坝基设有截水墙的均质土坝渗流计算新探——赤田水库主坝坝体渗流观测资料分析

根据赤田水库主坝的实测资料,分析得到该坝型浸润线的经验计算公式及其作图方法．     

基于改进齐次多项式技术的离散时间2-D T-S模糊系统的收敛镇定条件

通过利用改进的齐次多项式技术来研究了Roesser型二维T-S模糊系统的镇定设计问题. 首先, 提出了一种用来镇定该二维T-S模糊系统的一种新型非二次控制率, 并且通过应用两种改进的齐次多项式技术得到了保守性更小的镇定条件. 随着所选用的齐次多项式参数依赖矩阵度数的增加, 所得结果的保守性会越来越小. 其次, 为了继续减少保守性, 提出了一种新的右侧松弛变量引入方法, 该方法适合于齐次多项式情形. 最后, 仿真实验验证了所提方法的有效性.     

Stability analysis of discrete-time switched systems: a switched homogeneous Lyapunov function method

This paper addresses the stability issue of discrete-time switched systems with guaranteed dwell-time. The approach of switched homogeneous Lyapunov function of higher order is formally proposed. By means of this approach, a necessary and sufficient condition is established to check the exponential stability of the considered system. With the observation that switching signal is actually arbitrary if the dwell time is one sample time, a necessary and sufficient condition is also presented to verify the exponential stability of switched systems under arbitrary switching signals. Using the augmented argument, a necessary and sufficient exponential stability criterion is given for discrete-time switched systems with delays. A numerical example is provided to show the advantages of the theoretical results.     

H∞ filtering for piecewise homogeneous Markovian jump nonlinear systems

This paper concerns the problem of H_∞ filtering for piecewise homogeneous Markovian jump nonlinear systems. Different from the existing studies in the literatures, the existence of variations in transition rates for Markovian jump nonlinear systems is considered. The purpose of the paper is to design mode-dependent and mode-independent filters, such that the dynamics of the filtering errors are stochastic integral input-to-state stable with H_∞ performance index. Using the linear matrix inequality method and the Lyapunov functional method, sufficient conditions for the solution to the H_∞ filtering problem are derived. Finally, three examples are proposed to illustrate the effectiveness of the given theoretical results.     

机构影响系数统一计算模型

基于机构矩阵型式运动学方程和速度加速度统一模型,讨论了机构运动影响系数通用 计算公式的结构和自动构造算法,得出的一组运动影响系数统一计算公式具有普遍的意义, 并可以方便地由计算机程序自动构造并求解．本文内容建立了机构速度及加速度分析和动力 学自动分析的基础,为通用计算机辅助分析系统的研制创造了先决条件．     

（RbCl）108离子簇均相成核的分子动力学研究

分子动力学模拟测得熔融（RbCl)108离子簇在300K至600K温度时凝固的成核速率大于10^35m^-3s^-1,用均相成核的经典理论加以分析,估算得氯化铷离子簇的固液界面自由能σalT^1.4,用Grunasy提出的扩散界面理论加以分析,估算得扩展界面厚度约为0．195nm,σalT^0.97,2个理论在实验温度范围内没有明显判别,且均能较好地分子动力学模型的结果,但预测的较高温度下的成核速率有比较显著区别,因此进一步地研究将有助于鉴别它们。     

Unexpected products of the allyldiethylamine hydroformylation homogeneously catalyzed by rhodium complexes

Attempts to carry out the hydroformylation of allyldiethylamine homogeneously catalyzed by rhodium complexes led to unexpected formation of N,N,N,N-tetraethyl-1,4-diaminobutane and 4-(diethylamino)-1-butanole as final products. The role of the catalyst on the product formation and the reaction mechanism are briefly discussed.     

STABILIZATION OF A CLASS OF NONLINEAR NON‐MINIMUM PHASE SYSTEMS

This paper tackles the problem of stabilization of a class of non‐minimum phase nonlinear systems which have zero dynamics with an eigenvalue zero of multiplicity 2. By adding some new terms, called cross terms, we are able to generalize the concept of the Lyapunov function with a homogeneous derivative along the trajectory, which was introduced in [4], to produce a suitable Lyapunov function. The Lyapunov function assures that the stability of an approximate system, which consists of some lower order terms of a nonlinear system with an eigenvalue zero of multiplicity 2, implies the stability of the whole system. Applying these to non‐minimum phase zero dynamics of nonlinear systems with such a center, a sufficient condition and a design method of state feedback control are obtained for stabilizing the systems.     

具有多项式型非线性项的大规模随机非线性系统的分散输出反馈镇定

基于齐次占优方法研究 具有多项式型非线性项的大规模随机非线性系统的分散输出反馈镇定问题. 本文的主要贡献在于利用高增益齐次占优方法来解决大规模随机非线性系统的分散控制问题. 这种方法能彻底地去掉传统结果中所要求的线性增长条件, 不仅推广了以前的结果还得到了一些新的结果. 仿真验证了输出反馈控制器的有效性.