Melnikov向量与退化情形下的横截异宿轨道

利用指数二分性和泛函分析方法,我们研究了当未扰动系统不具有异宿流形的退化异宿分支.我们利用Melnikov型向量给出了系统在退化情形下的横截异宿轨道存在的充分条件.     

指数二分性与退化情形下的异宿分支

利用指数型二分性理论,研究了较高退化程度下的异宿分支理论;给出了一个能确定系统在退化情形下横截同、异宿轨道存在性的Melnikov向量;提供了一个处理高维退化情形下横截同、异宿轨道存在性的泛函分析方法.     

指数型二分性,Melnikov函数和异宿轨道

本文用不同于Ｐａｌｍｅｒ＾［２］的方法，讨论了非自治微分方程存在异宿轨道的条件。得到了已知文献中不同的一个Ｍｅｌｍｉｋｏｖ型的函数。     

Melnikov向量函数和异宿流形

用指数二分法,横截性理论和推广的Melnikov方法,来研究具有较高退化程度的异宿、同宿轨在扰动下保存和横截的条件,结果推广、包含和改进了许多重要文献的结果。     

伴随奇点分支的退化异宿轨道的保存和横截性

本文应用指数三分性和不变流形的局部几何表示方法,给出异宿流形上的轨道当两个奇点经历超;临界分支和摄动时保存和横截的条件．     

Melnikov型向量函数和奇异轨道的主法向

本文应用指数二分法和横截性理论研究具有较高退化程度的奇异轨道在自治扰动下保存的条件及其几何意义,并给出了由异宿(同宿)轨道组成的2维柱面(环面)上在摄动下唯一保存的奇异轨道的具体例子。     

指数二分性与奇异摄动系统的横戳异宿轨道

本文研究奇异摄动系统的横截异宿轨道的存在性,利用指数二分性理论和Liapunov－Schmidt方法,获得了判断奇异摄动系统存在横截异宿轨道的Melnikov型函数,因而推广了一些文献的结果．     

奇摄动问题中的异宿流形

应用指数2分性和横截性理论等动力系统方法来处理奇摄动问题中的同宿、异宿轨道的存在性和横截性问题，对具有较高退化程度的所谓奇异同宿轨道和奇异异宿轨道（见定义1.1）在奇摄动下何时变为同宿、异宿轨道给出了用Melnikov向量来刻划的判据和实例．     

自治奇摄动系统的同、异宿轨道

利用指数二分性理论和泛函分析方法来处理第一变分方程在R上有多于一个非平凡有界解下的奇摄动系统的同宿轨道分支问题.利用此方法我们给出了判断奇摄动系统在退化情形下存在同、异宿轨道的Melnikov向量函数并给出了存在同宿轨道的参数估计范围.     

指数二分性与高阶Melnikov函数

本文利用指数二分性理论和Liapunov－Schmidt方法，研究了当Melnikov函数具有高阶零点时的横截同宿轨道的存在性，得到了一个所谓的高阶Melnikov函数     

Transversal homoclinic orbits for higher dimensional difference equations

In this paper, we use the functional analytic method (theory of exponential dichotomies and Liapunov-Schmidt method) to study the homoclinic bifurcations of higher dimensional difference equations in a degenerate case. We obtain a Melnikov vector mapping for difference equations with the help of which the existence of transversal homoclinic orbits can be detected.     

Melnikov方法和圆型平面限制性三体问题的横截同宿研究*

本文对由两自由度近可积哈密顿系统经非正则变换而得到的,具有高阶不动点的非哈密顿系统给出了判别横截同宿轨和横截异宿轨存在性的两条判据。对原二体质量比很小时近可积圆型平面限制性三体问题,采用本文判据证明存在横截同宿轨,从而存在横截同宿穿插现象;还在一定假设下证明了存在横截异宿轨;并给出了全局定性相图。     

Transversal Homoclinic Orbits in the Collinear Restricted Three-Body Problem

Using the perturbation method of Melnikov, we prove in a simple way the existence of transversal homoclinic points in the collinear restricted three-body problem. As a consequence we can embed a Bernoulli shift on a suitable cross section of the flow, showing easily that this problem possesses chaotic dynamics.     

超临界情形的Melnikov函数及应用

该文具体推导了三阶Melnikov函数的积分表达，解决了电机工程中提出的一类系统（见[5]），当参数时的超临界（一阶、二阶Melnikov函数恒为零）的情形下，系统的稳定流形与不稳定流形的相对位置的确定问题．并通过环面上的VanderPol方程，对[2]与[4]所给的二阶Melnikov函数的表达式进行了比较，结果发现[2]所给的平面自治系统的二阶，n阶表达式均是错的.该文在最后作了纠正.     

Numerical Method for Homoclinic and Heteroclinic Orbits of Neuron Models

A twisted heteroclinic cycle was proved to exist more than twenty- five years ago for the reaction-diffusion FitzHugh-Nagumo equations in their traveling wave moving frame. The result implies the existence of infinitely many traveling front waves and infinitely many traveling back waves for the system. However efforts to numerically render the twisted cycle were not fruit- ful for the main reason that such orbits are structurally unstable. Presented here is a bisectional search method for the primary types of traveling wave solu- tions for the type of bistable reaction-diffusion systems the FitzHugh-Nagumo equations represent. The algorithm converges at a geometric rate and the wave speed can be approximated to significant precision in principle. The method is then applied for a recently obtained axon model with the conclusion that twisted heteroclinic cycle maybe more of a theoretical artifact.     

Transversal Heteroclinic Bifurcation in Hybrid Systems with Application to Linked Rocking Blocks

In this paper, we study heteroclinic bifurcation and the appearance of chaos in time-perturbed piecewise smooth hybrid systems with discontinuities on finitely many switching manifolds. The unperturbed system has a heteroclinic orbit connecting hyperbolic saddles of the unperturbed system that crosses every switching manifold transversally, possibly multiple times. By applying a functional analytical method, we obtain a set of Melnikov functions whose zeros correspond to the occurrence of chaos of the system. As an application, we present an example of quasiperiodically excited piecewise smooth system with impacts formed by two linked rocking blocks.     

一类含有参数和有理奇性哈密顿系统的同宿与异宿轨道

研究一类含有两个参数和有理奇性平面哈密顿系统的同宿与异宿轨道,该问题来源于一个关于聚合物流体剪切流动特性的研究．借助常微定性理论和不变流形分析的方法,文中给出了系统存在同宿与异宿轨道的条件,并通过数值计算检验了所得理论结果。     

Numerical Computation of Connecting Orbits in Delay Differential Equations

We discuss the numerical computation of homoclinic and heteroclinic orbits in delay differential equations. Such connecting orbits are approximated using projection boundary conditions, which involve the stable and unstable manifolds of a steady state solution. The stable manifold of a steady state solution of a delay differential equation (DDE) is infinite-dimensional, a problem which we circumvent by reformulating the end conditions using a special bilinear form. The resulting boundary value problem is solved using a collocation method. We demonstrate results, showing homoclinic orbits in a model for neural activity and travelling wave solutions to the delayed Hodgkin–Huxley equation. Our numerical tests indicate convergence behaviour that corresponds to known theoretical results for ODEs and periodic boundary value problems for DDEs.