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71.
It is shown that the planetary nebulae can be divided into three types according to the values of the mass of shell and a central star. The criteria are given using which one can determine the mass type of the nebula. The distance scale of each mass-type planetary nebulae is given. The distribution of planetary nebulae in the Galaxy, their formation rate, scale-height and other physical and kinematic characteristics are investigated. A catalogue of planetary nebulae emitting in the radio range is given.  相似文献   
72.
The lithospheric strike‐slip Altyn Tagh Fault has accommodated hundreds of kilometres of displacement between the Qaidam and Tarim blocks since its Eocene reactivation. However, the way the deformation is accommodated in the Qilian Shan and further east remains uncertain. Based on 360 km of north‐eastward migration of the relatively rigid Qaidam block along the Altyn Tagh Fault and 3D isovolumetric balancing of the crustal deformation within the Altyn Tagh Fault–Qilian Shan system, we demonstrate that 250 ± 28 km (43.8–49.4%) of N20E directed crustal shortening and an additional ~250–370 km of eastward motion of the Qilian Shan crust must be accounted for by strike‐slip faulting in the Qilian Shan and crustal thickening in the Qinling area, as well as by extension in the adjoining North China block graben systems.  相似文献   
73.
梁玉  邹滨  冯徽徽  刘宁 《遥感学报》2022,26(8):1602-1613
MODIS 3 km DT (Dark Target)卫星气溶胶光学厚度AOD (Aerosol Optical Depth)数据产品已广泛应用于大气污染监测,但受反演方法限制,该数据产品像元缺失严重、时空覆盖度低、精度偏低。相比,MODIS 10 km DT_DB_Combined AOD数据产品因融合DT和DB (Deep Blue)两种反演算法,一定程度上可弥补MODIS 3 km DT AOD数据产品在时空覆盖度与精度方面的缺陷,但分辨率偏低。此外,受气溶胶组分来源的季节变化与地表反射率估算的季节性误差影响,MODIS AOD数据产品精度同时也存在季节性特征。本文由此以京津冀为试验区,顾及AOD季节变化特性,开展MODIS 10 km DT_DB_Combined AOD数据产品偏差纠正下的地统计反演模拟BGIM(Bias-corrected Geostatistical Inverse Model)降尺度算法研究。试验同时引入AERONET地基观测数据和MODIS3 km DT AOD数据产品作为降尺度结果的绝对与相对验证标准。结果表明:季节偏差系数纠正下生成的MODIS3 ...  相似文献   
74.
A broad sample of computed realistic equations of state of superdense matter with a quark phase transition is used to construct a series of models of neutron stars with a strange quark core. The integral characteristics of the stellar configurations are obtained: gravitational mass, rest mass, radius, relativistic moment of inertia, and red shift from the star's surface, as well as the mass and radius of the quark core within the allowable range of values for the central pressure. The parameters of some of the characteristic configurations of the calculated series are also given and these are studied in detail. It is found that a new additional region of stability for neutron stars with strange quark cores may exist for some models of the equation of state.  相似文献   
75.
Strata behaviors are mainly affected by regional geodynamic background. The influence of rock mass stress and energy distribution on strata behaviors in the Tongxin mine is studied in terms of regional tectonic movement, seismic activity and tectonic stress field. The results show that the extrusion lifting movement of Kouquan fault adjacent to the Tongxin mine results in the stress concentration in the rock of the Carboniferous coal bed and accumulation of a large amount of elastic energy and forms structural background of Tongxin mine. Due to various seismic activities in the mine area, the strain energy is known to reach much higher levels, up to 0.5×108 J1/2. Since the stratigraphic structure is sensitive to the mining operation, the strain energy could cause strong strata behaviors. A special geological structure model of the Tongxin mine is established based on the geodynamic division method. The distribution of regional structure stress field is determined by the rock mass stress analysis system. Based on this model, Tongxin mine is divided into five areas with high stress, eight areas with low stress and eight areas with gradient stress. The strong strata behaviors mostly occur in high stress areas. These results could provide guidance to predict the strength of regional or mine pressure and control strata behavior in different areas.  相似文献   
76.
77.
Izvestiya, Atmospheric and Oceanic Physics - Bioparticles constitute a significant fraction of atmospheric aerosol. Their size range varies from nanometers (macromolecules) to hundreds of...  相似文献   
78.
鄂尔多斯盆地三叠系延长组长7暗色泥页岩是重要的烃源岩。最近的勘探表明,长7具有良好的页岩气开发前景。重点利用鄂尔多斯盆地279口测井资料、18口取心井的347块岩样实验室多种分析测试资料,开展了鄂尔多斯盆地中生界延长组长7页岩气的岩性、岩相、孔隙类型、有机碳含量、热演化程度、含气性、气体储存方式及其在测井曲线的反响研究;在页岩气形成条件的研究基础上,建立了岩性、含气性、有机质含量与自然伽马、声波时差、电阻率之间的关系,有效地识别含气泥页岩;选择容积法对延长组页岩气资源量进行计算,为未来页岩气的勘探和开发奠定基础。  相似文献   
79.
本文较系统地阐述了利山金矿床的各项地质特征,并重点就控矿构造问题进行了总结讨论,认为NWW向断裂带严格控制了所有金矿体的产出。NNE、NNW向断裂与NWW向断裂带的交汇部位控制了富矿段的产出。在此基础上初步探讨了矿床成因及找矿方向,这对该地区的找矿评价和开发均具有实际意义  相似文献   
80.
With the Taihu Basin as a study area, using the spatially distributed and mechanism-based SWAT model, preliminary simulations of nutrient transport in the Taihu Basin during the period of 1995:_2002 has been carried out. The topography, soil, meteorology and land use with industrial point pollution discharge, the loss of agricultural fertilizers, urban sewerage, and livestock drainages were all considered in the boundary conditions of the simulations. The model was calibrated and validated against water quality monitoring data from 2001 to 2002. The results show that the annual total productions of nitrogen (TN) and phosphorus (TP) into Lake Taihu are 40000t and 2000t respectively. Nutrient from the Huxi Region is a major resource for Lake Taihu. The non-point source (surface source) pollution is the main form of catchment sources of nutrients into Lake Taihu, occupied TN 53% and TP 56% respectively. TN and TP nutrients from industrial point pollution discharge are 30% and 16%, and sewerage in both forms of point source and non-point source are TN 31% and TP 47%. Both the loss of agricultural fertilizers and livestock drainages from the catchment should be paid more attention as an important nutrient source. The results also show that SWAT is an effective model for the simulation of temporally and spatially nutrient changes and for the assessment of the trends in a catchment scale.  相似文献   
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