一类捕食和被捕食系统的持久性

本文获得了一类捕食和被捕食系统持久性的充分条件 ,推广了文 [1]的部分结果     

一类二阶微分方程的振动性

本文考虑二阶既具正系数又具负系数的时滞微分方程(x|¨)(t)+p(t)x(t-τ)-q(t)x(t-σ)=0 (*)(其中 p(t)、q(t)是[f_o,+∝)上的非负连续函数,τ、σ是正实数)的振动性。获得了方程(*)的所有有界解振动的充分性判据;以及在 p(t)、q(t)均为常数的情况下,获得了方程(1)的所有有界解振动的一些必要条件和充分必要条件。     

ASYMPTOTIC BEHAVIOR OF SOLUTIONS OF NONLINEAR DELAY DIFFERENTIAL EQUATIONS

Sufficient conditions are established for the asymptotic behavior of solutionsof nonlinear delay differential equations x′(t)+sum from i=1 to m(pi(t)x(t-т_i))=F(t,x_t),t≥0where 0<т_1<т_2<…<т_m≤r,pi∈C([0,∞)),i=1,2,…,m,F∈C([0,∞)×C_0,R).C_0=C([-r,0],R)equipped with the sup norm ||·|| forsome r>0. A new result is established, some known results are improved.     

PERIODIC SOLUTIONS OF PLANAR SYSTEM WITH SIX DELAYS

In this paper we obtain some sufficient conditions for the existence of non-constant periodic solutions of the following planar system with six delaysOur approach is based on the continuation theorem of the coincidence degree.     

GLOBAL ATTRACTIVITY IN A MODEL OF BOBWHITE QUAIL WITH DELAY

1IlltroductionInl99o,MiltinandB.lairl1]raisedadifferenceequationasapopulationmodelforthegrowthofthebobwhitequailpopulationofnorthernWisconsin.Inl994,Ladas,G.proposedthefollowingopenproblem[']:"(a)Investigatetheboundedness,persistence,permanence,oscillation,periodicity,andglobalattractivity;(b)ExtendEq.(*)byintroducingdelaysintothemodel,andinvestigatethedelayedequation.".Inl996,TangHeng-shengandOuChun-hua[3]considereditsglobalattrac-tivity,partlyansweredaboveopenproblem(a).Inl999,byintrodu…     

中立型时滞微分方程振动的充分条件的计算机算法

文 [2 ]研究了一般的具有正负系数的一阶中立型时滞微分方程的振动性 ,建立了一切解振动的充要条件 .本文就其特殊情况进行了计算机算法的研究 ,得到了依据方程的系数经过计算机处理就能判定方程 ( 1)的振动性 .     

脉冲时滞差分方程的振动性

讨论脉冲时滞差分方程xn+1- xn +pnxn-2 =0 ,n≥ 0 ,n≠ nkxnk+1- xnk =bkxnk,k =1,2 ,3,…给出了方程所有解振动的充分条件     

具反馈控制的多滞量Logistic增长模型的全局吸引性

本文研究具反馈控制的多滞量Logistic增长模型的全局吸引性.所得结果改善并推广了一些已知定理.     

中立型量滞微分方程振动的充分条件的计算机算法

[2]研究了一般的具有正负系数的一阶中立型时滞微分方程的振动性，建立了一切解振动的充要条件。本就其特殊情况进行了计算机算法的研究，得到了依据方程的系数经过计算机处理就能判定方程⑴的振动性。     

GLOBAL ATTRACTIVITY IN DELAYED HOPFIELD NEURAL NETWORK MODEL WITH VARIABLE COEFFICIENTS AND DELAYS

1 Introduction' In paper [1], Hopfield first proposed neural network model for n neurons;with an electrical circuit implementation. Even since, there has been increasing interest in the potential application of the dynamics of artificial neuralnetworks in signal and image processing, see, for example, [2]--[5], they havestudied system (1.1) and the delayed systemwhere all ci ) Ri, Ti j ? h, T are constants.The global attractivity of system (1.l) or (1.2) is of great importance forboth practi…