变电设备接头发热处理与分析

变电设备接头发热一直是影响电力系统安全稳定的一个重要因素。文章从近年来苏州供电公司辖区内变电设备接头发热故障的原因统计,得出接触电阻过大是造成变电设备接头发热的最直接的原因,通过对接触电阻的解析得出增加接头的有效接触面为减小接触电阻的方法之一,由增加接触面的方法得到了发热故障接触面处理的标准工艺流程,最后通过一起COMPASS中异型接头发热的故障处理案例来论证了增加接头接触面对于发热处理的有效性。     

动静触头闭合状态下的接触电阻故障及其处理

动静触头在闭合状态下工作时,不如同样材料和几何尺寸的整块金属导电性能好。因此在接触面上必存在一定的接触电阻,它由收缩电阻和表面膜电阻组成。接点(动静触头)在闭合状态下接触电阻可能产生故障,并应采取相应的对策,现举例说明。1332MD槽筒机,通过机械凸轮式间歇触点,使两台主电机同时产生断续运行来满足工艺要求。但该接点多次发生触点熔化故障,其原因是由于接触不良使接触电阻变大发热,造成接触点温度高于材料的熔点,致使接点上银焊剥落,引     

电连接器常用接触件设计中的关键点

电连接器常用接触件的加工设计中,对可靠的接触性有着较高的要求,分析刚性插件、悬臂式插孔、线簧式插孔、冠簧式插孔、爪簧式插孔的结构形式,及其应用在连接器中的设计要点。     

电梯电气线路接触不良的故障排除

电梯电气线路的导线间、触点间、导线和电气装置等连接处,均存在接触电阻.正常情况下,接触电阻阻值一般是mQ级,不会发生线路故障.环境温、湿度,接触表面清洁度、氧化程度,接触面积、压力等因素恶化会引起接触电阻阻值升高,线路会出现所谓的"接触不良",导致电梯故障.     

纳米改性塑料的应用分析

从上个世纪90年代初开始，就有运用将尼龙12与碳纳米管做成内部阻隔层，应用在汽车燃油管组件例如快速连接器和过滤器中。Hyperion Catalysis现在则瞄准于将纳米管引入到别的树脂材料中应用到汽车的燃料系统中。比如改性尼龙和一些含氟聚合物。这种新型含氟聚合物／纳米管复合材料可以用来制造车用燃油连接器的O形圈。     

水下连接器振动测试技术研究

水下连接器振动测试技术采用液压振动测试技术,对水下连接器振动测试装置进行总体方案设计,主要包括机械结构方案设计、液压系统方案设计、控制系统方案设计3部分。论述了水下连接器振动测试装置技术的基本工作原理,并对三个部分进行方案设计。针对液压伺服系统进行了技术研究,包括液压伺服系统的基本原理、负载分析、控制系统回路。采用AMESim仿真软件对液压控制系统进行动态仿真分析,搭建了水下连接器振动测试技术液压系统仿真模型,对液压系统子模型选取及参数设定,得出了位移和速度曲线,并分析了曲线部分失真的原因。     

汽车工业的可靠性技术

随着汽车工业不断进步和社会工业化程度进一步发展 ,现在的汽车无论从结构、性能较之过去都有了很大的改进。表现在结构日趋复杂、做工愈加精细、质量更加可靠、自动化程度更高。特别是在石油行业等能源采掘行业 ,由于特殊的地理条件限制 ,一些工程施工车辆 ,对整车质量可靠性的要求更高。如何运用现代质量可靠性理论 ,开发新兴的可靠性产品 ,并运用在这些施工车辆上 ,是石油工程车辆发展的一个趋势。因为汽车质量可靠性比起汽车的其它性能更显得重要 ,可靠性是基础、是其它性能的载体。汽车可靠性是汽车设计、制造质量和使用维修中的重要指…     

导电膏在电气连接中的应用

分析了电气接触电阻的形式机理及其危害，使用导电膏是降低电气接触电阻的较为有效途径，通过实例说明导电膏在电气连接中的应用效果。     

一种多通道直流中间继电器自动校验仪的开发及应用

开发一种多通道的直流中间继电器自动校验仪,解决直流继电器手动校验过程中的一系列技术问题。可以自动测量出中间继电器线圈得电的动作电压,失电的释放电压,线圈电阻、NC常闭触点接触电阻、NO常开触点闭合后的接触电阻,并能通过与设定的报警阈值比较,自动判断待测继电器是否合格,同时支持数据在线显示和导出。     

国内外汽车电子设备外界环境条件试验发展状况

汽车电子技术已经迅速成为汽车行业发展极快的前沿技术领域,因此汽车电子设备的可靠性研究变得越来越重要,温度、湿度、盐雾、振动等外界环境条件是影响电子设备性能和可靠性的重要因素。介绍了国内外汽车电子设备外界环境条件试验的发展状况,并为促进国内汽车电子设备外界环境试验发展提出了相应的对策。     

雇员接触点管理研究

从雇员进入企业后接触到的企业对雇员的各个"影响点"的分析入手,提出了雇员接触点的概念,揭示了影响雇员工作动力和工作绩效的因素,构建了雇员接触点模型,从与雇员经济收益相关性、工作相关性、雇员发展相关性3个方面对雇员接触点进行了分析,最后提出雇员接触点管理策略和方法。     

外压作用对特殊螺纹接头内压密封性影响分析

对带金属密封结构的特殊螺纹接头来说,保证接头的密封可靠性是很重要的。根据井下管柱实际载荷工况,应用有限元方法研究了拉伸与内压载荷作用下的特殊螺纹接头同时受外压载荷时接触压力的变化,分析了此种工况下特殊螺纹接头的密封可靠性。分析结果表明,外压作用降低了特殊螺纹接头密封面接触压力。如果内、外螺纹的锥度、密封直径与螺纹中径的配合处于较差条件时,外压作用将导致特殊螺纹接头密封面上接触压力消失,使得密封面失去密封能力。研究结果表明,在评价特殊螺纹接头设计及工况适用性时,应考虑进行拉伸加内压加外压的复合载荷试验,增加评价结果的可靠性。     

The risk of contagion from multimarket contact

It is conventional wisdom that the strategic linkage of markets that is enabled by multimarket contact typically increases the profitability of cooperation among rivals. We find to the contrary that a strong force against strategic linkage results from imperfect monitoring of adherence to cooperation. With such imperfections, strategically linking markets can lower payoffs by permitting the impact of adverse shocks in one market to spread to others. Consequently, players of repeated games on more than one front may find it strictly advantageous to avoid linking strategies on a front with clear monitoring to outcomes on a front with error-prone monitoring. One implication is that antitrust, competitive strategy, and foreign policy analyses have presumed too broadly that multimarket contact fosters cooperation. The game-theoretic equilibria characterized here shed light on why players such as firms and nations sometimes strategically link fronts in their rivalry, and sometimes take care to articulate that some fronts of particularly volatile conflicting interests will not trigger broader adverse moves against the rival.     

Heredity or Environment: Why is Automobile Longevity Increasing?

Over the past 25 years the longevity of automobiles has increased dramatically. We disentangle the rise in longevity into an embodied or inherent-durability effect and a disembodied effect (driven by the external environment, such as reduced accident rates or reductions in the prices of auto repair parts) and estimate these effects by year from 1950 through 1991. We find that the entire rise in auto longevity is due to some force disembodied from the cars themselves and offer some speculation about the nature of this external environment.     

The Impact of Urban Development on Auto Ownership and Transit Use

This study documents an investigation of how intermetropolitan differences in transit and highway service levels; as well as overall urban development patterns, affect auto ownership and use. Specifically, this paper presents models of the determinants of auto ownership and mode choice for 163,488 white, single-worker households residing in the largest 125 SMSAs in 1970. Indices of highway capicity, transit service levels, and overall residential density for each SMSA together with each household's socio-economic characteristics, workplace location, and residence choice, are used to explain each household's observed auto ownership status (0, one, or more than one car), and, given that auto ownership status, each household's worktrip mode (auto driver, auto passenger, bus, rail, or walk).
The models offer a framework for considering the effect of alternative urban development scenarios upon auto ownership and use, and for comparing alternative development and infrastructure policy options. Because the models have been estimated using households from different SMSAs, they are particularly appropriate for investigating changes in spatial structure.     

The Harvesting of USAUTO?

A great many explanations have been offered for the precipitous decline of Detroit as the dominant force in the North American automobile market. One of the key factors not yet explored in-depth is the competition for differential marketing advantage between domestic and foreign auto companies. This competition is documented with comprehensive new evidence covering the free-market years between the first oil embargo and voluntary import restraints. A controversial relationship between differential advantages and change in market share is tested empirically and found to hold. The implications of competitive marketing parity are discussed and the authors conclude that domestic auto companies may have had no choice but to harvest their market position.     

由“日本大地震”引发的中国工程可靠性及其管理问题的思考

从日本大地震引出工程可靠性的话题,阐释了可靠性工程、可靠性技术和可靠性管理的涵义及其相互关系;通过具体真实的案例介绍了中国现阶段工程可靠性方面的问题现状,并针对案例进行总体的分析和讨论,指出中国现阶段工程可靠性问题产生的主要原因在于:全民的可靠性意识不强、工程可靠性管理体制不健全、可靠性管理资金不落实、工程可靠性管理理论研究滞后等;强调在中国现阶段,可靠性管理比可靠性技术更加需要引起重视,加强可靠性管理有可能会产生出超预期的效果。     

Multimarket Contact in Banking

According to linked oligopoly theory, the anticipated effect of multimarket contact is reduced competition. Specifically, the theory predicts that contact lowers competition by reducing the benefit of aggressive action in any single market by providing rivals with the opportunity to retaliate in multiple common markets. The results of this paper are consistent with the theory. In banking, contact is positively related to profitability. Although the economic impact of this relationship is unimportant for most institutions, the relationship is meaningful for the small group of banks most heavily exposed to contact. This finding suggests that the importance of contact may rise as consolidation of the banking industry continues.     

On the relation between multimarket contact and service quality: Mutual forbearance or network coordination?

Research summary : We reconsider the relationship between multimarket contact and product quality in the airline industry by arguing that multimarket contact has both a negative mutual forbearance effect on quality and a positive network coordination effect on quality. Multimarket contact increases the frequency of contact between firms, and this anticipated future interaction promotes cooperation. In network industries, especially small firms may want to cooperate in order to increase the attractiveness of the composite product. By using size as a moderating variable, we indeed find a consistent positive effect of multimarket contact on product quality for small airlines. We show that this effect can be attributed to network coordination and that this effect generally dominates the negative mutual forbearance effect in a recent period. Managerial summary : Firms with sales in multiple geographical markets likely encounter each other with mutual respect (i.e., live and let live) because aggressive behavior in one market may lead to retaliatory responses in other markets. Such responses weaken competitive pressures on price and quality. Insofar these firms sell complementary products, they may however also coordinate and improve their joint product offering, resulting in better quality for the consumer. This paper shows that this positive effect of cooperation may dominate the negative competition‐reducing effect, depending on the size distribution of firms. The reason is that small or nondominant firms have a stronger incentive to produce compatible products than large or dominant firms with already a strong position in the (global) market. Copyright © 2015 John Wiley & Sons, Ltd.     

The Effect of Bid Rigging on Prices: A Study of the Highway Construction Industry

This paper examines the effect of multimarket contact in afirst price sealed bid government procurement auction market. It investigates whether bidprices in the highway construction industry are related to conditions that favor the formation of a cartel.Repeated contacts among firms are found to have a significantly positive effect on the winning low bidwhich leads to higher profit. Further, rivalry among few firms tends to exacerbate the multimarket effect.The results in this study additionally support the recent theoretical predictions that collusion isbetter sustainable during economic downturns.