具无限时滞的周期系统的持久性与正周期解

本文利用比较定理,控制收敛定理和积分平均的方法,讨论一类具有无限时滞的非自治,非卷积的捕食者-食饵系统的一致持久性和正周期解.     

周期外力作用下一类非保守系统的周期解

一、引言考虑非保守系统(?) A(t,x,(?))(?) B_x=P(t,x,(?)).(1)其中 x=col(x~1,…,x~n)∈R~n,A 是 n 阶实对称函数阵,B 是 n×n 常阵,A,P 连续且关于 t以2π为周期.本文主要研究方程(1)的2π周期解的存在性.我们知道二阶方程在周期解问题的研究中占有特殊重要的地位,这是因为工程技术和力学中的许多问题,例如非线性振荡问题,都可以用二阶常微分方程来描述.这些描述工程和力学问题的方程通常可以分成两类:一类是具有阻尼项的非保守系统(例如方程(1));另一类是没有阻尼项的保守系统.对于如下的保守系统     

一类积分微分包含的周期解

研究了一类积分微分包含的周期解,利用Kakutani不动点定理和Tichonoff不动点定理给出了凸和非凸两种情形下周期解存在的充分条件.     

具有阶段结构和周期投放的非自治单种系统的周期解

研究一类带周期投放的非自治阶段结构单种群模型,利用泛函微分方程的单调和凹算子理论,得到系统存在一个全局吸引正周期的充分条件。     

一类凝血系统的周期解

本文对一类含扩散项和非齐次项的凝血系统，应用Galerkin方法和Leray-Schauder不动点定理证明了时间周期解的存在性。     

四阶非线性周期系统周期解的存在唯一性

本文利用Liapunov函数方法,研究了一类具有缓变系数的四阶非线性非自治周期系统的周期解的存在唯一性及其渐近稳定性.我们得到了保证这些系统存在唯一稳定周期解的充分条件,并对系数的缓变范围作了较为精确的估计.     

抽象泛函微分方程的权伪概周期解

本文利用算子半群理论和Banach不动点定理研究了一类具非局部条件的抽象泛函微分方程权伪概周期解的存在唯一性,所得结论拓展了已有结果.     

周期吸附系统的分布混沌

由一个紧致度量空间X以及连续映射f:X→X所组成的偶对(X,f)称之为一个动力系统.若存在f的不动点p以及另一周期点q,使得对于任一非空开集U(?)X,都有∪_(n=0)~∞f~n(U)含有p和q,则称(X,f)是一个周期吸附系统,其中f~i表示f的i次迭代.本文指出:若(X,f)是一个周期吸附系统并且X是自密的,则存在一个f的分布混沌集D,使得D与每一非空开集之交都包含着一个Cantor集.     

一类非自治系统的周期解

本文运用重合度理论研究一类非自治非线性系统的周期解问题，得到一些有关存在性，唯一性和稳定性的新结果。     

具有脉冲收获的捕食系统的周期解

考虑了一类具有阶段结构和脉冲收获的捕食模型.讨论了解的非负性和有界性.利用重合度定理,得到了正周期解存在的充分条件.     

高维时滞周期的Kolmogorov型系统的正周期解

本文应用Ｂａｎａｃｈ空间中的Ｈｏｒｎ不动点得到了高维时滞的周期Ｋｏｌｍｏｇｏｒｏｖ型生态系统的正周期解存在性定理,作为这个定理的应用,讨论了几类时滞的周期ＬｏｔｋａＶｏｌｔｅｒｒａ型系统的正周期解的存在性问题,建立了新的实用的判别准则。     

一种广义周期Besov类的多元周期多项式样条逼近

本文证明多元多项式周期样条空间是某些多元周期光滑函数类的关于Kolmogorov n-宽度的弱渐近极子空间．给出了广义周期Besov类的一种推广，得到了空间元素的一种表示定理，不仅给出了一种多元周期多项式样条算子．而且证明了所得的结果．     

ON THE EXISTENCE OF PERIODIC SOLUTION OF HIGHER ORDER PERIODIC SYSTEM

ＯＮＴＨＥＥＸＩＳＴＥＮＣＥＯＦＰＥＲＩＯＤＩＣＳＯＬＵＴＩＯＮＯＦＨＩＧＨＥＲＯＲＤＥＲＰＥＲＩＯＤＩＣＳＹＳＴＥＭ（王全义）华侨大学，邮编：３６２０１１ＷａｎｇＱｕａｎｙｉ（ＨｕａｑｉａｏＵｎｉｖｅｒｓｉｔｙ）Ａｂｓｔｒａｃｔ：Ｉｎｔｈｉｓｐａｐ...     

PERIODIC SOLUTIONS AND ALMOST PERIODIC SOLUTIONS OF A NONAUTONOMOUS PREDATOR-PREY SYSTEM WITH STAGE-STRUCTURE AND DELAY

In this paper, by using the comparing theorem, Razumikhin-type theorem and V-function method, we consider a nonautonomous predator-prey system with stage-structure and time-delay. We get the sufficient conditions for the uniform persistence and the solutions global attractivity of this system. For a periodic system, we obtain the existence and uniqueness of a positive periodic solution of this system. For an almost periodic system, we prove the existence and the uniform asymptotic stability of the almost periodic solutions of this system.     

PERIODIC AND ALMOST PERIODIC SOLUTIONS OF A CERTAIN INFINITE DELAY INTEGRAL EQUATION

In this paper,by using successive approximation method and fixed-point theorem,we discuss a class of infinite delay integral equation and obtain some sufficient conditions which guarantee the existence and uniqueness of the peri- odic and almost periodic solutions of the system.     

PERIODIC SOLUTION FOR DIFFUSIVE PREDATOR-PREY PATCH SYSTEMS WITH TIME DELAY AND PERIODIC STOCKING

In this paper, a three species difFusive predator-prey modei with functional response and periodic stocking is studied, where all parameters are time depen-dent. By using new theorem of coincidence degree theory, the existence of a positive periodic solution for this system is established.     

EXISTENCE AND UNIQUENESS OF PERIODIC SOLUTIONS TO A HIGHER DIMENSIONAL PERIODIC SYSTEM WITH DELAY

In this paper, using fixed point theorem, we discuss a higher dimensional nonautonomous periodic system with delay and give some suffcient criteria for the existence and uniqueness of periodic solution. Our results extend and improve some results in previous researches.     

THE EXISTENCE OF ALMOST PERIODIC SOLUTION TO A CLASS OF ALMOST PERIODIC DIFFERENTIAL SYSTEM

By means of the fixed point theorem and exponential dichotomy, in this paper we investigate the existence of almost periodic solutions to a class of n-dimensional almost periodic systems, which is more general than the systems in [1-2]. We generalize and improve some results in [3].     

EXISTENCE OF POSITIVE PERIODIC SOLUTION FOR A DELAYED PERIODIC PREDATOR-PREY MODEL OF IVLEV TYPE

A periodic coefficients predator-prey system of Ivlev type with both discrete and continuous time delay is investigated. A sufficient condition of the existence of positive periodic solution is established for the system by using the continuation theorem of coincidence degree theory.     

EXISTENCE AND STABILITY OF PERIODIC SOLUTIONS OF DELAYED BAM NEURAL NETWORKS WITH PERIODIC COEFFICIENTS

In this paper, we study the BAM neural networks with variable coefficients and delays. By using the Banach fixed point theorem and constructing suitable Lyapunov function, we obtain some sufficient conditions ensuring the existence, uniqueness and global stability of periodic solution. These results are helpful to design global exponential stable BAM networks and periodic oscillatory BAM networks.