S7-200PLC的自由口通信技术在电机控制中的应用

本文介绍了西门子S7-200PLC利用自由口模式通信协议实现电机控制的两个实例,阐述了自由口通信模式实现电机控制的关键技术和注意事项,系统地研讨了PLC的自由口通信技术在电机控制中的应用。     

基于子模型的车身结构分析与优化

在车身有限元分析中,由于局部结构的尺寸较小,在整车的网格模型下局部无法获得足够精度的计算值,整车车身模型细化网格会显著增加计算时间。解决此问题的方法有子模型技术和子结构技术,其中子模型技术具有明显的优越性。文章将子模型技术应用至某微车强度的计算。获取子模型边界条件,对该子模型进行网格细化处理后再求解。比较计算可得,通过运用子模型技术,在保证仿真精度的基础上提高了计算效率。文章选取实际耐久性试验车的焊点开裂案例,进行基于子模型方法的优化分析,优化时间显著减少,优化后应力值明显减小,解决了开裂问题。     

The Production Boundary Reconsidered

Hill and Hawrylyshyn rediscovered a classical contribution made by Margaret Reid as early as 1934, known now as the “third party criterion.” The general production boundary in SNA 1993 is defined by using this criterion. They considered that the property of “delegability” was the key to the concept of economic production. That is, an activity is called production in an economic sense if it can be delegated to another economic unit. The author calls due attention to the fact that the SNA includes another criterion, which he tentatively calls “World 1 criterion” meaning that an activity is called economic production only when it is a physical process, where the term World 1 is due to Karl Popper. It is claimed that this criterion can generate a more appropriate general production boundary for the SNA if it is used with “role‐exchangeability” criterion, another new criterion.     

The Effects of Cultural Distance,Free Trade Agreements,and Protectionism on Perceived Export Barriers

ABSTRACT

This article addresses the questions as to whether cultural distance and a free trade agreement with a trade bloc, as well as protectionism, have an impact on perceived external export barriers. The evaluation of a mail survey of chief executive officers from 459 Norwegian companies shows that protectionism has a strong significant effect on the level of perceived external export barriers. The cultural distance to the export markets has only a small effect, while the free trade agreement with the European Union has no effect.     

一类含有Sobolev-Hardy临界指数的边界奇异椭圆方程正解的存在性

在本文中,我们探讨了一类含有Sobolev-Hardy临界指数的半线性椭圆方程正解的存在性,该问题具有边界奇异性(0∈Ω)。利用变分法和极大值原理证明了该问题正解的存在性,推广了已有的结果。     

手机电视业务的免费商业模式设计

研究了免费经济的规律及已有的商业模式成果,对免费商业模式进行系统分析。结合我国手机电视发展的特点,从运营模式、产业链、盈利模式等角度,设计了适合我国手机电视发展的免费商业模式,主要包括通过基础平台的免费共享扩大用户数量以及广告、增值服务、交叉补贴等途径增加利润,从而达到产业链各环节利益最大化的目标。     

科学发展观引领下的免费师范生学习主动性培养

本文分析了免费师范生学习主动性不强的现状及原因,探索作为辅导员如何以科学发展观为指导,创新工作方法,从增强免费师范生教师意识、提高免费师范生实践能力、做好免费师范生的心理健康教育、培养免费师范生感恩意识等工作着手,努力提高免费师范生的整体素质,增强免费师范生学习的主动性。     

中国当前区域一体化协议的发展特点与应对策略

中国RIAs中涉及FDI条款的主要特点是中国目前的（区域一体化协议）RIAs伙伴国和接洽国在中国的贸易总量中仅占较小的比例、亚洲或亚太地区是区域经济合作重点区域、南南型RIAs是合作的主流、RIAs战略中政治因素高于经济因素。应积极开展RIAs谈判,避免被区域一体化组织边缘化;利用RIAs平台实现我国企业的＂走出去战略＂;利用我国巨大的市场规模的优势,在RIAs谈判中争取战略主动。并注意在合适的时机有选择的开展与发达国家的区域一体化谈判、加强与西亚地区的区域经济合作、在RIAs协议中应该重点体现针对服务业投资自由化的内容等。     

Buyers’ perceptions of importance and willingness‐to‐pay for certain attributes of source and production verified bred heifers

This research reports buyers’ perceptions of and willingness‐to‐pay for replacement heifers produced through a rigorous, third‐party verified production protocol. Survey respondents attended and registered to purchase heifers at sanctioned Missouri Show‐Me‐Select Replacement Heifer Program^® sales between 1997 and 2002. Responses indicate that pen uniformity, artificially inseminated to calving ease bull, synchronized calving, and heifer size are perceived as important, and their willingness‐to‐pay for these characteristics is economically significant. Though prior research suggests willingness‐to‐pay estimates particularly for inexperienced consumers may be biased, we find little difference between inexperienced and experienced buyers and also little difference from hedonic estimates of heifer characteristics’ value.     

Islamic Banking in Malaysia: Unchartered Waters

This paper explores the Islamic banking business in Malaysia since its beginning in 1983. The Islamic banking sector has achieved its target of 20% market share in assets and deposits in 2010. To boost the industry's competitiveness and efficiency, the demands of the market forces will have to be delicately balanced with the dictates of the Shari'ah. The search for niche Islamic banking products warrants enhancements in the current regulatory, legal, and fiscal infrastructure for Islamic banking, without which these products cannot be a viable alternative to the conventional ones. While the prevailing infrastructure is conducive to Islamic banking products that hold similar characteristics with interest‐bearing loans, Shari'ah compliance can be a futile exercise when the purpose of the law (maqasid al‐shari'ah) is overlooked, for there is much more to Islamic banking than the elimination of interest.