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由于高精度质谱计的使用范围日益扩大及其可靠性的不断增长,使一些地质问题的研究方法有了新的重大发展。这些方法的重要性日益增加,目前已为质谱计的应用提供了主耍的场所。在地球化学中有三个经常碰到的问题,即放射性测定年龄、研究非放射成因的同位素丰度变异及分析微量元素,它们都需要相当专门性质的质谱技术。例如,在地质年代学研究中使用的仪器,要求在小质量范围内,重复测量结果的偏差不大于千分之几;而许多丰度变异的研究,要求偏差要在万分之一左右。本文从较为专门 相似文献
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Earthquake simulator tests of a 1/6-scale nine-story reinforced concrete frame-wall model are described in the paper. The test results and associated numerical simulation are summarized and discussed. Based on the test data, a relationship between maximum inter-story drift and damage state is established. Equations of variation of structural characteristics (natural frequency and equivalent stiffness) with overall drifts are derived by data fitting, which can be used to estimate structural damage state if structural characteristics can be measured. A comparison of the analytical and experimental results show that both the commonly used equivalent beam and fiber element models can simulate the nonlinear seismic response of structures very well. Finally, conclusions associated with seismic design and damage evaluation of RC structures are presented. 相似文献
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砌体加固方案优选方法对实际工程遴选方案具有重要意义。为此建立了组合赋权法与TOPSIS法相结合的砌体结构加固方案优选方法,引入加固效费比模型,以效费比值为定量指标,以施工工期、施工技术、效果、整体效应4个因素作为定性指标,建立砌体结构抗震加固优选方案指标体系。以某教学楼为例,运用G1-COWA组合赋权法与TOPSIS法,求出该结构最佳加固方案为板墙加固方案。结果表明:所提出的优选方法具有一定的实用性和有效性,也适用于一般砌体加固改造工程;优选方法能根据既有结构的基本信息,科学便捷地决策出最佳方案,为砌体结构的加固设计实施提供更科学的技术支撑。 相似文献
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