桥梁预制拼装体外预应力耗损及转向块功效

计算对接缝压实耗损、摩阻耗损和收缩徐变耗损,借助工程有限元ANSYS系统对块式、肋式转向块的功效适用性开展模拟计算分析,揭示预应力耗损和两种转向块结构型式对工程技术实现以及施工中的结构安全性影响,对同类桥梁建设提供技术参考.     

复合牙灌浆孔支顶法在盾构施工过矿山法隧道中的应用

以广州地铁5号线区庄站至杨箕站盾构区间盾构过矿山法隧道施工为例，介绍了自主研发的复合牙灌浆孔支顶法及其在过矿山隧道的成功应用，可为今后类似的城市轨道交通盾构施工提供借鉴和参考。     

复杂地质条件下港口集装箱码头堆场面层结构设计

介绍深圳CCT港区惠州QCT港区集装箱码头堆场面层结构,采用土工格栅代替习惯用的碎石垫层和改进后的水泥稳定砂垫层,简化了施工工艺,提高了工程质量,降低了工程成本.     

利用汽车制动能量提高发动机充量系数的仿真研究

分析了汽车制动能量回收再利用的几种典型方式及现状,研究了利用汽车制动能量提高发动机充量系数,从而提高发动机功率的理论依据,并利用GT-POWER软件进行了模拟分析。分析表明,利用制动能量能有效提高发动机的充量系数。     

微波除冰关键技术及应用前景分析

由冻雨形成的冰层由于与路面粘结强度大，普通除冰除雪机械无法清除，微波除冰技术可以对冰层与路面接触处进行加热，使冰层与路面分离，实现快速除冰。但是微波除冰技术的应用存在微波利用率低，设备复杂等难点。对钛酸钡加入沥青混凝土之后的微波吸收效率进行了试验，得知加入钛酸钡后混凝土对微波的吸收效率有明显提高，并指出微波除冰技术的研究应该注意微波加热设备的灵活利用和将微波除冰技术纳入综合除冰除雪体系。     

Efficiency of urban public transit: A meta analysis

The aim of this paper is twofold. First, to provide a statistical overview of the literature on public transit efficiency performance. Second, to statistically explain the variation in efficiency findings reported in the literature. To this end, first some key concepts of efficiency analysis will be introduced, while next the different frontier methodologies that are used in the literature will be discussed. The empirical part of this paper consists of a statistical summary of the literature as well as meta-regression analyses for different samples of the literature in order to identify key determinants of technical efficiency (TE) of public transit operators. For a broad sample of observations, we found significant and consistent effects of the type of database, region and output measurement method. For the sample of non-parametric studies we found that the type of frontier assumptions also have an impact on the efficiency ratio. Further results show that there is no statistical difference in TE ratios between parametric and non-parametric studies. Finally, we found a positive univariate relationship between the number of inputs in the estimated specification and the efficiency ratio.     

多缸汽油机进气瞬态性能的研究

本文利用所建立的进气模型，对火花点火式发动机的进气特性进行了数值和分析。结果表明所采用的研究方法具的较高的实用价值，文中还对火花点火式发动机的各缸进气不均匀性和不均匀偏和了研究，为改善发动机缸内燃烧过程的均匀性提供了有效的方法。     

The operation of Swedish motor-vehicle inspections: efficiency and some problems concerning regulation

Efficiency in the operation of the Swedish motor-vehicle inspection monopoly was examined by analyzing data on all decision-making units related to production of inspection services during 1993. In addition, theoretically based arguments concerning some regulation problems are discussed. The results imply a fairly high level of technical efficiency, which might be explained by the extensive practice of yardstick-competition in the industry. The findings, based on a best-practice approach, do not indicate strong empirical evidence in support of a deregulation of the industry. However, the regulation problems discussed may provide motives for deregulation.     

Productivity,efficiency and technical change in the European railways: A non-parametric approach

The purpose of this paper is to analyse the evolution of productivity in the European railways in the period 1970–95. We use a non-parametric approach that enables changes in productivity to be broken down into variations in efficiency and technical change. The results indicate that the productivity growth is concentrated in the last period (1985–95), when the majority of the companies undertook processes of reforms. This increase in productivity is mainly due to technical progress. We also analyse the determinants of efficiency and, unlike other papers, the technical change, finding that the greater the degree of autonomy and financial independence, the higher the efficiency levels and technical change. This revised version was published online in June 2006 with corrections to the Cover Date.     

提高阻挡大型机动车辆路障效率的研究

随着当今世界各国对安全的重视和汽车炸弹恐怖袭击的层出不断,防恐机动车阻挡路障的研究和应用成为重要课题。本文主要针对阻挡大型高速货车类车辆的路障进行了试验研究,利用LS-DAYNA建立了和试验结果吻合的有限元模型。参考美国DOS(Department of State)标准关于机动车阻挡路障的要求,通过模拟计算方法研究了如何提高对大型高速车辆的阻挡效率、减少车辆穿过路障距离的方案。模拟和试验表明,所提方案可以有效地阻挡大型车辆,对提高我国相关产品的性能并使之与国际标准接轨有重要指导作用。