• Title/Summary/Keyword: OSL

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Morphological Correlation and Chronology of Lower Terrace Formations of Southeastern Coast of Korea (한국 남동해안 저위단구 퇴적층의 지형대비 및 형성시기 고찰)

  • Choi, Weon-Hack;Kim, Ju-Yong
    • Proceedings of the Korean Quaternary Association Conference
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    • 2005.10a
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    • pp.48-54
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    • 2005
  • Terrace morphology is so conspicuous in the south eastern coastal areas. Coastal terraces can be divided into 5 main surfaces, including beach and coastal alluvial plain(AP, $4{\sim}5m$), Low Terrace(LT, 8 $^{\sim}$ 25m), Middle Terrace(MT, 36 $^{\sim}$ 55m), High Terrace(HT, 63 $^{\sim}$ 86m) and upper High Terrace(uHT, above 90m). Among them Lower Terrace Formation is distributed between 8m and 20m in altitude. Both Tephra deposited of LT2 formation and OSL datings of sand layers in LT 2 and LT 3 Formations support the age of the LT 2 formation is MIS 5d or 5e, most probably 5e. The age of LT 3 is interpreted MIS 5a, based on tephra production in organic mud layers and OSL dating of sand deposits just above the beach pebbles of the LT 3. Particularly the transgression, possibly equivalent to the well-known Monastirrian episode in the Mediterranean Sea.

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Age Constraints on Human Footmarks in Hamori Formation, Jeiu Island, Korea (제주도 하모리층에 발달하는 사람 발자국의 형성시기)

  • Cho Deung-Lyong;Park Ki-Hwa;Jin Jae-Hwa;Hong Wan
    • The Journal of the Petrological Society of Korea
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    • v.14 no.3 s.41
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    • pp.149-156
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    • 2005
  • Ar-Ar, carbon AMS and OSL dating was carried out to clarify the age of the human footmarks on the Hamori Formation, Jeju Island, Korea. $^{40}Ar/^{39}Ar$ ages of trachybasalt from the Songaksan Tuff, which is underlain by the Hamori Formation, range between $10.6{\pm}19.9\;Ka$ and $11.7{\pm}26.3\;Ka$. Radiocarbon AMS ages of humin fractions extracted from sediment samples yielded the maximum limit age of the Hamori Formation as $15,161{\pm}70\;yr$ B.P. The OSL dating of the top and bottom layers of the Hamori Formation gave $6.8{\pm}0.3\;ka$ and $7.6{\pm}0.5\;ka$, respectively, suggesting that timing of the human footmarks formation can be constrained as between ca 6,800 yr B.P. and 7,600 yr B.P.

Electrically Controllable Asymmetric Split-Loop Terahertz Resonator with Outer Square Loop (전기적 제어 가능한 외곽 사각 고리 추가형 테라헤르츠 비대칭 분리고리공진기)

  • Park, Dae-Jun;Ryu, Han-Cheol
    • Korean Journal of Optics and Photonics
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    • v.28 no.2
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    • pp.59-67
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    • 2017
  • This paper proposes an asymmetric split-loop resonator with an outer square loop (ASLR-OSL), which can actively control terahertz wave transmission properties while maintaining a high-Q-factor of the asymmetric split-loop resonator (ASLR). An added outer square loop is designed to play the roles of both a metamaterial and a micro-heater, which can control the temperature through a directly applied bias voltage. A vanadium dioxide ($VO_2$) thin film, which exhibits an insulator-metal phase transition with temperature change, is used to control the transmission properties. The proposed ASLR-OSL shows transmission properties similar to those of the ASLR, and they can be successfully controlled by directly applying bias voltage to the outer square loop. Based on these results, an electrically controllable terahertz high-Q metamaterial could be achieved simply by adding a square loop to the outside of a well-known high-Q metamaterial.

Caregiver or Family Doses due to Discharged $^{131}I$ Administrated Patient from the Hospital (고용량 $^{131}I$ 투여환자 퇴원이후 환자 간병인과 환자 가옥의 피폭선량 측정)

  • Jeong, Gyu-Hwan;Lee, Hyun-Kook;Cho, Woon-Kap;Lee, Jai-Ki
    • Journal of radiological science and technology
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    • v.33 no.2
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    • pp.149-154
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    • 2010
  • Exposed doses to the patient's caregiver and their house due to the 131I from patients discharged from the hospital were measured using OSL dosimeters. Usually, 3.37-5.55 GBq (100-150 mCi) of $^{131}I$ administrated patients are discharged from the hospital after 3 or 4 days of hospitalization in Korea. In addition, after 5 to 8 days, the accumulated doses of the patient's caregiver and house after hospitalization of the patient were measured using OSL dosimeters. The results of the measured average accumulated doses were 0.1 mSv, which is 10% of 1 mSv, the public dose limit in the Korean Atomic Energy Law. And it's standard deviation was 0.087 mSv. Based on the results of this study, we anticipate that we could assure the compliance of the regulation requirement 5 mSv of MEST (Ministry of Education, Science and Technology) Notice No. 2008-45 for the patient's caregiver or family, even if we reduce the 3-4 days of hospitalization to 1-2 days or less.

The Origin of Paleo-Lacustrine Deposits at Yeoncheon in Chugaryeong Rift Valley, Central Korea (추가령 열곡 연천 고호소층의 퇴적물 기원지 분석)

  • Lee, Min-Boo;Lee, Gwang-Ryul;Kim, Nam-Shin
    • Journal of the Korean Geographical Society
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    • v.42 no.1 s.118
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    • pp.15-26
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    • 2007
  • This study aims to estimate the similarities of lacustrine deposits of lava-dammed Yeoncheon paleo-lake by geochemical analysis such as XRF, ICP-AES, and 14C and OSL age datings in Chugaryeong Rift Valley of Central Korea. OSL age of the lacustrine coastal deposit(YC1) is estimated as 0.11-0.13 Ma. It indicates that paleo-deposits may have remained during at least 20,000 years from 0.13 Ma The origin analysis of deposits were carried out by comparison between lacustrine mud layers($YC1{\sim}2$) and various geomorphic materials of vicinity As a result, the similarity of the origin is highest between the paleo-coastal alluvial deposit of Chatan River(YC8), and surface clay deposit of Jeongok lava plateau(YC9) Next higher similarity is between paleo-lacustrine bottom deposit(YC2) and west valley-side mountain slope colluvial materials(YC5). Another high similarities are among present Chatan River channel sediment(YC7), acustrine coastal deposit(YC1) and east valley-side mountain slope colluvial materials(YC4).

Characteristics and depositional environment of paleosol layers developed on top of the terrace in the Jeongdongjin area, East Coast, Korea (강릉 정동진 지역 단구 고토양층의 특징과 퇴적 환경)

  • Yi, Seon-Bok;Lee, Yong-Il;Lim, Hyun-Soo
    • The Korean Journal of Quaternary Research
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    • v.23 no.1
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    • pp.1-24
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    • 2009
  • Paleosol layers lying on top of the terrace in Jeongdongjin area appear to have been deposited under generally well-drained condition with periodic waterlogging. From a 4.5m-long profile observed, a total of 6 stratigraphic units were identified. Grain-size analysis indicates the dominance of silty and clay materials with some portions with high sand content. Major mineralogical elements are quartz, feldspar, mica and chlorite. Geo-chemical composition shows little change throughout the stratigraphy with some fluctuation in chemical weathering index. Marked increase in magnetic susceptibility is recognizable where stratigraphic unit changes. Soil- wedge layer is developed around 50cm below the surface with concentration of grains of AT tephra (c. 25,000 BP). An OSL date of c. 110,000 BP was obtained from a sand layer lying below the paleosol.

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