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排序方式: 共有3114条查询结果,搜索用时 156 毫秒
931.
王盼 《汽车实用技术》2021,46(8):142-143,152
采用红外谱图分析及扫描电镜分析等方法,分析了PC/ABS基材电镀产品表面漏镀形成的原因,并通过反复验证找出了合理的解决方案。结果显示,发生漏镀的位置PC含量较高,橡胶B(丁二烯)含量较低,造成表面粗化不良,通过优化粗化浓度能有效减少漏镀不良的产生。  相似文献   
932.
潘芳芳 《中国水运》2006,6(4):145-146
介绍了内河船员现状,通过对船员基本情况、存在问题的分析,提出加强对船员教育、管理,切实提高船员的业务素质,更好地发挥其在实现水运强省工程中的积极作用,应是行业管理部门的当务之急  相似文献   
933.
An accurate, efficient algorithm for solving free surface flows around ship hulls is described. Accuracy is achieved using a compressive advection discretization which maintains a sharp free surface interface representation without relying on a small time step. Efficiency is obtained using a solution algorithm which implicitly couples velocity, pressure, and volume fractions. The algorithm has been implemented in a computational fluid dynamics code called CFX and is validated by means of a comparisonwith experimental data of benchmark cases in both steady and transient conditions.  相似文献   
934.
This paper examines how conversion of automobile trips of less than 3 miles to other transportation modes reduces emissions. Short trips contribute disproportionately to emissions because of cold starts. An analysis is conducted of short-trip behavior across the US using the 1995 Nationwide Personal Transportation Survey. The data is used to develop likely scenarios of mode conversions for short trips, which are then applied to estimate emission savings using MOBILE6 cold start and running emission factors for volatile organic compounds, nitrogen oxides, carbon monoxide, and carbon dioxide. The results suggest that reducing short auto trips would modestly reduce mobile source air pollution, but emission reductions are high compared to most federally-funded surface transportation interventions aimed at improving air quality. Enhanced the community pedestrian environment to encourage short trip mode conversion also produces co-benefits such as increased physical activity and subsequent reductions in chronic diseases.  相似文献   
935.
Motorization in vehicles is expanding rapidly for fuel efficiency, customer comfort, convenience, and safety features. These new electric loads represent an increase in the required electric power. This has generated interest in new, higher power systems such as the 42V Power Net. The electro-hydraulic power steering (EHPS) system is one of these systems. This paper presents the development of the electric motor-driven pump unit for the EHPS system using a 42V power-Net. The interior type permanent magnet synchronous motor (IPMSM) can be applied to this system with more power density per volume for compactness of the EHPS. In order to improve the system, the IPMSM and its control method was optimized for improved torque characteristics and electric power consumption. The performances of both the pump unit and the IPMSM have been verified by experimental results. Finally, all in one type the electric motor-driven pump unit are developed from the experiment verification.  相似文献   
936.
One of the most difficult and expensive tasks in making noise pollution maps is the collection and processing of the data needed to create acoustic models. In the case of road traffic noise maps, obtaining speed data for light and heavy vehicles a problem that has usually been avoided by using a road’s speed limit or by making assumptions based on experience from similar road types. Here global positioning systems-based techniques are applied for acquiring vehicle speed data and adapted to fulfill the requirements of noise prediction models.  相似文献   
937.
文章基于大型通用有限元软件ANSYS提出了一种大跨度桥梁抖振时域实用分析方法。在该方法中,自激力是通过向有限元模型中添加气动刚度和气动阻尼单元的方式来实现的。计算了独塔斜拉桥在不同风速和攻角下的抖振位移响应,与传统频域分析结果的比较表明了该方法的可行性。  相似文献   
938.
通过对2起机车带电闯电分相变电所跳闸报告的分析,探讨了变电所馈线保护的整定方案,提出了接触网相间短路情况下杜绝馈线保护拒动的措施.  相似文献   
939.
This paper addresses the relationship between land use, destination selection, and travel mode choice. Specifically, it focuses on intrazonal trips, a sub-category of trip making where both trip origin and trip destination are contained in the same geographic unit of analysis, using data from the 1994 Household Activity and Travel Diary Survey conducted by Portland Metro. Using multinomial logit and binary logistic models to measure travel mode choice and decision to internalize trips, the evidence supports the conclusions that (1) intrazonal trips characteristics suggest mode choice for these trips might be influenced by urban form, which in turn affects regional trip distribution; (2) there is a threshold effect in the ability of economic diversity/mixed use to alter travel behavior; and (3) greater emphasis to destinations within the area where an individual’s home is located needs to be given in trip distribution models.  相似文献   
940.
1 2005年物资设备工作总结 2005年物资部门干部职工紧紧围绕路局总体经营目标,全力落实物资工作"六个确保",强力推进清车核编和设备安全管理,各项工作取得了显著成果.  相似文献   
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