Periodic blow-up solutions and their limit forms for the generalized Camassa–Holm equation

In this paper, we consider the generalized Camassa–Holm equation u_t + 2kux - u_xxt + au²u_x=2u_xu_xx + uu_xxx. Under substitution ξ x = ct, some new explicit periodic wave solutions and their limit forms are presented through some special phase orbits. These periodic wave solutions tend to in?nity on ξ- u plane periodically. Thus we call them periodic blow-up solutions. To our knowledge, such periodic blow-up solutions have not been found in any other equations.     

Effective mass approach for a Bose-Einstein condensate in an optical lattice

We study the stationary and propagating solutions for a Bose-Einstein condensate （BEC） in a periodic optical potential with an additional confining optical or magnetic potential. Using an effective mass approximation we express the condensate wave function in terms of slowly-varying envelopes modulating the Bloch modes of the optical lattice. In the limit of a weak nonlinearity, we derive a nonlinear Schrodinger equation for propagation of the envelope function which does not contain the rapid oscillation of the lattice. We then consider the ground state solutions in detail in the regime of weak, moderate and strong nonlinear interactions. We describe the form of solution which is appropriate in each regime, and place careful limits on the validity of each type of solution. Finally we extend the study to the propagating dynamics of a spinor atomic BEC in an optical lattice and some interesting phenomena are revealed.     

Behavior of the solutions to an othmer-stevens chemotaxis model with reproduction term

In this paper,we study a simplified Othmer-Stevens model with reproduction term. By making use of a smart function transformation,the comparative method and some special mathe-matical analysis,we prove the existence of global,blow-up or quenching solutions of the problem on different conditions. More interesting results are reached. The result of the paper not only verifies a real biological phenomenon,but also provides a theo-retical groundwork for numerical problems of the chemotaxis model.     

THE EXISTENCE OF PERIODIC SOLUTIONS TO DISCRETE—TIME NONLINEAR STOCHASTIC SYSTEMS

In this paper, we have presented some general necessary and sufficient conditions for the existence of periodic solutions to nonlinear stochastic difference equations on semi-compact topological space. Effective sufficient conditions in terms of Lyapunov functions are derived for the systems linear in noise.     

The periodic solution for a kind odd order delay differential equation

In this paper, we use the coincidence degree theory to research the odd order delay differential equation a(t)χ(2n+1)(t)+b(t)χ(t)+g(t,-τ(t)))=p(t), and we obtain the sufficient conditions for the existence of periodic solutions, which improves and generalizes some related results in the literatures.     

Blow—up Estimtes for a Non—Newton Filtration Equation

The purpose of this paper is to derive an upper bound for the rate of blow-up of solutions to the Non-Newton filtration equation where u ≥ 0,p ＞ 1. The blow up rate estimates of positive radial solutions were established by Weissler in [I]for the (1)′ with p=2. In this paper,we get same result for the (1) or (1)′ with p＞1. Then,it extent and complment result in [1].     

Asymptotic behavior of solutions for the one-dimensional drift-diffusion model in the quarter plane

In this paper, we study the classical drift-diffusion model arising from the semiconductor device simulation, which is the simplest macroscopic model describing the dynamics of the electron and the hole. We prove the global existence of strong solutions for the initial boundary value problem in the quarter plane. In particular, we show that in large time, these solutions tend to the nonlinear diffusion wave which is different from the steady state, at an algebraic time-decay rate. As far as we know, this is the first result about the nonlinear diffusion wave phenomena of the solutions for the one-dimensional drift-diffusion model in the quarter plane.     

Existence of Young measure solutions of a class of singular diffusion equations

The first initial-boundary value problem of a class of singular diffusion equations with the flux sublinear growth and the potential without convexity is investigated. Such equations may be strongly degenerate, singular and forward-backward. Inspired by the idea in a recent work of Demoulini, we first discuss the regular case by introducing the Young measure solutions and prove the existence of such solutions. Consequently, we approximate the extreme case by the method of regularization. By means of some uniform estimates and some techniques, the existence of Young measure solutions with bounded variation is established.     

Long Time Behaviors of the Solutions to Stochastic Wave Equations with Damping

The long time behavior of the solution to a stochastic wave equation with damping is considered. Under some appropriate conditions, the exponential stability of the solutions holds almost surely.Finally two examples to illustrate the results are given.     

Formation and transport of granular heaps in vertically vibrated containers with periodic corrugated bottoms

We report the formation and transportation of granular heaps in vertically vibrated containers with two types of periodic corrugated bottoms： one with a periodic array of ten identical plexiglas rectangles mounted （named the periodic container）, and the other with a single-step （named the single-step container）. For the periodic container, when the excitation was weaker, several small＇heaps formed, and the number of them was the same as that of the rectangles on the bottom. As the excitation increased, the system presented three types of states： single well-defined heap, weaker wave, and stronger wave. Some local convections were observed in the interior of heap. For the single-step container, we observed the transportation of a heap toward step. We propose that the compressive force from the amblent gas plays a crucial role in the movement of the heap.     

(N+1)维广义的Boussinesq方程的精确显式非线性波解

研究(N+1)维广义的Boussinesq方程的非线性波解.利用动力系统定性理论和分支方法,获得它的多种非线性波解的精确显式表达式,这些解包括孤立波解,爆破解,周期爆破解和扭波型解.     

耦合的修正变系数KdV方程的非线性波解

研究一个带变系数的耦合修正KdV方程的非线性波解,利用F-展开法获得多种非线性波解,这些解包括孤立波解、扭波解(反扭波解)、爆破解和周期爆破解.带变系数的耦合修正KdV方程具有扭波解(反扭波解),而对于带变系数的耦合KdV方程,却未得到.这个结果与修正KdV方程和KdV方程的情形是类似的.     

一类广义五阶KdV方程新的精确解

本文运用辅助方程法,借助Mathematica软件,获得了一类广义五阶KdV方程的19个精确解,其中有17个是新得到的,这些解包括光滑孤立波解,爆破解,周期爆破解．     

带有边界阻尼项和源项的非线性波方程的解的爆破

文章利用能量法研究带有边界阻尼和源项的非线性波方程,并且得到正初始能量时非线性波方程的解爆破的充分条件．     

带有边界阻尼项和源项的非线性波方程

文章利用能量法研究带有边界阻尼和源项的非线性波方程,并且得到负初始能量时非线性波方程的解爆破的充分条件．     

映射法与Klein-Gordon方程新的精确解

运用映射法,结合辅助方程,利用计算机代数系统Mathematica求出了非线性Klein-Gordon方程的一系列新的精确周期解,补充了前面研究的结果.这些精确解可在极限情况下(m→1)退化为孤波解.该方法简化了求解过程,并可以用来求解其他的非线性演化方程,如Schrǒdinger方程、KP方程等.     

映射法与非线性波动方程新的精确解

本文运用映射法,结合辅助方程,利用计算机代数系统Mathematica求出了典型的非线性mKdV方程和Klein-Gordon方程的一系列新的精确周期解。该方法可以用来求解更多非线性方程。     

扩展映射法与Boussinesq方程新的精确解

运用扩展映射法,结合辅助方程,利用计算机代数系统Mathematica求出Boussinesq方程一系列新的精确周期解,这些精确解在极限情况下(m→1)退化为相应的孤波解.该方法也可用来求解其他非线性演化方程,如Klein-Gordon方程和Benjamin方程等.     

扩展的映射法与非线性色散K（n，k）方程的新紧致子和孤波

利用扩展的映射法,得到了非线性色散K（n,k）方程几类新的紧致子、孤波和周期波解。当n=k〉1,非线性色散K（n,k）方程存在紧致子解和周期波解;当n=k〈1,存在孤波解。本文所得到的K（n,k）方程的紧致子解和周期波解,涵盖了用其它方法得到的所有解,如文献[20-23]。我们的结果进一步丰富了对非线性色散现象的认识。     

(2+1)维KD方程的扰动非行波双孤子和周期解

应用退耦变换和Lie对称群方法,将(2+1)维KD方程的约化成了(1+1)维非线性PDE。通过广义同宿测试法获得了该方程新的扰动非行波双孤子解及其动力学临界点和参数极限情况下的非行波有理函数奇解。运用二维平面动力系统的Hamilton函数讨论了对称约化方程在波变换下的周期解存在性,并用正切函数拟设法得到了该周期解的显式精确表达,相应获得了KD方程的扰动非行波周期解析解。