一类带有扩散与时滞的流行性传染病模型的行波解

讨论了一类带有扩散与时滞的流行性传染病模型的行波解的存在性.首先,将系统的行波解的存在性问题转化为一个二阶常微分方程组的单调解的存在性问题;应用单调方法和不动点方法,进一步地将问题转化为方程组的上下解的构造问题;应用所建立的引理与定理,通过构造适合的上下解,证明了系统单调行波解的存在性.     

带有非局部扩散项的霍乱传染病模型行波解的存在性

本文主要研究带有非局部扩散项的霍乱传染病模型行波解的存在性问题.首先当R0＞1,c＞c*时,利用Schauder不动点定理,构造了一对上下解,从而得到行波解的存在性.其次巧妙的构造Lyapunov函数结合Lebesgue控制收敛定理,得到行波解在+∞处的渐近行为.最后再研究当Ro＞1,c=c*时模型行波解的存在性.     

一类具有时滞和空间扩散的SIR传染病模型的行波解

研究了一类具有时滞和空间扩散的SIR传染病模型,通过分析相应的特征方程,讨论了系统每个平衡态的局部稳定性,通过运用交叉迭代方法和Schauder不动点定理,把行波解的存在性转化为一对上下解的存在性,通过构造一对上下解,得到了连接无病平衡态和地方病平衡态的行波解的存在性.     

一类具有非线性发生率与时滞的非局部扩散SIR模型的临界波的存在性

研究了一类具有时滞的非局部扩散SIR传染病模型的行波解。首先, 利用反证法证明了I是有界的, 并根据I的有界性研究了波速c>c*时行波解(波速大于最小波速的行波)的存在性。其次，利用c>c*的行波的存在性结果证明了临界波(波速等于最小波速的行波)的存在性。最后, 讨论了R0对临界波存在性的影响.     

带有扩散项和接种的传染病模型的行波解

该文研究带有扩散项和接种的传染病模型的行波解存在性.首先建立一个带扩散项和接种的具有空间结构的传染病模型,并给出其解适定性.其次,构造一对向量型上、下解,应用Schauder不动点原理和Lyapunov函数方法得到此模型存在连接无病平衡点和有病平衡点的非平凡正行波解.利用稳定流形定理,得到行波指数衰减估计,进而,通过拉普拉斯变换,确定该模型行波解的不存在性.该文的研究技巧对建立高维非合作反应扩散系统行波解存在性提供了有效方法.     

带非局部扩散项的一般性霍乱模型的行波解

该文研究一类具有一般性的带非局部扩散项的霍乱模型,用不同的函数表示人与人之间以及人与环境之间的发生率,以及霍乱病菌的增长函数.当R₀>1,c>c^*时,通过构造上下解函数,结合Schauder不动点定理讨论该模型行波解的存在性,再构造Lyapunov函数讨论行波解的渐近性.当c*时,通过双边拉普拉斯变换和Fatou引理证明该模型行波解的不存在性.     

移动环境下带有非局部扩散项和时滞的反应扩散方程的强迫行波解北大核心CSCD

该文考虑了移动环境下带有非局部扩散项和时滞的反应扩散方程的强迫行波解的存在性和唯一性.首先利用上下解方法和单调迭代原理得到强迫行波解的存在性,其中,该强迫行波解以环境移动的速度来变化.其次,该文结合最大值原理,利用挤压方法得到了该强迫行波解的唯一性.最后,作为该文得到的结论的应用,该文给出了两个经典的模型,一个是带非局部扩散项和时滞的Logistic模型,另一个是带有非局部扩散项和时滞的quasi-Nicholson’s Blowfiles人口模型.     

一类具有非线性发生率与时滞的离散扩散SIR模型临界行波解的存在性

研究了一类具有非线性发生率的离散扩散时滞SIR模型的临界行波解的存在性.在人口总数非恒定的条件下,首先,应用上下解法与Schauder不动点定理证明了解在有限闭区间上的存在性;其次,通过极限讨论了临界行波解在整个实数域上存在;最后,通过反证法与波动引理得到了行波解在无穷远处的渐近行为.     

带有外部输入项的时间周期SIR传染病模型的周期行波解北大核心CSCD

研究了一类带有外部输入项的时间周期SIR传染病模型周期行波解的存在性和不存在性.首先,通过构造辅助系统适当的上下解并定义闭凸锥,将周期行波解的存在性转化为定义在这个闭凸锥上的非单调算子的不动点问题,利用Schauder不动点定理建立辅助系统周期解的存在性,并利用Arzela-Ascoli定理证明了原模型周期行波解的存在性.其次,借助分析技术得到了周期行波解的不存在性.     

带有非局部扩散的反应流动扩散方程的行波解

本文主要考虑带有非局部扩散项的反应流动扩散方程行波解的存在性问题.首先,利用Schauder不动点定理和上下解原理得到带有非局部扩散项的反应流动扩散方程行波解的存在性,再将所得的结论应用到带有流动项的Lotka-Volterra竞争模型上,最后,考虑了流动项对繁殖速度的影响.同时,本文得到的存在性结论可以应用到一般的反应流动扩散方程中.     

Travelling waves in an infectious disease model with a fixed latent period and a spatio–temporal delay

This paper is concerned with the existence of travelling waves to an infectious disease model with a fixed latent period and a spatio–temporal delay. By analyzing the corresponding characteristic equations, the local stability of a disease-free steady state and an endemic steady state to this model is discussed. By constructing a pair of upper–lower solutions, we use the cross iteration method and the Schauder’s fixed point theorem to prove the existence of a travelling wave solution connecting the disease-free steady state and the endemic steady state. Numerical simulations are carried out to illustrate the main results.     

Travelling waves of a delayed SIRS epidemic model with spatial diffusion

This paper is concerned with the existence of travelling waves to an SIRS epidemic model with bilinear incidence rate, spatial diffusion and time delay. By analysing the corresponding characteristic equations, the local stability of a disease-free steady state and an endemic steady state to this system under homogeneous Neumann boundary conditions is discussed. By using the cross iteration method and the Schauder’s fixed point theorem, we reduce the existence of travelling waves to the existence of a pair of upper-lower solutions. By constructing a pair of upper-lower solutions, we derive the existence of a travelling wave solution connecting the disease-free steady state and the endemic steady state. Numerical simulations are carried out to illustrate the main results.     

Travelling waves of a three-species Lotka–Volterra food-chain model with spatial diffusion and time delays

This paper is concerned with the existence of travelling wave solutions to a three-species Lotka–Volterra food-chain model with spatial diffusion and time delays. By using the cross iteration method and Schauder’s fixed point theorem, we reduce the existence of travelling wave solutions to the existence of a pair of upper–lower solutions which are easy to construct in practice. Numerical simulations are carried out to illustrate the main results.     

Coinvasion–coexistence travelling wave solutions of an integro-difference competition system

This paper is concerned with the travelling wave solutions of an integro-difference competition system, of which the purpose is to model the coinvasion–coexistence process of two competitors with age structure. The existence of non-trivial travelling wave solutions is obtained by constructing generalized upper and lower solutions. The asymptotic and non-existence of travelling wave solutions are proved by combining the theory of asymptotic spreading with the idea of contracting rectangle.     

Bistable travelling waves in competitive recursion systems

This paper is devoted to the study of spatial dynamics for a class of discrete-time recursion systems, which describes the spatial propagation of two competitive invaders. The existence and global stability of bistable travelling waves are established for such systems under appropriate conditions. The methods involve the upper and lower solutions, spreading speeds of monostable systems, and the monotone semiflows approach.     

New type of travelling wave solutions

We study the existence of combustion waves for an autocatalytic reaction in the non‐adiabatic case. Based on the fact that the reaction system has canard solutions separating the slow combustion regime from the explosive one, we prove by applying the geometric theory of singularly perturbed differential equations the existence of a new type of travelling waves solutions, the so‐called canard travelling waves. Copyright © 2003 John Wiley & Sons, Ltd.     

一类退化-奇异抛物型方程的行波解Ⅱ

多孔介质动力学及生物群体动力学方程引起愈来愈多的人的注意,退化-奇异抛物型方程(u~m/m)_t=(u~k)_(xx)+u~nf(u)的行波解也成为人们关心的课题之一.Aronson对 m=k=1,u~nf(u)∈C~1[0,1]讨论了单调行波解的存在性与正则性,Hosono 对m=1,k≥2,n=0,f∈C~2[0,1],f(0)=f(1)=0,f′(0)<0,f″(0)(?)0,f′(1)<0且在(0,α)内 f(u)<0;在(α,1)内 f(u)>0,讨论了单调行波解的存在性与稳定     

Travelling waves for a size and space structured model in population dynamics: Point to sustained oscillating solution connections

This work is devoted to the study of travelling wave solutions for some size structured model in population dynamics. The population under consideration is also spatially structured and has a nonlocal spatial reproduction. This phenomenon may model the invasion of plants within some empty landscape. Since the corresponding unspatially structured size structured models may induce oscillating dynamics due to Hopf bifurcations, the aim of this work is to prove the existence of point to sustained oscillating solution travelling waves for the spatially structured problem. From a biological view point, such solutions represent the spatial invasion of some species with spatio-temporal patterns at the place where the population is established.     

Travelling Waves for Reaction Diffusion Equations

In this paper the travelling waves for the reaction diffusion equation in most general case is considered. The existence of travelling wave solutions is proved under very weak conditions, which are also necessary for the nonlinear term. A difference method is suggested and Leray-Scbauder fixed point theorem is used to prove the existence of discrete travelling waves. Then the convergence is shown and so the solution for the differential equation is obtained.