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综合处理应用高液限土进行公路建设,可以避免过大的增加工程造价及保证路基的强度和稳定性,结合广西等地区在这方面的实践情况,介绍了利用隔离排水、掺粗粒土、土石混填等方法综合改良高液限土进行路基填筑的经验,分析探讨其可行性,为今后相似情况下的设计或施工提供一定的借鉴。 相似文献
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Assessing the technical efficiency, service effectiveness, and technical effectiveness of the world’s railways through NDEA analysis 总被引:1,自引:0,他引:1
This paper presents an approach to include both the unstorable feature of transportation service and the technological differences within railway companies in efficiency and effectiveness measurements. We explore efficiency and effectiveness for a group of 40 global railways in the year 2002, using traditional data development analysis (TDEA) and network data development analysis (NDEA). Comparing the results obtained from the NDEA model with those from the TDEA indicate that performance measures are quite different in terms of the magnitude, and even using different DEA type models to evaluate railway system performance does not distort the ranking of their performance. We also analyze the inter-related effects among three performance measures, finding that transportation service characteristics have positive effects on the evaluation of performance. Generally speaking, the NDEA model provides deeper insight regarding the sources of inefficiency and process-specific guidance to railway managers so as to help them improve their railway’s performance. 相似文献
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To predict the attitude of satellite during the whole deployment process and evaluate the lockingimpact, a numerical flexible model of a certain satellite associated with four flexible honeycomb solar panelswas established. The flexible solar panel was modeled by the finite element analysis (FEA), and the motionequations were derived by Lagrangian formulation. The locking process was based on the method of Hertziancontact, which enables one to predict the locking impact on the satellite and the subsequent oscillation of solarpanels. The results reveal that locking operation has great impact on the attitude of the satelhte, and theangular acceleration of satellite reaches 22.03 °/s2 at the locking moment; the flexible solar panels model isfeasible to predict the accurate response of the satelhte during deployment and the oscillation of solar panels;the instantly impulsive force occurred during locking process is about 1.5 kN and the changing time is nearly0.32 s. It provides an effective approach to present the flexible solar panels' deployment process and evaluatethe locking impact. 相似文献
779.
A multi-try counter-meshing gears (CMG) discrimination device based on micro electromechani-cal system (MEMS) technology was designed for some specified information fields. The discrimination deviceconsists of two groups of metal CMG, two pawl/ratchet mechanisms, two driving micromotors and two re-setting micromotors, which make the CMG withdraw by raising the pawls. The energy-coupling element isa photoelectric sensor with a circular plate which is notched. Micromotor is fabricated using the ultravioletLiGA (UV-LiGA) fabrication process and precision mechanical engineering. The discrimination device has thefunction which can automatically reset, with the correct resetting code, it can be tried another times. 相似文献
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提高混凝土自身的耐久性能,有效地阻止腐蚀性介质的渗入,是解决混凝土结构耐久性的前提和基础。混凝土的耐久性主要取决于混凝土的材料组成,其中水灰比、水泥质量、强度等级均对耐久性有较大影响影响。因此,采取合理的结构设计和配筋,选用合格的原材料,设计最佳的保护层厚度及有效地控制混凝土结构开裂的措施,都将有效地提高混凝土结构的耐久性。 相似文献