Wind tunnel simulation experiment and investigation on the electrification of sandstorms

~~Wind tunnel simulation experiment and investigation on the electrification of sandstorms~~     

江西东坪石英脉型黑钨矿矿床地质特征、控矿因素及找矿标志

东坪钨矿床是近年在赣北地区新发现的首个超大型石英脉型黑钨矿矿床,位于长江中下游成矿带幕阜山地区东坪-香炉山钨矿找矿远景区东部。矿床赋矿层位为新元古代双桥山群安乐林组浅变质岩系,北东向断裂及其两侧的次级裂隙为区内主要控矿构造、容矿构造,隐伏的燕山晚期黑云母二长花岗岩为成矿岩体,与区内钨多金属成矿关系密切的为石英脉状硅化;两个矿带的钨矿体均产于成矿岩体外接触带,呈现了石英脉型黑钨矿矿床典型的"五层楼"分带特征,矿石工业类型主要为黑钨矿矿石;明确了构造和岩浆岩等主要控矿因素;总结出地表微细裂隙云英岩化-黄铁矿化蚀变带、含硫化物石英细脉带、石英脉、重砂及地球化学异常为区内主要找矿标志。     

百余年的ENSO事件与北京汛期旱涝的统计关系

利用王绍武等人最近对近百年ＥＮＳＯ事件及强度的研究结果,对ＥＮＳＯ事件与北京汛期相当暴雨日数的统计关系进行分析,表明,ＥＮＳＯ事件与北京沁期旱涝存在较复杂的统计关系,ＥＮＳＯ事件的性质,强度,起始季节和持续时间长短等与汛期旱涝的对应关系是复杂的。根据１８６７－１９９８年的ＥＮＳＯ事件和同期北京汛期相当暴雨日数资料,给出一些统计结果。     

Early Cenozoic paleontological assemblages and provenance evolution of the Lishui Sag,East China Sea

The East China Sea Shelf Basin generated a series of back-arc basins with thick successions of marine- and terrestrial-facies sediments during Cenozoic. It is enriched with abundant oil and gas resources and is of great significance to the petroleum exploration undertakings. Therein, the Lishui Sag formed fan delta, fluvial delta and littoral-to-neritic facies sediments during Paleocene–Eocene, and the research on its sedimentary environment and sediment source was controversial. This study analyzed the paleontological combination characteristics, and conducted a source-to-sink comparative analysis to restore the sedimentary environment and provenance evolution of the Lishui Sag during Paleocene–Eocene based on the integration of detrital zircon U-Pb age spectra patterns with paleontological assemblages. The results indicated that Lishui Sag was dominated by littoral and neritic-facies environment during time corroborated by large abundance of foraminifera, calcareous nannofossils and dinoflagellates. Chronological analysis of detrital zircon U-Pb revealed that there were significant differences in sediment sources between the east and west area of the Lishui Sag. The western area was featured by deeper water depths in the Paleocene–Eocene, and the sediment was characterized by a single Yanshanian peak of zircon U-Pb age spectra, and mainly influenced from Yanshanian magmatic rocks of South China Coast and the surrounding paleo-uplifts. However, its eastern area partly showed Indosinian populations. In particular, the upper Eocene Wenzhou sediments were featured by increasingly plentiful Precambrian zircons in addition to the large Indosinian-Yanshanian peaks, indicating a possible impact from the Yushan Low Uplift to the east. Therefore, it is likely that the eastern Lishui Sag generated large river systems as well as deltas during time. Due to the Yuquan Movement, the Lishui Sag experienced uplifting and exhumation in the late stage of the late Eocene and was not deposited with sediments until Miocene. Featured by transitional-facies depositions of Paleocene–Eocene, the Lishui Sag thus beared significant potential for source rock and oil-gas reservoir accumulation.     

汶川地震山脚震害特征及机理分析1

汶川地震和以往地震现场震害调查表明,局部场地地形对震害的影响明显,其中,山脚房屋震害程度明显低于山顶和水平地表土层场地.针对这一震害特征,本文以汶川主震的地形效应观测强震动记录和人工爆破山体地形地震动观测记录为基础,通过数据分析,结合动力集中质量中心差分有限元法进行数值模拟分析,进一步揭示了山脚房屋震害轻微的特征不仅与其所在场地条件良好有关,更与山脚所处山体底部的几何位置直接相关.     

单元畸变对动力有限元方法计算精度的影响

在有限元分析中,由于求解区域或边界的不规则,有限单元的划分会产生畸变单元。本文通过数值试验分析了有限单元畸变对动力有限元计算精度的影响,结果表明:长宽比畸变对动力有限元计算精度没有影响;当斜交角不小于30°时,斜交角对动力有限元计算精度的影响可忽略;锥度对动力有限元计算精度有影响,锥度越大,锥度对动力有限元计算精度的影响越大。     

Spatio-temporal characteristics of aftershocks and seismogenic structure of the 2011 MW9.0 Tohoku earthquake,Japan

The Tohoku megathrust earthquake, which occurred on March 11, 2011 and had an epicenter that was 70 km east of Tohoku, Japan, resulted in an estimated ten's of billions of dollars in damage and a death toll of more than 15 thousand lives, yet few studies have documented key spatio-temporal seismogenic characteristics. Specifically, the temporal decay of aftershock activity, the number of strong aftershocks (with magnitudes greater than or equal to 7.0), the magnitude of the greatest aftershock, and area of possible aftershocks. Forecasted results from this study are based on Gutenberg-Richter's relation, Bath's law, Omori's law, and Well's relation of rupture scale utilizing the magnitude and statistical parameters of earthquakes in USA and China (Landers, Northridge, Hector Mine, San Simeon and Wenchuan earthquakes). The number of strong aftershocks, the parameters of Gutenberg-Richter's relation, and the modified form of Omori's law are confirmed based on the aftershock sequence data from the M_W9.0 Tohoku earthquake. Moreover, for a large earthquake, the seismogenic structure could be a fault, a fault system, or an intersection of several faults. The seismogenic structure of the earthquake suggests that the event occurred on a thrust fault near the Japan trench within the overriding plate that subsequently triggered three or more active faults producing large aftershocks.     

四川熊蜂蜜粉源植物选择偏好

山地是熊蜂最重要的栖息地,而熊蜂是山地环境质量的重要指示生物,被广泛应用于指示人类活动对生态质量的影响.2002～2007年在四川西部4种生境中随机选择地点采集野生熊蜂,记录熊蜂物种及其访花植物,分析熊蜂对蜜粉源植物选择偏好.共采集熊蜂3 048只,属于15个亚属的47种.分析表明,熊蜂偏好选择一种或少数几种蜜粉源植物,同一种熊蜂在不同生境中对蜜粉源植物选择偏好不同,同一种熊蜂在同一生境中可偏好选择多种蜜粉源植物.最后讨论了熊蜂对蜜粉源植物选择偏好的生态意义.     

钱塘江古海塘塘基防渗加固现场试验研究

目前仍然坚守在防洪御潮第一线的钱塘江明清古海塘,由于年代久远,部分塘段的塘趾部位存在流土现象,因此,选用合理且不破坏古海塘风貌的塘基防渗加固方案来保护古海塘十分必要。以浙江海宁某明清古海塘试验段为依托,通过现场试验,对比研究了4种塘基防渗加固保护方案,通过有限元分析、现场渗透试验、加固后开挖检验、施工期对古海塘的影响监测等手段,分析总结了各加固方案的优缺点,得到了机械适当改制后的“塘趾旋喷注浆”方案为优选方案的结论,研究成果对下一步钱塘江临江古海塘保护工程的塘基防渗加固方案选取具有重要参考价值。     

汶川M_S8.0地震的强余震流动观测

2008年5月12日汶川大地震发生后,中国地震局迅速组织开展了强余震流动观测,沿龙门山断裂附近布设了59台强震动仪器.在观测期间发生了万余次余震,流动观测台网获得了2000多组3分量的强余震记录.本文介绍了流动观测台布设的技术方法与关键步骤,初步处理了2008年5月25日青川6.4级最大余震的地震动记录,并分析了此次地震动衰减特征.此次流动观测充分表明,在大地震发生后,及时有效地开展强震动流动观测是十分必要的,其获得的余震地震动记录可为进一步的科研工作提供宝贵的基础资料.