远东地区f₀E_s剧增与K指数突变的关系          下载免费PDF全文

谭子勋 《地球物理学报》1988,31(2):225-230

一、前言 中纬度地区电离层E_s的成因与影响因素是一复杂的问题。远东地区E_s既多又强,其它电离层现象也有一些特色,本文在文献[9]的基础上,从分析原始频高图入手,对远东地区夜间f₀E_s剧增与地磁K指数的关系作了统计研究,发现两者之间关系甚为密切,即地磁K指数的突然变化伴随着夜间E_s层临界频率f₀E_s的剧烈增加。  相似文献   

滇西澜沧变质带中白云母的研究及其地质意义   总被引：7，自引：0，他引：7       下载免费PDF全文

赵靖 《岩石矿物学杂志》1993,(3)

本文以滇西澜沧变质带中最为广泛分布的造岩矿物——白云母为对象,详细研究和分析了其成分、多型类型及b_0值等,探讨了白云母的发育规律。研究结果表明,本带中绝大多数白云母为多硅白云母,且为3T+2M_1型,与蓝闪石共生的则以3T多硅白云母为主。此外,澜沧变质带经历了蓝闪石片岩亚相的高压变质作用,与古特提斯构造演化密切相关,并可与世界著名的高压带对比。  相似文献   

数字河流数据的自动综合   总被引：2，自引：0，他引：2  

武芳 《测绘学院学报》1994,(1)

本文主要介绍了数据库中水系要素综合中河流的自动综合方法，尤其是对非结构化河网中河流的自动选取作了较为详细的论述，并通过数据库中一幅完整图幅的河流数据对文中介绍的自动综合方法进行了验证。  相似文献   

电阻率-孔隙度、电阻率-含油（气）饱和度关系的一般形式及其最佳逼近函数类型的确定（Ⅰ）   总被引：4，自引：0，他引：4       下载免费PDF全文

李宁 《地球物理学报》1989,32(5):580-592

本文导出了电阻率-孔隙度、电阻率-含油（气）饱和度关系的一般形式--两个对称的表达式,并给予了实验证明。同时,本文指出,Archie公式、Winsauer公式和双水公式都是一般形式在一定条件下的特例。在一般情况下,本文给出了14个能够逼近这两个表达式的函数类型,通过岩芯数据进行选优,可以得到适合不同地区或地层的最优方程。根据本文理论建立的解释方法和研制的软件已经在油田生产中推广应用并取得了良好效果。 由于涉及内容较多,全文分两部分撰写。以下是本文的第（Ⅰ）部分,即一般形式的导出及实验验证;而最佳函数类型的确定及其在生产中的应用将作为本文的第（Ⅱ）部分发表。  相似文献   

(Re) deposition of loess in southern Limbourg,the Netherlands 3. Field evidence for conditions of deposition of the middle and upper silt loam complexes,and landscape evolution at Nagelbeek     

W. J. Vreeken 《地球表面变化过程与地形》1984,9(1):1-18

This paper is about conditions and processes during the accumulation of the Upper Pleniglacial Middle and Upper Silt Loam complexes at Nagelbeek, Limbourg, a Weichselian stratigraphical type locality. The complexes correlate with Hesbayan and Brabantian loesses in Belgium, formed between 28,000 and 12,400 yrs BP. They are characterized by sediment features (cracks, mass deformations, and cut-and-fill features) that are ascribed to a cryogenic regimen. The main Middle Silt Loam subunit contains contraction cracks deformed and further modified by masswasting. Intra-Upper-Pleniglacial pedogenic intervals are inferred from three greyish bands, from a truncated weathered zone surmounting the Middle Silt Loam, and from an aeolian-cumulic palaeosol at the base of the Upper Silt Loam. Latter two zones and an intervening erosional unconformity were cryogenically reworked, less than 22,000 yrs BP, to form a complex stratigraphical marker-zone: the ‘Horizon à Langues de Nagelbeek’. Morphological variants of the marker-zone are described. The geomorphic evolution of the Nagelbeek upland, from Saalian to Holocene times, is summarized in unconformity maps and a time diagram.  相似文献   

Further Studies Of Atmospheric Turbulence In Layers Near The Surface: Scaling The Tke Budget Above The Roughness Sublayer   总被引：2，自引：0，他引：2  

Paul Frenzen  Christoph A. Vogel 《Boundary-Layer Meteorology》2001,99(2):173-206

The second of two experimental studies of the TKE budget conducted on sites of different roughness is described, and results are compared. The first took place within a shallow layer above a small field of mostly bare, cultivated soil; the second was carried out above a roughness sublayer of significant depth on an extensive plain of tall dry grass. Budget terms observed in the second study were scaled with a modified u which compensated for effects of an unusually large stress gradient and ensured that the _m functions would be collinear. By showing that the modification becomes negligible in smaller gradients, it is demonstrated that in normal conditions, budgets observed above significant roughness sublayers should be normalized by scaling in terms of the unreduced Reynolds stress at the sublayer's upper surface. This procedure is shown to be consistent with the expectation that TKE budgets in layers near the surface all scale in fundamentally the same way.Other findings include: (1) the fact that most _m functions previously reported are not quite collinear is attributed to a type of overspeeding known to affect three-cup anemometers; (2) revised _m functions, collinear and largely free of the effects of overspeeding, are determined from a well-established characteristic of the linear _m relation for the stable case; (3) data that define collinear _m functions can also be represented with single hyperbolic curves; (4) dissipation is found to be 10 to 15% too small to balance total TKE production in unstable and neutral conditions and to decrease with increasing z/L in thestable regime; and (5) new relations for based on the observed behaviour of the dissipation deficit provide an improved closure for the set of equations that express the budget terms as functions of _m and z/L.  相似文献   

Comparison between Pollutant Concentration in the Samples of Fog and Rime Water Collected at Mt. Milešovka     

Fišák  Jaroslav  Řezáčová  Daniela 《Studia Geophysica et Geodaetica》2001,45(3):319-324

The article aims at showing the differences in concentration of pollutants that are contained in the samples of fog and/or low cloud water in comparison with the water from rime. The results follow from the fog and rime measurements made at Mt. Mileovka (eské Stedohoí Mountains). They are compared with the results of other studies that also report the differences in fog and rime chemistry.  相似文献   

河北省蔚县矿区构造特征及断裂构造发育规律     

郭增昌  徐世陆等 《中国煤田地质》2002,14(4):9-11

运用现代构造地质研究方法，对蔚县矿区构造特征及断裂构造发育规律进行了研究。并揭示了矿区构造成因机制及演化历史。  相似文献   

长沙—澧陵—浏阳—带冷家溪群及板溪群的甚低级变质作用   总被引：13，自引：5，他引：13  

朱明新  王河锦 《岩石学报》2001,17(2):291-300

湘东长沙-澧陵-浏阳一带中晚元古宇的冷家溪群及板溪群遭受了区域甚低级变质作用.在本地区所采的＜2μm的样品中,冷家溪群伊利石结晶度的Kübler指数为0.18～0.26°△2θ,板溪群为0.21～0.28°△2θ(Kisch国际标样校正).从而可把本地区冷家溪群的区域变质划归浅变质带和近变质带上部,温度大约为280～400℃.板溪群划归近变质带上部,温度大约为250～300℃.并未普遍达到目前人们认为的绿片岩相或者是低绿片岩相.样品中冷家溪群伊利石(白云母)b0值的范围在0.8999～0.9042 nm,板溪群为0.9018～0.9042nm.由冷家溪群b0频率累积曲线图,得出本区冷家溪群处于较典型的中压区.  相似文献   

When are relative variograms useful in geostatistics?     

Noel Cressie 《Mathematical Geology》1985,17(7):693-702

The relative variogram has been employed as a tool for correcting a simple kind of nonstationarity, namely that in which local variance is proportional to local mean squared. In the past, this has been linked in a vague way to the lognormal distribution, although if {Z_t; t D}is strongly stationary and normal over a domain D,then clearly {exp (Z_t); t D}will stillbe stationary, but lognormal. The appropriate link is made in this article through a universal transformation principle. More general situations are considered, leading to the use of a scaled variogram.  相似文献