用于多频电磁波测井的负阻抗变换式有源接收天线     

刘海滨  佟文琪 《物探与化探》1997,21(1):58-61

本文对用负阻抗变换电路同小圆锥螺旋天线相结合,构成的有源接收天线进行了理论分析,并给出了该有源天线稳定工作的条件。结果表明,用该方法设计的有源接收天线具有较宽的频带、较高的灵敏度和较小的尺寸。是多频电磁波测井较理想的接收天线。  相似文献   

地气法－找深部金矿的新方法   总被引：4，自引：0，他引：4  

童纯菡  李晓林  李巨初  吴晓平 《物探化探计算技术》1996,(Z1)

介绍一种八十年代发展起来的找深部金矿的新方法一地气法。文中讨论了地气法的找矿机理，认为是地壳中上升气流将成矿元素微粒携带至地表而造成多元素异常。对工作方法着重讨论了地气采样与测试的系统，以及比较了积累式取样的效果。最后列出山东招远地区大尹格庄金矿８０号勘探线的地气测量多元素异常图。  相似文献   

碳酸盐岩地区电磁波场的特性分析     

刘海滨  佟文琪 《世界地质》1996,15(1):82-87

形成岩溶的高阻碳酸盐岩对电磁波的吸收较弱，而且成层沉积的特定环境使碳酸盐岩地区岩石的各向异性现象较明显，由于地空界面的存在及岩溶洞壁两侧介质电性差异明显，界面清晰，又使电磁波出现强烈的反射及散射现象，从理论上对碳酸盐岩地区电磁波传播的特有现象进行了研究和分析，并给出结论。  相似文献   

ADVANCES IN MEASURING TECHNIQUES OF BED LOAD     

ZHOU Gangyan ZOU Jiazhong 《国际泥沙研究》1997,(1)

I.m~UCrIONBedloadisthesedimentwhichmovesalongtheriverbedintheformofrolling,slidingandsaltation.BedloadmaycreatemanyproblemsintheoperationandmaintenanceofnavigationchannelandinthedevelOPmentofhydroelectricity.Dataofbedloaddischargearealsorequiredinthedesignofreservoir,inwhichtheinflowbedloadareallactuallytrapped.Thewaysofbedloadmotionaredifferentfordifferentsizes.Thus,itisextremelydifficulttodeterminethebedloaddischargeaccurately.Manyequationshavebeenproposedtocalculatethebedloaddischarge.H…  相似文献   

中国大陆岩石圈的化学元素丰度   总被引：32，自引：3，他引：32  

黎彤  倪守斌 《地质与勘探》1997,33(1):31-37

中国大陆岩石圈模型的面积９６０万ｋｍ＾２，平均厚度１１０ｋｍ，体积１０．６亿ｋｍ＾３，岩石平均密度３．０６４ｇ／ｃｍ＾３、总质量３．２４５×１０＾１８ｔ。在中国大陆地壳元素丰度的基础上，作者首次求出中国大陆岩石圈的元素丰度值。其质量丰度，厚子丰度和相对丰度列于表１。此外还按１０类（７８种）元素分别讨论中国大陆岩石圈的主要化学特征。  相似文献   

Sequence Stratigraphy of the Permian--Triassia Boundary Section of Changxing, Zhejiang, Southern China   总被引：1，自引：0，他引：1  

Zhang Kexin  Tong Jinnan  Yin Hongfu  Wu Shunbao China University of Geosciences  Wuhan  Hubei 《《地质学报》英文版》1997,71(1):90-103

Three third-order sequences and about one hundred high-frequency cycles or Milankovitchcycles within the Late Permian Changxingian to Early Triassic Griesbachian are identified in theMeishan Section of Changxing, Zhejiang Province, southern China, the candidate stratotype sec-tion of the global Permo-Triassic boundary, based on a detailed study of the biological,ecological and high-resolution allochthonous cyclic events, microfacies and depositional systems.Furthermore, the stacking pattern of the depositional systems across various Changxingian andGriesbachian sedimentary facies of the Lower Yangtze and the sequence stratigraphic frameworkare outlined with the Meishan section as the principal section. In this paper the habitat types offossil biota are applied to semiquantitative palaeobathymetry and the study of relative sea levelchanges.  相似文献   

地史转折期的生态系   总被引：7，自引：2，他引：7  

殷鸿福  童金南 《地学前缘》1997,(Z2)

生态系的演变是地球各圈层系统耦合关系变化的直接标志。地史转折期的生态系具有复杂的生物内涵，在绝灭—残存—复苏过程中，各生物类别的演替遵循着一定的生存型式。大绝灭后生态系复苏的原动力是绝灭后迁入避难所的复活类型和大绝灭末期高压环境中产生的祖先类型的新生和辐射发展。全面了解绝灭后生态系的组成和结构，对于正确认识地史转折期，即圈层耦合结点处的地质作用型式和过程具有重要作用。  相似文献   

陕西中南部的视应力场研究   总被引：2，自引：1，他引：2       下载免费PDF全文

王卫东  张永志  邵广周  刘国华  邹志伟  狄秀玲 《地震工程学报》2004,26(4):343-346

利用西安数字地震台网的宽频带数字地震记录，计算了陕西中、南部地震的视应力水平，并讨论了泾阳5．2级地震前后地震视应力的时间变化特征及视应力与震级的关系。  相似文献   

Study of charge structure and radiation characteristic of intracloud discharge in thunderstorms of Qinghai-Tibet Plateau     

ZHAGN Yijun  DONG Wansheng  ZHAO Yang  ZHANG Guangshu  Zhang Hongfa  CHEN Chengpin  ZHANG Tong 《中国科学D辑(英文版)》2004,47(Z1)

The comprehensive observations on lightning discharges were conducted in Naqu area of Qinghai-Tibet Plateau in summer of 2002. The electric structures of thunderstorms and the characteristics of lightning discharges at initial stage were analyzed by using the observation data. The results show that most of intracloud (IC) lightning flashes were polarities inverted in thunderstorms with tripole electric charge structure and occurred between negative charge region located in the middle of the thunderstorm and positive charge region located at the bottom of the thunderstorm. The radiation characteristics of discharge processes in cloud with longer lasting time involved in Cloud-to-Ground (CG) lightning flashes were similar to that of IC discharges.A lot of radiation pulses were produced in these discharge processes. Because the IC discharges took place at the bottom of thundercloud and were near the ground, they may produce more serious damage to equipment on the ground therefore should not be neglected in lightning protection.  相似文献   

Research on the effect estimation of seismic safety evaluation     

邹其嘉  陶裕禄 《地震学报(英文版)》2004,17(1):87-98

IntroductionItisdefinitelystipulatedintheLawofthePeople'sRepublicofChinaonProtectingagainstandMitigatingEarthquakeDisastersthattheseismicsafetyevaluationmustbemadeformajorprojects(includinglifelineprojects)and,accordingtotheresultsobtained,theseismicresistancerequirementsshouldbedetermined.Thenecessityofseismicsafetyevaluationhasbeenrecog-nizedgradually,butthetopicontheeffectofsafetyevaluationhasnotbeenreferredmuch.Gener-allyspeaking,althoughmostpeopleapprovethesocialeffectofsafetyevaluatio…  相似文献