A new perturbation solution for systems with strong quadratic and cubic nonlinearities

The new perturbation algorithm combining the method of multiple scales (MS) and Lindstedt–Poincare techniques is applied to an equation with quadratic and cubic nonlinearities. Approximate analytical solutions are found using the classical MS method and the new method. Both solutions are contrasted with the direct numerical solutions of the original equation. For the case of strong nonlinearities, solutions of the new method are in good agreement with the numerical results, whereas the amplitude and frequency estimations of classical MS yield high errors. For strongly nonlinear systems, exact periods match well with the new technique while there are large discrepancies between the exact and classical MS periods. Copyright © 2009 John Wiley & Sons, Ltd.     

粒子在 Hénon-Heiles势中的逃逸动力学模拟

利用庞加莱截面和相空间轨迹方法对粒子在Hénon-Heiles势中的逃逸动力学进行了模拟.粒子的动力学性质敏感地依赖于粒子的能量.数值计算表明当能量很小时,粒子的运动是规则的;随着能量的增加,粒子的运动开始出现混沌.当能量增加到鞍点能Es时,几乎所有的相空间轨迹都是混沌的.当粒子的能量E>Es,粒子可以越过势阱发生逃逸.对于给定的大于Es的能量, 我们画出了粒子的逃逸-时间曲线和逃逸轨迹.我们的研究对于研究混沌传输和逃逸动力学具有一定的参考价值.     

渐近时间周期系统

本文证明了渐近时间周期系统的Ｐｏｉｎｃａｒｅ映射的极限集是极限系统的Ｐｏｉｎｃａｒｅ映射的不变集。     

一种确定非线性振子多个共存周期解的数值方法

提出一种简洁高效数值方法，用以确定周期激励下非线性振子的多个共存周期响应。这是一种基于Ｐｏｉｎｃａｒé映射和二维自治系统奇点分类的几何方法，可在Ｐｏｉｎｃａｒé截面上得出多个周期运动的分布情况和类型。文中二个算例证实了该方法的有效性。     

Liénard方程Poincaré分岔极限环的唯一性

本文利用隐函数定理和一阶Mel'nikov函数,对Lienard方程Poincare分岔极 限环的唯一性进行了探讨, 同时也对闭轨的不存在性进行了分析,给出了若干判据. 通过对一阶Mel'nikov函数进行变形, 引入了新的判定函数, 由此得到了更为简单的 判定条件.     

DEGENERATED HOMOCLINIC BIFURCATIONS WITH HIGHER DIMENSIONS

91.IntroductionandHypothesesInrecelltyears)withthedevelopmelltofnonlinearscienceandthedeepstudyof~icphenomena,anincreasinglylargenUInberofpapersared~edtothebifurcationProblemsofhomocliulcandheterocbocorbitsinhighdhansionalspace(see11--14]).Duetothedifficultyencountered,uofortunately,onlyafew(e.g.[1,13,14])areconcernedwiththeperiodicorbitsbifulcatedfromsingularloops.Papers[1,131discussedtheProblemofthehomoclinicloOPbifurcationinhighdimensionwithcodimension2,thatis,thesystemhasresonanteigenVa…     

半整权模形式Fonrier系数的两个注记

对于ｆ（ｚ）＝∑α＿ｎｅ（ｎｚ）∈Ｓ＿ｋ（г＿０（Ｎ）），Ｈ．Ｉｗａｎｉｅｃ￣［２］证明了，其中ｎ为无平方因子正整数．在本文中我们将推广这个结果．     

POINCARE BIFURCATIONS IN THEQUADRATIC SYSTEMS

From[11,weknowthatthequadraticsystems(QSforabbreviation)whichmayhavelimitcyclescanbewrittenintheform:where6,l,m,n)al5areconsideredasparameters.Foragivenunperturbedplanarsystemwithafamilyofclosedorbits,whilemostofthemarebrokenundersmallperturbationssomemaybepreservedtobecomeisolatedclosedorbits(licitcycles).ThiscaseiscalledthePoincarebifurcation(PBforabbreviation).TherearesomeworksonPBoftheQS,see[4],[5],[6],I7]etc.WenowconsiderthePBoftheQSwiththeform(l),andassumethattheoriginOisthecenterp…