单词	carbon 14
释义	carbon 14 noun : a heavy radioactive isotope of carbon of mass number 14 used especially in tracer studies and in dating old materials (such as archaeological and geologic specimens) Example Sentences Recent Examples on the Web The researchers followed up with tree rings and saw a corresponding spike of carbon 14. Jonathan O'callaghan, Scientific American, 13 Sep. 2021 Studying carbon 14 data in tree rings from this era, the team found another spike. Jonathan O'callaghan, Scientific American, 13 Sep. 2021 Poring through them for events such as carbon 14 spikes is time-consuming, however. Jonathan O'callaghan, Scientific American, 13 Sep. 2021 While alive, animals and plants tend to contain the same levels of carbon 14 as their environment. Scott Hershberger, Scientific American, 4 Aug. 2020 All living things absorb carbon 14, a radioactive carbon isotope that decays at a regular rate over time. Megan I. Gannon, Scientific American, 1 Sep. 2020 Radiocarbon dating is based on measurement of the radioactive isotope, carbon 14, and radioactive decay is a random process at the atomic level, so any 14C measurement depends on the statistical behavior of all the 14C atoms present. Kiona N. Smith, Ars Technica, 5 Mar. 2020 See More Word History First Known Use 1946, in the meaning defined above Medical Definition carbon 14 noun -(ˈ)fōr(t)-ˈtēn, -(ˈ)fȯr(t)-  : a heavy radioactive isotope of carbon of mass number 14 used especially in tracer studies and in dating archaeological and geological materials
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