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Nonlinear Refractive Index and Absorption Coefficient of Single-Shell Semiconductor Carbon Nanotube

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wuhan University Journal of Natural Sciences 2003年第3A期8卷 833-836页

作者： Lu Ni,Xiong Gui\|guang  school of physics and {2., wuhan University, wuhan 4.0072, hubei, china wuhan University School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The nonlinear refractive index and absorption coefficient of single\|shell semiconductor carbon nanotubes(CN s ) are calculated based on the two\|band approximation and Genkin\|Mednis approach. The results of nonlinear refractive index and absorption coefficient reach the order of 10 -8 and 10 -4. cm 2.5W -1 separately, which indicates that CN s have wonderful nonlinear optical properties. Taking into account the temperature effect and overlapping of σ and π orbits, the effect of relaxation term and chiral angle is discussed. The results show that the smaller the relaxation term, the larger the nonlinear absorption coefficient and refractive index. At the same time, CN s with different chiral angles have different results due to their different energy gap.

关键词： nonlinear refractive index nonlinear absorption coefficient relaxation chiral angle

A Multi-Soliton Solution of the DNLS Equation Based on Pure Marchenko Formalism

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wuhan University Journal of Natural Sciences 2010年第1期15卷 36-42页

作者： ZHOU Guoquan school of physics and {2.,wuhan University,wuhan 4.0072.hubei,china school of physics and {2. Wuhan University Wuhan China

By means of some algebraic techniques,especially the Binet-Cauchy formula,an explicit multi-soliton solution of the derivative nonlinear Schrdinger equation with vanishing boundary condition is attained based on a pure Marchenko formalism without needing the usual scattering data except for given N simple poles. The one-and two-soliton solutions are given as two special examples in illustration of the general formula of multi-soliton solution. Their effectiveness and equivalence to other approaches are also demonstrated. Meanwhile,the asymptotic behavior of the multi-soliton solution is discussed in detail. It is shown that the N-soliton solution can be viewed as a summation of N one-soliton solutions with a definite displacement and phase shift of each soliton in the whole process(from t →∞ to t → +∞ ) of the elastic collisions.

关键词： soliton derivative nonlinear Schrdinger (DNLS) equation nonlinear equation Marchenko equation

Effect of Substrate-Water Interaction on the Wetting Behavior in Water-Oil and Substrate-Water-Oil Systems

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wuhan University Journal of Natural Sciences 2003年第4A期8卷 1097-1102页

作者： Yuan Yin-quan 1,2., Zou Xian-wu 1 , Jin Zhun-zhi 1 1. school of physics and {2., {4. University, {4. 4.0072, hubei, china 2. Department of physics, Xiaogan University, Xiaogan 4.2.00, hubei, china wuhan University School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***) Xiaogan University Department of Physics Xiaogan Hubei China (GRID:grid.49470.3e) wuhan University School of Physics and Technology Wuhan Hubei China (GRID:grid.49470.3e) (ISNI:***)

The effects of the substrate-water interaction on the wetting behavior in water-oil and surfactant-water-oil systems confined by one substrate which has the preferential interaction to one species of particles have been investigated by using the free energy analysis and discontinuous molecular dynamic simulations. As the preferential interaction between the substrate and water particles varies from small repulsion to large attraction, the partial drying, partial wetting and complete wetting state are observed in sequence. In addition, the wetting behavior of surfactant aqueous solution on the substrate is not only dependent on the interaction, but also limited by the maximum equilibrium concentration of surfactants at the interface.

关键词： wetting behavior wetting transition preferential interaction substrate

Electron microscopy study of the sakhaite from endogenous borate deposit in Hunan, china

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Science china Earth Sciences 2004年第3期47卷 232-238页

作者： LIU Xiangwen1,2. YANG Guangming2. ZOU Huamin3, QU Jing1 & ZHAO Wenxia4.1. Graduate school, china University of Geosciences, {2. 4.0074. china 2. Test Center, china University of Geosciences, {2. 4.0074. china 3. physics and technology College, {2. University, {2. {14., china 4. Test Center, Zhongshan University, Guangzhou 5102.5, china china Univ Geosci Grad Sch Wuhan 430074 Peoples R China china Univ Geosci Test Ctr Wuhan 430074 Peoples R China wuhan Univ Phys & Technol Coll Wuhan 430072 Peoples R China Zhongshan Univ Test Ctr Guangzhou 510275 Peoples R China

Sakhaite specimens from an endogenous borate deposit in Hunan Province, china have been studied in detail by means of transmission electron microscopy (TEM). The selected area electron diffraction (SAED) patterns obtained with different crystal zone axes show that the crystal system is cubic, with a = 1.4.3 nm. The convergent beam electron diffraction (CBED) patterns indicate that the point group and space group of sakhaite is m3m and Fd3m, respec-tively. The space group of synthetic sakhaite determined by Chichagov (1974. is F4.32. The possible reasons why the space groups of the natural and the synthetic sakhaites are different are discussed.

关键词： sakhaite, space group, convergent beam electron diffraction (CBED).

Numerical simulations and experimental investigations on transverse effects of two-wave mixing in a photovoltaic photorefractive crystal

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Science china(physics,Mechanics & Astronomy) 2010年第5期53卷 856-863页

作者： CAI Xin1,2.LIU JinSong1 & WANG ShengLie1 1 wuhan National Laboratory for Optoelectronics,school of Optoelectronic Science and Engineering,Huazhong University of Science and {2.,wuhan 4.0074.china 2.school of Science,wuhan University of {2.,wuhan 4.0070,china 1. wuhan National Laboratory for Optoelectronics School of Optoelectronic Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China2. School of Science Wuhan University of Technology Wuhan 430070 China

The transverse effects of two Gauss waves mixing in a photovoltaic photorefractive crystal,i.e.,the dynamical evolutions of signal beam with different parameters,are traced numerically and *** the one-dimensional numerical simulations and two-dimensional experimental investigations show that the self-focusing effect of signal beam becomes more obvious as the intensity of pump beam and the angle between the signal and pump beams *** accordance with these results,the state of two Gaussian waves mixing is controllable.

关键词： numerical simulation experimental investigation two-wave mixing transverse effects Gaussian distribution

Ferroelectric properties of Bi_(3.4.Ho_(0.6)Ti_3O_(12. thin films prepared by sol-gel method

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Science china(Technological Sciences) 2008年第9期51卷 1439-1444页

作者： FU ChengJu1, HUANG ZhiXiong1, LI Jie2.& GUO DongYun3 1 school of Materials Science and technology, {2. University of technology, {2. 4.0070, china 2.school of Mechanical Engineering, Chongqing University of Science and technology, Chongqing 4.0050, china 3 Department of physics, {2. University, {2. {12., china school of Materials Science and technology Wuhan University of Technology Wuhan 430070 China school of Mechanical Engineering Chongqing University of Science and Technology Chongqing 400050 China Department of physics Wuhan University Wuhan 430072 China

We have prepared the Ho-substituted bismuth titanate (Bi3.4.o0.6Ti3O12. BHT) thin films on Pt/Ti/SiO2.Si substrates using sol-gel method. The crystal structure and morphology of the films were characterized using X-ray diffraction and atomic force microscopy. The BHT film shows a single phase of Bi-layered Aurivillius structure and dense microstructure. The 2.r and 2.c of the 600-nm-thick BHT film were 38.4.μC/cm2.and 376.1 kV/cm, respectively at applied electric field 500 kV/cm. The dielectric constant and dielectric loss are about 310 and 0.015 at a frequency of 1 MHz, respectively. The Pr value decreased to 93% of its pre-fatigue values after 4.4.×109 switching cycles at 1 MHz frenquency, and the BHT film shows good in-sulating behavior according to the test of leakage current.

关键词： Bi3.4.o0.6Ti3O12 thin film sol-gel method ferroelectric property fatigue dielectric constant

Evidence of Positron Trapping into Defects in Zn-Doped GaAs

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wuhan University Journal of Natural Sciences 2003年第4A期8卷 1103-1106页

作者： Wang Zhu, Zheng Zi-yao, Su Ben-fa, Hu Wei-guo school of physics and {2., wuhan University , wuhan 4.0072, hubei, china wuhan University

The defect properties in as-grown and deformed p-type GaAs with different concentration of dopants and different growth method have investigated by positron lifetime measurement. The result indicates that no positron trapping was observed in LEC-grown Zn-doped p-type GaAs. However, in HB- and FZ-grown Zn-doped GaAs, positron trapping into vacancy type defects was observed. In deformed samples, clusters were formed during deformation. Positron detected shallow positron traps and the dominant shallow positron traps were attributed to Zn acceptors in Zn-doped GaAs.

关键词： positron annihilation defect semiconductor deformation p-type GaAs

Exploring non-equilibrium statistical ensembles

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Science Bulletin 2011年第34期56卷 3654-3660页

作者： BI Qiao & LIU Jie Department of physics, school of Science, {2. University of technology, {2. 4.0070, china Department of physics School of Science Wuhan University of Technology

Since Gibbs synthesized a general equilibrium statistical ensemble theory, generalizing the Gibbsian theory to non-equilibrium phenomena has been a dream for some theorists. However, the status of the theory for the non-equilibrium ensemble formalism is not as well established as the Gibbsian ensemble theory. In this work, we explore the formalism behind the non-equilibrium statistical ensemble theory based on the sub-dynamic kinetic equation originating from the Brussels-Austin school and developed further by others. The key is establishing a similarity transformation between Gibbsian ensembles and the sub-dynamic ensemble. Using this way, we study a spin-Boson model with strong coupling. A reduced density operator for the canonical ensemble can be easily obtained and the relevant decoherence-free property is revealed.

关键词： subdynamics statistical ensemble non-equilibrium statistical physics

The feature study on the π and proton rapidity distributions at AGS, SPS and RHIC

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Science china(physics,Mechanics & Astronomy) 2009年第2期52卷 198-206页

作者： FENG ShengQin1,2.& YUAN XianBao1,3 1 College of Science, china Three Gorges University, Yichang 4.3002. china 2.{2. of physics and technology, wuhan University, wuhan 4.0072, china 3 Institute of Particle physics, Central china Normal University, wuhan 4.0070, china 1. College of Science China Three Gorges University Yichang 443002 China 2. school of physics and technology Wuhan University Wuhan 430072 China 3. Institute of Particle physics Central China Normal University Wuhan 430070 China

The features of nuclear stopping power and multi-hadron production systematically are studied by making an analysis of rapidity distributions of pion and proton at AGS, SPS and RHIC in this work. It is found that nuclear stopping power increases linearly with project rapidity yp at AGS and SPS, but that is not liner at RHIC. It is argued that the average rapidity loss is saturated at central rapidity region at RHIC. For pion distribution, it is found that the phase space of pion distribution distributes uniformly in the longitudinal direction,and a linear relationship of L with log s is given at AGS and SPS. Non-uniform flow model may explain the features of the distribution at AGS and SPS, but may not ex- plain those of at RHIC.

关键词： non-uniform flow model average rapidity loss baryon number density nuclear stopping power