Densification involved in the UV-based photosensitivity of silicaglasses and optical fibers

A comprehensive survey of photosensitivity in silica glasses and optical fiber is reviewed. Recent work on understanding the mechanisms contributing to germanium or aluminum doped fiber photosensitivity is discussed within the framework of photoelastic densification models     

Evaluating the impact of CASE: an empirical comparison of retrospective and cross-sectional survey approaches

The purpose of this paper is to evaluate two methods of assessing the productivity and quality impact of Computer Aided Software Engineering (CASE) and Fourth Generation Language (4GL) technologies: (1) by the retrospective method; and (2) the cross-sectional method. Both methods involve the use of questionnaire surveys. Developers' perceptions depend on the context in which they are expressed and this includes expectations about the effectiveness of a given software product. Consequently, it is generally not reliable to base inferences about the relative merits of CASE and 4GLs on a cross-sectional comparison of two separate samples of users. The retrospective method that requires each respondent to directly compare different products is shown to be more reliable. However, there may be scope to employ cross-sectional comparisons of the findings from different samples where both sets of respondents use the same reference point for their judgements, and where numerical rather than verbal rating scales are used to measure perceptions.     

大型现浇钢筋混凝土U型渡槽施工技术

禹门口提水工程干渠上的十几座大型钢筋混凝土渡槽采用现浇混凝土施工方案。经过十几座渡槽的施工及通水检验，证明现浇施工技术与工艺已经成熟。本文就施工中遇到的高大排架外形与垂直度控制、槽身模板制做与固定、模具的空中支撑、运输与入仓办法等做以简单介绍。     

氧化铝陶瓷缺口件循环疲劳及断裂机理

用实验方法研究了Ａｌ＿２Ｏ＿３陶瓷缺口试件在循环载荷作用下的疲劳寿命。结果表明，缺口导致的应力集中效应显著降低了循环疲劳寿命；若用缺口根部最大应力为应力水平，则不同缺口半径陶瓷试件具有相同疲劳断裂规律，说明陶瓷材料的疲劳集中系数和理论应力集中系数相同。本文还分析讨论了陶瓷材料的循环疲劳寿命表达式和循环疲劳断裂机理。     

Presupposition failure — A comedy of errors

Presuppositions of utterances are the pieces of information you convey with an utterance no matter whether your utterance is true or not. We first study presupposition in a very simple framework of updating propositional information, with examples of how presuppositions of complex propositional updates can be calculated. Next we move on to presuppositions and quantification, in the context of a dynamic version of predicate logic, suitably modified to allow for presupposition failure. In both the propositional and the quantificational case, presupposition failure can be viewed as error abortion of procedures. Thus, a dynamic assertion logic which describes the preconditions for error abortion is the suitable tool for analysing presupposition.     

新型实用布线算法──L─M算法

本文提出新型布线算法，集李氏迷宫法与线搜索法的长处为一体，以饱和带法进行动态排序，以线搜索法确定借孔位置，然后用李氏法进行单层布线，获得最佳路径，从而达到线型好，布通率高的效果。     

韩江三角洲海岸变迁遥感调查研究

利用1:10万TM影像，对广东东部韩江三角洲地区的海岸变迁及河道演变进行了调查研究。划分了不同时期的海岸界线和古河道遗迹，提出韩江三角洲的形成是河流动力和海洋动力共同作用的结果，对研究历史海平面变化及环境演变具重要意义。     

场顺序彩色显示器

荫罩CRT受自身结构的限制,要进一步改进其分辨率就有很大的困难。近年已研制成一种获得彩色图像的颇有吸引力的替代品,即场顺序彩色显示器。它由单色CRT和液晶电子色闸组成,称之为LC/CRT系统。液晶电子色闸由液晶π盒及其连用的偏振片组成,可看成是老式机械彩色轮那样的一种电控色带带通滤色片。本文描述了液晶电子色闸的功能及其工作优点,讨论了其可能结构与显示特性。     

940nm高功率激光二极管及线阵

设计并制作出了940 nm无铝有源区高功率激光二极管和激光条.通过MOCVD法生长出应变量子阱材料,器件显示出极好的性能,100μm条宽的激光二极管最大输出功率达800mW(室温),填充因子为17%的激光二极管条发射功率达32 W.