• 한국전기전자재료학회논문지
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• 제14권8호
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• pp.652-657
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• 2001

Vanadate glasses containing 10~20mol% glass former, P$_2$O$_{5}$ were prepared by melting the batch in platinum crucible and quenching on the copper plate. Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics having LiV$_3$O$_{8}$ were obtained by heat-treatment of this glass in crystallization temperature. The glass-ceramics showed singnificantly good capacity and long cycles life according to heating condition. In this paper, we described electrochemical properties during crystallization process and found the best crystallizaton condition of Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass as cathode material. Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics heat-treated at 233$^{\circ}C$ for 3 hors showed good rechargeable capacity of 220mAh/g in the cycling range between 2.0 and 3.9V.en 2.0 and 3.9V.

• Environmental Engineering Research
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• 제24권4호
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• pp.646-653
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• 2019

Recovery of valuable metals in the industrial wastewater and sludge has attracted an attention owing to limited metallic resources in the earth. In this study, we firstly fabricated Ti/Ir-Ru electrodes by spin coating technique for effective recovery of Cu in electrowinning process. Two different Ti/Ir-Ru electrodes were fabricated using 100 and 500 mM of precursors (i.e., Ir-Ru). SEM-EDX and AFM revealed that Ir and Ru were homogenously distributed on the surface of Ti plate by the spin coating, in particular the electrode prepared by 500 mM showed distinct boundary line between Ir-Ru layer and Ti substrate. XRD, XPS, and cyclic voltammetry also revealed that characteristics of IrO₂, RuO₂, and TiO₂ and its electrocatalytic property increased as the concentration of coating precursor increased. Finally, we carried out Cu recovery experiments using two Ti/Ir-Ru as anodes in electrowinning process, showing that both anodes showed a complete removal of Cu (1 and 10 g/L) within 6 h reaction, but much higher kinetic rate constant was obtained by the anode prepared by 500 mM. The findings in this study can provide a fundamental knowledge for surface characteristics of Ti/Ir-Ru electrode prepared by spin coating method and its potential feasibility for effective electrowinning process.

• 한국인터넷방송통신학회논문지
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• 제13권5호
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• pp.221-227
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• 2013

본 논문에서는 모바일 서비스를 위한 실내 중계기용 위성 DMB/WiBro 대역 안테나 및 PCS/WiBro 대역 안테나를 설계 및 제작하였다. 제안한 위성 DMB/WiBro 대역 중계기 안테나 및 PCS/WiBro 대역 중계기 안테나는 좌선편파를 산출할 수 있는 용량을 구성한 단순한 방사기로 제안되었다. 제안된 안테나는 위성 DMB/WiBro 대역과 PCS/WiBro 대역에서 동작하도록 동판거치형과 기판거치형으로 설계 및 제작하였다. 설계된 안테나는 1.816GHz ~ 1.886GHz, 2.247GHz ~ 2.354GHz 대역에서 70MHz, 107MHz의 대역폭을 갖으며, 방사패턴의 최대 이득이 5dBi 이상임을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.144-146
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• 1995

A superconducting 2 tesla MRI magnet for the animal magnetic resonance imaging has been developed as a basic model for the application of the precise supercoducting magnet technology. MRI cryostat with 210mm room temperature bore was designed and manufactured for this magnet. The cryostat was designed basically not only to extract the principal design parameters at the performance test but also for the convenience of the manufacturing. The most extinct feacture of the cryostat is that it does not have $LN_{2}$ tank and the 77K thermal shield is cooled by circuling $LN_{2}$ through copper pipe which is welded around the shield plate. It results in reduction of the total cryostat size(about 30%).

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.550-553
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• 2001

Li$_2$O-P$_2$O$_{5}$-Bi$_2$O$_3$-V$_2$O$_{5}$ glass containing glass former, P$_2$O$_{5}$ and Bi$_2$O$_3$ was prepard by melting the glass batch in pt. erucible followed by quenching on the copper plate. We found that Li$_2$O-P$_2$O$_{5}$-Bi$_2$O$_3$-V$_2$O$_{5}$ g1ass-ceramics obtained from the crystallization of glass showed significantly higher capacity and longer cycle life tham LiV$_3$O$_{8}$ made from powder synthesis. In this paper, we described crystallization process and LiV$_3$O$_{8}$ crystal growth in glass matrix by increasing temperature. The electrochemical properties were strongly affected by LiV$_3$O$_{8}$ crystal growth in matrix.rowth in matrix.

• 한국의류학회지
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• 제15권4호
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• pp.373-380
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• 1991

In the previous paper, we already discussed about the factor effected upon the initial maximum value of heat flux ($q_{max}$). Thermal conductivity, thermal transmittance and surface air cavity of wool fabrics were examind and their correlation to the $q_{max}$ was also studied In this study, the other factor was examined which had on effect upon the qmaf of an objective measure of warm/cool feeling. It was studied that the qmax correlated to the surface sturucture parameters (compression, friction, smoothness, roughness, thickness and weight). It was concerned to the degree of warm/cool feeling when we touched hand on fabrics. We selected twenty sorts of pure wool woven fabrics for men's fall-winter cloth (all Wool). The conclusions are as follow; 1. There was a good correlation between the $q_{max}$ and the compression property. 2. The surface structure parameters, smoothness and roughness, made various effects on the $q_{max}$, when the samples touched on a thin copper plate. So, there was not a certain correla-tion to the $q_{max}$.

• 조명전기설비학회논문지
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• 제27권9호
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• pp.1-5
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• 2013

We developed high-efficient 6W-LED package with simple structure by applying Heat Slug and silicone-reflector. LED package was manufactured in $8.5{\times}8.5mm$ sized multi-chip structure having thickness of $500{\mu}m$ achieved by bonding silicon-reflector with prepreg on top of the plate after implementing the reflector placed on copper substrate Half Etching by thickness of $200{\mu}m$. The luminous flux, luminous efficacy, correlated color temperature, color rendering index and thermal resistance of developed LED was evaluated, and it verified the application of products by applying it to 120W-LED road luminaires through simulation. The luminous efficacy of LED package reached over 130lm/W, and it is possible to be manufactured into 120W-LED road luminaires using 18 packages. In addition, the simulation results showed average of horizontal illuminance and overall illuminance uniformity that is suitable for three-lane road.

• 전기학회논문지
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• 제58권11호
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• pp.2128-2135
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• 2009

In this paper, current limiter using a magnetic switching which is based on magnetic flux change in the case of fault is proposed. This current limiter consists of iron-core and three parts of coils. One is the primary coil connected to the power system. Another is the secondary coil wound to the opposite direction of the primary coil's winding. The other is the secondary of the secondary coil which is a movable copper plate winding and located below the secondary coil. In the normal state, the magnetic flux produced in the primary and secondary coils flows to the opposite directions each other and becomes to be canceled out. Therefore the voltages induced between the coils are zero. In the case of a fault, at the moment of a fault occurrence recognition, the switch connected to a secondary coil is opened and the secondary of the secondary coil is pulled out to the outside of the iron-core. Then, magnetic flux becomes to flow through the iron-core. Accordingly, the voltage is induced between the both ends of the primary coil and makes the current reduced. Therefore it is possible to cut off the circuit breaker easily with the proposed current limiter. This paper analyzes the current limiting effects and the detailed results are given.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.523-527
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• 2000

Vanadate glasses in the Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ system containing 10mo1% glass former, P$_2$O$_{5}$ were prepared by melting the batch in pt. crucib1e followed by quenching on the copper plate. We found that Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics obtained from nucleation of glass showed significantly higher capacity and longer cycle life than conventionally made crystalline LiCoO$_2$, LiNiO$_2$and LiV$_3$O$_{8}$. In the present paper, We describe electro-chemical properties during crystallization process and find the best crystallization condition of Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ g1ass as cathod material. Li$_2$O-P$_2$O$_{5}$-V$_2$O$_{5}$ glass-ceramics shows superior rechargeable capacity of 220 mAh/g in the cycling between 2.0 and 3.9V.etween 2.0 and 3.9V.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.334-335
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• 2005

Ternary tellurite glassy systems ($Li_2O-V_2O_5-P_2O_5$) have been synthesised using Vanadium oxide as a network former and Lithium oxide as network modifier. The addition of a metal? oxide makes them electric or mixed electric-ionic conductors, which are of potential interest as cathode' materials for solid-state batteries. This glass-ceramics crystallized from the $Li_2O-V_2O_5-P_2O_5$ system are particularly interesting, because they exhibit high conductivity (up to $5.95\times10^{-4}$ S/cm) at room temperature. the glass samples were prepared by quenching the melt on the copper plate and the glass-ceramics were heat-treated at crystallizing temperature determined from differential thermal analysis (DTA). The electric D.C conductivity result have been analyzed in terms of a small polaron-hopping model.