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Fluorescence fluctuation spectroscopy and its artifacts:simulations and tests

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Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 336-344页

作者： MENG Fanbo 1 , CHEN Bo 1 , LIU Guang 1 , DING Jianying 1 & MA Hui 2.1 1. department of Physics and Key Laboratory of Atomic and Molecular Nano Sciences, Ministry of Educa- tion, tsinghua university,{2., china 2. Graduate School at Shenzhen, tsinghua university, Shenzhen 518055, china 1. department of Physics and Key Laboratory of Atomic and Molecular Nano Sciences Ministry of Education Tsinghua University 100084 Beijing China 2. Graduate School at Shenzhen Tsinghua University 518055 Shenzhen China

Fluorescence fluctuation spectroscopy (FFS) technique is capable of monitoring changes in concentration, mass, size and structure of fluorescent-labeled bio-molecules in microscopic volume and is suitable for measuring biological interactions in living cells. FFS data may be affected by many experimental factors in complicated biological systems. Using a Monte Carlo approach, we generate fluorescence fluctuation data for different experimental systems. This approach helps to separate the contributions by different experimental factors in a complicated fluorescence fluctuation spectrum. It also helps to validate new theoretical models and new fitting formulations. We describe the algorithm of the simulation program and tests on its statistical performance. The program is then used successfully to study the effects of several experimental factors on FFS detection.

关键词： fluorescence fluctuation spectroscopy, fluorescence correlation spectroscopy, Monte Carlo simulation.

AR quivers,exceptional sequences and algorithms in derived Hall algebras

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Science china Mathematics 2010年第6期53卷 1609-1624页

作者： SHENG Jie department of Mathematical Sciences,tsinghua {2.,beijing 1.0084,china 1. department of Mathematical Sciences Tsinghua University Beijing 100084 China

Consider the canonical isomorphism between the positive part U+ of the quantum group Uq(g) and the Hall algebra H(Λ),where the semisimple Lie algebra g and the finite-dimensional hereditary algebra Λ share a Dynkin *** and Xiao have given two algorithms to decompose the root vectors into linear combinations of monomials of Chevalley generators of U+,respectively induced by the braid group action on the exceptional sequences of Λ-modules and the structure of the Auslander-Reiten quiver of Λ.In this paper,we obtain the corresponding algorithms for the derived Hall algebra DH(Λ),which was introduced by *** show that both algorithms are applicable to the lattice algebra and Heisenberg double in the sense of *** the new recursive formulae have the same flavor with the quantum Serre relations.

关键词： derived Hall algebra exceptional sequence AR quiver

On fixed-points and singular values of transcendental meromorphic functions

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Science china Mathematics 2010年第3期53卷 887-894页

作者： ZHENG JianHua department of Mathematical Sciences, tsinghua university,{2., china 1. department of Mathematical Sciences Tsinghua University Beijing 100084 China

In this paper we make a further discussion of a relationship between the number of fixed-points and distribution of singular values along the round annuli centered at the origin of a transcendental meromorphic function. To attain our purpose we first establish a fundamental inequality for the modulus of derivative of a holomorphic covering mapping whose image is an annulus by virtue of the hyperbolic metric. The inequality is of independent significance. We make a simple survey on some domain constants for hyperbolic domains.

关键词： meromorphic functions fixed points singular points hyperbolic metric covering mapping

Design of policy mechanism to promote cleaner production in china

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Journal of Environmental Sciences 2001年第3期13卷 346-350页

作者： ZHANG Tian zhu(department of Environmental Science and Engineering, tsinghua university,{2., china. department of Environmental Science and Engineering Tsinghua University Beijing 100084 China. zhangtz@***

In order to promote cleaner production in china, a package of policy options was presented based on the identification of the barriers encountered in the CP demonstration project and the effectiveness and feasibility of policy options for the CP implementation were analyzed. Furthermore, the policy mechanism framework was given, which composes of compulsory, economic incentive, social pressure and supportive function. Finally, the implementation strategy of the policy mechanism, in which the emphasis will be changed from compulsory policy options towards economic and social pressure policy options, was proposed.

关键词： cleaner production barrier identification policy mechanism china

A BOUNDARY ELEMENT APPROXIMATION OF A SIGNORINI PROBLEM WITH FRICTION OBEYING COULOMB LAW

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Journal of Computational Mathematics 1994年第2期12卷 147-162页

作者： Han Hou-de(department of Applied Mathematics, tsinghua university, {2., china) TSING HUA UNIV DEPT APPL MATHBEIJINGPEOPLES R CHINA

In this work, a Signorini problem with Coulomb friction in two dimensional elasticity is considered. Based on a new representation of the derivative of the double-layer potential, the original problem is reduced to a system of variational inequalities on the boundary of the given domain. The existence and uniqueess of this system are established for a small frictional coefficient. The boundary element approximation of this system is presented and an error estimate is given.

关键词： A BOUNDARY ELEMENT APPROXIMATION OF A SIGNORINI PROBLEM WITH FRICTION OBEYING COULOMB LAW Ph

Existence of the solutions and the attractors for the large-scale atmospheric equations

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Science china Earth Sciences 2006年第6期49卷 650-660页

作者： HUANG Haiyang1 & GUO Boling2.1. department of Mathematics, beijing Normal {2., beijing 100875, china 2. Institute of Applied Physics and Computational Mathematics, beijing 100080, china 1. department of Mathematics Beijing Normal University Beijing 100875 China 2. Institute of Applied Physics and Computational Mathematics Beijing 100080 China

In this paper, firstly, the proper function space is chosen, and the proper expression of the operators is introduced such that the complex large-scale atmospheric motion equations can be described by a simple and abstract equation, by which the definition of the weak solution of the atmospheric equations is made. Secondly, the existence of the weak solution for the atmospheric equations and the steady state equations is proved by using the Galerkin method. The existence of the non-empty global attractors for the atmospheric equations in the sense of the Chepyzhov-Vishik’s definition is obtained by constructing a trajectory attractor set of the atmospheric motion equations. The result obtained here is the foundation for studying the topological structure and the dynamical behavior of the atmosphere attractors. Moreover, the methods used here are also valid for studying the other atmospheric motion models.

关键词： atmosphere equations, weak solution, trajectory attractor, global attractor, equilibrium.

Application and Comparison of Two SGS Models in Large Eddy Simulation of FreeTurbulent Jet Flow

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Communications in Nonlinear Science and Numerical Simulation 1999年第1期4卷 12-19页

作者： Hong YAN and Mingde SU (department of Engineering Mechanics, tsinghua university,{2., china) department of Engineering Mechanics Tsinghua University Beijing 100084 China

Large eddy simulations of spatially evolved turbulent round jets were presented. The two SGS models called the standard Smagorinsky’s eddy viscosity model and the non-eddy viscosity stimulated small scale(SSS) model developed by Shah & Ferziger were applied. The Reynolds number of the flow was taken as 10000 based on the orifice diameter and the axial velocity in the orifice. The comparison between these two models showed that the standard Smagorinsky’s viscosity model with Smagorinsky’s constant of 0.1 underestimated the turbulent intensity, while the SSS model showed a better agreement with the experiment. Also the SSS model was used to investigate the development of vortex. The convective boundary condition at the outflow boundary was adopted to ensure less effect of noise on the upstream.

关键词： stimulated small scale model smagorinsky’s eddy viscosity model Round jet, Large eddy simulation

The numerical method for three-dimensional impact with friction of multi-rigid-body system

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Science china(Physics,Mechanics & Astronomy) 2006年第1期49卷 102-118页

作者： ZHAO Zhen1,2. LIU Caishan2.& CHEN Bin2.1. beijing Institute of Graphic Communication, beijing 102.00,{2. 2. department of Mechanics & Engineering Science, Peking university, beijing 100871,{2. beijing Institute of Graphic Communication Beijing 102600 China department of Mechanics & Engineering Science Peking University Beijing 100871 China

The differential equations for planar impacts reduce to an algebraic form, and can be easily solved. For three dimensional impacts with friction, there is no closed-form solution, and numerical integration is required due to the swerve behavior of tangential impulse during collisions. The dynamic governing equations in the impact process are built up in impulse space based on the Lagrangian equation in this paper. The coefficient of restitution defined by Poisson is used as the condition of impact termination. A valid nu- merical method for solving three-dimensional frictional impact of multi-rigid body system is established. The singular cases of tangential movement in sticking point are especially noticed and analyzed. Several examples are present to reveal the different kinds of tan- gential movement modes varied with the normal impulse during collision.

关键词： multi-rigid body, impact, friction.

APPLICATION OF MOLECULAR ORBITAL THEORY TO ANALYSIS OF PHASE STABILITY FOR ALLOYS

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Acta Metallurgica Sinica(English Letters) 1993年第3期6卷 145-152页

作者： YIN Hong TAO Kun PAN Jinsheng LI Hengde tsinghua university,beijing,{2. professor.department of Materials Science and Engineering,tsinghua university,beijing 1.0084,{2. tsinghua Univ Beijing China

The critical _d vahues ( _ ) of the γ/(γ+σ).γ/(γ+μ) and γ/(γ+γ') phase boundaries in some ternar alloy phase diagrams at various temperatures are calculated by averaging the _d values of sererai selected characteristic points at the phase *** equations for the temperature dependence of the critical _d of γ/(γ+σ).γ/(γ+μ) and γ/(γ+γ') phase boundaries are *** accuracy of the analysis is discussed in detail. It is found for the first time that the average value of the bond order _ at the phase boundaries ts also approximatelr a constant and therefore a critical average bond order _ like - can be introduced for the analysts of phase stability

关键词： molecular orbital theory allov phase stabilitv