• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.454-459
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• 2013

Recently, remote phosphors have been reported for application to white LEDs to provide enhanced phosphor efficiency compared with conventional phosphor-based white LEDs. In this study, a remote phosphor was produced by coating via screen printing on a glass substrate with different numbers of phosphor coating. The paste consists of phosphor, lowest softening glass frits, and organic binders. The remote phosphor could be well controlled by varying the phosphor content rated paste. After mounting the remote phosphor on top of a blue LED chip, CCT, CRI, and luminance efficiency were measured and values of 5300 K, 62, and 117 lm/W were respectively obtained in the 80 wt% phosphor with 3 coating layers sintered at $800^{\circ}C$.

• Resources Recycling
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• v.26 no.6
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• pp.97-101
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• 2017

Metal foams have a cellular structure consisting of a solid metal containing a large volume fraction of pores. In particular, open pores which are penetrable pores are necessary for industrial applications such as in high temperature filters and as support for catalysts. In this study, Fe foam with greater than 90% porosity and 2-mm pore size was successfully fabricated using a slurry coating process and the pore properties were characterized. The Fe and $Fe_2O_3$ powder mixing ratios were controlled to produce Fe foam samples with different pore sizes and porosity. First, the slurry was prepared through the uniform mixing of powders, distilled water, and polyvinyl alcohol(PVA). The amount of slurry coated with the PU foam increased with increasing $Fe_2O_3$ mixing powder ratio, but the shrinkage and porosity of the Fe foams decreased, respectively, with increasing $Fe_2O_3$ mixing powder ratio.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.161-165
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• 2005

Recently, it is on the increase interest for Al alloy with new material for ship application to substitute for FRP ship. The reason is thatAl alloy ship has beneficial characteristics such as high sea speed, increase of loadage and easy to recycle compared with FRP ship. In this paper, mechanical and electrochemical properties are investigated by slow strain rate test experiment in various applied potential condition. These results will provide as reference data to design ship by deciding optimum protection potential regard to hydrogen embrittlement and stress corrosion cracking. In general, Al and Al alloys are not corroded with forming film which has the corrosion resistance property in neutral solution. However, it was observed that formation and destruction of passive film by $Cl^-$ ion in sea water environment. At comparison of current density after 1200 sec in potentiostatic experiment, the current density in the potential range of -0.68 $\~$-1.5 V is shown low value. The low current density means protection potential range. Elongation in applied potential of 0 V was high. However, the corrosion protection application in this condition is impossible potential because the toughness is low value by decreasing strength by active dissolution reaction at parallel part of specimen. The film composed with $CaCO_3$ and $Mg(OH)_2$ has a corrosion resistance property. However, the uniform electrodeposition coating at below -1.6 V potential is not formed since the time to form the uniform electrodeposition coating is short. Therefore, it is concluded that mechanical property is poor because effect by hydrogen gas generation is larger than that of electrodeposition coating. It is concluded that the optimum protection potential range from comparison of_maxim urn tensile strength, elongation and time to fracture is -1.3$\~$0.7 V (SSCE).

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.1
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• pp.40-47
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• 2014

In this paper, $Al_2O_3$ film deposited by thermal atomic layer deposition (ALD) with diluted $NH_4OH$ instead of $H_2O$ was suggested for passivation layer and anti-reflection (AR) coating of the p-type crystalline Si (c-Si) solar cell application. It was confirmed that the deposition rate and refractive index of $Al_2O_3$ film was proportional to the $NH_4OH$ concentration. $Al_2O_3$ film deposited with 5 % $NH_4OH$ has the greatest negative fixed oxide charge density ($Q_f$), which can be explained by aluminum vacancies ($V_{Al}$) or oxygen interstitials ($O_i$) under O-rich condition. $Al_2O_3$ film deposited with $NH_4OH$ 5 % condition also shows lower interface trap density ($D_{it}$) distribution than those of other conditions. At $NH_4OH$ 5 % condition, moreover, $Al_2O_3$ film shows the highest excess carrier lifetime (${\tau}_{PCD}$) and the lowest surface recombination velocity ($S_{eff}$), which are linked with its passivation properties. The proposed $Al_2O_3$ film deposited with diluted $NH_4OH$ is very promising for passivation layer and AR coating of the p-type c-Si solar cell.

• Corrosion Science and Technology
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• v.6 no.5
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• pp.219-226
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• 2007

Pre-construction primer (PCP), or shopprimer, have been applied to steel plates to control temporary corrosion during ship fabrication. For surface preparation at ship block stage, in common shipyard practices, welding beads, burnt and rusted areas shall be blasted or power tool cleaned and the contamination such as zinc salt shall be removed with blasting or power tool. Whereas, the sound film of PCP needs not to be removed or roughened as the paint having good compatibility with PCP is used for the first coat. In many cases, however, full blasting or sweep blasting on the sound PCP treated block assemblies was requested. There still has been argument about the legitimacy of this practice, thus, it is critical to evaluate the quality of the coating system applied on the sound PCP retained condition, comparing with the one applied on the full blasted or sweep blasted condition. In this study, two different epoxy systems for water ballast tank were applied on the surfaces with sound PCP condition, full blasted condition, and sweep blasted condition. Coating performances such as durability, anti-corrosion, cathodic disbondment resistance were evaluated. The test results clearly indicated that the sound film of PCP needed not to be removed or roughened as the paint having good compatibility with PCP based on inorganic zinc silicate.

• Journal of the Korean Electrochemical Society
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• v.16 no.3
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• pp.157-161
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• 2013

Porous $LiMn_{0.6}Fe_{0.4}PO_4$ (LMFP) was synthesized by a sol-gel process. Uniform dispersion of the conductive carbon source throughout LMFP with uniform carbon coating was achieved by heating a stoichiometric mixture of raw materials at $600^{\circ}C$ for 10 h. The crystal structure of LMFP was investigated by Rietveld refinement. The surface structure and pore properties were investigated by SEM, TEM and BET. The LMFP so obtained has a high specific surface area with a uniform, porous, and web-like nano-sized carbon layer at the surface. The initial discharge capacity and energy density were 152 mAh/g and 570 Wh/kg, respectively, at 0.1 C current density, and showed stable cycle performance. The combined effect of high porosity and uniform carbon coating leads to fast lithium ion diffusion and enhanced electrochemical performance.

• Journal of the Korean Ceramic Society
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• v.35 no.11
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• pp.1155-1161
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• 1998

We have studyed the surface electric resistiance for inner conductive film consisted of graphite and iron oxide by coating the conductive paint on inner face of 28" wide CRT funnel and have evaluated the working properties of 28" wide CRT according to the surface electric resistiance. We found that the viscosity of paint and the thickness of conductive film became the higher but the surface electric resistiance of con-ductive films was the lower than before in accordance with the increase of solid contents in conductive paint and that the surface condition and the surface electric resistiance of conductive films changed highly ac-cording to the drying conditions also. From these results we could get the uniform thickness and the un-iform film resistance and the optimum working property of selectric propertise in CRT when we used the conductive paint with solid contents 28% and viscosity about 13cps.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.149-149
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• 2010

The double-layer antireflection (DLAR) coatings have significant advantages over single-layer antireflection (SLAR) coatings. This is because they will be able to cover a broad range of the solar spectrum which would enhance the overall performance of solar cells. Moreover films deposited at high frequency are expected to show excellent and UV-stable passivation in the refractive index that we adopted. In this work, we present a novel DLAR coating using SiNx:H thin films with refractive indices 1.9 and 2.3 as the top and bottom layers. This approach is cost effective when compared to earlier DLAR coatings with two different materials. SiNx:H films were deposited by Plasma enhanced chemical vapor deposition (PECVD) technique using $SiH_4$, $NH_3$ and $N_2$ gases with flow rates 20~80sccm, 200sccm and 85 sccm respectively. The RF power, plasma frequency and substrate temperature for the deposition were 300W, 13.56 MHz and $450^{\circ}C$, respectively. The optimum thickness and refractive indices values for DLAR coatings were estimated theoretically using Macleod simulation software as 82.24 nm for 1.9 and 68.58 nm for 2.3 respectively. Solar cells were fabricated with SLAR and DLAR coatings of SiNx:H films and compared the cell efficacy. SiNx:H> films deposited at a substrate temperature of $450^{\circ}C$ and that at 300 W power showed best effective minority carrier lifetime around $50.8\;{\mu}s$. Average reflectance values of SLAR coatings with refractive indices 1.9, 2.05 and 2.3 were 10.1%, 9.66% and 9.33% respectively. In contrast, optimized DLAR coating showed a reflectance value as low as 8.98% in the wavelength range 300nm - 1100nm.

• Korean Journal of Materials Research
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• v.24 no.5
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• pp.259-265
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• 2014

$ZrO_2$ films were coated on aluminum etching foil by the sol-gel method to apply $ZrO_2$ as a dielectric material in an aluminum(Al) electrolytic capacitor. $ZrO_2$ films annealed above $450^{\circ}C$ appeared to have a tetragonal structure. The withdrawal speed during dip-coating, and the annealing temperature, influenced crack-growth in the films. The $ZrO_2$ films annealed at $500^{\circ}C$ exhibited a dielectric constant of 33 at 1 kHz. Also, uniform $ZrO_2$ tunnels formed in Al etch-pits $1{\mu}m$ in diameter. However, $ZrO_2$ film of 100-200 nm thickness showed the withstanding voltage of 15 V, which was unsuitable for a high-voltage capacitor. In order to improve the withstanding voltage, $ZrO_2$-coated Al etching foils were anodized at 300 V. After being anodized, the $Al_2O_3$ film grew in the directions of both the Al-metal matrix and the $ZrO_2$ film, and the $ZrO_2$-coated Al foil showed a withstanding voltage of 300 V. However, the capacitance of the $ZrO_2$-coated Al foil exhibited only a small increase because the thickness of the $Al_2O_3$ film was 4-5 times thicker than that of $ZrO_2$ film.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 1997.11a
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• pp.130-137
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• 1997

Intumescent inorganic and organic coatings which dintr one from the other by the type of gas formers and the mechanisms of foam formation have been obtained and investigated. Inorganic intumescent coatings are the compositions based on water glass and mineral additives with different dispersity. Mineral additives contain adsorbed and absorbed water and carbonates which are destructed with the carbon dioxide and water evolution during the flame action on coating. The decreasing of mineral additives particle sizes under the mechanical milling with the fraction precipitation promotes the foam coke formation with less defects. Here the main structure of comparing compositions does not change. In organic coatings based on epoxy-polymers the polyammonium phosphate additive is used. It is the cabonization catalyst and the foam agent. The polyammonium phosphate of various dispersity employed is uniformly distributed on the polymeric matrix. The decreasing of the particle sizes leads to the increasing of the fire resistant properties of the intumescent coa-ting. The fire resistant analysis of the coating during more than an hour: the coating back side the temperature on plastic or wooden materials does not exceed 423K, and on metal-573K.