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一维有机导体的Peierls相变研究

物理学报 2004年第4期53卷 1162-1165页

作者：张红群北京师范大学物理系北京100875

根据建立在电子声子相互作用基础上的Peierls相变理论 ,利用形变势模型和半经验晶体轨道方法计算的能带结构数据 ,对一维有机导体tetrathiafulvalene tetracyanoquinodimethane的Peierls相变温度进行了计算 .并对其金属

关键词：有机导体 Peierls相变温度电子-声子相互作用能带结构哈密顿量泰勒展开

Quantum fluctuation dynamics in momentum spread of cold atoms

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原子与分子物理学报 2003年第4期20卷 549-552页

作者： WANG Zhong-jie, WANG Qin-mou, HUANG Wan-xia(department of Physics Anhui normal {2., Wuhu 2.1000, P. R. china) department of Physics Anhui normal {2. Wuhan 241000

Dynamics of the quantum system that consists of a cold atom in a modulated standing wave of light is analyzed using the time-dependent variational principle formulation based on squeezed coherent states. A group of ordinary differential equations describing evolution of two pairs of canonically conjugate variables (q(t), p(t); G(t), Π(t)) are derived where G(t) and Π(t) describe the quantum fluctuations of the system. It has been shown that a transition from the regular motion to the chaotic motion in G(t), Π(t) phase space. Quantum system seems to be capable to show the classical-like chaotic structure.

关键词：量子波动混沌量子力学薛定锷方程类经典混沌结构

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构造非线性发展方程孤波解的混合指数方法

物理学报 2002年第5期51卷 946-950页

作者：徐桂琼李志斌华东师范大学计算机科学技术系

介绍了Hereman等提出的构造非线性发展方程孤波解的混合指数方法 .依据数学机械化思想对该方法进行了改进和完善 ,使之能够求得非线性发展方程更多的孤波解。

关键词：非线性发展方程混合指数法孤波孤波解

Feedback minimization of first-passage failure of quasi integrable Hamiltonian systems

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Acta Mechanica Sinica 2007年第4期23卷 437-444页

作者： Maolin Deng Weiqiu Zhu department of Mechanics,State Key Laboratory of Fluid Power Transmission and Control,Zhejiang university,Hangzhou 31002.,{2. department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

Abstract A nonlinear stochastic optimal control strategy for minimizing the first-passage failure of quasi integrable Hamiltonian systems （multi-degree-of-freedom integrable Hamiltonian systems subject to light dampings and weakly random excitations） is proposed. The equations of motion for a controlled quasi integrable Hamiltonian system are reduced to a set of averaged It6 stochastic differential equations by using the stochastic averaging method. Then, the dynamical programming equations and their associated boundary and final time conditions for the control problems of maximization of reliability and mean first-passage time are formulated. The optimal control law is derived from the dynamical programming equations and the control constraints. The final dynamical programming equations for these control problems are determined and their relationships to the backward Kolmogorov equation governing the conditional reliability function and the Pontryagin equation governing the mean first-passage time are separately established. The conditional reliability function and the mean first-passage time of the controlled system are obtained by solving the final dynamical programming equations or their equivalent Kolmogorov and Pontryagin equations. An example is presented to illustrate the application and effectiveness of the proposed control strategy.

关键词： Nonlinear stochastic system First-passage time Reliability Stochastic control Dynamical programming

The Reflection of Cultural Differences in a Joint Performance

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梧州学院学报 2003年第1期 43-48页

作者： Wang Weiping1,Wang Ping2.(1.English department of Central china Technology {2. 430000 2. School of Foreign Language Literature of Wuhan {2. Wuhan china 430000)

Abstarct:This article tries to compare the difiererices between the Amarican and Chinese culture mainly through the comparison of a joint performance presented by the showcase of Birgham Young university,Haiwai and the music department of the Central{2. normal university regarding the difierences of its tempo,form,and Characters of the performers and further analyzes the cause of the differences and comes to the conclusion that although there are some melting phenomena in the process of cultural exchantge,the differences Would always exist.

关键词： culture cultual differences melting phenomena CLC number:G04 Document code:A

Hexafluoro-2.propanol as a potent cosolvent for chemical ligation of membrane proteins

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Science china Chemistry 2011年第1期54卷 110-116页

作者： SHEN Fei,TANG Shan & LIU Lei department of Chemistry,university of Science and Technology of{2.,Hefei 2.002.,china Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology,Ministry of Education department of Chemistry,Tsinghua university.Beijing 100084,china 1. department of Chemistry University of Science and Technology of China Hefei 230026 China2. Key Laboratory of Bioorganic Phosphorus Chemistry and Chemical Biology Ministry of Education department of Chemistry Tsinghua University Beijing 100084 China

The study on membrane proteins is an important challenge mainly because of their very poor solubility in various *** traditional recombinant expression strategy and the native chemical ligation method both have difficulty in generating sufficient amounts of desired proteins with high *** studies have shown that multiply fluorinated alcohols exhibit good ability to dissolve difficult peptide sequences,especially hexafluoro-2.propanol (HFIP).In the present study we systematically studied the capability of solvents containing different percentage of HFIP in dissolving transmembrane *** both HPLC and UV analyses we concluded that 60% HFIP/8 M urea constituted a good solvent *** this solvent system we also optimized conditions to perform native chemical ligation (NCL).Under the optimized conditions we successfully achieved NCL’s for both dipeptide formation and the synthesis of a model protein (Trifolitoxin).These results suggested that HFIP was a potential cosolvent that could be used in the ligation of poorly soluble peptides for the generation of membrane proteins.

关键词： membrane protein native chemical ligation alternative solvent hexafluoro-2.propanol

SURFACE MODIFICATION OF CaCO_3 WITH DENDRITIC CARBOXYLIC ACIDS

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Chinese Journal of Polymer Science 2002年第3期20卷 231-235页

作者： Zhao-xia Guo Jian Yu Institute of Polymer Science and Engineering department of Chemical Engineering Tsinghua university Beijing 100084{2. Tsing Hua Univ Dept Chem Engn Inst Polymer Sci & Engn Beijing 100084 Peoples R China

Nanometer calcium carbonate was modified with Frechet type polyether dendrons bearing a COOH group at thefocal point by a wet-coating technique in dichloromethane at room temperature. The interaction between CaCO;and thedendritic modifier was proven by IR and mass spectroscopy of the modified CaCO;after thorough extraction withdichloromethane. The amount of tightly bonded organic modifier was estimated by TGA. It was shown that the amount ofbonded molecules decreased with increasing generation number due to the larger number of branches. Compared tounmodified CaCO;, the modified CaCO;possess different dispersibility in water and in organic solvents.

关键词： calcium carbonate surface modification polyether dendrimer dendritic carboxylic acid

NUMERICAL SIMULATION OF MORPHOLOGY OF POLYMER CHAIN COILS IN COMPLEX FLOWS

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Chinese Journal of Polymer Science 2005年第5期23卷 453-462页

作者： Hong Zheng Wei Yu Chi-xing Zhou department of Polymer Materials Science & Engineering,Shanghai Jiaotong university,Shanghai 2.02.0,{2. Shanghai Jiao Tong Univ Dept Polymer Mat Sci & Engn Shanghai 200240 Peoples R China

A new coupled finite element formulation is proposed to calculate a conformation tensor model in two complex flows： a planar contraction flow and a planar flow around a symmetrically placed cylinder. The components of conformation tensor are first computed together with the velocity and pressure to describe the change of morphology of polymer chain coils in flow fields. Macroscopic quantities of viscoelastic flow are then calculated based on the conformation tensor. Comparisons between the numerical simulations and experiments for stress patterns and velocity profiles are carried out to prove the validity of the method.

关键词： Viscoelastic flow Morphology Complex flows Conformation tensor model Finite element method (FEM).

Tree wavelet approximations with applications

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Science china Mathematics 2005年第5期48卷 680-702页

作者： XU Yuesheng & ZOU Qingsong department of Mathematics, Syracuse university, Syracuse, NY 132.4, USA Institute of Mathematics, Academy of Mathematics and System Sciences, Chinese Academy of Sciences, Beijing 100080,{2. department of Scientific Computing and Computer Science, Zhongshan university, Guangzhou 5102.5,{2. 1. department of Mathematics Syracuse University 13244 Syracuse NY USA 2. Institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences 100080 Beijing China 3. department of Scientific Computing and Computer Science Zhongshan University 510275 Guangzhou China

We construct a tree wavelet approximation by using a constructive greedy scheme (CGS). We define a function class which contains the functions whose piecewise polynomial approximations generated by the CGS have a prescribed global convergence rate and establish embedding properties of this class. We provide sufficient conditions on a tree index set and on bi-orthogonal wavelet bases which ensure optimal order of convergence for the wavelet approximations encoded on the tree index set using the bi-orthogonal wavelet bases. We then show that if we use the tree index set associated with the partition generated by the CGS to encode a wavelet approximation, it gives optimal order of convergence.

关键词： greedy algorithms tree wavelet approximations Besov spaces.