检索结果-南通市图书馆

Challenges in the theoretical investigations of lipid membrane configurations

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2013年第2期22卷 36-44页

作者：涂展春 department of Physics Beijing Normal University Kavli Institute for Theoretical Physics china Chinese Academy of Sciences

We report some key results in the theoretical investigations of configurations of lipid membranes and present several challenges in this field,which involve（i）the exact solutions to the shape equation of lipid vesicles,（ii）the exact solutions to the governing equations of open lipid membranes,（iii）the neck condition of two-phase vesicles in the budding state,（iv） the nonlocal theory of membrane elasticity,and（v）the relationship between the symmetry and the magnitude of the free energy.

关键词： configuration lipid membrane

Gas kinetic algorithm for flows in Poiseuille-like microchannels using Boltzmann model equation

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & astronomy) 2005年第4期48卷 496-512页

作者： LI Zhihui1,2, ZHANG Hanxin1 & FU Song2 ⒈ National Laboratory for CFD, Hypervelocity Aerodynamics Institute,china Aerodynamics Research and Development Center,Mianyang 621000,china 2.department of Engineering Mechanics,Tsinghua university,beijing 100084,china 1. National Laboratory for CFD Hypervelocity Aerodynamics Institute China Aerodynamics Research and Development Center 621000 Mianyang China 2. department of Engineering Mechanics Tsinghua University 100084 Beijing China

The gas-kinetic unified algorithm using Boltzmann model equation have been extended and developed to solve the micro-scale gas flows in Poiseuille-like micro-channels from Micro-Electro-Mechanical Systems (MEMS). The numerical modeling of the gas kinetic boundary conditions suitable for micro-scale gas flows is presented. To test the present method, the classical Couette flows with various Knudsen numbers, the gas flows from short microchannels like plane Poiseuille and the pressure-driven gas flows in two-dimensional short microchannels have been simulated and compared with the approximate solutions of the Boltzmann equation, the related DSMC results, the modified N-S solutions with slip-flow boundary theory, the gas-kinetic BGK-Burnett solutions and the experimental data. The comparisons show that the present gas-kinetic numerical algorithm using the mesoscopic Boltzmann simplified velocity distribution function equation can effectively simulate and reveal the gas flows in microchannels. The numerical experience indicates that this method may be a powerful tool in the numerical simulation of micro-scale gas flows from MEMS.

关键词： Boltzmann model equation, discrete velocity ordinate method, finite-difference scheme, Couette flow, Poiseuille flow, gas flow in short-microchannel.

Information flow and controlling in regularization inversion of quantitative remote sensing

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第1期48卷 74-83页

作者： YANG Hua, XU Wangli, ZHAO Hongrui, CHEN Xue & WANG Jindi Research Center for Remote Sensing and GIS, School of Geography, beijing normal university, State Key Laboratory of Remote Sensing Science, beijing Key Laboratory for Remote Sensing of Environment and Digital Cities, beijing 1.0875, china department of Mathematics, beijing normal university, beijing 1.0875, china 1. Research Center for Remote Sensing and GIS School of Geography Beijing Normal University State Key Laboratory of Remote Sensing Science Beijing Key Laboratory for Remote Sensing of Environment and Digital Cities 100875 Beijing China 2. department of Mathematics Beijing Normal University 100875 Beijing China

In order to minimize uncertainty of the inversed parameters to the largest extent by making full use of the limited information in remote sensing data, it is necessary to understand what the information flow in quantitative remote sensing model inversion is, thus control the information flow. Aiming at this, the paper takes the linear kernel-driven model inversion as an example. At first, the information flow in different inversion methods is calculated and analyzed, then the effect of information flow controlled by multi-stage inversion strategy is studied, finally, an information matrix based on USM is defined to control information flow in inversion. It shows that using Shannon entropy decrease of the inversed parameters can express information flow more properly. Changing the weight of a priori knowledge in inversion or fixing parameters and partitioning datasets in multi-stage inversion strategy can control information flow. In regularization inversion of remote sensing, information matrix based on USM may be a better tool for quantitatively controlling information flow.

关键词： regularization inversion, information flow, Shannon entropy decrease, information matrix.

Complex variable method for plane elasticity of icosahedral quasicrystals and elliptic notch problem

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,Mechanics & astronomy) 2008年第7期51卷 773-780页

作者： LI LianHe1,2 & FAN TianYou1 1 department of Physics, beijing Institute of Technology, beijing 100081, china 2 College of Mathematics Science, Inner Mongolia normal university, Hohhot 010022, china department of Physics Beijing Institute of Technology Beijing 100081 China College of Mathematics Science Inner Mongolia Normal University Hohhot 010022 China

The complex variable method for the plane elasticity theory of icosahedral quasicrystals is developed. Based on the general solution obtained previously, complex representations of stress and displacement components of phonon and phason fields in the quasicrystals are given. With the help of conformal transformation, an analytic solution for the elliptic notch problem of the material is presented. The solution of the Griffith crack problem can be observed as a special case of the results. The stress intensity factor and energy release rate of the crack are also obtained.

关键词： icosahedral quasicrystals plane elasticity elliptic notch complex variable method

Characterization for commutators of n-dimensional fractional Hardy operators

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2007年第10期50卷 1418-1426页

作者： Zun-wei FU~(1,2) Zong-guang LIU~3 Shan-zhen LU~(1+) Hong-bin WANG~3 ~1 School of Mathematical Sciences,beijing normal university,beijing 1.0875,china ~2.department of Mathematics,Linyi normal university,Linyi 276005,china ~3 department of Mathematics,china university of Mining and Technology (beijing),beijing 100083,china 1. School of Mathematical Sciences Beijing Normal University Beijing 100875 China 2. department of Mathematics Linyi Normal University Linyi 276005 China 3. department of Mathematics China University of Mining and Technology (Beijing) Beijing 100083 China

In this paper,it was proved that the commutator H_(β,b)generated by an n-dimensional fractional Hardy operator and a locally integrable function b is bounded from L^(p1)(R^n)to L^(p2)(R^n)if and only if b is a CMO(R^... 详细信息

关键词： n-dimensional fractional Hardy operator, commutator, C(M)O function, homogeneous Herz space

Homology classes that can be represented by embedded spheres in rational surfaces

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2004年第3期47卷 431-439页

作者： GAO Hongzhu GUO Ren department of Mathematics,beijing normal university, beijing 1.0875,china 1. department of Mathematics Beijing Normal University 100875 Beijing China

The problem of embedding spheres in rational surfaces CP 2#n $\overline {CP} $ 2 is studied. For homology classes u = (b 1 + k, b 2,...,b n) with positive self-intersection numbers, a necessary and sufficient conditio... 详细信息

关键词： four manifold embedded sphere self-intersection number

Lookback time as a test for f(R) gravity in the Palatini approach

在线全文

学校读者我要写书评

暂无评论

Research in astronomy and Astrophysics 2011年第11期11卷 1257-1265页

作者： Zhong-Xu Zhai and Wen-Biao Liu department of Physics, Institute of Theoretical Physics, beijing normal university, beijing 1.0875, china department of Physics Institute of Theoretical Physics Beijing Normal University Beijing 100875 China

We use the recently released data of lookback time (LT)-redshift relation, the cosmic microwave background shift parameter and the baryon acoustic oscillation measurements to constrain cosmological parameters of f (R) gravity in the Palatini formalism by considering the f (R) form of type (a) f (R) = R β/Rn and (b) f (R) = R + α ln R β. Under the assumption of a Friedmann-Robertson-Walker universe, we achieved the best fitting results of the free parameters (Ωm0, n) for (a) and (Ωm0, α) for (b). We find that current LT data can provide interesting and effective constraints on gravity models. Compared with other data, the LT constraints favor a smaller value of the non-relativistic matter energy density.

关键词： cosmology cosmic microwave background

Effects of enhancing p21^(waf1) on proliferation and expression of G1 cyclins and CDKs in human breast cancer cells

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第16期44卷 1489-1493页

作者： SANG Jianli, WANG Yongchao and YE Yingjiang1. Laboratory of Cell Biology , department of Biology , beijing normal university , beijing 1.0875 , china 2. The Second Hospital, beijing Medical university, beijing 100044, china Laboratory of Cell Biology Department of Biology Beging Normal University Beijing China The Second Hospital Beijing Medical University Beijing China

The cyclin-dependent kinase inhibitor p21( waf1/cip1/sdi1) is an important negative regulator in control of cell cycle. Its functions of inhibiting cancer cell growth and its effects on expression of Gl phase cyclins and related CDKs are a worthy topic for study. The plasmid expressing p2l with high level was transformed to human breast cancer cells, and the expression of p2l in cells was enhanced, then the cell growth rate, anchorage-independent growth and tu-morigenecity were tested, at the same time the expression levels of cyclinD1, CDK4,

关键词： p21waf1 breast cancer cell cyclin CDK.

A Remark on Multilinear Oscillatory Singular Integrals

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2000年第4期16卷 655-668页

作者： Shanzhen Lu Dunyan Yan department of Mathematics, beijing normal university, beijing 1.0875. P. R. china department of Mathematics Beijing Normal University Beijing 100875 P. R. China

In this paper we study multilinear oscillatory singular integrals with rough kernel and give a criterion of certain boundedness for this kind of operator

关键词： Multilinear oscillatory integrals Calderon-Zygmund kernel BLO space