防空导弹垂直发射技术的现状及趋势

本文介绍了防空导弹发射技术的现状,垂直发射技术的特点、发射方式和关键技术,国外采用垂直发射技术的几种防空导弹型号以及垂直发射技术的发展趋势。     

产品垂直差异、产品内分工与南北贸易

存在产品垂直差异和产品内分工的贸易模型可以更为深刻地考察南北贸易的模式及影响因素。其中,生产技术仍然是决定生产分工格局的重要决定因素,当其他条件保持不变时,如果南方生产技术水平提高,其将扩大生产范围,在保持生产原有质量产品的情况下,向更高质量产品的生产领域进军。而北方发生技术进步时,其生产范围将缩小,抛弃低质量产品的生产,专攻高质量产品的生产。当两国分别在不同的生产阶段发生技术进步时,基本变化趋势是使本国发生技术进步的生产阶段趋向高质量产品的生产。     

Corporate Venture Capital and Its Contribution to Intermediate Goods Firms in South Korea*

Set by government, corporate, financial and individual sources, venture capitalists in Korea have adapted themselves to the new and uncertain venture capital market through stand‐alone and syndicated investments. The present study raises questions about whether various financial sources contributed differentially to their portfolio firms during the market boom of 2000. Results show that no single capital source showed better performance, and only corporate venture capitalists contributed to intermediate goods firms. The latter finding might reflect the unique ability of corporate venture capitalists to use vertical value‐chain linkages for their investments.     

百万等级机组塔式锅炉螺旋水冷壁安装工艺研究

上海外高桥第三发电厂2×1000MW机组工程拥有二台超超临界的塔式锅炉,针对其螺旋水冷壁的安装特点,设计制造了一副炉膛内垂直升降吊架满足安装需要。本文总结和论述该吊架在1000MW机组锅炉安装中的设计与应用。     

Progression,Stability, or Decline? Sociological Mechanisms Underlying Change in Specialization Among Birdwatchers

Using a panel of American birdwatchers collected in 1997 and 2002, we tested the extent to which birdwatchers progressed over a five-year period. The impact different career contingencies and life course events had on predicting change in birdwatchers' behavior, skill, and commitment was also examined. Findings indicated that although progression characterized some birdwatchers' participation, involvement by others was better characterized by stability or decline, which was true for each of the indicators used to measure specialization. Career contingencies and life course changes had only a moderate influence on predicting change in the specialization indicators over time. Support from family members and retirement were the best predictors of change in specialization.     

民营企业的经营抉择:专业化或多元化

民营企业是专业化发展还是多元化经营,一直困扰着民营企业家。文章认为,目前中国的民营企业正在分化为两大趋势:一部分企业坚守岗位,深化自己产业的深度、纵度、精细化;另一部分企业则开始朝着多元化趋势发展。应根据企业规模、企业在本产业的发展潜力等具体情况,决定发展模式。     

在远程教育下提升教师专业化知识中的价值研究

教师专业化成为教师自身发展的必然要求,已成为世界各国教育者研究的趋势和潮流。通过研究教师专业化的开放性、阶段性、动态性、实践性等特征,分析了远程教育教师应具备素养性知识、条件性知识、行为性知识、实践性知识等知识类别。     

Product Differentiation in the Spanish Beef Industry

Abstract

This paper aims to investigate changes in the structure of the Spanish quality beef industry in response to the significant decline in beef consumption happened over the last few decades. The role of product differentiation, mechanisms and factors involved in it, are specially studied. We use focus groups and a survey to examine the outlook for the organization of the beef industry, and trends in the development of product differentiation mechanisms and vertical co-ordination strategies.

Results reveal the existence of a restructuring process that is being implemented in two ways: Protected Geographical Indications (PGI) and Quality Certified Brands (QCB). Each strategy forms its own entry barriers: the origin of calves in the case of PGI and farm size in QCB; they are therefore complementary rather than competitive.     

铰链门垂直刚度探析

铰链门的设计要素及评价指标较多,其中最重要的要素是垂直刚度指标。垂直刚度指标的确立及研究对车门设计具有指导意义。文章重点阐述了垂直刚度的分析方法及指标。     

立板补焊试件的焊接工艺

根据第三届全国职工职业技能大赛立板补焊项目的培训经验,介绍此项目的操作方法及具体工艺措施。焊后经检测,焊缝外观成形及无损探伤均满足相关标准要求。