检索结果-南通市图书馆

N-Soliron-like Solution of Ito Equation

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2004年第11期 641-644页

作者： zhang yi~(1,2,) chen deng-yuan~2 ~1department of mathematics,zhejiang normal university,jinhua 3.1.04,china ~2department of mathematics,shanghai university,shanghai 200436,china department of mathematics，zhejiang normal university，jinhua 3.1.04，china department of mathematics，shanghai university，shanghai 200436，china department of mathematics，shanghai university，shanghai 200436，china

By using the extended Hirota’s method,the N-soliton-like solution of the Ito equation is ***-thermore,we also investSgate the soliton-like solution interaction and find singularity.

关键词： soliton-like solution Ito equation Hirota method

Evaluation on cutting performance of novel PDC cutter for pipe jacking machine

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Underground Space 2024年第1期14卷 34-52页

作者： Long-Chuan deng yi-Xiang yuan Xiao-Zhao Li Qian-Wei Zhuang Chi zhang yi-Wei chen School of Earth Sciences and Engineering Nanjing UniversityNanjingJiangsu 210023China shanghai Tunnel Engineering Co.Ltd. Shanghai 200232China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhouJiangsu 221116China School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China

It is inevitable to cut reinforced concrete(RC)appeared in cross passage of city metro by cutting tools when constructing in densely populated *** previous cutters employed to cut RC are insufficient and easily damaged,so a new polycrystalline diamond compact(PDC)cutter is used to solve this *** on the theoretical analysis of cutting mechanism,both circular and tapered PDC cutters with cutting edge angle of 90and negative front rack angle of 10are used to cut *** peeling and breaking patterns of cutting concrete are proposed,the nodular and grainy chips are the preferred modes in cutting steel *** LS-DYNA is employed to investigate the cutting performance in *** simulation results show that the average and peak cutting forces increase with the growth of penetration depth,cutting speed,and roundness,and subsequently the recommended penetration depth less than 1.2 mm is obtained to cut RC due to the existence of steel ***,the linear cutting platform is adopted to investigate the force ability and damage state of PDC *** is concluded that the cutting force increases abruptly and fluctuates heavily when cutting the coarse *** patterns occurred in both numerical and experimental results are generally ***,the steel bar is pulled out and the PDC cutter is damaged at the penetration depth of 0.8 mm,while a good cut occurs at the penetration depth of 0.3 *** tapered PDC cutter with a relatively low cutting force is prone to be broken compared with circular PDC *** is suggested that the circular PDC cutter at the penetration depth of 0.3 mm should be used to cut RC in practical engineering.

关键词： PDC cutter RC Pipe jacking machine Linear cutting tests Damage and wear LS-DYNA

DERIVATIONS ON DIFFERENTIAL OPERATOR ALGEBRA AND WEYL ALGEBRA

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 1996年第2期17卷 199-212页

作者： chen CAOYU department of mathematics, shanghai normal university, shanghai 200234, china. shanghai normal UNIV DEPT MATHSHANGHAI 200034PEOPLES R CHINA

Let L be an n-dimensional nilpotent Lie algebra with a basis {x1,…,xn}, and every xiacts as a locally nilpotent derivation on algebra A. This paper shows that there exists a setof derivations {y1,…,yn} on U(L) such that (A#U(L))#k[yi,…,yn] is isomorphic to theWeyl algebra An(A). The author also uses the derivations to obtain a necessary and sufficientcondition for a finite dimensional Lie algebra to be nilpotent.

关键词： Crossed porduct Smash product Derivation Nilpotent Lie algebra Weyl algebra

SEMI-DEFINITE RELAXATION ALGORITHM FOR SINGLE MACHINE SCHEDULING WITH CONTROLLABLE PROCESSING TIMES

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 2005年第1期26卷 153-158页

作者： chenFENG zhangLIANSHENG departmentofmathematics ShanghaiUniversityShanghai200436China／／DepartmentofIndustrialEngineeringandManagementShanghaiJiaotongUniversityShanghai200030China. departmentofmathematics ShanghaiUniversityShanghai200436China

The authors present a semi-definite relaxation algorithm for the scheduling problem with controllable times on a single machine. Their approach shows how to relate this problem with the maximum vertex-cover problem with kernel constraints (MKVC).The established relationship enables to transfer the approximate solutions of MKVCinto the approximate solutions for the scheduling problem. Then, they show how to obtain an integer approximate solution for MKVC based on the semi-definite relaxation and randomized rounding technique.

关键词： Scheduling with controllable times Semi-definite programming Approximation algorithm

Fredholm operators in Toeplitz algebras associated with discrete abelian groups

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第14期43卷 1175-1179页

作者： XU Qingxiang 1 and chen Xiaoman 2 1. department of mathematics, shanghai normal university, shanghai 200234, china 2. Laboratory of mathematics for Nonlinear Sciences and Institute of mathematics, Fudan university, shanghai 200433, china department of mathematics Shanghai Normal University Shanghai China Laboratory of mathematics for Nonlinear Sciences and Institute of mathematics Fudan University Shanghai China

The locally finite below sets are introduced and the Fredholm operators in Toeplitz algebras associated with discrete abelian groups are studied.

关键词： discrete abelian group quasi_ordered group Toeplitz operator Fredholm operator.

The geodetic numbers of graphs and digraphs

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2007年第8期50卷 1163-1172页

作者： Chang-hong LU~(1,2) 1 department of mathematics,East china normal university,shanghai 200062,china 2 Institute of Theoretical Computing,East china Narnal university,shanghai 200062,china 1. department of mathematics East China Normal University Shanghai 200062 China 2. Institute of Theoretical Computing East China Narnal University Shanghai 200062 China

For every two vertices u and v in a graph G, a u-v geodesic is a shortest path between u and v. Let I(u, v) denote the set of all vertices lying on a u-v geodesic. For a vertex subset S, let I(S) denote the union of all I(u, v) for u, v ∈ S. The geodetic number g(G) of a graph G is the minimum cardinality of a set S with I(S) = V (G). For a digraph D, there is analogous terminology for the geodetic number g(D). The geodetic spectrum of a graph G, denoted by S(G), is the set of geodetic numbers of all orientations of graph G. The lower geodetic number is g ?(G) = minS(G) and the upper geodetic number is g +(G) = maxS(G). The main purpose of this paper is to study the relations among g(G), g ?(G) and g +(G) for connected graphs G. In addition, a sufficient and necessary condition for the equality of g(G) and g(G × K 2) is presented, which improves a result of Chartrand, Harary and zhang.

关键词： convex set digraph distance geodesic geodetic number 05C12 05C20

On the generalized Busemann-Petty problem

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2007年第8期50卷 1103-1116页

作者： Song-jun L~(1,2+) Gang-song LENG~1 1.College of mathematics and Computer Science,Chongqing normal university,Chongqin 400047,china 2.department of mathematics,shanghai university,shanghai 200444,china College of mathematics Computer Science Chongqing Normal University Chongqin 400047 China department of mathematics Shanghai University Shanghai 200444 China

The generalized Busemann-Petty problem asks whether the origin-symmetric convex bodies in ? n with a larger volume of all i-dimensional sections necessarily have a larger volume. As proved by Bourgain and zhang, the answer to this question is negative if i > 3. The problem is still open for i = 2, 3. In this article we prove two specific affirmative answers to the generalized Busemann-Petty problem if the body with a smaller i-dimensional volume belongs to given classes. Our results generalize zhang’s specific affirmative answer to the generalized Busemann-Petty problem.

关键词： star body cross i-section dual mixed volume Radon transform 52A30 52A40

SCHWARZ-PICK ESTIMATES FOR BOUNDED HOLOMORPHIC FUNCTIONS ON CLASSICAL DOMAINS

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2011年第4期31卷 1377-1382页

作者：刘洋陈志华 department of mathematics Zhejiang Normal University department of mathematics Tongji University

In this paper, Schwarz-Pick estimates for high order Fr′echet derivatives of bounded holomorphic functions on three kinds of classical domains are presented. We generalize the early work on Schwarz-Pick estimates of ... 详细信息

关键词： Schwarz-Pick estimate holomorphic functions classical domains

Rose solutions with three petals for planar 4-body problems

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2010年第12期53卷 3085-3094页

作者： deng ChunHua 1,2 , zhang ShiQing 1, & ZHOU Qing 3 1 Yangtze Center of mathematics and College of mathematics, Sichuan university, chengdu 610064, china 2 Faculty of mathematics and Physics, Huaiyin Institute of Technology, Huai’an 223001, china 3 department of mathematics, East china normal university, shanghai 200062, china 1. Yangtze Center of mathematics and College of mathematics Sichuan University Chengdu 610064 China2. Faculty of Mathematics and Physics Huaiyin Institute of Technology Huai’an 223001 China3. Department of Mathematics East China Normal University Shanghai 200062 China

For planar Newtonian 4-body problems with equal masses, we use variational methods to prove the existence of a non-collision periodic choreography solution such that all bodies move on a rose-type curve with three pet... 详细信息

关键词： 4-body problems with Newtonian potentials rose solutions with three petals winding numbers variational minimization methods