周期参数扰动的T混沌系统周期轨道分析

本文研究了一类周期参数扰动的T混沌系统的周期轨道问题.利用次谐波Melnikov方法,获得了具有广义Hamilton结构的周期参数扰动的慢变系统的振荡周期轨道和旋转周期轨道.     

一类二维流场模型的周期解与浑沌解的共存性*

本文研究Kelvin-Stuart猫眼流在周期扰动下的动力学行为,运用Melnikov方法确定出振动型周期轨产生偶数阶次谐分枝、旋转型周期轨产生任意阶次谐分枝的条件,并进一步发现周期解与浑沌解共存的复杂现象.     

非线性振动系统的异宿轨道分叉,次谐分叉和混沌

在参数激励与强迫激励联合作用下具有van der Pol阻尼的非线性振动系统,其动态行为是非常复杂的.本文利用Melnikov方法研究了这类系统的异宿轨道分叉、次谐分叉和混沌.对于各种不同的共振情况,系统将经过无限次奇阶次谐分叉产生Smale马蹄而进入混沌状态.最后我们利用数值计算方法研究了这类系统的混沌运动.所得结果揭示了一些新的现象.     

周期时间制约的非Hamliton可积Kolmogorov系统的混沌与次谐波

本文研究一类非Hamilton可积的Kolmogorov生态系统的周期激励模型，应用Melnikov方法，得到了该系统存在混沌与次谐分枝的某些充分条件。     

高间Melnikov方法

本文把原有Melnikov方法推广到高阶情况.找到了二阶次谐Melnikov函数表达式,并且证明了在一定条件下可以用二阶次谐Melnikov函数来判定系统的次谐或超次谐的存在.     

非 Hamilton 系统的次谐分叉和马蹄

目前,浑沌理论引起了人们广泛的兴趣,已有一系列理论的结果.判断浑沌的发生通常是检验横截同宿点的存在.最近,严寅、钱敏证明了:对于异宿点,若具有横截 n-环,则同样存在 Smal 马蹄.对于二维的 Hamilton 系统受扰动后,Melnikov 给出了判定 Poincaré映射横截同宿点或异宿点存在的解析工具.本文讨论非 Hamilton 系统:=uv,(?)=1-u~2-v~2在适当的扰动下存在 Smal 马蹄,同时,用 Melnikov 方法讨论了次谐分叉及次谐分叉与马蹄的关系.     

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.     

奇摄动下的共振不变环面分支

本文研究高维退化系统在小扰动下的动力学行为,在共振的情况下,利用延拓的方法,讨论了扰动系统不变环面的保存性,并利用推广的Melnikov函数、横截性理论讨论了同宿于不变环面的横截同宿轨道存在的条件,推广和改进了一些文献的结果.     

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.     

奇摄动下的共振不变环面分支

本文研究高维退化系统在小扰动下的动力学行为,在共振的情况下,利用延拓的方法,讨论了扰动 系统不变环面的保存性,并利用推广的Melnikov函数、横截性理论讨论了同宿于不变环面的横截同宿 轨道存在的条件,推广和改进了一些文献的结果.     

Multipulse Orbits in the Motion of Flexible Spinning Discs

Summary. The global dynamics of flexible spinning discs are studied. The discs studied are parametrically excited in their spin rate, and have imperfections that cause symmetry-breaking. After determining the equations of motion in a suitable form, the energy-phase method is employed to show the existence of chaotic dynamics by identifying multipulse jumping orbits in the perturbed phase space. We provide restrictions on the damping, forcing, and symmetry-breaking parameters in order for these complicated dynamics to occur. The dissipative version of the energy-phase method predicts a wider range of values for which chaotic dynamics occurs than the traditional Melnikov method. The results are then discussed in terms of the physical motion of the spinning disc system. The multipulse orbits are manifested in the physical system as a shifting between two different nodal configurations of the disc. When the motion is chaotic, an observer will see a random jumping between the two nodal configurations of the disc. Received February 7, 2000; accepted November 18, 2001     

Homoclinic orbits for a perturbed quintic-cubic nonlinear Schrdinger equation

IntroductionIn recent years, there have been extensive studies on the existence of homoclinic orbit5 fOrnear integrable Hamiltonbo partial fferential equations, which are closely related to chaosI1--7].In this work, we consider a perturbed quintic-cubic nonlinear Schr5dinger (NLS) equationwhere q is 27-Periodic and even in x, D is a bounded dissipative operator and is assumed totake the formDq = --aq + jBqfor posititre constants cr and J. Here B is a Fourier truncation of the differentia…     

Homoclinic orbits for a perturbed quintic-cubic nonlinear Schrödinger equation

The existence of homoclinic orbits for a perturbed cubic-quintic nonlinear Schrödinger equation with even periodic boundary conditions under the generalized parameters conditions is established. We combined geometric singular perturbation theory, Melnikov analysis, and integrable theory to prove the persistence of homoclinic orbits.     

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     

Homoclinic orbits and chaos in discretized perturbed NLS systems: Part I. Homoclinic orbits

Summary The existence of homocliic orbits, for a finite-difference discretized form of a damped and driven perturbation of the focusing nonlinear Schroedinger equation under even periodic boundary conditions, is established. More specifically, for external parameters on a codimension 1 submanifold, the existence of homoclinic orbits is established through an argument which combines Melnikov analysis with a geometric singular perturbation theory and a purely geometric argument (called the “second measurement” in the paper). The geometric singular perturbation theory deals with persistence of invariant manifolds and fibration of the persistent invariant manifolds. The approximate location of the codimension 1 submanifold of parameters is calculated. (This is the material in Part I.) Then, in a neighborhood of these homoclinic orbits, the existence of “Smale horseshoes” and the corresponding symbolic dynamics are established in Part II [21].     

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.     

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.     

The necessary and sufficient conditions for the existence of periodic orbits in a Lotka-Volterra system

By extending Darboux method to three dimension, we present necessary and sufficient conditions for the existence of periodic orbits in three species Lotka-Volterra systems with the same intrinsic growth rates. Therefore, all the published sufficient or necessary conditions for the existence of periodic orbits of the system are included in our results. Furthermore, we prove the stability of periodic orbits. Hopf bifurcation is shown for the emergence of periodic orbits and new phenomenon is presented: at critical values, each equilibrium are surrounded by either equilibria or periodic orbits.