菲涅耳照明透镜设计

在照明灯具中菲涅耳透镜代替平凸透镜有许多优点。本文描述了菲涅耳照明透镜的设计原理、计算方法及参数选择。所获得的菲涅耳照明透镜有非常好的性能。文中给出了测试结果。     

Whose attitudes to which aspects of work? or Cool media for high participation

Current approaches to the assessment of job attitudes—for use in job redesign—seem to centre upon the importance of job characteristics, such as those within the Job Characteristics Model. Data collection is largely through well-founded, repeatable, formal questionnaires. It is argued that a broader, ergonomics perspective is required, stressing the importance of job holders' attitudes to the technology being used, the physical environment and workplace, and procedures in support of work, such as training. Furthermore, if we wish to promote the participation of those whose work is being redesigned, the traditional and scientifically respectable questionnaire may not be the correct instrument. Data gathered by means of informal semi-structured discussion may better reflect the concerns and priorities of the people doing the work. Perhaps, to paraphrase Marshall McLuhan, formal job attitude instruments used alone are 'hot media', in the sense of being well-filled with data but low in participation. Informal discussion methods could be seen then as a 'cool medium', high in participation or completion by the audience (McLuhan 1964, pp. 22-23).     

强化华南地区在拓展与东南亚经济合作关系中的地位与作用

东南亚是近年来世界上经济增长较快的地区,在亚太甚至整个世界经济新格局中占有重要地位。本文从东南亚在世界经济新格局中所处的地位、东南亚经济和产业结构的变化与中国经济的互补性、华南地区在中国与东南亚经贸关系中的地位和作用论述开始,逐步深入,最后具体分析了华南地区在加强与东南亚经济合作中所应采取的对策。     

互连网络拓扑优化设计

论述了互连网络拓扑优化设计问题,建立了必要的数学模型,该数学模型是一个非线性组合优化问题,它属于NP—完备类问题。采取拉格朗日松弛法、次梯度迭代算法和启发式算法,得出最优下确界和结论。     

AN ALGORITHM FOR THE DESIGN OF 2? FACTORIAL EXPERIMENTS ON CONTINUOUS PROCESSES

Saunders & Eccleston (1992) presented an approach to the design of 2-level factorial experiments for continuous processes. It determined sets of contrasts between the observations that could be well estimated, and then selected a design so that those contrasts estimated the parameters of interest. This paper shows that a well-estimated contrast must have a large number of changes of sign or level, and also be ‘paired’ in a particular sense. It develops an algorithm which constructs designs that must have a large number of changes of sign, evenly spread among the contrasts and optimal or near optimal. When such designs exist they are often preferable to those produced by the reverse foldover algorithm of Cheng & Steinberg (1991).     

以模拟为基础的氨合成塔内件优化设计计算

本文提出以模拟为基础，以氨净值为目标函数，以上绝热层，冷管层，下绝热层高度为调优变量的氨合成塔内件优化设计计算方法，并编制了相应的计算程序，实例表明本法具有简单、可靠、快速等特点。     

A quest for certain linear spaces on thirty points

We investigate the structure of linear spaces on 30 points which have no lines of sizes 2, 3, 6, 30.     

On the block structure of proper block designs

In this paper we consider proper block designs and derive an upper bound for the number of blocks which can have a fixed number of symbols common with a given block of the design. To arrive at the desired bound, a generalization of an integer programming theorem due to Bush (1976) is first obtained. The integer programming theorem is then used to derive the main result of this paper. The bound given here is then compared with a similar bound obtained by Kageyama and Tsuji (1977).     

韩国新一轮产业结构调整及其对我国经济结构调整的启示

20世纪90年代以来,韩国经济发展速度放慢的一个重要原因,就是产业结构调整的滞后。目前,韩国正在进行新一轮的产业结构调整,并且初见成效。研究并借鉴韩国产业结构调整的得失,对正处于经济结构调整关键时期的中国来说,大有裨益。     

以人为本:英语提高阶段课程体系改革的思考——清华大学英语选修课课程设置学生问卷调查分析

清华大学外语系大学英语选修课教研室于2003年秋季学期在306名本科生中做了一次选修课课程设置的问卷调查。该问卷调查试图从选课目的、课程总体收获、具体学习收获、学习需求和存在问题等方面了解学生对英语提高阶段选修课的反馈意见。文章将对调查数据所展示的重要信息进行概要的介绍和分析,并就如何在课程设置改革中体现“以人为本”的思想提出了一些设想和建议。