电子束聚焦系统模型的周期性

行波管电子束聚焦理论在物理、生物、电子等科学领域中的应用非常广泛.为了控制电子束的运动轨迹,使其有效地聚焦目标,利用重合度理论中的延拓定理对电子束聚焦系统数学模型的周期解的存在性进行了研究,得到了该模型在一定条件下存在周期正解的结论.同时分析了模型系数取值范围的可行性,对行波管的设计具有一定的指导意义.     

BIFURCATIONS OF TRAVELLING WAVE SOLUTIONS FOR THE GENERALIZED DODD-BULLOUGH-MIKHAILOV EQUATION

In this paper, the generalized Dodd-Bullough-Mikhailov equation is studied. The existence of periodic wave and unbounded wave solutions is proved by using the method of bifurcation theory of dynamical systems. Under different parametric conditions, various sufficient conditions to guarantee the existence of the above solutions are given.Some exact explicit parametric representations of the above travelling solutions are obtained.     

Jaulent-Miodek方程的行波解分支

利用平面动力系统分支理论研究了耦合的Jaulent-Miodek方程的孤立波及周期波的存在性,求出了分支参数集．在给定的参数条件下,得到了该方程光滑孤立波解及周期行波解的所有可能的显式表达式．     

广义特殊Tzitzeica-Dodd-Bullough类型方程的行波解

本文研究了广义特殊Tzitzeica-Dodd-Bullough类型方程,利用动力系统分支理论方法,证明该方程存在周期行波解,无界行波解和破切波解,并求出了一些用参数表示的显示精确行波解.     

一类广义Burgers-Huxley方程的解与其分支

运用平面动力系统分支理论和可积性判定方法,研究了一类广义Burgers-Huxley方程,首先通过新的算法计算奇点量,解决了其可积性问题,然后进行平衡点类型分析,并讨论了在不同的参数条件下的相图与分支类型,利用Maple软件绘出分支相图,最后讨论了各种行波解的存在性及方程的精确解.     

一类滞后型非自治的捕食者-食饵系统的周期解

本文研究了一类滞后型三种群捕食者-食饵Lotka-Volterra系统.利用重合度理论 建立了这类系统正周期解的存在性判据.     

具有时滞和基于比率的两种群捕食者-食饵扩散系统的周期解

本文研究了一类具有时滞和基于比率的两种群捕食者—食饵扩散系统，利用重合度理论建立了这类系统正周期解的存在性判据。     

一个曲面波方程的精确解

Abstract. Some exact travelling wave solutions and rational travelling wave solutions of a sur-face wave equation in a convecting fluid are given in this paper.     

BIFURCATIONS AND NEW EXACT TRAVELLING WAVE SOLUTIONS OF THE COUPLED NONLINEAR SCHRDINGER-KdV EQUATIONS

By using the method of dynamical system, the exact travelling wave solutions of the coupled nonlinear Schrdinger-KdV equations are studied. Based on this method, all phase portraits of the system in the parametric space are given. All possible bounded travelling wave solutions such as solitary wave solutions and periodic travelling wave solutions are obtained. With the aid of Maple software, the numerical simulations are conducted for solitary wave solutions and periodic travelling wave solutions to the coupled nonlinear Schrdinger-KdV equations. The results show that the presented findings improve the related previous conclusions.     

一类非线性波方程的光滑与非光滑行波解

讨论了一类偏微分方程的行波解。该方程的行波方程对应于一个平面三次多项式系统,因而可将行波解的研究化为对平面系统所定义的相轨线的拓扑分类研究。应用平面动力系统理论在三参数空间内作定性分析,首先获得三次多项式系统的完整拓扑分类,再将相平面分析的结果返回到非线性波解u(ξ) 。考虑到解关于变量ξ=x-ct在“奇线”近旁的不连续性,可得到各种光滑与非光滑行波的存在条件。     

Explicit periodic travelling waves for a discrete lambda–omega reaction–diffusion system

In 1973, Kopell and Howard introduced a λ–ω reaction–diffusion system and found an explicit family of periodic travelling wave solutions lying on circles with radius less than 1. Since λ–ω systems represent universal models for studying chemical processes, and onset of turbulent behaviour, etc., explicit solutions of λ–ω systems with delays or discrete λ–ω systems can be of further help when the only method for obtaining other solutions is through numerical computation. There are now much investigations of various λ–ω systems. However, it is of interest to note that none attempts to find explicit travelling wave solutions. In this paper, we investigate the existence of explicit solutions for the simplest Euler scheme of a λ–ω system with delays or advancements which is described as a coupled pair of partial difference equations. We are able to provide necessary as well as sufficient conditions for the existence of numerical periodic travelling wave solutions. Additionally, we also provide some examples to show that our explicit solutions are qualitatively different from those found by Kopell and Howard and hence they may be of interests for specialists in the area of reaction–diffusion systems.     

具有偏差变元的捕食者-食饵系统全局周期解的存在性

利用重合度理论中的延拓定理讨论了一类具有偏差变元的捕食者-食饵系统全局周期解的存在性,得到了一些新结果。     

n维变时滞Lotka-Volterra系统周期正解的存在性

基于非线性常微分方程泛函分析研究了一类变时滞n维非自治Lotka-Volterra系统周期正解的存在性,利用重合度理论建立了这类系统周期正解的存在性判据,得到了相应的充分性条件.同时对系统的持久性问题也作了分析,得到了相应的定理.最后,通过计算机仿真,对文中论述周期正解的存在性进行了佐证.