河口冲淡水运动理论模式及数值应用(续)——(Ⅱ)数值应用     

李镇江  李心铭 《中国海洋大学学报(自然科学版)》1993,(4)

2 计算结果和讨论2.1区域特征和参数选取 具体数值模拟在图2区域上进行。区域水平尺寸为60×80km;河口口门宽5km、深5m;计算网格间距△x=△y=2.5km。海底底形考虑图3类型。其它参数取值在后面的流函数分布图中予以说明。  相似文献   

Evidence of a variable "unsampled" pelagic fish biomass in shallow water (<20 m): the case of the Gulf of Lion     

Brehmer  P.; Guillard  J.; Guennegan  Y.; Bigot  J.L.; Liorzou  B. 《ICES Journal of Marine Science》2006,63(3):444-451

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A coastal reservoir of terrestrial resources for neanderthal populations in north‐eastern Iberia: palaeoenvironmental data inferred from the small‐vertebrate assemblage of Cova del Gegant,Sitges, Barcelona     

Juan Manuel López‐García  Hugues‐Alexandre Blain  Montserrat Sanz  Joan Daura 《第四纪科学杂志》2012,27(1):105-113

Coastal areas as reservoirs of resources for hominid groups have been widely studied in recent years. These areas combine marine with terrestrial and wetland resources and would have been optimum sites for hominids, including Neanderthals. This is the case with the Cova del Gegant, a cave that today opens directly onto the Mediterranean Sea and is located in the north‐eastern Iberian Peninsula. The geomorphological evolution of the Massis del Garraf has provided evidence that during the late Pleistocene there was a littoral platform between 8 and 13 km wide in front of the Cova del Gegant. Within this framework, the data derived from analysis of the small vertebrates and large mammals recovered from Cova del Gegant, including taxa currently absent from the Massis del Garraf, suggest that the landscape surrounding the cave provided a richer terrestrial ecosystem for Neanderthals than is available in this zone today. Analysis of the small‐vertebrate association from the cave reveals that the landscape surrounding the cave was dominated by woodland‐edge and open environments and that the climate was Mediterranean. The results have been compared with the only Iberian site with similar characteristics to the Cova del Gegant, Gorham's cave (southern Iberia, Gibraltar), revealing differences and similarities in the landscape and climate on the basis of the small‐mammal assemblages as well as the differences in the accessibility to terrestrial mammalian resources for the Neanderthal groups. The landscape and the climate were reasonably similar at the two sites, but the differences in the accessibility of resources for the Neanderthals are directly related to the location of the sites and the coastal position. Whereas the Cova del Gegant was on a route of mammal migration (between the Ebro Valley and France) suited for securing terrestrial resources, Gorham's cave is located on a small peninsula with a lower abundance of terrestrial mammal resources. This is probably why the Neanderthal groups at Gorham's cave exploited marine resources, whereas there is no evidence of marine resources having been exploited at Cova del Gegant, even though the seashore was nearby. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

现代小卫星技术在对地观测中的应用     

申家双  陈波  翟京生  凌勇 《海洋测绘》2008,28(1):75-79

小卫星因其研发周期短、体积小、功能强、使用灵活等特点,近年来其发展非常迅速。探讨了现代小卫星的基本概念和技术特点,分析了国内外小卫星的发展情况和发展趋势,最后阐述了小卫星、小卫星星座以及编队飞行在对地观测获取遥感信息中的应用前景。  相似文献   

线弹性土壤中埋设悬跨管道的弯曲和振动特性   总被引：1，自引：0，他引：1  

邢静忠  柳春图 《海洋工程》2008,26(2):78-82

利用细长梁小挠度理论,研究给出了两端埋设在线弹性土壤中的悬跨段管道和埋设段管道在自重作用下的变形和内力公式。基于静挠度公式,用能量法给出了第一阶弯曲振动的固有频率公式。讨论了不同土壤刚度条件下悬跨段管道的变形和内力特征,以及第一阶弯曲振动固有频率,并和工程上推荐使用的简支梁和两端固支梁的静动态特性进行比较。研究表明在跨度大、土壤刚度大、管道弯曲刚度较小时无量纲土壤刚度系数较大,埋设段管道对悬跨段管道的刚度约束比较大,悬跨段管道可以近似按两端固支梁模型来模拟;反之,只有在土壤刚度系数较小的几个参数点上,悬跨管道的静动力特性等价于简支梁模型。  相似文献   

中国城镇人口“镇化”发展的时空分异   总被引：2，自引：0，他引：2  

刘盛和  王雪芹  戚伟 《地理研究》2019,38(1):85-101

将中国人口城镇化细分为城镇人口“镇化”与“城化”,采用“镇化水平”和“镇化贡献率”两个指标,从不同空间尺度及主体功能区视角,系统分析1982-2015年中国城镇人口镇化发展的时空分异及影响因素。主要结论包括：① 中国的城镇人口“镇化水平”和“镇化贡献率”在不断提升。2015年镇化水平为41.8%,2010-2015年期间镇化贡献率为55.1%。② 中国城镇人口镇化呈现显著的时空分异特征。镇化主导型县市主要分布在中西部地区,占全国国土面积的70%以上;城化主导型县市主要集中分布在沿海城市群地区,在全国国土面积中所占比例较小。③ 展望未来,中国城镇人口的镇化贡献率和镇化水平将稳中趋缓,应加强探索出基于主体功能区域分异的差异化小城镇发展模式。  相似文献   

Planning regional development: Promoting small settlements in a trans-frontier situation     

Erika Nagy  David Turnock 《GeoJournal》2000,50(2-3):255-271

Under communism local authorities tended to be largely passive bystanders in a regional development process which emerged through the central planning process through the spatial allocations of investment by government ministries. Attention was given to physical planning, but comparatively little material entered the public domain on location policy and spatial priorities generally, apart from the objective of greater equality between regions and a commitment to backward areas generally. Now that much investment is down to private enterprise and government has become more decentralised and accountable, there is a need for concepts and strategies to coordinate public sector investment and provide guidelines for the evaluation of private development proposals. At the same time, there is an open competition for investment which requires communities to promote themselves in terms of their identity and development potential. This paper offers an overview by taking two countries - Hungary and Romania - where progress can be compared and where the focus can be placed on a common frontier which is diverting attention from conventional regional planning to cross-border cooperation. In both contexts however, attention is given to the ways in which planning can divert investment away from the main centres to the peripheral areas, including action to strengthen the role of small towns and also to improve cohesion among functionally-related groups of settlements and communes. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

十万大山盆地北缘侏罗纪轮藻的发现及意义     

蒙有言 《南方国土资源》2000,13(3):19-21

在十万大山盆地北缘的中小型盆地红层中首次发现侏罗纪的轮藻类植物化石.共计2个属,7个种,2个未定种.文章根据轮藻组成特征,讨论了这些中小盆地的地质时代,认为属早中侏罗世,为十万大山盆地侏罗纪红层的研究提供了新的线索.  相似文献   

An analysis of the balance of operational water discharge using a combined water-intake system   总被引：2，自引：0，他引：2  

Ye. A. Filimonova 《Moscow University Geology Bulletin》2009,64(4):265-268

Possibilities of increasing the available water resources of small-river basins using combined water-intake systems are considered. The modern system of water intake, whose balance is supplied at the expense of reduced river flow, remains the main water-intake system. During low-water periods, a compensation water-intake system is used for maintaining the minimum permissible stream flow. The sources of compensation water-intakes are analyzed.  相似文献   

黔中小流域水体C、S同位素特征及主要风化过程   总被引：1，自引：0，他引：1  

薛彦山  季宏兵  江用彬 《地球化学》2009,38(3):262-272

选取贵州省红枫湖流域四条支流为研究对象,通过对水体中C、S元素浓度及稳定同位素特征的分析,探讨了典型碳酸盐小流域的主要风化过程对流域C、S循环的贡献。红枫湖流域河水中的C同位素组成在-7．47‰--11．68‰之间,硫酸根浓度为295．5～1315．6μmol／L,除受当地煤矿影响较大的区域外,其余部分水体中离子的δ^34S值在-3‰--7‰之内,反映了这些河段中硫化物矿物的氧化的影响。通过质量守恒的方法,得到硫化物的氧化、蒸发岩溶解以及大气输入对河水硫酸根离子的贡献率分别为63．8％、30．8％和5．4％。来自硫酸对碳酸盐岩、碳酸对碳酸盐岩以及碳酸对硅酸盐岩风化的DIC比例为1：3．58：1．37,三种不同的风化过程对区域二氧化碳的净吸收量为7．97×10^9mol／a。  相似文献