A new separation result for a class of quadratic-like systems with application to Euler-Lagrange models

A separation result for some kind of global stabilization via output feedback of a class of nonlinear systems, under the form of some stabilizability by state feedback on the one hand, and some unboundedness observability on the other hand is presented. They allow to design, for any domain of output initial condition, some dynamic output feedback controller achieving global stability. It is also highlighted how disturbance attenuation can further be achieved on the same basis. As an example, the proposed conditions are shown to be satisfied by the class of so-called Euler-Lagrange systems, for which a tracking output feedback control law is thus proposed.     

基于耗散系统实现电力系统励磁鲁棒非线性控制

对单机无穷大系统，通过适当的坐标变换，基于耗散系统的概念，提出了一种新的通过干扰抑制实现的励磁鲁棒非线性控制策略，在实现过程中不需要任何线性化方法．该控制策略可提高系统对动态不确定性的鲁棒性，可抑制干扰对系统的影响．仿真结果表明，提出的励磁控制策略可提高电力系统暂态稳定性．     

低压配电线宽带通信技术

介绍了目前宽带PIC技术所广泛采用的正交频分复用(OFDM)数字调制方法，并分析了如何用OFDM来克服宽带PIC所遇到的噪声干扰和衰减问题，然后简单介绍了电力线宽带通信的国际标准HomePlug 1．0，并介绍了该公司开发的14Mbit／s和45Mbit／s宽带PLC产品及其在我国配电网实际应用中的相关数据。     

上海500kV电网雾闪事故分析

介绍了１９９６年１２月３０～３１日上海电网５００ｋＶ线路发生的４８次雾闪的情况，分析了发生的原因，提出了相应的对策。     

Effect of interactions between voltage and current harmonics on the net harmonic current produced by single phase non-linear loads

The effect of the interaction between both load voltage and current harmonics on the net harmonic current produced by different types of single phase non-linear loads is investigated. Two types of loads are considered: the fluorescent lamps' load and single phase diode bridge rectifiers' load. Studies are done on each load alone and then on the combination of both. The electromagnetic transient program has been used to model these loads. The computer simulations are supported by laboratory testing. The main conclusion of this work is that neglecting the interactions between both voltage and current harmonics will result in incorrect estimation of the harmonic current produced by these loads. Also it is concluded that using a combination of different types of loads can result in a reduction of the current and voltage distortions.     

超高频振动下材料本构关系探析

金属材料在超高频振动作用下的屈服点，硬化度和延伸率都较常规情况明显降低，因此材料的本构关系发生了重大变化。研究金属材料在超高频振动下的特殊行为，建立材料在超高频振动下的本构方程，利用所建立的本构方程解释这些特殊现象，给出了低碳钢试件的实验曲线，通过与理论分析比较证明二者完全相符。     

Disturbance Attenuation and Trajectory Tracking via a Reduced-order Output Feedback Controller for Robot Manipulators

This paper presents a solution to the problem of trajectory tracking with external disturbance attenuation in robotics systems via a reduced-order output feedback controller, without velocity measurement. The proposed control law ensures both semi-global asymptotic stability of the closed-loop system and external disturbance attenuation. The approach is based on the notion of the L₂-gain and requires to solve two algebraic Riccati inequalities. The proposed controller design is illustrated by a simulation example.     

浑水中兆赫频率的声衰减实验研究

文章报道了浑水中的声衰减的实验研究结果，超声波的频率分别为1、2、3、4、5MHz。实验表明：在同一个含沙量M的浑水中，声衰减系数β大致随频率f的增加而线性增加；对同一个频率f，声衰减系数β大致随含沙量M的增加而线性增加；在同一个频率，和相同含沙量M的情况下，声衰减系数β随泥沙粒径的增加而增加。     

Nonlinearity Measurements of High-Power Laser Detectors at NIST

We briefly explain the fundamentals of detector nonlinearity applicable to both electrical and optical nonlinearity measurements. We specifically discuss the attenuation method for optical nonlinearity measurement that the NIST system is based upon, and we review the possible sources of nonlinearity inherent to thermal detectors used with high-power lasers. We also describe, in detail, the NIST nonlinearity measurement system, in which detector responsivity can be measured at wavelengths of 1.06 µm and 10.6 µm, over a power range from 1 W to 1000 W. We present the data processing method used and show measurement results depicting both positive and negative nonlinear behavior. The expanded uncertainty of a typical NIST high-power laser detector calibration including nonlinearity characterization is about 1.3 %.     

辊套材料对铸轧区磁感应强度影响的实验研究

电磁场快速铸轧技术要求辊套材料不仅具有高导热系数、高承载能力和高抗疲劳能力，而且要具有磁场控制能力，保证铸轧区足够的磁感应强度，达到细化晶粒、改善板坯组织性能的目的．本文主要从介质对电磁场的集肤效应、涡流效应、磁场衰减以及屏蔽效应的角度，研究辊套对铸轧区电磁场的影响．