Lienard型系统解的定性行为

该文讨论非线性系统狓＝１犪（狓）（犺（狔）－犉（狓）），　狔＝－犪（狓）犵（狓） （Ｅ）解的一些定性行为，获得了系统（Ｅ）为振动，全局渐近稳定，全局中心的充要条件和周期解的存在的充分条件．     

Glimm方法对于燃烧模型含爆燃波及爆轰波解的收敛性

该文对于反应速率无穷的燃烧模型组的初值问题证明了当初值狌０（狓）,狕０（狓）的变差有界时,对于含爆燃（ＤＦ）波及爆轰（ＤＴ）波解的Ｇｌｉｍｍ 格式的收敛性,其中犳′（狌）＞－Λ,犳′（０）＜０,犳″（狌）＞０,犳″（狌）≥δ＞０ （狌≥０）,常数狇＞０,以及当狌０ （狓）＞０时狕０（狓）＝０．     

相依样本下线性模型误差分布的相合估计

对于线性模型狔犻＝狓犻′β＋犲犻，犻＝１，…，狀，设误差序列｛犲犻｝是平稳的α 混合序列，犳（狓）为其 公共的未知密度函数，我们讨论了基于残差的犳（狓）的核估计＾犳狀（狓）＝１狀犪狀∑狀犻＝１犓（＾犲狀犻－狓犪狀）的弱相合性、逐点强相合性、一致强相合性及其收敛速度，其中＾犲狀犻为Ｌ．Ｓ．估计的残差．     

半线性抛物方程可变号解的全局存在和爆破

该文研究了如下柯西问题狌狋＝狌狓狓＋ （狋＋１）－σ／２狘狓狘σ狘狌狘狆－１狘狌狘，　狓∈犚，狋∈犚＋ ，狌（狓，０）＝狌０（狓），　狓∈犚｛ ．其中参数σ≥０，狌０（狓）在犚上犽次变号，满足某种速降条件．证明了：如果ｍａｘ｛σ，１｝＜狆≤１＋２犽＋１，那么所有非零解在有限时间内爆破；如果狆＞ｍａｘ｛σ，１＋２犽＋１｝则存在一个非零全局解．     

一簇Lorenz映射的混沌行为与统计稳定性

该文研究一簇Ｌｏｒｅｎｚ映射犛犪：［０,１］→［０,１］（０＜犪＜１）犛犪（狓）＝狓＋犪　狓∈ ［０,１－犪）｛（狓＋犪－１）／犪　狓∈ ［１－犪,１］．从拓扑的角度考虑了犛犪的混沌行为,证明了：犛犪有稠密轨道;犛犪的周期的集合犘犘（犛犪）＝｛１,犿＋１,犿＋２,…｝,其中犿为使犪犿＜１－犪成立的最小正整数;犛犪的拓扑熵犺（犛犪）＞０;几乎所有（关于Ｌｅｂｅｓｇｕｅ测度）的点狓的Ｌｙａｐｕｎｏｖ指数λ（犛犪,狓）＝λ犪＞０．从统计的角度讨论了犛犪的稳定性．我们用下界函数方法证明了犛犪是统计稳定的,并且狌犵犪（犃）＝∫犃犵犪（狓）ｄ狓（犃∈犅）为犛犪的唯一绝对连续（关于Ｌｅｂｅｓｇｕｅ测度）不变概率测度．同时,不变密度犵犪在参数扰动和随机作用的随机扰动下是稳定的．     

一个抛物型方程不适定问题的小波正则化方法

一维抛物型方程如下定解问题狌狋＋狌狓＝狌狓狓， ０≤狓＜ ∞，０≤狋＜ ∞，狌（１，狋）＝犵（狋）， ０≤狋＜ ∞，狌（狓，０）＝０， 狓≥０烅烄烆．是一个不适定问题．数据犵的微小变化可以引起解的巨大误差．该文通过构造一个在频域具紧支集的小波并在尺度空间上展开数据和解，滤除了高频分量，并结和Ｇａｌｅｒｋｉｎ方法，建立了一种逼近准确解的正则化方法，恢复了解对数据的连续依赖性，并建立了误差估计．     

高阶奇异积分的小波逼近及数值计算

该文所讨论的是在Ｈａｄａｍａｒｄ主值意义下，高阶奇异积分（犛犳）（狋）＝∫ 犳（狓）（狓－狋）狀＋１ｄ狓，　　狀≥１的小波逼近及数值计算．特别是当小波函数未知时，借助于方程（３．１），对高阶奇异积分作数值计算，建立了收敛性定理．     

中立型时滞微分方程的渐近稳定性

考虑具有正负系数的中立型时滞微分方程ｄｄ狋［狓（狋）－犘（狋）狓（狋－τ）］＋犙（狋）狓（狋－δ）－犚（狋）狓（狋－σ）＝０，　狋≥狋０， 其中Ｐ（ｔ）∈Ｃ（［ｔ０，∞），Ｒ），Ｑ（ｔ），Ｒ（ｔ）∈Ｃ（［ｔ０，∞），Ｒ＋ ），τ，δ，σ∈（０，∞）．获得了该方程零解 一致稳定及渐近稳定的充分条件，它推广并改进了现有文献中的结论．     

超扩散过程的遍历定理

考虑初始测度为Ｌｅｂｅｓｇｕｅ测度μ 的一致椭圆超扩散过程，其分枝特征为ψ（狓，狕）＝犫（狓）狕＋γ（狓）狕２．该文研究这类超过程的占位时过程的极限性质．对系数犫（狓）及γ（狓）做必要的限制，得到了占位时过程在空间维数犱≤２的遍历定理，我们的结果是［６］的补充．     

具有分布滞量的微分系统的周期解和全局吸引性

利用重合度理论中的延拓定理和Ｌｙａｐｕｎｏｖ泛函方法讨论一类具有分布滞量的微分系统狓（狋）＝ 犃（狋）狓（狋）＋∫０－狉犳（狋,狊,狓狋＋狊））ｄ狊的周期解的存在性和全局吸引性,得到了便于应用的新结果．     

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.     

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.     

Boundedness of commutators related to Marcinkiewicz integrals on hardy type spaces

In this paper, the authors study the boundedness of the operator [μΩ, b], the commutator generated by a function b ∈ Lipβ(Rn)(0 ＜β≤ 1) and the Marcinkiewicz integrals μΩ, on the classical Hardy spaces and the Herz-type Hardy spaces in the case Ω∈ Lipα(Sn-1)(0 ＜α≤ 1).     

Generalization of the interaction between Haar approximation and polynomial operators to higher order methods

In applications it is useful to compute the local average empirical statistics on u. A very simple relation exists when of a function f（u） of an input u from the local averages are given by a Haar approximation. The question is to know if it holds for higher order approximation methods. To do so, it is necessary to use approximate product operators defined over linear approximation spaces. These products are characterized by a Strang and Fix like condition. An explicit construction of these product operators is exhibited for piecewise polynomial functions, using Hermite interpolation. The averaging relation which holds for the Haar approximation is then recovered when the product is defined by a two point Hermite interpolation.     

Jacobi polynomials used to invert the laplace transform

Given the Laplace transform F(s) of a function f(t), we develop a new algorithm to find an approximation to f(t) by the use of the classical Jacobi polynomials. The main contribution of our work is the development of a new and very effective method to determine the coefficients in the finite series expansion that approximation f(t) in terms of Jacobi polynomials. Some numerical examples are illustrated.