• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.71-74
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• 1998

$Er^{3+}$ doped $NdF_{3}$ single crystalline thin films with smooth, microcrack-free, and high-crystalline quality were grown on $CaF_{2}(111)$ substrate at $500^{\circ}C$by molecular beem epitaxy(MBE). The relation-ship between subcell and supercell showing the reconstructed $3^{1/2} \times 3^{1/2}$ structure was studied by reflection high-energy electron diffraction(RHEED) investigation. The film surface and the growth mode were examined in studied by RHEED patterns and atomic force microscope(AFM) images ex situ. The crystallinity of film and the lattice mismatch between $NdF_{3}Er}^{3+}(0002)$ film and $CaF_{2}(111)$ substrate depending in the $Er^{3+}$ concentration were investigated by X-ray rocking curve analysis.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.3-7
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• 1998

The rare-earth ions (R3+, R=Nd, Er) doped CaF2 layers have been grown on CaF2(111) substrate by molecular beam epitaxy. The epitaxial relationship and the crystallinity of CaF2:R3+ layers depending on the concentration of R3+ were studied by reflection high-energy electron diffraction (RHEED). In aspect of application as buffer layer in semiconductor-related hybrid structure, the lattice displacement between CaF2:R3+ layers and CaF2(111) substrate was investigated by X-ray rocking curve analysis.

• Communications of the Korean Mathematical Society
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• v.19 no.1
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• pp.35-51
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• 2004

We introduce fuzzy closure systems and fuzzy closure operators as extensions of closure systems and closure operators. We study relationships between fuzzy closure systems and fuzzy closure spaces. In particular, two families F(S) and F(C) of fuzzy closure systems and fuzzy closure operators on X are complete lattice isomorphic.

• Journal of Magnetics
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• v.2 no.2
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• pp.35-37
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• 1997

A sample of YBa2Cu3O7-x fluorinated by a high temperature (400$^{\circ}C$) gas exchange technique has been investigated by means of 19F NMR (nuclear magneti resonance) measurements in both superconducting and normal state. As a result, behaviors characteristic of the superconductor, including a peculiarity in the spin-lattice relaxation rate (1/T1) around 250 K, were observed.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.145-148
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• 1998

Fluoride({{{{ { CaF}_{2 } }}}}) films exhibited a cubic structure with similar lattice constant to that of Si and have sufficient breakdown electric field as gate dielectric material. Therefore, {{{{ { CaF}_{2 } }}}} are expected to replace conventional insulator such {{{{ { SiO}_{ 2},{Ta}_{2}{O}_{ 2} and{Al}_{2}{O}_{5}. However, {CaF}_{2}}}}} films showed hystereisis properties due to mobile charges in the film. To solve this problem we performed thermal treatment and achieves field. C-v results indicate a reduced hystereisis window of {{{{ }}}}ΔV =0.2v, LOW INTERFACE STATE {{{{{D}_{it}=2.0 TIMES {10}^{11}{cm}^{-1}{eV}^{-1}}}}} in midgap, and good WIS diode properties. We observed a preferential crystallization of(200) plane from XRD analysis. RTA treatment effects on various material properties of {{{{{CaF}_{2}}}}} are presented in this paper.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.9 no.1
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• pp.1-5
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• 1999

The rare-earth ions ($R^{3+}$, R=Nd, Er) doped $CaF_{2}$ layers have been grown on $CaF_{2}$ (111) substrate by molecular beam epitaxy. The surface structure and the crystallinity of $CaF_{2}:R^{3+}$ layers depending on the doping concentration of $R^{3+}$ and layer thickness were studied by reflection high-energy electron diffraction (RHEED). In aspect of application as buffer layer in semiconductor-related hybrid structure, the lattice displacement between $CaF_{2}:R^{3+}$ layers and $CaF_{2}$ (111) substrate was investigated by X-ray rocking curve analysis.

• Korean Institute of Interior Design Journal
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• v.25 no.3
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• pp.60-69
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• 2016

This experimental study measures the emotional and physiological responses of customers as to cafe facade design. It is done through eye-tracking and EEG response experiments. Specifically, their visual concentration and EEG concentration are analyzed in line with their facade preferences. The findings are as follows. First, the correlation between their facade preferences and visual concentration on facades is as follows: Highly preferable facades have a lower visual concentration frequency than the less preferable facades. Second, an analysis of $12{\times}12$ lattice division of facades shows that all facades have a high visual concentration for signs. The exceptions are F(6), F(7), F(8), and F(10). There is no correlation between the facade preferences and visual concentration behaviors for particular facade elements. Third, an analysis of prefrontal lobe's facade concentration shows that there is no correlation between the preferences and EEG concentration. However, there are big differences in the prefrontal lobe activity of 12 subjects depending on the facade. In particular, nine of them (3, 9, 13, 14, 15, 28, 36, 38, 43) show an activated prefrontal lobe as to the highly preferable facades-F(1), F(2), F(3), and F(4). However, such activation is not detected on the less preferable facades-F(9), F(10), F(11), and F(12).

• Proceedings of the Korean Vacuum Society Conference
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• 2005.02a
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• pp.38-38
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• 2005

• Journal of applied mathematics & informatics
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• v.6 no.1
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• pp.247-252
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• 1999

The purposed of this paper is to introduced some basic concepts of Galois connection between fuzzy ordered sets. And discuss its relations with the property of fuzzy ordered set.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.24 no.4
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• pp.140-144
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• 2014

Co-(0.7 wt%) and Pr-(2.0, 3.5 or 5.0 wt%) doped cubic zirconia ($ZrO_2:Y_2O_3=50:50wt%$) single crystals grown by a skull melting method were heat-treated in $N_2$ at $1150^{\circ}C$ for 5 hrs. The brown colored as-grown single crystals were changed into either dark brownish green, greenish blue and light green color after the heat treatment. Before and after the heat treatment, the YSZ (yttria-stabilized zirconia) single crystals were cut for wafer form (${\phi}7.5mm{\times}t3mm$). The optical and structural properties were examined by UV-VIS spectrophotometer and X-ray diffraction. Absorption by $Co^{2+}$(${\fallingdotseq}589nm$: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_8+{\Gamma}_7[^4T_1(^4F)]$, ${\fallingdotseq}610nm$: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_8[^4T_1(^4F)]$], ${\fallingdotseq}661nm$: ${\Gamma}_8[^4A_2(^4F)]{\rightarrow}{\Gamma}_6[^4T_1(^4F)]$]) and $Pr^{3+}$(${\fallingdotseq}450nm$: ${^3}H{_4}-{^3}P{_2}$, ${\fallingdotseq}473nm$: ${^3}H{_4}{\rightarrow}{^3}P{_1}$, ${\fallingdotseq}484nm$: ${^3}H{_4}{\rightarrow}{^3}P{_0}$), change of ionization energy and lattice parameter were confirmed.