• Bulletin of the Korean Chemical Society
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• v.30 no.8
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• pp.1798-1804
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• 2009

In this study, we have studied on improved performance of carbon nanotubes/titanium (CNT/TiO2) structure electrode for methylene blue (MB). The composite electrodes consisting of CNTs and a titanium oxide matrix with phenol resin binder was fabricated with a mixture method. The chemical and morphological structure of CNT/Ti$O_2$ composites were characterized by means of BET surface area, X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-Vis absorption technique, Raman spectroscopy and energy dispersive X-ray (EDX). The electrode showed a remarkably enhanced performance for MB oxidation under UV illumination with or without electro-chemical reaction (ECR). Such a remarkably improved performance of the CNT/Ti$O_2$ structure electrode might be due to the enhanced MB oxidation by electro- and photo-generated electrons and holes in the CNTs and Ti$O_2$ under UV illumination with or without ECR.

• Carbon letters
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• v.9 no.3
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• pp.195-199
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• 2008

A nanocomposite consisting of $Fe_3O_4$ and MWCNT was produced via sol-gel technique using $FeCl_3$ along with MWCNT by calcination at $300^{\circ}C$. The degradation effect of rhodamine B dye has been investigated under UV illumination in a darkroom. The degradation reaction was studied by monitoring the discoloration of dye as a function of irradiation time using UV-visible spectrophotometeric technique. The $Fe_3O_4$-MWCNT samples have continuous degradation ability under the UV illumination with the first order kinetics and the dye removal was better than in the pristine $Fe_3O_4$. The resultant composite catalyst was found to be efficient for the photo-Fenton reaction of the dye.

• Transactions on Semiconductor Engineering
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• v.1 no.1
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• pp.9-13
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• 2023

An AlGaN/GaN heterojunction-based hydrogen sensor with SnO₂ nanoparticles/Pd catalyst layer was fabricated for room-temperature hydrogen detection. The fabricated sensor exhibited unstable drift in standby current when it was operated at room temperature. The instability in the sensing signal was dramatically improved when the sensor was operated under UV illumination.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.3
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• pp.365-371
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• 2011

Most recently issued paper money includes security patterns that can be only identified by ultra violet (UV) illuminations. We propose an automatic extraction method of UV patterns for paper money inspection systems. The image acquired by camera and UV illumination is transformed to input data through preprocessing. And then, the Gaussian mixture model (GMM) and split-and-merge expectation maximization (SMEM) algorithm are applied to segment the image represented by input data. In order to extract the UV pattern from the segmented image, we develop a criterion using the area of covariance vector and the weight value. The experimental results on various paper money are presented to verify the usefulness of the proposed method.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.45-46
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• 2007

• Membrane and Water Treatment
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• v.9 no.6
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• pp.393-403
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• 2018

In this research commercial polyethersulfone (PES) membrane was modified using $TiO_2$ nanoparticles (P-25 Degussa) and further irradiated using UV light to overcome the hydrophobicity and fouling nature of the membrane. Further the membranes were characterized using SEM and FTIR. Contact angle measurements study confirmed the hydrophilic tendency of the modified membrane by decreasing the contact angle from $73^{\circ}$ to $20.28^{\circ}$. The modified membranes showed higher flux and better anti-fouling properties as compared to the unmodified counterparts. The optimum conditions were found to be 0.5 wt% $TiO_2$ loading with 60 min membrane immersion and 10 min UV light illumination. The effect of different pH conditions of feed was analysed. Real wastewater filtration experiments also indicated better performance of modified membranes as opposed to neat PES membranes.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.5
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• pp.379-388
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• 2019

Chlorination and UV illumination are being widely applied to inactivate a number of pathogenic microbials in the environment. Here, we evaluated the inactivation efficiency of individual and combined treatments of chlorination and UV under various aqueous conditions. UV dosage was required higher in waste water than in phosphate buffer to achieve the similar disinfecting efficiency. Free chlorine generated by electrolysis of waste water was abundant enough to inactivate microbials. Based on these, hybrid system composed of sequential treatment of electrolysis-mediated chlorination and UV treatment was developed under waste water conditions. Compared to individual treatments, hybrid system inactivated bacteria (i.e., E. coli and S. typhimurium) and viruses (i.e., MS-2 bacteriophage, rotavirus, and norovirus) more efficiently. The hybrid system also mitigated the photo re-pair of UV-driven DNA damages of target bacteria. The combined results suggested the hybrid system would achieve high inactivation efficiency and safety on various pathogenic microbials in wastewater.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.400-406
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• 2010

Etiolation of plant leaves evoke to be photosynthetically inactive because plant leaves are unable to convert photochlorophyllide to chlorophyllide in the absence of light. In addition, UV-B radiation plays an important role in photomorphogenesis and excessive UV-B radiation decreases photosynthesis and causes to damage to cellular DNA. In the present study, two electrical lights obtained with the ultraviolet lamp and moderate lamp were employed to young plants soybean (Glycine max Merr. var Seoritae). After treatment of different lights, young plants were harvested for the determination of pigment contents and chlorophyll fluorescence. The contents of carotenoids and anthocyanins were significantly enhanced with the excessive UV-B radiation. Excessive UV-B light reduced dramatically photosynthetic efficiency causing an irreversible damage on PSII in comparison to the controls treated under normal illumination. As the treatment of normal illumination after dark treatment, the contents of carotenoids and anthocyanains were not changed in the leaves and photosynthetic ability were retained. Therefore, Seoritae soybean leaves might protect themselves from excessive UV-B radiation with up-regulation of antioxidants.

• Korean Journal of Microbiology
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• v.30 no.5
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• pp.371-376
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• 1992

Plasmid pSL4 of plasmid pKM 101 mutant have high protection effects and mutagenecity for UV and methyl methanesulfonate, The mucA gene and a pan of mucE gene of pKM 101 and pSL4 were sucloned onto lacZ' fusion vector pMC874 and the hybrid plasmids pBH31 and pBH30 were selected. These plsmids were intrduced into $recA^{+}lexA^{-}$, $recA^{-}와lexA^{+}$ strains and determined the activity of $\beta$-galactosidase for UV. In $recA^{+}lexA^{+}$ strain.$\beta$-galactosidase activity of pBH30 included mue region of pSL4 was higher thall pBH31 inclued muc region of pKM 10 I and the tf-galactosidase of two plasmids was not induced in reeA and leeA mutants with or without UV illumination. Without UV illumination. the .$\beta$-galactosidasc of pBH30 was expressed a little higher level than that of pBH3L We suggest that the functional difference of pKM 10l and pSL4 are due to the variety of mue regulatory region. Also. a plasmid pBH 100 earring umuC' -lacZ' gene fusion was constructed in vitro to study the regulation of the umu operon. It was shown that the umu operon is induced by UV and is regulated by the reeA and lexA genes.

• Carbon letters
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• v.11 no.4
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• pp.332-335
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• 2010

The photodegradation of the model compounds Quinol, an aromatic organic compound and Acid blue FFS, an acid dye of chemical class Triphenylmethane was studied by using illumination with UV lamp of light intensity 250W. $TiO_2$ and $TiO_2$ doped with Boron and Nitrogen was used as catalyst. The sol-gel method was followed with titanium isopropoxide as precursor and doping was done using Boron and Nitrogen. In photocatalytic degradation, $TiO_2$ and doped $TiO_2$ dosage, UV illumination time and initial concentration of the compounds were changed and examined in order to determine the optimal experimental conditions. Operational time was optimized for 360 min. The optimum dosage of $TiO_2$ and BN doped $TiO_2$ was obtained to be 2 $mgL^{-1}$ and 2.5 $mgL^{-1}$ respectively. Maximum degradation % for quinol and Blue FFS acid dye was 78 and 95 respectively, at the optimum dosage of BN-doped $TiO_2$ catalyst. It was 10 and 4% higher than when undoped $TiO_2$ catalyst was used.