具有阶段结构且食饵有避难所的模型分析

研究了捕食者具有阶段结构且食饵有避难所的非自治捕食系统.利用Lyapunov函数方法得到了系统持续生存的条件,以及在一定条件下存在唯一全局渐进稳定的周期正解.对于更广泛的概周期现象,也得到了存在唯一全局渐进稳定的概周期正解的充分条件.     

Global positive periodic solutions of age-dependent competing systems

This paper is to investigate positive periodic solutions of a biological system composed of two competing species. The existence and uniqueness of nonnegative solutions to the model for a set of given vital rates and initial distribution are treated and the contractive property of the solutions explored. Based on these results, some simple conditions for the global existence of positive periodic orbits are established by means of Horn’s asymptotic fixed point theorem.     

一类具第三类功能反应且食饵具有避难所的捕食系统的分析

研究了一类具第三类功能反应且食饵具有避难所的非自治捕食系统.利用Lyapunov函数方法得到了系统持续生存的条件,以及在一定条件下,系统存在全局渐进稳定的周期正解.对于更广泛的概周期现象,也得到了存在唯一全局渐进稳定的概周期正解的充分条件.     

一类具有收获率的脉冲Lotka-Volterra竞争合作系统的八个正概周期解

研究了一类具有收获率的脉冲Lotka-Volterra竞争合作系统的正概周期解.通过利用重合度理论延拓定理、概周期理论和不等式分析技巧,获得了系统至少存在8个正概周期解的充分条件,推广和改进了早期文献的相关结果.     

Periodic solutions of neutral functional differential systems with two parameters

In this paper, we consider certain first-order neutral differential system with two parameters. Some existence results of one positive periodic solution and two positive periodic solutions and nonexistence of positive periodic solutions are obtained. Our approach is based on Krasnoselskii fixed point theorem in cones.     

DYNAMICS OF THE NONAUTONOMOUS SCHONER MODEL WITH FEEDBACK CONTROL AND DIFFUSION

This paper consider a nonautonomous schoner model with feedback control and diffusion. It is shown that the system can be made persistence. Then the existence and the uniqueness of the positive solutions and positive almost periodic solutions for corresponding periodic system and almost periodic system are also discussed.     

一类具有收获率和扩散的时滞阶段结构捕食系统的多重正周期解

该文研究了一类具有收获率和扩散的时滞阶段结构捕食系统周期解存在性问题,利用重合度理论中的延拓定理,通过一些分析技巧, 获得了该系统至少存在四个正周期解的充分条件.     

Multiplicity of positive periodic solutions to a generalized delayed predator–prey system with stocking

In this paper, by using the continuation theorem of coincidence degree theory, the existence of multiple positive periodic solutions for a generalized delayed predator–prey system with stocking is established. When our result is applied to a delayed predator–prey system with nonmonotonic functional response and stocking, we establish the sufficient condition for the existence of multiple positive periodic solutions for the system.     

一类具有比率和单调功能反应的中立型捕食系统的正周期解

研究了一类具有比率和单调功能反应的中立型捕食系统.通过利用重合度理论获得了其正周期解存在性的充分条件,推广和改进了已有文献的相关结果.     

一类具有Holling Ⅲ型功能性反应的捕食者-食饵系统的周期解的存在性

利用重合度理论中的延拓定理研究带有开发利用项的具有Holling Ⅲ型功能性反应的捕食者-食饵系统,得到了两个正周期解存在的充分条件,得到了一些新的结果.     

Positive periodic solutions for a neutral impulsive delayed Lotka–Volterra competition system with the effect of toxic substance

Based on the coincidence degree theory and its related continuation theorem as well as some a priori estimates, we explore the existence of periodic solutions with strictly positive components of a neutral delayed Lotka–Volterra competitive system with impulse. Easily verifiable sufficient criteria are established for the existence of positive periodic solution for the neutral impulsive system. When the results reduce to neutral system without impulse, they generalize the results in Yang and Cao [Positive periodic solutions of neutral Lotka–Volterra system with periodic delays, Appl. Math. Comput. 149 (2004) 661–687].     

非自治Kolmogorov竞争系统的严格正解

In this paper, the existence of strictly positive solutions for N species normutonomous Kolmogorov competition systems is studied. By applying the Schauder‘s flxed pointtheorem some new sufficient conditions are established. In particular, for the almost periodicsystem, tile existence of strictly positive almost periodic solutiorts is obtained, Some previousresults are improved and generalized.     

含参数泛函微分方程概周期正解的存在性

研究了一类含参数泛函微分方程概周期正解的存在性问题.结合有界性及渐近概周期性获得了系统存在概周期正解的几组充分条件,并将结果应用于几类种群动力学模型,分别获得了系统在概周期环境下存在概周期解的一组充分条件.     

A periodic predator–prey-chain system with impulsive perturbation

A periodic predator–prey-chain system with impulsive effects is considered. By using the global results of Rabinowitz and standard techniques of bifurcation theory, the existence of its trivial, semi-trivial and nontrivial positive periodic solutions is obtained. It is shown that the nontrivial positive periodic solution for such a system may be bifurcated from an unstable semi-trivial periodic solution. Furthermore, the stability of these periodic solutions is studied.     

Uniqueness of periodic solutions of a nonautonomous density-dependent predator–prey system

In this present paper, we investigate the uniqueness of periodic solutions of a nonautonomous density-dependent and ratio-dependent predator–prey system, where not only the prey density dependence but also the predator density dependence are considered, such that the studied predator–prey system conforms to the realistically biological environment. We start with a sufficient condition for the permanence of the system and then construct a weaker sufficient condition by introducing a specific set, denoted as Γ. Based on this Γ and the Brouwer fixed-point theorem, we obtain the existence condition of positive periodic solutions. Moreover, since the uniqueness of positive periodic solutions can be ensured by global attractiveness, we alternatively introduce a sufficient condition for global attractiveness. Similarly, we also provide a sufficient condition for the uniqueness of non-negative periodic solutions.     

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.     

一类带反馈控制的非自治离散竞争系统概周期解的动力学性质

本文利用差分方程的比较原理以及构造国合适的Lyapunov函数,讨论了一类带有反馈控制的非自治离散竞争系统的持久性和概周期解,给出了存在正概周期解的几个充分条件.最后给出一个数值例子验证了本文主要结果的有效性.     

Analysis of a stochastic recovery-relapse epidemic model with periodic parameters and media coverage

This paper addresses, motivated by mathematical work on infectious disease models, the impacts of environmental noise and media coverage on the dynamics of recovery-relapse infectious diseases. A susceptible-infectious-recovered-infectious model is formulated with both vertical transmission and horizontal transmission. The existence and uniqueness of the positive global solution is studied by constructing suitable Lyapunov-type function. Then, the existence of positive periodic solutions is verified by applying Khasminskii"s theory. The existence of positive periodic solutions indicates the continued survival of the diseases. Besides, sufficient conditions for the extinction of the diseases are obtained. Numerical simulations then demonstrate the dynamics of the solutions. The paper extends the results of the corresponding deterministic system.     

一类具有Hassell-Varley型功能反应和脉冲的扩散捕食系统的正周期解存在性

考虑了一类具有Hassell-Varley型功能反应和脉冲的扩散捕食系统,利用Mawhin延拓引理建立了这类系统周期解存在性的充分性条件.     

Positive periodic solutions of nonlinear differential systems with impulses

By using a fixed point theorem of strict-set-contraction, sufficient conditions for the existence of positive periodic solutions of nonlinear differential systems with impulses are obtained. As applications of our results, the existence of positive periodic solutions are established for delay Lotka–Volterra systems with impulses or without impulses.