Papers by Author: Tae Yeoung Lim

Abstract: Electrochromic WO3 thin film was prepared by using tungsten metal solution in hydrogen peroxide as a starting solution and by a sol-gel dip coating method. The thermal analysis was conducted by DSC/TG method. A DSC/TG analysis and the XRD patterns showed that a tungsten oxide crystal phase was formed at 400oC. WO3 thin film when heat-treated at 300oC was amorphous and had a better electrochemical property than that of the crystalline phase. Crystallization of tungsten oxide decreased active sites of ion intercalation so that the current density decreased with heat-treatment temperature.

Abstract: Color sol was fabricated and coated it on glass substrate using sol-gel method. Silicate sol prepared by the use of commercially available tetraethoxysilane(TEOS), tetramethoxysilane (TMOS), methoxysilane(MTSO), phenytrimethoxysilane(PTMS) as a raw material of alkoxysilane family, and C.I. solvent red 122 and C.I. solvent yellow 82 as a organic dye, and C.I. pigment blue 28 and C.I. pigment red 26 as a pigment. Colored thin films were fabricated with changing the withdrawal speed by dip coating method, and heat treatment at 100~400°C. The visible light transmittance of colored thin film was measured with UV/VIS spectrophotometer, the surface hardness measured by pencil test, the surface turbidity measured by haze meter, and the film thickness was measureded by Alpha-step surface profiler.

Abstract: Electrochromic WO3 thin film was prepared by using tungsten metal solution in hydrogen peroxide as a starting solution and by sol-gel dip coating method. XRD pattern showed that tungsten oxide crystal phase formed at 400
. In the view of electrochemical property, WO3 thin film which was heat-treated at 300
and was amorphous had better than that of the crystalline phase.

Abstract: The porous ceramic panel using glass powder as a main raw material can be applied for the thermal insulator in architecture and industry since it is noncombustible and chemically stable as well as eco-friendly unlike the organic thermal insulators. For the study of fabrication and characterization of this material, we used grinded glass powder with grain size smaller than 150
, and Calcium carbonate(CaCO3) and Calcium phosphate(Ca3(PO4)2, CaHPO4·2H2O) as foaming agent. The shape and size of pore cell in porous glass structure with the change of additives and sintering temperature were studied. The physical properties as like density, thermal conductivity and compressive strength of materials are also studied. It was possible to make a porous ceramic panel with multi-layered which has the form of sandwich with layer of low density and high density in one body by adjusting the foaming characteristics.

Abstract: The effect of RO components variation on some properties was studied in Pb free glass frit for PDP (Plasma Display Panel). One of the main components, BaO, was replaced progressively at fixed concentration of alkaline earth oxides. We studied the transparency, thermal expansion, softening point, and the high temperature microscopic behaviors of glass frits and TG(thermal gravimetry) of raw material. The compositional dependence of those properties was discussed from the view points of compositional diversity and production process of Pb free glass frit.