• Macromolecular Research
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• v.17 no.10
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• pp.813-816
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• 2009

• Journal of Radiation Industry
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• v.7 no.1
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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 Industry
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• v.5 no.3
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• pp.253-258
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• 2011

Acetylsalicylic acid (ASA) has been issued recently in contaminated water environments because of potential impacts on ecosystem and public health. This study was aimed at investigating the possibility of ASA degradation using gamma ray irradiation. In addition, the use of sodium persulfate, hydrogen peroxide, ferrous sulfate were tested in order to examine a synergistic effect with gamma ray. The absorbed dose was ranged from 0.2 to 10 kGy and the concentration of oxidants were from 0.1 to 10 mM in this study. The concentration of ASA was gradually decreased corresponding to the increase of the absorbed dose. When soudium persulfate was simultaneously applied, most of the parent compound was completely degraded even at a low dose of 0.8 kGy. The removal efficiency of total organic carbon was 90% even at the highest dose of 10 kGy without sodium persulfate. However, the efficiency was dramatically enhanced up to 98% at the same dose by adding 10 mM of oxidants. It was suggested that hydroxyl radical ($OH{\cdot}$) and sulfate radical ($SO{_4}^-{\cdot}$) were formed in the system and made roles in degrading ASA at the same time.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.107-112
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• 2011

Electron beam-induced crosslinking of polycaprolactone (PCL) films containing various crosslinking agents (CAs) was investigated in this study. PCL films containing various CAs prepared by a solution casting method were irradiated by electron beams at various absorption doses and the irradiated PCL films were investigated in terms of their crosslinking degree, thermal and mechanical properties, and biodegradability. Based on the results of the crosslinking degree measurement, triallyl isocyanurate was found to be most effective for the electron-beam induced crosslinking of PCL films. The results of the UTM, DMA, and TMA revealed that the thermal and mechanical properties of the crosslinked PCL films were greatly improved in comparison to those of the pure PCL. The results of the enzymatic degradation test revealed that the biodegradability of the crosslinked PCL films was reduced in comparison to that of the pure PCL.

• Journal of Radiation Industry
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• v.12 no.4
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• pp.343-348
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• 2018

Preliminary study was perfomed to develop a biocompatible filter material using radiation energy. Electrosppined PLLA nano sheets were surface-modificated with hydrophilic groups(acrylic group) by using radiation. The physico-chemical and morphological characteristics of modified PLLA sheets were measured by ATR, SEM, contact angle, and hydrophilic (acryl group) introduction rate (TBO). As a result, there was no morphological(fiber structure) structure change due to radiation, and it was confirmed that an acrylic group was successfully introduced onto PLLA fiber sheet by radiation.

• Journal of Radiation Industry
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• v.5 no.1
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• pp.63-67
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• 2011

A comparative experiment was conducted to compare the effects of persulfate with gamma radiation on the disinfection efficiencies against Escherichia coli K12. The microorganism used for the disinfection experiments were prepared by transferring a bacterial stock culture into a 50 ml nutrient broth an incubating for 24 hrs at $37^{\circ}C$. The initial concentration of the harvested culture was approximately $10^7$ to $10^9CFU\;ml^{-1}$. The culture solution was irradiated at different absorbed doses of 0.1, 0.2, 0.3, 0.4, 0.5, 0.7, and 1 kGy, respectively. The disinfection efficiency of persulfate with gamma radiation of 0.3 kGy against Escherichia coli K12 was 97.2% and while the gamma radiation only was 90.01% at 0.3 kGy. Therefore, it could be thought that addition of persulfate in the disinfection of Escherichia coli K12 can enhance the disinfection efficiency when it is used together with gamma radiation.

• Journal of Radiation Industry
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• v.5 no.2
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• pp.159-164
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• 2011

A variety of natural polymers have been used as tissue engineering scaffolds, drug delivery system, and cosmetic materials due to their higher biocompatibility and water uptake. As a major component of extracellular matrix, hyaluronic acid consisting of D-glucuronic acid and N-acetylglucosamine has been popularly used as a hydrogel material. Even though it has good properties to be used in the tissue engineering and cosmetic industry, its higher viscosity has limited a potential use in a variety of applications; only low content should be applied in preparing above products. In the present study, we investigated the effect of electron beam irradiation on the properties of hyaluronic acid. Hyaluronic acid paste containing low contents of water changed to solution after electron beam irradiation ranging from 1 to 10 kGy, which didn't exhibit any alteration of surface properties and morphological change after freeze-drying. However, its viscosity was significantly decreased as absorbed dose increased, which was approximately one by hundred in comparison with the viscosity of original hyaluronic acid solution with same concentration. In addition, it can still interact with positive charged chitosan generating polyelectrolyte complex. Therefore, only viscosity was decreased after electron beam irradiation, whereas other properties of hyaluronic acid maintained. Consequently, these hyaluronic acids with lower viscosities can be used in a variety of applications in tissue engineering, drug delivery, and cosmetic industry.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.89-94
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• 2012

Three-dimensional network hydrogels were prepared by ${\gamma}$-irradiation of aqueous solutions of poly(vinyl alcohol) (PVA) and glycerol (Gly). Oven-drying was used to measure the gel fraction (G), hydration (H) or swelling behavior (S) of the prepared hydrogels. This study made a hypothesis that hydrogen bonds due to addition of glycerol and change of dry states such as freeze-drying (FD), room-drying (RD) and oven-drying (OD) acts on the G, H, and S. Interesting results on the hydrogen bonding effect in the prepared hydrogels are monitored at different drying conditions. The FD samples have a higher G values with increase in glycerol content as compared with the OD and RD samples. The formation of strong hydrogen bonding network among Gly molecules and hydrogel matrix was considered as the main driving force, resulting in the changes in the G, H, and S of the hydrogels under different drying conditions.

• Journal of Radiation Industry
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• v.5 no.3
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• pp.191-196
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• 2011

The economic scale of nuclear application is a good indicator to show how the radiation technology is useful and contribute to improve public welfare and living standard. Recent research in Japan shows that the economic scale of nuclear field was 4,112 B¥ for radiation application(46%) and 4,741 B¥ for nuclear energy (54%) playing a role of "two wheels of one cart" in nuclear field and the total 8,853 B¥ constitutes 1.8% of gross domestic products (GDP). The radiation application consisted of 2,295 B¥ (56%) in industry (semiconductor, sterilization, nondestructive testing, radiation processing of tires, etc.), 1,538 B¥ (37%) in medicine (therapy and diagnosis such as X-ray, nuclear medicine, computed tomography, etc.) and 279 B¥ (7%) in agriculture (mutation breeding, food irradiation, sterile insect technique, etc.). Radiation application by ${\gamma}$-ray, electron beam and ion beam is steadily increasing in Japan.

• 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.