bortolozzo U.,CNRS Non-Linear Institute of Nice
Optics Letters | Year: 2012

Optical phase conjugation and slow light are obtained in dye-doped chiral nematics via degenerate four-wave mixing. The creation of the light-induced dynamical grating is described and the amplitude of the phase-conjugate wave is shown to follow the changes of the input signal, hence providing efficient distortion correction. Associated to these capabilities, slowing down of light pulses is obtained thanks to the dispersive properties of the wave mixing occurring in the cholesteric liquid crystals, opening the way to applications in interferometry and imaging through highly scattering media. © 2012 Optical Society of America. Source


Pitz R.W.,Vanderbilt University | Hu S.,Babcock and Wilcox Research Center | Wang P.,Xiamen University
Progress in Energy and Combustion Science | Year: 2014

Tubular flames are ideal for the study of stretch and curvature effects on flame structure, extinction, and instabilities. Tubular flames have uniform stretch and curvature and each parameter can be varied independently. Curvature strengthens or weakens preferential diffusion effects on the tubular flame and the strengthening or weakening is proportional to the ratio of the flame thickness to the flame radius. Premixed flames can be studied in the standard tubular burner where a single premixed gas stream flows radially inward to the cylindrical flame surface and products exit as opposed jets. Premixed, diffusion and partially premixed flames can be studied in the opposed tubular flame where opposed radial flows meet at a cylindrical stagnation surface and products exit as opposed jets. The tubular flame flow configurations can be mathematically reduced to a two-point boundary value solution along the single radial coordinate. Non-intrusive measurements of temperature and major species concentrations have been made with laser-induced Raman scattering in an optically accessible tubular burner for both premixed and diffusion flames. The laser measurements of the flame structure are in good agreement with numerical simulations of the tubular flame. Due to the strong enhancement of preferential diffusion effects in tubular flames, the theory-data comparison can be very sensitive to the molecular transport model and the chemical kinetic mechanism. The strengthening or weakening of the tubular flame with curvature can increase or decrease the extinction strain rate of tubular flames. For lean H 2-air mixtures, the tubular flame can have an extinction strain rate many times higher than the corresponding opposed jet flame. More complex cellular tubular flames with highly curved flame cells surrounded by local extinction can be formed under both premixed and non-premixed conditions. In the hydrogen fueled premixed tubular flames, thermal-diffusive flame instabilities result in the formation of a uniform symmetric petal flames far from extinction. In opposed-flow tubular diffusion flames, thermal-diffusive flame instabilities result in cellular flames very close to extinction. Both of these flames are candidates for further study of flame curvature and extinction. © 2014 Elsevier Ltd. All rights reserved. Source


Lan W.,Xiamen University | Thum C.K.,DSO National Laboratories | Chen B.M.,National University of Singapore
IEEE Transactions on Industrial Electronics | Year: 2010

This paper investigates the design of composite nonlinear-feedback (CNF) control law for a hard-disk-drive (HDD) servo system. First, a scaled nonlinear function is introduced for the CNF control law, in which a parameter is scaled by the error between the amplitude of the target reference and the initial value of the system controlled output. The closed-loop system under the scaled function has robust transient performance to the variation of the amplitude of the target reference. Then, the parameters of the selected nonlinear function are tuned by optimal tuning methods. More specifically, the parameter-tuning problem is formulated as an optimization problem, which can be solved efficiently via numerical methods. The simulation and experimental results show that the control law designed using the new approach yields excellent performance for both track seeking and track following in the HDD servo system. © 2006 IEEE. Source


Huang X.,Xiamen University | Ouyang X.,Yale University | Deng X.W.,Yale University
Current Opinion in Plant Biology | Year: 2014

Light is a pivotal environmental stimulus that promotes plant photomorphogenesis. Substantial progress has been achieved in defining the central repressors of photomorphogenesis, the CONSTITUTIVE PHOTOMORPHOGENIC/. DE-ETIOLATED/. FUSCA (COP/. DET/. FUS) loci, in the past 20 years. COP/DET/FUS proteins are well-conserved, and regulate a variety of biological processes in plants and animals. The fact that these proteins contribute to the repression of plant photomorphogenesis by regulating the ubiquitin-proteasome-dependent pathway has been well established. Recently, molecular insight has been gained into the functional diversity of COP/DET/FUS. Here, we review the current research on the roles of COP/DET/FUS, with a focus on the functional conversion of COP1 in photomorphogenesis. © 2014 Elsevier Ltd. Source


Li Z.,Tianjin University | Song G.-L.,Xiamen University | Song G.-L.,University of Queensland | Song S.,Tianjin University
Electrochimica Acta | Year: 2014

The effect of bicarbonate on biodegradation of pure magnesium in a simulated body fluid is investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, polarization curve and electrochemical impedance spectroscopy. The results show that magnesium biodegrades rapidly and non-uniformly during 27 h of immersion in four simulated body fluid solutions containing different concentrations of bicarbonate. The biodegradation rate first decreases and then increases with time. A small amount of bicarbonate in simulated body fluid has an inhibition effect on the Mg dissolution, while an overdose of bicarbonate addition activates the magnesium surface in the simulated body fluid. The interesting phenomena can be interpreted by a surface film model involving precipitation of calcium carbonate and further ionization of bicarbonate in the simulated body fluids, incorporation of calcium, carbonate and phosphate compounds in the surface film, and development of chloride-induced pitting corrosion damage on the magnesium with time. © 2013 Elsevier Ltd. Source


Chen J.,Zhejiang University | Yan X.,Zhejiang University | Zhao Q.,CAS Shanghai Institute of Organic Chemistry | Li L.,Xiamen University | Huang F.,Zhejiang University
Polymer Chemistry | Year: 2012

Highly ordered supramolecular polymer honeycomb-patterned films were fabricated successfully via the static breath figure method. The supramolecular polymer that was used to prepare these intriguing films was obtained from the self-organization of a heteroditopic monomer based on the benzo-21-crown-7/ secondary ammonium salt recognition motif. The morphologies of these microstructures were observed by scanning electron microscopy, optical microscopy and atomic force microscopy techniques. The monomer concentration plays an important role in the fabrication of these supramolecular polymer microstructures. The pore size of honeycomb-patterned films decreases with the increase of the monomer concentration from 4 wt% to 30 wt%. A microsphere (900 nm) pattern and a highly-ordered honeycomb-patterned film (2.0 μm) were obtained via the static breath figure method using acetonitrile as the solvent at concentrations of 2 wt% and 30 wt%, respectively. © 2012 The Royal Society of Chemistry. Source


Luo S.,Xiamen University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

Enlightened by the idea of the 3×3 Cabibbo-Kobayashi-Maskawa angle matrix proposed recently by Harrison, we introduce the Dirac angle matrix Φ and the Majorana angle matrix Ψ in the lepton sector for Dirac and Majorana neutrinos, respectively. We show that in the presence of CP violation, the angle matrix Φ or Ψ is entirely equivalent to the complex Maki-Nakagawa-Sakata matrix V itself, but has the advantage of being real, phase rephasing invariant, directly associated to the leptonic unitarity triangles and do not depend on any particular parametrization of V. In this paper, we further analyzed how the angle matrices evolve with the energy scale. The one-loop renormalization group equations of Φ, Ψ and some other rephasing invariant parameters are derived and a numerical analysis is performed to compare between the case of Dirac and Majorana neutrinos. Different neutrino mass spectra are taken into account in our calculation. We find that apparently different from the case of Dirac neutrinos, for Majorana neutrinos the renormalization group equation evolutions of Φ, Ψ and J strongly depend on the Majorana-type CP-violating parameters and are more sensitive to the sign of Δm312. They may receive significant radiative corrections in the minimal supersymmetric standard model with large tan β if three neutrino masses are nearly degenerate. © 2012 American Physical Society. Source


Zhang L.,Tianjin University of Technology | Xie Z.,Xiamen University | Gong J.,Tianjin University of Technology
Chemical Society Reviews | Year: 2016

Au-Pd nanostructured materials have been recognized as important heterogeneous catalysts in various reactions, due to their superior activities caused by the ensemble and ligand effects. In recent years, shape-controlled synthesis of noble metal nanocrystals (NCs) provided a brand-new insight for improving the performance of catalysts. The electronic properties and catalytic activities of Au-Pd NCs could be optimized by tuning their shape and composition engineering. This review describes recent progress in the design and synthesis of shape-controlled Au-Pd bimetallic NCs and their emerging catalytic applications. The review starts with a general discussion of various applications of Au-Pd catalysts and the significance of preparing shape-controlled Au-Pd NCs, followed by an overview of synthetic strategies for two different structures of Au-Pd bimetallic catalysts: a core-shell structure and an alloy structure. We also put forward the key factors for the preparation of Au-Pd core-shell and alloy structures. Additionally, we discussed the unique optical properties and structural effects of shape-controlled Au-Pd NCs. These recent advancements in the methodology development of Au-Pd bimetallic NCs offer numerous insights for generating Au-Pd NCs with a number of unique geometries in the future. Furthermore, the systematic synthesis of core-shell or alloy structures would provide insights for the preparation of other bimetallic NCs. © 2016 The Royal Society of Chemistry. Source


Li A.,Shandong University | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy Policy | Year: 2013

Currently, China is the largest carbon emitter mainly due to growing consumption of fossil fuels. In 2009, the Chinese government committed itself to reducing domestic carbon emissions per unit of GDP by 40-45% by 2020 compared to 2005 levels. Therefore, it is a top priority for the Chinese government to adopt efficient policy instruments to reduce its carbon intensity. Against this background, this paper develops a general equilibrium model and seeks to provide empirical contributions by comparing the potential impacts of several different policy options to reduce China's carbon emissions. The main findings are as follows. Firstly, these climate policies would affect the structure of economy and contribute to carbon emissions reduction and carbon intensity reduction. Secondly, there would be significant differences in the economic and environmental effects among different climate policies and hence, the government would trade-off among different economic objectives to overcome any potential resistances. Thirdly, there would be considerable differences in the emissions effects of absolute and intensity-based carbon emissions controls, implying that the government might adopt different climate policies for absolute or intensity-based carbon emissions controls. Looking ahead, the government should trade-off among different objectives when designing climate reforms. © 2013 Elsevier Ltd. Source


Zhang Y.,Hunan Institute of Science and Technology | Zhang Y.,Central China Normal University | Tan Z.,Xiamen University | Sun M.-B.,Hunan Institute of Science and Technology
Nonlinear Analysis: Real World Applications | Year: 2013

In this paper, we are concerned with a model arising from biology, which is a coupled hyperbolic-parabolic system. Firstly, we prove global existence of smooth solutions to the Cauchy problem without any smallness assumption on the initial data. Secondly, we prove both global existence and asymptotic behavior of smooth solutions, provided the initial data are of small H1-norm energy but possibly large Hs-norm energy. Finally, if the Hs∩ L1-norm of initial data are sufficiently small, we also establish decay rates of the global smooth solutions. These results are obtained by constructing a new nonnegative convex entropy and combining spectral analysis with energy methods. © 2012 Published by Elsevier Ltd. Source


Liu W.,Monash University | Wu W.,Monash University | Selomulya C.,Monash University | Chena X.D.,Xiamen University
Soft Matter | Year: 2011

Microparticles with homogeneous properties are crucial for pharmaceutical applications where the prior knowledge of exact drug loading and release behaviour is essential to achieve targeted therapeutic goals. Various methods such as membrane microemulsion or templating to assemble uniform particles often involve multiple steps, including post-processing for purification and recovery, with additional chemical reactivity is often required to form solid particles, rendering less flexibility in the procedure. Spray drying is a common method to produce pharmaceutical particles, although control over the particle properties poses a challenge. Here we used a specially designed dryer utilising a micro-fluidicaerosol- nozzle to atomize monodisperse droplets from a range of precursors, to generate uniform microparticles for controlled release applications. The versatility of the device enabled microparticles with easily tunable drug release kinetics to be assembled by adjusting the drying conditions or the composition of the precursors, including the use of dopants or different solvents. Significant adjustment of the release profiles could be realized by manipulating the microstructure of the microparticles. Due to the homogeneity of the particles, a direct correlation between the microstructural properties and release mechanisms could be obtained, the knowledge of which is crucial for the design of spray-dried polymeric-based pharmaceutical particles. © The Royal Society of Chemistry 2011. Source


Gu W.-M.,Xiamen University | Gu W.-M.,Harvard - Smithsonian Center for Astrophysics
Astrophysical Journal | Year: 2012

By taking into account the local energy balance per unit volume between the viscous heating and the advective cooling plus the radiative cooling, we investigate the vertical structure of radiation pressure-supported accretion disks in spherical coordinates. Our solutions show that the photosphere of the disk is close to the polar axis and therefore the disk seems to be extremely thick. However, the density profile implies that most of the accreted matter exists in a moderate range around the equatorial plane. We show that the well-known polytropic relation between the pressure and the density is unsuitable for describing the vertical structure of radiation pressure-supported disks. More importantly, we find that the energy advection is significant even for slightly sub-Eddington accretion disks. We argue that the non-negligible advection may help us understand why the standard thin disk model is likely to be inaccurate above 0.3 Eddington luminosity, which was found by some works on black hole spin measurement. Furthermore, the solutions satisfy the Solberg-Hoiland conditions, which indicate the disk to be convectively stable. In addition, we discuss the possible link between our disk model and ultraluminous X-ray sources. © 2012. The American Astronomical Society. All rights reserved.. Source


China's rapid development places growing pressure on its water resources, including its considerable transboundary waters. This paper analyses the current situation of China's transboundary water regimes through a legal analytical framework. The evaluation of treaty and state practice reveals that while China adheres to and follows some fundamental rules of international water law, gaps remain. New trends in China's state practice and in the field of international law offer interesting opportunities for addressing these shortcomings. © 2014 © 2014 International Water Resources Association. Source


International shipping carries around 80 per cent of global trade by volume and over 70 per cent by value. However, there is concern that the greenhouse gas (GHG) emissions from international shipping lead to adverse effects on climate, human health and marine ecosystems. Currently the international climate change regime under the United Nations Framework Convention on Climate Change (UNFCCC) process and the IMO through its Marine Environment Protection Committee are grappling with this issue, and GHG emissions from international shipping have been partially regulated by amendments to Annex VI to the International Convention for the Prevention of Pollution from Ships (MARPOL 73/78) in 2011 and 2014. These amendments aim to reduce GHG emissions from international shipping by means of technical and operational measures. However, research indicates that the adopted technical and operational measures alone would not achieve absolute emissions reduction due to projected growth of international seaborne trade. Currently it is still controversial whether it is time to consider market-based measures (MBMs) in furthering the reduction of shipping GHG emissions. This article examines whether it is necessary to adopt MBMs, proposes a preferred MBM, and suggests that a MBM be considered in or after 2016. © 2015 Elsevier Ltd. Source


Qu W.,Xiamen University
Ocean Development and International Law | Year: 2016

The real issue in the Chagos Marine Protection Area Arbitration should have been the dispute concerning the Lancaster House Undertakings, over which the Arbitral Tribunal had no jurisdiction. The UNCLOS has no express provision respecting the jurisdiction over mixed disputes— disputes involving territorial sovereignty and maritime boundary delimitation. Thus, a court or tribunal facing a mixed dispute should refrain from exercising its jurisdiction over the maritime issue if its resolution is premised on the resolution of the sovereignty issue involved. © 2016 Taylor & Francis Group, LLC. Source


Fechete I.,CNRS The Institute of Chemistry and Processes for Energy, Environment and Health | Wang Y.,Xiamen University | Vedrine J.C.,University Pierre and Marie Curie
Catalysis Today | Year: 2012

This review highlights key catalytic discoveries and the main industrial catalytic processes over the last 300 years that involved commodities, fine chemicals, petrochemicals, petroleum transformation for fuels and energy supply, emission control, and so forth. In the past, discoveries have often followed events such as wars or embargos, whereas the current driving forces of studies, researches and then discoveries aim at a better understanding of catalytic processes, at reducing the costs of raw materials and processes, at developing new catalytic materials and at addressing environmental issues. This review focuses on the history of many catalytic industrial processes, environmental issues, catalytic materials, especially their expected catalytic properties, on catalyst characterisation by physical methods and development of in situ conditions, i.e., characterisation under actual working conditions with reactants and products analyzed on-line. Emphasis is also placed on high selectivity in catalytic reactions and the major challenges for the future, such as environmental issues, energy supply, pollution control for vehicles and industrial plants, air/VOCs/water purification, hydrogen sources and carbon dioxide storage/up grading, transformation of biomass as a promising source of raw materials, and catalytic water splitting perspectives. This review is a survey of heterogeneous catalysis and is not comprehensive but leads to the conclusion that, although many catalysts and catalytic processes have already been discovered and developed over the past century, many opportunities nevertheless exist for new developments, new processes and new catalytic materials. It follows that substantial challenges exist for the younger generation of researchers and engineers, as emphasized at the end of the manuscript. © 2012 Elsevier B.V. All rights reserved. Source


Benenti G.,University of Insubria | Benenti G.,National Institute of Nuclear Physics, Italy | Casati G.,University of Insubria | Casati G.,National Institute of Nuclear Physics, Italy | Wang J.,Xiamen University
Physical Review Letters | Year: 2013

We show that generic systems with a single relevant conserved quantity reach the Carnot efficiency in the thermodynamic limit. Such a general result is illustrated by means of a diatomic chain of hard-point elastically colliding particles where the total momentum is the only relevant conserved quantity. © 2013 American Physical Society. Source


Chen Y.,Xiamen University | Chen C.,Fujian Medical University
Neurochemistry International | Year: 2011

Oxidative stress plays an important role in neurodegenerative diseases. Reactive oxygen species (ROS)-mediated stress in microglia in vivo could result in cellular injuries and preferentially induces neuronal injury. Corilagin, a novel member of the phenolic tannin family, has been shown to possess antioxidant properties. In this study, we investigated the effects of corilagin on tert-butyl hydroperoxide (TBHP)-induced injury in cultured N9 murine microglial cells and the underlying mechanisms by a methyltetrazolium assay and oxidative damage assay. We found that exposure of N9 cells to TBHP induced cytotoxicity as demonstrated by cell shrinkage, loss of cell viability, increased lactate dehydrogenase (LDH) leakage, and increased intracellular levels of ROS. By contrast, TBHP reduced both superoxide dismutase activity and total cell anti-oxidation capacity, but glutathione was not reduced. Moreover, TBHP treatment was associated with the loss of mitochondrial membrane potential, and it induced cell apoptosis through the mitochondrial-mediated pathway involving the down-regulation of Bcl-2 expression and up-regulation of the Bax/Bcl-2 ratio. Interestingly, pre-treatment with corilagin reversed these reactions. These data collectively indicated that corilagin could attenuate TBHP-induced oxidative stress injury in microglial cells, and its protective effects may be ascribed to its antioxidant and antiapoptotic properties. Our findings suggest that corilagin should be a potential candidate for the treatment of oxidative stress-induced neurodegenerative diseases. © 2011 Elsevier B.V. All rights reserved. Source


Du L.,Zhejiang University | He Y.,Xiamen University | Yan J.,University of International Business and Economics
Energy Economics | Year: 2013

This paper investigates the effects of electricity reforms on productivity and efficiency of China's generation plants, based on the third industrial census data and the first economic census data. Partial factor productivity (PFP) analysis indicates that the productivity improvements in labor and capital inputs associated with the reforms are approximately 26% and 45% respectively. The effect of the reforms on fuel expense is weakly significant, but there is evidence of significant productivity improvement in fuel usage. Further total factor productivity (TFP) analysis shows that the efficiency gain from the reforms is still significant when the substitution effect of labor and capital inputs are considered, though the magnitude is much lower than that of the PFP analysis. The effect of the reforms on technical efficiency becomes weakly significant when fuel expense is further included in TFP analysis, but a significant positive effect is expected if fuel input is measured in physical quantity. © 2013 Elsevier B.V. Source


Wang X.,Tsinghua University | Jin Y.,Tsinghua University | Zhao Y.,Tsinghua University | Zhao Y.,Xiamen University | And 2 more authors.
Organic Letters | Year: 2012

A highly efficient copper-catalyzed aerobic oxidative intramolecular C-H amination has been developed using substituted 2-(1H-imidazol-1-yl)-N- alkylbenzenamines as the starting materials, and the corresponding imidazobenzimidazole derivatives were obtained in excellent yields. This is an economical and practical method for the construction of N-heterocycles. © 2011 American Chemical Society. Source


In this paper, the inviscid and non-resistive limit is justified for the local-in-time solutions to the equations of nonhomogeneous incompressible magneto-hydrodynamics (MHD) in R3. We prove that as the viscosity and resistivity go to zero, the solution of the Cauchy problem for the nonhomogeneous incompressible MHD system converges to the solution of the ideal MHD system. The convergence rate is also obtained simultaneously. © 2011 Wuhan Institute of Physics and Mathematics. Source


Tao J.,Xiamen University
Computers and Operations Research | Year: 2014

The identical parallel machine scheduling problem with the objective of minimizing total weighted completion time is considered in the online setting where jobs arrive over time. An online algorithm is proposed and is proven to be (2.5-1/2m)-competitive based on the idea of instances reduction. Further computational experiments show the superiority over other algorithms in the average performance. © 2013 Elsevier Ltd. Source


He L.,Xiamen University
Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC | Year: 2013

Multilevel converters have been demonstrated to have many advantages such as low harmonic, low voltage stress, and high power capability. A multilevel DC-DC power conversion system with multiple bridge modular switched-capacitor converters (BMSCC) is proposed in this paper, with this conversion system, the output voltage can be changed almost continuously without any magnetic component, where the very high temperature operation is possible. Compared with other existing switched-capacitor converters, low semiconductor VA rating, low device requirement is available. Compared with other traditional step-up converters based on output impedance analysis method, the proposed converter brings about a higher efficiency advantage. Experimental results are provided to confirm the analysis and control concept. © 2013 IEEE. Source


Guo H.,University of Houston | Zhang Y.,Xiamen University | Lan Z.,University of Houston | Pennings S.C.,University of Houston
Global Change Biology | Year: 2013

Many species are expanding their distributions to higher latitudes due to global warming. Understanding the mechanisms underlying these distribution shifts is critical for better understanding the impacts of climate changes. The climate envelope approach is widely used to model and predict species distribution shifts with changing climates. Biotic interactions between species, however, may also influence species distributions, and a better understanding of biotic interactions could improve predictions based solely on climate envelope models. Along the northern Gulf of Mexico coast, USA, subtropical black mangrove (Avicennia germinans) at the northern limit of its distribution grows sympatrically with temperate salt marsh plants in Florida, Louisiana, and Texas. In recent decades, freeze-free winters have led to an expansion of black mangrove into salt marshes. We examined how biotic interactions between black mangrove and salt marsh vegetation along the Texas coast varied across (i) a latitudinal gradient (associated with a winter-temperature gradient); (ii) the elevational gradient within each marsh (which creates different marsh habitats); and (iii) different life history stages of black mangroves (seedlings vs. juvenile trees). Each of these variables affected the strength or nature of biotic interactions between black mangrove and salt marsh vegetation: (i) Salt marsh vegetation facilitated black mangrove seedlings at their high-latitude distribution limit, but inhibited black mangrove seedlings at lower latitudes; (ii) mangroves performed well at intermediate elevations, but grew and survived poorly in high- and low-marsh habitats; and (iii) the effect of salt marsh vegetation on black mangroves switched from negative to neutral as black mangroves grew from seedlings into juvenile trees. These results indicate that the expansion of black mangroves is mediated by complex biotic interactions. A better understanding of the impacts of climate change on ecological communities requires incorporating context-dependent biotic interactions into species range models. © 2013 John Wiley & Sons Ltd. Source


Zhao J.,Tsinghua University | Zhao Y.,Tsinghua University | Zhao Y.,Xiamen University | Fu H.,Tsinghua University
Organic Letters | Year: 2012

Phenol-derived electrophiles are favorable substrates because phenols are naturally abundant or can be readily prepared from other aromatic compounds. However, the cleavage of aromatic C-O bonds is a great challenge because of their high energy. K 2CO 3-catalyzed intramolecular cyclization of 1-(2-alkoxyphenyl)-3-akylpropane-1,3-dione and 3-(alkylimino)-1-(2-methoxyphenyl)-2-methylpropan-1-one derivatives via the selective cleavage of aromatic C-O bonds is reported. The corresponding chromone and 4-quinolone derivatives were obtained in reasonable yields. © 2012 American Chemical Society. Source


Wei M.,Xiamen University
Research Journal of Applied Sciences, Engineering and Technology | Year: 2013

The characteristics embodied in the experience economy are that production and consumption is a twin process and experience is the process "products". Wine tourism to a way of life we pursue and increasingly becoming a way of forming personal development and lifestyle. It is precisely these factors prompted the inevitable link between tourism and wine. In this context, world wine production capacity is relative to the spending power of the high-speed development, promoting wines Chamber of very great importance to the tourism promotion of the wine-producing areas and carrying flowers making strenuous efforts to tour around the world tour organized by exquisite wine show and tasting sessions. The promotion will let the wine-loving remember winery brand, therefore, tourists and media publicity personnel witnessed and taste product features publicize the beauty of food and wine; domestic wine market outlook was generally optimistic, but imports, domestic size winemakers a hot consumer incremental slow; buyout distribution, counterfeiting and other vicious competition impaired contradiction significant the wine market prospects and survival status quo, wine tourism is based on success on the international wine marketing experience, to seek a broader and more practical form of publicity and sales the channels proposed a new way of life. Combined with the development of the situation on the ground and research, this study describes the content and features of the wine tourism experience on the base of experience economy of wine tourism. Finally this study combines with a detailed analysis of Changyu wine tourism in Yantai and discussed issues related to the wine tourism experience. © Maxwell Scientific Organization, 2013. Source


Yuan F.,Chinese Academy of Sciences | Yuan F.,Xiamen University | Bu D.,Chinese Academy of Sciences | Wu M.,Chinese Academy of Sciences
Astrophysical Journal | Year: 2012

Hydrodynamical (HD) and magnetohydrodynamical (MHD) numerical simulations of hot accretion flows have indicated that the inflow accretion rate decreases inward. Two models have been proposed to explain this result. In the adiabatic inflow-outflow solution (ADIOS), this is because of the loss of gas in the outflow. In the alternative convection-dominated accretion flow model, it is thought that the flow is convectively unstable and gas is locked in convective eddies. We investigate the nature of the inward decrease of the accretion rate using HD and MHD simulations. We calculate various properties of the inflow and outflow such as temperature and rotational velocity. Systematic and significant differences are found. These results suggest that the inflow and outflow are not simply convective turbulence; instead, systematic inward and outward motion (i.e., real outflow) must exist. We have also analyzed the convective stability of MHD accretion flows and found that they are stable. These results favor the ADIOS scenario. We suggest that the mechanisms of producing outflow in HD and MHD flows are the buoyancy associated with the convection and the centrifugal force associated with the angular momentum transport mediated by the magnetic field, respectively. The latter is similar to the Blandford & Payne mechanism but no large-scale open magnetic field is required. We discuss some possible observational applications, including the Fermi bubble in the Galactic center and winds in active galactic nuclei and black hole X-ray binaries. © 2012. The American Astronomical Society. All rights reserved.. Source


Carson H.S.,University of California at San Diego | Lopez-Duarte P.C.,University of California at San Diego | Rasmussen L.,University of California at San Diego | Wang D.,Xiamen University | Levin L.A.,University of California at San Diego
Current Biology | Year: 2010

Populations of most marine organisms are connected by the dispersal of larval stages, with profound implications for marine conservation [1]. Because of the extreme effort needed to empirically measure larval exchange, multispecies conservation efforts must estimate connectivity by extrapolation using taxonomy, adult distribution, life history, behavior, or phenology. Using a 6-year record of connectivity realized through trace-elemental fingerprinting of larval shells, we document the seasonal and interannual variability of larval exchange for two congeneric mussel species with overlapping but distinct distribution, life history, and reproduction timing. We reveal consistent autumn poleward movement and spring equatorward movement for both species, coincident with near-shore surface currents. However, because the major reproductive seasons differ, the dominant source-sink dynamics of these two congeneric species are nearly opposite. Consideration of present and future reproductive timing as altered by climate change is crucial to marine connectivity and conservation, especially for the numerous coastal areas subject to seasonal current reversals. © 2010 Elsevier Ltd. All rights reserved. Source


Gao K.,Xiamen University | Campbell D.A.,Mount Allison University
Functional Plant Biology | Year: 2014

Diatoms dominate nearly half of current oceanic productivity, so their responses to ocean acidification are of general concern regarding future oceanic carbon sequestration. Community, mesocosm and laboratory studies show a range of diatom growth and photophysiological responses to increasing pCO2. Nearly 20 studies on effects of elevated pCO2 on diatoms have shown stimulations, no effects or inhibitions of growth rates. These differential responses could result from differences in experimental setups, cell densities, levels of light and temperature, but also from taxon-specific physiology. Generally, ocean acidification treatments of lowered pH with elevated CO 2 stimulate diatom growth under low to moderate levels of light, but lead to growth inhibition when combined with excess light. Additionally, diatom cell sizes and their co-varying metabolic rates can influence responses to increasing pCO2 and decreasing pH, although cell size effects are confounded with taxonomic specificities in cell structures and metabolism. Here we summarise known diatom growth and photophysiological responses to increasing pCO2 and decreasing pH, and discuss some reasons for the diverse responses observed across studies. © 2014 CSIRO. Source


Wu Y.,Xiamen University | Krishnan S.,Ryerson University
IEEE Transactions on Neural Systems and Rehabilitation Engineering | Year: 2010

To assess the gait variability in patients with Parkinson's disease (PD), we first used the nonparametric Parzen-window method to estimate the probability density functions (PDFs) of stride interval and its two subphases (i.e., swing interval and stance interval). The gait rhythm standard deviation (σ) parameters computed with the PDFs indicated that the gait variability is significantly increased in PD. Signal turns count (STC) was also derived from each outlier-processed gait rhythm time series to serve as a dominant feature, which could be used to characterize the gait variability in PD. Since it was observed that the statistical parameters of swing interval or stance interval were highly correlated with those of stride interval, this article only used the stride interval parameters, i.e., σr and STCr', to form the feature vector in the pattern classification experiments. The results evaluated with the leave-one-out cross-validation method demonstrated that the least squares support vector machine with polynomial kernels was able to provide a classification accurate rate of 90.32% and an area (Az) of 0.952 under the receiver operating characteristic curve, both of which were better than the results obtained with the linear discriminant analysis (accuracy: 67.74%, Az: 0.917). The features and the classifiers used in the present study could be useful for monitoring of the gait in PD. © 2010 IEEE. Source


Peng L.,South China University of Technology | Lin L.,Xiamen University | Li H.,South China University of Technology
Industrial Crops and Products | Year: 2012

A comprehensive experimental and kinetic investigation on the synthesis of methyl levulinate from glucose in methanol medium under mild conditions (≤473K) catalyzed by extremely low sulfuric acid (≤0.01molL-1) was performed in this study. Glucose was rapidly and almost quantitatively converted into methyl glucosides as a key and stable intermediate product, and a high methyl levulinate yield of ca. 50mol% can be achieved after the completion of reaction. Based on the detected compounds, a plausible reaction pathway for the acid-catalyzed conversion of glucose in methanol medium was proposed. The generation of methyl levulinate from glucose via methyl glucosides as a function of the process variables was modelled using a simplified first-order kinetic model, and a good fit between experimental data and the kinetic model was obtained. An advantage of this catalyst system is that negligible undesired dimethyl ether formed from the side reaction for the dehydration of methanol that was used as reaction medium, the equipment corrosion was slight, and less spent acid need to be addressed after the reaction. Overall, this catalytic strategy is efficient, economical and environmentally benign for the conversion of carbohydrates into high value-added chemicals and fuels. © 2012 Elsevier B.V. Source


Huang J.,Hunan University | Wu Y.,University of Florida | Chen Y.,Hunan University | Zhu Z.,University of Florida | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2011

Make it a double: Complementary probes with two pyrene labels were engineered for the amplification of a target DNA sequence. In the stem-closed conformation of the probes in the absence of the target, the two pyrene moieties were separated. The target propagated hybridization chain reactions to bring pyrene moieties on neighboring probes close together to form fluorescent pyrene excimers (see picture). © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Dong J.,Xiamen University | Ueda K.,University of Electro - Communications | Kaminskii A.A.,Russian Academy of Sciences
Laser Physics Letters | Year: 2010

The performance of laser-diode end-pumped Yb:LuAG microchip lasers has been investigated at ambient temperature without active cooling of the gain media. Efficient laser oscillation of Yb:LuAG crystals with different thickness and output couplings was achieved at 1030 and 1047 nm with slope efficiencies of 72 and 54%, correspondingly. The thermal population distribution at the terminated laser level of Yb:LuAG crystal plays an important role in the laser performance. The effects of the thickness of Yb:LuAG crystal and the transmission of output couplers on the laser oscillating wavelength and central wavelength shift were investigated by taking account into the reabsorption loss at lasing wavelength and intracavity laser intensity. (© 2010 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA). Source


Li Y.,Xiamen University
Advanced Materials Research | Year: 2012

In this paper, we discuss the possibility of using BIM into 3D indoor navigation in emergency response. We first analyze the functional requirements of 3D indoor emergency response, and then illustrate the workflow of transforming BIM into 3D, ontology-based, indoor navigation model, shortly as 3DOntoINM. Finally, we explain the algorithm and implication issues. Source


Yang L.,Fujian Medical University | Zhang J.,Fujian Medical University | Zheng K.,Xiamen University | Shen H.,Fujian Medical University | Chen X.,Fujian Medical University
Journals of Gerontology - Series A Biological Sciences and Medical Sciences | Year: 2014

In aging individuals, age-related cognitive decline is the most common cause of memory impairment. Among the remedies, ginsenoside Rg1, a major active component of ginseng, is often recommended for its antiaging effects. However, its role in improving cognitive decline during normal aging remains unknown and its molecular mechanism partially understood. This study employed a scheme of Rg1 supplementation for female C57BL/6J mice, which started at the age of 12 months and ended at 24 months, to investigate the effects of Rg1 supplementation on the cognitive performance. We found that Rg1 supplementation improved the performance of aged mice in behavior test and significantly upregulated the expression of synaptic plasticity-associated proteins in hippocampus, including synaptophysin, N-methyl-d-aspartate receptor subunit 1, postsynaptic density-95, and calcium/calmodulin-dependent protein kinase II alpha, via promoting mammalian target of rapamycin pathway activation. These data provide further support for Rg1 treatment of cognitive degeneration during aging. © The Author 2013. Source


In this paper, we investigate a class of delayed neural networks with impulsive and stochastic effects. By establishing an L- operator delay differential inequality with impulses and using the stochastic analysis technique, some sufficient conditions are derived to ensure the existence and global exponential stability of periodic solution for the addressed neural networks. Those conditions only including related parameters of neural networks can be easily checked by simple algebraic methods. Finally, two examples and their simulations are given to show the feasibility and effectiveness of our results. © 2009 Elsevier B.V. All rights reserved. Source


Wang P.,Xiamen University | Zhou Y.-N.,Shanghai JiaoTong University | Luo J.-S.,Catholic University of Leuven | Luo Z.-H.,Shanghai JiaoTong University
Polymer Chemistry | Year: 2014

In this study, a novel kind of organic-inorganic core-shell SiO 2-poly(p-vinylbenzyl) trimethylammonium tetrafluoroborate (SiO 2-P[VBTMA][BF4]) nanoparticle was well designed and successfully synthesized via surface-initiated atom transfer radical polymerization (SI-ATRP). Fourier transform infrared spectroscopy (FT-IR), 1H nuclear magnetic resonance (1H NMR), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS) and scanning electron microscopy (SEM) were used to confirm the formation of the core-shell nanoparticles and the surface modification. In order to overcome the challenge of the characterization of the number average molecular weight of poly(ionic liquid)s, "sacrificial initiator" method was used here employing a trimethylsilyl (TMS)-labeled initiator as the NMR marker for integration. In addition, good thermal stability of the new hybrid polyelectrolyte was proved by thermogravimetric analysis. The electrochemical impedance measurements revealed that the room temperature conductivity reached 10-4 S cm -1, which is much higher than that of the pure poly(ionic liquid)s and varies with the amount of the grafted polymer and the test temperature. The X-ray diffraction (XRD) tests further investigated the crystal structure of the nanocomposite and pure P[VBTMA][BF4]. The temperature dependence of ionic conductivity conforms to Arrhenius behavior for both of the nanocomposites and the pure polymer. The results indicated that the SI-ATRP approach provided a simple and versatile route to tune the ionic conductivity of the hybrid nanoparticles by changing the chain length of the grafted polymer, which can be potentially used in a variety of electrochemical devices. This journal is © 2014 The Royal Society of Chemistry. Source


Yuan X.,Xiamen University | Lu Z.,Northwestern Polytechnical University
Reliability Engineering and System Safety | Year: 2014

An efficient methodology is presented to perform the reliability-based optimization (RBO). It is based on an efficient weighted approach for constructing an approximation of the failure probability as an explicit function of the design variables which is referred to as the 'failure probability function (FPF)'. It expresses the FPF as a weighted sum of sample values obtained in the simulation-based reliability analysis. The required computational effort for decoupling in each iteration is just single reliability analysis. After the approximation of the FPF is established, the target RBO problem can be decoupled into a deterministic one. Meanwhile, the proposed weighted approach is combined with a decoupling approach and a sequential approximate optimization framework. Engineering examples are given to demonstrate the efficiency and accuracy of the presented methodology. © 2014 Elsevier Ltd. All rights reserved. Source


Wang W.,Northwest University, China | Zhao Y.,Xiamen University
Journal of Physical Chemistry C | Year: 2013

The rate constants and kinetic isotope effects of H2 dissociation and recombination on Ni(100) surface are calculated by using the quantum instanton method, together with path integral Monte Carlo and adaptive umbrella sampling techniques. The Ni(100) surface model containing 104 nickel atoms and the potential energy surface based on the embedded diatomics in molecules are used. For the H2 dissociation, the results on the rigid lattice are consistent with experimental data. Compared to the rigid lattice, the classical and quantum motions of the lattice further enhance the dissociation rates by 18 and 49% at 300 K. The calculated kinetic isotope effects show that the H2 always has the largest rate, while the D2 has the smallest one. For the H2 recombination, however, the effects of lattice motions on the rates are different from those for the dissociation, that is, compared to the rigid lattice, both the classical and quantum motions of the lattice lower the recombination rates. The possible mechanism is analyzed by the corresponding free energy profiles. © 2013 American Chemical Society. Source


Chen R.J.,Xiamen University
IEEE Transactions on Parallel and Distributed Systems | Year: 2011

In this paper, we use dynamic-bubblesort technology [4] to analyze general first-in-first-out K-queue homogenous fork/join queuing (HFJ) systems for any K ≥ 2. Jobs arrive with a mean rate λ and a general arrival distribution. Upon arrival, a job forks into K tasks. Task k,k= 1,2,..,K, is assigned to the kth queuing system, which is a first-in-first-out server with a general service distribution and an infinite capacity queue. A job leaves the HFJ system as soon as all its tasks complete their service. We mathematically prove an upper bound solution for the mean response time that we denote by T-K. The upper bound solution of general K-queue HFJ systems for any K ≥ 2 is very simple and practicalone only needs to simulate a small number of queues (e.g., 16 queues). The tightness is evaluated by comparing with the simulation of thousands of queues for three different HFJ cases. The maximum offset for our upper bounds over all the simulations is less than 5 percent. The corresponding source codes (reusable) are offered on our website for others to use. © 2011 IEEE. Source


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. Source


At present total usually charges the retailers the same per-unit cost for drop shipping as the regular replenishment orders. The drop-shipping option is only currently offered to large retail customers. The hospitality industry is contemplating offering drop shipping to all its retail customers at a premium over the per-unit cost of the regular replenishment orders. The problem the retailers facing is to develop an inventory policy which takes into account the drop-shipping option. In order to investigate the effect of inventory pattern on non-perishable inventory systems, we can consider using the quantity reorder-point inventory pattern in a continuous-review order. In this paper, hospitality industry will be researched in which condition that the retailers use an inventory pattern option when a shortage occurs during lead-time. And we can derive closed-form expressions for the optimal solutions under exponential and uniform demand distributions. © 2011 Published by Elsevier Ltd. Source


Liu C.-C.,Institute of Neuroscience | Kanekiyo T.,Mayo Medical School | Xu H.,Institute of Neuroscience | Bu G.,Institute of Neuroscience | Bu G.,Xiamen University
Nature Reviews Neurology | Year: 2013

Apolipoprotein E (Apo-E) is a major cholesterol carrier that supports lipid transport and injury repair in the brain. APOE polymorphic alleles are the main genetic determinants of Alzheimer disease (AD) risk: individuals carrying the ε4 allele are at increased risk of AD compared with those carrying the more common ε3 allele, whereas the ε2 allele decreases risk. Presence of the APOE ε4 allele is also associated with increased risk of cerebral amyloid angiopathy and age-related cognitive decline during normal ageing. Apo-E-lipoproteins bind to several cell-surface receptors to deliver lipids, and also to hydrophobic amyloid-β (Aβ) peptide, which is thought to initiate toxic events that lead to synaptic dysfunction and neurodegeneration in AD. Apo-E isoforms differentially regulate Aβ aggregation and clearance in the brain, and have distinct functions in regulating brain lipid transport, glucose metabolism, neuronal signalling, neuroinflammation, and mitochondrial function. In this Review, we describe current knowledge on Apo-E in the CNS, with a particular emphasis on the clinical and pathological features associated with carriers of different Apo-E isoforms. We also discuss Aβ-dependent and Aβ-independent mechanisms that link Apo-E4 status with AD risk, and consider how to design effective strategies for AD therapy by targeting Apo-E. © 2013 Macmillan Publishers Limited. All rights reserved. Source


Xiao S.-J.,Key Laboratory for Cell Biology and Tumor Cell Engineering | Zhang C.,Key Laboratory for Cell Biology and Tumor Cell Engineering | Zou Q.,Key Laboratory for Cell Biology and Tumor Cell Engineering | Ji Z.-L.,Key Laboratory for Cell Biology and Tumor Cell Engineering | Ji Z.-L.,Xiamen University
Bioinformatics | Year: 2010

Summary: The tissue-specific genes are a group of genes whose function and expression are preferred in one or several tissues/cell types. Identification of these genes helps better understanding of tissue-gene relationship, etiology and discovery of novel tissuespecific drug targets. In this study, a statistical method is introduced to detect tissue-specific genes from more than 123 125 gene expression profiles over 107 human tissues, 67 mouse tissues and 30 rat tissues. As a result, a novel subject-specialized repository, namely the tissue-specific genes database (TiSGeD), is developed to represent the analyzed results. Auxiliary information of tissue-specific genes was also collected from biomedical literatures. Availability: http://bioinf.xmu.edu.cn/databases/TiSGeD/index.html. Contact: appo@bioinf.xmu.edu.cn; zhiliang.ji@gmail.com. © The Author(s) 2010. Published by Oxford University Press. Source


Shi P.,Fujian Normal University | Huang Y.,Xiamen University | Hong J.,Fujian Medical University
Biomedical Optics Express | Year: 2014

A dendritic spine is a small membranous protrusion from a neuron's dendrite that typically receives input from a single synapse of an axon. Recent research shows that the morphological changes of dendritic spines have a close relationship with some specific diseases. The distribution of different dendritic spine phenotypes is a key indicator of such changes. Therefore, it is necessary to classify detected spines with different phenotypes online. Since the dendritic spines have complex three dimensional (3D) structures, current neuron morphological analysis approaches cannot classify the dendritic spines accurately with limited features. In this paper, we propose a novel semi-supervised learning approach in order to perform the online morphological classification of dendritic spines. Spines are detected by a new approach based on wavelet transform in the 3D space. A small training data set is chosen from the detected spines, which has the spines labeled by the neurobiologists. The remaining spines are then classified online by the semi-supervised learning (SSL) approach. Experimental results show that our method can quickly and accurately analyze neuron images with modest human intervention. ©2014 Optical Society of America. Source


This paper is concerned with longitudinal partially linear models (LPLM) with ultrahigh-dimensional covariates and predictors. As flexible extension of linear regression models by allowing nonparametric intercept function to capture the overall trend over time, the LPLM are expected to be highly potential statistical models for analyzing high-dimensional longitudinal data such as longitudinal genetic data and functional magnetic resonance image data. Feature screening and variable selection are indispensable for LPLM in the presence of ultrahigh-dimensional covariates such as genetic markers and all pixels in image data. This paper proposes a two-stage variable selection procedure that consists of a quick screening stage and a post-screening refining stage, for the ultrahigh dimensional longitudinal partially linear models. The proposed approach is based on the partial residual method for dealing with the nonparametric baseline function. We establish the sure screening property of the proposed screening procedure in the first stage. Simulation results demonstrate the validity of this two-stage method. We further demonstrate the proposed methodology by an empirical analysis of a real data set collected in a soybean plant longitudinal genetic study. © 2016 Elsevier B.V. Source


Li X.,Xiamen University | Bohner M.,Missouri University of Science and Technology
Mathematical and Computer Modelling | Year: 2010

In this paper, we deal with the exponential synchronization problem for a class of chaotic neural networks with mixed delays and impulsive effects via output coupling with delay feedback. The mixed delays in this paper include time-varying delays and unbounded distributed delays. By using a Lyapunov-Krasovskǐ functional, a drive-response concept and a linear matrix inequality (LMI) approach, several sufficient conditions are established that guarantee the exponential synchronization of the neural networks. Also, the estimation gains can be easily obtained. Finally, a numerical example and its simulation are given to show the effectiveness of the obtained results. © 2010 Elsevier Ltd. Source


Cai Q.,Xiamen University
Computational Statistics and Data Analysis | Year: 2016

In dealing with the multiplicity problem of large dataset, clusters or families of hypotheses are often the units of interest. A scoring method is motivated in adopting a rejection space for p-values that are classified into spatial or labeled groups. A score that measures the benefits/costs of making a true/false discovery is computed and rejection space that maximizes the number of rejections with positive score is adopted. Renewal and boundary-crossing theories are used to compute the exceedance probability of the score. Level of strong group type I error control is validated using Monte Carlo and importance sampling methods. It is shown that the scoring method maintains detection power and achieves robustness against model deviation. The scoring method is applied on a copy number variation tumor dataset and short intervals of the chromosome with biological relevance are identified. © 2016 Elsevier B.V. Source


Wang Y.-M.,Fuzhou University | Luo Y.,Xiamen University
Mathematical and Computer Modelling | Year: 2010

This paper proposes a correlation coefficient (CC) and standard deviation (SD) integrated approach for determining the weights of attributes in multiple attribute decision making (MADM) and a global sensitivity analysis to the weights determined. The CCSD integrated approach determines the weights of attributes by considering SD of each attribute and their CCs with the overall assessment of decision alternatives, where CCs are determined by removing each attribute from the overall assessment of decision alternatives. If the CC for an attribute turns out to be very high, then the removal of this attribute has little effect on decision making; otherwise, the attribute should be given an important weight. The global sensitivity analysis to the weights of attributes is proposed to ensure the stability of the best decision alternative or alternative ranking. A numerical example about the economic benefit assessment of the industrial economy of China is investigated to illustrate the potential applications of the CCSD method in determining the weights of attributes. Comparisons with existing weight generation methods are also discussed. © 2009 Elsevier Ltd. All rights reserved. Source


Ding X.,Duke University | Ding X.,Xiamen University | He L.,Duke University | Carin L.,Duke University
IEEE Transactions on Image Processing | Year: 2011

A hierarchical Bayesian model is considered for decomposing a matrix into low-rank and sparse components, assuming the observed matrix is a superposition of the two. The matrix is assumed noisy, with unknown and possibly non-stationary noise statistics. The Bayesian framework infers an approximate representation for the noise statistics while simultaneously inferring the low-rank and sparse-outlier contributions; the model is robust to a broad range of noise levels, without having to change model hyperparameter settings. In addition, the Bayesian framework allows exploitation of additional structure in the matrix. For example, in video applications each row (or column) corresponds to a video frame, and we introduce a Markov dependency between consecutive rows in the matrix (corresponding to consecutive frames in the video). The properties of this Markov process are also inferred based on the observed matrix, while simultaneously denoising and recovering the low-rank and sparse components. We compare the Bayesian model to a state-of-the-art optimization-based implementation of robust PCA; considering several examples, we demonstrate competitive performance of the proposed model. © 2006 IEEE. Source


Kwon T.-J.,University of Waterloo | Li J.,Xiamen University | Li J.,University of Waterloo | Wong A.,University of Waterloo
IEEE Transactions on Geoscience and Remote Sensing | Year: 2013

This paper presents a novel enhanced total variation optimization segmentation (ETVOS) approach consisting of two phases to segmentation of various sea-ice types. In the total variation optimization phase, the Rudin-Osher-Fatemi total variation model was modified and implemented iteratively to estimate the piecewise constant state from a nonpiecewise constant state (the original noisy imagery) by minimizing the total variation constraints. In the finite mixture model classification phase, based on the pixel distribution, an expectation maximization method was performed to estimate the final class likelihood using a Gaussian mixture model. Then, a maximum likelihood classification technique was utilized to estimate the final class of each pixel that appeared in the product of the total variation optimization phase. The proposed method was tested on a synthetic image and various subsets of RADARSAT-2 imagery, and the results were compared with other well-established approaches. With the advantage of a short processing time, the visual inspection and quantitative analysis of segmentation results confirm the superiority of the proposed ETVOS method over other existing methods. © 1980-2012 IEEE. Source


Liu Z.H.,Xiamen University | Zhu W.Q.,Zhejiang University
Probabilistic Engineering Mechanics | Year: 2012

Innovative procedures for the time-delay stochastic optimal control and stabilization of quasi-integrable Hamiltonian systems subject to Gaussian white noise excitations are proposed. First, the problem of time-delay stochastic optimal control of quasi-integrable Hamiltonian systems is formulated and converted into the problem of stochastic optimal control without time delay. Then the converted control problem is solved by applying the stochastic averaging method for quasi-integrable Hamiltonian systems and the stochastic dynamical programming principle. The time-delay feedback stabilization of quasi-integrable Hamiltonian systems is formulated as an ergodic control problem with an un-determined cost function which is determined later by minimizing the largest Lyapunov exponent of the controlled system. As an example, a two-degree-of-freedom quasi-integrable Hamiltonian system with time-delay feedback control forces is investigated in detail to illustrate the procedures and their effectiveness. © 2011 Elsevier Ltd. All rights reserved. Source


Shen Y.,Harbin Institute of Technology | Liu L.,Xiamen University | Dowell E.H.,Duke University
IET Control Theory and Applications | Year: 2013

An integrated design of the adaptive robust control and the fault identification for a linear system with actuator faults is proposed. When actuators suffer from unpredicted faults, the proposed control strategy can track the actuator fault parameters adaptively without any prior fault information, and guarantee the robustness of the faulty system. An unknown input observer is designed to decouple the disturbance and the actuator faults. Then an adaptive control law with projection is presented to track the fault parameters. A new definition of robust H∞-like performance is proposed to ensure that the system is robust for both exogenous disturbance and unpredicted faults. Then the adaptive robust control law is designed to guarantee the system satisfying the robust H∞-like performance. Finally, the effectiveness of this control strategy is illustrated through the faulttolerant longitudinal control of the simplified F-18 aircraft model. © The Institution of Engineering and Technology 2013. Source


Li B.,Xiamen University
Journal of Convergence Information Technology | Year: 2011

As to the problem of reducing and avoiding two kinds of risks of cruise line overbooking, this paper employs the real options approach to construct a cruise line overbooking risk decision model with multiple price classes, incremental cost and nonlinear goodwill loss. We give the steps to gain the best overbooking amount, find the real options connotative in the decision, explain the computing method of the real options included in the decision, and show that the overbooking decision can be regarded as different types of real options. Finally, a numerical example shows the effectiveness and meaning of the decision model. Source


Watthanasurorot A.,Uppsala University | Jiravanichpaisal P.,Uppsala University | Jiravanichpaisal P.,National Science and Technology Development Agency | Liu H.,Uppsala University | And 3 more authors.
PLoS Pathogens | Year: 2011

The Down syndrome cell adhesion molecule, also known as Dscam, is a member of the immunoglobulin super family. Dscam plays an essential function in neuronal wiring and appears to be involved in innate immune reactions in insects. The deduced amino acid sequence of Dscam in the crustacean Pacifastacus leniusculus (PlDscam), encodes 9(Ig)-4(FNIII)-(Ig)-2(FNIII)-TM and it has variable regions in the N-terminal half of Ig2 and Ig3 and the complete Ig7 and in the transmembrane domain. The cytoplasmic tail can generate multiple isoforms. PlDscam can generate more than 22,000 different unique isoforms. Bacteria and LPS injection enhanced the expression of PlDscam, but no response in expression occurred after a white spot syndrome virus (WSSV) infection or injection with peptidoglycans. Furthermore, PlDscam silencing did not have any effect on the replication of the WSSV. Bacterial specific isoforms of PlDscam were shown to have a specific binding property to each tested bacteria, E. coli or S. aureus. The bacteria specific isoforms of PlDscam were shown to be associated with bacterial clearance and phagocytosis in crayfish. © 2011 Watthanasurorot et al. Source


Xu L.,Jingdezhen Ceramic Institute | Sun D.,Xiamen University
Applied Physics Letters | Year: 2013

A pole-type nozzle has an inserted pole that jams a contraction flow into capillary in electrohydrodynamic deposition. The jammed solution improves Taylor cone formation by shortening the hysteresis time so that pole-type nozzle is suitable for high-resolution electrohydrodynamic printing. Experimental results demonstrate a governed frequency-dividing relationship with an integral ratio of applied voltage frequency to droplet deposition frequency. It is observed that low integral frequency ratio is in favor of low voltage amplitude and duty cycle, and high voltage frequency, since polymer solution jets in a small fluidic volume per droplet under low electric force and short pulse duration. © 2013 American Institute of Physics. Source


Ota A.,University of California at Los Angeles | Zhang J.,University of California at Los Angeles | Ping P.,University of California at Los Angeles | Han J.,Xiamen University | Wang Y.,University of California at Los Angeles
Circulation Research | Year: 2010

Rationale: p38 is an important stress activated protein kinase involved in gene regulation, proliferation, differentiation, and cell death regulation in heart. p38 kinase activity can be induced through canonical pathway via upstream kinases or by noncanonical autophosphorylation. The intracellular p38 kinase activity is tightly regulated and maintained at low level under basal condition. The underlying regulatory mechanism for canonical p38 kinase activation is well-studied, but the regulation of noncanonical p38 autophosphorylation remains poorly understood. Objective: We investigated the molecular basis for the regulation of noncanonical p38 autophosphorylation and its potential functional impact in cardiomyocytes. Methods and Results: Using both proteomic and biochemical tools, we established that heat shock protein (Hsp)90-Cdc37 chaperones are part of the p38α signaling complex in mammalian cells both in vitro and in vivo. The Hsp90-Cdc37 chaperone complex interacts with p38 via direct binding between p38 and Cdc37. Cdc37 expression is both sufficient and necessary to suppress noncanonical p38 activation via autophosphorylation at either basal state or under TAB1 (TAK1 binding protein-1) induction. In contrast, Cdc37 expression has no impact on p38 activation by canonical upstream kinase MKK3 or oxidative stress. Furthermore, Hsp90 inhibition results in p38 activation via autophosphorylation, and p38 activity contribute to apoptotic cell death induced by Hsp90 inhibition. Conclusion: Our study has revealed a so far uncharacterized function of Hsp90-Cdc37 as an endogenous regulator of noncanonical p38 activity. © 2010 American Heart Association, Inc. Source


Nie L.,U.S. National Institutes of Health | Nie L.,Xiamen University | Chen X.,U.S. National Institutes of Health
Chemical Society Reviews | Year: 2014

Photoacoustic tomography (PAT) can offer structural, functional and molecular contrasts at scalable observation level. By ultrasonically overcoming the strong optical scattering, this imaging technology can reach centimeters penetration depth while retaining high spatial resolution in biological tissue. Recent extensive research has been focused on developing new contrast agents to improve the imaging sensitivity, specificity and efficiency. These emerging materials have substantially accelerated PAT applications in signal sensing, functional imaging, biomarker labeling and therapy monitoring etc. Here, the potentials of different optical probes as PAT contrast agents were elucidated. We first describe the instrumental embodiments and the measured functional parameters, then focus on emerging contrast agent-based PAT applications, and finally discuss the challenges and prospects. This journal is © the Partner Organisations 2014. Source


Hong Y.-G.,CAS South China Sea Institute of Oceanography | Yin B.,CAS South China Sea Institute of Oceanography | Zheng T.-L.,Xiamen University
Applied Microbiology and Biotechnology | Year: 2011

The community structure and diversity of anaerobic ammonium oxidation (anammox) bacteria in the surface sediments of equatorial Pacific were investigated by phylogenic analysis of 16S rRNA and hydrazine oxidoreductase (hzo) genes and PCoA (principal coordinates analysis) statistical analysis. Results indicated that 16S rRNA and hzo sequences in the P2 (off the center of western Pacific warm pool) and P3 (in the eastern equatorial Pacific) sites all belong to the Candidatus "Scalindua", the dominate anammox bacteria in the low-temperature marine environment proved by previous studies. However, in the P1 site (in center of warm pool of western Pacific), large part of 16S rRNA gene sequences formed a separated cluster. Meanwhile, hzo gene sequences from P1 sediment also grouped into a single cluster. PCoA analysis demonstrated that the anammox community structure in the P1 has significant geographical distributional difference from that of P2, P3, and other marine environments based on 16S rRNA and hzo genes. The abundances of anammox bacteria in surface sediments of equatorial Pacific were quantified by q-PCR analysis of hzo genes, which ranged from 3.98 × 10 3 to 1.17 × 10 4 copies g -1 dry sediments. These results suggested that a special anammox bacteria phylotypes exist in the surface sediment of the western Pacific warm pool, which adapted to the specific habitat and maybe involved in the nitrogen loss process from the fixed inventory in the habitat. © 2011 Springer-Verlag. Source


Ramasamy P.,Annamalai University | Ramasamy P.,Xiamen University | Shanmugam A.,Annamalai University
International Journal of Biological Macromolecules | Year: 2015

The present findings were aimed to develop an effective form of collagen-chitosan film to investigate the wound healing property in Wistar rats. Primarily, the acid-soluble collagen (ASC) isolated, structurally and physicochemically characterized. FT-IR and 1H NMR spectra were confirmed the collagen peptide crosslinks. The molecular weight of ASC subunits was about 86kDa and 79kDa, the proline and hydroxyproline content was 13.15% and 7.55%, respectively. In addition, collagen-chitosan films were successfully prepared in a controlled environment and characterized by FT-IR and DSC. In wound healing, the experimental animal model showed the increased wound size reduction in the CChF treated rats (96.25%) when compared to control rats (33.75%) followed by CF treated rats (65%) and ChF (55%). The histological results well supported these findings. It can be concluded that a better and faster epithelization was observed in the CChF group compared to the other groups. © 2014 Elsevier B.V. Source


Yu J.,Xiamen University | Liu D.,Nanyang Technological University | Tao D.,Intelligent Systems Technology, Inc. | Seah H.S.,Nanyang Technological University
IEEE Transactions on Image Processing | Year: 2011

Correspondence construction of objects in key frames is the precondition for inbetweening and coloring in 2-D computer-assisted animation production. Since each frame of an animation consists of multiple layers, objects are complex in terms of shape and structure. Therefore, existing shape-matching algorithms specifically designed for simple structures such as a single closed contour cannot perform well on objects constructed by multiple contours with an open shape. This paper introduces a semisupervised patch alignment framework for complex object correspondence construction. In particular, the new framework constructs local patches for each point on an object and aligns these patches in a new feature space, in which correspondences between objects can be detected by the subsequent clustering. For local patch construction, pairwise constraints, which indicate the corresponding points (must link) or unfitting points (cannot link), are introduced by users to improve the performance of correspondence construction. This kind of input is convenient for animation software users via user-friendly interfaces. A dozen of experimental results on our cartoon data set that is built on industrial production suggest the effectiveness of the proposed framework for constructing correspondences of complex objects. As an extension of our framework, additional shape retrieval experiments on MPEG-7 data set show that its performance is comparable with that of a prominent algorithm published in T-PAMI 2009. © 2011 IEEE. Source


Lin S.,Xiamen University | Fu L.,Chinese University of Hong Kong
IEEE Transactions on Wireless Communications | Year: 2013

In this paper, we investigate the throughput performance of physical-layer network coding (PNC) under the IEEE 802.11 distributed coordination function (DCF). We consider the wireless network that two client groups communicate with each other across one relay node, and focus on the unsaturated network case. The difficulty in modeling the relay systems under the IEEE 802.11 DCF is that the minimum contention window sizes of the client nodes and the relay node may be different, which makes the traditional throughput analysis methods for the non-relay wireless networks inapplicable. Fortunately, we find that the relay system can be decomposed into four parts and respectively modeled. Analytical results show that the throughput gain of PNC scheme is heavily affected by the probability that a transmitted network-coding (NC) packet contains the information of two packets. The implication is that the throughput benefit of PNC is more significant for bidirectional isochronous traffic with rate requirements.We further derive an approximate closed-form solution of the optimal transmission probability of client nodes that maximizes the PNC network throughput. We validate our analytical model through extensive simulations and discuss the relationship between the PNC network throughput and other system parameters, such as the minimum contention window sizes of both the client nodes and the relay node. © 2013 IEEE. Source


An X.Y.,Chinese Academy of Sciences | Wu Q.Q.,Xiamen University
Scientometrics | Year: 2011

In this paper, co-word analysis is used to analyze the evolvement in stem cell field. Articles in the stem cell journals are downloaded from PubMed for analysis. Terms selection is one of the most important steps in co-word analysis, so the useless and the general subject headings are removed firstly, and then the major subject headings and minor subject headings are weighted respectively. Then, improved information entropy is exploited to select the subject headings with the experts consulting. Hierarchical cluster analysis is used to cluster the subject headings and the strategic diagram is formed to analyze the evolutionary trends in the stem cell field. © 2011 Akadémiai Kiadó, Budapest, Hungary. Source


Wu Z.,Fujian Engineering College | Li Z.,Fujian Engineering College | Yang L.,Fujian Engineering College | Han J.,Xiamen University | Han S.,Fujian Engineering College
Chemical Communications | Year: 2012

Selective detection of hydrogen sulfide was achieved with 7-o-2′-(azidomethyl)benzoyl-4-methylcoumarin via analyte mediated reductive removal of the 2′-(azidomethyl)benzoyl moiety and concurrent generation of fluorescent 7-hydroxy-4-methylcoumarin. This journal is © The Royal Society of Chemistry 2012. Source


Tanaka K.-I.,Saitama Institute of Technology | Shou M.,Saitama Institute of Technology | Yuan Y.,Xiamen University
Journal of Physical Chemistry C | Year: 2010

Preferential oxidation (PROX) reaction of CO in H2 proceeded rapidly on Pt supported on carbon nanotube (CNT) at room temperature, whereas the oxidation of CO was very slow in the absence of H2. On the other hand, no low temperature PROX reaction proceeded on Pt supported on the CNT purified Ni-MgO (CNT-p). Similarly, Pt supported on carbon nanofiber (Pt/CNF) was extremely active for the PROX reaction of CO at room temperature, but the activity of Pt supported on purified CNF (CNF-p) was very low. Pt particles are on the wall of CNT and CNF, whereas Ni-MgO and Fe are at the end of CNT and CNF. When Ni-MgO or Fe-Al2O3 was doped to inactive Pt/CNT-p, Pt/CNF-p, Pt/graphite, and Pt/amorphous-C (a-C), the activity for the oxidation of CO in H2 was markedly improved but no effect on the oxidation of CO in the absence of H2. The kinetic feature of the oxidation of CO on Pt/CNT in the presence of H2 or H2O was very similar to that on the FeOx/Pt/TiO2, where the oxidation of CO in the presence of H2/D2 had an isotope effect. A dual functional mechanism catalyzing CO(a) + OH- → HCOO- and HCOO + OH → CO2 + H2O was proposed, and the contribution of OH- anion was deduced by an experiment neutralizing OH- anion on the Pt/CNT with H+ diffused from the anode of polymer electrolyte hydrogen fuel cell (PEFC). The proposed mechanism is entirely different from the H-assisted dissociation of O2 proposed by Alayoglu et al. on a Pt-shell/Ru-core catalyst. © 2010 American Chemical Society. Source


Xiao L.,Xiamen University | Mandayam N.B.,Rutgers University | Vincent Poor H.,Princeton University
IEEE Transactions on Smart Grid | Year: 2015

The energy exchange between microgrids (MGs) that are capable of generating power from renewable energy sources in smart grids is investigated. As MGs are autonomous and have control over their energy exchange, prospect theory is a useful tool to provide a user-centric view on MG power trading. More specifically, in this paper, the energy exchange among MGs that are also connected to a power plant as a backup energy supply is formulated as a prospect theory-based static game and Nash equilibria are provided under various scenarios. The impact of user objective weight is evaluated during the outcome evaluation on the performance of the game. Simulation results show that user subjectivity tends to exaggerate selling and buying probabilities when battery levels are high (and low), and thus decreases the overall utility and increases the amount of the energy bought at either low battery levels or low MG selling prices. Conditions on the pricing system to ensure that the energy exchange system is not impacted by the subjective view of MGs are also provided. © 2010-2012 IEEE. Source


Hu T.,Xiamen University | Li C.,Vanderbilt University
Molecular Cancer | Year: 2010

Wnt and EGFR signaling play key roles in embryonic development and cell proliferation. It is well documented that dysregulation of these two pathways often leads to tumorigenesis with poor prognosis. However, the possible crosstalk between the two pathways in cancer development is largely unknown. Although some reports show that EGFR might antagonize Wnt signaling during development in Drosophila, an increasing body of evidence indicates that Wnt and EGFR signaling crosstalk and transactivate one another in development and cancer. This review summarizes recent studies on the crosstalk between Wnt and EGFR signaling in cancers and points out several possible convergence points. Wnt ligands can activate EGFR signaling through their 7-transmembrane domain receptor Frizzled while EGFR can activate β-catenin via receptor tyrosine kinase-PI3K/Akt pathway; EGFR has been shown to form a complex with β-catenin and increase the invasion and metastasis of cancer cells. NKD2, a Wnt antagonist by interacting with Dishevelled, also escorts TGFα-containing exocytic vesicles to the basolateral membrane of polarized epithelial cells. Down-regulation of NKD2 causes Wnt activation and TGFα misdelivery, suggesting its functions in cell homeostasis and prevention of tumorigenesis.© 2010 Hu and Li; licensee BioMed Central Ltd. Source


Zhou Z.-Y.,University of California at Santa Cruz | Zhou Z.-Y.,Xiamen University | Kang X.,University of California at Santa Cruz | Song Y.,University of California at Santa Cruz | Chen S.,University of California at Santa Cruz
Chemical Communications | Year: 2012

Chlorophenyl-stabilized platinum nanoparticles (1.85 nm) exhibited electrocatalytic activity for oxygen reduction up to 3 times higher than that of commercial Pt/C catalysts. Similar enhancement was observed with naked Pt/C functionalized by the same chlorophenyl fragments, suggesting the important role of organic capping ligands in the manipulation of nanoparticle electrocatalytic performance. © 2012 The Royal Society of Chemistry. Source


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

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


Cao M.-K.,Xiamen University
Journal of Software | Year: 2011

Traditional research in automated negotiation is focused on negotiation protocol and strategy, but they cannot satisfy all the requirements for realizing a practical automated negotiation system. This paper focuses on agent's independent decision-making process; formally defines automated negotiation's abstract concept model, which is made up of three sub-concept models, they are negotiation environment, negotiation process and negotiating agent; designs negotiating agent's architecture based on the concept model, which can support both goal-directed reasoning and reactive response; proposes an algorithm for running the decision making model. Finally, for illustration, the model is applied to an exemplified negotiation process for aircraft purchasing. © 2011 ACADEMY PUBLISHER. Source


He J.,Northwestern University | He J.,Xian University of Science and Technology | Girard S.N.,Northwestern University | Zheng J.-C.,Xiamen University | And 3 more authors.
Advanced Materials | Year: 2012

The incorporation of PbSnS2 in PbTe results in a tremendous reduction of the lattice thermal conductivity to 0.8 W/mK at room temperature, a reduction of almost 60% over bulk PbTe. Transmission electron microscopy reveals very high density displacement layers, misfit dislocations, and phase boundaries. Our thermal transport calculations based on modified Debye-Callaway model, well in agreement with the experimental measurements, reveal that the layer structured PbSnS2 plays an important role in reducing the lattice thermal conductivity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Ma S.,University of Wisconsin - Madison | Ma S.,Yale University | Dai Y.,Xiamen University
Briefings in Bioinformatics | Year: 2011

In analysis of bioinformatics data, a unique challenge arises from the high dimensionality of measurements. Without loss of generality, we use genomic study with gene expression measurements as a representative example but note that analysis techniques discussed in this article are also applicable to other types of bioinformatics studies. Principal component analysis (PCA) is a classic dimension reduction approach. It constructs linear combinations of gene expressions, called principal components (PCs). The PCs are orthogonal to each other, can effectively explain variation of gene expressions, and may have a much lower dimensionality. PCA is computationally simple and can be realized using many existing software packages. This article consists of the following parts. First, we review the standard PCA technique and their applications in bioinformatics data analysis. Second, we describe recent 'non-standard' applications of PCA, including accommodating interactions among genes, pathways and network modules and conducting PCAwith estimating equations as opposed to gene expressions. Third, we introduce several recently proposed PCA-based techniques, including the supervised PCA, sparse PCA and functional PCA. The supervised PCA and sparse PCA have been shown to have better empirical performance than the standard PCA. The functional PCA can analyze time-course gene expression data. Last, we raise the awareness of several critical but unsolved problems related to PCA. The goal of this article is to make bioinformatics researchers aware of the PCA technique and more importantly its most recent development, so that this simple yet effective dimension reduction technique can be better employed in bioinformatics data analysis. Source


Zhang Z.,Lanzhou Jiaotong University | Li X.,Xiamen University
IEEE Transactions on Reliability | Year: 2010

This note studies coherent systems with independent, s-identically distributed (i.i.d.) components. Aging properties and stochastic orders are established for the general residual life, and the general inactivity time. © 2010 IEEE. Source


Liu M.,Xiamen University | Liu M.,University of California at Berkeley | Hsu J.,University of California at Berkeley | Chan C.,University of California at Berkeley | And 2 more authors.
Molecular Cell | Year: 2012

Super . elongation . complexes (SECs) contain two different transcription elongation factors, P-TEFb and ELL1/2, linked by the scaffolding protein AFF4 or AFF1. They stimulate the expression of both normal and disease-related genes, especially those of HIV or those involved in leukemogenesis. Among all SEC subunits, ELL2 is stoichiometrically limiting and uniquely regulated at the level of protein stability. Here we identify the RING domain protein Siah1, but not the homologous Siah2, as the E3 ubiquitin ligase for ELL2 polyubiquitination and proteasomal degradation. Siah1 cannot access and ubiquitinate ELL2 bound to AFF4, although, at high concentrations, it also degrades AFF4/1 to destroy SECs. Prostratin and HMBA, two well-studied activators of HIV transcription and latency, enhance ELL2 accumulation and SECs formation largely through decreasing Siah1 expression and ELL2 polyubiquitination. Given its importance in formation of SECs, the Siah1 ubiquitination pathway provides a fresh avenue for developing strategies to control disease-related transcription. © 2012 Elsevier Inc. Source


Huang C.-S.,National Sun Yat - sen University | Arbogast T.,University of Texas at Austin | Qiu J.,Xiamen University
Journal of Computational Physics | Year: 2012

We develop a locally conservative Eulerian-Lagrangian finite volume scheme with the weighted essentially non-oscillatory property (EL-WENO) in one-space dimension. This method has the advantages of both WENO and Eulerian-Lagrangian schemes. It is formally high-order accurate in space (we present the fifth order version) and essentially non-oscillatory. Moreover, it is free of a CFL time step stability restriction and has small time truncation error. The scheme requires a new integral-based WENO reconstruction to handle trace-back integration. A Strang splitting algorithm is presented for higher-dimensional problems, using both the new integral-based and pointwise-based WENO reconstructions. We show formally that it maintains the fifth order accuracy. It is also locally mass conservative. Numerical results are provided to illustrate the performance of the scheme and verify its formal accuracy. © 2012 Elsevier Inc. Source


Zhou R.,Mount Sinai School of Medicine | Lin J.,Xiamen University | Wu D.,Mount Sinai School of Medicine
Biochimica et Biophysica Acta - General Subjects | Year: 2014

Background The mechanism(s) by which alcohol causes cell injury are still not clear but a major mechanism appears to be the role of lipid peroxidation and oxidative stress in alcohol toxicity. CYP2E1-generated ROS contributes to the ethanol-induced oxidant stress and inhibition of CYP2E1 activity decreases ethanol-induced fatty liver. The transcription factor Nrf2 regulates the expression of many cytoprotective enzymes which results in cellular protection against a variety of toxins. Method The current study was designed to evaluate the ability of sulforaphane, an activator of Nrf2, to blunt CYP2E1-dependent, ethanol-induced steatosis in vivo and in vitro. Results The sulforaphane treatment activated Nrf2, increased levels of the Nrf2 target heme oxygenase-1 and subsequently lowered oxidant stress as shown by the decline in lipid peroxidation and 3-nitrotyrosine protein adducts and an increase in GSH levels after the acute ethanol treatment. It decreased ethanol-elevated liver levels of triglycerides and cholesterol and Oil Red O staining. Similar results were found in vitro as addition of sulforaphane to HepG2 E47 cells, which express CYP2E1, elevated Nrf2 levels and decreased the accumulation of lipid in cells cultured with ethanol. Sulforaphane treatment had no effect on levels of or activity of CYP2E1. Conclusions Sulforaphane proved to be an effective in vivo inhibitor of acute ethanol-induced fatty liver in mice. General significance The possible amelioration of liver injury which occurs under these conditions by chemical activators of Nrf2 is of clinical relevance and worthy of further study. © 2013 Elsevier B.V. Source


Li X.,Chinese Academy of Sciences | Lin B.,Minjiang University | Lin B.,Xiamen University
Renewable and Sustainable Energy Reviews | Year: 2013

Climate change is now widely recognized as the major environmental problem. In order to reduce CO2 emissions so as to cope with climate change, a wide range of effective policies, and an enforced international cooperation are required. A better understanding of the dynamic changes of CO2 emissions will strengthen international cooperation and provide necessary information for policy making. This paper investigates the global convergence in per capita CO2 emissions over the period 1971-2008. The results manifest an absolute convergence within subsamples grouped by income level, while provide little evidence of absolute convergence in the full sample containing 110 countries. Furthermore, this paper takes the GDP per capita into consideration within the conditional convergence framework. Interestingly, the result shows that, within different income groups, the relationships between GDP per capita and per capita CO2 emission growth are different. Specially, per capita CO2 emissions of high-income countries keep at the "steady state" as income rises. This result is contrary to Environmental Kuznets Curve, which indicates that the CO2 emissions will decline when income rises beyond a certain level. © 2013 Elsevier Ltd. Source


Weng Z.-H.,Xiamen University
International Journal of Geometric Methods in Modern Physics | Year: 2016

The paper aims to extend major equations in the electromagnetic and gravitational theories from the flat space into the complex octonion curved space. Maxwell applied simultaneously the quaternion analysis and vector terminology to describe the electromagnetic theory. It inspires subsequent scholars to study the electromagnetic and gravitational theories with the complex quaternions/octonions. Furthermore Einstein was the first to depict the gravitational theory by means of tensor analysis and curved four-space-time. Nowadays some scholars investigate the electromagnetic and gravitational properties making use of the complex quaternion/octonion curved space. From the orthogonality of two complex quaternions, it is possible to define the covariant derivative of the complex quaternion curved space, describing the gravitational properties in the complex quaternion curved space. Further it is possible to define the covariant derivative of the complex octonion curved space by means of the orthogonality of two complex octonions, depicting simultaneously the electromagnetic and gravitational properties in the complex octonion curved space. The result reveals that the connection coefficient and curvature of the complex octonion curved space will exert an influence on the field strength and field source of the electromagnetic and gravitational fields, impacting the linear momentum, angular momentum, torque, energy, and force and so forth. © 2016 World Scientific Publishing Company. Source


Burgio G.F.,National Institute of Nuclear Physics, Italy | Schulze H.-J.,National Institute of Nuclear Physics, Italy | Li A.,Xiamen University
Physical Review C - Nuclear Physics | Year: 2011

We perform Brueckner-Hartree-Fock calculations of hypernuclear matter at finite temperature and provide convenient analytical parametrizations of the results. We then study the properties of (proto)neutron stars containing hyperons. We find important effects of trapping and finite temperature on the structure of hyperonic stars. © 2011 American Physical Society. Source


Gao J.,Xiamen University | Gao J.,Stanford University | Chen K.,Stanford University | Luong R.,Stanford University | And 5 more authors.
Nano Letters | Year: 2012

The use of quantum dots (QDs) in biomedical research has grown tremendously, yet successful examples of clinical applications are absent due to many clinical concerns. Here, we report on a new type of stable and biocompatible dendron-coated InP/ZnS core/shell QD as a clinically translatable nanoprobe for molecular imaging applications. The QDs (QD710-Dendron) were demonstrated to hold several significant features: near-infrared (NIR) emission, high stability in biological media, suitable size with possible renal clearance, and ability of extravasation. More importantly, a pilot mouse toxicity study confirmed that QD710-Dendron lacks significant toxicity at the doses tested. The acute tumor uptake of QD710-Dendron resulted in good contrast from the surrounding nontumorous tissues, indicating the possibility of passive targeting of the QDs. The highly specific targeting of QD710-Dendron-RGD 2 to integrin α vβ 3-positive tumor cells resulted in high tumor uptake and long retention of the nanoprobe at tumor sites. In summary, QD710-Dendron and RGD-modified nanoparticles demonstrate small size, high stability, biocompatibility, favorable in vivo pharmacokinetics, and successful tumor imaging properties. These features satisfy the requirements for clinical translation and should promote efforts to further investigate the possibility of using QD710-Dendron-based nanoprobes in the clinical setting in the near future. © 2011 American Chemical Society. Source


Song G.-L.,Xiamen University | Song G.-L.,University of Queensland | Shi Z.,University of Queensland
Corrosion Science | Year: 2014

The corrosion of anodized Mg alloys is investigated by means of immersion, salt spray, polarization curve, AC electrochemical impedance spectroscopy (EIS), SEM and optical microscopy analyses. Based on the blocking, retarding and passivating effects of an anodized coating on corrosion of Mg alloys, a corrosion model is proposed to illustrate the corrosion reaction at the coating/substrate interface in coating through-pores. It is found that EIS can sensitively respond to the occurrence of corrosion in anodized Mg alloys and reflect the protection performance of anodized coatings, which may be used as an in situ method of monitoring corrosion for anodized Mg alloys. © 2014 Elsevier Ltd. Source


Li Y.-L.,Xiamen University
Solid State Communications | Year: 2013

We perform a detailed density functional theory study on the low-index CdTe/CdSe(100), (110) and (111) interfaces. The relaxed interlayer distance, the adhesion energy and the stability of the CdTe/CdSe interface are analyzed. The density of states and the band structure of the three models are also investigated and compared with those of the bulk CdTe and CdSe. Our calculations reveal that the (110) interface shows semiconducting properties with a direct band gap about 0.5 eV. However, (100) and (111) interfaces are metallic. These properties are different from those of the bulk CdTe and CdSe. © 2012 Elsevier Ltd. Source


Min W.,Xiamen University
Journal of Convergence Information Technology | Year: 2011

Food, housing, transportation, travel, shopping and entertainment constitute the six elements of tourism, but if we can effectively reduce the cost of "transportation", we can directly save the whole cost of travel. According to requirements of the research and development for tourism and transportation monitoring system, combined with ASP. NET technology and a variety of integrated development approach, a set of tourist traffic and transport statistical information systems have been designed in this paper. ASP.NET applications have not changed a great deal through ASP's development. Granted, the actual tourist traffic and transportation have definitely changed dramatically, but the application concept itself has not; an ASP.NET application is still defined as the developer-created files and directories that can be requested, invoked, and processed through ASP.NET within its local directory structures. By analyzing and designing the requirements of the system's function, the key technical issues which are to solve during the design process, such as user authentication, themes and skin, three-layer structure model have been pointed out. Thus, the applications of ASP. NET technology can effectively reduce travel costs, but also can it ensure the tourism enterprises in trade secrets. Source


Hong W.,Institute of Molecular and Cell Biology | Hong W.,National University of Singapore | Hong W.,Xiamen University
Science Signaling | Year: 2013

The Hippo pathway regulates cell proliferation and apoptosis during development, tissue regeneration, and carcinogenesis. Nuclear translocation of the transcription factors Yes-associated protein (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) and their subsequent interaction with TEA domain (TEAD) transcriptional factors program pro-proliferative and antiapoptotic transcription. Scaffold proteins angiomotin (Amot) and angiomotin-related AmotL1 and AmotL2 were recently identifi ed as negative regulators of YAP and TAZ by preventing their nuclear translocation. In this issue of Science Signaling, Yi et al. show that Amot may also promote nuclear translocation of YAP and act as a transcriptional cofactor of the YAP-TEAD complex to facilitate proliferation of biliary epithelial cells and cancer development of the liver either in response to tissue injury or in the absence of the tumor suppressor Merlin. These seemingly controversial results highlight that our understanding of Amot proteins in the Hippo pathway is so far limited. Copyright © 2008 by the American Association for the Advancement of Science. Source


Xia X.,Washington University in St. Louis | Zeng J.,Washington University in St. Louis | McDearmon B.,Washington University in St. Louis | Zheng Y.,Washington University in St. Louis | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2011

Shaped and dimpled: Silver nanocrystals enclosed by concave surfaces and thus high-index facets have been prepared by simply controlling the growth habit of Ag cubic seeds. Four types of concave nanocrystals, including octahedron, cube, octapod, and trisoctahedron, were obtained (see picture). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


Weng Z.-H.,Xiamen University
AIP Advances | Year: 2014

The paper aims to adopt the complex octonion to formulate the angular momentum, torque, and force etc in the electromagnetic and gravitational fields. Applying the octonionic representation enables one single definition of angular momentum (or torque, force) to combine some physics contents, which were considered to be independent of each other in the past. J. C. Maxwell used simultaneously two methods, the vector terminology and quaternion analysis, to depict the electromagnetic theory. It motivates the paper to introduce the quaternion space into the field theory, describing the physical feature of electromagnetic and gravitational fields. The spaces of electromagnetic field and of gravitational field can be chosen as the quaternion spaces, while the coordinate component of quaternion space is able to be the complex number. The quaternion space of electromagnetic field is independent of that of gravitational field. These two quaternion spaces may compose one octonion space. Contrarily, one octonion space can be separated into two subspaces, the quaternion space and S-quaternion space. In the quaternion space, it is able to infer the field potential, field strength, field source, angular momentum, torque, and force etc in the gravitational field. In the S-quaternion space, it is capable of deducing the field potential, field strength, field source, current continuity equation, and electric (or magnetic) dipolar moment etc in the electromagnetic field. The results reveal that the quaternion space is appropriate to describe the gravitational features, including the torque, force, and mass continuity equation etc. The S-quaternion space is proper to depict the electromagnetic features, including the dipolar moment and current continuity equation etc. In case the field strength is weak enough, the force and the continuity equation etc can be respectively reduced to that in the classical field theory. © 2014 Author(s). Source


Zhang L.,Leiden University | Zhou F.,Leiden University | Drabsch Y.,Leiden University | Gao R.,Xiamen University | And 7 more authors.
Nature Cell Biology | Year: 2012

The stability and membrane localization of the transforming growth factor-β (TGF-β) type I receptor (TβRI) determines the levels of TGF-β signalling. TβRI is targeted for ubiquitylation-mediated degradation by the SMAD7-SMURF2 complex. Here we performed a genome-wide gain-of-function screen and identified ubiquitin-specific protease (USP) 4 as a strong inducer of TGF-β signalling. USP4 was found to directly interact with TβRI and act as a deubiquitylating enzyme, thereby controlling TβRI levels at the plasma membrane. Depletion of USP4 mitigates TGF-β-induced epithelial to mesenchymal transition and metastasis. Importantly, AKT (also known as protein kinase B), which has been associated with poor prognosis in breast cancer, directly associates with and phosphorylates USP4. AKT-mediated phosphorylation relocates nuclear USP4 to the cytoplasm and membrane and is required for maintaining its protein stability. Moreover, AKT-induced breast cancer cell migration was inhibited by USP4 depletion and TβRI kinase inhibition. Our results uncover USP4 as an important determinant for crosstalk between TGF-β and AKT signalling pathways. © 2012 Macmillan Publishers Limited. All rights reserved. Source


He X.,Stanford University | He X.,Hunan University | Gao J.,Stanford University | Gao J.,Xiamen University | And 2 more authors.
Trends in Molecular Medicine | Year: 2010

Near-infrared fluorescence (NIRF) imaging promises to improve cancer imaging and management; advances in nanomaterials allow scientists to combine new nanoparticles with NIRF imaging techniques, thereby fulfilling this promise. Here, we present a synopsis of current developments in NIRF nanoprobes, their use in imaging small living subjects, their pharmacokinetics and toxicity, and finally their integration into multimodal imaging strategies. We also discuss challenges impeding the clinical translation of NIRF nanoprobes for molecular imaging of cancer. Whereas utilization of most NIRF nanoprobes remains at a proof-of-principle stage, optimizing the impact of nanomedicine in cancer patient diagnosis and management will probably be realized through persistent interdisciplinary amalgamation of diverse research fields. © 2010 Elsevier Ltd. Source


Yuan Q.,Tsinghua University | Yuan Q.,Guizhou University | Zhou Z.,Xiamen University | Zhuang J.,Tsinghua University | Wang X.,Tsinghua University
Chemical Communications | Year: 2010

Monodisperse, highly-selective sub-10 nm Pd-Pt random alloy nanocubes have been successfully synthesized in aqueous solution, and the electrocatalytic activity of these Pd-Pt alloys towards formic acid oxidation was investigated and compared with the activity of Pd sub-10 nm nanocubes, and the commercial Pd and Pt black. © The Royal Society of Chemistry 2010. Source


Zhang H.,Ningbo University | Chen L.,Sanming University | Zhang J.,Ningbo University | Chen J.,Xiamen University
Energy | Year: 2014

The model of a packed bed anode DCFC (direct carbon fuel cell) with molten carbonate as an electrolyte and graphite as a fuel is established to globally evaluate its performance. Thermodynamic-electrochemical analyses on the performance of the DCFC are implemented, in which the activation overpotential, ohmic overpotential, and concentration overpotential are taken as the main sources of voltage losses. The analytical expressions for the cell voltage, power output, efficiency, and entropy production rate are derived, from which the general performance characteristics are discussed in detail. At the anode, the ohmic overpotential in each slab resulting from the carbon phase is found to be about three orders of magnitude larger than that resulting from the electrolyte phase. The radius of the real contact area between two neighboring graphite particles decreases at an accelerating rate as one goes up in the bed, and the corresponding constriction resistance will increase at an accelerating rate. The decrease in the operating current density and anode dimension and the increase in the operating temperature will lessen the overall ohmic overpotential. The effects of the operating current density, operating temperature and anode dimension on the performance are discussed, and the optimum criteria for some important performance parameters are determined. © 2014 Elsevier Ltd. Source


Zhao X.,Xiamen University
Current Opinion in Microbiology | Year: 2014

Bacteria are killed by a variety of lethal stressors, some of which promote a cascade of reactive oxygen species (ROS). Perturbations expected to alter ROS accumulation affect the lethal action of diverse antibacterials, leading to the hypothesis that killing by these agents can involve ROS-mediated self-destruction. Recent challenges to the hypothesis are considered, particularly with respect to complexities in assays that distinguish primary damage from the cellular response to that damage. Also considered are bifunctional factors that are protective at low stress levels but destructive at high levels. These considerations, plus new data, support an involvement of ROS in the lethal action of some antimicrobials and raise important questions concerning consumption of antioxidant dietary supplements during antimicrobial chemotherapy. © 2014 Elsevier Ltd. Source


Wang T.,South China University of Technology | Lin B.,Minjiang University | Lin B.,Xiamen University
Energy Policy | Year: 2014

China's natural gas consumption is growing rapidly and it has being driven by economic growth, industrialization and urbanization. In addition, the country's low-carbon development strategy, government-controlled gas price, and some other factors also contribute to the surging gas consumption. This paper studies China's natural gas consumption in residential, industrial and commercial sectors. We adopt the cointegration test and error correction model to study the relationships of explanatory factors and gas consumption of different sectors and climate factor is included into the analysis. In order to find the direction of natural gas pricing reform and establish the benchmark gas price, this paper also estimates the size of gas price subsidy by using price-gap approach. Our findings are as follows: In the long term, China's residential sector is more sensitive to price than the other two. Urbanization is an important factor promoting industrial and commercial gas consumption. Prices of other energies have an influence on natural gas consumption significantly due to the substitutability between energies. The slow-moving and unsatisfying pricing reforms on refined oil and natural gas lead to positive price elasticity of natural gas in the commercial sector, which implies that a further energy price reform is still stringent for China. © 2013 Elsevier Ltd. Source


Zhang S.-J.,Huaqiao University | Zheng Y.-X.,Huaqiao University | Yuan L.-S.,Huaqiao University | Zhao L.-H.,Xiamen University
Journal of Power Sources | Year: 2014

Nanoporous Cu (NPC) prepared by dealloying CuZn alloy is used as an economic substrate for the fabrication of Ni-B alloy (Ni-B/NPC) by ultrasonic-assisted electroless technique. The results of scanning electron microscopy (SEM) and X-ray diffraction (XRD) demonstrate the NPC has a bicontinuous network structure and the Ni-B/NPC alloy is amorphous structure with highly dispersed nanoparticles. Electrochemical performances are measured by cyclic voltammetry (CV), chronoamperometry (CA) and linear sweep voltammetry (LSV). The results suggest that the Ni-B/NPC electrode prepared for 5 min shows the highest electrochemical activity and its redox species coverage and proton diffusion coefficient are remarkably improved compared with the bulk Ni. Ethanol oxidation at the Ni-B/NPC electrode suggests the onset oxidation potential has a negative shift of 52 mV and the oxidation peak current increases by 19.4 times, and apparent activation energy decreases 4.75-30.60 kJ mol-1 at the same potential, in comparison with the bulk Ni. Additionally, the reaction rate constant for ethanol oxidation at the Ni-B/NPC electrode is improved by about one order of magnitude relative to the reported value. Finally, the Ni-B/NPC electrode has a stable redox behavior after complete activation and superior catalytic stability for ethanol oxidation. © 2013 Elsevier B.V. All rights reserved. Source


Lu L.,Nanyang Technological University | Hong W.,Drive.SG | Hong W.,Xiamen University
Seminars in Cell and Developmental Biology | Year: 2014

The retrograde trafficking from endosomes to the trans-Golgi network (TGN) is one of the major endocytic pathways to divert proteins and lipids away from lysosomal degradation. Retrograde transported cargos enter the TGN via two itineraries from either the early endosome/recycling endosome or the late endosome and involve various machinery components such as retromer, sorting nexins, clathrin, small GTPases, tethering factors and SNAREs. Recently, the pathway has been recognized for its role in signal transduction, physiology and pathogenesis of human diseases. © 2014 Elsevier Ltd. Source


Cheng L.,Anhui Science and Technology University | Ren C.,Xiamen University | Zhang X.,Anhui Science and Technology University | Yang J.,Anhui University of Science and Technology
Nanoscale | Year: 2013

Based on the recently proposed super valence bond model, in which superatoms can compose superatomic molecules by sharing valence pairs and nuclei for shell closure, the 23c-14e bi-icosahedral Au23(+9) core of Au38(SR)24 is proved to be a superatomic molecule. Molecular orbital analysis reveals that the Au23(+9) core is an exact analogue of the F2 molecule in electronic configuration. Chemical bonding analysis by the adaptive natural density partitioning method confirms the superatomic molecule bonding framework of Au38(SR) 24 in a straightforward manner. © 2013 The Royal Society of Chemistry. Source


Yang W.,Xiamen University | Guo L.,University of Wisconsin - Milwaukee
Geophysical Research Letters | Year: 2014

There exists increasing evidence supporting the important role of black carbon in global carbon cycles. Particulate black carbon (PBC) is allochthonous and has distinct reactivities compared to the bulk particulate organic carbon (tot-POC) in marine environments. However, the abundance, geochemical behavior of PBC and its importance in oceanic carbon budget remain poorly understood. Here we report the abundance, distribution, and stable isotopic signatures of BC derived from the chemo-thermal oxidation (CTO-375) method (BCCTO) in the Gulf of Mexico. Our results show that BCCTO abundance decreased from shelf to basin, and more than a half of riverine BCCTO could be removed over the shelf. Moreover, BCCTO is much more refractory compared to the tot-POC and has δ13C values lower than those of BC-excluded POC. These results highlight the significance of PBC in marine carbon cycles and potentially suggest the need for a new end-member term in quantifying POC sources in the ocean. Key Points BC could result in an overestimate of autochthonous POC in the ocean13C abundance of soot BC is up to 12‰ lower than BC-excluded POC>50% of the riverine soot BC is removed on the shelf ©2014. American Geophysical Union. All Rights Reserved. Source


Chen X.,Jimei University | Chen X.,Kyoto University | Cai Z.,Xiamen University | Oyama M.,Kyoto University
Journal of Materials Chemistry A | Year: 2014

A facile and green method is described for the fabrication of PtPd alloy nanoparticles on graphene nanosheets (PtPdNPs/GNs). The keys of the synthesis strategy were to employ a low-cost and green solvent, ethanol, as the reductant, and a two-dimensional carbon material, GNs, as the supporting material. The morphology, structure and composition of the as-prepared PtPdNPs/GNs were characterized by transmission electron microscopy (TEM), high resolution TEM, energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. It was found that by changing the preparation procedures and varying the molar ratio of the starting precursors, NPs with different shapes such as spherical NPs (Pt1Pd1NPs), nanoflowers (Pd@PtNFs) and nanodentrites (Pt3Pd1NPs) could be produced on GNs. Based on these observations, a plausible growth mechanism of PtPdNPs/GNs was discussed. In addition, the electrocatalytic properties of PtPdNPs/GNs for direct ethanol oxidation in alkaline media were systematically investigated. Due to the synergetic effects of Pt and Pd, and the enhanced electron transfer properties enhanced of GNs, PtPdNPs/GNs exhibited higher electrocatalytic ability and better tolerance to reaction intermediate poisoning in the electrooxidation of ethanol compared with Pt nanoflowers supported on GNs (PtNFs/GNs), PdNPs/GNs and PtPdNPs supported on carbon black (PtPdNPs/C). The presented method is a general, facile and green approach for the synthesis of GN-supported bimetallic PtM electrocatalysts, which is significant for the development of high performance electrocatalysts. © 2013 The Royal Society of Chemistry. Source


Chen G.C.,City University of Hong Kong | Tam N.F.Y.,City University of Hong Kong | Ye Y.,Xiamen University
Science of the Total Environment | Year: 2010

The atmospheric fluxes of N2O, CH4 and CO2 from the soil in four mangrove swamps in Shenzhen and Hong Kong, South China were investigated in the summer of 2008. The fluxes ranged from 0.14 to 23.83μmolm-2h-1, 11.9 to 5168.6μmolm-2h-1 and 0.69 to 20.56mmolm-2h-1 for N2O, CH4 and CO2, respectively. Futian mangrove swamp in Shenzhen had the highest greenhouse gas fluxes, followed by Mai Po mangrove in Hong Kong. Sha Kong Tsuen and Yung Shue O mangroves in Hong Kong had similar, low fluxes. The differences in both N2O and CH4 fluxes among different tidal positions, the landward, seaward and bare mudflat, in each swamp were insignificant. The N2O and CO2 fluxes were positively correlated with the soil organic carbon, total nitrogen, total phosphate, total iron and NH4+-N contents, as well as the soil porosity. However, only soil NH4+-N concentration had significant effects on CH4 fluxes. © 2010 Elsevier B.V. Source


Lei T.,CAS Beijing National Laboratory for Molecular | Dou J.-H.,CAS Beijing National Laboratory for Molecular | Cao X.-Y.,Xiamen University | Wang J.-Y.,CAS Beijing National Laboratory for Molecular | Pei J.,CAS Beijing National Laboratory for Molecular
Journal of the American Chemical Society | Year: 2013

Poly(p-phenylene vinylene) derivatives (PPVs) are one of the most widely investigated p-type polymers in organic electronics. PPVs generally exhibit electron mobilities lower than 10-4 cm2 V-1 s-1, thus hindering their applications in high-performance polymer field-effect transistors and organic photovoltaics. Herein, we design and synthesize a novel electron-deficient PPV derivative, benzodifurandione-based PPV (BDPPV). This new PPV derivative displays high electron mobilities up to 1.1 cm2 V-1 s-1 under ambient conditions (4 orders of magnitude higher than those of other PPVs), because it overcomes common defects in PPVs, such as conformational disorder, weak interchain interaction, and a high LUMO level. BDPPV represents the first polymer that can transport electrons over 1 cm2 V-1 s-1 under ambient conditions. © 2013 American Chemical Society. Source


Drying is a complex process which involves simultaneous heat and mass transfer. Complicated structure and heterogeneity of food and biological materials add to the complexity of drying. Drying models are important for improving dryer design and for evaluating dryer performance. The lumped reaction engineering approach (L-REA) has been shown to be an accurate and robust alternative for cost-effective simulations of challenging drying systems. However, more insightful physics has to be shown spatially. In this study, the REA is coupled with the standard mechanistic drying models to yield the spatial-REA (S-REA) as nonequilibrium multiphase mass-transfer model. The S-REA consists of a system of equations of conservation with the REA representing the local evaporation and wetting rate. Results of the modeling using the S-REA match well with the experimental data reported previously. This is the first comprehensive REA approach to model the profiles of water vapor concentration during drying of food and biological materials. This study indicates that the S-REA can be an accurate nonequilibrium multiphase mass-transfer model with appropriate account of the local evaporation rate. The overall REA concept is expected to contribute substantially for better and cost-effective representation of transport phenomena of drying process.copy; 2012 American Institute of Chemical Engineers (AIChE). Source


Hong W.,Xiamen University | Hong W.,Institute of Molecular and Cell Biology | Lev S.,Weizmann Institute of Science
Trends in Cell Biology | Year: 2014

The fusion of transport vesicles with their target membranes is fundamental for intracellular membrane trafficking and diverse physiological processes and is driven by the assembly of functional soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes. Prior to fusion, transport vesicles are physically linked to their target membranes by various tethering factors. Recent studies suggest that tethering factors also positively regulate the assembly of functional SNARE complexes, thereby coupling tethering with fusion events. This coupling is mediated, at least in part, by direct physical interactions between tethering factors, SNAREs, and Sec1/Munc18 (SM) proteins. In this review we summarize recent progress in understanding the roles of tethering factors in the assembly of specific and functional SNARE complexes driving membrane-fusion events. © 2013 Elsevier Ltd. Source


Volker T.,University of Marburg | Dempwolff F.,LOEWE Zentrum fur Synthetische Mikrobiologie | Graumann P.L.,LOEWE Zentrum fur Synthetische Mikrobiologie | Meggers E.,University of Marburg | Meggers E.,Xiamen University
Angewandte Chemie - International Edition | Year: 2014

The catalysis of bioorthogonal transformations inside living organisms is a formidable challenge - yet bears great potential for future applications in chemical biology and medicinal chemistry. We herein disclose highly active organometallic ruthenium complexes for bioorthogonal catalysis under biologically relevant conditions and inside living cells. The catalysts uncage allyl carbamate protected amines with unprecedented high turnover numbers of up to 270 cycles in the presence of water, air, and millimolar concentrations of thiols. By live-cell imaging of HeLa cells and with the aid of a caged fluorescent probe we could reveal a rapid development of intense fluorescence within the cellular cytoplasm and therefore support the proposed bioorthogonality of the catalysts. In addition, to illustrate the manifold applications of bioorthogonal catalysis, we developed a method for catalytic in-cell activation of a caged anticancer drug, which efficiently induced apoptosis in HeLa cells. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA. Source


Mazumder V.,Brown University | Chi M.,Oak Ridge National Laboratory | Mankin M.N.,Brown University | Liu Y.,Brown University | And 4 more authors.
Nano Letters | Year: 2012

Monodisperse CoPd nanoparticles (NPs) were synthesized and studied for catalytic formic acid (HCOOH) oxidation (FAO). The NPs were prepared by coreduction of Co(acac) 2 (acac = acetylacetonate) and PdBr 2 at 260 °C in oleylamine and trioctylphosphine, and their sizes (5-12 nm) and compositions (Co 10Pd 90 to Co 60Pd 40) were controlled by heating ramp rate, metal salt concentration, or metal molar ratios. The 8 nm CoPd NPs were activated for HCOOH oxidation by a simple ethanol wash. In 0.1 M HClO 4 and 2 M HCOOH solution, their catalytic activities followed the trend of Co 50Pd 50 > Co 60Pd 40 > Co 10Pd 90 > Pd. The Co 50Pd 50 NPs had an oxidation peak at 0.4 V with a peak current density of 774 A/g Pd. As a comparison, commercial Pd catalysts showed an oxidation peak at 0.75 V with peak current density of only 254 A/g Pd. The synthesis procedure could also be extended to prepare CuPd NPs when Co(acac) 2 was replaced by Cu(ac) 2 (ac = acetate) in an otherwise identical condition. The CuPd NPs were less active catalysts than CoPd or even Pd for FAO in HClO 4 solution. The synthesis provides a general approach to Pd-based bimetallic NPs and will enable further investigation of Pd-based alloy NPs for electro-oxidation and other catalytic reactions. © 2012 American Chemical Society. Source


Smith I.F.,University of California at Irvine | Shuai J.,Xiamen University | Parker I.,University of California at Irvine
Biophysical Journal | Year: 2011

A new mechanism of cell-cell communication was recently proposed after the discovery of tunneling nanotubes (TNTs) between cells. TNTs are membrane protrusions with lengths of tens of microns and diameters of a few hundred nanometers that permit the exchange of membrane and cytoplasmic constituents between neighboring cells. TNTs have been reported to mediate intercellular Ca 2+ signaling; however, our simulations indicate that passive diffusion of Ca 2+ ions alone would be inadequate for efficient transmission between cells. Instead, we observed spontaneous and inositol trisphosphate (IP 3)-evoked Ca 2+ signals within TNTs between cultured mammalian cells, which sometimes remained localized and in other instances propagated as saltatory waves to evoke Ca 2+ signals in a connected cell. Consistent with this, immunostaining showed the presence of both endoplasmic reticulum and IP 3 receptors along the TNT. We propose that IP 3 receptors may actively propagate intercellular Ca 2+ signals along TNTs via Ca 2+-induced Ca 2+ release, acting as amplification sites to overcome the limitations of passive diffusion in a chemical analog of electrical transmission of action potentials. © 2011 by the Biophysical Society. Source


Ye B.,Xiamen University
Physiological Research | Year: 2010

Intracellular free Ca2+ is one of important biological signals regulating a number of cell functions. It has been discussed widely and extensively in several cell types during the past two decades. Attention has been paid to the Ca2+ transportation in mesenchymal stem cells in recent years as mesenchymal stem cells have gained considerable interest due to their potential for cell replacement therapy and tissue engineering. In this paper, roles of intracellular Ca2+ oscillations and its transporters in mesenchymal stem cells have been reviewed. © 2010 Institute of Physiology v.v.i., Academy of Sciences of the Czech Republic. Source


Tartakoff A.M.,Case Western Reserve University | Tao T.,Xiamen University
International Journal of Biochemistry and Cell Biology | Year: 2010

Membrane barriers preserve the integrity of organelles of eukaryotic cells, yet the genesis and ongoing functions of the same organelles requires that their limiting membranes allow import and export of selected macromolecules. Multiple distinct mechanisms are used for this purpose, only some of which have been traced to prokaryotes. Some can accomodate both monomeric and also large heterooligomeric cargos. The best characterized of these is nucleocytoplasmic transport. This synthesis compares the unidirectional and bidirectional mechanisms of macromolecular transport of the endoplasmic reticulum, mitochondria, peroxisomes and the nucleus, calls attention to the powerful experimental approaches which have been used for their elucidation, discusses their regulation and evolutionary origins, and highlights relatively unexplored areas. © 2009 Elsevier Ltd. All rights reserved. Source


Electronic motion is not mechanical movement in Euclidean space with Newtonian time, where linear algebra is applied to physical quantities. Electronic motion obeys Faraday's law in atomic spacetime where dynamic calculus of spherical quantities is the rule. Here, the author puts forward a novel four-dimensional space theory, defining 2s2p electronic orbitals in a neon shell using geometry, trigonometry, and dynamic calculus consistently in the context of harmonic oscillation. The 2p electronic orbitals in a neon atom are not equally distributed in the X, Y, and Z directions, but are anisotropic in Cartesian coordinates. Specifically, 2px orbitals are two onedimensional poles; 2py orbitals are two flat sectors; and 2pz orbitals are two hemispheres. Anisotropic 2s2p orbitals are the origin of a chiral carbon center when fixed by four different substituents. The theory effectively explains the structures and reaction mechanisms of methane, ethene, ethyne, and other organic compounds without appealing to orbital hybridization. It is a perfect complement to quantum mechanics for describing the multielectron system. Copyright © 2015 Physics Essays Publication. Source


Weng Z.-H.,Xiamen University
International Journal of Modern Physics A | Year: 2015

The paper aims to consider the electromagnetic adjoint-field in the complex octonion space as the dark matter field, describing some properties of the dark matter, especially the origin, particle category, existence region, force and so forth. Since Maxwell applied the algebra of quaternions to depict the electromagnetic theory, some scholars adopt the complex quaternion and octonion to study the physics property of electromagnetic and gravitational fields. In the paper, by means of the octonion operator, it is found that the gravitational field accompanies with one adjoint-field, whose property is partly similar to that of electromagnetic field. The electromagnetic field accompanies with another adjoint-field, whose feature is partly similar to that of gravitational field. As a result, the electromagnetic adjoint-field can be chosen as one candidate of the dark matter field. According to the electromagnetic adjoint-field, it is able to predict a few properties of the dark matter, for instance, the particle category, interaction intensity, interaction distance, existence region and so forth. The study reveals that the dark matter particle and the gravitational resource will be influenced by the gravitational strength and force. The dark matter field is capable of making a contribution to physics quantities of gravitational field, including the angular momentum, torque, energy, force and so on. Further, there may be comparatively more chances to discover the dark matter in some regions with the ultrastrong field strength, surrounding the neutral star, white dwarf, galactic nucleus, black hole, astrophysical jet and so on. © 2015 World Scientific Publishing Company. Source


Wu W.,Xiamen University | Zhou S.,CUNY - College of Staten Island
Macromolecular Bioscience | Year: 2013

With diabetes mellitus becoming an important public health concern, insulin-delivery systems are attracting increasing interest from both scientific and technological researchers. This feature article covers the present state-of-the-art glucose-responsive insulin-delivery system (denoted as GRIDS), based on responsive polymer materials, a promising system for self-regulated insulin delivery. Three types of GRIDS are discussed, based on different fundamental mechanisms of glucose-recognition, with: a) glucose enzyme, b) glucose binding protein, and c) synthetic boronic acid as the glucose-sensitive component. At the end, a personal perspective on the major issues yet to be worked out in future research is provided. Glucose-responsive materials are promising for construction of smart insulin delivery systems, which can self-regulate the insulin release if a certain level of glucose level is exceeded, similar to normal pancreatic activity. Herein, glucose-responsive insulin-delivery systems based on polymer materials are discussed with: a) glucose enzyme, b) glucose binding protein, and c) synthetic boronic acid as glucose sensitive components. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source


The Yarlung Zangbo/Brahmaputra, shared by China, India, Bhutan and Bangladesh, lacks a comprehensive legal framework. Following an overview of the basin, the paper analyses state and treaty practice through a legal lens, comparing the riparian state positions, based on their approaches to sovereignty. Finding fragmented transboundary water cooperation across the basin, two possible approaches that might help are explored. Taking inspiration from the hydropower projects on parts of the watercourse, and from existing multilateral environmental agreements, it is queried whether future cooperation might be fostered through legal arrangements for joint exploitation, or through joint protection under multilateral environmental agreements. © 2015,International Water Resources Association. Source


Forbes V.L.,Xiamen University
Water International | Year: 2015

National interest, enhancing the nation’s wealth and welfare, and fostering development are factors cited for the awareness of the need of accurate and detailed topographic maps. These aspects are clearly spelt out in China’s Law No. 75 of 2002. An overview of the status of mapping in China in the context of overall management of its trans-boundary rivers is presented. Public access to these graphics is restricted in this regional context; they are available only to bona fide users. The importance of maps in the context of the trans-boundary water discourse is discussed. © 2014, © 2014 International Water Resources Association. Source


Gao K.,Xiamen University | Helbling E.W.,CONICET | Hader D.-P.,Neue Str. 9 | Hutchins D.A.,University of Southern California
Marine Ecology Progress Series | Year: 2012

Anthropogenic CO2 is accumulating in the atmosphere and trapping reflected infrared radiation, resulting in warming of both terrestrial and ocean ecosystems. At the same time, the dissolution of CO2 into seawater is increasing surface ocean acidity, a process known as ocean acidification. Effects of ocean acidification on marine primary producers have been documented to be stimulative, inhibitive, or neutral. Elevated CO 2 and reduced pH levels can interact with solar radiation, which fluctuates over different time scales from limiting to saturating or even stressful levels, to bring about synergistic, antagonistic, or balanced effects on marine primary producers at different depths or under changing weather conditions. However, shoaling of the upper mixed layer (enhanced stratification) due to ocean warming and freshening (rain, ice melting) can lead to additional photosynthetically active radiation (PAR) and ultraviolet (UV) exposure, which can have both benefits and costs to photosynthetic organisms. Elevated CO 2 concentrations under low or moderate levels of PAR have been shown to enhance photosynthesis or growth of both phytoplankton and macroalgae; excessive levels of PAR, however, can lead to additional inhibition of photosynthesis or growth under elevated CO2, and addition of UV radiation (280 to 400 nm) can increase or down-regulate such inhibition, since solar UV-B (280 to 315 nm) radiation often harms algal cells, while UV-A (315 to 400 nm) at moderate levels stimulates photosynthetic carbon fixation in both phytoplankton and macroalgae. In view of warming effects, increased temperatures have been shown to enhance photorepair of UV-damaged molecules, though it simultaneously enhances respiratory carbon loss. The net effects of ocean acidification on marine primary producers are therefore largely dependent on the photobiological conditions (light limitation, light or UV stress), as well as interactions with rising temperature and other variables such as altered nutrient availability. Hence, feedbacks between changing carbonate chemistry and solar radiation across the entire spectrum present complications to interpret and understand ocean acidification effects based on single-factor experiments. © Inter-Research 2012. Source


Meggers E.,University of Marburg | Meggers E.,Xiamen University
Chemical Communications | Year: 2015

Visible light driven organic chemistry has sparked much excitement over the last several years. This review summarizes recent progress in combining visible light activation with asymmetric catalysis, processes that are either mediated by photoinduced electron or energy transfer. The tasks of photoactivation and asymmetric catalysis are typically accomplished by dual catalyst systems but several recent reports demonstrate that they can also be effectively executed by single catalysts. Beyond the discovery of novel asymmetric transformations under mild reaction conditions, this contemporary area of organic chemistry holds promise for the development of economical and environmentally friendly methods for the asymmetric synthesis of chiral compounds. This journal is © The Royal Society of Chemistry 2015. Source