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由碳14测年技术想到的:人体是一个强辐射源吗?
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作者 林喆阳 《知识窗(教师版)》 2017年第18期92-93,共2页
由碳14测年技术想到,人体含有的碳14辐射有多强?为此,本文探究了生物体中碳14的来源,碳14测年技术的原理和方法。估计了60公斤人体中所含碳14的放射性活度约为2500个/秒,相应的辐射剂量为0.033毫西弗/年,这远低于我国辐射安全标准规定... 由碳14测年技术想到,人体含有的碳14辐射有多强?为此,本文探究了生物体中碳14的来源,碳14测年技术的原理和方法。估计了60公斤人体中所含碳14的放射性活度约为2500个/秒,相应的辐射剂量为0.033毫西弗/年,这远低于我国辐射安全标准规定的1毫西弗/年。因此,人体中所含碳14的放射性对健康没有影响。 展开更多
关键词 碳14测年放射性 同位素衰变规律 放射性活度 辐射剂量
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Radiocarbon Dating of Vertisols in China 被引量:1
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作者 LIU LIANGWU(Institute of Soil Science,Academia Sinica,P.O.Box 821,Nanjing 210008 China) 《Pedosphere》 SCIE CAS CSCD 1996年第2期147-153,共7页
Vertisols,which are mainly developed on fiuvial and lacustrine deposits and basalt,are extensively distributed in China. 66 samples of them for radiocarbon dating were collected across 5 provinces and 1 autonomous reg... Vertisols,which are mainly developed on fiuvial and lacustrine deposits and basalt,are extensively distributed in China. 66 samples of them for radiocarbon dating were collected across 5 provinces and 1 autonomous region, ranging from warm-temperate to subtropical and tropical zones in China.The soil organic matter was dated via surfaCe horizon, black soil horizon and dark-colour horizon of the vertisols,whereas carbonate through calcareous concretions and dispersed carbonate in soil profile using radiocarbon method. The present article elucidates the dates of genetic horizons,and of surfaCe and buried vertisols as well. 14C dating indicates that the surface vertisols were formed during the end of the late Pleistocene,ca.15600 years ago.Correlation between depth of sampling and measured 14C age shows that age characteristics of the vertisols of China are close to those of West Germany,Italy,Turnisia,Australia and Argeentia. However, two buried vertisols developed on fluvial and lacustrine deposits were formed during different geological periods.The buried soils in warm-temperate zone were formed in the mid Holocene, while those in subtropics were buried at 12930 years B.P.,and formed in the end of the late Pleistocene. 展开更多
关键词 buried vertisois soil ̄(14)C age surface vertisols
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