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On mean curvatures in submanifolds geometry

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Science china Mathematics 2008年第6期51卷 1127-1134页

作者： GE JianQuan department of Mathematical Sciences,tsinghua University,beijing 100084,{3. department of Mathematical Sciences Tsinghua University Beijing 100084 China

By using moving frame theory,first we introduce 2p-th mean curvatures and(2p+1)-th mean curvature vector fields for a *** then give an integral expression of them that characterizes them as mean values of symmetric functions of principle *** we apply it to derive directly the celebrated Weyl-Gray tube formula in terms of integrals of the 2p-th mean curvatures and some Minkowski-type integral formulas.

关键词： moving frame mean curvature tube 53.07 53.42

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, beijing 100084, {3. 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

Optimal reactions for the synthesis of superheavy nucleus ^(270)Hs

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Science china(physics,Mechanics & Astronomy) 2006年第6期49卷 641-648页

作者： LIU Zuhua1,3.& BAO Jingdong1,2 1. Key Laboratory of Beam Technology and Material Modification of Ministry of Education, beijing Normal University, beijing 100875, china 2. {3. department, beijing Normal University, beijing 100875, china 3. china Institute of Atomic Energy, beijing 102413. china Key Laboratory of Beam Technology Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China physics department Beijing Normal University Beijing 100875 China china Institute of Atomic Energy Beijing 102413 China

The superheavy nucleus 270Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions 248Cm(26Mg,4n)270Hs, 244Pu(3.Si,4n)270Hs, 23.U(3.S,4n)270Hs and 226Ra(48Ca,4n)270Hs using a two-parameter Smoluchowski equation. It is found from our results that 226Ra(48Ca,4n)270Hs and 23.U(3.S,4n)270Hs are two optimal reactions for the synthesis of the superheavy nucleus 270Hs due to their large negative Q-values.

关键词： diffused fusion barrier,Smoluchowski equation,superheavy nuclei.

A quantification model for apoptosis in mouse embryos in the early stage of fetation

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Science china(Life Sciences) 2009年第10期52卷 922-927页

作者： WANG PengFei1, FU JianHua1, MA WanYun1, CHEN DieYan1, Lü DanYu2 & BAI WenJia3.1 Key Laboratory for Atomic and Molecular Nanosciences of Education Ministry, department of physics, tsinghua University, {3., china 2 department of Anatomy & Histology and Embryology, School of Basic Medical Sciences Peking University Health Science Center, beijing 100083. china 3.department of Automation, tsinghua University, {3., china 1. Key Laboratory for Atomic and Molecular Nanosciences of Education Ministry Department of Physics Tsinghua University Beijing 100084 China 2. department of Anatomy & Histology and Embryology School of Basic Medical Sciences Peking University Health Science Center Beijing 100083 China 3. department of Automation Tsinghua University Beijing 100084 China

Apoptosis is the most important inducement and modulator for embryos in the early stage of fetation, i.e. after the 8-cell stage, mostly the morula and blastula stage, to proceed to the stage of nonlinear development. Using a two-photon laser scanning microscopy (TPLSM) system, we obtained 3.dimensional (3.) fluorescent images of preimplantation mouse embryos. A model for quantification was established. The statistical results for the spatial location of apoptosis bodies in embryos was obtained following image processing, as well as investigation of the kinetics of apoptosis. It was found that most (70%) apoptosis occurred in the trophectoderm, and the departure between the centroid and geometric center of embryos had a step transition when embryos developed into the 3.-cell stage, which was consistent with the theoretical prediction that the blastocele would induce a symmetry break of the distribution of cells in embryos.

关键词： apoptosis preimplantation mouse embryo TPLSM quantification model

Plant protein kinase genes induced by drought, high salt and cold stresses

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Chinese Science Bulletin 2000年第13期45卷 1153-1157页

作者： LIU Qiang , ZHANG Yong & Chen Shouyi1. Deparlmenl of Biological Science and Biotechnology, tsinghua University, beijing 100084, china 2. {3. of Biological Science and Biotechnology, Slate Key Laboratory of Biomembrane and Membrane Biotechnology, tsinghua University, beijing 100084, china 3. Institute of Genetics, Chinese Academy of Sciences, beijing 100101, china department of Biological Science and Biotechnology Tsinghua University Beijing China department of Biological Science and Biotechnology State Key Laboratory of Biomembrane and Membrane Biotechnology Tsinghua University Beijing China Institute of Genetics Chinese Academy of Sciences Beijing China

Drought, high salt and cold are three different kinds of environment stresses that severely influence the growth, development and productivity of crops. They all decrease the water state of plant cells, and consequently result in the harm of plant from water deficit. Several genes encoding protein kinases and induced by drought, high salt and low temperature have been isolated from Arabidopsis. These protein kinases include receptor protein kinase (RPK), MAP kinases, ribosomal-protein kinases and transcription-regulation protein kinase. The expression features of these genes and the regulatory roles of these protein kinases in stress response and signal transduction are discussed.

关键词： protein kinase environment stress signal transduction gene expression.

Truncation error calculation based on Richardson extrapolation for variable-step collaborative simulation

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Science china(Information Sciences) 2011年第6期54卷 1238-1250页

作者： ZHANG HeMing 1 , LIANG SiLu 2 , SONG ShiJi 1 & WANG HongWei 3.1 department of Automation, TNList, tsinghua University, beijing 100084, {3. 2 Computer and Information Management Center, tsinghua University beijing 100084, {3. 3.Engineering Design Centre, Engineering department, Cambridge University, Cambridge CB2 1PZ, UK 1. department of Automation TNList Tsinghua University Beijing 100084 China2. Computer and Information Management Center Tsinghua University Beijing 100084 China3. Engineering Design Centre Engineering Department Cambridge University Cambridge CB2 1PZ UK

Collaborative simulation is an effective approach to performing simulation analysis for complex systems by integrating models developed for different engineering disciplines. Collaborative simulation issues include the modeling of coupled multidisciplinary systems, and the simulation running time integration of these models that are solved parallelly. Estimation of the local truncation error of coupling models is the key to solve multidisciplinary collaborative simulation problem, which is actually used to restrict the simulation step. This paper presents a variable-step method based on Richardson extrapolation for calculating the local truncation error to solve collaborative simulation problem of multidisciplinary coupling models. Formulas for estimating the local truncation error are derived through theoretical analysis by using integration methods and interpolation technologies, respectively. The simulation experiments are illustrated to validate the accuracy and efficiency of proposed collaborative simulation algorithm in comparison with the usual combinative algorithm.

关键词： multidisciplinary systems collaborative simulation variable-step algorithm error estimation

Parameter identification theory of a complex model based on global optimization method

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Science china(physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1, JIN QuanLin2 & XU BingYe3.1 College of Automotive Engineering, South china University of Technology, Guangzhou 510640, china 2 beijing Research Institute of Mechanical and Electrical Technology, beijing 100083. china 3.department of Engineering Mechanics, tsinghua University, beijing 100084, china 1. College of Automotive Engineering South China University of Technology Guangzhou 510640 China 2. beijing Research Institute of Mechanical and Electrical Technology Beijing 100083 China 3. department of Engineering Mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the design of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the designed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

Timeliness evaluation of task-oriented networked space-based information system

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Journal of Systems Engineering and Electronics 2011年第4期22卷 621-627页

作者： Chen Chen 1,2,and Jie Chen 2,3.1.department of Automation,tsinghua University,beijing 100084,P.R.{3. 2.School of Automation,beijing Institute of Technology,beijing 100081,P.R.{3. 3.Complex System Intelligent Control and Decision,Ministry of Education,beijing 100081,P.R.{3. department of Automation Tsinghua University Beijing 100084 P. R. China School of Automation Beijing Institute of Technology Beijing 100081 P. R. China School of Automation Beijing Institute of Technology Beijing 100081 P. R. China Complex System Intelligent Control and Decision Ministry of Education Beijing 100081 P. R. China

Task-oriented networked information system is an integrated information system which builds on multi-satellite networking to accomplish one or more tasks. In the background of emer- gency relief for applications, system working flow and response process are analyzed, and a timeliness effectiveness evaluation index system is constructed at multi-task level. The effectiveness is a measurement of promptness of information return. In evalua- tion process, system performance and tasks are associated, then an evaluation model based on efficacy function is established, and different evaluation criteria are selected for different tasks. A distributed simulation system is constructed, and the execution of task is decomposed. The simulation platform provides a comprehensive data source for evaluation. The results are easy to compare with each other, which reflects system time efficiency in different satellites networks and provides actual systems with basis and reference for design and application.

关键词： timeliness efficacy function space-based informationsystem simulation system.

Cilia and ciliopathies:From Chlamydomonas and beyond

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Science china(Life Sciences) 2008年第6期51卷 479-486页

作者： PAN JunMin department of Biological Sciences and Biotechnology, tsinghua University, beijing 100084, {3. 1. department of Biological Sciences and Biotechnology Tsinghua University Beijing 100084 China

The biological function of motile cilia/flagella has long been recognized. The non-motile primary cilium, once regarded as a vestigial organelle, however, has been found recently to play unexpected roles in mammalian physiology and development. Defects in cilia have profound impact on human health. Diseases related to cilia, collectively called ciliopathies include male infertility, primary cilia dyskinesia, renal cyst formation, blindness, polydactyly, obesity, hypertension, and even mental retardation. Our current understanding of cilia and ciliopathies has been fueled by basic research employing various model organisms including Chlamydomonas, a unicellular green alga. This review article provides a general introduction to the cell biology of cilia and an overview of various cilia-related diseases.

关键词： Chlamydomonas cilia flagellla human disease ciliopathy