• 미생물학회지
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• 제13권2호
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• pp.64-70
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• 1975

As a serial experiment of radiosterilization of medical products, we investigated the feasibility of using gamma ray to sterilize antibiotics, tetracycline HCl. Tetracycline HCl in aqueous solution and dried state irradiated with several dose levels was assayed for physico-chemical properties by checking UV absorption spectra, paper chromatogrph. IR spectra and NMR sepctra, and antibiotic activities by [means of agar plaque technique and tube $d_1$]ution method. In physico-chemical propertis and biological activities, the teracycline HCl in dried state remained radioresistant up to exposure of 10 Mrad, however, in aqueous solution, the dose of 300 Krad produced a significant inactivation. From the results of this study, radiosterilization of tetracycline HCl is more recommendable in the dried state than in aqueous solution.

• 한국안전학회지
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• 제20권1호
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• pp.81-86
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• 2005

This study has investigated radiation degradation of low density polyethylene(LDPE). Samples were irradiated up to 800kGy using a $Co^{60}\;\gamma-ray$ at a dose rate of 5kGy/hr in the presence of air atmosphere at room temperature. After irradiation, storing for 2 weeks, free radical measurement of LDPE has established by electron spin resonance(ESR). ESR measurement showed that free radical concentration(FRC) was increased with radiation dose and decreased with the time. The radical types showed alkyl, allyl, and peroxy radical with the irradiation, these changed to peroxy radical with the time.

• Journal of Radiation Protection and Research
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• 제19권1호
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• pp.37-50
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• 1994

X-선과 감마선의 에너지에 따른 선질특성과 선량 및 필름의 사진농도와의 관계를 이용한 필름배지선량계의 선량환산식을 실험적으로 체계화 하였고, 시간경과에 따른 잠상퇴행 특성과 방사선의 입사방향에 따른 방향특성을 실험적으로 조사하여 보정계수를 산출하였다. 본 연구에서 구한 선량환산식은 필름배지선량계의 기술기준인 성능판정 기준을 잘 만족시키는 것으로 나타났다.

• 대한전자공학회논문지
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• 제27권4호
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• pp.604-611
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• 1990

One of the confronting problems in using optical fibers under radiation environments is producing of color centers in optical materials due to nuclear radiation. These centers increase transmission loss by absorbing propagating light. In this study, the radiation effects on optical fiber are studied theoretically. Also, optical attenuation induced by \ulcorner-ray irradiation from Co**60 for single mode and multimode optical fibers is measured at the optical wavelength of 0.85\ulcorner and 1.3\ulcorner, and the results are analyzed. Gammaray is irradiated for 5hours at the rate of 300rads/min, which is corresponding to 90 krads of integrated dose. In case of multimode optical fibers, the induced loss at 0.85\ulcorner wavelength has been twice higher than that at 1.3\ulcorner. The loss in multimode fibers has been significantly larger by 7-20 times than that in single mode fibers, dependently on fiber materials at 1.3\ulcorner.

• 한국전기전자재료학회논문지
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• 제17권11호
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• pp.1205-1211
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• 2004

This study has investigated radiation degradation of chloroprene rubber in the presence of some fire retardant. Ammonium polyphosphate, aluminium trihydroxide, magnesium hydroxide, calcium carbonate and antimony trioxide were selected as flame retardant. Samples were irradiated using a Co$^{60}$ ${\gamma}$ -ray and ray up to 2000 kGy at a dose rate of 5 kGy/hr in the presence of air atmosphere at room temperature. After irradiation, samples were assessed fire retardancy with electrical properties and mechanical properties. Some considerations concerning the effects of the fire retardants added to chloroprene rubber on the radiation and thermal stability of chloroprene rubber are presented. From fire retardancy with electrical and mechanical property measurements, it was found that addition of magnesium hydroxide resulted in maximum fire retardant effect.

• 방사선산업학회지
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• 제2권1호
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• pp.15-19
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• 2008

In order to develop a water-solubility and biocompatibility, chemically modified chitosan, N,O-carboxymethylchitosan (NOCC), was synthesized and the NOCC hydrogels were prepared by using ${\gamma}-ray$ irradiation instead of chemical reagents. The FT-IR spectroscopy, swelling behavior, gel content and mechanical property such as gel strength of the hydrogel were measured. When the NOCC solution concentration was 15 wt% and the dose of irradiation was less than 50 kGy, the NOCC hydrogels had an excellent hydrophilicity and exhibited a good swelling behavior and mechanical properties.

• 전기학회논문지
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• 제66권3호
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• pp.540-544
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• 2017

In this study, we analyzed the effects of TID(Total Ionizing Dese) and TREE(Transient Radiation Effects on Electronics) on nMOSFET and pMOSFET fabricated by 0.18um CMOS process. The size of nMOSFET and pMOSFET is 100um/1um(W/L). The TID test was conducted up to 1 Mrad(Si) with a gamma-ray(Co-60). During the TID test, the nMOSFET generated leakage current proportional to the applied dose, but that of the pMOSFET was remained in a steady state. The TREE test was conducted at TEST LINAC in Pohang Accelerator Laboratory with a maximum dose-rate of $3.16{\times}10^8rad(si)/s$. In that test nMOESFET generated a large amount of photocurrent at a maximum of $3.16{\times}10^8rad(si)/s$. Whereas, pMOSFETs showed high TREE immunity with a little amount of photocurrent at the same dose rate. Based on the results of this experiment, we will progress the research of the radiation hardening for CMOS unit devices.

• 방사성폐기물학회지
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• 제21권4호
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• pp.543-558
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• 2023

Currently, Japan is undertaking a nationwide project to measure and map radioactive contamination around Fukushima, as part of the efforts to restore normalcy following the nuclear accident. The Japan Atomic Energy Agency (JAEA) manages the Fukushima Environmental Safety Center, located approximately 20 km north of the Fukushima Daiichi nuclear power plant in Minamisōma City, Fukushima Prefecture. In collaboration with the JAEA, this study involved conducting comparison experiments and analyses with radiation detectors in high radiation environments, a challenging task in Korean environments. Environmental radiation surveys were conducted using three types of detectors: CZT, NaI(Tl), and LaBr₃(Ce), across two contaminated areas. Dose rate values were converted using dose rate conversion factors for each detector type, and dose rate maps were subsequently created and compared. The detectors yielded similar results, demonstrating their feasibility and reliability in high radiation environments. The findings of this study are expected to be a crucial reference for enhancing the verification and supplementation of procedures and methods in future radiation measurements and mobile surveys in high-radiation environments, using these three types of radiation instruments.

• 한국방사선학회논문지
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• 제16권6호
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• pp.681-686
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• 2022

본 연구에서 상용 아크릴 기반 레진에 PPO 유기섬광체 및 MMA를 각각 1 wt% 및 5 wt% 첨가하여 3D 프린팅이 가능한 섬광체 레진을 제작하였다. 개발된 섬광체 레진을 사용하여 상용 3D DLP로 간편하면서도 저렴하게 3D 모양의 플라스틱 섬광체 방사선 센서를 성공적으로 제작할 수 있었다. 제작된 센서는 45 MeV 양성자 빔의 빔 전류 1 ~ 10 nA 범위에서 R제곱값이 0.998로 우수한 선량 대 출력 직선성을 보였다. 개발된 3D 플라스틱 섬광체는 광출력이 낮아서 저선량율 감마선이나 X선 선량 측정에 활용하기에는 제한이 있지만, 조직등가물질로서 인체흡수선량을 직접 측정할 수 있기 때문에 양성자 빔, 초고선량율 빔 등 고에너지 또는 고선량율 방사선 선량 측정에 유용하게 활용될 수 있음을 확인하였다.

• 한국식품저장유통학회지
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• 제21권3호
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• pp.315-320
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• 2014

본 연구에서는 후춧가루의 위생화를 위해 감마선, 전자선 및 X-선을 조사한 후 이에 따른 미생물학적 및 관능적 품질변화를 평가하였다. 후춧가루에 감마선, 전자선 및 X-선을 2, 4, 6, 8 및 10 kGy로 각각 조사한 후 미생물 변화와 관능품질 변화를 평가한 결과, 미생물의 경우 선종에 관계없이 흡수선량이 증가할수록 미생물 제어 효과가 증가하는 것으로 나타났으며, 선종별 D10값의 경우 2.24-2.75 kGy범위를 보였으며 방사선 선종에 따른 유의차가 없는 것으로 나타났다. 색도의 경우 명도, 적색도 및 황색도 모두 방사선 선종에 따른 변화가 없는 것으로 판단하였다. 관능적 품질 역시 방사선 선종에 관계없이 흡수선량에 따라 품질저하가 발생되는 것으로 나타났다. 이상의 결과를 종합하여 볼 때 방사선 선종에 따른 후춧가루의 품질변화 차이가 없는 것으로 판단하였으며, 이상의 결과는 X-선의 상업적 이용을 위한 기초 연구 자료로 활용될 수 있을 것으로 사료되었다.