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121.
矿物热电效应测试   总被引:1,自引:0,他引:1       下载免费PDF全文
李家驹 《地质科学》1973,8(4):317-326
1965年笔者曾简要地介绍过有关热电效应的基本概念,国外有关矿物热电效应研究及其在地质学中的应用。 近年笔者装配了一套热电效应测试仪器,先后对33种矿物共103块标本作了测试。现将测试设备及结果简介如下。  相似文献   
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123.
The presence of a conducting environment about a spherical ore body must be considered when calculating the transient electromagnetic response of the ore body due to a step current flowing in a large circular loop at the earth's surface. Failure to do this can easily lead to errors in excess of 10% in numerical calculations. Moreover, there is only a limited time interval in which the response of the spherical conductor is easily seen. In a poorly conducting ground the resonance response of the sphere is the first to be excited. Later, however, the non-resonance or wave-type response is excited. These waves destructively interfere and finally the response of the sphere decays with time as t?7/2. For a range of times and depths the best loop for detecting the sphere has about the same radius as the sphere.  相似文献   
124.
本文应用1956年6月到1957年5月一年内逐日亚欧500mb 天气图,计算历次高低压系统经过西藏高原以北时在强度和速度方面的改变,证明这些改变是有规则的,在地域上和季节上皆表现出独特性。  相似文献   
125.
杨鉴初  李玉兰 《气象学报》1959,30(4):297-305
本文用统计方法研究1930—1939年期间逐月北半球气压偏距中心的活动规律.发现同一月份的气压偏距中心在北半球某些地区有集中出现的情况,这些集中地区如在阿拉斯加的南方、大西洋的东北部以及亚欧大陆的北冰洋沿岸.这些地区可以认为是北半球环流异常的关鍵性地区.绝大多数的偏距中心在逐月之间可以发现它们的联系.在过渡季节,大多数偏距中心自西向东移动.在偏距中心相互作用的基础上,本文还讨论了北半球某些地区的气候特点.  相似文献   
126.
The development of optically pumped and monitored “atomic” magnetometers has allowed the application of greater resolution in geomagnetic measurements for exploration purposes. This paper presents a survey of instrumentation in use, the variety of exploration techniques that are being used in practice, and an estimate of their state of development. Alkali metals (rubidium and cesium) and helium have been used as active elements to obtain the magnetic-field dependent Larmor frequency. Each of these instruments is capable of obtaining high resolution data (data with sensitivity numerically smaller than one-tenth gamma). They have been adapted for airborne, land, and marine usage. Such sensitivity has enabled the rapid development of geomagnetic gradiometers, high sensitivity aeromagnetics, diurnally reduced ground surveys, broad-band magneto-telluric surveys, susceptibility measurements, and convenient magnetic search and location techniques. Outlines of each procedure and an example of its application are given.  相似文献   
127.
To recognize the geographical characteristics of the landslide areas will be helpful for the watershedmanagement in the reservoir watershed. According to the quantitative analysis, we'll take differentscores and weighting for the potential parameters of the landslide areas in the Tsengwen reservoirwatershed, and in the meanwhile, we'll extract the different factors, including the slope, aspect,altitude, soil and geological textures etc., and the results shown as maximum one--day rainfall, ratio offorests and average relief is the most affecting parameters on the potential risk map of landslide areas.  相似文献   
128.
Are human able to foresee the future? For thou-sands of years close attention has been paid to this issue. At the present day, in order to survive from competition and to predominate over the nature, hu-man抯 desire of forecasting things has become more and more intense. Compared to conquering space, more people yearn for being able to control the time. From ancient to the present, mankind always dream of contacting the past, governing the present and tran-scending the future. Recent years in…  相似文献   
129.
V/Sc systematics in peridotites, mid-ocean ridge basalts andarc basalts are investigated to constrain the variation of fO2in the asthenospheric mantle. V/Sc ratios are used here to ‘seethrough’ those processes that can modify barometric fO2determinations in mantle rocks and/or magmas: early fractionalcrystallization, degassing, crustal assimilation and mantlemetasomatism. Melting models are combined here with a literaturedatabase on peridotites, arc lavas and mid-ocean ridge basalts,along with new, more precise data on peridotites and selectedarc lavas. V/Sc ratios in primitive arc lavas from the Cascadesmagmatic arc are correlated with fluid-mobile elements (e.g.Ba and K), indicating that fluids may subtly influence fO2 duringmelting. However, for the most part, the average V/Sc-inferredfO2s of arc basalts, MORB and peridotites are remarkably similar(–1·25 to +0·5 log units from the FMQ buffer)and disagree with the observation that the barometric fO2s ofarc lavas are several orders of magnitude higher. These observationssuggest that the upper part of the Earth's mantle may be stronglybuffered in terms of fO2. The higher barometric fO2s of arclavas and some arc-related xenoliths may be due respectivelyto magmatic differentiation processes and to exposure to large,time-integrated fluid fluxes incurred during the long-term stabilityof the lithospheric mantle. KEY WORDS: vanadium; scandium; oxygen fugacity; mantle; arcs  相似文献   
130.
本研究系应用数字地球系统理论于中央山脉保育轴经营管理机制建置 ,并依 IUCN之保育区划设标准 ,作为未来研订中央山脉保育计划之分区准则与数字台湾系统建立之发展模式。数字台湾之观念乃源于数字地球突破传统信息空间、政策经营之多向度信息整合 ,同时考虑克服科技应用与时间效益以及决策兼蓄解决传统资源管理在空间地理与生态艺术上之综合性问题。  相似文献   
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