• Nuclear Engineering and Technology
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• v.3 no.1
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• pp.15-19
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• 1971

High specific activity $^{51}$ Cr is mainly prepared by Szilard-Chalmers process from $K_2$CrO$_4$target. Usually the recoil atom, Cr* (III), is coprecipitated with Fe(III) as a scavenger to be separated from $K_2$CrO$_4$. A new preparation method has been developed, by adding 0.1N NaOH and $C_2$H$^{5}$ OH to the irradiated target solution, to precipitate Cr* (III) without any scavenger such as Fe(III). The new method gives the product of higher specific activity and better yield than that of other methods, in the shorter processing time. This method is compared with the conventional method and the French method, and following results are obtained: the new method gives specific activity more than twice that of the conventional method and better yield than the conventional method : the French method and the new method give similar specific activity, but yield of the new method is almost twice that of the French method.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.752-756
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• 1998

산업용 및 의료용으로 사용되는 $^{192}$ Ir 방사선원에 대한 $\psi$선 자기흡수효과인자를 실험을 통하여 구하였다. 이를 위하여 3 mm $\psi$ x 3 mm t, 2.5 mm $\psi$ x 2.5 mm t, 2 mm $\psi$ x 2 mm Ir의 원주형 Ir 표적과 3 mm $\psi$ x 0.25 mm t, 3 mm $\psi$ x 0.1 mm t의 원판형 Ir 표적을 하나로의 PTS(Pneumatic Transport System)조사공에서 중성자 조사하였다. 이온전리함을 사용하여 각 Ir 표적의 방사능을 측정하고 계산에 의해서 구한 생성방사능 값과의 비를 구하는 방법으로 $^{192}$ Ir의 ${\gamma}$선 자기흡수효과인자를 구하였다. 이 값들은 원주형 표적에 대하여 각각 0.614, 0.687, 0.704 였고 원판형 표적에 대하여 각각 0.827, 0.875 였다. 원주형 Ir 표적내부의 중성자 자기흡수효과의 정도를 알아보기 위하여 2.5 mm $\psi$ x 0.25 mm t Ir 표적 10장을 포개어 중성자 방사화시킨 후 각 표적의 방사능을 측정한 결과 가장 바깥쪽 표적의 방사능이 중심부에 위치한 표적보다 약 2배정도 방사화가 많이 일어남을 알 수 있었다. 이번에 구한 ${\gamma}$선 자기흡수효과인자는 향후 산업용 및 의료용으로 사용되는 $^{192}$ Ir 방사선원의 사용자에게 제공되는 최종방사능을 평가하는데 유용하게 사용될 수 있다.

• The Korean Journal of Nuclear Medicine Technology
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• v.17 no.1
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• pp.67-70
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• 2013

Purpose: Surge in patients with hepatocellular carcinoma, hepatic artery chemical embolization is one of the effective interventional procedures. The PET/CT examination plays an important role in determining the presence of residual cancer cells and metastasis, and prognosis after embolization. The other hand, the hepatic artery chemical embolization of embolic material used lipiodol produced artifacts in the PET/CT examination, and these artifacts results in quantitative evaluation influence. This study, the radioactivity density and the percentage error was evaluated by the extent of the impact of lipiodol in the image of PET/CT. Materials and Methods: 1994 NEMA Phantom was acquired for 2 minutes and 30 seconds per bed after the Teflon, water and lipiodol filled, and these three inserts into the enough to mix the rest behind radioactive injection with $20{\pm}10MBq$. Phantom reconfigure with the iterative reconstruction method the number of iterations for two times by law, a subset of 20 errors. We set up region of interest at each area of the Teflon, water, lipiodol, insert artifact occurs between regions, and background and it was calculated and compared by the radioactivity density(kBq/ml) and the% Difference. Results: Radioactivity density of the each region of interest area with the teflon, water, lipiodol, insert artifact occurs between regions, background activity was $0.09{\pm}0.04$, $0.40{\pm}0.17$, $1.55{\pm}0.75$, $2.5{\pm}1.09$, $2.65{\pm}1.16 kBq/ml$ (P <0.05) and it was statistically significant results. Percentage error of lipiodol in each area was 118%, compared to the water compared with the background activity 52%, compared with a teflon was 180% of the difference. Conclusion: We found that the error due to under the influence of the attenuation correction when PET/CT scans after lipiodol injection performed, and the radioactivity density is higher than compared to other implants, lower than background. Applying the nonattenuation correction images, and after hepatic artery chemical embolization who underwent PET/CT imaging so that the test should be take the consideration to the extent of the impact of lipiodol be.

• Environmental and Resource Economics Review
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• v.22 no.3
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• pp.411-435
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• 2013

Since catastrophe from explosion of Hukushima nuclear power plant, concerns over possibility of exposure to radioactive matter has been disseminating all over the world and frequent accidents of domestic nuclear power plants also has been amplifying throughout the nation. In the past, major focus was made on compensation for local residents who live nearby nuclear power plants, but focal point of this study is on wage premium of workers who are employed in R&D of nuclear power plants. It is difficult to derive socially desirable result if private sectors are responsible for compensation on workers who suffer from physical damages due to the exposure to radioactive matter. Because victims should verify the damages that occur in the working places. This study conducted a survey on which job would prefer the respondents who are engaged with the nuclear R&D projects as exposure levels to radioactive matter, security of job, location of firms, and work intensity differ. As a result, exposure to radioactive matter was the most important attribute in choosing alternative jobs followed by job security, work intensity and job location. Annual willingness to pay for reduction of exposure to radioactive matter was estimated as 7730~7770 thousand KRW depending on different econometric models. Therefore, Korean government should prepare institutional foundation in order that appropriate compensation should be made on workers who are engaged in R&D projects on nuclear power plants if they have damages from the exposure to radioactive matter.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.92-97
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• 1995

감염병소와 진단을 위해 여러 방사성성핵종 표지 사람비특이항체들이 임상이용되었으나, $^{123}I,\;^{99m}Tc,\;^{111}In$등 표지 핵종과 표지방법에 따른 체내동태의 차이에 대한 자료가 필요하며, 감염병소의 진단에 표준적으로 이용되어지던 $^{111}In$-oxine표지백혈구와 비교평가도 요구된다. 저자들은 $10^9$개의 포도상구균을 좌측 대퇴부에 주사하여 농양을 유발한 백서에서 $^{123}In$ 표지, iminothiolane을 이용한 $^{99m}Tc$ 표지, DTPA이용 $^{111}In$ 표지 사람비특이항체와 $^{111}In$-oxine 표지 백혈구의 체내동태 및 농양섭취율을 비교하였다. $^{123}In$-IgG는 갑상선 및 위의 방사능이 높아 체내 탈요드반응이 빠름이 시사되었으며, $^{99m}Tc$-iminothiolane IgG는 신장방사능이 높아 신장으로 IgG 또는 대사물이 배설됨을 알 수 있었다. $^{111}In$-oxine표지 백혈구는 간 및 비장의 방사능이 높았고, 혈액방사능 제거율이 가장 빨랐다. 주사 24시간 후의 농양섭취율은 $^{111}In$-DTPA IgG가 가장 높았고, 농양 대 혈액 방사능비는 $^{111}In$-oxine표지 백혈구가 가장 높았으며, $^{111}In$-DTPA IgG와 $^{99m}Tc$-iminothiolane IgG가 다음으로 비슷하였다. $^{111}In$-oxine표지 백혈구보다는 방사성핵종표지 IgG가 간편하게 이용될 수 있으며, $^{111}In$ 이 $^{99m}Tc$나 $^{123}In$보다 지연영상의 촬영에 유리함을 알 수 있었다.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.261-269
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• 1993

When monoclonal antibodies are used in radioimmunoassay or immunoscintigraphic studies, post-labelling immunoreativity is a critical parameter. $^{125}I$ was incorporated to CEA-79 (anti CEA monoclonal antibody developed in Korea) by chloramine T and iodogen method with variable specific activities from $0.1{\mu}Ci/{\mu}g$ to $100{\mu}Ci/{\mu}g$. We used a new method to evaluate the immunoreactivites of modified antibody relative to the unlabelled native antibody from competitive binding assay. The effect of immunoreactivity and specific activity to the sensitivity of radioimmunometric assay was also evaluated. As a result, chloramine T method was better than iodogen method in radioiodination of CEA-79, because the immunoreactivity of antibody was relatively well reserved and more stable. New competitive binding assay was simple and effective to evaluate the change of immunoreactivity in radiolabelling. Antibody with high immunoreactivity and high specific activity improved the sensitivity of radioimmunometric assay, whereas antibody with high specific activity but low immunoreactivity didn't. The immunoreactivity and specific activity should be optimized according to the clinical un, and competitive binding method is useful in selection of optimal radiolabelling assay.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.216-223
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• 2000

In order to study origin and mixing ratio of surface water masses in the East China Sea (ECS), the South Sea of Korea and the Korea Strait, we use three end-member mixing equation. We use $^{228}$Ra/$^{226}$Ra activity ratio and salinity as two conservative tracer and the Changjiang Water (CW), the Yellow Sea Water (YSW), and the Kuroshio Water (KW) as three end members, Results show that ECS surface water includes all the three end member water, in the order of KW (50-90%), YSW (20-40%) and CW (0-20%) in August 1997. Also, the amount of CW can be approximately estimated by salinity alone. Surface water of the South Sea and the Korea Strait includes very small or almost no CW (below 2% except station 9) in May 1998. Thus in the Korea Strait mixing ratio could be estimated by $^{228}$Ra/$^{226}$Ra activity ratio tracer alone between two end-members, KW and YSW. However, in order to Set more accurate results or in case of rainy season, a mixing equation based on two tracers and three end-members is required.

• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.19-34
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• 1996

[ $[^{123}I]{\beta}$ ]-CIT [$2{\beta}$-carbomethoxy-$3{\beta}$-(4-iodophenyl)tropane]는 도파민 운반체 (dopamine transporter)에 특이결합하며 $[^{123}I]{\beta}$-CIT의 도파민 운반체 결합정도는 파킨슨병에서 도파민 뉴우런의 변성정도를 반영하는 것으로 제안되어 왔다. 이 연구의 주요 목적은 파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT SPECT를 이용하여 측정된 $[^{123}I]{\beta}$-CIT의 선조체 결합지표들이 질병의 임상적 진행정도를 반영하는지를 검토하고, 간편화된 조직방사능비가 $[^{123}I]{\beta}$-CIT의 결합정도를 나타내는 정량적 지표로 이용될 수 있는지를 검증하는 것이었다. 파킨슨병 환자 30명($59{\pm}9$세, 평균${\pm}$표준편차: Hoehn-Yahr stage 1-3)과 정상인 6명 ($58{\pm}5$세)을 대상으로 $[^{123}I]{\beta}$-CIT SPECT 영상을 얻었다. $[^{123}I]{\beta}$-CIT 선조체 결합의 정량적 지표로서 (선조체 방사능-소뇌방사능)/소뇌방사능 비(specific binding ratio, SBR)와 추적자역학모델을 이용하여 측정한 선조체 결합능(binding potential)($k_3/k_4$)을 구하였다. 파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT의 선조체 결합역학은 정상인에 비하여 현저하게 느렸으며 그 결합지표들은 정상인에 비하여 뚜렷하게 낮았다. 한편, 편측파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT 결합은 증상 반대쪽 선조체 뿐만 아니라 같은 쪽 선조체에서도 정상인에 비해 유의하게 감소되어 있었다. 파킨슨병 환자에서 $[^{123}I]{\beta}$-CIT 투여 후 24시간의 선조체 SBR 및 최대 SBR, 선조체 결합능은 모두, 유병기간, Hoehn-Yahr stage, UPDRS(Unified Parkinson's Disease Rating Scale) 총점, UPDRS 운동점수, UPDRS 일상활동점수와 유의한 상관관계를 나타내었다. 24시간 선조체 SBR과 최대 SBR은 선조체 결합능과 우수한 상관관계를 보였다. 이상의 결과로부터 $[^{123}I]{\beta}$-CIT의 선조체 결합은 파킨슨병의 진행정도를 나타내는 지표로 이용될 수 있다. 또 $[^{123}I]{\beta}$-CIT 투여 후 24시간 영상으로부터 얻은 간편화된 조직방사능 비는 $[^{123}I]{\beta}$-CIT의 결합정도를 정량적으로 반영한다. $[^{123}I]{\beta}$-CIT SPECT는 파킨슨병의 조기진단 및 진행 추적에 임상적으로 유용할 것으로 판단된다.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.49-55
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• 2012

Asynchronous counters, where the counter value is changed not by a synchronizing clock but by outer inputs, are used in various modern digital systems such as spaceborne electronics. In this paper, we propose a scheme of fault tolerance for asynchronous counters with critical races caused by total ionizing dose (TID) in space. As a typical design flaw of asynchronous digital circuits, critical races cause an asynchronous circuit to show non-deterministic behavior, i.e., the next stable state of a state transition is not a fixed value but may be any value of a state set. Using the corrective control scheme for asynchronous sequential machines, this paper provides an existence condition and design procedure for a state feedback controller that can invalidate the effect of critical races. We implement the proposed control system in VHDL code and conduct experiments to demonstrate that the proposed control system can overcome critical races.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.415-415
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• 2001