• Journal of the East Asian Society of Dietary Life
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• v.17 no.6
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• pp.816-821
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• 2007

The physical properties and sensory characteristics of acorn starch gels (Dotori Mook), which were gamma-irradiated up to 3 kGy, were evaluated during storage at $4^{\circ}C$. Even at the dose of 2 kGy, the gamma irradiation decreased total bacteria in the Dotori Mook during 5 days of storage, to lower than the detection limit $(10^2CFU/g)$. The hardness of the control sample increased according to the days of storage, while the gamma irradiated samples had decreased hardness according to the irradiation dose. The sample irradiated at 3 kGy maintained the same hardness as the control at day 0 of storage. Irradiation did not affect the Hunter color values. No significant differences were observed in off-odor, color, springiness, and overall acceptability (p<0.05) at the irradiation dose of 2 kGy. It can be concluded that the irradiation of Dotori Mook, up to 2 kGy, does not affect the quality of the Mook during storage, with regard to texture and sensory characteristics. Moreover, the irradiated Mook was superior in maintaining hardness and had prolonged shelf-life time by sanitation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.1121-1124
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• 2015

In this paper, we propose and demonstrate an optimal design of wideband pulsed gamma-ray detectors. Pulsed gamma-ray detectors are designed to operate in a dose rate of $1{\times}10^6{\sim}1{\times}10^8rad(Si)/s$. The input parameter was derived based on the energy ratio of pulse gamma-ray spectrum and the time of the energy. The sensor output current was calculated based on the dose rate control circuit. Using the N-type Epi Wafer, the optimum condition detection sensor was designed based on TCAD. The simulation results show that the optimal Epi layer thickness is 45um when applied voltage 3.3V. The doping concentrations are as follows : N-type is an Arsenic as $1{\times}10^{19}/cm^3$, P-type is a Boron as $1{\times}10^{19}/cm^3$ and Epi layer is Phosphorus as $3.4{\times}10^{12}/cm^3$. Pulse gamma-ray detector diameter is the 1.3mm.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.177-182
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• 2013

This study was conducted to evaluate the effect of gamma irradiation on the microbial populations of dried raw materials (9 products) and Saengsik powder. The samples were gammairradiated at doses of 2, 4, 6 and 8 kGy and the microbiological populations were evaluated. The total numbers of bacteria and Bacillus cereus in non-irradiated dried-raw materials for Saengsik powder was 1.3~3.4 and $1.7{\sim}2.4log\;CFU\;g^{-1}$. However, gamma irradiation reduced the microbiological populations in all samples, and Saengsik powder were sterilized at more than 6 kGy. Moreover, Clostridium perfringens were not observed in all samples within detection limit (<$1log\;CFU\;g^{-1}$). Therefore, the results of this study suggest that gamma irradiation at 6 kGy is sufficient to sterilize Saengsik powder, and thus, irradiated Saengsik powder at 6 kGy fulfills the microbiological requirements for sterilized food.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.93-99
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• 2013

This study was conducted to evaluate the effect of gamma irradiation on the microbiological and sensory characteristics of frozen Bibimbap. Frozen Bibimbap vegetables were contaminated by microbial levels of $2.70{\sim}6.67log\;CFU\;g^{-1}$ in total aerobic bacteria. Frozen Bibimbap was contaminated by microbial levels of $4.8log\;CFU\;g^{-1}$ in total aerobic bacteria, but microorganisms in gamma-irradiated samples at above 25 kGy were not found at detection limit less then $1log\;CFUg^{-1}$. Sensory characteristics of the gamma-irradiated Bibimbap were decreased depending upon the irradiation dose, and sensory scores of the samples irradiated with doses higher than 10 kGy were significantly decreased. Therefore, the application of combination of the various food processing technology should be considered for the sterilization of Bibimbap, without any deterioration of quality occurred by high dose irradiation.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.707-709
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• 2014

The radiation sources leaked from large-scale radiation leak accident like the Fukushima nuclear power plant accident or nuclear explosions can cause to the very large damage for us. So that the damage can be minimized, we have being developed a detector that can providing information about the location of the source to remove dangerous substances quickly than the conventional single detector. In this paper, we designed and implemented the radiation shield and the collimator for the development of the stereo radiation detector to detect contamination things using MCNP Simulation. And we analysed the test results of the radiation shield and collimator using the radiation source. The results of this paper will be used as the basis for improving the efficiency of the stereo radiation detector being studied currently.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.141-147
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• 2010

This study evaluated the antimicrobial effects of retort process and gamma irradiation on reduction of total bacterial populations in spicy chicken sauce, which is served on top of the steamed rice. Commercial spicy chicken sauce was treated with retort and gamma ray at 0, 1, 3, 5, and 10 kGy. Total aerobic bacterial populations were then enumerated on plate count agar and isolated bacteria from the test samples were identified using PCR analysis. Moreover, gamma ray sensitivity of identified bacteria was evaluated by $D_{10}$ values, and genotoxicity of gamma-irradiated samples was examined. Gamma irradiation at 3 kGy reduced total aerobic bacterial cell counts in spicy chicken sauce below detection limit, but total aerobic bacterial cell counts in test samples treated with retort were 2.1 log CFU/g. Identified bacteria from the samples were Bacillus subtilis, B. amyloiquefaciense, and B. pumils, and the $D_{10}$ values for B. subtilis and B. cereus were 0.39 ($R^2\;=\;0.921$) and 0.28 log CFU/g ($R^2\;=\;0.904$), respectively. The SOS chromotest showed that the gamma-irradiated spicy chicken sauce did not cause mutagenicity. These results indicate that gamma irradiation of spicy chicken sauce could be useful in ensuring microbial safety.

• Journal of The Korean Astronomical Society
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• v.37 no.5
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• pp.455-460
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• 2004

There have been many speculations about the presence of cosmic ray protons (CRps) in galaxy clusters over the past two decades. However, no direct evidence such as the characteristic $\gamma$-ray signature of decaying pions has been found so far. These pions would be a direct tracer of hadronic CRp interactions with the ambient thermal gas also yielding observable synchrotron and inverse Compton emission by additionally produced secondary electrons. The obvious question concerns the type of galaxy clusters most likely to yield a signal: Particularly suited sites should be cluster cooling cores due to their high gas and magnetic energy densities. We studied a nearby sample of clusters evincing cooling cores in order to place stringent limits on the cluster CRp population by using non-detections of EGRET. In this context, we examined the possibility of a hadronic origin of Coma-sized radio halos as well as radio mini-halos. Especially for mini-halos, strong clues are provided by the very plausible small amount of required CRp energy density and a matching radio profile. Introducing the hadronic minimum energy criterion, we show that the energetically favored CRp energy density is constrained to $2\%{\pm}1\%$ of the thermal energy density in Perseus. We also studied the CRp population within the cooling core region of Virgo using the TeV $\gamma$-ray detection of M 87 by HEGRA. Both the expected radial $\gamma$-ray profile and the required amount of CRp support this hadronic scenario.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.929-936
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• 2018

A basic characterization of uranium samples was performed using gamma- and X-ray spectroscopy. The studied uranium samples were eight types of certified reference materials with $^{235}U$ enrichments in the range of 1-97%, and the measurements were performed over 24 h using a high-resolution and high-purity planar germanium detector. A general peak analysis of the spectrum and the $XK_{\alpha}$ region of the uranium spectra was carried out by using HyperGam and HyperGam-U, respectively. The standard reference sources were used to calibrate the spectroscopy system. To obtain the absolute detection efficiency, an effective solid angle code, EXVol, was run for each sample. Hence, the peak activities and isotopic activities were determined, and then, the total U content and $^{234}U$, $^{235}U$, and $^{238}U$ isotopic contents were determined and compared with those of the certified reference values. A new method to determine the model age based on the ratio of the activities of $^{223}Ra$ and $^{235}U$ in the sample was studied, and the model age was compared with the known true age. In summary, the present study developed a method for basic characterization of uranium samples by nondestructive gamma-ray spectrometry in 24 h and to obtain information on the sample age.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.262-268
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• 2022

This paper introduces a novel concept of the pulsed neutron facility (PNF) for maximizing the production of the thermal neutrons and its application to medical use based on prompt gamma neutron activation analysis (PGNAA) using Monte Carlo simulations. The PNF consists of a compact D-T neutron generator, a graphite pile, and a detection system using Cadmium telluride (CdTe) detector arrays. The configuration of fuel pins in the graphite monolith and the design and materials for the moderating layer were studied to optimize the thermal neutron yields. Biological samples - normal and cancerous breast tissues - including chlorine, a trace element, were used to investigate the sensitivity of the characteristic γ-rays by neutron-trace material interactions and the detector responses of multiple particles. Around 90 % of neutrons emitted from a deuterium-tritium (D-T) neutron generator thermalized as they passed through the graphite stockpile. The thermal neutrons captured the chlorines in the samples, then the characteristic γ-rays with specific energy levels of 6.12, 7.80 and 8.58 MeV were emitted. Since the concentration of chlorine in the cancerous tissue is twice that in the normal tissue, the count ratio of the characteristic g-rays of the cancerous tissue over the normal tissue is approximately 2.

• Nuclear Engineering and Technology
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• v.53 no.4
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• pp.1277-1283
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• 2021

It is important for operators of poly-pipelines in petroleum industry to continuously monitor characteristics of transferred fluid such as its type and amount. To achieve this aim, in this study a dual energy gamma attenuation technique in combination with artificial neural network (ANN) is proposed to simultaneously determine type and amount of four different petroleum by-products. The detection system is composed of a dual energy gamma source, including americium-241 and barium-133 radioisotopes, and one 2.54 cm × 2.54 cm sodium iodide detector for recording the transmitted photons. Two signals recorded in transmission detector, namely the counts under photo peak of Americium-241 with energy of 59.5 keV and the counts under photo peak of Barium-133 with energy of 356 keV, were applied to the ANN as the two inputs and volume percentages of petroleum by-products were assigned as the outputs.