废气再循环对增压直喷汽油机热效率的影响

结合热力学第一定律和第二定律深入分析了EGR对增压直喷汽油机在全负荷和中等负荷时热效率的影响机理。全负荷时,EGR的引入可以消除缸内混合气加浓,增加工质比热容比,改善燃烧放热等容度,减少传热损失,从而提高热效率,但其燃烧不可逆损失增加;中等负荷时,EGR的引入除了上述几个因素的改善外,还减少了进排气行程的泵气损失,从而较显著地提高了热效率。尽管EGR使得燃烧过程中产生的不可逆损失增加,但在全负荷和中等负荷时汽油机的有效效率均得到改善。     

《船上油污应急计划》编制及其应用中问题的探讨

船上船污应急计划的编制和实施，对减轻海洋环境污染起了积极作用，尽管目前大量船舶都编制了该计划，经调查发现许多船舶在应用中还存在不少问题，为进一步提高各类船舶对所发生的油污应急反应能力，必须加强演练，定期评估、检查和修改已制定的计划。     

Trip Chain's Activity Type Recognition Based on Support Vector Machine

This paper focuses on support vector machine (SVM) based trip chain's activity type recognition. First, the time-series location information of person trip is processed to obtain the trip chain elements including moving processes and activities, and the activity options are extracted from the geographic information system (GIS) around the activity sites. Second, the activity features are drawn from spatio-temporal factors of trip chain to serve as the input feature vector of classifier. A SVM based one-to-one classifier is established and the method of one-to-one classifier voting is adopted to decide the most likely activity type from the activity options. Finally, the classifiers are trained with simulation data based on the Gaussian radial basis (RBF) kernel function and the multilayer perception (MLP) kernel function respectively, and then examined by cross validation. The result shows that in the one-to-one classifying scheme, the highest and lowest right recognition rate with RBF are 99% and 62%, and the corresponding results with MLP are 97% and 54%, respectively.     

A game-theoretic analysis of competition among container port hubs: the case of Busan and Shanghai 1

Countries throughout the world, and especially within Asia, are investing heavily in container port infrastructure in the hopes of capturing a larger share of global shipping activity for their economies. Many existing ports are emphasizing developing the capacity to serve as a hub port, building deepwater berths with large terminals to facilitate transfer of containers from feeder ships to mother ships for intercontinental transport. We develop a game-theoretic best response framework for understanding how competitor ports will respond to development at a focus port, and whether the focus port will be able to capture or defend market share by building additional capacity. We apply this model to investment and competition currently occurring between the ports of Busan and Shanghai.     

城市轨道交通民营化的发展模式选择

根据城市轨道交通100多年来的发展历程,总结出6种发展模式,并重点研究了其中3种民营化的发展模式.在此基础上,分析了城市轨道交通民营化发展过程中存在的4个主要问题.结合中国的实践,对如何选择城市轨道交通发展模式提出了建议.     

潜艇大气环境多传感器信息融合技术研究

介绍多传感器信息融合技术的概念,分析了多传感器集成与信息融合的问题,介绍了贝叶斯准则、D-S证据理论、模糊理论和神经网络的4种方法与算法,论述了潜艇大气环境多传感器信息融合技术研究的优点及其必要性.     

基于GIS的铁路绿色选线决策支持系统的研究与设计

为了解决铁路建设带来的环境问题，围绕铁路环境保护“十五”计划中提出的“绿色选线”制度，运用系统分析和多目标决策的理论和方法，以地理信息系统（GIS）为主要技术支撑，以决策支持系统（DSS）为核心理论，并引入基于组件的软件开发方法，从铁路线路方案的环境影响问题出发，结合其特点，对基于环保理念的铁路绿色选线决策支持技术进行了研究，完成了基于GIS的铁路绿色选线决策支持系统的总体设计与实现，完善了现有铁路选线过程中环境问题的考虑方式，提高了决策的能力和智能化水平。     

美国GE转向架构架铸造工艺研究

本文叙述了GE构架产品结构特点和技术要求,分析了铸造工艺上的技术难度,以及为控制铸件尺寸,解决铸件变形和解决铸造裂纹等缺陷问题所采取的多项工艺措施和工艺试验.从而保证了新型三轴整体铸钢构架铸造成功。     

铁路建设项目社会评价初探

铁路是我国国民经济的大动脉，项目投资规模大，涉及范围广，对区域经济和社会发展影响显著，涉及环境保护、征地拆迁、移民安置等问题，有明显的外部性和公益性特征，因此，从客观上要求在项目论证中必须重视各种社会因素的分析评价。阐述了社会评价在我国铁路建设项目中的应用情况，重点分析了铁路利用外资项目实施社会评价的主要经验，并对我国铁路项目开展社会评价工作提出建议。