• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.89-92
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• 2004

This paper is concerned with the drawing process of Al-Si wire. In this study, the finite-element model established in previous work was used to analyze the effects of various forming parameters, which included the reduction in area, the semi-die angle, the aspect ratio and the inter-particle spacing of the Si in drawing processes. The finite-element results gave the consolidation condition. From the results of analysis, the effects of each forming parameter were determined. It is possible to obtain the important basic data which can be guaranteed in the fracture prevention of Al-Si wire by using FEM simulation.

• Journal of the Mineralogical Society of Korea
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• v.21 no.1
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• pp.27-35
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• 2008

Characterization of mineralogy and nanocrystals of ingredient materials of $Lumilite^{(R)}$ used for water treatment was made using optical microscopy, XRD, SEM, FTIR, and XRF analyses. Constituent minerals identified by XRD and microscope are clinoptilolite, illite, quartz, and albite, characterized by dense and fine texture. The cross section of nanocrystals with the size $70{$\sim}100\;nm$ is generally round or subround. Numerous spheroids with few nanometers in diameter are extensively formed on the surface of nanocrystals. Bulk chemistry is $SiO_2$ $74.22{\sim}75.65\;wt.%$, $Al_2O_3$ $13.25{\sim}13.72\;wt.%$, CaO $4.23{\sim}5.15\;wt.%$, with other major elements being minimal. When heated to $700^{\circ}C$, the crystal structure was mostly destroyed, though it persisted to $500^{\circ}C$. It is likely that high capacity and applications of $Lumilite^{(R)}$ for water treatment are originated from its structural properties such as development of nanocrystals and various tiny pores.

• Journal of the Korean Ceramic Society
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• v.35 no.1
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• pp.97-105
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• 1998

20mol% Gd-doped CeO2 ultrafine powders as a promising electrolyte for the low temperature solid ox-ide fuel cells were synthesized with particle sizes of 15-20 nm using glycine nitrate process(GNP) fol-lowed by sintering their pellets at 150$0^{\circ}C$ for various times in air and then the electrical properties of the sintered pellets were investigated. The sintering behaviors and electrical properties for the sintered 20 sintered mol% Gd-doped CeO2 pellets were analyzed using dilatometer and SEM and AC two-terminal impedance technique respectively. As the heating temperature increased the synthesized powder had the sintering behaviors to show the start of the significant shrink at temperature of about $700^{\circ}C$ and to show the end of the shrink at the temperature of about 147$0^{\circ}C$. When the pellets were sintered with the vaious times at 150$0^{\circ}C$ the temperatuer which the shrink had been already completed the grain sizes in the sintered 20 mol% Gd-doped GeO2 pellets increased with the increase of the sintering time but their electrical resis-tivities showed the minimum value at the sintering time of 10h. It is due that the pellet sintered for 10h had the minimum activation energy fior the electtrical conduction. Thus it is thought that the decrease of the activation energy with the increase of the sintering time to 10h is induced by the enhanced mi-crostructure like the decrease of pore amount and the grain growth and its increase with the sintering times more than 10h is induced by the increase of the amounts of the impurities such as Mg. Al and Si from the sintering atmosphere.