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说明：  目前牵引变压器差动保护原理在某些因素的影响下并不能准确地区分变压器内部故障和外部故障，可能造成保护误动或拒动，危及电气化铁道系统的安全运行。针对这一现状，建立了计及铁芯非线性特性和磁滞效应而又无需铁芯的B－H曲线数据的牵引变压器模型，提出了一种通过参数辩识理论来辩识牵引变压器绕组参数实现牵引变压器微型机保护的方法。该方法能有效地区分内部故障、外部故障和励磁涌流。仿真计算表明了该方法的正确性和可行性。(Traction transformer differential protection principle in the safe operation and can not accurately distinguish between the transformer internal faults and external faults, may be to cause protection mistaken or refuse to move, endangering the electrified railway system under the influence of certain factors. In response to this situation, taking into account the core nonlinear characteristics and hysteresis and without traction transformer core of the B-H curve data model, a the traction transformer winding identification through parameter identification theory parameters to achieve traction transformer microcomputer protection. This method can effectively distinguish internal faults, external faults and magnetizing inrush current. The simulation results show that the correctness and feasibility of the method.)

office使用小诀窍，详细介绍了office组件的各种简单的快捷的操作方式，对于办公室人员是很好的助手。(Office use tips, detailed introduces the office components, different kinds of simple and quick operation is a good helper for the office personnel. )

creat table in microsoft word

全国第一部、国内最好的、全网最热的产品经理公益免费视频教学课程，让你领略产品经理职业的独特魅力。通过浅显易懂的内容引导，真实细致案例解析，让学习者能够清晰的认识和理解“产品经理”的职业特性；并能掌握基本的产品经理技能与思维逻辑，目前已超过60万学习频次！本文档为课程PPT。(The first nationwide, the best, the hottest online product manager public welfare free video teaching course, let you appreciate the unique charm of the product manager profession. Through simple and easy-to-understand content guidance, real and detailed case analysis, so that learners can clearly understand and understand the professional characteristics of the "product manager"; and can grasp the basic product manager skills and logic of thinking, more than 600,000 learning frequency!)

关于编写简洁代码的书籍，讲述了怎样编写高效的代码(Books about writing clean code, tells the story of how to write efficient code)

版图验证工具calibre的rule deck写法教程(Layout verification tool calibre the rule deck writing tutorial)

说明：  C语言动态存储管理的实现及常见问题分析 这是一篇很好的论文(C language implementation of dynamic memory management and frequently asked questions is a good analysis of this paper)

开外网的资料，你可以看看，很容易，按图索骥(open WAP)

一篇关于如何提高单片机运行速度的文章!(An article on how to improve the operating speed of Singlechip article!)

资深工程师写的关于运放噪声分析的文档,对模拟电路工程师很有价值!(Senior engineer to write on the op-amp noise analysis of the document, right analog circuit engineers valuable!)