Global attractor for Hirota equation

The long time behavior of solution for Hirota equation with zero order dissipation is studied. The global weak attractor for this system in Hper^k is constructed. And then by exact analysis of the energy equation, it is shown that the global weak attractor is actually the global strong attractor in Hper^k.     

关于树的完美邻域集与无冗余集 (英)

本文首先给出了求树图T的完美邻域的多项式时间复杂度算法(A),并在此基础上证明了当S是T的任一完美邻域且｜S｜=θ(T),则S是T的一极大无冗余集．然后给出了由T的一极大无冗余集生成完美邻域集的多项式时间复杂度算法(B),并依此算法证明了若S为T的任一极大无冗余集,则T存在一独立完美邻域集U且｜U｜≤｜S｜．     

Conversion of longitudinal waves into electromagnetic radiation in a slowly varying plasma under W.K.B. approximation

This paper investigates the conversion of a dispersive longitudinal oscillation into reflected and transmitted electromagnetic radiation fields in slowly varying unmagnetized warm fluid plasmas, using W.K.B. approximations. The expressions for the power of the transmitted and reflected electromagnetic radiations, generated by electron acoustic waves, have also been obtained. It is shown that this conversion process becomes most efficient under certain conditions.

Nomenclature

In § 2 H magnetic field - H ₁ - u electron fluid velocity - k _t wave number of the transverse wave - k ₁ wave number of the longitudinal wave in electron fluid - m electronic mass - N ₀ number density of electrons in the unperturbed state - N perturbation in the electron number density - p perturbation in the electron fluid pressure - v _e adiabatic sound velocity of the electron fluid - K _t ² c ^{2 2}–e² - K ₁ ² v _e ^{2 2}–e² - wave frequency - _e electron plasma frequency - 1– _e ² / ² - c velocity of light in vacuum In § 3 K ₀ wave number in the 0X direction - K ₁ ² K ₁ ² –K ₀ ² - K ₂ ² K _t ² –K ₀ ² - K ₃ K ₁–K ₂ - K ₄ K ₁+K ₂ - K ₅ (K ₁ K ₂)^1/2 See Appendix A - A ₁ pressure amplitude of the reflected part of the incident wave - B ₁ pressure amplitude of the transmitted part of the incident wave - L characteristic length of variation ofN ₀ - e _x unit vector along 0X - e _z unit vector along 0Z In § 4 S _t Poynting flux of the transverse electromagnetic radiation - S _tZ ^/t Average of the transmitted part of the poynting flux along 0Z over the time period 2/ - S _tZ ^/r Average of the reflected part of the poynting flux along 0Z over the time period 2/ In § 5 S ₁ Energy flux carried by the longitudinal pressure wave - S _1Z ^/t Average of the transmitted part ofS ₁ along 0Z over the time period 2/     

Drop deformation under surfactants adsorption

The movements of free liquid drops, resulting from unbalanced surface tension gradients, in our case the adsorption of a surfactant, constitute important surface phenomena (Marangoni effect). The aim of this paper is to correlate the effect of pressure forces on the drop, with the surface coverage degree, namely with the extent to which the drop surface is covered by the surfactant. Our model shows that for a covered degree less then about 68°, these forces are negative. This means that these forces exerted by the external liquid upon the drop are oriented towards the negative direction of the normal to the drop surface, acting like a hammer. Some numerical data are given. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

加权Dirichlet 空间上的一般Ces$\grave{a}$ro算子

对加权Dirichlet空间${\cal D}_{\alpha}=\left\{f\in H(D) ; ||f||_{{\cal D}_{\alpha}}^{2}=|f(0)|^{2}+\int_{D}|f'(z)|^{2}(1-|z|)^{\alpha}\d m(z)<+\infty \right\},~~-1<\alpha<+\infty,$我们研究了其上一般Ces$\grave{a}$ro算子的有界性. 此处$H(D)$表示复平面单位圆盘$D$上全纯函数的全体.     

n-维赋范空间单位球极小球覆盖数2n-1与包含等距同构于（R^n-1，‖‖∞）的子空间

证明了对于一个n-维赋范空间X，如果b#=2n-1，则它一定包含一个与（R^n-1，‖‖∞）等距同构的子空间．     

含最大值项二阶中立型差分方程的渐近性

考虑含最大值项二阶中立型差分方程其中{an},{pn}和{qn}为实数列,k和■为整数且k≥1,■≥0,我们研究了方程(*)非振动解的渐近性．通过例子说明了含最大值项的方程和相应的不含最大值项方程之间的区别．     

Regular LDPC Codes from Semipartial Geometries

By considering a class of combinatorial structures, known as semipartial geometries, we define a class of low-density parity-check (LDPC) codes. We derive bounds on minimum distance, rank and girth for the codes from semipartial geometries, and present constructions and performance results for the classes of semipartial geometries which have not previously been proposed for use with iterative decoding.     

高阶单步A-稳定指数拟合法

In this paper,the necessary and sutlicient conditions for general one-step methoos to be exponentially fitted at q0∈C are given, A class of multtderivative hybrid one-step methods of order at least s 1 is constructed with s 1 parameters,where s is the order of derivative. The necessary and sufficient conditions for these methods to be A-stable and exponentially fitted is proved, Furthermore,a class of A-stable 2 parameters hybrid one-step methods of order at least 8 are constructed,which use 4th order derivative,These methods are exponentially fitted at q0 if and only its fitted function f(q) satisfies f(q0)= 0, Finally,an A-stable exponentlally fitted method of order 8 is obtained.     

p-Laplace非线性两点边值问题多个正解的存在性

本文利用一种新的三个泛函不动点定理得到了p-Laplacian方程在具有非线性边值条件时至少存在三个正解的充分条件,并且举了一个简单例子来说明得到的结论．