• Journal of the Korean Ceramic Society
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• v.31 no.7
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• pp.804-812
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• 1994

Stable PZT coating sol was prepared using chelating agent, ethylacetoacetate(EAcAc) by sol-gel processing under ambient atmosphere. Through FT-IR spectrum analysis on solution of each reaction step, formation of metal complex was confirmed and prepared PZT sol was stable over several months. Through TG-DTA, XRD, FT-IR spetrum analysis of PZT gel powder, it was understood that the addition of EAcAc could reduce the transition temperature to ferroelectric phase, due to the increased homogeneity by matching the hydrolysis and condensation rates by chelation. Single perovskite phase was obtained by the heat-treatment at 54$0^{\circ}C$ for 30 min. The film was coated on ITO-coated glass substrate by dip coating method. After heat-treatment, PZT thin film had thickness in the range of 20~130 nm. The maximum dielectric constant of its thin film at room temperature and 1 kHz was 128.

• Journal of the Korean Ceramic Society
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• v.34 no.8
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• pp.825-833
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• 1997

Silicon carbide films were deposited by low pressure chemical vapor deposition(LPCVD) using MTS(CH3SICl3) in hydrogen atmosphere on (100) Si substrate. To prevent the unstable interface from being formed on the substrate, the experiments were performed through three deposition processes which were the deposition on 1) as received Si, 2) low temperature grown SiC, and 3) carbonized Si by C2H2. The microstructure of the interface between Si substrates and SiC films was observed by SEM and the adhesion between Si substrates and SiC films was measured through scratch test. The SiC films deposited on the low temperature grown SiC thin films, showed the stable interfacial structures. The interface of the SiC films deposited on carbonized Si, however, was more stable and showed better adhesion than the others. In the case of the low temperature growth process, the optimum condition was 120$0^{\circ}C$ on carbonized Si by 3% C2H2, at 105$0^{\circ}C$, 5 torr, 10 min, showed the most stable interface. As a result of XRD analysis, it was observed that the preferred orientation of (200) plane was increased with Si carbonization. On the basis of the experimental results, the models of defect formation in the process of each deposition were compared.

• Korean Institute of Interior Design Journal
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• v.14 no.3 s.50
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• pp.114-121
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• 2005

Louis 1. Kahn was a wise architect who learned from history. He developed his own unique architecture by combining his creative sense with design principles and vocabularies that can be found in historical architecture. When restricting a space, he surrounded the space with thick walls as it had been done in historical buildings. The interior space encompassed by this method became a center-oriented and stable space. The objective of this study is to find the characteristics of Kahn's interior spaces by analyzing his projects in terms of space, form, daylight and materials. For this purpose, five works that are considered to have significance from the aspect of interior design were selected and analyzed. The characteristics realized through this study are as follows. A) Spatial features: 1) Generally speaking, each required space has been arranged symmetrically. 2) Being clearly defined as the main space, the subsidiary space, or the service space, each space also was placed very functionally. 3) The space encompassed by thick walls became a center-oriented, stable space. And in most case, it was characterized as a dark space. B) Formative features: 4) The space was defined as a basic solid such as a cylinder, a hexahedron, and an octagonal box, and was developed into a complex shape by the recessed windows. 5) Historical vocabularies such as an arch, a vault, and a dome were reinterpreted in new ways by kahn's own eyes. 6) Haying diverse shapes, the skylights enrich the space in terms of form. C) Daylight feature: 7) The vertical light entering through the skylights creates a solemn and mysterious atmosphere. 8) Given the shadows from the windows that change according to time, the interior space becomes a very vivid space. D) Material feature: 9) Harmonized with cold and smooth materials such as exposed concrete, metal, and glass, the interior space provides a modern atmosphere. 10) Warm appearing wood was used for furniture and part of walls or floors. The effective use of wood takes on a role that is quite complementary to the cold ambience of the smooth and cold materials. 11) With flexibility In building shapes, the concrete becomes the form-endowing materials.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1989-1991
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• 1999

This paper presents characteristics of CrN thin-film strain gauges, which were deposited on glass by DC reactive magnetron sputtering in an argon-nitrogen atmosphere(Ar-$(5{\sim}25%)N_2$). The physical and electrical characteristics of these films investigated with the thickness range $3500{\AA}$ of CrN thin films, annealing temperature $(100{\sim}300^{\circ}C)$ and annealing $(24{\sim}72hr)$. The optimized condition of CrN thin-film strain gauges were thickness range of $3500{\AA}$ and annealing condition($300^{\circ}C$, 48 hr) in Ar-10 %$N_2$ deposition atmosphere. Under optimum conditions, the CrN thin-films for strain gauge is obtained a high resistivity, ${\rho}=1147.65{\mu}{\Omega}cm$, a low temperature coefficient of resistance, TCR=$-186ppm/^{\circ}C$ and a high temporal stability with a good longitudinal, 11.17. And change in resistance after annealing for the CrN thin-films were quitely linear and stable.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.528-535
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• 1997

$LiTaO_3$ single crystals of congruently melting composition were grown by the halogen lamp type floating zone system. Calcination and sintering parameters for the growth were established. Optimum crystal growth conditions were investigated by a controlling of growth rates, rotation speeds and atmospheres. Based on the melting aspect and the shape of molten zone, stable conditions could not be found in air or Na atmosphere. However the growth stability in Ar atmosphere was more regular than that in air or $N_2$. The grown crystals were characterized using Laue back reflection, Curie temperature, refractive index and transmittance. Curie temperature fluctuation in the section of the grown crystal part of top, body and tail was $1^{\circ}C$.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2006.05a
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• pp.99-100
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• 2006

The concept of dental clinic have been changed along the advanced dental science to meet the need of setting up high-technology-digital appliances. As the general idea about the dental clinic has been changed from systematic connection, the expansion of zoning needs to become more accurate and mote detailed. In the spacious waiting room. the interment cafe has been established to supply the information services, and the various multi-imaged channels, which were built in, will relieve the boredom of the waiting time. The formation of water space leads to the effect of humidification and makes parents share visual and auditory sympathy All of the unit-chairs attached cameras in the consultation room enables people to diagnose more quickly and precisely through the computerized system. Partitions have been set of to put it in and to help diagnosis process to be done smoothly in the formational space. The whole atmosphere is intended to be harmony with the natural surroundings in Je-Ju. It will inspire people visiting this clinic to image the deep blue sea in Je-Ju. By using projective non-material a lot, especially material wooden windows and doors, it is believed to create the bright and stable atmosphere. It will lead patients feel comfortable.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.823-827
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• 2001

The AgInS$_2$epilayers with chalcopyrite structure grown by using a hot-wall epitaxy (HWE) method have been confirmed to be a high quality crystal. From the optical absorption measurement, the temperature dependence of the energy band gap on the AgInS$_2$/GaAs was derived as the Varshni's relation of Eg(T)=2.1365 eV-(9.89${\times}$10$\^$-3/ eV)T$^2$/(2930+T). After the as-grown AgInS$_2$/GaAs was annealed in Ag-,S-, and In-atmosphere, the origin of point defects of the AgInS$_2$/GaAs has been investigated by using the photoluminescence (PL) at 10 K. The native defects of V$\_$Ag/, V$\_$s/, Ag$\_$int/, and S$\_$int/ obtained from PL measurement were classified to donors or acceptors type. And, we concluded that the heat-treatment in the S-atmosphere converted the AgInS$_2$/GaAs to optical p-type. Also, we confirmed that the In in the AgInS$_2$/GaAs did net from the native defects because the In in AgInS$_2$did exist as the form of stable bonds.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.04a
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• pp.318-322
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• 1997

The (Sr$_{l-x}$.Ca$_{x}$)TiO$_3$(0.05$\leq$x$\leq$0.2) ceramics were fabricated to form semiconducting ceramics by sintering at about 1350[$^{\circ}C$] in a reducing atmosphere($N_2$gas). After being fired in a reducing atmosphere, metal oxides, CuO, was painted on the both surface of the specimens to diffuse to the grain boundary. They were annealed at 1100[$^{\circ}C$] for 2 hours and cooled to room temperature. The grain boundary was composed of the continuous insulating layers. The capacitance changes slowly and almost linearly in the temperature region of -30~+85[$^{\circ}C$]. The capacitance characteristics appears a stable value within $\pm$10[%]. The conduction mechanism of the specimens observed in the temperature range of 25~125[$^{\circ}C$], and is divined into three regions haying different mechanism as the current increased: the region I below 230[V/cm] shows the ohmic conduction. The region II can be explained by the Poole-Frenkel emission theory, and the region III is dominated by the tunneling effect.ect.

• The Korean Journal of Ceramics
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• v.1 no.2
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• pp.86-90
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• 1995

Theoretical predictions for thermodynamically stable phases which formed when alkali(sodium and potassium) vapors reacted with alumina-chromia refractories under coal gasifying atmosphere were confirmed experimentally using a laboratory-scale coal gasifying reaction system and a commercial alumina-chromia refractory using SEM, XRD, and EDAX. Alkali concentration profiles in the refractory as a function of time were also determined. The results showed that the compounds that formed were $X_2O{\cdot}Al_2O_3, X_2O{\cdot}Cr_2O_3, X_2O{\cdot}5Al_2O_3, X_2O{\cdot}7Al_2O_3, X_2O{\cdot}11Al_2O_3(X=Na^+ \;or\; K^+)$, depending upon the alkali concentration and time of exposure at high temperatures. The presence of sulfur in gasifying atmospheres did not appear to affect the alkali reaction produces. Alkali pentration into the alumina-chromia refractory was deep and the formation of the $Na_2O{\cdot}Al_2O_3/K_2O{\cdot}Al_2O_3$ compunds resulted in the serious deformation of the refractory due to the large volume expansion at the reaction surface. The hot face of the alumina-chromia refractory in service under an alkali environment is prone to failure by alkali attack.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.12
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• pp.1016-1022
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• 2001

This study presents the microstructure-electrical property relationship of reactive-sputtered Ta$_2$O$_{5}$ MIM capacitor structure processed by annealing in a vacuum and $O_2$ ambience. A microstructural investigation showed the existence of amorphous phase in as-deposited condition and the formation of preferentially oriented-Ta$_2$O$_{5}$ in $700^{\circ}C$ annealing. On annealing under the $O_2$ atmosphere, the Ta$_2$O$_{5}$ film exhibited the trend of its composition\`s approaching to stoichiometry from off-stoichiometry, analyzed by EPMA, the leakage current decrease and the enhanced temperature-capacitance characteristic stability. In the case of low temperature vacuum-annealing treatment, the leakage current behavior was stable irrespective of applied electric field. In the high temperature-annealed film at a vacuum condition, the electrical properties was observed to deteriorate. The results state that in Ta$_2$O$_{5}$ film annealed at $O_2$ atmosphere, gives rise to improvement of electrical characteristics in the capacitor were improved by reducing oxygen-vacancy and dandling Ta-O bond.-O bond.