异步电机滑模直接转矩控制器的设计

阐述了采用滑模控制器三点式直接转矩控制逆变器的原理、特点及微机控制方案,建立了系统的数学模型,并给出仿真波形。     

城区10kV配电网中性点接地方式探讨

介绍了１０ ｋ Ｖ 配电网中性点几种主要的接地方式,针对潍坊市城区１０ ｋ Ｖ 配电网结构特点,提出适合该地区１０ ｋ Ｖ 系统的接地方式。     

济钢球团厂减员增效的措施

济钢球团厂在实施减员增效的过程中,打破传统的思维模式,改革传统的设岗定员和分配方式,加强职工技术培训,从而进一步优化了组织结构,调动了广大职工的劳动积极性,不仅实现了减员２０％ 的目标,而且生产指标不断改善。     

开放式双参数核谱数据获取与处理系统

描述的双参数核谱数据获取与处理处理是一个开放式系统,它作为速器质谱数据获取与控制系统的一部分工作于主控机的ＬａｂＶｉｅｗ环境下,该系统获取每个有效事件的死时间小于２０μｓ,活时间测量精确到ｍｓ量级,感兴趣区可设置成椭圆形等多种形式。     

Ergonomics evaluation of a manually operated cassava chipping machine

A manually operated machine for chipping cassava was evaluated. Six farmers took part in the study, with physiological, postural, and subjective measurements being taken. Using the machine resulted in drudgery and postural discomfort. Following an iterative design process and using appropriate anthropometric measurements, an improved, adjustable prototype was developed. This was tested with the six farmers and six novice users. It was found to reduce discomfort and physiological strain, allowed a faster work-rate (with novice users) and was preferred by all users. The study demonstrated how ergonomics can play an important role in reducing drudgery and improving user satisfaction in technology development and transfer in developing countries.     

Tests of a Two-Photon Technique for Measuring Polarization Mode Dispersion With Subfemtosecond Precision

An investigation is made of a recently introduced quantum interferometric method capable of measuring polarization mode dispersion (PMD) on sub-femtosecond scales, without the usual interferometric stability problems associated with such small time scales. The technique makes use of the extreme temporal correlation of orthogonally polarized pairs of photons produced via type-II phase-matched spontaneous parametric down-conversion. When sent into a simple polarization interferometer these photon pairs produce a sharp interference feature seen in the coincidence rate. The PMD of a given sample is determined from the shift of that interference feature as the sample is inserted into the system. The stability and resolution of this technique is shown to be below 0.2 fs. We explore how this precision is improved by reducing the length of the down-conversion crystal and increasing the spectral band pass of the system.     

高速ECL数字判决器线路研究

以电流模法为基础,优化判决器第一、第二级线路结构和元件参数,减少米勒效应对速率的影响,使数字判决器在晶体管特征频率ｆｒ 一定的条件下,转换速率约提高７０％ 。     

中国球形容器建设回顾与展望(续1)

系统介绍中国工业用球形容器自１９５８年开始建造迄今４０年来的历史,综述中国球形容器建造技术水平发展概况,展示达到世界先进技术水平的成果,分析与世界先进技术水平的差距,展望２１世纪中国球形容器建造技术的发展前景。     

A Unitary Analysis of some Voltage and Current Mode Linear Circuits

This paper presents a systematic and unitary analysis of a large class of current and voltage mode circuits based on a series-shunt-like configuration. Four possible OA types are considered for the basic amplifier. The amplifiers have voltage and current input signals and voltage and current outputs. The analysis method is based on the separation of the circuit signal graph in two different paths, one that controls the gain and the other that controls the bandwidth.     

单片开关电源电路的测试方法

单片开关电源的应用越来越广泛,文章首先分析了单片开关电源的功率测量技术,然后给出了主要参数的测试,最后详细介绍了单片开关电源电路的性能测量方法。