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991.
魏宽义 《地球科学与环境学报》1989,(3)
地质模型的建立,地质思维的正确运用已成为引导地质学前进的两个关键环节。本文以构造地质学领域中近年来的研究成果为基础,探讨了与空间和时间有关的地质思维问题。指出:一个地质现象的观察,一定要结合高一级尺度和低一级尺度的综合研究,才能得出既有形成机制、又有组合规律的全面结论;一个构造形迹,一定要尽力区分出不同的递进变形阶段,以提供以时间为坐标的演化序列。文末,笔者提供了两个研究实例,一个用小构造分析论证区域构造演化,一个据叠加变形原理,把研究对象区分成不同的区段和亚域。 相似文献
992.
KANG Dujuan & WANG Huijun . NZC/LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China . Environmental Fluid Mechanics Laboratory Stanford University Stanford CA USA 《中国科学D辑(英文版)》2005,48(12):2260-2266
Dust storm is a disastrous weather that can cause serious environmental consequences and hazards. It causes excessive soil mass and nutrient loss in source areas, and air pollution in deposition area, which result in bad influence on agriculture, industry, traffic, and peoples’ daily life[1-4]. Dust storm can also affect the thermal balance of planetary radiation and then lead to meso- to macroscale climatic modification[5-7]. North- west China and North China are two high-frequency centers … 相似文献
993.
A new algebraic turbulent length scale model is developed, based on previous one-equation turbulence modelling experience in atmospheric flow and dispersion calculations. The model is applied to the neutral Ekman layer, as well as to fully-developed pipe and channel flows. For the pipe and channel flows examined the present model results can be considered as nearly equivalent to the results obtained using the standard k– model. For the neutral Ekman layer, the model predicts satisfactorily the near-neutral Cabauw friction velocities and a dependence of the drag coefficient versus Rossby number very close to that derived from published (G. N. Coleman) direct numerical simulations. The model underestimates the Cabauw cross-isobaric angles, but to a less degree than the cross-isobar angle versus Rossby dependence derived from the Coleman simulation. Finally, for the Cabauw data, with a geostrophic wind magnitude of 10 ms–1, the model predicts an eddy diffusivity distribution in good agreement with semi-empirical distributions used in current operational practice. 相似文献
994.
Environmental records of lacustrine sediments in different time scales: Sediment grain size as an example 总被引:2,自引:0,他引:2
CHEN Jing’an WAN Guojiang David Dian Zhang ZHANG Feng & HUANG Ronggui . State Key Laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang China . Department of Geography Geology University of Hong Kong Pokfulam Road Hong Kong China 《中国科学D辑(英文版)》2004,47(10):954-960
Understanding the past is the key to know thepresent and to predict the future. As a core project ofthe International Geosphere Biosphere Program, PastGlobal Changes (PAGES) aims to reconstruct theevolution history of global climate, global environ-ment and global ecosystem with resort to all kinds ofnatural records, so as to reveal the change rules(change processes, change amplitude and change rate)of the global environment and thus provide scientificbasis for predicting climate changes p… 相似文献
995.
An investigation of analysis of variance as a tool for exploring regional differences in strong ground motions 总被引:2,自引:1,他引:1
The statistical technique known as analysis of variance is applied to a large set of European strong-motion data to investigate whether strong ground motions show a regional dependence. This question is important when selecting strong-motion records for the derivation of ground motion prediction equations and also when choosing strong-motion records from one geographical region for design purposes in another. Five regions with much strong-motion data (the Caucasus region, central Italy, Friuli, Greece and south Iceland) are investigated here. For the magnitude and distance range where there are overlapping data from the five areas (2.50 Ms 5.50, 0 d 35 km) and consequently analysis of variance can be performed, there is little evidence for a regional dependence of ground motions. There is a lack of data from moderate and large magnitude earthquakes (Ms > 5.5) so analysis of variance cannot be performed there. Since there is uncertainty regarding scaling ground motions from small to large magnitudes whether ground motions from large earthquakes are significantly different in different parts of Europe is not known. Analysis of variance has the ability to complement other techniques for the assessment of regional dependence of ground motions. 相似文献
996.
997.
998.
简要介绍了目前国际上比较流行的线阵航空数字传感器ADS80的一些基本情况,分析了该传感器的技术优势与应用意义,并对在大比例尺地形图测绘中的应用、技术开发问题进行了初步的讨论;阐述了利用ADS80数据进行1∶500基础测绘生产的工艺流程及成图过程。研究结果表明ADS80数字航空摄影测量系统不但能有效提高作业效率,同时也能显著提高测图精度。 相似文献
999.
KARA DEMPSEY 《Geographical review》2012,102(1):93-110
Monumental constructions are created for a purpose, often as a symbolic representation of a particular vision of a people or a place. Spain's Cidade da Cultura, a museum conceptualized by Galicia's former president with the hubristic goal of creating a world icon, is one such example. Like many iconic constructions, the Cidade da Cultura project was highly contentious and sparked a regionwide political debate, vastly overran its projected cost, and years later remains controversial and incomplete. An actor‐network theory analysis of why the project failed reveals the different roles played by individual components in the vast network of actors, including the monument itself, which came to exercise influence over the outcome of the project. Because the former president could not fully control this expanding network of actors, events soon spun out of control in what became popularly known as “Galicia's Hurricane.” 相似文献
1000.
1993年中国开始从原油输出国变为原油输入国,到2010年,中国的原油进口依赖度高达53%。原油进口来源国的社会经济稳定性、原油运输线路的安全性影响到中国原油进口的安全性。本文根据ITIRI的综合国际贸易投资风险指数和原油运输线路的安全性,设计了中国从其主要原油进口来源国进口原油的风险指数。然后分析了中国各省级行政区对原油进口消费的依赖度,中国六个大区石化工业和八个石油化工基地对进口原油的依赖程度。从而分析了它们对进口原油风险的敏感度。本研究的结论是:第一,中国重要的原油进口来源国比较集中,且集中在社会经济不十分稳定的国家。第二,原油进口风险对沿海地区经济的影响远高于对内陆地区的影响。第三,沪宁杭、琼粤闽和长江中游石化基地是受原油进口风险影响最大的三个基地。根据这些结论,本文提出两方面建议:第一,建议中国原油进口来源与运输方式尽量多元化,以规避风险。第二,中国原油战略储备基地应考虑对原油进口风险敏感度大的地区。 相似文献