Kinetics of the Reaction of Hydroxyl Radicals with CH2Br2 and its Implications in the Atmosphere     

Deqiang Zhang  Jinxian Zhong  Lianxiong Qiu 《Journal of Atmospheric Chemistry》1997,27(2):209-215

Rate constants for the reaction of hydroxyl radicals with dibromomethanehave been measured by discharge flow-resonance fluorescence technique(DF-RF) over the temperature range 288–368 K. The derived Arrheniusequation is k₁=(1.51 ± 0.37)× 10^-12 exp(-(720 ±60)/T) cm³ molec.^-1 s^-1.The tropospheric lifetime of dibromomethane has been estimated to be 0.29years. An ozone depletion potential (ODP) value of 0.10 for dibromomethanehas been obtained.  相似文献   

勘查金矿的现场X射线荧光法   总被引：5，自引：0，他引：5  

章晔  谢庭周  周四春  葛良全 《铀矿地质》1988,(1)

本文介绍了用X射线荧光法在野外勘查金矿的地质和地球化学的理论依据和物理基础,描述了X射线荧光分析仪和野外工作方法。最后,文章给出了用该法在野外找金的两个实例。  相似文献   

辉石相变的矿物物理特征及滑石瓷老化机理的探讨     

徐培苍  张晓云  李恩林 《矿物学报》1988,(2)

本文采用X射线衍射物相定量分析,透射电子显微镜及X射线电子能谱分析研究了原顽辉石→斜顽辉石的相变特征,提出了滑石瓷老化的实质是当原顽辉石Pbcn相向斜顽辉石P2_1/c相转变时,由于体积缩小和钡玻璃相拉应力的减少,导致滑石瓷表面产生微裂缝,从而加剧老化的过程。  相似文献   

累托石X射线衍射定量方法     

张荣英  吴方启 《矿物学报》1988,(3)

粘土矿物X射线衍射定量分析中常遇到的结晶度差异大,择优取向不易消除等困难,目前尚无完善的解决办法。笔者经过反复试验发现:被测物相的百分含量、衍射强度,结晶度及择优取向(定向度)之间存在着一定的函数关系,可以用图表或代数式来表达。用其来修正定量分析结果,消除因结晶度和定向度不一所产生的衍射强度误差,有效地提高了分析精度和可靠性。  相似文献   

Biogeochemical aromatic markers in the sediments from mahakam delta (Indonesia)     

P. Garrigues  A. Saptorahardjo  C. Gonzalez  P. Wehrung  P. Albrecht  A. Saliot  M. Ewald 《Organic Geochemistry》1986,10(4-6)

Analysis of the tri-, tetraand pentaaromatic hydrocarbon fractions of several sediments (0–600 m) from the Mahakam Delta (Indonesia), indicate the predominance of polycyclic aromatic hydrocarbons (PAH) diagenetically related to triterpenoid natural precursors. High resolution Shpol'skii spectrofluorometry (HRS) proved to be a valuable analytical tool, in conjunction with high performance liquid chromatography (HPLC) and capillary gas chromatography coupled with mass spectrometry (CGC/MS), for the identification of individual components in Chromatographic fractions obtained after a high resolution reverse phase liquid chromatography.  相似文献   

Relation between source rock properties and wireline log parameters: An example from Lower Jurassic Posidonia Shale, NW-Germany   总被引：1，自引：0，他引：1  

U. Mann  D. Leythaeuser  P.J. Müller 《Organic Geochemistry》1986,10(4-6)

The relationships between source rock quality and wireline log parameters were established for the Lower Jurassic Posidonia Shale, the most prolific petroleum source rock of Central Europe. Wireline logs used are the gamma ray spectrometry, density, sonic and various resistivity logs. The organic geochemical parameters considered include the organic carbon content, hydrogen index, and the hydrocarbon potential expressed by pyrolysis yield. The case history presented is based on a continuous core through the entire Posidonia Shale interval from a location where this source rock is immature. Care was taken to detect and to avoid samples and log values influenced by bore hole roughness and fractures. Fair correlations were observed only between uranium content from gamma ray spectrometry log and organic carbon content. No correlation was recognized between uranium content and kerogen type as defined by hydrogen indices. For various reasons density, sonic, and resistivity logs did not provide useful data in this study.Three rock units with irregular, high and low uranium contents could be differentiated. Possible causes for this tripartition are different environments during deposition and postdepositional redistribution of uranium during early diagenesis and in association with fractures.  相似文献   

Geochemical studies on Kashmir loess profiles     

G. S. Lodha  K. J. S. Sawhney  H. Razdan  D. P. Agrawal  N. Juyal 《Journal of Earth System Science》1987,96(2):135-145

Major and trace element concentrations of a few representative loess profiles in Kashmir valley are studied using EDXRF spectroscopy. Principal component analysis for pattern recognition has been employed to study association between elemental concentration variations in various horizons. The present study reveals that elements related to clay illuviation (K, Rb, Fe, Ti, Mn) and plant activity (Cu, Zn) are generally higher in B horizon of the palaeosols whereas Ca and Sr have a high concentration in the loess layers. Such an elemental concentration variation provides us with an objective index for identification and confirmation of palaeosols. There is further a close association in the movement of (i) K, Rb, (ii) Fe, Ti, Mn, (iii) Cu, Zn and (iv) Ca, Sr. These clusters of elements are also present in modern soils, suggesting that the soil characteristics in palaeosols have been preserved. Concentration of iron and titanium is also observed to be higher in loess profiles on Pir Panjal mountain flank which is dominated by basic rocks, compared to profiles on Himalayan flank, suggesting that the loess in Kashmir might have been derived from the nearby rocks in a localized way.  相似文献   

黑钨矿类质同象系列的X射线衍射研究     

王玉明  丘第荣 《矿物学报》1989,9(3):245-252

本文是黑钨矿类质同象系列研究成果的一个组成部分。通过对不同成分的黑钨矿类质同象系列的粉晶X射线衍射研究,发现各衍射峰的2θ值或d值及晶胞参数均与其成分x[Fe/F(e+Mn)]呈良好的线性关系。文中给出的一系列相关方程都可以用于黑钨矿成分的测定。在应用中,△(2θ_(111)-2θ_(111))与x以及△(2θ_(110)-2θ_(011))与x的相关方程尤为理想,因为它们免除了实验中系统误差的影响。但前一个相关方程仅在x<0.60的情况下适用。  相似文献   

内蒙古太古宙变质岩系中石榴石的矿物学特征及其地质意义   总被引：2，自引：0，他引：2  

张荫芳 《岩石矿物学杂志》1989,8(1):78-88

本文对内蒙古南部太古宙集宁群变质岩系中6个石榴石样品进行了研究,讨论了晶体形态、物理性质、化学成分与岩石成分和波谱学之间的关系。研究表明,本区(含石墨)富铝片麻岩类岩石中,石榴石以富镁的铁铝榴石组份为主,而二辉石岩中的石榴石则以富钙的铁铝榴石组份为主。石榴石钙的含量受岩石成分所控制。从测得的晶胞参数来看,除个别者外,a_0值均随着Ca~(2 )的含量增加而增大。据穆斯堡尔谱分析,本区集宁群变质岩系中除个别样品受到了氧化或蚀变而有Fe~(3 )成分混入外,大部分石榴石可能都是在变质程度比较高的还原环境下形成的。  相似文献   

Pyrolysis-GC-MS and NMR studies of dissolved seawater humic substances and isolates of a marine diatom     

Andrew H. Gillam  Michael A. Wilson 《Organic Geochemistry》1985,8(1):15-25

¹³C- and ¹H-NMR spectra were obtained for humic substances isolated from a coastal marine environment and also for the intracellular and extracellular extracts of a marine diatom. Phaeodactylum tricornutum Bohlin. Highly branched alkyl chains constitute a large proportion of the structure of the marine humic material, whereas aromatic components are less important. Carbohydrate-type materials, possibly uronic acids, are also present in appreciable amounts. Furans (derived from carbohydrates). pyrroles and nitriles (derived from proteins, nucleic acids and/or tetrapyrroles) and phenols and methylphenols (non-lignin derived) are pyrolysis products derived from pyrolysis-gas chromatography-mass spectrometry of the extracts. The results indicate the similarities in chemical structure of P. tricornutum exudate and dissolved marine humic material.  相似文献