• Nano
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• v.13 no.10
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• pp.1850119.1-1850119.6
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• 2018

$Eu^{3+}/Tb^{3+}$ co-doped nanocomposite containing $CeO_2$ nanocrystals was successfully prepared by an in situ sol-gel polymerization approach. High-resolution transmission electron microscopy demonstrated the homogeneous precipitation of $CeO_2$ nanocrystals among the polymethylmethacrylate (PMMA) matrix. The thermal stability and UV-shielding capability of the obtained nanocomposite were improved with increase of $CeO_2$ content. The tuning of the emissive color from green and yellow to red can be easily achieved by varying the dopant species and concentration. These results suggested that the obtained nanocomposite could be potentially applicable in transparent solid-state luminescent devices.

• The KIPS Transactions:PartB
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• v.15B no.2
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• pp.113-122
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• 2008

While there are about 1 million color vision deficiencies in Korea, an assistive technology to digital contents of broadcasting and web for them remains scarce. In this study, we developed a generation method of the ICC profile to correct a graphic digital content adapted to various color perception characteristics of CVD by tuning the correction rules of the ICC profile by themselves. We tested the performance of the ICC profile to apply 10 Ishihara plates to the participants, 1 protanomaly, 1 protanomaly and deuteranomaly and 2 deuteranomaly. We used the color range information to build correction rules. Results of the test show that they passed Ishihara test by 97.5% success rate, compared to 20% success rate without it. The average time for them to spend to tune the customized ICC profile was about 13 minute without any diagnosis of specialist, any special instrument.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.197-197
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• 2016

Quantum dot nanocrystals(QDs) have been emerged as next generation materials in the field of energy harvesting, sensor, and light emitting because of their compatibility with solution process and controllable energy band gap. Especially, characteristics of color tuning and color purity make it possible for QDs to be used photoluminescence materials. Photoluminescence devices with QDs have been researched for a long time. Photoluminescence quantum yield(PL QY) is important factor that defines the performance of Photoluminescence devices. One of the ways to achieve better PL QY is ligand modification. If ligands are changed to proper electron donating group, electrons can be confined in the core which results in enhancement of PL QY. Because of the reason, short ligands are preferred for enhancing PL QY. Thiophenol-based ligands are shorter than typical alkyl chain ligands. In this study, the effect of thiophenol-based ligands with different functional groups are investigated. Four different types of thiophenol-based organic materials are used as organic capping ligand. QDs with bare thiophenol and fluorothiophenol show better quantum yield compared to oleic acid.

• Journal of the Korean Ceramic Society
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• v.53 no.1
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• pp.50-55
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• 2016

In order to make a highly ordered three-dimensionally macro-porous structure of zirconia ceramics, porogen precursors PMMA beads were prepared by emulsion polymerization using acrylic monomer. The monodisperse PMMA latex beads were closely packed by centrifugation as a porogen template for the infiltration of zirconium acetate solution. The mixed compound of PMMA and zirconium acetate was dried. According to the firing schedule, dry compacts of PMMA and zirconium acetate were calcined at $475^{\circ}C$ to obtain micro-, macro-, and meso- structures of polycrystalline zirconia with monodispersed porosity. Inorganic frameworks composed of $ZrO_2$ were formed and showed a three Dimensionally Ordered Microstructure [3DOM] of $ZrO_2$ ceramics. The obtained $ZrO_2$ skeleton was calcined at $710^{\circ}C$. The 3DOM $ZrO_2$ skeleton showed color tuning in solutions such as deionized [DI] $H_2O$ and/or methanol. The monodispersed crystalline micro-structure with micro/meso porosity was observed by FE-SEM.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.507-509
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• 2005

This paper introduce about development of effective alarm system to apply to power system. This system includes index-components that display alarm information. It was changed color or position, value, etc by operator's tuning. According to use this system, User can not only perform easily a series of alarm analysis, but also can deal with custom system for only user.

• Journal of Integrative Natural Science
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• v.2 no.3
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• pp.219-223
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• 2009

Easy and simple synthesis of CdSe nanocrystals was achieved through sol-gel process. CdSe nanocrystals were synthesized from the reaction of cadmium oxide and selenium in the prescence of trioctylphosphine oxide, tributylphosphine, octadecene, octadecylamine, and stearic acid. The effect of reaction temperature for the determination of size of CdSe nanocrystals was investigated after the addition of selenium. The reaction temperature for the growth of CdSe nanocrystals was increased by every $20^{\circ}C$ from 170 to 190, 210, 230, 250, 270, and $290^{\circ}C$. When the reaction temperature was higher, the absorption wavelength in the absorption spectrum was increased which indicated that the size of CdSe nanocrystals was increased. The emission wavelength in the photoluminescence spectrum was increased from 438 to 489, 542, 591, 643, 692, and 745 nm, as the size of CdSe nanocrystals was increased. The control of the reaction temperature illustrated that the color tuning of emission wavelength were successfully obtained.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2005.05a
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• pp.263-266
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• 2005

This work aims at the design of the artwork for the atrium of a furniture department store. In complying with the request of the building owner I have established the basic concept, 'silence in movement - movement in silence', to design a artwork, which not only can make the various atmospheres in the store to the unique one, but also arrange an emotional stability for the visitors. Most exhibited furnitures are those that demand particular interests from the visitors, and the exhibition scale is enormous. So it is difficult to sustain the continuous inspiration and the emotional stability, and also it is hard to make the store have the consequent image. This problem can be resolved through the installation of the artwork that can evoke the visitor to the abundant sensitive receivability. The materials, which are used tp express the basic concept, are water, concrete, light and aluminium that represent a unified harmony in a contrast each other.

• Bulletin of the Korean Chemical Society
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• v.22 no.7
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• pp.727-731
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• 2001

Conjugated-non-conjugated alternating block copolymers containing distyrylarylene units were synthesized via Wittig reaction for chemiluminescent fluorophores. The polymers were differentiated from others by the presence of aromatic unit in the chromophoric block. When UV-VIS, photoluminescence and chemiluminescence spectra of these materials were compared with copolymers, a strong bathochromic effect was observed. A more pronounced red shift and higher chemiluminscence efficiency were observed in the polymer with anthracene ring. Sodium salicylate-catalyzed reaction of bis(2-carbopentyloxy-3,5,6-trichlorophenyl) oxalate with hydrogen peroxide produced a strong chemiluminescence from blue to yellow-green light emission with wavelength of 450-537 nm in the presence of the fluorophore. The chemiluminescent intensity decayed exponentially. The glow of chemiluminescence maintained more than l2 hr and was visible with the naked eye.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2309-2314
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• 2010

Design and syntheses of four red phosphorescent heteroleptic cationic iridium(III) complexes containing two substituted phenylquinoxaline (pqx) or benzo[b]thiophen-2-yl-pyridin (btp) main ligands and one 2,2'-biimidazole (H2biim) ancillary ligand are reported: [$(pqx)_2$Ir(biim)]Cl (1), [$(dmpqx)_2$Ir(biim)]Cl (2), [$(dfpqx)_2$Ir(biim)]Cl (3), [$(btp)_2$Ir(biim)]Cl (4). Complex 1 showed a distorted octahedral geometry around the iridium(III) metal ion with cis metallated carbons and trans nitrogen atoms. The absorption, emission and electrochemical properties were systematically evaluated. The complexes exhibited red phosphorescence in the spectral range of 580 to 620 nm with high quantum efficiencies of 0.58 - 0.78 in both solution and solid-state at room temperature depending on the cyclometalated main ligands. The cyclic voltammetry of the complexes (1-3) showed a metal-centered irreversible oxidation in the range of 1.40 to 1.90 V as well as two quasi reversible reduction waves from -1.15 to -1.45 V attributed to the sequential addition of two electrons to the more electron accepting heterocyclic portion of two distinctive cyclometalated main ligands, whereas complex 4 showed a reversible oxidation potential at 1.24 V and irreversible reduction waves at -1.80 V.

• Journal of Powder Materials
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• v.15 no.5
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• pp.399-404
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• 2008

Spray pyrolysis was applied to prepare $M_{3}MgSi_{2}O_{8}:Eu^{2+}$ (M=Ca, Sr, Ba) blue phosphor powder. The library of a Ca-Sr-Ba ternary system was obtained by a combinatorial method combined with the spray pyrolysis in order to optimize the luminescent property under vacuum ultraviolet (VUV) excitation. 10 potential compositions were chosen from the first screening. The emission shifted to longer wavelength as Ca became a dominant element and the emission intensity was greatly reduced in the composition region at which Ba is dominant element. On the base of the first screening result, the second fine tuning was carried out in order to optimize the luminescence intensity under VUV excitation. The optimal composition for the highest luminescence intensity was $(Ca_{1.7},\;Sr_{0.3},\;Ba_{1.0})Si_{2}O_{8}:Eu^{2+}$ which had the color coordinate of (0.152, 0.072) and about 64% emission intensity of $BaMgAl_{10}O_{17}$ (BAM) phosphor.