• Journal of Life Science
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• v.10 no.1
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• pp.14-21
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• 2000

The experiments were performed using both batch and continuous column reactors. Batch biodegradation studies were performed under aerobic conditions to determine the biodegradable fraction of the natural organic matter (NOM) source. NOM source was evaluated for its biodegradability at three different UV irradiation conditions and compared to its biodegradability without UV irradiation. In continuous experiments, system operating parameters of empty bed contact time (EBCT), recycle ratio, and influent concentration affected the extent of biofiltration in the biofilters. The effluent UV254/DOC ratios fro the biologically active columns were consistently lower than the influent values, which indicated that the dissolved organic carbon (DOC) removed by biodegradation was not a significant part of the UV-absorbable material. The increase in UV254/DOC ratio was caused by the DOC decrease across the biofilter because there was essentially no difference between the feed and effluent UV254 absorbance values over time. The results of this research showed that biofiltration was an effective method for removing the biodegradable fraction of NOM from water supplies.

• Horticultural Science & Technology
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• v.29 no.5
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• pp.441-446
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• 2011

The effects of UV irradiation, as a hormetic stimulus, on the postharvest persimmon fruits (Diospyros kaki cv. Fuyu) were investigated in regards to the change of carotenoid contents and flesh softening, when the UV irradiation was combined with or without the pretreatment of 1-methylcyclopropene (1-MCP) as an ethylene action inhibitor. The major carotenoid pigments in persimmon fruits were ${\beta}$-carotene, lycopene and ${\beta}$-cryptoxanthin. Of them, the lycopene was a pigment, which increased markedly after harvest. UV irradiation increased the contents of ${\beta}$-carotene and lycopene, enhancing the skin color to scarlet. The treatment accelerated however also the softening of fruit flesh. But the softening of UV irradiated fruits could be delayed significantly by pretreatment with 1-MCP without reducing the advantageous effect of UV irradiation on the carotenoid increase.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.645-654
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• 1994

Photocatalytic oxidation conditions of reactant recirculation flow rate 275 mL/min, aeration rate 2 LPM and $UV+TiO_2+H_2O_2$(500 mg/L) proved to be appropriate for water including organic materials treatment. With increasing turbidity and suspended solids concentration, at turbidity 10 NTU-suspended solids concentration 29 mg/L the phenol degradation efficiency increased, which in turn decreased at turbidity 50 NTU-suspended solids concentration 170 mg/L, however no significant differences were observed, demonstrating similar results with those obtained at zero turbidity and suspended solids concentration. The degradation efficiency of phenol decreased with increasing influent phenol concentrations. The $UV+TiO_2+H_2O_2$ photocatalytic advanced oxidation process conducted is considered to be possibly applied to the drinking water treatment, and the post-treatment process of biological wastewater treatment.

• 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.

• Food Science and Preservation
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• v.15 no.6
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• pp.922-926
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• 2008

The effect of UV-C irradiation on microbial growth and the quality of imported dried filefish and octopus during storage was examined. Samples of imported dried filefish and octopus were irradiated at 0, 5, 10 and $20\;kJ/m^2$ and stored for 3 months at $20^{\circ}C$ or for 6 days at $4^{\circ}C$. Exposure times of 5 min 33 sec, 11 min 6 sec, and 22 min 12 sec were used. UV-C treatment of the imported dried filefish and octopus decreased the populations of aerobic bacteria, yeasts and molds in proportion to radiation dose. Compared to the control, total aerobic bacteria, and yeast and mold populations were significantly lower (1-2 log CFU/g) with UV-C treatment of $20\;kJ/m^2$. UV-C irradiation caused negligible changes in the Hunter color L, a and b values. These results indicate that UV-C irradiation could be useful in inhibiting microbial growth on imported dried fish without impairing quality during storage.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.69-80
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• 2007

Among the photoactive semiconductors such as $TiO_2,\;ZnO,\;Fe_2O_3,\;WO_3,\;and\;CdSe,\;TiO_2$ is the most widely used as photocatalyst in different media, because of its lack of toxicity and stability. In this study, the effects of titanium dioxide were investigated to obtain the information of physiological change in rice plant. Light-adapted Chlorophyll flourescence index decreased and relative electron transport rate of rice leaves was activated by titanium dioxide under $2,400\;{\mu}mol\;m^{-2}\;s^{-1}$ PAR (Photosynthetic active radiation). Relative electron transport rate of rice leaf treated with titanium dioxide 10 ppm was high in order of $2,400\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR,\;2,200\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR,\;450\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR$ and titanium dioxide 10 ppm (45.1%), control (32.4%), diuron 10 ppm (15.3%) under $2,400\;{\mu}mol\;m^{-2}\;s^{-1}\;PAR$. Titanium dioxide increased photosynthesis of the rice leaf under $13.6\;KJ\;m^{-2}\;day^{-1}$ UV-B only. With titanium dioxide 20 ppm, reduced UV-B ($0.15\;KJ\;m^{-2}\;day^{-1}$) intensity changed the induction of proteins and twenty-five proteins were identified. Among them, seventy proteins were up-regulated, four proteins were down-regulated and four proteins were newly synthesized. Function of these proteins was related to photosynthesis (52%), carbohydrate metabolism (4%), stress/defense (8%), secondary metabolism (4%), energy/electron transport (4%), and miscellaneous (28%).

• 프린팅코리아
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• v.12 no.5
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• pp.93-93
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• 2013

문덕인쇄(대표 박종하)는 최근 동양잉크(주) CTP사업부가 보급하는 화광수마(HDGE)의 128채널 UV CTP를 설치했다. 이번에 설치한 CTP는 국전 기준으로 시간당 최대 47장을 출력할 수 있는 고성능 UV CTP로 박종하 대표는 보다 많은 물량을 안정적으로 처리할 수 있게 돼 기대가 크다고 밝혔다.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.1
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• pp.61-72
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• 2014

Study on effluent organic matter (EfOM) characteristic and removal efficiency is required, because EfOM is important in regard to the stability of effluents reuse, quality issues of artificial recharge and water conservation of aqueous system. UV technology is widely used in wastewater treatment. Many reports have been conducted on microbial disinfection and micro pollutant reduction with UV treatment. However, the study on EfOM with UV has limited because low/medium pressure UV lamp is not sufficient to affect refractory organics. The high intensity of pulsed UV would mineralize EfOM itself as well as change the characteristics of EfOM. Chlorine demand and DBPs formation is affected on the changed amounts and properties of EfOM. The objective of this study is to investigate the effect on EfOM, chlorine residual, and chlorinated DBPs formation with low pressure and pulsed UV treatment. The removal of organic matter through low pressure UV treatment is insignificant effect. Pulsed UV treatment effectively removes/transforms EfOM. As a result, the chlorine consumption is changed and chlorine DBPs formation is decreased. However, excessive UV treatment caused problems of increasing chlorine consumption and generating unknown by-products.

• Journal of Korean Society on Water Environment
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• v.25 no.1
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• pp.96-101
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• 2009

The aim of this research was to apply experimental design methodology to optimizetion the photolytic degradation of N-nitrosodimethylamine (NDMA). Reactions were mathematically described as a function of parameters such as pH, initial NDMA concentration, and UV intensity using the Box-Behnken method. The results showed that the responses of NDMA removal (%) in photolysis were significantly affected by the synergistic effect of linear term of pH, initial NDMA concentration and UV intensity. The application of Response Surfase Methodology (RSM) using the Box-Behnken method yielded the following regression equation, which is an empirical relationship between the removal (%) of NDMA and test variables in coded unit: Y = 50.929 + 16.073(UV) - 7.909(NDMA) - 27.432(pH) - 11.385(UV)(NDMA) - 7.363(UV)(pH) +13.811(NDMA)(pH). The model predictions agreed well with the experimentally observed result ($R_2(ad.)=89%$).

• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.142-144
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• 2005

Main purpose of this study is a improved efficiency of Organic light emitting diodes(OLEDs) concerning $UV/O_3$ treatment. We investigated the efficiency of OLEDs by $UV/O_3$ treatment of ITO surface. We measured current density-voltage, luminance-voltage characteristics in different $UV/O_3$ treatment time and observed ITO surface roughness by using AFM(Atomic Force Microscope). The fundamental structure of the OLEDs was $ITO/NPB/Alq_3/LiF/Al$. We performed $UV/O_3$ treatment and found that $UV/O_3$ treatment enhanced the performance of OLEDs. We also found that change of surface roughness according to difference time a $UV/O_3$ treatment