Optimization of a door seal structure of a microwave oven using a FDTD method

The optimum door seal configuration to prevent radiation leakage from a microwave oven is still a manufacturing concern. Here, we propose a numerical algorithm to simulate the radiation propagation along a door seal structure using the finite‐difference time domain method, which is used for a priori shielding efficiency tests. The results agree with experimental data. The critical dimensions of the choke structure were found and high shielding is anticipated for a simpler choke structure. Copyright © 2008 John Wiley & Sons, Ltd.     

一起箱变着火事故分析

介绍一起光伏电站箱变着火事故,分析着火原因,并从产品制造和运行维护方面提出针对性建议,对箱变安全运行具有一定的实际意义.     

Simulation of a generator for a wind-power unit

Analysis of excitation systems of generators for wind-power units is carried out, a software package for generator simulation is presented, and the sequence of the generator design is presented.     

Electric potential near a tip of a local discharge on a conductive film

To develop a propagation model of a local discharge on a wet polluted insulator, the authors have examined characteristics of the local discharge on an electrolytic solution simulating the wet polluted insulator surface. The local discharge was propagated on the solution under the impulse voltage. A shape of a contacting surface between the local discharge and the solution has been already obtained by the authors. By using the contacting surface, an electric potential near a tip of the local discharge on a conductive film of 1 mm in thickness was calculated. Furthermore, the potential was measured with a probe. The calculated values and the measured values of the electric potential agreed well regardless of the propagation length of the local discharge, the width of the conductive film, the resistivity of the conductive film, the peak value of the applied voltage and the applied voltage waveform.     

飞机座舱空气调节系统检查仪

文中分析飞机座舱空气调节系统的功能,研制以单片机为核心的检查仪,实现对飞机空调系统工作性能的检测.实际应用表明,该检测设备性能稳定、操作便捷、可靠性高,提高了维修工作的质量和效率,而且该设备对于相关机型具有一定的通用性.     

On the development of a core for a low-power transformer on a basic of wasteless technology

Innovations in critical technology for the production of magnetic materials is considered. On the basis of these innovations, a new design of a low-power transformer is proposed. The operating characteristics of transformers of the pilot and analog design are studied.     

Development of a deceleration control system for a winding machine based on a microcontroller

The development of an automatic deceleration system for a winding machine in a siderurgy factory is presented in this paper. The proposed system controls the speed of a winding machine in order to obtain the optimum stop point in terms of security and fast production. The system is based on a microcontroller and an extremely simple hardware. The system has been tested for two years and results evince a very good mean time between failures.     

Extension of a driving-point and a transfer function to a positive real two-port matrix

A solution is presented to the problem, which arises in two-port modelling, of determining a second driving-point function from a given driving-point function and a transfer function. the given functions must have a common denominator and satisfy the necessary positive real (PR) matrix conditions: the driving-point function must be PR and on the imaginary axis the real part of the transfer function must be zero whenever the real part of the driving-point function is zero. By using a partial fraction expansion and determining a required first-order polynomial, a unique second (minimum) driving-point function is obtained. Examples to illustrate the method are worked out.     

Development of a fault locator for a branch line

Formerly, only pulse radar and the Murray loop bridge could be utilized in a cable fault location method that is applicable to branch lines. Those methods need a terminal connection at the far end. Therefore, it is difficult in fault location involving branch lines. Pulse radar is applicable only for high‐resistance ground faults and the Murray loop bridge is applicable only for low‐resistance ground faults. We have developed current‐detection pulse radar and tested it. In high‐resistance ground fault location, the measured result includes discharge delay error. Therefore, we have proposed an error correction method and confirmed it. In addition, we have designed a new cable fault location method of pulse radar and tested it. © 2000 Scripta Technica, Electr Eng Jpn, 134(2): 19–28, 2001     

一起母线保护不正确动作情况的分析

该文通过对华能大连电厂一次母线故障时BUS1000母线保护动作情况的分析,找出了BUS1000母线保护不正确动作的原因,总结了事故教训,并提出了改进措施.     

Electrodynamics of a resistive sheet moving inside a wave-guide

Contents The interaction between a guided wave and a gliding metal sheet is investigated. The Hertz and Fitzgerald superpotentials are resorted to along with the Lorentz transformation and the overall electromagnetic field is obtained.

---

Wechselwirkung zwischen einer Leitungswelle und einergleitenden Metallscheibe

Übersicht Die Wechselwirkung zwischen einer Leitungs-welle und einer gleitenden Metallscheibe wird untersucht. Das elektromagnetische Feld wird ermittelt an Hand der Lorentz Transformation sowohl wie an Hand der Hertz und Fitzgerald Superpotentialen.

     

电动机自起动电路的设计

介绍了电动机自行起动电路的设计过程及应用.     

某变电站设备支架倾斜事故分析

某变电站地基条件相对较差,且存在膨胀土.设备支架地基原本采用CFG桩复合地基处理,但施工单位将CFG桩改为大直径桩,且人工成孔,设备基础施工完成后约半年,当设备安装完毕试送电时发现,设备基础周边地面有裂隙,支架倾斜,文中通过分析事故原因,进而讨论CFG复合地基处理的机理,并提出相应解决方案.     

变磁阻电机的计算机控制

本文提出并实现了一种变磁阻电机的计算机控制方案。采用计算机实现了变磁阻电机的位置和速度闭环控制。采用高分辨率的增量式光电编码器和相应的硬件接口电路，实现了变磁阻电机转子在定子两个齿之间位移的检测。提出并实现了一种利用超前角实现变磁阻电机力矩控制的方案。     

一起母线保护不正确动作情况的分析

该文通过对华能大连电厂一次母线故障时BUS1 0 0 0母线保护动作情况的分析 ,找出了BUS1 0 0 0母线保护不正确动作的原因 ,总结了事故教训 ,并提出了改进措施     

Control of a tripedal robot walking with a shuffle

This paper describes a control method for a tripedal robot which walks with a shuffle. The robot consists of three electromagnets and three piezoelectric elements. The electromagnet supports the robot as a leg. Two of the three electromagnets adhere to a magnetic floor and the other electromagnet is moved by the deformation of the piezos. The relation between the control waveforms and the robot motion is described theoretically. The theoretical displacement of the robot is calculated. The piezo deformations which move the robot to the destination are obtained. The control waveform is determined by the piezo deformations. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(4): 33–41, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21192     

旋转器与反照器的电路综合

为达到多端口回转器的归一化设计,使其能采用集成电路生产和灵活使用的目标,将阻抗实参数对称矩阵Z分解成Z=R0.Gb.R0T的形式,并且给出了求R0、Gb的方法和用(p+q)端口回转器综合对称实参数阻抗矩阵的电路,将二端口旋转器传输参数矩阵方程转化成阻抗矩阵参数矩阵方程,采用对称实参数阻抗矩阵的分解和(3+2)端口回转器综合二端口旋转器的方法,形成(p+q)端口回转器综合旋转器和反照器电路。且只需调整(p+q)端口回转器外接参数即能适应旋转器和反照器的参数变化,故(p+q)端口回转器能用归一化电路器件实现。因此,旋转器与反照器可用归一化单元电路实现。     

Stability of the natural circulation of a coolant in a horizontal heat exchanger with a ventilation shaft

Results are presented of experimental investigation into the stability of the motion of a liquid in a horizontal heat exchanger provided with a ventilation shaft and inclined toward the ventilation shaft. The process of natural circulation reversal is described, and equations for assessing reversal angle are presented.     

冰箱冷藏室内的湿度研究

我们利用自制装置对冰箱内的湿度进行了系统的研究,并做了蔬菜保鲜对比实验,掌握了大量的第一手材料.现将我们的研究情况总结如下,希望能对相关研究领域起到借鉴作用.