Global complete observability and output-to-state stability imply the existence of a globally convergent observer

We consider systems which are globally completely observable and output-to-state stable. The former property guarantees the existence of coordinates such that the dynamics can be expressed in observability form. The latter property guarantees the existence of a state norm observer and therefore the possibility of bounding any continuous state functions. Both properties allow to conceptually build an observer from an approximation of an exponentially attractive invariant manifold in the space of the system state and an output driven dynamic extension. The proposed observer provides convergence to zero of the estimation error within the domain of definition of the solutions. The work of A. Astolfi is partly supported by the Leverhulme Trust.     

连轧机用人字轮齿轴断裂失效分析

用宏观断口分析、化学检验、力学性能测定、低倍检查、金相组织及夹杂物评定鉴别、受力分析及强度寿命定量估算的方法，对人字轮被动齿轴端断裂失效原因进行分析，并提出改进措施。     

CPAM的分子参数对页岩抑制性的影响

通过合成的一系列具有不同分子量的聚丙烯酰胺的阳离子化制得具有不同分子参数的阳离子聚丙烯酰胺（ＣＰＡＭ）。经评价实验就分子参数对页岩抑制性的影响进行研究     

强折射轴对称流场的干涉再现方法

利用光学方法测量气体状态参数的关键在于确定气体折射率场的变化。光线通过稳定的非均匀折射率场时发生偏折，并且在强折射对称场中会产生交叉，使得条纹位移量的判读困难。本文首先分析了光线在轴对称折射率场中的偏折效应，在此基础上，给出了一种利用成像透镜对强折射轴对称场中折射率的干涉再现方法。该方法与其它方法相比较能够精确地确定折射率ｎ（ｒ）的值。     

Stabilization of inter-area and/or oscillatory modes in large-scale power system by voltage impedance power system (VIPS) apparatus based on decentralized control scheme

New technologies such as power electronics have made it possible to change continuously the impedance of a power system not only to control power flow but also to enhance stability. A power system incorporating a variable impedance apparatus such as a variable series capacitor (VSrC) and high-speed phase shifter (HSPS) is called VIPS (Variable Impedance Power System) by the authors. This paper proposes a novel control method of VIPS apparatus such as VSrC and HSPS installed at an interconnecting point for stabilizing inter-area unstable and/or oscillatory modes. The proposed design method of the control system is a kind of hierarchical decentralized control method of a large-scale power system based on a Lyapunov function. Under the proposed control scheme, each subsystem can be stabilized independently by local controllers such as AVR, speed governor and PSS, and then the whole interconnected system can be stabilized by VIPS apparatus taking into account interactions between subsystems. The effectiveness and robustness of the VIPS apparatus control are shown by numerical examples with model systems including a large-scale power system.     

Electrochemical Aspects of Electroosmotic Dewatering of Clay Suspensions

An attempt is made to elucidate the electrochemical aspects of the electroosmotic dewatering (EOD) of clays as reported in some recent work, especially that on interrupted DC power electroosmotic dewatering published by Rabie, Mujumdar and Weber (2). These authors showed that the dewatering by EOD stops after the DC power has been on for several minutes or hours; on interruption of their power and on short-circuiting of the electrodes, conditions can be created again for some further dewatering by DC power EOD. This discovery, of Rabie et al. is interpreted as a fuel cell effect and it is shown that it affords clues to several other electrochemical strategies for the possible enhancement of the efficiency of the EOD by DC power.

Further, the open circuit potentials observed by Rabie et al. (2) on the interruption of DC power are given an electrochemical interpretation which leads to quantitative estimates in agreement with the experimental values.     

高速冷带轧机垂直自激振动稳定性分析的数值计算方法

本文在充分考虑轧机垂直振动过程中辊缝非线性的基础上，利用轧制理论方程和机械振动理论中的能量判据，给出了更精确的分析高速冷轧机垂直自激振动稳定性的数值计算方法。     

线性时变系统的区间稳定性与鲁棒稳定性

本文应用向量比较定理研究线性时变系统的区间稳定性和具非线性时变摄动的线性时变系统的鲁棒稳定性，所得的新结果包含文献的一些主要结果作为特例，本文的研究方法说明向量比较方法是分析区间稳定性和鲁棒稳定性的一种自然而有力的工具。     

Pi-coefficient analysis of update algorithms for adaptive systems

This paper finds the appropriate pi-coefficients for a parameter estimation adaptive system and uses them to analyze the stability of two estimation algorithms. The estimation error dynamics of the system are modeled by a linear time-invariant subsystem and a nonlinear time-varying update law in a feedback loop. Then the so-called max-p problems are formulated and solved to obtain the pi-coefficients for the linear subsystem and nonlinear update low. For the investigated system, the quantitative results show that the least-squares update algorithm has larger stability range than that of the gradient algorithm, and the σ-modification scheme gives larger stability ranges for both algorithms.     

β－C_2S固溶体稳定的热力学研究

从热力学理论出发，利用Ｘ射线衍射定性和定量的方法，对β－Ｃ＿２Ｓ固溶体的稳定性进行了分析和研究。经热力学理论推导得出β－Ｃ＿２Ｓ稳定的热力学条件，即掺入的微量元素的化学位μ＿ｉ须小于β－Ｃ＿２Ｓ的反应自由焓△Ｇ＿β，μ＿ｉ＜△Ｇ＿β．并定量地计算出一种微量元素稳定β－Ｃ＿２Ｓ的临界掺加量为；多种微量元素对β－Ｃ＿２Ｓ的稳定性判断条件为：