nuclear energy-measurement of radioactivity in the environment-water-part 3 : beta emitters activity measurement by liquid scintillation-particular case of simultaneous presence of tritium and carbon 14 核能.环境放射性测量.水.第3部分:通过液体闪烁测量辐射物活性.同时出现氚和c14的特殊情况
radioactive matter is incorporated into plants, which are then eaten by animals with the result that most foodstuffs have a measurable amount of radioactivity . additional radioactivity in food comes from the naturally occurring isotope carbon 14 . some cosmic radiation also reaches sea level 植物亦混有辐射物质,而动物吃掉植物,以致绝大部份食物也含有一定辐射食物辐射也来自天然的同位素碳十四,此外,宇宙辐射亦可穿越大气层照射到海面。
the reassessment is based on advances in eliminating modern carbon contamination from ancient bone fragments and recalibration of fluctuations in the pattern of the earth's original carbon 14 content . populations of anatomically and behaviourally modern humans first appeared in the near eastern region some 45, 000 years ago and slowly expanded into southeastern europe 另外,传统理论还认为,现代人祖先最初于大约4.5万年前在欧洲东部地区出现,随后在4.3万年至3.6万年以前逐渐向东南欧地区迁移。
carbon 14とは意味:放射性炭素{ほうしゃせい たんそ}◆炭素の放射性同位体。年代測定によく用いられる炭素14を意味する場合もある carbon 14 meaning: Noun: carbon 14 'kaa(r)bun for'teen A radioactive isotope of carbon - radiocarbon Type of: atomic number 6 , C , carbon Encyclopedia: Carbon 14 carbon 14 뜻:phrase, 탄소 14(탄소의 방사성 동위 원소, 기호 C14)