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631.
研究区位于额尔古纳地块的额木尔山中间隆起带东部边缘塔河过渡带内,砂金资源极为丰富,成矿条件十分优越,具有良好的找矿远景.通过对区内地层、岩浆岩、构造、地球物理、地球化学、遥感等综合信息进行分析,初步总结了区内成矿规律,指出找矿的有利部位,并对区内找矿关键作了简单探讨,为区内下步找矿工作取得突破性进展提供了一定的思路. 相似文献
632.
遥感图像相关性及其熵计算 总被引:3,自引:0,他引:3
针对新一代遥感图像辐射分辨率提高的情况,设计了计算双字节联合熵的算法,讨论了量化级数对信息熵计算的影响,并考虑信源的记忆性质,对多波段图像讨论削减像元之间相关性及多波段间相关性的方法,进而对接近无记忆信源的图像数据进行联合熵的计算和分析,取得更为合理的评价结果.所发展的方法适用于多波段影像融合中最适宜的波段选择和质量评估. 相似文献
633.
634.
Recent Development in Simultaneous Multi-Element Determination of the Platinum Group Elements and Gold in Geological and Environmental Samples 总被引:1,自引:0,他引:1
In recent years, the modern methods of multi-element analysis of precious metals have attracted wide attention in scientific research and industry. The application and development in the decomposition of samples, separation and enrichment, and modern instrumental analysis of the platinum-group elements (PGEs) and gold in geological and environmental samples have been reviewed. Finally, the tendency of analysis of precious metals is also prospected. 相似文献
635.
This paper presents an effective optimization technique for the elastic and inelastic drift performance design of reinforced concrete buildings under response spectrum loading and pushover loading. Attempts have been made to develop an automatic optimal elastic and inelastic drift design of concrete framework structures. The entire optimization procedure can be divided into elastic design optimization and inelastic design optimization. Using the principle of virtual work, the elastic drift response generated by the response spectrum loading and the inelastic drift response produced by the non‐linear pushover loading can be explicitly expressed in terms of element sizing design variables. The optimization methodology for the solution of the explicit design problem of buildings is fundamentally based on the Optimality Criteria approach. One ten‐story, two‐bay building frame example is presented to illustrate the effectiveness and practicality of the proposed optimal design method. While rapid convergence in a few design cycles is found in the elastic optimization process, relatively slow but steady and smooth convergence of the optimal performance‐based design is found in the inelastic optimization process. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
636.
637.
滇西龙川江盆地中南部砂岩型铀矿成矿特征及成因探讨 总被引:2,自引:0,他引:2
研究了龙川江盆地中南部的沉积特征、构造特征及含矿岩系特征,提出铀成矿与构造演化中的2个沉积间断面关系密切。通过对龙川江盆地中南部铀矿化特征的研究,在382矿床内发现了沥青铀矿、铀黑和磷钙铀矿,在381矿床发现了超显微状放射性矿物,并根据龙川江盆地中南部382矿床成矿年龄的研究,提出了龙川江盆地中南部铀矿化的多阶段成因。 相似文献
638.
639.
Active faults in Quaternary unconsolidated sediments are important indicators to determine paleoearthquake events,They can be studied by macroscopic geological survey,but some problems have been encountered,such as invisible active faults.The authors found an approach to solve these problems by microstructural observation.Firstly,oriented original-state samples of Quaternary Unconsolidated sediments in active fault zones are collected.Secondly,the samples are consolidated in laboratory.Thirdly,microstructureal slides are gound in three-dimension coordinate system.Lastly,microstructures are observed in the microscopic field.By this method,the movement properties of active faults can be determined in lack of the support of macroscopic data.The invisible faults in Quaternary unconsolidated sediments can be found and described.The mechanisms of die-out faults can be also studied.oreover,the boundaries between different unconsolidated sediments in engineering sites can be studied to judge whether they are active faults or not. 相似文献
640.
Barry J. Katz Christopher G.A. Harrison Eugene H. Man 《Earth and Planetary Science Letters》1979,44(2):279-286
The “second region” of the kinetic curve for the racemization (epimerization) of isoleucine in foraminifera is defined from previously published data corrected for the thermal history experienced by the samples. These kinetic parameters are applied to racemization data from Deep Sea Drilling Project Sites 332A and 333 from the Deep Drill Valley, Mid-Atlantic Ridge, and Site 148 from the Aves Ridge, in order to determine whether there are any observable effects due to the geothermal gradient. The data for Site 148 clearly show an increase of temperature with depth. The data for the two sites of the Mid-Atlantic Ridge do not show this clear relationship. When bottom water temperature variations are taken into consideration, the effects of the geothermal gradient become apparent. Since the degree of racemization is dependent upon both age and temperature, a knowledge of the age of a sample places constraints upon its thermal history, and hence on the heat flow at the location since deposition of the sample. The crude heat flow models thus developed are compatible with present geologic and geophysical information. It appears probable that detailed heat flow models may be developed by improving analytical precision. 相似文献