Radau IIA方法对比例延迟微分方程的渐近稳定性

研究Raudau IIA 方法用于求解比例延迟微分方程时的渐近稳定性。近年来比例延迟微分方程数值解的性质已被数位数学家所研究,他们使用的步长都是定步长,一般情况下将推导出较难分析的递推关系,在本文中出于理论和计算两方面的原因,我们研究强制变步长计算方案,这种解法得到不变阶差分方程。我们证明了Raudau IIA 方法是渐近稳定的。     

STUDY ON AN SIS EPIDEMIC MODEL WITH TIME VARIANT DELAY

In this paper, we study an SIS epidemic model with a time variant delay. By means of Liapunov functional, some sufficient conditions of global stability to endemic equilibrium and disease free equilibrium have been obtained. The influence of time delay on the stability of equilibria is displayed.     

Genetic determinants of individual differences in avoidance learning: Behavioral and endocrine characteristics

Bidirectional genetic selection for good and poor active avoidance learning in a shuttle box has been carried out in three independent laboratories using remarkably similar discrete-trial training procedures. The resulting strains are known as the Roman High and Low Avoidance (RHA and RLA), the Syracuse High and Low Avoidance (SHA and SLA) and the Australian High and Low Avoidance (AHA and ALA) strains, respectively. An additional unidirectionally selected strain, known as the Tokai High Avoider (THA) strain was developed in Japan using a free-operant Sidman avoidance procedure in a Skinner box. This paper reviews the selection of the Syracuse strains, enumerates the various behavioral and endocrine characteristics of the strains, and compares them to the other similarly selected strains. The behavioral work suggests that genetic selection from diverse breeding stocks has resulted in common characteristics that differentiate the strains in the emotional, not learning, domain. The endocrine data, however, are somewhat at odds. The Syracuse strains differentiate one way with respect to endocrine function, and the Roman strains differentiate in the opposite way. We suggest, therefore, that the endocrine correlates are not tightly linked to the avoidance genotype. Genetic analysis of all of the selected strains for both the avoidance phenotype and the endocrine correlates will be needed to test this hypothesis.Preparation of this paper was supported by research grant MH-39230-3 from the National Institute of Mental Health.     

A NOTE ON NONLINEAR ROBUST H∞ ALMOST DISTURBANCE DECOUPLING PROBLEM WITH STABILITY

1 IntroductionThe problem of a1most disturbance deco1lpling with stability(ADDPS fOr short) was orig-inally formulated and solved fOr linear systems by Willems in l98l([ll). Since then variousgeneralizations to nonlinear systems have been xnade(see, fOr e…     

电流变流体的实验研究

电流变流体实质上是一种非导电液体（液相）中加入非极性物质的细小颗粒（固相）而成的悬浮液．本文对悬浮液的空间稳定性和如何提高电流变强度这二个问题展开实验研究．     

基于图像的直接视觉伺服控制器设计与仿真

对于手眼机器人视觉伺服,考虑机器人的运动学及动力学特性,在物体的深度未知及机器人的基坐标系与物体的坐标系之间的相似变换矩阵未定标的情况下,设计了直接视觉伺服控制器,利用自适应算法对深度及上述相似变换矩阵的参数进行在线估计,实现了基于图像误差的定位控制,在系统的工作空间范围内,闭环系统是渐近可稳定的。该方法不需要物体的几何模型及深度的精确值,仿真结果验证了其有效性。     

ROBUST H∞ CONTROL FOR UNCERTAIN NONLINEAR SYSTEMS

This paper studies the robust H∞ disturbance attenuation with internal stability for uncertain nonlinear control systems. By adding one power integrator technique, this paper designs a explicit smooth robust dynamic feedback law while rejecting the disturbance to any specified degree of accuracy. Further, the example and simulation results show the effectiveness of the proposed schemes.     

离层带注浆的稳定性及其改进措施

分析了使用不同浆液在离层带注浆、防止地面沉陷的稳定性，指出使用可固结浆液进行部分充填时，主要决定于浆柱的强度和顶板的结构；而使用湿法注浆时，则可以区分为可流动浆液和被吸附的、结合的浆液；由于前者可以在空间自由流动，在相邻采区开采时，浆液就发生失稳现象，为了改进注浆的稳定性，其措施为：一、选择注浆层位在可崩解的岩层层位并控制用水量；二、通过一定的采矿和注浆方法，使浆液处于自封闭的状态。     

某粘土边坡稳定性分析及支护设计

某办公楼场地北面垂直开挖的土质边坡高5．0—13．5m，需做永久性支护。通过现场勘察、室内试验的信息采集、稳定性分析及支护方案的比较认为，锚杆挡墙是该边坡最合理和经济的支护方案，已被建设方和质检部门采用和实施。     

超载实验在优选化学镀镍工艺参数中的运用

镀液稳定性和沉积速度是衡量化学镍镀液优劣的两大重要参数．基于化学镀镍的基本原理，设计了超载实验．此实验不仅操作简单，而且可以横向比较出不同化学镀液的沉积速度和镀液稳定性．实验结果表明，在聚氨酯泡沫塑料基体上进行化学镀镍，它的最佳工艺参数是pH值为8．0左右，温度控制在45℃左右．