• Transactions on Electrical and Electronic Materials
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• 제11권1호
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• pp.1-10
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• 2010

This is an overview paper reporting our most recent work on processing and microstructure of nano-structured oxides and their photoluminescence and photo-catalysis properties. Zinc oxide and related transition metal oxides such as vanadium pentoxide and titanium dioxide were produced by a combination of magnetron sputtering, hydrothermal growth and atmosphere controlled heat treatment. Special morphology and microstructure were created including nanorods arrays, core-brushes, nano-lollipops and multilayers with very large surface area. These structures showed special properties such as much enhanced photoluminescence and chemical reactivity. The photo-catalytic properties have also been promoted significantly. It is believed that two factors contributed to the high reactivity: the large surface area and the interaction between different oxides. The transition metal oxides with different band gaps have much enhanced photoluminescence under laser stimulation. Use of these complex oxide structures as electrodes can also improve the energy conversion efficiency of solar cells. The mixed oxide complex may provide a promising way to high-efficiency photo emitting materials and photo-catalysts.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.68-68
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• 2018

Nanoporous or nanotubular metal oxide can be fabricated by anodization of metal substrate in fluoride contained electrolytes. The approach allows various transition metals such as Zr, Hf, Nb, Ta to form highly ordered oxide nanostructures. These oxide nanostructures have various advantages such as high surface area, fast electron transport rate and slow recombination in semiconductive materials. Recently, vanadium oxide nanostructures have been drawn attentions due to their superior electronic, catalytic and ion insertion properties. However, anodization of vanadium metal to form oxide layers is relatively difficult due to ease formation of highly soluble complex in water contained electrolyte during anodization. Yang et al. reported $[TiF_6]^{2-}$ or $[BF_4]^-$ in electrolyte helps to formation of stable oxide layer [1, 2]. However, the reported approaches are very sensitive in other parameters. In this presentation, we deal with the other important key parameters to form ordered anodic vanadium oxide such as pH, temperatures and applied potential.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 추계학술대회논문집
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• pp.93-96
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• 2000

In this study, we investigated the electromagnetic properties of Mn-Zn ferrite doped with rare earth oxide (Dy$_2$O$_3$, Er$_2$O$_3$). The main composition is 52mo1% $\alpha$-Fe$_2$O$_3$, 25mo1% Mn$_3$O$_4$23mo1% ZnO and doped with them(0.05wt%~0.25wt%, step:0.05wt%). An experimental process has advanced by conventional ferrimagnetism manufacturing that was prepared by standard ceramic techniques. The XRD pattern of all doped sample were observed spinel and secondary phase. The density of sample were measured nearly constant value. As increased the additive, resistivity, initial permeability and real component of the series complex permeability increased with setting limits each other. In case of Mn-Zn ferrite excess doped with them, resistivity, initial permeability and real component of the series complex permeability decreased and magnetic loss increased in proportion to increasing the additive.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.93-96
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• 2000

In this study, we investigated the electromagnetic properties of Mn-Zn ferrite doped with rare earth oxide (Dy$_2$O$_3$, Er$_2$O$_3$). The main composition is 52mo1% ${\alpha}$-Fe$_2$O$_3$, 25mol% Mn$_3$O$_4$ 23mo1% ZnO and doped with them(0.05wt% ∼ 0.25wt%, step:0.05wt%). An experimental process has advanced by conventional ferrimagnetism manufacturing that was prepared by standard ceramic techniques. The XRD pattern of all doped sample were observed spinel and secondary phase. The density of sample were measured nearly constant value. As increased the additive, resistivity, initial permeability and real component of the series complex permeability increased with setting limits each other. In case of Mn-Zn ferrite excess doped with them, resistivity, initial permeability and real component of the series complex permeability decreased and magnetic loss increased in proportion to increasing the additive.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.654-655
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• 2006

This is about the effects deoxidization, carbonization and alloying preparation on fine grain W, WC, and grade YG8 powder reduced by "yellow tungsten oxide" and "blue tungsten oxide". The result indicates that yellow tungsten has single composition and blue tungsten oxide has complex composition. With this feature, yellow tungsten oxide got better uniformity and concentration distribution on fine particle size W and WC powder than blue tungsten oxide's. The grade alloy YG8 that made of this W or WC powder has uniform alloy construction, concentrated WC grain distribution and better alloy properties.

• 한국세라믹학회지
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• 제44권12호
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• pp.660-682
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• 2007

An SOFC consists of all ceramic complex oxides each with different electrochemical-property requirements. These requirements, in principle, can be made met to a great extent by controlling or tailoring the defect structure of the oxide. This paper reviews the defect structure, nonstoichiometry as a measure of the total defect concentration, and the defect relaxation kinetics of complex oxides that are currently involved in a variety of growing applications today.

• 한국표면공학회지
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• 제49권2호
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• pp.130-134
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• 2016

The anodization of ADC12 aluminum alloy was investigated in the metal anionic acid media. Anodic oxide films containing foreign elements were formed on ADC12 Al alloy by anodization in the anion complex solution. Furthermore, the rough surface and cracks were considerably smoothened by the deposit of metal anions. When the size of metal anion was small, relatively large amount of metal anions was loaded in anodic films. Existence of $MoO_3$, $TiO_2$ and MgO was confirmed by XPS. According to the results of Tafel analysis, Mo oxide represented the most noble anti-corrosion potential due to $MoS_2$ formation. Corrosion current densities were generally higher than that of pristine anodic oxide without anion complexes.

• 한국응용과학기술학회지
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• 제35권2호
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• pp.325-335
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• 2018

본 연구는 화장품 소재로서 인삼복합물의 가능성을 확인하기 위한 것이다. 이를 위해 우리는 인삼복합물 에탄올 추출물을 사용하여 항염증, 미백 효과에 대한 생물학적 활성 평가를 수행하였다. 시료는 인삼(A), 상황(B), 리기다소나무(C)를 각 70% 에탄올로 추출한 후 (A)1 : (B)1 : (C)0.5의 비율로 혼합한 시료를 사용하였다. 대식세포(RAW 264.7 cells)내에서 시료의 항염증 효과를 평가하기 위해 MTT assay를 이용한 샘플의 독성평가와 nitric oxide 생성 저해 활성 및 염증관련 단백질 및 유전자의 발현량을 확인하였다. 시료의 미백 효과를 평가하기 위해서 멜라노마(B16F10 cell)를 이용해 MTT assay를 통한 샘플의 독성평가, cellular tyrosinase 저해율 측정 및 멜라닌 생합성량을 측정하였다. LPS로 유도된 RAW 264.7 세포내에서 시료의 nitric oxide 저해 활성 결과는 $25{\mu}g/mL$ 농도에서 71.2%의 우수한 효능을 나타내었으며 western blot 실험결과 iNOS, COX-2 단백질의 발현은 농도 의존적으로 감소하는 것을 확인하였다. Tyrosinase 활성 억제 실험에서 인삼복합물의 농도 $50{\mu}g/mL$에서 36.8%의 감소를 나타냈으며 멜라닌 생합성 억제 평가 결과에서 농도 $50{\mu}g/mL$에서 47.8%의 감소를 나타냈다. 상기 실험 결과로부터 인삼복합물의 우수한 항염증, 미백 효능을 확인하였으며 향후 안전한 천연 화장품 원료로 사용될 수 있음을 확인하였다.

• 대한화학회지
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• 제39권11호
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• pp.837-841
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• 1995

사염화탄소 속에서 티오프로피온아미드(TPA)와 triethylphosphine oxide(TEPO), triethylphosphine oxide(TPPO), trimethylphosphate(TMP), 그리고 tributyl phosphate(TBP)간의 수소 결합에 대한 열역학적 상수들을 근적외선 분광법을 이용하여 구하였다. TPA의 .nu./.alpha./+amide 2 조합띠는 TPA 단위체 및 수소 결합을 이룬 TPA의 띠로 이루어져 있음이 확인되어 이 띠를 두 개의 Lorentzian-Gaussian 곱함수의 띠로 분해하였다. 온도 및 농도의 변화에 따른 이 조합띠의 변화기로부터 TPA와 TEPO, TPPO, TMP, TBP의 수소 결합 엔탈피는 각각 -21.4, -16.8, -12.8, -12.9kJ/mol이었다. 이 결과는 치환기의 inductive effect 및 steric effect로 설명할 수 있다.

• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.796-798
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• 1997