高墩大跨连续梁铁路桥动力试验

为检验桥跨结构的实际动力性能，对主跨100m，墩高99m的松头江连续梁铁路桥进行了全桥动力试验，测试其自振特性以及列车以不同速度通过桥跨和在桥上制动时桥跨结构的动力响应，将实测结果与车桥耦合振动分析结果进行了比较，二者基本相符．结果表明，该桥具有良好的竖向刚度、横向刚度和结构强度；列车在桥上运行时对桥跨结构有一定的冲击作用，而列车行车具有良好的安全性与舒适度。     

STUDY ON NATURAL LANGUAGE INTERFACE OF NETWORK FAULT DIAGNOSIS EXPERT SYSTEM

Since Internet was born,the computer net workhas developed at a highspeedinits structure and ap-plication.Facing the huge and complex computernet work,we think it hard to deal with the variousfaults of the net work with manual method.Alongwiththe development of AI,the latest achievementof expert system(ES)has provided a new way forthe fault diagnosis and analysis of net work.Butthese ES don't provide a good interface for user.The interface of ES al ways uses command,menuand windows at pres…     

地铁车站暗挖风道的优化配置

通过对风道的布置形式、土建施工、工程投资的定性分析和使用功能等方面进行多种方案的比较,阐述浅埋暗挖地铁车站中风道的最适合布置形式,以及在不同的条件下应采用的风道设计形式。     

"市民社会"理论的历史流变及其现代意义

“市民社会”理论是近代西方政治哲学中的重要理论。这一理论的发展经历了一个历史的流变过程。市民社会理论尤其是马克思的市民社会理论，对于社会主义市场经济条件下中国市民社会的建立，以及我国市场经济的发展有着重要的理论和现实意义。     

玉京山隧道中厚煤层瓦斯抽放技术

成贵高铁玉京山隧道进口工区C5煤层为瓦斯突出煤层,为保证隧道施工安全,避免发生瓦斯事故,确定采用穿层网格预抽法进行消突。通过方案比选,确定在平行导坑轮廓线左侧设置钻场,平行导坑与正洞整体一次抽放,并确定瓦斯抽放控制范围、开孔间距及终孔间距。防突流程分为区域防突、局部防突和石门防突3个过程,利用瓦斯解吸指标K1值和瓦斯含量来验证消突效果。根据KJ83N安全监控系统对瓦斯体积分数、风速等的实时监测结果可知,采用双风机独头压入式通风可以满足通风要求。玉京山瓦斯突出隧道通过采用系统的瓦斯抽放技术,消突效果显著,为揭煤和穿越煤系地层施工提供了安全保障。     

单缸EGR发动机压缩比优化及涡轮增压器匹配研究

在1台气道喷射单缸EGR发动机上,独立控制EGR缸喷油及点火,实现燃料改质,研究了不同压缩比对发动机性能的影响,此外还匹配了不同涡轮增压器,用于改善外特性扭矩。试验结果表明:单缸EGR能有效改善发动机的燃油经济性,NOx和CO排放性能均所改善,但THC排放恶化,动力性能下降;提高压缩比能有效提高发动机的热效率,降低燃油消耗,但过高压缩比使发动机爆震倾向严重,限制发动机外特性扭矩;通过匹配小涡轮增压器低速扭矩有所改善。     

富水软弱地层中浅埋暗挖隧道施工地表沉降分析——以杭州紫之隧道为例

为深入了解富水软弱地层中浅埋暗挖隧道施工引起的地表沉降特征,以杭州紫之隧道北口浅埋暗挖段工程为依托,采用现场监测数据分析与数值模拟计算相结合的方法,分析地下水渗流作用对地表沉降的影响。分析结果表明:1)在地下水渗流作用下,横向和纵向地表沉降槽宽度系数的拟合值均大于文献中对黏土的建议值;2)在隧道施工过程中,地层孔压下降范围逐渐扩大,地下水渗流是沉降槽宽度增加的主要原因;3)地表沉降主要发生在隧道外侧起拱线处、与水平方向成45°+φ/2的斜线之间区域(φ为隧道上覆土层平均内摩擦角)。     

Probabilistic analysis of the release of liquefied natural gas (LNG) tenders due to freight-train derailments

Liquefied natural gas (LNG) has emerged as a possible alternative fuel for freight railroads in the United States, due to the availability of cheap domestic natural gas and continued pursuit of environmental and energy sustainability. A safety concern regarding the deployment of LNG-powered trains is the risk of breaching the LNG tender car (a special type of hazardous materials car that stores fuel for adjacent locomotives) in a train accident. When a train is derailed, an LNG tender car might be derailed or damaged, causing a release and possible fire. This paper describes the first study that focuses on modeling the probability of an LNG tender car release incident due to a freight train derailment on a mainline. The model accounts for a number of factors such as FRA track class, method of operation, annual traffic density level, train length, the point of derailment, accident speed, the position(s) of the LNG tender(s) in a train, and LNG tender car design. The model can be applied to any specified route or network with LNG-fueled trains. The implementation of the model can be undertaken by the railroad industry to develop proactive risk management solutions when using LNG as an alternative railroad fuel.     

山岭隧道浅埋偏压段综合治理技术浅谈

贵广铁路贺街隧道进口位于浅埋偏压地段,前期施工过程中各种地质灾害屡有发生,并且多次发生大型滑塌、初支侵限、结构大变形现象,对施工进度、安全、质量均产生不同程度影响,为山岭隧道浅埋偏压施工困难之典型。本文系统介绍了如何采取措施确保结构稳定性和综合治理措施以及受力转换合理性,实践证明隧道安全施工得以保证。     

Assessing greenhouse gas emissions from port vessel operations at the Port of Incheon

This paper measures greenhouse gas emissions from port vessel operations by considering the case of Korea’s Port of Incheon. It provides estimates of greenhouse gas emissions based on the type and the movement of a vessel from the moment of its arrival, to its docking, cargo handling, and departure. Taking a bottom-up approach based on individual vessels’ characteristics and using data on vessels processed by the port in 2012 estimate emissions. The results indicate that the level of emissions is five times higher than that estimated through the top-down approach. Among various types of vessels, international car ferries are the heaviest emitters, followed by full container vessels and car carriers. A vessel’s passage through lock gates and maneuver to approach the dock accounts for 96% of its emissions. Docking for cargo handling shows the lowest level of GHG emissions.