• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1995.10a
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• pp.115-117
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• 1995

This paper describes the O.T aging analysis by non-destructive electrical and UV/visible method. Non-destructive diagnosis method is tan8 test. Also the new method of the aging analysis, UV/visible method was introduced in this paper and compared with the non-destructive electrical method. The UV/visible test could be useful method for the O.T aging electrical diagnosis such as non-destructive electrical method.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1851-1853
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• 1996

In this paper the criteria for insulating oil condition of pole transformer were suggested by applying the UV-Visible spectrophotometric method. Ageing of insulating oil caused the change in absorbances of oil os well os the deterioration of electrical properties of oil. By comparing the electrical properties such as $tan{\delta}$ and breakdown voltage with the UV-Visible absorbances of oil, criteria for absorbance values determining oil condition were established. This UV-Visible spectrophotometric method might be applied in ageing analysis of oil and be expected to replace the current method.

• Food Science and Preservation
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• v.20 no.1
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• pp.45-51
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• 2013

This study was conducted to evaluate the changes in the quality of rice wine (Makgeolli) treated with UV-C and electron beam (EB) irradiation during its storage at $4^{\circ}C$ for 15 days. The EB irradiation was found to be more effective than the UV-C irradiation for microbiological control. The pH tended to be increased by UV-C, EB irradiation, and storage period. Acidity was significantly higher in rice wine treated with EB irradiation than those of control and UV-C irradiation during storage period. The $L^*$-value of the samples treated with UV-C and EB irradiation tended to be proportionately higher than that of the control, but this was not consistent during storage period. The $a^*$-value of the sample treated with EB was higher than that of the others, but this was not consistent during the storage period. The reducing sugar content was higher in the control at day 0, but it rapidly decreased compared with the control during the storage. The results indicate that EB irradiation was more effective than UV-C irradiation in controlling microorganisms of rice wine. However, a further study is needed to minimize the rice wine quality deterioration caused by UV-C or EB irradiation during storage.

• Korean Journal of Environmental Biology
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• v.17 no.1
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• pp.1-9
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• 1999

Numerous observations revealed strong evidence of increased middle ultraviolet radiation or UV-B (280 ~ 320 nm) at the earth's surface resulting from stratospheric ozone depletion. UV is the waveband of electromagnetic radiation which is strongly absorbed by nucleic acids and proteins, thus causing damage to living systems. It has been recorded in the East Sea, Korea that solar UV-B impinging on the ocean surface penetrates seawater to significant depths. Recent researches showed that exposure to UV-B for as short as 2h at the ambient level (2.0 Wm$^{-2}$) decreased macroalgal growth and photosynthesis and destroyed photosynthetic pigments. These may suggest that UV-B could be an important environmental factor to determine algal survival and distribution. Some adaptive mechanisms to protect macroalgae from UV-damage have been found, which include photoreactivation and formation of UV-absorbing pigments. Post-illumination of visible light mitigated UV-induced damage in laminarian young sporophytes with blue the most effective waveband. The existence of UV-B absorbing pigments has been recognized in the green alga, Ulva pertusa and the red alga, Pachymeniopsis sp., which is likely to exert protective function for photosynthetic pigments inside the thalli from UV-damage. Further studies are however needed to confirm that these mechanisms are of general occurrence in seaweeds. Macroalgae together with phytoplankton are the primary producers to incorporate about 100 Gt of carbons per year, and provide half of the total biomass on the earth. UV-driven reduction in macroalgal biomass, if any, would therefore cause deleterious effects on marine ecosystem. The ultimate impacts of increasing UV-B flux due to ozone destruction are still unknown, but the impression from UV studies made so far seems to highlight the importance of setting up long-term monitoring system for us to be able to predict and detect the onset of large -scale deterioration in aquatic ecosystem.

• Journal of the Korea Institute of Building Construction
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• v.14 no.4
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• pp.359-368
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• 2014

Photocatalytic cement has been receiving attention due to its high oxidation power that reduces nitrogen oxide, thus contributing to a clean atmospheric environment. However, there has not yet been a thorough investigation on the effect of photocatalytic reactions on the durability of cementitious material, the parent material. In this study, photocatalytic cement samples were exposed to nitric oxide gas and UV along with cycles of wetting and drying to simulate environmental conditions. The surface of samples was characterized mechanically, chemically, and visually during the cycling. The results indicate that that the photocatalytic efficiency decreased with continued NO oxidation. The pits found from SEM indicated that chemical deterioration, such as acid attack or leaching, did occur. However, this was not confirmed by X-ray diffraction. The hardness was not affected, probably due to the formation of CSH as evidenced by the XRD pattern. In conclusion, it was found that photocatalysis could alter cementitious materials both chemically and mechanically, which could further affect long-term durability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.1
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• pp.167-174
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• 2010

In this paper, the ultraviolet rays images and aging judgement caused by surface contamination on 22.9[kV] class insulators was defined. UV images represented by the corona discharge are divided 3 types such as sunflower, jellyfish, amoeba and in detail, there are classified the progress mechanism of eight. In the field which is installed the power facilities, immediately, this judgement method can be found out the deteriorated parts of the power facilities. These steps are possible to judge the deterioration of power facilities through reliable data. Hereafter, this study as the diagnostic technology suitable for the sites is used.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.147-152
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• 2008

This paper describes the breakdown poperties of porcelain and polymer insulators using the UV camera. The experiment was carried out using condition of voltage at the KS C IEC 60060-1(2006). As these results, corona discharge in porcelain insulator was generated the weakness point of insulator union. And the corona discharge of polymer insulator happened in union of power source. Also, we could confirm easily weakness part of these insulators by ultraviolet image through the corona discharge. Besides, in the comparison with the exciting technique of ultrasonic detection, it confirmed that deterioration steps are corrected. These steps are possible to judge the deterioration of power facilities through reliable date. Hereafter, this study as the diagnostic technology suitable for the sites is used.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.5
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• pp.94-100
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• 1996

Criteria for insulating oil condition of pole transformer were suggested by applying the UV-Visible spectrophotometric method. Aging of insulating oil caused the change in absorbances of oil as well as the deterioration of electrical properties of oil. By comparing the electrical properties such as tan$\delta$ and dielectric breakdown voltage with the UV-Visible absorbances of oil, following criteria for absorbance values determining oil condition were established, fair condition is below 0.580, need attention is 0.580-0.900 and poor condition is above 0.900. This W-Visible spectrophotometric method may be applied in aging analysis of oil and expected to replace the current visual method. It is necessary to develop cheap, light and portable UV-Visible spectrophotometer in near future for field application.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.377-384
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• 2005

Algae causes not only the eutrophication of lake, but also the deterioration of drinking water process. Especially, algogenic organic matters(AOM) are assumed as disinfection by-products(DBPs) precursors like humic and fulvic acids. In this study, it was investigated the characteristics changes of algogenic organic matter(AOM) by prechlorination and coagulation treatment. Evaluation of enhanced coagulation and applicability of UV oxidation process were also evaluated as the drinking water treatment system for the eutrophicated water source. prechlorination was effective process for algae removal but caused releasing of dissolved organic matter(DOC) into water due to the destruction of algae's cell. In coagulation treatment with Fe(III) coagulant, reaction pH is an important factor for the removal of AOM and triholomathanes(THMs). At pH 5, removal efficiency of DOC and THMs were dramatically improved by 50% and 28%, respectively, in comparison with the conventional coagulation treatment at about pH 7. Photo-Fenton($UV/H_2O_2/Fe^{3+}$) process among the UV oxidations is the most effective system to remove AOM, but its removal efficiency was lower than that of enhanced coagulation treatment at pH 5.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.41-42
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• 2012

High temperature / high pressure spray equipment using a conventional method, unlike spray polyurea adjustable pot life and yellowing caused by UV light and chemicals do not occur, or discoloration of Self-Leveling Type of rugged hand-polyurea resin for technology development is underway. This new concept of polyurea resin roller, brush, airless spray, and they installed easily using the unfamiliar labor, and curing time of approximately four hours to gain control of the glass because it is Pot. Construction, but does not like the spray polyurea resin, compared to the existing degradation of the adhesion strength is concerned. In this study, Self-Leveling Type Manual of polyurea resin adhesion strength of target deterioration Let's minimize problems by reviewing existing domestic and infrastructure long-term durability for long life of the facility is to obtain.