AC/DC电路故障检测仪设计

本文介绍了一种可在被检测设备电路不带电状态下工作的AC/DC电路故障检测仪,并对其电路工作原理、测试方法进行了较详细的分析.     

Ethical dilemmas in evaluating programs with family court related clients

Two ethical dilemmas are discussed; breaching client confidentiality in order to intervene in the client's illegal behavior, and defining the role of evaluator as expert witness. The evaluation context concerns a combined program development and evaluation project with clients involved in family court proceedings for child abuse or neglect. Different perspectives, approaches, and experiences in resolving each dilemma are reviewed. The conclusion argues that approaches to ethical dilemmas in evaluation projects must go beyond techniques to disguise data, to include an assessment of the values and value commitments connected to the different roles an evaluator must perform.     

International cooperation in stockpiles and tariffs for coping with oil supply disruptions

This paper provides a unified treatment of oil stockpiling and demand restraint as policy responses for enhancing energy security and examines the implications of recent changes in the structure and performance of the international oil market for the design of policies. These issues are addressed using a dynamic programming framework in which international policy actions of key oil-importing countries are modeled as a Nash dynamic game. Significant policy implications from the analysis include: (1) the result that, with realistic assumptions about disruption risks and inventory capacities, differences between noncooperative and coordinated stockpile policies appear to be minor and (2) significant mutual gains could be reaped from a modest degree of collective restraint on normal market oil demand. The broader role of international cooperation in enhancing energy security is also discussed.     

Commodity prices and the world distribution of income

Some advocates of a new international economic order recommend raising prices of commodities exported by developing countries as a means of reducing the inequality of world income distribution. A simulation model using commodity trade data and income distribution data for 68 industrial and developing countries examines this policy alternative. Initial data compilation reveals that internal inequality is as important as international: The world income share of the poorest 40% of people would be twice as high in the absence of intracountry inequality. Calculations using actual price experience in the “great inflation” of 1972–1975 show that despite the large relative price changes for some commodities (especially oil), these changes left the world size distribution of income virtually unchanged. Separate policy simulations show that even a quadrupling of the price of ali “equalizing” commodities (those mainly exported by LDCs) would leave the size distribution of world income practically unaltered (even under optimistic assumptions about intracountry distributional incidence), although some individual LDCs would gain. Increasing commodity prices therefore appears to be an ineffective means of increasing international equity, quite apart from questions about the feasibility of cartels or commodity agreements.     

单片DC/DC变换器的分析与设计

在0.35μm硅衬底CMOS工艺条件下,分析了集成平面电感器的单片DC/DC变换器的功率损耗,折中考虑了设计中的难点以及各种影响因素。优化了变换器的转换效率,确定其开关频率为100MHz;考虑片上集成平面电感器的单位面积电感值与品质因数的大小也是决定DC/DC变换器性能的关键因素,该文给出了双层平面螺旋电感器的物理设计与几何参数优化,获得了双层平面螺旋电感。模拟结果表明该变换器工作稳定,转换效率可以达到62%。     

高频开关电源技术在电信电源系统中的应用

介绍了高频开关电源技术在电信电源系统中的具体应用,结合具体框图对高频开关整流器模块及通信用二次电源模块的组成及功能作了叙述,并从功率器件、开关技术、工作频率、功率因数校正、同步整流、负载均流等诸多方面阐明了开关电源技术在电信电源系统中的应用。     

Three models of OPEC leadership and policy in the aftermath of Iran

Collapse of the Shah's regime has transformed Iran's attitude regarding oil production policy. The nature of OPEC leadership is changing as well. Three models examine the nature of this leadership inside OPEC: (1) the conventional price leadership model, (2) a model emphasizing a concept of egalitarian leadership, and (3) a team model composed of coalitions. The three models establish the limits within which OPEC leadership is exercised. A composite model drawing upon all three sets of results suggests that Saudi Arabia shapes cartel policy not by itself, but through a dominant coalition of states. For most of the period 1969–1978 this coalition has been stable. Following the unsettling changes of 1973, cooptation of Iran into the dominant coalition in 1974 was an important step in achieving a new level of stability. But during the turbulence of regime transformation in Iran, the nature of the governing coalition appears to have changed. One consequence may be that in the future Saudi Arabia will yield more willingly to arguments heard within OPEC on behalf of upwards price pressure, especially in an atmosphere of growing political isolation and overall tight supply.     

Resolving conflicting demands on evaluation: A test demonstration of videotex for farmers

Evaluating an innovation for federal, state, and local policymakers and program managers alike entails conflicting demands on the evaluation study. Policymakers at federal, state, and local levels are best assisted by impact evaluations, whereas state and local program managers are best assisted by process evaluations. In-house evaluators often have an advantage in conducting process evaluations; external evaluators generally have an advantage in conducting impact evaluations. A cost-effective approach may be to combine in-house process evaluation and external impact evaluation. This dual approach was found to reduce conflicting demands on the evaluation of an experimental videotex system for agricultural producers.     

DC元数据在中国数字图书馆建设中的应用之我见

最新版本的DCMI元数据术语规定了元数据元素、元素限定词和编码体系修饰词定义的必备属性和有则必备属性。本文区分了DC元数据标准中关于修饰词的几个概念,介绍了DCMI元数据术语定义规范和DC元数据在数字图书馆建设中的优势,探讨了本地应用纲要制定中应注意的问题。