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881.
河南祁雨沟爆破角砾岩型金矿床包裹体研究 总被引:10,自引:1,他引:10
本文通过包裹体研究了祁雨沟爆破角砾岩型金矿床成矿流体来源、性质和成矿物理化学条件,为该类型金矿找矿与评价提供依据。 相似文献
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In this paper, on the basis of intensity data from 85 earthquakes occurred in China, the method of resolving overdetermined equations by using the damped least squares method is applied to inversing for the mean value of 1 s. S wave quality factor, the spreading factor and the S-wave acceleration at the foci of earthquakes in 7 regions of China. The relation between S-wave acceleration at the foci of earthquakes and magnitude is discussed. As an example, 2-DQ S distribution in Taiwan Province is obtained by inversion. It is found that there exists some corresponding relation between this distribution and Bouguer gravitational anomaly and seismicity. Preliminary analysis and discussion on results of the inversion, and estimation of error inQ S are made. 相似文献
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Abstract Based on the Rb-Sr isotopic study of the granitoids in the Hengduan Mountains, the classification and geologic significance of whole- rock Rb- Sr isochrons as well as the factors influencing homogenization of the isotopic systems are discussed. Usually, there is no good linear correlation of isochrons for diorites and alkali-rich intrusive rocks (including alkaline rock and alkalic granite). But by means of the external isochron of monominerals from the rocks, isochrons with good linear correlation as well as ages and Sr initial ratios with a high confidence can be obtained. In order to obtain a satisfactory isochron, the discriminant parameters should be calculated from the Rb / Sr ratios and estimated ages of samples. Only those that meet the requirements can be used as the Rb-Sr isochrons. The quality of an isochron should be judged from three factors, i.e. correlation coefficient, MSWD and homogenization degree. 相似文献
887.
TCM-90现场科学试验台风FLO“β陀螺”“通风流”非对称动力结构特征 总被引:9,自引:3,他引:6
采用TCM-90台风现场科学试验期间加密观测资料,揭示出目标台风Flo非对称动力、热力结构及其转向运动的特征,尤其通过分离处理的偏差场,突出了TCM-90现场试验有关飞机下投(dropsonde)加密探测资料对台风Flo内部非对称结构物理图象的描述,提出了实际台风动力结构存在类似Gray认为的非对称偶极子型,即中低层“β陀螺”偶极子型(β-topdipole),及其“通风流”(Ventilationflow)特征,高层辐合-辐散结构的变形偶极子系统概念模型,并认为这类三维非对称结构对台风运动(转向现象)有一定“引导”作用。文中还强调了“β陀螺”偶极子非对称结构的垂直差异,并揭示了目标台风暖心结构及其热力非对称结构特征。 相似文献
888.
超临界水的特性及其对地球深部物质研究的意义 总被引:5,自引:1,他引:5
水在超临界状态下有着与标准状态明显不同的行为,超临界水具有许多的特殊性质,如强烈的氧化作用,很强的溶解性能,以及通过温度和压力变化控制其密度在类似蒸汽到类似液体的密度之间等。水在约400℃的超临界温度下,几乎有的氢键都裂解了,超临界水的这一性质很可能是超临界水具有许多特殊性质的主要原因,超临状态地幔水的存在,不仅对球物理场的性质有重要影响,崦且对于地质构造演化、地球化学动力学、成矿作用,以及深部地 相似文献
889.
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
890.
The perforated breakwater is an environmentally friendly coastal structure,and dissolved oxygen concentration levels are an important index to denote water quality.In this paper,oxygen transport experiments with regular waves through a vertical perforated breakwater were conducted.The oxygen scavenger method was used to reduce the dissolved oxygen concentration of inner water body with the chemicals Na_2SO_3 and Co Cl_2.The dissolved oxygen concentration and wave parameters of 36 experimental scenarios were measured with different perforated arrangements and wave conditions.It was found that the oxygen transfer coefficient through wave surface,K_1a_1,is much lower than the oxygen transport coefficient through the perforated breakwater,K_2a_2.If the effect of K_1a_1 is not considered,the dissolved oxygen concentration computation for inner water body will not be greatly affected.Considering the effect of a permeable area ratio α,relative location parameter of perforations δ and wave period T,the aforementioned data of 30 experimental scenarios,the dimensional analysis and the least squares method were used to derive an equation of K_2a_2(K_2a_2=0.0042α~(0.5)δ~(0.2)T~(-1)).It was validated with 6 other experimental scenarios data,which indicates an approximate agreement.Therefore,this equation can be used to compute the DO concentration caused by the water transport through perforated breakwater. 相似文献