• Journal of Korean Society on Water Environment
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• v.26 no.4
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• pp.707-712
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• 2010

Nitrogen-doped $TiO_2$ particles have been successfully prepared using titanium tetraisopropoxide as the Ti source and urea as the nitrogen source. As-prepared nitrogen-doped $TiO_2$ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller method (BET) and ultraviolet-visible light (UV-vis) absorption spectra techniques. Photocatalytic degradation of Methylene Blue (MB) has been carried out in both solar light (UV-vis) and the visible region (${\lambda}=420nm$). Nitrogen-doped $TiO_2$ exhibits higher activity than the commercial $TiO_2$ photocalyst, particularly under visible-light irradiation because bandgap of nitrogen-doped $TiO_2$ becomes remarkably decreased.

• Journal of Pharmaceutical Investigation
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• v.24 no.1
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• pp.29-32
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• 1994

In order to improve the sensitivity of the current assay methods of selenium in dried-yeast preparations, atomic absorption spectrophotometry (AAS), high performance liquid chromatography (HPLC) and UV-Vis spectrophotometry were employed. The sample was prepared with the digestion by acid mixture of hydrochloric acid, nitric acid and perchloric acid after elimination of ether-soluble substances. The range of quantitation of selenium was $1.0{\sim}6.0\;{\mu}g/ml$ by UV-Vis spectrophotometry, $5.0{\sim}20.0\;{\mu}g/ml$ by HPLC and $0.03{\sim}0.10\;{\mu}g/ml$ by AAS.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.8
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• pp.62-68
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• 1998

Optical broadband second harmonic genration (SHG) in thin film waveguide structure was investigated. The copolymer poly(MMA-co-DR1MA) which was consiste dof PMMA (polymethylmethacrylate) and DR 1 (disperse red 1) was spin coated on the pyrex substrate. The green and near UV SHG were observe dfrom the fundamental beam even though the poled polymer has the absorption in second harmonic wavelength range. It was able to genrate SHG by cerenkov type phase matching. Th epoled polymer film thickness was decided by theoretical analysis. The green (532nm) and near UV SHG (370nm) were observed from the Q-switched Nd-YAG laser (1064nm) and Ti-sapphire laser (740nm). It was in good agreement with the experimental results.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.218-218
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• 1996

Brazilin은 포도당 수송을 증가시키는 물질로 autooxidation에 의하여 산화되면서 hydrogen peroxide를 생성할 것으로 추정되었으며, hydrogen peroxide는 phosphatase를 억제하여 포도당 수송을 증가시키는 것으로 보고되었다. 따라서 본 실험에서 brazilin의 산화에 의한 hydrogen peroxide의 생성여부를 확인하고 phosphatase 활성에 미치는 braziline의 작용을 살펴보았다. 먼저 UV absorption spectra를 이용하여 brazilin이 반응액중에서 구조적인 변화를 일으키는지 확인하였다. Hydrogen peroxide의 생성은 rhodamine 123를 이용한 형광측정법으로 측정하였으며, phosphatase의 활성은 pH에 따른 phosphatase의 활성을 p-NPP의 탈인산화의 UV 흡광도 변화로 측정하였다. PP2A의 활성은 phosphorylase a를 기질로 하여 측정하였다.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.47.2-47.2
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• 2014

Bulges of galaxies are thought to have formed and grown at least in part through galaxy mergers, and thus an accurate derivation of their properties can be an effective course to test/confirm our understanding on their formation and evolution in the standard hierarchical merger paradigm. We have generated a sample of galaxy bulges (n = 15,423) in the nearby (0.005 < z < 0.05) universe from the SDSS DR7 and GALEX GR6plus7 databases and derived their structural and photometric properties by means of SExtractor and GALFIT application. Most notable properties include bulge-to-total luminosity ratio, effective radius, disk scale length, ellipticity, and position angle. The UV properties of the bulges have also been analyzed to infer their recent star formation history. A spectroscopic analysis has been performed using their absorption and emission line strengths measured and released by the OSSY team. We present our preliminary results from our investigation mainly focused on stellar population properties and discuss their implications on the formation of bulges.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.132-136
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• 2004

열 증착 방법을 이용하여 copper(II)-phthalocyanine(CuPc) 박막을 glass 기판 위에 제작하였다. 열처리 조건은 $150^{\circ}C$에서 후열(annealing) 처리 하는 방식과 예열하는 두 가지 방식으로 달리하였다. 제작된 박막의 전기전도도를 평가하기 위해 마이크로웨이브 근접장 효과를 이용한 근접장 현미경(near-field scanning microwave microscope)을 이용하여 비파괴적인 방식으로 CuPc 박막의 반사계수(reflection coefficient)를 측정하였다. CuPc 박막의 전기전도도 특성을 UV 흡수도를 통한 에너지 밴드갭의 shift 현상과 관련지어 설명하고 또한 x-ray diffraction(XRD) data를 통해 박막의 결정 특성과 비교하였다. 박막 표면 특성은 SEM(scanning microscope microscopy)을 통해 관측하였다. 열처리 조건에 따른 CuPc 박막의 전기전도도 특성은 후열 처리한 박막의 경우 예열 처리한 박막보다 전기 전도 특성이 향상되었음을 관측할 수 있었다.

• Korean Journal Plant Pathology
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• v.13 no.1
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• pp.63-68
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• 1997

In the screening of antiviral materials produced by actinomycetes, an isolate named B25 was fond to produce an antibiotic substance ASA, which showed a strong inhibitory activity against tobacco mosaic virus (TMV) infection. ASA was purified from culture broth of B25 by silica gel column chromatography, preparative TLC, and reversed phase HPLC. Also MS, IR, UV spectrum, and melting point of ASA were determined and analysed. ASA was white powder soluble in dimethyl sulfoxide, chloroform, and ethyl acetate, having absorption peaks at 223 and 328 nm in UV-VIS spectrum, and had a molecular weight of 548. ASA showed strong inhibitory effect on TMV infection when it was applied as a mixture of TMV to the upper surface of leaves of a local lesion host (Nicotiana tabacum c. Xanthi-nc). It also showed antimicrobial effect against yeast and some phytopathogenic fungi.

• Bulletin of the Korean Chemical Society
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• v.31 no.9
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• pp.2575-2580
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• 2010

We present a method for chemically reducing silver alkylcarbamate complex with hydrazine to synthesize silver nanocolloids in an organic solvent using polyvinylpyrrolidone (PVP) as the stabilizer. To determine the optimal conditions for preparing stable silver colloids of controlled size and shape, the silver 2-ethylhexylcarbamate (Ag-EHCB) complex, PVP, hydrazine, and 2-propanol solvent concentrations in the reaction mixture were varied. The initial colloid has a mean particle diameter of 5-80 nm, and it exhibits an absorption band with various shapes in the UV region with a maximum near 420 nm. UV-vis spectroscopy, TEM, and X-ray diffraction techniques were used to investigate the formation and growth process of the metallic silver nanocolloids.

• Journal of the Korean Applied Science and Technology
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• v.11 no.2
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• pp.147-150
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• 1994

Ultra thin films of HDSM-CuPc(Tetra-3-hexadecylsulphamoylcopperphthalocya-nine) were formed on various substrates by Langmuir-Blodgett method, where HDSM-CuPc was synthesized by attaching long-chain alkylamine(hexa-decylamine) to CuPc. The reaction product was identified with FT- IR, UV-visible absorption spectroscopies, elemental analysis and thin layer chromatography. The formation of ultrathin films of HDSM-CuPc was confirmed by FT-IR and UV-visible spectroscpies.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.424.2-424.2
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• 2014

Ag-modified BiOX (X=Cl, Br and I) nanoplates were synthesized by an ion-exchange reaction. We examined the fundamental properties by scanning electron microscopy (SEM), electron transmission microscopy (TEM), X-ray diffraction, UV-visible absorption, Fourier-transform infrared and photoluminescence spectroscopy. The adsorption and photocatalytic performances of the catalysts were tested with dyes under UV and visible light. A chemical scavenger method was employed to test the roles of active species (${\cdot}OH$, ${\cdot}O2-$ and h+) and understand photodegradation mechanism. Photoluminescence spectroscopy was used to examine ${\cdot}OH$ radical formation using terephthalic acid during photoirradiation.