Effective Two-terminal Numerical Algorithm for Overhead Lines Protection

In the paper an effective numerical algorithm for overhead lines protection, particularly fault location and adaptive autoreclosure, is presented. It is based on the two terminal line currents and voltages acquisition. For this purposes the synchronized sampling of all analogue input variables, i.e. the application of the Global Position System/Phasor Measurement Units, was assumed. The algorithm presented is derived in the spectral domain. By this the set of third harmonics variables and line parameters was also used. The prerequisite for successfully adaptive autoreclosure functionality realization was the suitable modelling of the electrical arc. Arc was considered as a source of higher harmonics, distorting by this other electrical variables. In the arc modelling, results of laboratory testing were used. Algorithm is tested for a typical network configuration, assuming by this that the line considered was short enough to neglect its capacitive nature. Based on the results obtained, it is very realistic that the algorithm presented could be implemented in praxis in modern Intelligent Electronic Devices (IEDs).     

基于XML同步媒体技术在远程教育中的应用

远程教育的授课内容点播应用不仅涉及流式媒体技术,还涉及同步媒体技术,需要解决视频/音频与讲稿的同步播放问题。该文研究同步媒体技术在远程教育中的实现,阐述了基于标准化技术规范进行教育资源描述的必要性,分析了同步媒体集成语言SMIL,提出了基于XML的同步媒体解决方案,设计和实现了基于XML同步媒体技术的授课内容点播系统。     

跟踪测量电视系统的同步机

跟踪测量电视系统的同步机信号包括行、场同步脉冲、有效视场信号、电十字丝信号、窗口信号和光标信号等。本文介绍了产生这些信号的三种方法:单片机法、查表法和门阵列法,给出了它们的硬件电路和软件清单,并指出了各自的特点。     

避免同步电动机频繁损坏的技术改进对策

分析了氧化铝一厂同步电动机运行中的故障现象,找出同步电动机频繁损坏的根本原因,针对故障原因对同步电动机的励磁系统进行了改造,取得了很好效果。     

用移动存储设备同步记录地震数据的实现方法

地震勘探中广泛使用的428XL型地震数据采集系统,通常使用磁带机和NAS网络硬盘同步记录地震数据。磁带机读写速度慢,对使用环境要求较高;NAS网络硬盘体积较大,携带不便。各类移动存储设备具有读写速度快、体积小便于携带的优点,利用428XL地震仪的网络功能,经过必要的挂载和设置操作后,可实现将移动存储设备(如U盘、移动硬盘等)用于同步记录地震数据。     

共挤一步法对接焊铝塑复合管生产新工艺

阐述了共挤一步法对接焊铝塑复合管生产工艺过程,对其技术特点进行了重点介绍,为 提高铝塑管产品质量提供了宝贵经验。     

物流演变对企业运行机制的依承与促进--神龙同步供货探索实践

文章通过轿车多品种混流生产中同步供货的个案分析,引出工业工程应用中的共性问题--物流演变对企业运行机制的被动依承和主动促进的辨正关系,强调了观念转变是物流演变的前提条件,物流演变是对企业现行机制的全面挑战,是需要动员方方面面协同配合的系统工程.     

同步缸同步回路系统改进设计

主要介绍某同步液压回路系统的改进设计。在分析原液压系统不足的基础上,对原同步液压回路进行改进,降低了零件加工精度、密封等因素对系统精度的影响,使整个液压系统得到优化,系统的性能明显提高。     

在标准STripFET中集成肖特基二极管以提高数据通信和计算机应用中同步buck转换器的效率

本文采用了先进的strip工艺并在同一块芯片上集成了肖特基二极管的低压功率MOSFETs的工作特性进行了研究。这种新型的MOSFET——肖特基二极管结构可提高应用于移动通信设备中同步buck转换器的效率和可靠性。文中对相关创新的主要技术问题及其优点进行了探讨。并且，为了显示在MOSFET上耦合肖特基二极管对工作特性的显著改进，还对电压调制模块（VRM）的实际工作状态进行了测试。通过与带标准MOSFET的常用的VRM单片电路器件进行比较，可以更显出DC—DC转换器效率的提高效果。文中同时还作了热特性对比。     

Compact factors of countable state Markov shifts

We study continuous shift commuting maps from transitive countable state Markov shifts into compact subshifts. The closure of the image is a coded system. On the other hand, any coded system is the surjective image of some transitive Markov shift, which may be chosen locally compact by construction. These two results yield a formal analogy to “the transitive sofic systems are the subshift factors of transitive shifts of finite type”. Then we consider factor maps which have bounded coding length in some graph presentation (label maps). Now the image has to be synchronized, but not every synchronized system can be obtained in this way. We show various restrictions for a surjective label map to exist.