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111.
内陆表海聚煤盆地的曾想到处分析 总被引:14,自引:0,他引:14
在华北石炭二叠纪内陆表海聚煤盆地,海侵的突发性和事件性,泥炭沼泽化的广泛性和等时性,是划分其层序内部构成单元的良好界面。研究表明,华北石炭二叠纪内陆表海聚煤盆地的层序结构为“二元结构型”,即“海侵-高位”,缺少低位体系域。海侵体系域由1~2个小层序构成,而高位体系域由小层序构成。体系域恰与小层序组对应,海侵小层序组表现为弱退积-加积型,而高位体系域则表现为弱进积-加积型。小层序为高精度的岩相古地理编图单位,它为解析层序格架和煤聚积规律提供了最可靠的依据。 相似文献
112.
A. Wahab Khair 《Geotechnical and Geological Engineering》1985,3(4):243-259
Summary This paper presents an analysis of causes of bump in a deep coal mine. The analysis consists of in-mine measurement determination, analysis of physical and mechanical properties of mine materials and simulation of mine layout and mining sequence. Major factors contributing to the causes of bump have been reviewed and those that are related to this case have been identified and simulated analytically using a three-dimensional finite element method. 相似文献
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114.
Summary A two dimensional finite element procedure is applied to simulate a coal mining excavation sequence. A procedure with linear solution steps is developed and applied to an idealized mountain cross-section with exceptionally thick coal seams and large dip angle. The results provide information on pillar pressure, floor and roof stability, displacement characteristics and surface subsidence.The results presented here were obtained in the course of research sponsored by the Department of Energy, Mines and Resources, Grant No. 69-2570. 相似文献
115.
Precipitable water measurements made coincident in time and space with direct broadband solar irradiance measurements are used in conjunction with an atmospheric transmission model to derive a parameter whose major dependence is on total aerosol extinction. Irradiance measurements are used to calculate an atmospheric transmission factor (ATF) that is independent of the instrument calibration and the extraterrestrial solar constant. The dependency of the ATF on precipitable water is determined using LOWTRAN5, an atmospheric transmission model with high spectral resolution. Precipitable water measurements are then used to adjust the measured ATF to correspond to an ATF value obtained for a constant precipitable water amount. The remaining variability in the adjusted ATF is due mostly to aerosol extinction. The technique is applied to a 6-year period (1978–1983) for clear-sky mornings at Mauna Loa, Hawaii (MLO). MLO ATF aerosol residuals are compared with independently measured monochromatic aerosol optical depth. Results show that the ATF aerosol residual is nearly equal to the 500 nm aerosol optical depth prior to the eruption of E1 Chichon, at which time a nonlinear time-dependent relationship between the two quantities is evident. ATF aerosol residuals reflect the spectrally integrated aerosol influence on transmission and, therefore, could indicate better than monochromatic optical depth the radiation balance perturbations due to aerosols. The 6-year precipitable water record for MLO, determined from a dual-channel sunphotometer, has a mean value of 0.3 cm. An annual cycle in precipitable water is evident, as is a 4-month 5-standard-deviation drought from December 1982 through March 1983. 相似文献
116.
In this paper, the authors present the results of both macroscopic and microscopic investigations on structure development created by repeated ice lensing in various loamy experiments. Experimental data are compared with observations performed on active forms in High Arctic and Alpine Mountain environments. Those observations are also compared with phenomena observed in fossil periglacial formations of Western Europe. Platy and short prismatic structure formation is bonded to the hydraulic and thermal conditions during ice segregation. When a long series of alternating freezing and thawing affects platy structures, the fabric evolves, also being influenced by slope and drainage conditions: cryoturbations, frostcreep, and gelifluction can appear. They are characterized by specific microfabrics which are better developed with an increasing number of cycles: this is clear in experiments where hydraulic and thermal parameters are better controlled. Vesicles are also a prominent characteristic of the surface horizon in experiments and arctic soils. The genesis of vesicles is discussed on the basis of new observations and is related to the mechanical collapse of frost-created aggregates under the mechanical work of soil air escape during soil saturation by water at thaw. 相似文献
117.
本文用光学方法检查了经野外地质工作者挑选过的天然方解石单晶的光学质量。发现部分晶体的光学均匀性很差,晶体中的光散射颗粒很多,不能满足作为光学介质的要求。 相似文献
118.
Results from long term microerosion meter (MEM) studies indicate that microenvironments are characterized by different erosion rates. A complementary study, carried out on the same sites, examines the microscale morphology in each environment. Optical and scanning electron microscopy were used to identify a range of features thought to reflect different processes. Under subaerial conditions micromorphology is dominated by biological weathering features owing to the presence of microflora. Sites permanently covered by soil or stream water have only dissolution etch features, though stream sites may exhibit microfractures. Sites with periodic exposure exhibit both dissolution and biological etch features. The natural environment is more accurately reflected by allowing some microflora colonization of MEM sites rather than preventing colonization by artificial means. 相似文献
119.
本文通过比较太阳直射表和太阳光度计探测的大气柱气溶胶光学厚度,分析了从太阳直射表探测的全波段太阳直射光强信息确定大气柱气溶胶光学厚度的误差,并应用北京观象台的太阳直射表观测资料,反演得到了 1990—1993年北京大气柱气溶胶光学厚度,分析了该光学厚度月与年变化规律以及1991年菲律宾皮纳图博火山爆发对北京大气气溶胶含量的影响。本文还提出了关于有效水汽含量的一个经验关系式,用于确定水汽对太阳辐射的吸收率。 相似文献
120.