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991.
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994.
论长江三角洲都市经济圈的形成及其核心城市上海的功能定位 总被引：9，自引：2，他引：9
加快形成长江三角洲都市经济圈及充分发挥上海的核心功能，不仅对于加快长江三角液地区经济的持续，快速，健康发展具有重要意义，而且也将对贯彻国家长江发展战略和西部大开发战略起到积极推动作用，通过分析形成长江三角洲都市经济，圈的理论基础和主要发展思路，从区域经济协调发展的角度，提出上海作为该地区的首位城市，应当在产业结构升级，区域 要素市场培育，综合交通运输网构建及区域经济一体化服务建设等四方面发挥核心城市的;功能。 相似文献
995.
Garnet-sillimanite gneisses, locally known as khondalites, occur abundantly in the Chilka Lake granulite terrane belonging
to the Eastern Ghats Proterozoic belt of India. Though their chemistry has been modified by partial melting, it is evident
that the majority of these rocks are metapelitic, with some tending to be metapsammitic. Five petrographically distinct groups
are present within the khondalites of which the most abundant group is characteristically low in Mg:Fe ratios — the main chemical
discriminant separating the five groups. The variations in Mg:Fe ratios of the garnets, biotites, cordierites, orthopyroxenes
and spinels from the metapelites are compatible with those in the bulk rocks.
A suite of granitoids containing garnet, K-feldspar, plagioclase and quartz, commonly referred to as leptynites in Indian
granulite terranes, are interlayered with khondalites on the scale of exposures; in a few spots, the intercalated layers are
thin. The peraluminous character of the leptynites and presence of sillimanite trails within garnets in some of them suggest
derivation of leptynites by partial melting of khondalites. Here we examine this connection in the light of results derived
from dehydration melting experiments of micas in pelitic and psammitic rocks.
The plots of leptynites of different chemical compositions in a (MgO + FeO)-Na2O-K2O projection match the composition of liquids derived by biotite and muscovite dehydration melting, when corrected for co-products
of melting reactions constrained by mass balance and modal considerations. The melt components of the leptynites describe
four clusters in the M-N-K diagram. One of them matches melts produced dominantly by muscovite dehydration melting, while
three clusters correspond to melting of biotite. The relative disposition of the clusters suggests two trends, which can be
correlated with different paths that pelitic and psammitic protoliths are expected to generate during dehydration melting.
Thus the leptynites evidently represent granitoids which were produced by dehydration melting in metapelites of different
compositions.
The contents of Ti, Y, Nb, Zr and Th in several leptynites indicate departures from equilibrium melt compositions, and entrainment
of restites is considered to be the main causative factor. Disequilibrium in terms of major elements is illustrated by leucosomes
within migmatites developed in a group of metapelites. But the discrete leptynites that have been compared with experimental
melts approach equilibrium melt compositions closely. 相似文献
996.
The usefulness of coal petrography for assessing and evaluating the properties of coal is well established. Such study is particularly helpful for evaluating Indian coals which are conspicuously heterogenous in nature. In a comparative study on the various schemes of classification and codification of coal using petrographic parameters, the importance of an international petrographic classification has been stressed. In the light of such a scheme—originally suggested for categorising Indian coals using vitrinite and exinite contents and reflectance of vitrinite as parameters—an attempt has been made to define the various important coal deposits of the subcontinent. They appear to be remarkably amenable to national planning from the standpoint of coal utilization. 相似文献
997.
998.
Simultaneous observations of stratospheric organic and inorganic chlorine were made in September 1993 out of Fort Sumner, New Mexico, using JPL balloon-borne MkIV interferometer. Between 15 and 20 km, a significant fraction (20-60%) of the inorganic chlorine could not be accounted for by the sum of measured HCl, ClONO2, and HOCl. Laboratory measurements of the reaction of ClO radicals on sulfuric acid solutions have indicated that, along with HCl, small amounts of perchloric acid, HClO4, were formed. Very little is known about the fate of HClO4 in the stratosphere and we use a photochemical box model to determine the impact of this new species on the partitioning of inorganic chlorine in the stratosphere. Assuming that HClO4 is photochemically stable, it is shown that in the enhanced aerosol loading conditions resulting from Mt. Pinatubo's eruption, HClO4 could represent a significant reservoir of chlorine in the lower stratosphere, sequestering up to 0.2 ppbv (or 50%) of the total inorganic chlorine at 16 km. The occurrence of this new species could bring to closure the inorganic chlorine budget deficiency made apparent by recent ER-2 aircraft in situ measurements of HCl. 相似文献
999.
Developing an effective approach to rapidly assess the effects of restoration projects on soil erosion intensity and their extensive spatial and temporal dynamics is important for regional ecosystem management and the development of soil conservation strategies in the future. This study applied a model that was developed at the pixel scale using water soil erosion indicators (land use, vegetation coverage and slope) to assess the soil erosion intensity in the Loess Plateau, China. Landsat TM/ETM+ images in 2000, 2005 and 2010 were used to produce land use maps based on the object-oriented classification method. The MODIS product MOD13Q1 was adopted to derive the vegetation coverage maps. The slope gradient maps were calculated based on data from the digital elevation model. The area of water soil-eroded land was classified into six grades by integrating slope gradients, land use and vegetation coverage. Results show that the Grain-To-Green Project in the Loess Plateau worked based on the land use changes from 2000 to 2010 and enhanced vegetation restoration and ecological conservation. These projects effectively prevented soil erosion. During this period, lands with moderate, severe, more severe and extremely severe soil erosion intensities significantly decreased and changed into less severe levels, respectively. Lands with slight and light soil erosion intensities increased. However, the total soil-eroded area in the Loess Plateau was reduced. The contributions of the seven provinces to the total soil-eroded area in the Loess Plateau and the composition of the soil erosion intensity level in each province are different. Lands with severe, more severe and extremely severe soil erosion intensities are mainly distributed in Qinghai, Ningxia, Gansu and Inner Mongolia. These areas, although relatively small, must be prioritised and preferentially treated. 相似文献
1000.
欢乐谷地区由新元古代泥砂质岩层夹铁镁质岩层组成。受达马拉期陆块碰撞事件的影响,发生区域中深地壳层次的强烈韧性变形。后碰撞期,在地壳增厚背景下,发生大规模伸展减薄和花岗岩浆作用,形成多种浅色花岗岩体即白岗岩。产铀白岗岩主要为D型及E型白岗岩,为S型壳源花岗岩。欢乐谷地区经历了四期五个阶段的构造演化,分别是:前达马拉期构造变形、达马拉碰撞造山期韧性变形(早阶段的挤压逆冲、晚阶段的走滑剪切韧性变形)、后达马拉期脆性变形和新生代整体抬升引起的脆性变形。广泛发育的白岗岩属于同构造期岩体。通过对变质岩和白岗岩的节理测量统计,基本确定了研究区的碰撞后区域应力场。最优势的主压应力方向介于N26°~35°方位间,其次为介于N110°~129°方位间和N345°~360°方位间的主压应力。目前保留在各类岩石中的密集节理构造,是碰撞造山后构造折返或岩浆上涌到达上地壳层次后才发生的,与铀矿富集关系密切。本研究初步探讨了达马拉期构造作用、韧性剪切、后期脆性断裂(基性岩墙侵位通道)与铀成矿作用的成因联系和制约作用。 相似文献