• 한국물환경학회지
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• 제26권6호
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• pp.1034-1039
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• 2010

Variation of formation potential of THM (THMFP) by chlorination of humic acid and characteristics of water quality with ${\gamma}$-ray irradiation were investigated, which were divided into two categories by the order of ${\gamma}$-ray irradiation and chlorination in water treatment process. The group A consisted of the ${\gamma}$-ray irradiation followed by chlorination process of humic acid, and the group B consisted of the chlorination followed by ${\gamma}$-ray irradiation process. The pH, ORP, $UV_{254}$, and DOC decreased rapidly with an increase in ${\gamma}$-ray irradiation of 3 kGy. while conductivity was little changed. Maximum degradation ratio of chloroform in THMs of group A was 82%, while that in group B was 69%. No brominated THMs were detected at high irradiation (>3 kGy). We found that group A water treatment process was more effective in lowering the THMFP than that of group B.

• 방사선산업학회지
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• 제5권3호
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• pp.249-252
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• 2011

Lignin is one of the natural macromolecules. Every year large amount of lignin arises from the cellulose production as a by-product worldwide. The use of lignin as a precursor to carbonaceous materials has gained interest due to its low cost and high availability. Therefore, we improved the properties of alkali-lignin by exposing to gamma ray in this study. The alkali-lignin is irradiated by Gamma ray irradiation with varying doses. The char yields of alkali-lignin were investigated by increasing up to 50 kGy. The cross-linking and bond scission of alkali-lignin occur simultaneously during gamma ray irradiation. The crosslinking was predominantly accelerated by gamma ray irradiation up to 50 kGy. Bond scission predominantly occurs between 50 and 500 kGy. ESCA analysis indicated that the alcoholic carbon increase up to 50 kGy. Solution viscosity was increased as absorbed dose increased up to 20 kGy. In addition, the aromatic ring was not influenced by irradiation at doses ranging from 20 to 500 kGy as shown in FT-IR results.

• 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.

• Fibers and Polymers
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• 제5권3호
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• pp.225-229
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• 2004

The effect of UV and $^60{Co}$ gamma radiations on the physical and mechanical properties of nylon 6 mono-filaments with different draw ratios has been studied. Specimens were exposed to either up to 25 Mrad of gamma or up to 168 hrs of intense UV irradiation. The results show that nylon mono-filaments exposed to gamma rays, with much higher quantum energy than UV, undergo a larger extent of molecular chain scission. Higher irradiation dose also results in the production of insoluble, macroscopic three-dimensional cross-linked network structure. The amorphous regions with a lower density of cohesive energy (lower molecular orientation) show a higher extent of cross linking reaction whereas amorphous regions with a higher density of cohesive energy (higher orientation) show higher extent of chain scission reaction, irrespective of UV ray or gamma ray irradiation.

• 한국응용곤충학회지
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• 제33권4호
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• pp.263-269
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• 1994

궐련벌레(Lasioderma serricorne F)가 제품담배내 오염되었을때의 방제방법으로 감마선 이용법을 선전 방제효과를 조사하였다. Gelatin capsules에 공시충을 넣은 다음 감마선을 조사해 본 결과 0.8kGy이상의 선량에서 난태는 모두 살충되었고 용태나 성충때 및 유충태는 0~30%가 살충되었다. 몇가지 제품담배값내에 공시충을 함유한 gelatin capsules이 삽입된 궐련을 넣은후 감마선 조사시의 궐련벌레 충태별 방제효과도 동일한 결과를 얻었다. 감마선의 영향을 받은 궐련벌레의 성충 및 유충태를 인공먹이로 사육해 본 결과 차세대 개체군 증식이 확인되지 않았다. 감마선에 노출된 궐련벌레의 각 충태는 선량이 높아질수록 생존기간이 짧아졌으며 4령 유충이 처리 공시충중 가장 오래 생존하였다. 감마선에 노출된 제품담배의 고유향기나 맛은 선량 증가에도 영향을 받지 않았다. 감마선이 처리된 제품담배의 포갑지나 궐련지 및 은박지 등은 고유의 색도 또한 변화하지 않았다.

• 전기의세계
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• 제22권4호
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• pp.7-10
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• 1973

The characteristics of all the instruments and materials used in atomic industry is changed due to radiation damages by the effects of radiation activities. In this study, when the Carbon Resistor, main element of electrical circuits, is irradiated by Gamma-Ray, variations in its electrical properties have been investigated. The following results are obtained: 1) The resistance value in Carbon Resistor is exponentially increased as the quantity of irradiation by Gamma-Ray is increased, but in case of more than 10$^{6}$ R/hr. of quantity of irradiation it has saturated-state value. 2) The rate of change inrestistance value has been independent on the intensity of Gamma-Ray source when Carbon Resistor is irradiated in the same quantity of irradiation. 3) The resistance value in irradiated Carbon Resistor has not been varied with elapse of time. 4) The more the distance from the Carbon Resistor to the Gamma-Ray source the more greatly the resistance value is decreased and that it has been shown that the more quantity of irradiation by Gamma-Ray, the greater the rate of decrease in resistance value. Through the above results it has been concluded that the measurement values obtained by the high-precision instruments in the radiation field have to be corrected with proper consideration to radiation damages.

• 방사선산업학회지
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• 제2권1호
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• pp.9-14
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• 2008

Livestock wastewater containing high concentrations of organic matters and ammonia-nitrogen has been known as one of the recalcitrant wastewater. It is difficult to treat by conventional wastewater treatment techniques. This study was carried out to evaluate the feasibility of zeolite ion exchange and gamma-ray irradiation treatment of livestock wastewater. The removal efficiencies of $SCOD_{Cr}$ and $NH_3-N$ were significantly enhanced by gamma-ray irradiation after zeolite ion exchange as a pre-treatment. However, the effects of zeolite particle size on the $SCOD_{Cr}$ and $NH_3-N$ removal efficiencies were insignificant. These results indicate that the combined process of zeolite ion exchange and gamma-ray irradiation has potential for the treatment of livestock wastewater.

• 한국안전학회지
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• 제19권3호
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• pp.26-31
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• 2004

The radiation-induced changes taking place in poly(vinylidene fluoride) (PVDF) exposed to $^{60}Co$ $\gamma-ray$ irradiation were investigated in correlation with the applied doses. Samples were irradiated in air at room temperature by $^{60}Co$ $\gamma-ray$ to doses in the range of 200 to 1000kGy. Various properties of the irradiated PVDF were studied using FTIR, differential scanning calorimetry (DSC), gel fraction and elongation. $^{60}Co\gamma-ray$ irradiation was found to induce changes in chemical, thermal, mechanical and structural properties of PVDF and such changes vary depending on the radiation dose.

• 환경위생공학
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• 제13권2호
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• pp.106-114
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• 1998

This study was carried out for the purpose of industrial reuse of effluent released from activated sludge unit by $\gamma $-ray irradiation technique. The dissolved organic carbon in the effluent of an activated sludge unit is mostly refractory or inert material which are difficult to be degraded by micro organism. The effluent generated from activated sludge unit was irradiated with Co$^{60}$ $\gamma $-ray under condition of air bubbling. The effects of irradiation on the pH, COD, TOC, color, molecular weight distribution were investigated by membrane filtration and u.v.-spectrum analysis. With increasing dose, the TOC was decreased smoothly. The COD was increased at lower dose, while the COD was decreased at higher dose. The TOC and COD, however, were decreased smoothly when TiO$_{2}$ was added to the solution. It was thought that the differential decreasing trend of COD and TOC in according to the absence or presence of TiO$_{2}$ was due to the molecular weight distribution shifted from group of higher molecular weight to group of lower one which are more easy to be decomposed. The removal efficiency of color was 71.5% and it was increased to 85.7% when TiO$_{2}$ was added to the solution. The $\gamma $-ray irradiation was effective on the production of chlorine.

• 전기의세계
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• 제23권3호
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• pp.67-69
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• 1974

The electric characteristics of all the instruments and materials used in atomic field is changed due to radiation damages by the effects of radio activities. In this study, when the condenser is radiated by Gamma-ray, variations in its electric properties have been investigated. The following results are obtained. (1) The capacitance in O.F paper condenser is exponentially increased as the quantity of irradiation by Gamma-ray is increased, but polyethylene, ceramic, chemical, neostyrene, mylar condenser are decreased. and in case of more than 10$^{7}$ of irradiation it has saturated state, (2) The breakdown voltage and the .delta. in condensers except the O.F paper condenser are exponentially increased as the quantity of irradiation by Gamma-ray is increased but in case of more than 10$^{7}$ .gamma. of irradiation it has decreased.