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Synthesis and performance of Li_4Ti_5O_(12) anode materials using the PVP-assisted combustion method

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Chinese Chemical Letters 2014年第12期25卷 1569-1572页

作者： Long-Jiao Chang Shao-Hua Luo hai-Liang Zhang xi-Wei Qi Zhi-Yuan Wang Yan-Guo Liu Yu-chun Zhai School of Materials and Metallurgy Northeastern University Hebei Provincial Laboratory of Dielectric and Electrolyte Functionals Materials School of Resources and Materials Northeastern University at Qinghuangdao Branch

Li4Ti5O12 was synthesized by a facile gel-combustion method（GCM） with polyvinylpyrrolidone（PVP） as the polymer chelating agent and *** structural and electrochemical properties of the sample were compared with the one prepared by the conventional solid-state reaction（SSR） through X-ray diffraction（XRD）,scanning electron microscopy（SEM）,cyclic voltammetry（CV）,charge-discharge measurements,and electrochemical impedance spectroscopy（EIS）,*** sub-microscale Li4Ti5O12 oxides,with a high phase purity and good stoichiometry,can be obtained by annealing at 800℃.The grain size is smaller than that of the samples that were power prepared by ***-ion batteries with a GCM Li4Ti5O12 anode exhibit excellent reversible capacities of 167.6,160.7,152.9,and 144.2 mAh/g,at the current densities of 0.5 C,1 C,3 C and 5 C,*** excellent cycling and rate performance can be attributed to the smaller particle size,lower charge-transfer resistance and larger lithium ion diffusion *** is therefore concluded that GCM Li4Ti5O12 is a promising candidate for applications in highrate lithium ion batteries.

关键词： Lithium ion battery Lithium titanate Combustion synthesis Polyvinylpyrrolidone

Dynamical phase transitions in a two-species bosonic Josephson junction

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Frontiers of physics 2017年第5期12卷 151-158页

作者： Jing Tian Jun Liu hai-Bo Qiu xiao-Qiang xi School of Science Xi'an University of Posts and Telecommunications Xi'an 710121 China

We investigate dynamical phase transitions that are induced by interspecies interaction in a two-species bosonic Josephson junctions （B J J）, based on semi-classical theory. In zero-phase mode, similar to the case of a single-species B J J, we observe the well-known dynamical phase transition from Josephson oscillation to self-trapping, which can be induced by both enhanced repulsive and attractive interspecies interactions. In π phase mode, dynamical phase transitions are even more interesting and counter- intuitive. We characterize a dynamical phase transition with the merging of two separate phase space domains into one, which is induced by increasing repulsive interspecies interaction. On the other hand, we find that by increasing attractive interspecies interaction, a phase separation of two formally overlapped phase space domains will occur. At last, we reveal that these intriguing dynamical phase transitions are caused by different kinds of bifurcations.

关键词： dynamical phase transition bosonic Josephson junction

Differential effects of insecticides on mitochondrial membrane fluidity and ATPase activity between the wolf spider and the rice stem borer

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Journal of Integrative Agriculture 2015年第12期14卷 2574-2580页

作者： LI hai-ping CHANG Jing FENG Tao GAO xi-wu Department of Entomology China Agricultural University College of Agronomy Inner Mongolia Agricultural University College of Life Science Jianghan University

Differential effects of methamidophos and three pyrethroids on ATPase activity and membrane fluidity of mitochondria were investigated between the wolf spider（Pirata subpiraticus（*** Str.））and the rice stem borer（Chilo suppressalis（Walker））.Based on a comparison of LD_（50） values,the toxicities of the tested insecticides were higher to the wolf spider than to the rice stem *** at 1×10^（–4） mmol L^（–1） caused inhibition of the mitochondrial Na~＋-K~＋-ATPase and Ca^（2＋）-Mg^（2＋）-ATPase activities,and it’s inhibitions on Na＋-K＋-ATPase and Ca^（2＋）-Mg^（2＋）-ATPase activities were significantly higher in the wolf spider（44 and 28%）than in the rice stem borer（19 and 11%）.Methamidophos at 1×10^（–4） mmol L^（–1） decreased Ca^（2＋）-Mg^（2＋）-ATPase activity by 16 and 27%in the wolf spider and the rice stem borer,respectively,but no significant effect on the specific activity of Na＋-K＋-ATPase was *** DPH（1,6-diphenyl-1,3,5-hexatriene）fluorescence polarization values of mitochondrial membranes were not significantly affected by methamidophos in either ***,cyhalothrin and alpha-cypermethrin induced the values of DPH polarization of mitochondrial membrane increasing with the concentration of cyhalothrin and alpha-cypermethrin from 20 to 100μmol L^（–1） in the rice stem borer and the wolf *** of ethofenprox on fluidity of the wolf spider and the rice stem borer was *** results suggest that both inhibition of membrane ATPase and changes of membrane fluidity could be appended to the action mechanisms of pyrethroid insecticides.

关键词： pyrethroids membrane fluidity ATPase wolf spider rice stem borer

Quality of service aware admission control in cognitive device-to-device network

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The Journal of China Universities of Posts and Telecommunications 2011年第5期18卷 22-29,36页

作者： FU Zi-xi HU chun-jing PENG Tao LU Qian-xi WANG Wen-bo Wireless Signal Processing and Network Lab Key Laboratory of Universal Wireless Communication Ministry of Education Beijing University of Posts and Telecommunications Beijing 100876 China

A hybrid system of cellular mode and device-to-device （D2D） mode is considered in this paper, where the cellular resource is reused by the D2D transmission. With the objective of capacity maximization, the power optimization of D2D sub-system is considered, taking into account quality of service （QoS） requirement. The power optimization problem is divided into two stages： The first stage is the admission control scheme design based on the QoS requirement of D2D users, and the second is power allocation to maximize aggregate throughput of admissible D2D users. For the D2D admission control problem, a heuristic sorting-based algorithm is proposed to index the admissible D2D links, where gain to Interference ratio （GIR） sorting criterion is used. Applying an approximate form of Shannon capacity, the power allocation problem can be solved by convex optimization and geometric programming tools efficiently. Based on the theoretical analysis, a practical algorithm is proposed. The precision can reach a trade-off between complexity and performance. Numerical simulation results confirm that combining with GIR sorting method, the proposed scheme can significantly improve the D2D system＇s capacity and fairness.

关键词： cognitive radio QoS power control geometric programming sorting-based algorithm

Grain Growth Kinetics of BaTiO3 Nanocrystals During Calcining Process

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Chinese Journal of Chemical Physics 2008年第3期21卷 295-300页

作者： xiao-lan Song xi He hai-ping Yang Yi-xin Qu Guan-zhou Qiu School of Resources Processing and BioenEineerinE Central South University Changsha 410083China College of Chemical Engineering Beijing University of Chemical Technology Beiging 100029China

BaTiO3 nanocrystals were synthesized by sol-gel method using barium acetate （Ba（CH3COO2） and tetrabutyl titanate （Ti（OC4H9）4） as raw materials. Xerogel precursors and products were characterized by means of thermogravimetric/differential scanning calorimetry （TG/DSC）, X-ray diffraction （XRD） and transmission electron microscope （TEM）. The influence of the calcination temperature and duration on the lattice constant, the lattice distortion, and the grain size of BaTiO3 nanocrystals was discussed based on the XRD results. The grain growth kinetics of BaTiO3 nanocrystals during the calcination process were simulated with a conventional grain growth model which only takes into account diffusion, and an isothermal model proposed by Qu and Song, which takes into account both diffusion and surface reactions. Using these models, the pre-exponential factor and the activation energy of the rate constant were estimated. The simulation results indicate that the isothermal model is superior to the conventional one in describing the grain growth process, implying that both diffusion and surface reactions play important roles in the grain growth process.

关键词： BaTiO3 nanocrystal Sol-gel method Grain growth kinetics

Effect of carbon addition on stress rupture properties of a cast TiAl alloy

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Journal of Iron and Steel Research International 2019年第3期26卷 268-274页

作者： xi-wen Zhang Yu-ling Tang chun-lei Zhu Ji Zhang Beijing Key Laboratory of Advanced High Temperature Materials China Iron and Steel Research Institute Group Beijing 100081 China National Center for Electron Microscopy in Beijing School of Materials Science and Engineering Tsinghua University Beijing 100084 China

Two TiAl alloys,Ti^47.5Al-3.7(Cr,V,Zr)and Ti77.5Al-3.7(Cr,V,Zr)-0.1C(at.%),were melted and cast with the same process,*** with strongly oriented lamellae were both observed in these two alloys followed by hot isostatic pressing and heat ***2AlC carbides were identified in the alloy with C *** rupture tests were carried out at 800 and 850°C,with tensile stress from 220 to 400 MPa,*** was shown that the alloy with C experienced much longer lives than the other,especially under the condition of 800°C/260 MPa,800°C/300 MPa,850°C/220 MPa,850°C/240 MPa and 850°C/260 *** of ruptured specimens revealed that the microstructure stability was improved significantly in the alloy with C addition which is attributed to the strengthening effect of Ti-Al-C *** Ti2AlC carbides mainly increased the resistance of dislocation passing through the interfaces and kept the integrity of the *** Ti3AlC carbide was formed during stress rupture process,which could not only effectively act as the barrier of dislocation movement inside the lamellae,but also strengthen the lamellae itself.

关键词： Titanium aluminide Carbon addition Stress rupture property Dynamic precipitated carbide

Na^+/Ca^(2+) Exchange-mediated La^(3+) Entry in Human Lymphocytes

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Chinese Chemical Letters 2001年第9期12卷 815-816页

作者： chun Ying WEI Pin YANG hai Yan WANG Institute of Molecular Science Shanxi UniversityTaiyuan 030006

We determined whether La3+ enter human peripheral blood lymphocytes via Na+/Ca2+ exchanger (measured with fura-2). We first compared the sensitivity of fura-2 with La3+ and Ca2+, the result indicates that the sensitivity of fura-2 for La3+ is much greater than for Ca2+. La3+ forms a 1:1 La3+-fura-2 complex (apparent dissociation constant = 1.7x10(-12) mol/L, pH 7.05). Ouabain-pretreated cells, suspended in Na+-free medium, showed that La3+ can enter human lymphocytes via the Na-i(+)/Ca2+ (La3+)(o) exchanger and is found to be about 10(-12) mol/L in cells exposed to 0.4 mmol/L La3+. Otherwise, the higher concentration (0.1 mmol/L) blocks the Na-i(+)/Ca2+(La3+)(o) exchange-mediated influx of Ca2+, but the lower concentration (0.01 mmol/L) appears to increase Ca2+ entry.

关键词： Na+/Ca2+ exchanger lymphocytes La3+ ouabain fluorescence indicator

The Intelligent Properties of Micro-reactors for Preparating Nanoparticles

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Chinese Chemical Letters 2003年第8期14卷 877-880页

作者： Gang WEI hai Yan HUANG Rong chun xiONG College of Materials Science and Engineering Beijing University of Chemical TechnologyBeijing 100029

TiO2 nanoparticles were synthesized by using micro-reactors. The shape and size of the nanoparticles produced from the original micro-reactors and the five times recycled micro-reactors mother liquor were investigated on transmission electron microscopy (TEM) by using the original sample, freeze prepared sample, and dyeing treated sample, respectively. UV-VIS spectrometry was used to study the growth process of TiO2 nanoparticles in main reactors. The results showed that micro-reactors with nanometer magnitude had spherical or oval structures, and could restore to their original structure after they were destroyed. The products prepared in the original micro-reactors were similar to that in the micro-reactors recycled for many times, suggesting that the micro-reactors had memory function.

关键词： Micro-reactors nanoparticles titanium dioxide intelligent properties.

Quantum dynamics of Gaudin magnets

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Communications in Theoretical Physics 2022年第9期74卷 39-48页

作者： Wen-Bin He Stefano Chesi hai-Qing Lin xi-Wen Guan Beijing Computational Science Research Center Beijing 100193China State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics Wuhan Institute of Physics and MathematicsAPMChinese Academy of SciencesWuhan 430071China The Abdus Salam International Center for Theoretical Physics Strada Costiera 11I-34151 TriesteItaly Department of Physics Beijing Normal UniversityBeijing 100875China NSFC-SPTP Peng Huanwu Center for Fundamental Theory Xi’an 710127China Department of Theoretical Physics Research School of Physics and EngineeringAustralian National UniversityCanberra ACT 0200Australia

Quantum dynamics of many-body systems is a fascinating and significant subject for both theory and *** question of how an isolated many-body system evolves to its steady state after a sudden perturbation or quench still remains *** this paper,using the Bethe ansatz wave function,we study the quantum dynamics of an inhomogeneous Gaudin *** derive explicit analytical expressions for various local dynamic quantities with an arbitrary number of flipped bath spins,such as:the spin distribution function,the spin-spin correlation function,and the Loschmidt *** also numerically study the relaxation behavior of these dynamic properties,gaining considerable insight into coherence and entanglement between the central spin and the *** particular,we find that the spin-spin correlations relax to their steady value via a nearly logarithmic scaling,whereas the Loschmidt echo shows an exponential relaxation to its steady *** results advance the understanding of relaxation dynamics and quantum correlations of long-range interacting models of the Gaudin type.

关键词： Gaudin magnets central spin model Bethe ansatz spin polarization spin-spin correlation Loschmidt echo