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First-principles study on the electronic structure and optical properties of CrSi_2

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Science china(physics,Mechanics & Astronomy) 2009年第1期52卷 46-51页

Using the first principle methods based on the plane-wave pseudo-potential theory, band structure, density of states and optical properties of CrSi2 were studied. The calculation of band structure shows that CrSi2 is an indirect semiconductor whose band gap is 0.353 eV. Density of states is mainly composed of 3d electron of Cr and 3p electron of Si. Dielectric function, refractive index, reflectivity, and absorption coefficient of CrSi2 are also calculated. The calculation results of optical properties are in agreement with the experiments.

关键词： CrSi2 electronic structure optical properties first principles

Robustness and breakup of the spiral wave in a two-dimensional lattice network of neurons

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Science china(physics,Mechanics & Astronomy) 2010年第4期53卷 672-679页

作者： MA Jun 1,2, TANG Jun 2 , ZHANG AiHua 3 & JIA Ya 2 1 department of physics, Lanzhou University of Technology, Lanzhou 730050, china 2.department of physics, Central china Normal University, Wuhan 430079, china 3 college of Electrical and Information Engineering, Lanzhou University of Technology, Lanzhou 730050, china 1. department of physics Lanzhou University of Technology Lanzhou 730050 China2. Department of Physics Central China Normal University Wuhan 430079 China3. College of Electrical and Information Engineering Lanzhou University of Technology Lanzhou 730050 China

The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.

关键词： spiral wave factor of synchronization breakup multiplicative noise robustness

Non-universal Gauge Bosons Z'and the Process e~+e~- →f

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Communications in Theoretical physics 2004年第3期41卷 419-424页

作者： YUE Chong-Xing~1 WANG Shun-Zhi~2 1 department of physics,Liaoning Normal University,Dalian 116029,china 2 college of physics and Information Engineering,Henan Normal University,Xinxiang 453002,china department of physics Liaoning Normal University Dalian 116029 college of physics and Information Engineering Henan Normal University Xinxiang 453002

Introduetion Altl、ough the standard model(SM)that bases on thega、lge gro、ip SU:(2)xU(1)has been sueeessful in de-seribing the Physies of eleetroweak interaetions,the meeh-anisn,of the eleetroweak symmetry breaking(... 详细信息

关键词： non-universal gauge bosons cross section TC2 models

Anisotropic effect on the vibronic reduction factors

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Chinese Science Bulletin 2006年第21期51卷 2553-2558页

作者： QIU Qing-chun1,2 & QIAO Fen1,2 1. department of physics and IT, Medical college, Shantou University,Shantou 515041, china 2. department of physics, Shantou University, Shantou 515063, china department of physics and IT Medical College Shantou University Shantou 515041 China department of physics Shantou University Shantou 515063 China

The reduction factors p and q defined by Ham in the Ee JT system and their relation 2q-p=1 have been well accepted and the concept of reduction factors is widely used in the studies of vibronic coupling. However, when the system is under the anisotropic conditions, the reduction factors and their relation will change accordingly. The first-order reduction factors p and q of Ee system were further studied using the method of unitary transformation here. The relation between p and q proposed by Ham was investigated under both conditions of the linear coupling and the anisotropic effects. The result demonstrated that the relation of 2q-p=1 was only correct for the linear vibronic coupling, but not correct when the anisotropic effect was considered. This result suggested that the anisotropic effect influence considerably the reduction factors, and hence the physical properties of materials. Our method could be also applied to other JT systems, especially the highly symmetric JT systems involving C60 molecules.

关键词：电子振动耦合声子交迭 Jahn-Teller效应各向异性

Particle tunnels across the horizon of Garfinkle-Horowitz-Strominger dilaton black hole

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Science china(physics,Mechanics & Astronomy) 2007年第5期50卷 601-610页

作者： FANG HengZhong1 & ZHAO Zheng2 1 department of physics, china University of Petroleum, Dongying 257061, china 2.department of physics, Beijing Normal University, Beijing 100875, china department of physics China University of Petroleum Dongying 257061 China department of physics Beijing Normal University Beijing 100875 China

We promote the work of Parikh and Wilczek on the black hole radiation to the emission of massive and charged particles from Garfinkle-Horowitz-Strominger black hole. The energy and charge of the space-time are conservational during the course of the evaporation. The calculation shows that the emission spectrum is not precisely thermal, while has a correction, and the conclusion supports the view- point of information conservation.

关键词： Hawking radiation, black body spectrum, barrier, information loss, entropy of black hole, Komar energy

Microwave peak absorption frequency of liquid

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Science china(physics,Mechanics & Astronomy) 2008年第9期51卷 1254-1263页

作者： HAN GuangZe1 & CHEN MingDong2 1 department of physics,South china University of Technology,Guangzhou 510640,china 2 Guangzhou Auto college,South china University of Technology,Guangzhou 510800,china 1. department of physics South China University of Technology Guangzhou 510640 China 2. Guangzhou Auto college South China University of Technology Guangzhou 510800 China

Microwave-assisted extraction is a new effective method which has practical ap-plications in many fields. Microwave heating is one of its physical mechanisms,and it also has the characteristic of selectivity. When the applied microwave fre-quency equals a certain absorption frequency of the material (or specific compo-nent),the material will intensively absorb microwave energy. This is also known as resonant absorption,and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work,dynamic hy-drogen bond energy was included in molecular activation energy; with the liquid cell model,the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and re-laxation time,the expression of microwave peak absorption frequency as a func-tion of the material physical structure,rotational inertia and electrical dipole mo-ment of molecules was established. These theoretical formulas were applied to water and benzene,and the calculated results agree fairly well with the experi-mental data. This work can not only deepen the study of the interaction between microwave and material,but also provide a possible guide for the experiment of microwave-assisted extraction.

关键词： microwave-assisted extraction microwave heating relaxation time liquid viscosity peak absorption fre-quency

Variable Separation Solution for(1+1)-Dimensional Nonlinear Models Related to Schrdinger Equation

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Communications in Theoretical physics 2004年第10期42卷 568-572页

作者： XU Chang-Zhi~(1,2) ZHANG Jie-Fang~11 Institute of Nonlinear physics,Zhejiang Normal University,Jinhua 321004,china2.department of physics and Mathematics,Jinhua Educational college,Jinhua 321000,china department of physics and Mathematics Jinhua Educational College Jinhua 321000 China

A variable separation approach is proposed and successfully extended to the(1+1)-dimensional *** new exact solution of(1+1)-dimensional nonlinear models related to Schr(?)dinger equation by the entranceof three arbitrary functions is *** special types of soliton wave solutions such as multi-soliton wave solution,non-stable soliton solution,oscillating soliton solution,and periodic soliton solutions are discussed by selecting thearbitrary functions appropriately.

关键词： variable separation approach (1+1)-dimensional nonlinear models solution of soliton

A Classical Toda Family with a Common Virasoro Symmetry Algebra

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Communications in Theoretical physics 2004年第6期41卷 813-815页

作者： QIAN Xian-Min LOU Sen-Yue ~1department of physics,Shanghai Jiao Tong University,Shanghai 200030,china ~2department of physics,Shaoxing college of Arts and Sciences,Shaoxing 312000,china department of physics,Ningbo University,Ningbo 315211,china department of physics Ningbo University Ningbo 315211 China

By means of a simple ideal,which is firstly proposed for the continuous system,we present an arbitraryorder classical Toda family invariant under common Virasoro-type symmetry algebra.

关键词： classical Toda family Virasoro symmetry algebra

Quantum statistical entropy corresponding to cosmic horizon in five-dimensional spacetime

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Science china(physics,Mechanics & Astronomy) 2008年第2期51卷 140-146页

作者： ZHAO Ren1,2 & ZHANG ShengLi1 1 department of Applied physics, Xi’an Jiaotong University, Xi’an 710049, china 2.department of physics, Shanxi Datong University, Datong 037009, china department of Applied physics Xi’an Jiaotong University Xi’an 710049 China department of physics Shanxi Datong University Datong 037009 China

The generalized uncertainty relation is introduced to calculate the quantum statis-tical entropy corresponding to cosmic horizon. By using the new equation of state density motivated by the generalized uncertainty relation, we discuss entropies of Bose field and Fermi field on the background of five-dimensional spacetime. In our calculation, we need not introduce cutoff. There is no divergent logarithmic term in the original brick-wall method. And it is obtained that the quantum statistical en-tropy corresponding to cosmic horizon is proportional to the area of the horizon. Further it is shown that the entropy corresponding to cosmic horizon is the entropy of quantum state on the surface of horizon. The black hole's entropy is the intrinsic property of the black hole. The entropy is a quantum effect. In our calculation, by using the quantum statistical method, we obtain the partition function of Bose field and Fermi field on the background of five-dimensional spacetime. We provide a way to study the quantum statistical entropy corresponding to cosmic horizon in the higher-dimensional spacetime.

关键词： quantum statistical entropy generalized uncertainty relation high-dimensional spacetime