• Journal of Powder Materials
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• v.4 no.4
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• pp.291-297
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• 1997

Titanium cabide, TiC-x mole% Al composites, and functionally-graded materials (FGMs) of TiC-x mole% Al were synthesized by an electrothermal combustion (ETC) method. TiC-70 mole% Al composite was not ignited by indirect tungsten coil heating, but can be synthesized by an electrothermal combustion. The velocity of the combustion wave decreased with increasing addition of Al and increased with an increase in the applied electric field. Functionally-graded TiC-Al materials were made from reactant layers with compositions of Ti+C+x moles Al with x ranging from zero to 70 by an electrothermal combustion. In the FGM products a nearly linear change in composition in the graded region was observed in samples with 0$\leq$ x $\leq$ 70 with x being the mole% Al.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1464-1466
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• 2007

We demonstrate p-doped organic light emitting diodes (OLEDs) comprising tungsten oxide ($WO_3$) and 1,4-bis[N-(1-naphthyl)-N'-phenylamino]-4,4' diamine (NPB). We propose the NPB : $WO_3$ composition functions as a p-doping layer which significantly improves hole injection that leads to the fabrication of 4-(dicyano-methylene)-2-methyl-6-(p-dimethylaminos tyryl)-4H-pyrane (DCMl) based p-doped OLEDs with high efficiency and long lifetime.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.1
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• pp.34-42
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• 2001

The influences of substrate temperature were studied when fabricating KLN thin film on amorphous substrate using an rf-magnetron sputtering method. Investigating the vaporization temperature of the each element, the excess ratio of target and the optimum deposition conditions were effectively selected when thin filmizing a material which have elements with large difference fo vaporization temperature. In order to compensate K and Li which have lower vaporization temperatures than Nb, KLN target of composition excess with K of 60% and Li of 30% was used. KLN thin film fabricated on Corning 1737 glass substrate had single KLN phase above 58$0^{\circ}C$ of substrate temperature and crystallized to c-axis direction. The optimum conditions were rf power of 100W, process pressure of 150mTorr, and substrate temperature of $600^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.603-604
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• 2006

We investigated the effects of oxidizer additive on the performance of Cu-CMP process using commonly used tungsten slurry. According to the CMP removal rates and particle size distribution, and the micro- structures of surface layer as a function of oxidizer contents were greatly influenced by the slurry chemical composition of oxidizers. The difference in removal rate and roughness of copper surface are believed to cause by modification in the mechanical behavior of $Al_{2}O_3$ abrasive particles in CMP slurry.

• Economic and Environmental Geology
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• v.16 no.1
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• pp.37-49
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• 1983

The skarn type tungsten deposits are developed in the contact aureole of Jurassic biotite-hornblende granodiorite and limestone beds. The latter can be divided into the Great Limestone Series of Joseon System and Gabsan Formation which is correlative to the Hongjeom Series of Pyeongahn System. The skarns are impregnated in the limestone, sandstone, schist and granodiorite, and showing zonal distribution. The five skarn zones are from fresh limestone inwards to wollastonite-skarn, clinopyroxene-skarn, clinopyroxene-garnet skarn, garnet skarn and vesuvianite skarn zone. The ore mineral, scheelite, disseminates in the clinopyroxene-garnet and vesuvianite skarn zone, and the size of the scheelite crystals in vesuvianite skarn zone is larger than in clinopyroxene- garnet skarn zone. According to the mineral paragenesis and the composition of skarn minerals, oxygen fugacity ($fo_2$) is low. Fluid inclusions in quartz comprise much $LCO_2$ and fluid inclusion studies revealed that the homogenization temperatures range $240-290^{\circ}C$.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.100-105
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• 1999

This work analyses the effects of electrical conductivities of dielectric and cobalt amount on output parameters such as metal removal rate and the surface roughness value of cemented carbides cut by wire electrical discharge machining(W-EDM). Especially, the cracking behaviour of W-EDM machined surface and optimal machining condition of three kinds of cemented carbides, which have different chemical composition of tungsten carbide and cobalt are also tested. Experimental result shows that increases in cobalt content and electrical conductivity of the dielectric affect the metal removal rate and substantially worsen the final surface quality as a greater quantity of solidified metal deposits on the eroded surface.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.191-194
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• 2009

PtRu based and PtSn based ternary catalysts were prepared by a conventional impregnation method using NaBH4 as reducing agent. The alloy formation, crystalline size and chemical composition of the in-house catalysts were determined by XRD, TEM and EDX, respectively. The chemical compositions of in-house catalysts were quite similar to the nominal value and good alloy formations were also observed. Further, crystalline sizes of ternary catalysts were comparatively smaller than binary catalysts and were approximately 3.5 ~ 5.5 nm. The electrochemical measurements were carried out in the solution 1 M $H_2SO_4$ with 1 M $C_2H_5OH$ at room temperature. LSV results obtained that ternary catalysts were higher current densities and specific activities. Especially, in case of tungsten addition system, Pt5Sn4W/C have the highest specific activities values and was approximately 21.2 and 3.1 times higher than that of PtRu/C and PtSn/C electrocatalyst.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1269-1270
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• 2006

We investigated the effects of oxidizer additive on the performance of Cu-CMP process using commonly used tungsten slurry. According to the CMP removal rates and particle size distribution, and the micro-structures of surface layer as a function of oxidizer contents were greatly influenced by the slurry chemical composition of oxidizers. The difference in removal rate and roughness of copper surface are believed to cause by modification in the mechanical behavior of $Al_2O_3$ abrasive particles in CMP slurry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.05a
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• pp.133-135
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• 2006

SBN60 and SBN60/30 thin films were deposited by ion beam sputtering technique. Using the ceramic target of the same composition and Pt(100)/$TiO_2$/$SiO_2$/Si or Pt(111)/Ti/$SiO_2$/Si substrate, crystallization and orientation behavior as well as electric properties of the films were examined, Thickness was controlled to $3000{\AA}$ and the films were heat-treated at $650^{\circ}C{\sim}800^{\circ}C$. The orientation and crystallization behavior were observed which showed the dependence on processing condition($O_2$/Ar ratio, substrate temp, annealing temp...).

• Journal of the Korean institute of surface engineering
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• v.35 no.2
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• pp.122-128
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• 2002

This study was conducted to synthesize the diamond like carbon films by plasma enhanced chemical vapor deposition (PECVD). The effects of gas composition on growth and mechanical properties of the films were investigated. A little amount of hydrogen or oxygen were added to base gas mixture of methane and argon. Methane dissociation and diamond like carbon nucleation were enhanced by installing negatively bias grid near substrate. The deposited films were indentified as hard diamond like carbon films by micro-Raman spectroscopy. The surface and fractured cross section of the films which were observed by scanning electron microscopy showed that film growth is very slow as about 0.3$\mu\textrm{m}$/hour, and relatively uniform with hydrogen addition. Vickers hardness of tungsten carbide (WC) cutting tool increased from about 1000 to 1600~1800 by deposition of DLC film, that of commercial TiN coated tool was about 1270. In cutting test of aluminum 6061 alloy, DLC coated cutting tool showed 1/3 or lower crater and flank wear than TiN coated or non-coated WC cutting tools.