检索结果-南通市图书馆

Codimension 3 nonresonant bifurcations of homoclinic orbits with two inclination flips

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2005年第2期48卷 248-260页

作者： SHUI Shuliang & ZHU Deming College of mathematics and Physics, Zhejiang normal {2., Jinhua 32.004, china department of mathematics, East china normal {2., Shanghai 2.0062. china 1. College of mathematics and Physics Zhejiang Normal University 321004 Jinhua China 2. department of mathematics East China Normal University 200062 Shanghai China

Homoclinic bifurcations in four-dimensional vector fields are investigated by setting up a local coordinate near a homoclinic orbit. This homoclinic orbit is principal but its stable and unstable foliations take inclination flip. The existence, nonexistence, and uniqueness of the 1-homoclinic orbit and 1-periodic orbit are studied. The existence of the two-fold 1-periodic orbit and three-fold 1 -periodic orbit are also obtained. It is indicated that the number of periodic orbits bifurcated from this kind of homoclinic orbits depends heavily on the strength of the inclination flip.

关键词： bifurcation, homoclinic orbit, non-resonance, inclination flip, 1-periodic orbit.

在线全文

学校读者我要写书评

暂无评论

Saturated models

Chinese Science Bulletin 1998年第7期43卷 562-564页

作者： CHEN Guolong department of mathematics, Beijing {2. university, Beijing 100875, china department of mathematics Beijing Normal University Beijing China

An equivalent description of saturated models is given, and some properties of countable saturated models, almost saturated models and full models are discussed. New proofs of two important theorems of the related doc... 详细信息

关键词： almost saturated model full model power type.

NUMERICAL SIMULATION OF THE DISPERSION IN OSCILLATING FLOWS WITH REVERSIBLE AND IRREVERSIBLE WALL REACTIONS

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2009年第4期21卷 482-490页

作者： ZHANG Dao-xiang LU Zhi-ming LIU Yu-lu NG Chiu-On Shanghai Institute of Applied mathematics and Mechanics Shanghai University Shanghai 200072 China College of mathematics and Computer Science Anhui Normal University Wuhu 241000 China department of Mechanical Engineering The University of Hong Kong Hong Kong China

This is a study on the mass transport of a solute or contaminant in oscillating flows through a circular tube with a reactive wall layer. The reaction consists of a reversible component due to phase exchange between the flowing fluid and the wall layer, and an irreversible component due to absorption into the wall. The short-time dispersion characteristics are numerically investigated, incorporating the coupling effects between the flow oscillation, sorption kinetics, and retardation due to phase partitioning. The effects of various dimensionless parameters e.g., Da （the Damkoehler number）, α （phase partitioning number）, F （dimensionless absorption number）, and δ （dimensionless Stokes boundary layer number） on dispersion are discussed. In particular, it is found that there exist trinal peaks of the breakthrough curves in some cases.

关键词： dispersion flow oscillation wall reactions

AN INVARIANCE OF CDF EQUATION

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of mathematics,Series B 1994年第2期15卷 241-246页

作者： TIAN CHOU(department of Matehematics,university of Science and Technology of{2., Hefei 2.0064, anhui,{2.) UNIV SCI & TECHNOL china DEPT MATHHEFEI 230026PEOPLES R CHINA

This paper presents a new invariance for the CDF equation. Using this invariance, the author obtains some new solutions of CDF equation.

关键词： CDF equation Invariance MKdV equation.

Short cycle structures for graphs on surfaces and an open problem of Mohar and Thomassen

在线全文

学校读者我要写书评

暂无评论

Science china mathematics 2006年第2期49卷 212-224页

作者： REN Han & DENG Mo department of mathematics, East{2. normal university, Shanghai 2.0062.{2. College of mathematics & Information Science, Northwest normal university, Lanzhou 730070,{2. 1. department of mathematics East China Normal University Shanghai 200062 China 2. College of mathematics & Information Science Northwest Normal University Lanzhou 730070 China

In this paper we investigate cycle base structures of a (weighted) graph and show that much information of short cycles is contained in an MCB (i.e., minimum cycle base). After setting up a Hall type theorem for base-transformation, we give a sufficient and necessary condition for a cycle base to be an MCB. Furthermore, we show that the structure of MCB in a (weighted)graph is unique. The property is also true for those having a longest length (although much work has been down in evaluating MCB, little is known for those having a longest length). We use those methods to find out some unknown properties for short cycles sharing particular properties in (unweighted) graphs. As applications, we determine the structures of short cycles in an embedded graph and show that there exist polynomially bounded algorithms in finding a shortest contractible cycle and a shortest two-sided cycle provided such cycles exist. Those answer an open problem of B. Mohar and C. Thomassen.

关键词： cycle base facial cycle graph embedding.

Lp integrability of trigonometric series with special varying coefficients

在线全文

学校读者我要写书评

暂无评论

Applied mathematics:A Journal of Chinese Universities 2009年第4期24卷 402-410页

作者： WEI Bao-rong department of mathematics,Hangzhou {2. university,Zhejiang 310036,china department of mathematics Hangzhou Normal University Zhejiang 310036 China

Very recently,Yu,Le and Zhou introduced the so called Δ*B1 and Δ*B2.conditions,which are generalizations of the monotone *** applying these two new conditions,the author essentially generalizes the classical results of Chen on the necessary and sufficient conditions of the Lp integrability of trigonometric *** fact,the present paper gives the first result on the necessary and sufficient conditions of the Lp integrability of trigonometric series,where coefficients may have diffierent signs.

关键词： Lp integrability trigonometric series special varying coefficients

METHOD OF NONCONFORMING MIXED FINITE ELEMENT FOR SECOND ORDER ELLIPTIC PROBLEMS METHOD OF NONCONFORMING MIXED FINITE ELEMENT FOR SECOND ORDER ELLIPTIC PROBLEMS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Computational mathematics 2000年第5期18卷 449-456页

作者： Zhen-dong Luo (department of mathematics, Capital {2. university, Beijing 100057, china) 首都师范大学北京 100037

In this paper, the method of non-conforming mixed finite element for second order elliptic problems is discussed and a format of real optimal order for the lowest order error estimate.

关键词： Non-conforming mixed finite element Error estimate Second order elliptic problems.

Recovery of functions via their irregular sampling values

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1998年第4期43卷 268-271页

作者： FANG Gensun department of mathematics, Beijing {2. university, Beijing 100875, china department of mathematics Lkijing Normal University Beijing China

It is proved that if a function can be completely reconstructed by tempered splines which satisfy the real Kiesz basis condition as the degree of spline goes to infinity, then the function is band limited.

关键词： band limited function cardinal splines irregular sampling.

Quasirational dynamic system

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第14期45卷 1277-1279页

作者： SUN Daochun & YANG Lo1. department of mathematics, South{2. normal university, Guangzhou 510631,{2. 2. Institute of mathematics, Academy of mathematics and System Sciences, Chinese Academy of Sciences, Beijing 100080,{2. department of mathematics South China Normal University Guangzhou China Institute of mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China

Using the iterations of quasirational mappings, the theorems on dynamic system are generalized to the quasirational dynamic system. Some different results are also obtained.

关键词： quasirational mapping dynamic system covering surface.