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91.
今天,我将冒着一定的风险来预言一些在下一世纪开始阶段,会出现在航运业内的某些事物的形态.很显然,我会着重谈一些IMO活动范围以内的事.  相似文献   
92.
The authors describe the development and application of a single, integrated digital representation of a multimodal and transcontinental freight transportation network. The network was constructed to support the simulation of some five million origin to destination freight shipments reported as part of the 1997 United States Commodity Flow Survey. The paper focuses on the routing of the tens of thousands of intermodal freight movements reported in this survey. Routings involve different combinations of truck, rail and water transportation. Geographic information systems (GIS) technology was invaluable in the cost-effective construction and maintenance of this network and in the subsequent validation of mode sequences and route selections. However, computationally efficient routing of intermodal freight shipments was found to be most efficiently accomplished outside the GIS. Selection of appropriate intermodal routes required procedures for linking freight origins and destinations to the transportation network, procedures for modeling intermodal terminal transfers and inter-carrier interlining practices, and a procedure for generating multimodal impedance functions to reflect the relative costs of alternative, survey reported mode sequences.  相似文献   
93.

Valuation of externalities is a condition for correct investment and pricing decisions in transport. This paper provides a brief survey of the main studies achieved in OECD countries in order to get these valuations. Numerical values for the average social cost of transport are presented. The procedures according to which environment is taken into account in France and Italy are analyzed, and the importance of valuation in these procedures is assessed. Finally, prospects for further research and new developments are expressed.  相似文献   
94.
根据ActiveX Automation技术原理.利用AutoCAD2006提供的类型库。介绍了应用Delphi语言进行AutoCAD2006二次开发的程序设计方法和技巧。  相似文献   
95.
制动电阻器多学科设计优化   总被引:3,自引:0,他引:3  
为了确保机车、动车制动电阻器整体性能提高,以某型号特种内燃动车制动电阻器传热性能、经济性能、质量以及抗热冲击性能为目标函数建立多学科设计优化模型,并充分考虑各学科之间的耦合效应,采用自适应混沌优化算法对多学科设计优化模型进行求解。多学科设计优化结果表明,该制动电阻器传热性能增加11.51%,设计成本下降7.05%,质量减少7.21%,抗热冲击性能增加15.50%,整体性能提高9.97%。优化前后特种内燃动车制动电阻器的安全温度对比实验表明,制动电阻片的安全温度由优化前的500℃提高到优化后的550℃。  相似文献   
96.
97.
An analytical study is made of the determination of the travel intensity at an arbitrary point of a city with a straight line barrier. For a given origin and destination a trip is made by the shortest path not crossing the barrier or the city perimeter. The joint trip end distribution is arbitrary except for a continuity assumption.  相似文献   
98.
The characteristic equation for a simple automobile-trailer combination is analyzed, revealing the parameter groups which are important in determining the stability characteristics. Application of Routh's method results in separate criteria for oscillatory and non-oscillatory criteria which can be evaluated algebraically, and which can also be displayed graphically showing a region of stability on a two-dimensional plot. The stability region is bounded by limits of oscillatory and non-oscillatory stability, and the evaluation of a specific case corresponds to the location of a point relative to the boundaries.  相似文献   
99.
INVITROGLYCATIONOFHEMOGLOBIN(HB):CHOOSINGTHEAPPROPRIATEMODELFangZhiyu;R.R.Little,H.M.Wiedmeyer,D.E.Goldstein(DepartmentofChil...  相似文献   
100.
Characteristics of Guided-Steering Railway Trucks   总被引:1,自引:0,他引:1  
The dynamic characteristics of guided-steering railway trucks are described both in a general sense and in terms of a specific design. Stability margins and curving performance have been predicted and are compared for both conventional and steered vehicles. It is shown that guided-steering trucks exhibit modes of instability which, although surmountable by proper design, are not found in conventional trucks. In particular, a low conicity, divergent, leading truck instability is described together with a companion high conicity, divergent trailing truck instability. Curving and dynamic performance for steered vehicles is shown to have the potential of being far superior to that of comparable conventional vehicles. Factors influencing the design of steered rail vehicles are presented and discussed.  相似文献   
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