Global Existence of Positive Periodic Solutions for a Distributed Delay Competition Model

By using the continuation theorem of Mawhin's coincidence degree theory, a sufficient condition is derived for the existence of positive periodic solutions for a distributed delay competition modelwhere ri and r2 are continuous w-periodic functions in R+=[0,∞) with ,ai,ci(i =1,2) are positive continuous w-periodic functions in R+=[0,∞),bi (i = 1,2) is nonnegative continuous w-periodic function in R+=[0,∞), w and T are positive constants. Ki,Lt ∈ C([-T,0], (01 88)) and Ki(s)ds = 1,ds - 1. i = 1,2. Some known results are improved and extended.     

关于中立型时滞模型的周期正解

本文利用拓扑度理论和某些新技巧,研究了一类中立型时滞模型N′(t)=N(t)［a(t)-b(t)N(t-τ(t))-c(t)N′(t-τ(t))］周期正解的存在性,得到了一些新结果,解决了一个公开问题,并推广、改进了一些已知文献的结果,同时也改正了文［3］中微分运算的错误和定理2.     

一类具分布时滞的退化微分系统的周期解

本文利用重合度理论讨论一类具分布时滞的退化微分系统的周期解存在性,给出了周期解的存在条件.     

中立型时滞模型的周期正解

本文通过使用某些新技巧，研究了中立型时滞模型Ｎ＇（ｔ）＝Ｎ（ｔ）［ａ（ｔ）－－β（ｔ）－ｂ（ｔ）Ｎ（ｔ－Ｔ（ｔ））－Ｃ（ｔ）Ｎ＇（ｔ－Ｔ（ｔ））］周期正解的存在性，解决了文［１］中的一个公开问题，并改正了文［２］中的错误。     

Periodic solution of a neutral delay competition model

1.IntroductionNeutraldelayffereatialequationsinpopulationdynamicshavebeenstudiedextensivelyforthep88tfewyears.However,onlyafewpapersll--5]havebeenpublishedontheexistencesofperiodicsolutionsoftheneutraldelaypopulationmodels.In[6,7],Kuangproposedtoinve...     

Periodic Solutions for a Damped Rayleigh Beam Model with Time Delay

Vibrations of a beam can be described as an Euler-Bernoulli beam,or as a Rayleigh beam or as a Timoshenko beam. In this paper, we establish the existence of periodic solutions in time for a damped Rayleigh beam model with time delay, which is treated as a bifurcation parameter. The main proof is based on a Lyapunov-Schmidt reduction together with the classical implicit function theorem. Moreover, we give a sufficient condition for a direction of bifurcation.     

具有分布滞量的微分系统的周期解和全局吸引性

利用重合度理论中的延拓定理和Ｌｙａｐｕｎｏｖ泛函方法讨论一类具有分布滞量的微分系统狓（狋）＝ 犃（狋）狓（狋）＋∫０－狉犳（狋,狊,狓狋＋狊））ｄ狊的周期解的存在性和全局吸引性,得到了便于应用的新结果．     

具投放的中立型时滞竞争扩散系统正周期解的存在性

利用Nussbaum 度理论建立了具投放的中立型时滞竞争扩散系统 x′₁(t)=x₁(t)[a₁(t)-b₁(t)x₁(t)-c₁(t)y(t) ]+D₁(t)[x₂(t)-x₁(t)]+S₁(t), x′₂(t)=x₂(t)[a₂(t)-b₂(t)x₂(t)]+D₂(t)[x₁(t)-x₂(t) ]+S₂(t), y′(t)=y(t)[a₃(t)-b₃(t)y(t)-α(t)y(t-τ₁(t))-β(t) ∫⁰_τ k(s)y(t+s)ds -γ(t)y’(t-τ₂(t))-c₃(t)x₁(t)]. 存在正周期解的一个充分条件.     

具有时滞的高维周期系统的周期解

本文研究具有时滞的高维周期系统x'(t)=A(t,x(t))x(t)+f(t,x(t-τ))与x'(t)=gradG(x(t))+f(t,x(t-τ))的周期解,利用重合度理论,得到保证其存在周期解的充分条件.作为应用,建立了一类对数种群模型周期正解的存在性.     

一类高维时滞微分方程的周期解

本文考虑高维时滞微分方程ｘ′（ｔ）＝Ａ（ｔ,ｘ（ｔ））ｘ（ｔ）＋ｆ（ｔ,ｘ（ｔ－ｒ（ｔ）））其中（ｔ,ｘ）∈Ｒ^ｎ,Ａ（ｔ,ｘ）是ｎ×ｎ连续矩阵,ｆ（ｔ,ｘ）是ｎ维连续向量,ｒ（ｔ）是时间依赖的滞量,应用不动点定理,在确定的条件下,证明了该系统的周期解的存在性与唯一性     

一类高阶中立型泛函微分方程周期解的存在性

研究了一类高阶非线性中立型泛函微分方程x~((2n))(t)+cx~((2n))(t-τ)+f(x)x′+bx(t)+g(x(t-σ))=p(t)周期解的存在性,利用分析技巧结合重合度理论给出了该方程存在周期解的充分性定理.     

时滞Rayleigh方程周期解问题

利用Mahwin重合度拓展定理研究了一类具时滞Rayleigh方程x″(t)+f(x′(t))+g∫0-rx(t+s)dm(s)=p(t)周期解问题,得到了周期解存在的一组充分条件.     

无穷时滞Liénard方程的周期解(英文)

讨论具有无穷时滞Liénard型方程x+(?²F(x))/(?x²)x+g(t,x_t)=p(t)的周期解问题, 利用重合度理论得到了周期解存在的充分条件.     

Weighted Pseudo Almost Periodic Solutions for a Class of Hematopoiesis Model with Time-Varying Delay

In this paper, firstly, a notion of a class of generalized weighted pseudo al-most periodic function is introduced, then we investigate some basic and essential properties of the space that consists of these functions. Finally, we study the exis-tence of weighted pseudo almost periodic solutions to hematopoiesis model with time-varying delay.     

具有连续时滞和比率型功能反应的竞争系统的正周期解的存在性

本文利用重合度理论中的延拓定理讨论了具有连续时滞和比率型功能反应的非自治扩散竞争系统的正周期解的存在性,得到了正周期解存在的充分条件。     

具无穷时滞竞争扩散系统周期解的唯一性

研究了一类具有无穷时滞竞争扩散模型的周期解问题,采用了上下解的方法,获得了周期解的存在唯一性,并给出了解的渐近性态.     

一类多滞量周期扰动非线性系统的周期解

研究一类具有多个滞量的周期扰动非线性系统的T周期解.利用拓扑度的方法得到了系统存在T周期解的充分条件.作为应用,证明了具有滞后的单种群对数模型在一定条件下存在正周期解.     

Periodic Solutions of a Delayed Predator-Prey Model with Stage Structure for Prey

A periodic predator-prey model with stage structure for prey and time delays due to negative feed-back and gestation of predator is proposed.By using Gaines and Mawhin's continuation theorem of coincidencedegree theory,sufficient conditions are derived for the existence of positive periodic solutions to the proposedmodel.Numerical simulations are presented to illustrate the feasibility of our main result.     

一个非线性时滞偏微分方程种群模型的稳定性与周期性

讨论了一个具有年龄结构非线性非自治时滞偏微分方程种群模型解的渐近性态,得到了零解稳定以及周期解存在的充分条件.