Fertility,human capital and the wealth of families

Summary An overlapping generations model with parental altruism is examined. The existence of the optimal value function in a model with an endogenous discount rate is proven. Two development regimes are produced: a high fertility, low income and no growth steady state, and a perpetual growth equilibrium with low fertility and rising income.This paper is adapted from my dissertation. I would like to thank the members of my dissertation committee for helpful comments and suggestions, Messrs, Gary S. Becker, Robert E. Lucas, Jr., Kevin M. Murphy and Sherwin Rosen. I'd like to thank Brooks Pierce, Paul Romer, Ken Judd, Beth Ingram, Ed Prescott and Fernando Alvarez. I also thank the workshop participants of the University of Chicago, University of Pennsylvania, University of Toronto, University of Rochester, University of Washington, Penn State University, University at Buffalo, SUNY, Columbia University and University of Iowa.     

采用改进遗传算法的变压器优化设计

电力机车变压器的优化设计,采用遗传算法是比较好的选择,但传统遗传算法存在一些弊端,文章从编码方式、遗传操作等几个方面探讨了如何对其进行改进,并使用Visual C++编写了一套设计软件,实践证明这种改进是有效的。     

大型变压器在线监测技术及其发展

该文综述了国内外大型变压器在线监测及故障诊断技术的现状,针对电力变压器结构的复杂性及分布广、少人或无人值班等工作特点,提出了红外温度监测技术及GPRS技术在大型变压器远程在线监测及故障诊断中的应用前景。     

Publishing performance in economics: Spanish rankings (1990–1999)

Abstract. This paper contributes to the growing literature that analyses the Spanish publishing performance in Economics throughout the 1990s. Several bibliometric indicators are used in order to provide Spanish rankings (of both institutions and individual authors) based on Econlit journals. Further, lists of the ten most influential authors and articles over that period, in terms of citations, are reported. We are grateful to many colleagues who made very useful remarks to preliminary versions of this paper, as well as to two anonymous referees. We are particularly indebted to Xavier Sala-i-Martín, without whose invaluable help this work would not have been possible. All errors or omissions are of our exclusive responsibility.     

Entry deterrence and innovation in durable-goods monopoly

This paper investigates the efficiency of innovation investments in a durable-goods monopoly when a potential entrant threatens to innovate as well. We show that the durability of the good endows the monopolist with the power to discourage rival innovation since current sales alter the demand for a new generation of the good. The equilibrium is therefore determined not only by the incentive for intertemporal price discrimination in durable-goods monopoly, but also by the incumbent's concern for maintaining the technological leadership. We demonstrate that entry deterrence followed by no innovation always implies underinvestment in innovation.     

10kV开关设备检修要点分析及应用

在配电系统中,开关设备是非常关键的部分。它若出现故障,可能引发大面积停电事故,会增加运行成本,降低设备的使用功能,而且有损电力公司的社会形象。本文基于现代电力系统运行要求,重点分析了10kV开关设备检修要点,旨在积累更多运行维护的技术经验,在保证设备功能的前提下,降低运行成本,提高电力系统运行的安全性和可靠性。     

继电保护在农村1OkV电网线路的应用

继电保护技术随着电力系统的发展而不断发展,它为电力系统运行提供了安全保障,是提高供电质量、减少事故损失最直接有效的手段.目前我国农村电网发展现状不容乐观,继电保护技术的引入为农村电网发展注入了新的活力.文中主要分析了继电保护技术在农村10kV电网线路中的应用及其应注意的问题等,以促进我国农村电网健康的发展.     

岩滩水电厂3 6万kVA主变压器水冷却方式的控制特点

岩滩水电厂机组单机容量为30.25万kW·h,主变压器为三相三柱式,容量为36万kVA。因受到当时制造工艺、技术要求以及运输路线的限制,致使大容量的主变压器做成体积小巧的三相三柱式,在运行过程中主变压器油温长期处于高温状态下,特别是夏季大负荷时主变压器油温达到65℃以上,对主变压器的安全运行形成潜在安全隐患。岩滩水电厂的主变压器采用水冷却方式后,主变压器油温降低了近20℃,在夏季最大负荷情况下温度基本保持在47℃左右,达到了改造前的预期目的。     

10kV配电网馈线自动化发展与现状分析

文章结合配电自动化的概况,对馈线自动化以及电压型馈线自动化设备的实现进行了分析与介绍,并对10 kV配电网馈线自动化的现状以及改造目的做了阐述。     

10kV配电线路接地故障原因及有效预防措施

配电线路是电网的基础设施,其故障发生频率较高并且涉及的原因也比较广泛。文章主要介绍了10 kV配电线路中单相接地的故障类型及发生原因,并阐述了一定的预防措施和处理方法以及新技术和新设备在该方面的应用。