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781.
Taking the development of export-oriented economy (the strength and temporal sequence) as a main line, this paper discusses
and analyses the position and role of Wuhan, which is the biggest metropolis in the central China and the middle section of
the Changjiang (Yangtze) River basin, in the regional economic macro-strategy of China from a new visual sight. On the basis
of the background of a large economic triangle constructed by Hongkong, Wuhan and Shanghai, the paper discusses the relations
between Wuhan and Hongkong, Wuhan and Shanghai. The aim of the paper is to provide some new evidences for the development
of great regional economy of China under the copropelling of the three great economic pivots.
Supported by the National Natural Science Foundation of China. 相似文献
782.
在当前岩土工程施工装备、工艺日趋完善的情况下,正确掌握其发展动向,合理地配置装备和工艺;在承揽各类型岩土工程施工中,应注意发挥已拥有的建筑设计,基础施工、地面建筑、工程质量检测的高技术领域,组成综合服务体系,以获取最大的经济效益。 相似文献
783.
Short dipoles are a key element in new low frequency array antennas as proposed for LOFAR and other astronomical applications. Unfortunately standard texts on short dipole antennas are based on the effective area and do not lead to an astronomically useful sensitivity formulation in a straightforward manner. The concept of maximum effective area is applied to arrays of short dipoles and allows expressing the sensitivity as the ratio of this area over the effective sky brightness temperature as long as the output noise power is dominated by the antenna input radiation. For both quantities we only need to know the array directivity pattern that includes the mutual coupling effects when the actual loading conditions of the array elements are taken into account. Short dipole elements have a constant directivity pattern for frequencies below resonance, but they exhibit strong complex impedance variations that provide only narrow band performance when power matching is applied as required in transmit applications. However, in receive applications voltage or current sensing can be realized, for example with an active balun. Assisted by the steep increase of the sky brightness with wavelength for frequencies below 300 MHz, this can provide sky noise dominated performance over at least a three to one frequency range. Still the low frequency limit is determined by the amplifier noise contribution and the losses in the antenna and in the dielectric ground surrounding the elements. We show that for a sparse array with the elements non-uniformly distributed according to an exponential shell model, a constant sensitivity can be obtained over a frequency range of at least two octaves. In addition, such a configuration has a factor of six greater sensitivity than a rectangular array for a large part of the frequency band. 相似文献
784.
云南施甸县传统农业发达。在封闭的年代,粮食、肉食、油料自给略有余,小有名气。改革开放后,由于观念陈旧落后,资源又相对贫乏,加上人多地少,工业基础差,财源少,成为保山地区的“困难户”,这是一种特殊现象。本文就是研究产生这一现象的背景原因,以及发展经济的策略途径和相应的措施。 相似文献
785.
Hybrid tilapia were reared at densities of 1, 5 or 10 fish per tank for four weeks. Mortality was 0 at 1 and 10 fish per tank,
but was 25% at 5 fish per tank. Specific growth rate was highest at 1 fish per tank, and lowest at 5 fish per tank. The lower
growth rate at the intermediate stocking density was associated with reduced feed efficiency, but there was no reduction in
feed intake or digestibility. The results suggested increased metabolic cost caused by aggressive behaviour at intermediate
stocking density, which can be suppressed by a further increase in density.
This project was financially supported by the State Key Laboratory of Freshwater Ecology and Biotechnology of China and by
Shanghai Fisheries University (Project SFU. 200003). 相似文献
786.
《The Professional geographer》1983,35(4):488-524
Book Reviewed in this article: Main Street: Northeastern Oregon: The Founding and Development of Small Towns . Barbara Ruth Bailey . Food Politics: The Regional Conflict . David N. Balaam and Michael J. Carey , eds. The International Economy and Industrial Development: Trade and Investment in the Third World . R. Ballance , J. Ansari and H. Singer . Neighborhoods in Urban America . Ronald H. Bayor , ed. The English Heartland . By Robert Beckinsale and Monica Beckinsale . Regional Dimensions of Industrial Policy . Michael E. Bell and Paul S. Lande , eds. Tension Areas of the World . D. Gordon Bennett , ed. Latin America: an Introductory Survey . B. W. Blouet and O. M. Blouet , eds. Integration and Division: Geographical Perspectives on the Northern Ireland Problem . Frederick W. Boal and J. Neville H. Douglas , eds. Energy and Land Use . Robert W. Burchell and David Listokin , eds. Slopes and Weathering . Michael Clarke and John Small . Alaska's Rural Development . Peter G. Cornwall and Gerald Mc Beath , eds. The Politics of Park Design: A History of Urban Parks in America . Galen Cranz . World Congress on Land Policy, 1980, Proceedings . Matthew Cullen and Sharon Woolery , eds. Oregon Divided: A Regional Geography . Samuel N. Dicken and Emily F. Dicken . Urban Food Marketing and Third World Rural Development . T. Scarlett Epstein . South Africa: Spatial Frameworks for Development . T. J. D. Fair . Institutions and Geographical Patterns . Robin Flowerdew , ed. Industrialization of U.S. Agriculture, An Interpretive Atlas . Howard F. Gregor . Planning Theory: Prospects for the 1980s . Patsy Healy , Glen Mc Dougall and Michael J. Thomas , eds. Neighborhood Mobilization: Redevelopment and Response . Jeffrey R. Henig . The American Urban System: A Geographical Perspective . R. J. Johnston . Climate, History and the Modern World . Hubert H. Lamb . Climate and History: Studies in Past Climates and Their Impact on Man . T. M. L. Wigley , M. J. Ingram and G. Farmer . China: Railways and Agricultural Development, 1875–1935 . Ernest P. Liang . A Desirable Energy Future—A National Perspective . Robert S. Livingston , T. D. Anderson , T. M. Besmann , M. Olszewski , A. M. Perry , and C. D. West . Topothesia: Essays Presented to T. S. Ó Máille . B. S. Mac Aodha , ed. Transportation for the Poor: Research in Rural Mobility . Hal S. Maggied . Land Uses in American Cities . Harold M. Mayer and Charles R. Haves . Industrial Organisation and Location . Philip Mc Dermott and Michael Taylor . Human Adaptability: an Introduction to Ecological Anthropology . Emilio F. Moran . Regional Analysis and the New International Division of Labor . Frank Moulaert and Patricia W. Salinas , eds. The Nuclear War Atlas. Victoriaville, Quebec, Canada : Urbanization and Environmental Quality . Isao Orishimo . The Garden of Eden: The Botanic Garden and the Re-Creation of Paradise . John Prest . Earthfire, The Eruption of Mount St. Helens . Charles Rosenfeld and Robert Cooke . Contest for the South China Sea . Marwyn S. Samuels . The Future of the Wetlands: Assessing Visual-Cultural Values . Richard C. Smardon , ed. Tucson: the Life and Times of An American City. C. L. Sonnichsen . The Geography of Multinationals . Michael Taylor and Nigel Thrift , eds. Impact of Marine Pollution on Society . Virginia Tippie and Dana Kester . Reviving the Industrial City: the Politics of Urban Renewal in Lyon and Birmingham . Jerry A. Webman . Andean Reflections: Letters from Carl O. Sauer While on a South American Trip under a Grant from the Rockefeller Foundation, 1942 . Robert C. West , ed. Cartographic Drawing with Computers . P. Yoeli . 相似文献
787.
尹年长 《广东海洋大学学报》2006,26(2):6-11
1982年《联合国海洋法公约》确立了专属经济区制度,规定了沿海国对200海里专属经济区享有公约规定的主权权利和管辖权。专属经济区是一个既不同于公海又有别于领海的特殊海域,沿海国家对专属经济区的主权权利是国家经济主权的组成部分,公约的规定是尊重国家主权的。我们应充分利用公约的规定,积极维护我国专属经济区的国家主权权利。 相似文献
788.
农业作为响应气候变化最敏感的领域之一,未来作物产量可能受到深刻影响。量化气候变化冲击作物产量导致的最终经济影响,需要综合“气候变化—作物产量—经济影响”开展链式研究。文中采用系统回顾和Meta回归分析方法整合了55篇文献的667项研究结果,推导出我国七大地区主要作物(水稻、玉米、小麦)产量与地区内未来温度和降水变化的定量关系,并将其作为农业部门的损失量代入改进的多区域投入产出模型,量化七大地区内与地区间遭受的经济波及影响(ERE)。结果显示:(1)气候变化对我国作物产量的影响主要体现在温度升高上,每升温1℃减产2.6%~12.7%,东北和西北地区作物受升温影响最显著;(2) 气候变化导致的作物减产将对经济产生更严重的波及影响,GDP因作物减产每下降1%将额外产生17.8%的波及影响;(3) 21世纪末,若不考虑CO2肥效作用,作物减产导致的ERE将占GDP的-0.1%~13.6%(负值表示收益),最悲观情况下ERE与当前我国农业总产值相当(2012年为基准年);(4)不同地区受ERE影响程度的差异较大,因各区之间产业结构、贸易联系及经济发展程度存在差异,西南地区遭受本区及来自其他地区的ERE比华东地区高2.8~8.5倍。 相似文献
789.
林业作为实施“基于自然的解决方案(NbS)”的重要领域和路径选择,在落实NbS行动中越来越受到各国政府和专家学者的广泛支持。文中在回顾国内外NbS相关资料的基础上,总结分析了林业领域NbS的内涵和路径、国际和国内相关政策及已采取的措施,重点分析了林业NbS路径的减排潜力、成本与效益。从全球范围看,造林和再造林路径具有较高的技术减排潜力,而减少毁林和森林经营管理是相对更具有成本效益的增汇减排路径。中国对林业NbS的实践及科学研究等尚显不足,但已有的重大林业生态工程已经产生了显著的减排效益和经济效益。未来需要在林业NbS相关标准与计量体系建设、减排技术与经济潜力研究、激励与保障机制等政策研究,以及增强公众意识等方面进一步深化和发展。 相似文献
790.
地震灾害是人类面临的重大考验,阿尔法导航系统在地震预报领域有着重要的科研及应用价值。以2010年4月13日23时49分(世界时)玉树MS 7.1地震为例,基于2010年4月6日—13日阿尔法导航系统超低频(VLF)电波场强和相位数据,使用滑动四分位法,分析该系统9条链路上的信号异常,结合地磁“低点位移”现象,综合分析此次地震前的异常变化。研究结果表明:在地磁活动平静时段,玉树MS 7.1震前3天及震前23 h,电波场强数据出现明显畸变,表现为持续1—6 h超阈值的异常扰动,最大扰动幅度超过阈值13.6 μV/m,相位数据未出现明显异常。结合震前3天阿尔法导航系统主台—通海台、西副台—雅安台异常链路以及震前47天地磁“低点位移”分界线的重叠位置,可进一步精确临震预报时刻,并提高发震位置的预测精度。 相似文献