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211.
构建城市地理信息共享平台标准体系的思考   总被引:4,自引:0,他引:4  
通过分析城市地理信息共享平台建设的动因,指出标准体系的重要性,剖析其目的和意义.在此基础上,深入思考了标准体系的构建原则和构建方法,从数据、技术和管理三个维度探讨了标准体系的内容结构,并给出数字深圳空间基础信息平台标准体系工程实例分析.  相似文献   
212.
《The Journal of geography》2012,111(4):146-157
Abstract

Active learning strategies include a variety of methods, such as inquiry and discovery, in which students are actively engaged in the learning process. This article describes several strategies that can be used in secondary-or college-level world geography courses. The goal of these activities is to foster development of a spatial perspective in students through frequent analysis and interpretation of spatial data. Detailed examples of one particular technique, the “atlas warmup”, are included. Active approaches supplement expository teaching of standards-based geography concepts and current geographic issues. Assessment of the impact of these methods reveals the need for ongoing guided practice in the use of these skills.  相似文献   
213.
《The Journal of geography》2012,111(5):527-529
Abstract

This article deals with the issue of providing geographic training to prospective teachers from the perspective of a secondary school teacher who also teaches a social studies methods course. Research in educational journals provided a background for describing the lack of geographic training among social studies teachers. While the National Geographic Society's alliance network is addressing this issue among practicing teachers, there is still a need to include some geography training for preservice teachers. Suggestions are offered for including geography within the context of the social studies methods course. A plea is also made for geography professors to include the new National Geography Standards in their courses, especially in introductory courses.  相似文献   
214.
(极)年轻火山岩激光熔蚀40Ar/39Ar定年   总被引:1,自引:2,他引:1  
对中国大量年轻或/和极年轻火山岩的定年实践研究表明,(极)年轻火山岩的激光熔蚀40Ar/39 Ar定年具有不同于第四纪以前喷发火山岩定年的显著特点.激光熔蚀40Ar/39Ar定年技术因为本底低、样品用量小以及与现代惰性气体同位素质谱设备在灵敏度、高精度方面的相一致,在年轻火山岩的定年中得到深入运用.借助激光在年轻或/和极年轻火山岩的40 Ar/39 Ar定年中,实践证明,样品形成时限越年轻(特别是相当于第四纪时期的样品),Nier值与样品中初始氩比值的偏离会引起K-Ar和40Ar/39 Ar表观年龄的偏差越大.对于小于0.2Ma的样品,Nier值与样品中初始氩比值的偏离对K-Ar和40Ar/39Ar表观年龄的偏差影响呈指数增长;当样品年龄相对较老(老于第四纪)时,Nier值和初始氩比值的偏离对K-Ar和40Ar/39 Ar表观年龄的影响较小.以40Ar/ArAr定年为出发点,定量给出界定年轻与极年轻火山岩的年龄:2~0.2Ma的火山岩界定为年轻火山岩,0.2Ma以来的火山岩称为极年轻火山岩.实验结果还证实,测定(极)年轻火山岩基质年龄时要尽量剔除非同源分馏的斑晶,以便去除斑晶可能带来的过剩氩影响;年轻火山岩样品的测年,应根据岩石结构和粒度特征选取合适的粒度,通常情况下,推荐0.2mm颗粒直径(60~80目)为理想粒径;年轻火山岩样品在快中子辐照后冷却放置时间不宜过长,否则造成37 Ar测不准,影响数据结果,带来较大偏差;激光40Ar/39Ar精细定年对标准样品的均一性有很高的要求,通过标定常用的国内外监测标样发现,标样SB-778-Bi,Bem4M,BT-1均一性很好,适合用作激光熔蚀40Ar/39Ar定年监测;测试数据的处理中,火山岩喷发后冷却结晶中同时形成的斑晶和基质的等时线处理能够帮助获得客观真实和精细的年龄结果.在此基础上,北京大学惰性气体同位素实验室建成了专用于(极)年轻火山岩精细定年的激光熔蚀40Ar/39Ar定年实验流程.  相似文献   
215.
Clocks that receive and decode time signals from the GOES satellites are commonly used to provide accurate time reference for the recording of a wide variety of data types in academic research. These satellite clocks must be used with adequate knowledge of their operation. When corrections for satellite position are not made, comparison data presented in this paper show that errors of up to several milliseconds will result. However, with care and the application of proper corrections it is shown that accuracies of 100 to 200 microseconds are achievable.  相似文献   
216.
胶州湾底质痕量元素污染研究   总被引:13,自引:0,他引:13  
为了查清胶州湾表层沉积物的痕量污染元素对环境的影响,于2002-2004年对胶州湾全区进行了详细的污染调查,并对所获取的312 个表层沉积物样品中的痕量元素按海洋沉积物质量标准进行了评价研究,其中铜有 33 个站位超第一类标准,有 2 个站位超第二类标准,1 个站位超第三类标准.铜在研究区是最严重的污染元素,其污染面广,程度深.铬的污染面仅次于铜,有 29 个站位的样点超标.汞有 22 个站位超标,其中有 5 个站位超第二类标准,1个站位超第三类标准,虽然它的污染面较铜和铬小,但污染程度较严重.锌有 7 个站位超标,其中1个站位超第二类标准.镉的污染程度较低,只有 3 个站位超标.铅的沉积环境较好,只有 2 个站位的含量值超第一类标准.研究区污染最轻的痕量元素是砷.结果表明,这些痕量元素主要为工业和生活污水经排污沟和排污河而进入胶州湾.按其污染范围大小排序是:铜>铬>汞>锌>镉>铅>砷;按其污染程度排序是汞>铜>铬>锌>镉>铅.  相似文献   
217.
方雯  钱云霞 《台湾海峡》2009,28(4):488-491
利用SYBR荧光定量PCR技术,制备用于花鲈(Lateolabrax japonicus)PPARα基因实时荧光定量PCR检测的质粒标准品.通过PCR扩增出目的片断344-bp,纯化后连接至pMDI8-T载体,转化宿主菌E.coli DH5α.通过PCR鉴定、双酶切鉴定和测序分析后抽提重组质粒,测定其拷贝浓度,10倍梯度稀释成标准品模板10^8~10^4 copy/mm^3,进行荧光定量PCR分析.结果显示,循环阈值(Ct)与起始模板量的对数值之间有着良好的线性关系.  相似文献   
218.
BOOK REVIEWS     
Book Reviewed in this article: The City in Cultural Context . John Agnew, John Mercer, David Sopher, eds. Soils and Geomorphology Peter W. Birkeland. Urbanization and Settlement Systems, International Perspectives . L. S. Bourne, R. Sinclair, and K. Dziewoński. eds. An Introduction to Urban Historical Geography . Harold Carter. Overshoot, The Ecological Basis of Revolutionary Change . William J. Catton, Jr. Rivers of the World . Eberhard Czaya. Jewish Communities in Frontier Societies: Argentina, Australia and South Africa . Daniel J. Elazar with Peter Medding. Color in Public Spaces: Toward a Communication-Based Theory of the Urban Built Environment. Kenneth E. Foote. Spatial Statistics and Models. Gary L. Gaile and Cort J. Willmott, eds. Mega-Geomorphology. Rita Gardner and Helen Scoging, eds. Technological Change and Regional Development. Gillespie, ed. The Arid Lands: Their Use and Abuse. R. L. Heathcote. The Location of Industry in Britain. A. G. Hoare. Groundwater as a Geomorphic Agent . R. G. LaFleur, ed. Rural Public Services: International Comparisons. Richard E. Lonsdale and Gyorgy Enyedi, eds. Saving Water in a Desert City. William E. Martin, Helen M. Ingram, Nancy K. Laney, and Adrian H. Griffin. Water Resources: Distribution, Use and Management. John R. Mather. Transnationals and the Third World: The Struggle for Culture. Armand Mattelart. South Hadley, MA: USGS Digital Cartographic Data Standards. R. B. McEwen, R. E. Witmer, and B. S. Ramey, eds. The Ecosystem Concept in Anthropology. Emilio F. Moran, ed. Boulder, CO: Women, Men, and the International Division of Labor. June Nash and Maria Patricia Fernandez-Kelly, eds. Nuclear Power: Assessing and Managing Hazardous Technology. Martin J. Pasqualetti and K. David Pijawka, eds. Mary Somerville and the Cultivation of Science 1815-1840. Elizabeth Chalmers Patterson. An Introduction to Coastal Geomorphology. John Pethick. Late Quaternary Environments of the United States , Vol. 1, The Late Pleistocene. Stephen C. Porter, ed. Planning and Ecology. R. D. Roberts and T. M. Roberts, eds. Regionalism and the Pacific Northwest. William G. Robbins, Robert J. Frank, and Richard E. Ross, eds. Environment and Health. Anthony J. Rowland and Paul Cooper. Sunbelt/Snowbelt: Urban Development and Regional Restructuring. Larry Sawers and William K. Tabb, eds. The Bad Earth. Environmental Degradation in China. Vaclav Smil. Armonk, NY: Voyage into Substance: Art, Science, Nature, and the Illustrated Travel Account, 1760–1840. Barbara Maria Stafford. The Institute of British Geographers: The First Fifty Years. Robert W. Steel. Visions of the Past. Christopher Taylor and Richard Muir. Glacial Lake Agassiz. J. T. Teller and Lee Clayton, eds. The Tule Breakers: The Story of the California Dredge. John Thompson and Edward A. Dutra. The Balkan City 1400–1900. Nikolai Todorov. Explanation, Prediction and Planning: the Lowry model. Michael J. Webber. Mercedes Reales: Hispanic Land Grants of the Upper Rio Grande Region. Victor Westphall. The World Atlas of Revolutions. Andrew J. M. Wheatcroft. The West European City, A Social Geography. Paul White. Urban Elites and Mass Transportation. J. Allen Whitt. Princeton, NJ: Urban Life In Contemporary China. Martin King Whyte and William L. Parish. The Demand for Energy in the Soviet Union. David Wilson. London and Canberra: Rethinking Geographical Inquiry. J. David Wood, ed.  相似文献   
219.
New analyses have been performed in order to enhance the data-set on the independent ages of four glasses that have been proposed as reference materials for fission-track dating. The results are as follows. Moldavite - repeated 40Ar/39Ar age determinations on samples from deposits from Bohemia and Moravia yielded an average of 14.34 ± 0.08 Ma. This datum agrees with other recent determinations and is significantly younger than the 40Ar/39Ar age of 15.21 ± 0.15 Ma determined in the early 1980s. Macusanite (Peru) -four K-Ar ages ranging from 5.44 ± 0.06 to 5.72 ± 0.12 Ma have been published previously. New 40Ar/39Ar ages gave an average of 5.12 ± 0.04 Ma. Plateau fission-track ages determined using the IRMM-540 certified glass and U and Th thin films for neutron fluence measurements agree better with these new 40Ar/39Ar ages than the previously published ages. Roccastrada glass (Italy) - a new 40Ar/39Ar age, 2.45 ± 0.04 Ma, is consistent with previous determinations. The Quiron obsidian (Argentina) is a recently discovered glass that has been proposed as an additional reference material for its high spontaneous track density (around 100 000 cm-2). Defects that might produce "spurious" tracks are virtually absent. An independent 40Ar/39Ar age of 8.77 ± 0.09 Ma was determined and is recommended for this glass. We believe that these materials, which will be distributed upon request to fission-track groups, will be very useful for testing system calibrations and experimental procedures.  相似文献   
220.
新疆地质调查院作为中国地质调查局确定的建立质量管理体系的首批试点单位,2000-2001年探索性地将ISO9001:2000版国际标准应用于地质调查行业中,在行业与ISO9000旋国际标准的联系,1994版与2000版标准版本的对比,转换以及与地质调查行业的结合,质量管理体系建立和实施要点总结等方面均取得了进展。  相似文献   
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