关于西柏坡公路设计中生态环境保护措施的探讨

为将西柏坡公路修建成一条生态环保的红色旅游路,在设计阶段,合理设置桥梁隧道及因地制宜的将路基上下行分离,并采取科学的排水防护设计及符合实地条件的绿化措施,为工程建设打下良好的基础。     

汽车复合材料板弹簧的有限元分析及性能测试

利用ABAQUS有限元软件,对设计的某型号汽车复合材料板弹簧进行了有限元分析,计算了复合材料板弹簧的刚度系数和最大承载力,并对采用模压工艺制备的复合材料板弹簧样件进行了性能测试.计算与试验对比表明,计算结果与测试结果吻合较好;设计的复合材料板弹簧的主要性能指标达到设计要求,且复合材料板弹簧可比钢板弹簧减重约63％.     

主路不同流量条件下入口匝道通行能力研究

详细分析入口匝道和无信号控制交叉口交通行为的异同之处,借鉴无控制交叉口通行能力的诸多研究成果,运用接受间隙理论分析研究入口匝道通行能力,提出主路在低流量、中等流量和高流量时下车头时距分别服从移位负指数分布、2阶Erlang分布和3阶Erlang分布。考虑不同类型车辆汇入的临界间隙和跟车时距,建立主路不同流量条件下的入口匝道通行能力模型。求出相应条件下混合车流的入口匝道通行能力值,为高速公路及城市快速路的入口匝道控制以及系统控制提供基础信息。     

单向交通条件下信号交叉口通行能力计算方法

为科学合理地指导单向交通的规划和设置,对单向交通条件下信号交叉口通行能力的计算问题进行探讨。在进行单向交通对交叉口交通影响分析的基础上,对不同信号相位、不同单向交通设置形式进行分类讨论并给出计算公式。最后通过具体实例的计算比较,证实给出的计算公式具有较高精度,可为行业标准及规范的制定提供参考。     

基于车队法的双车道无控制交叉口通行能力分析

交叉口通行能力是通行能力研究的重点和难点,本文将双车道无控制交叉口中各个方向的车流看作相对独立的车队,然后分别对交叉口中两两相冲突的车流运用车队分析方法进行分析研究,并对其通行能力进行修正,从而得到不同方向车流相穿插的通行能力,最终得到了一种基于车队法的双车道无控制交叉口通行能力的计算方法。     

沈大高速公路改扩建工程的生态环境保护措施

介绍了沈大高速公路改扩建工程中采取的生态环境保护措施:选择合理的建设方案减少对地表植被的破坏并避免产生沥青固体垃圾;采取了有效的工程措施减少水土流失;公路绿化和景观与周围环境相协调.     

A constraint programming model with time uncertainty for cooperative flight departures

The lack of a proper integration of strategic Air Traffic Management decision support tools with tactical Air Traffic Control interventions usually generates a negative impact on the Reference Business Trajectory adherence, and in consequence affects the potential of the Trajectory-Based Operations framework. In this paper, a new mechanism relaying on Reference Business Trajectories as a source of data to reduce the amount of Air Traffic Controller interventions at the tactical level while preserving Air Traffic Flow Management planned operations is presented. Artificial Intelligence can enable Constraint Programming as it is a powerful paradigm for solving complex, combinatorial search problems. The proposed methodology takes advantage of Constraint Programming and fosters adherence of Airspace User’s trajectory preferences by identifying tight interdependencies between trajectories and introducing a new mechanism to improve the aircraft separation at concurrence events considering time uncertainty. The underlying philosophy is to capitalize present degrees of freedom between layered Air Traffic Management planning tools, when sequencing departures at the airports by considering the benefits of small time stamp changes in the assigned Calculated Take-Off Time departures and to enhance Trajectory-Based Operations concepts.     

Post-entry container port capacity expansion

Port capacity development is a critical strategy for the growth of a new port, as well as for the development of existing ones, when both new and existing ports serve the same hinterland but have different competitive conditions. To study this strategy, we develop a two-stage duopoly model that comprises the pricing and capacity decisions of two heterogeneous players serving an increasing market. We identify the necessary condition for a port to increase its profit through capacity expansion, and characterize the condition when preemptive pricing by the dominant player is neither credible nor effective in preventing the smaller player from gaining market share. We also find the pure-strategy Nash equilibrium in the capacity expansion game for two ports that have different price sensitivities, as well as different operation and capacity investment costs. We apply the model results to the container port competition between Hong Kong and Shenzhen after Shenzhen port started its container operation in 1991. Our analysis explains the transition of market power from monopoly to duopoly, the fast development of Shenzhen Port, and the possible market structure changes with the continuing increase in demand.     

改扩建高速公路基本路段通行能力研究

文章以沪宁高速公路江苏段桩号为K104＋925两侧加宽（两侧拼接）的扩建基本路段为研究对象,利用VISSIM仿真软件,建立高速公路基本路段仿真模型,模拟车流的运行状态及其随时空变化的过程。通过对仿真运行过程的观察及实测数据的分析,对比研究了扩建前后高速公路基本路段的实际通行能力和服务水平。     

电分相对区间信号机布置的影响

分析了各种列车编组以不同速度通过电分相的情况,通过计算所需要的走行时间和距离,提出了起动距离的计算公式。当通过信号机需要布置在电分相附近时,电分相对行车安全和通过能力会产生重要的影响。结合不同的线路条件,详细描述了这些影响,并且通过合理的区间信号机布置来解决这一问题。