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通过对广州地铁2号线使用的干式变压器进行预防性试验的总结分析,阐明预防性试验是检查设备潜在缺陷唯一的一种手段,设备在运行中有异常情况时,可运用预防性试验来对其状况做正确判断,并发现设备的潜在缺陷,对没有缺陷的设备也能做出正确的判断。 相似文献
994.
The equilibrium properties of an aggregate taxi market are investigated using a general bilateral searching and meeting function which characterizes the search frictions between vacant taxis and unserved customers. Three specific issues are analyzed for meeting functions that exhibit increasing, constant and decreasing returns to scale. Firstly, service quality in terms of customer wait/search time and average profit per taxi are examined jointly in relation to taxi fleet size, and a Pareto-improving win-win situation is identified, where an increase in taxi fleet size leads to improvements in both service quality and market profitability. Such a Pareto-improving situation is found to emerge if and only if the meeting functions show increasing returns to scale. Secondly, the properties of the socially optimal solution are examined. It is found that the taxi fleet size should be chosen such that the total cost of operating vacant taxis equals the total cost of customer waiting time multiplied by an asymmetric factor of the meeting function, and that taxi services should be subsidized at social optimum only when the meeting functions show increasing returns to scale. Thirdly, the Pareto-efficient services are examined for trade-offs between social welfare and profits in the light of partially conflicting objectives of the public sector and the private taxi firms using a bi-objective maximization approach. The taxi utilization rate and the customer wait/search time or service quality are proved to be constant along the Pareto frontier and equal to those at social optimum if the meeting functions show constant returns to scale. Extensions are made to the cases with increasing and decreasing returns to scale. 相似文献
995.
曾潮洁 《兰州交通大学学报》2005,24(2):94-97
文章在分析了高校财务管理部门面对的内外公众关系的基础上,论述了良好的公共关系环境对高校开展财务管理工作的重要意义,探讨了高校财务管理部门营造良好的公共关系环境的方法和途径. 相似文献
996.
连杆在内燃机的运行中起着非常重要的作用,其工作环境要求其具有很高的强度和可靠性.运用ANSYS软件对12V180内燃机连杆进行强度分析,确定其在危险工况下的应力分布,找出强度的薄弱环节,为连杆结构的改进和设计提供理论依据. 相似文献
997.
A new wavelength reservation scheme is proposed to mitigate the connection setup time and minimize the reconfiguration times
of optical cross-connects (OXCs) for WDM optical networks in this study. In this scheme, we consider the reconfiguration information
of switch fabrics in the signaling protocol, which is designated as the signaling with switch fabric status (SWFS). Distributed
reservation algorithms will reserve the wavelength with minimum of reconfiguration times of OXCs along the route. Simulation
results indicate that the proposed schemes with switch fabrics status have shorter setup time, lower switching ratio as well
as better blocking performance than those of the traditional classic schemes. Moreover, the proposed schemes with SWFS significantly
reduce the number of switch fabrics that need to be reconfigured.
Foundation item: the National Natural Science Foundation of China (Nos. 60632010 and 60572029) and the National High Technology Research and
Development Program (863) of China (No. 2006AA01Z251) 相似文献
998.
互通式立交设计是整个高速公路设计中的重要一环,立交设计的成败直接影响到全线高速公路的服务水平和运营安全,因此对其设计过程进行改进与完善十分必要。 相似文献
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