• 전자공학회논문지
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• 제52권2호
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• pp.173-181
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• 2015

연구에서는 진단 및 수술 후 잔여병소의 검출을 위하여 방사선계수 방식의 무선 감마선 프로브를 개발하고, 교정선원과 팬텀을 이용하여 그 유용성을 평가 하였다. 반도체기반 방사선센서를 사용하여 프로브 설계 및 소형화 하였으며, 블루투스 원격통신 모듈을 사용하여 진단 및 검출 시스템의 무선화를 구현하였다. 또한 진단 및 수술 시 환부의 모니터링이 가능한 원격모니터링 시스템을 구현하였다. 개발된 프로브의 유용성 평가를 위해 교정선원 $^{57}Co$, $^{133}Ba$, $^{22}Na$, $^{137}Cs$과 닭 가슴살 팬텀을 사용하였다. 평가를 통해 감마선에 대한 프로브의 검출 반응성을 확인하였고, 감마선 세기에 따른 응답 선형성과 검출 방향성, 팬텀 내 선원 깊이에 따른 프로브의 검출효율을 평가를 통해 실증적인 임상에서의 적용 가능성을 확인하였다.

• 천문학회보
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• 제39권2호
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• pp.113.1-113.1
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• 2014

We propose a three-year Key Science Program (KSP) consisting of VLBI monitoring observations and single dish (SD) rapid response observations (RRO). The VLBI monitoring observations are comprised of ten 24-hr observations per year (every month) of about 30 gamma-ray brigt active galactic nuclei (AGNs) with Korea VLBI Network (KVN) at 22, 43, 86, and 129 GHz. The SD RROs may consist of twelve 7-hr observations per source (every week for 3 months after triggering) of gamma-ray flaring sources with two KVN SD telescopes at 22, 43, and 86 GHz in dual polarization. We expect one or two sources per year for the SD RROs. Gamma-ray flares of AGNs are known to be occured in innermost regions of relativistic jets which radiate in whole ranges of electromagnetic spectra due to synchrotron radiation, syschrotron self absorption, inverse-compton scttering, doppler boosting etc. Possible explanations of the gamma-ray flares in AGNs are a) shocks-in-jets propagating within jet flow and b) bending of the whole jets. For both cases, we should expect changes in polarization, luminosity, particle distribution, and structures of jets at mas-scale. The multifrequency simultaneous VLBI/SD observations with KVN are the best tool for detecting such changes correlated with gamma-ray flares. This KSP proposal aims to answer the fundamental questions about the basic nature of the flares of AGNs.

• 센서학회지
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• 제27권4호
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• pp.232-236
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• 2018

A radiation detection sensor was developed and characterized by combining three types of CsI(Tl) scintillators and an array-type SiPM to detect the radioactive contamination of discharged water in real time. The characterization results showed that type 3 exhibited the most desirable characteristics in response linearity (R-square: 0.97889) according to detection sensitivity and incident radiation dose. Furthermore, in terms of spectral characteristics, type 3 exhibited 16.54% at 0.356 MeV (the emission gamma ray energy of $^{133}Ba$), 10.28% at 0.511 MeV (the emission gamma ray energy of $^{22}Na$), 9.68% at 0.356 MeV (the emission gamma ray energy of $^{137}Cs$), and 2.55% and 4.80% at 1.173 MeV and 1.332 MeV (the emission gamma ray energies of $^{60}Co$), respectively. These measurements confirmed the good energy characteristics. The results were used to evaluate the spectral characteristics and energy linearity in a mixed source using type 3 with the best detection characteristics. It was confirmed that the gamma ray peaks of $^{133}Ba$, $^{22}Na$, $^{137}Cs$, and $^{60}Co$ were well resolved. Moreover, it was confirmed that R-square, which is an indicator of energy linearity, was 0.99986. This indicates a good linearity characteristic. Based on this study, further commercialization studies will contribute to measurements in real time and to the management of the contamination caused by radioactive wastewater or radioactive material leakage, which originate from facilities that use radioactive isotopes or care facilities.

• 한국미생물·생명공학회지
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• 제1권2호
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• pp.105-113
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• 1973

1) 탄소원으로서 glucose medium에서 Brevibacterium flavum을 배양할때 Biotin 5${\gamma}$/1, Desthiobiotin 5${\gamma}$/1, 7.8-Diaminopelargonic acid 10${\gamma}$/l 에서 L-GA생성이 가장 양호하였다. 2) 탄소원으로서 glucose-acetate혼합배지를 4구분하여 사용한 결과 생육도, L-GA생성은glucose 2%-acetate 혼합배지가 가장 양호하였다. 3) 탄소원으로서 Methanol, Ethanol, Ethylacetate, Acetic acid (free acetate), Na-acetate :NH$_4$-acetate=2 : 1의 배지를 사용한 결과 Na-acetate : NH$_4$-acetate=2 : 1 > Acetic acid (free acetate) > Ethylacetate > Ethanol> Methanol 의 순으로 L-GA 생성이 나타났다. 4) 생장촉진제로 각종 Biotin vitamer를 첨가하고 탄소원으로 glucose 또는 Acetate 배지를 사용하였을때 요구되는 농도는 Biotin에 대하여 Desthiobiotin은 대략 동양, 7.8-Diaminopelargonic acid는 3~4배 였으며 Bisnorbiotin은 대체효과가 없었다.

• 비파괴검사학회지
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• 제14권4호
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• pp.228-236
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• 1995

본 연구에서는 비파괴검사 방법의 하나인 gamma scanning test에 의한 대단위 차폐체의 결함을 평가하는 방법을 제시하고 방사선 차폐를 해석하는 유용한 방법중의 하나인 Monte Carlo 코드로 이에 대한 검증을 하였다. Gamma scanning test로 차폐체의 결함을 평가하기 위한 모델은 원통형 차폐체를 대상으로 하였다. 먼저 방사성물질 운반용기에 대한 설계기준에 따라 기준차폐체를 설치하여 Co-60 선원과 섬광계수기로 기준치를 측정하고, 그 다음 실물의 원통형 차폐체를 측정하였다. 기준치로 원통형 차폐체의 납두께를 환산한 결과 결함두께는 최대 12mm로 평가되었다. 이를 검증하기 위한 MCNP 코드의 계산에서는 결함두께가 실험적 결과에 비해 4.1%에 해당하는 최대 11.6mm를 나타내었으며, 두 결과가 만족할 정도로 일치함을 보여주고 있다. 따라서 이러한 평가방법은 방사성물질을 사용하는 시설에 설치되는 대단위 방사선 차폐체나 대용량의 운반용기 차폐능 검사시 현장에서 적용시킬 수 있으며 측정치의 신뢰도를 제고할 수 있다. 앞으로 보다 정확한 측정을 위하여 차폐체의 두께 측정결과가 화면에 직접 표시되는 측정장치의 연구 개발이 요구된다.

• 미생물학회지
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• 제5권2호
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• pp.79-85
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• 1967

Kim, Jong Hyup., (Div. of Biology, Atomic Energy Research Institute,Korea.;) Studies on the Cellulor Metabolism in Microorganisms as influenced by Gamma-irradiation(III): On the Changes of Free Amino acid Pool and content of Protein in Yeast clls irradiated by .gamma.-ray. 1. The strain of Saccharomyces cerevisiae had been cultured synchronously in aerobic condition and irradiatel by gamma-ray from the source of cobalt-60. Drying in vacuum oven at $90^{\circ}C$ C over 12 hours, then changes of protein content (Kjeldahl) and free amino acid pool have been assayed with use of spectrophotometer. Results obtained were compared with those of unirradiated normal cells. 2. It is proved that amount of protein content in the irradiated cells increases to seven percent more than those of normal cells in the same weight of dried samples. It seems like carbohydrate breakown had been stimulated by irradiation and that relative contents of protein shows higher values than those of normal in the same weight of samples. 3. The amount of free amino acid pool in the irradiated cells shows less value about ten percent than those of normal cells, and rate of decreasing is also weak than those of standard reagent solution of amino acid. We may assume that free amino acid pool would be protected against radiation damage in living cells and more stable than in vitro. 4. The component of free amino acid pool have been assayed on second dimensional paper chromatogram, and the identified amino acids are as follows; aspartic acid, serine, glutamic acid, cystine, lysine, glycine, threonine, histidine, arginine, tyrosine, phenylalanine, valine and leucine. 5. Distributional presence of free amino acids are identical to that of normal cells except arginine, it is cosumable that radiation effect is univerlsal to all amino acid. However it is obvious that there are differences in radiolabilities of amino acids in irradiated cells.

• 한국식품영양과학회지
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• 제28권3호
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• pp.646-653
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• 1999

This study was done to investigate the effect of ${\gamma}$ irradiated beef feeding on antioxidant vitamin levels and defense enzyme activities in diethylnitrosamine(DEN) initiated rats. Weaning Sprague Dawley male rats were fed the diet containing ${\gamma}$ irradiated ground beef at the dose 0, 3, 5 kGy as a 20% of protein source for 8 weeks. One week after feeding, rats were intraperitoneally injected twice with a dose of DEN(50mg/kg BW). As a promoter, 0.05% phenobarbital was fed in drinking water from one week after DEN treatment until the end of experiment. At the end of 8th week, serum level of vitamin C, serum and hepatic levels of retinol and tocopherol were determined. In addition, activities of cytosolic glutathione peroxidase, glutathione reductase, glutathione S transferase, catalase and hepatic superoxide dismutase(SOD) were measured. By ${\gamma}$ irradiation, there was no significant effect on serum and hepatic levels of vitamin C and tocopherol except a significant decreasing effect on hepatic retinol level. There was also no significant effect on the activities of enzymes involved in antioxidative defense system, However, DEN treatment led to a significant increase in activities of glutathione reductase and glutathione S transferase while the activity of glutathione peroxidase was decreased. The activities of hepatic SOD and catalase were not changed by DEN treatment. Overall results indicate that the consumption of low dose of ${\gamma}$ irradiated beef does not affect antioxidative defense system.

• 한국축산식품학회지
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• 제30권3호
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• pp.397-402
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• 2010

Pork is an excellent source of essential nutrients such as protein. However, pork can trigger hypersensitivity and serum albumin of pork is known as major allergen. In this study, to evaluate the effect of gamma irradiation on the allergenicity of porcine serum albumin (PSA), PSA solution was irradiated at 3, 5, 7, 10, 15, and 20 kGy. The changes in the ability of PSA to bind IgG and patient's serum caused by gamma irradiation were observed by ci-ELISA and immunoblotting. SDS-PAGE was used for measuring the conformational change of gamma-irradiated PSA. The ability of 3-kGy-irradiated PSA to bind p-IgG and patient's serum was decreased to 30% and 15%, respectively. The binding ability showed no significant differences among all irradiated samples. SDS-PAGE showed that the irradiated PSA bands were degraded and aggregated. Immunoblotting of irradiated PSA revealed that IgG and patient's serum were rarely recognized at 3 kGy. Therefore, gamma irradiation could be applied to less-allergenic pork products.

• Nuclear Engineering and Technology
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• 제55권7호
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• pp.2613-2620
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• 2023

Excellent thermal neutron absorption performance of boron expands the potential use of boron rich slag to prepare epoxy resin matrix nuclear shielding composites. However, shielding attenuation behaviors and mechanism of the composites against gamma rays are unclear. Based on the radiation protection theory, Phy-X/PSD, XCOM, and ⁶⁰Co gamma ray source were integrated to obtain the shielding parameters of boron rich slag/epoxy resin composites at 0.015-15 MeV, which include mass attenuation coefficient (µ_t), linear attenuation coefficient (µ), half value thickness layer (HVL), electron density (N_eff), effective atomic number (Z_eff), exposure buildup factor (EBF) and exposure absorption buildup factor (EABF).µ_t, µ, HVL, N_eff, Z_eff, EBF and EABF are 0.02-7 cm²/g, 0.04-17 cm^-1, 0.045-20 cm, 5-14, 3 × 10²³-8 × 10²³ electron/g, 0-2000, and 0-3500. Shielding performance is BS4, BS3, BS3, BS1 in descending order, but worse than ordinary concrete. µ and HVL of BS1-BS4 for ⁶⁰Co gamma ray is 0.095-0.110 cm^-1 and 6.3-7.2 cm. Shielding mechanism is main interactions for attenuation gamma ray by BS1-BS4 are elements with higher content or higher atomic number via Photoelectric Absorption at low energy range, and elements with higher content via Compton Scattering and Pair Production in Nuclear Field at middle and higher energy range.

• 한국방사선학회논문지
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• 제12권5호
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• pp.557-563
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• 2018

동시 합성 보정 효과는 검출기의 효율이 향상할 때 그리고 선원과 검출기 사이의 거리가 가까울수록 크게 나타나는 것으로 알려져 있다. 점 선원($^{60}Co$)을 사용하여 검출기 중심축 방향 및 방사상 방향에서 거리에 따른 변화를 주어 P/T 비를 구하여 동시합성 보정을 하였다. 따라서 본 연구에서는 중심축 및 방사상 방향에서 동시합성 보정한 값들을 혼합부피선원(450 mL CRM source)에 적용하여 P/T에 따른 전체 피크효율 변화를 Geant4과 비교하였다. 또한 검출기와 시료가 아주 밀착된 상태에서 맵핑법에서 구한 효율을 환경시료 중에서 해양 시료인 미역에 적용하여 P/T 비의 적합성을 평가하고자 한다. 500 keV 이상의 효율의 영향을 받는 에너지 영역에 1,836 keV로 보정한 효율을 적용한 결과 측정값과 보정값의 상대오차는 3.2 % peak 효율이 보정되어 잘 일치하였다. 450 mL CRM source처럼 부피가 커질수록 P/T 비는 ${\pm}5%$까지 감소하였다. 이것은 검출기로부터 선원이 멀어짐에 따라 방출된 감마선의 산란이 많아지기 때문이며, 이처럼 P/T 변화는 동시합성 보정 피크 효율에 영향을 줌을 확인하였다.