三峡库区湖北四县水土资源综合开发利用与水土流失防治对策研究

三峡库区湖北宜昌、秭归、兴山、巴东四县幅员面积１１５８９．３平方公里，总人口数１６６．０２万人，三峡水库形成后，淹没土面积７４．４７平方公里，涉及８．９４万人，规划农业生产安置２．８万人。本文以四县土地资源利用现状主和环境容量的分析为基础，进行三峡库区移民安置对水土流失的影响评价，论证综合开发利用水土资源，水土保持与开发性移民相结合，是扩大库区人口环境容量的必由之路，研究制订出移民安置与水土资源的     

AutoCAD二次开发及在包装机械中的应用

针对包装机械的特点，从二次开发的定义出发，分析比较了AutoCAD二次开发的各种手段形式，给出了应用实例。     

A Refinement Calculus for Shared-Variable Parallel and Distributed Programming

Parallel computers have not yet had the expected impact on mainstream computing. Parallelism adds a level of complexity to the programming task that makes it very error-prone. Moreover, a large variety of very different parallel architectures exists. Porting an implementation from one machine to another may require substantial changes. This paper addresses some of these problems by developing a formal basis for the design of parallel programs in the form of a refinement calculus. The calculus allows the stepwise formal derivation of an abstract, low-level implementation from a trusted, high-level specification. The calculus thus helps structuring and documenting the development process. Portability is increased, because the introduction of a machine-dependent feature can be located in the refinement tree. Development efforts above this point in the tree are independent of that feature and are thus reusable. Moreover, the discovery of new, possibly more efficient solutions is facilitated. Last but not least, programs are correct by construction, which obviates the need for difficult debugging. Our programming/specification notation supports fair parallelism, shared-variable and message-passing concurrency, local variables and channels. The calculus rests on a compositional trace semantics that treats shared-variable and message-passing concurrency uniformly. The refinement relation combines a context-sensitive notion of trace inclusion and assumption-commitment reasoning to achieve compositionality. The calculus straddles both concurrency paradigms, that is, a shared-variable program can be refined into a distributed, message-passing program and vice versa. Received July 2001 / Accepted in revised form May 2002     

地震资料精细处理和解释在徐家围子油田的应用

以地震资料精细处理和解释在大庆长垣外围徐家围子油田开发中的成功应用为例，论述了地震地质综合描述技术在地质情况复杂的低、特低渗透油田开发中的应用效果。     

汽车用焊接钢管的发展

介绍了汽车用焊接钢和产品品种，国内皮类管的生产现状及市场需求状况；国外汽车用焊管最新发展情况。建议国内汽车用焊管应该是定点供料，定点生产，设备配套，完善工艺，建立从炼钢，轧制到制管的质量管理体制。     

珠江口门海堤堤型的选择

珠江口站地区面临南海、大陆岸线长４５７ｋｍ，遭受洪水。潮汐、台风的影响，河口滩涂 发育迅速，以约１００ｍ／ａ的速度向大海延伸。随着沿海地区的经济发展，滨海－２ｍ高程以上的滩涂的４万ｈｍ＾２正在和将要建堤围垦和开发利用，原有海堤也亟待加固提高，因此，对珠江口门坝有海堤堤型资料进行收集、整理，分析总结，选择经济可行的海堤堤型，具有重要的现实意义。文中收集了珠江口门的几种主要堤型，通过对各种堤基工程地质     

连续重整装置仿真系统的设计开发

为提高操作人员对连续重整装置开停工及事故处理的熟练程度，并对生产进行指导，采用半机理模型结合设计和现场数据介发的连续重整装置仿真系统已在现场成功投用。介绍了该仿真系统的软硬件结构、动态模型及仿真功能。     

On the ontological expressiveness of information systems analysis and design grammars

Abstract. Information systems analysis and design (ISAD) methodologies provide facilities for describing existing or conceived real-world systems. These facilities are ontologically expressive if they are capable of describing all real-world phenomena completely and clearly. In this paper we formally examine the notion of the ontological expressiveness of a grammar and discuss some of its implications for the design and use of ISAD methodologies. We identify some generic ways in which ontological expressiveness may be undermined in a grammar and some potential consequences of these violations. We also examine ontological expressiveness within the context of some other desirable features that might be considered in the design of ISAD methodologies.     

伺服元件的生产应用及发展趋势

本文概括地介绍了我国自70年代以来伺服元件的生产发展状况、元件的性能特点和应用情况，并分析了今后发展的趋势。