A simple direct interpretation method for an electrical sounding carried out over an inclined interface     

T. Lee 《Pure and Applied Geophysics》1972,99(1):130-140

Summary The potential field due to a point electrode, above an inclined interface, has been given in the form of a multiple integral, involving modified Bessel functions of the second kind (Skalskaya [9]²). From this formula it is only possible to derive formulae, from which type curves may be computed, for a limited number of cases. By considering the asymptotic expansion of the Hankel transform of this potential function, it is possible to derive results which will permit the complete interpretation of a Schlumberger sounding, carried out in the direction of strike; for an arbitrary angle of dip of the contact. The method of interpretation is suitable for use on a digital computer and has been found to give rapid and reliable results.  相似文献   

Trace and platinum-group element geochemistry and the development of the Merensky unit of the Western Bushveld complex   总被引：2，自引：0，他引：2  

Lee  C. A. 《Mineralium Deposita》1983,18(2):173-190

Whole-rock samples of the Merensky Unit were analysed for major elements, Cu, Ni, Cr, Co, Eu, Th, U, Cs, and the platinum-group elements Pt, Pd, Rh, Ir and Au. There is a sympathetic variation of Cu, Ni, Co, and S throughout the sequence. Th and U abundances are highest around the Merensky Reef, and their distribution in the rest of the unit reflects the amount of mesostasis. Eu distribution is governed by primary plagioclase. Pt, Pd, Rh, Ir and Au (PM) are concentrated in the Merensky Reef. The relative proportions throughout the unit are Ir2 enrichment trends; interaction of these trends resulted in the Merensky Reef and its attendant mineralization.  相似文献   

Comments on ‘the Montsouris series of carbon dioxide concentration measurements, 1877–1910’, by G. Stanhill     

Lee S. Waterman 《Climatic change》1983,5(4):413-415

  相似文献   

Conditional analysis for petroleum resource evaluations     

P. J. Lee  P. C. C. Wang 《Mathematical Geosciences》1983,15(2):349-361

Conditional analysis is an essential component for evaluation of petroleum resources. Such analysis attempts to answer the questions: for the input data and a given play potential, what is the most likely number of pools and their sizes? An example is provided to illustrate the usage and application of this conditional method of analysis. This example demonstrates that the method can be used as a feedback mechanism to challenge the underlying geological concepts of the play; and to yield more certain predictions if additional information is given. Consequently, the method will enhance the reliability of the estimates of petroleum resources.  相似文献   

弯曲溢洪道挑流消能试验研究          下载免费PDF全文

李瑶  杨胜发  付旭辉 《水科学进展》2020,31(3):413-421

为避免加剧弯曲溢洪道的不良振动,对弯道水流的挑流消能问题进行研究。通过试验研究的方法,提出了一种适用于弯曲溢洪道的新型挑流消能工,结合渠底超高法对弯道水流的干扰,使水流在质量力的作用下分流,有效降低和减小了回水的流量范围,增加了挑流水舌的纵向长度。通过对比两种不同凹岸边墙半径的弯曲束窄差动式斜切挑坎和弯曲连续斜切挑坎的回流、挑流和分流等特性,根据水流运动特性和流线的几何关系,提出了一种判断该新型挑坎发生回水的半理论半经验方法。研究发现高坎的收缩程度和凹岸边墙半径是影响分流和回水的主要因素,通过对高坎水流运动特性的分析,拟合流量、凹岸边墙半径与高坎折冲水流出流方向角γ的经验公式,推导了高坎分流临界角度γc的计算表达式,计算结果与试验测量结果吻合良好,可以为弯道水流挑流消能的工程应用和运行提供参考。  相似文献   

Evaluation of acid-producing sulfidic materials in Virginia highway corridors     

Zenah?W.?OrndorffEmail author  W.?Lee Daniels 《Environmental Geology》2004,46(2):209-216

Road construction through sulfidic materials in Virginia has resulted in localized acid rock drainage (ARD) that threatens water quality, sedimentation, integrity of building materials, and vegetation management. Geologic formations associated with acid roadcuts were characterized by potential peroxide acidity (PPA), expressed as calcium carbonate equivalence (CCE), and total sulfur (total-S) in order to develop a statewide sulfide hazard rating map. The geologic formations were grouped into four categories based on potential acid-producing severity: i) Tabb formation (PPA<6 Mg CCE/1000 Mg; S<0.2%); ii) Ashe formation (PPA<18 Mg CCE/1000 Mg; S<2.0%); iii) Chesapeake Group, Lower Tertiary deposits, Millboro shale, Marcellus shale, and Needmore Formation (PPA<60 Mg CCE/1000 Mg; S<2.6%), and; iv) Chattanooga shale and Quantico slate (PPA<99 Mg CCE/1000 Mg; S<3.9%). Sulfide hazard analysis should be an essential step in the pre-design phase of highway construction and other earth-disturbing activities.  相似文献   

Endocrine disrupting alkylphenols and bisphenol-A in coastal waters and supermarket seafood from Singapore   总被引：2，自引：0，他引：2  

Basheer C  Lee HK  Tan KS 《Marine pollution bulletin》2004,48(11-12):1161-1167

  相似文献   

Pilot-scale field model tests for detecting landfill leachate intrusion into the subsurface using a grid-net electrical conductivity measurement system     

Myoung?Hak?Oh  Ju?Hyung?Lee  Gil?Lim?Yoon  Junboum?ParkEmail author 《Environmental Geology》2003,45(2):181-189

The grid-net electrical conductivity measurement system for detecting exact locations of landfill leachate intrusion in the subsurface was developed in this study. Laboratory and pilot-scale field model tests were performed to evaluate the direct application of a grid-net electrical conductivity measurement system for the detection of landfill leachate. A significant increase in electrical conductivity of soil was observed by adding landfill leachate. This can be explained as an increase in electrical conductivity of pore fluid due to an increase in leachate constituents as charge carriers. In pilot-scale field model tests, leachate intrusion locations were accurately identified at the initial stage of landfill leachate release by the grid-net electrical conductivity measurement system. The electrical conductivity of the subsurface before leachate injection lay within a small range of 24.8–43.0 S/cm. The electrical conductivity values in detected points were approximately ten times more than the conductivity values of the subsurface without landfill leachate intrusion. The results in this study indicate that the grid-net electrical conductivity measurement method has a possible application for detecting locations of landfill leachate intrusion into the subsurface at the initial stage, and thus has great potential in monitoring leachate leakage at waste landfills.  相似文献   

Use of an artificial neural network for analysis of the susceptibility to landslides at Boun,Korea   总被引：13，自引：0，他引：13  

Saro?LeeEmail author  Joo-Hyung?Ryu  Moung-Jin?Lee  Joong-Sun?Won 《Environmental Geology》2003,44(7):820-833

The purpose of this study was to develop landslide susceptibility analysis techniques using artificial neural networks and to apply the resulting techniques to the study area of Boun in Korea. Landslide locations were identified in the study area from interpretation of aerial photographs and field survey data. A spatial database of the topography, soil type, timber cover, geology, and land cover was constructed and the landslide-related factors were extracted from the spatial database. Using these factors, the susceptibility to landslides was analyzed by artificial neural network methods. The results of the landslide susceptibility maps were compared and verified using known landslide locations at another area, Yongin, in Korea. A Geographic Information System (GIS) was used to analyze efficiently the vast amount of data and an artificial neural network turned out to be an effective tool to analyze the landslide susceptibility.  相似文献   

Long-term change in eelgrass distribution at Bahía San Quintín,Baja California,Mexico, using satellite imagery     

David?H.?WardEmail author  Alexandra?Morton  T.?Lee?Tibbitts  David?C.?Douglas  Eduardo?Carrera-González 《Estuaries and Coasts》2003,26(6):1529-1539

Seagrasses are critically important components of many marine coastal and estuarine ecosystems, but are declining worldwide. Spatial change in distribution of eelgrass,Zostera marina L., was assessed at Bahía San Quintín, Baja California, Mexico, using a map to map comparison of data interpreted from a 1987 Satellite Pour l'Observation de la Terre multispectral satellite image and a 2000 Landsat Enhanced Thematic Mapping image. Eelgrass comprised 49% and 43% of the areal extent of the bay in 1987 and 2000, respectively. Spatial extent of eelgrass was 13% less (−321 ha) in 2000 than in 1987 with most losses occurring in subtidal areas. Over the 13-yr study period, there was a 34% loss of submerged eelgrass (−457 ha) and a 13% (+136 ha) gain of intertidal eelgrass. Within the two types of intertidal eelgrass, the patchy cover class (<85% cover) expanded (+250 ha) and continuous cover class (≥85% cover) declined (−114 ha). Most eelgrass losses were likely the result of sediment loading and turbidity caused by a single flooding event in winter of 1992–1993. Recent large-scale agricultural development of adjacent uplands may have exacerbated the effects of the flood. Oyster farming was not associated with any detectable losses in eelgrass spatial extent, despite the increase in number of oyster racks from 57 to 484 over the study period.  相似文献