近年来小型制冷压缩机研究的几个热点问题

本文总结了近年来国内外制冷压缩机的研究与发展状况,包括高效节能、噪声振动、工质替代、新型压缩机等,供国内小型制冷压缩机企业参考.     

新开发的NT4135R和NT6135R通用型柴油机

本文主要介绍南通柴油机股份有限公司开发的NT4135R和NT6135R通用型柴油机的主要技术规格、主要零部件的结构设计与特点、运行性能、用户使用情况等．这种新型的135系列柴油机，通过活塞行程的加长和燃烧过程的改善，达到高功率输出、低燃油消耗的设计要求，实现了使135柴油机性能水平升级的预期目标．     

浅谈水资源管理的发展方向和对策

本文介绍了运城地区水资源管理方面存在的问题，并提出了水资源管理的发展方向和解决问题的对策。     

Decidable call-by-need computations in term rewriting

The theorem of Huet and Lévy stating that for orthogonal rewrite systems (i) every reducible term contains a needed redex and (ii) repeated contraction of needed redexes results in a normal form if the term under consideration has a normal form, forms the basis of all results on optimal normalizing strategies for orthogonal rewrite systems. However, needed redexes are not computable in general. In the paper we show how the use of approximations and elementary tree automata techniques allows one to obtain decidable conditions in a simple and elegant way. Surprisingly, by avoiding complicated concepts like index and sequentiality we are able to cover much larger classes of rewrite systems. We also study modularity aspects of the classes in our hierarchy. It turns out that none of the classes is preserved under signature extension. By imposing various conditions we recover the preservation under signature extension. By imposing some more conditions we are able to strengthen the signature extension results to modularity for disjoint and constructor-sharing combinations.     

一种采用GPS技术的频率标准源的研制

简要介绍了GPS系统的组成及各部分的主要功能,详述了一种采用GPS技术研制的频率标准源的系统构成及各组成部分的工作原理。分析了GPS系统定位误差的因素,重点阐述了采取GPS技术引起频率误差的主要因素,并推算出测量不确定度。给出用比相法和时间隔法对频率标准源进行比对测试的方法和所用的测试设备,对测试结果进行了合理的评价。     

How to reach O.R. Wisdom

This paper identifies the Operations Research (O.R.) problems from a systems view of information, knowledge and understanding. This systems view is examined as a basis for a developmental approach to problem solving and decision making processes. O.R. wisdom lies in achieving a balance between short-and long-term goals through a process of participation and learning.     

促进和谐发展提高我国乙烯工业的竞争力——第十四次全国乙烯年会隆重召开

介绍了第十四次全国乙烯年会的盛况。会议期间，与会代表回顾了我国乙烯工业近两年的发展状况，交流了企业在装置长周期运行、新技术应用及环境保护等方面的经验、体会，讨论了企业关注的焦点及难点问题，提出并展望了我国乙烯工业的目标及前景。     

漫话建筑创作

文章就当前建筑界关心的话题----建筑创作、现时的建筑理论研究工作、中国建筑特色的探索、中国建筑当代的发展、城镇建设面临的态势几个问题,作了简要的阐述,以祈其对繁荣建筑创作有所补益。     

非线性编辑系统架构探索研究

随着信息技术的发展,广播电视技术与计算机技术融合的趋势日益明显,传统的音视频制作正在接受新的挑战,从非线性编辑的概念与特点出发,对合理架构非线性编辑系统应注重的问题、非线性编辑系统的发展趋势进行探讨.