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中子活化分析法研究宇宙尘 总被引:1,自引:0,他引:1
一、绪言中子活化分析法是一种灵敏度高、取样量少、且在同一试样中可以同时测定多种微量元素的分析方法。我们所研究的尘埃物质的粒径从几微米到几百微米,重量由几微克到几百微克。这些尘粒大部分是地质学家从深海钻井中取出并仔细挑选出来的,获得试样很不容易。然而要辨认试样是否为宇宙尘则更困难,用一般的化学、物理方法很难给出结论。宇宙尘的研究能为太阳系的形成与演化、行星的起源与发展、反演地壳物质的演化过程和探讨地壳物质的演化提供资料,因此用中子活化法研究宇宙尘的研究工作日趋活跃。从中子活化分析给出的多种微量元素含量的结果,特别是贵金属元素铱、锇、钌和铼,亲铁元素镍、钴等 相似文献
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CHEMICAL SPECIES OF IRIDIUM AND OTHER TRACE ELEMENTS AT K-T BOUNDARY CLAY LAYER, STEVNS KLINT, DENMARK, AND ITS IMPLICATION 总被引:2,自引:0,他引:2
The chemical species of anomalous Ir in the Fish Clay K-T boundary at Stevns Klint, Denmark, was studied by using a newly-developed chemical stepwise dissolution procedure and neutron activation analysis. The experimental results indicate that the anomalous Ir mostly exists in the acid-insoluble residue phase. The Ir pattern of the K-T boundary resembles that of the Ningqiang carbonaceous chondrite, while remarkably different from those of the ultrabasic rock and volcanic lava. Thus, we deduce that the Ir anomaly at K-T boundary is mainly extraterrestrial, instead of volcanogenic or geochemical enrichment origin. The patterns of other trace elements in various phases also confirm the above conclusion. 相似文献
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Two episodes of paleoredox fluctuation variation are indicated in some localities in thelate Cretaceous--early Tertiary ocean of western Tarim recorded by REE distribution patterns,Ce anomalies, and Th/U ratios from systematic studies on the chemical composition, withspecial reference to REE and 20 trace elements, based on 11 marine shell fossils occurringin the Upper Cretaceous--Lower Tertiary strata of the western Tarim Basin, Xinjiang. Thefactors Controlling the redox fluctuation may be probably caused by shifting places ofsurface runoff put into the sea as a result of transgression and regression. 相似文献
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1 引 言由于有机卤族化合物污染的普遍性和突出的“三致”作用 (致癌、致突变、致畸形 ) ,有机卤族化合物的环境行为一直是环境化学的研究热点 ,也是世界各国重点控制的污染物。有机卤族化合物的分析测定一直由色谱完成 ,但由于该类化合物有成千上万种 ,色谱分析不可能对样品中的所有有机卤族化合物进行定性和定量分析。有研究表明 :色谱分析结果只占实际污染水平的 1%~ 2 6% ,并不能准确反映有机卤族化合物的总体污染水平。中子活化分析 (NAA)是目前唯一一种能同时定量测定有机Cl、Br和I的方法。本工作用中子活化分析测定了牛… 相似文献