仅有y-分量耦合的非恒同Lorenz系统的渐近同步

本文考虑外部耦合格式为n×n阶实对称不可约,行和为零且对角线以外的元素非正的矩阵,内部耦合格式为仅有y-分量参与耦合的非恒同Lorenz格点系统的渐近同步.在系统解一致有界耗散的基础上采用常数变易法证明了当耦合强度足够大时仅有y-分量参与耦合的非恒同Lorenz格点系统的解出现渐近同步,即系统解的任意两个对应分量的差在时间趋向于无穷时是一个小的有界量.     

仅有x-分量耦合的非恒同Lorenz系统的渐近同步

考虑外部耦合格式为n×x阶实对称不可约,行和为零且对角线以外的元素非正的矩阵,内部耦合格式为仅有x-分量参与耦合的非恒同Lorenz格点系统的渐近同步.运用Lyapunov稳定性理论讨论系统解的一致有界耗散性.并在此基础上采用Cauchy-Schwaxz不等式证明当耦合强度足够大时仅有x-分量参与耦合的非恒同Lorenz格点系统的解出现渐近同步,即系统解的任意两个对应分量的差在时间趋向于无穷时是一个小的有界量.     

Neumann边界条件下离散化强阻尼Sine-Gordon方程的全局吸引性

本文主要研究Neumann边界条件下带有周期外力的离散化强阻尼Sine-Gordon方程的全局吸引性.当摩擦系数足够大时,该系统将拥有一族周期解,这些周期解彼此之间只相差-个常向量的整数倍,并且该系统的任意一个解都将被其中的-个周期解所吸引.     

非自治Ginzburg-Landau方程的周期解和全局周期吸引子

研究受周期外力影响的非自治Ginzburg-Landau方程的解的长时间行为.首先证明系统在空间H上存在周期解,而且周期解包含在空间V中的一个有界吸收集内.然后证明了当耗散系数λ满足一定条件时,该系统在空间H上具有唯一的周期解,该周期解指数吸引H中的任意有界集.     

关于具间接阻尼的强耦合波动方程组的边界耗散传输的敏感性

本文考察由两个强耦合的波动方程组成的间接边界阻尼反馈系统的稳定性,阐明此类系统的稳定性依赖于耦合的类型、无阻尼系统是否有隐含正则性、以及边界耗散的阶数和无阻尼边界条件间的匹配等诸多因素.首先证明,当无阻尼边界为Dirichlet边界条件时,系统是一致指数稳定的;而当其为Neumann边界条件时,只能建立系统的多项式稳定性.其次,通过谱分析的方法,揭示间接边界阻尼反馈系统的能量在方程间的传递与无阻尼边界条件之间的内在联系.     

具有粘弹性和热粘弹性方程组的全局周期吸引子

证明了具有粘弹性和热粘弹性方程组在Dirichlet边界条件下,对于任意的非自治时间周期受迫力,均具有唯一的指数吸引任何有界集的周期解,即全局周期吸引子.并且如果受迫力是自治的,则全局周期吸引子恰是系统唯一的指数吸引有界集的平衡解.     

Duffing型方程组的边界值问题的解的存在性

给出了带Dirichlet边界条件、Neumann边界条件和周期边界条件的Duffing型方程组的两点边界值问题的解的几个存在性定理。     

非自治Ginzburg-Landau方程的有限维行为

本文研究Ω(с)Rn(n=1,2,3)上具有几乎周期外力的非自治Ginzburg-Landau方程的有限维行为.证明了非自治Ginzburg-Landau系统存在紧的一致吸引子A1.当外力是时间拟周期时,得到了吸引子A1的Hausdorff维数的上界估计.当外力是时间周期时,证明了吸引子里一定含有周期解,而且当耗散系数λ满足适当条件时,系统在空间H=L2(Ω)上存在唯一周期解,该周期解指数吸引H中的任何有界集.     

非自治Ginzburg-Landau方程的有限维行为

本文研究Ω R~n(n=1,2,3)上具有几乎周期外力的非自治Ginzburg-Landau方程的有限维行为。证明了非自治Ginzburg-Landau系统存在紧的一致吸引子A_1。当外力是时间拟周期时,得到了吸引子A_1的Hausdorff维数的上界估计,当外力是时间周期时,证明了吸引子里一定含有周期解,而且当耗散系数λ满足适当条件时,系统在空间H=L~2(Q)上存在唯一周期解,该周期解指数吸引H中的任何有界集。     

具有非线性扩散项的多维趋化趋触模型的整体有界性

本文主要研究一类带有齐次Neumann边界条件且具有非线性扩散项的趋化趋触模型,在较宽的条件下,证明了系统具有整体有界古典解.推广了XU等(2019)和JIA等(2020)得到的整体有界的古典解的结论.     

Asymptotic synchronization in n-dimensional second order dissipative lattices of coupled oscillators

By introducing a new norm which is equivalent to the usual norm in the phase space, we prove that for n-dimensional second order dissipative lattices of coupled oscillators with external periodic forces under Dirichlet, Neumann and periodic boundary conditions, if the system is bounded dissipative and the coupled coefficients are both large enough, the asymptotic synchronization will occur. And we give a concrete bounded dissipative second order lattices system. Our results show that the bounds of the difference between the components of any solution are directly proportional to mn/2 and inversely proportional to the coupled coefficients, where m is the mesh size and n is the space dimension of lattice points.     

Periodic and Almost Periodic Solutions for a Coupled System of Two Korteweg-de Vries Equations with Boundary Forces

In this paper, we investigate a coupled system of two Korteweg-de Vries equations on a bounded domain. We discuss the long-time behavior of this system with forces on the left Dirichlet boundary conditions. We obtain that if the forces are periodic (almost periodic) with small amplitude, then the solution of the coupled system is periodic (almost periodic).     

Determination of generalized exact boundary synchronization matrix for a coupled system of wave equations

For a coupled system of wave equations with Dirichlet boundary controls, this paper deals with the possible choice of its generalized synchronization matrices so that the admissible generalized exact boundary synchronizations for this system are obtained.     

Coexistence and Asymptotic Periodicity in a Competition Model of Plankton Allelopathy

In this paper, the two species Lotka-Volterra competition model of plankton allelopathy from aquatic ecology is discussed. The authors study the existence of solutions to a strongly coupled elliptic system with homogeneous Dirichlet boundary conditions and consider the existence, stability and global attractivity of time-periodic solutions for a coupled parabolic equations in a bounded domain. Their results show that this model possesses at least one coexistence state if cross-diffusions and self-diffusions are weak. The existence of the positive T-periodic solutions and the global stability as well as the global attractivity for the parabolic system are also given.     

Phase-field systems with nonlinear coupling and dynamic boundary conditions

We consider phase-field systems of Caginalp type on a three-dimensional bounded domain. The order parameter fulfills a dynamic boundary condition, while the (relative) temperature is subject to a homogeneous boundary condition of Dirichlet, Neumann or Robin type. Moreover, the two equations are nonlinearly coupled through a quadratic growth function. Here we extend several results which have been proven by some of the authors for the linear coupling. More precisely, we demonstrate the existence and uniqueness of global solutions. Then we analyze the associated dynamical system and we establish the existence of global as well as exponential attractors. We also discuss the convergence of given solutions to a single equilibrium.     

On the resolvent arising in a parameter‐elliptic multi‐order boundary problem

In this paper we consider a boundary problem for a parameter‐elliptic, multi‐order system of differential equations defined over a bounded region in $\mathbb {R}^n$ and under limited smoothness assumptions as well as under boundary conditions which include those of Dirichlet. Information is then derived concerning the asymptotic behaviour of the trace of a power of the resolvent of the Hilbert space operator, in general non‐selfadjoint, induced by the boundary problem under null boundary conditions. This information will then be used in a subsequent work to derive various results pertaining to the asymptotic behaviour of the eigenvalues of this operator.     

From phenomena of synchronization to exact synchronization and approximate synchronization for hyperbolic systems

In this survey paper, the synchronization will be initially studied for infinite dimensional dynamical systems of partial differential equations instead of finite dimensional systems of ordinary differential equations,and will be connected with the control theory via boundary controls in a finite time interval. More precisely,various kinds of exact boundary synchronization and approximate boundary synchronization will be introduced and realized by means of fewer boundary controls for a coupled system of wave equations with Dirichlet boundary controls. Moreover, as necessary conditions for various kinds of approximate boundary synchronization, criteria of Kalman's type are obtained. Finally, some prospects will be given.     

On a grid-method solution of the Laplace equation in an infinite rectangular cylinder under periodic boundary conditions

We study the Dirichlet problem for the Laplace equation in an infinite rectangular cylinder. Under the assumption that the boundary values are continuous and bounded, we prove the existence and uniqueness of a solution to the Dirichlet problem in the class of bounded functions that are continuous on the closed infinite cylinder. Under an additional assumption that the boundary values are twice continuously differentiable on the faces of the infinite cylinder and are periodic in the direction of its edges, we establish that a periodic solution of the Dirichlet problem has continuous and bounded pure second-order derivatives on the closed infinite cylinder except its edges. We apply the grid method in order to find an approximate periodic solution of this Dirichlet problem. Under the same conditions providing a low smoothness of the exact solution, the convergence rate of the grid solution of the Dirichlet problem in the uniform metric is shown to be on the order of O(h ² ln h ⁻¹), where h is the step of a cubic grid.     

Exclusion of boundary blowup for 2D chemotaxis system provided with Dirichlet boundary condition for the Poisson part

We study a chemotaxis system on bounded domain in two dimensions where the formation of chemical potential is subject to the Dirichlet boundary condition. For such a system the solution is kept bounded near the boundary and hence the blowup set is composed of a finite number of interior points. If the initial total mass is 8π and the domain is close to a disc then the solution exhibits a collapse in infinite time of which movement is subject to a gradient flow associated with the Robin function.     

On the existence of solutions for a system of difference equations with non-monotone nonlinearity

We derive a dual variational method in order to obtain the existence of a bounded solution to a certain nonlinear system with non-monotone nonlinearities. We consider such a system representing a difference equation arising from evaluating some Dirichlet boundary value problems.