Performance improvement of complementary feeders using static transfer switch system

The performance of complementary feeders, running in parallel, can be significantly improved by installing static transfer switches （STSs） at critical locations. We develop the STS control logic, which transfers the critical load from the preferred feeder to the alternate feeder when a voltage sag or a fault occurs on the preferred feeder. A forced commutation technique is proposed and implemented to turn off the preferred feeders＇ thyristor, thus avoiding cross current to flow and minimizing the transfer time. Simulation results show that the forced commutation technique is more effective as compared to the recently proposed time delay technique for STS operation. Two different feeders, namely New Exchange, the preferred feeder, and Sector 1-10/2, the alternate feeder of Islamabad Electric Supply COmpany （IESCO）, Pakistan, have been selected for case studies. The software PSCAD/EMTDC professional package has been used for simulation.     

高炉大钟安装静平衡问题分析

文章采用静平衡分析的方法,给出了高炉大钟的平衡位置和平衡质量的计算方法,可以有效提高大钟的安装速度和质量.     

应用面向对象技术取代全局变量的研究与实现

面向对象技术的封装性与全局变量的使用构成了一对不可调和、严重的矛盾。章以此为出发点，研究了在面向对象编程环境下大量使用全局变量的危害性，剖析了静态成员的访问机制，论证了用静态成员变量取代全局变量的可行性，同时给出了具体的实现方法。     

地球·人脑·太极

本文探索运用太极八卦理论诠释人脑与地球的构同,揭示人类文明与地球结构之间的内在联系.     

浅谈静态联编和动态联编的区别和实现动态联编的条件

多态性是C 面向对象语言的特征之一，多态性是要在调用函数时使用对象的指针或引用。另外，多态性仅用于类层次结构，所以能以一具类中派生另一个类不是多态性的基本条件。虚函数是动态联编的基础，它经过派生之后，在类族中就可以实现运行过程中的多态。动态联编恰是反映C 语言中的多态性的具体体现。本文先阐述了静态联编和动态联编的概念和区别，而后以几个实例说明实现动态联编的条件。     

离散广义双线性系统的无源控制

研究了离散广义双线性系统在有界能量外部输入作用下的无源控制问题,利用线性矩阵不等式和广义代数R iccati不等式,给出离散广义双线性系统容许且严格无源的充分条件,并且基于此条件给出存在状态反馈控制器,使得闭环系统容许且严格无源的充分条件,同时提出了相应的控制器设计.     

Review:Advances in research of stress-assisted corrosion fatigue problem

INTRODUCTION People find that when many glasses and ceramic materials are subject to static loading as well as a chemically reactive environment, they often experi-ence delayed failure due most likely to stress-assisted chemical reactions at the cracks: pre-existing surface flaws grow to a critical length, at which point unstable rapid crack propagation ensues, leading to catastro-phic failure. For a given material and ambient envi-ronment, the lesser the applied stress, the longer the ti…     

中华文化"帝""神"崇拜的数理性起源

"帝""神"崇拜是中华文化的重要现象。本义为花蒂的帝字何以成了至上神的名词,天干地支纪历中的申字何以即是神。对之进行了一种数理性的解释。     

义和团"万宝符衣"考

“万宝符衣”是义和团战士佩带的一种绣有八卦图形的饰物。1898年义和拳起义后,赵三多北上直隶中部传播火种,练红拳的“十八魁”东进山东,与山东的“大刀会”共同战斗。“万宝符衣”是义和拳与大刀会的共同创造,它不仅告诉我们义和团战士是以怎样的方式面对强大的敌人,而且向我们诉说了那发人深思的历史教训。     

Advances in research of stress-assisted corrosion fatigue problem

Ceramic materials are notable for their rigidity, insulation and resistance to hostile environment, Nevertheless, if a stressed ceramic component is exposed to chemical attack, it may suffer from a form of delayed fracture known as static fatigue. From the point of view of a designer, it is clearly desirable to determine the behavior of sub-critical crack growth; the crack path and crack growth rate, as a function of material properties and loading conditions are of particular interest. This paper presents a review of advances in stress assisted corrosion problem in history and its corresponding numerical approaches in the last decades, and finally, comes uo with consideration and crucial suggestions for future work.