NURE航空计划回顾与新时代航空γ能谱勘查启示     

李敬敏  米耀辉  骆遥 《物探与化探》2021,(2):394-402

国家铀资源评价(NURE)计划实现了覆盖美国本土和阿拉斯加的1∶250000 NTMS图幅航空γ能谱测量和航磁测量,通过简要回顾该计划历程,重点针对NURE中航空地球物理勘查(航空γ能谱和航磁测量),讨论了航空地球物理勘查中测量技术、数据处理及解释方法等。NURE航空测量在铀矿勘查和辐射环境评价、洲际航空地球物理编图等领域发挥了巨大作用,产生了意义深远的影响。在总结NURE航空测量经验和做法的基础上,针对我国航空γ能谱测量勘查现状,建议从国家层面进行顶层设计,尽快实施我国陆域范围内的航空γ能谱和航磁框架性测量,实现对我国陆域航空γ能谱测量全覆盖,建设具有中国特色的航空γ能谱测量与监测体系。  相似文献   

Estimating the crush zone size under a cutting tool in coal     

R. K. Zipf Jr.  Z. T. Bieniawski 《Geotechnical and Geological Engineering》1988,6(4):279-295

Summary As part of an effort to understand the mechanics of fine fragment formation in coal, which is important in studies of respirable dust due to mining, fracture toughness measurements and the strain energy density (SED) theory were applied to calculate the crush zone size under a cutting tool in coal. This zone is the major source of fine fragments in the 1 to 10 µm size range. The model used in these calculations is a boundary element program containing a failure criterion based on the SED theory. The boundary element program calculates linear elastic stresses at numerous points in the coal material ahead of a cutting bit. These stresses are then input to a subroutine called critical flaw length and orientation (CFLO) which uses the SED theory to determine the CFLO for a small crack at the boundary element stress computation point. The extent of crushing is based on earlier postulates about the role of inherent flaws in a fragmentation process. To form 1 to 10 µm fragments requires firstly a local stress strong enough to activate flaws with a characteristic length less than 1 to 10 µm and secondly, a flaw density sufficient to provide an average spacing between flaws also on the order of 1 to 10 µm. The locus of active 10 µm flaws represents the maximum possible extent of fine fragmentation in the 10 µm or less size range assuming that a sufficient inherent flaw density exists. The approach offers a first order approximation to the extent of crushing under a tool tip. The size and shape of the crush zone volume is affected by the attack angle and geometry of the tool.  相似文献   

沉积体垂向层序的PC—1500袖珍计算机作图程序     

吴冲龙  程守田 《地球科学》1989,14(3):297-307

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晶体点阵参数最小二乘法计算程序     

陈蓉美 《湖南地质》1990,9(1):54-59

作者以最小二乘法理法导出了晶体点阵参数计算的公式,并顾及了X射线粉晶衍射图测定所引起的系统误差修正,从而得到点阵参数的最佳估值。以导出的公式为数学模型编制了PC-1500微机的扩展BASIC语言程序,可适用于各晶系点阵参数的计算,使用方便。  相似文献   

一种BASIC通用菜单驱动程序的设计     

许俊奇 《山西地震》1994,(2):47-51

在对ＣＣＤＯＳ汉字操作系统和ＢＡＳＩＣ语言特点的认真分析和处理后，得到了一个良好的通用菜单驱动程序，它完全可在不加改动或很少改动的情况下应用以汉字ＣＣＤＯＳ为操作系统的各种菜单驱动程序中。  相似文献   

Geothermobarometry of mafic granulites and metapelite from the Palghat Gap, South India: petrological evidence for isothermal uplift and rapid cooling   总被引：1，自引：0，他引：1  

C. R. RAVINDRA. KUMAR  T. CHACKO 《Journal of Metamorphic Geology》1994,12(4):479-492

The Palghat Gap region is located near the centre of the large southern Indian granulite terrane. at the northern edge of the Kodaikanal charnockite massif. The dominant rock types in the region are hornblende-biotite ± orthopyroxene gneisses and charnockites along with minor amounts of intercalated mafic granulite, metapelite and calc-silicate. The P-T estimates from garnetiferous mafic granulites and metapelite samples are generally in the range 9-10 kbar and 800-900 C using both conventional thermobarometric methods and the TWEEQU thermobarometry program. These P-T estimates, which should be taken as minimum values, are among the highest yet reported for South Indian and Sri Lankan granulites. The occurrence of orthopyroxene + plagioclase symplectites around embayed garnet grains in the mafic granulites and cordierite rims around garnet grains in metapelite suggest an isothermal decompression-type path. Similarly, a core-rim P-T trajectory indicates c. 3 and 7 kbar decompression at high temperature in the mafic granulites and metapelite, respectively. In both rock types, the key to the determination of the retrograde P-T path was the recognition of small amounts of second generation plagioclase with a more anorthitic composition than the matrix plagioclase. The preservation of high garnet-pyroxene temperatures in the mafic granulites (despite small garnet grain size) suggests rapid cooling of the terrane. Calculated minimum cooling rates range from 8 to 80 C Ma^-1. Such cooling rates are more rapid than those associated with normal isostatic processes and suggest that the terrane was tectonically exhumed at high temperature.  相似文献   

菲涅耳积分计算公式及其应用     

曹庆源 《武汉大学学报(信息科学版)》1986,(2)

菲涅耳积分是物理光学、微波技术与天线等多学科共用的特殊函数,其形式为上限可变而又不能积出的两个定积分,通常将其按变量u的不同区间分别用正或负幂级数计算。本文在原有公式的基础上研究出了简单、精密且变量复盖实数域的计算公式及其计算机程序。内容包括:(1) 最佳分区点u_1的选择;(2) u≤u_t时菲涅耳积分的变比级数表达式;(3) u>u_1时菲涅耳积分的三角函数表达式;(4)程序流程图;(5) 抽样运行数据及检验结果。  相似文献   

地层压力和大直径套管抗挤压力计算   总被引：2，自引：0，他引：2  

张平占  叶礼明 《煤田地质与勘探》1995,23(1):62-66

介绍了上覆地层压力和粘土吸水膨胀对套管挤压以及大直径管受外挤力失稳破坏的计算方法。解决了现场遇到的实际问题。  相似文献   

中酸性火成岩岩石化学计算若干问题的讨论及解决方案   总被引：1，自引：0，他引：1  

叶瑛 《岩石学报》1987,3(3)

对于中酸性火成岩,CIPW标准矿物与岩石实际矿物成分之间的差别是明显的。为了缩小这一差別,作者讨论了和岩石化学计算有关的若干问题,在此基研上提出了适用于中酸性火成岩的岩石化学计算方案。计算实例表明,本文方案能够弥补CIPW标准矿物分子法的某些不足。  相似文献   

地震定位研究及应用综述   总被引：10，自引：1，他引：10  

杨文东  金星  李山有  马强 《地震工程与工程振动》2005,25(1):14-20

地震定位是地震学中最经典、最基本的问题之一，提高定位精度也一直是地震学应用研究的重要课题之一。本文就目前各种地震定位方法进行了大体分类并概述了基本原理及其应用，介绍了目前在国内各实时地震观测系统中应用的台网定位方法，同时将部分台网方法应用于黑龙江省绥棱爆破的定位。  相似文献