地热井钻进岩屑录井技术方法探讨   总被引：1，自引：0，他引：1  

胡凌志  郑国海 《城市地质》2007,2(3):48-50

深井牙轮钻进不取芯的岩屑录井,是一项技术性很强的工作,关系到能否采全、采准深井岩层资料和标本。本文根据我院近年来地热井施工实践,总结出一套较为成型的录井技术方法,供从事此项工作的技术人员参考。  相似文献   

Alkylbenzenes in mussels from South and South East Asian coasts as a molecular tool to assess sewage impact     

Tsutsumi S  Yamaguchi Y  Nishida I  Akiyama K  Zakaria MP  Takada H 《Marine pollution bulletin》2002,45(1-12):325-331

Alkylbenzenes, molecular markers of sewage, were measured in 34 green mussels collected from India, Indonesia, Malaysia, Thailand, Cambodia, Vietnam, and the Philippines together with blue mussels collected from Tokyo Bay, Japan. Linear alkylbenzene (LAB) concentrations in South and South East Asian countries ranged from 10 to 1640 ng-∑LAB/g-dry tissue. In some populous cities, LAB concentrations were similar or higher than those found in northern Tokyo Bay which is heavily impacted by sewage effluents. I/E ratios (a ratio of internal to external isomers of LABs) in the South and South East Asian countries (1–3) were much lower than those in Tokyo Bay (3–8), indicating sewage discharged in the coastal zone is poorly treated (e.g., raw sewage and/or primary effluents). Alkylbenzenes with branched alkyl chains, tetrapropylene-based alkylbenzenes, were also detected in mussels from Indonesia and Philippines. This “tell-tale” sign indicates that poorly degradable detergents are still in use in this area, although they have long been phased-out in many industrialized countries.  相似文献   

Total and pyrogenic carbon stocks in black spruce forest floors from eastern Canada     

《Organic Geochemistry》2015

Pyrogenic carbon (PyC), a by-product of recurrent boreal wildfires, is an important component of the global soil C pool, although precise assessment of boreal PyC stock is scarce. The overall objective of this study was to estimate total C stock and PyC stock in forest floors of Eastern Canada boreal forests. We also investigated the environmental conditions controlling the stocks and characterized the composition of the forest floor layers. Forest floor samples were collected from mesic black spruce sites recently affected by fire (3–5 yr) and analyzed using elemental analysis and solid state ¹³C nuclear magnetic resonance (NMR) spectroscopy. PyC content was further estimated using a molecular mixing model. Total C stock in forest floors averaged 5.7 ± 2.9 kg C/m² and PyC stock 0.6 ± 0.3 kg C/m². Total stock varied with position in the landscape, with a greater accumulation of organic material on northern aspects and lower slope positions. In addition, total stock was significantly higher in spruce-dominated forest floors than stands where jack pine was present. The PyC stock was significantly related to the atomic H/C ratio (R² 0.84) of the different organic layers. ¹³C NMR spectroscopy revealed a large increase in aromatic carbon in the deepest forest floor layer (humified H horizon) at the organic-mineral soil interface. The majority of the PyC stock was located in this horizon and had been formed during past high severity fires rather than during the most recent fire event.  相似文献   

GM trees on trial in a field: Reductionism, risks and intractable biological objects     

Helena Valve 《Geoforum》2011,42(2):222-230

Identification of GM plants with their internal molecular-genetic qualities serves transformation of living organisms into identifiable commodities and objects of regulation. From molecular reductionist assumptions it also follows that scientific research is to be based on experiments that allow analysis of genetic influence in isolation. In this paper, I analyse molecular reductionism ‘in action’ by means of an ethnographic case study, focusing on the practices and transformations through which a field trial of transgenic trees created understanding of the risks or risklessness of the trees. The results show how the mobilisation of the field trial design, choosing of key analytical scales and formation of the research team stabilised the paths that experimentation was to follow. The scientists took the emerging inconsistencies and surprises calmly, indicating that unexpected events are an essential part of a scientific process. However, surprises could matter only in relation to the testing arrangements. Therefore, what could become visible and what could make a difference for the constitution of risk/risklessness were the fluctuations that the particular analytical assemblages defined as significant from the outset. Meanwhile, it was impossible to treat the trees and the field ecosystem as mutually constitutive. Nevertheless, there is no reason to think of knowledge production concerning transgenic organisms in deterministic terms. First, scientists are bound to be complexly engaged with the ecosystems that they are supposed to sort out. Second, consideration of the public lessons of experiments may elicit problems and limitations of molecular reductionism.  相似文献   

Simulation of structural phase transition in NaNO3 and CaCO3     

Jianjun Liu  C.-G. Duan  M. M. Ossowski  W. N. Mei  R. W. Smith  J. R. Hardy 《Physics and Chemistry of Minerals》2001,28(8):586-590

 The order-disorder phase transitions in NaNO₃ and CaCO₃ are simulated by molecular dynamics. The simulations are based on the potentials calculated from the Gordon–Kim modified electron gas formalism extended to molecular ions. We successfully reproduced the transition temperature T _c and the abnormally large c axis thermal expansion observed in experiment. The phase transitions in NaNO₃ and CaCO₃ were found to be initiated by ±60 and ±180° reorientation of the NO₃ and CO₃ ions about the c axis. The orientations of NO₃ and CO₃ ions are continuous with six preferred calcite-type orientations above the phase-transition temperature. Received: 30 January 2001 / Accepted: 11 May 2001  相似文献   

土壤水溶性有机物吸着系数及其影响因素研究   总被引：1，自引：1，他引：1  

张甲珅  曹军  陶澍 《地理科学》2001,21(5):423-427

测定了中国中、东部地区17种土类45个表土样品中水溶性有机物的吸着系数、分子量分布、腐殖酸含量、粘土含量以及土壤pH值，分析了水溶性有机物吸着系数的分布、地域分异和影响吸着系数的主要因素。结果表明，中国中、东部主要天然土壤类型A层水溶性有机物吸着系数在0．0014－0．0284L/g，中位数为0．0062L/g；研究区吸着系数具有自北向南和自西向东递降的一般趋势。水热的地域分异是影响土壤A层Ks地域分异的根本因素，pH和WSOC分子量分布是直接影响Ks值的两个重要因素。  相似文献   

利用煤矸石合成4A分子筛初探   总被引：4，自引：0，他引：4  

顾炳伟 《江苏地质》1997,21(2):90-92

利用煤矸石经煅烧后在强碱作用下制备成４Ａ分子筛，这一实验室成果对综合利用煤矸石、生产适于洗涤剂配方用的合成沸石分子筛，具有积极的意义。  相似文献   

Electronic and magnetic structure of vivianite: cluster molecular orbital calculations     

M. Grodzicki  G. Amthauer 《Physics and Chemistry of Minerals》2000,27(10):694-702

The electronic and magnetic structure of the octahydrophosphate vivianite, Fe₃(PO₄)₂·8H₂O, has been investigated by cluster molecular orbital calculations in local spin density approximation. Optical and Mössbauer spectra are well reproduced by the calculations, and the differences between the two iron sites can be correlated with differences in the geometrical structure of the first coordination sphere. The spin structure within the crystallographic ac plane is derived and explained on the basis of different superexchange pathways via edges of the phosphate tetrahedra. The calculations demonstrate that quite large clusters (up to 118 atoms) are necessary to arrive at reliable results.  相似文献   

CaCO₃生物矿化的研究进展——有机质的控制作用   总被引：9，自引：0，他引：9  

张刚生  谢先德 《地球科学进展》2000,15(2):204-209

生物CaCO₃是自然界分布最广泛的一类生物矿物,其组成除了无机相的CaCO₃外,还含有少量的有机质,包括水可溶(SM)和水不可溶有机质(IM),SM富含阴离子基团,是控制CaCO₃结晶的重要因素之一。通过有机—无机界面分子识别,有机质选择性地与CaCO₃晶体特定方向的面网相互作用,从而对CaCO₃的生长、形貌、多型及结晶学定向等产生明显的控制作用。有机—无机界面的分子识别机制包括静电、晶格几何匹配和立体化学互补等。仿生矿化的研究为进一步深入了解生物矿化的机理及制造高级复合材料提供了新的方法。  相似文献   

氩同位素分馏的实验研究   总被引：3，自引：0，他引：3       下载免费PDF全文

刘强  朱铭  张福松  霍卫国  刘嘉麒 《地质科学》2000,35(3):297-304

尽管⁴⁰Ar和36Ar之间质量相差达1/10,但是受放射性成因⁴⁰Ar的影响,一般认为难以进行氩同位素分馏研究.本文通过自行设计的一套氩扩散迁移实验分析系统,对比研究了氩在不同的扩散介质条件下扩散迁移前后氩同位素组成变化情况,证实氩在致密的扩散介质条件下以分子流形式从一个储库向另一个储库的迁移过程中,由于36Ar和⁴⁰Ar的迁移速率不同,扩散后的⁴⁰Ar/36Ar值比扩散前的值要小,也即发生了氩同位素分馏.氩同位素分馏的特征表现为最初的一段时间内分馏程度逐步增强,在一定时间后,由于储库之间压力逐渐达到平衡,分馏程度逐步减小.研究自然界中存在的氩同位素分馏,不仅可以判别油气田中油气运移的方向、增强油气远景评价和地球化学勘探,而且对深源岩浆的起源、迁移等研究也可提供新的研究思路和途径.  相似文献