• 상하수도학회지
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• 제26권3호
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• pp.373-381
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• 2012

Antibiotics have been issued recently in water environments because of potential impacts on ecosystem and public health. This study was aimed to investigating the degradation of antibiotics such as tetracycline, lincomycin, sulfamethazine and cephradine using gamma ray irradiation. And the toxicity before and after irradiation on antibiotics was tested in order to examine the aquatic eco-risk assessment by aquatic organisms. In addition, comparing tests on toxicity for gamma ray and UV irradiated antibiotics was conducted. Four different antibiotics were prepared by concentration of 30 mg/L with demi-water respectively. The absorption dose of gamma ray was ranged from 0.2 to 2 kGy. The concentration of four antibiotics was gradually decreased corresponding to the increase of the absorption dose. A method for toxicity assessment using Pseudokirchneriella subcapitata was evaluated to the most acceptable compared with methods by Daphnia magna and Microtox$^{(R)}$ in terms of sensibility. It showed that the reduction of toxicity on antibiotics treated by gamma ray was superior comparing to the test results obtained from UV treatment. By-products from antibiotics treated by gamma ray were easily decomposed by microorganism and their toxicity was also evaluated to low.

• 한국잠사곤충학회지
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• 제10권
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• pp.63-66
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• 1969

As a result of analyzing the change of material substance of all sorts biochemically and comparing the control with ${\gamma}$-ray irradiation (800r, 400 min), incubating the silkworm egges (bombyx. mori. L.) as the objective in the process of growth of embryo shortly before hatching, the following conclusion has been found. 1. Glucose has shown the increase of 281.2 mg/g in control during the pigment stage and it has shown the increase of 179.6 mg/g in ${\gamma}$-ray irradiation during the same period. The difference in quantity between the former and the latter is due to the fact that the growth of embryo has been influenced by the radio active. Glucose has changed with phosphorus the other way round. 2. Control organic phosphorus has shown the increase of 5.23 mg/g during the Byong B or KI A in which organ and tissue in the embryo has been formed. Organic phosphorus in ${\gamma}$-ray irradiation has shown the increase of 5.73 mg/g during KI B. Inorganic Phosphorus has shown only a little change in the control and ${\gamma}$-ray irradiation. The phosphorus in both has shown a little quantity in the ${\gamma}$-ray irradiation in early period of incubation. After the Ki A embryo, it has increased rapidly and it has increased till the hatching more continually than in control. The about results of the research will be helpful and instructive to the betterment and improvement, breeding and management of animals and plants.

• 연구논문집
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• 통권32호
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• pp.65-76
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• 2002

The intensity of x-ray or gamma-ray is attenuated according to density and thickness of the transmitted medium. In this study, by using this principle, on-line real-time radiometric system was developed using a 128 channels linear array of solid state detectors to measure wall thickness of insulated piping system. This system uses a Ir-192 as a gamma ray source and detector is composed of BGO scintillator and photodiode. Ir-192 gamma ray source and linear detector array mounted on a computer controlled robotic crawler. The Ir-192 gamma ray source is located on one side of the piping components and the detector array on the other side. The individual detectors of the detector array measure the intensity of the gamma rays after passing through the walls and the insulation of the piping component under measurement. The output of the detector array is amplified by amplifier and transmitted to the computer. This system collects and analyses the data from the detector array in real-time. The maximum measurable length of pipe is 120cm/mm. in the case of 1mm scanning interval.

• 한국축산식품학회지
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• 제18권3호
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• pp.232-239
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• 1998

This experiment was conducted to investigate radurization effects of gamma ray and electron beam irradiation at 1.5 and 3.0 kGy on beef steaks during 8 days of storage at 5$^{\circ}C$. Total bacteria count, psychrotrophs, mesophiles and thermophiles were analyzed at 2 days intervals. Nonirradiated beef steak was used a scontrol Total bacteria counts, psychrotrophs, mesophiles and thermophiles of the control samples showed 3.03∼4.72 logCFU / g at 0 day and increased to 7.67∼10.90 logCFU / g during 8 days storage except thermophiles. Total bacteria counts, psychrotrophs and mesophiles of beef steaks at 8 days were significantly (p＜0.05) decreased to 3.61∼5.43 logCFU / g by gamma ray and to 3.83∼7.02 logCFU / g by electron beam irradiation at 1.5 and 3.0 kGy. Thermophiles of all irradiated samples at any dose were not detectable through 8 days storage. These results suggested that both gamma ray and electron beam irradiation were effective to extend lag phase of bacterial growth of refrigerated beef. Gamma ray irradiation was better than electron beam irradiation in terms of radurization effects of beef.

• 천문학논총
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• 제30권2호
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• pp.429-432
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• 2015

We present a kinematic study of the parsec-scale radio jet in OJ 287, one of the most studied BL Lac objects, during ${\gamma}$-ray flares, to explore the relation between parsec-scale radio jet activity and ${\gamma}$-ray emission. The 22-GHz light curve of OJ 287 show three obvious flare events around 2011 May, 2011 October, and 2012 March. The second radio flare occurred during the ${\gamma}$-ray flaring period, and the third radio flare seemed to precede the ${\gamma}$-ray flare by one month. One jet component moved outward with respect to the core component with an apparent superluminal speed (~ 11c) from 2010 November to 2011 November. Then it changed direction, moving apparently inward in 2011 November, when the ${\gamma}$-ray flare occurred. The observed apparent inward motion of the jet at 22 GHz could be caused by a new jet component, unresolved at 22 GHz, in the innermost region.

• 방사선산업학회지
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• 제6권1호
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• pp.17-21
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• 2012

The effects of gamma ray or electron beam irradiation on herbaceous medicinal plants were investigated in terms of the composition of volatile constituents using the aerial parts or leaves of Artemisia princeps Pamp. cv. Ganghwayakssuk and Artemisia argyi cvs. Namhaeyakssuk and Hwanghaessuk. The composition of volatile constituents in leaves was clearly distinguishable among the three Artemisia cultivars. However, the relative proportions of the major volatile constituents such as 1,8-cineole, ${\alpha}$-pinene, camphene, santolina triene, and artemesia triene, were similarly changed in two or three cultivars by gamma ray or electron beam irradiation. In particular, the proportion of 1,8-cineole was increased up to 1.29- to 1.71-fold in the three cultivars after irradiation with gamma ray. These results suggest that gamma ray or electron beam irradiation can be applied to modulate the composition of volatile constituents in the leaves of Artemisia plants.

• 방사선산업학회지
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• 제6권3호
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• pp.231-237
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• 2012

This paper introduces a gamma-ray measurement system for a transportable tomography which is applicable for an industrial process diagnosis. The gamma-ray measurement system consists of pulse mode operating 72 channel CsI detectors, main AMP-pulse shaper, single channel analyzer, counter and control PC. The CsI crystal is coupled with a PIN diode which is connected to an amplifier and pulse shaper. For a compact design, the amplifier and pulse shaping circuit are included in a single package. 36 sets of CsI detectors are connected to a multi-channel counter through single channel analyzers. A computer controls and collects data from two multi-channel counters. This configuration results in 72 channel counting system in total. The CT rotator and radiation measurement system are controlled by a PC with LabVIEW program. Tomographic data were measured for a phantom by the measurement system and transportable gamma-ray CT. From the experimental data image reconstructions were performed by ML-EM algorithm. The result showed that the CsI detector system can be a suitable component for transportable gamma-ray CT system.

• Nuclear Engineering and Technology
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• 제55권9호
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• pp.3401-3408
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• 2023

In this study, we used the Monte Carlo N-Particle program to simulate the gamma-ray spectra obtained from plastic scintillators holes filled with bismuth nanoparticles. We confirmed that the incorporation of bismuth nanoparticles into a plastic scintillator enhances its performance for gamma-ray spectroscopy using the subtraction method. The subtracted energy spectra obtained from the bismuth-nanoparticle-incorporated and the original plastic scintillator exhibit a distinct energy peak that does not appear in the corresponding original spectra. We varied the diameter and depth of the bismuth-filled holes to determine the optimal hole design for gamma-ray spectroscopy using the subtraction method. We evaluated the energy resolutions of the energy peaks in the gamma-ray spectra to estimate the effects of the bismuth nanoparticles and determine their optimum volume in the plastic scintillator. In addition, we calculated the peak-to-total ratio of the energy spectrum to evaluate the energy measuring limit of the bismuth nanoparticle-containing plastic scintillator using the subtraction method.

• Nuclear Engineering and Technology
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• 제54권12호
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• pp.4684-4692
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• 2022

Radionuclide identification is an important part of the nuclear material identification system. The development of artificial intelligence and machine learning has made nuclide identification rapid and automatic. However, many methods directly use existing deep learning models to analyze the gamma-ray spectrum, which lacks interpretability for researchers. This study proposes an explainable radionuclide identification algorithm based on the convolutional neural network and class activation mapping. This method shows the area of interest of the neural network on the gamma-ray spectrum by generating a class activation map. We analyzed the class activation map of the gamma-ray spectrum of different types, different gross counts, and different signal-to-noise ratios. The results show that the convolutional neural network attempted to learn the relationship between the input gamma-ray spectrum and the nuclide type, and could identify the nuclide based on the photoelectric peak and Compton edge. Furthermore, the results explain why the neural network could identify gamma-ray spectra with low counts and low signal-to-noise ratios. Thus, the findings improve researchers' confidence in the ability of neural networks to identify nuclides and promote the application of artificial intelligence methods in the field of nuclide identification.

• Nuclear Engineering and Technology
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• 제7권2호
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• pp.85-94
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• 1975

n형 Ge 결정체를 보상하기 위해 상온에서 $^{60}$Co 감마선으로 647 Mrad 조사하였다. 감마선으로 조사된 Ge 결정체로 Ge(${\gamma}$) 검출기를 제작하였다. Ge(${\gamma}$) 검출기의 검출기 특성은 얇은 Ge(Li) 검출기나 고순도 Ge 검출기와 비슷하였다. Ge(${\gamma}$) 검출기의 온도에 대한 안정도는 상온에서의 저장이 가능함을 보여 주었다.