@article{oai:nagoya.repo.nii.ac.jp:00011862,
 author = {中村, 俊夫 and NAKAMURA, Toshio and 渡邊, 隆広 and WATANABE, Takahiro and 松中, 哲也 and MATSUNAKA, Tetsuya and 西村, 弥亜 and NISHIMURA, Mitsugu and 朱, 立平 and ZHU, Liping and 太田, 友子 and OHTA, Tomoko and 南, 雅代 and MINAMI, Masayo},
 journal = {名古屋大学加速器質量分析計業績報告書},
 month = {Mar},
 note = {To answer a question whether ^<14>C concentration is higher for plants growing at high altitude locations than those growing at the sea level, we recently have collected plants samples from four sites at different altitudes: (1) plants from Lake Pumayum area at the altitude of 5030m; (2) plant samples from the suburbs of Lhasa city at the altitude of 4000m; (3) needle leaves from pine tree at 2600m-high location of Mt. Fuji; and (4) needle leaves from pine trees growing in the Higashiyama Campus of Nagoya University. The plant samples were rinsed with distilled water, treated chemically by an acid- alkali-acid treatment, and finally dried in an electric oven. A part of the samples were combusted to produce CO_2 and the produced CO_2 was changed to graphite for ^<14>C measurements with an AMS ^<14>C system at Nagoya University. The measured ^<14>C concentration was given in a ratio of sample ^<14>C/^<12>C to that of standard. For both sample and standard, isotopic fractionation was corrected. In addition, the decrease of ^<14>C concentration by radioactive decay for a standard from AD1950 to the year of sample collection was also corrected. ^<14>C concentrations were highest for the plant samples from Lake Pumayum showing a value of 1.081±0.016 in average, followed by the values of 1.055±0.005 for plants near Lhasa city, the values of 1.051±0,002 for plants from Mt. Fuji, and finally 1.017±0.003 for pine needles from Nagoya University. This clear altitude dependence may be explained preferably by Suess effect that is a dilution effect of modern ^<14>C concentration with dead carbon, containing no ^<14>C, produced by combustion of fossil fuel. The estimated altitude dependence of ^<14>C atom production is not strong and the resulting altitude dependence of ^<14>C concentration of CO_2 can fade out quickly by the strong air-mass mixing in the troposphere., 第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告<第2部> Proceedings of the 20th symposiumon on Chronological Studies at the Nagoya University Center for Chronological Research in 2007 日時:平成20 (2008)年1月10日(木)～11日(金) 会場:名古屋大学野依記念学術交流館 Date:January10th-11th, 2008 Venue:Nagoya Uhiversity Noyori Conference Hall},
 pages = {110--116},
 title = {標高5000mのチベット高原に生育する植物は低地の植物より ^<14>C濃度が高いのか?(第20回名古屋大学年代測定総合研究センターシンポジウム平成19(2007)年度報告)},
 volume = {19},
 year = {2008}
}