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排序方式: 共有1300条查询结果,搜索用时 15 毫秒
971.
Assessing the effects of fiscal systems on investment in shipping by using the discounted cash flow technique has recieved much attention over a number of years. This paper examines the recent change in the business environment of Chinese shipping companies and argues for the relevance of using the same technique in the Chinese context. The technique which has been developed over the years is outlined and the current Chinese and UK fiscal systems applied to shipping are described. Based on the comparison and analysis of the effects of the two systems, some policy implications are made.  相似文献   
972.
A queue-dependent vehicle dispatching rule, with options to use special vehicles (rented, reserve, shared etc.) for relieving long waiting lines, is considered. The transportation system under consideration has one source terminal and a fleet of N regular vehicles. Passengers are assumed to arrive individually at the source terminal according to a Poisson process. An efficient recursive algorithm is derived to analyse the performance of the system. An average cost criterion is used to determine the firm's fleet size and dispatching strategy for a simpler system. This is a variant of a “Random vehicle dispatching with options” rule proposed by Zuckerman and Tapiero (1980).  相似文献   
973.
The globalization of shipping means that the industry needs cosmopolitan managers who can negotiate with—and manage—people of different cultures. The causes and consequences of cultural differences are explained in the paper with particular reference to power differentials and rule orientation. The dangers of stereotypes are high-lighted. Communication problems are discussed in the context of transmitting values.  相似文献   
974.
This paper presents a 94 degrees of freedom non-linear multi-body dynamics model of a vehicle comprising front and rear suspensions, steering system, road wheels, tyres and vehicle inertia. The model incorporates all sources of compliance: stiffness and damping, all with non-linear characteristics. The model is used for the purpose of vehicle handling analysis. A simulation run, pertaining to a double lane change is undertaken in-line with the ISO 3888 standard.  相似文献   
975.
For efficient analysis it is important to choose the proper model that fits the problem that needs to be solved. This paper discusses three pragmatic simulation models for longitudinal behaviour of a passenger car tyre (Steady State, Transient and Rigid Ring) that may be used in e.g. an ABS simulation. The characteristics of the simulation models are evaluated using some simple simulations. Simulations with a quarter vehicle model that includes load transfer effects are carried out to determine the deviation in results between the mentioned tyre models for an ABS application. The results show that the Steady State model may only be used below 10 Hz and that the Transient model is valid up to about 30 Hz. The results from the ABS simulation with the Rigid Ring model are most reliable and are clearly different from the Steady State and Transient model, which indicates that ABS simulations should be carried out with the Rigid Ring model. Additionally it is demonstrated that for tyre behaviour on uneven roads the influence of the tyre belt cannot be neglected.  相似文献   
976.
大众汽车公司的机械式G型增压器   总被引:1,自引:0,他引:1  
WellB.  H 张兆奎 《汽车工程》1994,16(3):161-169
本文介绍了德国大众汽车公司设计、生产的采用螺旋推进压气原理的工作的G型增压器,对其原理、结果及应用作了详细的分析说明。  相似文献   
977.
An inverse solution study of various four wheel steering models is carried out for the purpose of comparison of steering/braking input needed to track a lane change maneuver. Optimal control is used to solve the non-linear inverse problem. Comparisons are made when the vehicle is coasting, when the time required to track the trajectory is minimized with appropriate utilization of brake/traction forces, and in a front wheel lock situation. A rear steering model which produces neutral steering characteristics displayed the best steering behavior with respect to ease of steering.  相似文献   
978.
For railway vehicles having coned wheels mounted on solid axles there is, in general, a conflict between stability of lateral deviations from the motion along the track and ability to steer round curves. However, the three-axle vehicle with zero bending stiffness and with shear elasticity between all wheelsets can satisfy the requirement of perfect steering and for a range of values of equivalent conicity possesses both static and dynamic stability. The static and dynamic stability of the most general form of symmetric three-axle vehicle is investigated, and stability criteria derived.  相似文献   
979.
Non-esterified bio-diesel fuel is more economically feasible than esterified one because of simple manufacturing process that only consists of filtering. Applicability of this fuel on diesel engine with electronic control system was tried and accomplished in a previous research. In this study, optimization adopting a fractional factorial design and response surface methodology was carried out at 25 % and 50 % of engine load in order to verify effectiveness of design of experiment for performance optimization of diesel engine. Pcr and IT mainly affected responses as specific fuel oil consumption and nitrogen oxides regardless of engine load according to the fractional factorial design. Estimations were 310.3 g/kWh of specific fuel oil consumption and 237 ppm of nitrogen oxides at 25 % load, and 233.2 g/kWh of specific fuel oil consumption and 730 ppm of nitrogen oxides at 50 % load according to the response surface methodology. As the results of verification tests, specific fuel oil consumption and NOx were respectively 300.4 g/kWh and 277 ppm at 25 % load, and 236.8 g/kWh and 573 ppm at 50 % load. Since there were small differences between estimations and verifications, adopting Box-Behnken method of the response surface methodology for performance optimization of diesel engine should be considered carefully.  相似文献   
980.
Some vehicle components are developed by setting target weights to the gram level at their design stages to accomplish a lightweight design. Recently, there have been many studies that have focused on lightweight design through the use of ultra-high-strength steels. However, a lightweight design can face many challenges if the reliability of the analysis is not also secured at the design stage. Such challenges include difficulties in coupled analyses when the file formats are different among PAM-STAMP, ABAQUS, and NASTRAN. In this study, we developed a mapping interface that enables mapping between the file formats of various software programs. Buckling analysis was coupled to the forming analysis, in which pre-strain test data were applied in considering the material’s strain hardening, to evaluate the rigidity of the front lower control arm that controls the wheels and transfers loads. The influence of forming effects on endurance was evaluated, and residual stresses around the weld zone were calculated. A comparison of experimental and analytical results indicated that the proposed analysis was highly reliable.  相似文献   
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