捕食者和食饵均带有扩散的随机捕食-食饵模型动力学分析

考虑了斑块环境下捕食者种群和食饵种群分别在n个斑块扩散的随机捕食 食饵模型.利用Lyapunov函数法证明了对任意给定的初始值,随机系统全局正解的存在唯一性,并对其进行了有界性分析.此外给出了食饵种群及整个系统灭绝的充分条件.最后通过数值模拟验证了所得理论的正确性.     

具有反馈控制和Beddington-DeAngelis功能性反应的非自治扩散模型的概周期解

讨论了一类具有反馈控制和B edd ington-D eA ngelis功能性反应的非自治捕食-食饵扩散模型,其中食饵可以在两个斑块有限制地扩散,但对捕食者来说,斑块间的扩散不受限制.本文结合运用Lyapunov函数,得到该模型存在唯一的全局渐进稳定的正概周期解的条件.     

生态扩散系统全局渐近稳定的条件

本文研究一类带扩散的非自治捕食系统,该系统由ｎ个斑块组成,食饵种群可以在ｎ个斑块之间扩散,而捕食者种群限定在一个斑块不能扩散．得到系统持续生存和全局渐近稳定的条件．     

Allee效应下的一类捕食-食饵系统的动力分析

建立了一个食饵具有一个保护的区域和非保护区域的捕食-食饵模型,在考虑环境制约的情况下,同时考虑了保护区的食饵具有Allee效应.根据食饵与捕食者的生物意义以及一些参数的快慢两个时间尺度,将系统分为快速系统和慢速系统.通过动力分析,给出了慢速系统平衡点的存在性、全局稳定性、Hopf分支以及极限环存在的条件,并通过数值分析及数值模拟加以验证结果表明,Allee效应的存在改变了两物种的共存的条件,使系统动力行为更为复杂.     

具有两个食饵趋化项的一个Ronsenzwing-MacArthur捕食食饵模型的全局分歧

文章研究在诺伊曼边值条件下具有两个食饵趋向的一般Ronsenzwing-MacArthur捕食食饵模型的稳态分歧分析. 其结果展示了在具有两个食饵趋向的捕食食饵系统中丰富的动力学性质.     

具有收获和阶段结构的时滞脉冲的捕食-食饵模型

研究了食饵分布在不同斑块,捕食者具有阶段结构和收获的时滞脉冲的捕食-食饵模型.利用离散动力系统的频闪映射,得到了捕食者灭绝周期解的存在性和它的精确表达式.使用比较原理,得到了捕食者灭绝周期解全局渐近稳定的充分条件和系统的持久性.最后,用Matlab软件进行数值仿真验证了获得的结果.     

带有扩散、脉冲和时滞的非自治捕食系统的正周期解

考虑了一类食饵在斑块环境中扩散具有脉冲和时滞的捕食系统，通过灵活地运用Gaines和Mawhin的连续拓扑度定理，获得了一系列易验证的正周期解存在的充分条件．     

一类具有分段常数变量的三维食饵捕食者系统的稳定性和分支行为

本文研究一类具有分段常数变量的三维食饵-捕食者系统的稳定性和分支行为,该系统由一个捕食者和两个食饵构成,其中一个食饵可由捕食者对另一个食饵的捕食行为中获益.首先通过计算得到三维食饵-捕食者系统对应的差分模型,其次通过选择合适的参数讨论边界和正平衡点的存在性,进而利用线性稳定性理论讨论平衡点局部渐近稳定的充分条件.将两个食饵种群的出生率以及最大环境容纳量作为分支参数,使用分支理论研究差分模型在平衡点处产生翻转分支、Neimark-Sacker分支、折-翻转分支和1:2共振分支的充分条件.最后通过数值模拟验证了理论分析的正确性.     

具有脉冲效应非自治捕食系统的研究

研究了具有脉冲效应的非自治捕食系统,该系统是两个具有互惠关系的食饵种群被一个捕食种群捕食.利用重合度理论证明系统正周期解的存在性.     

Holling IV捕食-食饵时滞系统的多个周期解

应用重合度定理研究了一类具有Holling IV类功能性反应时滞捕食-食饵系统的周期解的存在性问题,建立了该系统具有至少两个正周期解的充分条件．     

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.     

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.     

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.     

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     

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     

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).     

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.     

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.