• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.212-216
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• 2000

ZnO varistors for distribution surge arrester (18kV, 5kA) were developed and tested microstructure and electrical characteristics. Microstructure of ZnO varistor was consisted of ZnO grain, spinel phase and Bi-rich phase. Average grain size of ZnO varistor was $\mu\textrm{m}$ Reference voltage and lightning impulse residual voltage of ZnO varistor exhibited a good haracteristics above 5.5kV and below 11.56kV, respectively. Consequently, discharge capacity which is the most important characteristics of ZnO varistor for surge arrester exhibited excellent properties above 70kA at twice high-current impulse test. Moreover, variation rate of reference voltage and lightning impulse residual voltage showed below 5% and 2% after high-current impulse test, respectively. Leakage current and watt loss of ZnO varistor will not increase during accelerated aging test at stress condition, such as 3.213kV/$115^{\circ}C$/1000h.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.600-603
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• 2007

The effect of a water-miscible ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate $([BMIM][BF_4])$, on the horseradish peroxidase (HRP)-catalyzed oxidation of 2-methoxyphenol (guaiacol) with hydrogen peroxide $(H_2O_2)$ was investigated. HRP maintains its high activity in the aqueous mixtures containing various concentrations of the ionic liquid and even in 90% (v/v) ionic liquid. In order to minimize the effect of solution viscosity on the kinetic constants of HRP catalysis, the enzymatic reactions in the subsequent kinetic study were performed in water-ionic liquid mixtures containing 25% (v/v) ionic liquid at maximum. As the concentration of $[BMIM][BF_4]$ increased for the oxidation of guaiacol by HRP, the $K_m$ value increased with a slight decrease in the $K_{cat}$ value: The $K_m$ value increased from 2.8 mM in 100% (v/v) water to 22.5mM in 25% (v/v) ionic liquid, indicating that ionic liquid significantly weakens the binding affinity of guaiacol to HRP.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.29-32
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• 2008

최근 PDP Display 시장은 해를 거듭 할수록 가격 경쟁이 치열해 지고 있다. 그에 따라 PSU(Power Supply Unit) 모듈의 저 가격화 및 경량화가 요구되고 있고, 요구조건을 만족하기 위해 여러 출력을 하나로 통합화 하는 다 출력 구조의 변압기가 적용되고 있다. 본 논문에서는 서스테인 전원부($V_s$)와 어드레스 전원부($V_a$), 그리고 Multi 18V전원부($V_m$)를 하나의 변압기에 일체화 하였다. 그리고 어드레스 전원부($V_a$)와 Multi 18V전원부($V_m$)의 부하 추가에 따라 서스테인 전원부($V_s$)의 전압 이득 특성 및 공진특성 변화를 확인하였다. 또한 다 출력 LLC 직렬공진 컨버터 설계 시 고려사항과 동작 특성으로 42인치 HD PDP 전원에 적용하여 검증한 결과에 대하여 서술 하였다.

• Journal of the Korean Chemical Society
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• v.29 no.4
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• pp.372-381
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• 1985

Oxo molybdenum (V) complexes of substituted 8-quinolinols were synthesized and characterized by means of the investigation of elemental analysis, infrared spectra, electron spectra, electric conductivity and mass spectrometry compared with oxo molybdenum (VI) complexes. Oxo molybdenum(V) complexes were nonelectrolyte and one strong band of stretching mode of molybdenum and terminal oxygen appeared approximately $940cm^{-1}$. Oxo molybdenum(VI) complexes gave two peaks corresponding molybdenum containing ions, a molecular ion (I) of a 2 : 1 (ligand : metal) chelate and a fragment ion (II) of a 1:1 chelate due to the loss of ligand radical from ion (I). Molybdenum(V) complexes were observed the fragment ion(II) of a 1 : 1 chelate partly. The electronic spectra corresponding to d-d transition and charge transfer transition were observed and interpreted.

• Bulletin of the Korean Mathematical Society
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• v.53 no.6
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• pp.1613-1615
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• 2016

It is proved that $k[X_1,{\ldots},X_v ]$ localized at the ideal ($X_1,{\ldots},X_v$ ), where k is a field and $X_1,{\ldots},X_v$ indeterminates, is not weakly quasi-complete for $v{\geq}2$, thus proving a conjecture of D. D. Anderson and solving a problem from "Open Problems in Commutative Ring Theory" by Cahen, Fontana, Frisch, and Glaz.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.459-462
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• 2006

In this paper, we proposed a novel TFT-LCD pixel structure to compensate ${\Delta}V_p$, which is a maximum value of 1.82V in conventional pixel structure without compensation. We achieved a maximum value of 60mV in proposed pixel structure by integrating a dummy switch TFT in each pixel. The proposed TFT-LCD pixel structure with a remarkably reduced ${\Delta}V_p$ allows ultra high picture quality AMLCDs.

• Korean Chemical Engineering Research
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• v.47 no.3
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• pp.275-280
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• 2009

The direct incorporation of vanadium into the three-dimensional(3-D) cubic Ia3d mesostructure designated as V-KIT-6 was carried out hydrothermally using a Pluronic P123 and n-butanol as the structure-directing mixture, tetraethylorthosilicate(TEOS) as the silica source and $NH_4VO_3$ as the vanadium source. The obtained V-KIT-6 showed a very high specific surface area ${\sim}1,000m^2/g$ with tunable pore diameters in narrow distribution of sizes ~6.0 nm. The coordination and nature of V sites in V-KIT-6 are characterized by $^{51}V$-spin-echo NMR analysis. The calcined V-KIT-6 materials showed excellent catalytic activity in the direct oxidation of styrene using tert-butyl hydroperoxide(TBHP) as an oxidant.

• Korean Journal of Materials Research
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• v.16 no.3
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• pp.178-182
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• 2006

A single electro-discharge-sintering (EDS) pulse (1.0 kJ/0.7 g), from a $300{\mu}F$ capacitor, was applied to atomized spherical Ti-6Al-4V powder in a low vacuum to produce porous-surfaced implant compacts. A solid core surrounded by a porous layer was formed by a discharge in the middle of the compact. XPS (X-ray photoelectron spectroscopy) was used to study the surface characteristics of the implant material. C, O, and Ti were the main constituents, with smaller amounts of Al, V, and N. The implant surface was lightly oxidized and was primarily in the form of $TiO_2$ with a small amount of metallic Ti. A lightly etched EDS implant sample showed the surface form of metallic Ti, indicating that EDS breaks down the oxide film of the as-received Ti-6Al-4V powder during the discharge process. The EDS Ti-6Al-4V implant surface also contained small amounts of aluminum oxide in addition to $TiO_2$. However, V detected in the EDS Ti-6Al-4V implant surface, did not contribute to the formation of the oxide film..

• Applied Chemistry for Engineering
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• v.31 no.5
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• pp.560-567
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• 2020

In this study, we investigated that the effect of alkali metals [Na(Sodium) and K(Potassium)], known as representative deactivating substances among exhaust gases of various industrial processes, on the NH₃-SCR (selective catalytic reduction) reaction of V/W/TiO₂ catalysts. NO, NH₃-TPD (temperature programmed desorption), DRIFT (diffuse reflectance infrared fourier transform spectroscopy analysis), and H₂-TPR analysis were performed to determine the cause of the decrease in activity. As a result, each alkali metal acts as a catalyst poisoning, reducing the amount of NH₃ adsorption, and Na and K reduce the SCR reaction by reducing the L and B acid points that contribute to the reaction activity of the catalyst. Through the H₂-TPR analysis, the alkali metal is considered to be the cause of the decrease in activity because the reduction temperature rises to a high temperature by affecting the reduction temperature of V-O-V (bridge oxygen bond) and V=O (terminal bond).

• Korean Journal of Mathematics
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• v.23 no.4
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• pp.607-618
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• 2015

An L(2; 1)-labeling of a graph G is a function f from the vertex set V (G) to the set of all non-negative integers such that ${\mid}f(u)-f(v){\mid}{\geq}2$ if d(u, v) = 1 and ${\mid}f(u)-f(v){\mid}{\geq}1$ if d(u, v) = 2. The ${\lambda}$-number of G, denoted ${\lambda}(G)$, is the smallest number k such that G admits an L(2, 1)-labeling with $k=\max\{f(u){\mid}u{\in}V(G)\}$. In this paper, we consider the square of a cycle and provide exact value for its ${\lambda}$-number. In addition, we also completely determine its edge span.