浙北富硒土壤地球化学特征与生物学效应

通过对杭嘉湖平原富硒区研究,发现区内富硒土壤主要分布在环湖平原区,土壤具有特殊的地球化学性质,表现为土壤酸性,土壤硒全量0.3～0.5 mg/kg,有机质含量高、重金属含量低,土壤质地较黏重,土壤硒与有机质关系密切,而与土壤pH相关性不明显等特点。在土壤有机质丰富和氧化条件下,农产品中硒含量较高,重金属低于限量标准,具有较好的开发远景。     

Potential of X-Ray Diffractometry in Structure Identification of Holmium Polysulfides

A series of experiments have been carried out to synthesize holmium polysulfides at temperatures from 600 to 840°C and sulfur vapor pressures of (2.1, 6.5, 16.7)á10⁵ Pa. Polysulfide crystals sized up to 2 mm and micron-sized powders were investigated thereafter by powder diffractometry. Powder diffraction patterns were calculated based on our previous X-ray structural data. Characteristic reflections have been revealed for the individual monoclinic and tetragonal phases, and X-ray phase analysis (XRPA) has been performed for all batches of the synthesis. The monoclinic phase is shown to prevail irrespective of the synthetic conditions. The tetragonal phase was found in amounts of up to 10 wt.%.     

广西合山石村矿超高有机硫煤饱和烃特征分析

以合山石村矿超高有机硫煤为研究对象,利用带能谱的扫描电镜(SEM-EDX)及气相色谱(GC)和色谱-质谱联用(GC-MS)分析技术,综合分析探讨了研究区样品中有机质来源、沉积环境及物源输入。结果表明,研究区样品镜质体反射率均值1.76%,全硫含量均值6.01%,其中有机硫含量占比达94.3%,为高成熟度的超高有机硫煤。饱和烃色谱图中未分辨的复杂混合物(UCM)鼓包明显,前峰及双峰型均有分布,前峰型主峰碳为C₁₆、C₁₈、C₂₁,双峰型主峰碳为C₁₈、C₂₇,化合物降姥鲛烷、脱氢松香烷、咔达烯均有发现,规则甾烷C₂₇、C₂₈、C₂₉均呈"V"型分布,说明沉积母质受藻类等低等水生生物与高等植物双重输入的影响。姥植比参数、C_31-35藿烷呈阶梯式递减的分布特征表明在海相碳酸盐台地成煤带中存在一定的氧化条件。扫描电镜中拍摄到的铁含氧硫酸盐、细胞充填环状黄铁矿说明在沉积质晚期成岩阶段受到一定程度热液作...     

溴的生物必需性(二)

根据微量元素必需性的经典定义,从溴的生态地球化学、溴的生物学功能及溴的人体健康效应方面论述了溴是生命必需微量元素的16项理由.分3期刊出.本期发表第二部分.     

渭北晚古生代煤层中镧系元素的地球化学效应及理论意义

运用数理统计的相关性分析方法研究了渭北晚古生代煤中镧系元素的地球化学行为.结果表明,在通常情况下,任一地质体中的镧系元素经球粒陨石标准化后的数值,会随着其+3价离子半径的变化而呈有规律的线性变化,不同地质体之间镧系元素的比值变化,也受控于其+3价离子半径,此为作者以前发现的“镧系元素地球化学效应”的另一种表现形式.据此...     

ORGANIC GEOCHEMISTRY OF ARTIFICIALLY HEATED SPHAGNUM COAL CONSIDERED AS POSSIBLE SOURCE ROCK FOR OIL AND GAS

A preliminary study of simulated thermal maturity has been conducted to evaluate the oil, gas and hydrocarbon generation potential of sphagnum coal in the Jinsuo brown coal basin, Yunnan Province and to understand the characteristics of the element composition and biomarkers in the course of thermal alteration. The experimental result was compared with that of xylitic coal, a kind of lithotype of soft brown coal. It is considered that sphagnum coal possesses the potential of forming economic accumulation of oil and gas. Its highest proportion of oil and hydrocarbon generation is 510 mg/g Corg. and 232.1 mg/g Corg. respectively. At an R_(ran)~° value of 2.51%, the ratio of gas generation from sphagnum coal attains to 620.5 ml/g Corg. In view of sphagnum coal being different from the conventional soft brown coal in various respects such as coal forming raw materials and enviroments as well as physico-chemical properties, it is Suggested as a special kind of source rock for coal-generated oil and gas.     

马家塔矿煤层中有害痕量元素的质量分数特性

应用仪器中子活化（INAA）、电感耦合等离子体原子发射光谱（ICP AES）和原子吸收光谱（AAS）对神华集团马家塔露天矿2-2#煤层中Hg、As、Se、Pb、Be、Cr、Cd、Ni、Th、U、Mn、Mo、Co、Sb和Br共15种有害痕量元素的质量分数进行测定。结果表明,绝大部分痕量元素的质量分数都明显低于中国煤中元素质量分数的平均值,只有Hg和Mn的质量分数偏高,其中Hg的质量分数异常高;通过分析痕量元素在煤层垂向剖面上的质量分数变化特性,揭示出痕量元素在煤层中分布的非均一性,分析了影响痕量元素分布与富集的因素;通过痕量元素之间以及与黄铁矿硫、Fe、Al、Ca、P的聚类分析,研究了痕量元素之间以及与煤中不同矿物组分之间的亲和特性。     

Syntheses of per-N labeled etioporphyrins I-IV and a related tetrahydrobenzoporphyrin for applications in organic geochemistry and vibrational spectroscopy

Nitrogen-15 labeled pyrroles have been prepared from commercially available ¹⁵N glycine or sodium nitrite using the Barton-Zard, Knorr, and Kleinspehn approaches. These pyrroles were used as intermediates in the synthesis of per-¹⁵N labeled porphyrins needed for the analysis and assignment of vibrational spectra for sedimentary porphyrins. Etioporphyrin-I was prepared via pyrromethene intermediates, while etioporphyrins II-V and a related tetrahydrobenzoporphyrin were synthesized via stepwise routes involving the copper(II) mediated cyclization of a,c-biladienes as the key step. Detailed analyses of both the proton and carbon-13 NMR spectra provide nitrogen-15 coupling constants for these important structures.