Huainan, China
Huainan, China

Anhui University of Science and Technology one of the five key universities in Anhui Province, China. It is situated in Huainan City, Anhui Province, which is also known as a green city and as a base of science and education in China. Covering a land area of 1,300 mu, the university is divided into three branches. Wikipedia.

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Chen D.,Nanjing Forestry University | Zhou J.,Nanjing Forestry University | Zhang Q.,Nanjing Forestry University | Zhu X.,Anhui University of Science and Technology
Renewable and Sustainable Energy Reviews | Year: 2014

Bio-oil is the liquid product of the fast pyrolysis of biomass. Recently, bio-oil has gained increasing attention for its direct use in combustion within boilers and furnaces as well as its use in automobiles and chemical materials after refining. Unfortunately, the composition of bio-oil is very complex. Aging occurs during storage, which leads to obvious changes in the physical and chemical properties of the oil. The poor storage stability of bio-oil restricts its extensive applications as a key renewable energy alternative. Viscosity and average molecular weight, as well as water and solid content can measured to determine changes in bio-oil. In this article, the testing parameters and technologies used for examining bio-oil stability and research progress in the field of bio-oil stability are reviewed. Emphasis is placed on thermal and oxidation stability. Scientific and technical developments towards improving bio-oil stability are also discussed. Furthermore, important aspects for consideration when developing experimental plans for bio-oil upgrades are examined. It also points out challenges to success with bio-oil upgrading in the future. © 2014 Elsevier Ltd.

Zhang C.,National University of Singapore | Yu S.,National University of Singapore | Yu S.,Anhui University of Science and Technology | Chen Q.,National University of Singapore | Oh C.H.,National University of Singapore
Physical Review Letters | Year: 2013

Entanglement detection and estimation are fundamental problems in quantum information science. Compared with discrete-variable states, for which lots of efficient entanglement detection criteria and lower bounds of entanglement measures have been proposed, the continuous-variable entanglement is much less understood. Here we shall present a family of entanglement witnesses based on continuous-variable local orthogonal observables (CVLOOs) to detect and estimate entanglement of Gaussian and non-Gaussian states, especially for bound entangled states. By choosing an optimal set of CVLOOs, our entanglement witness is equivalent to the realignment criterion and can be used to detect bound entanglement of a class of 2+2 mode Gaussian states. Via our entanglement witness, lower bounds of two typical entanglement measures for arbitrary two-mode continuous-variable states are provided. © 2013 American Physical Society.

Zheng Z.,Anhui University of Science and Technology | Gong M.,University of Texas at Dallas | Zou X.,Anhui University of Science and Technology | Zhang C.,University of Texas at Dallas | Guo G.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase was first predicted in two-dimensional superconductors about 50 years ago, but so far unambiguous experimental evidence is still lacking. The recently experimentally realized spin-imbalanced Fermi gases may potentially unveil this elusive state, but they require very stringent experimental conditions. In this Rapid Communication, we show that FFLO phases may be observed even in a three-dimensional (3D) degenerate Fermi gas with spin-orbit coupling and an in-plane Zeeman field. The FFLO phase is driven by the interplay between the asymmetry of the Fermi surface and the superfluid order, instead of the interplay between magnetic and superconducting order in solid materials. The predicted FFLO phase exists in a giant parameter region, possesses a stable long-range superfluid order due to the 3D geometry, and can be observed with an experimentally already achieved temperature (T∼0.05EF), thus opening a fascinating avenue for exploring FFLO physics. © 2013 American Physical Society.

Xiao Y.-F.,Peking University | Zou C.-L.,Anhui University of Science and Technology | Li B.-B.,Peking University | Li Y.,Peking University | And 3 more authors.
Physical Review Letters | Year: 2010

We propose a kind of plasmonic whispering-gallery mode highly localized on the exterior surface of a metal-coated microresonator. This exterior (EX) surface mode possesses high quality factors at room temperature, and can be efficiently excited by a tapered fiber. The EX mode can couple to an interior (IN) mode and this coupling produces a strong anticrossing behavior, which not only allows conversion of IN to EX modes, but also forms a long-lived antisymmetric mode. As a potential application, the EX mode could be used for a biosensor with a sensitivity high of up to 500 nm per refraction index unit, a large figure of merit, and a wide detection range.

Zhang S.-L.,Anhui University of Science and Technology | Zhou Z.-W.,Anhui University of Science and Technology | Wu B.,Peking University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We study theoretically the superfluidity and stability of a Bose-Einstein condensate (BEC) whose interatomic scattering length is periodically modulated with optical Feshbach resonance. Our numerical study finds that the properties of this periodic BEC are strongly influenced by the modulation strength. When the modulation strength is small, only the Bloch waves close to the Brillouin zone edge suffer both Landau and dynamical instabilities. When the modulation strength is strong enough, all Bloch waves become dynamically unstable. In other words, the periodic BEC loses its superfluidity completely. © 2013 American Physical Society.

Wang Z.,Anhui University of Science and Technology | Feng J.,National University of Singapore | Yan S.,National University of Singapore
International Journal of Computer Vision | Year: 2015

How to generate robust image representations, when there is contamination from noisy pixels within the images, is critical for boosting the performance of image classification methods. However, such an important problem is not fully explored yet. In this paper, we propose a novel image representation learning method, i.e., collaborative linear coding (CLC), to alleviate the negative influence of noisy features in classifying images. Specifically, CLC exploits the correlation among local features in the coding procedure, in order to suppress the interference of noisy features via weakening their responses on coding basis. CLC implicitly divides the extracted local features into different feature subsets, and such feature allocation is indicated by the introduced latent variables. Within each subset, the features are ensured to be highly correlated, and the produced codes for them are encouraged to activate on the identical basis. Through incorporating such regularization in the coding model, the responses of noisy local features are dominated by the responses of informative features due to their rarity compared with the informative features. Thus the final image representation is more robust and distinctive for following classification, compared with the coding methods without considering such high order correlation. Though CLC involves a set of complicated optimization problems, we investigate the special structure of the problems and then propose an efficient alternative optimization algorithm. We verified the effectiveness and robustness of the proposed CLC on multiple image classification benchmark datasets, including Scene 15, Indoor 67, Flower 102, Pet 37, and PASCAL VOC 2011. Compared with the well established baseline LLC, CLC consistently enhances the classification accuracy, especially for the images containing more noises. © 2014, Springer Science+Business Media New York.

Wang C.B.,Anhui University of Science and Technology
Astrophysical Journal | Year: 2015

A scenario based on electron cyclotron maser (ECM) emission is proposed for the fine structures of solar radio emission. It is suggested that under certain conditions modulation of the ratio between the plasma frequency and electron gyro frequency by ultra-low-frequency waves, which is a key parameter for excitation of ECM instability, may lead to the intermittent emission of radio waves. As an example, the explanation for the observed fine-structure components in the solar Type IIIb bursts is discussed in detail. Three primary issues of Type IIIb bursts are addressed: (1) the physical mechanism that results in intermittent emission elements that form a chain in the dynamic spectrum of Type IIIb bursts, (2) the cause of split pairs (or double stria) and triple stria, and (3) why only IIIb-III bursts are observed in the events of fundamental harmonic pair emission whereas IIIb-IIIb or III-IIIb bursts are very rarely observed. © 2015. The American Astronomical Society. All rights reserved.

Wang Z.F.,Anhui University of Science and Technology | Wang Z.F.,University of Utah | Liu F.,University of Utah
Physical Review Letters | Year: 2015

Graphene, the first discovered 2D Dirac material, has had a profound impact on science and technology. In the last decade, we have witnessed huge advances in graphene related fundamental and applied research. Here, based on first-principles calculations, we propose a new 2D Dirac band on the Si(111) surface with 1/3 monolayer halogen coverage. The sp3 dangling bonds form a honeycomb superstructure on the Si(111) surface that results in an anisotropic Dirac band with a group velocity (∼106m/s) comparable to that in graphene. Most remarkably, the Si-based surface Dirac band can be used to excite a tunable THz plasmon through electron-hole doping. Our results demonstrate a new way to design Dirac states on a traditional semiconductor surface, so as to make them directly compatible with Si technology. We envision this new type of Dirac material to be generalized to other semiconductor surfaces with broad applications. © 2015 American Physical Society. © 2015 American Physical Society.

Chen N.,Anhui University of Science and Technology | Li J.,University of Adelaide | Liu Y.,Beijing University of Technology | Liu Z.,Tsinghua University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

The LHC searches for the CP-odd Higgs boson A are studied (with masses from 300 GeV to 1 TeV) in the context of the general two-Higgs-doublet model. With the discovery of the 125 GeV Higgs boson at the LHC, we highlight one promising discovery channel of A→hZ. This channel can become significant for a heavy CP-odd Higgs boson after the global signal fitting to the 125 GeV Higgs boson in the general two-Higgs-doublet model. It is particularly interesting in the scenario where two CP-even Higgs bosons in the two-Higgs-doublet model have the common mass of 125 GeV. Since the final states involve a standard-model-like Higgs boson, we apply the jet substructure analysis of tagging the fat Higgs jet in order to eliminate the standard-model background sufficiently. After performing the kinematic cuts, we present the LHC search sensitivities for the CP-odd Higgs boson with mass up to 1 TeV via this channel. © 2015 American Physical Society.

Zhang Y.,Anhui University of Science and Technology | Zheng F.,Anhui University of Science and Technology | Yang T.,Anhui University of Science and Technology | Zhou W.,Anhui University of Science and Technology | And 8 more authors.
Nature Materials | Year: 2012

The induction of autophagy on exposure of cells to a variety of nanoparticles represents both a safety concern and an application niche for engineered nanomaterials. Here, we show that a short synthetic peptide, RE-1, identified by means of phage display, binds to lanthanide (LN) oxide and upconversion nanocrystals (UCN), forms a stable coating layer on the nanoparticlesĝ™ surface, and effectively abrogates their autophagy-inducing activity. Furthermore, RE-1 peptide variants exhibit a differentially reduced binding capability, and correspondingly, a varied ability to reduce the autophagic response. We also show that the addition of an arginineg-glycineg-aspartic acid (RGD) motif to RE-1 enhances autophagy for LN UCN through the interaction with integrins. RE-1 and its variants provide a versatile tool for tuning materialg-cell interactions to achieve the desired level of autophagy, and may prove useful for the various diagnostic and therapeutic applications of LN-based nanomaterials and nanodevices. © 2012 Macmillan Publishers Limited. All rights reserved.

Zhu F.,Anhui University of Science and Technology | Wang Z.-X.,Anhui University of Science and Technology
Organic Letters | Year: 2015

Palladium-catalyzed cross-coupling via the Csp 2-S bond activation of aryl thioethers and the C-H bond activation of azoles or thiazoles was carried out. Electron-deficient and -rich aryl methyl thioethers and diaryl thioethers can be employed as the coupling partners and the reaction tolerates a range of functional groups including MeO, CF3, CN, PhCO, CONEt2, and Py groups. © 2015 American Chemical Society.

Dong G.,Zhejiang Normal University | Lin X.,Zhejiang Normal University | Zhou H.,Zhejiang Normal University | Lu Q.,Anhui University of Science and Technology

Internet addiction disorder (IAD) has raised widespread public health concerns. In this study, we explored the cognitive flexibility in IAD subjects using a color-word Stroop task. Behavioral and imaging data were collected from 15 IAD subjects (21.2. ±. 3.2. years) and 15 healthy controls (HC, 22.1. ±. 3.6. years). Group comparisons found that IAD subjects show higher superior temporal gyrus activations than healthy controls in switching (easy to difficult; difficult to easy) than in repeating trials. In addition, in difficult-to-easy situation, IAD subjects show higher brain activation in bilateral insula than healthy controls; in easy-to-difficult situation, IAD subjects show higher brain activation in bilateral precuneus than healthy controls. Correlations were also performed between behavioral performances and brain activities in relevant brain regions. Taken together, we concluded that IAD subjects engaged more endeavors in executive control and attention in the switching task. From another perspective, IAD subjects show impaired cognitive flexibilities. © 2013 Elsevier Ltd.

Wang J.,Jiangsu University | Wang J.,Anhui University of Science and Technology | Wang J.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Chen K.,Jiangsu University | And 3 more authors.
Nano Letters | Year: 2013

The catalytic mechanism offers an efficient tool to produce crystalline semiconductor nanowires, in which the choice, state, and structure of catalysts are active research issues of much interest. Here we report a novel solution-solid-solid (SSS) mechanism for nanowire growth catalyzed by solid-phase superionic conductor nanocrystals in low-temperature solution. The preparation of Ag2Se-catalyzed ZnSe nanowires at 100-210 C is exampled to elucidate the SSS model, which can be extendable to grow other II-VI semiconductor (e.g., CdSe, ZnS, and CdS) nanowires by the catalysis of nanoscale superionic-phase silver or copper(I) chalcogenides (Ag2Se, Ag2S, and Cu2S). The exceptional catalytic ability of these superionic conductors originates from their structure characteristics, known for high-density vacancies and fast mobility of silver or copper(I) cations in the rigid sublattice of Se2- or S2- ions. Insights into the SSS mechanism are provided based on the formation of solid solution and the solid-state ion diffusion/transport at solid-solid interface between catalyst and nanowire. © 2013 American Chemical Society.

Yu X.-F.,Anhui University of Science and Technology | Zhang C.,Anhui University of Science and Technology | Zhang C.,Beijing Normal University | Wang Z.-X.,Anhui University of Science and Technology
Organometallics | Year: 2013

The synthesis and characterization of N,N,O-chelate zinc enolate complexes and the catalysis of the complexes for the ROP of rac-lactide are reported. The pyrazole-based ligand precursors o-(3,5-Me2C3HN 2)C6H4N=C(Me)CH=C(OH)R1 (R 1 = Me, 1; R1 = Ph, 2; R1 = t-Bu, 3; R 1 = CF3, 4)were synthesized by reaction of 2-(3,5-dimethyl-1H-pyrazol-1-yl)benzenamine with 1,3-diketones, including pentane-2,4-dione,1-phenylbutane-1,3-dione, 5,5-dimethylhexane-2,4-dione, and 1,1,1-trifluoropentane-2,4-dione. Treatment of 1-4 with ZnEt2 generated the N,N,O-coordinated zinc complexes [Zn(Et){o-(OC(R 1)=CHC(Me)=N)C6H4(3,5-Me2C 3HN2)}] (R1 = Me, 5; R1 = Ph, 6; R1 = t-Bu, 7; R1 = CF3, 8). The iminophosphoranyl-moiety-containing ligand precursors o-(3,5-Me 2C3HN2)C6H4N=P(Ph 2)CH2C(O)R2 (R2 = Ph, 9; R 2 = t-Bu, 10) were synthesized by reaction of 1-(2-azidophenyl)-3,5- dimethyl-1H-pyrazole with 1-phenyl-2-(diphenylphosphino)ethanone and 3,3-dimethyl-1-(diphenylphosphino)butan-2-one, respectively. Treatment of 9 and 10 with ZnEt2 afforded the zinc complexes [Zn(Et){o-(OC(R 2)=CHP(Ph2)=N)C6H4(3,5-Me 2C3HN2)}] (R2 = Ph, 11; R 2 = t-Bu, 12). The ligand precursors and complexes were characterized by NMR spectroscopy and elemental analyses. Complexes 5 and 11 were also characterized by single-crystal X-ray diffraction techniques. In the presence of BnOH complexes 5-8 efficiently catalyzed the ring-opening polymerization of rac-lactide in a controlled fashion, whereas complexes 11 and 12 showed much lower catalytic activity under the same conditions. © 2013 American Chemical Society.

Yu S.,National University of Singapore | Yu S.,Anhui University of Science and Technology | Oh C.H.,National University of Singapore
Physical Review Letters | Year: 2012

Quantum contextuality, as proved by Kochen and Specker, and also by Bell, should manifest itself in any state in any system with more than two distinguishable states and recently has been experimentally verified. However, for the simplest system capable of exhibiting contextuality, a qutrit, the quantum contextuality is verified only state dependently in experiment because too many (at least 31) observables are involved in all the known state-independent tests. Here we report an experimentally testable inequality involving only 13 observables that is satisfied by all noncontextual realistic models while being violated by all qutrit states. Thus our inequality facilitates a state-independent test of the quantum contextuality for an indivisible quantum system. We also provide a record-breaking state-independent proof of the Kochen-Specker theorem with 13 directions determined by 26 points on the surface of a magic cube. © 2012 American Physical Society.

Yu S.,National University of Singapore | Yu S.,Anhui University of Science and Technology | Chen Q.,National University of Singapore | Zhang C.,National University of Singapore | And 2 more authors.
Physical Review Letters | Year: 2012

We show that a single Bell's inequality with two dichotomic observables for each observer, which originates from Hardy's nonlocality proof without inequalities, is violated by all entangled pure states of a given number of particles, each of which may have a different number of energy levels. Thus Gisin's theorem is proved in its most general form from which it follows that for pure states Bell's nonlocality and quantum entanglement are equivalent. © 2012 American Physical Society.

Zhou S.,Fujian Normal University | Xu J.-M.,Anhui University of Science and Technology
Information Sciences | Year: 2013

The growing size of the multiprocessor system increases its vulnerability to component failures. It is crucial to locate and to replace the faulty processors to maintain a system's high reliability. The fault diagnosis is the process of identifying faulty processors in a system through testing. In this paper, we show that the largest connected component of the survival graph contains almost all of the remaining vertices in the (n, k)-arrangement graph An,k when the number of moved faulty vertices is up to twice or three times the traditional connectivity. Using this fault resiliency, we establish the conditional diagnosability of An,k under the comparison model, and prove that the conditional diagnosability of An,k is (3k - 2)(n - k) - 3 for k ≥ 4, n ≥ k + 2; and the conditional diagnosability of A n,n-1 is 3n - 7 for n ≥ 5. © 2013 Elsevier Inc. All rights reserved.

Lu D.,Anhui University of Science and Technology | Xu N.,Anhui University of Science and Technology | Xu R.,Anhui University of Science and Technology | Chen H.,Anhui University of Science and Technology | And 2 more authors.
Physical Review Letters | Year: 2011

Quantum simulation can beat current classical computers with minimally a few tens of qubits. Here we report an experimental demonstration that a small nuclear-magnetic-resonance quantum simulator is already able to simulate the dynamics of a prototype laser-driven isomerization reaction using engineered quantum control pulses. The experimental results agree well with classical simulations. We conclude that the quantum simulation of chemical reaction dynamics not computable on current classical computers is feasible in the near future. © 2011 American Physical Society.

Deng L.,U.S. Food and Drug Administration | Luo M.,University of Maryland Institute for Bioscience and Biotechnology Research | Luo M.,Anhui University of Science and Technology | Velikovsky A.,University of Maryland Institute for Bioscience and Biotechnology Research | And 3 more authors.
Annual Review of Biophysics | Year: 2013

The adaptive immune system, which is based on highly diverse antigen receptors that are generated by somatic recombination, arose approximately 500 Mya at the dawn of vertebrate evolution. In jawed vertebrates, adaptive immunity is mediated by antibodies and T cell receptors (TCRs), which are composed of immunoglobulin (Ig) domains containing hypervariable loops that bind antigen. In striking contrast, the adaptive immune receptors of jawless vertebrates, termed variable lymphocyte receptors (VLRs), are constructed from leucine-rich repeat (LRR) modules. Structural studies of VLRs have shown that these LRR-based receptors bind antigens though their concave surface, in addition to a unique hypervariable loop in the C-terminal LRR capping module. These studies have revealed a remarkable example of convergent evolution in which jawless vertebrates adopted the LRR scaffold to recognize as broad a spectrum of antigens as the Ig-based antibodies and TCRs of jawed vertebrates, with altogether comparable affinity and specificity. Copyright © 2013 by Annual Reviews.

Zhao K.,Central China Normal University | Zhang L.,Central China Normal University | Wang J.,Anhui University of Science and Technology | Li Q.,Anhui University of Science and Technology | And 2 more authors.
Journal of the American Chemical Society | Year: 2013

We demonstrate that BiOCl single-crystalline nanosheets possess surface structure-dependent molecular oxygen activation properties under UV light. The (001) surface of BiOCl prefers to reduce O2 to ·O 2 - through one-electron transfer, while the (010) surface favors the formation of O2 2- via two-electron transfer, which is cogoverned by the surface atom exposure and the situ generated oxygen vacancy characteristics of the (001) and (010) surfaces under UV light irradiation. © 2013 American Chemical Society.

Migani A.,University of the Basque Country | Migani A.,Catalan Institute of Nanoscience and Nanotechnology | Mowbray D.J.,University of the Basque Country | Iacomino A.,University of the Basque Country | And 3 more authors.
Journal of the American Chemical Society | Year: 2013

Photocatalytic activity depends on the optimal alignment of electronic levels at the molecule-semiconductor interface. Establishing the level alignment experimentally is complicated by the uncertain chemical identity of the surface species. We address the assignment of the occupied and empty electronic levels for the prototypical photocatalytic system consisting of methanol on a rutile TiO2(110) surface. Using many-body quasiparticle (QP) techniques, we show that the frontier levels measured in UV photoelectron and two-photon photoemission spectroscopy experiments can be assigned to molecularly chemisorbed methanol rather than its dissociated product, the methoxy species. We find that the highest occupied molecular orbital of the methoxy species is much closer to the valence band maximum, suggesting why it is more photocatalytically active than the methanol molecule. We develop a general semiquantitative model for predicting many-body QP energies based on the electronic screening within the bulk, molecular, or vacuum regions of the wave functions at molecule-semiconductor interfaces. © 2013 American Chemical Society.

Zhang W.,Peking University | Zhang Z.,Anhui University of Science and Technology | Chen X.,Anhui University of Science and Technology
Geophysical Journal International | Year: 2012

Surface topography has been considered a difficult task for seismic wave numerical modelling by the finite-difference method (FDM) because the most popular staggered finite-difference scheme requires a rectilinear grid. Even though there are numerous collocated grid schemes in other computational fields that could be used to solve the first-order hyperbolic equations, the lack of a stable free-surface boundary condition implementation for curvilinear grids also obstructs the adoption of curvilinear grids in seismic wave FDM modelling. In this study, we use generalized curvilinear grids that can fit the surface topography to discretize the computational domain and describe the implementation of a collocated grid finite-difference scheme, a higher order MacCormack scheme, to solve the first-order hyperbolic velocity-stress equations on the curvilinear grid. To achieve a sufficiently accurate and stable free-surface boundary condition implementation on the curvilinear grids, we propose the traction image method that antisymmetrically images the traction components instead of the stress components to the ghost points above the free surface. Since the velocity derivatives at the free surface are provided by the free-surface condition, we use a compact scheme to compute the velocity derivatives near the free surface and avoid the use of velocity values on the ghost points. Numerical tests verify that using the curvilinear grid, the collocated finite-difference scheme and the traction image technique can simulate seismic wave propagation in the presence of surface topography with sufficient accuracy. © 2012 The Authors Geophysical Journal International © 2012 RAS.

Ye H.,Anhui University of Science and Technology | Long L.,Anhui University of Science and Technology | Zhang H.,Anhui University of Science and Technology | Zou R.,Peking University
Applied Energy | Year: 2014

The performance of a kind of shape-stabilized phase change material (PCM) was demonstrated in the Testing and Demonstration Platform for Building Energy Research. The results indicate that the use of PCM could lower the indoor temperature fluctuation and slow the indoor temperature's decline rate. The PCM's performance was also simulated in BuildingEnergy, a modeling software developed by the authors and validated via experiments, and evaluated via energy saving index (ESI), an evaluation index presented by the authors. The ESI is the ratio of a particular material or component's energy saving equivalent (ESE) to the corresponding value of the ideal material or component that can maintain the room at an ideal thermal state in passive mode, where the ESE represents the hypothetical energy that should be input to maintain a passive room at the same thermal state as that when a particular material or component is adopted. The ESI can be used to characterize the performance of an actual building material or component from a common standpoint and be used to evaluate the performance of materials or components in different climatic regions or under different operating situations. The performance of the insulation material, represented by expanded polystyrene (EPS), was also simulated to give a comparison. The results show that the PCM has a better performance in the summer and a worse performance in the winter, while the EPS has a better performance over an entire year. © 2013 Elsevier Ltd.

Wang Y.,National University of Singapore | Shu C.,National University of Singapore | Huang H.B.,Anhui University of Science and Technology | Teo C.J.,National University of Singapore
Journal of Computational Physics | Year: 2015

A multiphase lattice Boltzmann flux solver (MLBFS) is proposed in this paper for incompressible multiphase flows with low- and large-density-ratios. In the solver, the flow variables at cell centers are given from the solution of macroscopic governing differential equations (Navier-Stokes equations recovered by multiphase lattice Boltzmann (LB) model) by the finite volume method. At each cell interface, the viscous and inviscid fluxes are evaluated simultaneously by local reconstruction of solution for the standard lattice Boltzmann equation (LBE). The forcing terms in the governing equations are directly treated by the finite volume discretization. The phase interfaces are captured by solving the phase-field Cahn-Hilliard equation with a fifth order upwind scheme. Unlike the conventional multiphase LB models, which restrict their applications on uniform grids with fixed time step, the MLBFS has the capability and advantage to simulate multiphase flows on non-uniform grids. The proposed solver is validated by several benchmark problems, such as two-phase co-current flow, Taylor-Couette flow in an annulus, Rayleigh-Taylor instability, and droplet splashing on a thin film at density ratio of 1000 with Reynolds numbers ranging from 20 to 1000. Numerical results show the reliability of the proposed solver for multiphase flows with high density ratio and high Reynolds number. © 2014 Elsevier Inc.

Feng C.,Nanyang Technological University | Feng D.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Organic Letters | Year: 2013

Rh(III)-catalyzed direct olefination of arenes with allyl acetate via C-H bond activation is described using N,N-disubstituted aminocarbonyl as the directing group. The catalyst undergoes a redox neutral process, and high to excellent yields of trans-products are obtained. This protocol exhibits a wide spectrum of functionality compatibility because of the simple reaction conditions employed and provides a highly effective synthetic method in the realm of C-H olefination. © 2013 American Chemical Society.

Li Z.,Zhejiang Normal University | Li C.,Zhejiang Normal University | Mei Y.,Zhejiang Normal University | Wang L.,Anhui University of Science and Technology | And 2 more authors.
Nanoscale | Year: 2013

A facile method has been developed to synthesize uniform nanoscale YF 3 architectures. Interestingly, the unique YF3 nanostructure exhibits a flat and rhombic appearance which is formulated through the hierarchical assembly of YF3 nanocrystals along a specific crystalline orientation. Investigations on the formation process suggest that an assembly disassembly process is responsible for the construction of this novel structure. Enabled by doping with different lanthanides ions, the products can exhibit various down- or up-conversion luminescences, showing their potentials in serving as versatile host matrixes. The tunable luminescent properties allow designing effective upconversion photocatalysts when the doped YF3 nanostructures are coated with a TiO2 shell on their surface. In particular, the YF3@TiO2 hybrid structures have the porous nature that is partially inherited from the YF3 architectures, whose high surface-to-volume ratio facilitates their use as photocatalysts. In this article, we have demonstrated that the YF3:Yb,Tm@TiO2 structures exhibit satisfactory photocatalytic activities under the irradiation of both UV and near IR light. As compared with the conventional TiO2 catalysts, the hybrid structures here offer better performance in photocatalysis in the full solar spectrum. It is anticipated that this work provides a new approach to designing photocatalysts with responses to a broader spectral range. © The Royal Society of Chemistry 2013.

Gao S.,Anhui University of Science and Technology | Gao S.,University of Kansas | O'Sullivan M.,Ciena | Hui R.,University of Kansas
Optics Express | Year: 2012

A coherent lidar system based on the measurement of complex optical field is demonstrated for the first time. An electro-optic in-phase/quadrature (I/Q) modulator is used in the lidar transmitter to realize carrier-suppressed complex optical field modulation in which the positive and the negative optical sidebands can carry independent modulation waveforms. A fiber-optic 90° hybrid is used in the lidar receiver for coherent heterodyne detection and to recover the complex optical field. By loading a constant modulation frequency on the lower optical sideband and a wideband linear frequency chirp on the upper sideband, vector velocity and target distance can be measured independently. The wide modulation bandwidth of this lidar system also enabled unprecedented range resolution and the capability of measuring high velocity unambiguously. © 2012 Optical Society of America.

Li C.,Anhui University of Science and Technology | Zhang Y.,Anhui University of Science and Technology | Hu J.,Anhui University of Science and Technology | Cheng J.,University of Illinois at Urbana - Champaign | Liu S.,Anhui University of Science and Technology
Angewandte Chemie - International Edition | Year: 2010

Micellar traffic lights: The title FRET system (FRET=fluorescence resonance energy transfer) consists of one type of donor dye and two types of acceptor dyes. On/off fluorescence switching of the latter two dyes can be controlled by pH changes and light, respectively. This novel type of multicolor luminescent polymeric assembly can act as a ratiometric probe for pH and temperature with tunable sensitivity. (Figure Presented). © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Yin L.,University of Illinois at Urbana - Champaign | Huang X.,University of Illinois at Urbana - Champaign | Xu H.,Anhui University of Science and Technology | Zhang Y.,University of Illinois at Urbana - Champaign | And 3 more authors.

Biodegradable electronics represent an emerging class of technology with potential to provide advanced semiconductor functionality in temporary biomedical implants. This work reported a biodegradable primary battery as a potential power source for these systems, which uses biodegradable metal foils and polyanhydride packages. Monolithically integrating cells yields battery packs with sufficient power to operate conventional light emitting diodes and radio transmitters. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zha W.,Anhui University of Science and Technology | Zha W.,Brookhaven National Laboratory
Nuclear Physics A | Year: 2014

We report the measurements by the STAR Collaboration of J/ψ invariant yields as a function of transverse momentum at mid-rapidity (|. y|. <. 1.0) in p+. p collisions at s=500 GeV, in Au. +. Au collisions at sNN=39, 62.4 and 200 GeV, and in U. +. U collisions at sNN=193 GeV. The centrality, beam energy and collision system dependences of J/ψ production and nuclear modification factors are discussed. We also report the ratio of ψ(2. S) to J/ψ yields in p+. p collisions at s=500 GeV and ϒ{hooked} production in U. +. U collisions at sNN=193 GeV. © 2014 Elsevier B.V.

Yang C.,Anhui University of Science and Technology | Yang C.,Brookhaven National Laboratory
Nuclear Physics A | Year: 2014

We present the direct photon production for 1

Cui X.,CAS Institute of Physics | Yi W.,Anhui University of Science and Technology
Physical Review X | Year: 2014

Borromean rings and Borromean binding, a class of intriguing phenomena as three objects are linked (bound) together while any two of them are unlinked (unbound), widely exist in nature and have been found in systems of biology, chemistry, and physics. Previous studies have suggested that the occurrence of such a binding in physical systems typically relies on the microscopic details of pairwise interaction potentials at short range and is, therefore, nonuniversal. Here, we report a new type of Borromean binding in ultracold Fermi gases with Rashba spin-orbit coupling, which is universal against short-range interaction details, with its binding energy only dependent on the s-wave scattering length and the spin-orbit-coupling strength.We show that the occurrence of this universal Borromean binding is facilitated by the symmetry of the single-particle dispersion under spin-orbit coupling and is, therefore, symmetry selective rather than interaction selective. The state is robust over a wide range of mass ratios between composing fermions, which are accessible by Li-Li, K-K, and K-Li mixtures in cold-atom experiments. Our results reveal the importance of single- particle spectral symmetry in few-body physics and shed light on the emergence of new quantum phases in a many-body system with exotic few-body correlations.

Tian G.,KTH Royal Institute of Technology | Luo Y.,KTH Royal Institute of Technology | Luo Y.,Anhui University of Science and Technology
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

We study electroluminescence from molecules confined in a scanning tunneling microscope based on a recently proposed density-matrix approach. The molecule is treated by a two-state model with each state consisting of a set of vibrational energy levels. The interband transition probabilities are described by Franck-Condon factors as calculated from a harmonic model. The role played by the tunneling electron as well as by the surface plasmon resonance is investigated. The dependence of the electron-tunneling-induced electroluminescence on the temperature, the bias voltage, the coupling strength between the molecule and the electrodes, and the radiative decay rate of the excited state has been systematically studied. It is found that under high temperature, due to the thermally assisted electron tunneling, photon emissions can still be detected when the bias voltage is less than the excitation energy of the molecule. We also find that when the molecule is asymmetrically coupled to the electrodes, electroluminescence does not strictly follow the Franck-Condon distribution. Our simulations also show that the increase of the radiative decay rate of the excited state cannot lead to the hot luminescence from higher vibrational levels. The involvement of the surface plasmon can drastically alter the spectral profiles, resulting in hot luminescence from molecules, when the surface plasmon in a scanning tunneling microscope is of high strength and ultrashort duration. The influence of the strength and the duration of the plasmon pulse on the electroluminescence spectra has been discussed. © 2011 American Physical Society.

Hoffmann L.,Jülich Research Center | Xue X.,Anhui University of Science and Technology | Alexander M.J.,NorthWest Research Inc
Journal of Geophysical Research: Atmospheres | Year: 2013

The main aim of this study is to find and classify hotspots of stratospheric gravity waves on a global scale. The analysis is based on a 9 year record (2003 to 2011) of radiance measurements by the Atmospheric Infrared Sounder (AIRS) aboard NASA's Aqua satellite. We detect gravity waves based on 4.3 mm brightness temperature variances. Our method focuses on peak events, i.e., strong gravity wave events for which the local variance considerably exceeds background levels. We estimate the occurrence frequencies of these peak events for different seasons and time of day and use the results to find local maxima or "hotspots." In addition, we use AIRS radiances at 8.1 mm to simultaneously detect convective events, including deep convection in the tropics and mesoscale convective systems at middle latitudes. We classify the gravity wave sources based on seasonal occurrence frequencies for convection, but also by means of time series analyses and topographic data. Our study reproduces well-known hotspots of gravity waves, e.g., the Andes and the Antarctic Peninsula. However, the high horizontal resolution of the AIRS observations also allows us to locate numerous mesoscale hotspots, which are partly unknown or poorly studied so far. Most of these mesoscale hotspots are found near orographic features like mountain ranges, coasts, lakes, deserts, or isolated islands. This study will help to select promising regions and seasons for future case studies of gravity waves. © 2012. American Geophysical Union.

Fu Q.,Anhui University of Science and Technology | Fu Q.,KTH Royal Institute of Technology | Luo Y.,Anhui University of Science and Technology | Luo Y.,KTH Royal Institute of Technology
ACS Catalysis | Year: 2013

It has been shown in recent experiments that the Cu(111) surface doped by a small amount of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H2 molecules. Here we performed systematic first-principles calculations to investigate the corresponding mechanism. Our results clearly demonstrate that a very small number of Pd atoms in the subsurface layer can effectively reduce the energy barrier of H2 dissociation, making the ensembles composed of the surface and contiguous subsurface Pd atoms as the active sites. The catalytic activity can be further improved if the Pd atoms are doped in the stepped Cu surfaces. The impact of the subsurface Pd atoms comes from an enhanced surface-adsorbate interaction caused by adjusting the electronic structure of the substrate. The important role played by the subsurface atoms offers an efficient approach to finely tune the surface activity by a very limited number of atoms. Our findings should be very useful for understanding and improving the catalytic properties of alloy systems for the industrially important hydrogenation reactions. © 2013 American Chemical Society.

Ding G.-J.,Anhui University of Science and Technology | King S.F.,University of Southampton | Luhn C.,Durham University | Stuart A.J.,University of Southampton
Journal of High Energy Physics | Year: 2013

We construct models of leptons based on S4 family symmetry combined with a generalised CP symmetry HCP . We show how the flavon potential can spontaneously break the symmetry S4 × H CP down to Z2 × HCP v in the neutrino sector, where the choice of preserved CP symmetry HCP v is controlled by free (real) parameters in the flavon potential. We propose two realistic models of this kind, one at the effective level and one at the renormalisable level. Both models predict trimaximal lepton mixing with CP being either fully preserved or maximally broken, with the intermediate possibility forbidden by the structure of the models. © 2013 SISSA, Trieste, Italy.

Ling Q.,Anhui University of Science and Technology | Wen Z.,Shanghai JiaoTong University | Yin W.,Rice University
IEEE Transactions on Signal Processing | Year: 2013

A set of vectors (or signals) are jointly sparse if all their nonzero entries are found on a small number of rows (or columns). Consider a network of agents {i} that collaboratively recover a set of jointly sparse vectors {x (i)} from their linear measurements {y(i)}. Assume that every agent i collects its own measurement y(i) and aims to recover its own vector x(i) taking advantages of the joint sparsity structure. This paper proposes novel decentralized algorithms to recover these vectors in a way that every agent runs a recovery algorithm and exchanges with its neighbors only the estimated joint support of the vectors. The agents will obtain their solutions through collaboration while keeping their vectors' values and measurements private. As such, the proposed approach finds applications in distributed human action recognition, cooperative spectrum sensing, decentralized event detection, as well as collaborative data mining. We use a non-convex minimization model and propose algorithms that alternate between support consensus and vector update. The latter step is based on reweighted ℓq iterations, where q can be 1 or 2. We numerically compare the proposed decentralized algorithms with existing centralized and decentralized algorithms. Simulation results demonstrate that the proposed decentralized approaches have strong recovery performance and converge reasonably fast. © 1991-2012 IEEE.

Zhou L.,CAS Institute of Physics | Cui X.,CAS Institute of Physics | Yi W.,Anhui University of Science and Technology
Physical Review Letters | Year: 2014

We investigate the pairing physics in a three-component Fermi-Fermi mixture, where a few fermionic impurities are immersed in a noninteracting two-component Fermi gas with synthetic spin-orbit coupling (SOC), and interact attractively with one spin species in the Fermi gas. Because of the interplay of SOC and the spin-selective interaction, the molecular state intrinsically acquires a nonzero center-of-mass momentum, which results in a new type of Fulde-Ferrell (FF) pairing in spin-orbit coupled Fermi systems. The existence of the Fermi sea can also lead to the competition between FF-like molecular states with different center-of-mass momenta, which corresponds to a first-order transition between FF phases in the thermodynamic limit. As the interaction strength is tuned, a polaron-molecule transition occurs in the highly imbalanced system, where the boundary varies nonmonotonically with SOC parameters and gives rise to the reentrance of polaron states. The rich physics in this system can be probed using existing experimental techniques. © 2014 American Physical Society.

Devert A.,Anhui University of Science and Technology | Bredeche N.,University Paris - Sud | Schoenauer M.,University Paris - Sud
IEEE Transactions on Evolutionary Computation | Year: 2011

Most works in multicellular artificial ontogeny solve the halting problem by arbitrarily limiting the number of iterations of the developmental process. Hence, the trajectory of the developing organism in the phenotypic space is only required to come close to an accurate solution during a very short developmental period. Because of the well-known opportunism of evolution, there is indeed no reason for the organism to remain close to a good solution in other situations: if the development is continued after the limiting bound; if the environment is perturbed by some noise during the development; if the development takes place in different physical conditions. In order to increase the robustness of the solution against such hazards, a new stopping criterion for the developmental process is proposed, based on the stability of some internal energy of the organism during its development. Such adaptive stopping criterion biases evolution toward solutions in which robustness is an intrinsic property. Experimental results on different French flag problems demonstrate that enforcing stable developmental process makes it possible to produce solutions that not only accurately approximate the target shape, but also demonstrate near-perfect self-healing properties, as well as excellent generalization capabilities. © 2011 IEEE.

Ji Y.,KTH Royal Institute of Technology | Wang B.,Anhui University of Science and Technology | Luo Y.,KTH Royal Institute of Technology | Luo Y.,Anhui University of Science and Technology
Journal of Physical Chemistry C | Year: 2014

The initial step of O2 evolution reaction on a TiO2 surface is a long-standing puzzle. A recent scanning tunneling microscopy experiment showed that the H2O molecule adsorbed on rutile TiO 2(110) surface could decompose under ultraviolet illumination (Tan, S. J.; et al. J. Am. Chem. Soc., 2012, 134, 9978). The underlying reaction mechanism is now examined by our GGA+U study, in which the oxidation of the H2O molecule by both free and trapped holes has been carefully investigated. It is found that the transfer of the hole trapped at the bridge oxygen to the molecule is hindered by the mismatch between the energy and spatial symmetry of the trapped hole orbital and the highest occupied molecule orbital of H2O. The entire oxidation reaction has a high energy barrier and is barely exothermic. In contrast, the oxidation of the molecule by the free hole is energetically more favorable. The free hole is transferred to the H2O molecule via the in-plane oxygen atom when the molecule stays in the transient dissociation state. This mechanism may also be applicable to the photooxidation of other R-OH type molecules adsorbed on the rutile TiO 2(110) surface. © 2013 American Chemical Society.

Liu G.-Q.,CAS Institute of Physics | Po H.C.,Chinese University of Hong Kong | Du J.,Anhui University of Science and Technology | Liu R.-B.,Chinese University of Hong Kong | Pan X.-Y.,CAS Institute of Physics
Nature Communications | Year: 2013

Realistic quantum computing is subject to noise. Therefore, an important frontier in quantum computing is to implement noise-resilient quantum control over qubits. At the same time, dynamical decoupling can protect the coherence of qubits. Here we demonstrate non-trivial quantum evolution steered by dynamical decoupling control, which simultaneously suppresses noise effects. We design and implement a self-protected controlled-NOT gate on the electron spin of a nitrogen-vacancy centre and a nearby carbon-13 nuclear spin in diamond at room temperature, by employing an engineered dynamical decoupling control on the electron spin. Final state fidelity of 0.91(1) is observed in preparation of a Bell state using the gate. At the same time, the qubit coherence time is elongated at least 30 fold. The design scheme does not require the dynamical decoupling control to commute with the qubit interaction and therefore works for general qubit systems. This work marks a step towards implementing realistic quantum computing systems. © 2013 Macmillan Publishers Limited. All rights reserved.

Ling Q.,Anhui University of Science and Technology | Lemmon M.D.,University of Notre Dame
IEEE Transactions on Automatic Control | Year: 2010

This technical note studies the almost sure input-to-state stability of quantized linear systems with bounded noise under nondeterministic feedback dropouts. It proposes a dropout condition which is both necessary and sufficient for stabilizing the quantized linear system at a finite constant bit rate. Sufficiency of that dropout condition is proven by constructing appropriate quantization policies. Note that the obtained dropout condition does not require reliable dropout acknowledgments (ACKs). Moreover, this technical note derives a lower bound on the constant bit rates under which the quantized system is stabilizable. That bound is achievable when dropout ACKs are available. When dropout ACKs are not available, the bound can be achieved in some systems. Simulations are used to verify some of the analytical results. © 2006 IEEE.

Zhu C.,Georgia Institute of Technology | Zhu C.,Nanjing Southeast University | Peng H.-C.,Georgia Institute of Technology | Zeng J.,Anhui University of Science and Technology | And 3 more authors.
Journal of the American Chemical Society | Year: 2012

We describe a synthesis of Au wavy nanowires in an aqueous solution in the presence of cetyltrimethylammonium bromide (CTAB). The resultant Au nanowires automatically separated from the solution and floated at the air/water interface. We investigated the formation mechanism by characterizing the samples obtained at different stages of the synthesis. Both particle attachment and cold welding were found to be involved in the formation of such nanowires. Based on X-ray photoelectron spectroscopy and thermogravimetric analysis, the CTAB molecules adsorbed on the surface of a Au nanostructure went through a change in structure from a bilayer to a monolayer, converting the Au surface from hydrophilic to hydrophobic. As a result, the Au wavy nanowires were driven to the air/water interface during the synthesis. This growth mechanism is potentially extendable to many other systems involving small surfactant molecules. © 2012 American Chemical Society.

Jiang P.,Tsinghua University | Du W.,University of Pennsylvania | Wu M.,Anhui University of Science and Technology
Protein and Cell | Year: 2014

Energy metabolism is significantly reprogrammed in many human cancers, and these alterations confer many advantages to cancer cells, including the promotion of biosynthesis, ATP generation, detoxification and support of rapid proliferation. The pentose phosphate pathway (PPP) is a major pathway for glucose catabolism. The PPP directs glucose flux to its oxidative branch and produces a reduced form of nicotinamide adenine dinucleotide phosphate (NADPH), an essential reductant in anabolic processes. It has become clear that the PPP plays a critical role in regulating cancer cell growth by supplying cells with not only ribose-5-phosphate but also NADPH for detoxification of intracellular reactive oxygen species, reductive biosynthesis and ribose biogenesis. Thus, alteration of the PPP contributes directly to cell proliferation, survival and senescence. Furthermore, recent studies have shown that the PPP is regulated oncogenically and/or metabolically by numerous factors, including tumor suppressors, oncoproteins and intracellular metabolites. Dysregulation of PPP flux dramatically impacts cancer growth and survival. Therefore, a better understanding of how the PPP is reprogrammed and the mechanism underlying the balance between glycolysis and PPP flux in cancer will be valuable in developing therapeutic strategies targeting this pathway. © 2014 The Author(s).

Ling Q.,Anhui University of Science and Technology | Ribeiro A.,University of Pennsylvania
ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings | Year: 2014

This paper develops a decentralized linearized alternating direction method of multipliers (LADMM) that minimizes the sum of local cost functions in a multi-agent network. Through linearizing the local cost functions agents can obtain their local solutions with simple algebraic operations and gradient descent steps. We prove that the algorithm linearly converges to the optimal solution given that the local cost functions are strongly convex and have Lipschitz gradients. The decentralized LADMM has similar computations as the distributed (sub)gradient method but outperforms the latter, which is unable to achieve linear rate of convergence and convergence to the exact optimal solution simultaneously. Compared to its non-linearized counterpart that suffers from high computation burden, the decentralized LADMM has a comparable rate of convergence according to both theoretical analysis and numerical experiments. © 2014 IEEE.

Zheng X.,Anhui University of Science and Technology | Yan Y.,Anhui University of Science and Technology | Yan Y.,Hong Kong University of Science and Technology | Di Ventra M.,University of California at San Diego
Physical Review Letters | Year: 2013

We investigate the real-time current response of strongly correlated quantum dot systems under sinusoidal driving voltages. By means of an accurate hierarchical equations of motion approach, we demonstrate the presence of prominent memory effects induced by the Kondo resonance on the real-time current response. These memory effects appear as distinctive hysteresis line shapes and self-crossing features in the dynamic current-voltage characteristics, with concomitant excitation of odd-number overtones. They emerge as a cooperative effect of quantum coherence - due to inductive behavior - and electron correlations - due to the Kondo resonance. We also show the suppression of memory effects and the transition to classical behavior as a function of temperature. All these phenomena can be observed in experiments and may lead to novel quantum memory applications. © 2013 American Physical Society.

Du W.,Anhui University of Science and Technology | Du W.,University of Pennsylvania | Jiang P.,Anhui University of Science and Technology | Jiang P.,University of Pennsylvania | And 7 more authors.
Nature Cell Biology | Year: 2013

TAp73 is a structural homologue of the pre-eminent tumour suppressor p53. However, unlike p53, TAp73 is rarely mutated, and instead is frequently overexpressed in human tumours. It remains unclear whether TAp73 affords an advantage to tumour cells and if so, what the underlying mechanism is. Here we show that TAp73 supports the proliferation of human and mouse tumour cells. TAp73 activates the expression of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway (PPP). By stimulating G6PD, TAp73 increases PPP flux and directs glucose to the production of NADPH and ribose, for the synthesis of macromolecules and detoxification of reactive oxygen species (ROS). The growth defect of TAp73-deficient cells can be rescued by either enforced G6PD expression or the presence of nucleosides plus an ROS scavenger. These findings establish a critical role for TAp73 in regulating metabolism, and connect TAp73 and the PPP to oncogenic cell growth. © 2013 Macmillan Publishers Limited. All rights reserved.

Ou R.,Anhui University of Science and Technology | Wang Y.,Anhui University of Science and Technology | Wang H.,Monash University | Xu T.,Anhui University of Science and Technology
Desalination | Year: 2013

A series of polyelectrolytes were evaluated as draw solutions for the forward osmosis (FO) process. Such polyelectrolytes were synthesized by copolymerization of N-isopropylacrylamide with different amounts of sodium acrylate. These polyelectrolytes were thermo-sensitive and water soluble. Hot ultrafiltration (HUF) operated at 45. °C and 2. bar was used as a low-energy method to recover the water from the polyelectrolyte draw solutions. The results showed that 4%PNIPAM-SA solution worked best among nine polyelectrolytes in the forward osmosis process and HUF process, and its FO water flux was 0.347. LMH while the feed solution was pure water and its water recovery fraction was 65.2%. © 2013 Elsevier B.V.

Yang J.,Anhui University of Science and Technology | Zhao Y.,CAS Shanghai Institute of Microsystem and Information Technology | Xi H.,Anhui University of Science and Technology
IEEE Transactions on Neural Networks | Year: 2011

In this brief, we consider extracting generalized eigenvectors in parallel for the generalized eigendecomposition problem. The problem is formulated as an optimization problem of minimizing an unconstrained quartic cost function based on the weighted rule. It is shown that the proposed weighted cost function has a unique global minimum, which corresponds to the principal generalized eigenvectors. In order to estimate the principal generalized eigenvector matrix efficiently, we simplify the quartic cost function as a quadric one by making an appropriate approximation, and then derive a fast algorithm for extracting the principal generalized eigenvector in parallel. We also show the application of the proposed algorithm in blind source separation. Numerical simulations are performed, and the results demonstrate the performance of the proposed algorithm. © 2011 IEEE.

Wang Z.,Nanjing Southeast University | Yu Y.,Anhui University of Science and Technology
IIE Transactions (Institute of Industrial Engineers) | Year: 2012

The optimal production control policy (i.e., the hedging point policy) for a single machine and single part-type manufacturing system for the case where the production surplus is accurately known has been reported in the literature. However, the production surplus is often observed inaccurately in practice. Ignoring this inaccuracy in using the optimal policy leads to not only non-robust situations but also high production costs. To consider the effect of the inaccurate observation, robustness of the production control policy is required. The robustness can be evaluated in terms of the difference between the production surplus trajectory under the policy with an inaccurate observation and the trajectory under the policy with an accurate production surplus (i.e., the hedging point policy). A difference of zero is the ideal case; however, this is generally impossible to achieve since the extent of the observation error is generally unknown. This article proposes a new robust production control policy that can give a small difference between the two trajectories. Compared with the hedging point policy, the proposed policy is more insensitive to production surplus inaccuracy in the neighborhood of the hedging point but responds more slowly to a failure of the machine. Simulation studies show that the proposed policy has a better robustness than the hedging point policy for cases where, just as in actual industrial practice, the machine failure time is much shorter than the up time of the machine. In these cases, with an increase in the observation error, the robustness of the proposed policy becomes increasingly better than that for the hedging point policy. © 2012 Taylor & Francis Group, LLC.

Jiang Y.,Nanyang Technological University | Park C.-M.,Ulsan National Institute of Science and Technology | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Organic Letters | Year: 2014

A new strategy to open the 2-allyl-2H-azirines by 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) promotion in metal-free conditions affording 1-azatrienes that in situ electrocyclize to the pyridines in good to excellent yields is reported. The reaction displays a broad substrate scope and good tolerance to a variety of substituents including aryl, alkyl, and heterocyclic groups. In addition, one-pot synthesis of pyridines from oximes via in situ formation of 2H-azirines was achieved. © 2014 American Chemical Society.

Ling Q.,Anhui University of Science and Technology | Ling Q.,Xidian University | Ribeiro A.,University of Pennsylvania
IEEE Transactions on Signal Processing | Year: 2014

This paper develops the application of the alternating direction method of multipliers (ADMM) to optimize a dynamic objective function in a decentralized multi-agent system. At each time slot, agents in the network observe local functions and cooperate to track the optimal time-varying argument of the sum objective. This cooperation is based on maintaining local primal variables that estimate the value of the optimal argument and auxiliary dual variables that encourage proximity with neighboring estimates. Primal and dual variables are updated by an ADMM iteration that can be implemented in a distributed manner whereby local updates require access to local variables and the most recent primal variables from adjacent agents. For objective functions that are strongly convex and have Lipschitz continuous gradients, the distances between the primal and dual iterates to their corresponding time-varying optimal values are shown to converge to a steady state gap. This gap is explicitly characterized in terms of the condition number of the objective function, the condition number of the network that is defined as the ratio between the largest and smallest nonzero Laplacian eigenvalues, and a bound on the drifts of the optimal primal variables and the optimal gradients. Numerical experiments corroborate theoretical findings and show that the results also hold for non-differentiable and non-strongly convex primal objectives. © 2013 IEEE.

Yu Y.,Anhui University of Science and Technology | Yu Y.,Erasmus University Rotterdam | Wang Z.,Nanjing Southeast University | Liang L.,Anhui University of Science and Technology
International Journal of Production Economics | Year: 2012

Fast deteriorating raw materials such as raw milk, fruit and vegetables are commonly used to produce slowly deteriorating finished products such as milk powders, cheeses, and pastas. This paper studies a Vendor Managed Inventory (VMI) type supply chain where the manufacturing vendor decides how to manage the system-wide inventories of its fast deteriorating raw material and its slowly deteriorating product. The decision variables are a common replenishment cycle of the product and the replenishment frequency of the raw material. We assume the deteriorating rates are known constants and every retailers demand is deterministic. We develop an integrated model to calculate the total inventory and deterioration cost for such a system. We prove the convexity of the cost functions, and based on this a golden search algorithm is developed to find the optimal solution of the model. Our numerical results show that the deteriorating rate of the product may increase the total cost by more than 40% compared to the zero-deteriorating rate, while the deteriorating raw material has less impact on the total cost (commonly less than 5% in our numerical examples). This indicates that more attention should be paid to the product than the raw material. Further, an increase in the number of retailers can make the replenishment frequency of the raw material increase significantly but the common replenishment cycle of the product decreases a little. This indicates that adding a new retailer would not be felt strongly by the other retailers but would be felt by the supplier of the raw material. © 2011 Elsevier B.V. All rights reserved.

Liu H.,Hong Kong University of Science and Technology | Ke W.,Clarkson University | Wei K.K.,City University of Hong Kong | Gu J.,Anhui University of Science and Technology | Chen H.,Anhui University of Science and Technology
Journal of Operations Management | Year: 2010

Drawing upon organizational culture and institutional theory, this study investigates how institutional pressures motivate the firm to adopt Internet-enabled Supply Chain Management systems (eSCM) and how such effects are moderated by organizational culture. The results of a survey of 131 firms suggest that the dimensions of institutional pressures (i.e., normative, mimetic, and coercive pressures) have differential effects on eSCM adoption intention. While mimetic pressures are not related to eSCM adoption intention, normative and coercive pressures are positively associated with eSCM adoption intention. In addition, organizational culture (i.e., flexibility orientation and control orientation) plays different roles in the relationships between these three dimensions of institutional pressures and eSCM adoption intention. While flexibility orientation negatively moderates the effects of coercive pressures and positively moderates the effects of mimetic pressures, control orientation positively moderates the effects of coercive and normative pressures and negatively moderates the effects of mimetic pressures. Implications and suggestions for future research are provided. © 2009 Elsevier B.V. All rights reserved.

Ni Y.,Anhui University of Science and Technology | Soh A.K.,Monash University
Acta Materialia | Year: 2014

The growth mechanisms of nonlinear buckle-delamination patterns from straight-sided to telephone cord and network-like blisters have been studied using a continuum modeling and simulation approach, which was extended to deal with cubic anisotropic elasticity in thin films. The buckling-delamination process is formulated using the time-dependent Ginzburg-Landau kinetic equations, driven by minimizing the film-substrate total free energy, including the elastic energies in both the film and the substrate, and the mixed-mode interfacial adhesion between them. It has been found that strong mixed-mode adhesion favored growth of telephone cord buckles via pinning of the buckle front, a sufficiently large biaxial compression caused branching of primary telephone cord buckles and an increase in the substrate compliance suppressed the undulation instability of the straight-sided blister tip. In addition, the compression anisotropy was found to dominate the oriented growth of the undulated blister. The good agreement between the details of simulated network-like blisters and those widely observed in experiments demonstrated that their formation was closely related to the above-mentioned mechanisms. © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Jiang P.,Anhui University of Science and Technology | Jiang P.,University of Pennsylvania | Du W.,Anhui University of Science and Technology | Du W.,University of Pennsylvania | And 5 more authors.
Nature Cell Biology | Year: 2011

Cancer cells consume large quantities of glucose and primarily use glycolysis for ATP production, even in the presence of adequate oxygen. This metabolic signature (aerobic glycolysis or the Warburg effect) enables cancer cells to direct glucose to biosynthesis, supporting their rapid growth and proliferation. However, both causes of the Warburg effect and its connection to biosynthesis are not well understood. Here we show that the tumour suppressor p53, the most frequently mutated gene in human tumours, inhibits the pentose phosphate pathway (PPP). Through the PPP, p53 suppresses glucose consumption, NADPH production and biosynthesis. The p53 protein binds to glucose-6-phosphate dehydrogenase (G6PD), the first and rate-limiting enzyme of the PPP, and prevents the formation of the active dimer. Tumour-associated p53 mutants lack the G6PD-inhibitory activity. Therefore, enhanced PPP glucose flux due to p53 inactivation may increase glucose consumption and direct glucose towards biosynthesis in tumour cells. © 2011 Macmillan Publishers Limited. All rights reserved.

Xu X.-W.,Beijing Computational Science Research Center | Li Y.,Beijing Computational Science Research Center | Li Y.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015

We demonstrate the possibility of optical nonreciprocal response in a three-mode optomechanical system where one mechanical mode is optomechanically coupled to two linearly coupled optical modes simultaneously. The optical nonreciprocal behavior is induced by the phase difference between the two optomechanical coupling rates, which breaks the time-reversal symmetry of the three-mode optomechanical system. Moreover, the three-mode optomechanical system can also be used as a three-port circulator for two optical modes and one mechanical mode, which we refer to as an optomechanical circulator. © 2015 American Physical Society.

Pan H.,Beihang University | Li Z.,Beihang University | Liu C.-C.,Beijing Institute of Technology | Zhu G.,Heze University | And 3 more authors.
Physical Review Letters | Year: 2014

We find theoretically a new quantum state of matter - the valley-polarized quantum anomalous Hall state in silicene. In the presence of Rashba spin-orbit coupling and an exchange field, silicene hosts a quantum anomalous Hall state with Chern number C=2. We show that through tuning the Rashba spin-orbit coupling, a topological phase transition results in a valley-polarized quantum anomalous Hall state, i.e., a quantum state that exhibits the electronic properties of both the quantum valley Hall state (valley Chern number Cv=3) and quantum anomalous Hall state with C=-1. This finding provides a platform for designing dissipationless valleytronics in a more robust manner. © 2014 American Physical Society.

Xu X.-W.,Beijing Computational Science Research Center | Li Y.,Beijing Computational Science Research Center | Li Y.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We study the photon-photon correlation properties of two-photon transport in a one-dimensional waveguide coupled to a nonlinear cavity via a real-space approach. It is shown that the intrinsic dissipation of the nonlinear cavity has an important effect upon the correlation of the transported photons. More importantly, strongly correlated photons can be obtained in the transmitted photons even when the nonlinear interaction strength is weak in the cavity. The strong photon-photon correlation is induced by the Fano resonance involving destructive interference between the plane wave and bound state for two-photon transport. © 2014 American Physical Society.

Xu X.-W.,Beijing Computational Science Research Center | Li Y.,Beijing Computational Science Research Center | Li Y.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

In recent studies [Liew, Phys. Rev. Lett. 104, 183601 (2010)PRLTAO0031-900710.1103/PhysRevLett.104.183601; Bamba, Phys. Rev. A 83, 021802(R) (2011)PLRAAN1050-294710.1103/PhysRevA.83.021802], due to destructive interference between different paths for two-photon excitation, strong photon antibunching can be obtained in a photonic molecule consisting of two coupled cavity modes with weak Kerr nonlinearity when one of the cavity modes is driven resonantly. Here, we study the photon statistics in a nonlinear photonic molecule with both the two cavity modes being driven coherently. We show that the statistical properties of the photons can be controlled by regulating the strength ratio and the relative phase between the two driving fields. The photonic molecules with two driven modes can be used to generate tunable single-photon sources or controlled photonic quantum gates with weak Kerr nonlinearity. © 2014 American Physical Society.

Xu X.-W.,Beijing Computational Science Research Center | Li Y.,Beijing Computational Science Research Center | Li Y.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2014

We study the photon statistics of symmetric and antisymmetric modes in a photonic molecule consisting of two linearly coupled nonlinear cavity modes. Our calculations show that strong photon antibunching of both symmetric and antisymmetric modes can be obtained even when the nonlinearity in the photonic molecule is weak. The strong antibunching effect results from the destructive interference between different paths for two-photon excitation. Moreover, we find that the optimal frequency detunings for strong photon antibunching in the symmetric and antisymmetric modes are linearly dependent on the coupling strength between the cavity modes in the photonic molecule. This implies that the photonic molecules can be used to generate tunable single-photon sources by tuning the values of the coupling strength between the cavity modes with weak nonlinearity. © 2014 American Physical Society.

Zhao P.,University of Jinan | Feng W.,Shandong Agricultural University | Kang Y.,Anhui University of Science and Technology
Automatica | Year: 2012

In this paper, global asymptotic stability in probability (GASiP) and stochastic input-to-state stability (SISS) for nonswitched stochastic nonlinear (nSSNL) systems and switched stochastic nonlinear (SSNL) systems are investigated. For the study of GASiP, the definition which we considered is not the usual notion of asymptotic stability in probability (stability in probability plus attractivity in probability); it can depict the properties of the system quantitatively. Correspondingly, based on this definition, some sufficient conditions are provided for nSSNL systems and SSNL systems. Furthermore, the definition of SISS is introduced and corresponding criteria are provided for nSSNL systems and SSNL systems. In the proof of the above results, to overcome the difficulties coming with the appearance of switching and the stochastic property at the same time, we generalize the past comparison principle and fully use the properties of the functions which we constructed. In terms of the average dwell-time of the switching laws, a sufficient SISS condition is obtained for SSNL systems. Finally, some examples are provided to demonstrate the applicability of our results. © 2012 Elsevier Ltd. All rights reserved.

Zheng Z.,Anhui University of Science and Technology | Wang C.,Anhui University of Science and Technology | Yu J.,Anhui University of Science and Technology | Reid S.R.,University of Aberdeen | Harrigan J.J.,University of Aberdeen
Journal of the Mechanics and Physics of Solids | Year: 2014

Dynamic uniaxial impact behaviour of metal foams using a 3D cell-based finite element model is examined. At sufficiently high loading rates, these materials respond by forming 'shock or consolidation waves' (Tan et al., 2005a, 2005b). However, the existing dynamic experimental methods have limitations in fully informing this behaviour, particularly for solving boundary/initial value problems. Recently, the problem of the shock-like response of an open-cell foam has been examined by Barnes et al. (2014) using the Hugoniot-curve representations. The present study is somewhat complementary to that approach and additionally aims to provide insight into the 'rate sensitivity' mechanism applicable to cellular materials. To assist our understanding of the 'loading rate sensitivity' behaviour of cellular materials, a virtual 'test' method based on the direct impact technique is explored. Following a continuum representation of the response, the strain field calculation method is employed to determine the local strains ahead of and behind the resulting 'shock front'. The dynamic stress-strain states in the densification stage are found to be different from the quasi-static ones. It is evident that the constitutive behaviour of the cellular material is deformation-mode dependent. The nature of the 'rate sensitivity' revealed for cellular materials in this paper is different from the strain-rate sensitivity of dense metals. It is shown that the dynamic stress-strain states behind a shock front of the cellular material lie on a unique curve and each point on the curve corresponds to a particular 'impact velocity', referred as the velocity upstream of the shock in this study. The dynamic stress-strain curve is related to a layer-wise collapse mode, whilst the equivalent quasi-static curve is related to a random shear band collapse mode. The findings herein are aimed at improving the experimental test techniques used to characterise the rate-sensitivity behaviour of real cellular materials and providing data appropriate to solving dynamic loading problems in which cellular metals are utilised. © 2014 Elsevier Ltd.

Culcer D.,Anhui University of Science and Technology | Culcer D.,CAS Institute of Theoretical Physics
Physica E: Low-Dimensional Systems and Nanostructures | Year: 2012

This paper reviews recent theoretical and experimental work on transport due to the surface states of three-dimensional topological insulators. The theoretical focus is on longitudinal transport in the presence of an electric field, including Boltzmann transport, quantum corrections and weak localization, as well as longitudinal and Hall transport in the presence of both electric and magnetic fields and/or magnetizations. Special attention is paid to transport at finite doping, and to the π-Berry phase, which leads to the absence of backscattering, Klein tunneling and half-quantized Hall response. Signatures of surface states in ordinary transport and magnetotransport are identified. The review also covers transport experiments of the past years, tracing its evolution from the initial obscuring of surface transport by bulk transport to the increasing success of experimental work in identifying transport due to the surface states. Current and likely future experimental challenges are given prominence and the present status of the field is assessed. © 2011 Elsevier B.V.

Zhang B.,Sun Yat Sen University | Hua Z.,Anhui University of Science and Technology
Computers and Industrial Engineering | Year: 2010

This paper investigates a portfolio approach to multi-product newsboy problem with budget constraint, in which the procurement strategy for each newsboy product is designed as portfolio contract. A portfolio contract consists of a fixed-price contract and an option contract. We model the problem as a profit-maximization model, and propose an efficient solution procedure after investigating the structural properties of the model. We conduct numerical studies to show the efficiency of the proposed solution procedure, and to compare three models with different procurement contracts, i.e., fixed-price contract, option contract, and portfolio contract. Numerical results are shown to demonstrate the advantage of the portfolio model, and sensitivity analysis is provided for obtaining some managerial insights. © 2010 Elsevier Ltd. All rights reserved.

Chen W.,University of Tennessee at Knoxville | Chen W.,Anhui University of Science and Technology | Chen W.,Harvard University | Santos E.J.G.,Harvard University | And 5 more authors.
Nano Letters | Year: 2013

Using first-principles calculations within density functional theory, we investigate the electronic and chemical properties of a single-layer MoS 2 adsorbed on Ir(111), Pd(111), or Ru(0001), three representative transition metal substrates having varying work functions but each with minimal lattice mismatch with the MoS2 overlayer. We find that, for each of the metal substrates, the contact nature is of Schottky-barrier type, and the dependence of the barrier height on the work function exhibits a partial Fermi-level pinning picture. Using hydrogen adsorption as a testing example, we further demonstrate that the introduction of a metal substrate can substantially alter the chemical reactivity of the adsorbed MoS2 layer. The enhanced binding of hydrogen, by as much as ∼0.4 eV, is attributed in part to a stronger H-S coupling enabled by the transferred charge from the substrate to the MoS2 overlayer, and in part to a stronger MoS 2-metal interface by the hydrogen adsorption. These findings may prove to be instrumental in future design of MoS2-based electronics, as well as in exploring novel catalysts for hydrogen production and related chemical processes. © 2013 American Chemical Society.

Fu Z.,Shanxi University | Huang L.,Shanxi University | Meng Z.,Shanxi University | Wang P.,Shanxi University | And 5 more authors.
Nature Physics | Year: 2014

The search for topological superconductors is a challenging task. One of the most promising directions is to use spin-orbit coupling through which an s-wave superconductor can induce unconventional p-wave pairing in a spin-polarized metal. Recently, synthetic spin-orbit couplings have been realized in cold-atom systems where instead of a proximity effect, s-wave pairing originates from a resonant coupling between s-wave molecules and itinerant atoms. Here we demonstrate a dynamic process in which spin-orbit coupling coherently produces s-wave Feshbach molecules from a fully polarized Fermi gas, and induces a coherent oscillation between these two. This demonstrates experimentally that spin-orbit coupling does coherently couple singlet and triplet states, and implies that the bound pairs of this system have a triplet p-wave component, which can become a topological superfluid by further cooling to condensation and confinement to one dimension. © 2014 Macmillan Publishers Limited.

Liu N.,University of Tennessee at Knoxville | Liu N.,Anhui University of Science and Technology | Khomami B.,University of Tennessee at Knoxville
Physical Review Letters | Year: 2013

We report for the first time the polymer-induced breakdown of large-scale Taylor vortex structures leading to drag enhancement in viscoelastic turbulent Taylor-Couette flows. Specifically, we demonstrate that upon the addition of trace amounts of soluble high molecular weight macromolecules the Newtonian large-scale Taylor vortices are replaced by small-scale vortices in the inner and outer cylinder wall regions. This flow transition and a commensurate drag increase of up to 62% are facilitated by the presence of large polymeric normal stresses in a narrow region immediately close to the outer wall. A simple mechanism for this striking flow transition is proposed with the aim of paving the way for a mechanistic understanding of polymer-induced structure and drag modifications in high-Re turbulent curvilinear flows. © 2013 American Physical Society.

Wu S.,University of Washington | Ross J.S.,University of Washington | Liu G.-B.,University of Hong Kong | Aivazian G.,University of Washington | And 10 more authors.
Nature Physics | Year: 2013

Crystal symmetry governs the nature of electronic Bloch states. For example, in the presence of time-reversal symmetry, the orbital magnetic moment and Berry curvature of the Bloch states must vanish unless inversion symmetry is broken. In certain two-dimensional electron systems such as bilayer graphene, the intrinsic inversion symmetry can be broken simply by applying a perpendicular electric field. In principle, this offers the possibility of switching on/off and continuously tuning the magnetic moment and Berry curvature near the Dirac valleys by reversible electrical control. Here we investigate this possibility using polarization-resolved photoluminescence of bilayer MoS2, which has the same symmetry as bilayer graphene but has a bandgap in the visible spectrum allowing direct optical probing. We find that in bilayer MoS2 the circularly polarized photoluminescence can be continuously tuned from-15% to 15% as a function of gate voltage, whereas in structurally non-centrosymmetric monolayer MoS2 the photoluminescence polarization is gate independent. The observations are well explained as resulting from the continuous variation of orbital magnetic moments between positive and negative values through symmetry control. © 2013 Macmillan Publishers Limited. All rights reserved.

Wu Z.,University of Minnesota | Wu Z.,Anhui University of Science and Technology | Justo J.F.,University of Minnesota | Justo J.F.,University of Sao Paulo | Wentzcovitch R.M.,University of Minnesota
Physical Review Letters | Year: 2013

The discovery of a pressure induced iron-related spin crossover in Mg (1-x)FexO ferropericlase (Fp) and Mg-silicate perovskite, the major phases of Earth's lower mantle, has raised new questions about mantle properties which are of central importance to seismology. Despite extensive experimental work on the anomalous elasticity of Fp throughout the crossover, inconsistencies reported in the literature are still unexplained. Here we introduce a formulation for thermoelasticity of spin crossover systems, apply it to Fp by combining it with predictive first principles density-functional theory with on-site repulsion parameter U calculations, and contrast results with available data on samples with various iron concentrations. We explain why the shear modulus of Fp should not soften along the crossover, as observed in some experiments, predict its velocities at lower mantle conditions, and show the importance of constraining the elastic properties of minerals without extrapolations for analyses of the thermochemical state of this region. © 2013 American Physical Society.

Wolf R.A.,Rice University | Chen C.X.,Anhui University of Science and Technology | Toffoletto F.R.,Rice University
Journal of Geophysical Research: Space Physics | Year: 2012

This paper presents a quantitative theory of "interchange oscillations," which occur as an earthward-moving low-entropy plasma bubble slows and eventually comes to rest. Our theoretical picture is based on an idealized situation where an ideal-MHD magnetic filament moves without friction through a stationary background that represents the plasma sheet. If the relevant region of the background plasma sheet is interchange stable, then the filament usually executes a damped oscillation about an equilibrium position, where its entropy parameter matches the local background. The oscillations are typically dramatic only if the equatorial plasma beta is greater than about one. We derive an approximate analytic formula for the oscillation period, which is not simply related to slow- or intermediate-wave travel times. For an oscillation that Panov and collaborators carefully studied using THEMIS data, our simple theory, though based on an unrealistic 2D background magnetic field, predicted an oscillation period that agrees with the observations within about 40%. The simulations suggest that the ionospheric oscillation should lag behind the magnetospheric one by between 40 and 90 degrees. Ionospheric conductance affects the damping rate, which maximizes for an auroral zone conductance ∼2 S. Adding a friction force acting between the filament and the background increases the decay rate of the oscillation. Copyright 2012 by the American Geophysical Union.

Wolf R.A.,Rice University | Chen C.X.,Anhui University of Science and Technology | Toffoletto F.R.,Rice University
Journal of Geophysical Research: Space Physics | Year: 2012

The main goal of this paper is to estimate the errors involved in applying a quasi-static convection model such as the Rice Convection Model (RCM) or its equilibrium version (RCM-E), which neglect inertial currents, to treat the injection of fresh particles into the inner magnetosphere in a substorm expansion phase. The approach is based on the idea that the dipolarization process involves earthward motion of a bubble that consists of flux tubes that have lower values of the entropy parameter than the surrounding medium. Our tests center on comparing MHD simulations with RCM- and RCM-E-like quasi-static approximations, for cases where the bubble is considered to be a thin ideal-MHD filament. Those quasi-static solutions miss the interchange oscillations that are often a feature of the MHD results. RCM and, to a lesser extent, RCM-E calculations tend to overestimate the westward electric field at the ionospheric footprint of the bubble and underestimate its duration. However, both get the time integral of the E × B drift velocity right as well as the net energization of the particles in the filament. The quasi-static approximation is most accurate if its computed value of the braking time of the bubble's earthward motion is long compared to the period of the relevant interchange oscillation. Comparison of MHD filament simulations of interchange instability with corresponding RCM calculations suggests a similar validity criterion. For plasma sheet conditions, the quasi-static approximation is typically best if the background medium has low , worst if it consists of highly stretched field lines. Copyright 2012 by the American Geophysical Union.

Wang R.,Anhui University of Science and Technology | Wang R.,Chinese Academy of Sciences | Lu Q.,Anhui University of Science and Technology | Lu Q.,Chinese Academy of Sciences | And 2 more authors.
Physical Review Letters | Year: 2010

Numerical simulations have predicted that an extended current sheet may be unstable to secondary magnetic islands in the vicinity of the X line, and these islands can dramatically influence the reconnection rate. In this Letter, we present the first evidence of such a secondary island near the center of an ion diffusion region, which is consistent with the action of the secondary island instability occurring in the vicinity of the X line. The island is squashed in the z direction with a strong core magnetic field. Energetic electrons with anisotropic or field-aligned bidirectional fluxes are found in the ion diffusion region, and the enhancement of energetic electron fluxes is more obvious inside the secondary island. © 2010 The American Physical Society.

Chen H.,University of Tennessee at Knoxville | Chen H.,Oak Ridge National Laboratory | Zhu W.,University of Tennessee at Knoxville | Zhu W.,Oak Ridge National Laboratory | And 3 more authors.
Physical Review Letters | Year: 2010

Using first-principles calculations within density functional theory, we study the energetics and kinetics of C nucleation in the early stages of epitaxial graphene growth on three representative stepped metal surfaces: Ir(111), Ru(0001), and Cu(111). We find that on the flat surfaces of Ir(111) and Ru(0001), two C atoms repel each other, while they prefer to form a dimer on Cu(111). Moreover, the step edges on Ir and Ru surfaces cannot serve as effective trapping centers for single C adatoms, but can readily facilitate the formation of C dimers. These contrasting behaviors are attributed to the delicate competition between C-C bonding and C-metal bonding, and a simple generic principle is proposed to predict the nucleation sites of C adatoms on many other metal substrates with the C-metal bond strengths as the minimal inputs. © 2010 The American Physical Society.

Wei R.,Anhui University of Science and Technology | Wei R.,Cornell University | Mueller E.J.,Cornell University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We calculate the magnetic-field dependence of Rabi rates for two-photon optical Raman processes in alkali-metal atoms. Due to a decoupling of the nuclear and electronic spins, these rates fall with increasing field. At the typical magnetic fields of alkali-metal-atom Feshbach resonances (B∼200-1200 G), the Raman rates have the same order of magnitude as their zero-field values, suggesting one can combine Raman-induced gauge fields or spin-orbital coupling with strong Feshbach-induced interactions. The exception is 6Li, where there is a factor-of-7 suppression in the Raman coupling, compared to its already small zero-field value. © 2013 American Physical Society.

Wei R.,Anhui University of Science and Technology | Wei R.,Cornell University | Mueller E.J.,Cornell University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We theoretically study trapped one-dimensional Fermi gases in the presence of spin-orbit coupling induced by Raman lasers. The gas changes from a conventional (nontopological) superfluid to a topological superfluid as one increases the intensity of the Raman lasers above a critical chemical-potential-dependent value. Solving the Bogoliubov-de Gennes equations self-consistently, we calculate the density of states in real and momentum space at finite temperatures. We study Majorana fermions (MFs) which appear at the boundaries between topologically trivial and topologically nontrivial regions. We linearize the trap near the location of a MF, finding an analytic expression for the localized MF wave function and the gap between the MF state and other edge states. © 2012 American Physical Society.

Cai Z.,University of California at San Diego | Zhou X.,Anhui University of Science and Technology | Wu C.,University of California at San Diego | Wu C.,Tsinghua University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We investigate magnetic properties in the superfluid and Mott-insulating states of two-component bosons with spin-orbit (SO) coupling in two-dimensional square optical lattices. The spin-independent hopping integral t and SO coupled one λ are fitted from band-structure calculations in the continuum, which exhibit oscillations with increasing SO coupling strength. The magnetic superexchange model is derived in the Mott-insulating state with one particle per site, characterized by the Dzyaloshinsky-Moriya interaction. In the limit of |λ||t|, we find a spin spiral Mott state whose pitch value is the same as that in the incommensurate superfluid state, while in the opposite limit |t| |λ|, the ground state exhibits a 2×2 in-plane spin pattern. © 2012 American Physical Society.

Wang Y.,Xiamen University | Lin H.-X.,Xiamen University | Chen L.,Xiamen University | Ding S.-Y.,Xiamen University | And 7 more authors.
Chemical Society Reviews | Year: 2014

One important objective of molecular assembly research is to create highly complex functional chemical systems capable of responding, adapting, and evolving. Compared with living systems, the synthetic systems are still rather primitive and are far from realizing those features. Nature is by far the most important source of inspiration for designing and creating such systems. In this critical review, we summarize an alternative approach, inspired by catalysis, to examine and describe some molecular assembly processes. A new term, "catassembly," is suggested to refer to the increase in the rate and control of a molecular assembly process. This term combines the words "catalysis" and "assembly," and identifiably retains the Greek root "cat-" of catalysis. The corresponding verb is "catassemble" and the noun is "catassembler", referring to the "helper" species. Catassembly in molecular assembly is a concept that is analogous to catalysis in chemical synthesis. After using several examples to illustrate the characteristics of catassembly, we discuss future methodological and theoretical developments. We also emphasize the significance of the synergy between chemical synthesis and molecular assembly, especially for hierarchical assembly systems. Because most efforts in the field of molecular assembly have been devoted to the design and synthesis of molecular building blocks, we wish to stress the apparently missing yet critical link to complex chemical systems, i.e., the design and utilization of molecular catassemblers to facilitate the formation of functional molecular assemblies from building blocks with high efficiency and selectivity. This rational control and accelerated method will promote the systems chemistry approach, and may expand the spectrum of molecular assembly from basic science to applications. © 2014 The Royal Society of Chemistry.

Guo B.-Z.,Anhui University of Science and Technology | Guo B.-Z.,CAS Academy of Mathematics and Systems Science | Guo B.-Z.,University of Witwatersrand | Guo B.-Z.,Shanxi University | Zhao Z.-L.,Anhui University of Science and Technology
Systems and Control Letters | Year: 2011

The extended state observer first proposed by Jingqing Han in [J.Q. Han, A class of extended state observers for uncertain systems, Control Decis. 10 (1) (1995) 8588 (in Chinese)] is the key link toward the active disturbance rejection control that is taking off as a technology after numerous successful applications in engineering. Unfortunately, there is no rigorous proof of convergence to date. In this paper, we attempt to tackle this long unsolved extraordinary problem. The main idea is to transform the error equation of objective system with its extended state observer into a asymptotical stable system with a small disturbance, for which the effect of total disturbance error is eliminated by the high-gain. © 2011 Elsevier B.V. All rights reserved.

Yuan K.,Anhui University of Science and Technology | Ling Q.,Anhui University of Science and Technology | Yin W.,University of California at Los Angeles
SIAM Journal on Optimization | Year: 2016

Consider the consensus problem of minimizing (equation presented), where x ∈ ℝp and each fi is only known to the individual agent i in a connected network of n agents. To solve this problem and obtain the solution, all the agents collaborate with their neighbors through information exchange. This type of decentralized computation does not need a fusion center, offers better network load balance, and improves data privacy. This paper studies the decentralized gradient descent method [A. Nedic and A. Ozdaglar, IEEE Trans. Automat. Control, 54 (2009), pp. 48-61], in which each agent i updates its local variable x(i) ∈ ℝn by combining the average of its neighbors' with a local negative-gradient step (equation presented). The method is described by the iteration (equation presented), for each agent i, where wij is nonzero only if i and j are neighbors or i = j and the matrix W = [wij] ∈ ℝn×n is symmetric and doubly stochastic. This paper analyzes the convergence of this iteration and derives its rate of convergence under the assumption that each fi is proper closed convex and lower bounded, ∇fi is Lipschitz continuous with constant Lfi > 0, and the stepsize α is fixed. Provided that (equation presented), where Lh = maxi{Lfi} and (equation presented), the objective errors of all the local solutions and the networkwide mean solution reduce at rates of O(1/k) until they reach a level of O (α). If fi are strongly convex with modulus μfi and α ≤ min(equation presented), where (equation presented), then all the local solutions and the mean solution converge to the global minimizer x∗ at a linear rate until reaching an O(α)-neighborhood of x∗. We also develop an iteration for decentralized basis pursuit and establish its linear convergence to an O(α)-neighborhood of the true sparse signal. This analysis reveals how the convergence of (equation presented), for each agent i, depends on the stepsize, function convexity, and network spectrum. © 2016 Society for Industrial and Applied Mathematics.

Yang X.-Z.,Anhui University of Science and Technology | Du X.-J.,Anhui University of Science and Technology | Liu Y.,Anhui University of Science and Technology | Zhu Y.-H.,Anhui University of Science and Technology | And 3 more authors.

Rationally designed PIC nanoparticles as next-generation delivery system: we have developed a core-shell-corona PIC nanoparticle âŠNP/Pt@PPC-DA as a next-generation delivery system. âŠNP/Pt@PPC-DA exhibits prolonged circulation and enhanced drug accumulation in tumors. Subsequently, tumor pH leads to the release of âŠNP/Pt, which facilitates cellular uptake followed by rapid intracellular cisplatin release. Using this delivery strategy cisplatin-resistant tumor growth in a murine xenograft model has been successfully suppressed. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yang F.,Anhui University of Science and Technology | Liu Y.,SLAC | Martha S.K.,Oak Ridge National Laboratory | Wu Z.,Anhui University of Science and Technology | And 5 more authors.
Nano Letters | Year: 2014

Understanding the evolution of chemical composition and morphology of battery materials during electrochemical cycling is fundamental to extending battery cycle life and ensuring safety. This is particularly true for the much debated high energy density (high voltage) lithium-manganese rich cathode material of composition Li1 + xM1 - xO2 (M = Mn, Co, Ni). In this study we combine full-field transmission X-ray microscopy (TXM) with X-ray absorption near edge structure (XANES) to spatially resolve changes in chemical phase, oxidation state, and morphology within a high voltage cathode having nominal composition Li1.2Mn0.525Ni 0.175Co0.1O2. Nanoscale microscopy with chemical/elemental sensitivity provides direct quantitative visualization of the cathode, and insights into failure. Single-pixel (∼30 nm) TXM XANES revealed changes in Mn chemistry with cycling, possibly to a spinel conformation and likely including some Mn(II), starting at the particle surface and proceeding inward. Morphological analysis of the particles revealed, with high resolution and statistical sampling, that the majority of particles adopted nonspherical shapes after 200 cycles. Multiple-energy tomography showed a more homogeneous association of transition metals in the pristine particle, which segregate significantly with cycling. Depletion of transition metals at the cathode surface occurs after just one cycle, likely driven by electrochemical reactions at the surface. © 2014 American Chemical Society.

Zhou H.-X.,Florida State University | Pang X.,Florida State University | Lu C.,Anhui University of Science and Technology
Physical Chemistry Chemical Physics | Year: 2012

The binding of intrinsically disordered proteins (IDPs) to structured targets is gaining increasing attention. Here we review experimental and computational studies on the binding kinetics of IDPs. Experiments have yielded both the binding rate constants and the binding mechanisms, the latter via mutation and deletion studies and NMR techniques. Most computational studies have aimed at qualitative understanding of the binding rate constants or at mapping the free energy surfaces after the IDPs are engaged with their targets. The experiments and computation show that IDPs generally gain structures after they are engaged with their targets; that is, interactions with the targets facilitate the IDPs' folding. It also seems clear that the initial contact of an IDP with the target is formed by just a segment, not the entire IDP. The docking of one segment to its sub-site followed by coalescing of other segments around the corresponding sub-sites emerges as a recurring feature in the binding of IDPs. Such a dock-and-coalesce model forms the basis for quantitative calculation of binding rate constants. For both disordered and ordered proteins, strong electrostatic attraction with their targets can enhance the binding rate constants by several orders of magnitude. There are now tremendous opportunities in narrowing the gap in our understanding of IDPs relative to ordered proteins with regard to binding kinetics. © 2012 the Owner Societies.

Yang X.-Z.,Anhui University of Science and Technology | Dou S.,Anhui University of Science and Technology | Wang Y.-C.,Anhui University of Science and Technology | Long H.-Y.,Anhui University of Science and Technology | And 4 more authors.
ACS Nano | Year: 2012

The clinical success of therapeutics of small interfering RNA (siRNA) is still hindered by its delivery systems. Cationic polymer or lipid-based vehicles as the major delivery systems of siRNA cannot sufficiently satisfy siRNA therapeutic applications. It is hypothesized that cationic lipid-polymer hybrid nanoparticles may take advantage of both polymeric and lipid-based nanoparticles for siRNA delivery, while diminishing the shortcomings of both. In this study, cationic lipid-polymer hybrid nanoparticles were prepared by a single-step nanoprecipitation of a cationic lipid (N,N-bis(2-hydroxyethyl)-N-methyl-N-(2- cholesteryloxycarbonyl aminoethyl) ammonium bromide, BHEM-Chol) and amphiphilic polymers for systemic delivery of siRNA. The formed hybrid nanoparticles comprised a hydrophobic polylactide core, a hydrophilic poly(ethylene glycol) shell, and a cationic lipid monolayer at the interface of the core and the shell. Such hybrid nanoparticles exhibited excellent stability in serum and showed significantly improved biocompatibility compared to that of pure BHEM-Chol particles. The hybrid nanoparticles were capable of delivering siRNA into BT474 cells and facilitated the escape of loaded siRNA from the endosome into the cytoplasm. The hybrid nanoparticles carrying polo-like kinase 1 (Plk1)-specific siRNA (siPlk1) remarkably and specifically downregulated expression of the oncogene Plk1 and induced cancer cell apoptosis both in vitro and in vivo and significantly suppressed tumor growth following systemic administration. We demonstrate that this system is stable, nontoxic, highly efficient, and easy to scale up, bringing the clinical application of siRNA therapy one important step closer to reality. © 2012 American Chemical Society.

Cao M.-J.,Anhui University of Science and Technology | Wang Z.,Anhui University of Science and Technology | Wirtz M.,University of Heidelberg | Hell R.,University of Heidelberg | And 2 more authors.
Plant Journal | Year: 2013

Plants play a prominent role as sulfur reducers in the global sulfur cycle. Sulfate, the major form of inorganic sulfur utilized by plants, is absorbed and transported by specific sulfate transporters into plastids, especially chloroplasts, where it is reduced and assimilated into cysteine before entering other metabolic processes. How sulfate is transported into the chloroplast, however, remains unresolved; no plastid-localized sulfate transporters have been previously identified in higher plants. Here we report that SULTR3;1 is localized in the chloroplast, which was demonstrated by SULTR3;1-GFP localization, Western blot analysis, protein import as well as comparative analysis of sulfate uptake by chloroplasts between knockout mutants, complemented transgenic plants, and the wild type. Loss of SULTR3;1 significantly decreases the sulfate uptake of the chloroplast. Complementation of the sultr3;1 mutant phenotypes by expression of a 35S-SULTR3;1 construct further confirms that SULTR3;1 is one of the transporters responsible for sulfate transport into chloroplasts. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

Bian L.,Chongqing University | Bian L.,CAS Institute of Theoretical Physics | Chen N.,Anhui University of Science and Technology | Liu D.,CAS Institute of Theoretical Physics | And 2 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2016

We explain the recent diphoton excesses around 750 GeV by both ATLAS and CMS as a singlet scalar Φ which couples to SM gluon and neutral gauge bosons only through higher-dimensional operators. A natural explanation is that Φ is a pseudo-Nambu-Goldstone boson (pNGB) which receives parity violation through anomaly if there exists a hidden strong dynamics. The singlet and other light pNGBs will decay into two SM gauge bosons and even serves as the metastable colored states which can be probed in the future. By accurately measuring their relative decay and the total production rate in the future, we will learn the underlying strong dynamics parameter. The lightest baryon in this confining theory could serve as a viable dark matter candidate. © 2016 American Physical Society.

Zhang X.,Anhui University of Science and Technology | Zhang J.,Anhui University of Science and Technology | Zhao J.,Anhui University of Science and Technology | Pan B.,Anhui University of Science and Technology | And 3 more authors.
Journal of the American Chemical Society | Year: 2012

Controlling the synthesis of atomic-thick nanosheets of nonlayered materials is extremely challenging because of the lack of an intrinsic driving force for anisotropic growth of two-dimensional (2D) structures. In that case, control of the anisotropy such as oriented attachment of small building blocks during the reaction process will be an effective way to achieve 2D nanosheets. Those atomic-thick nanosheets possess novel electronic structures and physical properties compared with the corresponding bulk samples. Here we report Co 9Se 8 single-crystalline nanosheets with atomic thickness and unique lamellar stacking formed by 2D oriented attachment. The atomic-thick Co 9Se 8 nanosheets were found to exhibit intrinsic half-metallic ferromagnetism, as supported by both our experimental measurements and theoretical calculations. This work will not only open a new door in the search for new half-metallic ferromagnetic systems but also pave a practical way to design ultrathin, transparent, and flexible paperlike spintronic devices. © 2012 American Chemical Society.

Wei R.,Anhui University of Science and Technology | Wei R.,Cornell University | Mueller E.J.,Cornell University
Physical Review Letters | Year: 2012

We study the vortex structures of a (pseudo)spin-1/2 Fermi gas experiencing a uniform effective magnetic field in an anisotropic trap that interpolates between quasi-one dimensional (1D) and quasi-two dimensional (2D). At a fixed chemical potential, reducing the anisotropy (or equivalently increasing the attractive interactions or increasing the magnetic field) leads to instabilities towards pair density waves and vortex lattices. Reducing the chemical potential stabilizes the system. We calculate the phase diagram and explore the density and pair density. The structures are similar to those predicted for superfluid Bose gases. We further calculate the paired fraction, showing how it depends on the chemical potential and anisotropy. © 2012 American Physical Society.

Wang S.,Anhui University of Science and Technology | Wang S.,CAS Institute of Theoretical Physics
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2010

Since the energy momentum tensor of a magnetic field always contains a spin-2 component in its anisotropic stress, stochastic primordial magnetic field (PMF) in the early universe must generate stochastic gravitational-wave (GW) background. This process will greatly affect the relic gravitational wave (RGW), which is one of the major scientific goals of the laser interferometer GW detections. Recently, the fifth science (S5) run of laser interferometer gravitational-wave observatory (LIGO) gave a latest upper limit ΩGW<6.9×10-6 on the RGW background. Utilizing this upper limit, we derive new PMF limits: for a scale of galactic cluster λ=1Mpc, the amplitude of PMF, that produced by the electroweak phase transition, has to be weaker than Bλ≤4×10-7 G; for a scale of supercluster λ=100Mpc, the amplitude of PMF has to be weaker than Bλ≤9×10-11 G. In this manner, GW observation has potential to make interesting contributions to the study of primordial magnetic field. © 2010 The American Physical Society.

Qin S.,Florida State University | Cai L.,Anhui University of Science and Technology | Zhou H.-X.,Florida State University
Physical Biology | Year: 2012

In cellular environments, two protein molecules on their way to form a specific complex encounter many bystander macromolecules. The latter molecules, or crowders, affect both the energetics of the interaction between the test molecules and the dynamics of their relative motion. In earlier work (Zhou and Szabo 1991 J. Chem. Phys. 95 5948-52), it has been shown that, in modeling the association kinetics of the test molecules, the presence of crowders can be accounted for by their energetic and dynamic effects. The recent development of the transient-complex theory for protein association in dilute solutions makes it possible to easily incorporate the energetic and dynamic effects of crowders. The transient complex refers to a late on-pathway intermediate, in which the two protein molecules have near-native relative separation and orientation, but have yet to form the many short-range specific interactions of the native complex. The transient-complex theory predicts the association rate constant as ka = ka0exp(- ΔG*el/k BT), where ka0 is the 'basal' rate constant for reaching the transient complex by unbiased diffusion, and the Boltzmann factors captures the influence of long-range electrostatic interactions between the protein molecules. Crowders slow down the diffusion, therefore reducing the basal rate constant (to kac0), and induce an effective interaction energy ΔGc. We show that the latter interaction energy for atomistic proteins in the presence of spherical crowders is 'long'-ranged, allowing the association rate constant under crowding to be computed as kac = kac0exp[ - (ΔG*el + ΔG* c)/kBT]. Applications demonstrate that this computational method allows for realistic modeling of protein association kinetics under crowding. © 2012 IOP Publishing Ltd.

Chen H.,University of Tennessee at Knoxville | Zhu W.,University of Tennessee at Knoxville | Zhu W.,Oak Ridge National Laboratory | Xiao D.,Oak Ridge National Laboratory | And 2 more authors.
Physical Review Letters | Year: 2011

Surface states-the electronic states emerging as a solid material terminates at a surface-are usually vulnerable to contaminations and defects. The robust topological surface state(s) (TSS) on the three-dimensional topological insulators provide a perfect platform for exploiting surface states in less stringent environments. Employing first-principles density functional theory calculations, we demonstrate that the TSS can play a vital role in facilitating surface reactions by serving as an effective electron bath. We use CO oxidation on gold-covered Bi2Se3 as a prototype example, and show that the robust TSS can significantly enhance the adsorption energy of both CO and O2 molecules, by promoting different directions of static electron transfer. The concept of TSS as an electron bath may lead to new design principles beyond the conventional d-band theory of heterogeneous catalysis. © 2011 American Physical Society.

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

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

Shi W.,Anhui University of Science and Technology | Ling Q.,Anhui University of Science and Technology | Yuan K.,Anhui University of Science and Technology | Wu G.,Anhui University of Science and Technology | Yin W.,University of California at Los Angeles
IEEE Transactions on Signal Processing | Year: 2014

In decentralized consensus optimization, a connected network of agents collaboratively minimize the sum of their local objective functions over a common decision variable, where their information exchange is restricted between the neighbors. To this end, one can first obtain a problem reformulation and then apply the alternating direction method of multipliers (ADMM). The method applies iterative computation at the individual agents and information exchange between the neighbors. This approach has been observed to converge quickly and deemed powerful. This paper establishes its linear convergence rate for the decentralized consensus optimization problem with strongly convex local objective functions. The theoretical convergence rate is explicitly given in terms of the network topology, the properties of local objective functions, and the algorithm parameter. This result is not only a performance guarantee but also a guideline toward accelerating the ADMM convergence. © 2014 IEEE.

Shi D.-M.,Bohai University | Wang B.-H.,Anhui University of Science and Technology
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

Game theory is introduced to simulate the complicated interaction relations among the conflicting pedestrians in a pedestrian flow system, which is defined on a square lattice with the parallel update rule. Modified on the traditional lattice gas model, each pedestrian can move to not only an empty site, but also an occupied site. It is found that each individual chooses its neighbor randomly and occupies the site with the probability W(x→y)=11+exp[-(P x-Ux)/κ], where Px is the x's payoff representing his personal energy, and Ux is the average payoff of its neighborhood indicating the potential well energy if he stays. Two types of pedestrians are considered, and they interact with their neighbors following the payoff matrix of snowdrift game theory. The cost-to-benefit ratio r=c/(2b-c) (where b is the perfect payoff and c is the labor cost) represents the fear index of the pedestrians in this model. It is found that there exists a moderate value of r leading to the shortest escape time, and the situation for large values of r is better than that for small ones in general. In addition, the pedestrian flow system always arrives at a consistent state in which the two types of walkers have the same number and evolve by the same law irrespectively of the parameters, which can be interpreted as the self-organization effect of pedestrian flow. It is also proven that the time point of the onset of the steady state is unrelated to the scale of the pedestrians and the square lattice. Meanwhile, the system exhibits different dynamics before reaching the consistent state: the number of the two types of walkers oscillates when P C>0.5 (i.e., probability to change the present strategy), while no oscillation happens for PC≤0.5. Finally, it is shown that a smaller density of pedestrians ρ induces a shorter average escape time. © 2013 American Physical Society.

Liu J.,Anhui University of Science and Technology | Li Y.,Anhui University of Science and Technology | Li Y.,Tsinghua University | Li J.,Tsinghua University | Deng Z.,Anhui University of Science and Technology
Journal of Materials Chemistry | Year: 2010

Non-covalent DNA decorations on the basal planes of graphene oxide and reduced graphene oxide nanosheets are realized. The resulting DNA-carbon bioconjugates (DNA-GO or DNA-RGO) bearing multiple thiol groups tagged on DNA strands are then employed to scaffold the two-dimensional self-assembly of gold nanoparticles (AuNPs) into metal-carbon hybrid nanostructures (namely AuNP-DNA-GO or AuNP-DNA-RGO) that may find important applications in various aspects. The resulting heteronanostructures incorporating metal nanoparticles obtained by self-assembly are highly stable and water-soluble, and can be easily isolated by gel electrophoresis to guarantee high purity. Thanks to the noncovalent features of this method, either GO or RGO do not suffer from any permanent alterations of their structures and properties. In addition, the nanoparticles still maintain their optical absorbance after being assembled, and the assembly process is highly specific. This self-assembly based method for constructing heterostructured materials is excellent at overcoming any incompatibilities between nanoparticle syntheses and the formation of hybrid structures. As a result, this strategy is easily adaptable to various other materials other than gold nanoparticles and also favors the combinatorial assembly of multiple nanophases on a single nanosheet. © 2010 The Royal Society of Chemistry.

Bao X.-H.,University of Heidelberg | Bao X.-H.,Anhui University of Science and Technology | Reingruber A.,University of Heidelberg | Dietrich P.,University of Heidelberg | And 8 more authors.
Nature Physics | Year: 2012

Quantum memories are regarded as one of the fundamental building blocks of linear-optical quantum computation and long-distance quantum communication. A long-standing goal to realize scalable quantum information processing is to build a long-lived and efficient quantum memory. There have been significant efforts distributed towards this goal. However, either efficient but short-lived or long-lived but inefficient quantum memories have been demonstrated so far. Here we report a high-performance quantum memory in which long lifetime and high retrieval efficiency meet for the first time. By placing a ring cavity around an atomic ensemble, employing a pair of clock states, creating a long-wavelength spin wave and arranging the set-up in the gravitational direction, we realize a quantum memory with an intrinsic spin wave to photon conversion efficiency of 73(2)% together with a storage lifetime of 3.2(1)ms. This realization provides an essential tool towards scalable linear-optical quantum information processing. © 2012 Macmillan Publishers Limited. All rights reserved.

Pan J.-W.,Anhui University of Science and Technology | Chen Z.-B.,Anhui University of Science and Technology | Lu C.-Y.,Anhui University of Science and Technology | Weinfurter H.,Ludwig Maximilians University of Munich | And 6 more authors.
Reviews of Modern Physics | Year: 2012

Multiphoton interference reveals strictly nonclassical phenomena. Its applications range from fundamental tests of quantum mechanics to photonic quantum information processing, where a significant fraction of key experiments achieved so far comes from multiphoton state manipulation. The progress, both theoretical and experimental, of this rapidly advancing research is reviewed. The emphasis is given to the creation of photonic entanglement of various forms, tests of the completeness of quantum mechanics (in particular, violations of local realism), quantum information protocols for quantum communication (e.g., quantum teleportation, entanglement purification, and quantum repeater), and quantum computation with linear optics. The scope of the review is limited to "few-photon" phenomena involving measurements of discrete observables. © 2012 American Physical Society.

Zheng Z.,Anhui University of Science and Technology | Liu Y.,Anhui University of Science and Technology | Yu J.,Anhui University of Science and Technology | Reid S.R.,University of Aberdeen
International Journal of Impact Engineering | Year: 2012

As shown in the extensive studies of the dynamic responses of cellular materials, when the impact velocity is high, 'shock' waves can be generated. Because of the nature of the cellular structure, behind the 'shock (or compaction) front', there is a region of thickness approximately one single-cell-layer, across which the deformation can vary enormously, with strains of the order of ∼0.8, say. This is due to the extensive and progressive crushing of the cells. The compressed part of the cellular material is crushed and densified as the material crosses the front. Depending on the details of the cellular geometry, this locally large deformation can be very intricate to model, however, a first order 'shock' model can be defined, which permits a useful understanding of the phenomenology of the dynamic deformation of cellular materials, particularly metal foams. However, when the impact velocity is not very high, there exists a different type of front behind which the strain, though plastic, does not reach the densification strain. Based on one-dimensional continuum-based stress wave theory with a 'rigid unloading' assumption, in this paper a theoretical framework is established to explore the corresponding inherent mechanisms as a simple extension of the original 'shock' theory. Two models, namely the Shock-Mode model and the Transitional-Mode model, are introduced. The distributions of stress, strain and velocity in the foam rod are derived. The theoretical results show that for a Shock Mode, behind the front the initial strain remains constant and the initial stress varies proportionally with the square of the impact velocity, but for a Transition Mode, the initial strain and stress behind the front reduce linearly with reducing impact velocity. The critical impact velocities for modes transition are predicted. Two dimensionless parameters, namely the shock-enhancement parameter and the stress-hardening parameter, are defined and the features of the theoretical predictions are presented. Compared to the experimental results, the responses at the ends of foam rod are well predicted by the present models and also by the R-P-P-L model. However, deformation mechanisms uncovered by the present modes and the R-P-P-L model are very different when the impact velocity is not very high. The present simple, wave-based models extend the understanding of metallic foams to loading over a wider range of impact velocities than the previous models. In particular, the sub-shock-like behaviour, which has not yet been dealt within the literature, can be better understood through the new Transitional-Mode model. © 2011 Elsevier Ltd. All rights reserved.

Pei H.,CAS Shanghai Institutes for Biological Sciences | Yao Y.,CAS Shanghai Institutes for Biological Sciences | Yang Y.,CAS Shanghai Institutes for Biological Sciences | Liao K.,CAS Shanghai Institutes for Biological Sciences | And 2 more authors.
Cell Death and Differentiation | Year: 2011

Krüppel-like factors (KLFs) as a family of zinc-finger transcription factors involve in the regulation of many physiological processes. In these studies, KLF9 was characterized for its role in adipogenesis. The expression of KLF9 was markedly upregulated during the middle stage of 3T3-L1 adipocyte differentiation, and inhibition of KLF9 by RNAi impaired adipogenesis. Using promoter deletion and mutation analysis, we identified two KLF9-binding sites within the 0.6-kb region of the PPARγ2 proximal promoter, indicating that KLF9 interacts with the PPARγ2 promoter. Furthermore, we found that KLF9 could synergistically activate PPARγ2 promoter by directly interacting with C/EBPα. In addition, overexpression of PPARγ2 rescued the impairment of adipocyte differentiation induced by KLF9 knockdown, which supports that PPARγ2 is a downstream target of KLF9. Collectively, our results indicate KLF9 as a key pro-adipogenic transcription factor through regulation of PPARγ2 expression with C/EBPα at the middle stage of adipogenesis. © 2011 Macmillan Publishers Limited All rights reserved.

Pires R.,University of Heidelberg | Ulmanis J.,University of Heidelberg | Hafner S.,University of Heidelberg | Repp M.,University of Heidelberg | And 4 more authors.
Physical Review Letters | Year: 2014

We observe two consecutive heteronuclear Efimov resonances in an ultracold Li-Cs mixture by measuring three-body loss coefficients as a function of magnetic field near a Feshbach resonance. The first resonance is detected at a scattering length of a-(0)=-320(10)a0, corresponding to ∼7(∼3) times the Li-Cs (Cs-Cs) van der Waals range. The second resonance appears at 5.8(1.0)a-(0), close to the unitarity-limited regime at the sample temperature of 450 nK. Indication of a third resonance is found in the atom loss spectra. The scaling of the resonance positions is close to the predicted universal scaling value of 4.9 for zero temperature. Deviations from universality might be caused by finite-range and temperature effects, as well as magnetic field-dependent Cs-Cs interactions. © 2014 American Physical Society.

Kohse-Hoinghaus K.,Bielefeld University | Osswald P.,Bielefeld University | Cool T.A.,Cornell University | Kasper T.,Sandia National Laboratories | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2010

Biofuels, such as bio-ethanol, bio-butanol, and biodiesel, are of increasing interest as alternatives to petroleum-based transportation fuels because they offer the long-term promise of fuel-source regenerability and reduced climatic impact. Current discussions emphasize the processes to make such alternative fuels and fuel additives, the compatibility of these substances with current fuel-delivery infrastructure and engine performance, and the competition between biofuel and food production. However, the combustion chemistry of the compounds that constitute typical biofuels, including alcohols, ethers, and esters, has not received similar public attention. Herein we highlight some characteristic aspects of the chemical pathways in the combustion of prototypical representatives of potential biofuels. The discussion focuses on the decomposition and oxidation mechanisms and the formation of undesired, harmful, or toxic emissions, with an emphasis on transportation fuels. New insights into the vastly diverse and complex chemical reaction networks of biofuel combustion are enabled by recent experimental investigations and complementary combustion modeling. Understanding key elements of this chemistry is an important step towards the intelligent selection of next-generation alternative fuels. © 2010 Wiley-VCH Verlag GmbH & Co. KCaA.

Wang H.,Anhui University of Science and Technology | Mo H.J.,University of Massachusetts Amherst | Yang X.,Key Laboratory for Research in Galaxies and Cosmology | van den Bosch F.C.,Yale University
Monthly Notices of the Royal Astronomical Society | Year: 2012

Cosmic velocity and tidal fields are important for the understanding of the cosmic web and the environments of galaxies, and can also be used to constrain cosmology. In this paper, we reconstruct these two fields in the Sloan Digital Sky Survey (SDSS) volume from dark matter haloes represented by galaxy groups. Detailed mock catalogues are used to test the reliability of our method against uncertainties arising from redshift distortions, survey boundaries and false identifications of groups by our group finder. We find that both the velocity and tidal fields, smoothed on a scale of ~2h -1Mpc, can be reliably reconstructed in the inner region (~66per cent) of the survey volume. The reconstructed tidal field is used to split the cosmic web into four categories: clusters, filaments, sheets and voids, depending on the sign of the eigenvalues of local tidal tensor. The reconstructed velocity field nicely shows how the flows are diverging from the centres of voids, and converging on to clusters, while sheets and filaments have flows that are convergent along one and two directions, respectively. We use the reconstructed velocity field and the Zel'dovich approximation to predict the mass density field in the SDSS volume as function of redshift, and find that the mass distribution closely follows the galaxy distribution even on small scales. We find a large-scale bulk flow of about 117kms -1 in a very large volume, equivalent to a sphere with a radius of ~170h -1Mpc, which seems to be produced by the massive structures associated with the SDSS Great Wall. Finally, we discuss potential applications of our reconstruction to study the environmental effects of galaxy formation, to generate initial conditions for simulations of the local Universe, and to constrain cosmological models. The velocity, tidal and density fields in the SDSS volume, specified on a Cartesian grid with a spatial resolution of ~700h -1kpc, are available from the authors upon request. © 2011 The Authors Monthly Notices of the Royal Astronomical Society © 2011 RAS.

Liang H.-W.,Anhui University of Science and Technology | Zhang W.-J.,Anhui University of Science and Technology | Ma Y.-N.,Anhui University of Traditional Chinese Medicine | Cao X.,Anhui University of Science and Technology | And 3 more authors.
ACS Nano | Year: 2011

Translating the unique characteristics of individual nanoscale components into macroscopic materials such as membranes or sheets still remains a challenge, as the engineering of these structures often compromises their intrinsic properties. Here, we demonstrate that the highly active carbonaceous nanofibers (CNFs), which are prepared through a template-directed hydrothermal carbonization process, can be used as a versatile nanoscale scaffold for constructing macroscopic multifunctional membranes. In order to demonstrate the broad applicability of the CNF scaffold, we fabricate a variety of CNF-based composite nanofibers, including CNFs-Fe3O4, CNFs-TiO 2, CNFs-Ag, and CNFs-Au through various chemical routes. Importantly, all of them inherit unique dimensionality (high aspect ratio) and mechanical properties (flexibility) of the original CNF scaffolds and thus can be assembled into macroscopic free-standing membranes through a simple casting process. We also demonstrate the wide application potentials of these multifunctional composite membranes in magnetic actuation, antibiofouling filtration, and continuous-flow catalysis. © 2011 American Chemical Society.

Giunti C.,National Institute of Nuclear Physics, Italy | Laveder M.,University of Padua | Li Y.F.,CAS Institute of High Energy Physics | Long H.W.,Anhui University of Science and Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We discuss the implications for short-baseline electron neutrino disappearance in the 3+1 mixing scheme of the recent Troitsk bounds on the mixing of a neutrino with mass between 2 and 100 eV. Considering the Troitsk data in combination with the results of short-baseline νe and ν̄e disappearance experiments, which include the reactor and Gallium anomalies, we derive a 2σ allowed range for the effective neutrino squared-mass difference between 0.85 and 43 eV2. The upper bound implies that it is likely that oscillations in distance and/or energy can be observed in radioactive source experiments. It is also favorable for the ICARUS@CERN experiment, in which it is likely that oscillations are not washed out in the near detector. We discuss also the implications for neutrinoless double-β decay. © 2013 American Physical Society.

Giunti C.,National Institute of Nuclear Physics, Italy | Laveder M.,University of Padua | Li Y.F.,CAS Institute of High Energy Physics | Long H.W.,Anhui University of Science and Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We present the results of global analyses of short-baseline neutrino oscillation data in 3+1, 3+2 and 3+1+1 neutrino mixing schemes. We show that the data do not allow us to abandon the simplest 3+1 scheme in favor of the more complex 3+2 and 3+1+1 schemes. We present the allowed region in the 3+1 parameter space, which is located at Δm412 between 0.82 and 2.19 eV2 at 3σ. The case of no oscillations is disfavored by about 6σ, which decreases dramatically to about 2σ if the Liquid Scintillating Neutrino Detector (LSND) data are not considered. Hence, new high-precision experiments are needed to check the LSND signal. © 2013 American Physical Society.

Huang F.,Anhui University of Science and Technology | Xu H.,Anhui University of Science and Technology | Tan W.,University of Florida | Tan W.,Hunan University | Liang H.,Anhui University of Science and Technology
ACS Nano | Year: 2014

The immobilization of DNA molecules onto a solid support is a crucial step in biochip research and related applications. In this work, we report a DNA photolithography method based on photocleavage of 2-nitrobenzyl linker-modified DNA strands. These strands were subjected to ultraviolet light irradiation to generate multiple short DNA strands in a programmable manner. Coupling the toehold-mediated DNA strand-displacement reaction with DNA photolithography enabled the fabrication of a DNA chip surface with multifunctional DNA patterns having complex geometrical structures at the microscale level. The erasable DNA photolithography strategy was developed to allow different paintings on the same chip. Furthermore, the asymmetrical modification of colloidal particles was carried out by using this photolithography strategy. This strategy has broad applications in biosensors, nanodevices, and DNA-nanostructure fabrication. © 2014 American Chemical Society.

Zhang M.,Anhui University of Science and Technology | Wen L.,State University of New York at Stony Brook
Geophysical Research Letters | Year: 2013

Using North Korea's 2009 nuclear test as reference and satellite imagery, we show that the location and yield of North Korea's 2013 nuclear test can be quickly and accurately determined based on seismic data. North Korea's 2013 nuclear test site is pinpointed by deriving relative location of North Korea's 2009 and 2013 nuclear tests and using the previously determined location of the 2009 nuclear test, while its yield is estimated based on the relative amplitude ratios of the Lg waves recorded for both events, the previously determined Lg-magnitude of 2009 nuclear test and burial depth inferred from satellite imagery. North Korea's 2013 test site is determined to be located at (41°17'26.88 N, 129°4'34.68 E), about 345 m south and 453 m west of its 2009 nuclear test site, with a geographic precision of 94 m. Its yield is estimated to be 12.2 - 3.8 kt. Key Points North Korea's 2013 test site is determined with a geographic precision of 94 m Its yield is estimated to be 12.2 {plus minus} 3.8 kt Suggests a way to quickly and accurately determine location and yield ©2013. American Geophysical Union. All Rights Reserved.

Giunti C.,National Institute of Nuclear Physics, Italy | Laveder M.,University of Padua | Li Y.F.,CAS Institute of High Energy Physics | Liu Q.Y.,Anhui University of Science and Technology | Long H.W.,Anhui University of Science and Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

We present a complete update of the analysis of νe and ν̄e disappearance experiments in terms of neutrino oscillations in the framework of 3+1 neutrino mixing, taking into account the Gallium anomaly, the reactor anomaly, solar neutrino data, and νeC scattering data. We discuss the implications of a recent Ga71(He3,H3)Ge71 measurement which give information on the neutrino cross section in Gallium experiments. We discuss the solar bound on active-sterile mixing and present our numerical results. We discuss the connection between the results of the fit of neutrino oscillation data and the heavy neutrino mass effects in β-decay experiments (considering new Mainz data) and neutrinoless double-β decay experiments (considering the recent EXO results). © 2012 American Physical Society.

Yin L.,University of Florida | Xia J.S.,University of Florida | Takano Y.,University of Florida | Sullivan N.S.,University of Florida | And 2 more authors.
Physical Review Letters | Year: 2013

By means of ac magnetic-susceptibility measurements, we find evidence for a new magnetic phase of Tb2Ti2O7 below about 140 mK in zero magnetic field. In magnetic fields parallel to [111], this phase is characterized by frequency- and amplitude-dependent susceptibility and extremely slow spin dynamics. In the zero-temperature limit, it extends to about 67 mT (the internal field Hint≲52 mT), at which it makes transition to another phase. The field dependence of the susceptibility of this second phase, which extends to about 0.60 T (Hint≲0.54 T) in the zero-temperature limit, indicates the presence of a weak magnetization plateau below about 50 mK, as has been predicted by a single-tetrahedron four-spin model, suggesting that the second phase is a quantum kagome ice. © 2013 American Physical Society.

Wang S.-J.,China University of Geosciences | Li S.-G.,China University of Geosciences | Li S.-G.,Anhui University of Science and Technology | Liu S.-A.,China University of Geosciences
Earth and Planetary Science Letters | Year: 2013

We for the first time reported low-δ18O granites within craton in Bengbu uplift, southeast margin of North China Craton. Integrated ion microprobe study of δ18O and U-Pb age on single zircon grains and zircon populations, gives direct evidence for the origin and later magmatic evolution of the low-δ18O granites. Three types of zircon domains are recognized: inherited magmatic core (Type I), inherited metamorphic core/mantle (Type II) and overgrown magmatic rim (Type III). Type I zircons were formed in Neoproterozoic, and have the average δ18O values of 5.3±0.6‰ around mantle value. Triassic Type II zircons have extremely low and highly heterogeneous δ18O values ranging from -9.4‰ to 8.6‰, consistent with the values and variations exhibited by metamorphic zircons from Dabie-Sulu orogen. This feature argues for a Triassic metamorphic origin for the 18O-depletion signature of zircons from ultrahigh pressure metamorphic rocks in Dabie-Sulu orogen. Jurassic Type III zircons have isotopically homogeneous δ18O values of 3.3±0.5‰. Collectively, zircon populations recorded the δ18O variations from source to low-δ18O granite. The primary protolith of Jurassic granites in Bengbu uplift is a Neoproterozoic granitic intrusion in South China Block. Later high-temperature meteoric hydrothermal alteration has lowered the whole-rock δ18O values in various degrees. The low-δ18O protolith was then buried to the middle-lower crust by Triassic continental subduction and Jurassic anatexis produced the low-δ18O granitic magma. Moreover, δ18O values of Type III zircons are isotopically lighter than previously reported values of magmatic garnets in Jurassic granites, indicating later magmatic evolution of low-δ18O magma toward high δ18O values probably as a result of infiltration of high-δ18O fluid from wall-rocks. © 2013.

Li S.,Wenzhou University | Chen P.,Anhui University | Zhang L.,Wenzhou University | Liang H.,Anhui University of Science and Technology
Langmuir | Year: 2011

The geometric frustration phases are investigated for diblock copolymers in nanoparticles with neutral surfaces using real-space self-consistent field theory. First, a rich variety of geometric frustration phases with specific symmetries are observed in the polymer nanoparticles with invariable diameters by constructing the phase diagrams arranged as the volume fraction and Flory-Huggins interaction parameter. Most of the space in the phase diagram is filled with phases with strong symmetries, such as spherical or cubic symmetries, while a number of asymmetric or axisymmetric phases are located in a narrow space in the diagram. Then the geometric frustration phases are examined systematically for the diblock copolymers with special polymer parameters, and a rich variety of novel frustration phases with multilayered structures are observed by varying the diameters of the nanoparticles. Furthermore, the investigations on the free energies indicate that the transitions between these frustrated phases are first-order, and the formation mechanism of the frustration phases is reasonably elucidated. © 2011 American Chemical Society.

Zhang H.,Zhejiang University | Jin M.,Xi'an University of Science and Technology | Xiong Y.,Anhui University of Science and Technology | Lim B.,Sungkyunkwan University | Xia Y.,Georgia Institute of Technology
Accounts of Chemical Research | Year: 2013

Palladium is a marvelous catalyst for a rich variety of reactions in industrial processes and commercial devices. Most Pd-catalyzed reactions exhibit structure sensitivity, meaning that the activity or selectivity depends on the arrangement of atoms on the surface. Previously, such reactions could only be studied in ultrahigh vacuum using Pd single crystals cut with a specific crystallographic plane. However, these model catalysts are far different from real catalytic systems owing to the absence of atoms at corners and edges and the extremely small specific surface areas for the model systems. Indeed, enhancing the performance of a Pd-based catalyst, in part to reduce the amount needed of this precious and rare metal for a given reaction, requires the use of Pd with the highest possible specific surface area. Recent advances in nanocrystal synthesis are offering a great opportunity to investigate and quantify the structural sensitivity of catalysts based on Pd and other metals. For a structure-sensitive reaction, the catalytic properties of Pd nanocrystals are strongly dependent on both the size and shape. The shape plays a more significant role in controlling activity and selectivity, because the shape controls not only the facets but also the proportions of surface atoms at corners, edges, and planes, which affect the outcomes of possible reactions. We expect catalysts based on Pd nanocrystals with optimized shapes to meet the increasing demands of industrial applications at reduced loadings and costs.In this Account, we discuss recent advances in the synthesis of Pd nanocrystals with controlled shapes and their resulting performance as catalysts for a large number of reactions. First, we review various synthetic strategies based on oxidative etching, surface capping, and kinetic control that have been used to direct the shapes of nanocrystals. When crystal growth is under thermodynamic control, the capping agent plays a pivotal role in determining the shape of a product by altering the order of surface energies for different facets through selective adsorption; the resulting product has the lowest possible total surface energy. In contrast, the product of a kinetically controlled synthesis often deviates from the thermodynamically favored structure, with notable examples including nanocrystals enclosed by high-index facets or concave surfaces.We then discuss the key parameters that control the nucleation and growth of Pd nanocrystals to decipher potential growth mechanisms and build a connection between the experimental conditions and the pathways to different shapes. Finally, we present a number of examples to highlight the use of these Pd nanocrystals as catalysts or electrocatalysts for various applications with structure-sensitive properties. We believe that a deep understanding of the shape-dependent catalytic properties, together with an ability to experimentally maneuver the shape of metal nanocrystals, will eventually lead to rational design of advanced catalysts with substantially enhanced performance. © 2012 American Chemical Society.

Chen S.,Suzhou University of Science and Technology | Su H.,Suzhou University of Science and Technology | Wang Y.,Suzhou University of Science and Technology | Wu W.,Anhui University of Science and Technology | Zeng J.,Suzhou University of Science and Technology
Angewandte Chemie - International Edition | Year: 2015

Mastery over the structure of materials at nanoscale can effectively tailor and control their catalytic properties, enabling enhancement in both activity and durability. We report a size-controlled synthesis of novel Pt-Cu hierarchical trigonal bipyramid nanoframes (HTBNFs). The obtained nanocrystals looked like a trigonal bipyramid on the whole, composed of similar ordered frame structural units. By varying the amount of KI involved in the reaction, HTBNFs with variable sizes from 110 to 250 nm could be obtained. In addition, the structure of HTBNFs could be preserved only in a limited range of the Pt/Cu feeding ratio. Relative to the commercial Pt/C, these Pt-Cu HTBNFs with different Pt/Cu ratio exhibited enhanced electrocatalytic activity toward formic acid oxidation reaction as much as 5.5 times in specific activity and 2.1 times in mass activity. The excellent electrocatalytic activity and better durability are due to the unique structure of HTBNFs and probably synergetic effects between Pt and Cu. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bao C.,Anhui University of Science and Technology | Guo Y.,Anhui University of Science and Technology | Song L.,Anhui University of Science and Technology | Hu Y.,Anhui University of Science and Technology | Hu Y.,Suzhou University of Science and Technology
Journal of Materials Chemistry | Year: 2011

Polymer/graphene nanocomposites have generated intensive interest due to their unique properties. Dispersion and interface interactions between graphene and the polymer matrix are two key factors to obtain property enhancements. According to the open literature, in poly(vinyl alcohol) (PVA) nanocomposites, graphene usually obtains more significant property enhancements than graphite oxide (GO), although GO can much more easily form a good dispersion and strong interaction in the PVA matrix because of its oxygenated functionalities, and the reason has not been well documented yet. In this work, graphene and GO were successfully incorporated into PVA; the properties and the mechanism for the property enhancements were investigated. GO formed better dispersion and exfoliation while graphene caused more property enhancements including mechanical properties, electrical conductivity and thermal stability. The mechanical strength of the graphene/GO nano-layers is attributed to be the fundamental cause for the enhancements in crystallinity and mechanical properties; the hydrogen bond among the PVA molecules is the key factor to influence the glass transition temperatures; the hydrogen bond between the graphene/GO nano-layers and PVA matrix is the decisive factor for the exfoliation and dispersion of graphene/GO; the conducting network is the explanation for the increased electrical conductivity; the physical barrier effect of graphene nano-sheets is the main cause for improved thermal stability. This work investigates the mechanisms for property enhancements, clarifies the roles of the hydrogen bond and the mechanical strength of the graphene/GO nano-layers, and explains why graphene usually achieves more property enhancements than GO. © 2011 The Royal Society of Chemistry.

Wu M.,University of Nebraska - Lincoln | Wu X.,Anhui University of Science and Technology | Pei Y.,Xiangtan University | Zeng X.C.,University of Nebraska - Lincoln
Nano Research | Year: 2011

We have investigated the electronic and structural properties of inorganic nanoribbons (BN, AlN, GaN, SiC, and ZnO) with unpassivated zigzag edges using density functional theory calculations. We find that, in general, the unpassivated zigzag edges can lead to spin-splitting of energy bands. More interestingly, the inorganic nanoribbons AlN and SiC with either one or two edges unpassivated are predicted to be half metallic. Possible structural reconstruction at the unpassivated edges and its effect on the electronic properties are investigated. The unpassivated N edge in the BN nanoribbon and P edge in the AlP nanoribbon are energetically less stable than the corresponding reconstructed edge. Hence, edge reconstruction at the two edges may occur at high temperatures. Other unpassivated edges of the inorganic nanoribbons considered in this study are all robust against edge reconstruction. © 2011 Tsinghua University Press and Springer-Verlag Berlin Heidelberg.

Wang S.-J.,China University of Geosciences | Wang S.-J.,University of Washington | Teng F.-Z.,University of Washington | Li S.-G.,China University of Geosciences | Li S.-G.,Anhui University of Science and Technology
Nature Communications | Year: 2014

Subduction of carbonates and carbonated eclogites into the mantle plays an important role in transporting carbon into deep Earth. However, to what degree isotopic exchanges occur between carbonate and silicate during subduction remains unclear. Here we report Mg and O isotopic compositions for ultrahigh pressure metamorphic marbles and enclosed carbonated eclogites from China. These marbles include both calcite- and dolomite-rich examples and display similar O but distinct Mg isotopic signatures to their protoliths. Their δ 26 Mg values vary from -2.508 to -0.531‰, and negatively correlate with MgO/CaO ratios, unforeseen in sedimentary carbonates. Carbonated eclogites have extremely heavy δ 18 O (up to +21.1‰) and light δ 26 Mg values (down to -1.928‰ in garnet and -0.980‰ in pyroxene) compared with their protoliths. These unique Mg-O isotopic characteristics reflect differential isotopic exchange between eclogites and carbonates during subduction, making coupled Mg and O isotopic studies potential tools for tracing deep carbon recycling. © 2014 Macmillan Publishers Limited. All rights reserved.

Teng F.-Z.,University of Arkansas | Li W.-Y.,University of Arkansas | Li W.-Y.,Anhui University of Science and Technology | Rudnick R.L.,University of Maryland University College | Gardner L.R.,University of South Carolina
Earth and Planetary Science Letters | Year: 2010

Magnesium isotopic compositions of a profile through saprolites developed on a diabase dike from South Carolina have been measured in order to study the behavior of Mg isotopes during continental weathering. As weathering progresses, Mg isotopes are greatly fractionated and are correlated with Mg concentration, clay mineral proportions and density of the saprolites δ26Mg values increase from -0.22 in the unweathered diabase to +0.65 in the most weathered saprolite. These observations are consistent with the release of light Mg to the hydrosphere and formation of isotopically heavy Mg in the weathered products. The loss of Mg during weathering can be modeled by Rayleigh distillation with an apparent fractionation factor between the saprolite and fluid (α) of 1.00005 to 1.0004, i.e., up to 0.4‰fractionation in the 26Mg/24Mg ratio between the saprolite and fluid. The large variation in α value reflects a mineralogical control on Mg isotope fractionation during primary dissolution of Mg-rich minerals and formation of secondary minerals during continental weathering. Like Mg isotopes, Li isotopes in the saprolite profile are also greatly fractionated, with δ7Li values ranging from -6.7 down to -20. The large Li isotope fractionation and variation in Li concentration, as well as irregularities in the δ7Li profile with depth, however, cannot be explained by Li loss during weathering alone. Instead, Li can be modeled by a two-step process: (1) equilibrium isotope fractionation during continental weathering, which lowered δ7Li and Li concentrations and produced a Li concentration gradient in the saprolites like that seen in Mg, and (2) subsequent kinetic isotope fractionation produced by diffusion of Li in the saprolites, possibly across a paleo-water table. The results presented here suggest that continental weathering will shift the Mg isotopic composition of the continental crust to values higher than the mantle value, whereas crustal recycling over the history of the Earth will have no discernible effect on the Mg isotopic composition of the mantle. © 2010 Elsevier B.V.

Li P.,Huaibei Normal University | Li P.,Anhui University of Science and Technology | Wang L.,Huaibei Normal University | Wang L.,CAS Shanghai Institute of Organic Chemistry | And 2 more authors.
Advanced Synthesis and Catalysis | Year: 2012

A highly efficient, air- and moisture-stable and easily recoverable magnetic nanoparticle-supported palladium catalyst has been developed for the Suzuki, Sonogashira and Heck reactions. A wide range of substrates was coupled successfully under aerobic conditions. In particular, the performance of the magnetic separation of the catalyst was very efficient, and it is possible to recover and reuse it at least eight times without significant loss of its catalytic activity. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Culcer D.,Anhui University of Science and Technology | Das Sarma S.,University of Maryland University College
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

The anomalous Hall effect due to the surface conduction band of three-dimensional topological insulators with an out-of-plane magnetization is always dominated by an intrinsic topological term of the order of the conductivity quantum. We determine the contributions due to the band structure, skew scattering, side jump, and magnetic impurities on the same footing, demonstrating that the topological term, renormalized due to disorder, overwhelms all other terms, providing an unmistakable signature of Z2 topological order. Uncharacteristically, skew scattering contributes in the Born approximation as well as in the third order in the scattering potential, while in addition to the side-jump scattering term we identify a different intrinsic side-jump term of a similar magnitude. These, however, never overwhelm the topological contribution. © 2011 American Physical Society.

Culcer D.,Anhui University of Science and Technology | Saraiva A.L.,Federal University of Rio de Janeiro | Koiller B.,Federal University of Rio de Janeiro | Hu X.,State University of New York at Buffalo | Das Sarma S.,University of Maryland University College
Physical Review Letters | Year: 2012

We devise a platform for noise-resistant quantum computing using the valley degree of freedom of Si quantum dots. The qubit is encoded in two polarized (1,1) spin-triplet states with different valley compositions in a double quantum dot, with a Zeeman field enabling unambiguous initialization. A top gate gives a difference in the valley splitting between the dots, allowing controllable interdot tunneling between opposite valley eigenstates, which enables one-qubit rotations. Two-qubit operations rely on a stripline resonator, and readout on charge sensing. Sensitivity to charge and spin fluctuations is determined by intervalley processes and is greatly reduced as compared to conventional spin and charge qubits. We describe a valley echo for further noise suppression. © 2012 American Physical Society.

Yuan J.,Anhui University of Science and Technology | Zheng Y.,Microsoft | Xie X.,Microsoft | Sun G.,Anhui University of Science and Technology
IEEE Transactions on Knowledge and Data Engineering | Year: 2013

This paper presents a smart driving direction system leveraging the intelligence of experienced drivers. In this system, GPS-equipped taxis are employed as mobile sensors probing the traffic rhythm of a city and taxi drivers' intelligence in choosing driving directions in the physical world. We propose a time-dependent landmark graph to model the dynamic traffic pattern as well as the intelligence of experienced drivers so as to provide a user with the practically fastest route to a given destination at a given departure time. Then, a Variance-Entropy-Based Clustering approach is devised to estimate the distribution of travel time between two landmarks in different time slots. Based on this graph, we design a two-stage routing algorithm to compute the practically fastest and customized route for end users. We build our system based on a real-world trajectory data set generated by over 33,000 taxis in a period of three months, and evaluate the system by conducting both synthetic experiments and in-the-field evaluations. As a result, 60-70 percent of the routes suggested by our method are faster than the competing methods, and 20 percent of the routes share the same results. On average, 50 percent of our routes are at least 20 percent faster than the competing approaches. © 1989-2012 IEEE.

Cheng J.L.,Anhui University of Science and Technology | Cheng J.L.,University of Regensburg | Wu M.W.,Anhui University of Science and Technology | Fabian J.,University of Regensburg
Physical Review Letters | Year: 2010

A realistic pseudopotential model is introduced to investigate the phonon-induced spin relaxation of conduction electrons in bulk silicon. We find a surprisingly subtle interference of the Elliott and Yafet processes affecting the spin relaxation over a wide temperature range, suppressing the significance of the intravalley spin-flip scattering, previously considered dominant, above roughly 120 K. The calculated spin relaxation times T1 agree with the spin resonance and spin injection data, following a T-3 temperature dependence. The valley anisotropy of T1 and the spin relaxation rates for hot electrons are predicted. © 2010 The American Physical Society.

Chen P.,Anhui University of Science and Technology | Ding G.-J.,Anhui University of Science and Technology | Gonzalez-Canales F.,University of Valencia | Valle J.W.F.,University of Valencia
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2016

We propose a generalized μ-τ reflection symmetry to constrain the lepton flavor mixing parameters. We obtain a new correlation between the atmospheric mixing angle θ23 and the "Dirac" CP violation phase δCP. Only in a specific limit our proposed CP transformation reduces to standard μ-τ reflection, for which θ23 and δCP are both maximal. The "Majorana" phases are predicted to lie at their CP-conserving values with important implications for the neutrinoless double beta decay rates. We also study the phenomenological implications of our scheme for present and future neutrino oscillation experiments including T2K, NOνA and DUNE. © 2015 The Authors.

Guan M.,Anhui University of Science and Technology | Xiao C.,Anhui University of Science and Technology | Zhang J.,Anhui University of Science and Technology | Fan S.,Anhui University of Science and Technology | And 6 more authors.
Journal of the American Chemical Society | Year: 2013

Crystal facet engineering of semiconductors is of growing interest and an important strategy for fine-tuning solar-driven photocatalytic activity. However, the primary factor in the exposed active facets that determines the photocatalytic property is still elusive. Herein, we have experimentally achieved high solar photocatalytic activity in ultrathin BiOCl nanosheets with almost fully exposed active {001} facets and provide some new and deep-seated insights into how the defects in the exposed active facets affect the solar-driven photocatalytic property. As the thickness of the nanosheets reduces to atomic scale, the predominant defects change from isolated defects VBi‴ to triple vacancy associates VBi‴VO••VBi‴, which is unambiguously confirmed by the positron annihilation spectra. By virtue of the synergic advantages of enhanced adsorption capability, effective separation of electron-hole pairs and more reductive photoexcited electrons benefited from the VBi‴VO••VBi‴ vacancy associates, the ultrathin BiOCl nanosheets show significantly promoted solar-driven photocatalytic activity, even with extremely low photocatalyst loading. The finding of the existence of distinct defects (different from those in bulks) in ultrathin nanosheets undoubtedly leads to new possibilities for photocatalyst design using quasi-two-dimensional materials with high solar-driven photocatalytic activity. © 2013 American Chemical Society.

Xie J.,Anhui University of Science and Technology | Zhang J.,Anhui University of Science and Technology | Li S.,Anhui University of Science and Technology | Grote F.,TU Ilmenau | And 6 more authors.
Journal of the American Chemical Society | Year: 2013

Molybdenum disulfide (MoS2) has emerged as a promising electrocatalyst for catalyzing protons to hydrogen via the so-called hydrogen evolution reaction (HER). In order to enhance the HER activity, tremendous effort has been made to engineer MoS2 catalysts with either more active sites or higher conductivity. However, at present, synergistically structural and electronic modulations for HER still remain challenging. In this work, we demonstrate the successfully synergistic regulations of both structural and electronic benefits by controllable disorder engineering and simultaneous oxygen incorporation in MoS2 catalysts, leading to the dramatically enhanced HER activity. The disordered structure can offer abundant unsaturated sulfur atoms as active sites for HER, while the oxygen incorporation can effectively regulate the electronic structure and further improve the intrinsic conductivity. By means of controllable disorder engineering and oxygen incorporation, an optimized catalyst with a moderate degree of disorder was developed, exhibiting superior activity for electrocatalytic hydrogen evolution. In general, the optimized catalyst exhibits onset overpotential as low as 120 mV, accompanied by extremely large cathodic current density and excellent stability. This work will pave a new pathway for improving the electrocatalytic activity by synergistically structural and electronic modulations. © 2013 American Chemical Society.

Zhang W.,Anhui University of Science and Technology | Hua Z.,Anhui University of Science and Technology | Benjaafar S.,University of Minnesota
Production and Operations Management | Year: 2012

We consider a dual-sourcing inventory system, where procuring from one supplier involves a high variable cost but negligible fixed cost whereas procuring from the other supplier involves a low variable cost but high fixed cost, as well as an order size constraint. We show that the problem can be reduced to an equivalent single-sourcing problem. However, the corresponding ordering cost is neither concave nor convex. Using the notion of quasi-convexity, we partially characterize the structure of the optimal policy and show that it can be specified by multiple thresholds which determine when to order from each supplier and how much. In contrast to previous research, which does not consider order size constraints, we show that it is optimal to simultaneously source from both suppliers when the beginning inventory level is sufficiently low. We also show that the decision to source from the low-cost supplier is not monotonic in the inventory level. Our results require that the variable costs satisfy a certain condition which guarantees quasi-convexity. However, extensive numerical results suggest that our policy is almost always optimal when the condition is not satisfied. We also show how the results can be extended to systems with multiple capacitated suppliers. © 2011 Production and Operations Management Society.

Shu X.W.,Anhui University of Science and Technology | Yaqoob T.,Johns Hopkins University | Wang J.X.,Anhui University of Science and Technology
Astrophysical Journal | Year: 2011

We present a study of the core of the FeKα emission line at ∼6.4keV in a sample of type II Seyfert galaxies observed by the Chandra high-energy grating. The sample consists of 29 observations of 10 unique sources. We present measurements of the FeKα line parameters with the highest spectral resolution currently available. In particular, we derive the most robust intrinsic line widths for some of the sources in the sample to date. We obtained a weighted mean full width at half-maximum (FWHM) of 2000 ± 160 km s-1 for 8 out of 10 sources (the remaining sources had insufficient signal to noise). From a comparison with the optical emission-line widths obtained from spectropolarimetric observations, we found that the location of FeKα line-emitting material is a factor of ∼0.7-11 times the size of the optical broad-line region. Furthermore, compared to 13 type I active galactic nuclei (AGNs) for which the best FeKα line FWHM constraints were obtained, we found no difference in the FWHM distribution or the mean FWHM, and this conclusion is independent of the central black hole mass. This result suggests that the bulk of the FeKα line emission may originate from a universal region at the same radius with respect to the gravitational radius, ∼3 × 104 rg on average. By examining the correlation between the FeKα luminosity and the [O IV] line luminosity, we found a marginal difference in the FeKα line flux between type I and type II AGNs, but the spread in the ratio of L Fe to L [O IV]is about two orders of magnitude. Our results confirm the theoretical expectation that the FeKα emission-line luminosity cannot trivially be used as a proxy of the intrinsic AGN luminosity, unless a detailed comparison of the data with proper models is applied. © 2011. The American Astronomical Society. All rights reserved.

Wu Z.,University of Minnesota | Wu Z.,Anhui University of Science and Technology | Wentzcovitch R.M.,University of Minnesota
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

First-principles quasiharmonic calculations play a very important role in mineral physics because they can predict the structural and thermodynamic properties of materials at pressure and temperature conditions of the Earth's interior that are still challenging for experiments. They also enable calculations of thermal elastic properties by providing second-order derivatives of free energies with respect to strain. The latter are essential to interpret seismic tomography of the mantle in terms of temperature, composition, and mineralogy, in the context of geophysical processes. However, these are exceedingly demanding computations requiring up to ∼103 parallel jobs running on tens or more processors each. Here we introduce an analytical and computationally simpler approach that requires only calculations of static elastic constants and phonon density of states for unstrained configurations. This approach, currently implemented for crystals with up to orthorhombic symmetry, decreases the computational effort, i.e., CPU time and human labor, by up to two orders of magnitude. Results for the major mantle phases periclase (MgO) and forsterite (α-Mg2SiO4) show excellent agreement with previous first-principles results and experimental data. © 2011 American Physical Society.

Wu F.,Anhui University of Science and Technology | Deng Y.,Anhui University of Science and Technology | Deng Y.,University of Massachusetts Amherst | Prokof'Ev N.,University of Massachusetts Amherst
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

Ground-state phase diagram of the toric code model in a parallel magnetic field has three distinct phases: topological, charge-condensed, and vortex-condensed states. To study it we consider an implicit local order parameter characterizing the transition between the topological and charge-condensed phases, and sample it using continuous-time Monte Carlo simulations. The corresponding second-order transition line is obtained by finite-size scaling analysis of this order parameter. Symmetry breaking between charges and vortices along the first-order transition line is also observed, and our numerical result shows that the end point of the first-order transition line is located at hx(c)=hz(c)=0.418(2). © 2012 American Physical Society.

Wu F.,Anhui University of Science and Technology | Wu F.,University of Massachusetts Amherst | Zilberstein S.,University of Massachusetts Amherst | Chen X.,Anhui University of Science and Technology
Artificial Intelligence | Year: 2011

We propose an online algorithm for planning under uncertainty in multi-agent settings modeled as DEC-POMDPs. The algorithm helps overcome the high computational complexity of solving such problems offline. The key challenges in decentralized operation are to maintain coordinated behavior with little or no communication and, when communication is allowed, to optimize value with minimal communication. The algorithm addresses these challenges by generating identical conditional plans based on common knowledge and communicating only when history inconsistency is detected, allowing communication to be postponed when necessary. To be suitable for online operation, the algorithm computes good local policies using a new and fast local search method implemented using linear programming. Moreover, it bounds the amount of memory used at each step and can be applied to problems with arbitrary horizons. The experimental results confirm that the algorithm can solve problems that are too large for the best existing offline planning algorithms and it outperforms the best online method, producing much higher value with much less communication in most cases. The algorithm also proves to be effective when the communication channel is imperfect (periodically unavailable). These results contribute to the scalability of decision-theoretic planning in multi-agent settings. © 2010 Elsevier B.V. All rights reserved.

Punsly B.,4014 Emerald Street No.116 | Zhang S.,Anhui University of Science and Technology
Astrophysical Journal | Year: 2010

There is evidence from radio-loud quasars to suggest that the distribution of the Hβ broad emission line (BEL) gas is arranged in a predominantly planar orientation, and this result may well also apply to radio-quiet quasars. This would imply that the observed FWHM of the Hβ BELs is dependent on the orientation of the line of sight to the gas. If this view is correct then we propose that the FWHM can be used as a surrogate, in large samples, to determine the line of sight to the Hβ BELs in broad absorption line quasars (BALQSOs). The existence of broad UV absorption lines (BALs) means that the line of sight to BALQSOs must also pass through the BAL out-flowing gas. It is determined that there is a statistically significant excess of narrow-line profiles in the SDSS DR7 archival spectra of low-ionization broad absorption line quasars (LoBALQSOs), indicating that BAL gas flowing close to the equatorial plane does not commonly occur in these sources. We also find that the data is not well represented by random lines of sight to the BAL gas. Our best fit indicates two classes of LoBALQSOs, the majority (≈2/3) are polar outflows that are responsible for the enhanced frequency of narrowline profiles, and the remainder are equatorial outflows. We further motivated the line of sight explanation of the narrow-line excess in LoBALQSOs by considering the notion that the skewed distribution of line profiles is driven by an elevated Eddington ratio in BALQSOs. We constructed a variety of control samples comprised of non-LoBALQSOs matched to a de-reddened LoBALQSO sample in redshift, luminosity, black hole mass, and Eddington ratio. It is demonstrated that the excess of narrow profiles persists within the LoBALQSO sample relative to each of the control samples with no reduction of the statistical significance. Thus, we eliminate the possibility that the excess narrow lines seen in the LoBALQSOs arise from an enhanced Eddington ratio. © 2010. The American Astronomical Society. All rights reserved.

Du X.,University of Massachusetts Amherst | Dubin P.L.,University of Massachusetts Amherst | Hoagland D.A.,University of Massachusetts Amherst | Sun L.,Anhui University of Science and Technology
Biomacromolecules | Year: 2014

Selective coacervation with hyaluronic acid (HA), a biocompatible and injectable anionic polysaccharide, was used to isolate a target protein, bovine serum albumin (BSA), with 90% purity from a 1:1 mixture with a second protein of similar pI, β-lactoglobulin (BLG). This separation was attributed to the higher HA-affinity of BSA, arising from its more concentrated positive domain. The values of pH corresponding respectively to the onset of complex formation, coacervation, precipitation, and redissolution (pHc, pH, pH p, and pHd) were determined as a function of ionic strength I. These pH values were related to critical values of protein charge, Z, and their dependence on I provided some insights into the mechanisms of these transitions. The higher polyanion binding affinity of BSA, deduced from its higher values of pHc, was confirmed by isothermal titration calorimetry (ITC). Confocal laser microscopy clearly showed time-dependent coalescence of vesicular droplets into a continuous film. Comparisons with prior results for the polycation poly(diallyldimethylammonium chloride) (PDADMAC) show reversal of protein selectivity due to reversal of the polyelectrolyte charge. Stronger binding of both proteins to PDADMAC established by ITC may be related to the higher chain flexibility and effective linear charge density of this polycation. © 2014 American Chemical Society.

Shu X.W.,Anhui University of Science and Technology | Shu X.W.,Johns Hopkins University | Yaqoob T.,Johns Hopkins University | Wang J.X.,Anhui University of Science and Technology
Astrophysical Journal, Supplement Series | Year: 2010

We extend the study of the core of the Fe Kα emission line at 6.4keV in Seyfert galaxies reported by Yaqoob & Padmanabhan using a larger sample observed by the Chandra high-energy grating (HEG). The sample consists of 82 observations of 36 unique sources with z < 0.3. Whilst heavily obscured active galactic nuclei are excluded from the sample, these data offer some of the highest precision measurements of the peak energy of the Fe Kα line, and the highest spectral resolution measurements of the width of the core of the line in unobscured and moderately obscured (N H < 1023 cm-2) Seyfert galaxies to date. From an empirical and uniform analysis, we present measurements of the Fe Kα line centroid energy, flux, equivalent width (EW), and intrinsic width (FWHM). The Fe Kα line is detected in 33 sources, and its centroid energy is constrained in 32 sources. In 27 sources, the statistical quality of the data is good enough to yield measurements of the FWHM. We find that the distribution in the line centroid energy is strongly peaked around the value for neutral Fe, with over 80% of the observations giving values in the range 6.38-6.43keV. Including statistical errors, 30 out of 32 sources (94%) have a line centroid energy in the range 6.35-6.47keV. The mean EW, among the observations in which a non-zero lower limit could be measured, was 53 3 eV. The mean FWHM from the subsample of 27 sources was 2060 230 km s-1. The mean EW and FWHM are somewhat higher when multiple observations for a given source are averaged. From a comparison with the Hβ optical emission-line widths (or, for one source, Brα), we find that there is no universal location of the Fe Kα line-emitting region relative to the optical broad-line region (BLR). In general, a given source may have contributions to the Fe Kα line flux from parsec-scale distances from the putative black hole, down to matter a factor 2 closer to the black hole than the BLR. We confirm the presence of the X-ray Baldwin effect, an anti-correlation between the Fe Kα line EW and X-ray continuum luminosity. The HEG data have enabled isolation of this effect to the narrow core of the Fe Kα line. © 2010. The American Astronomical Society. All rights reserved.

Chen X.W.,China Academy of Engineering Physics | He L.L.,Anhui University of Science and Technology | Yang S.Q.,China Academy of Engineering Physics
European Journal of Mechanics, A/Solids | Year: 2010

An engineering model on mass abrasion of kinetic energy penetrator is presented to predict the nose shape and mass loss of the residual projectile after high-speed penetration into concrete. The experimental analysis indicates that the kinetic energy of penetrator (i.e., mass and velocity of projectile) and the hardness of aggregate of concrete significantly affect the mass abrasion of projectile. A theoretical upper limit exists for the mass loss. More general relationship between mass loss and impact function I of projectile is constructed. Graphical discussion declares that the most mass loss occurs on the nose of the projectile and the eroding nose approaches to an ogival shape with a smaller value of caliber-radius-head (CRH). A relative rate of mass abrasion on ogive-nose is further defined and analyzed. The mass loss from abrasion on kinetic energy (KE) penetrator may be evaluated through the variation of nose shape. © 2009 Elsevier Masson SAS. All rights reserved.

Hao Z.,Anhui University of Science and Technology | Zhong S.,State University of New York at Buffalo | Yu N.,Anhui University of Science and Technology
IEEE Transactions on Knowledge and Data Engineering | Year: 2011

Remote data integrity checking is a crucial technology in cloud computing. Recently, many works focus on providing data dynamics and/or public verifiability to this type of protocols. Existing protocols can support both features with the help of a third-party auditor. In a previous work, Seb et al. [1] propose a remote data integrity checking protocol that supports data dynamics. In this paper, we adapt Seb et al.'s protocol to support public verifiability. The proposed protocol supports public verifiability without help of a third-party auditor. In addition, the proposed protocol does not leak any private information to third-party verifiers. Through a formal analysis, we show the correctness and security of the protocol. After that, through theoretical analysis and experimental results, we demonstrate that the proposed protocol has a good performance. © 2006 IEEE.

Stroka K.M.,Johns Hopkins University | Jiang H.,Johns Hopkins University | Jiang H.,Anhui University of Science and Technology | Chen S.-H.,Johns Hopkins University | And 4 more authors.
Cell | Year: 2014

Cell migration is a critical process for diverse (patho)physiological phenomena. Intriguingly, cell migration through physically confined spaces can persist even when typical hallmarks of 2D planar migration, such as actin polymerization and myosin II-mediated contractility, are inhibited. Here, we present an integrated experimental and theoretical approach ("Osmotic Engine Model") and demonstrate that directed water permeation is a major mechanism of cell migration in confined microenvironments. Using microfluidic and imaging techniques along with mathematical modeling, we show that tumor cells confined in a narrow channel establish a polarized distribution of Na +/H+ pumps and aquaporins in the cell membrane, which creates a net inflow of water and ions at the cell leading edge and a net outflow of water and ions at the trailing edge, leading to net cell displacement. Collectively, this study presents an alternate mechanism of cell migration in confinement that depends on cell-volume regulation via water permeation. PaperFlick © 2014 Elsevier Inc.

Jiang F.,Anhui University of Science and Technology | Wang Z.,Anhui University of Science and Technology | Qiao Y.,University of South Carolina | Tang C.,University of South Carolina
Macromolecules | Year: 2013

Thermoplastic elastomers (TPEs) are ever sought using a simple robust synthetic approach. Widely successful first-generation TPEs rely on microphase-separated ABA triblock copolymers (Architecture I). Recent multigraft copolymers represent the second-generation TPEs in which multiple branched rigid segments are dispersed in a rubbery backbone matrix (Architecture II). This paper reports our discovery of the third-generation TPEs that are based on rigid backbone dispersed in a soft grafted matrix. This Architecture III allows the use of random copolymers as side chains to access a wide spectrum of TPEs that cannot be achieved by architecture designs of the first two generations. In this report, random copolymer-grafted cellulose, cellulose-graft-poly(n-butyl acrylate-co-methyl methacrylate) copolymers with only 0.9-3.4 wt % cellulose prepared by activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP), as novel thermoplastic elastomers are investigated. © 2013 American Chemical Society.

Shao L.,Anhui University of Science and Technology | Griffiths P.R.,University of Idaho | Leytem A.B.,U.S. Department of Agriculture
Analytical Chemistry | Year: 2010

The automated quantification of three greenhouse gases, ammonia, methane, and nitrous oxide, in the vicinity of a large dairy farm by open-path Fourier transform infrared (OP/FT-IR) spectrometry at intervals of 5 min is demonstrated. Spectral pretreatment, including the automated detection and correction of the effect of interrupting the infrared beam, is by a moving object, and the automated correction for the nonlinear detector response is applied to the measured interferograms. Two ways of obtaining quantitative data from OP/FT-IR data are described. The first, which is installed in a recently acquired commercial OP/FT-IR spectrometer, is based on classical least-squares (CLS) regression, and the second is based on partial least-squares (PLS) regression. It is shown that CLS regression only gives accurate results if the absorption features of the analytes are located in very short spectral intervals where lines due to atmospheric water vapor are absent or very weak; of the three analytes examined, only ammonia fell into this category. On the other hand, PLS regression works allowed what appeared to be accurate results to be obtained for all three analytes. © 2010 American Chemical Society.

Jiang H.,Johns Hopkins University | Jiang H.,Anhui University of Science and Technology | Sun S.X.,Johns Hopkins University
Biophysical Journal | Year: 2013

In eukaryotic cells, small changes in cell volume can serve as important signals for cell proliferation, death, and migration. Volume and shape regulation also directly impacts the mechanics of cells and tissues. Here, we develop a mathematical model of cellular volume and pressure regulation, incorporating essential elements such as water permeation, mechanosensitive channels, active ion pumps, and active stresses in the cortex. The model can fully explain recent experimental data, and it predicts cellular volume and pressure for several models of cell cortical mechanics. Moreover, we show that when cells are subjected to an externally applied load, such as in an atomic force microscopy indentation experiment, active regulation of volume and pressure leads to a complex cellular response. Instead of the passive mechanics of the cortex, the observed cell stiffness depends on several factors working together. This provides a mathematical explanation of rate-dependent response of cells under force. © 2013 The Authors.

Zhou D.,Xi'an Jiaotong University | Pang L.-X.,Xi'an Technological University | Qi Z.-M.,Anhui University of Science and Technology
Inorganic Chemistry | Year: 2014

x(Ag0.5Bi0.5)MoO4-(1 - x)BiVO4 (0.0 ≤ x ≤ 1.0) ceramics were prepared by using the solid-state reaction technique. Ceramics with x < 0.10 had a monoclinic scheelite structure, while those with >0.10 were tetragonal scheelite solid solutions. This indicates that the phase transformation temperature of BiVO4 was lowered through the formation of a solid solution. The thermal expansion data of the x = 0.08 sample showed that the thermal expansion coefficient was increased suddenly from +8 to +15 ppm/°C at about 60.6°C due to the phase transition. Similarly, a maximum value of microwave dielectric permittivity was revealed at about 65°C for the x = 0.08 sample. All of the ceramics could be well sintered below 700°C. Good microwave dielectric behaviors, with relative permittivity >75 and Qf > 9000 GHz, were obtained in ceramics with compositions near x = 0.10. Both the THz data and the infrared spectra were used to study the intrinsic dielectric behavior of the materials at microwave frequencies. © 2014 American Chemical Society.

Gao Z.,Anhui University of Science and Technology | Meng X.,Anhui University of Science and Technology | Wang G.,Southwest Jiaotong University
Modern Tunnelling Technology | Year: 2014

Taking the seepage body force into consideration, this paper derives the rock stress distribution and plastic zone expressions under the seepage field and analyzes the relationships of the plastic zone range to the porewater pressure, lateral pressure coefficient and the ratio K between the rock mass strength and initial geostress. The results show that the seepage field has an effect on the plastic zone range, but not on its shape. With variation of lateral pressure coefficients and K values, the effect of seepage on the plastic zone range presents anisotropy along different directions. Furthermore, the anisotropic degree decreases gradually with the increase of the lateral pressure coefficient and K value. The lateral pressure coefficient and the K value not only affect the plastic zone range, but also its shape. When K<1, the effect from the lateral pressure coefficient plays an important role. Whereas, rock mass strength plays the leading role when K>1, namely, the plastic zone range decreases gradually with the increase of the rock's compressive strength. Additionally, the plastic zone is more likely to appear at the two sides of the tunnel with a decrease of the lateral pressure coefficient.

Wang J.,Anhui University of Science and Technology | Gong M.,Washington State University | Guo G.-C.,Anhui University of Science and Technology | He L.,Anhui University of Science and Technology
Applied Physics Letters | Year: 2012

Eliminating the fine structure splitting (FSS) of excitons in self-assembled quantum dots (QDs) is essential to the generation of high quality entangled photon pairs. It has been shown that the FSS has a lower bound under uniaxial stress. In this letter, we show by a extended two-level model that the FSS of excitons in a general self-assembled InGaAs/GaAs QD can be fully suppressed via combined stresses along the [110] and [010] directions. The results of the model Hamiltonian are confirmed by atomic empirical pseudopotential calculations. For all the QDs we calculated, the FSS can be tuned to be vanishingly small ( 0.1 μ eV), which is sufficient small for high quality entangled photon emission. © 2012 American Institute of Physics.

Chen X.,Anhui University of Science and Technology | Parker S.G.,University of New South Wales | Zou G.,Anhui University of Science and Technology | Su W.,Anhui University of Science and Technology | Zhang Q.,Anhui University of Science and Technology
ACS Nano | Year: 2010

We report herein the development of a highly robust, quantitative, sensitive, and naked eye colorimetric detection method for different isomers of aromatic compounds using β-CD-modified silver nanoparticle (AgNPs) probes. This assay relies on the distance-dependent optical properties of Ag nanoparticles and the different inclusion binding strength of the aromatic guests to β-CD host. In the presence of different isomers of aromatic compounds, AgNPs could be rapidly induced to aggregate, thereby resulting in apricot-to-red color change. The variety and concentration of different isomers of aromatic compounds could be determined by monitoring with the naked eye or a UV-vis spectrometer. The present detection limit for different isomers of aromatic compounds is 5×10-5 M. We believe that the surface architectures of AgNPs after the introduction of the CD-based host-guest recognition would be applicable for a range of chemical and bioanalytical molecular sensing systems in aqueous media. © 2010 American Chemical Society.

Peng L.,Anhui University of Science and Technology | Peng L.,University of Texas at Austin | Peng X.,Wuhan Institute of Technology | Liu B.,University of Texas at Austin | And 3 more authors.
Nano Letters | Year: 2013

Planar supercapacitors have recently attracted much attention owing to their unique and advantageous design for 2D nanomaterials based energy storage devices. However, improving the electrochemical performance of planar supercapacitors still remains a great challenge. Here we report for the first time a novel, high-performance in-plane supercapacitor based on hybrid nanostructures of quasi-2D ultrathin MnO2/graphene nanosheets. Specifically, the planar structures based on the δ-MnO2 nanosheets integrated on graphene sheets not only introduce more electrochemically active surfaces for absorption/desorption of electrolyte ions, but also bring additional interfaces at the hybridized interlayer areas to facilitate charge transport during charging/discharging processes. The unique structural design for planar supercapacitors enables great performance enhancements compared to graphene-only devices, exhibiting high specific capacitances of 267 F/g at current density of 0.2 A/g and 208 F/g at 10 A/g and excellent rate capability and cycling stability with capacitance retention of 92% after 7000 charge/discharge cycles. Moreover, the high planar malleability of planar supercapacitors makes possible superior flexibility and robust cyclability, yielding capacitance retention over 90% after 1000 times of folding/unfolding. Ultrathin 2D nanomaterials represent a promising material platform to realize highly flexible planar energy storage devices as the power back-ups for stretchable/flexible electronic devices. © 2013 American Chemical Society.

Ding D.-S.,Anhui University of Science and Technology | Zhang W.,Anhui University of Science and Technology | Zhou Z.-Y.,Anhui University of Science and Technology | Shi S.,Anhui University of Science and Technology | And 5 more authors.
Physical Review Letters | Year: 2015

Constructing a quantum memory for a photonic entanglement is vital for realizing quantum communication and network. Because of the inherent infinite dimension of orbital angular momentum (OAM), the photon's OAM has the potential for encoding a photon in a high-dimensional space, enabling the realization of high channel capacity communication. Photons entangled in orthogonal polarizations or optical paths had been stored in a different system, but there have been no reports on the storage of a photon pair entangled in OAM space. Here, we report the first experimental realization of storing an entangled OAM state through the Raman protocol in a cold atomic ensemble. We reconstruct the density matrix of an OAM entangled state with a fidelity of 90.3%±0.8% and obtain the Clauser-Horne-Shimony-Holt inequality parameter S of 2.41±0.06 after a programed storage time. All results clearly show the preservation of entanglement during the storage. © 2015 American Physical Society.

Zhang P.,Renmin University of China | Zhang L.,Renmin University of China | Zhang L.,Anhui University of Science and Technology | Deng Y.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2012

We show that the Bethe-Peierls (BP) boundary condition should be modified for ultracold atoms with spin-orbit (SO) coupling. Moreover, we derive a general form of the modified BP boundary condition, which is applicable to a system with an arbitrary kind of SO coupling. In the modified BP condition, an anisotropic term appears and the interatomic scattering length is normally SO-coupling dependent. For the special system in the current experiments, however, it can be proved that the scattering length is SO-coupling independent, and it takes the same value as in the case without SO coupling. Our result is helpful for the study of both few-body and many-body physics in SO-coupled ultracold gases. © 2012 American Physical Society.

Zhou X.-F.,Anhui University of Science and Technology | Guo G.-C.,Anhui University of Science and Technology | Zhang W.,Renmin University of China | Yi W.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013

We investigate properties of exotic pairing states in a three-dimensional Fermi gas with three-dimensional spin-orbit coupling and an effective Zeeman field. The interplay of spin-orbit coupling, effective Zeeman field, and pairing can lead to first-order phase transitions between different phases, and to interesting nodal superfluid states with gapless surfaces in the momentum space. We then demonstrate that pairing states with zero center-of-mass momentum are unstable against Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) states, with a finite center-of-mass momentum opposite to the direction of the effective Zeeman field. Unlike conventional FFLO states, these FFLO states are induced by the coexistence of spin-orbit coupling and Fermi surface deformation, and have intriguing features like first-order transitions between different FFLO states, nodal FFLO states with gapless surfaces in momentum space, and exotic fully gapped FFLO states. With the recent theoretical proposals for realizing three-dimensional spin-orbit coupling in ultracold atomic gases, our work is helpful for future experimental studies and provides valuable information for the general understanding of pairing physics in spin-orbit-coupled fermionic systems. © 2013 American Physical Society.

Li X.,Brown University | Li X.,Anhui University of Science and Technology
Soft Matter | Year: 2013

The understanding of shape transformations and dynamic behaviors of membrane vesicles is of fundamental importance in biological and physical sciences. In this study, dissipative particle dynamics (DPD) simulations are employed to study the shape transformations of bilayer vesicles formed from amphiphilic diblock copolymers. A plethora of complex vesicle shapes, including some that have not been reported in previous simulation studies on membrane vesicles such as boomerang shapes and a couple of different starfish-shaped vesicles, are obtained in the simulations. These simulated polymer vesicles agree with theoretically derived vesicle shapes based on the bilayer couple model. © 2013 The Royal Society of Chemistry.

Feng M.,University of Pittsburgh | Zhao J.,University of Pittsburgh | Huang T.,University of Pittsburgh | Zhu X.,University of Texas at Austin | And 2 more authors.
Accounts of Chemical Research | Year: 2011

Electronic and optical properties of molecules and molecular solids are traditionally considered from the perspective of the frontier orbitals and their intermolecular interactions. How molecules condense into crystalline solids, however, is mainly attributed to the long-range polarization interaction. In this Account, we show that long-range polarization also introduces a distinctive set of diffuse molecular electronic states, which in quantum structures or solids can combine into nearly-free-electron (NFE) bands. These NFE properties, which are usually associated with good metals, are vividly evident in sp 2 hybridized carbon materials, specifically graphene and its derivatives.The polarization interaction is primarily manifested in the screening of an external charge at a solid/vacuum interface. It is responsible for the universal image potential and the associated unoccupied image potential (IP) states, which are observed even at the He liquid/vacuum interface. The molecular electronic properties that we describe are derived from the IP states of graphene, which float above and below the molecular plane and undergo free motion parallel to it. Rolling or wrapping a graphene sheet into a nanotube or a fullerene transforms the IP states into diffuse atom-like orbitals that are bound primarily to hollow molecular cores, rather than the component atoms. Therefore, we named them the superatom molecular orbitals (SAMOs). Like the excitonic states of semiconductor nanostructures or the plasmonic resonances of metallic nanoparticles, SAMOs of fullerene molecules, separated by their van der Waals distance, can combine to form diatomic molecule-like orbitals of C 60 dimers. For larger aggregates, they form NFE bands of superatomic quantum structures and solids.The overlap of the diffuse SAMO wavefunctions in van der Waals solids provides a different paradigm for band formation than the valence or conduction bands formed by interaction of the more tightly bound, directional highest occupied molecular orbitals (HOMOs) or the lowest unoccupied molecular orbitals (LUMOs). Therefore, SAMO wavefunctions provide insights into the design of molecular materials with potentially superior properties for electronics.Physicists and chemists have thought of fullerenes as atom-like building blocks of electronic materials, and superatom properties have been attributed to other elemental gas-phase clusters based on their size-dependent electronic structure and reactivity. Only in the case of fullerenes, however, do the superatom properties survive as delocalized electronic bands even in the condensed phase. We emphasize, however, that the superatom states and their bands are usually unoccupied and therefore do not contribute to intermolecular bonding. Instead, their significance lies in the electronic properties they confer when electrons are introduced, such as when they are excited optically or probed by the atomically sharp tip of a scanning tunneling microscope.We describe the IP states of graphene as the primary manifestation of the universal polarization response of a molecular sheet and how these states in turn define the NFE properties of materials derived from graphene, such as graphite, fullerenes, and nanotubes. Through low-temperature scanning tunneling microscopy (LT-STM), time-resolved two-photon photoemission spectroscopy (TR-2PP), and density functional theory (DFT), we describe the real and reciprocal space electronic properties of SAMOs for single C60 molecules and their self-assembled 1D and 2D quantum structures on single-crystal metal surfaces. © 2011 American Chemical Society.

Wu Y.,Anhui University of Science and Technology | Wu S.,Max Planck Institute for Polymer Research | Zou G.,Anhui University of Science and Technology | Zhang Q.,Anhui University of Science and Technology
Soft Matter | Year: 2011

By introducing methanol as a co-solvent into cyclopentanone, solvent effects on structure, photoresponse and speed of gelation of a dicholesterol-linked azobenzene organogel DCAZO2 have been investigated. Optical microscopy (OM) and scanning electron microscopy (SEM) images reveal that the gel fibers form macroscopic aggregates by adding methanol. Minimum gelation concentration (MGC) of the gels decreases with increasing methanol content, while the gel-to-sol transition temperature (T gel) decreases firstly and increases afterwards. For photoisomerization (corresponding to gel-sol transition), the first stage rate constant k g1 of the gels decreases with increasing methanol content. The photoisomerization process of the gel with 5% methanol is different from the other five samples, whose first stage rate constant k g1 is greater than its second stage rate constant k g2. By increasing methanol content from 0% to 30%, gelation time (corresponding to sol-gel transition) of both heated gel and UV-visible light irradiated gel decreases from 7 h to 5 min and 6 h to 0 min (before visible light irradiation is accomplished), respectively. Solubility parameters and Teas plots of the gelator and mixed solvents are systematically calculated to estimate the gelator-solvent interaction. It is found that gelation requires that the gelator-solvent interaction be neither too strong nor too weak, otherwise solution or precipitate are formed. © 2011 The Royal Society of Chemistry.

Shu F.-J.,Shangqiu Normal University | Zou C.-L.,Anhui University of Science and Technology | Sun F.-W.,Anhui University of Science and Technology
Optics Letters | Year: 2012

In this Letter, we report on a perpendicular coupler (PC) for whispering-gallery resonators; it is a near field waveguide optimized for high coupling efficiency. The PC provides highly efficient tunneling coupling between the waveguide and microresonator without the need of a phase matching condition, and saves space for integration components. Compared to the Lorentz-shape in the transmission spectrum of the parallel coupler, the reflection spectrum of the PC shows an asymmetric Fano-shape near resonance. Furthermore, we demonstrate that the collection efficiency can be enhanced by near field scatterers, with a maximal efficiency of about 75%. Our simulations show that the PC is not sensitive to most parameters (including the refractive index of the waveguide), which makes the PC optimal for the application of whispering-gallery modes. © 2012 Optical Society of America.

Mao T.,Anhui University of Science and Technology | Ng K.W.,University of Hong Kong
Extremes | Year: 2015

Let X1, … , Xn be independent nonnegative random variables with respective survival functions F¯1,…,F¯, and let Θ1, … , Θn be (not necessarily independent) nonnegative random variables, independent of X1, … , Xn, satisfying certain moment conditions. This paper consists of two parts. In the first part, we investigate second-order expansions of (Formula presented.) as t→∞ under the assumption that the F¯i are of second-order regular variation (2RV) with the same first-order index but with different second-order indexes. In the second part, under the assumption that the F¯1=⋯=F¯n have 2RV tails, second-order expansions of tail probabilities of the randomly weighted sum (Formula presented.) are studied. The closure property of 2RV under randomly weighted sum is also discussed. The main results in this paper generalize and strengthen several known results in the literature. © 2015, Springer Science+Business Media New York.

Wu F.,Anhui University of Science and Technology | Guo G.-C.,Anhui University of Science and Technology | Zhang W.,Renmin University of China | Yi W.,Anhui University of Science and Technology
Physical Review Letters | Year: 2013

We study the phase diagram of a two-dimensional ultracold Fermi gas with the synthetic spin-orbit coupling (SOC) that has recently been realized at the National Institute of Standards and Technology (NIST). Because of the coexistence of anisotropic SOC and effective Zeeman fields in the NIST scheme, the system shows a rich structure of phase separation involving exotic gapless superfluid states and Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing states with different center-of-mass momenta. In particular, we characterize the stability region of FFLO states and demonstrate their unique features under SOC. We then show that the effective transverse Zeeman field in the NIST scheme can qualitatively change the landscape of the thermodynamic potential which leads to intriguing effects such as the disappearance of pairing instability, the competition between different FFLO states, and the stabilization of a fully gapped FFLO state. These interesting features may be probed, for example, by measuring the in situ density profiles or by the momentum-resolved radio-frequency spectroscopy. © 2013 American Physical Society.

Wu C.,Anhui University of Science and Technology | Lu X.,Anhui University of Science and Technology | Peng L.,University of Texas at Austin | Xu K.,Anhui University of Science and Technology | And 4 more authors.
Nature Communications | Year: 2013

Two-dimensional materials have been an ideal material platform for constructing flexible ultrathin-film supercapacitors, offering great advantages of flexibility, ultra-thinness and even transparency. Exploring new two-dimensional pseudocapacitive materials with high electrochemical activity is needed to achieve flexible ultrathin-film supercapacitors with higher energy densities. Here we report an inorganic graphene analogue, α 1 -vanadyl phosphate ultrathin nanosheets with less than six atomic layers, as a promising material to construct a flexible ultrathin-film pseudocapacitor in all-solid-state. The material exhibits a high potential plateau of ∼ 1.0 V in aqueous solutions, approaching the electrochemical potential window of water (1.23 V). The as-established flexible supercapacitor achieves a high redox potential (1.0 V) and a high areal capacitance of 8,360.5 μF cm-2, leading to a high energy density of 1.7 mWh cm-2 and a power density of 5.2 mW cm-2. © 2013 Macmillan Publishers Limited. All rights reserved.

Xie J.,Anhui University of Science and Technology | Zhang H.,Anhui University of Science and Technology | Li S.,Anhui University of Science and Technology | Wang R.,Anhui University of Science and Technology | And 5 more authors.

Defect-rich MoS2 ultrathin nanosheets are synthesized on a gram scale for electrocatalytic hydrogen evolution. The novel defect-rich structure introduces additional active edge sites into the MoS2 ultrathin nanosheets, which significantly improves their electrocatalytic performance. Low onset overpotential and small Tafel slope, along with large cathodic current density and excellent durability, are all achieved for the novel hydrogen-evolution-reaction electrocatalyst. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Huang W.,CAS Xishuangbanna Tropical Botanical Garden | Huang W.,Anhui University of Science and Technology | Zhang S.-B.,CAS Xishuangbanna Tropical Botanical Garden | Cao K.-F.,CAS Xishuangbanna Tropical Botanical Garden
Plant and Cell Physiology | Year: 2011

Our previous study indicated that PSII is more sensitive to chilling and light stress than PSI in tropical trees, and Erythrophleum guineense is more sensitive to chilling stress than Dalbergia odorifera and Khaya ivorensis, but the underlying physiological mechanisms are unclear. Although recent studies have reported that cyclic electron flow (CEF) plays an important role in photoprotection, the role of CEF in protecting PSI and PSII of tropical tree species remains unclear. We investigated the effect of temporal chilling temperature on energy distribution in PSII, the redox state of P700 and CEF in the above-mentioned tropical evergreen tree species grown in an open field. Our results indicated that the overclosure of PSII reaction centers at chilling temperature led to excess excitation pressure in PSII. At the temporal chilling temperature under low light, PSI acceptor side limitation [Y(NA)] was lower than those at 25°C for all species. Although the effective quantum yield of CEF [Y(CEF)] was not significantly stimulated in E. guineense and K. ivorensis under temporal chilling at low light levels, the ratio of Y(CEF) to the effective quantum yield of PSII [Y(II)] significantly increased. Under chilling conditions Y(CEF)/Y(II) was stimulated much more in K. ivorensis and D. odorifera compared with that in the chilling-sensitive E. guineense. These results suggested that stimulation of Y(CEF)/Y(II) plays an important role in protecting PSI and PSII from photoinhibition caused by chilling stress. © 2011 The Author.

Ye F.,Oak Ridge National Laboratory | Chi S.,Oak Ridge National Laboratory | Bao W.,Renmin University of China | Wang X.F.,Anhui University of Science and Technology | And 5 more authors.
Physical Review Letters | Year: 2011

Single-crystal neutron diffraction studies on superconductors A 2Fe4Se5, where A=Rb, Cs, (Tl, Rb), and (Tl, K) (Tc∼30K), uncover the same Fe vacancy ordered crystal structure and the same block antiferromagnetic order as in K2Fe 4Se5. The Fe order-disorder transition occurs at T S=500-578K, and the antiferromagnetic transition at T N=471-559K with an ordered magnetic moment ∼3.3μB/ Fe at 10 K. Thus, all recently discovered A intercalated iron selenide superconductors share the common crystalline and magnetic structure, which are very different from previous families of Fe-based superconductors, and constitute a distinct new 245 family. © 2011 American Physical Society.

Xu Y.,Anhui University of Science and Technology | Shu C.-W.,Brown University
Communications in Computational Physics | Year: 2010

Discontinuous Galerkin (DG) methods are a class of finite element methods using discontinuous basis functions, which are usually chosen as piecewise polynomials. Since the basis functions can be discontinuous, these methods have the flexibility which is not shared by typical finite element methods, such as the allowance of arbitrary triangulation with hanging nodes, less restriction in changing the polynomial degrees in each element independent of that in the neighbors (p adaptivity), and local data structure and the resulting high parallel efficiency. In this paper,we give a general review of the local DG (LDG) methods for solving high-order time-dependent partial differential equations (PDEs). The important ingredient of the design of LDG schemes, namely the adequate choice of numerical fluxes, is highlighted. Some of the applications of the LDG methods for high-order time-dependent PDEs are also be discussed. © 2010 Global-Science Press.

Sun Y.,Anhui University of Science and Technology | Lei F.,Anhui University of Science and Technology | Gao S.,Anhui University of Science and Technology | Pan B.,Anhui University of Science and Technology | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

The thinner the better: SnO2 sheets that are five atomic layers thick are an efficient catalyst for the oxidation of CO (see picture). These sheets, which have 40 % surface atom occupancy and are fabricated by a scalable ethylenediamine-assisted pathway, show remarkably improved catalytic performances compared to other SnO2 species, with the apparent activation energy lowered to 59.2 kJ mol-1 and the full-conversion-temperature lowered to 250 °C. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yi W.,Anhui University of Science and Technology | Zhang W.,Renmin University of China
Physical Review Letters | Year: 2012

We show that spin-orbit coupling (SOC) gives rise to pairing instability in a highly polarized two-dimensional Fermi gas for an arbitrary interaction strength. The pairing instability can lead to a Fulde-Ferrell-Larkin- Ovchinnikov-like molecular state, which undergoes a first-order transition into a pairing state with zero center-of-mass momentum as the parameters are tuned. These pairing states are metastable against a polaron state dressed by particle-hole fluctuations for small SOC. At large SOC, a polaron-molecule transition exists, which suggests a phase transition between the topological superfluid state and the normal state for a highly polarized Fermi gas in the thermodynamic limit. As polarization in a Fermi gas with SOC is induced by the effective Zeeman field, we also discuss the influences of the effective Zeeman field on the ground state of the system. Our findings may be tested directly in future experiments. © 2012 American Physical Society.

Culcer D.,Anhui University of Science and Technology | Culcer D.,University of New South Wales | Zimmerman N.M.,U.S. National Institute of Standards and Technology
Applied Physics Letters | Year: 2013

We study the effect of charge and spin noise on singlet-triplet qubits in Si quantum dots. We set up a theoretical framework aimed at enabling experiment to efficiently identify the most deleterious defects, and complement it with the knowledge of defects gained in decades of industrial and academic work. We relate the dephasing rates Γ φ due to various classes of defects to experimentally measurable parameters, such as charge dipole moment, spin dipole moment, and fluctuator switching times. We find that charge fluctuators are more efficient in causing dephasing than spin fluctuators. © 2013 AIP Publishing LLC.

Zhou J.,Anhui University of Science and Technology | Zhang W.,Renmin University of China | Yi W.,Anhui University of Science and Technology
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2011

We study the stability region of the topological superfluid phase in a trapped two-dimensional polarized Fermi gas with spin-orbit coupling and across a BCS-BEC crossover. Due to the competition between polarization, pairing interaction, and spin-orbit coupling, the Fermi gas typically phase-separates in the trap. Employing a mean-field approach that guarantees the ground-state solution, we systematically study the structure of the phase separation and investigate in detail the optimal parameter region for the preparation of the topologically nontrivial superfluid phase. We then calculate the momentum space density distribution of the topological superfluid state and demonstrate that the existence of the phase leaves a unique signature in the trap integrated momentum space density distribution which can survive the time-of-flight imaging process. © 2011 American Physical Society.

Yu S.Y.,Guangzhou University | Qi R.,Guangzhou University | Zhao H.,Anhui University of Science and Technology
Molecular Biology Reports | Year: 2013

Podocyte impairment is a key pathogenic even in the initiation and development of glomerular diseases associated with proteinuria. The type 2 diabetic patients is characterized by progressive increases in albuminuria which are associated with the development of characteristic histopathological features. Losartan had a benefit in decreasing albuminuria in type 2 diabetic patients,suggesting that losartan may have another effect other than blockade of the traditional renin-angiotensin system (RAS). However, the mechanism has remained undetermined. Glucose transporter 1 (GLUT1) is the predominant basal glucose transporter. In the kidney, GLUT1 was overexpressed predominantly in glomerular mesangial cells and in small vessels, rather than in podocytes. The increased glomerular GLUT1 mimicked diabetes-induced glomerular GLUT1 expression. In this study, we hypothesized that increased GLUT1 expression induced by angiotensinII (AngII) contributes to the progression of podocytes injury, losartan can block the effect of AngII and protect podocytes via stabilizing the expression of GLUT1, our results strongly suggest that losartan has a direct and protective effect on podocytes. This represents a novel mechanism by which losartan may protect podocyte from apoptotic death and improve podocyte function via stabilizing the expression of GLUT1. This finding underlines the crucial role of GLUT1 in the pathogenesis of podocyte injury and proteinuria. © 2013 Springer Science+Business Media Dordrecht.

Hu B.,Anhui University of Science and Technology | Wang K.,Anhui University of Science and Technology | Wu L.,Anhui University of Science and Technology | Yu S.-H.,Anhui University of Science and Technology | And 2 more authors.

Energy shortage, environmental crisis, and developing customer demands have driven people to find facile, low-cost, environmentally friendly, and nontoxic routes to produce novel functional materials that can be commercialized in the near future. Amongst various techniques, the hydrothermal carbonization (HTC) process of biomass (either of isolated carbohydrates or crude plants) is a promising candidate for the synthesis of novel carbon-based materials with a wide variety of potential applications. In this Review, we will discuss various synthetic routes towards such novel carbon-based materials or composites via the HTC process of biomass. Furthermore, factors that influence the carbonization process will be analyzed and the special chemical/ physical properties of the final products will be discussed. Despite the lack of a clear mechanism, these novel carbonaceous materials have already shown promising applications in many fields such as carbon fixation, water purification, fuel cell catalysis, energy storage, CO2 sequestration, bioimaging, drug delivery, and gas sensors. Some of the most promising examples will also be discussed here, demonstrating that the HTC process can rationally design a rich family of carbonaceous and hybrid functional carbon materials with important applications in a sustainable fashion. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.

Xu Y.,Anhui University of Science and Technology | Shu C.-W.,Brown University
Communications in Computational Physics | Year: 2011

In this paper, we develop, analyze and test local discontinuous Galerkin (LDG) methods for solving the Degasperis-Procesi equation which contains nonlinear high order derivatives, and possibly discontinuous or sharp transition solutions. The LDG method has the flexibility for arbitrary h and p adaptivity. We prove the L2 stability for general solutions. The proof of the total variation stability of the schemes for the piecewise constant P 0 case is also given. The numerical simulation results for different types of solutions of the nonlinear Degasperis-Procesi equation are provided to illustrate the accuracy and capability of the LDG method. © 2011 Global-Science Press.

Scott M.A.,University of Texas at Austin | Li X.,Anhui University of Science and Technology | Sederberg T.W.,Brigham Young University | Hughes T.J.R.,University of Texas at Austin
Computer Methods in Applied Mechanics and Engineering | Year: 2012

We develop a local refinement algorithm for analysis-suitable T-splines which does not produce excessive propagation of control points. We then demonstrate its use as an adaptive framework for isogeometric analysis. Analysis-suitable T-splines are a class of T-splines which are linearly independent and form a partition of unity. These properties, coupled with local refinement, make this class of T-splines appealing as a basis for isogeometric analysis. © 2011 Elsevier B.V.

Zhang W.,Renmin University of China | Yi W.,Anhui University of Science and Technology
Nature Communications | Year: 2013

Pairing in an attractively interacting two-component Fermi gas in the absence of time-reversal symmetry or inversion symmetry may give rise to exotic superfluid states. Notable examples range from the Fulde-Ferrell-Larkin-Ovchinnikov state with a finite centre-of-mass momentum in a polarized Fermi gas to the topological superfluid (TSF) state in a two-dimensional (2D) Fermi gas under Rashba spin-orbit coupling and an out-of-plane Zeeman field. Here we show that a TSF state with a single-component nonzero centre-of-mass momentum, called a topological Fulde-Ferrell (tFF) state, can be stabilized in a 2D Fermi gas with Rashba spin-orbit coupling and both in-plane and out-of-plane Zeeman fields. The tFF state features a non-trivial Berry phase, along with unique properties that may be detected using existing experimental techniques. © 2013 Macmillan Publishers Limited. All rights reserved.

Liu X.-Q.,University of Chinese Academy of Sciences | Song W.-J.,University of Chinese Academy of Sciences | Sun T.-M.,Anhui University of Science and Technology | Zhang P.-Z.,Suzhou GenePharma Co. | Wang J.,University of Chinese Academy of Sciences
Molecular Pharmaceutics | Year: 2011

MiRNAs are viable therapeutic targets for cancer therapy, but the targeted delivery of miRNA or its anti-miRNA antisense oligonucleotides (AMOs) remains a challenge. We report here a PEGylated LPH (liposome-polycation-hyaluronic acid) nanoparticle formulation modified with cyclic RGD peptide (cRGD) for specific and efficient delivery of AMO into endothelial cells, targeting αvβ3 integrin present on the tumor neovasculature. The nanoparticles effectively delivered anti-miR-296 AMO to the cytoplasm and downregulated the target miRNA in human umbilical vein endothelial cells (HUVECs), which further efficiently suppressed blood tube formulation and endothelial cell migration, owing to significant upregulation of hepatocyte growth factor-regulated tyrosine kinase substrate (HGS), whereas nanoparticles without cRGD modification showed only little AMO uptake and miRNA silencing activity. In vivo assessment of angiogenesis using Matrigel plug assay also demonstrated that cRGD modified LPH nanoparticles have potential for antiangiogenesis in miRNA therapeutics. With the delivery of anti-miR-296 AMO by targeted nanoparticles, significant decrease in microvessel formulation within Matrigel was achieved through suppressing the invasion of CD31-positive cells into Matrigel and prompting HGS expression in angiogenic endothelial cells. © 2011 American Chemical Society.

Tian Y.-J.,Anhui University of Science and Technology | Meijer E.W.,TU Eindhoven | Wang F.,Anhui University of Science and Technology | Wang F.,TU Eindhoven
Chemical Communications | Year: 2013

Rod-like platinum(ii) acetylide complexes have been demonstrated to form one-dimensional helical supramolecular polymers by the cooperative growth mechanism, leading to supramolecular gels by bundling single fibrils into entangled networks. © 2013 The Royal Society of Chemistry.

Bai J.,Shandong University | Li X.,Shandong University | Liu G.,Shandong University | Liu G.,Shandong Normal University | And 4 more authors.
Advanced Functional Materials | Year: 2014

A facile two-step strategy involving a polyol method and subsequent thermal annealing treatment is successfully developed for the large-scale preparation of ZnCo2O4 various hierarchical micro/nanostructures (twin mcrospheres and microcubes) without surfactant assistance. To the best of our knowledge, this is the first report on the synthesis of ZnCo2O 4 mesoporous twin microspheres and microcubes. More significantly, based on the effect of the reaction time on the morphology evolution of the precursor, a brand-new crystal growth mechanism, multistep splitting then in situ dissolution recrystallization accompanied by morphology and phase change, is first proposed to understand the formation of the 3D twin microshperes, providing new research opportunity for investigating the formation of novel micro/nanostructures. When evaluated as anode materials for lithium-ion batteries (LIBs), ZnCo2O4 hierarchical microstructures exhibit superior capacity retention, excellent cycling stability at the 5 A g-1 rate for 2000 cycles. Surprisingly, the ZnCo2O 4 twin microspheres show an exceptionally high rate capability up to the 10 A g-1 rate. It should be noted that such super-high rate performance and cycling stability at such high charge/discharge rates are significantly higher than most work previously reported on ZnCo 2O4 micro/nanostructures and ZnCo2O 4-based heterostructures. The ZnCo2O4 3D hierarchical micro/nanostructures demonstrate the great potential as negative electrode materials for high-performance LIBs. 3D hierarchical ZnCo 2O4 twin spheres are prepared via a convenient polyol process and subsequent thermal annealing. A multistep splitting in situ dissolution recrystallization originating from 1D nanorods is first proposed to understand the formation of the 3D nanoarchitectures. Lithium-ion batteries prepared with the 3D materials display remarkable performance in energy storage. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Song W.-J.,Anhui University of Science and Technology | Du J.-Z.,Anhui University of Science and Technology | Sun T.-M.,Anhui University of Science and Technology | Zhang P.-Z.,Suzhou GenePharma Co. | Wang J.,Anhui University of Science and Technology
Small | Year: 2010

An efficient and safe delivery system for small interfering RNA (siRNA) is required for clinical application of RNA interfering therapeutics. Polyethyleneimine (PEI)-capped gold nanoparticles (AuNPs) are successfully manufactured using PEI as the reductant and stabilizer, which bind siRNA at an appropriate weight ratio by electrostatic interaction and result in well-dispersed nanoparticles with uniform structure and narrow size distribution. With siRNA binding, PEI-capped AuNPs induce more significant and enhanced reduction in targeted green fluorescent protein expression in MDA-MB-435s cells, though more internalized PEI/siRNA complexes in cells are evidenced by confocal laser scanning microscopy observation and fluorescence-activated cell sorting analyses. PEI-capped AuNPs/siRNA targeting endogenous cell-cycle kinase, an oncogene polo-like kinase 1 (PLK1), display significant gene expression knockdown and induce enhanced cell apoptosis, whereas it is not obvious when the cells are treated with PLK1 siRNA using PEI as the carrier. Without exhibiting cellular toxicity, PEI-capped AuNPs appear to be suitable as a potential carrier for intracellular siRNA delivery. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

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

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

Qian S.,University of Electronic Science and Technology of China | Sheng Y.,Anhui University of Science and Technology
Annals of Biomedical Engineering | Year: 2011

Photogrammetry has become an effective method for the determination of electroencephalography (EEG) electrode positions in three dimensions (3D). Capturing multi-angle images of the electrodes on the head is a fundamental objective in the design of photogrammetry system for EEG localization. Methods in previous studies are all based on the use of either a rotating camera or multiple cameras, which are time-consuming or not cost-effective. This study aims to present a novel photogrammetry system that can realize simultaneous acquisition of multi-angle head images in a single camera position. Aligning two planar mirrors with the angle of 51.4°, seven views of the head with 25 electrodes are captured simultaneously by the digital camera placed in front of them. A complete set of algorithms for electrode recognition, matching, and 3D reconstruction is developed. It is found that the elapsed time of the whole localization procedure is about 3 min, and camera calibration computation takes about 1 min, after the measurement of calibration points. The positioning accuracy with the maximum error of 1.19 mm is acceptable. Experimental results demonstrate that the proposed system provides a fast and cost-effective method for the EEG positioning. © 2011 Biomedical Engineering Society.

Huang L.,Shanxi University | Meng Z.,Shanxi University | Wang P.,Shanxi University | Peng P.,Shanxi University | And 6 more authors.
Nature Physics | Year: 2016

Spin-orbit coupling (SOC) is central to many physical phenomena, including fine structures of atomic spectra and topological phases in ultracold atoms. Whereas, in general, SOC is fixed in a system, laser-atom interaction provides a means to create and control synthetic SOC in ultracold atoms. Despite significant experimental progress in this area, two-dimensional (2D) synthetic SOC, which is crucial for exploring two- and three-dimensional topological phases, is lacking. Here, we report the experimental realization of 2D SOC in ultracold 40 K Fermi gases using three lasers, each of which dresses one atomic hyperfine spin state. Through spin-injection radiofrequency (rf) spectroscopy, we probe the spin-resolved energy dispersions of the dressed atoms, and observe a highly controllable Dirac point created by the 2D SOC. These results constitute a step towards the realization of new topological states of matter. © 2016 Macmillan Publishers Limited.

Sojka D.K.,University of Washington | Tian Z.,Anhui University of Science and Technology | Tian Z.,Hefei National Laboratory for Physical science at Microscale | Yokoyama W.M.,University of Washington | Yokoyama W.M.,Howard Hughes Medical Institute
Seminars in Immunology | Year: 2014

Conventional NK cells are well characterized in the mouse spleen and circulate in the blood. Less well described are NK cells found in organs such as the liver, thymus, and uterus. Recently we identified a tissue-resident NK (trNK) cell population in the liver, suggesting a potential diversity of trNK cells in other organs. In this review we compare and contrast the similarities and differences among the subpopulations of NK and innate lymphoid cells to the trNK cells in the liver. © 2014 Elsevier Ltd.

Ji F.,Anhui University of Science and Technology | Chen X.,Anhui University of Science and Technology | Lu W.,Anhui University of Science and Technology | Rodrigues J.J.P.C.,University of Beira Interior | Zhu Z.,Anhui University of Science and Technology
Journal of Lightwave Technology | Year: 2014

We investigate dynamic pre-configured-cycle (p-cycle) protection design for spectrum-sliced elastic optical networks (EONs). Several novel algorithms are proposed to use the spectrum planning of working and backup resources. We first combine the protected working capacity envelope (PWCE) p-cycle design with spectrum planning, and design an algorithm that can achieve dynamic p-cycle design in EONs. Then, to resolve the coverage issue of the PWCE-p-cycles, we consider dynamic p-cycle design with Hamiltonian cycles and propose to use topology partition for reducing the lengths of backup paths. Simulation results show that our proposed algorithms achieve lower blocking probability than the shared path-protection (SPP) algorithm, while the average length of backup paths per request can be controlled well. To the best of our knowledge, this is the first attempt to address dynamic p-cycle protection design with spectrum planning for EONs. © 2014 IEEE.

Li C.,Ningbo University | Li C.,Anhui University of Science and Technology | He J.,Ningbo University
Reviews in Mathematical Physics | Year: 2012

In this paper, we firstly give the definition of dispersionless bigraded Toda hierarchy (dBTH) and introduce some Sato theory on dBTH. Then we define OrlovSchulman's $\mathcal{M}-L$, $\mathcal{M}-R$ operator and give the additional Block symmetry of dBTH. Meanwhile we give tau function of dBTH and some related dispersionless bilinear equations. © 2012 World Scientific Publishing Company.

Xie K.,University of St. Andrews | Xie K.,Anhui University of Science and Technology | Zhang Y.,University of St. Andrews | Meng G.,Anhui University of Science and Technology | Irvine J.T.S.,University of St. Andrews
Journal of Materials Chemistry | Year: 2011

Synthetic hydrocarbon fuels from CO2/H2O are proposed as alternatives to hydrogen as an energy carrier to enable a carbon neutral energy cycle, given their inherent advantages of high H/C ratio and convenience of storage and transportation. Here we demonstrate the successful electrochemical reduction of CO2 into CO and CH4 in a proton conducting solid oxide electrolyser based on BaCe0.5Zr 0.3Y0.16Zn0.04O3 - δ (BCZYZ) electrolyte and a composite iron/iron oxide cathode. The production of CH 4 and CO reaches 0.07 and 3.25 ml min-1 cm-2, respectively, with 1.5 A cm-2 at 614°C. The overall CO 2 conversion rate in the electrochemical reduction process is 65%. © The Royal Society of Chemistry.

Liu H.,Anhui University of Science and Technology | Shen R.,Anhui University of Science and Technology | Song K.,Anhui University of Science and Technology | Li Y.,State Key Laboratory of Polymer Physics and Chemistry
ChemPhysChem | Year: 2012

Reduction of bare carbon dots (CDs) in aqueous NaBH4 solution is a facile and effective approach to enhance their fluorescence without any surface coverage. CDs are treated with dilute aqueous NaBH4 solutions, enhancing their quantum yields (QYs) successfully from 1.6 % to 16 % which is comparable to semiconductive QDs in aqueous environments. If pristine CDs are treated hydrothermally prior to reduction by NaBH4, QYs reach 40.5 %. This value is among the highest QYs reported for bare CDs in the literature. The approach to enhance fluorescence through chemical reduction is generally applicable to other kinds of CDs synthesized by various methods. Alteration of the chemical structure of the CDs by NaBH4-reduction is analyzed by 13C NMR, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy, which demonstrate that the carbonyl group content is decreased after NaBH4-reduction, whereas the number of sp 3-type carbon defects is increased. The valence-band maxima (VBM) near the surface related to the surface energy bands of the CDs are estimated by XPS. VBM data show a semiconducting layer on the surface of the CDs, and the VBM of the CDs decrease with increasing NaBH4-reduction time. The layered graphite structures in the cores of the CDs are clearly observed by transmission electron microscopy (TEM). CDs could perhaps be regarded as semiconductive surface defect layers formed by chemical erosion over conductive graphite cores. Chemical reduction by NaBH4 changes the surface-energy bands of the CDs, thus, enhances their fluorescence. The fluorescence properties of aqueous NaBH4-reduced CDs are also studied for possible biological applications. Reduce to improve: Reduction by aqueous NaBH4 is an efficient way to enhance the fluorescence of aqueous carbon dots (CDs). We found that the structure of CDs can be regarded as semiconductive surface layers over conductive graphite cores (see picture). Chemical reduction increases the number of surface defects leading to conjugation of the defect areas. Thus, the surface is changed to improve fluorescence properties. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wu X.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Dai J.,University of Nebraska - Lincoln | Zhao Y.,University of Nebraska - Lincoln | Zhuo Z.,CAS Hefei Key Laboratory of Materials for Energy Conversion | And 3 more authors.
ACS Nano | Year: 2012

Boron, a nearest-neighbor of carbon, is possibly the second element that can possess free-standing flat monolayer structures, evidenced by recent successful synthesis of single-walled and multiwalled boron nanotubes (MWBNTs). From an extensive structural search using the first-principles particle-swarm optimization (PSO) global algorithm, two boron monolayers (α 1- and β 1-sheet) are predicted to be the most stable α- and β-types of boron sheets, respectively. Both boron sheets possess greater cohesive energies than the state-of-the-art two-dimensional boron structures (by more than 60 meV/atom based on density functional theory calculation using PBE0 hybrid functional), that is, the α-sheet previously predicted by Tang and Ismail-Beigi and the g 1/8- and g 2/15-sheets (both belonging to the β-type) recently reported by Yakobson and co-workers. Moreover, the PBE0 calculation predicts that the α-sheet is a semiconductor, while the α 1-, β 1-, g 1/8-, and g 2/15-sheets are all metals. When two α 1 monolayers are stacked on top each other, the bilayer α 1-sheet remains flat with an optimal interlayer distance of ∼3.62 Å, which is close to the measured interlayer distance (∼3.2 Å) in MWBNTs. © 2012 American Chemical Society.

Bai S.,Anhui University of Science and Technology | Wang C.,Anhui University of Science and Technology | Deng M.,Anhui University of Science and Technology | Deng M.,Guizhou Normal College | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2014

Surface charge state plays an important role in tuning the catalytic performance of nanocrystals in various reactions. Herein, we report a synthetic approach to unique Pt-Pd-graphene stack structures with controllable Pt shell thickness. These unique hybrid structures allow us to correlate the Pt thickness with performance in the hydrogen-evolution reaction (HER). The HER activity increases with a decrease in the Pt thickness, which is well explained by surface polarization mechanism as suggested by first-principles simulations. In this hybrid system, the difference in work functions of Pt and Pd results in surface polarization on the Pt surface, tuning its charge state for hydrogen reduction. Meanwhile, the supporting graphene provides two-dimensional channels for efficient charge transport, improving the HER activities. This work opens up possibilities of reducing Pt usage while achieving high HER performance. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xie K.,University of St. Andrews | Xie K.,Anhui University of Science and Technology | Zhang Y.,University of St. Andrews | Meng G.,Anhui University of Science and Technology | Irvine J.T.S.,University of St. Andrews
Energy and Environmental Science | Year: 2011

Synthetic fuels produced from CO2/H2O are an attractive alternative energy carrier. Here we demonstrate a novel strategy to electrochemically convert CO2/H2O into hydrocarbon in a single step in an oxygen-ion conducting solid oxide electrolyser. Methane was directly synthesized in an efficient electrolyser with configuration of (anode) (La0.8Sr0.2)0.95MnO3-δ/YSZ/ La0.2Sr0.8TiO3+δ (cathode) by combining coelectrolysis of CO2/H2O and in situ Fischer-Tropsch-type synthesis. We demonstrate a high Faradaic yield of CO/H2 and lower methane yield, which shows that the limit on conversion efficiency comes from the heterogeneous catalysis process. Electrochemical results also show that the electrochemical reduction of La0.2Sr0.8TiO 3+δ cathode is the main process at low electrical voltages while the coelectrolysis is the main process at high voltages. © 2011 The Royal Society of Chemistry.

He X.,China Academy of Safety Science and Technology | Song L.,Anhui University of Science and Technology
Safety Science | Year: 2012

In general, contexts of coal mining safety involve technology, administration and socioeconomic environment as well. This paper presents statistical analysis of China coal mine accidents in recent years and analyzes the reasons causing coal mining high risk from technical and socioeconomic viewpoints. Social and economic reform has been unleashing social, economical factors that are driving a fundamental transformation of new workplace safety problems and making China coal mining safety take on Chinese features. Compared with major state-owned and local state-owned coalmines, township and village coalmines are most dangerous coal mines with highest occupational risks. The incidence and death toll of ceiling accidents are higher than those of accidents such as gas, machinery, electricity, transportation, flood, and fire. New organizational risks appeared with rapid development of state-owned coal mines' reorganization. Low skilled labors restrict both technical renovation and safety management. The Government has adopted a systematic arrangement to improve coal mining safety such as closing the township and village coalmines that cannot meet the standard of safety, reinforcing the supervision over coal mining safety, strengthening technological renovation and enhancing work safety input. © 2011 Elsevier Ltd.

Li X.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Wu X.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Wu X.,Anhui University of Science and Technology | Zeng X.C.,University of Nebraska - Lincoln | Yang J.,Anhui University of Science and Technology
ACS Nano | Year: 2012

We perform a comprehensive study of the effects of line defects on electronic and magnetic properties of monolayer boron-nitride (BN) sheets, nanoribbons, and single-walled BN nanotubes using first-principles calculations and Born-Oppenheimer quantum molecular dynamic simulation. Although line defects divide the BN sheet (or nanotube) into domains, we show that certain line defects can lead to tailor-made edges on BN sheets (or imperfect nanotube) that can significantly reduce the band gap of the BN sheet or nanotube. In particular, we find that the line-defect-embedded zigzag BN nanoribbons (LD-zBNNRs) with chemically homogeneous edges such as B- or N-terminated edges can be realized by introducing a B 2, N 2, or C 2 pentagon-octagon-pentagon (5-8-5) line defect or through the creation of the antisite line defect. The LD-zBNNRs with only B-terminated edges are predicted to be antiferromagnetic semiconductors at the ground state, whereas the LD-zBNNRs with only N-terminated edges are metallic with degenerated antiferromagnetic and ferromagnetic states. In addition, we find that the hydrogen-passivated LD-zBNNRs as well as line-defect-embedded BN sheets (and nanotubes) are nonmagnetic semiconductors with markedly reduced band gap. The band gap reduction is attributed to the line-defect-induced impurity states. Potential applications of line-defectembedded BN nanomaterials include nanoelectronic and spintronic devices. © 2012 American Chemical Society.

Liu N.,University of Nebraska - Lincoln | Ding Y.,University of Nebraska - Lincoln | Ding Y.,Anhui University of Science and Technology | Fromm M.,University of Nebraska - Lincoln | Avramova Z.,University of Nebraska - Lincoln
Nucleic Acids Research | Year: 2014

Plants that have experienced several exposures to dehydration stress show increased resistance to future exposures by producing faster and/or stronger reactions, while many dehydration stress responding genes in Arabidopsis thaliana super-induce their transcription as a 'memory' from the previous encounter. A previously unknown, rather unusual, memory response pattern is displayed by a subset of the dehydration stress response genes. Despite robustly responding to a first stress, these genes return to their initial, pre-stressed, transcript levels during the watered recovery; surprisingly, they do not respond further to subsequent stresses of similar magnitude and duration. This transcriptional behavior defines the 'revised-response' memory genes. Here, we investigate the molecular mechanisms regulating this transcription memory behavior. Potential roles of abscisic acid (ABA), of transcription factors (TFs) from the ABA signaling pathways (ABF2/3/4 and MYC2), and of histone modifications (H3K4me3 and H3K27me3) as factors in the revised-response transcription memory patterns are elucidated. We identify the TF MYC2 as the critical component for the memory behavior of a specific subset of MYC2-dependent genes. © The Author(s) 2014.

Freed K.F.,James Franck Institute | Wu C.,Chinese University of Hong Kong | Wu C.,Anhui University of Science and Technology
Macromolecules | Year: 2011

Using recently developed analytical Green's function/numerical inverse Laplace transform methods, we calculate the hydrodynamic drag and confinement forces on a linear Gaussian chain inside an interacting and impenetrable cylindrical tube in the free draining limit. Equating the two forces leads to an estimation of the critical (minimum) flow rate (q c) to drag the chain through the tube. The estimated q c is compared with our measured q c in theta solutions as well as with our previous scaling argument for a variety of experimental conditions (solvent quality and tube radius, R). Satisfactory agreement between the calculated and observed critical flow rates reveals that the previous description by de Gennes of a linear chain confined in a tube as a series of hard spheres (blobs) significantly underestimates the hydrodynamic drag force, such that the predicted q c for the hard sphere model is 10 2-10 3 times higher than observed. The calculations also confirm our previous scaling argument that q c decreases with increasing R, thus departing from the hard-sphere blob prediction that q c is independent of R. More importantly, the calculation describes how interactions with the tube walls affect chain confinement. © 2011 American Chemical Society.

Jiang R.,Chinese University of Hong Kong | Li B.,Anhui University of Science and Technology | Fang C.,Chinese University of Hong Kong | Wang J.,Chinese University of Hong Kong

Hybrid nanostructures composed of semiconductor and plasmonic metal components are receiving extensive attention. They display extraordinary optical characteristics that are derived from the simultaneous existence and close conjunction of localized surface plasmon resonance and semiconduction, as well as the synergistic interactions between the two components. They have been widely studied for photocatalysis, plasmon-enhanced spectroscopy, biotechnology, and solar cells. In this review, the developments in the field of (plasmonic metal)/semiconductor hybrid nanostructures are comprehensively described. The preparation of the hybrid nanostructures is first presented according to the semiconductor type, as well as the nanostructure morphology. The plasmonic properties and the enabled applications of the hybrid nanostructures are then elucidated. Lastly, possible future research in this burgeoning field is discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tafti F.F.,Université de Sherbrooke | Juneau-Fecteau A.,Université de Sherbrooke | Delage M-E.,Université de Sherbrooke | Rene De Cotret S.,Université de Sherbrooke | And 8 more authors.
Nature Physics | Year: 2013

Proximity to an antiferromagnetic phase suggests that pairing in iron-based superconductors is mediated by spin fluctuations1-4, but orbital fluctuations have also been invoked. The former typically favour a pairing state of extended s-wave symmetry with a gap that changes sign between electron and hole Fermi surfaces6-9 (s ±), whereas the latter yield a standard s-wave state without sign change5 (s ++). Here we show that applying pressure to KFe2As2 induces a sudden change in the critical temperature Tc, from an initial decrease with pressure to an increase above a critical pressure Pc. The smooth evolution of the resistivity and Hall coefficient through Pc rules out a change in the Fermi surface. We infer that there must be a change of pairing symmetry at P c. Below P c, there is compelling evidence for a d-wave state. Above P c, the high sensitivity to disorder rules out an s++ state. Given the near degeneracy of d-wave and s± states found theoretically, we propose an s ± state above Pc. A change from d-wave to s-wave would probably proceed through an intermediate s+id state that breaks time-reversal symmetry20-22. © 2013 Macmillan Publishers Limited. All rights reserved.

Liu Y.,Anhui University of Science and Technology | Wu X.,Anhui University of Science and Technology | Zhao Y.,University of Nebraska - Lincoln | Zeng X.C.,University of Nebraska - Lincoln | Yang J.,Anhui University of Science and Technology
Journal of Physical Chemistry C | Year: 2011

Motivated by successful fabrication of monolayer materials consisting of hybrid graphene and boron nitride domains (Ci, L.; et al. Nat. Mater. 2010, 9, 430-435), we report a first-principles study of hybrid graphene/boron nitride (C-BN) nanoribbons with dihydrogenated edge(s). The first-principles study suggests that hybrid C-BN nanoribbons can possess half-metallicity with a certain range of widths for the graphene and BN sections. In general, the hybrid C-BN nanoribbons, either in HC 1HB 2-(C2)m(BN)n or HC 2HB 2-(C2)m(BN) n form, can undergo the semiconductor-to-half-metal-to-metal transitions as the width of both graphene and BN nanoribbons increases. The calculated electronic structures of the hybrid C-BN nanoribbons suggest that dihydrogenation of the boron edge can induce localized edge states around the Fermi level, and the interaction among the localized edge states can lead to the semiconductor-to-half-metal-to-metal transitions. © 2011 American Chemical Society.

Lu P.,Nanjing University of Aeronautics and Astronautics | Lu P.,University of Nebraska - Lincoln | Wu X.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Wu X.,Anhui University of Science and Technology | And 2 more authors.
Physical Chemistry Chemical Physics | Year: 2012

We investigate the strain-dependent electronic and magnetic properties of two-dimensional (2D) monolayer and bilayer MoS 2, as well as 1D MoS 2 nanoribbons and nanotubes using first-principles calculations. For 2D monolayer MoS 2 subjected to isotropic or uniaxial tensile strain, the direct band gap of MoS 2 changes to an indirect gap that decreases monotonically with increasing strain; while under the compressive strain, the original direct band gap is enlarged first, followed by gap reduction when the strain is beyond -2%. The effect of isotropic strain is even stronger than that of uniaxial strain. For bilayer MoS 2 subjected to isotropic tensile strain, its indirect gap reduces monotonically to zero at strain about 6%; while under the isotropic compressive strain, its indirect gap increases first and then reduces and turns into direct gap when the strain is beyond -4%. For strained 1D metallic zigzag MoS 2 nanoribbons, the net magnetic moment increases slightly with axial strain from about -5% to 5%, but drops to zero when the compressive strain is beyond -5% or increases with a power law beyond 5%. For 1D armchair MoS 2 nanotubes, tensile or compressive axial strain reduces or enlarges the band gap linearly, and the gap can be fully closed for nanotubes with relatively small diameter or under large tensile strain. For zigzag MoS 2 nanotubes, the strain effect becomes nonlinear and the tensile strain can reduce the band gap, whereas compressive strain can initially enlarge the band gap and then decrease it. The strain induced change in projected orbitals energy of Mo and the coupling between the Mo atom d orbital and the S atom p orbital are analyzed to explain the strong strain effect on the band gap and magnetic properties. © 2012 the Owner Societies.

Dai J.,University of Nebraska - Lincoln | Wu X.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Yang J.,Anhui University of Science and Technology | Zeng X.C.,University of Nebraska - Lincoln | Zeng X.C.,Anhui University of Science and Technology
Journal of Physical Chemistry Letters | Year: 2014

We perform a global search of the most stable structures of 2D stoichiometric AlxC (x = 1/3, 1, 2, and 3) monolayer sheets. In the most stable 2D planar AlC network, every carbon atom is tetracoordinated. In addition to the structure of AlC, structures of the most stable Al2C and Al3C monolayer sheets are also predicted for the first time. AlC and Al2C monolayers are semiconducting, while Al3C monolayer is metallic. In particular, Al2C monolayer possesses a bandgap of 1.05 eV (based on HSE06 calculation), a value suitable for photovoltaic applications. Moreover, three Al2C/WSe2, Al2C/MoTe2, and AlC/ZnO van der Waals heterobilayers are investigated, and their power conversion efficiencies are estimated to be in the range of 12-18%. The near-perfect match in lattice constants between the Al2C monolayer and PdO (100) surface suggests strong likelihood of experimental realization of the Al2C monolayer on the PdO (100) substrate. © 2014 American Chemical Society.

Dai J.,University of Nebraska - Lincoln | Wu X.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Yang J.,Anhui University of Science and Technology | Zeng X.C.,University of Nebraska - Lincoln | Zeng X.C.,Anhui University of Science and Technology
Journal of Physical Chemistry Letters | Year: 2014

On the basis of a global structural search and first-principles calculations, we predict two types of porous boron-nitride (BN) networks that can be built up with zigzag BN nanoribbons (BNNRs). The BNNRs are either directly connected with puckered B (N) atoms at the edge (type I) or connected with sp3-bonded BN chains (type II). Besides mechanical stability, these materials are predicted to be thermally stable at 1000 K. The porous BN materials entail large surface areas, ranging from 2800 to 4800 m2/g. In particular, type-II BN material with relatively large pores is highly favorable for hydrogen storage because the computed hydrogen adsorption energy (-0.18 eV) is very close to the optimal adsorption energy (-0.15 eV) suggested for reversible hydrogen storage at room temperature. Moreover, the type-II materials are semiconductors with width-dependent direct bandgaps, rendering the type-II BN materials promising not only for hydrogen storage but also for optoelectronic and photonic applications. © 2014 American Chemical Society.

Ge H.,Chinese University of Hong Kong | Wu C.,Chinese University of Hong Kong | Wu C.,Anhui University of Science and Technology
Macromolecules | Year: 2010

A study was conducted to demonstrate the separation of linear and star chains by a nanopore. It was demonstrated that it was practically possible to separate linear and star chains by flushing a mixture of them through a nanopore with a properly chosen flow rate. Polystyrene (PS) linear and star chains were synthesized with different lengths by using divinylbenzene to couple living polystyl linear chains in solution. The prepared star chains were fractionated into a series of narrowly distribution star chains with different numbers of arms. modified commercial LLS spectrometer equipped with a multi-τ digital time correlator and a cylindrical 22 mW UNIPHASE He-Ne laser was used to characterize each solution before and after it passed through the nanopores. The incident beam was vertically polarized with respect to the scattering plane.

Dai J.,University of Nebraska - Lincoln | Zhao Y.,University of Nebraska - Lincoln | Wu X.,Anhui University of Science and Technology | Yang J.,Anhui University of Science and Technology | And 2 more authors.
Journal of Physical Chemistry Letters | Year: 2013

The most stable structures of two-dimensional (2D) boron-silicon (B-Si) compounds containing planar sp2-bonding silicon (sp2-Si) are explored using the first-principles calculation-based particle-swarm optimization method. Among 10 B-Si compounds considered, we find that for BSi4, BSi3, BSi, B2Si, B3Si, B 5Si, and B6Si, each Si atom is bonded with three B or Si atoms within the same plane, representing a preference of planar sp 2-Si structure in B-Si compounds. For BSi2 and B 4Si, the predicted lowest-energy structures entail a small out-of-plane buckling. Furthermore, a planar-tetracoordinated Si (ptSi) atom bonded with four B atoms within the same plane is observed in the lowest-energy structure of B7Si compound. Dynamical stabilities of the predicted 10 2D B-Si compounds are confirmed via phonon-spectrum calculation. The lowest-energy 2D B-Si compounds are all metals, regardless of the B-Si stoichiometry considered in this study. © 2013 American Chemical Society.

Dai J.,University of Nebraska - Lincoln | Wu X.,CAS Hefei Key Laboratory of Materials for Energy Conversion | Wu X.,Anhui University of Science and Technology | Yang J.,Anhui University of Science and Technology | And 2 more authors.
Journal of Physical Chemistry Letters | Year: 2013

Two metallic zeolite-like microporous BN crystals with all-sp2 bonding networks are predicted from an unbiased structure search based on the particle-swarm optimization (PSO) algorithm in combination with first-principles density functional theory (DFT) calculations. The stabilities of both microporous structures are confirmed via the phonon spectrum analysis and Born-Oppenheimer molecular dynamics simulations with temperature control at 1000 K. The unusual metallicity for the microporous BN allotropes stems from the delocalized p electrons along the axial direction of the micropores. Both microporous BN structures entail large surface areas, ranging from 3200 to 3400 m2/g. Moreover, the microporous BN structures show a preference toward organic molecule adsorption (e.g., the computed adsorption energy for CH3CH2OH is much more negative than that of H 2O). This preferential adsorption can be exploited for water cleaning, as demonstrated recently using porous boron BN nanosheets (Nat. Commun. 2013, 4, 1777). © 2013 American Chemical Society.

Feng D.-J.,Chinese University of Hong Kong | Huang W.,Anhui University of Science and Technology
Communications in Mathematical Physics | Year: 2010

For general asymptotically sub-additive potentials (resp. asymptotically additive potentials) on general topological dynamical systems, we establish some variational relations between the topological entropy of the level sets of Lyapunov exponents, measure-theoretic entropies and topological pressures in this general situation. Most of our results are obtained without the assumption of the existence of unique equilibrium measures or the differentiability of pressure functions. Some examples are constructed to illustrate the irregularity and the complexity of multifractal behaviors in the sub-additive case and in the case that the entropy map is not upper-semi continuous. © 2010 Springer-Verlag.

Zhao W.-H.,Anhui University of Science and Technology | Bai J.,University of Nebraska - Lincoln | Yuan L.-F.,Anhui University of Science and Technology | Yang J.,Anhui University of Science and Technology | Zeng X.C.,University of Nebraska - Lincoln
Chemical Science | Year: 2014

Two new phases of water, the mid-density hexagonal monolayer ice and the high-density flat rhombic monolayer ice, are observed in our molecular dynamics simulations of monolayer water confined between two smooth hydrophobic walls. These are in addition to the two monolayer ices reported previously, namely, the low-density 4·82 monolayer ice and the high-density puckered rhombic monolayer ice (HD-pRMI). Stabilities of the structures are confirmed by ab initio computation. Importantly, both new phases and the HD-pRMI are predicted to be ferroelectric. An in-plane external electric field can further stabilize these ferroelectric monolayer ices. © 2014 the Partner Organisations.

Jiang H.-L.,Texas A&M University | Jiang H.-L.,Anhui University of Science and Technology | Makal T.A.,Texas A&M University | Zhou H.-C.,Texas A&M University
Coordination Chemistry Reviews | Year: 2013

Interpenetration in metal-organic frameworks (MOFs) is an intriguing phenomenon with significant impacts on the structure, porous nature, and functional applications of MOFs. In this review, we provide an overview of interpenetration involved in MOFs or coordination polymers with different dimensionalities and property changes (especially gas uptake capabilities and catalysis) caused by framework interpenetration. Successful approaches for control of interpenetration in MOFs have also been introduced and summarized. © 2013 .

Yue Y.,Chinese University of Hong Kong | Wu C.,Chinese University of Hong Kong | Wu C.,Anhui University of Science and Technology
Biomaterials Science | Year: 2013

The development of safe, efficient and controllable gene-delivery vectors has become a bottleneck to human gene therapy. Synthetic polymeric vectors, although safer than viral carriers, generally do not possess the required efficacy, apparently due to a lack of functionality to overcome at least one of many intracellular gene-delivery obstacles. Currently, the exact mechanisms of how these polymeric vectors navigate each intracellular obstacle ("slit"), as well as their particular physical/chemical properties that contribute to efficient intracellular trafficking remain largely unknown, making it rather difficult to further improve the efficacy of non-viral polymeric vectors in vitro and in vivo. In this review, we first give a brief overview of synthetic polymeric vectors that have been designed and developed for gene delivery and highlight some promising candidates for clinical applications. Our main focus is on discussing the intracellular trafficking mechanisms of the DNA-polymer complexes ("polyplexes"), with less effort on the DNA-polymer complexation in the extracellular space as well as the in vivo systemic administration of genes in animal models and human clinical trials. In particular, we identified and discussed four critical, but often over-looked issues for successful DNA-polymer intracellular trafficking, especially our recent confirmation that it is free cationic polymer chains in the solution mixture of DNA and polymer that actually promote gene transfection and the polycationic chains within the polyplexes mainly play a protective role. Instead of the previously proposed and widely used escape model from late endolysosomes, the current hypothesis is that free polycationic chains with a sufficient length (∼20 nm) can block the initial endocytic-vesicle-to- endolysosome pathway. © 2013 The Royal Society of Chemistry.

Cai Y.-F.,McGill University | Zhao W.,Anhui University of Science and Technology | Zhang Y.,Anhui University of Science and Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2014

The hemispherical power asymmetry in the cosmic microwave background can be explained by the modulation of some primordial cosmological parameters, such as the sound speed of the inflaton. Inspired by new physics beyond the standard knowledge of particle cosmology, this sound speed modulation greatly enriches the cosmological perturbation theory. We numerically examine the mechanism of the sound speed modulation and show it can be nicely consistent with current observations. Furthermore, this mechanism predicts that power asymmetry also exists in the temperature-polarization correlation and polarization autocorrelation of the cosmic microwave background with the same shape and in primordial non-Gaussianity of equilateral type with a particular shape. Therefore, our mechanism is observationally detectable in the forthcoming experiments. © 2014 American Physical Society.

Jiang H.-L.,Texas A&M University | Jiang H.-L.,Anhui University of Science and Technology | Feng D.,Texas A&M University | Wang K.,Texas A&M University | And 4 more authors.
Journal of the American Chemical Society | Year: 2013

A reaction between a ZrIV salt and a porphyrinic tetracarboxylic acid leads to a metal-organic framework (MOF) with two types of open channels, representing a MOF featuring a (4,8)-connected sqc net. The MOF remains intact in both boiling water and aqueous solutions with pH ranging from 1 to 11, a remarkably extensive pH range that a MOF can sustain. Given its exceptional stability and pH-dependent fluorescent intensity, the MOF can potentially be applied in fluorescent pH sensing. © 2013 American Chemical Society.

Wu C.,Chinese University of Hong Kong | Wu C.,Anhui University of Science and Technology
Macromolecules | Year: 2012

Chain confinement and translocation in and through a small pore is studied to find why RNA and protein chains are linear and not colliding inside nuclear pores. Experimental and theoretical results show that RNA and protein chains are linear. If they were branched, the critical flow rate for them to pass through nuclear pores would be varying for different branching structures and different molar masses, but the thermally agitated motions of a nuclear membrane are passive such that the induced flow rate cannot be automatically adjusted for branched chains with different structures. Studied have also found that there is sufficient time for a linear RNA or protein chain to pass through a nuclear pore completely without being driven back and forth inside a nuclear pore by the breathing motions.

Dai Z.,Chinese University of Hong Kong | Wu C.,Chinese University of Hong Kong | Wu C.,Anhui University of Science and Technology
Macromolecules | Year: 2012

Complexation between DNA with anionic charges (P) and polyethylenimine (PEI) with cationic charges (N) in aqueous solution condenses DNA into small insoluble aggregates (polyplexes), facilitating its delivery into cells. The study of the captioned problem is long overdue. Using a combination of static and dynamic laser light scattering, we showed that for a given topology PEI with a high molar mass is more effective in condensing DNA, while for a given molar mass, linear chains are more efficient in neutralizing DNA than their branched counterparts. The resultant polyplexes become stable when N/P ≥ 6 and, quantitatively, on average contain only one DNA. The ratio of gyration to hydrodynamic radii decreases after the DNA and PEI complexation but increases with the N/P ratio. This study reveals that linear chains can align themselves on DNA to effectively neutralize its anionic charges so that DNA collapses in water mainly due to its insolubility like a neutral hydrocarbon chain, while cationic branched chains condense each DNA chain mainly by pulling its intrachain anionic segments together and coat its periphery to form a mushroom-like PEI shell. Such two different condensation ways are supported by the results of adding strong polyanions (dextran sulfate, DS) into the polyplexes dispersion; namely, DS can ripe linear chains away from each polyplex layer by layer, like peeling an onion, to completely release DNA, but mostly strip cationic branched chains coated on the periphery, not those inside, to partially release DNA. © 2012 American Chemical Society.

Rui G.,University of Dayton | Rui G.,Anhui University of Science and Technology | Nelson R.L.,Air Force Research Lab | Zhan Q.,University of Dayton
Optics Letters | Year: 2011

In this Letter, we study the emission properties of an electric dipole emitter coupled to a plasmonic spiral structure. The plasmonic spiral structure functions as an optical antenna, coupling the electric dipole emission into circularly polarized unidirectional emission in the far field. Increasing number of turns of the spiral leads to narrower angular width of the emission pattern in the far field. For a spiral antenna with six turns, antenna directivity of 23:5 dB with a directional emission into a narrow angular cone of 4:3° can be achieved. The emitted photons carry spin that is essentially determined by the handedness of the spiral antenna. By reversing the spiral, one can switch the polarization of the emission field between left-hand and right-hand circular polarizations. The spiral antenna may be used as a nanoscale circular polarization source in single molecule sensing, single-photo sources, and integrated photonic circuits. © 2011 Optical Society of America.

Ding G.-J.,Anhui University of Science and Technology | Ding G.-J.,University of Wisconsin - Madison | Meloni D.,Third University of Rome
Nuclear Physics B | Year: 2012

We propose a new A4 model in which both the right-handed neutrinos and right-handed charged leptons transform as A4 singlets. We reproduce tri-bimaximal mixing pattern exactly although the A4 symmetry is broken completely at leading order in both the neutrino and charged lepton sectors. The charged lepton mass hierarchies are controlled by the spontaneous breaking of the flavor symmetry. The light neutrino spectrum is predicted to be of normal type and the lightest neutrino is massless at leading order. Although the reactor angle θ13 is expected to be of order λc2 from the next to leading order corrections, this model cannot be ruled out by current experimental data including the latest T2K results. Leptogenesis is realized via the resonant leptogenesis of the second and the third heavy right-handed neutrinos which are degenerate at leading order. The phenomenological consequences for lepton flavor violation are discussed in detail. © 2011 Elsevier B.V.

Evans E.J.,Brigham Young University | Scott M.A.,Brigham Young University | Li X.,Anhui University of Science and Technology | Thomas D.C.,Brigham Young University
Computer Methods in Applied Mechanics and Engineering | Year: 2014

In this paper hierarchical analysis-suitable T-splines (HASTS) are developed. The resulting spaces are a superset of both analysis-suitable T-splines and hierarchical B-splines. The additional flexibility provided by the hierarchy of T-spline spaces results in simple, highly localized refinement algorithms which can be utilized in a design or analysis context. A detailed theoretical formulation is presented. Bézier extraction is extended to HASTS simplifying the implementation of HASTS in existing finite element codes. The behavior of a simple HASTS refinement algorithm is compared to the local refinement algorithm for analysis-suitable T-splines demonstrating the superior efficiency and locality of the HASTS algorithm. Finally, HASTS are utilized as a basis for adaptive isogeometric analysis. © 2014 Elsevier B.V.

Rui G.,University of Dayton | Rui G.,Anhui University of Science and Technology | Nelson R.L.,Air Force Research Lab | Zhan Q.,University of Dayton
Optics Express | Year: 2012

We analytically and numerically study the emission properties of an electric dipole coupled to a plasmonic spiral structure with different pitch. As a transmitting antennathe spiral structure couples the radiation from the electric dipole into circularly polarized emitted photons in the far field. The spin carried by the emitted photons is determined by the handedness of the spiral antenna. By increasing the spiral pitch in the unit of surface plasmon wavelengththese circularly polarized photons also gain orbital angular momentum with different topological charges. This phenomenon is attributed to the presence of a geometric phase arising from the interaction of light from point source with the anisotropic spiral structure. The circularly polarized vortex emission from such optically coupled spiral antenna also has high directivitywhich may find important applications in quantum optical informationsingle molecule sensingand integrated photonic circuits. © 2012 Optical Society of America.

Hua R.,Anhui University of Science and Technology | Zhu L.,Indiana University – Purdue University Indianapolis | Lu X.,Anhui University of Science and Technology
Physics of Fluids | Year: 2013

The locomotion of a flapping flexible plate in a viscous incompressible stationary fluid is numerically studied by an immersed boundary-lattice Boltzmann method for the fluid and a finite element method for the plate. When the leading-edge of the flexible plate is forced to heave sinusoidally, the entire plate starts to move freely as a result of the fluid-structure interaction. Mechanisms underlying the dynamics of the plate are elucidated. Three distinct states of the plate motion are identified and can be described as forward, backward, and irregular. Which state to occur depends mainly on the heaving amplitude and the bending rigidity of the plate. In the forward motion regime, analysis of the dynamic behaviors of the flapping flexible plate indicates that a suitable degree of flexibility can improve the propulsive performance. Moreover, there exist two kinds of vortex streets in the downstream of the plate which are normal and deflected wake. Further the forward motion is compared with the flapping-based locomotion of swimming and flying animals. The results obtained in the present study are found to be consistent with the relevant observations and measurements and can provide some physical insights into the understanding of the propulsive mechanisms of swimming and flying animals. © 2013 AIP Publishing LLC.

Wang J.,Anhui University of Science and Technology | Liu G.-Z.,Anhui University of Science and Technology | Liu G.-Z.,Max Planck Institute For Physik Komplexer Systeme
New Journal of Physics | Year: 2013

We investigate the competition between the d-wave superconductivity and the nematic order in the high-Tc superconductor and examine the role played by the gapless fermionic degrees of freedom. Apart from the competitive interaction with the superconducting order parameter, the nematic order parameter couples strongly to gapless nodal quasiparticles. The interplay of these two kinds of interactions is analyzed by means of the renormalization group method. In case the fermionic degrees of freedom are entirely neglected, the competitive interaction between the two bosonic order parameters is strongly relevant and can lead to runaway behavior. However, these properties are fundamentally changed once the dynamics of the fermions are taken into account. At the nematic quantum critical point where an extreme fermion velocity anisotropy occurs, the superconducting and nematic order parameters are decoupled from each other. Consequently, the phase transitions are continuous and the d-wave superconductivity can coexist with the nematic order homogeneously. These results indicate that the gapless fermions can play an important role and should be carefully included in the theoretical description of competing orders. © IOP Publishing and Deutsche Physikalische Gesellschaft.

Tian F.-B.,Vanderbilt University | Luo H.,Vanderbilt University | Song J.,Vanderbilt University | Lu X.-Y.,Anhui University of Science and Technology
Journal of Fluids and Structures | Year: 2013

Insect wings usually are flexible and deform significantly under the combined inertial and aerodynamic load. To study the effect of wing flexibility on both lift and thrust production in forward flight, a two-dimensional numerical simulation is employed to compute the fluid-structure interaction of an elastic wing section translating in an inclined stroke plane while pitching around its leading ledge. The effects of the wing stiffness, mass ratio, stroke plane angle, and flight speed are considered. The results show that the passive pitching due to wing deformation can significantly increase thrust while either maintaining lift at the same level or increasing it simultaneously. Another important finding is that even though the wing structure and actuation kinematics are symmetric, chordwise deformation of the wing shows a larger magnitude during upstroke than during downstroke. The asymmetry is more pronounced when the wing has a low mass ratio so that the fluid-induced deformation is significant. Such an aerodynamic cause may serve as an additional mechanism for the asymmetric deformation pattern observed in real insects. © 2012 Elsevier Ltd.

Li L.,Fudan University | Yu Y.,Fudan University | Ye G.J.,Anhui University of Science and Technology | Ge Q.,Fudan University | And 5 more authors.
Nature Nanotechnology | Year: 2014

Two-dimensional crystals have emerged as a class of materials that may impact future electronic technologies. Experimentally identifying and characterizing new functional two-dimensional materials is challenging, but also potentially rewarding. Here, we fabricate field-effect transistors based on few-layer black phosphorus crystals with thickness down to a few nanometres. Reliable transistor performance is achieved at room temperature in samples thinner than 7.5 nm, with drain current modulation on the order of 10 5 and well-developed current saturation in the I-V characteristics. The charge-carrier mobility is found to be thickness-dependent, with the highest values up to 1/41,000 cm 2 V 1 s 1 obtained for a thickness of 1/410 nm. Our results demonstrate the potential of black phosphorus thin crystals as a new two-dimensional material for applications in nanoelectronic devices. © 2014 Macmillan Publishers Limited. All rights reserved.

Wang J.-R.,Anhui University of Science and Technology | Liu G.-Z.,Max Planck Institute For Physik Komplexer Systeme
New Journal of Physics | Year: 2012

There is an interesting proposal that the long-range Coulomb interaction in suspended graphene can generate a dynamical gap, which leads to a semimetal-insulator phase transition. We revisit this problem by solving the self-consistent Dyson-Schwinger equations of wave function renormalization and fermion gap. In order to satisfy the Ward identity, a suitable vertex function is introduced. The impact of singular velocity renormalization and that ofdynamical screening on gap generation are both included in this formalism, and prove to be very important. We obtain a critical interaction strength, 3.2 < α c < 3.3, which is larger than the physical value α = 2.16 for suspended graphene. It therefore turns out that suspended graphene is a semimetal, rather than an insulator, at zero temperature. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.

Xiang H.J.,Fudan University | Huang B.,National Renewable Energy Laboratory | Li Z.Y.,Anhui University of Science and Technology | Wei S.-H.,National Renewable Energy Laboratory | And 2 more authors.
Physical Review X | Year: 2012

The interaction between substitutional nitrogen atoms in graphene is studied by performing firstprinciples calculations. The effective nearest-neighbor interaction between nitrogen dopants is found to be highly repulsive because of the strong electrostatic repulsion between nitrogen atoms. This interaction prevents the full nitrogen-carbon phase separation in nitrogen-doped graphene. Interestingly, there are two relatively stable nitrogen-nitrogen pair configurations, whose stability can be attributed to the anisotropy in the charge redistribution induced by nitrogen doping. We reveal two stable, ordered, semiconducting N-doped graphene structures, C 3N and C 12N, through the cluster-expansion technique and particle-swarm optimization method. In particular, we show that C 12N has a direct band gap of 0.98 eV. The heterojunctions between C 12N and graphene nanoribbons might be a promising basis for organic solar cells.

Tian F.-B.,Vanderbilt University | Lu X.-Y.,Anhui University of Science and Technology | Luo H.,Vanderbilt University
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2012

A body with a traveling-wave surface (TWS) is investigated by solving the incompressible Navier-Stokes equation numerically to understand the mechanisms of a novel propulsive strategy. In this study, a virtual model of a foil with a flexible surface which performs a traveling-wave movement is used as a free swimming body. Based on the simulations by varying the traveling-wave Reynolds number and the amplitude and wave number of the TWS, some propulsive properties including the forward speed, the swimming efficiency, and the flow field are analyzed in detail. It is found that the mean forward velocity increases with the traveling-wave Reynolds number, the amplitude, and the wave number of the TWS. A weak wake behind the free swimming body is identified and the propulsive mechanisms are discussed. Moreover, the TWS is a "quiet" propulsive approach, which is an advantage when preying. The results obtained in this study provide a novel propulsion concept, which may also lead to an important design capability for underwater vehicles. © 2012 American Physical Society.

Shi J.-J.,Nanjing University | Shi J.-J.,Anhui University of Science and Technology | Zhu J.-J.,Nanjing University
Electrochimica Acta | Year: 2011

A novel electrochemical sensor for chlorophenols was fabricated by using the Pd-graphene nanocomposite and ions liquid. The Pd-graphene nanocomposite was prepared via a sonoelectrochemical route, and the possible formation mechanism was proposed. Transmission electron microscopy, scanning electron microscopy, X-ray diffraction and Raman spectrum were used for the characterization of structure and morphology of the nanocomposite. The experimental results showed that Pd nanospheres comprised of small Pd nanoparticles were uniformly attached on graphene sheets. The electrocatalytic properties were investigated by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), which indicated that the Pd-graphene nanocomposite had high activity for chlorophenol oxidation. Herein, 2-chlorophenol was selected as the model molecules. The results showed that graphene played an important role in the fabrication of the chlorophenols sensor. The nanocomposite with large electrochemical active surface led to the excellent electrocatalytic activity, and ionic liquid further enhanced the catalytic activity of Pd-graphene for chlorophenols. © 2011 Elsevier Ltd. All Rights Reserved.

Hu Y.,Anhui University of Science and Technology | Verdegaal W.M.,Sunfire GmbH | Yu S.-H.,Anhui University of Science and Technology | Jiang H.-L.,Anhui University of Science and Technology
ChemSusChem | Year: 2014

Different alkylamine molecules were post-synthetically tethered to the unsaturated CrIII centers in the metal-organic framework MIL-101. The resultant metal-organic frameworks show almost no N2 adsorption with significantly enhanced CO2 capture under ambient conditions as a result of the interaction between amine groups and CO2 molecules. Given the extraordinary stability, high CO2 uptake, ultrahigh CO 2/N2 selectivity, and mild regeneration energy, MIL-101-diethylenetriamine holds exceptional promise for post-combustion CO 2 capture and CO2/N2 separation. Amenable amines: Alkylamine molecules are post-synthetically tethered to the unsaturated CrIII centers in the metal-organic framework (MOF) MIL-101. The resultant MOFs show significantly enhanced CO2 capture as a result of the interaction between amine groups and CO2 molecules. With extraordinary stability, high CO2 uptake, ultrahigh CO 2/N2 selectivity, and mild regeneration energy, MIL-101-diethylenetriamine holds exceptional promise for post-combustion CO 2 capture and CO2/N2 separation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shao Q.,Soochow University of China | Shao Q.,Anhui University of Science and Technology | Que R.,Soochow University of China | Shao M.,Soochow University of China | And 2 more authors.
Advanced Functional Materials | Year: 2012

Copper nanoparticles grafted on a silicon wafer are fabricated by reducing copper ions with silicon-hydrogen bonds and assembling them in situ on the Si wafer. The nanoparticles, with an average size of 20 nm, grow uniformly and densely on the Si wafer, and they are used as substrates for surface-enhanced Raman scattering. These substrates exhibit excellent enhancement in the low concentration detection (1 × 10 -9 M) of rhodamine 6G with an enhancement factor (EF) of 2.29 × 10 7 and a relative standard deviation (RSD) of <20%. They are also employed to detect sudan-I dye with distinguished sensitivity and uniformity. The results are interesting and significant because Cu substrates are otherwise thought to be poor. These effects might provide new ways to think about surface-enhanced Raman scattering based on Cu substrates. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

You B.,Anhui University of Science and Technology | Jiang J.,Anhui University of Science and Technology | Fan S.,Auburn University
ACS Applied Materials and Interfaces | Year: 2014

Three-dimensional hierarchically porous carbon-CNT-graphene ternary all-carbon foams (3D-HPCFs) with 3D macro- and mesoporous structures, a high specific surface area (1286 m2g-1), large bimodal mesopores (5.1 and 2.7 nm), and excellent conductivity have been fabricated through multicomponent surface self-assembly of graphene oxide (GO)-dispersed pristine CNTs (GOCs) supported on a commercial sponge. The commercial sponge with a 3D interconnected macroporous framework not only is used as a support for GOCs and subsequently multicomponent self-assembly but also serves as a 3D scaffold to buffer electrolytes to reduce ion transport resistance and ion diffusion distance, while the GO acts as "surfactant" to directly disperse pristine CNTs, preserving the excellent electronic structure of pristine CNTs, and the CNTs also prevent the aggregation of graphene as well as improve the whole conductivity. Benefiting from the aforementioned characteristics, the 3D-HPCFs-based supercapacitors show outstanding specific capacitance, high rate capability, and excellent cycling stability, making them potentially promising for high-performance energy storage devices. © 2014 American Chemical Society.

Yan J.-J.,Anhui University of Science and Technology | Wang D.,Anhui University of Science and Technology | Wu D.-C.,CAS Beijing National Laboratory for Molecular | You Y.-Z.,Anhui University of Science and Technology
Chemical Communications | Year: 2013

Sequence-ordered polymers can be simply prepared in one pot via sequential monomer addition. © 2013 The Royal Society of Chemistry.

Huang H.-L.,Shandong University | Liu G.,Nanjing University | Ye Y.,Anhui University of Science and Technology
Communications in Mathematical Physics | Year: 2011

We study finite quasi-quantum groups in their quiver setting developed recently by the first author. We obtain a classification of finite-dimensional pointed Majid algebras of finite corepresentation type, or equivalently a classification of elementary quasi-Hopf algebras of finite representation type, over the field of complex numbers. By the Tannaka-Krein duality principle, this provides a classification of the finite tensor categories in which every simple object has Frobenius-Perron dimension 1 and there are finitely many indecomposable objects up to isomorphism. Some interesting information of these finite tensor categories is given by making use of the quiver representation theory. © 2011 Springer-Verlag.

Shi J.-J.,Nanjing University | Shi J.-J.,Anhui University of Science and Technology | Yang G.-H.,Nanjing University | Zhu J.-J.,Nanjing University
Journal of Materials Chemistry | Year: 2011

Sonoelectrochemical technique was successfully used to fabricate alloy-graphene nanocomposites. It not only provides a simple way to synthesize alloy nanoparticles, but also shows a general strategy for fabricating graphene-based nanostructures with anticipated properties. Pd was co-electrodeposited with Pt at different atomic ratios, and then was anchored with reduced graphene oxide (RGO) simultaneously in the presence of PDDA. The morphologies and structures of the as-prepared PDDA-RGO-PdPt nanocomposites were extensively investigated by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The composition was evaluated by energy dispersive X-ray spectrometry (EDS) and inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Raman spectra revealed the surface properties of graphene and its interaction with metallic nanoparticles. Cyclic voltammetric (CV) and chronoamperometric experiments further exhibited their catalytic activity and stability for the electro-oxidation of ethanol in alkaline media, which could be applied as promising electrocatalysts for direct alcohol fuel cells (DAFCs). © 2011 The Royal Society of Chemistry.

Song H.,CAS Beijing National Laboratory for Molecular | Niu Y.,CAS Beijing National Laboratory for Molecular | Wang Z.,Anhui University of Science and Technology | Zhang J.,CAS Beijing National Laboratory for Molecular
Biomacromolecules | Year: 2011

Liquid crystalline (LC) phase transition and gel-sol transition in the solutions of microcrystalline cellulose (MCC) and ionic liquid (1-ethyl-3-methylimidazolium acetate, EMIMAc) have been investigated through a combination of polarized optical microscope (POM) observation and rheological measurements. Molecular LC phase forms at the 10 wt % cellulose concentration, as observed by POM, whereas the critical gel point is 12.5 wt % by rheological measurements according to the Winter and Chambon theory, for which the loss tangent, tan, shows frequency independence. Dramatic decreases of G' and G'' in the phase transition temperature range during temperature sweep are observed due to disassembling of the LC domain junctions. The phase diagram describing the LC phase and gel-sol transitions is obtained and the associated mechanisms are elucidated. A significant feature shown in the phase diagram is the presence of a narrow lyotropic LC solution region, which potentially has a great importance for the cellulose fiber wet spinning. © 2011 American Chemical Society.

Wang R.-B.,Anhui University of Science and Technology | Feng H.-Y.,Nanjing University of Science and Technology
Guangdianzi Jiguang/Journal of Optoelectronics Laser | Year: 2010

By using the tunable diode laser absorption spectroscopy(TDLAS) technology the absorption line of methane at the wavelength of 1653.72 nm is found to be free of interference and suitable for the measurement of coal mine methane. The high performance microcontroller(DSP) and second harmonic detection are used to lower the detection limit further that is below 0.074 mg/m3. It has an obvious advantage in sensitivity and stability and can achieve real-time measurement of the coal mine methane.

Kan E.,Nanjing University of Science and Technology | Hu W.,Anhui University of Science and Technology | Xiao C.,Nanjing University of Science and Technology | Lu R.,Nanjing University of Science and Technology | And 3 more authors.
Journal of the American Chemical Society | Year: 2012

The unprecedented applications of two-dimensional (2D) atomic sheets in spintronics are formidably hindered by the lack of ordered spin structures. Here we present first-principles calculations demonstrating that the recently synthesized dimethylmethylene-bridged triphenylamine (DTPA) porous sheet is a ferromagnetic half-metal and that the size of the band gap in the semiconducting channel is roughly 1 eV, which makes the DTPA sheet an ideal candidate for a spin-selective conductor. In addition, the robust half-metallicity of the 2D DTPA sheet under external strain increases the possibility of applications in nanoelectric devices. In view of the most recent experimental progress on controlled synthesis, organic porous sheets pave a practical way to achieve new spintronics. © 2012 American Chemical Society.

Jin H.,Anhui University of Science and Technology | Safonov M.G.,University of Southern California
International Journal of Adaptive Control and Signal Processing | Year: 2012

Controller switching algorithms used for adaptive control are investigated. The concept of interfalsification, a generalization of the existing ε-hysteresis algorithm, is defined; a new concept of self-falsification is introduced, and the two concepts are compared. On the basis of the idea of self-falsification, new controller switching algorithms are designed and two new convergence theorems are proved. These new results allow for removal of the assumption that the cost function associated with each controller be monotonically nondecreasing in time, thus opening the possibility of safe data-driven adaptive control designs with fading-memory cost functions. Theoretical analysis and simulations illustrate that the self-falsification algorithms can also decrease insertions of destabilizing controllers and improve the transient properties. Copyright © 2012 John Wiley & Sons, Ltd.

Yang K.,Soochow University of China | Xu H.,Soochow University of China | Cheng L.,Soochow University of China | Sun C.,Anhui University of Science and Technology | And 2 more authors.

Poly(vinyl alcohol)-coated polypyrole, a conductive polymer that forms nanoparticles in the aqueous phase, is used as a near-infrared light-absorbing agent for photothermal therapy of cancer, obtaining excellent cancer ablation therapeutic effects in both cellular and animal experiments. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Feng L.,Soochow University of China | Yang X.,Anhui University of Science and Technology | Shi X.,Soochow University of China | Tan X.,Soochow University of China | And 3 more authors.
Small | Year: 2013

Graphene oxide (GO) has been extensively explored in nanomedicine for its excellent physiochemical, electrical, and optical properties. Here, polyethylene glycol (PEG) and polyethylenimine (PEI) are covalently conjugated to GO via amide bonds, obtaining a physiologically stable dual-polymer-functionalized nano-GO conjugate (NGO-PEG-PEI) with ultra-small size. Compared with free PEI and the GO-PEI conjugate without PEGylation, NGO-PEG-PEI shows superior gene transfection efficiency without serum interference, as well as reduced cytotoxicity. Utilizing the NIR optical absorbance of NGO, the cellular uptake of NGO-PEG-PEI is shown to be enhanced under a low power NIR laser irradiation, owing to the mild photothermal heating that increases the cell membrane permeability without significantly damaging cells. As the results, remarkably enhanced plasmid DNA transfection efficiencies induced by the NIR laser are achieved using NGO-PEG-PEI as the light-responsive gene carrier. More importantly, it is shown that our NGO-PEG-PEI is able to deliver small interfering RNA (siRNA) into cells under the control of NIR light, resulting in obvious down-regulation of the target gene, Polo-like kinase 1 (Plk1), in the presence of laser irradiation. This study is the first to use photothermally enhanced intracellular trafficking of nanocarriers for light-controllable gene delivery. This work also encourages further explorations of functionalized nano-GO as a photocontrollable nanovector for combined photothermal and gene therapies. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang C.,Soochow University of China | Cheng L.,Soochow University of China | Liu Y.,Soochow University of China | Wang X.,Soochow University of China | And 4 more authors.
Advanced Functional Materials | Year: 2013

Photodynamic therapy (PDT) based on upconversion nanoparticles (UCNPs) can effectively destroy cancer cells under tissue-penetrating near-infrared light (NIR) light. Herein, we synthesize manganese (Mn2+)-doped UCNPs with strong red light emission at ca. 660 nm under 980 nm NIR excitation to activate Chlorin e6 (Ce6), producing singlet oxygen (1O2) to kill cancer cells. A layer-by-layer (LbL) self-assembly strategy is employed to load multiple layers of Ce6 conjugated polymers onto UCNPs via electrostatic interactions. UCNPs with two layers of Ce6 loading (UCNP@2xCe6) are found to be optimal in terms of Ce6 loading and 1O2 generation. By further coating UCNP@2xCe6 with an outer layer of charge-reversible polymer containing dimethylmaleic acid (DMMA) groups and polyethylene glycol (PEG) chains, we obtain a UCNP@2xCe6-DMMA-PEG nanocomplex, the surface of which is negatively charged and PEG coated under pH 7.4; this could be converted to have a positively charged naked surface at pH 6.8, significantly enhancing cell internalization of nanoparticles and increasing in vitro NIR-induced PDT efficacy. We then utilize the intrinsic optical and paramagnetic properties of Mn2+-doped UCNPs for in vivo dual modal imaging, and uncover an enhanced retention of UCNP@2xCe6-DMMA-PEG inside the tumor after intratumoral injection, owing to the slightly acidic tumor microenvironment. Consequently, a significantly improved in vivo PDT therapeutic effect is achieved using our charge-reversible UCNP@2xCe6-DMMA-PEG nanoparticles. Finally, we further demonstrate the remarkably enhanced tumor-homing of these pH-responsive charge-switchable nanoparticles in comparison to a control counterpart without pH sensitivity after systemic intravenous injection. Our results suggest that UCNPs with finely designed surface coatings could serve as smart pH-responsive PDT agents promising in cancer theranostics. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yang C.-F.,Anhui University of Science and Technology | Shen C.,Anhui University of Science and Technology | Wang J.-Y.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Organic Letters | Year: 2012

A range of protected γ-oxo-α-amino esters have been prepared in a highly regio- and stereoselective manner through the decarboxylative Mannich reaction of β-keto acids with optically active N-tert-butanesulfinyl α-imino esters in the presence of 3 mol % La(OTf) 3 or 5 mol % Y(OTf) 3 at 20 °C. Preliminary mechanistic studies indicate that the reaction proceeds through imine addition followed by decarboxylation. © 2012 American Chemical Society.

Jorn R.,Northwestern University | Zhao J.,Anhui University of Science and Technology | Petek H.,University of Pittsburgh | Seideman T.,Northwestern University
ACS Nano | Year: 2011

We introduce a new paradigm for single molecule devices based on electronic actuation of the internal atom/cluster motion within a fullerene cage. By combining electronic structure calculations with dynamical simulations, we explore current-triggered dynamics in endohedrally doped fullerene molecular junctions. Inelastic electron tunneling through a Li atom localized resonance in the Au-Li@C60-Au junction initiates fascinating, strongly coupled 2D dynamics, wherein the Li atom exhibits large amplitude oscillation with respect to the fullerene wall and the fullerene cage bounces between the gold electrodes, slightly perturbed by the embedded atom motion. Implications to the fields of single molecule electronics and nanoelectromechanical systems are discussed. © 2011 American Chemical Society.

Feng M.,University of Pittsburgh | Sun H.,Anhui University of Science and Technology | Zhao J.,University of Pittsburgh | Zhao J.,Anhui University of Science and Technology | Petek H.,University of Pittsburgh
ACS Nano | Year: 2014

Efficient capture of CO2 by chemical means requires a microscopic understanding of the interactions of the molecule-substrate bonding and adsorption-induced collective phenomena. By molecule-resolved imaging with scanning tunneling microscopy (STM), we investigate self-catalyzed CO 2 adsorption on one-dimensional (1D) substrates composed of self-assembled metal-organic chains (MOCs) supported on gold surfaces. CO 2 adsorption turns on attractive interchain interactions, which induce pronounced surface structural changes; the initially uniformly dispersed chains gather into close packed bundles, which are held together by highly ordered, single molecule wide CO2 ranks. CO2 molecules create more favorable adsorption sites for further CO2 adsorption by mediating the interchain attraction, thereby self-catalyzing their capture. The release of CO2 molecules by thermal desorption returns the MOCs to their original structure, indicating that the CO2 capture and release are reversible processes. The real space microscopic characterization of the self-catalyzed CO2 adsorption on 1D substrates could be exploited as platform for design of molecular materials for CO2 capture and reduction. © 2014 American Chemical Society.

Cheng D.-J.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Advanced Synthesis and Catalysis | Year: 2013

A range of polysubstituted indolenines (3H-indoles) smoothly underwent an L-proline-catalyzed enantioselective Mannich reaction with various ketones in a highly regioselective manner to give structurally diverse 2-acylmethylindolines in good yields with excellent ee. The current study provides a powerful approach for the transformation of unactivated five-membered cyclic aldimines into optically active nitrogen-containing heterocycles with high enantioselectivity. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jiang Y.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Chemical Science | Year: 2014

This paper describes an efficient method to β-keto methyl sulfones and (E)-vinyl methyl sulfones using DMSO as the substrate. The methyl sulfonyl radical generated from DMSO in the presence of catalytic Cu(i) under O2 atmosphere is believed to be involved in this reaction. Isotopic labeling and 18O2 experiments were performed to investigate the reaction mechanism. © the Partner Organisations 2014.

Xiao H.,Anhui University of Science and Technology | Chai Z.,CAS Shanghai Institute of Organic Chemistry | Zheng C.-W.,CAS Shanghai Institute of Organic Chemistry | Yang Y.-Q.,Anhui University of Science and Technology | And 3 more authors.
Angewandte Chemie - International Edition | Year: 2010

(Figure Presented) Bifunctional catalyst: Simple bifunctional N-Acyl aminophosphines such as 1 were developed to catalyze the first asymmetric [3+2] cycloaddition between allenoates and dual activated olefins. The cycloaddi- tion reactions afford multifunctional chiral cyclopentenes with exclusive regioselectivity, and good to excellent enantioselectivity and yields. © 2010 Wlley-VCH Verlag GmbH &. Co. KGaA, Weinheim.

Weise T.,Anhui University of Science and Technology | Chiong R.,University of Newcastle
Neurocomputing | Year: 2015

Stochastic approaches such as evolutionary algorithms have been widely used in various science and engineering problems. When comparing the performance of a set of stochastic algorithms, it is necessary to statistically evaluate which algorithms are the most suitable for solving a given problem. The outcome of statistical tests comparing N≥2 processes, where N is the number of algorithms, is often presented in tables. This can become confusing for larger numbers of N. Such a scenario is, however, very common in both numerical and combinatorial optimization as well as in the domain of stochastic algorithms in general. In this letter, we introduce an alternative way of visually presenting the results of statistical tests for multiple processes in a compact and easy-to-read manner using a directed acyclic graph (DAG), in the form of a simplified Hasse diagram. The rationale of doing so is based on the fact that the outcome of the tests is always at least a strict partial order, which can be appropriately presented via a DAG. The goal of this brief communication is to promote the use of this approach as a means for presenting the results of comparisons between different optimization methods. © 2014 Elsevier B.V.

Zhao K.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Chemistry - A European Journal | Year: 2014

A highly enantioselective conjugate addition of Grignard reagents to 3-silyl unsaturated esters to deliver synthetically useful chiral β-silylcarbonyl compounds was developed. The synthetic value of this methodology was further illustrated by the synthesis of enantioenriched β-hydroxyl esters and the facile access granted to various α-chiral allylic silanes. A plethora of diastereoselective transformations of β-silylenolates were also investigated and afforded manifold organosilanes that contained contiguous stereogenic centers with excellent enantioselectivity. © 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Maa X.-T.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Advanced Synthesis and Catalysis | Year: 2013

A highly regioselective halogenation reaction of symmetrical and unsymmetrical aromatic azo compounds has been developed at room temperature or at 50 °C. In the presence of 5 mol% palladium diacetate and 0.5 equiv. of p-toluenesulfonic acid, a range of symmetrical aromatic azo compounds smoothly undergo monobromination with N-bromosuccinimide to give the corresponding unsymmetrical aromatic azo compounds in good to excellent yields with >99:1 ortho-selectivity. This chemistry has been successfully extended to unsymmetrical aromatic azo compounds, whose electronricher aryl groups prefer to be monobrominated. Moreover, replacing N-bromosuccinimide with Niodosuccinimide in the reaction allows the synthesis of monoiodinated aromatic azo compounds with >99:1 regioselectivity. © 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Feng C.,Nanyang Technological University | Feng D.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Chemical Communications | Year: 2014

Rh(iii)-catalyzed C-H olefinic alkynylation of enamides for the stereospecific construction of synthetically useful Z-type enynamides is reported. This protocol displays good functionality tolerance and operational simplicity thus providing an alternative synthetic opportunity for the ease of access to specific 1,3-enyne derivatives. © 2014 the Partner Organisations.

Gao S.,University of Kansas | Gao S.,Anhui University of Science and Technology | Hui R.,University of Kansas
Optics Letters | Year: 2012

A frequency-modulated continuous-wave (FMCW) lidar is demonstrated with heterodyne detection. The lidar transmitter utilizes an electro-optic I/Q modulator for the first time to generate carrier-suppressed and frequency-shifted FM modulation. This eliminates the need for an acousto-optic frequency shifter commonly used in heterodyne lidar transmitters. It also allows the use of a much wider modulation bandwidth to improve the range resolution. The capability of complex optical field modulation of the I/Q modulator provides an additional degree of freedom compared with an intensity modulator, which will benefit future lidar applications. © 2012 Optical Society of America.

Yuan C.,Nanyang Technological University | Wu H.B.,Nanyang Technological University | Xie Y.,Anhui University of Science and Technology | Lou X.W.,Nanyang Technological University
Angewandte Chemie - International Edition | Year: 2014

A promising family of mixed transition-metal oxides (MTMOs) (designated as AxB3-xO4; A, B=Co, Ni, Zn, Mn, Fe, etc.) with stoichiometric or even non-stoichiometric compositions, typically in a spinel structure, has recently attracted increasing research interest worldwide. Benefiting from their remarkable electrochemical properties, these MTMOs will play significant roles for low-cost and environmentally friendly energy storage/conversion technologies. In this Review, we summarize recent research advances in the rational design and efficient synthesis of MTMOs with controlled shapes, sizes, compositions, and micro-/nanostructures, along with their applications as electrode materials for lithium-ion batteries and electrochemical capacitors, and efficient electrocatalysts for the oxygen reduction reaction in metal-air batteries and fuel cells. Some future trends and prospects to further develop advanced MTMOs for next-generation electrochemical energy storage/conversion systems are also presented. Full of energy: Recent advances in the rational design and synthesis of mixed transition-metal oxides (MTMOs, designated as AxB3-xO4) with controllable compositions and structures and their applications in various electrochemical energy storage/conversion technologies are summarized and discussed (see picture). Future trends and prospects for their further development are also discussed. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ding G.-J.,Anhui University of Science and Technology | Zhou Y.-L.,CAS Institute of High Energy Physics
Nuclear Physics B | Year: 2013

We present a warped extra dimension model with the custodial symmetry SU(2)L×SU(2)R×U(1)X×PLR based on the flavor symmetry S4×Z2×Z2', and the neutrinos are taken to be Dirac particles. At leading order, the democratic lepton mixing is derived exactly, and the high-dimensional operators introduce corrections of order λc to all the three lepton mixing angles such that agreement with the experimental data can be achieved. The neutrino mass spectrum is predicted to be of the inverted hierarchy and the second octant of θ23 is preferred. We suggest the modified democratic mixing, which is obtained by permuting the second and the third rows of the democratic mixing matrix, should be a good first order approximation to understanding sizable θ13 and the first octant of θ23. The constraints on the model from the electroweak precision measurements are discussed. Furthermore, we investigate the lepton mixing patterns for all the possible residual symmetries Gν and Gl in the neutrino and charged lepton sectors, respectively. © 2013 Elsevier B.V.

Wu X.-S.,Anhui University of Science and Technology | Chen Y.,Anhui University of Science and Technology | Li M.-B.,Anhui University of Science and Technology | Zhou M.-G.,Anhui University of Science and Technology | And 2 more authors.
Journal of the American Chemical Society | Year: 2012

The NH2 group in primary allylic amines was substituted directly by sulfinate salts with excellent regio- and stereoselectivities. In the presence of 0.1 mol % [Pd(allyl)Cl]2, 0.4 mol % 1,4- bis(diphenylphosphino)butane (dppb), and excess boric acid, a range of α-unbranched primary allylic amines were smoothly substituted with sodium sulfinates in an α-selective fashion to give structurally diverse allylic sulfones in good to excellent yields with exclusive E selectivity. Replacing dppb with 1,1′-bi-2-naphthol (BINOL) allowed unsymmetric α-chiral primary allylic amines to be transformed into the corresponding allylic sulfones in good to excellent yields with excellent retention of ee. Importantly, the reaction complements known asymmetric methods in substrate scope via its unique ability to provide α-chiral allylic sulfones with high optical purity starting from unsymmetric allylic electrophiles. © 2012 American Chemical Society.

Su Y.-H.,Anhui University of Science and Technology | Wu Z.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Chemical Communications | Year: 2013

A range of terminal alkenes smoothly underwent palladium-catalyzed oxidative alkoxycarbonylation with carbazates under an oxygen atmosphere to afford structurally diverse α,β-unsaturated esters in moderate to good yields with excellent regioselectivity and E selectivity. This journal is © 2013 The Royal Society of Chemistry.

Yu J.,Anhui University of Science and Technology | Sun J.,CAS Shanghai Institute of Organic Chemistry | Yu B.,CAS Shanghai Institute of Organic Chemistry
Organic Letters | Year: 2012

Direct glycosylation of sugar oximes and HONHFmoc has been realized for the first time by using glycosyl ortho-hexynylbenzoates as donors under the catalysis of PPh3AuOTf, providing an effective approach to the synthesis of N-O linked saccharides, which are of great biological interest. © 2012 American Chemical Society.

Cui Y.-D.,Anhui University of Science and Technology | Yuan Y.-F.,Anhui University of Science and Technology | Li Y.-R.,CAS Institute of High Energy Physics | Wang J.-M.,CAS Institute of High Energy Physics
Astrophysical Journal | Year: 2012

M87 is the first detected non-blazar extragalactic tera-electron-volt (TeV) source with rapid variation and a very flat spectrum in the TeV band. To explain the two peaks in the spectral energy distribution of the nucleus of M87, which is similar to that of blazars, the most commonly adopted models are the synchrotron self-Compton-scattering models and the external inverse Compton (EIC) scattering models. Considering that there is no correlated variation in the soft band (from radio to X-ray) matching the TeV variation and that the TeV sources should not suffer from γγ absorption due to the flat TeV spectrum, the EIC models are advantageous in modeling the TeV emission from M87. In this paper, we propose a self-consistent EIC model to explain the flat TeV spectrum of M87 within the framework of fully general relativity, where the background soft photons are from the advection-dominated accretion flow around the central black hole, and the high-energy electrons are from the mini-jets that are powered by the magnetic reconnection in the main jet. In our model, both the TeV flares observed in the years 2005 and 2008 could be well explained: the γγ absorption for TeV photons is very low, even inside the region very close to the black hole 20Rg ∼ 50Rg ; at the same region, the average EIC cooling time (∼102 ∼10 3 s) is short, which is consistent with the observed timescale of the TeV variation. Furthermore, we also discuss the possibility that the accompanying X-ray flare in 2008 is due to the direct synchrotron radiation of the mini-jets. © 2012. The American Astronomical Society. All rights reserved.

Rujitanaroj P.-O.,Nanyang Technological University | Wang Y.-C.,Anhui University of Science and Technology | Wang J.,Anhui University of Science and Technology | Chew S.Y.,Nanyang Technological University
Biomaterials | Year: 2011

Nanofiber scaffold-mediated delivery of small-interfering RNA (siRNA) holds great potential in regenerative medicine by providing biomimicking topographical signals and enhanced gene silencing effects to seeded cells. While the delivery of naked siRNA was demonstrated previously using poly (ε-caprolactone) (PCL) nanofibers, the resulting siRNA release kinetics and gene knockdown efficiencies were sub-optimal. In this study, we investigated the feasibility of encapsulating siRNA and transfection reagent (TKO) complexes within nanofibers comprising of a copolymer of caprolactone and ethyl ethylene phosphate (PCLEEP, diameter ∼ 400 nm). Sustained release of bioactive naked siRNA and siRNA/TKO complexes were obtained for at least 28 days. By copolymerizing EEP with caprolactone, siRNA release was significantly enhanced (total siRNA that was released by day 49 was ∼ 89.3-97.2% as compared to previously reported 3% by plain PCL nanofiber delivery). Using GAPDH as the model protein, bioactivity analyses by supernatant transfection revealed the partial retention of bioactivity of naked siRNA and siRNA/TKO complexes for at least 30 days. In particular, GAPDH siRNA/TKO supernatant alone induced significant gene silencing (∼40%), indicating the feasibility of co-encapsulating siRNA and transfection reagent within a single scaffold construct for sustained delivery. Direct culture of cells on siRNA incorporated scaffolds for scaffold-mediated gene transfection revealed significant gene knockdown even in the absence of transfection reagent (21.3% knockdown efficiency by scaffolds incorporating naked siRNA only). By encapsulating siRNA/TKO complexes, more significant gene knockdown was obtained (30.9% knockdown efficiency as compared to previously reported 18% by plain PCL scaffold-mediated transfection). Taken together, the results demonstrated the feasibility of co-encapsulating siRNA-transfection reagent complexes within a single nanofiber construct for sustained siRNA delivery and enhanced gene knockdown efficiency. The study also highlights the potential of PCLEEP as a platform for tailoring siRNA release kinetics for long-term gene silencing applications. © 2011 Elsevier Ltd.

Li M.-B.,Anhui University of Science and Technology | Wang Y.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Angewandte Chemie - International Edition | Year: 2012

The NH 2 group serves as an effective leaving group in the palladium-catalyzed regioselective and stereospecific title reaction (see scheme). The reaction works well with aryl- and alkenylboronic acids and aryl-, alkenyl-, allyl-, and benzylboronates, and complete transfer of chirality has been achieved when using α-chiral primary allylic amines as the allylic electrophiles. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shi Z.,Hangzhou Normal University | Shi Z.,Nanyang Technological University | Yu P.,Hangzhou Normal University | Yu P.,Nanyang Technological University | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2012

Under control: The first example of chiral amino phosphine catalysts for the title reaction between vinyl ketones and N-sulfonyl-1-aza-1,3-dienes has been developed. Under ambient conditions, this protocol provides straightforward access to densely functionalized, enantioenriched tetrahydropyridines with high levels of sterecontrol in good to excellent yields. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Xu Y.-H.,Anhui University of Science and Technology | He T.,Anhui University of Science and Technology | Zhang Q.-C.,Anhui University of Science and Technology | Loh T.-P.,Anhui University of Science and Technology | Loh T.-P.,Nanyang Technological University
Chemical Communications | Year: 2014

A cyclization reaction between enamides and alkynes catalyzed by palladium(ii) acetate is described. In this method, the molecular oxygen serves as an efficient oxidant for the Pd(ii)/Pd(0) catalytic cycle. The simple reaction conditions permit this methodology to be used as a general tool for the preparation of multi-substituted pyrroles. © 2014 The Royal Society of Chemistry.

Wang H.-Y.,Anhui University of Science and Technology | Zhang J.-X.,CAS Shanghai Institute of Organic Chemistry | Cao D.-D.,Anhui University of Science and Technology | Zhao G.,Anhui University of Science and Technology | Zhao G.,CAS Shanghai Institute of Organic Chemistry
ACS Catalysis | Year: 2013

Asymmetric phase-transfer catalysis was first applied to the synthesis of chiral N,S-acetals by using amino acid-based bifunctional thiourea-ammonium salt catalysts. The reaction could be performed on the gram scale to give up to 93% ee and 99% yield with a catalyst loading as low as 0.1 mol % within 5 min. © 2013 American Chemical Society.

Shi Z.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology | Loh T.-P.,Nanyang Technological University
Angewandte Chemie - International Edition | Year: 2013

Amines by all means: A unique aza-Rauhut-Currier/cyclization/desulfonation cascade reaction between allenoates and N-sulfonyl-1-aza-1,3-dienes, catalyzed by the readily available diamine TMEDA, has been developed. This strategy provides facile access to a broad range of valuable highly functionalized pyridines in good yields under very mild reaction conditions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang G.,TUM CREATE | Zhang G.,Nanyang Technological University | Xia B.Y.,Nanyang Technological University | Xiao C.,Anhui University of Science and Technology | And 4 more authors.
Angewandte Chemie - International Edition | Year: 2013

Tube in a tube: A general strategy for the fabrication of novel complex tube-in-tube nanostructures for many metal oxides has been developed. The method involves coating carbon nanofibers with a layer of metal glycolate followed by calcination in air. The unique complex tubular structures of metal oxides are shown to exhibit promising properties for the title applications. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhou M.,Anhui University of Science and Technology | Wu H.B.,Nanyang Technological University | Bao J.,Anhui University of Science and Technology | Liang L.,Anhui University of Science and Technology | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2013

Holes in holes: By using a modified colloidal crystal templating method, periodically ordered macroporous architectures with controllable dual porosity are fabricated (see picture). Taking BiVO4 as an example, these unique structures provide a platform for a better understanding of the correlation between material geometrical features and charge migration for the photoelectrochemical water splitting process. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yin F.,Anhui University of Science and Technology | Wang Z.,Anhui University of Science and Technology | Li Z.,CAS Shanghai Institute of Organic Chemistry | Li C.,CAS Shanghai Institute of Organic Chemistry | Li C.,Anhui University of Science and Technology
Journal of the American Chemical Society | Year: 2012

Although fluorinated compounds have found widespread applications in the chemical and materials industries, general and site-specific C(sp 3)-F bond formations are still a challenging task. We report here that with the catalysis of AgNO 3, various aliphatic carboxylic acids undergo efficient decarboxylative fluorination with SELECTFLUOR® reagent in aqueous solution, leading to the synthesis of the corresponding alkyl fluorides in satisfactory yields under mild conditions. This radical fluorination method is not only efficient and general but also chemoselective and functional-group- compatible, thus making it highly practical in the synthesis of fluorinated molecules. A mechanism involvinig Ag(III)-mediated single electron transfer followed by fluorine atom transfer is proposed for this catalytic fluorodecarboxylation. © 2012 American Chemical Society.

Feng C.,Anhui University of Science and Technology | Loh T.-P.,Anhui University of Science and Technology | Loh T.-P.,Nanyang Technological University
Angewandte Chemie - International Edition | Year: 2013

Assistance provided: The directing group in the title reaction not only activates the substrates but also allows the stereospecific formation of cis-trifluoromethylated products. The reaction is operationally simple and tolerates a wide variety of functional groups, thus providing an efficient method for the stereoselective synthesis of β-CF3-functionalized acrylamide derivatives. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yang F.-L.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Angewandte Chemie - International Edition | Year: 2013

New S in town: Sulfonyl hydrazides smoothly undergo sulfenylation with indoles in the presence of 10 mol % I2 to give structurally diverse indole thioethers in moderate to excellent yields with extremely high regioselectivity. This study paves the way for the use of sulfonyl hydrazides as unique sulfur electrophiles in chemical synthesis. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wu H.-B.,Anhui University of Science and Technology | Ma X.-T.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Chemical Communications | Year: 2014

In the presence of 2.5 mol% Pd2(dba)3-TMEDA (1 : 4), a range of enantioenriched allylic alcohols smoothly coupled with boronic acids in a highly regioselective fashion with inversion of configuration to afford structurally diverse alkenes in good yields with perfect retention of ee. © 2014 The Royal Society of Chemistry.

Yang X.-F.,Nanyang Technological University | Hu X.-H.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology | Loh T.-P.,Nanyang Technological University
Organic Letters | Year: 2015

A Rh-catalyzed redox-neutral C-H functionalization of N-carbamoyl indolines with various internal alkynes has been developed. The reaction, which involves the sequential cleavage of the C-H bond of the indoline at the C7-position and the C-N bond of the urea motif, provides a divergent protocol to rapidly assemble fused-ring pyrroloquinolinone analogues by using a direct alkenylation/annulation strategy with high efficiency and selectivity. © 2015 American Chemical Society.

Li Y.,CAS Shanghai Institute of Organic Chemistry | Li Y.,Anhui University of Science and Technology | Sun J.,CAS Shanghai Institute of Organic Chemistry | Yu B.,CAS Shanghai Institute of Organic Chemistry
Organic Letters | Year: 2011

Glycosylation of the acid labile betulin and betulinic acid derivatives was achieved with glycosyl ortho-hexynylbenzoates as donors under the catalysis of PPh 3AuNTf 2; this enabled the efficient synthesis of lupane-type saponins, as exemplified by the total synthesis of the proposed betulinic acid trisaccharide from Bersama engleriana. © 2011 American Chemical Society.

Tang Y.,CAS Shanghai Institute of Organic Chemistry | Li J.,Anhui University of Science and Technology | Zhu Y.,CAS Shanghai Institute of Organic Chemistry | Li Y.,CAS Shanghai Institute of Organic Chemistry | Yu B.,CAS Shanghai Institute of Organic Chemistry
Journal of the American Chemical Society | Year: 2013

Anomerization, which involves cleavage and formation of the anomeric C-O bond, is of fundamental importance in the carbohydrate chemistry. Herein, the unexpected gold(I)-catalyzed anomerization of glycosyl ortho-alkynylbenzoates has been studied in detail. Especially, crossover experiments in the presence of an exogenous isochromen-4-yl gold(I) complex confirm that the anomerization proceeds via the exocleavage mechanism, involving (surprisingly) the addition of the isochromen-4-yl gold(I) complex onto a sugar oxocarbenium (or dioxolenium) and an elimination of LAu+ from the vinyl gold(I) complex. The inhibitory effect of the exogenous isochromen-4-yl gold(I) complex when in stoichiometric amount on the anomerization has guided us to disclose an isochromen-4-yl gem-gold(I) complex, which is inactive in catalysis but in equilibrium with the monogold(I) complex and the LAu+ catalyst. The proposed key intermediate in the anomerization, a transient glycosyloxypyrylium species, is successfully trapped via a cycloaddition reaction with n-butyl vinyl ether as a dienophile. SN2-like substitution of the initially formed glycosyloxypyrylium intermediate has then been achieved to a large extent via charging with acceptors in an excess amount to lead to the corresponding glycosides in a stereoselective manner. © 2013 American Chemical Society.

Ding G.-J.,Anhui University of Science and Technology | Zhou Y.-L.,CAS Institute of High Energy Physics
Journal of High Energy Physics | Year: 2014

We provide a systematic and thorough exploration of the Δ(48) family symmetry and the consistent generalised CP symmetry. A model-independent analysis of the achievable lepton flavor mixing is performed by considering all the possible remnant symmetries in the neutrino and the charged lepton sectors. We find a new interesting mixing pattern in which both lepton mixing angles and CP phases are nontrivial functions of a single parameter θ. The value of θ can be fixed by the measured reactor mixing angle θ 13, and the excellent agreement with the present data can be achieved. A supersymmetric model based on Δ(48) family symmetry and generalised CP symmetry is constructed, and this new mixing pattern is exactly reproduced. © 2014 The Author(s).

Zhou M.,Anhui University of Science and Technology | Lou X.W.,Nanyang Technological University | Xie Y.,Anhui University of Science and Technology
Nano Today | Year: 2013

In view of the worldwide energy challenge in the 21st century, the technology of semiconductor-based photoelectrochemical (PEC) water splitting has received considerable attention as an alternative approach for solar energy harvesting and storage. The performance of advanced PEC devices is fundamentally related to the semiconductor photoelectrode design at the nanoscale. Among various architectures, two-dimensional (2D) nanosheets with thickness generally below 100 nm hold great promise for highly efficient PEC water splitting. Hence, this article mainly provides a comprehensive review of current research efforts that focus on the scientific and technological possibilities of using 2D nanosheets to fabricate efficient photoelectrodes for PEC water splitting, followed by a concise overview of the state-of-the-art progress of 2D nanosheets, where we also present a discussion of how to overcome the challenges that have prevented realizing the full potential of 2D nanosheets. Particular attention is paid on two major approaches. One is to align nanosheets directly on the substrate to maximize the morphological advantages of 2D nanosheets. The other is to further reduce the thickness of common 2D nanosheets to single or a few atomic layers aiming at regulating the intrinsic physical and chemical properties for PEC water splitting. Both of the approaches have led to excellent improvements on PEC performance and greatly broaden the knowledge about where and how the existing semiconductor materials can be used in solar energy-related applications. It is hence envisioned that 2D nanosheets can offer wide opportunities and perspectives on the directions toward high-efficiency solar energy conversion. © 2013 Elsevier Ltd.

Feng C.,Nanyang Technological University | Feng D.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Chemical Communications | Year: 2015

Rhodium-catalyzed C-H allylation of acrylamides with allyl acetates is reported. The use of weakly coordinating directing group resulted in high reaction efficiency, broad functionality tolerance and excellent γ-selectivity, which opens a new synthetic pathway for the access of 1,4-diene skeletons. © 2015 The Royal Society of Chemistry.

Yang X.-F.,Nanyang Technological University | Hu X.-H.,Nanyang Technological University | Feng C.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Chemical Communications | Year: 2015

A Rh(iii)-catalyzed regioselective C-H alkenylation and alkynylation of indolines is described. This protocol relies on the use of a removable pyridinyl directing group to access valuable C-7 functionalized indoline scaffolds with ample substrate scope and broad functional group tolerance. This journal is © The Royal Society of Chemistry.

Cheng J.-K.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology | Loh T.-P.,Nanyang Technological University
Journal of the American Chemical Society | Year: 2015

A zerovalent copper- and cobalt-catalyzed direct coupling of the sp3 α-carbon of alcohols with alkenes and hydroperoxides was developed in which the hydroperoxides acted as radical initiator and then coupling partner. 1,3-Enynes and vinylarenes underwent alkylation-peroxidation to give β-peroxy alcohols and β-hydroxyketones correspondingly with excellent functional group tolerance. The resulting β-peroxy alcohols could be further transformed into β-hydroxyynones and propargylic 1,3-diols. © 2014 American Chemical Society.

Zhao Y.,Nanyang Technological University | Luo Z.,Nanyang Technological University | Li M.,Nanyang Technological University | Qu Q.,Nanyang Technological University | And 2 more authors.
Angewandte Chemie - International Edition | Year: 2015

Biomedical applications of nontoxic amorphous calcium carbonate (ACC) nanoparticles have mainly been restricted because of their aqueous instability. To improve their stability in physiological environments while retaining their pH-responsiveness, a novel nanoreactor of ACC-doxorubicin (DOX)@silica was developed for drug delivery for use in cancer therapy. As a result of its rationally engineered structure, this nanoreactor maintains a low drug leakage in physiological and lysosomal/endosomal environments, and responds specifically to pH 6.5 to release the drug. This unique ACC-DOX@silica nanoreactor releases DOX precisely in the weakly acidic microenvironment of cancer cells and results in efficient cell death, thus showing its great potential as a desirable chemotherapeutic nanosystem for cancer therapy. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA.

Gu Y.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Synlett | Year: 2013

The cleavage of the sp3 carbon-nitrogen bonds in N-alkylsulfonamides has been utilized for the selective formation of various carbon-carbon and carbon-heteroatom bonds. When N-alkylsulfonamides undergo sp3 carbon-nitrogen bond cleavage in the presence of acid catalysts, the resulting carbocations can react with a broad range of carbon, sulfur, nitrogen, oxygen, or hydride nucleophiles. On the other hand, basic conditions allow N-alkylsulfonamides to act as sp3 carbon electrophiles in reactions with strong nucleophiles. In general, N-benzylic, N-allylic, and N-propargylic sulfonamides serve as suitable substrates, and their reactions with nucleophiles provide ready access to a wide range of functionalized molecules. 1 Introduction 2 Mechanism 3 Reactions with Carbon Nucleophiles 3.1 Active Methylene Compounds 3.2 Ketones and Aldehydes 3.3 Aromatic Compounds 3.4 Alkynes, Alkenes, and Arylallenes 3.5 Silylated Carbon Nucleophiles 3.6 Grignard Reagents 4 Reactions with Sulfur Nucleophiles 4.1 Thiols and Thiophenols 4.2 Thioacetic acid 4.3 Sulfinic Acids 5 Reactions with Nitrogen Nucleophiles 6 Reactions with Oxygen Nucleophiles 7 Reduction 8 Conclusion © Georg Thieme Verlag Stuttgart New York.

Feng C.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Chemical Science | Year: 2012

Copper-catalyzed olefinic trifluoromethylation and oxytrifluoromethylation of enamides is reported. The direct olefinic C-H trifluoromethylation constitutes an efficient method for the stereoselective synthesis of β-trifluoromethyl substituted enamides. © 2012 The Royal Society of Chemistry.

Yang F.-L.,Anhui University of Science and Technology | Ma X.-T.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Chemistry - A European Journal | Year: 2012

A useful source: Arylsulfonyl hydrazides have been identified as synthetically useful aryl sources for the Pd(OAc) 2 catalyzed oxidative Mizoroki-Heck-type reaction under molecular oxygen to provide a convenient access to polysubstituted alkenes in a highly regio- and stereoselective manner (see scheme). The reaction well tolerates various functional groups such as alkoxy, halo, alcohol, carboxylic acid, ester, amide, sulfonamide, and sulfone. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang G.-W.,Anhui University of Science and Technology | Wang C.-Z.,Anhui University of Science and Technology | Zhu S.-E.,Anhui University of Science and Technology | Murata Y.,Kyoto University
Chemical Communications | Year: 2011

Radical reaction of [60]fullerene with phosphonate esters mediated by manganese(iii) acetate in chlorobenzene afforded singly-bonded fullerene dimers, of which the individual meso and racemic isomers could be unexpectedly separated out for the first time. © 2011 The Royal Society of Chemistry.

Li Y.F.,CAS Institute of High Energy Physics | Liu S.-S.,Anhui University of Science and Technology
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2012

Light sterile neutrinos with masses at the sub-eV or eV scale are hinted by current experimental and cosmological data. Assuming the Majorana nature of these hypothetical particles, we discuss their effects in the neutrinoless double beta decay by exploring the implications of a vanishing effective Majorana neutrino mass 〈m〉ee. Allowed ranges of neutrino masses, mixing angles and Majorana CP-violating phases are illustrated in some instructive cases for both normal and inverted mass hierarchies of three active neutrinos. © 2011 Elsevier B.V.

Feng C.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Angewandte Chemie - International Edition | Year: 2014

The rhodium(III)-catalyzed ortho C-H alkynylation of non-electronically activated arenes is disclosed. This process features a straightforward and highly effective protocol for the synthesis of functionalized alkynes and represents the first example of merging a hypervalent iodine reagent with rhodium(III) catalysis. Notably, this reaction proceeds at room temperature, tolerates a variety of functional groups, and more importantly, exhibits high selectivity for monoalkynylation. Hot rhod: A rhodium-catalyzed, electronically reversed Sonogashira reaction between unbiased arenes and the hypervalent iodine reagent 1 proceeds through C-H activation. This reaction displays excellent functional-group tolerance and high efficiency, and thus opens a new synthetic pathway to access functionalized alkynes. Cp*=C5Me5, DCE=1,2-dichloroethane, Piv=pivaloyl, TIPS=triisopropylsilyl. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Abbas A.,Nanyang Technological University | Xing B.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology | Loh T.-P.,Nanyang Technological University
Angewandte Chemie - International Edition | Year: 2014

In this study, a remarkably simple and direct strategy has been successfully developed to selectively label target cysteine residues in fully unprotected peptides and proteins. The strategy is based on the reaction between allenamides and the cysteine thiol, and proceeds swiftly in aqueous medium with excellent selectivity and quantitative conversion, thus forming a stable and irreversible conjugate. The combined simplicity and mildness of the process project allenamide as robust and versatile handles to target cysteines and has potential use in biological systems. Additionally, fluorescent-labeling studies demonstrated that the installation of a C-terminal allenamide moiety onto various molecules of interest may supply a new methodology towards the site-specific labeling of cysteine-containing proteins. Such a new labeling strategy may thus open a window for its application in the field of life sciences. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yang F.-L.,Anhui University of Science and Technology | Wang F.-X.,Anhui University of Science and Technology | Wang T.-T.,Anhui University of Science and Technology | Wang Y.-J.,Anhui University of Science and Technology | And 2 more authors.
Chemical Communications | Year: 2014

An unprecedented three-component oxysulfenylation reaction of alkenes with sulfonyl hydrazides and alcohols has been developed in the presence of 20 mol% iodine to give a range of structurally diverse β-alkoxy sulfides in good to excellent yields. This journal is © The Royal Society of Chemistry.

Zhu M.-K.,Nanyang Technological University | Chen Y.-C.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology | Loh T.-P.,Nanyang Technological University
Chemistry - A European Journal | Year: 2013

Metal-free synthesis: Diamination of alkenes by using phenylhydrazine and azodicarboxylates could be achieved in a one-pot manner under very mild conditions (see scheme; Boc=tert-butoxycarbonyl). This process works with the assistance of acetic acid by means of a radical mechanism and displays a high trans selectivity when cycloalkene substrates were used in the reaction. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Wang Z.,Anhui University of Science and Technology | Zhu L.,Anhui University of Science and Technology | Yin F.,Anhui University of Science and Technology | Su Z.,CAS Shanghai Institute of Organic Chemistry | And 3 more authors.
Journal of the American Chemical Society | Year: 2012

Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen) 2OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation. © 2012 American Chemical Society.

Zhang J.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Chemical Communications | Year: 2012

Ruthenium- and rhodium-catalyzed direct oxidative cross-coupling reactions of acrylamides with alkenes were developed. These methods provide an efficient route for the synthesis of (Z,E)-dienamides in excellent yields with good stereoselectivity. The catalytic systems allowed oxidative olefination of a wide range of alkenes bearing different functional groups, such as CO2R, COMe, SO2Ph, aryl, CONHBn, CN, PO(OEt)2, as well as Weinreb amide. © 2012 The Royal Society of Chemistry.

Shao Y.-D.,Anhui University of Science and Technology | Tian S.-K.,Anhui University of Science and Technology | Tian S.-K.,CAS Shanghai Institute of Organic Chemistry
Chemical Communications | Year: 2012

A range of 3H-indoles and 2H-benzo[b][1,4]thiazines smoothly undergo asymmetric Strecker reaction with ethyl cyanoformate in the presence of a Cinchona alkaloid-based thiourea catalyst at 10 °C to give structurally diverse nitrogen-containing heterocycles in good to excellent yields and with excellent ee. © 2012 The Royal Society of Chemistry.

Hu X.-H.,Nanyang Technological University | Zhang J.,Nanyang Technological University | Yang X.-F.,Nanyang Technological University | Xu Y.-H.,Anhui University of Science and Technology | And 2 more authors.
Journal of the American Chemical Society | Year: 2015

A Ru-catalyzed direct oxidative cross-coupling reaction of acrylates was developed. It offers a straightforward and atom-economical protocol for the synthesis of functionalized (Z,E)-muconate derivatives in moderate to good yields with good stereo- and chemoselectivities. The conjugated muconates bearing differentiable terminal functionality can be selectively transformed into versatile synthetic intermediates widely used in organic synthesis. © 2015 American Chemical Society.

Feng C.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Organic Letters | Year: 2014

Rh(III)-catalyzed umpolung amidation of alkenylboronic acids for the synthesis of enamides is reported. This reaction proceeds readily at room temperature and displays an extremely wide spectrum of functional group tolerance. With cooperation of hydroboration, it enables the formal anti-Markovnikov hydroamidation of terminal alkynes, stereospecifically affording the trans-enamides in excellent yields. © 2014 American Chemical Society.

Feng C.,Nanyang Technological University | Feng D.,Nanyang Technological University | Luo Y.,Nanyang Technological University | Loh T.-P.,Nanyang Technological University | Loh T.-P.,Anhui University of Science and Technology
Organic Letters | Year: 2014

The Rh(III)-catalyzed C-H alkynylation of acrylamide derivative is realized using a hypervalent alkynyl iodine reagent. The use of a weakly coordinating directing group proved to be of critical importance. This reaction displays broad functional group tolerance and high efficiency, which opens a new synthetic pathway to access functionalized 1,3-enyne skeletons. © 2014 American Chemical Society.

Petek H.,University of Pittsburgh | Zhao J.,Anhui University of Science and Technology
Chemical Reviews | Year: 2010

In this review we have described recent experimental and theoretical research on ultrafast interfacial inner sphere PCET dynamics. What makes interfacial PCET processes unique is the presence of a strong potential gradient that imposes opposing forces on electrons and protons within a spatial region that is, at most, a few angstroms wide. Because of the strong but tunable gradients, whether a PCET process occurs through separate proton and electron transfer steps or through a concerted process can have a significant impact on the activation energies and overpotentials that are required for a chemical reaction. Considering that tantalizing photocatalytic processes, such as the decomposition of H2O into H2 and O2 and the reduction of CO2 into chemical fuels,11,154,155 have been demonstrated with band gap excitation of TiO2 surfaces, it is highly desirable to explore the reaction mechanisms and to devise chemical pathways that perform the multiple electron and proton transfer steps as close to the thermodynamic limit as possible. In addition to the complexity of describing chemical processes under strongly inhomogeneous potentials, it is also necessary to devise experimental methods that can probe ultrafast charge transfer processes at interfaces. Techniques such as time-resolved two-photon photoemission provide the means to probe interfacial charge transfer dynamics on time scales that range from a few femtoseconds to longer. The recently developed attosecond laser technology is promising for time resolving even faster processes,156 as attested by measurements of electron transport through a metal interface. 157 Electron spectroscopic methods, however, are limited to well-defined surfaces under UHV conditions where photoelectron energy and momentum can be related simply to the properties of the excited states of the system. It is also desirable to develop and employ other methods, such as X-ray scattering and surface nonlinear spectroscopy,46,158,159 which can provide chemical and dynamical contrast under more realistic chemical reaction conditions. Ultrafast interfacial PCET also presents substantial challenges for theory. In addition to the difficulty of describing the interfacial potential and, associated with it, the inhomogeneous screening by the fast and slow degrees of freedom of the system, it is also a challenge to treat the electron and proton degrees of freedom on an equal basis, as described elsewhere in this Special Issue.4 This is the case for PCET processes occurring under near equilibrium conditions, but challenges are particularly severe for excited state processes, such as would predominate under photocatalytic conditions. Nevertheless, several groups are paving the way to develop methods that are starting to provide valuable insights and powerful tools for investigating ultrafast interfacial PCET dynamics in photon mediated processes.118,134,138 The challenges are severe, but the rewards for learning how to harness PCET processes in photocatalysis based clean energy generation make the effort essential. © 2010 American Chemical Society.

Chow S.-N.,Georgia Institute of Technology | Huang W.,Anhui University of Science and Technology | Li Y.,Georgia Institute of Technology | Zhou H.,Georgia Institute of Technology
Archive for Rational Mechanics and Analysis | Year: 2012

The classical Fokker-Planck equation is a linear parabolic equation which describes the time evolution of the probability distribution of a stochastic process defined on a Euclidean space. Corresponding to a stochastic process, there often exists a free energy functional which is defined on the space of probability distributions and is a linear combination of a potential and an entropy. In recent years, it has been shown that the Fokker-Planck equation is the gradient flow of the free energy functional defined on the Riemannian manifold of probability distributions whose inner product is generated by a 2-Wasserstein distance. In this paper, we consider analogous matters for a free energy functional or Markov process defined on a graph with a finite number of vertices and edges. If N ≧ 2 is the number of vertices of the graph, we show that the corresponding Fokker-Planck equation is a system of Nnonlinear ordinary differential equations defined on a Riemannian manifold of probability distributions. However, in contrast to stochastic processes defined on Euclidean spaces, the situation is more subtle for discrete spaces. We have different choices for inner products on the space of probability distributions resulting in different Fokker-Planck equations for the same process. It is shown that there is a strong connection but there are also substantial discrepancies between the systems of ordinary differential equations and the classical Fokker-Planck equation on Euclidean spaces. Furthermore, both systems of ordinary differential equations are gradient flows for the same free energy functional defined on the Riemannian manifolds of probability distributions with different metrics. Some examples are also discussed. © 2011 Springer-Verlag.

Wang J.-R.,CAS Hefei Institutes of Physical Science | Liu G.-Z.,Anhui University of Science and Technology | Zhang C.-J.,CAS Hefei Institutes of Physical Science
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

Extensive investigations show that QED3 exhibits dynamical fermion mass generation at zero temperature when the fermion flavor N is sufficiently small. However, it seems difficult to extend the theoretical analysis to finite temperature. We study this problem by means of the Dyson-Schwinger equation approach after considering the effect of finite temperature or disorder-induced fermion damping. Under the widely used instantaneous approximation, the dynamical mass displays an infrared divergence in both cases. We then adopt a new approximation that includes an energy-dependent gauge boson propagator and obtain results for dynamical fermion mass that do not contain infrared divergence. The validity of the new approximation is examined by comparing it to the well-established results obtained at zero temperature. © 2015 American Physical Society.

Xia X.,Emory University | Zeng J.,Anhui University of Science and Technology | Zhang Q.,East China Normal University | Moran C.H.,Emory University | Xia Y.,Emory University
Journal of Physical Chemistry C | Year: 2012

This feature article introduces our recent work on understanding the roles played by citrate and poly(vinyl pyrrolidone) (PVP) as capping agents in seed-mediated syntheses of Ag nanocrystals with controlled shapes. We have demonstrated that citrate and PVP selectively bind to Ag(111) and Ag(100) surfaces, respectively, and thus favor the formation of Ag nanocrystals enclosed preferentially by {111} or {100} facets. In addition, we have quantified the coverage density of PVP adsorbed on the surface of Ag nanocubes. On the basis of the mechanistic understanding, a series of Ag nanocrystals with controlled shapes and sizes have been successfully synthesized by using different combinations of seeds and capping agents: single-crystal spherical/cubic seeds with citrate for cuboctahedrons and octahedrons or with PVP for cubes and bars and plate-like seeds with citrate for enlarged thin plates or with PVP for thickened plates. © 2012 American Chemical Society.

Yao C.,CAS Hefei Institutes of Physical Science | Chen J.,CAS Hefei Institutes of Physical Science | Chen J.,Anhui University of Science and Technology | Li M.-B.,CAS Hefei Institutes of Physical Science | And 3 more authors.
Nano Letters | Year: 2015

Alloy nanoparticles with atomic monodispersity is of importance for some fundamental research (e.g., the investigation of active sites). However, the controlled preparation of alloy nanoparticles with atomic monodispersity has long been a major challenge. Herein, for the first time a unique method, antigalvanic reduction (AGR), is introduced to synthesize atomically monodisperse Au25Ag2(SC2H4Ph)18 in high yield (89%) within 2 min. Interestingly, the two silver atoms in Au25Ag2(SC2H4Ph)18 do not replace the gold atoms in the precursor particle Au25(SC2H4Ph)18 but collocate on Au25, which was supported by experimental and calculated results. Also, the two silver atoms are active to play roles in stabilizing the alloy nanoparticle, triggering the nanoparticle fluorescence and catalyzing the hydrolysis of 1,3-diphenylprop-2-ynyl acetate. © 2015 American Chemical Society.

Nie Y.,Anhui University of Science and Technology | Liu X.,Anhui University of Science and Technology | Emslie S.D.,University of North Carolina at Wilmington
Microchemical Journal | Year: 2014

Concentrations of rare earth elements (REEs) were determined in three ornithogenic sediment profiles excavated at active Adélie penguin (Pygoscelis adeliae) colonies in McMurdo Sound, Ross Sea, Antarctica. The distribution of REEs in each profile fluctuated with depth. REEs measured in environmental media (including bedrock, guano, and algae) and analysis on the correlations of σREE-lithological elements and σREE-bio-elements in the profiles indicated that sedimentary REEs were mainly from weathered bedrock in this area, and the non-crustal bio-genetic REEs from guano and algae were minor. Further discussion on the slopes and Ce and Eu anomalies of chondrite-normalized REE patterns indicated that a mixing process of weathered bedrock, guano and algae was the main controlling factor for the fluctuations of REEs with depth in the sediments. An end-member equation was developed to calculate the proportion of REEs from the three constituents in the sediments. The calculation functioned well in estimating bedrock-derived REEs and the magnitude of ornithogenic influence in different profiles. In general, REEs in the ornithogenic sediments showed anti bio-element patterns and thus can be used as an additional proxy to reconstruct historical penguin populations. © 2014 Elsevier B.V.

Liu X.,Anhui University of Science and Technology | Nie Y.,Anhui University of Science and Technology | Sun L.,Anhui University of Science and Technology | Emslie S.D.,University of North Carolina at Wilmington
Geochimica et Cosmochimica Acta | Year: 2013

Seabirds have substantial influence on geochemical circulation of elements, serving as a link for substance exchange between their foraging area and colonies. In this study, we investigated the elemental and carbon isotopic composition of five penguin-affected sediment profiles excavated from Ross Island and Beaufort Island in the Ross Sea region, Antarctica. Among the three main constituents of the sediments (including weathered bedrock, guano and algae), guano was the main source of organic matter and nutrients, causing selective enrichment of several elements in each of the sediment profiles. In the 22 measured elements, As, Cd, Cu, P, S, Se and Zn were identified as penguin bio-elements in the Ross Sea region through statistical analysis and comparison with local end-member environmental media such as weathered bedrock, fresh guano and fresh algae. Carbon isotopic composition in the ornithogenic sediments showed a mixing feature of guano and algae. Using a two-member isotope mixing equation, we were able to reconstruct the historical change of guano input and algal bio-mass. Compared with research in other parts of Antarctic, Arctic, and South China Sea, we found apparent overlap of avian bio-elements including As, Cd, Cu, P, Se, and Zn. Information on the composition and behavior of bio-elements in seabird guano on a global scale, and the role that bio-vectors play in the geochemical circulation between land and sea, will facilitate future research on avian ecology and paleoclimatic reconstruction. © 2013 Elsevier Ltd.

Nie Y.,Anhui University of Science and Technology | Liu X.,Anhui University of Science and Technology | Sun L.,Anhui University of Science and Technology | Emslie S.D.,University of North Carolina at Wilmington
Science of the Total Environment | Year: 2012

Total mercury (Hg) concentration and several other geochemical parameters were determined for five sediment profiles from the Antarctic Ross Sea region. Our data exhibit significant positive correlations between Hg concentration and total organic carbon (TOC) content in all profiles, suggesting the predominant role of organic matter (OM) as a Hg carrier. The OM in the sediments originates primarily from penguin guano and algae. High Hg content in guano and a positive correlation between Hg and a guano bio-element (phosphorus, P) in the ornithogenic sediment profiles (MB6, BI and CC) indicate that Hg was strongly influenced by guano input. The bottom sediments of MB6 with seal hairs contain relatively high Hg. This increase is attributed to the input of seal excrement, suggesting that sedimentary Hg may be an effective trophic-level indicator from seals to penguins. The enrichment factor (EF) for Hg was calculated and the results indicated apparent Hg enrichment in the sediment profiles from the Ross Sea region caused by bio-vectors such as penguins and seals. Compared with typical sediments from other sites in Antarctica and the SQGs (sediment quality guidelines), the total amount of Hg in our study area is still not considered to be adversely high. © 2012 Elsevier B.V.

Cheng Y.,East China Normal University | Zhao L.,Anhui University of Science and Technology | Li Y.,University of Akron | Xu T.,Anhui University of Science and Technology
Chemical Society Reviews | Year: 2011

In the past decade, nanomedicine with its promise of improved therapy and diagnostics has revolutionized conventional health care and medical technology. Dendrimers and dendrimer-based therapeutics are outstanding candidates in this exciting field as more and more biological systems have benefited from these starburst molecules. Anticancer agents can be either encapsulated in or conjugated to dendrimer and be delivered to the tumour via enhanced permeability and retention (EPR) effect of the nanoparticle and/or with the help of a targeting moiety such as antibody, peptides, vitamins, and hormones. Imaging agents including MRI contrast agents, radionuclide probes, computed tomography contrast agents, and fluorescent dyes are combined with the multifunctional nanomedicine for targeted therapy with simultaneous cancer diagnosis. However, an important question reported with dendrimer-based therapeutics as well as other nanomedicines to date is the long-term viability and biocompatibility of the nanotherapeutics. This critical review focuses on the design of biocompatible dendrimers for cancer diagnosis and therapy. The biocompatibility aspects of dendrimers such as nanotoxicity, long-term circulation, and degradation are discussed. The construction of novel dendrimers with biocompatible components, and the surface modification of commercially available dendrimers by PEGylation, acetylation, glycosylation, and amino acid functionalization have been proposed as available strategies to solve the safety problem of dendrimer-based nanotherapeutics. Also, exciting opportunities and challenges on the development of dendrimer-based nanoplatforms for targeted cancer diagnosis and therapy are reviewed (404 references). © 2011 The Royal Society of Chemistry.

Xu Y.,Anhui University of Science and Technology | Du J.,Anhui University of Science and Technology | Dai L.-R.,Anhui University of Science and Technology | Lee C.-H.,Georgia Institute of Technology
IEEE Signal Processing Letters | Year: 2014

This letter presents a regression-based speech enhancement framework using deep neural networks (DNNs) with a multiple-layer deep architecture. In the DNN learning process, a large training set ensures a powerful modeling capability to estimate the complicated nonlinear mapping from observed noisy speech to desired clean signals. Acoustic context was found to improve the continuity of speech to be separated from the background noises successfully without the annoying musical artifact commonly observed in conventional speech enhancement algorithms. A series of pilot experiments were conducted under multi-condition training with more than 100 hours of simulated speech data, resulting in a good generalization capability even in mismatched testing conditions. When compared with the logarithmic minimum mean square error approach, the proposed DNN-based algorithm tends to achieve significant improvements in terms of various objective quality measures. Furthermore, in a subjective preference evaluation with 10 listeners, 76.35% of the subjects were found to prefer DNN-based enhanced speech to that obtained with other conventional technique. © 1994-2012 IEEE.

Zheng Y.,Georgia Institute of Technology | Zeng J.,Anhui University of Science and Technology | Ruditskiy A.,Georgia Institute of Technology | Liu M.,Georgia Institute of Technology | Xia Y.,Georgia Institute of Technology
Chemistry of Materials | Year: 2014

Oxidative etching plays an important role in the synthesis of metal nanocrystals. This is because the zerovalent species, including atoms, clusters, and nanocrystallites, can all be oxidized back to the ionic form and thus altering the types and distributions of products formed in both the nucleation and growth steps. In the first part of this review, we discuss the critical components needed for oxidative etching, as well as methods for enabling or preventing oxidative etching in a synthesis. We then present and analyze a number of interesting experimental observations caused by oxidative etching. In the following sections, we highlight four major applications of oxidative etching in the synthesis of metal nanocrystals, with regards to experimental controls over the crystallinity, size, shape, morphology, and growth kinetics. © 2013 American Chemical Society.

Hu J.,Anhui University of Science and Technology | Xu T.,Anhui University of Science and Technology | Cheng Y.,East China Normal University
Chemical Reviews | Year: 2012

Applications of various NMR techniques to investigate the host behaviors of different dendrimers were reviewed. Chemical shift titration experiments give information on the types of interactions between dendrimer and guests, and can be used to calculate the binding parameters of the host-guest systems including number of binding sites and binding affinities. NOE analysis provides precise spatial conformations such as the localizations and orientations of the guests within the dendrimer/guest complexes. Diffusion NMR reveals the size of the dendrimer/guest complexes and can be used to predict the supramolecular structure of the dendrimer/surfactant aggregates. Relaxation measurement reflects the mobility and rigidity of the guest molecules bound with dendrimers. Besides, the combination of NOE, diffusion, and STD NMR experiments is successfully used for high-throughput screening dendrimer-binding drugs. NMR techniques also provide precise size information of palladium nanoparticles loaded within dendrimers.

Wu Y.,CAS Hefei Institutes of Physical Science | Wu Y.,Anhui University of Science and Technology
Fusion Engineering and Design | Year: 2011

China focuses on the development of the liquid LiPb blanket due to its attractive performances. A series of LiPb breeder blanket concepts were proposed for different applications of fusion in China. This paper gives an overview of the LiPb breeder blanket concepts and relevant R&D progress in China. © 2011 Published by Elsevier B.V.

Li W.-Y.,Anhui University of Science and Technology | Li W.-Y.,University of Arkansas | Teng F.-Z.,University of Arkansas | Xiao Y.,Anhui University of Science and Technology | Huang J.,Anhui University of Science and Technology
Earth and Planetary Science Letters | Year: 2011

To investigate the magnitude and mechanism of inter-mineral Mg isotope fractionation at high temperatures, we report high-precision analyses of Mg isotopes for 10 whole rocks and 13 mineral separates for a set of eclogites from Bixiling in the Dabie orogen, China. Magnesium isotopic compositions of whole rocks (δ26Mg of -0.44 to-0.26%) are similar to the estimated δ26Mg values of the mantle, suggesting Mg isotopic inheritance from a gabbroic protolith with limited Mg isotope fractionation during eclogite-facies metamorphism. By contrast, mineral separates are highly heterogeneous, with δ26Mg values ranging from +0.30 to +0.60% in phengite, from +0.16 to +0.40% in omphacite and from -0.95 to -0.74% in garnet. Phengite and omphacite are >1% heavier in δ26Mg than coexisting garnet, indicating large high-temperature inter-mineral Mg isotope fractionations. The constant δ26Mgomphacite-garnet (=Δ26Mgomphacite=Δ26Mggarnet) value (1.14±0.04%), together with homogeneous mineral chemistry and equilibrium oxygen isotopic partitioning between omphacite and garnet, suggests an equilibrium Mg isotope fractionation, controlled by the difference in coordination number of Mg between omphacite (six) and garnet (eight). The 1.14% fractionation is the largest high-temperature equilibrium inter-mineral Mg isotope fractionation observed so far and makes the omphacite-garnet Mg isotope fractionation a potential geothermometer. By contrast, Mg isotope fractionations between phengite and garnet and between phengite and omphacite vary from 1.25 to 1.47% and from 0.14 to 0.32%, respectively. This implies Mg isotopic disequilibria between phengite and garnet/omphacite, which might result from the Mg isotopic variation in phengites due to Mg isotope exchange between phengites and retrograde fluids in Bixiling eclogites. © 2011 Elsevier B.V.