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Discussed in this paper are the regularities governing the prevalence of Keshan disease and its relationship te the local rock type, soil, vegetation, climate and landform, as well aa to the characteristic variations of stereo-environment- environmental gradient in Yunnan Province. Based upon the foregoing discussion, the gradations of environmental quality and the coefficients of environmental quality mirroring the general picture of physical environment there have been determined, and a model of environmental quality has been established with an attempt to detail the relationship between the factors of environmental geology and Keshan disease. 相似文献
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微量元素钼预防克山病的实验研究 总被引:2,自引:0,他引:2
The role of trace element Mo in the prevention of Keshan disease is a new subject in environmental geochemistry. Experimental observations have shown that the natnral incidence of Keshan disease has dropped obviously among inhabitants in the Keshan disease-affeeted areas as a result of six-year successive spreading of anomium molybdate in the crop fields because in doing so the level of molybdenum has been enhaneed in grain crops while the concentrations of nitrates and nitrites have been reduced remarkably in the environment. Experimental results demonstrate that molybdenum may play an effective role in the prevention of Keshan disease. 相似文献
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The pulsational characteristics of magmatic activity are discussed in terms of potyeyelcs, polyphases and polystagcs for Mesozoic granites from Ⅰ,Ⅱ, Ⅲ areas.Based on 141 rock analyses, 80 semiquantitative spectrographic analyses for the granites and 50 chemical analyses for beryllium, niobium and tantalum, the authors present pertinent diagrams and petrochemical-geoehemical parameters which bring out the periodic variations in the bulk chemical composition of the rocks as wen as the periodicity of rare metal mineralization during the differentiation and evolution of Mesozoic granitic magmas. It is noted that the mineralization of lithium, beryllium, niobium and tantalum took place principally at later stages of each magmatic cycle. A camparison of the petrochemical-geochemical characteristics between granites east and west of the L-R Fault has led to the recognition of two different granite areas and two geochemical provinces for beryllium. 相似文献
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