CHAOTIC MOTIONS AND LIMIT CYCLE FLUTTER OF TWO-DIMENSIONAL WING IN SUPERSONIC FLOW

Based on the piston theory of supersonic flow and the energy method, the flutter motion equations of a two-dimensional wing with cubic stiffness in the pitching direction are established. The aeroelastic system contains both structural and aerodynamic nonlinearities. Hopf bifurcation theory is used to analyze the flutter speed of the system. The effects of system parameters on the flutter speed are studied. The 4th order Runge-Kutta method is used to calculate the stable limit cycle responses and chaotic motions of the aeroelastic system. Results show that the number and the stability of equilibrium points of the system vary with the increase of flow speed. Besides the simple limit cycle response of period 1, there are also period-doubling responses and chaotic motions in the flutter system. The route leading to chaos in the aeroelastic model used here is the period-doubling bifurcation. The chaotic motions in the system occur only when the flow speed is higher than the linear divergent speed and the initial condition is very small. Moreover, the flow speed regions in which the system behaves chaos axe very narrow.     

正则多部竞赛图的竞争指数

设D是一个有向图,若存在无向图G满足:(1)G的顶点集与D的顶点集相同;(2)任取D中的两个顶点x,y,其在G中相邻当且仅当存在D中顶点z,使得D中包含一条从x到z的长为m的有向途径和一条从y到z的长为m的有向途径,则称G为D的m步竞争图,记为G=C^m(D).2004年,Cho和Kim首次提出竞争指数的概念.若对于某个正整数r和所有非负整数i,存在最小正整数q,使C^q+i(D)=C^q+i+r(D),则称整数q为D的竞争指数,记为cindex(D).2008年,Kim给出了竞赛图的竞争指数的上界.2009年,Akelbek和Kirkland给出了本原有向图的竞争指数.文中研究并计算了正则多部竞赛图的竞争指数.     

四配位铂磷光发射体结构与光物理性质关系的理论研究（英文）

定量理解光物理过程对于开发新型高效发射极至关重要.优化提升二价铂配合物磷光量子效率是提升基于金属铂有机发光二极管发光效率的关键.本文借助密度泛函理论计算,探讨了一类平面四齿配位二价铂配合物磷光辐射的微观机制,包括自旋轨道耦合积分、辐射寿命、速率常数、跃迁偶极矩和隙间蹿跃通道.综合研究发现,沿着N→Pt方向推电子,可有效屏蔽非辐射跃迁过程,从而提升磷光发射效率.本文将为高效发射器的分子工程学设计提供必要的指导.     

时标上变时滞模糊Cohen-Grossberg神经网络反周期解的指数稳定性

定义一类新的周期函数,建立了时标上模糊Cohen-Grossberg神经网络系统反周期解的存在性和全局指数稳定性的充分条件,最后给出相应的数值例子验证理论结果的有效性.     

关于二个方程同解的条件及其应用

探讨ｆ［ｎ］（ｘ）＝ｘ与ｆ（ｘ）＝ｘ同解的条件，分析一维离散动力系统的周期和混沌问题、并举例说明同解条件在解方程中的应用。     

二阶混合型脉冲微分－积分方程周期边值问题解的存在性

本文利用上下解方法再结合不动点理论给出了二阶混合型脉冲微分－积分方程周期边值问题解的存在性．     

OSCILLATION AND NON-OSCILLATION FOR SECOND-ORDER QUASI-LINEAR DIFFERENCE EQUATIONS

Some oscillation and non-oscillation criteria for second-order quasi-linear difference equations are given. The results in Zhang and Zhou [4] are improved.     

A New Approach to Black hole Spin in X-Ray Binaries

A new approach of detecting the black hole spin in x-ray binaries is proposed based on the model of the coexistence of the Blandford-Znajek （BZ） and magnetic coupling （MC） processes, in which the BZ process is used to power the jet emissions from x-ray binaries, and high frequency quasi-periodic oscillations （QPOs） are explained by a rotating hotspot in the inner region of the accretion disc surrounding a fast-spinning black hole. It is shown that the black hole spins of several x-ray binaries （XTE J1550-564, GRO d1665-40 and GRS 1915＋105） can be constrained in a rather narrow range, provided that QPOs and jets coexist in these sources.     

Time Delay-Enhanced Synchronization and Regularization in Two Coupled Chaotic Neurons

Complete synchronization of two identical chaotic Morris-Lecar (ML) neurons with time-delay coupling is investigated. It is found that the coupled ML neurons may achieve synchronization by an efficient time delay at a low coupling strength. At the same time, the chaotic motion of the coupled neurons may become a regular periodic one during synchronization by the time-delay coupling, that is, the delay time coupling is able to suppress chaos in the process of synchronization. However, the time delay has the effect on enhancement of synchronization and regularization of coupled neurons only in certain coupling strength ranges. Moreover, synchronization of coupled neurons is achieved by time delay after regularization.