常微分系统的脉冲镇定

本文考察了较一般形式的常微分系统的脉冲镇定问题,借助Lyapunov方法得到了该系统可脉冲指数镇定的充分判据,并给出了脉冲控制函数的具体算法．全文突出了脉冲在方程稳定性方面的控制效果,所得结果推广、改进了已有的相关结论．     

一类具有脉冲收获和投放的捕食系统的研究

建立了一类具有Ivlev功能反应函数的捕食系统,引入二次脉冲对该系统中捕食者进行作用,讨论了系统的有界性,利用Floquet理论和小振幅扰动方法,得出了食饵灭绝的周期解的局部稳定性和该系统最终持久生存的条件.     

脉冲微分方程的脉冲聚点存在的一般性条件

该文利用［５］,［６］中的比较性方法,在比文［７］中的条件更一般的情况下,证明了脉冲微分方程脉冲聚点的存在性,并给出了一个例子说明了该文的主要结果．     

泛函微分系统的脉冲控制

考察了较为一般形式的泛函微分系统x(t)=f(t,x(t),x(t—r))的脉冲控制问题.通过使用比较定理得到了系统在解存在唯一及f(t,x,y)连续的前提下,即可脉冲控制有界,吸引的结论;在弱利普希茨条件下,得到可脉冲控制稳定,渐近稳定及指数稳定的结论,并得到了脉冲控制的具体算法.     

一类非二次微分食饵—捕食系统的脉冲控制

利用脉冲微分方程的比较原理对一个具有功能反应函数为x~(1/2)的食饵—捕食生物模型进行研究.考虑到模型存在的不确定性,研究了捕食者的捕食率不但受食饵的密度大小影响,同时还受捕食者本身的密度影响的生物系统.通过脉冲控制得到了使其渐近稳定到原先不稳定的正平衡点的充分条件,使食饵密度和捕食者密度保持在一个定数附近并给出了生态解释.     

具脉冲效应的阶段结构单种群动力学模型

讨论了生物资源管理中的具脉冲出生与脉冲收获的单种群阶段结构动力学模型.利用离散动力系统频闪映射理论,得到了脉冲投放幼体对整个种群持续生存的重要意义.为现实的生物资源管理提供了可靠的策略依据,也丰富了脉冲微分方程理论.     

一类随机脉冲微分系统的稳定性

本文给出了随机脉冲微分系统零解的最终稳定性的定义,利用Liapunov函数,得到了非线性随机脉冲微分系统零解一致最终稳定性及一致最终渐进稳定性和最终不稳定的充分条件.     

增算子不动点定理及其对含间断项非线性脉冲方程的应用

设E是Banach空间,本文在比C[I,E]更一般的Banach空间中得到了几个新的非连续增算子不动点定理.作为应用,我们研究了Banach空间中含间断项的非线性脉冲积分方程和微分方程的最大解和最小解的存在性.     

具固定时刻的二阶脉冲微分系统零解的稳定性

利用脉冲微分不等式和分析技巧,构造Lyapunov函数给出了二阶具固定脉冲时刻的微分系统零解的稳定性的两个判定准则,特别突出了脉冲效应对系统稳定性的关键影响,并给出了其相关例子.     

具瞬时脉冲接种与非瞬时脉冲接种效应的一类新的SIR传染病模型研究

本文研究了瞬时脉冲接种与非瞬时脉冲接种效应的SIR传染病模型的问题.利用频闪映射和Floquet定理以及脉冲微分方程理论的方法,获得了模型无病周期解的存在性和疫苗接种的控制阈值的结果,推广了瞬时脉冲接种率与非瞬时脉冲接种区间长度对疾病灭绝起着重要作用的结论,为实际传染病控制提供了可靠的策略支持.     

关于运输问题最优解的进一步讨论

首先给出了运输问题最优解的相关概念,将最优解扩展到广义范畴,提出狭义多重最优解和广义多重最优解的概念及其区别.然后给出了惟一最优解、多重最优解、广义有限多重最优解、广义无限多重最优解的判定定理及其证明过程.最后推导出了狭义有限多重最优解个数下限和广义有限多重最优解个数上限的计算公式,并举例验证了结论的正确性.     

Seven common errors in finding exact solutions of nonlinear differential equations

We analyze the common errors of the recent papers in which the solitary wave solutions of nonlinear differential equations are presented. Seven common errors are formulated and classified. These errors are illustrated by using multiple examples of the common errors from the recent publications. We show that many popular methods in finding the exact solutions are equivalent each other. We demonstrate that some authors look for the solitary wave solutions of nonlinear ordinary differential equations and do not take into account the well - known general solutions of these equations. We illustrate several cases when authors present some functions for describing solutions but do not use arbitrary constants. As this fact takes place the redundant solutions of differential equations are found. A few examples of incorrect solutions by some authors are presented. Several other errors in finding the exact solutions of nonlinear differential equations are also discussed.     

Existence and qualitative features of entire solutions for delayed reaction diffusion system: the monostable case

The paper is concerned with the existence and qualitative features of entire solutions for delayed reaction diffusion monostable systems. Here the entire solutions mean solutions defined on the $ (x,t)\in\mathbb{R}^{N+1} $. We first establish the comparison principles, construct appropriate upper and lower solutions and some upper estimates for the systems with quasimonotone nonlinearities. Then, some new types of entire solutions are constructed by mixing any finite number of traveling wave fronts with different speeds $ c\geq c_* $ and propagation directions and a spatially independent solution, where $c_*>0$ is the critical wave speed. Furthermore, various qualitative properties of entire solutions are investigated. In particularly, the relationship between the entire solution, the traveling wave fronts and a spatially independent solution are considered, respectively. At last, for the nonquasimonotone nonlinearity case, some new types of entire solutions are also investigated by introducing two auxiliary quasimonotone controlled systems and establishing some comparison theorems for Cauchy problems of the three systems.     

一类广义四阶非线性Camassa-Holm方程的行波解

用动力系统的分支理论研究了一类广义四阶非线性Camassa-Holm方程的动力学行为和行波解,发现方程存在一些孤立波解,周期波解和一些诸如Compacton类型的非光滑行波解.在不同的参数条件下,给出了这些解存在的条件和一些特殊条件下的精确解.     

Inverse scattering transformation and soliton stability for a nonlinear Gross–Pitaevskii equation with external potentials

We consider the Gross–Pitaevskii(GP) equation with the combination of periodic and harmonic external potentials. In particular, the method of inverse scattering transformation is applied to the GP equation with external potentials. Furthermore, some exact soliton solutions are obtained for the GP equation by using inverse scattering transformation, in which some physically relevant bright solutions are described. The stabilities of the obtained matter-wave solutions are addressed numerically such that some stable solutions are found, and some solitons can be stable in a wide region. These results may raise the possibility of relative experiments and potential applications.     

A Method for Constructing Traveling Wave Solutions to Nonlinear Evolution Equations

In this paper, an analytical method is proposed to construct explicitly exact and approximate solutions for nonlinear evolution equations. By using this method, some new traveling wave solutions of the Kuramoto-Sivashinsky equation and the Benny equation are obtained explicitly. These solutions include solitary wave solutions, singular traveling wave solutions and periodical wave solutions. These results indicate that in some cases our analytical approach is an effective method to obtain traveling solitary wave solutions of various nonlinear evolution equations. It can also be applied to some related nonlinear dynamical systems.     

On NAVIER-STOKES and KELVIN-VOIGT Equations in Three Dimensions in Interpolation Spaces

We show for the three-dimensional initial-boundary value problem of the NAVIER -STOKES and KELVIN -VOIGT equation over bounded domains and for the corresponding stationary problem the existence of weak solutions in intermediate spaces between some of the usual spaces for weak solutions of the NAVIER -STOKES equations and spaces for the corresponding strong solutions. The proofs yield estimates of the solutions in terms of the data which are supposed to be in appropriate intermediate spaces. The basic ingredients of the proof are well-known results for weak and strong solutions and some nonlinear interpolation arguments.     

OSCILLATIONS OF A CLASS OF HIGH-ORDER LINEAR ODE WITH IMPULSES

Oscillation of solutions for a class of nth-order linear differential equation with impulses are considered and some sufficient conditions for oscillation of solutions are obtained, which improve and popularize some results in parts of the relative references.     

高阶泛函微分方程的振动性质*

本文借助于Lebesgue测度等工具研究了一类高阶非线性泛函微分方程的振动性质.文中指出.在一定条件下,方程的非振动解仅有两类,而且给出了每一类非振动解存在的必要条件,同时也建立了方程振动的若干充分判据.     

应用改进的简单方程法求非线性数学物理方程的精确解

应用改进的简单方程法求得Cahn-Allen方程和Jimbo-Miwa方程的精确解,这些解包括双曲函数解、三角函数解.当对双曲函数解中的参数取特殊值时,可以得到了孤立波解.当对三角函数解中的参数取特殊值时,可以得到对应的周期波函数解.实践证明,简单方程法对于研究非线性数学物理方程具有非常广泛的应用意义.