End-User Computing in a CASE Environment

Computer-aided software engineering (CASE) tools are currently being used by IS professionals rather than by users. No matter how effective these tools may be, however, they will not be able to assist in the reduction of application backlogs without supporting user-driven applications. This article examines characteristics of a CASE environment from the various perspectives of decision support, identifies the advantages and limitations of end-user computing in this environment, and suggests how IS managers can realize the potentials of CASE for user applications.     

A Built-in Self-Test Scheme with Diagnostics Support for Embedded SRAM

In this paper we propose a novel built-in self-test (BIST) design for embedded SRAM cores. Our contribution includes a compact and efficient BIST circuit with diagnosis support and an automatic diagnostic system. The diagnosis module of our BIST circuit can capture the error syndromes as well as fault locations for the purposes of repair and fault/failure analysis. In addition, our design provides programmability for custom March algorithms with lower hardware cost. The combination of the on-line programming mode and diagnostic system dramatically reduces the effort in design debugging and yield enhancement. We have designed and implemented test chips with our BIST design. Experimental results show that the area overhead of the proposed BIST design is only 2.4% for a 128 KB SRAM, and 0.65% for a 2 MB one.     

中国电子商务思考

网络经济持续走低，但电子商务的发展大方向是不会改变的。在中国，目前的主要问题是宽带网的重复建设、认证机构建设缺乏有效监管、电子商务立法滞后、物流配送系统不完善、标准化问题成为电子商务发展的障碍等，当前应做的主要是：政策的宏观引导、示范推广、加强对宽带网和认证机构建设的监管等。     

基于DOCSIS标准的HFC数据加密算法的分析

基于DOCSIS标准的增强型基线保密性接口（BPI＋）采用56bit DES加密分组数据，采用二密钥三重DES加密通信量加密密钥。这种多重加密技术的应用为HFC网络的数据传输提供了相当于或更好于专线级的网络安全与加密性能。     

Interfacial segregation of Ti in the brazing of diamond grits onto a steel substrate using a Cu-Sn-Ti brazing alloy

Diamond grits were brazed onto a steel substrate using a prealloyed Cu-10Sn-15Ti (wt pct) brazing alloy at 925 °C and 1050 °C. Due to the relatively high concentration of Ti in the brazing alloy, the braze matrix exhibited a composite structure, composed of β-(Cu,Sn), a Cu-based solid solution, and various intermetallic compounds with different morphologies. The reaction of Ti with diamond yielded a continuous TiC layer on the surfaces of the diamond grits. On top of the TiC growth front, an intermetallic compound, composed of Sn and Ti, nucleated and grew into a randomly interwoven fine lacey structure. An interfacial structure developed as the interwoven fine lacey phase was semicoherently bonded to the TiC layer, with the Cu-based braze matrix filling its interstices. The thickness of such a composite layer was increased linearly with the square root of isothermal holding time at 925 °C, complying with the law of a diffusion-controlled process. However, at 1050 °C, the segregation behavior of Ti and Sn to the interfaces between the TiC layer and the braze matrix diminished, due to the increased solubility of Ti in the Cu-based liquid phase. The enhanced dissolution of Ti in the Cu-based liquid phase at 1050 °C also caused the precipitation of rod-like CuTi with an average diameter of about 0.2 μm during cooling. SnTi₃ was the predominant intermetallic compound and existed in three different forms in the braze matrix. It existed as interconnected grains of large size which either floated to the surface of the braze matrix or grew into faceted grains. It also exhibited a nail-like structure with a mean diameter of about 1 μm for the rod section and a lamellar structure arising from a eutectic reaction during cooling.     

喷射轧制Fe-4.5%Si硅钢片的组织和性能

采用喷射成形和轧制工艺制备了厚度为0.5mm的Fe-4.5%Si高硅钢片，并对其密度、显微组织和电磁性能进行了测试分析，研究结果表明：在最佳的喷射成形和轧制工艺条件下，所制备硅钢片的磁感应强度B25为1.544T、B50为1.641T；铁损P1050为1.437W/kg、P1550为3.43W/kg，说明喷射成形轧制技术可以制备出高磁感应强度、低铁损的高硅钢片。     

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。     

X60管线钢疲劳特性的研究

利用2、4和14mm的X60钢紧凑拉伸试样进行同样应力水平、固定应力比（R＝0．1）的疲劳裂纹扩展试验，揭示出高韧性管道钢的疲劳裂纹扩展存在显著的厚度效应。由于应力水平低，相应的离面应力也低，不足以导致分层开裂，因此，裂纹端部的三维应力约束随厚度增加而增大。4mm试样的疲劳裂纹速率远高于2mm试样，但厚度再增大，裂纹扩展速率不再有显著变化。进一步对表面裂纹试样进行疲劳裂纹扩展试验，并用勾线法纪录裂纹扩展情况，利用穿透裂纹的da/dN-ΔK曲线预测表面裂纹扩展，用2mm厚试样的数据控制裂纹表面长度的扩展，用14mm厚试样的数据控制裂纹底部沿厚度方面的扩展，得到了与表面裂纹扩展实验吻合很好的预测结果。     

基于POSC的测井曲线数据存储管理系统

在基于POSC标准的基础上，分析了POSC EPICENTER数据模型，对油田中普遍使用的LS716测井大块数据在磁盘和远程自动磁带库之间实现了一体化的数据管理，开发了数据加载，数据删除，头信息浏览线回施行能模块。该系统特点是，管理信息加载到POSC数据仓中，而真正的数据体以外部数据文件的形式存放，使得大块数据的加载和提取速度大大提高，同时，在数据仓库和远程带库之间实现了一体化的数据管理。     

祝贺《农机推广与安全》杂志全新出版

随着农村经济的发展和产业结构的调整,广大农民在生产中对新技术及农机具产品的需求日益多样化,特别是农业产前和产后适用机械装备的应用,逐步显现出了新的市场前景,农业机械化的发展已经逐步深入到农业生产的各个环节和农村经济建设的各个领域.因此,农机的新技术推广与安全运用,是在新形势下促进农机化健康发展的重要任务.