• 보존과학연구
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• 통권23호
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• pp.197-214
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• 2002

It is very important to determine the age of the Cultural Properties in archeology. In about 1950, W.F. Libby and a team of scientists at the University of Chicago developed the Radiocarbon Dating technique. Radiocarbon($^14$C) Dating is probably one of the most widely used and best known absolute dating methods. Radiocarbon ages are conventionally specified to the year 1950. This year is 0 BP year. BP is the initial of Before Present. The $^14$C within an organism is continually decaying into stable carbon isotopes. When $^14$C decays, it emits a $\beta$ - particle with an energy content of 156 KeV and becomes 14N. Only the $\beta$ - particle is detected by Liquid Scintillation Counting. $^14$C has a half life of 5730 years. It has been used to date samples as old as 50,000 years. Radiocarbon determinations can be obtained on organic material : wood, charcoal, shell, etc. The results of radiocarbon dating using Benzene Synthesizer and Liquid Scintillation Counter are KCP539 $4030\pm60$BP year, KCP540 $3980\pm60$BP year, KCP575 $4870\pm50$, KCP576 $100\pm50$BP year, KCP577 $130\pm50$BP yea and KCP578 $210\pm70$BP year.

• Ocean and Polar Research
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• 제44권1호
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• pp.99-111
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• 2022

Together with the development of measurement techniques, radiocarbon (¹⁴C) has been increasingly used as a key tool to investigate carbon cycling and associated biogeochemistry in the ocean. In this paper, the current status of radiocarbon studies in the East Sea (Japan Sea) is reviewed. Previously, spatiotemporal distribution and change of the water masses in the East Sea from 1979 to 1999 were investigated by using the ¹⁴C in the dissolved inorganic carbon (DIC). Researches on sinking particulate organic carbon (POC) revealed that POC in the deep ocean has more complex and heterogeneous origins than we expected. In particular, since 2011, Korean researchers have been collecting sinking particle samples for more than 10 years, so it is expected that ¹⁴C of POC will provide important information to understand carbon cycling in relation to climate change. Although the quantity of ¹⁴C data published in the East Sea is still limited, the importance and the future direction of using ¹⁴C to understand the biogeochemical mechanisms of carbon cycling and its role as a carbon reservoir in the East Sea are detailed herein.

• 대한화학회지
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• 제14권1호
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• pp.49-50
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• 1970

A wet oxidation method of oxalic acid standard used in radiocarbon dating is described, and error due to possible carbon isotope fractionation during the oxidation is estimated.

• 한국대기환경학회지
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• 제16권4호
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• pp.421-428
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• 2000

Accelerator Mass Spectrometry (AMS) is presented for the applications to the environmental research. Traditionally the radiocarbon (14C) measurements have been made for the purpose of dating the archaeological and geological samples. 14C measurements using AMS however have become the more useful methods for the study of environmental science such as antropogenic modification of atmosphere and the determination of mixing ratios of fossil and biomass products. Such 14C AMS measurements have been extended to the discovery of new chemical tracers for investigations of sources of excessive contributions of CO2, CO, CH4 and other carbon-bearing molecules in the atmosphere.

• 대한화학회지
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• 제15권6호
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• pp.370-377
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• 1971

The Carbon-14 content in surface air at Seoul, Korea, was measured from February 1970 to August 1971 and a Larix Leptolepis, Gordon tree (Ip-Gal Namu) grown at Kwang-Nung, Kyunggi-Do, Korea, having 37 growth rings, was assayde for $^{14}C$. From the results of the surface air study, it was calculated that during the above period the inventory of excess $^{14}C$ in the atmosphere decreased with a half-time of 4.6 years. The overall yearly decrease was also checked. The tree-ring study showed that the tree's atmosphere was affected by $^{14}C$ from nuclear tests after 1956. In one study, atmospheric $CO^2$ samples were collected bi-monthly by the absorption of $CO^2$ in alkaline hydroxide solution. In the other, 5 year annual growth rings were assayed for radiocarbon. For the radioactivity measurement, carbon atoms in samples were converted to carbon atoms of benzene. The resulting benzene was taken as primary solvent for liquid scintillation counting.

• Journal of Microbiology
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• 제35권1호
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• pp.47-52
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• 1997

To examine whether the xylene component of BTX (benzene, toluene, xylene) mixture is cometabolized and residues are produced in soil, $\^$14/C-labeled-0-xylene was added to sandy loam in combination with unlabeled benzene and toluene. After 4 weeks of incubation in a sealed system connected to an oxygen reservoir, 55.1% of the radiocarbon was converted to $\^$14/CO$\sub$2/, 3.0% was to 95.8% radiocarbon recovery. Biomass incorporation of o-xylene radiocarbon which was detected by fumigation/extraction was usually low (5.6%), but 32.1% radiocarbon became associated with soil humus. Most of the numus-bound radiocarbon was found in humin fraction. In addition to o-xylene, p-xylene and toluene also showed similar results. The evidence shows that some of their reactive methylcatechol biodegradation intermediates attach to the humic metrix in soil in preference to mineralization and biomass incorporation.

• Nuclear Engineering and Technology
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• 제56권8호
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• pp.2906-2915
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• 2024

Radiocarbon (¹⁴C), with a radioactive half-life of approximately 5730 years, poses a long-term environmental contamination risk when released into the atmosphere. The quantification analysis of its release estimates plant-specific generation rates based on factors such as plant power, core neutron flux distribution, and the volume of water exposed to this flux. Utilizing the improved estimation method, the ¹⁴C production rate for several Korean Pressurized Water Reactors (PWRs) was calculated. Also, improvements in measurement methods through sampling have also been made. These enhancements include the verification of the absorption method versus the mixing method. The results of this study indicate that plant-specific ¹⁴C production rates range from 0.213 to 0.317 TBq/yr, which are comparable to the global range observed in PWRs. Furthermore, the study evaluated a quenching correction curve for a liquid scintillation counter using two quenching correction methods: the external standard method and the internal standard method. The accuracy of these methods with 72 samples was validated with an average relative error within ±2.5%. The relative error of the mixing method, when compared to the direct absorption method, was found to be within ±20%. This finding underscores the validity of the improved measurement technique.

• Ocean and Polar Research
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• 제36권2호
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• pp.111-119
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• 2014

이 연구에서는 동해의 해수 중 방사성탄소의 분지별 비교 및 시간에 따른 변화를 이해하고자 하였다. 1999년 동해의 일본분지, 울릉분지, 야마토분지 3개 분지에서 총 5개의 정점에서 채취한 시료로부터 방사성탄소를 분석하였다. 동해의 방사성탄소는 일반적인 대양에서의 분포와 유사하게 표층에서 2000 m 수심까지 가파르게 감소하는 양상을 보이며, 2000 m 보다 깊은 수심에서는 일정한 값을 보였다. 분지별로 방사성탄소의 수직분포를 비교해 보면, 3개의 분지의 표층(<200 m)에서 방사성탄소 값은 63~85‰ 이내로 유사하였으나 200~2000 m의 중층수에서는 분지별로 최대 60‰까지 차이가 나타났다. 중층수의 방사성탄소는 일본분지, 울릉분지, 야마토분지 순으로 높은 값이 나타나는데, 이는 중층수 순환의 형태와 그 분포가 일치한다. 2000 m 보다 깊은 수심의 저층수에서는 방사성탄소가 분지별로 뚜렷한 차이 없이 모든 분지에서 -80~-60‰ 내의 값을 보인다. 동해 표층수에서는 시간에 따라 매년 약 2‰씩 ${\Delta}^{14}C$ 값이 감소하였다. 반면, 동해 심층에서의 방사성탄소는 세개의 분지 모두 시간에 따라 증가하고 있다. 동해 중앙수의 방사성탄소는 매년 약 3.3‰ 증가하고 있는데, 이는 심층수나 저층수보다 시간에 따라 빠르게 증가한다. 심층수와 저층수에서는 방사성탄소가 1990년대 중반까지 증가하다가 1995년 이후로는 거의 증가하지 않고 일정한 값을 보인다. 심층수와 저층수에서의 ${\Delta}^{14}C$ 값의 시간에 따른 변화는 동해의 심층수 형성의 시간적 변화와 연관지어 해석되어야 할 것이다. 향후 동해 해수순환의 변화를 이해하기 위하여 방사성탄소 연구가 지속되어야 할 것이다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제6권2호
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• pp.15-22
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• 2001

방사성동위원소인 $^{14}C$(반감기 5,730년)는 삼중수소와 함께 수리지질학에서 지하수의 체류시간을 평가할 수 있는 유용한 도구로 활용된다. 그러나 국내에서는 $^{14}C$ 분석을 위한 전처리 기술의 부재로 인하여 오랜 체류시간을 지닌 국내 지하수 및 수문체계에 대한 평가가 이루어지지 뜻하였다. 그동안 $^{14}C$은 주로 벤젠합성법을 이용하여 분석되었지만, 실험과정이 복잡하고 많은 시간이 요구되어 지하수연구에 제한적으로 이용되어 왔다. 최근에 이산화탄소의 직접흡수법을 이용한 $^{14}C$분석법이 개발되었으며, 국내 지하수연구에도 적용될 수 있는 $^{14}C$ 분석법을 확립하였다. 분석과정 및 결과의 신뢰성을 위하여 국제인정기관(CSIRO, 호주)과의 교차분석을 수행하였다. 앞으로 $^{14}C$ 분석은 국내 심부지하수의 유동 연구에 매우 유용하게 활용될 수 있을 것으로 기대된다.

• 한국해양학회지:바다
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• 제4권3호
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• pp.180-187
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• 1999

벤젠-액체 섬광계수법에 의한 $^{14}C$연대측정을 하동 목도리 패총에서 산출된 굴패각을 대상으로 행하였다. 본 논문에서는 이러한 측정방법을 기술하고 그 결과를 비교 검토하였다. 시료는 전처리, 탄산스트론튬, 스트론튬카바이트, 아세틸렌 및 벤젠합성의 제조과정을 거쳤고, 계측은 Wallac 1415 Liquid Scintillation Counter를 사용하였다. 연대측정 결과 본 대학에서는 $4905{\pm}112$ yr BP, 시마네 대학은 $4912{\pm}123$ yr BP로서 거의 통일한 연대치로 나타났다. 벤젠-액체섬광계수법에 의한 $^{14}C$연대측정은 간편히 사용할 수 있는 방법으로서 대학 및 연구소 등에서 보편적으로 사용할 수 있을 것으로 사료된다.