• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.421-424
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• 2000

We have examined the impedance characteristics and the rate characteristics of LPB. As results, the impedance of LPB decreased with increased pressing rate of electrodes, adding amounts of PVdF and VGCF. And the rate characteristics of LPB increased with the a increase of pressure-rate, PVdF and VGCF contents. The rate characteristics of LPB was improved by pressing of electrode and adding of VGCF content. And specific capacity of anode was increased with adding amounts of PVdF. Higher pressing rate of electrodes, higher adding amounts of PVdF and VGCF was necessitated good rate characteristics for lithium polymer battery.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.510-514
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• 1997

The thin film that is electrically conductive and optically transparent is called conductive transparent thin film. ITO(Indium-Tin Oxide) which is a kind of conductive transparent thin film has been widely used in solar cell, transparent electrical heater, selective optical filter, FDP(Flat Display Panel) such as LCD(Liquid Crystal Display), PDP(Plasma Display Panel) and so on. Especially in PDP, ITO films is used as a transparent electrode in order to maintain discharge and decrease consumption power through the improvement of cell structure. In this study, we prepared ITO by reactive r.f. sputtering with indium-tin(Sn 10wt%) alloy target instead of indium-tin oxide target. The ITO films deposited at low temperature 15$0^{\circ}C$ and 8% $O_2$. Partial pressure showed about 3.6 Ω/$\square$. At the end of firing, the resistance of ITO was decreased, the optical transparence was improved above 90%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05c
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• pp.83-87
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• 2003

Thin films of amorphous carbon (a-C) generally combine high wear resistance with low friction coefficients and a-C films have widespread applications as protective coatings and passivation of electrical circuit and insulating layer. In this work we deposited the amorphous carbon (a-C) films on silicon substrate with a high rate DC magnetron sputtering system. It is obtained parameters on the deposition rate and physical properties of a-C films using a wide range of Ar gas pressure and DC power. The physical properties of the films were analyzed by Nanoindenter and AFM (Atomic Force Microscopy), The electrical properties were investigated by electrical conductivity measurement.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1365-1367
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• 2003

In this paper, element technologies such as soldering. arrangement and lamination processes for photovoltaic module manufacture were examined and described as main processes. Especially solder paste and temperature condition in soldering process, loss factor in arrangement process and process conditions in lamination process are investigated to minimize the electrical loss. As a results, temperature condition in soldering process was found to be critical to contact resistance of electrode and life-time. Productivity of the process decreases dramatically by physical damage during arrangement process. Pressure level and press condition of upper chamber in lamination process were important parameters for the reliability. According to the test result of photovoltaic module, electrical properties dropped about $5{\sim}25%$ after 5 years.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.247-253
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• 2000

We evaluated the electric properties of Bi-2223 jointed tapes processed by both resistive-and superconducting-joint methods. For resistive-joint. filler materials of wood metal Pb/Sn. In and silver paste were used whereas for superconductive-joint lap joint method was used. In the resistive joint tape. critical transport property(CCR) n-value and contact resistance were observed to be in the range of 10-85% 1-8,9. and 0.71x10$\^$-6/-0.13x10$\^$-6/Ω, respectively. depending on their filler materials. Specifically it is believed that the electrical properties of resistive joint tape are significantly related to the resistivity of filler materials. On the other hand the CCR of superconductin joint type was varied 55 to 85% with uniaxial pressure probably due to the irregular microstructure in the transition region.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.411-412
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• 2006

A high nitrogen PM tool steel has shown to have an excellent galling resistance due to the introduction of a high amount of a low friction phase predominantly consisting of VN. Tool making and heat treatment are according to standard procedures. An increase of tool life of more than two times compared to ordinary tool steels is found. Furthermore, the new low friction tool steel shows a potential for sintered parts with higher densities through the applica bility of increased compaction pressure or minimized lubricant amount.

• Journal of the korean Society of Automotive Engineers
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• v.9 no.3
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• pp.85-93
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• 1987

The intake system of 4-cycle, 4-cylinder reciprocating engine is investigated the simple model composed of vessel, duct and throttling part. The numerical calculation based on the simulation is performed for the flow phenomena including heat transfer, friction and bend of duct at each part. In the multi-cylinder engine, the volumetric efficiency is increased a little as the junction location is closed to cylinder at the engine speed having maximum volumetric efficiency. The configuration and dimension of intake system have an influence on the inertia effect by resistance and pressure variation, and the magnitude of that is varied by the engine speed. Thus the volumetric efficiency is correlative to them. The volumetric efficiency is high as the intake valve close is advanced at the low engine speed, and is delayed at high speed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1417-1422
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• 2014

Using a parallel plate DC plasma system was prepared. Using this equipment, we investigated the basic discharge characteristics of DC argon plasma in terms of electron density, temperature, voltage and current waveforms and plasma potential. The effects of the electrode gap distance, input voltage, ballast resistance and pressure were measured using electrostatic probe. Plasma simulation using fluid approximation has been performed. External circuit effects was included in the simulation. Measured and calculated current voltage characteristics show similar tendencies.

• Journal of the Korean Society of Safety
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• v.26 no.4
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• pp.65-68
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• 2011

High strength concrete(HSC) has been mainly used in large SOC structures. HSC have superior property as well as improvement in durability compared with normal strength concrete. In spite of durability of HSC, explosive spalling in concrete front surface near the source of fire occurs serious problem in structural safety. It is reported that spalling is caused by the vapor pressure under fire and polypropylene(PP) fiber has an important role in protecting from spalling. The spalling properties of ultra high strength concrete specimens with various contents of PP fiber were investigated in this study. In results, the content of PP fiber for spalling protection increases over 0.2 vol.% as the concrete strength increases to 120 MPa.

• Journal of the Korean institute of surface engineering
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• v.34 no.1
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• pp.25-32
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• 2001

$TiB_2$ ceramics were oxidized at 800, 900 and $1000^{\circ}C$ in air for 40 hr, and their oxidation property was investigated using TGA, XRD, SEM and EPMA. The oxidation resistance decreased with an increase in oxidation temperature. The scale was essentially composed of $TiO_2$ only. $B_2$$O_3$ formed during oxidation escaped from the $TiO_2$ oxide scale owing to its high vapor pressure. This made the oxide scale highly porous and thick. The oxidation reaction was mainly governed by the inward transport of oxygen.$ TiO_2$ existing at the outermost scale grew into peculiarly shaped blades, as the reaction progressed.