接地变压器保护整定

分析了中性点经小电阻接地系统发生单相接地时的电流分布,对曲折型接地变压器保护与电缆馈出线零序过流保护的配合问题进行了探讨,并阐述了个人的观点。     

TTB or not TTB, that is the question: a review and analysis of the empirical literature on travel time (and money) budgets

This paper summarizes and analyses findings from more than two dozen aggregate and disaggregate studies of travel time (and sometimes money) expenditures, exploring the question of the existence of a constant travel time budget. We conclude (with prior researchers) that travel time expenditures are not constant except, perhaps, at the most aggregate level. Nevertheless, individuals’ travel time expenditures do show patterns that can be partly explained by measurable characteristics. Travel time expenditure is strongly related to individual and household characteristics (e.g., income level, gender, employment status, and car ownership), attributes of activities at the destination (e.g., activity group and activity duration), and characteristics of residential areas (e.g., density, spatial structure, and level of service). To the extent that travel time expenditures are constant at the aggregate level, the underlying mechanisms explaining that regularity are not well understood. Consequently, further research into explaining travel time and money expenditure patterns is justified.     

Numerical method for simulating tire rolling noise by the concept of periodically exciting contact force

For the numerical simulation of tire rolling noise, an important subject is the extraction of normal velocity data of the tire surface that are essential for the acoustic analysis. In the current study, a concept of periodically exciting contact force is introduced to effectively extract the tire normal velocity data. The ground contact pressure within contact patch that is obtained by the static tire contact analysis is periodically applied to the whole tread surface of stationary tire. The periodically exciting contact forces are sequentially applied with a time delay corresponding to the tire rolling speed. The tire vibration is analyzed by the mode superposition in the frequency domain, and the acoustic analysis is performed by commercial BEM code. The proposed method is illustrated through the numerical experiment of 3-D smooth tire model and verified from the comparison with experiment, and furthermore the acoustical responses are investigated to the tire rolling speed.     

对在基坑围护工程设计中应用价值工程理论的探讨

针对目前基坑围护工程设计中的成本控制问题，介绍了通过应用价值工程理论控制基坑围护成本的方法。通过探索，把价值工程理论和方法运用在整个基坑围护设计过程中，使设计更加安全可靠、经济合理，并能有效控制和降低成本。     

解放思想 改变观念 努力打造行政执法一面旗

行政执法一面旗建设是依法治国方略实施和经济社会发展的必然要求，是海事事业可持续发展的必然保障。一面旗建设从抓根本、打基础、完善基本制度入手，在海事事业发展成果的基础上，突出强调了海事队伍综合素质的进一步提高和社会形象的进一步提升，是海事工作经验的总结和升华，是“一家人一盘棋”理念的继承和发展，是提高“三个服务”能力和水平的重要举措。     

“地铁+物业”综合开发初探

"地铁+物业"综合开发是补贴轨道交通运营亏损,解决其建设融资难的重要途径。研究"地铁+物业"综合开发模式,是一项需要迫切解决的重要课题。结合广州市的开发实践,提出了"地铁+物业"综合开发的建议。     

汽油机活塞温度场有限元分析

文章论述了活塞热分析的理论基础,建立了活塞三维有限元模型,通过理论计算某发动机活塞热边界条件,对其进行温度场分析计算,得到活塞的三维温度场分布特征,为活塞的结构改进和优化提供了依据。     

aPLI冲击器动态标定方法研究

随着国内汽车安全领域的不断发展,汽车行人保护的概念逐渐被消费者了解,并受到了越来越多的关注,一种新型的aPLI冲击器开始参与试验评估。该冲击器与现有柔性腿型冲击器有较大区别,标定方法及评价区间也有不同之处,更高精确度的标定能够更好的反应冲击器的真实状况,但是国内使用该冲击器的经验不够丰富,本文通过拆解介绍了aPLI冲击器的结构,展示了其工作原理,并结合标准要求与试验室环境得出了一套基于现有条件对aPLI冲击器进行标定的实操方法,结合标定结果与参考标准确认试验的有效性,通过多次标定进行数据分析,对一些试验中的注意事项进行总结,为其他试验室开展该冲击器标定试验提供参考。     

Feasibility study for the application of air inflated membrane structure in China National Stadium

China National Stadium, also known as “Bird’s Nest”, is the main stadium of the 29th Olympic Games in Beijing in 2008, which has successfully held not only the Opening and the Closing ceremonies but also the track and field events. A new problem of rain preventing is brought out to improve the utilization of the Bird’s Nest after the Olympic Games. The scheme of installing an air inflated membrane at the opening of the steel structure is proposed in this paper to solve the rainproof problem of the Bird’s Nest. The form-finding and mechanical analyses of the air inflated membrane are carried out. Comparison between the mechanical performance and dynamical character before and after installing the air inflated membrane structure is given. To verify the analysis results, based on the practical structure of the Bird’s Nest, a test of a 1:20 model membrane is worked out.