关于广义函数δ(x)的讨论

本文应用《电气子教学学报》之邀约而写，旨在针对一些读者对该韩过去刊出的有关广义函数δ(x）的文章中的质疑，从数学角度提供一些有助于正确认识、处理和运用广义函数的辅助材料。     

基于混沌电路的一种混合噪声调制雷达引信

提出了一种基于混沌电路的随机脉位调制（RPPM）和随机二相码调相（RBCPM）混合调制的雷达引信系统。介绍了该引信波形的数学模型，平均模型函数及引信的实现框图和工作原理，研究了基于混沌电路的混合调制信号的产生方法，这种引信波形不仅具有结构简单和易于处理等特点，而且具有良好的测距和测速性能，以及极低的截获概率和很强的抗干扰特性。     

高炮火控系统滤波器的设计

对目前高炮火力控制系统目标滤波与预测进行了分析与研究．在此基础上结合工程实际设计了一种α-β滤波器．该滤波器的原理是把在连续系统中频率域的要求和在离散系统中Z域的要求转换成时域中在典型信号激励下的时间响应的特征值的要求．从而在时间域中以特征值的要求进行综合．再把综合的结果转换回Z域中．最终得到所确定的α-β滤波器．文中给出了α-β滤波器的Z传递函数．分析了α-β滤波器参数的确定．对α-β滤波器的静态误差进行了研究．对设计方案进行了计算机仿真和实际应用．     

利用DAC设计数控信号发生器

利用数模转换器可构成频率精度高并且可程控的信号发生器。本电路主要由计数器CD4029产生稳定的八路数字信号输出，经数模转换器AD7528输出模拟信号，再经运放变换，从电路的不同的输出端分别实现了三角波、矩形波、正弦波输出，从而实现了信号发生器的数字控制。     

Specification methods for material-handling control algorithms in flexible manufacturing systems

Good methods are needed to specify, test, and debug material-handling control logic. This article surveys a number of representative methods for defining and describing control algorithms for programmable material-handling equipment used in flexible manufacturing systems. The methods are evaluated with regard to their suitability for communication between people and as bases for interfaces to automatic program generators. It is concluded that no single method is entirely satisfactory. Three methods (position diagrams, function block diagrams, and operation networks) have potential to be combined into an effective hybrid approach that minimizes the need for the user to switch between various conceptual models.     

Epidemiology of Trauma and Posttraumatic Stress Disorder in Mexico.

Prevalence rates of trauma and posttraumatic stress disorder (PTSD) were estimated from a probability sample of 2,509 adults from 4 cities in Mexico. PTSD was assessed according to Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994) criteria using the Composite International Diagnostic Interview (CIDI; WHO, 1997). Lifetime prevalence of exposure and PTSD were 76% and 11.2%, respectively. Risk for PTSD was highest in Oaxaca (the poorest city), persons of lower socioeconomic status, and women. Conditional risk for PTSD was highest following sexual violence, but nonsexual violence and traumatic bereavement had greater overall impact because of their frequency. Of lifetime cases, 62% became chronic; only 42% received medical or professional care. The research demonstrates the importance of expanding the epidemiologic research base on trauma to include developing countries around the world. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

三角函数型增长曲线预测油田开发指标

提出了用三角函数表示的一类用于油田开发指标预测的增长曲线共6条，从而进一步完善和丰富了现有的增长曲线法。提出和推导了它们的Np-t、Qt-t、Qt-Np关系式、（Np/NRmax)Qtmax准数计算式以及参数求解式。其特片研究表明，它们特征相近；（Np/NRamx)Qtmax变化范围为0-0.36785，属于峰值产量出现在油田开发初期的情况，其Qt-Np关系为一不对称的拱形曲线。提出了求取曲线参数的过原点重复线性回归法。双河油田的实例表明该方法有一定实用价值。     

浅析异步电机电子软起动器的现状和展望

本文在分析异步电机电子软起动器的现状和展望的基础上，以一个当前正在设计完善的电子软起动器为例，基本说明新型电子软起动器的特点和结构功能。     

Optimization by random search with jumps

We give a random optimization (RO) algorithm to optimize a real‐valued function of n real variables. During the optimization process, interpolation points are examined to follow valleys, and jumps to new starting points are executed to avoid numerous iterations in local minima. Convergence with probability one to the global minimum of a function is proved. The proposed RO method is a simple, derivative‐free and computationally moderate algorithm, with excellent performance compared to other RO methods. Seven functions, which are commonly used to test the performance of optimization methods, are used to evaluate the performance of the RO algorithm given here. Copyright © 2004 John Wiley & Sons, Ltd.