• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.152-153
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• 2009

• Analytical Science and Technology
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• v.16 no.1
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• pp.12-24
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• 2003

For the design and set-up of neutron induced prompt ${\gamma}$-ray spectroscopy system using $^{252}Cf$ neutron source, the effects of shielding and moderator materials have been examined. The $^{252}Cf$ source being used for TLD badge calibration in Korea Atomic Energy Research Institute was utilized for this preliminary experiment. The ${\gamma}$-ray background and prompt ${\gamma}$-ray spectrum of the sample containing Cl were measured using HPGe (GMX 60% relative efficiency) located at the inside of the system connected to notebook PC at the outside of the system (about 20 meter distance). The background activities of neutron and ${\gamma}$-rays were measured with neutron survey meter as well as ${\gamma}$-ray survey meters, respectively and the system was designed to minimize the activities. Prompt ${\gamma}$-ray spectrum was measured using ${\gamma}$-${\gamma}$ coincident system for reduce the background and the continuum spectrum. The optimum system was designed and set up using the experimental data obtained.

• Journal of the Korean Society of Radiology
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• v.13 no.5
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• pp.819-824
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• 2019

In this study, we proposed a method for identifying isotopes generated from high-energy proton $^{nat}Pb$(p,xn) nuclear reactions through the difference of gamma rays generated through nuclear reactions using different proton energies. The experiment was performed by using a high energy proton generated from a 100 MeV proton linear accelerator of the Korea Atomic Energy Research Institute. Gamma rays generated by various nuclides generated through proton nuclear reactions were measured using a gamma-ray spectroscopy system composed of HPGe detectors. Gamma-ray standard sources were used for accurate energy calibration and efficiency measurements of HPGe gamma-ray detectors. For the proposed method, 100 and 60 MeV proton energy beams were used for the same natural lead samples. This method was found to be very effective in identifying nuclides produced by comparing gamma rays generated from the same sample with each other. The results of this study are expected to be very effective in obtaining other proton nuclear reaction results in the future.

• Journal of Radiation Protection and Research
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• v.3 no.1
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• pp.29-32
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• 1978

A shielding calculation has been carried out for a storage vault of $5292(42{\times}42{\times}3)$ waste drums in which the mixed radioactive gamma-emitters are contained. The required ordinary concrete shielding thickness seems to be approximately 50cm. The results in terms of dose rate for polyenergy gammas appear to be considerably higher than those of the averaged energy gamma.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1100-1102
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• 2015

In the study, stereo-based of gamma-ray sources detector for the space including the gamma-ray source to scan in a raster scan method, and obtains a visible light image and the gamma-ray image. We went to retrieve and visualize the distance to source and the direction of the 3-dimension information from Stereo gamma-ray detectors. Configuration of the detector consisted of gamma-ray detecting sensor for gamma-ray Sources, pan-tilt for the scanning of the raster for detecting sources, and CCD camera for visible-light image. Implement a stereo structure of the device to measure the spatial distribution of source, the gamma-ray Detector and CCD camera for the stereo image acquisition was as each configuration 2. The gamma-ray detector and a visible light camera to revision the distribution of detection source, After performing each of the cameras of the stereo correction and shows the distribution of the gamma-ray Sources through 중첩 visible light image and the gamma-ray image. After Rectification process of Left and right image, we were derived visualization results of the stereo image.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.282-284
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• 2005

본 연구는 특수목적식품을 개발하기 위한 대표적인 비가열 살균처리 기술인 방사선 살균기술을 이용하여 저장 중 프레스햄의 미생물학적 품질을 평가하고자 하였다. 그 결과 감마선비조사구의 경우 제조공정 단계에 관계없이 $30^{\circ}C$ 저장 4일 째에 모두 미생물 생육이 활발해져 장기저장에 부적합한 것으로 나타났으나, 감마선을 조사할 경우 훈연후 및 살균전 시료의 경우 5 kGy, 살균후 시료의 경우 3 kGy의 감마선 조사로 $30^{\circ}C$ 저장 4일 까지 미생물의 생육이 검출되지 않았다. 따라서, 감마선 조사기술은 프레스햄의 살균방법으로 이용이 가능하며, 특히 장기저장을 목적으로 하는 우주식, 환자식, 전투식량 등의 특수목적식품의 개발에 그 이용이 가능하다 할 수 있다.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.431-435
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• 2016

The aim of this study was to investigate the effect of gamma irradiation on the pretreatment of wood chips with NaOH solution. The degree of saccharification was quantified by measuring reducing sugar and glucose concentrations after enzymatic hydrolysis. After pretreatment with 10 g/L NaOH, the wood chips were irradiated at the doses of 0, 50, 100, and 200 kGy, respectively. Among the irradiated samples, wood chips irradiated at the dose of 200 kGy had the highest reducing sugar concentration of 12.2 g/L. Also, to define the effect of irradiation before pretreatment, the wood chips were first gamma-irradiated and then pretreated with NaOH. When the NaOH treatment was conducted after irradiation at 200 kGy, the reducing sugar content was further increased to 13.4 g/L and glucose content of the wood chip was as high as 7.9 g/L. These results suggest that gamma irradiation may be the promising method for pretreatment of cellulose biomass.

• Food Science and Preservation
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• v.8 no.1
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• pp.16-22
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• 2001

The study was performed to investigate the effects of delayed gamma-irradiation and CA storage on the keeping quality of chestnuts. Chestnuts peviously stored for 3 months at 0$^{\circ}C$ were irradiated at 0 to 0.25 kGy of Co$\^$60/ gamma rays and then stored for 6 months under CA conditions of 3% O$_2$ and 5% CO$_2$ or air at 0$^{\circ}C$. Delayed gamma-irradiation completely inhibited the sprouting of chestnuts, and tore reduced the rotting rate by the combination with CA storage. The weight loss was reduced by delayed gamma-irradiation and CA storage. Hunter L and b values of flesh surface of the chestnuts stored under CA were higher than those of samples stored under air regardless of gamma irradiation. Vitamin C, total sugar and reducing sugar contents decreased immediately after irradiation Vitamin C and reducing sugar contents after 6 months of storage were lower in the samples kept under CA than in those under air. Results indicated that delayed gamma-irradiation after harvest and subsequent CA storage showed inhibitory effects against the development of saluting and rotting and the loss of weights and surface flesh color changes in chestnuts.

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.249-253
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• 2004

CdS semiconductor quantum dot (QD) structures in aqueous solution are fabricated by using a gamma-ray irradiation technique and their optical absorption spectra are investigated. Cadmium sulfate solution, 2-mercaptoethanol solution, and reducing agent $e^{-}_{aq}$ are employed to produce CdS molecules, leading to CdS quantum dots. The measured linear absorption spectra before and after g-ray irradiation clearly show exciton peaks between 300 nm and 400 nm, which indicate the formation of CdS QD's. It is also observed that the exciton peaks are red-shifted with increasing the g-ray irradiation time from 5 min to 15 min. Therefore, it is concluded that the mean QD sizes can be systematically controlled with the dosage of the g-ray irradiation.

• Food Science and Preservation
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• v.15 no.3
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• pp.377-384
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• 2008

The gamma irradiation process was performed to prolong a shelf-life of peaches and the effects of a gamma irradiation on the nutritional, physiochemical and sensory characteristics of peaches were evaluated during a post-irradiation storage at $4^{\circ}C$ and $25^{\circ}C$. Nutritional, physiochemical and sensory characteristics of peaches were stable at 1 kGy of an irradiation, a recommended dose for fruits and vegetables by CODEX, and the viable cell counts of contaminated microorganisms were reduced by 2 decimal reduction, at this dose. After a 1-week storage at ambient condition, the microbiological quality of the 1 kGy irradiated peach was stable, while all the non-irradiated peaches were deteriorated Furthermore, cold storage enhanced the shelf-life of the gamma irradiated peach and the nutritional and physiochemical characteristics of the peaches were comparatively stable up to 6 weeks. Right after gamma irradiation, the sensory evaluation results were not different in any of the samples, and the sensory quality of the irradiated peaches was adequate for a 4-week storage at $4^{\circ}C$. Our results suggested that gamma irradiation at 1 kGy can be used to enhance the shelf-life of peach without a significant loss in the quality attributes, especially upon cold storage after radiation treatment.