基于混沌的三江平原月降水时间序列分析

三江平原是我国最大的淡水沼泽区,近年来降水的减少是导致湿地减少的一个重要的自然因素.别拉洪河是三江平原上比较有代表性的沼泽性河流.以别拉洪水文站的降水序列为例,通过相空间重构,分别计算了序列的关联维、最大Lyapunov指数以及Kolmogorov熵等几个序列特征量.计算表明:三江平原月降水序列中是存在明显的混沌特征的,这为以后建立三江平原月降水的混沌预测模型提供了理论依据.     

一类耦合非线性振子同步混沌Hopf分岔及其电路仿真

对于一类同时存在扩散耦合和梯度耦合的非线性振子系统, 通过空间傅里叶变换，得到具有不同波矢的各运动模式的相互独立的运动方程. 计算各横截模的Lyapunov指数, 可在耦合参数平面上确定同步混沌的稳定区域. 在稳定区域边界, 一对共轭横截模式失稳，导致同步混沌的Hopf分岔. 对耦合Lorenz振子系统进行了数值模拟，并设计了耦合Lorenz振子系统的电路, 进行耦合振子系统同步混沌Hopf分岔的电路仿真实验. 计算和仿真的结果表明，Hopf分岔的特征频率等于失稳横截模式的振荡频率. 关键词： 耦合非线性振子 同步混沌 横截模式 电路仿真     

Decentralized state-feedback chaotification method of discrete Takagi-Sugeno fuzzy systems

A new chaotification method is proposed for making an arbitrarily given discrete Takagi-Sugeno (TS) fuzzy system chaotic. Based on a given discrete TS fuzzy system, the new chaotification method uses the decentralized state-feedback control and the continuous sawtooth function, instead of the modulo operation, to construct a chaotic nonlinear system,which can generate discrete chaos with the arbitrarily desired amplitude bound. We apply the improved Marotto theorem to mathematically prove that the controlled system is chaotic in the sense of Li and Yorke. In particular, an explicit formula for the computation of chaotification parameters is obtained. A numerical example is used to illustrate the theoretical results.     

一种基于三阶Volterra滤波器的混沌时间序列自适应预测方法

基于Takens的相空间延迟坐标重构,研究了用于混沌信号预测的三阶Volterra滤波器的一种乘积耦合近似实现结构,并应用于典型的低维混沌时间序列和具有高维混沌特性的EEG信号的预测.数值研究表明:这种滤波器结构对于低维混沌时间序列的预测精度可以比二阶Volterra滤波器提高103倍,而且能够较好地对一些具有高维混沌特性的EEG信号进行预测 关键词： 混沌 非线性自适应预测 三阶Volterra滤波器 electroencephalography信号     

代换序列,强诣零性质与混沌

本文的第一部分利用Ｍｏｒｓｅ序列研究并解决了一个代数问题，在第二部分中研究了Ｓｔｕｒｍｉａｎ系统的动力学性质，指出该系统不存在Ｌｉ－Ｙｏｒｋ意义下的混沌集。     

Quantitative characterization of spatiotemporal patterns II

Disorderness of spatiotemporal patterns which are obtained by nonlinear partial differential equations is characterized quantitatively. The mean Lyapunov exponent for a nonlinear partial differential equation is given. The local Lyapunov exponent which is a finite time average of the mean Lyapunov exponent is shown to have close relation to the spatiotemporal patterns. It is suggested that the systems which are described by nonlinear partial differential equations are characterized statistically through the probability distribution function of the local Lyapunov exponent.     

混沌激光对非本征光导型探测器的混沌干扰机制研究

 在唯象理论和二能级模型下，根据级联非线性系统原理，通过求解载流子输运动力学方程的Lyapunov指数，对混沌激光辐照下非本征光电导的混沌干扰机制进行了研究。结果表明：混沌激光能导致非本征光电导本身的混沌现象。     

Weak chaos and anomalous transport: a deterministic approach

We review how transport properties for chaotic dynamical systems may be studied through cycle expansions, and show how anomalies can be quantitatively described by hierarchical sequences of periodic orbits.     

The Mixmaster Universe in Five Dimensions

We consider a five dimensional vacuum cosmology with Bianchi type-IX spatial geometry and an extra non-compact coordinate. Finding a new class of solutions, we examine and rule out the possibility of deterministic chaos. We interpret this result within the context of induced matter theory.     

半导体激光列阵泵浦连续和准连续Nd：YAG激光器稳定输出

用连续输出100mw和脉冲输出200mW的国产双异质结激光二极管(DH-LD)泵浦Nd:YAG激光器,得到稳定的半导体激光泵浦的固体激光器连续输出12mW和10～50kHz重复频率的准连续输出,每个脉冲激光峰值功率20mW,起伏小于1%,与计算结果基本一致.