• Journal of Radiation Industry
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• v.2 no.1
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• pp.15-19
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• 2008

In order to develop a water-solubility and biocompatibility, chemically modified chitosan, N,O-carboxymethylchitosan (NOCC), was synthesized and the NOCC hydrogels were prepared by using ${\gamma}-ray$ irradiation instead of chemical reagents. The FT-IR spectroscopy, swelling behavior, gel content and mechanical property such as gel strength of the hydrogel were measured. When the NOCC solution concentration was 15 wt% and the dose of irradiation was less than 50 kGy, the NOCC hydrogels had an excellent hydrophilicity and exhibited a good swelling behavior and mechanical properties.

• Journal of Radiation Industry
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• v.4 no.3
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• pp.289-295
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• 2010

The bacterium Deinococcus radiodurans is one of the most resistant organisms to the effects of ionizing radiation and other DNA-damaging agents. In this study, distributions of 10 ddr (DNA damage response) genes were investigated in 8 species of Deinococcus by polymerase chain reaction (PCR). We have compared the sequences of ddr genes of D. radiodurans, D. geothermalis and D. deserti, and selected primers which are suitable for the detection of ddr in different species of Deinococcus. A sequence homology search and PCR assay showed that ddrO, which encodes a global regulator of the radiation-desiccation response, was most well conserved in the Deinococcus lineage.

• Journal of Radiation Industry
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• v.8 no.2
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• pp.65-69
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• 2014

The cellobiohydrolase gene (cbhI), a key component of a cellulolytic system, of a mutant PfCM4 (Pleurotus florida), developed through gamma ray radiation mutagenesis, was isolated and cloned. The deduced amino acid sequence was closely related to the glycoside hydrolase family 7 (GH7). The molecular weight of the deduced amino acid sequence of cbhI gene was found to be 22.4 kDa. Though the percent identity was found to be much less (35.61%) between the wild type and mutant, the cellulolytic activity of PfCM4 was 17.24% higher than that of the wild type. This shows that the catalytic domain of the cbhI gene was conserved in the mutant PfCM4.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.181-188
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• 2012

A mushroom mutant with increased cellulolytic activity was developed through radiation mutagenesis. The homogenized hypha suspension of Pleurotus florida was exposed to gamma radiation ($^{60}Co$, AECL) at the dose of $LD_{99}$ (0.51 kGy, $D_{10}$; 0.26 kGy). Among 16 mutants, Pf CM4 showed 17.24% more cellulolytic activity than the wild type (p<0.05). It was observed that Pf CM4 can utilize all kinds of carbon sources tested for their mycelia growth. Starch, xylan, and glucose favourably supported the radial mycelia extension. Yeast extract and $NH_4NO_3$ have been recorded as the best organic and inorganic nitrogen sources, respectively. Pf CM4 was found to grow significantly faster, even at high temperature ($30^{\circ}C$), than wild type (p<0.05), and the optimal pH was 5.5~6.5. This study reveals that the mutant Pf CM4 could be employed for the effective recycling of cellulosic wastes, in addition to mushroom farming.

• Journal of Radiation Industry
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• v.2 no.1
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• pp.35-42
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• 2008

The purpose of this study is to observe how the public impression of radiation is changing over the North Korea's nuclear bomb test. We found that the nuclear bomb test brought more negative impressions of radiation, but, in one year, more positive ones prevailed as in the pre-bomb-test. Those positive impressions were found to be composed of useful and positive elements mostly relative to health care. This suggests that we need to apply radiation (fusion) technology to solving everyday life problems in order to bring more positive impressions of radiation.

• Journal of Radiation Industry
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• v.2 no.3
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• pp.129-133
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• 2008

PVA nanofibers containing silver nanoparticles were prepared by two methods. The first method was electrospinning of irradiated solution. The prepared $PVA/AgNO_3$ solution was irradiated by gamma-rays. And then the irradiated solution was electrospun. The second method was irradiation of electrospun nanofibers. Nanofibers prepared by electrospinning of unirradiated $PVA/AgNO_3$ solution. The morphology of the nanofibers was observed with a SEM, TEM. When the irradiated $PVA/AgNO_3$ solution were electrospun, the average size of the Ag nanoparticles was increased, but their number was decreased.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.43-47
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• 2014

By measuring decrease change of the contact angle after microwave plasma treatment on the glass and Al as a scintillator panel sample substrate, the adhesive performance of scintillator panel can be expected to improve. Also resolution and sensitivity of scintillator panel after microwave plasma treatment can be expected to maintain highly.

• Journal of Radiation Industry
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• v.7 no.2_3
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• pp.141-147
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• 2013

The simple and facile radiation technique of the preparation of antibacterial biodegradable polymer films containing silver nanoparticles (Ag NPs) was described. The biodegradable poly(butylene adipate-co-terephthalate) (PBAT) films containing silver trifluoroacetate (Ag TFA) were prepared by a solvent casting method, and then the films were irradiated by electron beams at the various doses ranging from 20 to 200 kGy to form Ag NPs in the biodegradable polymers. The results of UV-vis and FE-SEM/EDX analyses revealed that the Ag NPs were successfully formed in the PBAT matrix during the electron beam irradiation, and their amounts were dependant on the absorbed dose and Ag TFA concentrations. Furthermore, on the basis of the results of the antibacterial test through disk diffusion and colony counting test, the irradiated PBAT/Ag TFA films exhibited the antibacterial property due to the formation of Ag NPs.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.3
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• pp.173-178
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• 2002

In this research, we have worked about the radiation thermometer which can be applied to the hazard circumstance such as steel plant. In the results, we have developed radiation thermometer of a measuring range $500-1500^{\circ}C$, accuracy ${\pm}0.1%$, repeatability ${\pm}0.1%$, resolution $0.2^{\circ}C$. We performed extensive field test for 6 months at the hot strip mill in steel plant. Through the test, we have confirmed the reliability of the developed pyrometer.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.55-59
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• 2012

Polyacrylonitrile (PAN)-based carbon fibers have been widely used due to their unique chemical, electrical, and mechanical properties. Electron beam irradiation has been extensively employed as means of altering properties of polymeric materials. Electron beam irradiation can induce chemical reactions in materials without any catalyst. Electron beam irradiation may be useful in accelerating the thermal compression stabilization of PAN nanofibers. To investigate the irradiation effect on PAN fibers, PAN nanofibers were irradiated by electron beam at 1,000~5,000 kGy. Irradiated and non-irradiated PAN nanofibers were heated at 180 and $220^{\circ}C$ without applying pressure for 15 min. Then 1 metric ton has been applied for 5 min. SEM images have been found that the fiber kept its morphological behavior after the hot pressing up to electron beam irradiated 1,000 kGy. DSC thermograms showed that the peak temperatures of the exothermic reactions were found to decrease with increasing electron beam irradiation doses and temperature. FT-IR spectra have been found to decrease $C{\equiv}N$ stretch band with increasing the electron beam irradiation dose. These results indicate that the modification of PAN via reactions such as cyclization is significantly enhanced by electron beam irradiation and thermal compression technique.