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81.
Investigated is the coupled response of a tension leg platform (TLP) for random waves. Inferred are the mass matrix, coupling stiffness matrix, damping matrix in the vibration differential equation and external load of TLP in moving coordinating system. Infinitesimal method is applied to divide columns and pontoons into small parts. Time domain motion equation is solved by Runge-Kutta integration scheme. Jonswap spectrum is simulated in the random wave, current is simulated by linear interpolation, and NPD spectrum is applied as wind spectrum. The Monte Carlo method is used to simulate random waves and fluctuated wind. Coupling dynamic response, change of tendon tension and riser tension in different sea conditions are analyzed by power spectral density (PSD). The influence of approach angle on dynamic response of TLP and tendon tension is compared. 相似文献
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WANG Jinrong HU Yongbin HUANG Shufeng CHEN Bin YE Yuansheng LUO Xiaohua Lv Xinbiao 《《地质学报》英文版》2017,91(Z1):289-290
<正>1 Introduction Rare-metal granites are widely distributed in South China.The Daping porphyritic granitic Ta-Nb deposit,located in the Yongding area of south Fujian province,South China,is a large rare-metal deposit recently discovered.Few studies have been made of its petrology,mineralogy,geochemistry,chronology and metallogeny.In recent years,several exploratory drillings have been done in this deposit.These drilling holes,from 380 to 600 相似文献
84.
HCHO is ubiquitous and important chemical constitutes in the troposphere. The concentrations of the HCHO (aq) in the rainwater were measured in the Guiyang city, southeastern of China from May 2006 to April 2007 and 153 discrete samples were collected. Rainwater (N = 151) HCHO (aq) concentrations ranged from lower than method detection limit (MDL) to 40.2 µmol/L with a volume weighted mean value of 7.4 ± 8.8 µmol/L. The strong correlations between HCHO (aq) and HCOO? (r = 0.69, n = 137), HCHO (aq) and nss‐ (r = 0.74, n = 137), HCHO (aq) and (r = 0.67, n = 137), HCHO (aq) and (r = 0.74, n = 133) suggest the significant influence of the anthropogenic input for the HCHO (aq) levels. The concentration levels of rainwater HCHO (aq) was inversely proportional to the amount of rainfall, indicating the below‐cloud process is the most important mechanism for rainwater HCHO (aq) scavenging processes. More than 70% of the HCHO (aq) wet deposition took place during the early stage of the rainfall. According to the air mass back‐trajectory analysis, the rainwater with industrial back‐trajectories coming from the north had the highest levels of HCHO (aq) while the rainwater with the green‐covered or marine back‐trajectories from the southeast had the lowest concentrations, and this indicate the HCHO (aq) originated from urban or industrial regions served as an important source of the rainwater. The annual HCHO (aq) wet deposition flux was calculated as 6.96 mmol/m2 per year and the total deposition flux was estimated as 24.35 mmol/m2 per year, 71.4% of which was dominated by dry deposition. 相似文献
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风沙流研究越来越受到人们的重视,其中风沙流通量廓线研究起着重要作用。本文总结了3种典型地表(流沙地表、草方格地表、戈壁地表)风沙流通量廓线研究现状及存在问题。由于研究方法、研究区域及集沙效率的不同,风沙流通量廓线函数有指数函数、对数函数、幂函数、分段函数等多种,同一问题不同函数模拟结果差异可达到3倍,难以应用于实际。根据研究中存在的问题,提出风沙流通量廓线研究发展趋势。 相似文献
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破坏性地震应急信息处置研究现状简述 总被引:1,自引:0,他引:1
结合地震应急实例,分析了对破坏性地震应急信息处置的认识,并对国内外有关方面的研究现状进行了简要介绍. 相似文献
88.
Ying Zhang Zhenbo Lv Bo Guan Yuanjin Liu Fan Li Shaowen Li Yuanqing Ma Junbao Yu Yunzhao Li 《洁净——土壤、空气、水》2013,41(10):1027-1034
Laizhou Bay, located in the northwest of Shandong Peninsula, has complex transitional environments between terrestrial and marine ecosystems. In the present study, a total of 122, 131, and 139 species were collected in spring, summer, and autumn 2011, respectively. Species constitutions of macrobenthos were grouped into four phyla, of which annelida were the most abundant phylum, the average biomass proportion of echinodermata was the lowest, and the proportion of important species for mollusca was the highest. The structure of the macrobenthic community showed significant differences between sites, and greater divergence was observed between the third site (S03) and other stations. The ABC plots showed that the biomass curve lay below the abundance curve, and the W‐statistic value was negative. The result of the BOPA index showed that two stations had moderate ecological status in spring and that there were two heavily polluted sites and one moderately polluted site in summer. The BIO‐ENV analyses indicated that the grain‐size fractions together with trace metals (Hg, Pb, Zn, Cu, and Cr) could be considered as the major environmental variables influencing the macrobenthic patterns. The results together demonstrated that the macrobenthic communities in Laizhou Bay were negatively affected, perhaps by the tremendous impact of heavy metals in the sediments. 相似文献
89.
Cheng-Bang An Shi-Chen Tao Jiaju Zhao Fa-Hu Chen Yanbin Lv Weimiao Dong Hu Li Yongtao Zhao Ming Jin Zongli Wang 《Journal of Paleolimnology》2013,49(2):145-154
Surface and fossil pollen samples were collected to reconstruct the vegetation and environment since 30.7 cal ka BP in the Lake Balikun Basin, northwest China. This record demonstrates that the region was occupied by four vegetation communities during the interval 30.7–9.0 cal ka BP, including desert steppe (30.7–25.1 cal ka BP), Amaranthaceae-Asteraceae desert (25.1–17.7 cal ka BP), Amaranthaceae-Artemisia-Asteraceae desert (17.7–12.8 cal ka BP) and Amaranthaceae desert (12.8–9.0 cal ka BP), corresponding to relatively humid, the coldest and driest, cold and dry, and colder and drier conditions, respectively. The reconstructions of vegetation and environmental changes around Lake Balikun do not support the interpretation of an extremely humid LGM in Central Asia, challenging the cold-moist (glacial), warm-dry (interglacial) pattern of late Quaternary environmental change in Central Asia. The Last Glacial Maximum was cold and dry, and similarly harsh conditions continued into the early Holocene. 相似文献
90.