A Fault Detection Method for Electrohydraulic Switch Machine Based on Oil-Pressure-Signal-Sectionalized Feature Extraction

A turnout switch machine is key equipment in a railway, and its fault condition has an enormous impact on the safety of train operation. Electrohydraulic switch machines are increasingly used in high-speed railways, and how to extract effective fault features from their working condition monitoring signal is a difficult problem. This paper focuses on the sectionalized feature extraction method of the oil pressure signal of the electrohydraulic switch machine and realizes the fault detection of the switch machine based on this method. First, the oil pressure signal is divided into three stages according to the working principle and action process of the switch machine, and multiple features of each stage are extracted. Then the max-relevance and min-redundancy (mRMR) algorithm is applied to select the effective features. Finally, the mini batch k-means method is used to achieve unsupervised fault diagnosis. Through experimental verification, this method can not only derive the best sectionalization mode and feature types of the oil pressure signal, but also achieve the fault diagnosis and the prediction of the status of the electrohydraulic switch machine.     

SPICE模拟纳米技术场效应晶体管圆角效应的建模技术

This paper presents a novel poly(PC)and active(RX)corner rounding modeling approach to SPICE simulations.A set of specially designed structures was used for measurement data collection.PC and RX corner rounding equations have been derived based on an assumption that the corner rounding area is a fragment of a circle.The equations were modified to reflect the gouging effect of physical silicon wafers.The modified general equations were implemented in the SPICE model to enable the model to describe the corner rounding effect.The good fittings between the SPICE model simulation results and the silicon data demonstrated in this paper proved that the designed corner rounding model is practical and accurate.     

基于阵面变形误差的有源相控阵天线电性能分析

有源相控阵天线（Active Phased Array Antenna,APAA）阵面安装产生随机误差,振动冲击、热功耗等引起阵面变形,二者产生的阵面结构变形误差会导致天线电性能的下降,已成为实现高性能APAA的难点之一。将阵面变形误差作为附加的相位因子引入到天线方向图函数中,建立了平面矩形APAA阵面变形误差与电性能之间的结构-电磁耦合模型,并仿真分析了天线阵元个数变化时,阵面变形误差对天线电性能的影响规律。     

SONPMSA系统通信平台关键技术的研究

面向业务的网络性能管理系统是以网络中运行的业务为被管理对象的,而传统网络中间节点的封闭性限制了系统的实现。SONPMSA系统通信平台的设计与实现是通过引入主动代码技术、定义基于应用层实现的主动信包的格式、利用Java的平台无关性解决了主动代码分发机制中关键主动代码的解析和加载两大功能的设计与实现问题。从而解决了面向业务的网络性能管理系统通信平台动态地执行网络业务数据的管理问题。     

LEO卫星移动通信系统空间网络技术分析

在分析LEO卫星星座移动通信系统空间段网络功能和特点的基础上,进行了星座网络路由和交换技术体制的分析和论证,提出了以支持话音业务为主的LEO卫星移动通信系统星座网络路由和交换技术方案。星座网络采用定长信元格式交换体制,采用动态拓扑离散化的拓扑快照静态路由策略。这种静态路由离线计算方式和定长信元交换相结合,提高了网络交换的效率和转发速率。     

无功功率及其相关概念的深度理解

有功功率、无功功率、视在功率和功率因数是电工学中非常重要的基本概念,贯穿电气工程专业课程体系的始终。一些本科教材体系中存在着对这些概念——特别是无功功率概念的模糊引导,导致歧义产生。典型的误解是把电源与负载间存在功率交换视为无功功率产生的必要条件。这种歧义影响了电气工程专业学生及其从业人员对这些概念的理解和应用。本文通过一些典型实例,深入阐释这些概念的内在含义,以期消除歧义,提高教学效果。     

加强激光对抗技术的应用研究

激光设备和激光武器的广泛应用，大大加快了激光对抗技术的研究。探讨了目前激光对抗领域中的激光探测和告警、有源干扰、无源干扰、激光防护等有关技术。     

1~26.5GHz GaAs PIN单刀单掷开关单片

采用GaAs PIN二极管,完成1~26.5 GHz的单刀单掷开关单片的设计、制作。SPST开关单片带内插损小于0.5 dB,驻波优于1.1,隔离度大于27 dB,在10~26.5 GHz,隔离度大于37 dB。开关单片采用MOCVD生长的GaAs纵向PIN二极管材料结构,76 mm GaAs圆片工艺加工制作。     

超精密机床的压电作动器隔振系统研究

压电作动器是振动主动控制中最常用的一种执行机构。文章分析了各种压电作动器的特点及应用范围 ,并用压电陶瓷作动器对超精密机床实施振动主动控制。结果表明 ,该系统应用控制器克服了压电元件的迟滞特性、蠕变特性和非线性后 ,能有效的控制地基振动对超精密机床的影响 ,提高了超精密机床的加工精度     

基于波长调制技术的内腔式气体传感研究

气体传感理论和实验研究已成为当今光纤传感领域的热点之一。波长调制法和有源内腔法是提高气体传感灵敏度的两种有效方式。结合上述两种气体传感方法,构建一个基于波长调制技术的内腔式气体传感系统。讨论气体吸收光谱二次谐波分量与气体浓度之间的函数关系,从理论和实验两方面确定系统的最佳参数。利用提取多条吸收谱线的二次谐波分量,采用平均算法进一步提高系统灵敏度,进行乙炔气体传感的灵敏度可达7.5×10-5。以光纤光栅作为波长参考,建立系统的波长-电压响应曲线,进而检测气体的吸收波长值。进行乙炔气体传感时吸收波长检测的绝对误差不超过0.445 nm。