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针对低烈度区砌体结构房屋抗震的需要,本文提出利用纤维砂浆带加固砌体墙的一种廉价抗震方案。运用有限元分析软件Ansys10.0进行数值模拟分析,探讨这种加固方案的可行性,并在此基础上进行试验研究。通过纤维砂浆带加固砌体墙片在低周反复荷载作用下的试验,对墙片的破坏特征、裂缝的发展过程、滞回特性、结构延性等技术指标进行对比分析,结果表明,采用纤维砂浆带加固砌体墙有助于提高墙体的开裂荷载,增加结构的延性,改善墙体的抗震性能。 相似文献
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基于浮动薄板理论,研究瞬变电磁场层状介质中视纵向电导的计算方法,利用遗传算法代替常用的阻尼最小二乘法来获取关键参数。进行“烟圈”反演计算,并分别采用3层H (K)型和4层HK型地电模型对比视纵向电导曲线和电阻率—深度曲线。结果表明,“烟圈”反演具有不需初始模型、计算简便等优点,在定性反演方面,视纵向电导解释方法可以更准确地划分电性层,且能够比较直观地体现电性变化趋势。 相似文献
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Highly restricted gene flow between disjunct populations of the skunk clownfish (Amphiprion akallopisos) in the Indian Ocean 下载免费PDF全文
The skunk clownfish (Amphiprion akallopisos) has a disjunct distribution, occurring in the Eastern Indian Ocean (EIO) and the Western Indian Ocean (WIO), separated by several thousands of kilometres. Information on connectivity of marine species is very important for the correct spacing of marine protected areas, a powerful instrument for the protection of coral reefs. The population genetic structure of A. akallopisos was analysed in order to investigate connectivity amongst populations and to explain the disjunct distribution of the species. A fragment of the mitochondrial control region was used to investigate the genetic population structure. Fin clips were collected from 263 individuals at 14 sites in the WIO and three sites in the EIO. The obtained DNA sequences were used to calculate genetic diversity, evaluate demographic history and to construct a haplotype network. An analysis of molecular variance (AMOVA) was conducted to evaluate the significance of the observed genetic population structure. None of the identified 69 haplotypes was shared between the WIO and EIO. Haplotype as well as nucleotide diversity was considerably higher in the EIO than in the WIO. Significant genetic population structure was revealed by an AMOVA with an overall φst‐value of 0.28 (P < 0.001) in the Indian Ocean. The overall AMOVA (φst = ?0.00652) was not significant in the EIO, but was significant in the WIO (φst = 0.016; P < 0.01). Demographic analysis indicated population expansion in the EIO and WIO. Population genetic analysis revealed highly restricted gene flow between the EIO and WIO. Genetic diversity was much higher in the EIO than in the WIO, suggesting that the EIO is the geographical origin of the species. Given the large distance between the disjunct populations and the short pelagic larval duration, long‐distance dispersal is rather unlikely. A stepping stone model involving islands in the Central Indian Ocean is a more likely scenario for colonization of the WIO. 相似文献
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Along with the economic development,large tunnels need to be constructed in many high mountains or complex structure regions,and the design and construction of detailed tunnel exploration become particularly important.Transient electromagnetic method (TEM) uses a non-grounded loop or an electrode to send a primary electromagnetic pulse into the ground,and observes spatial and temporal distribution of secondary electromagnetic field,which is widely applied in mineral resource exploration,engineering geology,etc.The application of TEM in the tunnel construction of Kaiyuan Temple is researched in this study.The smoke loop inversion is adopted for inverting the transient electromagnetic data.The drilling data and high density resistivity method data are combined for comparison.The obtained inversion result greatly coincides with the actual conditions.Therefore,the geophysical prospecting basis can be provided for the division of stratum,delineation of geologi-cal structure,and design and construction of tunnel pavement.By virtue of TEM,drilling data and high density resistivity method,the tunnel construction of Kaiyuan Temple has obtained satisfactory results. 相似文献
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