城市轨道交通电动列车司机值乘方案的优化

以上海轨道交通3号线为例,对电动列车司机值乘的包乘制、轮乘制按实际效果和使用成本进行了优缺点分析;并在此基础上对司机作息安排、人员配置、运作管理情况综合进行优化,以期达到网络运营后节约人力成本的作用.     

基于SVM的二叉树多类分类算法在工程车辆挡位决策中的应用

为了解决工程车辆挡位决策这种典型的多类分类问题,在介绍自动变速器挡位决策基本原理的基础上,提出基于SVM的二叉树多类分类的挡位决策算法,将分类器分布在各个节点上,从而构成了多类SVM,并在制定换挡策略时,考虑了工作油泵所消耗发动机功率的波动问题。试验结果表明:该方法可根据车辆运行状态确定最佳挡位,从而及时准确地满足工程车辆自动换挡要求。     

Load-leveling suspension system with a magnetorheological damper

In this paper, a load-leveling suspension system with a magnetorheological (MR) damper is investigated. In this suspension system, the MR damper is connected to a spring to form a load-leveling suspension system. The system effective stiffness and damping can be adjusted by controlling the MR damper. The characteristics of a load-leveling suspension system are studied first. When the linear damper is replaced with an MR damper, the averaging method is adopted to obtain the steady-state response of the nonlinear system. A comparison demonstrates that the results of the averaging method are in good agreement with those obtained by numerical simulations. The analytical results are then verified experimentally. The load-leveling suspension system studied here is able to adjust both suspension stiffness and damping and, hence, it may provide more effective vibration control in a wider frequency range, when the damper is controlled.     

时速350 km/h铁路客运专线桥梁设计中应注意的几个方面

高速列车对桥梁结构的动力作用远大于普通铁路桥梁,桥梁出现较大的挠度会直接影响桥上轨道的平顺性,造成结构物承受很大的冲击力,并且会影响到列车的运行安全,其中设计活载图式的选择,离心力以及结构的变形变位,梁体的自振频率都会对桥梁的安全存在影响,因此,这些方面都是在设计中应该注意的。     

单环非互易铁氧体移相器

为了研制自动跟踪同步通信卫星平板相控天线阵系统,对相控阵天线中的关键元件单环非互易铁氧体移相器进行了研究。利用双平板模型推导出了单环非互易铁氧体移相器的超越方程,并对其特性进行了讨论。根据超越方程对单环非互易铁氧体移相器的差相移随铁氧体厚度的变化进行了数值计算。结果表明随铁氧体厚度的增加,它的差相移增加。     

共享单车影响下小汽车出行方式转移机理研究

从小汽车到共享单车参与的出行模式转变是解决交通与环境问题的有效方法之一.本文通过对南京市 308名小汽车出行者进行问卷调查,探讨了共享单车影响下心理因素对小汽车出行模式转移的影响.通过建立改进后的技术接受模型,研究了感知有用性,感知易用性和感知健康价值对共享单车的态度,以及对出行方式转移意愿的影响.结果表明,通过作用于共享单车的态度,感知健康价值和感知易用性对转移意愿产生积极影响,感知有用性则产生直接的积极影响.共享单车可以在短途出行中替代小汽车,中距离下出行者最有可能受到激励从小汽车用户转变为潜在的共享单车接驳公共交通使用者,而长距离下共享单车较难影响小汽车出行者的出行方式选择.     

27t轴重通用货车应用下调车场连挂区调速控制研究

27 t轴重通用货车的应用给调车场连挂区调速控制提出了新问题。分析27 t轴重通用货车单位基本阻力更小、溜放动能更大等特点,减速顶对27 t轴重通用货车制动功的减小、临界制动速度的上浮等特性,以及与既有货车混合应用后超速连挂风险的增加、调速控制复杂性的增大等问题。通过模型建立、参数标定及仿真计算,得到减速顶对27 t轴重通用货车制动功的减幅及临界制动速度的漂移量。为解决27 t轴重与既有货车混合应用下调车场连挂区调速控制问题,提出3种调速控制方案,仿真计算显示,在满足27 t轴重通用货车调速控制、难行车不利溜放、最短溜放距离等约束下,增加布顶与调整坡度相结合的方案最优。     

含大量块石、碎石回填土强夯地基加固效果检测

通过某一工程实例来说明采用载荷试验、动力触探试验、瑞利波试验检测含大量块石、碎石回填土强夯地基加固效果。     

Efficient estimation of extreme long-term stresses by considering a combination of longitudinal bending stresses

Longitudinal stresses due to combined horizontal and vertical bending moments in ships, corresponding to a return period of 20 years, are estimated by linear response analysis. In principle, the stress should be obtained by combining the stress in all sea states that can occur over a long-term period. A method to determine the desired long-term extreme stress by considering only a few short-term sea states is presented. The sea states have a certain probability of occurrence, and are each identified by a contour line in the (H _s, T _p)-plane. This approach makes it possible to estimate the extreme loads on the vessel in a practical and accurate manner. Moreover, it is shown that the long-term stress can be estimated by combining the individual long-term extreme stresses due to vertical and horizontal bending moments by using the sum-of-squares approach and accounting for the correlation between stresses. It was found that the correlation coefficient can be taken as the largest of the ones calculated along the contour line. It is shown that this correlation coefficient can even be approximated by the normalized phase angle at the wave length where the dominant response has its peak value. A comparison with the results obtained using well-known combination rules is presented. While linear analysis has been used here, it is believed that the approach can be generalized to stresses with nonlinear behavior, and hence represent a significant improvement in calculation efficiency. Received: September 18, 2001 / Accepted: December 18, 2001     

旁瓣抑制下的编码信号选取方法

雷达系统中,相位编码信号对多普勒频率非常敏感。根据相位编码信号的这一特点,对于旁瓣抑制条件下的相位编码信号,介绍一种综合选取法,对其进行码型设计,以达到尽量降低旁瓣抑制滤波器对于信号多普勒性能的影响的目的,并与传统的利用最优码设计编码信号码型的性能进行比较。