外部激励对发动机外平衡影响的道路试验研究

为探求车辆行驶时外部激励对发动机外平衡的影响,结合车辆行驶时发动机工作特点,以发动机横、纵中心截面相对振动位移作为评价指标,以路况、挡位和车速作为考察参数,在2种差异较大的路况上进行了2挡和3挡多车速道路试验.并根据DoE方差分析法对试验结果进行定量分析.分析结果表明,发动机外平衡受车速和路况影响较大,受挡位影响较小;各参数的交互作用对纵向外平衡影响显著,对横向外平衡影响不显著.     

La sous-traitance dans le transport routier de marchandises: les enseignements de l’enquête ECHO (2004)

Road haulage is nowadays the main transport mode in France, demonstrating its ability to fulfil shippers’ demands. Among other success factors, the possibility for large companies to subcontract to very small ones, with very low fixed costs and greater flexibility, is often quoted as a major advantage. The ECHO survey, conducted in France in 2004, gives information about 10000 shipments made by 3000 shippers. This survey allows the analysis of subcontracting, by following at every stage how each shipment is given to another carrier by contract. The analysis shows that some subcontracts are mainly cost driven, but others aim at using the specialised skills of a particular haulier. For every transport segment (single parcel delivery service, parcel delivery service, less than truck load, full truck load), subcontracting is described in terms of sizes of the companies involved, services provided and the reasons for subcontracting. These results describe the main features of several different types of subcontracts.     

Path Tracking for Autonomous Race Car Based on G-G Diagram

Currently, the autonomous driving technique is attracting increasing research focus from all over the world. Generally, the control systems of an autonomous vehicle include environment perception, path planning and path tracking control systems. In this paper, the path tracking control issue of the autonomous vehicle will be focused on. Few of the previous proposed path tracking controllers consider the vehicle driving and handling limit, which degenerates the potential of the autonomous vehicle to finish the desired path as quick as possible. To this end, this paper proposes a path tracking controller for autonomous vehicle, which aims at pushing it to the driving and handling limit. The limit dynamic performance of the autonomous vehicle is represented by the G-G diagram, which indicates the acceleration capability of the autonomous vehicle. The G-G diagram is obtained by phase portrait method and it is validated by a modified FSAE racing car. Finally, a path tracking controller based on the G-G diagram is proposed. The simulation validation results demonstrate the effectiveness of the proposed controller.     

基于案例推理的铁路施工项目投标报价决策研究

基于案例推理的铁路施工项目投标报价决策模型构建与投标报价紧密关联的基本信息、工程特征、中标情况和投标过程四框架案例库,并将最近相邻法和归纳索引法相结合获得项目综合相似度,同时,建立案例维护机制模型保证决策系统的准确性与科学性.研究结果表明:案例调整焦点在于对投标报价的修改及估算;该研究成果对于加强铁路施工项目管理及控制铁路建设投资具有一定实际意义.     

液态多点电喷两用燃料汽车的研究

在内燃机理论和热力学计算的基础上研究了LPG液态多点进气道喷射的燃料供给系统和控制系统的理论,设计了液态多点电喷两用燃料汽车,解决了目前普通汽油汽车改装蒸发预混合式LPG系统后动力性下降、经济性优势不明显及环保性未得到充分利用的问题。通过试验结果证明:液态多点电喷两用燃料汽车具有良好的动力性,明显的经济性优势及达到欧Ⅲ排放要求。     

小波包与神经网络组合的判决反馈均衡算法

以电子战为背景，将小波包变换与RBF网络相结合，提出了一种新的判决反馈均衡算法，并将其应用于雷达信号的处理。仿真结果表明，该算法收敛速度较快，能满足电子战情况下，雷达探测信道均衡的复杂要求。     

花岗岩大粒径级配碎石力学性能研究

花岗岩大粒径级配碎石力学性能优于常规级配碎石,在实际工程中得到应用,但中国规范没有规定大粒径级配碎石的级配范围,工程中采用的级配多为经验级配,存在部分路面性能不稳定的缺点。因此,该文采用泰波法与i法相结合,设计其级配组成,采用重型击实成型方法,由无侧限抗压强度试验、CBR试验、回弹模量试验,探索最大公称粒径为53 mm的花岗岩级配碎石的力学性能。试验结果表明:基于泰波法与i法相结合的级配设计方法要优于单独的泰波法设计方法,初拟级配中n=0.55、i=0.70对应级配的力学性能最佳;8组初拟级配对应力学性能无论最大值或最小值都远远大于规范对普通级配碎石的要求,体现了花岗岩大粒径级配碎石良好的力学性能和应用前景;提升干密度与增大击实功可有效改善花岗岩大粒径级配碎石的力学性能。     

自行式压路机总功率的计算与评价

首先分析自行式压路机总功率的计算方法．并根据压路机在实际工作中的功率谱和载荷谱提出了加权因子评价法；以国内外现有压路机的参数，建立功率回归计算的经验方程评价法及进行回归显著性检验。这两种评价计算方法为压路机的设计和发动机功率选择的合理性提供了依据。     

列车运行图编制专家系统之研究

国内外对计算机编制列车运行图已进行大量研究，并得到不同程度的应用。本文提出建立编图专家系统，对该系统进行了分析，并对其知识表示，推理机制进行了多方面的探讨。