Guangzhou, China

South China Normal University is a comprehensive university in Guangzhou, capital of Guangdong province, in the People's Republic of China. The university is featured distinctively by both teaching and research, consisting of diverse branches of learning such as philosophy, economics, law, education, literature, history, science, technology, and management. There is also an elementary school in this university. Wikipedia.


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Patent
Shenzhen Guohua Optoelectronics Co., South China Normal University and Shenzhen Guohua Optoelectronics Institute | Date: 2014-04-22

A display structure having a high-brightness diffuse reflector, an electrowetting display structure based on the display structure, an in-cell type electrowetting display structure and a manufacturing method thereof are disclosed. The display structure comprises panel glass (1), a display layer (2) and substrate glass (3), wherein a high-brightness diffuse reflection polymer thin film material (4) is arranged under the substrate glass (3); the panel glass (1), the display layer (2), the substrate glass (3) and the diffuse reflection polymer thin film material (4) are stacked in sequence. According to the display structure and manufacturing method thereof of the invention, the required diffuse reflection and contrast ratio approximate to paper can be provided by placing a high-brightness diffuse reflection polymer thin film under a substrate or a display layer of a plate display structure as a diffuse reflection layer or a diffuse reflector.


Patent
Shenzhen Guohua Optoelectronics Co., South China Normal University and Shenzhen Guohua Optoelectronics Institute | Date: 2014-04-22

A display structure having a paper effect. The display structure comprises panel glass (1), a display layer (2) and substrate glass (3), wherein a paper layer (4) is provided under the substrate glass, and the panel glass (1), the display layer (2), the substrate glass (3) and the paper layer (4) are stacked in sequence. Also provided are an electrowetting display structure based on the display structure and a method for manufacturing the display structure having a paper effect. A piece of high-quality paper is placed under a substrate of the existing display structure as a diffuse reflection layer or a diffuse reflector, so as to provide required diffuse reflection and contrast approximate to paper. Compared with vacuum coating, the process is simpler, and avoids the expensive vacuum coating process, thereby greatly reducing manufacturing costs.


Patent
South China Normal University, Shenzhen Guohua Optoelectronics Co. and Shenzhen Guohua Optoelectronics Institute | Date: 2017-01-11

An oil puncture controlled starting system for an EFD apparatus and manufacturing method therefor, wherein the EFD display structure comprises a base arranged below a lower electrode, and the base is provided with a step, such that a first liquid has a first thickness outside the step and a second thickness on the step, which is less than the first thickness, such a thickness difference renders the first liquid on the step to be punctured by a second liquid firstly when a lower voltage is applied between a upper electrode and the lower electrode, and the first liquid is pushed by the second liquid to move from a first area to a second area.


Patent
Shenzhen Guohua Optoelectronics Co., South China Normal University and Shenzhen Guohua Optoelectronics Institute | Date: 2017-03-01

A display structure having a paper effect. The display structure comprises panel glass (1), a display layer (2) and substrate glass (3), wherein a paper layer (4) is provided under the substrate glass, and the panel glass (1), the display layer (2), the substrate glass (3) and the paper layer (4) are stacked in sequence. Also provided are an electrowetting display structure based on the display structure and a method for manufacturing the display structure having a paper effect. A piece of high-quality paper is placed under a substrate of the existing display structure as a diffuse reflection layer or a diffuse reflector, so as to provide required diffuse reflection and contrast approximate to paper. Compared with vacuum coating, the process is simpler, and avoids the expensive vacuum coating process, thereby greatly reducing manufacturing costs.


Patent
Shenzhen Guohua Optoelectronics Co., South China Normal University and Shenzhen Guohua Optoelectronics Institute | Date: 2017-03-01

A display structure having a high-brightness diffuse reflector, and an electrowetting display structure based on the display structure, an in-cell type electrowetting display structure and a manufacturing method thereof. The display structure comprises panel glass (1), a display layer (2) and substrate glass (3), wherein a high-brightness diffuse reflection polymer thin film material (4) is arranged under the substrate glass (3); the panel glass (1), the display layer (2), the substrate glass (3) and the diffuse reflection polymer thin film material (4) are stacked in sequence. According to the display structure and manufacturing method thereof of the invention, the required diffuse reflection and contrast ratio approximate to paper can be provided by placing a high-brightness diffuse reflection polymer thin film under a substrate or a display layer of a plate display structure as a diffuse reflection layer or a diffuse reflector. The process of the invention is simpler compared with vacuum coating process which can be avoided, thereby greatly reducing the manufacturing cost.


Gao T.-F.,Shenyang Normal University | Ai B.-Q.,South China Normal University | Zheng Z.-G.,Huaqiao University | Chen J.-C.,Xiamen University
Journal of Statistical Mechanics: Theory and Experiment | Year: 2016

Traditionally, time delay in overdamped Brownian ratchet systems reduces the rectified transport. Strikingly, in our delayed feedback ratchets, which are alternatively switched on and off in dependence of the state of the system, time delay can have significant positive-effects that the average velocity of the coupled ratchets are improved with the presence of the delayed time. Moreover, the anomalous transport can arise and then the negative mobility phenomenon appears by changing the bias force. Meanwhile, the bias force F can facilitate Stokes efficiency of delayed feedback ratchets in the anomalous transport region. Remarkably, it is interesting to find that the coupled ratchets can acquire a series of resonant steps that are induced by frequency locking. More importantly, the optimal delay time can also facilitate Stokes efficiency. The theoretical results may provide a new operating technique in which micro- and nano-motor performance could be improved by the state or information of the delayed feedback coupled ratchets. © 2016 IOP Publishing Ltd and SISSA Medialab srl.


Qin J.,South China Normal University | Zeng H.,South China Normal University | Zeng H.,South China University of Technology
Applied Catalysis B: Environmental | Year: 2017

To make the best and highest use of broad spectrum solar energy remains a tremendous challenge and the main target in the photocatalytic area. A novel promising photocatalyst supported on surface plasmon resonance of Ag nanoparticles (NPs) and upconversion photoluminescence property from carbon quantum dots (CQDs) is reported to improve broad spectrum absorption and photoinduced charge transfer of graphitic carbon nitride (g-C3N4) in the photo-driven H2 production for the first time. Here the new-styled nanocomposites not only have more prominent UV–vis photocatalytic ability, also can harness near-infrared light to trigger hydrogen evolution in aqueous solution. Meanwhile, Ag NPs and CQDs serve as electron-reservoirs, which stimulate the separation of photo-generated electron-holes, enhancing quantum efficiency of g-C3N4. Remarkably, the most notable photocatalytic hydrogen generation as high as 626.93 μmol g−1 h−1 under visible light, which is about 6.7 and 2.8 times higher than pure g-C3N4 and the best CQDs/g-C3N4 composite respectively, was achieved upon 6 mL CQDs/g-C3N4 (6CCN) loaded with 3 wt% Ag. Moreover, a facile method is designed to prepare Ag/CQDs/g-C3N4 photocatalysts, and their chemical composition, morphologies, optical properties and stability were characterized methodically. © 2017 Elsevier B.V.


Zhu D.,South China Normal University
Journal of Computational and Theoretical Nanoscience | Year: 2016

In the existing technology, there are no methods or systems that can combine the virtual chemical experiment system with the remote one, although few scientists have used the virtual chemical experiment system together with the remote one. This paper provides the virtual-remote chemical experiment method and system that combines the virtual chemical experiment system with the remote one based on computer chemistry and Internet of Things, compares the method with other alternative methods, and concludes that the virtual-remote chemical experiment method and system is the best one. This paper also provides the cross-system chemical experiment operation encoding and decoding technology and the Internet of Things technology for the proposed method and system. Through the virtual-remote chemical experiment method and system, the workload of scientists and the experiment time can be significantly reduced. Copyright © 2016 American Scientific Publishers All rights reserved.


Dong R.,South China Normal University | Hu Y.,South China University of Technology | Wu Y.,South China University of Technology | Gao W.,University of California at Berkeley | And 3 more authors.
Journal of the American Chemical Society | Year: 2017

Light-driven synthetic micro-/nanomotors have attracted considerable attention due to their potential applications and unique performances such as remote motion control and adjustable velocity. Utilizing harmless and renewable visible light to supply energy for micro-/nanomotors in water represents a great challenge. In view of the outstanding photocatalytic performance of bismuth oxyiodide (BiOI), visible-light-driven BiOI-based Janus micromotors have been developed, which can be activated by a broad spectrum of light, including blue and green light. Such BiOI-based Janus micromotors can be propelled by photocatalytic reactions in pure water under environmentally friendly visible light without the addition of any other chemical fuels. The remote control of photocatalytic propulsion by modulating the power of visible light is characterized by velocity and mean-square displacement analysis of optical video recordings. In addition, the self-electrophoresis mechanism has been confirmed for such visible-light-driven BiOI-based Janus micromotors by demonstrating the effects of various coated layers (e.g., Al2O3, Pt, and Au) on the velocity of motors. The successful demonstration of visible-lightdriven Janus micromotors holds a great promise for future biomedical and environmental applications. © 2017 American Chemical Society.


Chen W.,South China Normal University | Ling S.,South China Normal University
Computer Journal | Year: 2017

Cycle embedding in networks is one of the fundamental algorithmic issues in interconnection networks. Biswapped networks are a family of composite interconnection networks, applicable to constructing massive parallel computers owing to their attractive attributes. Specifically, each biswapped network is built by taking 2n copies of some n-node factor network as modules and connecting them in a simple inter-module connectivity rule. In this paper, the problem of embedding cycles of various lengths in a biswapped network is investigated based on a given cycle of length l ≥ 3 in its factor network. We propose a simple method to address the problem. Using the method, one easily constructs cycles of all even lengths ranging from 8 to 2l2, and also cycles of all odd lengths ranging from l + 6 to 2l2-1 for l being odd in the biswapped network. Together with the known property that a biswapped network inherits the node-symmetry of its factor network, these results indicate that if an n-node factor network is Hamiltonian, then the biswapped network enjoys 8-node-bipancyclicity, and also (n+5)-node-pancyclicity for n being odd. The basic technique behind our method comes from the observation that a cycle of a given length in the biswapped network can be constructed from two associated combined closed walks in the factor network. By constructing combined closed walks of different lengths in the factor network, we can build cycles of various lengths in the biswapped network. Our technique also can be used for embedding cycles in other composite networks, such as swapped networks and Cartesian product networks. © 2016 The British Computer Society. All rights reserved.


Yang D.,South China Normal University
Mathematical Methods in the Applied Sciences | Year: 2017

We consider smooth compactly supported solution to the classical Vlasov-Poisson system in three space dimensions in the electrostatic case. An estimate on velocities is derived, showing a growth rate at most like the power 1/8 of the time variable. As a consequence, a better decay estimate is obtained for the electric field in the L∞ norm. © 2017 John Wiley & Sons, Ltd.


Chen Y.,South China Normal University | Wu H.,South China Normal University | Xie H.,South China Normal University
Mathematics in Computer Science | Year: 2017

The main results of this paper is to give a complete characterization of the automaticity of one-relator semigroups with length less than or equal to three. Let S= sgp⟨ A| u= v⟩ be a semigroup generated by a set A={a1,a2,…,an},n∈N with defining relation u= v, where u, v∈ A∗ and A∗ is the free monoid generated by A. Such a semigroup is called a one-relator semigroup. Suppose that | v| ≤ | u| ≤ 3 , where |u| is the length of the word u. Suppose that a,b∈A,a≠b. Then we have the following: (1) S is prefix-automatic if u=v∉{aba=ba,aab=ba,abb=bb}. Moreover, if u=v∈{aba=ba,aab=ba,abb=bb} then S is not automatic. (2) S is biautomatic if one of the following holds: (i) |u|=3,|v|=0, (ii) | u| = | v| = 3 , (iii) | u| = 2 and u=v∉{ab=a,ab=b}. Moreover, if u=v∈{ab=a,ab=b} then S is not biautomatic. © 2017, Springer International Publishing.


Zhang S.,South China Normal University | Wang X.,South China Normal University
Plant Signaling and Behavior | Year: 2017

GASA proteins are characterized by an N-terminal signal peptide and a C-terminal conserved GASA domain with 12 invariant cysteine residues. Despite being widely distributed among plant species, their functions are not completely elucidated and little is known about their mechanism of action. This review focuses on the current knowledge about the molecular structure, protein subcellular localization and phytohormones responses of this up-and-coming family of peptides. Furthermore, we discussed the roles of GASA proteins in plant growth and development, plant responses to biotic or abiotic stresses and their participation in phytohormonal signaling integration. © 2017 Taylor & Francis Group, LLC.


Ai B.-Q.,South China Normal University | Li F.-G.,South China Normal University
Soft Matter | Year: 2017

We study the rectified transport of underdamped active noninteracting particles in an asymmetric periodic potential. It is found that the ratchet effect of active noninteracting particles occurs in a single direction (along the easy direction of the substrate asymmetry) in the overdamped limit. However, when the inertia is considered, it is possible to observe reversals of the ratchet effect, where the motion is along the hard direction of the substrate asymmetry. By changing the friction coefficient or the self-propulsion force, the average velocity can change its direction several times. Therefore, by suitably tailoring the parameters, underdamped active particles with different self-propulsion forces can move in different directions and can be separated. © The Royal Society of Chemistry.


Pang S.,South China Normal University | Chen L.,Sun Yat Sen University
Xitong Gongcheng Lilun yu Shijian/System Engineering Theory and Practice | Year: 2016

We investigate the effects of de jure and de facto measures of financial openness on the economic growth, the role of domestic economic development and international economic and financial variables on the effect of financial openness by utilizing bounds testing approach and employing time series data from 1979 to 2013. We find that both financial deregulations on cross-border transactions and expansion of cross-border financial transactions have the positive effects on the economic growth, but the effects diminish with time, increase of physical capital, financial development and improvements of human capital. Further, financial openness can lower the impact of world production, interest rate and the price of crude oil on economic growth. Finally, we also find that physical capital have the significant impacts on the economic growth while human capital is an emerging impetus to the economic development, but financial development and population growth do not have the promotion effects on the economic growth. © 2016, Editorial Board of Journal of Systems Engineering Society of China. All right reserved.


Wei C.-P.,South China Normal University | Yu Y.-F.,South China Normal University | Zhang Z.-M.,South China Normal University
International Journal of Theoretical Physics | Year: 2017

We propose a multi-mode nonlinear interferometer and study its phase sensitivity for two, three and four modes with single photons as inputs. We find that the phase sensitivity of the nonlinear interferometers can be improved by increasing the nonlinear index k. And when the total number of the input photons is fixed, increasing the number of modes is detrimental to the phase sensitivity. © 2017 Springer Science+Business Media New York


Wu B.,South China Normal University | Duan T.,Lanzhou University of Finance and Economics
Physica A: Statistical Mechanics and its Applications | Year: 2017

The price of gold future is affected by many factors, which include the fluctuation of gold price and the change of trading environment. Fractal analysis can help investors gain better understandings of the price fluctuation and make reasonable investment decisions in the gold future market. After analyzing gold future price from January 2th, 2014 to April 12th, 2016 at the Shanghai Futures Exchange (SFE) in China, the conclusion is drawn that the gold future market has sustainability in each trading day, with all Hurst indexes greater than 0.5. The changing features of Hurst index indicate the sustainability of gold future market is strengthened first and weakened then. As a complicatedly nonlinear system, the gold future market can be well reflected by Elman neural network, which is capable of memorizing previous prices and particularly suited for forecasting time series in comparison with other types of neural networks. After analyzing the price trend in the gold future market, the results show that the relative error between the actual value of gold future and the predictive value of Elman neural network is smaller. This model that has a better performance in data fitting and predication, can help investors analyze and foresee the price tendency in the gold future market. © 2017 Elsevier B.V.


Ai B.-Q.,South China Normal University | He Y.-F.,Hebei University | Zhong W.-R.,New Energy Technologies
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2017

Directed transport of self-propelled particles is numerically investigated in a three-dimensional asymmetric potential. Beside the steric repulsive forces, hydrodynamic interactions between particles have been taken into account in an approximate way. From numerical simulations, we find that hydrodynamic interactions can strongly affect the rectified transport of self-propelled particles. Hydrodynamic interactions enhance the performance of the rectified transport when particles can easily pass across the barrier of the potential, and reduce the rectified transport when particles are mainly trapped in the potential well. © 2017 American Physical Society.


Li Y.T.,South China Normal University | Yang L.T.,South China Normal University | Zhang H.,South China Normal University
IOP Conference Series: Materials Science and Engineering | Year: 2017

In this paper, a novel bio-based resin was prepared by the radical copolymerization of maleated soybean oil polyols (MSBOP) and styrene (ST). Structure of the product was studied by Fourier transformation infrared spectrometer (FT-IR), and the result was found to be consistent with that of theoretical structure. Swelling experiments indicated that the crosslinking degree increased with the increase of hydroxyl value. Thermal analysis by differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TG) revealed that glass transition temperature (Tg) of the polymer increased with increasing hydroxyl values, and that its thermal stability showed a good correlation with the hydroxyl value. The tensile strength and impact strength were significantly affected by the hydroxyl value of soybean oil polyols. With increasing hydroxyl value, the tensile strength presented an increasing trend, while the impact strength showed a decreasing one. Moreover, the property of the polymer from elastomer to plastic character also depended on the functionality of the hydroxyl value of soybean oil polyols. © Published under licence by IOP Publishing Ltd.


Fan X.-L.,South China Normal University | Kou K.I.,University of Macau | Liu M.-S.,South China Normal University
Signal Processing | Year: 2017

The quaternion linear canonical transform (QLCT), a generalization of the classical 2D Fourier transform, has gained much popularity in recent years because of its applications in many areas, including color image and signal processing. There are relationship between Wigner distribution and ambiguity function. But, these relations are only suitable for complex-valued signals, and have not been investigated in quaternion linear canonical transforms. The purpose of this paper is to propose an equivalent relationship for the quaternion Wigner distribution and quaternion ambiguity function in the QLCT setting. First, we propose the 2D quaternion Wigner distribution (QLWD) and quaternion ambiguity function associated with the QLCT. Next, the relationship between these two novel concepts are derived. Moreover, the connection with the corresponding analytic signal are investigated. Examples with bandpass analytic signal illustrate the features of the proposed distributions. Finally a novel algorithm for the detection of quaternion-valued linear frequency-modulated signal is presented by using the proposed QLWD. © 2016 Elsevier B.V.


Chen Z.,South China Normal University | Qiao W.,South China Normal University
Optics InfoBase Conference Papers | Year: 2016

We have developed supercontinuum-laser-based optical-resolution multispectral photoacoustic microscopy which has the desirable properties of being compact, low-cost. The phantom and in vivo experiment results have demonstrated the photoacoustic microscopy system can accomplish label-free microvasculature imaging. © OSA 2016.


Ji Z.,South China Normal University | Ding W.,South China Normal University
Optics InfoBase Conference Papers | Year: 2016

We developed a photoacoustic (PA) tomography system based on a full-ring transducer array and a parallel data acquisition system. In addition to rapid imaging, the position of the imaging plane can also be recognized. © OSA 2016.


Yang F.,South China Normal University | Yang S.,South China Normal University
Optics InfoBase Conference Papers | Year: 2016

Based on the thermoelastic and viscoelasticity damping effect, we propose a photoacoustic method for the elastic modulus and viscosity coefficient measurement. Elasticity and viscosity imaging of phantom sample indicates feasibility of method and imaging performance. © OSA 2016.


Ji Z.,South China Normal University | Yang S.,South China Normal University | Xing D.,South China Normal University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

Microwave-induced thermoacoustic (TA) imaging combines the advantages of high imaging contrast due to electromagnetic absorption and high resolution of the ultrasound technology, and it is a potential alternative imaging technique for biomedical applications, particularly for breast tumor detection. The traditional TA system uses circular-scanning (CS) to obtain complete information to reconstruct a two-dimensional image, however, it needs a large operating space for rotation of the transducers and bulk of coupling medium limiting its medical applications. The linear-scanning (LS) system can overcome these problems partially but usually lose some information and cause image distortion. In this paper, in order to overcome above limitations, a TA imaging system with Sample-Cling-Scanning (SCS) model based on a flexible multi-element transducer is presented. It combines the advantages of both CS and LS modes, and overcome their limitations. Meanwhile, an adaptive back projection algorithm is presented to implement this scanning model. The experimental results show that the proposed system combines advantages including shape adaptation, information integrity, and efficient transmission. These advantages make it a preferred system for TA applications, especially in breast tumor detection. © 2016 SPIE.


Chen Y.-S.,Yuan Ze University | Zhou C.-Y.,South China Normal University | Li L.-Y.,South China Normal University
2016 IEEE International Conference on Systems, Man, and Cybernetics, SMC 2016 - Conference Proceedings | Year: 2016

Dichromats (a human with red-green color blindness considered in this paper) cannot always perceive meaningful visual information due to their deficiencies in eye cells. Stroke information extraction from a color-blindness image (CBI) is presented in order to deliver direct and effective information to dichromats. A CBI is first transformed into the pattern-highlighted image by means of color component analysis, pattern attention as well as thresholding. Then the maximal effective information in the highlighted image is computed to form a gray image. Based on the assistance of gray thinning algorithm, the useful stroke information in CBI is obtained. Experimental results on the often-used Ishihara test plates confirm that the perceived stroke information agrees with the normal perception. © 2016 IEEE.


Gan W.,South China Normal University | Fang Z.,South China Normal University
Journal of Fisheries of China | Year: 2016

Biological sex differentiation and hormonal regulation are related with the expression of CYP19 gene in teleost, and so it can be used to explore the relationship between environmental hormone pollution and gene expression. The Gambusia affinis CYP19a cDNA of full sequence was cloned and analyzed for the first time. This would provide comprehensive experimental data for the study of the CYP19 gene as a biomarker for monitoring environmental hormones. Primers were designed according to the conserved region of CYP19a cDNA, and the conserved region was amplified and sequenced. RACE method was used to amplify the G. affinis CYP19a cDNA of full sequence and its protein sequence homology analysis, and the RT-PCR method was used to detect the transcription level of CYP19a mRNA in the sequence. The full length cDNA sequence of G. affinis CYP19a type was cloned. This sequence contains 2020 bp nucleotides and codes 518 amino acids with an open reading frame (ORF) from 238 bp to 1791 bp. We made an analysis of the signal peptide, transmembrane helices, hydrophilic/hydrophobic, primary structure, secondary structure and tertiary structure. When making the homology comparison with CYP19a gene in gonads of other teleost, the gene fragment similarity of mosquitofish were 93%, 84%, 84%, 71%, 71% and 66% with Fundulus heteroclitus, Oryzias laticeps, Rhabdosargus sarba, Carassius auratus, Cyprinus carpio and Danio rerio respectively. This showed that the cloned gene was G. affinis CYP19a gene. Phylogenetic analysis of the CYP19 gene by using MEGA4.0 indicates that CYP19a gene is highly conserved when clustered with other 19 species ovary-derived P450arom gene. We identified the CYP19a cDNA of full sequence is gonadal aromatase gene, and the proof of G. affinis aromatase is by two genes of CYP19a and CYP19b encoding. G. affinis CYP19a has 3 highly conserved fragments, and has catalytic activity.


Xiao X.,South China Normal University | Wang W.,South China Normal University | Zhang Y.,South China Normal University | Jia L.,South China Normal University
Journal of Pharmaceutical and Biomedical Analysis | Year: 2017

Monoclonal antibodies (mAbs) are one of the most promising classes of therapeutic protein biopharmaceuticals. However, the complexity of mAbs poses a daunting analytical challenge for heterogeneity characterization of mAbs. In this study, inspired by blood coagulation, we adopted a fibrin coating as a novel stationary phase in open tubular (OT) column for the separation of the mAbs variants by capillary electrochromatography. The fibrin coating was prepared by in situ polymerization of fibrin in the presence of thrombin as a catalyst inside a fused-silica capillary. Scanning electron microscopy and electroosmotic flow measurement were carried out to characterize the fibrin coated OT columns. The average thickness of the fibrin coating was about 1.13. μm. And the EOF of the column was pH-dependent. The electrochromatographic performance of the prepared columns was evaluated by characterization of the variants of three mAbs (cetuximab, trastuzumab and rituximab). The columns demonstrated good repeatability with the run-to-run, day-to-day and column-to-column relative standard deviations of migration times less than 2.42%. The study highlighted the potential of adsorbed proteins as stationary phases for the separation of mAbs variants. Furthermore, the study provided a new platform for characterization of heterogeneity of mAbs in pharmaceutical industry. © 2017 Elsevier B.V.


Chen Z.,South China Normal University | Yang S.,South China Normal University | Xing D.,South China Normal University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

We have developed a multimodality imaging system by optically integrating all-optical photoacoustic microscopy (AOPAM), optical coherence tomography (OCT) and fluorescence microscopy (FLM) to provide complementary information including optical absorption, optical back-scattering and fluorescence contrast of biological tissue. By sharing the same low-coherence Michelson interferometer, AOPAM and OCT could be organically optically combined to obtain the absorption and scattering information of the biological tissues. Also, owing to using the same laser source and objective lens, intrinsically registered photoacoustic and fluorescence signals are obtained to present the radiative and nonradiative transition process of absorption. Simultaneously photoacoustic angiography, tissue structure and fluorescence molecular in vivo images of mouse ear were acquired to demonstrate the capabilities of the optically integrated trimodality imaging system, which can present more information to study tumor angiogenesis, vasculature, anatomical structure and microenvironments in vivo. © 2016 SPIE.


Mei F.,South China Normal University | Mei F.,National University of Singapore | Zhu S.-L.,South China Normal University | Zhang Z.-M.,South China Normal University | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We propose an experimental scheme to simulate and detect the properties of time-reversal invariant topological insulators, using cold atoms trapped in one-dimensional bichromatic optical lattices. This system is described by a one-dimensional Aubry-Andre model with an additional SU(2) gauge structure, which captures the essential properties of a two-dimensional Z 2 topological insulator. We demonstrate that topologically protected edge states, with opposite spin orientations, can be pumped across the lattice by sweeping a laser phase adiabatically. This process is an elegant way to transfer topologically protected quantum states in a highly controllable environment. We discuss how density measurements could provide clear signatures of the topological phases emanating from our one-dimensional system. © 2012 American Physical Society.


Li F.,Hong Kong Polytechnic University | Li Q.,Peking University | Yuan J.,Hong Kong Polytechnic University | Yuan J.,South China Normal University | And 2 more authors.
Optics Express | Year: 2014

The low coherence of the supercontinuum (SC) generated using picosecond pump pulses is a major drawback of such SC generation scheme. In this paper, we propose to first self-similarly compress a high power picosecond pump pulse by injecting it into a nonlinearity increasing fiber. The compressed pulse is then injected into a non-zero dispersionshifted fiber (NZ-DSF) for SC generation. The nonlinearity increasing fiber can be obtained by tapering a large mode area photonic crystal fiber. The fiber nonlinearity is varied by varying the pitch sizes of the air holes. By using the generalized nonlinear Schrödinger equation, we show that a 1 ps pump pulse with random noise can be compressed self-similarly down to a pulse width of 53.6 fs with negligible pedestal. The noise level of the compressed pulse is reduced at the same time. The 53.6 fs pulse can then be used to generate highly coherent SC in an NZ-DSF. By using the proposed scheme, the tolerance of noise level for highly coherent SC generation with picosecond pump pulses can be improved by 5 order of magnitude. ©2014 Optical Society of America


Tang D.,Guangdong Pharmaceutical University | Tang D.,South China University of Technology | Cai Y.,Guangdong Pharmaceutical University | Cai Y.,University of Texas at Dallas | And 2 more authors.
Information Sciences | Year: 2014

Quantum-behaved particle swarm optimization (QPSO), a novel variant of PSO inspired by quantum mechanics, is a global convergence guaranteed algorithm, which outperforms the original PSO in search ability and has fewer parameters to control. But as many other PSOs, it is easy to fall into local optimum in solving high-dimensional complex optimization problems. This paper proposes an improved QPSO algorithm for continuous non-linear large scale problems based on memetic algorithm and memory mechanism. The memetic algorithm is used to make all particles (each particle corresponding to a memetic) gain some experience through a local search before being involved in the evolutionary process, and the memory mechanism is used to introduce a so-called 'bird kingdom' with memory capacity, both of which can improve the global search ability of the algorithm. Another difference compared to the previous QPSOs is that we let each dimension of a particle update with the same random number, thus increasing the speed of convergence and enhancing the ability of local search. Numerical experiments are conducted to compare the proposed algorithm with different variants of PSO and other swarm intelligence algorithms. The experimental results show the superiority of the proposed approach on benchmark test functions. © 2014 Elsevier Inc. All rights reserved.


Li Y.,South China Normal University | Zheng Y.,South China Normal University | Wang Q.,South China Normal University | Zhang C.C.,University of Texas at Dallas
Materials Chemistry and Physics | Year: 2012

The innovative hydrogel template (polyacrylamide or polyacrylic acid) directed synthesis of YVO 4:Eu 3+ phosphor in a controlled manner was thoroughly studied. Photoluminescence spectra show the europium(III)-doped yttrium orthovanadate could exhibit strong red emissions within the soft matrix (polyacrylamide) and remain relatively stable even when the temperature reached nearly 100°C. After calcination process, X-ray powder diffraction patterns, SEM and DLS measurements implied that the sample was in agreement with pure tetragonal phase and the particle sizes were in the range of 100-200 nm. More importantly, YVO 4:Eu 3+ products prepared based on hydrogels have remarkable improvement in emission intensities compared to phosphors synthesized by conventional approach. Similar results of overall quantum efficiency also support that YVO 4:Eu 3+ assembled by PAM hydrogel (1.94%) is better than the routine way (0.91%). © 2012 Elsevier B.V. All rights reserved.


Li Y.,Beijing Normal University | Ding G.,Beijing Normal University | Booth J.R.,Northwestern University | Huang R.,South China Normal University | And 4 more authors.
Human Brain Mapping | Year: 2012

Previous studies have shown that white matter in the deaf brain changes due to hearing loss. However, how white-matter development is influenced by early hearing experience of deaf people is still unknown. Using diffusion tensor imaging and tract-based spatial statistics, we compared white-matter structures among three groups of subjects including 60 congenitally deaf individuals, 36 acquired deaf (AD) individuals, and 38 sex- and age-matched hearing controls (HC). The result showed that the deaf individuals had significantly reduced fractional anisotropy (FA) values in bilateral superior temporal cortex and the splenium of corpus callosum compared to HC. The reduction of FA values in acquired deafness correlated with onset age of deafness, but not the duration of deafness. To explore the underlying mechanism of FA changes in the deaf groups, we further analyzed radial and axial diffusivities and found that (1) the reduced FA values in deaf individuals compared to HC is primarily driven by higher radial diffusivity values and (2) in the AD, higher radial diffusivity was correlated with earlier onset age of deafness, but not the duration of deafness. These findings imply that early sensory experience is critical for the growth of fiber myelination, and anatomical reorganization following auditory deprivation is sensitive to early plasticity in the brain. © 2010 Wiley Periodicals, Inc.


Zhu Q.,Ningbo University | Yang X.,Honghe University | Wang H.,South China Normal University
Journal of the Franklin Institute | Year: 2010

In this paper we study stochastic stability of delayed recurrent neural networks with both Markovian jump parameters and nonlinear disturbances. Based on the Lyapunov stability theory, the properties of a Brownian motion, the generalized It's formula and linear matrix inequalities technique, some new delay-dependent conditions are derived to guarantee the stochastically asymptotic stability of the trivial solution or zero solution. In particular, the activation functions in this paper depend on Markovian jump parameters and they are more general than those usual Lipschitz conditions. Also, time delays proposed in this paper comprise both constant delays and time-varying delays. Moreover, the derivative of time delays is allowed to take any value. Therefore, the results obtained in this paper are less conservatism and generalize those given in the previous literature. Finally, two numerical examples and their simulations are used to show the effectiveness of the obtained results. © 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.


Sun P.C.,Beijing Normal University | Wu Y.L.,Beijing Normal University | Gao J.W.,South China Normal University | Cheng G.A.,Beijing Normal University | And 2 more authors.
Advanced Materials | Year: 2013

A large contrast in the electrical and thermal conductivities via a first order phase transition in surface-functionalized carbon nanotube(CNT)/hexadecane composites is reported. Surface modification of the CNTs improves the electrical conductivity contrast and the stability of the composites. We demonstrate that, with these composites, the electrical conductivity changes above 105 times and the thermal conductivity varies up to 3 times at 18 °C. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Guo Y.Y.,Nanjing University | Liu H.M.,Nanjing University | Yu D.P.,Peking University | Liu J.-M.,Nanjing University | And 2 more authors.
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

The effect of Sr/Ti nonstoichiometry on the ferroelectricity and magnetism in polycrystalline SrTiO 3 is investigated by the dielectric, ferroelectric, Raman, and magnetic characterizations. It revealed that the nonstoichiometric SrTiO 3 exhibits both ferroelectric polarization and superparamagnetism, which increase with the degree of nonstoichiometry. It is argued that the antisite-like defects with net local dipoles and magnetic moments contribute to the ferroelectricity and superparamagnetism, confirmed by the first-principles calculations. © 2012 American Physical Society.


Hu S.,Beijing Normal University | Jin H.,South China Normal University | Chen Z.,Jinan University | Mo L.,South China Normal University | Liu J.,Beijing Normal University
Cortex | Year: 2013

Previous functional magnetic resonance imaging (fMRI) studies have identified several regions in the ventral visual pathway that are specialized for processing faces, words and general objects. However, little is known about the origin of the functional selectivity of these regions. Here, we reported a pediatric patient who suffered a left occipitoparietal lesion in the first year after birth from a subdural hematoma. After the hematoma was removed at the age of six, the hemianopia in the right visual field was alleviated, and no obvious deficits in low-level vision were observed in the patient at the age of twelve. In line with the behavioral observations, meridian mappings with fMRI showed that the early visual cortex of the left hemisphere was significantly activated, which was similar to that of the intact right hemisphere. However, the left ventral temporal cortex failed to show selective responses for faces, words and objects, which were in contrast to the normal selective responses for these objects in the right counterpart. Therefore, it is likely that the development of object selectivity in the ventral temporal cortex depends on visual inputs from the early visual cortex at an early age. © 2013 Elsevier Ltd.


Tang B.,Guangdong University of Technology | Yu G.,Guangdong University of Technology | Fang J.,South China Normal University | Shi T.,Sun Yat Sen University
Journal of Hazardous Materials | Year: 2010

An emulsion liquid membrane (ELM)-crystallization process, using hypophosphorous acid as a reducing agent in the internal aqueous phase, has been developed for the purpose of recovering high-purity silver directly from dilute industrial effluents (waste rinse water). After pretreatment with HNO 3, silver in waste rinse water can be reliably recovered with high efficiency through the established process. The main parameters in the process of ELM-crystallization include the concentration of carrier in the membrane phase, the concentration of reducing agent in the internal aqueous phase, and the treatment ratio, which influence the recovery efficiency to various extents and must be controlled carefully. The results indicated that more than 99.5% (wt.) of the silver ions in the external aqueous phase were extracted by the ELM-crystallization process, with an average efficiency of recovery of 99.24% (wt.) and a purity of 99.92% (wt.). The membrane phase can be used repeatedly without loss of the efficiency of recovery. © 2009 Elsevier B.V.


Yi Z.,South China Normal University | Yi Z.,Ocean University of China | Katz L.A.,Smith College | Song W.,South China Normal University | Song W.,Ocean University of China
PLoS ONE | Year: 2012

The current understanding of ciliate phylogeny is mainly based on analyses of a single gene, the small subunit ribosomal RNA (SSU-rDNA). However, phylogenetic trees based on single gene sequence are not reliable estimators of species trees, and SSU-rDNA genealogies are not useful for resolution of some branches within Ciliophora. Since congruence between multiple loci is the best tool to determine evolutionary history, we assessed the usefulness of alpha-tubulin gene, a protein-coding gene that is frequently sequenced, for ciliate phylogeny. Here, we generate alpha-tubulin gene sequences of 12 genera and 30 species within the order Euplotida, one of the most frequently encountered ciliate clades with numerous apparently cosmopolitan species, as well as four genera within its putative sister order Discocephalida. Analyses of the resulting data reveal that: 1) the alpha-tubulin gene is suitable phylogenetic marker for euplotids at the family level, since both nucleotide and amino acid phylogenies recover all monophyletic euplotid families as defined by both morphological criteria and SSU-rDNA trees; however, alpha-tubulin gene is not a good marker for defining species, order and subclass; 2) for seven out of nine euplotid species for which paralogs are detected, gene duplication appears recent as paralogs are monophyletic; 3) the order Euplotida is non-monophyletic, and the family Uronychiidae with sequences from four genera, is non-monophyletic; and 4) there is more genetic diversity within the family Euplotidae than is evident from dargyrome (geometrical pattern of dorsal "silverline system" in ciliates) patterns, habit and SSU-rDNA phylogeny, which indicates the urgent need for taxonomic revision in this area. © 2012 Yi et al.


Chen J.,Guangdong University of Technology | Fan G.-H.,South China Normal University | Pang W.,Guangdong University of Technology | Zheng S.-W.,South China Normal University | Zhang Y.-Y.,South China Normal University
IEEE Photonics Technology Letters | Year: 2012

The blue InGaN light-emitting diodes (LEDs) with specific designs of p-InGaN/GaN superlattice (SL) last quantum barrier are investigated numerically and experimentally. The proposed SL with a graded indium mole fraction from 0% to 5% shows improved efficiency droop and superior optical characteristics in comparison with the conventional LEDs. As indicated by the simulation results, the promotion of hole injection and the reduction of electron leakage play important roles in these improvements. Fabricated LEDs with this specific design exhibit stronger emission intensity, smaller forward voltage, and larger light output power compared to its counterparts. © 2012 IEEE.


Zhang W.,South China Normal University | Zhang W.,China Institute of Technology | Wang X.,Jinan University | Chen T.,South China Normal University
Cellular Signalling | Year: 2012

Our recent study have shown that resveratrol (RV), a natural plant polyphenol found in red grape skins as well as other food product, induced apoptosis via the downstream factors, caspase-independent AIF and to lesser extent caspase-9, of intrinsic apoptosis pathway in human lung adenocarcinoma (ASTC-a-1) cells. This report is designed to explore the roles of the upstream mediators of the intrinsic pathway, such as Bak/Bax, Bim, Puma and Noxa, during RV-induced apoptosis in human lung adenocarcinoma (ASTC-a-1 and A549) cell lines. RV treatment remarkably induced the activation of Bak but not Bax, and silencing Bak but not Bax by shRNA almost completely prevented RV-induced cell death, mitochondrial dysfunction and also largely prevented RV-induced AIF release, demonstrating the preferential engagement of Bak but not Bax during RV-induced apoptosis. In addition, although RV treatment induced a significant degradation of Mcl-1, knockdown of Mcl-1 by shRNA only modestly increased RV-induced Bak activation. Interestingly, silencing Bim but not Puma and Noxa remarkably attenuated RV-induced cell death, loss of mitochondrial membrane potential, and Bak activation, suggesting the important roles of Bim. Collectively, our findings for the first time demonstrate that RV induces apoptosis dominantly via a Bak- but not Bax-mediated AIF-dependent mitochondrial apoptotic signaling pathway in which Bim but not Puma and Noxa may supply the force to trigger Bak activation and subsequent apoptosis in both ASTC-a-1 and A549 cell lines. © 2012 Elsevier Inc..


Talhelm T.,University of Virginia | Zhang X.,Beijing Normal University | Oishi S.,University of Virginia | Shimin C.,South China Normal University | And 3 more authors.
Science | Year: 2014

Cross-cultural psychologists have mostly contrasted East Asia with the West. However, this study shows that there are major psychological differences within China. We propose that a history of farming rice makes cultures more interdependent, whereas farming wheat makes cultures more independent, and these agricultural legacies continue to affect people in the modern world. We tested 1162 Han Chinese participants in six sites and found that rice-growing southern China is more interdependent and holistic-thinking than the wheat-growing north. To control for confounds like climate, we tested people from neighboring counties along the rice-wheat border and found differences that were just as large. We also find that modernization and pathogen prevalence theories do not fit the data.


Huang J.-H.,South China Normal University | Mai Z.-F.,Beijing Normal University
European Physical Journal C | Year: 2016

The superradiant stability is investigated for non-extremal Reissner–Nordström black holes. We use an algebraic method to demonstrate that all non-extremal Reissner–Nordström black holes are superradiantly stable against a charged massive scalar perturbation. This improves the results obtained before for non-extremal Reissner–Nordström black holes. © 2016, The Author(s).


Mo C.,Tsinghua University | Mo C.,Peking University | Yu M.,South China Normal University | Seger C.,Colorado State University | Mo L.,South China Normal University
Brain and Language | Year: 2015

How are Chinese characters recognized and represented in the brain of skilled readers? Functional MRI fast adaptation technique was used to address this question. We found that neural adaptation effects were limited to identical characters in bilateral ventral visual system while no activation reduction was observed for partially overlapping characters regardless of the spatial location of the shared sub-character components, suggesting highly selective neuronal tuning to whole characters. The consistent neural profile across the entire ventral visual cortex indicates that Chinese characters are represented as mutually distinctive wholes rather than combinations of sub-character components, which presents a salient contrast to the left-lateralized, simple-to-complex neural representations of alphabetic words. Our findings thus revealed the cultural modulation effect on both local neuronal activity patterns and functional anatomical regions associated with written symbol recognition. Moreover, the cross-language discrepancy in written symbol recognition mechanism might stem from the language-specific early-stage learning experience. © 2014 The Authors.


Luo L.,Soochow University of China | Zhang L.,Soochow University of China | Dong Y.,Fudan University | Liu T.C.-Y.,South China Normal University
Lasers in Medical Science | Year: 2013

The aim of the present study was to determine the effects of low-level laser therapy (LLLT) on the homeostasis of reactive oxygen species (ROS) and expression of IGF-1 and TGF-β1 in the gastrocnemius muscles of rats following contusion. Muscle regeneration involves cell proliferation, migration, and differentiation and is regulated by growth factors. A growing body of evidence suggests that LLLT promotes skeletal muscle regeneration and accelerates tissue repair. Adult male Sprague-Dawley rats (n = 96) were randomly divided into three groups: control group (no lesion, untreated, n = 6), contusion group (n = 48), and contusion-plus-LLLT group (n = 42). Gallium aluminum arsenide (GaAlAs) laser irradiation (635 nm; beam spot, 0.4 cm 2; output power, 7 mW; power density, 17.5 mW/cm2; 20 min) was administered to the gastrocnemius contusion for 20 min daily for 10 days. Muscle remodeling was evaluated at 0 h and 1, 2, 3, 7, 14, 21, and 28 days after injury. Hematoxylin and eosin and Van Gieson staining were used to evaluate regeneration and fibrosis; muscle superoxide dismutase (SOD) and malondialdehyde (MDA) were detected via biochemical methods; expression of transforming growth factor beta-1 (TGF-β1) and insulin-like growth factor-1 (IGF-1) were investigated via immunohistochemistry. The results showed that LLLT markedly promoted the regeneration of muscle and reduced scar formation. LLLT also significantly enhanced muscle SOD activity and significantly decreased muscle MDA levels 1, 2, and 3 days after injury. LLLT increased the expression of IGF-1 2, 3, and 7 days after injury and decreased the expression of IGF-1 21 and 28 days after injury. LLLT decreased the expression of TGF-β1 3 and 28 days after injury but increased expression at 7 and 14 days after injury. Our study showed that LLLT could modulate the homeostasis of ROS and of the growth factors IGF-1 and TGF-β1, which are known to play important roles in the repair process. This may constitute a new preventive approach to muscular fibrosis. © 2012 Springer-Verlag London Ltd.


Zheng R.,Massachusetts Institute of Technology | Zheng R.,Beijing Normal University | Gao J.,Massachusetts Institute of Technology | Gao J.,South China Normal University | And 6 more authors.
Nano Letters | Year: 2012

Different from the electrical conductivity of conductive composites, the thermal conductivity usually does not have distinctive percolation characteristics. Here we report that graphite suspensions show distinct behavior in the thermal conductivity at the electrical percolation threshold, including a sharp kink at the percolation threshold, below which thermal conductivity increases rapidly while above which the rate of increase is smaller, contrary to the electrical percolation behavior. Based on microstructural and alternating current impedance spectroscopy studies, we interpret this behavior as a result of the change of interaction forces between graphite flakes when isolated clusters of graphite flakes form percolated structures. Our results shed light on the thermal conductivity enhancement mechanisms in nanofluids and have potential applications in energy systems. © 2011 American Chemical Society.


Yu R.,South China Normal University | Yu R.,Peking University | Zhou W.,University of Mississippi Medical Center | Zhou X.,Peking University
PLoS ONE | Year: 2011

Reward probability and uncertainty are two fundamental parameters of decision making. Whereas reward probability indicates the prospect of winning, reward uncertainty, measured as the variance of probability, indicates the degree of risk. Several lines of evidence have suggested that the anterior cingulate cortex (ACC) plays an important role in reward processing. What is lacking is a quantitative analysis of the encoding of reward probability and uncertainty in the human ACC. In this study, we addressed this issue by analyzing the feedback-related negativity (FRN), an event-related potential (ERP) component that reflects the ACC activity, in a simple gambling task in which reward probability and uncertainty were parametrically manipulated through predicting cues. Results showed that at the outcome evaluation phase, while both win and loss-related FRN amplitudes increased as the probability of win or loss decreased, only the win-related FRN was modulated by reward uncertainty. This study demonstrates the rapid encoding of reward probability and uncertainty in the human ACC and offers new insights into the functions of the ACC. © 2011 Yu et al.


Wang Z.-P.,Guangdong Pharmaceutical University | Chen T.-S.,South China Normal University
Progress in Biomedical Optics and Imaging - Proceedings of SPIE | Year: 2013

Hepatocarcinoma, a malignant cancer, threaten human life badly. It is a current issue to seek the effective natural remedy from plant to treat cancer due to the resistence of the advanced hepatocarcinoma to chemotherapy. In this report, we assessed the antitumor activity of a prunellae spica aqueous extract (PSE) in vitro and in vivo. PSE was quantified by HPLC and UV. MTT assay showed that PSE did not effectively inhibit the growth of H22 cells. The in vivo anti-tumor activity was assessed by using the mice bearing H22 tumor. In vivo studies showed the higher antitumor efficacy of PSE without significant side effect assessed by the reduced tumor weight, and the extended survival time of the mice bearing H22 solid and ascites tumor. Collectively, PSE is a promising Chinese medicinal herb for treating hepatocarcinoma. © Copyright SPIE.


Jia X.,Henan Polytechnic University | Wang S.,Beijing Normal University | Qin M.,South China Normal University
New Journal of Physics | Year: 2016

Based on atomic first principles, we predict enhanced thermal spin transfer (TST) effects and small switching temperature gradient in Fe |MgO|Fe |MgO|Fe double-barrier magnetic tunnel junctions (MTJs). At room temperature, temperature gradient δ10 K with ∇T ∼10Knm?1 across barriers would be sufficient to switch the magnetic configurations circularly in a junction with 3MgOatomic layers (L), which is about one order smaller than that in Fe |MgO(3L) |Fe MTJs. This temperature gradient is under the current experimental capability. The resonant quantum-well states in companion with resonant interfacial states are responsible for the enhancement. Moreover, a thermal induced 'off' state is found in a double-barrier MTJ. © 2016 IOP Publishing Ltd.


Lai H.-J.,Sun Yat Sen University | Pan Y.,Sun Yat Sen University | Tang Y.,South China Normal University | Yu R.,Guangdong University of Technology
IEEE Transactions on Neural Networks and Learning Systems | Year: 2013

In recent years, there has been growing interest in learning to rank. The introduction of feature selection into different learning problems has been proven effective. These facts motivate us to investigate the problem of feature selection for learning to rank. We propose a joint convex optimization formulation which minimizes ranking errors while simultaneously conducting feature selection. This optimization formulation provides a flexible framework in which we can easily incorporate various importance measures and similarity measures of the features. To solve this optimization problem, we use the Nesterov's approach to derive an accelerated gradient algorithm with a fast convergence rate O(1/T2). We further develop a generalization bound for the proposed optimization problem using the Rademacher complexities. Extensive experimental evaluations are conducted on the public LETOR benchmark datasets. The results demonstrate that the proposed method shows: 1) significant ranking performance gain compared to several feature selection baselines for ranking, and 2) very competitive performance compared to several state-of-the-art learning-to-rank algorithms. © 2012 IEEE.


Lei J.F.,Henan University of Science and Technology | Li L.B.,Henan University of Science and Technology | Shen X.H.,Tarim University | Du K.,Henan University of Science and Technology | And 3 more authors.
Langmuir | Year: 2013

Two kinds of ordered ZnO/TiO2 heterostructures were fabricated via a facile approach. The architecture of the TiO2 substrate could be controlled by alternating the filling forms of the template, and the morphology of the secondary ZnO nanostructure could be further tuned by adjusting the parameters of the hydrothermal reaction. Then two different morphologies of ZnO/TiO2 heteroarchitectures with ZnO nanorods and nanoplates growing on TiO2 shells and bowls were successfully achieved, respectively. © 2013 American Chemical Society.


Zheng R.,Massachusetts Institute of Technology | Zheng R.,Beijing Normal University | Gao J.,Massachusetts Institute of Technology | Gao J.,South China Normal University | And 2 more authors.
Nature Communications | Year: 2011

Reversible temperature tuning of electrical and thermal conductivities of materials is of interest for many applications, including seasonal regulation of building temperature, thermal storage and sensors. Here we introduce a general strategy to achieve large contrasts in electrical and thermal conductivities using first-order phase transitions in percolated composite materials. Internal stress generated during a phase transition modulates the electrical and thermal contact resistances, leading to large contrasts in the electrical and thermal conductivities at the phase transition temperature. With graphite/hexadecane suspensions, the electrical conductivity changes 2 orders of magnitude and the thermal conductivity varies up to 3.2 times near 18 °C. The generality of the approach is also demonstrated in other materials such as graphite/water and carbon nanotube/hexadecane suspensions. © 2011 Macmillan Publishers Limited. All rights reserved.


Yu C.,South China Normal University | Zhu H.,Peking University
Differential Geometry and its Application | Year: 2011

In this paper, the geometric meaning of (α,β)-norms is made clear. On this basis, a new class of Finsler metrics called general (α,β)-metrics are introduced, which are defined by a Riemannian metric and a 1-form. These metrics not only generalize (α,β)-metrics naturally, but also include some metrics structured by R. Bryant. The spray coefficients formula of some kinds of general (α,β)-metrics is given and the projective flatness is also discussed. © 2010 Elsevier B.V.


Liu L.-F.,Guangdong University of Technology | Cheng W.,South China Normal University
Biomedical and Environmental Sciences | Year: 2010

Objective: To study the characteristics of a bioflocculant named MBF7 produced by Penicillum strain HHE-P7 and the effects of cultivation conditions on bioflocculant production. Methods: The chemical group in the bioflocculant molecules was shown by Fourier transform infrared (FTIR) spectra, and the average molecular weight of MBF7 was estimated by gel permeation chromatography. The effects of medium components on bioflocculant production and flocculating activity were studied. Results: Phospho-, amino-, hydroxyl, and carboxyl groups were the major fractions of MBF7, and the molecule weight was about 3.0×105 Da. In addition, the carbon and nitrogen sources favorable for the bioflocculant production were glucose and yeast extract respectively. When the initial pH of the medium was adjusted to 5.0, high flocculant efficiency could be achieved. Conclusion: The bioflocculant MBF7 is a new macromolecule with high flocculating efficiency for Kaolin suspension, and could be produced under appropriate culture conditions. Copyright © 2010 by China CDC.


Li J.,Guangdong University of Technology | Li J.,South China Normal University
Match | Year: 2013

A relation is established between the edge Szeged index and the ordinary Szeged index for unicyclic graphs.


Yu R.,South China Normal University | Yu R.,University of Cambridge | Zhao L.,Peking University | Lu L.,Peking University
PLoS ONE | Year: 2011

Cigarette smoking is highly prevalent in the general population but the effects of chronic smoking on brain structures are still unclear. Previous studies have found mixed results regarding regional grey matter abnormalities in smokers. To characterize both grey and white matter changes in heavy male smokers, we investigated 16 heavy smokers and 16 matched healthy controls, using both univariate voxel-based morphometry (VBM) and multivariate pattern classification analysis. Compared with controls, heavy smokers exhibited smaller grey matter volume in cerebellum, as well as larger white matter volume in putamen, anterior and middle cingulate cortex. Further, the spatial patterns of grey matter or white matter both discriminated smokers from controls in these regions as well as in other brain regions. Our findings demonstrated volume abnormalities not only in the grey matter but also in the white matter in heavy male smokers. The multivariate analysis suggests that chronic smoking may be associated with volume alternations in broader brain regions than those identified in VBM analysis. These results may better our understanding of the neurobiological consequence of smoking and inform smoking treatment. © 2011 Yu et al.


Shi Z.,South China Normal University | Shi Z.,Guangdong University of Technology | Li H.,Guangdong Institute of Education | Guo Q.,South China Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

We address surface solitons at the interface between linear media and nonlocal nonlinear media in the presence of a discontinuity in refractive index at the surface of these two materials. We investigated the influence of the degree of nonlocality on the stability, energy flow, and full width at half-maximum of the surface wave solitons. It is shown that surface solitons will be stable only if the degree of nonlocality exceeds a critical value. We find that the refractive index difference can affect the power distribution of the surface solitons in the two media. Also, different boundary values at the interface can lead to different relative peak positions of the surface solitons. However, neither the refractive index nor the boundary conditions can affect the stability of the solitons, for a given degree of nonlocality. © 2011 American Physical Society.


Chen W.,South China Normal University | Lu Z.,University of Texas at Dallas | Wu W.,University of Texas at Dallas
Information Sciences | Year: 2014

Swapped Networks (SNs) are a family of two-level interconnection networks, suitable for constructing large parallel and distributed systems. In this paper, the Minimum Dominating Set (MDS) problem and the Minimum Connected Dominating Set (MCDS) problem in SNs are investigated based on the connectivity rule of SNs. We prove the two problems in SNs are NP-hard, and present two efficient algorithms for building dominating sets and connected dominating sets in SNs. The proposed algorithms use as input a given (connected) dominating set of the factor network, and yield a good approximation of an MDS or MCDS for the SN provided that the input is a good approximation of an MDS or MCDS for the factor network. We also derive several non-trivial bounds on the (connected) domination parameters of SNs. We believe this work is of theoretical interest in graph theory since SNs form a family of graphs. It may also motivate further research on dominating problems in SNs with their potential applications. © 2013 Elsevier Inc. All rights reserved.


Zhang J.,South China Normal University | Li J.,South China Normal University | Li J.,Guangdong University of Technology
Match | Year: 2012

For a simple graph G, the incidence energy IE(G) is defined as the sum of all singular values of its incidence matrix. In this paper, we determine the unique graph with minimal incidence energy among all connected unicyclic graphs and bicyclic graphs of order n, respectively. We also determine the unique graph with maximal incidence energy in the two graph classes, respectively.


Li J.,Guangdong University of Technology | Li J.,South China Normal University | Zhang J.,South China Normal University
Match | Year: 2012

Let G be a simple graph with n vertices. If μ1, μ2,⋯, μn are the Laplacian eigenvalues of G, then the Laplacian Estrada index is defined as LEE(G) = Σ i=1 n eμi. In this paper, the unicyclic graph on n vertices with the maximal Laplacian Estrada index is determined.


Meng H.,Peking University | Luo J.,Peking University | Wang W.,Peking University | Shi Z.,CAS Beijing National Laboratory for Molecular | And 3 more authors.
Advanced Functional Materials | Year: 2013

The relatively high sheet resistance of graphene compared with indium tin oxide (ITO) blocks the applications of graphene as transparent electrodes in organic light-emitting diodes. A novel copper (Cu)/graphene composite electrode is presented and employed as the anode of a top-emission organic light-emitting diode with the structure of Cu/graphene/V2O5/NPB/Alq 3/Alq3: C545T/Bphen: Cs2CO3/Sm/Au. The Cu/graphene composite electrodes are fabricated by growing graphene directly on Cu substrates via the chemical vapor deposition method without any transfer process. The maxima of current efficiency and power efficiency of a typical Cu/graphene composite anode device reach 6.1 cd/A and 7.6 lm/W, respectively, which are markedly higher than those of the control devices with a graphene anode, a Cu anode or an ITO anode. The low sheet resistance of the composite electrode, the high quality of graphene without any transfer process and the avoidance of wave guiding loss in glass or polyethylene terephthalate substrates result in the improvements of light emission efficiencies. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang Y.,South China Normal University | Li B.,South China Normal University | Cui D.,South China Normal University | Xiang X.,South China Normal University | And 2 more authors.
Biosensors and Bioelectronics | Year: 2014

A novel electrode, carbon felt-supported nano-molybdenum carbide (Mo2C)/carbon nanotubes (CNTs) composite, was developed as platinum-free anode of high performance microbial fuel cell (MFC). The Mo2C/CNTs composite was synthesized by using the microwave-assisted method with Mo(CO)6 as a single source precursor and characterized by using X-ray diffraction and transmission electron microscopy. The activity of the composite as anode electrocatalyst of MFC based on Escherichia coli (E. coli) was investigated with cyclic voltammetry, chronoamperometry, and cell discharge test. It is found that the carbon felt electrode with 16.7wt% Mo Mo2C/CNTs composite exhibits a comparable electrocatalytic activity to that with 20wt% platinum as anode electrocatalyst. The superior performance of the developed platinum-free electrode can be ascribed to the bifunctional electrocatalysis of Mo2C/CNTs for the conversion of organic substrates into electricity through bacteria. The composite facilitates the formation of biofilm, which is necessary for the electron transfer via c-type cytochrome and nanowires. On the other hand, the composite exhibits the electrocatalytic activity towards the oxidation of hydrogen, which is the common metabolite of E. coli. © 2013 Elsevier B.V.


Wang J.J.,Massachusetts Institute of Technology | Zheng R.T.,Massachusetts Institute of Technology | Zheng R.T.,Beijing Normal University | Gao J.W.,Massachusetts Institute of Technology | And 2 more authors.
Nano Today | Year: 2012

Nanofluids, liquids containing suspensions of nanoparticles, have been reported by some groups to exhibit substantially higher thermal conductivity than that of their corresponding base fluids that cannot be explained by existing theories. However, the reported high thermal conductivity sometimes cannot be reproduced by others. Potential mechanisms leading to this enhancement are still under scrutiny. In this paper, we first take a critical review of heat conduction mechanisms proposed in literature, and then summarize our work. Our experimental studies demonstrate that nanoparticle clustering is the key contributor to the thermal conductivity enhancement. Guided by this insight, we use graphite flakes as additives and develop a method to prepare stable graphite suspensions with large thermal conductivity enhancement in water and oil. We also observe thermal percolation phenomenon and explained the phenomenon based on combined optical and AC impedance spectroscopy studies. We demonstrate temperature regulation of electrical and thermal properties of graphite suspensions through solid-liquid phase change, which may potentially be useful in energy systems in the future. © 2012 Elsevier Ltd.


Tao P.J.,Guangdong University of Technology | Yang Y.Z.,Guangdong University of Technology | Ru Q.,South China Normal University
Journal of Alloys and Compounds | Year: 2010

A Zr 55Cu 30Ni 5Al 10 bulk metallic glass (BMG) with a dimension of 1 mm × 10 mm × 70 mm was prepared by using copper-mold suction casting and the effect of rotational sliding velocity (RSV) on the surface dry friction and wear behavior was studied at room temperature. The results showed that the grinding traces of the BMG specimens remain an amorphous structure after friction and wear behavior tests under a load of 5 N with a rotational velocity range of 200-1400 r/min through 8 min. The friction coefficients mainly locate between 0.15 and 0.35. With increasing RSVs, both average friction coefficient and wear weight loss present an upward trend. Obvious molten characteristics can be observed in all grinding traces. At lower RSVs, the wear mechanism tends to a combined action of continuous wear and surface flow, while at higher RSVs, the wear inclines to surface flow. In addition, slight oxidation and adhesion wear accompany during all friction and wear behavior tests. © 2009 Elsevier B.V. All rights reserved.


SHENZHEN, China, Nov 9, 2016 /PRNewswire/ -- On November 5, 2016, the 10th China International Financial Expo 'China Educational Financial Summit Forum' was held in Shenzhen. Under the guidance of the Shenzhen Municipal government, various major financial associations and Peking University Shenzhen Institute launched and promoted major financial innovations and established the Financial Innovation Center of Peking University Shenzhen Institute (FICPUSI). It covers Shenzhen banking, security, insurance, fund, trust, and investment organizations. The FICPUSI planned to establish a RMB100 million special educational public fund, and a RMB2 billion educational investment fund. The FICPUSI is also planning to develop a 'Superior Education Plan' which will cover national quality education and advanced educational technology, advanced international education, and educational large data application. This 'Superior Education Plan' aims to promote national quality educational courses development with a global horizon, international student contests, international teacher and principal training, academic IT application, and the establishment of elite independent schools, and planning future elite educational companies and schools. Moreover, the event also marks the launch of special educational financial products design and upgrading of schools and educational enterprises. The Plan helps to accelerate the funding and acquiring of special excellent educational enterprises and schools, push them to enter the capital market, and foster the sustainable development of educational innovation. At the 2016 China Educational Financial Summit Forum, Financial Innovation Center of Peking University Shenzhen Institute signed a MOU with Ivy Elite Education Association and the League of 100 Quality School in China, to develop the "Superior Education Plan", and establish the special educational public fund, for conducting China-US educational cooperations on curricula, school improvement projects, principals and teachers' training, and standard-based school accreditation. The 'China Educational Financial Summit Forum' was directed by China Academic Degrees & Graduate Education Development Center (CADGEDC) and the Shenzhen municipal government and was co-sponsored by Peking University Shenzhen Institute, Shenzhen Banking Association, Shenzhen Securities Association, Shenzhen Insurance Association, South China Normal University, Association of Principals of Guangdong Province, Ivy Elite Education Association, and Shenzhen Innovation Corporate Social Responsibility Development Center. It was supported by China Construction Bank (Shenzhen Branch), Bank of China (Shenzhen Branch), Ping An Insurance Group China, Ltd., Essence Securities, and Chang'An Trust. The forum focused on the formulation of 'The Education Act'. With the enforcement of 'Private Education Promotion Law', financial organizations will now cooperate with national educational sectors, pushing forward the acquisition and integration of schools. They intend to promote the development of special educational investment fund, educational IPO, school capital securitization, educational trust, fund, insurance, credit, overseas educational finance, and other blue ocean financial businesses. The forum also made analyses of issues on how to promote the integration, financialization, and internationalization of China independent education, it encouraged the mechanism of survival of the fittest in the capital involvement in education. It planned to make integration of more excellent educational enterprises and schools in China. Mr. Zhao Yu, Assistant Director of CADGEDC, one of the guiding institutes for Superior Education Plan, said The Center will provide great support to the joint efforts between China financial and educational organizations in order to implement national educational reform, and it will encourage more business schools in Chinese universities to design financial products and investment modes with financial investment organizations. Mr. Xiao Zhijia, Vice Director of Financial Affairs for the Shenzhen municipal government and one of the guiding institutes for Superior Education Plan, said this education financial conference is a grand meeting to reflect the promotion of educational innovation through national financial development, and the innovative cooperation between capital and educational industries. It is an opportunity for more excellent educational enterprises and schools to achieve integration and capitalization, and step into multi-capital market in quick pace, which is significant for both practice and exploration. Mr. Tan Wenchang, President of Peking University Shenzhen Institute and one of the guiding institutes for Superior Education Plan introduced that it is necessary to take advantage of the tremendous influence and reputation of Peking University at home and abroad. Peking University aims to work with government sectors to advocate national financial investment organizations to carry out reform and innovation in the educational industry. In the meantime, The Plan will allocate Peking University special educational investment funds in financial investment organizations in Shenzhen, Guangzhou, Shanghai, Beijing, and Chengdu to foster industrial chain cooperation and M&A of excellent schools and educational enterprises nationwide. It is targeted for sustainable promotion of the major financial innovation of national financial investment organizations. Ms Emily Hu, Chief Director of Ivy Elite Education Association China Affairs Center, expressed that a growing involvement of China financial investment capital in the incubation of financial investment and educational financial products in excellent secondary schools and famous educational enterprises offers great impetus to the cooperation between quality American educational resources and Chinese educational resources and channels. These resources include excellent American principals and teachers, professional resources, curriculum and student projects, information technology, and educational assessment standards and certification. Utilizing these resources will improve the efficiency of current conventional Chinese international educational cooperation. Professor Wang Hong, Director of Overseas Teacher Training Base of the Ministry of Education, and Professor of the School of Professional Development and Research on Primary and Secondary Education, believes that there are many benefits to encouraging renowned Chinese financial organizations like banks, funds, trusts, and insurance companies to participate in Chinese educational innovation and explore international educational cooperation. This will not only establish special principal and teacher training bases in international cooperation fields in China, but sets up China overseas educational training bases for Chinese school investors, principals, teachers, and educational enterprises in America and Europe, including online educational training bases. All of this can bring reduction of expenses for Chinese principal and teacher training and helps to lead a professional upgrade of educational staff. To view the original version on PR Newswire, visit:http://www.prnewswire.com/news-releases/the-initial-joint-promotion-of-educational-innovation-between-chinese-financial-and-educational-organizations-300359203.html


Yang T.,City University of Hong Kong | Yang T.,Shanghai JiaoTong University | Yu H.,South China Normal University
Archive for Rational Mechanics and Analysis | Year: 2016

We analyze the spectrum structure of some kinetic equations qualitatively by using semigroup theory and linear operator perturbation theory. The models include the classical Boltzmann equation for hard potentials with or without angular cutoff and the Landau equation with (Formula presented.). As an application, we show that the solutions to these two fundamental equations are asymptotically equivalent (mod time decay rate (Formula presented.)) as (Formula presented.) to that of the compressible Navier–Stokes equations for initial data around an equilibrium state. © 2016 Springer-Verlag Berlin Heidelberg


Li G.-B.,South China Normal University | Fang H.-C.,South China Normal University | Cai Y.-P.,South China Normal University | Zhou Z.-Y.,South China Normal University | And 2 more authors.
Inorganic Chemistry | Year: 2010

A novel Zn-Ni heterotrinuclear Schiff base compound bearing acacen 2- moieties was constructed through the selective assembly of a chemosensor Schiff base zinc compound with a Ni2+ ion. Its crystal structure not only clearly explains the binding mode between the chemosensor molecule and the detected metal ion but also represents the first trinuclear complex based on a symmetric acacen2- base Schiff base. © 2010 American Chemical Society.


Hong X.,South China Normal University | He S.,South China Normal University | He S.,KTH Royal Institute of Technology
Optics Express | Year: 2015

An optical phase noise suppression algorithm, LI-SCPEC, based on phase linear interpolation and sub-symbol processing is proposed for CO-OFDM system. By increasing the temporal resolution of carrier phase tracking through dividing one symbol into several sub-blocks, i.e., sub-symbols, inter-carrier-interference (ICI) mitigation is achieved in the proposed algorithm. Linear interpolation is employed to obtain a reliable temporal reference for sub-symbol phase estimation. The new algorithm, with only a few number of sub-symbols (NB = 4), can provide a considerably larger laser linewidth tolerance than several other ICI mitigation algorithms as demonstrated by Monte-Carlo simulations. Numerical analysis verifies that the best performance is achieved with an optimal and moderate number of sub-symbols. Complexity analysis shows that the required number of complex-valued multiplications is independent of the number of sub-symbols used in the proposed algorithm. ©2015 Optical Society of America.


Hong X.,South China Normal University | He S.,South China Normal University | He S.,KTH Royal Institute of Technology
Optics Express | Year: 2015

A low-complexity optical phase noise suppression approach based on recursive principal components elimination, R-PCE, is proposed and theoretically derived for CO-OFDM systems. Through frequency domain principal components estimation and elimination, signal distortion caused by optical phase noise is mitigated by R-PCE. Since matrix inversion and domain transformation are completely avoided, compared with the case of the orthogonal basis expansion algorithm (L = 3) that offers a similar laser linewidth tolerance, the computational complexities of multiple principal components estimation are drastically reduced in the RPCE by factors of about 7 and 5 for q = 3 and 4, respectively. The feasibility of optical phase noise suppression with the R-PCE and its decision-aided version (DA-R-PCE) in the QPSK/16QAM CO-OFDM system are demonstrated by Monte-Carlo simulations, which verify that RPCE with only a few number of principal components q ( = 3) provides a significantly larger laser linewidth tolerance than conventional algorithms, including the common phase error compensation algorithm and linear interpolation algorithm. Numerical results show that the optimal performance of R-PCE and DA-R-PCE can be achieved with a moderate q, which is beneficial for low-complexity hardware implementation. © 2015 Optical Society of America.


Li C.,Duke University | Zheng X.,Anhui University of Science and Technology | Cohen A.J.,University of Cambridge | Mori-Sanchez P.,Autonomous University of Madrid | And 2 more authors.
Physical Review Letters | Year: 2015

Delocalization error is one of the most fundamental and dominant errors that plagues presently used density functional approximations. It is responsible for a large class of problems in the density functional theory calculations. For an effective and universal alleviation of the delocalization error, we develop a local scaling correction scheme by imposing the Perdew-Parr-Levy- Balduz linearity condition to local regions of a system. Our novel scheme is applicable to various mainstream density functional approximations. It substantially reduces the delocalization error, as exemplified by the significantly improved description of dissociating molecules, transition-state species, and charge-transfer systems. The usefulness of our novel scheme affirms that the explicit treatment of fractional electron distributions is essentially important for reducing the intrinsic delocalization error associated with approximate density functionals. © 2015 American Physical Society.


Yu R.,Medical Research Council | Yu R.,South China Normal University | Calder A.J.,Medical Research Council | Mobbs D.,Medical Research Council | Mobbs D.,Columbia University
Human Brain Mapping | Year: 2014

Advantageous inequality (AI) aversion, or paying at a personal cost to achieve equal reward distribution, represents a unique feature of human behavior. Here, we show that individuals have strong preferences for fairness in both disadvantageous (DI) and advantageous inequality (AI) situations, such that they alter others' payoff at a personal financial cost. At the neural level, we found that both types of inequality activated the putamen, orbitofrontal cortex, and insula, regions implicated in motivation. Individual difference analyses found that those who spent more money to increase others' payoff had stronger activity in putamen when they encountered AI and less functional connectivity between putamen and both orbitofrontal cortex and anterior insula. Conversely, those who spent more money to reduce others' payoff had stronger activity in amygdala in response to DI and less functional connectivity between amygdala and ventral anterior cingulate cortex. These dissociations suggest that both types of inequality are processed by similar brain areas, yet modulated by different neural pathways. © 2013 Wiley Periodicals, Inc.


Zhu H.,South China Normal University | Fan Y.,Guangzhou Rehabilitation and Research Center for Children with | Guo H.,South China Normal University | Huang D.,Guangzhou Rehabilitation and Research Center for Children with | And 2 more authors.
Biomedical Optics Express | Year: 2014

Autism spectrum disorder (ASD) is a neuro-developmental disorder, which has been associated with atypical neural synchronization. In this study, functional near infrared spectroscopy (fNIRS) was used to study the differences in functional connectivity in bilateral inferior frontal cortices (IFC) and bilateral temporal cortices (TC) between ASD and typically developing (TD) children between 8 and 11 years of age. As the first report of fNIRS study on the resting state functional connectivity (RSFC) in children with ASD, ten children with ASD and ten TD children were recruited in this study for 8 minute resting state measurement. Compared to TD children, children with ASD showed reduced interhemispheric connectivity in TC. Children with ASD also showed significantly lower local connectivity in bilateral temporal cortices. In contrast to TD children, children with ASD did not show typical patterns of symmetry in functional connectivity in temporal cortex. These results support the feasibility of using the fNIRS method to assess atypical functional connectivity of cortical responses of ASD and its potential application in diagnosis. © 2014 Optical Society of America.


Liu Y.,Guangdong University of Finance | Du Y.,South China Normal University | Lin C.,South China Normal University
Journal of Mathematical Fluid Mechanics | Year: 2010

The Forchheimer equations for non-slow flow in a saturated porous medium are studied. We prove the convergence results for both the first and the second Forchheimer coefficients. © 2009 Birkhäuser Verlag, Basel.


Liu G.,Hebei University of Science and Technology | Hao N.,CAS Institute of Physics | Hao N.,Purdue University | Zhu S.-L.,South China Normal University | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We propose a scenario to create a topological superfluid in a periodically driven two-dimensional square optical lattice. We study the phase diagram of a spin-orbit coupled s-wave pairing superfluid in a periodically driven two-dimensional square optical lattice. We find that a phase transition from a trivial superfluid to a topological superfluid occurs when the potentials of the optical lattices are periodically changed. The topological phase is called the Floquet topological superfluid and can host Majorana fermions. © 2012 American Physical Society.


Liu G.,CAS Institute of Physics | Zhu S.-L.,South China Normal University | Jiang S.,CAS Institute of Physics | Sun F.,CAS Institute of Physics | Liu W.M.,CAS Institute of Physics
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2010

We propose a model which includes a nearest-neighbor intrinsic spin-orbit coupling and a trimerized Hamiltonian in the kagome lattice and promises to host the transition from the quantum spin Hall insulator to the normal insulator. In addition, we design an experimental scheme to simulate and detect this transition in the ultracold atom system. The lattice intrinsic spin-orbit coupling is generated via the laser-induced-gauge-field method. Furthermore, we establish the connection between the spin Chern number and the spin-atomic density which enables us to detect the quantum spin Hall insulator directly by the standard density-profile technique used in atomic systems. © 2010 The American Physical Society.


Wang B.,South China Normal University | Zhan Q.,South China Normal University | Zhao Y.,South China Normal University | Wu R.,South China Normal University | And 3 more authors.
Optics Express | Year: 2016

Further development of multiphoton microscopic imaging is confronted with a number of limitations, including high-cost, high complexity and relatively low spatial resolution due to the long excitation wavelength. To overcome these problems, for the first time, we propose visible-to-visible four-photon ultrahigh resolution microscopic imaging by using a common cost-effective 730-nm laser diode to excite the prepared Nd3+-sensitized upconversion nanoparticles (Nd3+-UCNPs). An ordinary multiphoton scanning microscope system was built using a visible CW diode laser and the lateral imaging resolution as high as 161-nm was achieved via the four-photon upconversion process. The demonstrated large saturation excitation power for Nd3+-UCNPs would be more practical and facilitate the four-photon imaging in the application. A sample with fine structure was imaged to demonstrate the advantages of visible-to-visible four-photon ultrahigh resolution microscopic imaging with 730-nm diode laser excited nanocrystals. Combining the uniqueness of UCNPs, the proposed visible-to-visible four-photon imaging would be highly promising and attractive in the field of multiphoton imaging. © 2015 Optical Society of America.


Guo S.,Hunan Normal University | Kendrick K.M.,University of Electronic Science and Technology of China | Yu R.,South China Normal University | Wang H.-L.S.,National Taiwan University | And 2 more authors.
Human Brain Mapping | Year: 2014

There is still no clear consensus as to which of the many functional and structural changes in the brain in schizophrenia are of most importance, although the main focus to date has been on those in the frontal and cingulate cortices. In the present study, we have used a novel holistic approach to identify brain-wide functional connectivity changes in medicated schizophrenia patients, and functional connectivity changes were analyzed using resting-state fMRI data from 69 medicated schizophrenia patients and 62 healthy controls. As far as we are aware, this is the largest population reported in the literature for a resting-state study. Voxel-based morphometry was also used to investigate gray and white matter volume changes. Changes were correlated with illness duration/symptom severity and a support vector machine analysis assessed predictive validity. A network involving the inferior parietal lobule, superior parietal gyrus, precuneus, superior marginal, and angular gyri was by far the most affected (68% predictive validity compared with 82% using all connections) and different components correlated with illness duration and positive and negative symptom severity. Smaller changes occurred in emotional memory and sensory and motor processing networks along with weakened interhemispheric connections. Our findings identify the key functional circuitry altered in schizophrenia involving the default network midline cortical system and the cortical mirror neuron system, both playing important roles in sensory and cognitive processing and particularly self-processing, all of which are affected in this disorder. Interestingly, the functional connectivity changes with the strongest links to schizophrenia involved parietal rather than frontal regions. Hum Brain Mapp 35:123-139, 2014. © 2012 Wiley Periodicals, Inc.


Sun Z.,Hunan University | Zeng J.,Dongguan University of Technology | Li D.,South China Normal University
BIT Numerical Mathematics | Year: 2010

Semismooth Newton method is an effective method for solving a nonsmooth equation, which arises from a reformulation of the complementarity problem. Under appropriate conditions, we verify the monotone convergence of the method. We also present semismooth Newton Schwarz iterative methods for the nonsmooth equation. Under suitable conditions, the methods exhibit monotone and superlinear convergence properties. © 2010 Springer Science + Business Media B.V.


Li X.,Cincinnati Childrens Hospital Medical Center | Li X.,South China Normal University | Erden O.,Cincinnati Childrens Hospital Medical Center | Li L.,Cincinnati Childrens Hospital Medical Center | And 3 more authors.
Antioxidants and Redox Signaling | Year: 2014

Aims: A component of the base excision repair pathway, poly(ADP-ribose) polymerase-1 (PARP1) functions in multiple cellular processes, including DNA repair and programmed cell death. We previously showed that Salidroside, a phenylpropanoid glycoside isolated from medicinal plants, prevented the loss of hematopoietic stem cells (HSCs) in native mice and rescued HSCs repopulating in transplanted recipients under oxidative stress. The aim of this study was to investigate the mechanism by which PARP1 activation by Salidroside maintains HSCs under oxidative stress. Results: We found that although there were no spontaneous defects in hematopoiesis in Parp1-/- mice, oxidative stress compromised the repopulating capacity of Parp1-/- HSCs in transplanted recipient mice. A biochemical study using truncated proteins lacking the defined functional domains of PARP1 showed that the tryptophan-glycine-arginine-rich (WGR) domain of PARP1 was critical for Salidroside binding and subsequent PARP1 activation under oxidative stress. Functionally, complementation of Parp1-/- HSCs with full-length PARP1WT, but not the PARP1R591K mutant in WGR domain restored Salidroside-stimulated PARP1 activation in vitro. Mechanistically, activated PARP1 by Salidroside enhanced the repopulating capacity of the stressed HSCs by accelerating oxidative DNA damage repair. Innovations and Conclusion: Our findings reveal the action of mechanism for Salidroside in PARP1 stimulation and a novel role of PARP1 activation in maintaining HSC function under oxidative stress. Antioxid. Redox Signal. 20, 1853-1865. © Copyright 2014, Mary Ann Liebert, Inc. 2014.


Li Y.,University for Business Studies | Liu Y.,Guangdong University of Finance | Lin C.,South China Normal University
Nonlinear Analysis: Real World Applications | Year: 2010

In this paper, we determine the lower bound for the blow-up time of solution to equations of the form ut=div(ρ(|∇u|2)gradu)+f(u) if the solution blows up. The conditions which ensure that blow-up does not occur are also presented. © 2009 Elsevier Ltd. All rights reserved.


Chen Y.,South China Normal University | Dai L.,Mathematics Teaching and Research Group | Lu Z.,Xiangtan University
Advances in Applied Mathematics and Mechanics | Year: 2010

We investigate the superconvergence properties of the constrained quadratic elliptic optimal control problem which is solved by using rectangular mixed finite element methods. We use the lowest order Raviart-Thomas mixed finite element spaces to approximate the state and co-state variables and use piecewise constant functions to approximate the control variable. We obtain the superconvergence of O(h 1+s) (0


News Article | October 10, 2016
Site: www.greencarcongress.com

« Green Commuter receives $750K to support electric car sharing service in Chattanooga | Main | China researchers devise process to convert biomass to gasoline via one-step DME synthesis: DTG » Researchers at South China Normal University in Guangzhou have developed a novel composite of sulfur loaded in micropore-rich carbon aerogel (CA-S) for use as a cathode in Li-sulfur batteries. Compared to sulfur loaded in a common carbon material, acetylene black (AB-S), the CA-S exhibited significantly improved cyclic stability and rate capability. The CA is micropore-rich with micropore volume over 66% of total pore volume. In a paper in the Journal of Power Sources, and team attributed the improved performance of CA-S to the confinement of the micropores in CA to small sulfur allotropes and corresponding lithium sulfides. Because of the abundance of sulfur on the Earth, the high theoretical specific capacity (1675 mAh g-1) of sulfur cathode, and the high theoretical gravimetric as well as volumetric energy density (2567 Wh kg-1 and 2800 Wh L-1, respectively) of the battery, lithium-sulfur battery is attracting more and more attention. However, lithium-sulfur battery exhibits poor rate capability, inadequate cyclic stability and short calendar life, due to the insulating nature of sulfur and lithium sulfide, the high solubility of the intermediate lithium polysulfides (Li S ) in organic electrolyte, and the significant volume change during charge/ discharge process. These issues limit the practical application of lithium-sulfur battery. Many efforts have been made to improve the performances of lithium-sulfur batteries. Among these efforts, introducing porous carbon materials into sulfur cathode has been found to be an effective strategy. … It has been found that the size of pores in carbon materials plays an important role in the cyclic stability improvement of sulfur. … Compared with other carbon materials, carbon aerogel synthesized by using special method possesses large specific surface area as well as abundant pores, and has been applied as support of sulfur cathode of lithium-sulfur battery However, the resulting carbon aerogels, which were obtained from the precursors synthesized with high catalyst concentrations and through carbonization under lower temperature, were not characteristic of microporous structure. In this work, we proposed a novel composite, sulfur loaded in micropore-rich carbon aerogel, as the cathode of lithium-sulfur battery. Carbon aerogel was synthesized through phenol-formaldehyde reaction with a low catalyst concentration and carbonization under high temperature, which favors the formation of micropores. The resulting carbon aerogel possesses microporous structure, and the corresponding sulfur composite exhibits improved cyclic stability and rate capability. To create the carbon and sulfur composite (CA-S), the team loaded sulfur in the resulting CA via chemical deposition and heat treatment. During the formation of CA-S, the heat treatment allows S to decompose to S allotropes, among which smaller chain-like S migrate into the micropores in the aerogel. These micropores are capable of immobilizing small S allotropes and prevent them from transforming back to electrolyte-soluble Li S , leading to the improved cyclic stability, the team concluded. Due to the highly electronic conductivity of CA, the resulting CA-S also exhibits excellent rate capability.


Qiu Y.,Hong Kong University of Science and Technology | Yan K.,Hong Kong University of Science and Technology | Yang S.,Hong Kong University of Science and Technology | Jin L.,South China Normal University | And 2 more authors.
ACS Nano | Year: 2010

This paper embarks upon three levels of undertaking ranging from nanomaterials synthesis to assembly and functionalization. First, we have prepared size-tunable anatase TiO2 nanospindles via a hydrothermal process by using tubular titanates as self-sacrificing precursors. Second, we have densely dispersed the TiO2 nanospindles onto functional graphene oxides (GO) via a spontaneous self-assembly process. After annealing of the TiO2/GO hybrid nanocomposite in an NH3 gas flow, the TiO2 surface was effectively nitridated and the GO was reduced to graphene sheets (GS) in order to further fortify the electronic functionality of the nanocomposite. Third, the anatase@oxynitride/titanium nitride-GS (TiO 2@TiOxNy/TiN-GS) hybrid nanocomposite was studied as an anode material for lithium-ion batteries (LIBs), showing excellent rate capability and cycling performance compared to the pure TiO2 nanospindles. Our systematic studies have revealed that the TiO 2@TiOxNy/TiN-GS nanocomposites with graphene nanosheets covered with the TiO2@TiOxNy/TiN nanospindles on both sides provide a promising solution to the problems of poor electron transport and severe aggregation of TiO2 nanoparticles by enhancing both electron transport through the conductive matrix and Li-ion accessibility to the active material from the liquid electrolyte. More generally, the size-tunable TiO2 nanospindles with their unique (101) outer surface planes provide an archetype for the in depth investigation of their surface-specific and size-dependent physicochemical properties. © 2010 American Chemical Society.


Liu W.,South China Normal University | Fan F.,South China Normal University | Liu J.,University of Pennsylvania
Journal of Traumatic Stress | Year: 2013

This study sought to expand the literature on bereavement and response to natural disasters by reporting the prevalence, severity, and correlates of depressive symptoms among bereaved and nonbereaved parents of the 2008 Wenchuan Earthquake in China. Bereaved (n = 155) and nonbereaved (n = 35) parents from the Xiang'e township in China were interviewed at 18 months (Wave 1) and 24 months (Wave 2) following the earthquake. From Wave 1 to Wave 2, rates of probable depression fell for both bereaved (65.8% to 44.5%) and nonbereaved parents (34.3% to 20.0%). The depression index of both groups also decreased, but only significantly among bereaved parents. Of bereaved parents, those with fewer years of education had more severe symptoms at both waves. Depressive symptom severity of bereaved mothers improved over time, but that of bereaved fathers remained unchanged. Not becoming pregnant again after the earthquake was significantly linked to worse depressive symptoms in both waves, but this was not significant when age was added to the model. Bereaved parents may need more postearthquake supportive services, with fathers, individuals with fewer years of education, and parents who are not able to become pregnant again after the earthquake being particularly vulnerable. © 2013 International Society for Traumatic Stress Studies.


Zhou J.,Nanjing University | Wang J.,Nanjing University | Shen B.,Nanjing University | Chen L.,Nanjing University | And 5 more authors.
FEBS Journal | Year: 2014

The bacterial clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system is a versatile RNA-guided mammalian genome modification system. One-step generation of mouse genome targeting has been achieved by co-microinjection of one-cell stage embryos with Cas9 mRNA and small/single guide (sg)RNA. Many studies have focused on enhancing the efficiency of this system. In the present study, we report that simultaneous use of dual sgRNAs to target an individual gene significantly improved the Cas9-mediated genome targeting with a bi-allelic modification efficiency of up to 78%. We further observed that the target gene modifications were characterized by efficient germline transmission and site-dependent off-target effects, and also that the apolipoprotein E gene knockout-mediated defects in blood biochemical parameters were recapitulated by CRISPR/Cas9-mediated heritable gene modification. Our results provide a dual sgRNAs strategy to facilitate CRISPR/Cas9-mediated mouse genome targeting. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) endonuclease, also known as an RNA-guided endonuclease (RGEN), is increasingly being used for eukaryote genome targeting; however, its efficiency, specificity and versatility needs to be optimized. In this issue, Zhou et al. report an improved method for CRISPR/Cas9-mediated gene targeting, and show that the simultaneous use of dual sgRNAs to target an individual mouse gene is a more efficient and specific method than using just a single sgRNA. This new dual sgRNAs strategy will facilitate CRISPR/Cas9-mediated mammalian genome targeting. © 2014 FEBS.


Wang Y.,South China Normal University | Li B.,South China Normal University | Zeng L.,South China Normal University | Cui D.,South China Normal University | And 3 more authors.
Biosensors and Bioelectronics | Year: 2013

A composite, polyaniline (PANI)/mesoporous tungsten trioxide (m-WO3), was developed as a platinum-free and biocompatible anodic electrocatalyst of microbial fuel cells (MFCs). The m-WO3 was synthesized by a replicating route and PANI was loaded on the m-WO3 through the chemical oxidation of aniline. The composite was characterized by using X-ray diffraction, Fourier transform infrared spectrum, field emission scanning electron microscopy, and transmission electron microscopy. The activity of the composite as the anode electrocatalyst of MFC based on Escherichia coli (E. coli) was investigated with cyclic voltammetry, chronoamperometry, and cell discharge test. It is found that the composite exhibits a unique electrocatalytic activity. The maximum power density is 0.98Wm-2 for MFC using the composite electrocatalyst, while only 0.76Wm-2 and 0.48Wm-2 for the MFC using individual m-WO3 and PANI electrocatalyst, respectively. The improved electrocatalytic activity of the composite can be ascribed to the combination of m-WO3 and PANI. The m-WO3 has good biocompatibility and PANI has good electrical conductivity. Most importantly, the combination of m-WO3 and PANI improves the electrochemical activity of PANI for proton insertion and de-insertion. © 2012 Elsevier B.V..


Zhang J.-Q.,CAS Wuhan Institute of Physics and Mathematics | Li Y.,Beijing Computational Science Research Center | Feng M.,CAS Wuhan Institute of Physics and Mathematics | Xu Y.,South China Normal University | Xu Y.,Guangzhou University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We propose a potentially practical scheme to precisely measure the charge number of small charged objects by using optomechanically induced transparency (OMIT) in optomechanical systems. In contrast to conventional measurements based on noise backaction on optomechanical systems, our scheme presents an alternative way to detect the charge number exactly, by monitoring small deformation of the mechanical resonator sensitive to the charge number of nearby charged object. The relationship between the charge number and the OMIT window width is investigated and the feasibility of the scheme is justified by numerical simulation with currently available experimental values. © 2012 American Physical Society.


Daochun S.,South China Normal University | Zongsheng G.,Beihang University
Acta Mathematica Scientia | Year: 2010

In this article, we first investigate the operational properties of algebroid functions. Then we prove two uniqueness theorems for algebroid functions. © 2010 Wuhan Institute of Physics and Mathematics.


Yuan P.,South China Normal University | Ding C.,Hong Kong University of Science and Technology
Finite Fields and their Applications | Year: 2014

Permutation polynomials are an interesting subject of mathematics and have applications in other areas of mathematics and engineering. In this paper, we develop general theorems on permutation polynomials over finite fields. As a demonstration of the theorems, we present a number of classes of explicit permutation polynomials on Fq. © 2014 Elsevier Inc.


Yuan P.,South China Normal University | Ding C.,Hong Kong University of Science and Technology
Finite Fields and their Applications | Year: 2014

Let q be a power of 2, k a positive integer and let Sk=x+x q+⋯+xqk-1ε Fq[x]. In this paper, we present a number of classes of explicit permutation polynomials on Fq3 k, which are of the form L(x)+ S2k a + S2k b, where ε{1,qk,q2k}, bε{1,qk,q2k}, and L(x) are linearized polynomials. We also point out an application of these permutation polynomials in combinatorics, cryptography and sequences. © 2014 Elsevier Inc.


Hu L.-Y.,Jiangxi Normal University | Hu L.-Y.,Beijing Computational Science Research Center | Zhang Z.-M.,South China Normal University
Journal of the Optical Society of America B: Optical Physics | Year: 2013

We investigate the statistical properties and inseparability of the field states generated by any order nonlocal coherent photon addition (CPA) to the two-mode squeezed vacuum (TMSV). It is shown that the normalization factor of the CPA-TMSV is a Legendre polynomial, a compact expression. The statistical properties are discussed according to the analytical expressions of cross-correlation function, antibunching effect, and the negativity of its Wigner function. The inseparability is presented by using Shchukin-Vogel criteria and the Einstein-Podolsky- Rosen correlation. It is found that the symmetrical CPA-TMSV may possess stronger correlation than the singlemode photon-addition case. The lower bound of entanglement of the CPA-TMSV is considered, which indicates the logarithmic negativity is invalid for verifying the entanglement when the squeezing parameter is less than a threshold value, a period function of π/2. In addition, quantum teleportation is examined, which shows that asymmetric photon-added TMSV may be more useful for teleportation than the symmetric case. © 2013 Optical Society of America.


Qiu C.,South China Normal University | Yuan Z.,South China Normal University | Liu L.,South China Normal University | Ye N.,EVE Energy Co. | Liu J.,EVE Energy Co.
Journal of Solid State Electrochemistry | Year: 2013

A sol-gel method using Ti(OC4H9)4, LiCH3COO·2H2O, and La(NO3) 3·6H2O as starting materials and ethyl acetoacetate as chelating agent to prepare pure and lanthanum (La)-doped Li 4Ti5O12 is reported. The structure and morphology of the active materials characterized by powder X-ray diffraction and scanning electron microscopy analysis indicate that doping with a certain amount of La3+ does not affect the structure of Li4Ti 5O12, but can restrain the agglomeration of the particles during heat treatment. The electrochemical properties measured by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic charge-discharge cycling tests show that La-doped Li4Ti 5O12 presents a much improved electrochemical performance due to a decrease in charge transfer resistance. At current densities of 1 and 5 C, the La-doped Li4Ti5O12 exhibits excellent reversible capacities of 156.16 and 150.79 mAh g-1, respectively. The excellent rate capability and good cycling performance make La-doped Li 4Ti5O12 a promising anode material for lithium-ion batteries in energy storage systems. © 2012 Springer-Verlag Berlin Heidelberg.


Liu L.,South China Normal University | Yuan Z.,South China Normal University | Qiu C.,South China Normal University | Liu J.,EVE Energy Co.
Solid State Ionics | Year: 2013

Micro-spherical FeS2/CNT powder was synthesized through one-step hydrothermal method for the first time. Carbon nanotube (CNT) had a great influence on the structure, morphology and electrochemical performance of FeS2/CNT powder. X-ray diffraction (XRD) patterns have demonstrated that the existence of CNT can restrain the growth of marcasite during hydrothermal process. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) test have shown that CNT help to form monodisperse micro-sphere particles. Comparing with untreated FeS2, FeS 2/CNT electrode exhibits superior rate and cycling performance. The FeS2/CNT powders can sustain 491 and 370 mAh g- 1, much higher than FeS2 prepared without CNT (265 and 74 mAh g - 1) after 50 cycles at 0.1 and 1 C (1 C = 890 mA g- 1). © Copyright 2013 Published by Elsevier B.V. All rights reserved.


Qin R.,Tianjin Normal University | Qin R.,South China Normal University | Jiang W.,Tianjin Normal University | Liu D.,Tianjin Normal University
Chemosphere | Year: 2013

A 50. μM aluminum (Al) could induce nucleolar materials containing the argyrophilic proteins scattered in the nuclei and extruded from the nuclei into the cytoplasm in the root tip cells of Allium cepa. Unfortunately, what kinds of nucleolar proteins are affected has not been reported till now. In order to go deeper into the understanding of the cytological effects of Al on nucleolus and nucleolar proteins, alterations in the cellular localization and expression of three major nucleolar proteins: nucleophosmin, nucleolin, and fibrillarin were further examined under the treatment with Al in the root tip cells of A. cepa in the present study. Cytological effects of Al on nucleolus were observed by silver-staining method and three major nucleolar proteins: nucleophosmin, nucleolin, and fibrillarin were examined by western blotting. The results indicated that in the presence of 50. μM Al for 48. h the nucleolar proteins were translocated from nucleolus to nucleoplasm and cytoplasm. Western blotting data demonstrated the relatively higher expression of the three major nucleolar proteins when compared with control. Evidence from the present investigation indicated that Al had toxic effects on Ag-NOR proteins, nucleophosmin and nucleolin, and other kinds of nucleolar proteins, fibrillarin. © 2012 Elsevier Ltd.


Yan Zhang Y.,South China Normal University | Yan Zhang Y.,Hong Kong University of Science and Technology | An Yin Y.,South China Normal University
Applied Physics Letters | Year: 2011

The characteristics of the nitride-based blue light-emitting diode (LED) with an AlGaN/GaN superlattice (SL) electron-blocking layer (EBL) of gradual Al mole fraction are analyzed numerically and experimentally. The emission spectra, carrier concentrations in the quantum wells, energy band diagrams, electrostatic fields, and internal quantum efficiency are investigated. The results indicate that the LED with an AlGaN/GaN SL EBL of gradual Al mole fraction has a better hole injection efficiency, lower electron leakage, and smaller electrostatic fields in its active region over the LED with a conventional rectangular AlGaN EBL or with a normal AlGaN/GaN SL EBL. The results also show that the efficiency droop is markedly improved when the SL EBL of gradual Al mole fraction is used. © 2011 American Institute of Physics.


Zhang Y.-Y.,Hong Kong University of Science and Technology | Yao G.-R.,South China Normal University
Journal of Applied Physics | Year: 2011

In this study, the characteristics of the nitride-based blue light-emitting diode (LED) with AlGaN barriers are analyzed numerically and experimentally. The emission spectra, carrier concentrations in the quantum wells (QWs), energy band diagrams, electrostatic fields, and internal quantum efficiency are investigated. The results indicate that the LED with AlGaN barriers has a better hole-injection efficiency and an enhanced carrier confinement in its active region over the conventional counterpart with GaN barriers. The results also show that the AlGaN electron-blocking layer (EBL) with a gradual variation of Al mole fraction has a significantly enhanced electron blocking capability as well as a greatly improved hole-injection efficiency. When Al0.08Ga 0.92N QW barriers and the special designed EBL are used, the electroluminescence emission intensity is increased greatly by 69 at 200 A/cm2 and the efficiency droop is reduced markedly to 8.7 from 85 at 400 A/cm2 compared with those of the conventional LED. © 2011 American Institute of Physics.


Zhang Y.-Y.,Hong Kong University of Science and Technology | Zhu X.-L.,Hong Kong University of Science and Technology | Yin Y.-A.,South China Normal University | Ma J.,Hong Kong University of Science and Technology
IEEE Electron Device Letters | Year: 2012

In this study, the characteristics of the nitride-based near-UV light-emitting diode (LED) with an InAlN/GaN superlattice (SL) electron-blocking layer (EBL) are analyzed numerically and experimentally. The emission spectra, carrier concentrations in the quantum wells, energy-band diagrams, electrostatic fields, and internal quantum efficiency are investigated. The results indicate that the LED with an InAlN/GaN SL EBL has a better hole-injection efficiency and lower electron leakage over the LED with a conventional rectangular AlGaN EBL or with an AlGaN/GaN SL EBL. The results also show that the efficiency droop is markedly improved when the InAlN/GaN SL EBL is used. © 2012 IEEE.


Zuo X.,South China Normal University | Fan C.,South China Normal University | Liu J.,Guangzhou Tinci Materials Technology Co. | Xiao X.,South China Normal University | And 2 more authors.
Journal of Power Sources | Year: 2013

This study demonstrates that tris(trimethylsilyl)borate (TMSB) additive in the electrolyte can dramatically improve the cycling performance of LiNi0.5Co0.2Mn0.3O2/graphite cell at higher voltage operation. And the effects of this additive are characterized by linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). In the voltage range of 3.0-4.4 V, LiNi0.5Co0.2Mn0.3O2/graphite cell with TMSB in the electrolyte retains about 92.3% of its initial capacity compared to the cell without additive in the electrolyte that retains only 28.5% of its initial capacity after 150 cycles, showing the promising prospect of TMSB at higher voltage. The enhanced cycling performance is attributed to the thinner film originated from TMSB on the LiNi0.5Co0.2Mn0.3O2 and the combination of TMSB with PF6 - and F- in the electrolyte, which not only protects the undesirable decomposition of EC solvents but also results in lower interfacial impedance. © 2012 Elsevier B.V. All rights reserved.


Qiu Y.,Hong Kong University of Science and Technology | Xu G.-L.,Xiamen University | Yan K.,Hong Kong University of Science and Technology | Sun H.,Hong Kong University of Science and Technology | And 5 more authors.
Journal of Materials Chemistry | Year: 2011

By means of morphology-conserved transformation, we have synthesized hierarchically structured Mn2O3 nanomaterials with different morphologies and pore structures. The key step of this method consists of the formation of a precursor containing the target materials interlaced with the judiciously chosen polyol-based organic molecules, which are subsequently knocked out to generate the final nanomaterials. In the present work, two kinds of precursor morphologies, oval-shaped and straw-sheaf-shaped, have been selectively prepared by hydrothermal treatment of different functional polyol molecules (oval-shape with fructose and straw-sheaf-shape with β-cyclodextrin) and potassium permanganate. Thermal decomposition of the precursors resulted in the formation of mesoporous Mn2O3 maintaining the original morphologies, as revealed by extensive characterization. These novel hierarchical nanostructures with different pore sizes/structures prompted us to examine their potential as anode materials for lithium ion batteries (LIBs). The electrochemical results with reference to LIBs show that both of our mesoporous Mn2O3 nanomaterials deliver high reversible capacities and excellent cycling stabilities at a current density of 200 mA g-1 compared to the commercial Mn 2O3 nanoparticles. Moreover, the straw-sheaf-shaped Mn2O3 exhibits a higher specific capacity and a better cycling performance than the oval-shaped one, due to the relatively higher surface area and the peculiar nanostrip structure resulting in the reduced length for lithium ion diffusion. Morphology-conserved transformation yields two kinds of hierarchical mesoporous Mn2O3 nanomaterials with high capacities and cycling stabilities for lithium ion batteries. © 2011 The Royal Society of Chemistry.


Zuo X.,South China Normal University | Fan C.,South China Normal University | Xiao X.,South China Normal University | Liu J.,Guangzhou Tinci Materials Technology Co. | Nan J.,South China Normal University
Journal of Power Sources | Year: 2012

In order to overcome the capacity fading of LiCoO 2/graphite Lithium-ion batteries (LIBs) cycled in the voltage range of 3.0-4.5 V (vs. Li/Li +), methylene methanedisulfonate (MMDS) is newly evaluated as an electrolyte additive. The linear sweep voltammetry (LSV) and cyclic voltammetry (CV) indicate that MMDS has a lower oxidation potential in the mixed solvents of ethylene carbonate (EC) and ethyl methyl carbonate (EMC), and participates in the formation process of the cathode electrolyte interface (CEI) film. With the addition of 0.5 wt.% MMDS into the electrolyte, the capacity retention of the LiCoO 2/graphite cells cycled in 3.0-4.5 V is significantly increased from 32.0% to 69.6% after 150 cycles, and the rate capacity is also improved compared with the cells without MMDS additive in the electrolyte, showing the promising prospect in the electrolyte. In addition, the results of electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) demonstrate that the enhanced electrochemical performances of the cells can be ascribed to the modification of components of cathodes surface layer in the presence of MMDS, which resulting the suppression of the electrolyte oxidized decomposition and the improvement of CEI conductivity. © 2012 Elsevier B.V. All rights reserved.


Jin L.,South China Normal University | Qiu Y.,Hong Kong University of Science and Technology | Deng H.,South China Normal University | Li W.,South China Normal University | And 2 more authors.
Electrochimica Acta | Year: 2011

We report here a polymer-templated hydrothermal growth method and subsequent calcination to achieve carbon coated hollow CuFe2O 4 spheres (H-CuFe2O4@C). This material, when used as anode for Li-ion battery, retains a high specific capacity of 550 mAh g-1 even after the 70th cycle, which is much higher than those of both CuFe2O4@C (∼300 mAh g-1) and H-CuFe2O4 (∼120 mAh g-1). And galvanostatic cycling at different current densities reveals that a capacity of 480 mAh g-1, 91% recovery of the specific capacity cycling at 100 mA g -1, can be obtained even after 50 cycles running from 100 to 1600 mA g-1. The significantly enhanced electrochemical performances of H-CuFe2O4@C with regard to Li-ion storage are ascribed to the following factors: (1) the hollow void, which could mitigate the pulverization of electrode and facilitate the lithium-ion, electron and electrolyte transport; (2) the conductive carbon coating, which could enhance the conductivity, alleviate the agglomeration problem, prevent the formation of an overly thick SEI film and buffer the electrode. Such a structural motif of H-CuFe2O4@C is promising, for electrode materials of LIBs, and points out a general strategy for creating other hollow-shell electrode materials with improved electrochemical performances. © 2011 Elsevier Ltd. All rights reserved.


Qiu Y.,Hong Kong University of Science and Technology | Yan K.,Hong Kong University of Science and Technology | Deng H.,Hong Kong University of Science and Technology | Deng H.,South China Normal University | Yang S.,Hong Kong University of Science and Technology
Nano Letters | Year: 2012

A photoanode based on ZnO nanotetrapods, which feature good vectorial electron transport and network forming ability, has been developed for efficient photoelectrochemical water splitting. Two strategies have been validated in significantly enhancing light harvesting. The first was demonstrated through a newly developed branch-growth method to achieve secondary and even higher generation branching of the nanotetrapods. Nitrogen-doping represents the second strategy. The pristine ZnO nanotetrapod anode yielded a photocurrent density higher than those of the corresponding nanowire devices reported so far. This photocurrent density was significantly increased for the new photoanode architecture based on the secondary branched ZnO nanotetrapods. After N-doping, the photocurrent density enjoyed an even more dramatic enhancement to 0.99 mA/cm 2 at +0.31 V vs Ag/AgCl. The photocurrent enhancement is attributed to the greatly increased roughness factor for boosting light harvesting associated with the ZnO nanotetrapod branching, and the increased visible light absorption due to the N-doping induced band gap narrowing of ZnO. © 2011 American Chemical Society.


Yuan P.,South China Normal University | Ding C.,Hong Kong University of Science and Technology
Finite Fields and their Applications | Year: 2011

Using a lemma proved by Akbary, Ghioca, and Wang, we derive several theorems on permutation polynomials over finite fields. These theorems give not only a unified treatment of some earlier constructions of permutation polynomials, but also new specific permutation polynomials over Fq. A number of earlier theorems and constructions of permutation polynomials are generalized. The results presented in this paper demonstrate the power of this lemma when it is employed together with other techniques. © 2011 Elsevier Inc. All Rights Reserved.


Qiu Y.,Hong Kong University of Science and Technology | Yang S.,Hong Kong University of Science and Technology | Deng H.,South China Normal University | Jin L.,South China Normal University | Li W.,South China Normal University
Journal of Materials Chemistry | Year: 2010

In this paper, we report a successful synthesis of porous ZnCo 2O4 nanoflakes by a morphology-conserved and pyrolysis-induced transformation of novel hexagonally shaped, highly ordered, and inorganic-organic-inorganic layered hybrid nanodisks. It is shown that the hexagonal hybrid nanodisks are constructed from organic molecule (ethylene glycol)-directed assembly of inorganic bilayers. The assembly mechanism has been established by a number of structural and spectroscopic techniques. The porous ZnCo2O4 nanoflakes have also been tested as a lithium ion battery electrode, showing high capacity and high cyclability. © The Royal Society of Chemistry 2010.


Liao K.,South China Normal University | Yan H.,South China Normal University | He J.,South China Normal University | Du S.,Hong Kong University of Science and Technology | And 4 more authors.
Physical Review Letters | Year: 2014

We demonstrate an efficient experimental scheme for producing polarization-entangled photon pairs from spontaneous four-wave mixing (SFWM) in a laser-cooled Rb85 atomic ensemble, with a bandwidth (as low as 0.8 MHz) much narrower than the rubidium atomic natural linewidth. By stabilizing the relative phase between the two SFWM paths in a Mach-Zehnder interferometer configuration, we are able to produce all four Bell states. These subnatural-linewidth photon pairs with polarization entanglement are ideal quantum information carriers for connecting remote atomic quantum nodes via efficient light-matter interaction in a photon-atom quantum network. © 2014 American Physical Society.


Zhang Y.-Y.,South China Normal University | Zhang Y.-Y.,Hong Kong University of Science and Technology | Fan G.-H.,South China Normal University | Yin Y.-A.,South China Normal University | Yao G.-R.,South China Normal University
Optics Express | Year: 2012

In this study, the characteristics of the nitride-based blue light-emitting diode (LED) without an electron-blocking layer (EBL) are analyzed numerically. The emission spectra, carrier concentrations in the quantum wells (QWs), energy band diagrams, electrostatic fields, and internal quantum efficiency (IQE) are investigated. The simulation results indicate that the LED without an EBL has a better hole-injection efficiency and smaller electrostatic fields in its active region over the conventional LED with an AlGaN EBL. The simulation results also show that the LED without an EBL has severe efficiency droop. However, when the special designed p-type doped InGaN QW barriers are used, the efficiency droop is markedly improved and the electroluminescence (EL) emission intensity is greatly enhanced which is due to the improvement of the hole uniformity in the active region and small electron leakage. © 2012 Optical Society of America.


Li J.,Nanjing Southeast University | Zhang Y.,South China Normal University | Jin R.,Nanjing Southeast University | Wang Q.,Nanjing University | And 2 more authors.
Optics Letters | Year: 2014

Plasmon toroidal mode is a unique electromagnetic resonance that cannot be expanded by general electronic or magnetic multipoles. Usually, this mode excitation needs complicated nanostructures, which is a challenge for sample fabrications, especially for nanodesigns with optical resonant frequencies. In this work, we designed a circular V-groove array and studied its toroidal-mode excitation by angle-resolved reflection experimentally and numerically. Our results show that a plasmon toroidal mode around wavelength 700 nm can be excited in this simple nanostructure for incident angles larger than 20°. Compared to reported papers, our design can realize the optical excitation of plasmon toroidal mode, which is useful in high-sensitivity plasmon sensors. © 2014 Optical Society of America.


Liang L.,South China Normal University | Peng G.,South China Normal University | Li G.,South China Normal University | Lan Y.,Karlsruhe Institute of Technology | And 2 more authors.
Dalton Transactions | Year: 2012

A family of six dinuclear lanthanide complexes have been obtained via in situ hydrothermal synthesis with lanthanide ions as catalyst. These six complexes are formulated as [Ln 2(3-Htzba) 2(3-tzba) 2(H 2O) 8]·4H 2O [Ln = Gd, 1; Dy, 2; Eu, 3; Tb, 4; Sm, 5; Er, 6; 3-H 2tzba = 3-(1H-tetrazol-5-yl) benzoic acid]. The magnetic investigations show that complex 2 behaves as a single-molecule magnet (SMM) with a quantum relaxation time of ∼10 -2 s. © 2012 The Royal Society of Chemistry.


Chen B.R.,Sun Yat Sen University | Wu M.,South China Normal University
Journal of Regional Science | Year: 2014

This paper, by using annual surveys of Chinese manufacturing firms from 2001 to 2007, investigates the relationship between industrial agglomeration and employer compliance with required pension contributions. The result of panel fixed-effect estimation shows that in the more agglomerated industrial areas, firms comply with pension mandates at a higher level. Our finding is robust to various specifications and estimations employing instrumental variables. © 2013 Wiley Periodicals, Inc.


Chen X.,South China Normal University | Hu W.,Sun Yat Sen University | Wu S.,Sun Yat Sen University | Bao D.,Sun Yat Sen University
Applied Physics Letters | Year: 2014

In this work, amorphous MgZnO/ZnO heterostructure films were deposited on Pt/TiO2/SiO2/Si at room temperature. By programming the proper compliance current, bipolar resistive switching performances of TiN/MgZnO/ZnO/Pt devices were stabilized; the dispersion of switching voltages and resistance states of devices were suppressed simultaneously. In view of filamentary model, the elimination of secondary and multiple nanofilaments in higher compliance current was suggested to be responsible for the observed improvement. Furthermore, the good endurance and retention behaviors of the optimized TiN/MgZnO/ZnO/Pt devices were confirmed, ensuring its potential application for resistive random access memory. This simple optimizing method by programming proper compliance current is promising for resistive switching devices required avoiding damage. © 2014 AIP Publishing LLC.


Xiao J.,South China Normal University | Li L.,Sun Yat Sen University
Expert Systems with Applications | Year: 2011

Research on optimization in continuous domains gains much of focus in swarm computation recently. A hybrid ant colony optimization approach which combines with the continuous population-based incremental learning and the differential evolution for continuous domains is proposed in this paper. It utilizes the ant population distribution and combines the continuous population-based incremental learning to dynamically generate the Gaussian probability density functions during evolution. To alleviate the less diversity problem in traditional population-based ant colony algorithms, differential evolution is employed to calculate Gaussian mean values for the next generation in the proposed method. Experimental results on a large set of test functions show that the new approach is promising and performs better than most of the state-of-the-art ACO algorithms do in continuous domains. © 2011 Elsevier Ltd. All rights reserved.


Shi C.,Hainan Normal University | Dai X.,Sun Yat Sen University | Liang P.,Sun Yat Sen University | Liang P.,JiShou University | Zhang H.,South China Normal University
IEEE Transactions on Wireless Communications | Year: 2012

How to improve the short-term fairness and increase the aggregated throughput simultaneously is a major problem in WLANs, yet has not been solved satisfactorily in previous work, especially in the situation that network loads vary significantly. To improve the performance in saturation state, we propose a novel access mechanism that sets an optimal Contention Window (CW) for all nodes in the network. By introducing a new parameter of CW Index (CWI), we present a linear CW adjustment rule based on the active node number and then develop an estimation algorithm of node number with three thresholds. Compared to previous algorithms, the new algorithm predicts the future node number based on the current network status, thus minimizes the fluctuating effect of idle slot intervals observed at each process. Moreover, it can identify the dense degree of idle slot intervals and track the changes of the accurate node number quickly. By selecting the optimal CWI adaptively, the maximum aggregated throughput keeps basically a constant despite the variation of the number of nodes. Meanwhile, by eliminating multiple transmission attempts of the same node, the short-term fairness is improved significantly. To evaluate the mechanism, we derive closed-form expressions for the network performance. The simulation results demonstrate the validity and good scalability of the proposed access mechanism. © 2012 IEEE.


Li X.,South China Normal University | Cao Y.,Sun Yat Sen University | Yang G.,Sun Yat Sen University
Physical Chemistry Chemical Physics | Year: 2010

A thermodynamic model has been proposed to address the transition from the two-dimensional to three-dimensional growth modes in the quantum dots self-assembly. It was found that the surface energy density of substrates and the mismatch between quantum dots and substrates play key roles in the transition of the growth modes. The high (low) surface energy density of substrate and the low (high) mismatch between quantum dots and substrate result in the large (small) critical thickness of the wetting layer, which further determines the growth mode of quantum dots. These findings suggested that we could control the transition of the quantum dots growth mode by substrate manipulation. The theoretical results were consistent with experimental observations, which implied that the established thermodynamic theory could be expected to be a general approach for pursuing the evolution of the growth mode in the quantum dots self-assembly. © the Owner Societies.


Zhang X.,South China Normal University | Zhang X.,University of Tennessee at Knoxville | Paquette M.R.,University of Memphis | Zhang S.,University of Tennessee at Knoxville
Journal of Foot and Ankle Research | Year: 2013

Background: Flip-flops and sandals are popular choices of footwear due to their convenience. However, the effects of these types of footwear on lower extremity biomechanics are still poorly understood. Therefore, the objective of this study was to investigate differences in ground reaction force (GRF), center of pressure (COP) and lower extremity joint kinematic and kinetic variables during level-walking in flip-flops, sandals and barefoot compared to running shoes. Methods: Ten healthy males performed five walking trials in the four footwear conditions at 1.3 m/s. Three-dimensional GRF and kinematic data were simultaneously collected. Results: A smaller loading rate of the 1st peak vertical GRF and peak propulsive GRF and greater peak dorsiflexion moment in early stance were found in shoes compared to barefoot, flip-flops and sandals. Barefoot walking yielded greater mediolateral COP displacement, flatter foot contact angle, increased ankle plantarflexion contact angle, and smaller knee flexion contact angle and range of motion compared to all other footwear. Conclusions: The results from this study indicate that barefoot, flip-flops and sandals produced different peak GRF variables and ankle moment compared to shoes while all footwear yield different COP and ankle and knee kinematics compared to barefoot. The findings may be helpful to researchers and clinicians in understanding lower extremity mechanics of open-toe footwear. © 2013 Zhang et al.; licensee BioMed Central Ltd.


Shu Y.,South China Normal University | Lam Nina S.N. N.S.N.,Louisiana State University
Atmospheric Environment | Year: 2011

Detailed estimates of carbon dioxide emissions at fine spatial scales are critical to both modelers and decision makers dealing with global warming and climate change. Globally, traffic-related emissions of carbon dioxide are growing rapidly. This paper presents a new method based on a multiple linear regression model to disaggregate traffic-related CO 2 emission estimates from the parish-level scale to a 1×1km grid scale. Considering the allocation factors (population density, urban area, income, road density) together, we used a correlation and regression analysis to determine the relationship between these factors and traffic-related CO 2 emissions, and developed the best-fit model. The method was applied to downscale the traffic-related CO 2 emission values by parish (i.e. county) for the State of Louisiana into 1-km 2 grid cells. In the four highest parishes in traffic-related CO 2 emissions, the biggest area that has above average CO 2 emissions is found in East Baton Rouge, and the smallest area with no CO 2 emissions is also in East Baton Rouge, but Orleans has the most CO 2 emissions per unit area. The result reveals that high CO 2 emissions are concentrated in dense road network of urban areas with high population density and low CO 2 emissions are distributed in rural areas with low population density, sparse road network. The proposed method can be used to identify the emission " hot spots" at fine scale and is considered more accurate and less time-consuming than the previous methods. © 2010 Elsevier Ltd.


Zhu S.-L.,Nanjing University | Zhu S.-L.,South China Normal University | Zhu S.-L.,University of Hong Kong | Wang Z.-D.,University of Hong Kong | And 4 more authors.
Physical Review Letters | Year: 2013

We study topological properties of the Bose-Hubbard model with repulsive interactions in a one-dimensional optical superlattice. We find that the Mott insulator states of the single-component (two-component) Bose-Hubbard model under fractional fillings are topological insulators characterized by a nonzero charge (or spin) Chern number with nontrivial edge states. For ultracold atomic experiments, we show that the topological Chern number can be detected through measuring the density profiles of the bosonic atoms in a harmonic trap. © 2013 American Physical Society.


Wang H.,South China Normal University | Luo C.,South China Normal University | Zhong L.,South China Normal University | Ma S.,Hans Tech | Lu X.,South China Normal University
Optics Express | Year: 2014

From three interferograms with unknown phase shifts, an innovative phase retrieval approach based on the normalized difference maps is proposed. Using the subtraction operation between interferograms, two difference maps without background can be achieved. To eliminate the amplitude inequality of difference maps, normalization process is employed so that two normalized difference maps are obtained. Finally, combining two normalized difference maps and two-step phase retrieval algorithm, the measured phase with high precision can be retrieved rapidly. Comparing with the conventional two-step phase retrieval algorithm with high-pass filtering, the accuracy and processing time of the proposed approach are greatly improved. Importantly, when the phase shift is close to π, almost all two-step algorithms become invalid, but the proposed approach still performs well. That is, the proposed normalized difference maps approach is suitable for the phase retrieval with arbitrary phase shifts. © 2014 Optical Society of America.


Li J.,South China Normal University | Shen L.,Xinjiang Normal University | Pan Y.,South China Normal University | Li R.,South China Normal University
Optics Express | Year: 2014

A method for optical image hiding and for optical image encryption and hiding in the Fresnel domain via completely optical means is proposed, which encodes original object image into the encrypted image and then embeds it into host image in our modified Mach-Zehnder interferometer architecture. The modified Mach-Zehnder interferometer not only provides phase shifts to record complex amplitude of final encrypted object image on CCD plane but also introduces host image into reference path of the interferometer to hide it. The final encrypted object image is registered as interference patterns, which resemble a Fresnel diffraction pattern of the host image, and thus the secure information is imperceptible to unauthorized receivers. The method can simultaneously realize image encryption and image hiding at a high speed in pure optical system. The validity of the method and its robustness against some common attacks are investigated by numerical simulations and experiments. © 2014 Optical Society of America.


Pan H.,South China Normal University | Xing R.,Sun Yat Sen University
Nonlinear Analysis: Real World Applications | Year: 2012

In this paper, we consider a one-dimensional prescribed mean curvature problem related to MEMS models. We obtain all exact multiplicity for classical solutions and non-classical solutions when the length L of the interval and the parameter λ change. As a by-product, it also provides a complete analytic proof for an interesting new phenomenon, which is first noticed by Brubaker and Pelesko. Our methods are based on a detailed analysis of time maps. © 2012 Elsevier Ltd. All rights reserved.


Wei Y.,Sun Yat Sen University | Chen Y.,South China Normal University
Advances in Applied Mathematics and Mechanics | Year: 2012

The theory of a class of spectral methods is extended to Volterra integro- differential equations which contain a weakly singular kernel (t - s) -μ with 0 < μ < 1. In this work, we consider the case when the underlying solutions of weakly singular Volterra integro-differential equations are sufficiently smooth. We provide a rigorous error analysis for the spectral methods, which shows that both the errors of approximate solutions and the errors of approximate derivatives of the solutions decay exponentially in L ∞-norm and weighted L 2-norm. The numerical examples are given to illustrate the theoretical results. © 2012 Global Science Press.


Zhang D.-W.,South China Normal University | Fu L.-B.,CAS Beijing Institute of Applied Physics And Computational Mathematics | Wang Z.D.,University of Hong Kong | Zhu S.-L.,South China Normal University | Zhu S.-L.,Tsinghua University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We investigate the quantum dynamics of an experimentally realized spin-orbit-coupled Bose-Einstein condensate in a double-well potential. The spin-orbit coupling can significantly enhance the atomic interwell tunneling. We find the coexistence of internal and external Josephson effects in the system, which are moreover inherently coupled in a complicated form even in the absence of interatomic interactions. Moreover, we show that the spin-dependent tunneling between two wells can induce a net atomic spin current referred as spin Josephson effects. Such spin Josephson effects can be observable under realistic conditions. © 2012 American Physical Society.


Li G.-B.,Sun Yat Sen University | Liu J.-M.,Sun Yat Sen University | Cai Y.-P.,South China Normal University | Su C.-Y.,Sun Yat Sen University
Crystal Growth and Design | Year: 2011

A series of Mn(II), Cd(II), and Co(II) metal-organic frameworks, namely, {[Mn(L1)(NCS)2(CH3OH)2] ·2(CH3OH)}n (1), {[Mn(L2) 2(NCS)2(CH3OH)2]}n (2), {[Mn(L3)2(NCS)2] ·0.5(CH3OH) ·4.5H2O}n (3), {[Cd(L1)(I)2] ·3(H2O)}n (4), {[Cd(L2)(I) 2]}n (5), {[Cd(L3)(NCS)2] ·2.5(H2O)}n (6), {[Co(L1) 2(NCS)2] ·4(H2O)}n (7), {[Co(L2)2(NCS)2] · (HCCl3) }n (8), and {[Co(L3)2(NCS)2] ·3(H2O)}n (9) (where L1 = N,N′-bis(4-pyridylmethyl)-pyromellitic diimide, L2 = N,N′-bis(3-pyridylmethyl)-pyromellitic diimide, L3 = N,N′-bis(4-pyridylmethyl)-naphthalene diimide), were synthesized and structurally characterized by elemental analyses, thermogravimetric (TG) analyses, powder X-ray diffraction, IR spectroscopy, and single-crystal X-ray diffraction. In Mn(II) complexes 1-3, L1 connects the adjacent metal centers to form an infinite one-dimensional (1D) zigzag coordination polymeric chain, L2 acts as a monodentate ligand to give mononuclear coordination motifs, while L3 bridges two metal ions to generate two-dimensional (2D) networks of the (4, 4) net topology containing rhombic grids. In Cd(II) complexes 4-6, L1, L2, and L3 act as bidentate ligands and coordinate with two metal ions to form three different coordination polymers that display diversified structures, that is, infinite 1D zigzag chain in 4, single-stranded double helical chain in 5, and 2D networks of the (4, 4) net in 6. For three Co(II) complexes, 7 is a three-dimensional (3D) framework with 3-fold interpenetrating dia topology, while 8 and 9 have similar two-dimensional (2D) networks of the (4, 4) net topology. The results show that the conformation and coordination mode of organic ligands and the coordination geometry of metal centers play important roles in determining the structure and topology of the complexes. Furthermore, the gas sorption properties were measured, and complex 7 shows a highly selective sorption behavior toward CO2, which can be a promising candidate as adsorbents for CO2/N2 separation. In addition, the luminescence properties of 5-6 were studied in the solid state at room temperature. © 2011 American Chemical Society.


Hu W.,Sun Yat Sen University | Zou L.,Sun Yat Sen University | Chen X.,South China Normal University | Qin N.,Sun Yat Sen University | And 2 more authors.
ACS Applied Materials and Interfaces | Year: 2014

We report on highly uniform resistive switching properties of amorphous InGaZnO (a-IGZO) thin films. The thin films were fabricated by a low temperature photochemical solution deposition method, a simple process combining chemical solution deposition and ultraviolet (UV) irradiation treatment. The a-IGZO based resistive switching devices exhibit long retention, good endurance, uniform switching voltages, and stable distribution of low and high resistance states. Electrical conduction mechanisms were also discussed on the basis of the current-voltage characteristics and their temperature dependence. The excellent resistive switching properties can be attributed to the reduction of organic- and hydrogen-based elements and the formation of enhanced metal-oxide bonding and metal-hydroxide bonding networks by hydrogen bonding due to UV irradiation, based on Fourier-transform-infrared spectroscopy, X-ray photoelectron spectroscopy, and Field emission scanning electron microscopy analysis of the thin films. This study suggests that a-IGZO thin films have potential applications in resistive random access memory and the low temperature photochemical solution deposition method can find the opportunity for further achieving system on panel applications if the a-IGZO resistive switching cells were integrated with a-IGZO thin film transistors. © 2014 American Chemical Society.


Lu Y.-Y.,South China Normal University | Chen T.-S.,Sun Yat Sen University | Wang X.-P.,Jinan University | Li L.,Sun Yat Sen University
Journal of Biomedical Optics | Year: 2010

Dihydroartemisinin (DHA), a front-line antimalarial herbal compound, has been shown to possess promising anticancer activity with low toxicity. We have previously reported that DHA induced caspase-3-dependent apoptosis in human lung adenocarcinoma cells. However, the cellular target and molecular mechanism of DHAinduced apoptosis is still poorly defined. We use confocal fluorescence microscopy imaging, fluorescence resonance energy transfer, and fluorescence recovery after photobleaching techniques to explore the roles of DHA-elicited reactive oxygen species (ROS) in the DHAinduced Bcl-2 family proteins activation, mitochondrial dysfunction, caspase cascade, and cell death. Cell Counting Kit-8 assay and flow cytometry analysis showed that DHA induced ROS-mediated apoptosis. Confocal imaging analysis in a single living cell and Western blot assay showed that DHA triggered ROS-dependent Bax translocation, mitochondrial membrane depolarization, alteration of mitochondrial morphology, cytochrome c release, caspase-9, caspase-8, and caspase-3 activation, indicating the coexistence of ROS-mediated mitochondrial and death receptor pathway. Collectively, our findings demonstrate for the first time that DHA induces cell apoptosis by triggering ROS-mediated caspase-8/Bid activation and the mitochondrial pathway, which provides some novel insights into the application of DHA as a potential anticancer drug and a new therapeutic strategy by targeting ROS signaling in lung adenocarcinoma therapy in the future. © 2010 Society of Photo Optical Instrumentation Engineers.


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

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


Zheng S.-R.,South China Normal University | Cai S.-L.,South China Normal University | Pan M.,Sun Yat Sen University | Fan J.,South China Normal University | And 2 more authors.
CrystEngComm | Year: 2011

Reaction of Cd(ii), Fe(ii), and Cu(ii) with a new ligand 2-(hydroxymethyl)-1H-imidazole-4,5-dicarboxylic acid (H4hmIDC) and 4,4′-bipyridine (bpy) affords three coordination polymers of {[Cd(H 2hmIDC)(bpy)]·0.5bpy·H2O}n (1), [Fe2(HhmIDC)2]n (2), and {[Cu 2(ITC)(bpy)(H2O)3]·2.5H 2O}n (3) (ITC = imidazole-2,4,5-tricarboxylic acid), respectively. Complex 1 and complex 3 are (4,4) nets in topological view and display in different packing mode, while hydroxymethyl group in complex 3 is oxidized to carboxylic group in situ. Complex 2 is a rare example of a cdl-e network containing both tetrahedral and square nodes. The hydroxymethyl groups act as a precursor and undergo different reactions directed by metal ions. © 2011 The Royal Society of Chemistry.


Zheng X.,South China Normal University | Zheng X.,Sun Yat Sen University | Zhou F.,South China Normal University | Zhou F.,Sun Yat Sen University | And 5 more authors.
Molecular Pharmaceutics | Year: 2012

Indocyanine green (ICG) is a conventional dye that can be used in clinical near-infrared (NIR) imaging, and it is also an effective light absorber for laser-mediated photothermal therapy. However, applications of ICG were limited due to its fast degradation in aqueous media and quick clearance from the body. Herein, an ICG-containing nanostructure, ICG-PL-PEG, was developed for photothermal therapy, which was self-assembled by ICG and phospholipid- polyethylene glycol (PL-PEG). Our in vitro and in vivo experiments demonstrated that ICG-PL-PEG suspension was more efficient in producing a NIR-dependent temperature increase than ICG alone, due to the increase of ICG monomers from the addition of PL-PEG to match the central wavelength of the 808 nm laser. When conjugated with integrin α vβ 3 monoclonal antibody (mAb), ICG-PL-PEG could be selectively internalized and retained in target tumor cells. Irradiation of an 808 nm laser after intravenous administration of ICG-PL-PEG-mAb resulted in tumor suppression in mice, while ICG alone had only limited effect. This is the first time an ICG-containing nanostructure has been used through systemic administration to achieve an efficient in vivo photothermal effect for cancer treatment. Therefore, ICG-PL-PEG could be used as a fluorescent marker as well as a light-absorber for imaging-guided photothermal therapy. All the components of ICG-PL-PEG have been approved for human use. Therefore, this unique ICG-containing nanostructure has great potential in clinical applications. © 2012 American Chemical Society.


Hui K.S.,Hanyang University | Hui K.N.,Pusan National University | Dinh D.A.,Pusan National University | Tsang C.H.,City University of Hong Kong | And 4 more authors.
Acta Materialia | Year: 2014

A green chemical approach to control the dimensions of Ag nanoparticle-decorated graphene oxide (AgNP-GO) composites was proposed by in situ ultrasonication of a mixture of AgNO3 and GO solution with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. The AgNP-GO composites were characterized by X-ray diffraction, transmission electron microscopy, energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, Raman spectra and ultraviolet-visible absorption spectra. The results demonstrated that Ag nanoparticles with an average diameter of ∼15 nm were uniformly dispersed on the surface of GO nanosheets by in situ ultrasonication of 1 min with vitamin C. Increasing the ultrasonication times resulted in Ag nanoparticles with tunable dimensions ranging from 15 to 55 nm being formed on the surface of GO nanosheets. The amount of silver nitrate and the ultrasonication time play a key role in the control of the dimension of Ag nanoparticles on GO, and a formation mechanism of the as-prepared AgNP-GO composites is proposed. This study provides a guide to controlling the dimensions of AgNP-GO composites, which may hold promise as advanced materials for various analytical applications such as catalysis, sensors and microchips. © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.


Zhou F.,South China Normal University | Zhou F.,Sun Yat Sen University | Wu S.,South China Normal University | Wu S.,Sun Yat Sen University | And 5 more authors.
Small | Year: 2012

In vitro photoacoustic therapy using modified single-walled carbon nanotubes (SWNTs) as "bomb" agents is a newly reported approach for cancer. Herein, a mitochondria-targeting photoacoustic modality using unmodified SWNTs and its in vitro and in vivo antitumor effect are reported. Unmodified SWNTs can be taken up into cancer cells due to a higher mitochondrial transmembrane potential in cancerous cells than normal cells. Under the irradiation of a 1064 nm pulse laser, 79.4% of cancer cells with intracellular SWNTs die within 20 s, while 82.3% of normal cells without SWNTs remain alive. This modality kills cancer cells mainly by triggering cell apoptosis that initiates from mitochondrial damage, through the depolarization of mitochondria and the subsequent release of cytochrome c after photoacoustic therapy. It is very effective in suppressing tumor growth by selectively destroying tumor tissue without causing epidermis injury. Taken together, these discoveries provide a new method using mitochondria-localized SWNTs as photoacoustic transducers for cancer treatment. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wen J.,Sun Yat Sen University | Li S.,Sun Yat Sen University | Lin Z.,Guangdong Polytechnic Normal University | Hu Y.,Sun Yat Sen University | Huang C.,South China Normal University
Information and Software Technology | Year: 2012

Context: Software development effort estimation (SDEE) is the process of predicting the effort required to develop a software system. In order to improve estimation accuracy, many researchers have proposed machine learning (ML) based SDEE models (ML models) since 1990s. However, there has been no attempt to analyze the empirical evidence on ML models in a systematic way. Objective: This research aims to systematically analyze ML models from four aspects: type of ML technique, estimation accuracy, model comparison, and estimation context. Method: We performed a systematic literature review of empirical studies on ML model published in the last two decades (1991-2010). Results: We have identified 84 primary studies relevant to the objective of this research. After investigating these studies, we found that eight types of ML techniques have been employed in SDEE models. Overall speaking, the estimation accuracy of these ML models is close to the acceptable level and is better than that of non-ML models. Furthermore, different ML models have different strengths and weaknesses and thus favor different estimation contexts. Conclusion: ML models are promising in the field of SDEE. However, the application of ML models in industry is still limited, so that more effort and incentives are needed to facilitate the application of ML models. To this end, based on the findings of this review, we provide recommendations for researchers as well as guidelines for practitioners. © 2011 Elsevier B.V. All rights reserved.


Pan Y.,Sun Yat Sen University | Luo H.-X.,Sun Yat Sen University | Tang Y.,South China Normal University | Huang C.-Q.,South China Normal University
Knowledge-Based Systems | Year: 2011

The problem of "Learning to rank" is a popular research topic in Information Retrieval (IR) and machine learning communities. Some existing list-wise methods, such as AdaRank, directly use the IR measures as performance functions to quantify how well a ranking function can predict rankings. However, the IR measures only count for the document ranks, but do not consider how well the algorithm predicts the relevance scores of documents. These methods do not make best use of the available prior knowledge and may lead to suboptimal performance. Hence, we conduct research by combining both the document ranks and relevance scores. We propose a novel performance function that encodes the relevance scores. We also define performance functions by combining our proposed one with MAP or NDCG, respectively. The experimental results on the benchmark data collections show that our methods can significantly outperform the state-of-the-art AdaRank baselines. © 2010 Elsevier B.V. All rights reserved.


Fan F.,South China Normal University | Fan F.,Indiana University | Zhang Y.,Florida State University | Yang Y.,Florida State University | And 3 more authors.
Journal of Traumatic Stress | Year: 2011

This study examined the symptoms of posttraumatic stress disorder (PTSD), anxiety, and depression among 2,250 adolescents 6 months after the 2008 Wenchuan earthquake in China. Results showed that 15.8%, 40.5%, and 24.5% of participants reported clinical symptoms of PTSD, anxiety, and depression, respectively. Posttraumatic stress disorder, anxiety, and depression were highly comorbid. Risk factors for symptoms of the 3 disorders were female gender, older age, and earthquake disaster exposure. In addition, the interaction effects of residence (urban/rural) and number of siblings of study subjects on symptoms of the 3 disorders were examined. Implications of findings on intervention and prevention of mental health problems among adolescents after experiencing earthquake disasters are discussed. Copyright © 2011 International Society for Traumatic Stress Studies.


Pan H.,South China Normal University | Xing R.,Sun Yat Sen University
Nonlinear Analysis: Real World Applications | Year: 2016

Consider the following problem arising in Micro-Electro-Mechanical Systems (MEMS) [equation presented] where δ>0, p>1 and Ω is a bounded smooth domain in RN(N≥1). We prove that infinite time quenching is impossible for any λ>0 in this problem. It provides a remarkable contrast to the case of δ=0, in which infinite time quenching must happen for some λ when Ω is a ball in RN(N≥8). This means that the presence of the fringing field δ|∇u|2 dramatically changes the quenching behavior of the solution. We also obtain some new results about global convergence and quenching in finite time. © 2016 Elsevier Ltd. All rights reserved.


Yuan P.,South China Normal University | Zeng X.,Sun Yat Sen University
European Journal of Combinatorics | Year: 2010

Let A ⊂ {1, ..., n - 1} and let (x1, ..., xt) ∈ Zt be a sequence of integers with a maximal length such that for all (a1, ..., at) ∈ At, ∑1 ≤ i ≤ t ai xi ≢ 0 (mod n). The authors show that for any sequence of integers (x1, ..., xn + t) ∈ Zn + t, there are b1, ..., bn ∈ A and 1 ≤ k1 < k2 < ⋯ < kn ≤ n + t such that under(∑, 1 ≤ i ≤ n) bi xki ≡ 0 (mod n) . © 2009 Elsevier Ltd. All rights reserved.


McKenzie R.L.,NIWA - National Institute of Water and Atmospheric Research | Aucamp P.J.,Ptersa Environmental Management Consultants | Bais A.F.,Aristotle University of Thessaloniki | Bjorn L.O.,South China Normal University | And 3 more authors.
Photochemical and Photobiological Sciences | Year: 2011

The Montreal Protocol is working, but it will take several decades for ozone to return to 1980 levels. The atmospheric concentrations of ozone depleting substances are decreasing, and ozone column amounts are no longer decreasing. Mid-latitude ozone is expected to return to 1980 levels before mid-century, slightly earlier than predicted previously. However, the recovery rate will be slower at high latitudes. Springtime ozone depletion is expected to continue to occur at polar latitudes, especially in Antarctica, in the next few decades. Because of the success of the Protocol, increases in UV-B radiation have been small outside regions affected by the Antarctic ozone hole, and have been difficult to detect. There is a large variability in UV-B radiation due to factors other than ozone, such as clouds and aerosols. There are few long-term measurements available to confirm the increases that would have occurred as a result of ozone depletion. At mid-latitudes UV-B irradiances are currently only slightly greater than in 1980 (increases less than ∼5%), but increases have been substantial at high and polar latitudes where ozone depletion has been larger. Without the Montreal Protocol, peak values of sunburning UV radiation could have been tripled by 2065 at mid-northern latitudes. This would have had serious consequences for the environment and for human health. There are strong interactions between ozone depletion and changes in climate induced by increasing greenhouse gases (GHGs). Ozone depletion affects climate, and climate change affects ozone. The successful implementation of the Montreal Protocol has had a marked effect on climate change. The calculated reduction in radiative forcing due to the phase-out of chlorofluorocarbons (CFCs) far exceeds that from the measures taken under the Kyoto protocol for the reduction of GHGs. Thus the phase-out of CFCs is currently tending to counteract the increases in surface temperature due to increased GHGs. The amount of stratospheric ozone can also be affected by the increases in the concentration of GHGs, which lead to decreased temperatures in the stratosphere and accelerated circulation patterns. These changes tend to decrease total ozone in the tropics and increase total ozone at mid and high latitudes. Changes in circulation induced by changes in ozone can also affect patterns of surface wind and rainfall. The projected changes in ozone and clouds may lead to large decreases in UV at high latitudes, where UV is already low; and to small increases at low latitudes, where it is already high. This could have important implications for health and ecosystems. Compared to 1980, UV-B irradiance towards the end of the 21st century is projected to be lower at mid to high latitudes by between 5 and 20% respectively, and higher by 2-3% in the low latitudes. However, these projections must be treated with caution because they also depend strongly on changes in cloud cover, air pollutants, and aerosols, all of which are influenced by climate change, and their future is uncertain. Strong interactions between ozone depletion and climate change and uncertainties in the measurements and models limit our confidence in predicting the future UV radiation. It is therefore important to improve our understanding of the processes involved, and to continue monitoring ozone and surface UV spectral irradiances both from the surface and from satellites so we can respond to unexpected changes in the future. © 2011 The Royal Society of Chemistry and Owner Societies.


Wu S.,South China Normal University | Wu S.,Sun Yat Sen University | Zhou F.,South China Normal University | Zhou F.,Sun Yat Sen University | And 5 more authors.
Antioxidants and Redox Signaling | Year: 2014

Aims: Here, we develop a novel cancer treatment modality using mitochondria-targeting, high-fluence, low-power laser irradiation (HF-LPLI) in mouse tumor models and explore the mechanism of mitochondrial injury by HF-LPLI. Results: We demonstrated that the initial reaction after photon absorption was photosensitization of cytochrome c oxidase (COX), to inhibit enzymatic activity of COX in situ and cause respiratory chain superoxide anion (O2 -•) burst. We also found that HF-LPLI exerted its main tumor killing effect through mitochondrial O2 -• burst via electron transport chain (ETC). These phenomena were completely absent in the respiration-deficient cells and COX knockdown cells. With a carefully selected irradiation protocol, HF-LPLI could efficaciously destroy tumors. The inhibition of enzymatic activity of COX and generation of O2 -• by HF-LPLI in vivo were also detected. Innovation: It is the first time that the mechanism involved in the interaction between light and its photoacceptor under HF-LPLI treatment is clarified. Our results clearly indicate that HF-LPLI initiates its effects via targeted COX photoinactivation and that the tumor-killing efficacy is dependent of the subsequent mitochondrial O 2 -• burst via ETC. Conclusion: Based on both in vitro and in vivo results, we conclude that HF-LPLI can selectively photoinactivate respiratory chain oxidase to trigger a fatal mitochondrial O2 -• burst, producing oxidative damage on cancer cells. This study opens up the possibilities of applications of HF-LPLI as a mitochondria- targeting cancer phototherapy. Antioxid. Redox Signal. 20, 733-746. © 2014, Mary Ann Liebert, Inc.


Pan Z.-L.,South China Normal University | Chen L.,South China Normal University | Zhang G.-Z.,Sun Yat Sen University
Frontiers of Physics | Year: 2016

The hybrid CMOS molecular (CMOL) circuit, which combines complementary metal–oxide–semiconductor (CMOS) components with nanoscale wires and switches, can exhibit significantly improved performance. In CMOL circuits, the nanodevices, which are called cells, should be placed appropriately and are connected by nanowires. The cells should be connected such that they follow the shortest path. This paper presents an efficient method of cell allocation in CMOL circuits with the hybrid CMOS/nanodevice structure; the method is based on a cultural algorithm with chaotic behavior. The optimal model of cell allocation is derived, and the coding of an individual representing a cell allocation is described. Then the cultural algorithm with chaotic behavior is designed to solve the optimal model. The cultural algorithm consists of a population space, a belief space, and a protocol that describes how knowledge is exchanged between the population and belief spaces. In this paper, the evolutionary processes of the population space employ a genetic algorithm in which three populations undergo parallel evolution. The evolutionary processes of the belief space use a chaotic ant colony algorithm. Extensive experiments on cell allocation in benchmark circuits showed that a low area usage can be obtained using the proposed method, and the computation time can be reduced greatly compared to that of a conventional genetic algorithm. © 2016, Higher Education Press and Springer-Verlag Berlin Heidelberg.


Zhu D.,South China Normal University | Zhang L.,Guangzhou University | Ma W.,Guangzhou Nansha Center for Disease Control and oPrevention | Lu S.,Sun Yat Sen University | Xing X.,South China Normal University
Biosensors and Bioelectronics | Year: 2015

MicroRNAs (miRNAs) are a kind of small molecules that involve in many important life activities. They have higher expression levels in many kinds of cancers. In this study, we developed an isothermal enzyme-free amplification (EFA) and label-free graphene oxide (GO)-based SYBR Green I fluorescence platform for detection of miRNA. MiRNA-21 was used as an example to demonstrate the feasibility of the method. Results show that the sensitivity of miRNA-21 is 1pM, and the linearity range is from 1pM to 1nM. The method can specifically discriminate miRNA-21 from miRNA-210 and miRNA-214. Three tumor cell lines of A549, HepG2 and MCF7 were detected by the method. The sensitivities of them were 102 cells, 103 cells and 103 cells respectively. Clinical tumor samples were also tested by this method, and 29 of 40 samples gave out positive signals. The method holds great promise in miRNA detection due to its convenience, rapidness, inexpensive and specificity. © 2014 Elsevier B.V.


Ji Y.,South China Normal University | He Y.,Tsinghua University | Liu L.,Tsinghua University | Zhong X.,Tsinghua University
FEBS Letters | Year: 2010

Here we report that miR-26b is involved in COX-2 overexpression in desferrioxamine (DFOM)-treated carcinoma of nasopharyngeal epithelial (CNE) cells. The level of miR-26b in DFOM-treated CNE cells is inversely proportional to the expression level of the COX-2 protein. Overexpression of miR-26b in DFOM-treated CNE cells inhibits cell proliferation. A luciferase reporter gene experiment suggests that the 3′ untranslated region of COX-2 carries a binding site for miR-26b. Overexpression of miR-26b marginally reduces the levels of COX-2 protein in DFOM-treated CNE cells. Moreover, knockdown of COX-2 expression had a similar effect to overexpression of miR-26b. Taken together, these results suggest that miR-26b regulates COX-2 expression in DFOM-treated cells. © 2010 Federation of European Biochemical Societies.


Yuan P.,South China Normal University | Zeng X.,Sun Yat Sen University
Finite Fields and their Applications | Year: 2011

Kai Zhou (2008) [8] gave an explicit representation of the class of linear permutation polynomials and computed the number of them. In this paper, we give a simple proof of the above results. © 2011 Elsevier Inc. All rights reserved.


Li X.L.,South China Normal University | Li X.L.,Sun Yat Sen University | Wang C.X.,Sun Yat Sen University | Yang G.W.,Sun Yat Sen University
Progress in Materials Science | Year: 2014

Self-assembled nanostructures, such as quantum dots (QDs), quantum rings (QRs) and nanowires (NWs), have been extensively studied because of their physical properties and promising device applications. To improve their physical properties and device applications, the fabrication of nanostructures with a uniform size, proper shape and regular position is desired in nanotechnology. Therefore, investigations of the growth process of nanostructures are highly important to control the self-assembly and synthesis processes of nanostructures flexibly. Thermodynamic theory as a universal approach to investigate material growth has been widely used to study the growth of nanostructures. This review covers the thermodynamic theoretical treatments of the growth of nanostructures, including QDs by epitaxy, QRs by droplet epitaxy, and NWs by the vapor-liquid-solid (VLS) mechanism. First, we introduce the thermodynamic models of the growth mechanisms of QDs by self-assembled epitaxy. The formation, stability, shape and position of QDs are discussed. Second, we introduce the nucleation thermodynamics and the growth kinetics of QRs by droplet epitaxy, and we present a simulation method employing the shape evolution of QRs based on a kinetic model. Third, several theoretical tools are introduced to address the nucleation and growth of NW by the VLS process. Finally, we introduce a thermodynamic treatment including the thermal fluctuations within the context of a statistical mechanical and quantum mechanical model for the temperature-dependent growth of nanostructures. © 2014 Elsevier Ltd. All rights reserved.


Zeng X.,Sun Yat Sen University | Yuan P.,South China Normal University
European Journal of Combinatorics | Year: 2011

Let G be a cyclic group of order n, and let S∈F(G) be a zero-sum sequence of length S≥2[n/2]+2. Suppose that S can be decomposed into a product of at most two minimal zero-sum sequences. Then there exists some g∈G such that S=(n1g)...(n2g)....(n|S|g), where ni∈[1,n] for all i∈[1,|S|] and n1+n2+...+n|S|=2n. And we also generalize the above result to long zero-sum sequences which can be decomposed into at most k≥3 minimal zero-sum sequences. © 2011 Elsevier Ltd.


Zheng S.-R.,South China Normal University | Cai S.-L.,South China Normal University | Yang Q.-Y.,Sun Yat Sen University | Xiao T.-T.,South China Normal University | And 2 more authors.
Inorganic Chemistry Communications | Year: 2011

Two new porous lanthanide-organic frameworks, {[Ln2(HIDC) 3(H2O)2]·7H2O}n [Ln = Tb(1) and Eu(2), H3IDC = imidazole-4,5-dicarboxylic acid], were obtained under hydrothermal conditions. Both of them possess 3D frameworks containing 1D rectangle channels along a-axis. Topological analyses of two complexes reveal that they exhibit unusual 4-nodal (3,4)-connected network. Furthermore, their solid-state luminescent behaviors have been investigated at room temperature. © 2011 Elsevier B.V.


Xiao J.,South China Normal University | Ao X.-T.,Sun Yat Sen University | Tang Y.,South China Normal University
Computers and Operations Research | Year: 2013

Software project scheduling problem (SPSP) is one of the important and challenging problems faced by the software project managers in the highly competitive software industry. As the problem is becoming an NP-hard problem with the increasing numbers of employees and tasks, only a few algorithms exist and the performance is still not satisfying. To design an effective algorithm for SPSP, this paper proposes an ant colony optimization (ACO) approach which is called ACS-SPSP algorithm. Since a task in software projects involves several employees, in this paper, by splitting tasks and distributing dedications of employees to task nodes we get the construction graph for ACO. Six domain-based heuristics are designed to consider the factors of task efforts, allocated dedications of employees and task importance. Among these heuristic strategies, the heuristic of allocated dedications of employees to other tasks performs well. ACS-SPSP is compared with a genetic algorithm to solve the SPSP on 30 random instances. Experimental results show that the proposed algorithm is promising and can obtain higher hit rates with more accuracy compared to the previous genetic algorithm solution. © 2012 Elsevier Ltd. All rights reserved.


Liu L.,South China Normal University | Zhang Z.,South China Normal University | Xing D.,South China Normal University | Xing D.,Sun Yat Sen University
Free Radical Biology and Medicine | Year: 2011

Lysosomal photosensitizers have been used in photodynamic therapy. The combination of such photosensitizers and light causes lysosomal photodamage, inducing cell death. Lysosomal disruption can lead to apoptosis but its signaling pathways remain to be elucidated. In this study, N-aspartyl chlorin e6 (NPe6), an effective photosensitizer that preferentially accumulates in lysosomes, was used to study the mechanism of apoptosis caused by lysosomal photodamage. Apoptosis in living human lung adenocarcinoma cells (ASTC-a-1) after NPe6-photodynamic treatment (NPe6-PDT) was studied using real-time single-cell analysis. Our results demonstrated that NPe6-PDT induced rapid generation of reactive oxygen species (ROS). The photodynamically produced ROS caused a rapid destruction of lysosomes, leading to release of cathepsins, and the ROS scavengers vitamin C and NAC prevent the effects. Then the following spatiotemporal sequence of cellular events was observed during cell apoptosis: Bcl-2-associated X protein (Bax) activation, cytochrome c release, and caspase-9/-3 activation. Importantly, the activation of Bax proved to be a crucial event in this apoptotic machinery, because suppressing the endogenous Bax using siRNA could significantly inhibit cytochrome c release and caspase-9/-3 activation and protect the cell from death. In conclusion, this study demonstrates that PDT with lysosomal photosensitizer induces Bax activation and subsequently initiates the mitochondrial apoptotic pathway. © 2011 Elsevier Inc. All rights reserved.


Wei Y.,Sun Yat Sen University | Chen Y.,South China Normal University
Journal of Scientific Computing | Year: 2012

This paper is concerned with the convergence properties of the Legendre spectral collocation methods when used to approximate smooth solutions of Volterra integro-differential equations with proportional (vanishing) delays. We provide a vigorous error analysis for the proposed methods. Furthermore, we prove that both the errors of approximate solutions and the errors of approximate derivatives decay exponentially in L2-norm and L ∞-norm. Some numerical experiments are given to confirm the theoretical results. © Springer Science+Business Media, LLC 2012.


Cai S.-L.,South China Normal University | Pan M.,Sun Yat Sen University | Zheng S.-R.,South China Normal University | Tan J.-B.,South China Normal University | And 2 more authors.
CrystEngComm | Year: 2012

Three new Cd(ii) coordination polymers with 1H-imidazole-4-carboxylic acid (Himc), [Cd(Himc) 2(H 2O)] n (1), [Cd(Himc) 2] n (2) and [Cd 2(Himc) 2(SO 4)(H 2O) 2] n (3) were perpared by solvothermal reactions and structurally characterized, which all comprised metal-negative ligand systems. Compound 1 exhibit a 1D zigzag chain; compound 2 features a 3D diamondoid work; while compound 3 possesses a 2D layer structure consisting of rhomboid grids. When 1 or 2 was left in a water/ethanolic solution of Na 2SO 4, their 1D or 3D framework was transformed into a 2D framework of 3. All compounds also displayed structure-related photoluminescent properties in the solid state. © 2012 The Royal Society of Chemistry.


Cai S.-L.,South China Normal University | Zheng S.-R.,South China Normal University | Pan M.,Sun Yat Sen University | Tan J.-B.,South China Normal University | And 2 more authors.
CrystEngComm | Year: 2012

An unprecedented trinodal (3,4,14)-connected 3D metal-organic framework formed by planar octanuclear lead(ii) clusters as 14-connected nodes and 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate ligands as 3- and 4-connected nodes has been hydrothermally made. It provides a novel topological structure of metal-organic frameworks. © 2012 The Royal Society of Chemistry.


Zhang Y.-C.,Sun Yat Sen University | Yu Y.,Sun Yat Sen University | Wang C.-Y.,Sun Yat Sen University | Li Z.-Y.,Sun Yat Sen University | And 11 more authors.
Nature Biotechnology | Year: 2013

Increasing grain yields is a major focus of crop breeders around the world. Here we report that overexpression of the rice microRNA (miRNA) OsmiR397, which is naturally highly expressed in young panicles and grains, enlarges grain size and promotes panicle branching, leading to an increase in overall grain yield of up to 25% in a field trial. To our knowledge, no previous report has shown a positive regulatory role of miRNA in the control of plant seed size and grain yield. We determined that OsmiR397 increases grain yield by downregulating its target, OsLAC, whose product is a laccase-like protein that we found to be involved in the sensitivity of plants to brassinosteroids. As miR397 is highly conserved across different species, our results suggest that manipulating miR397 may be useful for increasing grain yield not only in rice but also in other cereal crops. © 2013 Nature America, Inc.


Song L.-Y.,Sun Yat Sen University | Song L.-Y.,South China Normal University | Li C.-H.,CAS South China Botanical Garden | Peng S.-L.,Sun Yat Sen University
Biological Invasions | Year: 2010

Increasing atmospheric CO2 concentration is regarded as an important factor facilitating plants invasions by stimulating invasive species growth. However, the physiological mechanisms by which invasive plants increase at the expense of existing native plants are poorly understood. Plant growth is always related to energy-use process including energy assimilation and expenditure, and thus examination of energetic properties could provide mechanistic insight into growth responses to increased CO2. The aims of this study were to examine the effect of rising CO2 on the growth and energetic properties of alien invasive species (Wedelia trilobata (L.) Hitchc.) and its native congener (Wedelia chinensis (Osbeck.) Merr.) in South China, and to determine if the specific energetic properties of invasive species at elevated CO2 favoring its growth. Elevated CO2 stimulated a greater increase in biomass production for invasive W. trilobata (58.9%) than for its indigenous congener (48.1%). Meanwhile, elevated CO2 altered the energetic properties differently upon species. For invasive W. trilobata, elevated CO2 significantly increased total energetic gain via photosynthetic activity (Atotal), but decreased energetic cost of biomass construction (CC), and thus enhanced photosynthetic energy-use efficiency (PEUE) by 85.3%. In contrast, the indigenous W. chinensis showed a slight increase in PEUE by 43.8%. Additionally, W. trilobata individuals grown in elevated CO2 increased energy allocation towards stems. Statistic analysis revealed significant associations between growth characteristics (relative growth rate and biomass) and energetic properties (CC and PEUE), suggesting the greater growth stimulation in invasive species could be partly explained by its specific energetic properties in elevated CO2 concentration. The invasive species showed a greater increase in energy-use efficiency under elevated CO2, which consequently facilitated its growth. It might be a physiological mechanism promoting success of invasion with ongoing increase in atmospheric CO2 concentration. © Springer Science+Business Media B.V. 2009.


Yao J.-W.,South China Normal University | Zhang C.-Y.,South China Normal University | Liu H.-Y.,South China Normal University | Dai Q.-F.,South China Normal University | And 5 more authors.
Optics Express | Year: 2012

The high spatial frequency periodic structures induced on metal surface by femtosecond laser pulses was investigated experimentally and numerically. It is suggested that the redistribution of the electric field on metal surface caused by the initially formed low spatial frequency periodic structures plays a crucial role in the creation of high spatial frequency periodic structures. The field intensity which is initially localized in the grooves becomes concentrated on the ridges in between the grooves when the depth of the grooves exceeds a critical value, leading to the ablation of the ridges in between the grooves and the formation of high spatial frequency periodic structures. The proposed formation process is supported by both the numerical simulations based on the finite-difference time-domain technique and the experimental results obtained on some metals such as stainless steel and nickel. © 2012 Optical Society of America.


Shen Z.Y.,Tsinghua University | Wang M.,Tsinghua University | Ji Y.H.,South China Normal University | He Y.H.,Tsinghua University | And 3 more authors.
Laser Physics Letters | Year: 2011

We describe a method that uses classic optical coherence tomography to measure the transverse fluid-flow velocity quantitatively without knowing the Doppler angle. An intensity based cross-correlation calculation is taken point-to-pointly between two close cross sections of the scattering fluid to estimate the time delay for scattering particles passing through the two sections which are scanned alternately. The transverse velocity distribution of the scattering fluid-flow in the whole section is achieved finally. The experimental results agree well with the preset ones. This method is insensitive to the Doppler angle and provides a variable velocity detection range in different application conditions. © 2011 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA.


Wang H.,Sun Yat Sen University | Du Y.-J.,South China Normal University | Song H.-C.,Sun Yat Sen University
Food Chemistry | Year: 2010

The 75% ethanol extract from guava (Psidium guajava Linn.) leaves was extracted further, in turn, with CH 2Cl 2, EtOAc and n-BuOH to afford four fractions, CH 2Cl 2-soluble, EtOAc-soluble, n-BuOH-soluble and residual extract fractions. Both the n-BuOH-soluble and EtOAc-soluble fractions showed high inhibitory activity against α-glucosidase and α-amylase. Seven pure flavonoid compounds, quercetin (1), kaempferol (2), guaijaverin (3), avicularin (4), myricetin (5), hyperin (6) and apigenin (7), were isolated (using enzyme assay-guide fractionation method) from the n-BuOH-soluble and EtOAc-soluble fractions. The structures of these pure compounds were determined on the basis of MS and NMR data and the activities of these compounds were evaluated. Compounds 1, 2 and 5 showed high inhibitory activities, with IC 50 values of 3.5 mM, 5.2 mM and 3.0 mM against sucrase, with IC 50 values of 4.8 mM, 5.6 mM and 4.1 mM against maltase and with IC 50 values of 4.8 mM, 5.3 mM and 4.3 mM against α-amylase, respectively. We found that myricetin showed the most powerful activity among these compounds with a 70% inhibition against sucrase at a concentration of 1.5 mg/ml. The hydroxyl group at the 3-position on the A-ring and a number of hydroxyl groups attached to the C-ring played important roles in the inhibition activity. There was an obvious synergistic effect (the mixing action of two compounds) against α-glucosidase, but against α-amylase this was not found. This is the first study of the active compositions of guava leaves and the biological activity of the active compositions against α-glucosidase and α-amylase. © 2010 Elsevier Ltd. All rights reserved.


Hu W.,Sun Yat Sen University | Chen X.,South China Normal University | Wu G.,Sun Yat Sen University | Lin Y.,Sun Yat Sen University | And 2 more authors.
Applied Physics Letters | Year: 2012

We report on the co-existence of bipolar and unipolar resistive switching behaviors in Ag/ZnFe 2O 4/Pt structures of which the ZnFe 2O 4 layer was fabricated by a chemical solution deposition method. The memory devices show reproducible and stable bipolar resistive switching, tri-state unipolar resistive switching under only applied negative bias voltage, and unipolar resistive switching transited from bipolar resistive switching with different electroforming conditions. Excellent switching cycling in both unipolar resistive switching and bipolar resistive switching is demonstrated. Based on the conducting filament model, electrochemical metallization effect has been proposed to explain the bipolar resistive switching behavior, whereas the unipolar resistive switching behavior is attributed to electrochemical metallization effect and thermochemical effect. © 2012 American Institute of Physics.


Lai W.-L.,South China Normal University | Lai W.-L.,Gannan Normal University | Wang S.-Q.,South China Normal University | Peng C.-L.,South China Normal University | Chen Z.-H.,South China Normal University
Water Research | Year: 2011

Morphological, structural, and eco-physiological features of roots, nutrient removal, and correlation between the indices were comparatively studied for 35 emergent wetland plants in small-scale wetlands for further investigation into the hypothesis of two types of wetland plant roots (Chen et al., 2004). Significant differences in root morphological, structural, and eco-physiological features were found among the 35 species. They were divided into two types: fibrous-root plants and thick-root plants. The fibrous-root plants had most or all roots of diameter (D) ≤ 1 mm. Roots of D > 1 mm also had many fine and long lateral roots of D ≤ 1 mm. The roots of these plants were long and had a thin epidermis and a low degree of lignification. The roots of the thick-root plants were almost all thicker than 1 mm, and generally had no further fine lateral roots. The roots were short, smooth, and fleshy, and had a thick epidermis. Root porosity of the fibrous-root plants was higher than that of the thick-root plants (p = 0.001). The aerenchyma of the fibrous-root plants was composed of large cavities which were formed from many small cavities, and distributed radially between the exodermis and vascular tissues. The aerenchyma of the thick-root plants had a large number of small cavities which were distributed in the mediopellis. The fibrous-root plants had a significantly larger root biomass of D ≤ 1 mm, of 1 mm < D < 3 mm, above-ground biomass, total biomass, and longer root system, but shorter root longevity than those of the thick-root plants (p = 0.003, 0.018, 0.020, 0.032, 0.042, 0.001). The fibrous-root plants also had significantly higher radial oxygen loss (ROL), root activity, photosynthetic rate, transpiration rate, and removal rates of total nitrogen and total phosphorus than the thick-root plants (p = 0.001, 0.008, 0.010, 0.004, 0.020, 0.002). The results indicate that significantly different root morphological and structural features existed among different wetland plants, and these features had a close relationship to nutrient removal capacity. © 2011 Elsevier Ltd.


Zhou F.,South China Normal University | Zhou F.,Sun Yat Sen University | Wu S.,South China Normal University | Wu S.,Sun Yat Sen University | And 5 more authors.
Small | Year: 2011

Nanomaterials have recently attracted much attention as efficient transducers for cancer photothermal therapy, based on their intrinsic absorption properties in the near-infrared region. This study explores a novel therapy model with mitochondria-targeting single-walled carbon nanotubes (SWNTs), which act efficiently to convert 980-nm laser energy into heat and selectively destroy the target mitochondria, thereby inducing mitochondrial depolarization, cytochrome c release, and caspase 3 activation. The laser+SWNTs process affords remarkable efficacy in suppressing tumor growth in a breast cancer model, and results in complete tumor regression in some cases. Laser+SWNTs could prove to be a promising selective local treatment modality, while minimizing adverse side effects. A novel therapy model with mitochondria- targeting single-walled carbon nanotubes (SWNTs), which convert laser energy into heat and selectively destroy the target mitochondria, is explored. The procedure induces cytochrome c release and cell apoptosis. The laser-SWNT method could be a promising selective local treatment modality, while minimizing adverse side effects. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Song J.,South China Normal University | Chen Q.,South China Normal University | Chen Q.,Sun Yat Sen University | Xing D.,South China Normal University | Xing D.,Sun Yat Sen University
Experimental Cell Research | Year: 2013

Tumor cells exposed to sub-lethal photodynamic therapy (PDT) cause cellular rescue responses that lead to resistance to the therapy, including expression of angiogenic factors and survival molecules. However, the mechanisms contributing to the resistance are yet to be fully understood. Here, we show for the first time that Mcl-1, an anti-apoptotic protein, plays an important role in protecting cells from PDT-induced apoptosis. In contrast to the reduction in the anti-apoptotic proteins Bcl-2 and Bcl-xl, sub-lethal PDT induces an increase in Mcl-1 expression. Silencing Mcl-1 sensitizes tumor cells to PDT-induced apoptosis, and ectopic expression of Mcl-1 significantly delays Bax translocation to mitochondria and inhibits caspase-3 activity following PDT. Mcl-1 expression is associated closely with activated AKT signaling following PDT. AKT can regulate Mcl-1 expression through GSK-3β and NF-κB at the protein and transcriptional levels, respectively. Inhibition of AKT by Wortmannin or siRNA significantly reduces the levels of Mcl-1 mRNA and protein and enhances PDT-induced apoptosis. Treatment with Celecoxib, a non-steroidal anti-inflammatory drug (NSAID), is shown to downregulate Mcl-1 expression, and enhances PDT-induced apoptosis both in vitro and in vivo. This down-regulation is closely related to the inhibition effect of Celecoxib on the AKT/GSK-3β pathway, and was blocked upon addition of GSK-3β inhibitor LiCl or the proteasome inhibitor MG132. These results suggest that Mcl-1 is a potential target for improving the antitumor efficiency of PDT. A loss in Mcl-1 by inhibiting AKT promotes PDT-induced apoptosis through the mitochondrial pathway. This also provides a novel rationale for utilizing Celecoxib to improve the efficacy of PDT. © 2013 Elsevier Inc.


Chen L.,Sun Yat Sen University | Chen Y.,South China Normal University
Journal of Scientific Computing | Year: 2011

In this paper, we investigate a scheme for nonlinear reaction-diffusion equations using the mixed finite element methods. To linearize the mixed method equations, we use the two-grid algorithm. First, we solve the original nonlinear equations on the coarse grid, then, we solve the linearized problem on the fine grid used Newton iteration once. It is shown that the algorithm can achieve asymptotically optimal approximation as long as the mesh sizes satisfy H = O(h 1/2 ). As a result, solving such a large class of nonlinear equations will not much more difficult than the solution of one linearized equation. © 2011 Springer Science+Business Media, LLC.


Tang Y.,Xiangtan University | Chen Y.,South China Normal University
Journal of Systems Science and Complexity | Year: 2012

This paper studies variational discretization for the optimal control problem governed by parabolic equations with control constraints. First of all, the authors derive a priori error estimates where {double pipe}{pipe}u - U h{double pipe}{pipe} L∞(J;L2(Ω)) = O(h 2 + k). It is much better than a priori error estimates of standard finite element and backward Euler method where {double pipe}{pipe}u - U h{double pipe}{pipe} L∞(J;L2(Ω)) = O(h + k). Secondly, the authors obtain a posteriori error estimates of residual type. Finally, the authors present some numerical algorithms for the optimal control problem and do some numerical experiments to illustrate their theoretical results. © 2012 Institute of Systems Science, Academy of Mathematics and Systems Science, CAS and Springer-Verlag Berlin Heidelberg.


Tan L.,South China Normal University | Tan L.,U.S. Center for Disease Control and Prevention | Li W.,South China University of Technology | Li H.,South China Normal University | Tang Y.,South China Normal University
Journal of Chromatography A | Year: 2014

Applying molecular imprinting techniques to the surface of functionalized SiO2 allows the preparation of molecularly imprinted polymers (MIPs) with accessible, high affinity and surface exposed binding sites. This paper demonstrates a new strategy for producing such hybrid organic-inorganic surface imprinted silica nanoparticles for specific recognition of methyl parathion. The technique provides surface grafting imprinting in chloroform using amino modified silica nanoparticles as supports, acrylamide as the functional monomer, γ-methacryloxypropyl trimethoxy silane as the grafting agent, and methyl parathion as a template. The amino propyl functional monomer layer directs the selective occurrence of imprinting polymerization at the silica surface through copolymerization of grafting agents with functional monomers, but also acts as an assistive monomer to drive the template into the formed polymer shells to create effective recognition sites. The resulting MIPs-SiO2 nanoparticles display three-dimensional core-shell architectures and large surface areas. The molecularly imprinted shell provides recognition sites for methyl parathion, with the materials exhibiting excellent performance for selecting the template. Using MIPs-SiO2 nanoparticles as a matrix of solid-phase dispersion extraction sorbents, trace amounts of methyl parathion are selectivity extracted from pear and green vegetable samples while simultaneously eliminating matrix interferences, attaining recoveries of 84.7-94.4% for the samples. © 2014 Elsevier B.V.


Li M.,CAS South China Botanical Garden | Li Y.,CAS South China Botanical Garden | Li Y.,Xinjiang University | Li H.,South China Normal University | Wu G.,CAS South China Botanical Garden
Tree Physiology | Year: 2011

Paper mulberry (Broussonetia papyrifera L. Vent) is well known for its bark fibers, which are used for making paper, cloth, rope, etc. It was found that, in addition to its well-documented role in the enhancement of plant salt tolerance, overexpression of the Na+/H+ antiporter (AtNHX5) gene in paper mulberry plants showed high drought tolerance. After exposure to water deficiency and salt stress, the wild-type (WT) plants all died, while the AtNHX5-overexpressing plants remained alive under high salt stress, and had a higher survival rate (>66) under drought stress. Measurements of ion levels indicated that Na+ and K+ contents were all higher in AtNHX5-overexpressing leaves than in WT leaves in high saline conditions. The AtNHX5 plants had higher leaf water content and leaf chlorophyll contents, accumulated more proline and soluble sugars, and had less membrane damage than the WT plants under water deficiency and high saline conditions. Taken together, the results indicate that the AtNHX5 gene could enhance the tolerance of paper mulberry plants to multiple environmental stresses by promoting the accumulation of more effective osmolytes (ions, soluble sugars, proline) to counter the osmotic stress caused by abiotic factors. © The Author 2011. Published by Oxford University Press. All rights reserved.


Li X.,South China Normal University | Hu Z.,CAS Institute of Automation
International Journal of Computer Vision | Year: 2010

A novel method ICF (Identifying point correspondences by Correspondence Function) is proposed for rejecting mismatches from given putative point correspondences. By analyzing the connotation of homography, we introduce a novel concept of correspondence function for two images of a general 3D scene, which captures the relationships between corresponding points by mapping a point in one image to its corresponding point in another. Since the correspondence functions are unknown in real applications, we also study how to estimate them from given putative correspondences, and propose an algorithm IECF (Iteratively Estimate Correspondence Function) based on diagnostic technique and SVM. Then, the proposed ICF method is able to reject the mismatches by checking whether they are consistent with the estimated correspondence functions. Extensive experiments on real images demonstrate the excellent performance of our proposed method. In addition, the ICF is a general method for rejecting mismatches, and it is applicable to images of rigid objects or images of non-rigid objects with unknown deformation. © 2010 Springer Science+Business Media, LLC.


Chen Y.,South China Normal University | Lu Z.,Xiangtan University
Computer Methods in Applied Mechanics and Engineering | Year: 2010

In this paper we study the fully discrete mixed finite element methods for quadratic convex optimal control problem governed by semilinear parabolic equations. The space discretization of the state variable is done using usual mixed finite elements, whereas the time discretization is based on difference methods. The state and the co-state are approximated by the lowest order Raviart-Thomas mixed finite element spaces and the control is approximated by piecewise constant elements. By applying some error estimates techniques of mixed finite element methods, we derive a priori error estimates both for the coupled state and the control approximation. Finally, we present a numerical example which confirms our theoretical results. © 2009.


Chen Y.,South China Normal University | Liu L.,Xiangtan University | Lu Z.,Chongqing Three Gorges University
Numerical Functional Analysis and Optimization | Year: 2010

In this article, we shall give a brief review on the fully discrete mixed finite element method for general optimal control problems governed by parabolic equations. The state and the co-state are approximated by the lowest order Raviart-Thomas mixed finite element spaces and the control is approximated by piecewise constant elements. Furthermore, we derive a posteriori error estimates for the finite element approximation solutions of optimal control problems. Some numerical examples are given to demonstrate our theoretical results. Copyright © Taylor & Francis Group, LLC.


Li D.,Central China Normal University | Li X.,Albany State University | Wang Y.,Jiaying University | Zhao L.,Sichuan Normal University | And 2 more authors.
Journal of Abnormal Child Psychology | Year: 2013

Although a growing body of research documents the negative association between school connectedness and adolescent problematic Internet use (PIU), little is known about the mediating mechanism (i.e.; how school connectedness relates to PIU?) and moderating mechanism (i.e.; when the protection is most potent?) underlying this relation. The present study examined whether deviant peer affiliation mediated the relationship between school connectedness and PIU, and whether this mediating process was moderated by adolescent self-control. A total of 2,758 Chinese adolescents (46 % male; mean age = 13.53 years, SD = 1.06) from 10 middle schools completed anonymous questionnaires regarding school connectedness, deviant peer affiliation, self-control, and PIU. After controlling for gender, age, socioeconomic status, and parental attachment, it was found that the negative association between school connectedness and adolescent PIU was partially mediated by deviant peer affiliation. Moreover, this indirect link was stronger for adolescents with low self-control than for those with high self-control. These findings underscore the importance of integrating the social control theory and organism-environment interaction model to understand how and when school connectedness impacts adolescent PIU. © 2013 Springer Science+Business Media New York.


Bao B.,Biocontrol | Hong B.,Biocontrol | Feng Q.-L.,South China Normal University | Xu W.-H.,Biocontrol
Insect Biochemistry and Molecular Biology | Year: 2011

The transcription factor fork head (FoxA) plays important roles in development and metabolism. Here, we cloned a fork head gene in Helicoverpa armigera, and found that the fork head protein is mainly located in the nucleus. This fork head gene belongs to the FoxA subfamily of the Fox transcription factors. The diapause hormone and pheromone biosynthesis-activating neuropeptide (DH-PBAN), which are two well-documented insect neuropeptides that regulate insect development and pheromone biosynthesis, are encoded by a single mRNA. In the present study, fork head was shown to bind strongly to the promoter of H. armigera DH-PBAN gene, and regulate its promoter activity. Furthermore, the effect of SUMOylation of the FH protein on the regulation of Har-DH-PBAN gene was investigated, and we show that the SUMO can modify Har-FH protein and cause down-regulation of DH-PBAN gene expression. These results suggest that SUMOylated FH plays a key role in insect diapause in H. armigera. © 2011 Elsevier Ltd.


Yang H.H.,State University of New York at Oswego | Chen P.,South China Normal University
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2010

Integrating technology in K-12 classroom is a complex challenge for teachers. This article provides an overview on the conceptualization of Technological Pedagogical Content Knowledge (TPACK), project-based learning and WebQuests, and blended learning. It presents how an instructional approach which incorporated WebQuest development and blended learning process is implemented into one educational technology course at a university in the northeastern region of the United States. The effectiveness of such an instructional approach on TPACK among participants of the course has been confirmed in this study. Discussion and conclusion of building a stronger pre- and in-service teachers' TPACK for educational technology courses are included. © Springer-Verlag 2010.


Tan L.,U.S. Center for Disease Control and Prevention | Huang C.,U.S. Center for Disease Control and Prevention | Peng R.,U.S. Center for Disease Control and Prevention | Tang Y.,South China Normal University | Li W.,South China University of Technology
Biosensors and Bioelectronics | Year: 2014

Applying molecular imprinting techniques to the surface of functionalized quantum dots (QDs) allows the preparation of molecularly imprinted polymers (MIPs) with accessible, surface exposed binding sites and excellent optical properties. This paper demonstrates a new strategy for producing such hybrid organic-inorganic imprinted Mn-doped ZnS QDs for specific recognition of bovine hemoglobin. The technique provides surface grafting imprinting in aqueous solutions using amino modified Mn-doped ZnS QDs as supports, acrylamide and methacrylic acid as functional monomers, γ-methacryloxypropyl trimethoxy silane as the grafting agent, and bovine hemoglobin as a template. The amino propyl functional monomer layer directs the selective occurrence of imprinting polymerization at the QDs surface through copolymerization of grafting agents with functional monomers, but also acts as an assistive monomer to drive the template into the formed polymer shells to create effective recognition sites. Using MIP-QDs composites as a fluorescence sensing material, trace amounts of bovine hemoglobin are signaled with high selectivity by emission intensity changes of Mn-doped ZnS QDs, which is embedded into the imprinted polymers. © 2014 Elsevier B.V.


Deng P.Y.,South China Normal University | Liu W.,Pearl River Water Environment Monitoring Center | Zeng B.Q.,The Hong Kong Institute of Education | Qiu Y.K.,South China Normal University | Li L.S.,South China Normal University
International Journal of Environmental Science and Technology | Year: 2013

Ruppia maritima and Echinodorus amazonicus were prepared in a dehydrated powder form. The characteristics and mechanisms of adsorption of heavy metals were studied under various pH values, reaction times, and heavy metal ion concentrations. The results showed that under different pH and reaction time conditions, heavy metal adsorption was lead > cadmium > zinc > copper. The adsorption of lead increased linearly with the lead concentration. For cadmium, zinc and copper, the adsorption was saturated when metal ion concentration exceeded 200 mg/L. When a Freundlich model was applied, R2 values for the heavy metal adsorption by the aquatic plants mostly exceeded 0. 9. The adsorption of heavy metal ions by these two aquatic plant powders was better explained by the Lagergren second-order equation than the first-order equation. From the Fourier Transform Infrared spectra, there was an adsorption peak at 2,115 cm-1 for R. maritima. The peak shape did not change with metal affiliation except there was a shift of peak wavelength before adsorption. The results indicate that the mechanism of heavy metal adsorption by the two species is not simply on the mono-molecular layer level, and that intra-particulate dispersal is the dominant process. Heavy metal pollution does not affect the basic chemical components, and major substances involved in heavy metal adsorption including carbohydrates, cell wall pectin, and protein functional groups. © 2013 Islamic Azad University (IAU).


Zou P.,South China Normal University | Zhang Z.-M.,South China Normal University | Song W.,Hefei Normal University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

The direct state measurement (DSM) based on the weak measurement has the advantage of simplicity, versatility, and directness. However, the weak measurement will introduce an unavoidable error in the reconstructed quantum state. We modify the DSM by replacing the weak coupling between the system and the pointer by a strong one, and present two procedures for measuring quantum states, one of which can give the wave function or the density matrix directly. We can also measure the Dirac distribution of a discrete system directly. Furthermore, we propose quantum circuits for realizing these procedures, and the main body of the circuits consists of Toffoli gates. By numerical simulation, we find that our scheme can eliminate the biased error effectively. ©2015 American Physical Society.


Yang Y.,Xiangtan University | Chen Y.,South China Normal University | Huang Y.,Xiangtan University
Acta Mathematica Scientia | Year: 2014

We propose and analyze a spectral Jacobi-collocation approximation for fractional order integro-differential equations of Volterra type. The fractional derivative is described in the Caputo sense. We provide a rigorous error analysis for the collection method, which shows that the errors of the approximate solution decay exponentially in L∞ norm and weighted L2-norm. The numerical examples are given to illustrate the theoretical results. © 2014 Wuhan Institute of Physics and Mathematics.


Chen Y.,South China Normal University | Lu Z.,Chongqing Three Gorges University | Lu Z.,Xiangtan University | Huang Y.,Xiangtan University
Computers and Mathematics with Applications | Year: 2013

In this paper, we analyze the superconvergence of the bilinear constrained elliptic optimal control problem by triangular Raviart-Thomas mixed finite element methods. The state and the co-state are approximated by the order k=1 Raviart-Thomas mixed finite elements and the control is approximated by piecewise constant functions. We obtain the superconvergence property between average L2 projection and the approximation of the control variable, and the convergence order is h2. Two numerical examples are presented for illustrating the superconvergence results. © 2013 Elsevier Ltd. All rights reserved.


Zhan Q.,Zhejiang University | Zhan Q.,South China Normal University | Qian J.,Zhejiang University | Liang H.,Harbin Institute of Technology | And 7 more authors.
ACS Nano | Year: 2011

Successful further development of superhigh-constrast upconversion (UC) bioimaging requires addressing the existing paradox: 980 nm laser light is used to excite upconversion nanoparticles (UCNPs), while 980 nm light has strong optical absorption of water and biological specimens. The overheating caused by 980 nm excitation laser light in UC bioimaging is computationally and experimentally investigated for the first time. A new promising excitation approach for better near-infrared to near-infrared (NIR-to-NIR) UC photoluminescence in vitro or in vivo imaging is proposed employing a cost-effective 915 nm laser. This novel laser excitation method provides drastically less heating of the biological specimen and larger imaging depth in the animals or tissues due to quite low water absorption. Experimentally obtained thermal-graphic maps of the mouse in response to the laser heating are investigated to demonstrate the less heating advantage of the 915 nm laser. Our tissue phantom experiments and simulations verified that the 915 nm laser is superior to the 980 nm laser for deep tissue imaging. A novel and facile strategy for surface functionalization is utilized to render UCNPs hydrophilic, stable, and cell targeting. These asprepared UCNPs were characterized by TEM, emission spectroscopy, XRD, FTIR, and zeta potential. Specifically targeting UCNPs excited with a 915 nm laser have shown very high contrast UC bioimaging. Highly stable DSPE-mPEG-5000-encapsulated UCNPs were injected into mice to perform in vivo imaging. Imaging and spectroscopy analysis of UC photoluminescence demonstrated that a 915 nm laser can serve as a new promising excitation light for UC animal imaging. © 2011 American Chemical Society.


Bao Z.,South China Normal University | Li D.,Central China Normal University | Zhang W.,South China Normal University | Wang Y.,Jiaying University
Journal of Abnormal Child Psychology | Year: 2015

School climate is the quality and character of school life and reflects the norms, goals, values, interpersonal relationships, teaching and learning practices, and the organizational structure of a school. There is substantial literature documenting the negative association between positive school climate and adolescent delinquency, but little is known about the moderating and mediating mechanisms underlying this relationship. The aim of this study was to examine whether the direct and indirect pathways between school climate and adolescent delinquency would be moderated by effortful control. A sample of 2,758 Chinese adolescents (M age = 13.53 years, SD = 1.06) from 10 middle schools completed anonymous questionnaires regarding school climate, effortful control, deviant peer affiliation, and delinquency. After gender, age, geographical area, and socioeconomic status were included as covariates, the results revealed that school climate was significantly associated with adolescent delinquent behavior. This direct association was moderated by effortful control, such that the negative relationship between positive school climate and delinquency was only significant among adolescents low in effortful control. Moreover, the indirect association between school climate and delinquency via deviant peer affiliation was also moderated by effortful control. Specifically, the moderating effect of effortful control was not only manifested in the relationship between school climate and deviant peer affiliation, but also in the relationship between deviant peer affiliation and delinquency. These findings contribute to understanding the mechanisms through which positive school climate might reduce delinquent behavior and have important implications for prevention efforts aimed at diminishing adolescent delinquency. © 2014, Springer Science+Business Media New York.


Ai B.-Q.,South China Normal University | Ai B.-Q.,Hong Kong Baptist University | Hu B.,Hong Kong Baptist University | Hu B.,University of Houston
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

Heat conduction through the Frenkel-Kontorova lattices is numerically investigated in the presence of a deformable substrate potential. It is found that the deformation of the substrate potential has a strong influence on heat conduction. The thermal conductivity as a function of the shape parameter is nonmonotonic. The deformation can enhance thermal conductivity greatly, and there exists an optimal deformable value at which thermal conductivity takes its maximum. Remarkably, we also find that the deformation can facilitate the appearance of the negative differential thermal resistance. © 2011 American Physical Society.


Ai B.-Q.,South China Normal University | Zhong W.-R.,Jinan University | Hu B.,Hong Kong Baptist University | Hu B.,University of Houston
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

We study heat conduction through one-dimensional homogeneous lattices in the presence of the nonlinear on-site potentials containing the bounded and unbounded parts, and the harmonic interaction potential. We observe the occurrence of double negative differential thermal resistance (NDTR); namely, there exist two regions of temperature difference, where the heat flux decreases as the applied temperature difference increases. The nonlinearity of the bounded part contributes to NDTR at low temperatures and NDTR at high temperatures is induced by the nonlinearity of the unbounded part. The nonlinearity of the on-site potentials is necessary to obtain NDTR for the harmonic interaction homogeneous lattices. However, for the anharmonic homogeneous lattices, NDTR even occurs in the absence of the on-site potentials, for example, the rotator model. © 2011 American Physical Society.


Kang C.,South China Normal University | Li W.,Technical Service Center Laboratory of Panyu Entry Exit Inspection and Quarantine Bureau | Tan L.,South China Normal University | Li H.,South China Normal University | And 2 more authors.
Journal of Materials Chemistry A | Year: 2013

We prepared highly ordered metal ion imprinted mesoporous silica (IIMS) through co-condensation using a combination of molecular imprinting technology and traditional mesoporous materials. Copper ion is used as the template. Besides the periodic hexagonal structure, nano-sized wall thickness, and large surface area, it is found that the IIMS has highly specific recognition ability for the template. The imprinting factor of IIMS exhibits a maximum value of 3.7 at pH 2.5. The material shows fast binding kinetics for Cu2+ (complete equilibrium reach only within 5 min) and the saturation adsorption capacity reaches up to 0.39 mmol g-1. Homogeneous binding sites are confirmed by the Langmuir isothermal model and the Langmuir-Freundlich isothermal model. The heterogeneity index is 0.992 with a value similar to those found for molecularly imprinted polymers prepared using covalent imprinting. The recovery of the silica stays above 90% after six extraction-stripping cycles. Furthermore, the silica has significant potential for water treatment applications. This journal is © The Royal Society of Chemistry 2013.


Xing L.,University of Utah | Xing L.,South China Normal University | Borodin O.,U.S. Army
Physical Chemistry Chemical Physics | Year: 2012

The oxidation induced reactions of the common lithium battery electrolyte solvent ethylene carbonate (EC) have been investigated for EC 2 using density functional theory and for selected reaction paths using Moller-Plesset perturbation theory (MP4). The importance of explicitly treating at least one solvent molecule interacting with EC during oxidation (removal of an electron) on the EC oxidation potential and decomposition reactions was shown by comparing oxidation of EC and EC 2. Accuracy of DFT results was evaluated by comparing with MP4 and G4 values for oxidation of EC. The polarized continuum model (PCM) was used to implicitly include the rest of the surrounding solvent. The oxidation potentials of EC 2 and EC 4 were found to be significantly lower than the intrinsic oxidation potential of an isolated EC and also lower than the oxidation potential of EC-BF 4 -. The exothermic proton abstraction from the ethylene group of EC by the carbonyl group of another EC was responsible for the decreased oxidative stability of EC 2 and EC 4 compared to EC. The most exothermic path with the smallest barrier for EC 2 oxidation yielded CO 2 and an ethanol radical cation. The reaction paths with the higher barrier yielded oligo(ethylene carbonate) suggesting a pathway for the experimentally observed poly(ethylene carbonate) formation of EC-based electrolytes at cathode surfaces. © 2012 the Owner Societies.


Xing L.,University of Utah | Xing L.,South China Normal University | Vatamanu J.,University of Utah | Borodin O.,U.S. Army | And 2 more authors.
Journal of Physical Chemistry C | Year: 2012

The double layer composition and structure of the mixed-solvent electrolyte tetramethylene sulfone/dimethyl carbonate (TMS/DMC) doped with LiPF6 near the graphite surface have been investigated using molecular dynamics simulations as a function of applied potential between the electrodes ranging from 0 to 6 V. Three solvent compositions, with TMS/DMC ratios of 1:2, 1:1, and 2:1 doped with LiPF6 salt, were investigated. At uncharged electrodes, electrolyte composition at the interfaces was found to be similar to that of bulk electrolyte for TMS/DMC ratios of 1:1 and 1:2 systems but deviated from the bulk for a TMS/DMC ratio of 2:1. At negative electrodes the polar solvent TMS preferentially adsorbs at the electrode surface displacing the almost nonpolar DMC solvent. The preferential partitioning of TMS relative to DMC to the negative electrode surface is consistent with the stronger binding of the former with Li+ that partitions to the anode surface as potential becomes more negative as well as with the ability of relatively polar TMS to better respond to the electrostatic potential near a charged surface. At the positive electrode, TMS/DMC ratios were found to be similar to bulk compositions that is different to the behavior observed in ethylene carbonate (EC)/DMC/LiPF6 electrolyte where preferential partitioning of a more polar EC molecule was observed on both electrodes. Our results also show that, in TMS/DMC/LiPF6 electrolyte, DMC is located approximately 0.8 Å further way from the positive electrode than in EC/DMC/LiPF6 indicating that it might be more difficult to oxidize DMC in the TMS-based electrolytes that is consistent with experimentally reported increased oxidative stability of the latter. Finally, changes of the Li+ solvation shell and double layer capacitance were analyzed as a function of electrode potential. © 2012 American Chemical Society.


Xing L.,University of Utah | Xing L.,South China Normal University | Vatamanu J.,University of Utah | Borodin O.,U.S. Army | Bedrov D.,University of Utah
Journal of Physical Chemistry Letters | Year: 2013

The capacitance enhancement experimentally observed in electrodes with complex morphology of random subnanometer wide pores is an intriguing phenomena, yet the mechanisms for such enhancement are not completely understood. Our atomistic molecular dynamics simulations demonstrate that in subnanometer slit-geometry nanopores, a factor of 2 capacitance enhancement (compared to a flat electrode) is possible for the 1-ethyl-3-methylimidazolium (EMIM)-bis(trifluoro-methylsulfonyl)imide (TFSI) ionic liquid electrolyte. This capacitance enhancement is a result of a fast charge separation inside the nanopore due to abrupt expulsion of co-ions from the pore while maintaining an elevated counterion density due to strong screening of electrostatic repulsive interactions by the conductive pore. Importantly, we find that the capacitance enhancement can be very asymmetric. For the negatively charged 7.5 Å wide pore, the integral capacitance is 100% larger than on a flat surface; however, on the positive electrode, almost no enhancement is observed. Detailed analysis of structure and composition of electrolyte inside nanopores shows that the capacitance enhancement and the shape of differential capacitance strongly depend on the details of the ion chemical structure and a delicate balance of ion-surface and ion-ion interactions. © 2012 American Chemical Society.


Li X.,South China Normal University | Wu J.,University of Electronic Science and Technology of China | Wang Z.M.,University of Electronic Science and Technology of China | Wang Z.M.,University of Arkansas | And 4 more authors.
Nanoscale | Year: 2014

Creating and manipulating materials at the nanoscale with controllable size, shape and nucleation site is an important task to meet the urgent demands for quantum structures with designed properties. In the last ten years, droplet epitaxy has been emerging as a versatile fabrication method for various complex nanostructures, such as quantum dots, quantum rings, double-rings, and so on. However, there is a lack of understanding of the deep nanohole formation based on droplet epitaxy at a high substrate temperature. Here we fabricate self-organized GaAs nanoholes by Ga droplet etching at high temperature based on droplet epitaxy, and they present good optoelectronic properties and have promising applications in fabrication of nanodevices due to their unique topology. A theoretical model is correspondingly proposed to explain the basic mechanism and simulate the time evolution of the nanohole structures. Our analysis shows that the morphology of the nanohole nanostructures can be well controlled through regulating experimental conditions. © 2014 The Royal Society of Chemistry.


Wang X.-D.,South China Normal University | Wang X.-D.,Huaibei Normal University | Luo Z.-C.,South China Normal University | Liu H.,South China Normal University | And 3 more authors.
Applied Physics Letters | Year: 2014

We reported on the femtosecond pulse generation from an erbium-doped fiber (EDF) laser by using microfiber-based gold nanorods (GNRs) as saturable absorber (SA). By virtue of the geometric characteristic of microfiber-based GNRs, the optical damage threshold of GNRs-SA could be greatly enhanced. The microfiber-based GNRs-SA shows a modulation depth of 4.9% and a nonsaturable loss of 21.1%. With the proposed GNRs-SA, the fiber laser emitted a mode-locked pulse train with duration of ∼887 fs. The obtained results demonstrated that the GNRs deposited microfiber could indeed serve as a high-performance SA towards the practical applications in the field of ultrafast photonics. © 2014 AIP Publishing LLC.


Chen X.,South China Normal University | Chen X.,Shanghai Normal University | Zhang H.,Shanghai Normal University | Ruan K.,Fujian Agriculture and forestry University | Shi W.,Shanghai Normal University
Journal of Alloys and Compounds | Year: 2012

We reported the annealing effect on the electrical behaviors of BiFeO 3 thin films integrated on LaNiO 3 (LNO) layers buffered Si substrates by sol-gel spin-coating technique. All the BiFeO 3 thin films exhibit the reversible bipolar resistive switching behaviors with Pt/BiFeO 3/LNO configuration. The electrical conduction mechanism of the devices was dominated by the Ohmic conduction in the low resistance state and trap-controlled space charged limited current in the high resistance state. Good diode-like rectification property was observed in device with BiFeO 3 film annealed at 500 °C, but vanished in device with BiFeO 3 film annealed at 600 °C. This was attributed to the asymmetrical contact between top and bottom interfaces as well as the distinct oxygen vacancy density verified by XPS. Furthermore, the modification of Schottky-like barrier due to the drift of oxygen vacancies was suggested to be responsible for the resistance switching behaviors of Pt/BiFeO 3/LNO devices. © 2012 Elsevier B.V. All rights reserved.


Ai B.-Q.,South China Normal University | He Y.-F.,Hebei University
Journal of Chemical Physics | Year: 2010

Transport of the Brownian particles driven by Ĺvy flights coexisting with subdiffusion in asymmetric periodic potentials is investigated in the absence of any external driving forces. Using the Langevin-type dynamics with subordination techniques, we obtain the group velocity which can measure the transport. It is found that the group velocity increases monotonically with the subdiffusive index and there exists an optimal value of the Ĺvy index at which the group velocity takes its maximal value. There is a threshold value of the subdiffusive index below which the ratchet effects will disappear. The nonthermal character of the Ĺvy flights and the asymmetry of the potential are necessary to obtain the directed transport. Some peculiar phenomena induced by the competition between Ĺvy flights and subdiffusion are also observed. The pseudonormal diffusion will appear on the level of the median. © 2010 American Institute of Physics.


Zhang Y.,South China Normal University | Zhang Y.,Hong Kong Baptist University | Wong J.W.C.,Hong Kong Baptist University | Liu P.,South China Normal University | Yuan M.,South China Normal University
Journal of Hazardous Materials | Year: 2011

Photocatalytic degradation of phenanthrene (PHE) over TiO2 in aqueous solution containing nonionic surfactant micelles was investigated. All photocatalytic experiments were conducted using a 253.7nm mercury monochromatic ultraviolet lamp in a photocatalytic reactor. The surfactant micelles could provide a nonaqueous " cage" to result in a higher degradation rate of PHE than in an aqueous solution, but the higher Triton X-100 concentration (more than 2g/L) lowered the degradation ratio of PHE because the additional surfactant micelles hindered the movement of micelles containing PHE so as to reduce their adsorption onto titania. Pseudo-second-order kinetics was observed for the photocatalytic degradation of PHE. Alkaline solution environment was beneficial to the photocatalytic degradation of PHE. PHE degradation could mainly be attributed to the formation of hydroxyl radicals as evident from the comparison of degradation efficiencies when O2, H2O2 and tert-butyl alcohol (TBA) were applied as oxidants or hydroxyl radical scavenger. Based on the GC/MS analysis of the intermediates, the possible pathways of the photocatalytic degradation of PHE were proposed. © 2011 Elsevier B.V.


Li J.,South China Normal University | Choo-Smith L.-P.,National Research Council Canada | Tang Z.,South China Normal University | Sowa M.G.,National Research Council Canada
Journal of Raman Spectroscopy | Year: 2011

A wavelet transformation method is introduced to remove the large fluorescence background from polarized Raman spectra of stained tooth enamel. This method exploits the wavelet multiresolution decomposition where the experimental Raman spectrum is decomposed into signals with different frequency components, and where the lowest frequency background and highest frequency noise are removed. This method is optimized using a simulated collection of parallel-polarized and cross-polarized Raman spectra of the enamel and then applied to a set of experimental data. The results show that the wavelet transform technique can extract the pure spectra from background and noise, with the depolarization ratio used to discriminate between early dental caries and sound enamel preserved. A wavelet transformation method is used to remove the large fluorescence background from polarized Raman spectra of stained tooth enamel. The results show that the wavelet transform technique could extract the pure spectra from background and noise, with the Raman depolarization ratio used to discriminate early dental caries and sound enamel preserved. Copyright © 2010 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.


Lin J.,South China Normal University | Wang Q.,South China Normal University | Wang Q.,Guangzhou Key Laboratory of Materials for Energy Conversion and Storage
Chemical Engineering Journal | Year: 2014

The concept of "slow release anions for the assembly of crystals" was successfully carried out through a facile, effective and environmental friendly supersonic and microwave co-assistance (SMC) approach at very low temperature in less than 40min. It has been found that the rational design of multiple irradiations, lanthanide contraction and fluoride sources would make it possible to control both the crystalline phases (hexagonal or orthorhombic) and the microstructures (including nanoparticles, nanoplates or micro-meter scale particles). The photo-luminescent properties of EuF3 and TbF3 revealed that characteristic red and green emissions can be excited by multiple wavelengths. Moreover, the results demonstrated that there are efficient energy transfers from Gd3+ to Eu3+ and Tb3+ in GdF3: Eu3+ and GdF3: Tb3+ phosphors based on this new method. © 2014 Elsevier B.V.


Zhang Y.,South China Normal University | Han C.,University of Cincinnati | Nadagouda M.N.,JKK Nataraja Dental College and Hospital | Dionysiou D.D.,University of Cincinnati | Dionysiou D.D.,University of Cyprus
Applied Catalysis B: Environmental | Year: 2015

N,F-codoped TiO2 nanowires were synthesized using titanium sulfate as a Ti precursor and isopropanol as a protective capping agent by a hydrothermal route. The obtained doped nanowires were characterized by XRD, SEM, TEM, HRTEM, SAED, XPS, porosimetry analysis and UV-vis diffuse reflectance spectroscopy. The synthesized N,F-codoped TiO2 nanowires calcined at 500°C have TiO2 (B) and anatase phase and then are completely transformed to anatase phase after calcination at 600°C. Photocatalytic activity measurements show that the N,F-codoped TiO2 nanowires calcined at 600°C possess the best photocatalytic performance for the degradation of atrazine under UV and visible light irradiation in comparison with N,F-codoped TiO2 nanoparticles and N-doped TiO2 nanowires, which was attributed to the relatively more quantity of active {001} crystal facet due to the addition of F- and the synergistic effect of N and F doping. © 2015 Elsevier B.V.


Zhou Z.,South China Normal University | Wang Q.,South China Normal University | Wang Q.,Guangzhou Key Laboratory of Materials for Energy Conversion and Storage
Nanoscale | Year: 2014

A novel organic-inorganic hybrid sensor based on diethylenetriaminepentaacetic acid (DTPA) modified reduced graphene oxide (RGO-DTPA) chelated with terbium ions allows detection of dopamine (DA) through an emission enhancement effect. Its luminescence, peaking at 545 nm, has been improved by a factor of 25 in the presence of DA (detection limit = 80 nM). In addition, this covalently bonded terbium complex functionalized reduced graphene oxide (RGO-DTPA-Tb) can be successfully assembled on a glassy carbon electrode. The assay performed through differential pulse voltammetry (DPV) yielded obvious peak separation between DA and excessive amounts of the interfering ascorbic acid (AA). © 2014 the Partner Organisations.


Li X.-Q.,Guangzhou Sport University | Xu Y.,South China Normal University
Optics Communications | Year: 2013

We demonstrate that Photonic Crystal (PhC) based Mach-Zehnder interferometers (MZIs) can be used to realize optical biosensor by using the Fano resonance of the MZIs. Small analyte presented in the MZIs would, however, excite higher-Q Fano resonance of the system than the big one. The scattering object in the arm would create a resonant path (discrete state) for the MZIs, which interacts with the input broadband continuum spectrum and thus results in the Fano resonance of the system. We can therefore detect the location, size and refractive index of biological analyte (down to approximately 100 nm in size) in the MZIs via the output transmission spectrum. An analytical model, which outlines the sensing mechanism, is presented together with the finite difference time domain computer simulations. Both of them validate the proposed sensing capacity. © 2013 Elsevier B.V.


Ai B.-Q.,South China Normal University | He Y.-F.,Hebei University | Zhong W.-R.,Jinan University
Soft Matter | Year: 2015

Dynamics and separation of mixed chiral microswimmers are numerically investigated in a channel with regular arrays of rigid half-circle obstacles. For zero shear flow, transport behaviors are the same for different chiral particles: the average velocity decreases with increase of the rotational diffusion coefficient, the direction of the transport can be reversed by tuning the angular velocity, and there exists an optimal value of the packing fraction at which the average velocity takes its maximal value. However, when the shear flow is considered, different chiral particles show different behaviors. By suitably tailoring parameters, particles with different chiralities can move in different directions and can be separated. In addition, we also proposed a space separation method by introducing a constant load, where counterclockwise and clockwise particles stay in different regions of the channel. © The Royal Society of Chemistry 2015.


Wang F.,South China Normal University | Ouyang G.,Hong Kong Baptist University | Zhou C.,Hong Kong Baptist University | Wang S.,South China Normal University
PLoS ONE | Year: 2015

A number of studies have explored the time course of Chinese semantic and syntactic processing. However, whether syntactic processing occurs earlier than semantics during Chinese sentence reading is still under debate. To further explore this issue, an event-related potentials (ERPs) experiment was conducted on 21 native Chinese speakers who read individually-presented Chinese simple sentences (NP1+VP+NP2) word-by-word for comprehension and made semantic plausibility judgments. The transitivity of the verbs was manipulated to form three types of stimuli: congruent sentences (CON), sentences with a semantically violated NP2 following a transitive verb (semantic violation, SEM), and sentences with a semantically violated NP2 following an intransitive verb (combined semantic and syntactic violation, SEM+SYN). The ERPs evoked from the target NP2 were analyzed by using the Residue Iteration Decomposition (RIDE) method to reconstruct the ERP waveform blurred by trial-to-trial variability, as well as by using the conventional ERP method based on stimulus-locked averaging. The conventional ERP analysis showed that, compared with the critical words in CON, those in SEM and SEM+SYN elicited an N400-P600 biphasic pattern. The N400 effects in both violation conditions were of similar size and distribution, but the P600 in SEM+SYN was bigger than that in SEM. Compared with the conventional ERP analysis, RIDE analysis revealed a larger N400 effect and an earlier P600 effect (in the time window of 500-800 ms instead of 570-810ms). Overall, the combination of conventional ERP analysis and the RIDE method for compensating for trial-to-trial variability confirmed the non-significant difference between SEM and SEM+SYN in the earlier N400 time window. Converging with previous findings on other Chinese structures, the currentstudy provides further precise evidence that syntactic processing in Chinese does not occur earlier than semantic processing. © 2015 Wang et al.


Zhang T.,Hong Kong Baptist University | Zhang T.,South China Normal University | Lan R.,Hong Kong Baptist University | Chan C.-F.,Hong Kong Baptist University | And 3 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014

In this work, we demonstrate a modality of photodynamic therapy (PDT) through the design of our truly dual-functional - PDT and imaging - gadolinium complex (Gd-N), which can target cancer cells specifically. In the light of our design, the PDT drug can specifically localize on the anionic cell membrane of cancer cells in which its laser-excited photoemission signal can be monitored without triggering the phototoxic generation of reactive oxygen species - singlet oxygen - before due excitation. Comprehensive in vitro and in vivo studies had been conducted for the substantiation of the effectiveness of Gd-N as such a tumor-selective PDT photosensitizer. This treatment modality does initiate a new direction in the development of "precision medicine" in line with stem cell and gene therapies as tools in cancer therapy. © 2014, National Academy of Sciences. All rights reserved.


Zhang T.,Hong Kong Baptist University | Zhang T.,South China Normal University | Chan C.-F.,Hong Kong Baptist University | Lan R.,Hong Kong Baptist University | And 2 more authors.
Chemistry - A European Journal | Year: 2014

A new lanthanide probe based on the fluorescence resonance energy transfer (FRET) process with the combination of ytterbium porphyrinate complex and a rhodamine B derivative unit was synthesized to detect the Hg2+ ion with responsive emission in the visible and near-IR region with a detection limit of 10 μM Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Ai B.-Q.,South China Normal University | He Y.-F.,Hebei University | Zhong W.-R.,Jinan University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

Transport of Brownian particles interacting with each other via the Morse potential is investigated in the presence of an ac driving force applied locally at one end of the chain. By using numerical simulations, we find that the system can behave as a particle diode for both overdamped and underdamped cases. For low frequencies, the transport from the free end to the ac acting end is prohibited, while the transport from the ac acting end to the free end is permitted. However, the polarity of the particle diode will reverse for medium frequencies. There exists an optimal value of the well depth of the interaction potential at which the average velocity takes its maximum. The average velocity υ decreases monotonically with the system size N by a power law υN-1. © 2011 American Physical Society.


He Y.-F.,Hebei University | Ai B.-Q.,South China Normal University | Liu F.-C.,Hebei University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

We study the interaction of both dense and sparse multiarmed spirals in bistable media modeled by equations of the FitzHugh-Nagumo type. A dense one-armed spiral is characterized by its fixed tip. For dense multiarmed spirals, when the initial distance between tips is less than a critical value, the arms collide, connect, and disconnect continuously as the spirals rotate. The continuous reconstruction between the front and the back drives the tips to corotate along a rough circle and to meander zigzaggedly. The rotation frequency of tip, the frequency of zigzagged displacement, the frequency of spiral, the oscillation frequency of media, and the number of arms satisfy certain relations as long as the control parameters of the model are fixed. When the initial distance between tips is larger than the critical value, the behaviors of individual arms within either dense or sparse multiarmed spirals are identical to that of corresponding one-armed spirals. © 2013 American Physical Society.


Ai B.-Q.,South China Normal University | Chen Q.-Y.,South China Normal University | He Y.-F.,Hebei University | Li F.-G.,South China Normal University | Zhong W.-R.,Jinan University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

Rectification and diffusion of noninteracting self-propelled particles is numerically investigated in a two-dimensional corrugated channel. From numerical simulations, we obtain the average velocity and the effective diffusion coefficient. It is found that the self-propelled particles can be rectified by the self-propelled velocity. There exist optimal values of the parameters (the self-propelled velocity, the translational diffusion constant, and the height of the potential) at which the average velocity takes its maximal value. There exists an optimal translational diffusion at which the effective diffusion constant is maximal. The self-propelled velocity can strongly increase the effective diffusion, while the large rotational diffusion rate can strongly suppress the effective diffusion. © 2013 American Physical Society.


Deng D.,South China Normal University | Deng D.,University of Chinese Academy of Sciences | Chen C.,South China Normal University | Zhao X.,Taishan Medical University | And 3 more authors.
Optics Letters | Year: 2014

A virtual source that yields a family of a Pearcey wave is demonstrated. A closed-form expression is derived for the Pearcey wave that simplifies to the paraxial Pearcey beam (PB) in the appropriate limit. From the perturbative series representation of a complex-source-point spherical wave, an infinite series nonparaxial correction expression for a PB is obtained. The infinite series expression of a PB can give accuracy up to any order of the diffraction angle. By applying the integral representation of the Pearcey wave, the first three terms in the nonparaxial correction series to the paraxial PB are provided. © 2014 Optical Society of America.


Lin J.,South China Normal University | Zhou Z.,South China Normal University | Wang Q.,South China Normal University | Wang Q.,Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System
Materials Research Bulletin | Year: 2013

GdNbO4:Eu3+ and LuTaO4:Eu3+ have been successfully prepared with different fluxes (NaCl, KCl, NaCl and KCl) by the molten salt method. X-ray diffraction (XRD) patterns illustrated that well crystallized GdNbO4:Eu3+ and LuTaO 4:Eu3+ in the presence of fluxes were formed under reduced temperature (900 C) in contrast to conventional method (GdNbO 4:Eu3+: around 1200 C; LuTaO4:Eu3+: around 1500 C). Scanning electron microscope (SEM) images revealed that well dispersed particles were achieved (granular or rod-like structures). Meanwhile, the photo-luminescent studies demonstrated that both niobate and tantalate are efficient hosts to sensitize europium red emissions. The results indicated that GdNbO4:Eu3+ using NaCl as the flux gave much enhanced red emission whereas LuTaO4:Eu3+ synthesized with the assistance of mixed salts (NaCl-KCl) achieved the best luminescence. © 2013 Elsevier Ltd. All rights reserved.


Huang Y.,CAS Guangzhou Institute of Geochemistry | Huang Y.,University of Chinese Academy of Sciences | Luo J.,South China Normal University | Xia B.,CAS Guangzhou Institute of Geochemistry
Journal of Cleaner Production | Year: 2013

As the largest output and export province of ceramic tiles in China, Guangdong has been faced with the contradictory problem that the ceramic tile industry brings both huge economic benefits and adverse environmental impacts. To promote energy conservation and emission reduction in the ceramic tile industry, the activity of "Cleaner Production Auditing for a Thousand Voluntary Industrial Enterprises" has been held since 2010 in Guangdong. This study presents a comprehensive application of cleaner production in a typical medium-scale ceramic tile plant, which has initially taken part in the cleaner production activity. On the basis of pre-auditing conducted in the selected plant, key auditing procedures and main objectives were determined. After the analysis of material balance and energy efficiency in key auditing procedures, 31 different measures, including facility replacement, technology improvement, process control, raw material and waste reutilization, plant management, and worker training, have been proposed and implemented in a feasible way. Through the cleaner production application, the plant achieved the expected objectives and obtained obvious progress in energy conservation and emission reduction. For each unit product, the consumption of energy and water were cut down by 4.3% and 22.33%, respectively. The SO2 emission per unit product was also reduced by 8% after the cleaner production. Although the cleaner production is a continuous process in this case, it provides a theoretical and practical basis for the sustainable development of other ceramic tile production enterprises. © 2012 Elsevier Ltd. All rights reserved.


Zhang D.D.,University of Hong Kong | Lee H.F.,University of Hong Kong | Wang C.,Jinan University | Li B.,South China Normal University | And 3 more authors.
Global Ecology and Biogeography | Year: 2011

Aim It has long been assumed that deteriorating climate (cooling and warming above the norm) could shrink the carrying capacity of agrarian lands, depriving the human population of sufficient food. Population collapses (i.e. negative population growth) follow. However, this human-ecological relationship has rarely been verified scientifically, and evidence of warming-caused disaster has never been found. This research sought to explore quantitatively the temporal pattern, spatial pattern and triggers of population collapses in relation to climate change at the global scale over 1100 years. Location Various countries/regions in the Northern Hemisphere (NH) during the pre-industrial era. Methods We performed time-series analysis to examine the association between temperature change and country-wide/region-wide population collapses in different climatic zones. All of the known population collapse incidents in the NH in the period ce 800-1900 were included in our data analysis. Results Nearly 90% of population collapses in various NH countries/regions occurred during periods of climate deterioration characterized by shrinking carrying capacity of the land. In addition, we found that cooling dampened the human ecosystem and brought about 80% of the collapses in warmer humid, cooler humid and dry zones, while warming adversely affected the ecosystems in dry and tropical humid zones. All of the population collapses and growth declines in periods of warm climate occurred in dry and tropical humid zones. Malthusian checks (famines, wars and epidemics) were the dominant triggers of population collapses, which peaked dramatically when climate deteriorated. Main conclusions Global demographic catastrophes and most population collapse incidents occurred in periods with great climate change, owing to overpopulation caused by diminished carrying capacity of the land and the resultant outbreak of Malthusian checks. Impacts of cooling or warming on land carrying capacity varied geographically, as a result of the diversified ecosystems in different parts of the Earth. The observed climate-population synchrony challenges Malthusian theory and demonstrates that it is not population growth alone but climate-induced subsistence shortage and population growth working synergistically, that cause large-scale human population collapses on the long-term scale. © 2010 Blackwell Publishing Ltd.


Wu C.,University of Washington | Hansen S.J.,Fred Hutchinson Cancer Research Center | Hou Q.,South China Normal University | Yu J.,Clemson University | And 6 more authors.
Angewandte Chemie - International Edition | Year: 2011

Lighting up brain tumors: Highly fluorescent nanodots that consist of semiconducting polymer blends were attached to the peptide ligand chlorotoxin. The nanodot-chlorotoxin conjugates were specifically targeted to malignant brain tumors in a transgenic mouse model, thus proving their potential as in vivo probes for clinical cancer diagnostics (see picture). Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wei G.,South China Normal University | Zeng L.,Jiangxi Normal University
Advanced Nonlinear Studies | Year: 2016

In this paper, we study the eigenvalues of the poly-Laplacian with arbitrary order on a bounded domain in an n-dimensional Euclidean space and we obtain a lower bound which generalizes the results due to Cheng and Wei [5] and gives an improvement of the results due to Cheng, Qi and Wei [3]. © 2016 by De Gruyter.


Liu L.-Y.,CAS Guangzhou Institute of Geochemistry | Liu L.-Y.,University of Chinese Academy of Sciences | Wang J.-Z.,CAS Guangzhou Institute of Geochemistry | Wei G.-L.,CAS Guangzhou Institute of Geochemistry | And 3 more authors.
Environmental Pollution | Year: 2012

Sediments collected from the continental shelf of China, embracing Yellow Sea, inner shelf of the East China Sea (ECS), and the South China Sea (SCS), were analyzed for polycyclic aromatic hydrocarbons (PAHs). The concentrations of anthropogenic PAHs (Σ 18PAH) were 27-224 ng/g dry weight, with an average of 82 ng/g. Sedimentary PAHs in the continental shelf off China were mainly derived from mixed residues of biomass, coal, and petroleum combustion. Fluvial transport and atmospheric deposition mainly accounted for sediment PAHs in the ECS inner shelf and Yellow Sea (and the SCS), respectively. Furthermore, statistically higher levels of Σ 18PAH (28-224 ng/g; mean 110 ng/g) in the Yellow Sea sediment than in the SCS sediment (28-109 ng/g; mean 58 ng/g) were probably resulted from higher PAH emissions from coke industry and domestic coal combustion in North China than in South China. © 2012 Elsevier Ltd. All rights reserved.


Seger C.A.,South China Normal University | Seger C.A.,Colorado State University | Braunlich K.,South China Normal University | Wehe H.S.,South China Normal University | Liu Z.,Colorado State University
Journal of Neuroscience | Year: 2015

Effective generalization in a multiple-category situation involves both assessing potential membership in individual categories and resolving conflict between categories while implementing a decision bound. We separated generalization from decision bound implementation using an information integration task in which category exemplars varied over two incommensurable feature dimensions. Human subjects first learned to categorize stimuli within limited training regions, and then, during fMRI scanning, they also categorized transfer stimuli from new regions of perceptual space. Transfer stimuli differed both in distance from the training region prototype and distance from the decision bound, allowing us to independently assess neural systems sensitive to each. Across all stimulus regions, categorization was associated with activity in the extrastriate visual cortex, basal ganglia, and the bilateral intraparietal sulcus. Categorizing stimuli near the decision bound was associated with recruitment of the frontoinsular cortex and medial frontal cortex, regions often associated with conflict and which commonly coactivate within the salience network. Generalization was measured in terms of greater distance from the decision bound and greater distance from the category prototype (average training region stimulus). Distance from the decision bound was associated with activity in the superior parietal lobe, lingual gyri, and anterior hippocampus, whereas distance from the prototype was associated with left intraparietal sulcus activity. The results are interpreted as supporting the existence of different uncertainty resolution mechanisms for uncertainty about category membership (representational uncertainty) and uncertainty about decision bound (decisional uncertainty). © 2015 the authors.


Wang Q.,South China Normal University | Tan C.,South China Normal University | Tamiaki H.,Ritsumeikan University | Chen H.,South China Normal University
Photochemical and Photobiological Sciences | Year: 2010

A novel ternary 2-(2-carboxylphenyl)imidazo[4,5-f]-1,10-phenanthroline- based europium(iii) 2-thenoyltrifluoroacetonate complex with red luminescence was designed and prepared for anion recognition. Spectroscopic studies, including UV-vis, fluorescence and NMR, showed that the sensor exhibited striking emission changes in response to fluoride (green), hydrogen sulfate (blue) and acetate anions (pale blue) due to hydrogen bonding and competitive coordination with the Eu(iii) ions. © 2010 The Royal Society of Chemistry and Owner Societies.


Wang Q.,South China Normal University | Tan C.,South China Normal University | Chen H.,South China Normal University | Tamiaki H.,Ritsumeikan University
Journal of Physical Chemistry C | Year: 2010

The preparation of a novel covalently bonded luminescent hybrid material and its spectrophotometric anion sensing property were reported. The fluorescent receptor (lanthanide complex) was embedded in mesoporous silica through a sol-gel approach, and the nanoscale rod material exhibited excellent photophysical properties (luminescence and thermal stability). It shows significant changes in its fluorescence upon hydrogen binding to fluoride ions in DMSO/H2O (1/1), and the luminescence varies from green to blue (3-4 s). Proton NMR titration studies also indicated that the organic ligand was participating in hydrogen-bonding interactions with fluoride guest anions. The detection limit for fluoride anions could reach 1 μM, and the reusability cycles were performed more than 10 times. © 2010 American Chemical Society.


Hu L.-Y.,Jiangxi Normal University | Hu L.-Y.,South China Normal University | Zhang Z.-M.,South China Normal University
Journal of the Optical Society of America B: Optical Physics | Year: 2012

Theoretical analysis is given of nonclassicality and decoherence of the field states generated by adding any number of photons to the squeezed thermal state (STS). Based on the fact that the squeezed number state can be considered as a single-variable Hermite polynomial excited state, the compact expression of the normalization factor is derived, a Legendre polynomial. The nonclassicality is investigated by exploring the sub-Poissonian and negative Wigner function (WF). The results show that the WF of single-photon-Added STS (PASTS) always has negative values at the phase space center. The decoherence effect on PASTS is examined by the analytical expression of WF. It is found that a longer threshold value of decay time than in single-photon-subtraction STS is included in single PASTS. © 2012 Optical Society of America.


Xu M.,South China Normal University | Xu M.,University of Rhode Island | Zhou L.,University of Rhode Island | Hao L.,South China Normal University | And 3 more authors.
Journal of Power Sources | Year: 2011

Lithium difluoro (oxalate) borate (LiDFOB) is used as thermal stabilizing and solid electrolyte interface (SEI) formation additive for lithium-ion battery. The enhancements of electrolyte thermal stability and the SEIs on graphite anode and LiFePO4 cathode with LiDFOB addition are investigated via a combination of electrochemical methods, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared-attenuated total reflectance (FTIR-ATR), as well as density functional theory (DFT). It is found that cells with electrolyte containing 5% LiDFOB have better capacity retention than cells without LiDFOB. This improved performance is ascribed to the assistance of LiDFOB in forming better SEIs on anode and cathode and also the enhancement of the thermal stability of the electrolyte. LiDFOB-decomposition products are identified experimentally on the surface of the anode and cathode and supported by theoretical calculations. © 2010 Elsevier B.V. All rights reserved.


Hu L.-Y.,South China Normal University | Hu L.-Y.,Jiangxi Normal University | Jia F.,Jiangxi Normal University | Zhang Z.-M.,South China Normal University
Journal of the Optical Society of America B: Optical Physics | Year: 2012

We introduce a kind of entangled state-a photon-addition two-mode squeezed thermal state (TMSTS)-by adding photons to each mode of the TMSTS. Using the P-representation of thermal state, the compact expression of the normalization factor is derived, a Jacobi polynomial. The nonclassicality is investigated by exploring especially the negativity of Wigner function. The entanglement is discussed by using Shchukin-Vogel criteria. It is shown that the photon addition to the TMSTS may be more effective for the entanglement enhancement than the photon subtraction from the TMSTS. In addition, the quantum teleportation is also examined, which shows that symmetrical photon-added TMSTS may be more useful for quantum teleportation than the nonsymmetric case. © 2012 Optical Society of America.


Lai W.-L.,South China Normal University | Lai W.-L.,Jiangxi Normal University | Zhang Y.,South China Normal University | Chen Z.-H.,South China Normal University
Ecological Engineering | Year: 2012

The aim of the present study was to test the correlation between radial oxygen loss (ROL), photosynthesis, and nutrient removal based on the hypothesis that ROL was principally a positive physiological process of wetland plants, and was correlated with photosynthesis and nutrient removal. Thirty five emergent wetland plants were used for the measurement of ROL, photosynthesis, and nutrient removal in micro-scale wetlands in a climate chamber. Significant differences among thirty five species were tested in ROL, photosynthetic rate, and nutrient removal rates. ROL was positively correlated with photosynthetic rate (P= 0.000), transpiration rate (P= 0.005), root activity (P= 0.000), root biomass of D≤ 1 mm (P= 0.002), above-ground biomass (P= 0.030), leaf biomass (P= 0.023), root porosity (P= 0.000), maximum root length (P= 0.011), and removal rates of TN and TP (P= 0.000, 0.002), while negatively related to root biomass of D≥ 3 mm, and root longevity (P= 0.022, 0.007). All the indices which were positively correlated with ROL, also positively correlated with plant growth. The results suggest that ROL may be an active physiological process or at least involves physiological processes of wetland plants. Significant differences existed among different wetland plants in ROL, photosynthesis, and nutrient removal, which should be considered in plant selection for constructed wetlands. © 2011 Elsevier B.V.


Lin J.,South China Normal University | Wang Q.,South China Normal University | Wang Q.,Guangdong Technology Research Center for Ecological Management and Remediation of Urban Water System | Zheng Y.,South China Normal University | Zhang Y.,South China Normal University
CrystEngComm | Year: 2013

The chemical effects of high intensity ultrasound and microwave irradiation on the preparation of europium(iii) activated silver molybdates were investigated and characteristic red emission was successfully achieved at a very low temperature (70°C) in 40 minutes. X-ray powder diffraction results proved that the crystal phase of silver molybdate was heavily related to the pH value. Scanning electron microscopic images revealed rod-like structures of Ag2Mo3O10·1.8H2O and Ag 2Mo2O7 were obtained in the range of pH values between 2 and 5, while growing particles of Ag2MoO4 were formed at pH values of 7 and 8. Furthermore, it has been found that the encapsulation of europium(iii) in monoclinic crystal structure (Ag 2Mo2O7) resulted in enhanced luminescence intensities compared to other crystal phases. © 2013 The Royal Society of Chemistry.


Liu H.,Jiangxi Normal University | Sun D.,South China Normal University
Acta Mathematica Scientia | Year: 2013

In this paper, we define the shared value of an algebroid function and its derivative on its Riemann surface. By considering the relationship between the shared values and the branch points of algebroid functions and their derivatives, we obtain some uniqueness theorems of algebroid functions sharing values with their derivatives, which extend 3 IM shared values theorem of nonconstant meromorphic functions and their derivatives obtained by Mues-Steinmetz and Gundersen. © 2013 Wuhan Institute of Physics and Mathematics.


Hu Y.,South China Normal University | Hu Y.,Colorado State University | Guan J.,South China Normal University | Bernstein E.R.,Colorado State University
Mass Spectrometry Reviews | Year: 2013

Mass-selected IR plus UV/VUV spectroscopy and mass spectrometry have been coupled into a powerful technique to investigate chemical, physical, structural, and electronic properties of radicals, molecules, and clusters. Advantages of the use of vacuum ultraviolet (VUV) radiation to create ions for mass spectrometry are its application to nearly all compounds with ionization potentials below the energy of a single VUV photon, its circumventing the requirement of UV chromophore group, its inability to ionize background gases, and its greatly reduced fragmenting capabilities. In this review, mass-selected IR plus VUV (118 nm) spectroscopy is introduced first in a general manner. Selected application examples of this spectroscopy are presented, which include the detections and structural analysis of radicals, molecules, and molecular clusters in a supersonic jet. © 2013 Wiley Periodicals, Inc. Mass Spec Rev 32:484-501, 2013 © 2013 Wiley Periodicals, Inc.


Hou L.,South China Normal University | Xie Y.,South China Normal University | Ying G.,CAS Guangzhou Institute of Geochemistry | Fang Z.,South China Normal University
Aquatic Toxicology | Year: 2011

The study reported in this paper tested the hypothesis that the developmental and reproductive health of mosquitofish (Gambusia affinis) exposed to pulp and paper effluent in the Dengcun River would differ from that of mosquitofish living in a reference site. We also studied whether morphological characteristics such as the anal fin and hemal spines of mosquitofish could serve as indicators for evaluating the androgenic effect and mosquitofish population security in the Dengcun River. Male and female mosquitofish were captured at three sites contaminated by pulp and paper effluent in the Dengcun River in Sihui, South China, and at a nearby uncontaminated reference site. Samples were collected from the sampling sites on the same day in August 2009. We compared the populations by total length, wet body and liver mass, gonad mass, and population composition. We also compared the populations according to number of anal fin segments, oocyte and embryo count, anal fin and hemal spine morphology among females, and by sperm count and viability among males, and observed the gonadal and liver histology of both males and females. Female mosquitofish exposed to pulp and paper effluent in the Dengcun River were generally smaller in length and mass, had a greater number of anal fin segments and more embryos, but had significantly fewer oocytes in comparison with those living at the reference site. The higher number of anal fin ray 3 segments and the increased ray 4:6 length ratio observed among fish taken from the Dengcun River sites indicated that they might be subject to the androgenic effect. Furthermore, the significantly different hemal spine morphology of the effluent-affected females also indicated the pulp and paper mills effluents in Dengcun River might contain androgenic substance(s). Male mosquitofish at the sites exposed to effluent had a higher number of anal fin segments and greater testis mass in comparison with those living at the reference site. No evidence of intersex was found in either males or females, although histopathological tests on females revealed histologic abnormalities in the liver and gonads. It can be concluded that pulp and paper effluent contamination in the Dengcun River has affected a number of developmental parameters and reproductive characteristics in mosquitofish, with possible adverse effects on reproduction in this population. © 2011 Elsevier B.V.


Liu T.-L.,Wuhan University | He Z.-L.,Wuhan University | Tao H.-Y.,Wuhan University | Cai Y.-P.,CAS Shanghai Institute of Organic Chemistry | And 3 more authors.
Chemical Communications | Year: 2011

A direct and facile synthesis of highly functional 5-aza-spiro[2,4] heptanes, a valuable structural motif for drug discovery, is developed via catalytic asymmetric 1,3-dipolar cycloaddition of cyclopropylidene acetate and azomethine ylides for the first time. © 2011 The Royal Society of Chemistry.


Liao Y.,South China Normal University | Liao Y.,The Texas Institute | Park K.-S.,The Texas Institute | Xiao P.,University of Texas at Austin | And 4 more authors.
Chemistry of Materials | Year: 2013

A layered sulfide, Na0.5NbS2 (space group: P6 3/mmc), was synthesized by a conventional solid-state reaction as an electrode material for a Na-ion battery. Galvanostatic Na insertion/extraction was performed to characterize the system NaxNbS2 (0 ≤ x ≤ 1.0) operating on the Nb(IV)/Nb(III) redox couple. Although the system shows a high specific capacity of 143.6 mAh g-1, the voltage profile is not suitable with a signature of Na/vacancy ordering at x = 0.5. First-principles calculation was applied to reveal possible structures of NaxNbS2 and describe the corresponding electrochemical properties. The calculated Na binding energies and voltages are in good agreement with experimental charge/discharge voltages. We also found a possible atomic arrangement of Na/vacancy ordering in Na0.5NbS2. Although layered NaMS2 systems allow full sodium intercalation, the strong Na+-Na+ intralayer interaction induces layer gliding and Na+-ion ordering that create undesirable steps in the voltage profile. © 2013 American Chemical Society.


Zhang D.,South China Normal University | Zhang D.,University of Hong Kong | Wang Z.,University of Hong Kong | Zhu S.,South China Normal University
Frontiers of Physics | Year: 2012

Quantum simulation is a powerful tool to study a variety of problems in physics, ranging from high-energy physics to condensed-matter physics. In this article, we review the recent theoretical and experimental progress in quantum simulation of Dirac equation with tunable parameters by using ultracold neutral atoms trapped in optical lattices or subject to light-induced synthetic gauge fields. The effective theories for the quasiparticles become relativistic under certain conditions in these systems, making them ideal platforms for studying the exotic relativistic effects. We focus on the realization of one, two, and three dimensional Dirac equations as well as the detection of some relativistic effects, including particularly the well-known Zitterbewegung effect and Klein tunneling. The realization of quantum anomalous Hall effects is also briefly discussed. © 2012 Higher Education Press and Springer-Verlag Berlin Heidelberg.


Zhang D.-W.,South China Normal University | Zhang D.-W.,University of Hong Kong | Xue Z.-Y.,South China Normal University | Yan H.,South China Normal University | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We propose an experimental scheme to detect macroscopic Klein tunneling with spin-orbit-coupled Bose-Einstein condensates (BECs). We show that a nonlinear Dirac equation with tunable parameters can be realized with such BECs. Through numerical calculations, we demonstrate that macroscopic Klein tunneling can be clearly detected under realistic conditions. Macroscopic quantum coherence in such relativistic tunneling is clarified and a BEC with a negative energy is shown to be able to transmit transparently through a wide Gaussian potential barrier. © 2012 American Physical Society.


Huang T.,University of Kentucky | Wang C.,University of Kentucky | Wen H.,South China Normal University
Archive for Rational Mechanics and Analysis | Year: 2012

In this paper, we consider the short time strong solution to a simplified hydrodynamic flow modeling compressible, nematic liquid crystal materials in dimension three. We establish a criterion for possible breakdown of such solutions at a finite time in terms of the temporal integral of both the maximum norm of the deformation tensor of the velocity gradient and the square of the maximum norm of the gradient of a liquid crystal director field. © 2011 Springer-Verlag.


Luo Q.,South China Normal University | Luo Q.,Beijing Institute of Technology
Physical Chemistry Chemical Physics | Year: 2012

The neutral carbon aluminium cluster Al 3C and its anion Al 3C - have been investigated at the B3LYP/6-311+G(d) and BP86/6-311+G(d) levels of theory. It is suggested that the C 2v neutral cluster Al 3C could be considered as a pseudohalogen superatom with a smaller electron affinity than the iodine atom. The DFT calculation results confirm that, similar to the halogen atoms, the pseudohalogen superatom Al 3C cluster could form the compounds corresponding to the dimer, salts, interhalogen compounds, oxides, acid radicals, and coordination complexes as well as superatom compounds of halogen, showing that Al 3C has similar chemical properties to halogens and maintains its integrity in the related reactions. Based on the maintenance of integrity in the chemical assemblies [(Al 3C)(KCAl 3) n] - (n = 1-5), it could be anticipated that the neutral cluster Al 3C holds great potential as a building block for the development of future nanostructured materials. Further, corresponding experimental verifications are invited. This journal is © 2012 the Owner Societies.


Li X.-F.,South China Normal University | Zhang C.-Y.,Guangzhou University | Li H.,South China Normal University | Dai Q.-F.,South China Normal University | And 2 more authors.
Optics Express | Year: 2014

Periodic surface structures with periods as small as about onetenth of the irradiating femtosecond (fs) laser light wavelength were created on the surface of a titanium (Ti) foil by exploiting laser-induced oxidation and third harmonic generation (THG). They were achieved by using 100-fs laser pulses with a repetition rate of 1 kHz and a wavelength ranging from 1.4 to 2.2 μm. It was revealed that an extremely thin TixOy layer was formed on the surface of the Ti foil after irradiating fs laser light with a fluence smaller than the ablation threshold of Ti, leading to a significant enhancement in THG which may exceed the ablation threshold of TixOy. As compared with Ti, the maximum efficacy factor for TixOy appears at a larger normalized wavevector in the direction perpendicular to the polarization of the fs laser light. As a result, the THG-dominated laser ablation of TixO y induces 100-nm periodic structures parallel to the polarization of the fs laser light. The depth of the periodic structures was found to be ∼10 nm by atomic force microscopy and the formation of the thin TixOy layer was verified by energy dispersive X-ray spectroscopy. ©2014 Optical Society of America


Sun H.,Guangzhou University | Lai J.-P.,South China Normal University | Fung Y.S.,University of Hong Kong
Journal of Chromatography A | Year: 2014

A novel method coupling molecular imprinting solid-phase extraction (MISPE) and micellar electrokinetic capillary chromatography (MEKC) was developed to enable the hourly determination of low level of ambient carbonyls, and study their partition between gaseous phase and particulate phase. With 2,4-dinitroaniline (DNAN) as dummy imprinting template, the unreacted 2,4-Dinitrophenylhydrazine (DNPH) in sampling solution could be removed effectively using MISPE, and an average recovery of 97. ±. 5.3% (n= 5) for the carbonyl-DNPH derivatives was achieved. Owing to the high enrichment due to sample clean-up, and the improvement of MEKC separation efficiency, many low abundant carbonyls could be detected by hourly in the field study. © 2014 Elsevier B.V.


Wang Y.,Beijing Institute of Technology | Yin J.,South China Normal University | Ke Y.,Renmin University of China
Nonlinear Analysis: Real World Applications | Year: 2013

This paper is concerned with a spatially heterogeneous Lotka-Volterra competition model with nonlinear diffusion and nonlocal terms, under the Dirichlet boundary condition. Based on the theory of Leray-Schauder's degree, we give sufficient conditions to assure the existence of coexistence periodic solutions, which extends some results of G. Fragnelli et al. © 2012 Elsevier Ltd. All rights reserved.


Wang Y.,Beijing Institute of Technology | Yin J.,South China Normal University
Mathematical Methods in the Applied Sciences | Year: 2013

In this paper, instead of energy methods, we apply the supersolution and subsolution methods to investigate the critical extinction exponents for a polytropic filtration equation with absorption and source, and improve the results of Mu et al. (J. Math. Anal. Appl. 2012; 391:429-440). Copyright © 2012 John Wiley & Sons, Ltd.


Li S.,CAS Lanzhou Institute of Chemical Physics | Li S.,University of Chinese Academy of Sciences | Jia C.,CAS Lanzhou Institute of Chemical Physics | Jia C.,University of Chinese Academy of Sciences | And 7 more authors.
Angewandte Chemie - International Edition | Year: 2011

A word in urea: A strategy of mimicking the scaffold and metal coordination behavior of oligo-2,2′-bipyridine ligands was used to obtain a triple anion helicate from a bis(biurea) receptor and phosphate ions. The successful assembly of the triple helical structure provides guidelines for the design of new anion ligands by taking advantage of the similarities of metal and anion coordination. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Jia C.,CAS Lanzhou Institute of Chemical Physics | Jia C.,South China Normal University | Jia C.,University of Chinese Academy of Sciences | Wu B.,Northwest University, China | And 8 more authors.
Angewandte Chemie - International Edition | Year: 2011

Fatal extraction: The Hofmeister bias for sulfate ions in aqueous environments can be overcome by using a tripodal hexaurea receptor (L) that completely encapsulates the sulfate ion in a complementary cavity protected by hydrophobic aromatic rings (see picture; C-gray, N-blue, O-red, S-yellow). Almost quantitative extraction of sulfate ions from an aqueous to an organic phase is achieved when this receptor is used as a liquid-liquid extractant. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wu N.-Y.,Shangqiu Normal University | Gao W.,Chenguang Biotech | He X.-L.,South China Normal University | Chang Z.,Shangqiu Normal University | Xu M.-T.,Shangqiu Normal University
Biosensors and Bioelectronics | Year: 2013

A direct electrochemical DNA biosensor based on zero current potentiometry was fabricated by immobilization of ssDNA onto gold nanoparticles (AuNPs) coated pencil graphite electrode (PGE). One ssDNA/AuNPs/PGE was connected in series between clips of working and counter electrodes of a potentiostat, and then immersed into the solution together with a reference electrode, establishing a novel DNA biosensor for specific DNA detection. The variation of zero current potential difference (ΔEzcp) before and after hybridization of the self-assembled probe DNA with the target DNA was used as a signal to characterize and quantify the target DNA sequence. The whole DNA biosensor fabrication process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy with the use of ferricyanide as an electrochemical redox indicator. Under the optimized conditions, ΔEzcp was linear with the concentrations of the complementary target DNA in the range from 10nM to 1μM, with a detection limit of 6.9nM. The DNA biosensor showed a good reproducibility and selectivity. Prepared DNA biosensor is facile and sensitive, and it eliminates the need of using exogenous reagents to monitor the oligonucleotides hybridization. © 2012 Elsevier B.V..


Lai J.-P.,South China Normal University | Xie L.,South China Normal University | Sun H.,Guangzhou University | Chen F.,South China Normal University
Analytical and Bioanalytical Chemistry | Year: 2013

The molecularly imprinted polymeric microspheres (MIPMs, 3-5 μm), used as high-performance liquid chromatography (HPLC) and solid-phase extraction (SPE) packing materials for anti-AIDS drug emtricitabine (FTC), were synthesized by precipitation polymerization. The effects of ratio of chloroform to acetonitrile on the morphology and diameter of MIPMs were investigated. The prepared MIPMs were characterized by HPLC. The imprinting factor (2.26) suggests that the resultant MIPMs exhibit good recognition and affinity to FTC. In addition, theMIPMs were used in SPE as packing material for separation and enrichment of FTC. The recovery of FTC on MIPMs cartridge was 97.6 % in standard solution. Finally, the MIPMs cartridge was applied to extract the FTC in human serum samples. Impurities in sample have been mostly removed, and the average recovery of 92.5 % was obtained with a detection limit of 0.005 μg/mL and a linear range of 0.02-4.0 μg/mL. The method established can be used to monitor the FTC in human serum sample with good accuracy and selectivity. © Springer-Verlag Berlin Heidelberg 2012.


Xue Z.-Y.,South China Normal University | Zhou J.,South China Normal University | Zhou J.,Nanjing University | Wang Z.D.,University of Hong Kong
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

To implement a set of universal quantum logic gates based on non-Abelian geometric phases, it is conventional wisdom that quantum systems beyond two levels are required, which is extremely difficult to fulfill for superconducting qubits and appears to be a main reason why only single-qubit gates were implemented in a recent experiment [A. A. Abdumalikov, Jr., Nature (London) 496, 482 (2013)NATUAS0028-083610.1038/nature12010]. Here we propose to realize nonadiabatic holonomic quantum computation in decoherence-free subspace on circuit QED, where one can use only the two levels in transmon qubits, a usual interaction, and a minimal resource for the decoherence-free subspace encoding. In particular, our scheme not only overcomes the difficulties encountered in previous studies but also can still achieve considerably large effective coupling strength, such that high-fidelity quantum gates can be achieved. Therefore, the present scheme makes realizing robust holonomic quantum computation with superconducting circuits very promising. © 2015 American Physical Society.


Zhuang Z.,South China Normal University | Li N.,South China Normal University | Guo Z.,South China Normal University | Zhu M.,South China Normal University | And 2 more authors.
Journal of Biomedical Optics | Year: 2013

Confocal micro-Raman spectroscopy-a valuable analytical tool in biological and medical field of research-allows probing molecular vibrations of samples without external labels or extensive preparation. We employ confocal micro-Raman spectroscopy to characterize renal tumors and normal tissue. Results show that Raman peaks of the renal tumor at 788 and 1087 cm-1, which belong to .sPO2-and .asPO2-stretching, respectively, have an obvious increase. At the same time, the ratio of I855/I831 in renal tumor tissue is 1.39 ± 0.08, while that in normal renal tissue is 2.44 ± 0.05 (p < 0.01). This means that more tyrosine conformation transform from buried to exposed in the presence of cancer. Principal component analysis is used to classify the Raman spectra of renal tumor tissue and normal tissue. © 2013 Society of Photo-Optical Instrumentation Engineers.


Wang Y.,Beijing Institute of Technology | Yin J.,South China Normal University
Nonlinear Analysis: Real World Applications | Year: 2011

In this paper, we investigate a class of degenerate parabolic periodic equations with nonlocal terms under Neumann boundary conditions. By using the theory of the Leray-Schauder degree, we obtain the existence of non-trivial nonnegative periodic solutions. © 2011 Elsevier Ltd. All rights reserved.


Zhu S.-L.,South China Normal University | Shao L.-B.,University of Hong Kong | Wang Z.D.,University of Hong Kong | Duan L.-M.,University of Michigan
Physical Review Letters | Year: 2011

We propose an experiment to directly probe the non-Abelian statistics of Majorana fermions by braiding them in an s-wave superfluid of ultracold atoms. We show that different orders of braiding operations give orthogonal output states that can be distinguished through Raman spectroscopy. Realization of Majorana states in an s-wave superfluid requires strong spin-orbital coupling and a controllable Zeeman field in the perpendicular direction. We present a simple laser configuration to generate the artificial spin-orbital coupling and the required Zeeman field in the dark-state subspace. © 2011 American Physical Society.


Liu Q.,South China Normal University | Zhu X.,Shangqiu Normal University | Huo Z.,South China Normal University | He X.,South China Normal University | And 2 more authors.
Talanta | Year: 2012

Graphene (GR) was synthesized through electrochemical reduction of graphene oxide and characterized by spectroscopic and electrochemical techniques. Polyvinylpyrrolidone (PVP)/graphene modified glassy carbon electrode (PVP/GR/GCE) was prepared and applied for the fabrication of dopamine (DA) sensors without the interference of ascorbic acid (AA). Compared to bare GCE, an increase of current signal was observed, demonstrating that PVP/GR/GCE exhibited favorable electron transfer kinetics and electrocatalytic activity towards the oxidation of dopamine. Furthermore, PVP/GR/GCE exhibited good ability to suppress the background current from large excess ascorbic acid. Amperometric response results show that the PVP based sensor displayed a wide linear range of 5×10-10 to 1.13×10-3 mol/L DA with a correlation coefficient of 0.9990 and a detection limit of 0.2 nM (S/N=3). The determination of dopamine in urine and human serum samples were studied. © 2012 Elsevier B.V. All rights reserved.


Zhao R.-R.,South China Normal University | Hung I.-M.,Yuan Ze University | Li Y.-T.,Yuan Ze University | Chen H.-Y.,South China Normal University | And 2 more authors.
Journal of Alloys and Compounds | Year: 2012

A series of olivine LiFe 1-xCo xPO 4 composites were synthesised by a hydrothermal route under reductive atmosphere. The structure of the prepared samples was characterised by X-ray diffraction. Morphology, particle size, and elemental concentration were observed by scanning electron microscopy, high-resolution transmission electron microscopy, and corresponding EDS mapping, respectively. Raman spectroscopy was employed to study the surface information of the carbon-coated LiFe 1-xCo xPO 4. The electrochemical properties of the samples were studied by AC impedance spectroscopy and charge-discharge instruments at room temperature. The discharge capacity of LiFe 3/4Co 1/4PO 4/C is 170 mAh/g at rate of 0.1 C. LiFe 1-xCo xPO 4 can achieve a higher discharge plateau (∼3.5 V) than does pure LiFePO 4 (∼3.4 V). The results indicate that the Co-doped sample exhibits improved electrochemical performance at low discharge rates. However, XPS results show that the Li-O band stabilises further as the doping amount increase, which is not beneficial to the lithium diffusion coefficient of the compound. © 2011 Elsevier B.V. All rights reserved.


Liu Z.,South China Normal University | Xu X.,South China Normal University | Fang J.,South China Normal University | Zhu X.,South China Normal University | And 2 more authors.
Applied Surface Science | Year: 2012

Reverse microemulsions, consisting of n-hexanol, Triton X-100, Cyclohexane and aqueous salt solutions, were used to synthesize BiOI, TiO 2 and BiOI/TiO 2 hybrid nanoparticles at room temperature. The particles had been characterized by X-ray powder diffraction, FT-IR spectra, TG-DSC analysis, nitrogen sorption, electron microscopy, and UV-vis diffuse reflectance spectroscopy. The photocatalytic properties of those particles were evaluated by degradation of methyl orange under visible light irradiation. The BiOI/TiO 2 composites showed about 5 times higher photocatalytic performances than BiOI when the mole ratio of BiOI to TiO 2 was 75%. The remarkable enhancement in the visible light photocatalytic activities of the BiOI/TiO 2 heterostructures could be first attributed to the effective electron-hole separations at the interfaces of the two semiconductors, which facilitated the transfer of the photoinduced carriers. Meanwhile, the heterojunction formed between BiOI and TiO 2 would further retard the recombination of photoinduced carriers. In addition, high degree of crystallization, bimodal porous structure, relative large specific surface area, and appropriate energy band gap have great contribution to the enhancement of photocatalytic performance. © 2011 Elsevier B.V. All rights reserved.


Wang X.,South China Normal University | Wang X.,University of Hong Kong | Li X.-Y.,University of Hong Kong
Materials Science and Engineering B: Solid-State Materials for Advanced Technology | Year: 2014

A layered CdS/ZnS catalyst film was synthesized on glass using the stepped chemical bath deposition method. The film catalyst was shown as visible light-driven photocatalyst capable of producing H2 under visible light. The ZnS outer layer helped suppress the recombination of photo-generated electron-hole pairs on the CdS base layer, leading to faster H2 generation. The use of the ZnS layer also greatly improved the stability of the catalyst film and prevented the leaching of Cd2+ from the CdS layer. Deposition of Ru on the catalyst film further increased its photoreactivity for H2 production. The photocatalyst was effective in H2 production together with the degradation of model organic substances, such as formic acid, methanol, and ethanol. The greatest H2 production rates were achieved using the CdS/ZnS/Ru film in the formic acid solution at 123 μmol/m2-h under visible light and 135 mmol/m2-h under the simulated solar light. The corresponding theoretical reduction rates of chemical oxygen demand (COD) were 1.9 and 2.1 g/m2-h, respectively. As the multilayer CdS/ZnS/Ru film catalyst can be easily separated from water, it has a great potential for simultaneous photocatalytic hydrogen generation and organic wastewater treatment using solar energy. © 2013 Elsevier B.V.


Deng D.,South China Normal University | Chen C.,South China Normal University | Zhao X.,Taishan Medical University | Li H.,Guangzhou University
Applied Physics B: Lasers and Optics | Year: 2013

The propagation dynamics of an Airy beam superimposed with a unit topological charge optical vortex is investigated analytically and numerically in uniaxial crystals orthogonal to the optical axis. Upon propagation, the Airy vortex beam is mainly dependent on the ratio of the extraordinary refractive index to the ordinary refractive index. Due to the anisotropic effect of the crystals, the acceleration of an Airy vortex beam in the transversal direction along the optical axis is more rapidly than that in the other transversal direction, which is alike to a conventional Airy beam but with twice the vortex acceleration velocity. © 2013 Springer-Verlag Berlin Heidelberg.


Zha Z.,Luoyang Normal University | Zha Z.,University of Chinese Academy of Sciences | Wang X.,South China Normal University
IEEE Transactions on Information Theory | Year: 2011

In this paper, two new families of functions in odd characteristic are constructed, and they are proved to be almost perfect nonlinear (APN) functions. Some of the open cases which were introduced by Helleseth are answered by these new APN functions. © 2011 IEEE.


Peng W.-C.,University of Hong Kong | Wang X.,University of Hong Kong | Wang X.,South China Normal University | Li X.-Y.,University of Hong Kong
Nanoscale | Year: 2014

The photo-degradation of organic pollutants using solar light is an attractive chemical process for water pollution control. In this study, we synthesized a new composite material consisting of silver phosphate (Ag 3PO4) sub-microcrystals grown on a layered molybdenum disulfide (MoS2) and graphene (GR) hybrid as a high-performance photocatalyst for the degradation of toxic organic pollutants. This composite photocatalyst was prepared via a simple two-step hydrothermal process that used sodium molybdate, thiourea and graphene oxide as precursors for the MoS 2/GR hybrid and silver nitrate for the Ag3PO4 sub-microcrystals. The composite Ag3PO4-0.02(MoS 2/0.005GR) was found to be the most effective catalyst for the photo-decomposition of 2,4-dichlorophenol under simulated solar light and visible light (λ ≥ 420 nm). The photocatalyst was also highly active for the degradation of nitrophenol and chlorophenol. The ultra photocatalytic activity of the novel catalyst arose from the synergetic effects of MoS 2 and GR as cocatalysts in the composite. MoS2/GR nanosheets served as electron collectors for the interfacial electron transfer from Ag3PO4 to electron acceptors in the aqueous solution and thus enhanced the separation of the photo-generated electron-hole pairs and made the holes more available for organic oxidation. In addition, the presence of MoS2 and GR provided more active adsorption sites and allowed for the activation of dissolved O2 for organic degradation in water. © 2014 the Partner Organisations.


Jie W.,Hong Kong Polytechnic University | Chen X.,University of Hong Kong | Li D.,University of Hong Kong | Li D.,South China Normal University | And 5 more authors.
Angewandte Chemie - International Edition | Year: 2015

Gallium selenide, an important second-order nonlinear semiconductor, has received much scientific interest. However, the nonlinear properties in its two-dimensional (2D) form are still unknown. A strong second harmonic generation (SHG) in bilayer and multilayer GaSe sheets is reported. This is also the first observation of SHG on 2D GaSe thin layers. The SHG of multilayer GaSe above five layers shows a quadratic dependence on the thickness; while that of a sheet thinner than five layers shows a cubic dependence. The discrepancy between the two SHG responses is attributed to the weakened stability of non-centrosymmetric GaSe in the atomically thin flakes where a layer-layer stacking order tends to favor centrosymmetric modification. Importantly, two-photon excited fluorescence has also been observed in the GaSe sheets. Our free-energy calculations based on first-principles methods support the observed nonlinear optical phenomena of the atomically thin layers. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.


Lai J.-P.,South China Normal University | Chen F.,South China Normal University | Sun H.,Guangzhou University | Fan L.,South China Normal University | Liu G.-L.,South China Normal University
Journal of Separation Science | Year: 2014

Molecularly imprinted microspheres (MIMs) for the anticancer drug aminoglutethimide (AG) were synthesized by aqueous suspension polymerization. The expected size and diameter of MIMs are controlled easily by changing one of the surfactant types, ratio of organic-to-water phase or stirring rate during polymerization. The obtained MIMs exhibit specific affinity toward AG with imprinting factor of 3.11 evaluated with a chromatographic model. The resultant MIMs were used as the SPE materials for the extraction of AG from human urine. A molecularly imprinted SPE (MISPE) method coupled with HPLC has been developed for the extraction and detection of AG in urine. Our results showed that most impurities from urine can be removed effectively after a washing step and the AG has been enriched effectively after MISPE operation with the recovery of >90% (n=3). The developed MISPE-HPLC method could be used for enrichment and detection of AG in human urine. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Liu J.,South China Normal University | Liu J.,Fuzhou University | Liu B.,South China Normal University
Match | Year: 2011

Let G be a graph on n vertices. It was found that the ordinary energy E(G) and the Laplacian energy LE(G) have a number of analogous properties. In particular, if G is regular, then E(G) = LE(G) , and there are non-regular graphs with the same property. In this paper we consider the non-regular non-isomorphic connected graphs of the same order with the same energy and Laplacian energy, called as E-L equienergetic graphs. We construct a pair of E-L equienergetic graphs on n vertices for n ≡ 0 (mod 7) . Thus it is shown that there exist infinitely many pairs of E-L equienergetic graphs.


Zhou K.,CAS Institute of Biophysics | Mo L.,South China Normal University | Kay P.,University of California at Berkeley | Kay P.,International Computer Science Institute | And 3 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2010

Linguistic categories have been shown to influence perceptual discrimination, to do so preferentially in the right visual field, to fail to do so when competing demands are made on verbal memory, and to vary with the color-term boundaries of different languages. However, because there are strong commonalities across languages in the placement of color-term boundaries, the question remains open whether observed categorical perception for color can be entirely a result of learned categories or may rely to some degree on innate ones. We show here that lateralized color categorical perception can be entirely the result of learned categories. In a visual search task, reaction times to targets were faster in the right than the left visual field when the target and distractor colors, initially sharing the same linguistic term (e.g., "blue"), became between-category colors after training (i.e., when two different shades of blue had each acquired a new name). A control group, whose conditions exactly matched those of the experimental group except that no new categories were introduced, did not show this effect, establishing that the effect was not dependent on increased familiarity with either the color stimuli or the task. The present results show beyond question that lateralized categorical perception of color can reflect strictly learned color categories, even artificially learned categories that violate both universal tendencies in color naming and the categorization pattern of the language of the subject.


Zhang R.,Guangzhou University | Zhang R.,South China Normal University | Chen Z.,South China Normal University
Acta Mathematica Scientia | Year: 2013

In this paper, meromorphic solutions of Riccati and linear difference equations are investigated. The growth and Borel exceptional values of these solutions are discussed, and the growth, zeros and poles of differences of these solutions are also investigated. Furthermore, several examples are given showing that our results are best possible in certain senses. © 2013 Wuhan Institute of Physics and Mathematics.


Yin C.,South China Normal University | He Y.,Guangdong Polytechnic Normal University | Li H.,Guangzhou University | Xie J.,Foshan University
Optics Express | Year: 2012

We study the solitons in parity-time symmetric potential in the medium with spatially modulated nonlocal nonlinearity. It is found that the coefficient of the spatially modulated nonlinearity and the degree of the uniform nonlocality can profoundly affect the stability of solitons. There exist stable solitons in low-power regionand unstable solitons in high-power region. In the unstable casesthe solitons exhibit jump from the original site to the next oneand they can continue the motion into the other lattices. The region of the stable soliton can be expanded by increasing the coefficient of the modulated nonlocality. Finallycritical amplitude of the imaginary part of the linear PT lattices is obtainedabove which solitons are unstable and decay immediately. © 2012 Optical Society of America.


Deng D.,South China Normal University | Li H.,Guangzhou University
Applied Physics B: Lasers and Optics | Year: 2012

The propagation of the Airy-Gaussian beams is studied in strongly nonlocal nonlinear media analytically and numerically. The linear momentum of the analytical Airy-Gaussian beam solution of the Snyder-Mitchell model is not conservational, which is the reason that results in the disagreement between the analytical Airy-Gaussian beam solution and the numerical simulations of the nonlocal nonlinear Schrödinger equation in the case of strong nonlocality. The quasi-Airy-Gaussian soliton in the Gaussian-shaped response material can be obtained when the parameter χ 0 is large enough, and the patterns of Airy-Gaussian beams are variable periodically in liquid crystal material during propagation. © Springer-Verlag 2011.


Wu Q.,South China Normal University | Wu Q.,CAS Wuhan Institute of Physics and Mathematics | Wu Q.,Guangdong Medical University | Zhang J.-Q.,CAS Wuhan Institute of Physics and Mathematics | And 3 more authors.
Optics Express | Year: 2015

In contrast to the optomechanically induced transparency (OMIT) defined conventionally, the inverse OMIT behaves as coherent absorption of the input lights in the optomechanical systems. We characterize a feasible inverse OMIT in a multi-channel fashion with a double-sided optomechanical cavity system coupled to a nearby charged nanomechanical resonator via Coulomb interaction, where two counter-propagating probe lights can be absorbed via one of the channels or even via three channels simultaneously with the assistance of a strong pump light. Under realistic conditions, we demonstrate the experimental feasibility of our model by considering two slightly different nanomechanical resonators and the possibility of detecting the energy dissipation of the system. In particular, we find that our model turns to be a unilateral inverse OMIT once the two probe lights are different with a relative phase, and in this case the relative phase can be detected precisely. © 2015 Optical Society of America.


Zhou J.,Anhui Xinhua University | Zhou J.,South China Normal University | Yu W.-C.,South China Normal University | Gao Y.-M.,University of Electronic Science and Technology of China | Xue Z.-Y.,South China Normal University
Optics Express | Year: 2015

A cavity QED implementation of the non-adiabatic holonomic quantum computation in decoherence-free subspaces is proposed with nitrogen-vacancy centers coupled commonly to the whispering-gallery mode of a microsphere cavity, where a universal set of quantum gates can be realized on the qubits. In our implementation, with the assistant of the appropriate driving fields, the quantum evolution is insensitive to the cavity field state, which is only virtually excited. The implemented non-adiabatic holonomies, utilizing optical transitions in the Λ type of three-level configuration of the nitrogen-vacancy centers, can be used to construct a universal set of quantum gates on the encoded logical qubits. Therefore, our scheme opens up the possibility of realizing universal holonomic quantum computation with cavity assisted interaction on solid-state spins characterized by long coherence times. © 2015 Optical Society of America.


Luo Z.-C.,South China Normal University | Liu M.,South China Normal University | Liu H.,South China Normal University | Zheng X.-W.,South China Normal University | And 5 more authors.
Optics Letters | Year: 2013

We report on the generation of passive harmonic mode locking of a fiber laser using a microfiber-based topological insulator (TI) Bi2Te3 saturable absorber (SA). The optical deposition method was employed to fabricate the microfiber-based TISA. By virtue of the excellent nonlinear optical property of the proposed TISA, the fiber laser could operate at the pulse repetition rate of 2.04 GHz under a pump power of 126 mW, corresponding to the 418th harmonic of fundamental repetition frequency. The results demonstrate that the microfiber-based TI photonic device can operate as both the high nonlinear optical component and the SA in fiber lasers, and could also find other applications in the related fields of photonics. © 2013 Optical Society of America.


Liu H.,South China Normal University | Zheng X.-W.,South China Normal University | Liu M.,South China Normal University | Zhao N.,South China Normal University | And 6 more authors.
Optics Express | Year: 2014

We reported on the generation of femtosecond pulse in a fiber ring laser by using a polyvinyl alcohol (PVA)-based topological insulator (TI), Bi2Se3 saturable absorber (SA). The PVA-TI composite has a low saturable optical intensity of 12 MW/cm2 and a modulation depth of ∼3.9%. By incorporating the fabricated PVA-TISA into a fiber laser, mode-locking operation could be achieved at a low pump threshold of 25 mW. After an optimization of the cavity parameters, optical pulse with ∼660 fs centered at 1557.5 nm wavelength had been generated. The experimental results demonstrate that the PVA could be an excellent host material for fabricating high-performance TISA, and also indicate that the filmy PVA-TISA is indeed a good candidate for ultrafast saturable absorption device. © 2014 Optical Society of America.


You J.,South China Normal University | Lin M.-P.,National Taiwan Normal University
Journal of Consulting and Clinical Psychology | Year: 2015

Objective: This study predicted suicide attempts (SA) by time-varying frequency of nonsuicidal self-injury (NSSI) beyond the contributions of their shared risk factors and examined gender differences in this association. This study also tested for a moderating effect of NSSI in the relationship between suicide ideation (SI) and SA. Method: A large number of Chinese adolescents participated in this study (the exact number of participants varied from 3,623 to 6,911 in different analyses). They completed questionnaires assessing NSSI, SA, SI, borderline personality disorder features, depressive symptoms, and self-criticism 3 times at 6-month intervals. Generalized estimating equations were used to test the hypotheses. Results: In females, but not in males, NSSI was significantly associated with future SA after controlling for the effects of shared risk factors. With the same frequency of SI, the frequency of NSSI also enhanced the risk for future SA. Conclusions: This study established a longitudinal association between NSSI and SA, which could not be fully accounted for by their shared risk factors, in Chinese female community adolescents. Moreover, female adolescents who frequently engage in NSSI may gain the capability for attempting suicide. © 2014 American Psychological Association.


Zeng J.,CAS Institute of Chemistry | Jing L.,CAS Institute of Chemistry | Hou Y.,CAS Institute of Chemistry | Jiao M.,CAS Institute of Chemistry | And 6 more authors.
Advanced Materials | Year: 2014

The effect of the anchoring group of surface ligands on the magnetic properties, especially relaxometric properties, of PEGylated Fe 3O4 nanoparticles is investigated. Systematic experimental results together with in-depth theoretical analysis reveal that the ligand binding affinity can largely vary the saturation magnetization, whereas conjugated anchoring groups can remarkably enhance the transverse relaxivity, which highlights a novel approach for achieving high-performance MRI contrast agents. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Wang Y.,Jinan University | Smith Jr. W.O.,Virginia Institute of Marine Science | Wang X.,Ocean University of China | Li S.,South China Normal University
Geophysical Research Letters | Year: 2010

Recent investigations into the role of carbon dioxide on phytoplankton growth and composition have clearly shown differential effects among species and assemblages, suggesting that increases in oceanic CO2 may play a critical role in structuring lower trophic levels of marine systems in the future. Furthermore, alarming increases in the occurrence of harmful algal blooms (HABs) in coastal waters have been observed, and while not uniform among systems, appear in some manner to be linked to human impacts (eutrophication) on coastal systems. Models of HABs are in their infancy and do not at present include sophisticated biological effects or their environmental controls. Here we show that subtle biological responses occur in the HAB species Phaeocystis globosa Scherffel as a result of CO2 enrichment induced by gentle bubbling. The alga, which has a polymorphic life history involving the formation of both colonies and solitary cells, exhibited altered growth rates of colonial and solitary forms at [CO2] of 750 ppm, as well as increased colony formation. In addition, substantial modifications of elemental and photosynthetic constituents of the cells (C cell-1, N cell -1, potential quantum yield, chl a cell-1) occurred under elevated CO2 concentrations compared to those found at present CO2 levels. In contrast, other individual and population variables (e.g., colony diameter, total chlorophyll concentration, carbon/nitrogen ratio) were unaffected by increased CO2. Our results suggest that predictions of the future impacts of Phaeocystis blooms on coastal ecosystems and local biogeochemistry need to carefully examine the subtle biological responses of this alga in addition to community and ecosystem effects. Copyright © 2010 by the American Geophysical Union.


Li W.,South China Normal University | Tu X.,Luofeng Elementary School
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Knowledge building is the process to create knowledge as a result of improved ideas and collective responsibility. This study introduced knowledge building theory to the comprehensive practice course in primary school, and examined their adaptability using action research method for three months. It focused how individual viewpoint and collective opinion are produced and pushed forth, and the level of collective cognitive responsibility attained by students in the process of collaborative learning. Based on these, a series of online and offline activities including grouping, discussion, independent inquisition, collaborative task, and so on, are designed to promote the students' knowledge building. According to the characteristics of the class and students, there still needs a long period to organize online and offline activities with various resources step and stop in order to get a satisfied result. © 2012 Springer-Verlag.


Wen P.X.,South China Normal University | Dong L.,Software Testing Center
Proceedings - 4th International Conference on Emerging Intelligent Data and Web Technologies, EIDWT 2013 | Year: 2013

Software-as-a-Service (SaaS) is a new service delivery model which allows customers to use the provider's applications running on a cloud infrastructure, SaaS is commonly utilized and it provides benefits to service providers and customers. As more and more SaaS service emerges, how to select qualified provider is a key problem to customers. Current quality model do not consider key features of SaaS such as security and quality of service (QoS). In this paper, a new quality model is proposed which measure the security, quality of service, and software quality of the SaaS service, from the perspective of platform, provider and customer separately. Base the quality model we proposed an evaluating model which classify the SaaS service into four level, including basic level, standard level, optimized level and integrated level. By using the quality model and evaluating model, customer can evaluate the provider and the provider can use it for quality management. © 2013 IEEE.


Wang W.,Minzu University of China | Long D.,Minzu University of China | Liang Y.,University of Electronic Science and Technology of China | Zhang G.,Minzu University of China | And 2 more authors.
Langmuir | Year: 2011

We describe a novel route for the conversion of hexagonal Sb 2Te3 nanoplates into nanorings driven by growth temperature in a simple solvothermal process. The transmission electron microscopy was employed to investigate systemically the morphology, size, crystallinity, and microstructure of the as-prepared products. The experiments indicated that the growth temperature had a great effect on the morphology of antimony telluride nanostructures. When the experiments were conducted at 200 °C, the hexagonal antimony telluride nanoplates were obtained. However, if the experiments were carried out at higher temperature of 230 °C, the hexagonal antimony telluride nanorings were achieved by dissolution of the inner part with a higher density of defects of the hexagonal nanoplates for the first time. A possible formation mechanism was proposed on the basis of experimental results and analysis. This work may open a new rational route for the synthesis of the hexagonal antimony telluride nanorings, which may have scientific and technological applications in various functional devices. © 2010 American Chemical Society.


You J.,South China Normal University | Lin M.-P.,National Taiwan Normal University | Leung F.,Chinese University of Hong Kong
Journal of Adolescence | Year: 2013

This study examined functions of nonsuicidal self-injury (NSSI) among a large sample of Chinese high school students over a six-month period. Among Chinese adolescents, we identified three factors of NSSI functions, namely, Affect Regulation, Social Influence, and Social Avoidance. Affect Regulation was the most frequently endorsed function of NSSI, followed by Social Influence and Social Avoidance. Adolescent male self-injurers were more likely to endorse the Social Influence function than their female counterparts. Moderate/Severe Self-injurers did not differ from Minor Self-injurers on the endorsement of various NSSI functions. All functions of NSSI exhibited small to moderate stability over the six-month assessment period. Findings suggest that Chinese adolescents engaged in NSSI for multiple reasons. These reasons also varied considerably over time within individuals. Assessment of NSSI should thus regularly assess functions of the behavior. © 2013 The Foundation for Professionals in Services for Adolescents.


You J.,South China Normal University | Lin M.P.,National Taiwan Normal University | Fu K.,Chinese University of Hong Kong | Leung F.,Chinese University of Hong Kong
Journal of Abnormal Child Psychology | Year: 2013

This study examined associations of peer socialization and selection, over time, with nonsuicidal self-injury (NSSI) among 5,787 (54.2 % females) Chinese community adolescents. Both effects were tested using two aspects of adolescents' friendship networks: the best friend and the friendship group. Participants completed questionnaires assessing NSSI, depressive symptoms and maladaptive impulsive behaviors at two waves of time over a 6-month period. Results showed that even after controlling for the effects of depressive symptoms and maladaptive impulsive behaviors, the best friends' engagement in NSSI still significantly predicted adolescents' own engagement in NSSI. Adolescents' friendship groups' NSSI status also significantly predicted their own NSSI status and frequency. Additionally, adolescents with NSSI tended to join peer groups with other members also engaging in NSSI. © 2013 Springer Science+Business Media New York.


Hong W.,South China Normal University | Guo Q.,South China Normal University | Li L.,Shanxi University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

The dynamics of optical pulses in noninstantaneous Kerr media are considered. It is found that the "mass center" of the localized profile exhibits an accelerated transversal (on the time axis) motion during propagation. In the highly noninstantaneous regime, especially, the motion can approximately be uniformly accelerated up to one dispersion length, which is also proportional to the ratio between the pulse power and the relaxation time of the media. The evolutions of the pulse width and chirp are also investigated. An interesting phenomenon is found: the nonlinearity-induced chirp in the highly noninstantaneous regime is the "inverted image" of the pulse shape. Based on the acceleration property of the transversal motion, the existence of soliton-like solutions in the noninstantaneous Kerr system is also discussed. It is found that the highly noninstantaneous Kerr system has no soliton-like solutions. © 2015 American Physical Society.


Yang K.,CAS Guangzhou Institute of Biomedicine and Health | Yang K.,South China Normal University | Li Z.,Methodist Hospital Research Institute | Wang Z.,South China Normal University | And 2 more authors.
Organic Letters | Year: 2011

8-Hydroxyquinolin-N-oxide was found to be a very efficient ligand for the copper-catalyzed hydroxylation of aryl iodides, aryl bromides, or aryl chlorides under mild reaction conditions. This methodology provides a direct transformation of aryl halides to phenols and to alkyl aryl ethers. The inexpensive catalytic system showed great functional group tolerance and excellent selectivity. © 2011 American Chemical Society.


Liu X.,Beijing University of Chemical Technology | Yang Z.,Beijing University of Chemical Technology | Zhang R.,Beijing University of Chemical Technology | Li Q.,South China Normal University | Li Y.,Beijing University of Chemical Technology
Journal of Physical Chemistry C | Year: 2012

The N 2O decomposition mechanism is investigated over Cu-ZSM-5 using density functional theory (DFT). Though the mechanism is extended from Fe/Co-ZSM-5, the results show that a different step may be rate-determining over Cu-ZSM-5 compared to the Fe/Co-ZSM-5 system. In the beginning, Z[Cu] as active center decomposes the first N 2O and generates Z[CuO] (process 1), and the energy barrier of N 2O dissociation is 35.18 kcal/mol. Then Z[CuO] could decompose the second N 2O and generate Z[CuOO] (process 2), and the energy barrier of N 2O dissociation is 28.07 kcal/mol. In process 2, oxygen could desorb from Z[CuOO], and the desorption energy is 39.48 kcal/mol, which is only higher 4.30 kcal/mol than 35.18 kcal/mol in the process 1. However the corresponding rate constants show approximately that the rate-limiting step is O 2 desorption in process 2 and not the N 2O dissociation in process 1. Next, if Z[CuOO] could not desorb O 2, it could decompose the third N 2O and generate Z[CuO(O 2)] (process 3). In this process, the energy barrier for N 2O dissociation and the O 2 desorption energy from Z[CuO(O 2)] are 42.10 and 63.42 kcal/mol, respectively, which are much higher than the former processes. It indicates the presence of O 2 could inhibit the N 2O decomposition over Cu-ZSM-5, which is in line with the kinetic experiment. The results suggest the process 1 and 2 are the main catalytic cycle in N 2O decomposition. Importantly, O 2 desorption from Z[CuOO] shows that the mechanism over Cu-ZSM-5 is different from that over Fe/Co-ZSM-5 system. © 2012 American Chemical Society.


You J.,South China Normal University | Lin M.-P.,National Taiwan Normal University | Leung F.,Chinese University of Hong Kong
Journal of Abnormal Child Psychology | Year: 2014

This study tested a longitudinal moderated mediation model of the engagement in non suicidal self-injury (NSSI) based on Nock’s (2009) integrated theoretical model of the development of NSSI. We assessed general predisposing factors (i.e. borderline personality disorder features), precipitating factors (i.e. negative emotions), and NSSI-specific vulnerability factors (i.e. behavioral impulsivity and self-criticism) among 3,600 Chinese secondary school adolescents (56.6 % females, aged between 12 and 18 years). Assessments were conducted for three times, 6 months apart. Results supported the longitudinal mediation model, such that negative emotions mediated the relation of borderline personality disorder features to NSSI. The moderating effects of behavioral impulsivity and self-criticism were both significant, indicating that adolescents with higher levels of both variables were more likely to engage in NSSI. Moreover, behavioral impulsivity made additional contribution to the prediction of future NSSI above and beyond the effects of other risk factors. Findings of this study may help to elucidate the diverse roles of different types of risk factors in the engagement in NSSI, and may also shed new light on our understanding about the nature of this behavior. © 2014, Springer Science+Business Media New York.


Xia Q.,Southwest University | Li S.,CAS Institute of Plant Physiology and Ecology | Feng Q.,South China Normal University
Annual Review of Entomology | Year: 2014

Significant progress has been achieved in silkworm (Bombyx mori) research since the last review on this insect was published in this journal in 2005. In this article, we review the new and exciting progress and discoveries that have been made in B. mori during the past 10 years, which include the construction of a fine genome sequence and a genetic variation map, the evolution of genomes, the advent of functional genomics, the genetic basis of silk production, metamorphic development, immune response, and the advances in genetic manipulation. These advances, which were accelerated by the genome sequencing project, have promoted B. mori as a model organism not only for lepidopterans but also for general biology. © Copyright ©2014 by Annual Reviews.All rights reserved.


Huang Y.,South China Normal University | Kendrick K.M.,University of Electronic Science and Technology of China | Yu R.,South China Normal University
Psychological Science | Year: 2014

When people are faced with opinions different from their own, they often revise their own opinions to match those held by other people. This is known as the social-conformity effect. Although the immediate impact of social influence on people's decision making is well established, it is unclear whether this reflects a transient capitulation to public opinion or a more enduring change in privately held views. In an experiment using a facial-attractiveness rating task, we asked participants to rate each face; after providing their rating, they were informed of the rating given by a peer group. They then rerated the same faces after 1, 3, or 7 days or 3 months. Results show that individuals' initial judgments are altered by the differing opinions of other people for no more than 3 days. Our findings suggest that because the social-conformity effect lasts several days, it reflects a short-term change in privately held views rather than a transient public compliance. © The Author(s) 2014.


Huang Y.,South China Normal University | Kendrick K.M.,University of Electronic Science and Technology of China | Yu R.,South China Normal University
Neuropsychologia | Year: 2014

When people have different opinions, they often adjust their own attitude to match that of others, known as social conformity. How social conflicts trigger subsequent conformity remains unclear. One possibility is that a conflict with the group opinion is perceived as a violation of social information, analogous to using wrong grammar, and activates conflict monitoring and adjustment mechanisms. Using event related potential (ERP) recording combined with a face attractiveness judgment task, we investigated the neural encoding of social conflicts. We found that social conflicts elicit an N400-like negative deflection, being more negative for conflict with group opinions than no-conflict condition. The social conflict related signals also have a bi-directional profile similar to reward prediction error signals: it was more negative for under-estimation (i.e. one[U+05F3]s own ratings were smaller than group ratings) than over-estimation, and the larger the differences between ratings, the larger the N400 amplitude. The N400 effects were significantly diminished in the non-social condition. We conclude that social conflicts are encoded in a bidirectional fashion in the N400-like component, similar to the pattern of reward-based prediction error signals. Our findings also suggest that the N400, a well-established ERP component encoding semantic violation, might be involved in social conflict processing and social learning. © 2014.


Ma P.-C.,South China Normal University | Ma P.-C.,CAS Wuhan Institute of Physics and Mathematics | Ma P.-C.,Huaiyin Normal University | Zhang J.-Q.,CAS Wuhan Institute of Physics and Mathematics | And 3 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We study the dynamics of a driven optomechanical cavity coupled to a charged nanomechanical resonator via Coulomb interaction, in which the tunable double optomechanically induced transparency (OMIT) can be observed from the output field at the probe frequency by controlling the strength of the Coulomb interaction. We calculate the splitting of the two transparency windows, which varies near linearly with the Coulomb coupling strength in a robust way against the cavity decay. Our double-OMIT is much different from the previously mentioned double-EIT or double-OMIT, and might be applied to measure the Coulomb coupling strength. © 2014 American Physical Society.


Fu P.,Indiana State University | Weng Q.,South China Normal University | Weng Q.,Indiana State University
Remote Sensing of Environment | Year: 2016

Land surface temperature (LST), derived from satellite thermal infrared (TIR) sensors, is a key variable for characterization of urban heat island, modeling of surface energy balance, estimation of evapotranspiration and soil moisture, and retrieval of air temperature. Among the satellite TIR sensors in operation, Landsat TIR sensor provides the only feasibility for long-term reconstruction of a LST dataset for environmental applications. However, a holistic technique is not currently available to generate spatially and temporally continuous LSTs from Landsat due to its 16-day revisit frequency, impact of atmospheric conditions and the SLC (Scan Line Corrector) -off gap. Previous algorithms had been developed to overcome these limitations, it is still not possible to generate LSTs at any desired date with consistent accuracy and corrections. Therefore, this study aimed to devise an algorithm to reconstruct consistent, daily LSTs at Landsat spatial resolution based solely on Landsat imagery. By selecting Beijing, China, as the study area, a total of 512 images from 1984 to 2011 were downloaded from the USGS online portal and were consistently calibrated to surface reflectance and brightness temperature. The cloud-, cloud shadow-, and snow-contaminated pixels were excluded according to quality flags; and a further screening procedure based on temporal information of Landsat spectral bands 2, 4, and 5 was conducted. Brightness temperatures were converted to LSTs through the single channel algorithm with input of water vapor from the NCEP Reanalysis dataset. Field LSTs were collected from 11 weather stations in Beijing in the year of 2008, 2009, and 2010. The proposed algorithm included four modules: Data filtEr, temporaL segmentation, periodic and trend modeling, and GAussian process (DELTA). Accuracy assessment showed that, compared with the in situ LSTs from weather stations, satellite-derived LSTs inverted through the single channel algorithm had an average accuracy of 2.3 K. Further comparison between LSTs reconstructed from the DELTA algorithm and those collected from weather stations in the year 2008 yielded a mean error of 3.5 K. Twelve LST maps reconstructed from the DELTA in 2000 showed that LSTs of different land covers exhibited similar seasonal patterns and reached their maximal values in June/July. Using LST of every August 15th as an example, the SUHI (surface urban heat island) intensity of Beijing was computed, which ranged from 3.3 K to 5.3 K from 1984 to 2011, with an increase pattern of LST in both rural and urban areas. © 2016 Elsevier Inc.


Xia H.,Chinese University of Hong Kong | Liu D.,Chinese University of Hong Kong | Song K.,South China Normal University | Miao Q.,Chinese University of Hong Kong
Chemical Science | Year: 2011

This study explores a bifunctional hydrocarbon, which has two non-planar dibenzocycloheptatriene moieties linked by three cumulative C-C double bonds. This flexible conjugated molecule can adopt two conformations, namely, syn and anti, in its crystals. Of particular interest is that the molecule's solids not only function as p-type semiconductors with field effect mobility of 0.02 cm2 V-1 S-1 but also exhibit vapochromic behavior with high selectivity. Upon selectively trapping specific volatile molecules, such as toluene and m-xylene, in the crystal lattice, the guest-free crystals of the syn conformer change to the clathrate crystals of the anti conformer accompanied by a change of color from red to orange. The unique combination of the two useful functions of this molecule can be attributed to its cycloheptatriene and cumulene moieties, both of which have rarely been used in building blocks for organic functional materials. This journal is © The Royal Society of Chemistry 2011.


Vatamanu J.,University of Utah | Xing L.,South China Normal University | Li W.,South China Normal University | Bedrov D.,University of Utah
Physical Chemistry Chemical Physics | Year: 2014

In this work using molecular dynamics simulations we examine the temperature dependence of the differential capacitance of room temperature ionic liquid electrolytes near electrified surfaces. For electrodes with atomically flat surfaces our simulations show very weak temperature dependence of the differential capacitance (DC) with a slight decrease of DC with increasing temperature. For atomically corrugated surfaces where the ion dimensions are comparable to the size of the surface corrugation patterns, the influence of temperature on DC is much more pronounced. At low temperatures the DC dependence on electrode potential shows large variations with well-defined maxima and minima. However, with increasing temperature these features are significantly flattened. Also for these corrugated surfaces an abnormal positive slope of DC vs. temperature is observed in the narrow range of relatively low voltages. Analysis of changes in the electric double layer structure as a function of temperature allowed us to propose a new mechanism explaining the observed trends in capacitance as a function of temperature and surface topography. The obtained simulation results are discussed in light of available experimental data and help to discriminate between contradictory experimentally observed trends in DC temperature dependence reported for ionic liquid based electrolytes in the literature. © 2014 the Owner Societies.


Liu C.,South China Normal University | Luo H.,South China Normal University | Shi G.,South China Normal University | Yang J.,South China Normal University | And 2 more authors.
Journal of Materials Chemistry C | Year: 2015

A carbazole functionalized AIE molecule was constructed and applied as a precursor to prepare the luminescent network films for organic light-emitting devices (OLEDs) by electrochemical polymerization. The resultant cross-linked electrochemically polymerized films have smooth surface and exhibit high thermal stability. OLEDs with these films as light emitting layer have a maximum luminance of 489 cd m-2, a maximum luminance efficiency of 0.38 cd A-1, and a turn-on voltage of 3.4 V. These results indicate that electrochemical synthesis can be a new facile route for constructing the cross-linked polymer luminescent films with AIE molecules, which show potential applications in OLEDs. © 2015 The Royal Society of Chemistry.


Hu S.,Guangdong University of Petrochemical Technology | Hu S.,South China Normal University | Hu W.,South China Normal University
Physica B: Condensed Matter | Year: 2013

We reported the existence and stability of defect solitons in saturable nonlinearity media with parity-time (PT) symmetric optical lattices. Families of fundamental and dipole solitons are found in the semi-infinite gap and the first gap. The power of solitons increases with the increasing of the propagation constant and saturation parameter. The existence areas of fundamental and dipole solitons shrink with the growth of saturation parameter. The instability of dipole solitons for positive and no defect induced by the imaginary part of PT symmetric potentials can be suppressed by the saturation nonlinearity, but for negative defect it cannot be suppressed by the saturation nonlinearity. © 2013 Elsevier B.V.


Wang Y.,South China Normal University | Xing L.,South China Normal University | Li W.,South China Normal University | Bedrov D.,University of Utah
Journal of Physical Chemistry Letters | Year: 2013

Sulfone-based electrolytes have attracted a great attention due to their high oxidation stability comparing to conventional carbonates. However, the ab initio calculated oxidation potentials (Eox) of isolated sulfones are lower than those for carbonates. To understand this contradiction, the oxidations of three carbonates and eleven sulfones in a presence of anions and other solvent molecules have been investigated by the density functional theory calculations with a polarized continuum model. Importantly, we found that the Eox of some of the sulfones show surprisingly high stability toward the presence of anions and another solvent, which is the key factor of high oxidation stability of these electrolytes compared to carbonates. Finally, the way to design new high oxidation stability sulfones by modifying their functional groups is discussed. © 2013 American Chemical Society.


Hu S.,South China Normal University | Hu S.,Guangdong University of Petrochemical Technology | Ma X.,South China Normal University | Lu D.,South China Normal University | And 2 more authors.
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

The existence and stability of defect solitons in parity-time (PT) symmetric optical lattices with nonlocal nonlinearity are reported. It is found that nonlocality can expand the stability region of defect solitons. For positive or zero defects, fundamental and dipole solitons can exist stably in the semi-infinite gap and the first gap, respectively. For negative defects, fundamental solitons can be stable in both the semi-infinite gap and the first gap, whereas dipole solitons are unstable in the first gap. There exist a maximum degree of nonlocal nonlinearity, above which the fundamental solitons in the semi-infinite gap and the dipole solitons in the first gap do not exist for negative defects. The influence of the imaginary part of the PT-symmetric potentials on soliton stability is given. When the modulation depth of the PT-symmetric lattices is small, defect solitons can be stable for positive and zero defects, even if the PT-symmetric potential is above the phase transition point. © 2012 American Physical Society.


Hu S.,Guangdong University of Petrochemical Technology | Hu S.,South China Normal University | Hu W.,South China Normal University
Optics Communications | Year: 2013

The existence and stability of defect solitons in parity-time (PT) symmetric optical lattices with self-defocusing nonlinearity are reported. It is found that various solitons can exist in different gaps for different defects. All of the solitons have real and imaginary parts of opposite parities. For positive defects, fundamental and multipole solitons can exist stably in the semi-infinite gap and the first gap, respectively. For zero or negative defects, fundamental and multipole solitons can exist stably in the first gap and the second gap, respectively. For solitons with positive and negative defects, there exists a cutoff point of the propagation constant above which the defect solitons vanish. The relation with the cutoff point and the depth of PT potentials is studied. The influence of the imaginary part of the PT-symmetric potentials on soliton stability is given. Crown Copyright © 2013 Published by Elsevier B.V. All rights reserved.


Huang L.,Chinese University of Hong Kong | Mo L.,South China Normal University | Li Y.,Zhengzhou University
Journal of Experimental Psychology: Human Perception and Performance | Year: 2012

A large part of the empirical research in the field of visual attention has focused on various concrete paradigms. However, as yet, there has been no clear demonstration of whether or not these paradigms are indeed measuring the same underlying construct. We collected a very large data set (nearly 1.3 million trials) to address this question. We tested 257 participants on nine paradigms: conjunction search, configuration search, counting, tracking, feature access, spatial pattern, response selection, visual short-term memory, and change blindness. A fairly general attention factor was identified. Some of the participants were also tested on eight other paradigms. This general attention factor was found to be correlated with intelligence, visual marking, task switching, mental rotation, and Stroop task. On the other hand, a few paradigms that are very important in the attention literature (attentional capture, consonance-driven orienting, and inhibition of return) were found to be dissociated from this general attention factor. © 2012 American Psychological Association.


Jiang L.,South China Normal University | Jiang L.,Chinese University of Hong Kong | Wang Y.,Jinan University | Li Q.-F.,Chinese University of Hong Kong | And 3 more authors.
Cell Research | Year: 2012

UV-B (280-315nm) is an integral part of solar radiation and can act either as a stress inducer or as a developmental signal. In recent years, increasing attention has been paid to the low-fluence UV-B-induced photomorphogenic response and several key players in this response have been identified, which include UVR8 (a UV-B-specific photoreceptor), COP1 (a WD40-repeat-containing RING finger protein), HY5 (a basic zipper transcription factor), and RUP1/2 (two UVR8-interacting proteins). Here we report that Arabidopsis SALT TOLERANCE (STO/BBX24), a known regulator for light signaling in plants, defines a new signaling component in UV-B-mediated photomorphogenesis. The bbx24 mutant is hypersensitive to UV-B radiation and becomes extremely dwarfed under UV-B treatment. By contrast, BBX24 overexpression transgenic lines respond much more weakly to UV-B than the bbx24 and wild-type plants. BBX24 expression is UV-B-inducible and its accumulation under UV-B requires COP1. Co-immunoprecipitation experiments indicate that BBX24 interacts with COP1 in planta upon UV-B illumination. Moreover, BBX24 interacts with HY5 and acts antagonistically with HY5 in UV-B-induced inhibition of hypocotyl elongation. Furthermore, BBX24 attenuates UV-B-induced HY5 accumulation and suppresses its transcription-activation activity. Taken together, our results reveal a previously uncharacterized function of the light-regulated BBX24 in UV-B responses and demonstrate that BBX24 functions as a negative regulator of photomorphogenic UV-B responses by interacting with both COP1 and HY5. The UV-B-inducible expression pattern and its suppression of HY5 activity suggest that BBX24 could be a new component of the feedback regulatory module of UV-B signaling in plants. © 2012 IBCB, SIBS, CAS All rights reserved.