共查询到19条相似文献,搜索用时 46 毫秒
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成都市公路主枢纽信息系统的建设 总被引:1,自引:0,他引:1
文章介绍了成都市道路运输行业在客运,货运,运政三方面运用计算机技术建立的计算机管理信息系统网络,主要论述了货运交易中心信息系统建设和应用情况,提出了根据已经建成的网络信息进一步发展成都公路主枢纽信息系统的设想。 相似文献
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建立和完善公路主枢纽货运系统投资体制 总被引:3,自引:0,他引:3
在分析当前我国公路主枢纽货运系统投资体制现状的基础上,对主枢纽的概念进行重新描述,并给出公路主枢纽货运系统的功能定位。根据公共经济学理论对系统要素按投资来源、投资方式进行了合理划分,在充分借鉴国外公路主枢纽货运系统投资体制的前提下,提出了建立和完善社会主义市场经济条件下公路主枢纽货运系统投资体制的具体建议。 相似文献
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基于耗散结构理论的公路快速货运系统演化机理 总被引:1,自引:0,他引:1
针对公路快速货运系统复杂的人因社会经济系统特性,利用耗散结构理论探讨了公路快速货运系统的开放性、非平衡性、涨落和非线性特征;分析了在公路快速货运系统这样一个非平衡的开放系统中,系统组成要素在非线性作用下产生的“巨涨落”是产生稳定、有序结构的内在机制。应用非线性方程,依据系统耗散机理,以公路快运货物量为系统支配变量,外部经济条件为系统控制参数,基础设施条件为系统影响参数,建立单区域和整个区域条件下的公路快速货运系统演化模型,并分析其演化机理与演化条件,揭示了单区域和整个区域公路快速货运系统的演化特点,为按照客观规律制定保障系统快速发展的相应政策或措施提供参考。 相似文献
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本文通过对当前甘肃省货运服务业发展现状地分析,总结了近几年培育和发展货运服务来所取得的成绩,经验和做法,并从理论上阐述了发展货运服务业在培育公路货物运输市场中的重要作用,另外,根据目前货运服务业中存在的问题,对今后行业管理部门和如何搞好此项工作,提出了发展的思路和对策。 相似文献
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公路货运是中国最重要的货物运输方式,远远超过了水运和铁路运输。在需求持续高涨的同时,公路货运领域的竞争也越来越激烈。一方面人们期望货物的运输更快、更灵活、价格更低廉。这便促使物流公司想方设法地提高效率,确保货运车队平稳、无间断且安全地运行,以在竞争中保持领先。另一方面,货运物流车辆是中国道路上最大的污染源。虽然货运车辆仅占到全国车辆总数的8%,但它们的二氧化碳的排放量却占到了运输相关排放总量的70%。这就使得减少公路货运碳排放成为了实现中国交通低碳化的关键因素之一。 相似文献
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针对公路货运市场的现状,分析和探讨了如何在局部地区发展现代信息业,建立适应本地区运输市场发展的信息服务网,切实推动地区现代物流业的快速,健康发展。 相似文献
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结合区域公路、铁路货运的特点,对可获取的多来源信息进行了分析,并用于基年货运OD矩阵的推算.建立了基于模糊规划理论的多源数据OD推算模型及算法,并通过江苏省综合货运OD推算的实例对多源信息的信息价值进行了分析,用于反馈指导多源信息的进一步收集.结果表明,模糊数学的引入有助于解决多源数据带来的不确定性问题,提高OD推算精度.另一方面,路段流量、子区域OD量,以及集计OD量的数值价值相对较大,而且路段流量当中,高流量数据较随机流量数价值更高. 相似文献
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S.D. Iwnicki S. Stichel A. Orlova M. Hecht 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2015,53(7):995-1033
This paper summarises the historical development of railway freight vehicles and how vehicle designers have tackled the difficult challenges of producing running gear which can accommodate the very high tare to laden mass of typical freight wagons whilst maintaining stable running at the maximum required speed and good curving performance. The most common current freight bogies are described in detail and recent improvements in techniques used to simulate the dynamic behaviour of railway vehicles are summarised and examples of how these have been used to improve freight vehicle dynamic behaviour are included. A number of recent developments and innovative components and sub systems are outlined and finally two new developments are presented in more detail: the LEILA bogie and the SUSTRAIL bogie. 相似文献
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通过北京市开展多年的货运车辆抽样调查,总结了北京市搬家运输、混凝土运输、商品配送、油品运输、长途运输等典型货车运输链,分析运输规律,为城市中心区货运需求调查和货运运力配备需求测算奠定了基础.提出了货车运输链描述指标,并且指出要进一步加强信息化技术手段的应用,积极研究利用新技术、新手段,加强货车运输链深入总结归纳,进一步提高相关信息及管理决策的准确性、科学性,充分发挥决策支持功能. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(8):1339-1365
Freight wagons are usually equipped with the standard Union Internationale des Chemins de Fer pneumatic brake. On long trains, the propagation of the pneumatic signals along the pipe and different braking/loading conditions may produce delays and/or differences in the application of the braking effort along the train. This phenomenon may cause heavy longitudinal forces exchanged between wagons through buffers and draw gear. In particular, the workgroup n.6 (freight trains composition) of the Italcertifer committee has performed some preliminary studies concerning the application of LL braking operative conditions on freight wagons trains travelling on Italian lines. Partners have cooperated in this workgroup; however, in this paper, the attention is focused on methodologies and results concerning the contribution of University of Florence. The results of this activity, coordinated by RFI-CESIFER have been used to emanate the 20/07 rule of the RFI (‘Modifiche alla Prefazione Generale all'Orario di Servizio’) which modify the composition criterion rules of freight trains on the Italian Railways in order to introduce and discipline the application of the LL braking operative condition. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(10):1640-1654
This paper deals with the study of running dynamic effects for a partially filled railway tank vehicle. A computational fluid dynamics model in 2D is established and used to define the motion of the sloshing fluid and the forces generated on the tank, for curving conditions typical of railway freight transport. From these results, an equivalent mechanical model is identified which is able to correctly reproduce the forces generated on the tank. Finally, a mathematical model is defined for the entire freight car, including the bogies with primary suspensions, the tank and a discrete number of equivalent models positioned at different places along the longitudinal axis of the tank. This model is used to simulate the dynamics of the tank for a variety of curve geometries, train speeds and fill levels. By these simulations, derailment and rollover risks are evaluated and the most critical conditions for running safety are defined. Results show that sloshing can increase significantly the risk of tank rollover whereas its influence on the risk of derailment is minor. 相似文献
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为取得公路货运网络的规模经济,提出采用共同配送模式来优化公路货运网络。针对已有运输网络设计模型中对运费函数和路径选择分析的不足,提出包含分段费用函数和最短运输路径选择的公路货运枢纽网络设计模型。通过实例计算,采用共同配送模式的公路货运网络中的货物周转量比采用传统的"点-点"网络模式中的货物周转量增加38.07%;而前者的干线公路运输费用却比后者下降了26.48%。结果表明,采用共同配送模式有利于实现公路货运网络的规模经济,文中提出的运输网络设计模型能较好用于公路货运网络优化中。 相似文献
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该文首先分析了机场货运交通的特点,针对这些与常规交通预测不同的特点,构建了机场货运交通预测模型,模型中不但考虑了机场货邮吞吐量,而且考虑了货运业务的客运需求。最后,以深圳机场规划为例,进行了货运交通预测。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(1):125-141
This paper deals with the study of the nonlinear dynamic behaviour of 2-axle freight wagons in curves, considering the case of one single wagon (neglecting inter-car coupling forces) and of multiple wagons interacting through the buffers and the couplers. A multi-body model of a single wagon and of a three-car assembly is introduced, paying particular attention to the nonlinear and nonsmooth modelling of the suspensions and of the inter-car coupling elements. Using this model, a numerical analysis of the steady-state solution reached after the negotiation of curve transition is presented and bifurcations are identified for some particular values of the curve radius. For the single car case, it is shown that depending on the curve radius and the vehicle speed the carbody may experience severe periodic oscillations at speeds lying in the operating range of the vehicle. For the car-assembly case, it is shown that the coupling forces exchanged by the wagons significantly affect their dynamics in a curve, reducing the amplitude of vibration. 相似文献