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611.
Thromboembolicdiseasesareamajorcauseofmorbidityandmortality.Thepathogenicmechanismsofthediseasesre-mainunclear.Fourfactors,in... 相似文献
612.
K. Riedl P. Lugner 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1982,11(3):175-193
Detailed Investigations of the Steady State Turning of Single Track Vehicles
In the paper the steady state turning of single track vehicles on a horizontal, even road is investigated, supposing the air to be at rest. The vehicle model used has six degrees of freedom: rolling, yawing, pitching and bouncing of the vehicle, rotation of the front wheel system (steering) relatively to the main frame and distortion of the rear wheel system due to limited stiffness of its linkage, and also takes into account wind drag and gyroscopic effects generated by wheels and other vehicle components. A special importance is given to the geometry of the vehicle
The results show a comparison of two types of motorcycles with different geometries and tires. To characterize the vehicle behaviour the roll, side slip and steering angle as functions of the normal acceleration are used. A more detailed study in respect to the steering torque is added. 相似文献
In the paper the steady state turning of single track vehicles on a horizontal, even road is investigated, supposing the air to be at rest. The vehicle model used has six degrees of freedom: rolling, yawing, pitching and bouncing of the vehicle, rotation of the front wheel system (steering) relatively to the main frame and distortion of the rear wheel system due to limited stiffness of its linkage, and also takes into account wind drag and gyroscopic effects generated by wheels and other vehicle components. A special importance is given to the geometry of the vehicle
The results show a comparison of two types of motorcycles with different geometries and tires. To characterize the vehicle behaviour the roll, side slip and steering angle as functions of the normal acceleration are used. A more detailed study in respect to the steering torque is added. 相似文献
613.
A. Horn P. Voelsen 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1981,10(1):1-19
Vehicle Handling Characteristics and Their Relationship to Vehicle Design Parameters
This paper reviews currently used test procedures for the determination of vehicle handling characteristics in the time and frequency domain. Driver subjective opinions lead to preferred tendencies or ranges of these quantities. The results of closed-loop tests show the adaptability of drivers to the dynamic characteristics of vehicles. The relationship between handling characteristics and design parameters is obtained from the analysis of a simple vehicle model. Comparison of these results with the prefered ranges found in closed-loop tests yields aids for the design of vehicles. 相似文献
This paper reviews currently used test procedures for the determination of vehicle handling characteristics in the time and frequency domain. Driver subjective opinions lead to preferred tendencies or ranges of these quantities. The results of closed-loop tests show the adaptability of drivers to the dynamic characteristics of vehicles. The relationship between handling characteristics and design parameters is obtained from the analysis of a simple vehicle model. Comparison of these results with the prefered ranges found in closed-loop tests yields aids for the design of vehicles. 相似文献
614.
P. T. J. Splerings 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1981,10(1):21-35
By means of a mathematical model the effects of lateral front fork flexibility on the vibrational modes of single-track vehicles have been studied. The analysis performed by Sharp has been used as a starting point. The results have been compared with Roe's empirical findings. The results of the analysis have been translated into practical advice for a more optimal front fork construction. 相似文献
615.
Inadequate ports are a major problem in many less developed countries (LDCS). In an era in which international trade involving developing countries is growing rapidly, decisions must be made to provide the necessary infrastructure and superstructure to facilitate the movement of cargo from ship to shore and vice versa. In LDCS, the phenonmenon of the Combined Naval-Commercial Port (CNCP) has not undergone scrutiny. This paper is concerned with describing the nature of the Latin American CNCP. The hypothesis is that commercial port interests have been adversely affected by coexistence. The results of an unquiry comprise the main body of this research. 相似文献
616.
This paper derives several well-known spatial models in a framework based upon the laws of conditional probability analysis. In particular, it relates the structure of some existing models of trip distribution, elementary residential location and residential location with capacity constraints, to either the multinomial or hypergeometric probability distributions. The major changes from traditional methods for developing these models deal with the derivation and form of the objective function for each interaction model. This alternative analysis reaches a wider audience than that only familiar with entropy methods and leads to several improvements in generality. Further, when population constraints were imposed on residential location models, it was found that the model which developed naturally from the approach taken in the paper contained as a special case the model proposed by Dacey and Norcliffe and not the Wilson model. 相似文献
617.
克诺尔机车车辆制动公司开发了模块化的标准制动控制系统MBS,只需较少的费用就可适应欧洲铁路运输企业的各种不同要求。制动系统必须按用户的专门要求来开发。可适配的模块化MBS系统可用于欧洲各国的跨境运输,能满足欧洲不同的安全性规定。系统具有重量轻、所需安装位置小、寿命周期费用低、机车车辆使用率高的优点。Bombardier公司、德国铁路公司、瑞士和奥地利联邦铁路已从中获益。 相似文献
618.
At great scales of time and space, the dynamics of the Mediterranean Sea, a concentration basin, are mainly linked to its freshwater budget. This budget is subject to evolutions due to man's use of freshwater and to climatic changes affecting precipitation and/or evaporation. Marine dynamics and Atlantic, atmospheric and terrestrial inputs are strong constraints for the geochemical behaviour of the Mediterranean Sea. From measurements made during the last decades in the deep western water, it appeared that temperature, salinity, nutrients and trace metal concentrations were changing with time. In spite of its depth, the Mediterranean Sea looks like a coastal ocean, according to its coast length, watershed and number of inhabitants and to its fast response to climatic and environmental changes. The changes discovered in deep homogeneous waters are signatures of evolutions occurred in the surface layer. But in this layer and particularly in coastal waters, climatic and/or environmental trends may be masked by seasonal and interannual variabilities of not only physical and chemical characteristics but also climatic forcing or anthropic inputs. Analyses of river runoff, atmospheric inputs or climatic trends together with marine evolutions indicate constraints concerning probable changes in the coastal sea and/or in the surface water and processes involved at the interfaces. Moreover, changes observed in coastal or deep-water constitute new constraints for the modelling of the marine circulation and the transfer of matter. 相似文献
619.
C. P. Keizer 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1979,8(4):359-406
An important function of a bogie of a railway vehicle (or of the running gear of guided vehicles in general) is to guide or steer the vehicle along the course of the track while isolating the vehicle and its payload as well as possible from unintended but inevitable imperfections in the position of the track. Against this background, an analytical expression is derived for the low speed transfer function of a bogie, from which conclusions can be drawn regarding the effect of the elastic connections between wheelsets on dynamic behaviour. At higher speeds inertia effects of the unsprung masses have a negative effect on dynamic behaviour, the magnitude of this effect being different for different types of elastic connections. This is also reflected in the critical speed and the interaction between body and bogie. With respect to the wear of wheels and rails on curved track, the range of radii of curves which can be traversed without flange contact and, for smaller radii, the rate of increase of flange force and angle of attack of the leading wheelset are important factors. Some expressions are derived for the effect of the elastic connections between wheelsets on these factors. 相似文献
620.