一类非线性拋物变分不等式解的存在性

本文研究了一类基于非线性抛物算子的变分不等式问题.首先,通过拓展偏微分方程的弱解理论定义了变分不等式的弱解.其次,利用惩罚函数并结合连续方法,证明了变分不等式存在弱解.     

Boussinesq方程解的部分正则性

本文考虑Boussinesq方程一类合适弱解的部分正则性.我们先运用广义能量不等式和奇异积分理论得到一些无维量的估计;再通过合适弱解满足的等式,运用迭代技巧,推导出温度场的小性估计;最后由尺度分析(scaling arguments)得到了一类合适弱解的部分正则性.     

一类非线性发展方程整体解的存在性、渐近性与解的爆破

研究一类非线性发展方程初边值问题整体弱解的存在性，渐近性和解的爆破问题，证明在关于非线性项的不同条件下，上述初边值问题分别在大初值和小初始能量的情况下存在整体弱解，并且讨论了弱解的渐近性。还证明：在相反的条件下，上述弱解在有限时刻爆破，并且给出了一个实例。     

三维Keller-Segel-Navier-Stokes方程弱解的整体存在性

本文证明具有logistic源的一个3维Keller-Segel-Navier-Stokes方程弱解的整体存在性,并研究了弱解的长时间行为.     

凸区域上椭圆方程弱解的边界唯一延拓性和B_p权特性

本文研究非光滑凸区域上的散度型二阶椭圆方程 ｉ（ａｉｊ（Ｘ）　ｊｕ（Ｘ））＝０的非零弱解的近边无穷次消失性和双倍性质，刻划弱解梯度在区域边界上的Ｂｐ权特性，建立弱解和弱解的梯度在凸区域边界的任意开子集上不可能同时消失的边界唯一延拓性定理．     

二阶正定型偏微分方程非齐次定解问题的能量方法

本文给出解决二阶正定型偏微分方程非齐次定解问题适定性的Hilbert空间框架,由于直接证明这类方程非齐次定解问题的弱解的存在性遇到困难,本文提出P_-拟弱解的概念,先证明P_-拟弱解的存在性,然后在适当的定解条件下证明P_-拟弱解就是P_-弱解,再证明Sarason弱强解的一致性,在典型定解问题的适定性的基础上进而可得一类定解问题Lu=f,的适定性,这里A可以是非局部的和非线性的,本文以多元混合型的Busemann方程为例将此框架具体化。     

一类三阶梯度流方程弱解的稳定性[英文]

本文研究R~3上的一类三阶梯度流方程弱解的稳定性问题.我们分别证明弱解的一个全局稳定性结果和一个渐近稳定性结果.所得结果改进了已有文献中的一些关于三阶梯度流方程弱解的稳定性结果.     

二阶正定型偏微分方程非齐次定解问题的能量方法

本文给出解决二阶正定型偏微分方程非齐次定解问题适定性的 Hilbert 空间框架.由于直接证明这类方程非齐次定解问题的弱解的存在性遇到困难,本文提出 P_-拟弱解的概念,先证明 P_-拟弱解的存在性,然后在适当的定解条件下证明 P_-拟弱解就是 P_-弱解,再证明Sarason 弱强解的一致性.在典型定解问题的适定性的基础上进而可得一类定解问题 Lu=f,的适定性.这里 A 可以是非局部的和非线性的.本文以多元混合型的 Basemana方程为例将此框架具体化.     

带雪崩项的半导体方程的瞬态解

研究带雪崩项的半导体方程的混合初边值问题．采用逼近过程和先验估计,在一定条件下,证明了该问题整体弱解的存在性或局部弱解的存在性．     

趋化NS系统弱解的全局存在性（英文）

本文主要研究趋化NS系统在2维的有界光滑领域Ω?R~2中.本文利用Galerkin方法证明了不可压缩的NS系统弱解的存在性.其次,利用一系列检验程序,证明了带有初边值条件的趋化NS系统弱解的局部存在性,进一步得到该系统弱解的全局存在性.     

RECENT PROGRESS ON SPHERICAL HARMONIC APPROXIMATION MADE BY BNU RESEARCH GROUP ——In memory of Professor Sun Yongsheng

As early as in 1990, Professor Sun Yongsheng, suggested his students at Beijing Normal University to consider research problems on the unit sphere. Under his guidance and encouragement his students started the research on spherical harmonic analysis and approximation. In this paper, we incompletely introduce the main achievements in this area obtained by our group and relative researchers during recent 5 years （2001-2005）. The main topics are： convergence of Cesaro summability, a.e. and strong summability of Fourier-Laplace series; smoothness and K-functionals; Kolmogorov and linear widths.     

Instructions for Authors

<正>Submission Authors must use LaTeX for typewriting,and visit our website www.actamath.com to submit your paper.Our address is Editorial Office of Acta Mathematica Sinica,Academy of Mathematics and Systems Science,Chinese Academy of Sciences,Beijing 100190,P.R.China.     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

正August 10-14,2015Beijin,China The International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Boundedness for commutators of multipliers on Hardy type spaces

In this paper, we study the commutators generalized by multipliers and a BMO function. Under some assumptions, we establish its boundedness properties from certain atomic Hardy space Hb^p（R^n） into the Lebesgue space L^p with p 〈 1.     

A unified approach to certain problems of best local approximation

In this paper we study best local quasi-rational approximation and best local approximation from finite dimensional subspaces of vectorial functions of several variables. Our approach extends and unifies several problems concerning best local multi-point approximation in different norms.     

Towards Excellence in Science Chinese Academy of Sciences

<正>May 26,2014,Beijing Science is a human enterprise in the pursuit of knowledge.The scientific revolution that occurred in the 17th Century initiated the advances of modern science.The scientific knowledge system created by     

THE 8~(th) INTERNATIONAL CONGRESS ON INDUSTRIAL AND APPLIED MATHEMATICS

<正>August 10-14,2015Beijing,ChinaThe International Congress on Industrial and Applied Mathematics(ICIAM)is the premier international congress in the field of applied mathematics held every four years under the auspices of the International Council for Industrial and Applied Mathematics.From August 10 to 14,2015,mathematicians,scientists     

Bounds for the zeros of polynomials

Let P(z)=∑↓j=0↑n ajx^j be a polynomial of degree n. In this paper we prove a more general result which interalia improves upon the bounds of a class of polynomials. We also prove a result which includes some extensions and generalizations of Enestrǒm-Kakeya theorem.