• Nuclear Engineering and Technology
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• v.55 no.11
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• pp.4077-4082
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• 2023

Large areas must be rapidly screened to monitor radiation in marine environments. For this purpose, this study developed a mobile real-time gamma-ray measurement system for shipboard use and evaluated its performance. The system was developed to measure engine or generator cooling water by installing a canister inside the ship. The minimum detectable activity of the system is about 0.8 Bq/L for a 60 s measurement period, and real-time data transmission and remote control are possible. The system was tested in the field and is currently being installed and operated on ships in service. Such a ship-based real-time gamma-radiation measurement system is suitable for a wide range of marine radiation surveillance applications and is expected to be rapidly deployed.

• Publications of The Korean Astronomical Society
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• v.30 no.2
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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.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.2
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• pp.193-199
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• 2015

We observed that the growth and physiological change in Haliotis discus discus by low-dose irradiation with gamma ray.Irradiation with gamma ray was undertaken by using the low-level irradiation facility ($^{60}CO$) in cooperation with the Institute of Nuclear Science and Technology at Jeju National University. The parent abalones were attached one by one and then fixed by using the rubber band to the front side of the fabricated case for irradiation with gamma ray. The experimental plots of irradiation with gamma ray were set as 10, 15, 20 and 25 Gy and the 25 female abalones and 10 male abalones were utilized for each experimental plot. The sperms and eggs were fertilized by setting an interval for each dose to prevent mixing with other experimental plots when fertilizing the sperms and eggs for each dose of irradiation with gamma ray. As for the fertility, it was confirmed to be 85% the control and 10 Gy groups, whereas it was found to be 80%, 65% and 50% in the 15 Gy, 20 Gy and 25 Gy groups, respectively. As a conclusion, the hatching rate and attachment rate were higher at 10 and 15 Gy than the other experimental plots, and the growth rate was higher at 20 Gy than the other experimental plots. Also the changes in lysozyme activity in accordance with the stress of water temperature were found to have a significant increase in the other experimental plots as compared with the control plot at the end of 0 h. The changes in lysozyme activity have remained constant in all the experimental plots at the end of 12 h. These results allowed us to confirm that lysozyme was undertaking the biodefense action by reacting sensitively to the stress of water temperature in the control experimental plot. As for the other experimental plots, they are believed to avoid the biodefense mechanism due to the high degree of anti-parasite mechanism and anti-viral mechanism. Thus, it is believed that it would be imperative to conduct development and research on breeds that were potent for environmental tolerance by applying the method of irradiation with gamma ray to other marine animals and plants.

• KSBB Journal
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• v.6 no.1
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• pp.45-54
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• 1991

The aims of this study were investigated the antitumor effects and immunological activities of lipopolysaccharides (LPS) extracted from Proteus vulgaris RH-90 toward sarcoma-180 cells. LPS extracted from Proteus vulgris RH-90 was irradiated with gamma ray for detoxification. The tumor incidence of sarcoma-180 occurs all group which injected with gamma ray irradiated LPS and tumor of sarcoma-180 was necrotized with breeding in the injected group of l0$\mu\textrm{g}$ LPS. The inhibition ratio of tumor growth showed at the highest level of 60.88% when 5$\mu\textrm{g}$ gamma ray irradiated LPS was injected into mice. The prolongation ratio of life showed 20.72% when injected into mice with gamma ray irradiated LPS of 5$\mu\textrm{g}$. In the effect of immunological activity, the number of circurating leucocyte and peritoneal exudate cells were increased significantly in the treatment group than that control group, and dose-dependent response indicated by the increase of weights of immunorgans which revealed the improvement of immunity. The effect of macrophage on phagocytes, there were not found the differences between phagocytic and corrected phagocytic index.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.1
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• pp.66.1-66.1
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• 2016

We present our observational results of BL Lacertae(2200+420) obtained at 22, 43, 86, and 129 GHz simultaneously during 27 months(2013.Jan ~ 2015.Mar) which includes their two gamma-ray outbursts(2013.Oct & 2015.Mar) to study a connection between the gamma-ray outbursts and the radio activity. We mainly use a Korean VLBI monitoring program, IMOGABA(Interferometric Monitoring Of Gamma-ray Bright AGNs) which is a monthly monitoring program with the KVN(Korean VLBI Network). Overall, our KVN image shows two components in the map, a stationary core at the center and one moving jet component to the south, but almost core only at 86, 129 GHz. The location of the moving jet component in the maps depend on the frequencies that 22, 43, 86, and 129 GHz. We have checked light curves, spectral index, kinematics, and radio structure to find differences before and after the gamma-ray outbursts, but there was no significant correlation. We also have derived a decay time scale of ~9 months for the major radio outburst by applying an exponential decay fitting.

• Analytical Science and Technology
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• v.35 no.2
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• pp.69-81
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• 2022

The method of measuring and classifying the energy category of neutrons directly using raw data acquired through a CZT detector is not satisfactory, in terms of accuracy and efficiency, because of its poor energy resolution and low measurement efficiency. Moreover, this method of measuring and analyzing the characteristics of low-energy or low-activity gamma-ray sources might be not accurate and efficient in the case of neutrons because of various factors, such as the noise of the CZT detector itself and the influence of environmental radiation. We have therefore developed an efficient method of analyzing radiation characteristics using a neutron and gamma-ray analysis algorithm for the rapid and clear identification of the type, energy, and radioactivity of gamma-ray sources as well as the detection and classification of the energy category (fast or thermal neutrons) of neutron sources, employing raw data acquired through a CZT detector. The neutron analysis algorithm is based on the fact that in the energy-spectrum channel of 558.6 keV emitted in the nuclear reaction ¹¹³Cd + ¹n → ¹¹⁴Cd + in the CZT detector, there is a notable difference in detection information between a CZT detector without a PE modulator and a CZT detector with a PE modulator, but there is no significant difference between the two detectors in other energy-spectrum channels. In addition, the gamma-ray analysis algorithm uses the difference in the detection information of the CZT detector between the unique characteristic energy-spectrum channel of a gamma-ray source and other channels. This efficient method of analyzing radiation characteristics is expected to be useful for the rapid radiation detection and accurate information collection on radiation sources, which are required to minimize radiation damage and manage accidents in national disaster situations, such as large-scale radioactivity leak accidents at nuclear power plants or nuclear material handling facilities.

• International Journal of Oral Biology
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• v.34 no.1
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• pp.15-20
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• 2009

In our present study, total methanol extracts prepared from B. platyphylla var. japonica showed a significant increase in cell proliferation upon the induction of oxidative stress by hydrogen peroxide or $\gamma$-ray irradiation. Total methanol extracts were fractionated into five separate preparations i.e. n-hexane, dichloromethane, ethylacetate, n-butanol and water fractions. Among these, the ethylacetate and butanol fractions of B. platyphylla var. japonica showed the highest protective effects against oxidative stress induced by hydrogen peroxide. These fractions also showed strong protective effects against $\gamma$-ray irradiation. When we evaluated the cytotoxicity of these fractions, the butanol fraction showed no effects in a colony formation assay. In addition, the butanol fraction showed a cell proliferation activation effect evidenced by significant increase in the colony formation of $\gamma$-ray irradiated cells. Both a radical scavenging activity and clonogenic activity assay suggested that the mechanism behind this protective effect against reactive oxygen species may be due to the radical scavenging and cell proliferation activity of B. platyphylla var. japonica extracts.

• Journal of Sensor Science and Technology
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• v.24 no.3
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• pp.202-207
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• 2015

As a feasibility study on development of a gamma imaging probe, we developed a scintillating film-based gamma imaging detector that can obtain scintillation images with information of gamma-ray distribution. The scintillating film-based gamma imaging detector was composed of a sensing probe, an image intensifier, and a beam profiler. To detect and transmit scintillation image, the sensing probe was fabricated by coupling a scintillating film, a fiber-optic image conduit, and a fiber-optic taper, consecutively. First, the optical images of USAF 1951 resolution target were obtained and then, modulation transfer function values were calculated to test the image quality of the sensing probe. Second, we measured the scintillation images according to the activity of the 137Cs and the distance between the surface of 137Cs and the distal-end of sensing probe. Finally, the intensities of scintillating light as functions of the activity and the distance were evaluated from the region of interest in the scintillation image. From the results of this study, it is expected that a fiber-optic gamma imaging detector can be developed to detect gamma-rays emitted from radiopharmaceuticals during radioimmunoguided surgery.

• Applied Biological Chemistry
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• v.51 no.2
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• pp.148-152
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• 2008

This study was to elucidate the effect of low dose gamma (${\gamma}$)-ray irradiation on the germination, seedling growth and antioxidant activity in sunflower seeds. The seed germination was stimulated in the range of 2.7${\sim}$8.0% by low dose ${\gamma}$-ray irradiation compared with that of the control; however, the germination of seeds stored for 4 months after irradiated was decreased at all low dose ${\gamma}$-ray irradiation groups. Especially, the germination rate of 32 Gy-irradiated seed group was much lower than that of the other groups and 8 Gy was the optimal radiation dose for germination at room temperature. Though there was variation with storage time and temperature, seedling growth stored at 10$^{\circ}C$ for 4 months after irradiated was promoted at the 1 Gy ${\gamma}$-ray irradiation group compared to seed stored at 25$^{\circ}C$. For the antioxidant activity of ${\gamma}$-ray irradiated seeds extract, 4 Gy and 32 Gy groups were significantly increased by 68.83% and 95.44%, respectively, compared to control at the concentration of 100 ${\mu}g$/ml.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.165-168
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• 2011

The antioxidant activity was analyzed in gamma-irradiated cooking juices. Because the activities of antioxidants have been attributed to various mechanisms, different assay methods including 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP), have been conducted and compared. All of these antioxidant assay showed that the antioxidant activity of cooking juice was increased by gamma-irradiation. To investigate this increase of antioxidative activity, the protein was extracted from cooking juices and its antioxidant activity was measured. From the results, it was thought that the modification of protein in cooking juiced by irradiation caused the increase of antioxidant activity of cooking juice. Therefore, gamma irradiation could be an promising method for a sterilization of cooking juice with increased antioxidant activity.