瞬变电磁法(TEM)和激发极化法在金矿勘探中的应用     

汤良明  罗华华  汪玉琼 《贵州地质》2007,24(3):212-214

本文简述了脉冲瞬变电磁法(TEM)和激发极化法在贵州×××金矿勘探中的综合应用。介绍了TEM瞬变电磁法、激发极化法原理、工作仪器及工作中所采用参数及资料整理中所有分析解释软件,选择了黄泥堡金矿10线TEM剖面、激电剖面作为实例进行异常解释推断并结合电测深及钻孔资料对异常进行了验证。  相似文献   

Geophysical investigations of buried Quaternary valleys in Denmark: an integrated application of transient electromagnetic soundings, reflection seismic surveys and exploratory drillings   总被引：1，自引：0，他引：1  

Flemming Jrgensen  Holger Lykke-Andersen  Peter B. E. Sandersen  Esben Auken  Egon Nrmark 《Journal of Applied Geophysics》2003,53(4):215

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大气降尘TEM观察及其环境矿物学意义   总被引：10，自引：5，他引：10       下载免费PDF全文

陈天虎  徐惠芳 《岩石矿物学杂志》2003,22(4):425-428

在X射线衍射等分析研究基础上，进一步用透射电镜对半封闭室内长期沉积的大气降尘进行观察，提供了合肥地区大气降尘物相组成和各种物相形貌特征信息，揭示合肥地区大气污染物来源占第1位的是地表扬尘，以粘土矿物为标志；占第2位的是来源于大气化学次生气溶胶，主要和SO2、CO2、NOx等气态污染物排放有关，以石膏、碳酸盐和易溶盐类为标志；占第3位的是来源于汽车尾气排放的烟尘，以炭球为标志；占第4位的是来源于燃煤烟尘排放，以球形玻璃珠为特征。TEM调查不仅为合肥地区大气气溶胶颗粒成因、城市大气污染物来源和污染控制对策提供准确资料和依据，而且为确定大气颗粒物来源提供了有效研究方法和物源判别标志。  相似文献   

山东五莲碱性三元长石的微结构研究     

蔡元峰  周玲棣 《地质论评》1998,44(5):536-541

笔者对产于山东五莲县七宝山辉石二长岩中的碱性长石进行了电子探针,Ｘ射线衍射,透射电子显微镜以及＾２９ＳｉＭＡＳＮＭＲ谱研究,确定五莲碱性三元长石（Ｏｒ５０．３,Ａｂ４４．３Ａｎ５．４）为钾长石和钠长石共格出溶连晶,其基体钾长石为单斜对称,在透射电子显微镜下未见其呈现任何微结构,而在钠长石中见到宽度为１０．４ｎｍ（钠长石的８ｂ０）的片晶相互形成周期钠长石律双晶,钠长石叶片的宽度平均为３９ｎｍ（ｎ＝４  相似文献   

Behaviour of Fe-oxides relevant to contaminant uptake in the environment   总被引：6，自引：0，他引：6  

S. L. S. Stipp  M. Hansen  R. Kristensen  M. F. Hochella  Jr.  L. Bennedsen  K. Dideriksen  T. Balic-Zunic  D. Lonard  H. -J. Mathieu 《Chemical Geology》2002,190(1-4):321-337

The behaviour of Fe-oxides was investigated during precipitation and co-precipitation, phase transformation and dissolution, while their ability to adsorb and incorporate trace components was examined. Some samples were synthesised and studied under controlled laboratory conditions and other samples were taken from experiments designed to test the effectiveness of waste treatment strategies using iron. Surface-sensitive and high-resolution techniques were used to complement information gathered from classical, macroscopic methods.

Adsorption isotherms for Ni²⁺ uptake on synthetic ferrihydrite (Fe₅HO₈·4H₂O, often written simply Fe(OH)₃), goethite (-FeOOH), hematite (-Fe₂O₃) and magnetite (Fe₃O₄) were all similar, increasing as expected at higher pH. Desorption behaviour was also similar, but one third or more of the Ni²⁺ failed to return to solution. In the past, “irreversible sorption” has been blamed on uptake into micro-fractures or pores, but during examination (using Atomic force microscopy, AFM) of hundreds of Fe-oxide particles, no evidence for such features could be found, leading to the conclusion that Ni²⁺ must become incorporated onto or into the solids. When solutions of Fe(II) are oxidised in controlled laboratory conditions or during treatment of ash from municipal waste incinerators, two-line ferrihydrite forms rapidly and on never-dried samples, AFM shows abundant individual particles with diameter ranging from 0.5 to several tens of nanometers. Aging in solution at 70°C promotes growth of the particles into hematite and goethite and their identification (by X-ray powder diffraction, XRPD, with Rietveld refinement) becomes possible at the same aging stage as mineral morphology becomes recognisable by AFM. In other experiments that were designed to mimic natural attack by organic acids, colloidal lepidocrocite (γ-FeOOH) was observed in situ by AFM, while reductive dissolution removed material on specific crystal faces. Lath ends are eroded fastest while basal planes are more stable.

In order to help elucidate mechanisms of contaminant immobilisation by Fe-oxides, we examined samples from a reactive barrier made with 90% quartz sand, 5% bentonite and 5% zero-valent iron filings that had reacted with a solution typical of leachate from coal-burning fly ash using time-of-flight secondary ion mass spectroscopy (TOF-SIMS). Fe(0) oxidised to Fe(III), while soluble and toxic Cr(VI) was reduced to insoluble Cr(III). Chemical maps show Fe-oxide coatings on bentonite; Cr is associated with Fe-oxides to some extent but its association with Ca in a previously undescribed phase is much stronger. Other samples taken from municipal waste incinerator ash that had been treated by aeration in Fe(II) solutions were examined with transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectroscopy (EDS). Pb and some Zn are seen to be dispersed throughout two-line ferrihydrite aggregates, whereas Sn and some Zn are incorporated simply as a result of entrainment of individual ZnSn-oxide crystallites.

Geochemical speciation models that fail to account for contaminant uptake in solid solutions within major phases or as thin coatings or entrained crystals of uncommon phases such as those described here risk to underestimate contaminant retardation or immobilisation.  相似文献   

TEM中心回线法瞬变磁场求取和全区视电阻率计算   总被引：3，自引：0，他引：3  

许建荣  李爱勇  杨生 《地质与勘探》2008,44(6):62-68

依据TEM法中心回线装置瞬变电磁场的衰减规律,给出了由实测的dB/dt求取瞬变磁场B的简单方法.详细推导了发射电流为斜阶跃波条件下由B迭代反演全区视电阻率的方法.为提高计算精度和速度,对计算过程中的积分、求导推导了解析表达式和采用标准数据库的方法计算含有概率积分的函数.对实测资料进行了计算,通过算例进行了验证和分析.  相似文献   

激电-瞬变电法在那能金矿评价中的应用效果   总被引：1，自引：0，他引：1  

杨善乐  杨绍文 《云南地质》2008,27(3):376-382

选择采用1：5万土壤化学测量圈定异常确定找矿靶区,应用激电-瞬变电法对矿（化）体的空间分布进行准确定位,工程验证物探推断异常的普查工作程序。同时指出了物化探方法选择、技术方法要求及野外工作程序。  相似文献   

瞬变电磁法在地下水勘查中的应用综述   总被引：13，自引：3，他引：10  

张保祥  刘春华 《地球物理学进展》2004,19(3):537-542

水是地球上最重要的天然资源,供人类需要的淡水有95％以上取自地下水,地下水在人类经济活动中发挥着重要的作用．传统的地球物理方法在地下水勘查工作中得到应用的同时,新的更先进的物探方法不断涌现．近年来,瞬变电磁法在国内外的应用得到迅速发展,在地下水勘查领域的应用也得到拓展．与其它电探方法相比,利用瞬变电磁法进行地下水勘查具有明显优势。  相似文献   

帘文蛤精子超微结构及与其他双壳贝类的比较     

周小龙  董迎辉  边平江  林志华 《台湾海峡》2012,31(4):495-500

利用扫描电镜和透射电镜技术,详细观察了帘文蛤（Meretrix lyrata）精子的形态和超微结构.研究发现,帘文蛤的精子为典型的原生型,全长42.2±1.8μm,包括头部、中段和尾部三部分.头部为稍弯曲的狭茧形,长约2.4μm,由前端的顶体和其后的细胞核组成,顶体呈倒＂V＂形,前端电子密度较小,后端电子密度较大;核内含有高度浓缩的染色质,可见染色较浅的核泡存在,无核前窝,有明显核后窝和植入窝.中段由5个呈辐射状排列的线粒体和中央的2个相互垂直的中心粒复合体构成,线粒体近球形,由内、外两层膜组成.尾部鞭毛长39.3±1.9μm,由波浪状质膜和包裹其中的轴丝组成.另外,将帘蛤科（Veneridae）尤其是文蛤属（Meretrix）贝类精子超微结构与其他贝类进行了比较和分析,为文蛤属的种类鉴别提供细胞学依据.  相似文献   

大回线源瞬变电磁一维自适应反演方法及应用     

姚伟华 《物探与化探》2019,(3):584-588

提出了一种适用于大回线源瞬变电磁法框内任意测点垂直Z分量的一维反演方法。该算法采用CMD正则化因子优化方案、光滑度函数和自然边界条件对反演过程进行了约束,减小了初值的依赖度,保证了反演过程的自主性和反演结果的稳定性;在反演过程中,在保证模型残差沿梯度下降的同时,对模型修正量的最大值进行了限制,使反演模型不易陷入局部极小,保证了反演结果全局的收敛性;同时反演的灵敏度矩阵采用牛顿法进行更新,减少了整个反演计算的工作量。最后通过五层的双低阻层模型、双高阻层模型和实测资料证明了该算法可靠。  相似文献