锦白铁路扩能工程牵引方式的研究

牵引方式是铁路主要技术标准之一,合理的牵引方式能够为国民经济的发展带来巨大的效益。锦白铁路是一条以煤炭运输为主的货运铁路,运量到发地集中,通道独立性高,运量增长潜力大,采用电力牵引优势明显,这也符合国家能源政策及铁路规划,且运营期的费用较内燃牵引节省程度大,投资回报率高,回收期短,所以本线的牵引方式宜采用电力牵引。     

现代有轨电车售检票系统方案的研究

简要分析地铁售检票模式、快速公交售检票模式和公交汽车售检票模式的特点,结合分析现代有轨电车售检票系统技术的特点。以此为基础,从现代有轨电车售检票方案、系统票制方案、车票方案等方面内容重点阐述现代有轨电车售检票系统方案的研究。     

兰新高速铁路综合维修天窗设置方式研究

在分析兰新高速铁路的线路、运输组织、车站、接触网、综合维修、供电制式等方面特点的基础上,研究兰新高速铁路综合维修天窗的时间需求,重点确定兰新高速铁路天窗开设方式,建议采用分段矩形天窗。并通过铺画列车运行图,分析兰新高速铁路开设分段矩形天窗对跨线旅客列车终到时间、通过能力、运行调整等方面的影响。按客流区段设置分段矩形天窗可以保证综合维修作业和行车的安全。     

Unraveling the relationship between trip chaining and mode choice: evidence from a multi-week travel diary

Abstract

Trip chaining (or tours) and mode choice are two critical factors influencing a variety of patterns of urban travel demand. This paper investigates the hierarchical relationship between these two sets of decisions including the influences of socio-demographic characteristics on them. It uses a 6-week travel diary collected in Thurgau, Switzerland, in 2003. The structural equation modeling technique is applied to identify the hierarchical relationship. Hierarchy and temporal consistency of the relationship is investigated separately for work versus non-work tours. It becomes clear that for work tours in weekdays, trip-chaining and mode choice decisions are simultaneous and remain consistent across the weeks. For non-work tours in weekdays, mode choice decisions precede trip-chaining decisions. However, for non-work tours in weekends, trip-chaining decisions precede mode choice decisions. A number of socioeconomic characteristics also play major roles in influencing the relationships. Results of the investigation challenge the traditional approach of modeling mode choice separately from activity-scheduling decisions.     

Hydrodynamics of a body floating in a two-layer fluid of finite depth. Part 1. Radiation problem

A linearized 2-D radiation problem was considered for a general floating body in a two-layer fluid of finite depth. A boundary integral-equation method was developed for directly computing the velocity potential on the wetted surface of a body which is immersed in both the upper and lower layers as a general case. To do this, appropriate time-harmonic Greens functions were derived, and an efficient numerical method of evaluating those functions is proposed. Based on Greens theorem, hydrodynamic relations such as the energy-conservation principle were derived theoretically for a case of finite depth, and we confirm that those relations are satisfied numerically with very good accuracy. Experiments were also carried out using water and isoparaffin oil as the two fluids and a Lewis-form body. Measured results for the added mass, the damping coefficient, and the amplitude of the generated waves are compared with the computed results, and a favorable agreement is found.     

高速公路项目管理模式评价

随着我国高速公路建设的迅速发展,如何选用合适的高速公路项目管理模式,以提高高速公路项目管理的科学性和有效性,一直是高速公路项目管理中非常重要的研究课题。本文试图提出高速公路项目管理模式评价的指标体系,并利用层次分析法的原理,通过构造层次分析模型对我国主要的高速公路项目管理模式进行评价,为改善我国高速公路项目管理和促进我国高速公路的建设提供一定的理论基础。     

平动模式下挡土墙非极限状态主动土压力计算

改进了极限平衡理论,用于非极限状态主动土压力的研究。对挡土墙后滑动楔体的片体单元进行了分析,建立了关于非极限状态主动土压力强度的一阶微分方程,得到了平动变位模型下,非极限状态主动土压力强度、土压力合力和土压力合力作用点的理论公式,将计算所得结果与模型试验数据进行对比分析。结果表明:墙体平动变位模式下非极限状态主动土压力强度、土压力合力和土压力合力作用点理论公式的计算结果与已有模型试验结果基本吻合。     

静水压作用下半圆环壳的非轴对称屈曲

本文根据Ｂ．Ｂ．诺沃日洛夫~［１］薄壳理论,应用圆环壳稳定性控制方程,采用幂级数法求解 了静水压作用下半圆环壳非轴对称屈曲问题的屈曲载荷及屈曲模态。     

公路膨胀土加筋地基承载力计算方法研究

结合公路膨胀土加筋地基的受力特点和作用机理及其破坏形式,对国内外常用的公路膨胀土加筋地基承载力的计算方法进行了深入分析,在此基础上,筛选出了适宜于我国公路膨胀土加筋地基承载力计算的宾奎特法和改进的太沙基法及深基础效应法,这对公路膨胀土加筋地基的设计具有重要的指导作用.     

斜拉桥结构体系可靠性评估理论研究进展

介绍斜拉桥结构体系可靠性评估理论的发展概况,对国内外具有代表性的评估方法进行了系统的分析,重点阐述了斜拉桥结构体系可靠性评估方法的整体框架及其工程应用。在此基础上,讨论了斜拉桥结构体系使用安全可靠性评估领域存在的一些问题和发展方向。