管理科学面临复杂性科学的挑战

复杂性科学作为21世纪的科学令世人瞩目,受各界垂青。管理科学面临着复杂性科学的挑战。文章首先介绍复杂性科学的基本思想,其次论述复杂性科学的研究思路与方法,然后分析电力系统管理的复杂性和管理科学面临着复杂性科学的挑战。     

关于电阻测量几种方法的讨论

本文对电阻的测量方法及误差修正进行了比较和分析，并给出合理、直观、简捷的实验测试手段。     

长直螺线管中的交变磁场

长直螺线管中变化的磁场是产生涡旋电场的源，涡旋电场也将反作用于磁场．在一般情况下，磁场的分布不是均匀的。文中指出了一般教材中假定磁场均匀分布的条件，推导出了一般情况下的磁场分布曲线，并进一步讨论了交变电磁场用频率及导休时磁场分布的影响。     

Managing Potential Health Risks from Electric Powerlines: A Decision Analysis Caught in Controversy

Over the past 20 years, several epidemiological studies have found an association between exposure to electromagnetic fields (EMFs) and health effects, including childhood leukemia and adult brain cancer. However, experts strongly disagree about whether this association is causal and, if so, how strong it is. In this article, we examine several alternatives to reduce EMFs from sources of the California power grid, including undergrounding distribution and transmission lines and reconfiguring or rephasing lines. The alternatives were evaluated in terms of the potential health risk reduction, cost, impacts on service reliability, property values, and many other consequences. Because of the uncertainty about an EMF-health link, the main effort was to determine the sensitivity of the decisions to the probability and seriousness of an EMF hazard. User-friendly computer models were developed to allow stakeholders to change the model assumptions and parameters to analyze the impacts of their own assumptions and estimates on the decision. The analysis clearly demonstrated that only four of the many concerns raised by the stakeholders could make a difference in the decision: health risks, costs, service reliability, and property values. Whether undergrounding, moderate alternatives for EMF reduction, or no change was the best decision depended on a few key factors, including the probability that EMF exposure is a hazard, the severity of this hazard, how the EMF reduction measures are financed, and the impacts on property values. While the analysis did not resolve the EMF issues, it showed that even in the most controversial settings, a little analysis goes a long way to clarifying the issues and to focus the debate.     

工程工作站在卡车耐撞性分析中的应用

简要论述了汽车耐撞性解析的基本方程及计算方法。以一轻型卡车为例,结合计算方法讨论了工程工作站(Engineering Workstation)在卡车耐撞性解析中应用的几个问题。介绍了一种适合于工程工作站的接触面设定方法。最后给出了一个数值模拟结果。     

略论西方国家电力监管立法及其借鉴意义

在系统介绍西方国家电力监管立法的基础上,就西方国家在电力监管立法的基本意义、价值目标和基本模式、内容等进行了全面分析,从中总结出了电力监管立法要注意制定监管规则、保持监管之独立性,以及支持竞争保持中立等对我国具有重要借鉴意义的若干经验。     

偏振光的双光束与多光束干涉

本文通过时平面偏振光的双光束与多先束干涉现象的讨论，使对偏振光的干涉有进一步的认识，并计算出偏振光照明条件下，光栅的光强分布和分辨本领。     

相对论的建立与高层理论观念的能动作用

本文首先简述了相对论的理论构建过程，然后扼要地说明了在其理论构建过程中所涉及利的高层理论观念，最后探讨了高层理论观念在现代物理研究中的能动作用．     

几种传输线的场分布

求开放平板线、外正三角形內圆同轴线、外方內圆同轴线、外正六边形內圆同轴线的特性阻抗而建立的精确保角变换的基础上,本文进一步讨论了显式逆变换函数,从而求得了这几种传输线的场分布的闭合表达式。由于所用保角变换的精确性,所得的显式场分布在内导体和外导体的内接圆尺寸之比小于0.5in。基本上是准确的,在这个尺寸比稍大些时也可作为参考。这些场分布对于了解传输线的功率容量,计算衰减常数,考虑功率耦合,设计有关的有源器件等都是必不可少的。文中获得的几种传输线的场分布的显著特点是计算方便,在一般实用范围內有足够的精度。     

新型高压静电解冻柜设计

针对肉食品专营店和餐饮店对冷冻肉的解冻需求,设计研制了一台新型高压静电解冻柜。该解冻柜采用了高压静电解冻技术。设计了基于可编程逻辑控制器( PLC)的控制系统,可自动调控解冻柜温湿度和电场强度。根据设计性能参数,计算了解冻过程所需加热、制冷负荷和加湿蒸汽量。经解冻实验表明,该解冻柜能缩短解冻时间,降低汁液流失率,抑制微生物的繁殖,且解冻后肉样外观新鲜,肉色泽鲜红,具有实际应用价值。