• Journal of Radiation Industry
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• v.5 no.1
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• pp.41-46
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• 2011

Polyacrylonitrile (PAN) fibers are the most widely used precursor of the materials for carbon fibers. The conventional process of carbon fibers from PAN precursor fiber includes two step; stabilization at low temperature and carbonization at high temperature. Compared to thermal stabilization, the stabilization process by electron beam (E-beam) irradiation is a advanced and brief method. However, a stabilization by E-beam irradiation was required a high dose (over 5,000 kGy) and spend over 1.5 hr (1.14 MeV, 1 mA). In the present work the main goal is exploring a quick stabilization process by cotrolling E-beam currents. The effect of various E-beam currents on stabilization of PAN precursor fiber was studied by gel fraction test, thermo gravimertic analysis (TGA), differential scanning calorimetry (DSC), tensile strength, and scanning electron microscopy (SEM) images.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.179-184
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• 2011

In this study, several anion exchange membranes were successfully prepared by radiation grafting of vinylbenzyl chloride (VBC) monomer onto a polyethylene-co-tetrafluoroethylene (ETFE) film and subsequent quaternarization with diamins such as 1,4-diazbicyclo[2,2,2]octane, N,N,N',N'-tetramethyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,6-diaminohexane, and trimethylamine. The anion exchange capacities of the prepared membranes were determined by using acid-base titration method. The cross-sectional morphology of the membranes was studied by using SEM instrument. The cross-sectional distribution patterns of the grafted polymers with anion exchange functional groups were also studied by EDX analysis.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.113-118
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• 2011

Hydrogels from a mixture of poly(N-vinylpyrrolidone) (PVP), ${\kappa}$-carrageenan and microorganism fermentation celluose were prepared by $^{60}Co$ gamma-ray irradiation. PVP and ${\kappa}$-carrageenan were mixed with the different ratios. Microorganism fermentation celluose were added to the mixture of PVP and ${\kappa}$-carrageenan to evaluate the effect of microorganism fermentation celluose on the gel strength. The gel strength of the hydrogel was evaluated for application of a wound dressing. The results showed that gelation and gel strength were increased with increasing the content of the microorganism fermentation celluose.

• Journal of Radiation Industry
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• v.5 no.3
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• pp.227-230
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• 2011

Pulps were separated from wood chips using an Electron beam irradiation (EBI) treatment without a NaOH-AQ (anthraquinone) treatment for cooking. The methods were based on a hot water treatment after EBI and two-step bleaching processes. Chemical compositions and FT-IR spectroscopy demonstrated that the content of lignin and hemicellulose in the bleached wood pulps treated with various EBI dose decreased with an increase of EBI doses. Specifically, the lignin in the bleached with pulps treated at 600 kGy of EBI dose was almost completely removed. Moreover, TGA analysis showed that a thermal stability increased with increasing the content of cellulose but the lignin decomposed slowly over the wide region.

• Journal of Radiation Industry
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• v.7 no.1
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• pp.55-59
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• 2013

Ionizing radiation causes the massive generation of reactive oxygen species, resulting in cellular and tissue damage. The present study was performed to evaluate ${\gamma}$-irradiation induced cellular damage in ICR mice. The mice were divided into four groups with ten mice in each group. Group 1 served as an unexposed control group. Groups 2, 3, and 4 were exposed to 3, 5, and 7 Gy of ${\gamma}$-radiation, respectively. Five mice per group were sacrificed 1 and 7 days after ${\gamma}$-radiation. Exposure to ${\gamma}$-irradiation resulted in hematopoietic damage in a dose-dependent manner when compared with the unexposed control group, which featured a significantly decreased spleen index. However, the exposed mice showed no significant differences in their serum AST, ALT and in the histopathological change of their liver. These results suggest that ${\gamma}$-irradiation is a good tool to prepare a hematopoietic damage model. This animal model can be employed to study the hematopoietic efficacy of biologically active compounds.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.319-323
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• 2010

Recently, Korean traditional raw rice wines (RRW) have received attention because they are a nutritious food with health properties. But the rapid deterioration of fermented RRW is one of the serious problems for brewing and marketing in the world beyond Korea. The goal of this study was to develop a way to enhance the quality and to lengthen the period of circulation of the RRW. A lactic acid bacterium was isolated from RRW. It was identified as Lactobacillus fermentum (98%) based on its biochemical properties, and 16S rRNA sequence. Treatments of RRW with gamma radiation and green tea extracts reduced the bacterial population except for yeasts and Lactobacillus in the RRW. This result suggested that the natural plant extracts and catechin products can be used as an effective natural storage agent.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.365-372
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• 2010

Irradiation has been recognized as a highly suitable tool to aid in the formation of hydrogel. The radiation process has various advantage, such as easy process control and the lack of necessity for initiators and crosslinker. In this study, the hydrogel containing the citrus fermentation gel for the wound healing were successfully synthesized. The strength of hydrogel was increased as a function of a increasing the concentration of citrus and the irradiation doses. In addition, this hydrogel have been evaluated by the cytotoxicity and animal experiment.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.151-157
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• 2011

Crosslinked SPEEK/PVDF membrane were prepared by EB radiation method with various contents of PVDF. The prepared membranes were subjected to a comparative study of proton exchange membranes for fuel cell appreciations. The crosslinked SPEEK/PVDF membranes were characterized by using DMA, DSC and SAXS. The DMA data indicate that the ionic modulus values and cluster $T_g$ decrease with increasing PVDF content. Thus, it was suggested that the number of clustering in the crosslinked membranes can be reduced with increasing PVDF content. The DSC results were shown that the degree of crystalline of the membrane increased with increasing PVDF content. The morphology of the crosslinkied membranes was shown that with increasing PVDF content, the number of crystalline domain of the SPEEK/PVDF membranes increased but ionic aggregation of the membranes decreased. The water uptake behavior, ionic exchange capacity (IEC) and proton conductivity were decreased with increasing PVDF content. The overall findings suggest that the crosslinked membranes offer the possibility for improving the performance of PEMFC, provided that the membranes have thermal and hydration stability.

• Journal of Radiation Industry
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• v.8 no.1
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• pp.17-22
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• 2014

In this study, we prepared CdTe/CdS solar cells using a thermal vacuum evaporation method. In particular, $CdCl_2$ treatment was attempted using this same method at $400^{\circ}C$ for 30 min. The prepared CdTe/CdS solar cells were investigated using Fouier transform infrared spectrometry (FTIR), field emission scanning electron microscopy (FE-SEM), and a solar simulator system including light absorption properties, morphological properties, and power conversion efficiency (PCE). In addition, we investigated the gamma-irradiation treatment at dose rates of 0 Gy, 500 Gy, 1 kGy, 10 kGy, and 30 kGy. The characteristics of gamma-irradiation treatment were studied based on the same method described above. In particular, it showed increased values as 0.826% higher than the non-irradiation of 0.448% from PCE analysis.

• Journal of Radiation Industry
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• v.6 no.2
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• pp.171-176
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• 2012

In this study, a crosslinked poly(styrene-butadiene-styrene) [SBS] block copolymers were prepared by using gamma ray irradiation method. The effects of various radiation doses on the degree of crosslinking, thermo property, and morphology of crosslinked SBS block copolymer were investigated. The degree of crosslinking of crosslinked SBS block copolymers were measured by gel-fraction and FT-IR. It was found that the degree of crosslinking of crosslinked SBS block copolymers increases with increase of the irradiation dose while the TGA result shows that the initial degradation temperature of irradiated SBS block copolymer was shifted to lower temperature with increasing irradiation dose. These results indicate that degradation reaction also occurs when SBS block copolymer is exposed to gamma ray irradiation for crosslinking reaction. The SAXS and FE-SEM results indicate that the phase separation of the styrene block and butadiene block was reduced with increasing irradiation dose.