• Title/Summary/Keyword: Radiocarbon

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Decadal Observation and Studies in the Amundsen Sea, Antarctica: Insights from Radiocarbon Values (10여년간의 서남극 아문젠해 관측과 연구: 방사성탄소동위원소 값을 중심으로)

  • Kim, Minkyoung
    • Ocean and Polar Research
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    • v.44 no.1
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    • pp.83-97
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    • 2022
  • The Amundsen Sea in West Antarctica is one of the most affected regions by climate change, but it is one of the least studied realms due to difficulties in access. Korea Polar Research Institute (KOPRI) launched a research project in the Amundsen Sea in 2010 using the icebreaker research vessel (IBRV) Araon and has been conducting various research initiatives. In this paper, previous researches derived from the Amundsen Sea Embayment by Korean researchers are introduced. Through previous studies, researchers have been able to interpret the environmental and biogeochemical changes according to the inflow Circumpolar Deep Water (CDW) and provide information for climate models. In particular, researches using radiocarbon isotopes (14C) were introduced to understand the physical and biogeochemical mechanisms of the carbon cycle in the Amundsen Sea. Opportunely, with the construction of a second icebreaker research vessel, the direction for systematic and long-term polar data acquisition can be presented.

Absolute Age Determination of Gangmun-dong Sites Gangneung, Gangwon-Do-Radiocarbon and Thermoluminescence Dating - (강릉 강문동 유적의 절대연대측정 - 방사성탄소연대 및 열발광연대 -)

  • Kang, Hyung-Tae;Chung, Kwang-Yong
    • Journal of Conservation Science
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    • v.18 s.18
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    • pp.97-104
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    • 2006
  • Absolute ages for three pieces of organic materials such as wood and shell were determined with radio-carbon concentrations and two potsherds with thermoluminescence measurements. Radiocarbon contents of each sample were compared with those of modern standard oxalate(NBS SRM4990C) and calculated radiocarbon ages of them. Quartz grains with diameter of $90\sim150{\mu}m$ were extracted from potsherds and used for measuring the archaeodose. Annual dose were calculated with measuring the alpha count rates and water contents and analysing $K_2O$ concentration of both potsherds and soils. Radiocarbon ages of organic materials were in the ranges of $4\sim2C$ BC and Quartz grain techniques for thermoluminescence dating showed 170 BC ud 210 BC respectively. It was found that the results of radiocarbon dating and TL dating were accorded with each other. But the deviations of TL dating have shown 13% and 20% respectively. It need to reduce the deviations.

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Accelerator Mass Spectrometry in Environmental Research (가속기 질량 분광분석법을 이용한 환경 연구)

  • 문창범
    • Journal of Korean Society for Atmospheric Environment
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    • v.16 no.4
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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.

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Study on the Radiocarbon Dating with Liquid Scintillation Counting (액체섬광계수법을 이용한 방사성탄소 연대측정법 연구)

  • Kim, Nak Bae;Woo, Hyung Joo;Hong, Wan;Cho, Soo Young
    • Analytical Science and Technology
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    • v.5 no.4
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    • pp.381-387
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    • 1992
  • Optimum counting condition of a low level liquid scintillation counter for radiocarbon dating has been determined to minimize the contribution of tritium activity and get the highest FOM by the variation of scintillation solutions, scintillation solution to benzene ratio, and ${\beta}$-ray spectrum counting ranges. Under the condition, background count rate has been reduced to $2.26{\pm}0.03cpm$, and the maximum measurable age reached to about 40,000 years. And the practicality of counting system has been verified by the analysis of shell and peat samples.

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Stable Isotope Chemistry of Bone Collagen and Carbonate Assessed by Bone Density Fractionation

  • Shin, Ji-Young
    • Bulletin of the Korean Chemical Society
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    • v.32 no.10
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    • pp.3618-3623
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    • 2011
  • This paper presents a stable isotope chemistry of bone collagen and carbonate. Bone carbonate has the potential to provide additional isotopic information. However, it remains controversial as to whether archaeological bone carbonate retains its original biogenic signature. I used a novel application of bone density fractionation and checked the integrity of ${\delta}^{13}C_{apa}$ values using radiocarbon dating. Diagenesis in archaeological bone carbonate still remains to be resolved in extracting biogenic information. The combined use of bone density fractionation and differential dissolution method shows a large shift in the ${\delta}^{13}C_{apa}$ values. Although ${\delta}^{13}C_{apa}$ values are improved in lighter density fractions, a large percentage of contamination in bone carbonate was reported via $^{14}C$ dating compared to that noted with bone collagen.

Radiocarbon Dating Practices by Benzene Liquid Scintillation Method (벤젠-액체 섬광계수법에 의한 $^{14}C$ 연대측정)

  • Lee, Yeon-Gyu;Choi, Jeong-Min;Kim, Chang-Gyu
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.4 no.3
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    • pp.180-187
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    • 1999
  • Radiocarbon dating method using benzene liquid scintillation was performed on the oyster shell fragments which producted from the shell mounts at Hadong Mogdori in Kyeongsangnamdo. This paper described to the age dating method and compared to the result. The carbon in sample is synthesized to a benzene through the sample preparation, $SrCO_3$, $SrC_2$, $C_2H_2$ and $C_6H_6$ synthesizing process. Age dating is calculated by Wallac 1415 Liquid Scintillation Counter. The result of age dating is estimated to be $4905{\pm}112$ yr BP in Yosu Univ. which is a good agreement with the result in Shimane Univ. ($4912{\pm}123$ yr BP). Radiocarbon dating method using benzene liquid scintillation is a simple and economical in operation and establishment, it has a potential instrumentation in the university and research institute.

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A Fundamental Study of the Silla Shield through the Analysis of the Shape, Dating, and Species Identification of Wooden Shields Excavated from the Ruins of Wolseong Moat in Gyeongju (경주 월성 해자 유적 출토 목제방패의 형태, 연대 및 수종분석을 통한 신라 방패의 기초적 연구)

  • NAM, Tae-Gwang;KIM, Hun-Suk
    • Journal of the Korean Wood Science and Technology
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    • v.49 no.2
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    • pp.154-168
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    • 2021
  • Various types of wooden relics are being unearthed following the full-scale excavation in Wolseong palace site, Gyeongju in Korea. In particular, a large number of relics were found in the moat surrounding the Wolseong Fortress. This study attempted to secure basic data on the shields of the Silla era through species identification, radiocarbon dating, and shape analysis of the two wooden shields excavated from the Wolseong moat. As a result of the radiocarbon dating, it was confirmed that the shields were made of wood procured in the period between the mid-4th century and the early 5th century. The species identification confirmed that the body of the relic was made with Pinus soft pine group and the handle with Zelkova serrata. It was also confirmed that the excavated wooden shield was made by first marking a thin line on a flat grain board, then marking double concentric circles and perforating small holes. The distance between the division lines is constant at about 6cm, and spaces between them are colored in red and black. The shape analysis estimated that two artifacts were more than 50cm and 36cm in width, respectively.

Sediment Trap Studies to Understand the Oceanic Carbon Cycling: Significance of Resuspended Sediments (퇴적물 트랩을 이용한 해양 탄소 순환 연구 동향: 재부유 퇴적물의 중요성)

  • KIM, MINKYOUNG
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.26 no.2
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    • pp.145-166
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    • 2021
  • For several decades, sediment traps have served as one of the key tools for constraining the biological carbon pump (BCP), a process that vertically exports particulate organic carbon (POC) and associated biogenic materials from marine primary production in surface waters to the deep ocean interior. In this paper, I introduced the general methods, the current status of global sediment trap studies, and importance of it to understand the deep ocean carbon cycling. Recent studies suggest that sinking POC in the deep ocean are more complex and spatio-temporally heterogeneous than we considered. Especially researches those studied resuspended and laterally transported particles are presented. Researches that used organic (radiocarbon; 14C) and inorganic (Al) tracers to understand the oceanic POC cycling and the significance of resuspended particles are reviewed, and the importance of radiocarbon study by using MICADAS (Mini radioCarbon Dating Systems) is emphasized.