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601.
张樟进 《西安交通大学学报(英文版)》1995,(2)
LOSSOFNUCLEUSBASALISMAGNOCELLULARIS,BUTNOTSEPTAL,CHOLINERGICNEURONS CORRELATESWITHPASSIVEAVOIDANCEIMPAIRMENTINRATSTREATED WIT... 相似文献
602.
If international container ports are to gain a proper appreciation of their various advantages, disadvantages and potential opportunities in a globally competitive environment, it is essential that they conduct effective evaluation of their operational performance. The present study applies five models of data envelopment analysis (DEA) to acquire a variety of complementary information about the operational efficiency of major container ports in the Asia-Pacific region and to identify trends in port efficiency. The study first establishes the causes of inefficiency on the basis of efficiency value analysis. Slack variable analysis is then used to identify potential areas of improvement for inefficient ports. This is followed by the utilization of return to scale analysis to assess whether each port is in a state of increasing, decreasing, or constant return to scale. Finally, a sensitivity analysis is conducted to identify which input or output variables have larger weights in terms of efficiency. The results provide valuable information for port managements in their attempts to establish competitive strategies for the future and to improve their resource utilization for ongoing improvements in operational efficiency. 相似文献
603.
J. Gao N.J. Leighton C. Morgan 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1998,29(4):261-273
An alternative technique for identifying the transfer function of automotive suspension systems is presented in this paper. The method establishes a frequency response from which the transfer function can be determined by using a low cost test rig developed for the purpose. This results in a transfer function matrix which can include asymmetry in the suspension, tyre stiffness and damping. The technique is validated by comparing results for a two-wheeled trailer with those obtained on a conventional hydraulic test rig. Results from this procedure may be used to evaluate passive or active suspension systems or to feed into a suspension modelling process for such purposes as active suspension control strategy development. 相似文献
604.
605.
Safety mechanism is required for an automotive battery pack to prevent thermal failure which could lead to catastrophic events. Passively cooled battery packs can prevent thermal failure by conducting adaptive control of battery power without any external cooling device. The key to this power control is how to secure battery safety while minimizing energy loss. This paper proposes a novel, adaptive power control strategy for automotive passive-cooling battery packs. Four different cases with electrochemical battery model are simulated and compared to each other according to a city driving profile. Driving simulation result confirmed that the present power control algorithm is an effective solution for preventing thermal failure along with improving energy efficiency of automotive battery packs. 相似文献
606.
Nearly 90% of the traffic accidents that occur worldwide happen in developing countries. Yet road safety remains a little-studied subject in these countries, and notably accidentology studies, which provide a wealth of information. One of the major problems in studying road accidents in developing countries lies in the lack of reliable accident data. Indeed, while the comprehensive accident analysis methodologies used in developed countries provide an understanding of the origin of accidents and accident processes, as well as making it possible to define suitable, effective actions, they require reliable and relatively detailed accident data. These methodologies are notably based on detailed accident studies (DASs) and their adaptation to the analysis of accident reports. Colombia has an infrastructure for gathering and storing traffic accident data that can be used to perform comprehensive accident analyses. This article defines the feasibility of a technology transfer (clinical accident analysis) to the Colombian equivalent of accident reports. These observations are part of a doctoral thesis prepared jointly by the IFSTTAR Accident Mechanisms Research Unit and the University of the Andes in Bogotá. 相似文献
607.
在市场经济条件下,发展俄罗斯的高速铁路运输业是很迫切的任务。由于客车运行速度的提高,与其他形式的高速工具相比,即使2站间的运输距离很长,铁路运输的竞争力也在不断增强。然而,摆在面前的突出问题是要提高列车运行的安全性,解决这个问题,在很大程度上取决于制动系统的工作效率和工作稳定性。 相似文献
608.
介绍了西班牙Talgo 350动车组设计原则、车体倾摆系统、牵引和制动以及内部装备的新技术。 相似文献
609.
Fu H.-L.Hu C.-C.Lin R.Huang Z.Zhang J.-B.Shi Y. 《铁道工程学报》2018,(11):48-54
Research purposes: In the construction process of curved shield tunnels, the force of excavation face is extremely complex and the stability is difficult to control, so it is very likely that the thrust of the jack will cause uplift of the soil in front because of passive failure. Taking the sand strata as an example, this paper established a combination model of "inverted ladder-wedge prism" to reveal that the soil in front of the excavation face of curved shield tunnels uplifts up because of passive failure based on the silo theory and limit equilibrium method, and deduced the calculation method of passive limited supporting force for curved tunnels. Then, we confirmed the accuracy and reliability of this model and calculation method through programing and simulating. Research conclusions:(1) The passive limited supporting force increases with the increase of buried depth and internal friction angle, and the growth rate gradually increases. (2) When the radius of the line is less than 200 m and the internal friction angle is more than 25 degrees, the passive limited supporting force is very sensitive to the curvature radius, and when the radius is more than 800 m, the passive limited supporting force is almost no difference with straight tunnels. (3) The numerical results indicate that the numerical solution is consistent with the theoretical solution and the difference is quite small. (4) The research results can provide theoretical basis for determining the passive limited supporting force in the constructions of similar curved shield tunnels especially small turn radius shield tunnels. © 2018, Editorial Department of Journal of Railway Engineering Society. All right reserved. 相似文献
610.
Research purposes: In recent years, tunnel diseases like lining cracking and water leaking during spring thawing period, caused by frost heaving of surrounding rock, have occasionally occurred in high-latitude seasonally-frozen regions of northwest China and northeast China, which has seriously affected the tunnel structure and operation safety. Taking several railway tunnels in northwest China as an example, this paper investigates the cause and main influencing factors of longitudinal cracking of side wall in winter in seasonal frozen soil area by means of field test, laboratory experiment and numerical simulation. Research conclusions:(1) When the water content of surrounding rock of tunnel built in strongly-weathered sandstone is 12.3% and the frozen depth of surrounding rock is up to 60 cm, the maximum tensile stress of side walls is 2.28 MPa, which is larger than the ultimate tensile strength of C30 concrete, then the horizontal lining cracking will appear on side walls under the effect of continuous negative temperature in winter. If the lining bears part of the surrounding rock load, the longitudinal cracking degree of the side wall will increase. (2) Under the effect of frost heaving loads, the cracking of tunnel lining has its own characteristics of symmetry, seasonality and accumulation, etc. The cracks appear in winter and distribute in the middle of side walls. As the temperature is rising, the crack begins to shrink. (3) The frozen circle thickness and water content of surrounding rock should be used as main indicators during the process of calculation of frost heaving loads of surrounding rock in seasonally-frozen regions. (4) The research results can be used for reference in tunnel design, operation and maintenance in seasonal frozen soil area. © 2018, Editorial Department of Journal of Railway Engineering Society. All right reserved. 相似文献