论文部分内容阅读
研究了1994年8－9月南海东北部表层海水中228Ra的分布特征。采用Mn－纤维富集海水中的Ra同位素，通过其子体228Ac的β计数法来测量228Ra。表层海水中228Ra的放射性比活度从2．48Bq·m－3变化到4.47Bq·m－3，平均值为3.24Bq·m－3。228Ra的水平分布表现为调查海区东北部比活度较高，这与该航次的226Ra的分布特征相一致。根据各断面的228Ra放射性比活度与离岸距离之间的负相关关系，计算了它们所对应的水平涡动扩散系数，并讨论海域的地貌特征对228Ra比活度分布的影响。这些研究结果对表层水体的混合、交换，尤其是可溶性污染物的迁移、扩散以及海域的自净作用的研究都具有实际意义。
The distribution of 228Ra in surface seawater from northeastern South China Sea from August to September in 1994 was studied. The Ra isotopes in the seawater are enriched with Mn-fibers and 228Ra is measured by the beta count of its daughter 228Ac. The specific activity of 228Ra in surface seawater changed from 2.48Bq · m-3 to 4.47Bq · m-3 with an average of 3.24Bq · m-3.228Ra. The horizontal distribution showed that the specific activity High, which is consistent with the distribution of 226Ra of the voyage. Based on the negative correlation between the specific activity of 228Ra and the offshore distance of each section, the corresponding horizontal eddy diffusivity was calculated and the influence of the sea surface topography on the specific activity distribution of 228Ra was discussed. The results of these studies have practical significance for the mixing and exchange of surface water bodies, especially the migration and diffusion of soluble pollutants and the self-purification of sea areas.