过热度对电脉冲孕育处理Al-5%CU合金凝固组织的影响

研究了不同的过热度对电脉冲孕育处理Al-5％Cu合金凝同组织的影响。实验结果表明：不同的过热度下对Al-5％Cu合金进行电脉冲处理，合金凝同组织均得到一定程度的细化，但过热度不同时细化效果不同。一定温度范围内．熔体温度为740℃时，电脉冲孕育处理细化的效果最好，并分析了过热度影响电脉冲孕育处理Al-5％Cu合金凝同组织的机制。     

滑轨升降拉钢台架的结构、强度、钢度分析

介绍了攀钢轨梁厂钢轨收集装置——滑轨升降式拉钢台架的结构,并计算了主要受力构件滑轨的强度和刚度。     

DNC系统在航天制造企业的实施和应用

介绍了DNC（Distributed Numerical Control分布式数字控制）机床联网系统的功能特点以及上海航天设备制造总厂实施DNC系统的详细过程。     

冶金企业面临的严峻局面及今后工作重点

阐述了冶金企业在当前的严峻形势下，要求得生存必须转变传统观念。并提出“九五”期间的工作重点是：节能降耗、调整品种结构、提高生产率及加强决策管理。重点论述了实现节能降耗应抓好的四项工作：连铸坯一火成材与热装直轧，轧钢炉窑节能技术，轧机主传动交流调速技术及控制冷却技术。     

一种基于RSA安全可行的（t，n）门限签名方案*

分析了大多数RSA门限群签名方案存在的缺陷,RSA的模数是n,φ(n)是秘密参数,参加部分签名的成员无法知晓,求Lagrange相关系数存在困难,也为建立门限RSA密码体制带来困难.提出一种新的方案以克服上述困难,通过求ai无须在求Lagrange相关系数时进行求逆运算,使该方案在保证安全的前提下变得可行实用.     

基于再生核理论的月球车轨迹跟踪控制*

针对平整坡面上行驶的月球车,研究了基于再生核理论的月球车轨迹跟踪控制新方法.它是基于描述月球车运动的动力学模型方程,对有限时间内的期望轨迹进行采样;利用再生核方法,数值求解控制参数,从而实现月球车期望轨迹的跟踪控制.该方法计算量小、方法简单、精度高,且可实现任意的非线性曲线的期望轨迹追踪.数值实验验证了该方法的正确性和有效性.     

基于微生物菌种资源库的图像智能检索系统研究*

在建设微生物菌种资源平台的基础上, 设计开发微生物菌种资源数据库管理系统,实现基于内容的Web图像智能检索系统.该检索系统采用B/S体系架构,可根据微生物菌种文本信息或图像的形状、纹理和颜色特征进行检索,有效提高了微生物菌种图像信息搜索的查准率、查全率和查找速度.     

Coordinated Recovery of Middleware Services:A Framework and Experiments

Being the most popular runtime infrastructure for distributed systems, middleware can be viewed as a collection of common services. Since the development, deployment and maintenance of distributed systems rely largely on middleware services, the failure of middleware services puts a significant impact on the reliability and availability of the whole system. Though recovery-based fault tolerance is an effective way to improve the reliability of middleware services, it is far away from practice mainly because of the high complexity and cost of the recovery of correlated failures between interdependent services. In this paper,a framework for detecting and recovering the correlated failures of middleware services in an automated way is presented. First, the problem is investigated from two perspectives, i.e.,analyzing the role and impact of middleware services and illustrating a set of correlated failures in J2EE standard services as motivating examples. Then, a general coordinated recovery model is constructed with the elements necessary and su±cient for detecting and recovering correlated failures in middleware services. The supporting framework is demonstrated on three J2EE application servers, i.e., PKUAS, JBoss and JOnAS, one by one without fundamental modifications. Finally, based on the three enhanced application servers, many cases on J2EE common services, including the transaction service, database service, naming and directory service, security service and messaging service, are studied. The experiment results show the effectiveness and applicability of the framework presented in this paper.     

人脸识别研究综述*

人脸识别是一种重要的身份鉴别技术,具有广泛的应用前景。给出了人脸识别发展历程中的技术特点;根据人脸检测定位、面部特征提取和人脸确认识别三个关键的人脸识别过程,阐述了目前已成熟的核心技术和方法以及这些技术和方法的优缺点;展望了人脸识别未来的研究趋势。     

Challenges and recent progress in thermal management with heat pipes for lithium-ion power batteries in electric vehicles

Electric vehicles(EVs) are globally undergoing rapid developments, and have great potentials to replace the traditional vehicles based on fossil fuels. Power-type lithium-ion batteries(LIBs) have been widely used for EVs, owing to high power densities,good charge/discharge stability, and long cycle life. The driving ranges and acceleration performances are gaining increasing concerns from customers, which depend highly on the power level of LIBs. With the increase in power outputs, rising heat generation significantly affects the battery performances, and in particular operation safety. Meanwhile, the cold-start performance is still an intractable problem under extreme conditions. These challenges put forward higher requirements for a dedicated battery thermal management system(BTMS). Compared to traditional BTMSs in EVs, the heat pipe-based BTMS has great application prospects owing to its compact structure, flexibility, low cost, and especially high thermal conductivity. Encompassing this topic, this review first introduces heat generation phenomena and temperature characteristics of LIBs. Multiple abuse conditions and thermal runaway issues are described afterward. Typical cooling and preheating methods for designing a BTMS are also discussed. More emphasis on this review is put on the use of various heat pipes for BTMSs to enhance the thermal performances of LIBs. For lack of wide application in actual EVs, more efforts should be made to extend the use of heat pipes for constructing an energy-efficient, cost-effective, and reliable BTMS to improve the performances and safety of EVs.