Silting in the Lower Courses of Tidal Sluices in China   总被引：2，自引：0，他引：2  

张金善  黄建维杨红 《中国海洋工程》2004,18(1):137-148

Serious sediment deposition often occurs after the construction of tidal sluices in snrall or medium-sized tidal muddy estuaries, so desilting or dredging is needed to meet the demands of flood diseharge, saltwater retaining, and navigation in those areas. In this paper, the problem of sediment deposition induced by construction of tidal sluices is analyzed.Different problems of silting near tidal sluices for different types of estuaries are summed up. at the same time, corresponding methods are given to solve these probleras, and a few successful examples are also given. The idea of comprehensive regulation and utilization of estuaries is put forward, and some proposals for solution of sediment deposition in this kind of estuaries are made.  相似文献   

Ultimate Strength Analysis of Offshore Jacket Platform     

Xu Bin Shen Zhonghan Research Associate 《中国海洋工程》1995,(3)

- The ultimate strength analysis of offshore jacket platforms is a research project which has been developed in recent years. With the rapid development of marine oil industry, the departments of design and IMR (Inspection, Maintenance and Repair) in the offshore engineering have attached great importance to this project. The research procedure applies to both the stress check of new design platforms and the whole safety assessment of existing platforms. In this paper, we combine the pseudo non-linear technique with the linear analysis program and successfully analyze the ultimate strength of the space frame structure subject to the concentrated load and a real jacket platform subject to the dead load and environmental load.  相似文献   

江苏溧阳叶蜡石矿物,岩石初步研究     

钟华邦 《岩石矿物学杂志》1992,11(4):332-338

本文对江苏溧阳叶蜡石矿物、岩石进行薄片鉴定、差热分析、红外光谱分析、电镜分析、X衍射分析等研究,作者认为叶蜡石矿物与叶蜡石岩石的含义不同;本区叶蜡石岩中发现有两种不同类型的叶蜡石矿物;叶蜡石矿的俗称实质上是叶蜡石岩矿床的简称。作者对叶蜡石岩进行了初步的分类。  相似文献   

Two Necessary Conditions for the Glacial-Interglacial Cycles in the Quaternary     

LI Nan  CHEN Xing  LIU Fuhong 《Acta Meteorologica Sinica》2010,24(6):657-670

Milankovitch Theory shows that glacial-interglacial cycles in the Quaternary are related to the variation of solar insolation forcing linked to the earth's astronomical parameters.However,the summer insolation at northern high latitudes,usually considered as the main external forcing for the ice age as Milankovitch pointed out,is marked by the 19- and 23-ka precession periodicities,which is not consistent with the glacial-interglacial cycles.On the other hand,recent studies indicate that the annual mean ...  相似文献   

Vertical Distribution of Momentum Exchange Coefficient and Sediment Concentration in Estuarine and Coastal Waters     

黄惠明  王义刚  闻云呈  祝慧敏 《中国海洋工程》2010,(4)

Vertical structures of momentum exchange coefficient and sediment concentration are the keys in the research on estuarine and coastal suspended sediment transport. Based on the parabolic mixing length distribution pattern,the distribution pattern of vertical momentum exchange coefficient which is suitable for estuarine and coastal waters is constructed. A comparison with steady flow and measured momentum exchange coefficient during one tidal cycle in the Menai Strait of England shows that the result of this...  相似文献   

利用浅层地震勘探探测东江老隆大桥桥址的基岩构造     

闻昆娣  王迪洁  吕伟民 《湖南地质》1998,(4)

利用浅层地震勘探对广东龙川东江老隆大桥桥址进行勘查，得到测区基岩面的起伏形态、速度分布以及断层位置。结果表明，测区为一条近南北向的断裂沉降带，桥址的中心线正好通过其中。从经济与安全的角度出发，建议老隆大桥最好能另选桥址。  相似文献   

How do Canadian media report climate change impacts on health? A newspaper review     

King  Nia  Bishop-Williams  Katherine E.  Beauchamp  Sabrina  Ford  James D.  Berrang-Ford  Lea  Cunsolo  Ashlee  Team  IHACC Research  Harper  Sherilee L. 《Climatic change》2019,152(3-4):581-596

Climatic Change - Research on climate change media coverage is growing. Few studies, however, have investigated how the media portrays climate change impacts on human health. This review,...  相似文献   

Expression responses of five cold tolerant related genes to two temperature dropping treatments in sea cucumber Apostichopus japonicus     

李成泽  常亚青  庞震国  丁君  姬南京 《中国海洋湖沼学报》2015,33(2):309-318

  相似文献   

S, C, O, H Isotope Data and Noble Gas Studies of the Maoniuping LREE Deposit, Sichuan Province, China： A Mantle Connection for Mineralization   总被引：3，自引：2，他引：1  

TIAN Shihong  DING Tiping  MAO Jingwen  LI Yanhe  YUAN Zhongxin Institute of Mineral Resources  Chinese Academy of Geological Sciences  Beijing Key Laboratory of Isotope Geology  Ministry of Land  Resources  Beijing China University of Geosci 《《地质学报》英文版》2006,80(4):540-549

The Maoniuping REE deposit, located about 22 km to the southwest of Mianning, Sichuan Province, is the second largest light REE deposit in China, subsequent to the Bayan Obo Fe-Nb-REE deposit in the Inner Mongolia Autonomous Region. Tectonically, it is located in the transitional zone between the Panxi rift and the Longmenshan-Jinpingshan orogenic zone. It is a carbonatite vein-type deposit hosted in alkaline complex rocks. The bastnaesite-barite, bastnaesite-calcite, and bastnaesite-microcline lodes are the main three types of REE ore lodes. Among these, the first lode is distributed most extensively and its REE mineralization is the strongest. Theδ34Sv-CDT values of the barites in the ore of the deposit vary in a narrow range of +5.0 to +5.1‰in the bastnaesite-calcite lode and +3.3 to +5.9‰in the bastnaesite-barite lode, showing the isotopic characteristics of magma-derived sulfur. Theδ13Cv-PDB values and theδ518OV-SMOW values in the bastnaesite-calcite lode range from -3.9 to -6.9‰and from +7.3 to +9.7‰, respectively, which fall into the range of "primary carbonatites", showing that carbon and oxygen in the ores of the Maoniuping deposit were derived mainly from a deep source. Theδ13Cv-PDB values of fluid inclusions vary from -3.0 to -5.6‰, with -3.0 to -4.0‰in the bastnaesite-calcite lode and -3.0 to -5.6‰in the bastnaesite-barite lode, which show characteristics of mantle-derived carbon. TheδDv-SMOW values of fluid inclusions range from -57 to -88‰, with -63 to -86‰in the bastnaesite-calcite lode and -57 to -88‰in the bastnaesite-barite lode, which show characteristics of mantle-derived hydrogen. Theδ18OH2OV-SMOW values vary from +7.4 to +8.6‰in the bastnaesite calcite lode, and +6.7 to +7.8‰in the bastnaesite-barite lode, almost overlapping the range of +5.5 to +9.5‰for magmatic water. The 4He content, R/Ra ratios are (13.95 to 119.58×10-6 (cm3/g)STP and 0.02 to 0.11, respectively, and 40Ar/36Ar is 313±1 to 437±2. Considering the 4He increase caused by high contents of radioactive elements, a mantle-derived fluid probably exists in the inclusions in the fluorite, calcite and bastnaesite samples. The Maoniuping deposit and its associated carbonatite-alkaline complex were formed in 40.3 to 12.2 Ma according to K-Ar and U-Pb data. All these data suggest that large quantities of mantle fluids were involved in the metallogenic process of the Maoniuping REE deposit through a fault system.  相似文献   

Decentring poverty studies: Middle class alliances and the social construction of poverty   总被引：1，自引：0，他引：1  

Victoria Lawson  with Middle Class Poverty Politics Research Group 《Singapore journal of tropical geography》2012,33(1):1-19

Editors' Note: The following is the tenth in the Singapore Journal of Tropical Geography Lecture Series. It is based on the plenary presentation of 13 April at the AAG held in Seattle in 2011. In this essay I explore relational poverty analysis to take seriously the spatially varied intersections of political‐economic, social ordering and cultural‐political processes in shaping understandings of poverty. My work as part of the Middle Class Poverty Politics Research Group employs a relational comparative methodology to theorize where, when and under what circumstances those framed as ‘middle class’ act in opposition to or in solidarity with those named as ‘poor’. Our approach focuses on the exploitative effects of capital accumulation, processes of unequal sociospatial categorization and political and discursive systems that limit or exclude the poor. Our research focuses on places experiencing capitalist crisis because intense periods of restructuring highlight material and discursive struggles over poverty. We conclude by identifying a research agenda focused on the ways in which poverty politics are constituted by the nonpoor through place and in the articulation of places with processes of political economy, governance and cultural politics.  相似文献