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新浪科技讯 北京时间11月3日消息,据美国宇航局太空网报道,专家们表示,人类历史上的第一次地外采矿活动,可能会从月球上开始,这是由于它含有大量相对比较容易获得的水冰。这是在询问一个由科学家和工程师组成的座谈小组:人类首先应该到地球以外的什么地方进行采矿时,他们大多数人给出的看法。 相似文献
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北京时间2010年1月13日5时53分(当地时间2010年1月12日16时53分),加勒比岛国海地发生7.3级地震(震中18.5°N,72.5°W),首都太子港及全国大部分地区受灾情况严重,大片建筑物倒塌,死亡人数不断攀升。这场地震是海地自1770年以来遭遇的最强地震, 相似文献
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2005年8月16日当地时间上午11点46分左右(北京时间10点46分),在日本东北地区官城县发生了里氏7.2级地震。震中位于官城县南部80km的海域,震源距离海底42km。地震发生后,首都东京震感强烈,东北地区的新干线高速铁路系统、部分铁路干线以及仙台市地铁系统均中止运行。 相似文献
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Objective Analysis of Circulation Extremes During the 21 July 2012 Torrential Rain in Beijing 总被引:1,自引:0,他引:1
ZHAO Yangyang ZHANG Qinghong DU Yu JIANG Man ZHANG Jiping 《Acta Meteorologica Sinica》2013,27(5):626-635
It has been reported that the heaviest rain event since 1951 hit Beijing on 21 July 2012 (henceforth referred to as the 721 case).The frequency and extreme attributes of the large-scale circulation patterns observed during the 721 case are explored by using obliquely rotated T-mode principle component analysis (PCA) and reanalysis data from NCEP/NCAR.The occurrence frequency of the 721-type circulation during the summers of 1951-2012 is 10.9%,while the frequency of torrential rain under this type of circulation is 4.51%.Relative to other rainstorms with similar large-scale circulations during the study period,the 721 case is characterized by a more westward extension of the subtropical high over the western North Pacific,a stronger low-level jet in the lower troposphere over the south of Beijing,a larger amount of ambient precipitable water,and a stronger vertical wind shear over Beijing.Among the 621 days with the 721-type circulation during the study period,the 721 case ranks the 54th in terms of the 925-hPa low-level jet south of Beijing,the 209th in terms of the local vertical wind shear,and the 8th in terms of the local precipitable water.The 721 case is particularly extreme with respect to the 925-hPa low-level jet south of Beijing and local precipitable water.Cases with similar circulations and equal or greater values of the 925-hPa low-level jet south of Beijing and local precipitable water have occurred thrice during the summers of 1951-2012 (i.e.,once every 21 years). 相似文献