• 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.

• 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

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.240-240
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• 2010

In this paper, in these case of photoelectrode using UV treatment after oxygen solar conversion efficiency is increased. According to oxygen injection UV treatment will removal residual organics and increase the TiO2 surface area but also UV treatment can affect the same chemical action of ozone treatment. More porous networks and larger porosities were obtained in the TiO2 films prepared UV treatment after oxygen injection.

• Journal of the Microelectronics and Packaging Society
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• v.21 no.1
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• pp.41-44
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• 2014

We employed UV-Ozone treatment method for the fabrication of dense and highly conductive nanoparticle thin films. We demonstrated the UV-Ozone treatment effect on the silver nanoparticle thin films as a function of time and temperature. The capping layers of nanoparticles were decomposed after UV-Ozone treatment and dense nanoparticle thin films were obtained. Moreover, electrical and mechanical properties of the thin films after UV-Ozone treatment were measured by using resistance measurements under tension in an in-situ tensile tester. The initial resistance of nanoparticle thin films was decreased by 82.6% with optimized UV-Ozone treatment condition of $150^{\circ}C$ for 20 minutes.

• Journal of Korea Foresty Energy
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• v.19 no.1
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• pp.1-6
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• 2000

This study was carried out to investigate the growth responses of Pinus densiflora seedlings to enhanced UV-B environment for 16 weeks in the field condition. The seedlings were treated with one of three levels of UV-B dosages - ambient UV-B, ambient + 3.2, and ambient + 5.2 KJ m$^{-2}$day$^{-1}$ and the irradiation was performed at the stage before the germination, the fully expanded cotyledon, and the primary needles grown more than 0.8cm in length of the seedlings, respectively. Enhanced UV-B irradiation reduced the height and the root collar diameter growth, and dry mass production of the seedling, and T/R ratio was increased by the UV-B treatment. Difference in seedling growth was observed by difference in time of the UV-B treatment. Among the seedlings which were treated with ambient - 3.2 KJ m$^{-2}$day$^{-1}$, height and root collar diameter growth was relatively high in the seedling received the UV-B treatment at the stage before the germination. The lowest dry mass production was observed in the seedlings received the UV-B at stage of cotyledon both in two levels of enhanced UV-B treatment. Chlorophyll concentration was reduced by enhanced UV-B irradiation, and chlorophyll a/b ratio was increased by the UV-B treatment.

• Journal of Environmental Health Sciences
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• v.27 no.4
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• pp.93-98
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• 2001

Wastewaters produced in textile industrial processes contain dyes which are not easily amenable to biological treatment. The object of this study is to determine the post-treatment system of biological process for the textile wastewater by comparing three different types of chemical process, which were 1) post-treatment by ozone or UV, 2) post-treatment by coagulation,3) post-treatment by ozone or UV followed by coagulation. In an application ozone or UV as a post-treatment, color was generally decreased with time, however, SCOD removal effect was not that good. When coagulation was used as point-treatment process, the effluent quality was satisfying. Therefore, the application of coagulation process as a post-treatment of biological process would be more desirable than that as a ozone or UV.

• Journal of Plant Biotechnology
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• v.1 no.2
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• pp.117-121
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• 1999

Effects of jasmonic acid treatment, UV-B and white light treatment on the anthocyanin biosynthesis and cell growth were investigated using the cell suspension culture system of grape (Vitis vinifera L.). Cell growth was not affected by white light irradiation, while it was remarkably suppressed by UV-B irradiation from 8 to 32 h. Anthocyanin accumulation dramatically increased after 16 h from irradiation of UV-B. Simultaneous treatment of jasmonic acid and UV-B increased anthocyanin accumulation by 10-fold. The cell division was restored when anthocyanin was abundantly accumulated after 32 h from UV-B irradiation. Optimum concentration of jasmonic acid was found to be 5 uM for maximum accumulation of anthocyanin. Application of jasmonic acid to grape suspension cells rapidly induced the expression of CHS gene after 2 h from treatment and showed maximum level at 32 h. Simultaneous treatment of jasmonic acid and light also induced CHS gene expression after 2 h, but the maximum level of CHS transcript was observed at 16 h with white light and 8 h with UV-B exposure. The synergistical effects could be explained by the defense mechanism that UV irradiation is mediated in part by alterations in JA and its signaling pathway.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.1
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• pp.6-9
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• 2010

Surface properties of polytetrafluoroethylene(PTFE) films fabricated by rf-magnetron sputtering system with UV surface treatment were investigated to increase water contact angle for their hydrophobic property. We found that the surface morphology and water contact angles of PTFE film modified as a function of the UV treatment times using UV-irradiation were influenced. The water contact angle of PTFE film with optimized UV treatment time for 15 minute showed a high hydrophobicity compared with the film without any surface treatment. We thought that it was due to the energy change of PTFE surface with an adhesion improvement to the glass surface as a smoothing a rough surface with needle-shape and/or the enhancement of an interface property as a removing some defects on the surface like a cleaning effect.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.5
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• pp.685-692
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• 2012

UV technology is widely used in water and wastewater treatment. Many researches have been conducted on microbial disinfection and micro pollutant reduction with UV treatment. However, the study on NOM with UV has limited because low/medium pressure UV lamp is not sufficient to affect refractory organics such as NOM. Pulsed UV treatment using UV flash lamp can be operated in the pulsed mode with much greater peak intensity. The pulse duration is typically in microseconds, whereas the interval between pulses is in the order of milliseconds. The high intensity of pulsed UV would mineralize NOM itself as well as change the characteristics of NOM. Chlorine demand and DBPs formation is affected on the changed amounts and properties of NOM. The objective of this study is to investigate the effect on NOM, chlorine residual, and chlorinated DBPs formation with pulsed UV treatment.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.2
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• pp.126-137
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• 2003

The feasibility study of UV-disinfection system was performed for disinfection of effluent from wastewater treatment plant. Three low-pressure UV lamps of 17, 25, and 41 W were examined with various flow rates. Low-pressure UV lamps of 17W were examined with various turbidity, DOM (dissolved organic matter), and SS (suspended solid). The pilot plant was a flow-through type UV-disinfection system, and the range of exposure time varied from 5 to 40 seconds, turbidity from 0 to 40 NTU, DOM from 0 to 30 mg/L, and SS from 10 to 40 mg/L. The 41W lamp demonstrated complete disinfection showing no survival ratio in all the experimental conditions, and generally 17W and 25W lamps also showed high removal ratio over 97%. For the same UV dose (UV intensity times exposure time), high intensity-short exposure conditions showed better disinfection efficiency than low intensity-long exposure conditions. While the effects of turbidity and DOM were not apparent, the effects of SS was significant on the disinfection efficiency which indicates that SS control before UV-disinfection appears to be necessary to increase removal efficiency. Considering characteristics of effluent from existing wastewater treatment plants, cost-effectiveness, stable performance, and minimum maintenance, the flow-through type UV-disinfection system with high intensity and low-pressure lamps was thought to be a competitive disinfection system for wastewater reclamation.