检索结果-南通市图书馆

Full automorphism group of the generalized symplectic graph

在线全文

学校读者我要写书评

暂无评论

science China Mathematics 2013年第7期56卷 1509-1520页

作者： ZENG LiWei CHAI Zhao FENG RongQuan MA ChangLi lmam School of Mathematical Sciences Peking University science China Press College of Mathematics and Information science Hebei Normal University

Let Fq be a finite field of odd characteristic, m, v the integers with 1 ≤ m ≤ v and K a 2v × 2v nonsingular alternate matrix over Fq. In this paper, the generalized symplectic graph GSp2v（q, m） relative to K over Fq is introduced. It is the graph with m-dimensional totally isotropic subspaces of the 2v-dimensional symplectic space Fq（2v） as its vertices and two vertices P and Q are adjacent if and only if the rank of PKQw is 1 and the dimension of P ∩ Q is m - 1. It is proved that the full automorphism group of the graph GSp2v（q, m） is the projective semilinear symplectic group P∑p（2v, q）.

关键词： generalized symplectic graph automorphism projective generalized symplectic group totally isotropic subspace generalized dual polar graph

Nonconforming finite element methods on quadrilateral meshes

在线全文

学校读者我要写书评

暂无评论

science China Mathematics 2013年第12期56卷 2599-2614页

作者： HU Jun ZHANG ShangYou lmam and school of mathematical sciences Peking University Department of mathematical sciences University of DelawareNewark DE 19716 USA

It is well known that it is comparatively difficult to design nonconforming finite elements on quadri- lateral meshes by using Gauss-Legendre points on each edge of triangulations. One reason lies in that these de- grees of freedom associated with these Gauss-Legendre points are not all linearly independent for usual expected polynomial spaces, which explains why only several lower order nonconforming quadrilateral finite elements can be found in literature. The present paper proposes two families of nonconforming finite elements of any odd order and one family of nonconforming finite elements of any even order on quadrilateral meshes. Degrees of freedom are given for these elements, which are proved to be well-defined for their corresponding shape function spaces in a unifying way. These elements generalize three lower order nonconforming finite elements on quadri- laterals to any order. In addition, these nonconforming finite element spaces are shown to be full spaces which is somehow not discussed for nonconforming finite elements in literature before.

关键词： nonconforming finite element rectangle

ABSOLUTE CONTINUITIES OF EXIT MEASURES AND TOTAL WEIGHTED OCCUPATION TIME MEASURES FOR SUPER-α-STABLE PROCESSES

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2006年第2期26卷 358-370页

作者：张静任艳霞 College of science and Technology Inner Mongolia University Hohhot 010020China School of Mathematical SciencesPeking UniversityBeijing 100871China lmam school of mathematical sciences Peking University Beijing 100871China

Suppose X is a super-α-stable process in R^d, （0 〈 α〈 2）, whose branching rate function is dr, and branching mechanism is of the form ψ（z） = z^1＋β （0 〈0 〈β ≤1）. Let Xγ and Yγ denote the exit measure and the total weighted occupation time measure of X in a bounded smooth domain D, respectively. The absolute continuities of Xγ and Yγ are discussed.

关键词： Super-α-stable process absolute continuity exit measure total weighted occupation time measure

Investigation of the surface orientation influence on 10-nm double gate GaSb nMOSFETs

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2017年第4期26卷 383-387页

作者：邸绍岩沈磊伦志远常鹏鹰赵凯卢朓杜刚刘晓彦 Institute of Microelectronics Peking University school of Information and Communication Beijing Information Science and Technology University CAPT HEDPSIFSA Collaborative Innovation Center of Ministry of EducationLMAM & School of Mathematical SciencesPeking University

The performance of double gate GaSb nMOSFETs with surface orientations of（100） and（111） are compared by deterministically solving the time-dependent Boltzmann transport equation（BTE）.Results show that the on-state current of the device with（111） surface orientation is almost three times larger than the（100） case due to the higher injection ***,the scattering rate of the（111） device is slightly lower than that of the（100） device.

关键词： Boltzmann transport equation GaSb surface orientation double gate

A NOTE ON THE NONCONFORMING FINITE ELEMENTS FOR ELLIPTIC PROBLEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2011年第2期29卷 215-226页

作者： Boran Gao Shuo Zhang Ming Wang school of mathematical sciences Peking University Beijing 100871 China ICMSEC AMSS Chinese Academy of Science Beijing 100190 PR China lmam School of Mathematical Sciences Peking University Beijing 100871 China

In this paper, a class of rectangular finite elements for 2m-th-oder elliptic boundary value problems in n-dimension （m, n ≥1） is proposed in a canonical fashion, which includes the （2m - 1）-th Hermite interpolation element （n = 1）, the n-linear finite element （m = 1） and the Adini element （m = 2）. A nonconforming triangular finite element for the plate bending problem, with convergent order （O（h2）, is also proposed.

关键词： Nonconforming finite element Elliptic boundary value problem Plate bending problem.

New feature extraction in gene expression data for tumor classification

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Progress in Natural science:Materials International 2005年第9期15卷 861-864页

作者： HE Renya, CHENG Qiansheng**, WU Lianwen and YUAN Kehong(lmam, school of mathematical sciences, Institute of Molecular Medicine, Peking University, Beijing 100871, China) lmam School of Mathematical Sciences Institute of Molecular Medicine Peking University Beijing 100871 China

Using gene expression data to discriminate tumor from the normal ones is apowerful method. However, it is sometimes difficult because the gene expression data are in highdimension and the object number of the data sets is very small. The key technique is to find a newgene expression profiling that can provide understanding and insight into tumor related cellularprocesses. In this paper, we propose a new feature extraction method based on variance to the centerof the class and employ the supportvector machine to recognize the gene data either normal ortumor. Two tumor data sets are used to demonstrate the effectiveness of our methods. The resultsshow that the performance has been significantly improved.

关键词： tumor classification support vector machine (SVM) bioinformatics featureextraction gene expression

Numerical Simulation of Fluid Membranes in Two-Dimensional Space

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2008年第4期3卷 794-821页

作者： Peng Song Dan Hu Pingwen Zhang lmam and school of mathematical sciences Peking UniversityBeijing 100871China.

The membrane’s dynamics is very important for cells.A membrane in 2-dimensional space can be seen as an incompressible closed curve in a plane or a cylindrical surface in 3-dimensional *** this paper,we design a second-order accurate numerical algorithm to simulate the shape transformation of the *** the algorithm,we use the tangent angles to present the curve and avoid the difficulties from the constraint of curve’s incompressible condition.A lot of interesting phenomena are *** of them are very like the life processes of cells,such as exocytosis and ***,we can see the relation between two dynamic models *** last,considering the influence of the inner incompressible fluids partially,we add a constraint:the area circled by the membrane maintain *** numerical results show the dynamic motions of a curve remaining its local arc length and inner area constant.

关键词： Director model of the membrane reduced model osmotic pressure spontaneous curvature constraint of the area.

Oblique Derivative Problems for Second Order Nonlinear Equations of Mixed Type with Degenerate Hyperbolic Curve

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2011年第10期27卷 2051-2064页

作者： Guo Chun WEN lmam School of Mathematical Sciences Peking University Beijing 100871 P. R. China

The present paper deals with oblique derivative problems for second order nonlinear equa- tions of mixed type with degenerate hyperbolic curve, which include the Tricomi problem as a special case. Firstly the formulation of the problems for the equations is given, next the representation and estimates of solutions for the above problems are obtained, finally the existence of solutions for the problems is proved by the successive iteration of solutions of the equations and the fixed-point princi- ple. In this paper, we use the complex analytic method, namely the new partial derivative notations, elliptic complex functions in the elliptic domain and hyperbolic complex functions in the hyperbolic domain are introduced, such that the second order equations of mixed type with degenerate curve are reduced to the first order mixed complex equations with singular coefficients, and then the advantage of complex analytic method can be applied.

关键词： Oblique derivative problems nonlinear mixed equations degenerate hyperbolic curve

Littlewood Paley g-function on the Heisenberg Group

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2006年第1期22卷 95-100页

作者： He Ping LIU Rui Qin MA lmam School of Mathematical Sciences Peking University Beijing 100871 P. R. China

We consider the g-function related to a class of radial functions which gives a characterization of the L^p-norm of a function on the Heisenberg group.

关键词： Heisenberg group g-function