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14C/12C Variations of Samples Exposed in Air According to Carbon Structure and Air Temperature

Published online by Cambridge University Press:  09 February 2016

J H Park*
Affiliation:
Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong, Daejeon 305-350, Korea
W Hong
Affiliation:
Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong, Daejeon 305-350, Korea
G Park
Affiliation:
Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong, Daejeon 305-350, Korea
K S Sung
Affiliation:
Korea Institute of Geoscience and Mineral Resources, 124 Gwahang-no, Yuseong, Daejeon 305-350, Korea
*
1Corresponding author. Email: junghun@kigam.re.kr.

Abstract

Various carbon structures, including carbon nanofilament (CNF), single-wall carbon nanotube (SWCNT), multi-wall carbon nanotube (MWCNT), and pyrolytic graphite sheet (PGS), were exposed in air to determine how they vary according to carbon structure and air temperature. CNF is the carbon structure used in accelerator mass spectrometry (AMS) radiocarbon dating (Santos et al. 2007). When CNF and MWCNT were exposed in cold air (3 or −18 °C) for longer than 6 hr, their 14C/12C ratio increased (>5 × 10–14). When heated in an oven (200 or 250 °C) for longer than 12 hr, their 14C/12C ratio decreased. However, when SWCNT and PGS were exposed in air cooled to 3 °C for 12 hr, their 14C/12C ratio did not increase. This phenomenon is very curious, and is useful for the development of a storage method for carbon samples made by reduction reactions of CO2.

Type
Articles
Copyright
Copyright © 2013 by the Arizona Board of Regents on behalf of the University of Arizona 

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References

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