非线性强迫扰动Klein-Gordon方程的孤波渐近解法

研究了一类非线性强迫扰动Klein-Gordon方程.首先利用双曲正切待定系数法求得了典型的方程孤波解.然后利用泛函变分迭代原理得到了强迫扰动Klein-Gordon方程的一个近似解,并论述了解的一致有效性.所得到的近似解是一个解析式,它还可对近似解进行解析运算,而使用简单的模拟方法所得到的近似解是达不到这种效果的.     

广义高维Klein-Gordon强迫扰动方程的孤子解

利用同伦映射方法研究了一类非线性广义强迫扰动Klein-Gordon方程.首先利用双曲正切待定系数法求得了无扰动项典型方程的孤子解.然后利用同伦映射原理得到了强迫扰动Klein-Gordon方程的任意次近似孤子解.最后叙述了得到的近似孤子解是一个解析展开式,还能对它进行解析运算.这对使用简单的模拟方法得到的近似解是达不到的.     

二维空间中半线性摄动波动方程初值问题解的渐近理论

研究二维空间中具初值问题的半线性波动方程解的渐近理论,在二次连续的古典空间中得到了形式近似解的渐近合理性在长时间范围内成立,这一结果描述了渐近解的长时间存在性.作为所得到的渐近理论的应用,对二维空间中的一个特殊波动方程作出了分析.     

一类大气尘埃等离子体扩散模型研究

研究了一类大气非线性尘埃等离子体扩散方程初值问题.首先在无扰动情形下,利用Fourier变换方法得到了尘埃等离子体扩散方程初值问题的精确解,接着引入一个同伦映射,并选取初始近似函数,再用同伦映射理论,依次求出了非线性尘埃等离子体扰动初值问题的各次近似解析解.并引用不动点理论,指出了近似解析解的有效性和各次近似解的近似度,通过举例, 用模拟曲线和表格作了近似对照.最后,简述了用同伦映射方法得到的近似解的物理意义.简叙了用上述方法得到的各次近似解具有便于求解、精度高等优点.     

一个广义非线性扰动Klein-Gordon方程孤子解

研究了一个广义非线性扰动Klein-Gordon方程.利用同伦映射方法,首先构造了相应的同伦映射;然后选取了适当的初始近似;并计算各阶相应孤子近似解.同时还考虑了一个微扰方程.     

一类非线性无线电信号方程初值问题的解的渐近理论及应用(英)

本文建立了一类非线性无线电信号方程解的渐近理论．对时间变量t满足0≤t≤0（｜ε｜-1）（ε→0）时，在一个Sobolev空间中得到了初值问题的适定性及形式近似解的合理性．作为渐近理论的应用，在古典及Sobolev意义下，对一类特殊的电报方程作了讨论．     

一类非线性无线电信号方程初值问题的解的渐近理论及应用

本文建立了一类非线性无线电信号方程解的渐近理论，对时间变量ｔ满足０≤ｔ≤０（│ε│＾－１（ε→０）时，在一个Ｓｏｂｏｌｅｖ空间中得到初值问题的适定性及形式近似解的合理性，作为渐近理论的应用，在古典及Ｓｏｂｏｌｅｖ意义下，对一害特殊的电报方程作了讨论。     

半线性摄动电报方程的渐近理论及应用

对二阶半线性摄动电报方程的初值问题.本交给出了一个渐近方法.证明了渐近理论及形式近似解的合理性都在时间变量无穷大时(即0≤t≤O(|ε|-1)成立.作为浙近理论的应用,我们对一个带初问题的特殊电报方程进行了研究,得到了两个|ε|-1阶渐近近似解.     

一类非线性强阻尼扰动发展方程的解

研究了在数学、力学中广泛出现的一类三阶非线性强阻尼发展扰动偏微分方程,并求其近似解析解.首先,构造一个泛函同伦映射,将方程的解表示以人工参数的幂级数形式,代入同伦映射,得到一个非线性扰动方程解的逐次迭代关系式,并考虑对应的一个无扰动项情形下的强阻尼发展方程,利用Fourier变换理论,求出其精确解.其次,以得到的精确解为同伦映射迭代式的初始函数,通过非线性扰动方程解的迭代关系式,再用Fourier变换法求解对应的方程.最后,便依次地得到了非线性强阻尼发展扰动偏微分方程的各次近似解析解.用上述方法得到的各次近似解,具有便于求解、精度高等特点.     

一类非线性双曲型发展方程的孤子解

研究了一类非线性发展方程.首先在无扰动情形下,利用待定函数和泛函同伦映射方法得到了非扰动发展方程的孤子精确解和扰动方程的任意次近似行波孤子解.接着引入一个同伦映射,并选取初始近似函数,再用同伦映射理论,依次求出非线性双曲型发展扰动方程孤子解的各次近似解析解.再利用摄动理论举例说明了用该方法得到的近似解析解的有效性和各次近似解的近似度.最后,简述了用同伦映射方法得到的近似解的意义,指出了用上述方法得到的各次近似解具有便于求解、精度高等优点.     

Mixed initial–boundary value problem for the Benjamin–Ono equation

We consider the mixed initial–boundary value problem for the Benjamin–Ono equation on a half-line. We study traditionally important problems of the theory of nonlinear partial differential equations, such as global in time existence of solutions to the initial–boundary value problem and the asymptotic behavior of solutions for large time.     

Neumann initial–boundary value problem for Benjamin–Ono equation

We consider the Neumann initial–boundary value problem for Benjamin–Ono equation on a half-line. We study traditionally important problems of the theory of nonlinear partial differential equations, such as global in time existence of solutions to the initial–boundary value problem and the asymptotic behavior of solutions for large time.     

双参数非线性非局部奇摄动抛物型初始-边值问题的广义解

研究了一类广义抛物型方程奇摄动问题.首先在一定的条件下, 提出了一类具有两参数的非线性非局部广义抛物型方程初始 边值问题.其次证明了相应问题解的存在性.然后, 通过Fredholm积分方程得到了初始 边值问题的外部解.再利用泛函分析理论和伸长变量及多重尺度法, 分别构造了初始 边值问题广义解的边界层、初始层项,从而得到了问题的形式渐近展开式.最后利用不动点理论证明了对应的非线性非局部广义抛物型方程的奇异摄动初始 边值问题的广义解的渐近展开式的一致有效性.     

Asymptotic behavior of solutions to a class of nonlinear wave equations of sixth order with damping

We investigate the initial value problem for a class of nonlinear wave equations of sixth order with damping. The decay structure of this equation is of the regularity‐loss type, which causes difficulty in high‐frequency region. By using the Fourier splitting frequency technique and energy method in Fourier space, we establish asymptotic profiles of solutions to the linear equation that is given by the convolution of the fundamental solutions of heat and free wave equation. Moreover, the asymptotic profile of solutions shows the decay estimate of solutions to the corresponding linear equation obtained in this paper that is optimal under some conditions. Finally, global existence and optimal decay estimate of solutions to this equation are also established. Copyright © 2016 John Wiley & Sons, Ltd.     

Validity of the Weakly Nonlinear Solution of the Cauchy Problem for the Boussinesq‐Type Equation

We consider the initial‐value problem for the regularized Boussinesq‐type equation in the class of periodic functions. Validity of the weakly nonlinear solution, given in terms of two counterpropagating waves satisfying the uncoupled Ostrovsky equations, is examined. We prove analytically and illustrate numerically that the improved accuracy of the solution can be achieved at the timescales of the Ostrovsky equation if solutions of the linearized Ostrovsky equations are incorporated into the asymptotic solution. Compared to the previous literature, we show that the approximation error can be controlled in the energy space of periodic functions and the nonzero mean values of the periodic functions can be naturally incorporated in the justification analysis.     

具有边界摄动的非线性非局部反应扩散方程的奇摄动问题

A class of nonlinear nonlocal singularly perturbed Robin initial boundary value problems for reaction diffusion equations with boundary perturbation is considered. Under suitable conditions, firstly, the outer solution of the original problem is obtained; secondly, by using the stretched variable, the composing expansion method and the expanding theory of power series, the initial layer is constructed; and finally, by using the theory of differential inequalities the asymptotic behavior of solutions for initial boundary value problems is studied, and including some relational inequalities the existence and uniqueness of solutions for the original problem and the uniformly valid asymptotic estimation are discussed.     

奇摄动分数阶微分方程的渐近解

本文研究了一类奇摄动非线性分数阶微分方程初值问题.利用伸长变量构造出解的形式展开式,并利用微分不等式理论,证明了解的一致有效的渐近式.所得的结果具有较好精度的近似解.     

一类具非线性边界条件的高阶方程的双参数奇摄动问题

研究了一类含双参数的非线性高阶微分方程的奇摄动问题.运用合成展开法构造了问题的形式渐近解,并运用微分不等式理论证明了原问题解的存在性及所得形式渐近解的一致有效性.     

Regular and Irregular Solutions in the Problem of Dislocations in Solids

For an initial differential equation with deviations of the spatial variable, we consider asymptotic solutions with respect to the residual. All solutions are naturally divided into classes depending regularly and irregularly on the problem parameters. In different regions in a small neighborhood of the zero equilibrium state of the phase space, we construct special nonlinear distribution equations and systems of equations depending on continuous families of certain parameters. In particular, we show that solutions of the initial spatially one-dimensional equation can be described using solutions of special equations and systems of Schr¨odinger-type equations in a spatially two-dimensional argument range.