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981.
Characteristics of Guided-Steering Railway Trucks 总被引:1,自引:0,他引:1
R. E. Smith R. J. Anderson 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1988,17(1):1-36
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
982.
To plan new bus routes in suburban areas, expected bus running times on these routes are needed. Using most readily available relevant variables, a regression model is developed for estimating bus running times. The model is conceptually reasonable and it was tested using data other than that used for estimation. 相似文献
983.
H. Malchow 《Journal of Marine Systems》1996,7(2-4)
Nonlinear interactions, diffusion, transport and locomotion of species are described by a system of reaction-diffusion-advection equations. Its transient and stationary nonequilibrium solutions in space and time are considered as patchy patterns in natural chemical or biological communities. Recent results on the general mechanism of spatial pattern formation after flux-induced instabilities of a spatially uniform species distribution as well as on the effect of hydrodynamic forcing on spatial patterns in a minimal plankton model are summarized. 相似文献
984.
实验用神经内微记录和微刺激相结合的方法,对人体桡神经浅支支配的有毛皮肤所属机械感受性单位的特征和诱发感觉的性质进行了观察。在47个感觉单位中,SA单位占74.5%,其中SAⅠ61.7%,SAⅡ12.8%,RA单位占25.5%,没有发现毛囊单位和PC单位。SA单位的平均机械阈值高于RA单位,RA和SAⅠ单位的感受野明显小于SAⅡ单位。神经内微刺激诱发感觉的性质取决于所兴奋单位的类型,RA单位产生间断的跳动感,SAⅠ单位产生持续的压感;而SAⅡ单位在单独兴奋时不产生特定的感觉。结果提示:人体桡神经浅支支配的有毛皮肤机械感受性单位的特征与无毛皮肤没有明显差别。 相似文献
985.
M.J. Smith 《Transportation Research Part B: Methodological》1982,16(1):1-3
We consider the traffic equilibrium problem when the travel demand is inelastic and stationary in time. Junction interactions, which abound in urban road networks, are permitted. We prove that the set of equilibria (solutions to the assignment problem) is convex when certain monotonicity and continuity conditions are statisfied at each junction. 相似文献
986.
987.
J. R. Ellis P. L. Read 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1976,5(4):205-219
The paper describes the development, operation and some of the results obtained from a simulation of the steering behaviour of the double bottom articulated vehicle, in particular the effects that arise when certain axles are locked. 相似文献
988.
John L. Eyre 《Maritime Policy and Management》1989,16(3):179-187
Over 60% of ocean trade moves in ships with convenience flags, those of Liberia, Panama, Cyprus and others. Semi-detached flags of Norway, France and the UK are another of the growing devices for avoiding rich-country taxes and labour costs. Shipowners and their customers see little hope for change (taxes and labour) in their political climates at home, but they need some workable governing structure to assure safety, payment of bills, protection of the environment and decent service. It follows that all maritime nations, especially the USA and Canada, should pay more attention to the creation and observance of International Conventions. 相似文献
989.
Jacques J. Charlier 《Maritime Policy and Management》1989,16(3):233-246
Elementary and generalized specialization indexes are used to detect structural change and its processes in the Ro-Ro traffic between the United Kingdom and Continental Europe. Powered vehicles dominate British exports through Channel and Straits ports, whereas unaccompanied trailers have the lead for traffic through North Sea ports. A major structural change took place on the continental side, where both forms of traffic came to a new balance in the Belgian ports between 1977 and 1987 in an otherwise stable market share context. 相似文献
990.