• 동의생리병리학회지
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• 제20권3호
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• pp.670-674
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• 2006

This experimental study was carried out to investigate the immunostimulating effect of Acanthopanax, as Oriental rhizomata herbs, on jejunal survival, endogenous spleen colony formation, apoptosis in jejunal crypt cells and lipid peroxidation in the liver of mice following Gamma-ray irradiation. The subject of this study includes 72 mice which were divided into each 7 groups. Acanthopanax experiment groups were Acanthopanax. Gamma-ray(lOGy), Acanthopanax. Gamma-ray(3Gy), Acanthopnax. Gamma-ray(1Gy), Gamma-ray control(1OGy), Gamma-ray control(3Gy), Gamma-ray control(1Gy), Normal groups. The results of this study were as follows : Treatment with Acanthopanax showed significantly increased(p<0.05) on the cell death apoptosis in crypt, intestine crypts survival of intestine in mice following low-dose(1Gy) Gamma-ray radiation. And that significantly increased(p<0.05) on jejunal crypt survival and reduced(p<0.05) on lipid peroxidation in mice following high-dose(1OGy) Gamma-ray radiation. The above results suggest that Acathopanax were immunostimulating effectively reduced Gamma-ray irradiation.

• 방사선산업학회지
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• 제7권1호
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• pp.51-54
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• 2013

Chitosan is a useful natural polymer material in many application fields such as biomaterials, water-treatment, agriculture, medication, and food science. However, the poor solubility limits its application. In this study, the effects of radiation on chitosan were investigated using gamma ray and electron beam irradiation. The chemical structure and molecular weight analysis show similar degradation effects of chitosan powder in both gamma ray and electron beam irradiation. However, the radiation irradiated chitosan in $H_2O$ has a lower molecular weight, since the hydroxyl radicals attack the glycosidic bonds. This effect is more clearly shown in the electron beam irradiation results.

• Journal of Radiation Protection and Research
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• 제43권4호
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• pp.137-142
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• 2018

Background: Gamma-ray detectors having a thin window of a material with low atomic number can increase the true coincidence summing effects for radionuclides emitting X-rays or gamma-rays. This effect can make efficiency calibration or spectrum analysis more complicated. In this study, a Cu shield was tested as an X-ray filter to neglect the true coincidence summing effect by X-rays and gamma-rays in gamma-ray spectrometry, in order to simplify gamma-ray energy spectrum analysis. Materials and Methods: A Cu shield was designed and applied to an n-type high-purity germanium detector having an $X-{\gamma}$ summing effect during efficiency calibration. This was tested using a commercial, certified mixed gamma-ray source. The feasibility of a Cu shield was evaluated by comparing efficiency calibration results with and without the shield. Results and Discussion: In this study, the thickness of a Cu shield needed to avoid true coincidence summing effects due to $X-{\gamma}$ was tested and determined to be 1 mm, considering the detection efficiency desired for higher energy. As a result, the accuracy of the detection efficiency calibration was improved by more than 13% by reducing $X-{\gamma}$ summing. Conclusion: The $X-{\gamma}$ summing effect should be considered, along with ${\gamma}-{\gamma}$ summing, when a detection efficiency calibration is implemented and appropriate shielding material can be useful for simplifying analysis of the gamma-ray energy spectra.

• 방사선산업학회지
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• 제6권3호
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• pp.251-255
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• 2012

Pulp is typically used for paper industry to manufacturing various types of papers. However simply chemical modification makes enable the pulp to a wide range of application in various industrial fields. To bring the polymerization the gamma ray irradiated on the mixture of kenaf and PEGMA in various dose ranges from 20 to 60 kGy. As a results, the graft degree of 20.0% was obtained from 475 g of gamma ray irradiated pulp and PEGMA. After the polymerization, the chemical structure and morphology of the surfaces were examined by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscope. Chemical structure of grafted pulp has significantly growth in carbonyl content with increasing the radiation dose. Also surface morphology was distinctly changed with decreased the degree of roughness and increasing the diameter. These results were explained gamma ray irradiation improve performance of graft polymerization efficiency.

• 방사선산업학회지
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• 제8권1호
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• pp.49-52
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• 2014

Kenaf fibers have excellent properties and possess the potential to be outstanding reinforcing fillers in cement. The grafting of poly(ethylene glycol) methacrylate (PEGMA) to the kenaf fibers is important in improving the compatibility between the fibers and the cement. PEGMA was grafted onto kenaf fibers using gamma-ray radiation. The radiation dose ranged from 20 to 60 kGy, and the dose rate was $10kGy\;h^{-1}$. The degree of grafting increased with increased radiation doses. FT-IR analysis revealed an increase in PEGMA content after gamma-ray radiation induced grafting, further evincing the attachment of PEGMA to the kenaf fibers. The mechanical properties of the gamma-ray grafted kenaf fiber/cement composites were superior to those of the ungrafted kenaf fiber/cement specimens.

• Macromolecular Research
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• 제10권6호
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• pp.332-338
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• 2002

The effect of an electron beam and ${\gamma}$-ray irradiation on the curing of epoxy resins was investigated. Diglycidyl ether of bisphenol A (DGEBA) and diglycidyl ether of bisphenol F (DGEBF) as epoxy resin were used. The epoxy resins containing 1.0-3.() wt% of triarylsulphonium hexafluoroantimonate(TASHFA) and triarylsulphonium hexafluorophosphate(TASHFP) as initiator were irradiated under nitrogen at room temperature with different dosage of EB and ${\gamma}$-rays from a Co$^{60}$ u source. The chemical and mechanical characteristics of irradiated epoxy resins were compared after curing of EB and ${\gamma}$-ray irradiation. The thermal properties of cured epoxy were investigated using dynamic mechanical thermal analysis. The chemical structures of cured epoxy were characterized using near infrared spectroscopy. Mechanical properties such as flexural strength, modulus were measured. The gel fraction of DGEBA with ${\gamma}$-ray was higher than that of the epoxy with EB at the same dose. Young's modulus of the sample irradiated by ${\gamma}$-ray is higher than that of sample cured by EB. From the result of strain at yield, it was found that the epoxy cured by ${\gamma}$-ray had a higher stiff property compared with the irradiated by EB.

• 펄프종이기술
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• 제42권3호
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• pp.43-49
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• 2010

Recently, the use of fumigants for pest control of paper cultural heritages are limited because of the high toxicity of fumigants and the production of environment-harmfully compounds. Therefore, many non-chemical methods have been discussed and experimented. And it is recently focused on gamma radiation, which is one of non-chemical methods, for pest control of paper cultural heritage in Korea. In this paper, we carried out a gamma ray irradiation of papers including Hanji, copy paper, filter paper and then analyzed a physical properties and optical properties of paper sample to estimate the effect of gamma ray irradiation on paper properties. In result, gamma radiation have adverse effect on a physical properties and optical properties of paper, especially Hanji. Therefore, we have to carefully consider about using of gamma ray for pest control of paper cultural heritages.

• 전기학회논문지
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• 제59권9호
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• pp.1611-1614
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• 2010

The explosion of a nuclear weapon radiates a gamma-ray in the form of a transient pulse. If the gamma-ray introduces to semiconductor devices, much Electron-Hole Pairs(EHPs) are generated in depletion region of the devices[7]. as a consequence of that, high photocurrent is created and causes upset, latchup and burnout of semiconductor devices[8]. This phenomenon is known for Transient Radiation Effects on Electronics(TREE), also called dose-rate effects. In this paper 3D structure of inverter and NAND gate device was designed and transient pulse gamma-ray was modeled. So simulation for transient radiation effect on inverter and NAND gate was accomplished and mechanism for upset and latchup was analyzed.

• Journal of Ceramic Processing Research
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• 제20권4호
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• pp.363-371
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• 2019

In this study, physical properties of normal concrete, magnetite concrete, EAF concrete, and EAF concrete with added iron powder were evaluated and a feasibility of radiation shielding is also evaluated through irradiation tests against X-rays and gamma-rays. While the unit weight of EAF concrete (3.21 t/㎥) appeared lower than that of magnetite concrete (3.50 t/㎥), the results in compressive strength of EAF concrete were greater than those in magnetite and normal concrete. While the radiation transmission rate of normal concrete reaches 26.0% in the X-ray irradiation test, only 6.0% and 9.0% of transmission rate were observed in magnetite concrete and linear relationship with unit volume weight and radiation shielding. In the gamma-ray irradiation test, the performance of EAF and magnetite concretes appeared to be similar. Through the results on the excellent physical properties and radiation shielding performance a potential applicability of EAF concrete to radiation shielding was verified.

• 방사선산업학회지
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• 제6권1호
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• pp.23-29
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• 2012

In this study, we investigated the genetic variation in the general of monocot model plant (rice) in response to various ionizing irradiations including gamma-ray, ion beam and cosmic-ray. The non-irradiated and three irradiated (200 Gy of gamma-ray and 40 Gy of ion beam and cosmic-ray) plants were analyzed by AFLP technique using capillary electrophoresis with ABI3130xl genetic analyzer. The 29 primer combinations tested produced polymorphism results showing a total of 2,238 bands with fragments sizes ranged from 30 bp to 600 bp. The number of polymorphism generated by each primer combinations was varied significantly, ranging from 2 (M-CAC/E-ACG) to 158 (M-CAT/E-AGG) with an average of 77 bands. Polymorphic peaks were detected as 1,269 with an average of 44 per primer combinations. By UPGMA (Unweighted Pair Group Method using Arithmetic clustering) analysis method, the clusters were divided into non-irradiated sample and three irradiated samples at a similarity coefficient of 0.41 and three irradiation samples was subdivided into cosmic-ray and two irradiation samples (200 Gy of gamma-ray and 40 Gy of ion beam) at similarity coefficient of 0.48. Similarity coefficient values ranged from 0.41 to 0.55.