• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.137-138
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• 2008

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.398-403
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• 2001

There is a potential usability of electric arc furnace(EAF) dust produced during the iron manufacturing process as a recycled resource, because valuable materials such as Zn, Pb and Fe are contained in it. In this study, metallic Zn was recycled from the fine electric arc furnace dust by a solid state reduction method using carbon at relatively low temperature. It was possible to recover metallic zinc by using of high vapour pressure of zinc with this reduction method. The feasibility of recycled zinc for cold bonded pellet(CBP) was investigated. The main composition of EAF dust were franklinite(ZnFe$_2$O$_4$), magnetite(Fe$_3$O$_4$) and zincite(ZnO), and Pb and Cl were completely removed by a heat treatment in oxidation environment. The reduction ratio increased as the solid carbon content increased, and it increased with decreasing of dust particle size and increasing of compaction pressure due to a increase of contact area.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.2
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• pp.191-198
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• 1995

In order to evaluate the distribution and behaviour of atmospheric particulate metals in high-altitude area, we collected 22 aerosol samples using a high volume air sampler at Soback Mt. Meteorological Observation Station from Jan. to Nov. 1993 and analysed for metals (Al, Fe, Mg, Na, Ca, Mn, Co, Ni, Cu, Zn, Cd, and Pb) with ICP/AES and ICP/MS. Although sampling site is located in high-altitude and far from local sources of atmospheric pollutants, enrichments of metals are 2 times higher than those of western coastal reural area. This fact may imply that of metallic pollutants in the coastal rural site were came from further western side (e.g. China), atmospheric metals in this study area contain the signal of metropolitan cities located in the main wind direction (NNW). Sea salts are negligible in the aerosol particle population because reference elements of sea salts (Na, Mg) are all originated from soil particles. The contents of soil particles in aerosols are highest in spring and lowest in winter. Atmospheric enriched elements (Ni, Cu, Zn, Cd and Pb) are diluted with soil particles, especially during the yellow sand period. The results of factor analysis suggest possibility of interpreting their chemical significance in terms of sources (soil, pollutants) and gas-particle conversion processes (formation of ammonium sulfates, ammonium nitrates and/or their mixtures).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.7
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• pp.593-602
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• 2016

Numerical simulations on the close-coupled supersonic gas atomizer for metallic powder production were performed in this study. A proper turbulence model was chosen and then VOF(Volume of Fluid) and DPM(Discrete Phase Model) methods were sequentially applied for the simulations of primary and secondary break-up processes of liquid metal. Diameters of parent droplets were calculated by analyzing Level-Set function contour from the VOF result. Finally, the distribution of particle diameter was obtained from the DPM result at exit of the computational domain.

• Journal of Powder Materials
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• v.23 no.6
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• pp.409-413
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• 2016

Electrical wire explosion in liquid media is a promising method for producing metallic nanopowders. It is possible to obtain high-purity metallic nanoparticles and uniform-sized nanopowder with excellent dispersion stability using this electrical wire explosion method. In this study, Ni-Fe alloy nanopowders with core-shell structures are fabricated via the electrical explosion of Ni-Fe alloy wires 0.1 mm in diameter and 20 mm in length in de-ionized water. The size and shape of the powders are investigated by field-emission scanning electron microscopy, transmission electron microscopy, and laser particle size analysis. Phase analysis and grain size determination are conducted by X-ray diffraction. The result indicate that a core-shell structured Ni-Fe nanopowder is synthesized with an average particle size of approximately 28 nm, and nanosized Ni core particles are encapsulated by an Fe nanolayer.

• Elastomers and Composites
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• v.49 no.2
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• pp.160-166
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• 2014

The formulation of six basecoats was designed using aluminium pastes for the per-painted system in the automotive. The aluminium pastes contain pancake type metallic pigment, #501, #801, #601 and cornflake type metallic pigment, #750, #770, #790. The relative cure density of the basecoat increased in order of #501, #801, #601, #750, #770, #790. T-bending, impact resistance, and taping adhesion showed increment with increasing cure density. In the appearance( combined factor) test on cornflake type pigment, The basecoat including the smallest particle size pigment, #790 resulted in the best combined factor compared to other two systems(#750, #770).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.12
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• pp.1802-1812
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• 2001

The purpose of this study is to analyze numerically the movement of particles included in turbulent fluid flow characteristics of metallic surfaces. To describe fluid flew, the incompressible Navier-Stokes equation discretized by the finite volume method were solved on the non-orthogonal coordinates with non-staggered variable arrangement, and the k-$\xi$ turbulence model was adapted. After fluid flow was calculated, particle movement was predicted from the Lagrangian approaches. Non-essential complexities were avoided by assuming that the particles had spherical shapes and the Stoke's drag formula only consisted of external farces acting upon them. In order to validate the numerical calculations, the results were compared with the experimental data reported in literature and agreed well with them. The drag force coefficient equation showed better agreement with the experimental data in the prediction of particle movement than the correction factor equation. Impact velocity and impact angle increased as inlet turbulence intensity decreased, relative jet height was lower. or the Reynolds number was larger.

• Transactions of the Korean hydrogen and new energy society
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• v.16 no.1
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• pp.58-65
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• 2005

The $LaCrO_3$-dispersed Cr alloys for metallic interconnect of solid oxide fuel cell were prepared as a function of $LaCrO_3$ content in the range of 5 to 25 vol.% and were sintered at 1500$^{\circ}C$ under an Ar atmosphere with 5 vol.% $H_2$. The sintering and oxidation behaviors of these alloys were examined. The alloys indicated a good sinterability above 95% relative density at a given sintering condition, and their sintering densities is independent on $LaCrO_3$ content. The $LaCrO_3$ particles of the sintered alloys were concentrated on interfaces of Cr particles, and the size of the Cr particles increased with decreasing $LaCrO_3$ content, which is caused by inhibited grain growth of Cr particle by $LaCrO_3$ particle. The oxidation test showed all $LaCrO_3$-dispersed Cr alloys have good oxidation resistance as compared with pure Cr, which is attributed to presence of $LaCrO_3$ at the interface at which the oxidation reaction occurs rapidly. The Cr alloys with about 15 vol.% $LaCrO_3$ are very resistant to oxidation.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1303-1305
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• 1998

In order to reduce or avoid oxidation problem at operation the interconnects in SOFCs have so far mostly been made of ceramic material. It has high chemical stability both under cathode and anode condition, relatively thermal expansion coefficient that matchs that of electrolyte material YSZ. But this material shown rather weak in the low oxygen atmosphere and thermal shock, and it has lower mechanical strength than alloys. To avoid these problems one may consider to use metals or alloys as materials for interconnects. Metallic interconnects are advantageous because of their high thermal and electronic conductivities. But it has some problems, Those are high thermal expansion and oxidation at high temperature in air. To solve these problems in the interconnection material in this study, $LaCrO_3$-dispersed Cr alloys for metallic interconnector of SOFC have been investigated as a fuction of $LaCrO_3$ content in the range of 5 to 25 vol.%. The Cr alloy were prepared by mixing Cr and $LaCrO_3$ powders in high-energy ball mill for 48h and by sintering under Ar atmosphere with 5vol.% $H_2$ for 10h at $1500^{\circ}C$. The alloys had a relative density of 95% and above. The Cr alloys in composed of two kind of small $LaCrO_3$ and large Cr particles. As the $LaCrO_3$ content increased, the Cr particle size decreased but the $LaCrO_3$ particle size remained contant. Also the oxidation tests show that the $LaCrO_3$-dispersed Cr is very resistant to oxidation in air. These results means that $LaCrO_3$-dispersed Cr is a useful material for metallic interconnect of planar SOFC.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.417-418
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• 2002

The dry sliding tribological characteristics were investigated using SiC particle-reinforced aluminum composites against semi-metallic frictional materials. The experimental results have indicated that, whether under the condition of continuous braking or not, the wear rates of SiC particle reinforced composites are much less than that of gray cast iron which is used as one of the common brake disk materials. At the same time, their frictional coefficients are about the same.