Experimental study of crystal anisotropy based on ultra-precision cylindrical turning of single-crystal calcium fluoride

To realize ultimately efficient signal processing, it is necessary to replace electrical signal processing circuits with optical ones. The optical micro-resonator, which localizes light at a certain spot, is an essential component in optical signal processing. Single-crystal calcium fluoride (CaF₂) is the most suitable material for a highly efficient optical micro-resonator. The CaF₂ resonator can only be manufactured by ultra-precision machining processes, because its crystal anisotropy does not allow the application of chemical etching. However, the optical micro-resonator's performance depends definitely on the surface integrity.This study investigated the relationship between surface quality after ultra-precision machining and crystal anisotropy. Firstly, crack initiation was investigated on the (1 0 0), (1 1 0), and (1 1 1) planes using the micro-Vickers hardness test. Secondly, brittle-ductile transition was investigated by orthogonal cutting tests. Finally, cutting performance of cylindrical turning was evaluated, which could be a suitable method for manufacturing the CaF₂ resonator. The most difficult point in cylindrical turning of CaF₂ is that the crystalline plane and cutting direction vary continuously. In order to manufacture the CaF₂ optical micro-resonator more efficiently, analysis was conducted on crack initiation and surface quality of all crystallographic orientations from the perspective of slip system and cleavage.     

一个计算机动画转头模型

本文提出一个用于计算机动画的转头模型。它利用头部的正面和侧面形象来构造出头的三维结构形象，然后按指定的旋转轴旋转该结构，经过边缘轮廓提取及隐线消除，最终得到正确的转头过程序列画面。     

面向21世纪课程教材对地方综合大学电工学教学改革的影响--广西大学使用面向21世纪电工学课程系列教材的实践与探索

阐述了我校使用“面向21世纪”电工学课程系列教材的实践与探索过程，以及对我校电工学教学所产生的转折性影响和积极的导向作用，最后对教材提出了几点建议。     

以入世为契机,进一步推进电力科研院所企业化转制

我国入世和融入经济全球化，将给中国经济运行的大环境带来深刻变化，科技事业也面临着全新挑战。电力科研所实行企业化转制，与国际接轨，按照国际规则办事势在必行。作者作为电力科研单位的一把手就电力科研院所的企业化转制阐述了个人的观点。转制必须有利于回忆科技创新和高新技术产品的开发；必须有利于抓紧培养和造就复合型人才队伍；必须有利于更好地为电网、为发供电企业提供规范化、制度化、长期化和现代化的全方位服务。     

发动机扭矩与转速关系经验公式试验研究

在对发动机外特性曲线扭矩与转速实验数据分析的基础上，对原有的经验公式进行了分析、改进，提出了新的经验公式．由这一经验公式所计算的数值，在最大扭矩与最大功率点之间，可与实验数据拟合得很好．与原经验曲线相比，新经验曲线与实验曲线的离差可下降50％以上．     

湘钢220KV备用电源自投方式商榷

针对湘钢三中央变电站２２０ｋＶ备用电源自投装置存在的问题，提出了新的方式和设想．分析采用新的方式后，停电时间由３．５ｓ缩短至０．０４～０．０９ｓ的可行性．同时还提出在ＳＦ６断路器的变电站，自投装置应采用的方式．     

差齿原理在推床同步调整技术中的应用

文章应用差齿原理在冶金设备初轧机推拉床实施转角性微调技术，以达到初轧机机前与机后推拉床同步调整效果．实践证明，效果显著，适用面广，且操作简单、方便经济．     

Surface integrity in finish hard turning of case-hardened steels

Highly stressed steel components, e.g., gears and bearing parts, are appropriate applications for hard turning. Therefore, the process effects on significant engineering properties of work materials have to be carefully analyzed. Roughness, residual stresses, and white layers as parts of surface integrity, are functions of the machining parameters and of the cuttability of the cutting edge, i.e. of the tool wear.The aim of this work was to study the influence of feed rate, cutting speed, and tool wear on the effects induced by hard turning on case-hardened 27MnCr5 gear conebrakes and to point out the technical limitations in mass production.     

Influence of the stress,strain, and temperature on the surface roughness of an AlSl 52100 steel due to an orthogonal cut

In recent years, the finite element method (FEM) has become the main tool for simulating the metal cutting process because research based on trial and error is time consuming and requires high investment. Early studies were done by different investigators. In this research AISI 52100, hardened steel (62 HRC) was selected for an orthogonal machining process as well as metal cutting simulation using the software DEFORM-2D. This software is based on a forging process and has been adapted to an orthogonal machining process. The results of simulated cutting forces were compared with experimental cutting force data to validate the orthogonal cut simulation. Also, the surface roughness was measured, and the influence of the stress, strain, and temperature on the surface roughness was studied.