• Journal of Sensor Science and Technology
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• v.27 no.4
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• pp.249-253
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• 2018

Infrared transparent ZnS ceramics were synthesized through hydrothermal synthesis ($180^{\circ}C$, 70 h) and sintered using a hot press process at $750^{\circ}C-1000^{\circ}C$. We carried out x-ray diffraction, scanning electron microscopy, and Fourier transform-infrared spectroscopy to confirm the optical properties of the ZnS ceramics after sintering at various temperatures. The phase of ZnS nanopowders was a single phase (cubic) without the hexagonal phase. However, as sintering temperature increased, the formation and increment of hexagonal structures was confirmed. The ZnS ceramic sintered at a temperature of $750^{\circ}C$ showed poor transmittance because it was not completely sintered and because of the pore effect. The ZnS ceramic with the highest transmittance (approximately 69%) was sintered at $800^{\circ}C$. As sintering temperature increased, transmittance gradually decreased owing to the increase in the formation of the hexagonal phase.

• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.18-18
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• 1998

• Journal of Photoscience
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• v.10 no.2
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• pp.209-214
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• 2003

A series of coupled-hemicyanine dyes with alkylene spacer were successfully synthesized by a reaction of coupled aldehydes with corresponding salts, respectively. These coupled dyes had more excellent thermal properties (high decomposition temperature, stiff decomposition behavior) and higher molar absorption properties than an uncoupled dye. The coupled dyes with perchlorate anions showed the strongest exothermic decomposition while those with hexafluorophosphorate anions showed endothermic decomposition. As the coupling length (n=3, 4, 5, 6) increased, thermal properties decreased and dyes with even spacer was more thermally stable than dyes with odd spacer. Among several coupled dyes, C4-NP-ClO4 and C4-Cl-ClO4 exhibited the best recording properties with the lowest jitter value of 7.5∼9.5% in authoring disc.

• Korean Journal of Materials Research
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• v.33 no.10
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• pp.414-421
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• 2023

Infrared radiation (IR) refers to the region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1 mm. Any object with a temperature above absolute zero (0 K) radiates in the infrared region, and a material that transmits radiant energy in the range of 0.74 to 1.4 um is referred to as a near-infrared optical material. Germanate-based glass is attracting attention as a glass material for infrared optical lenses because of its simple manufacturing process. With the recent development of the glass molding press (GMP) process, thermal imaging cameras using oxide-based infrared lenses can be easily mass-produced, expanding their uses. To improve the mechanical and optical properties of commercial materials consisting of ternary systems, germanate-based heavy metal oxide glasses were prepared using a melt-cooling method. The fabricated samples were evaluated for thermal, structural, and optical properties using DSC, XRD, and XRF, respectively. To derive a composition with high glass stability for lens applications, ZnO and Sb₂O₃ were substituted at 0, 1, 2, 3, and 4 mol%. The glass with 1 mol% added Sb₂O₃ was confirmed to have the optimal conditions, with an optical transmittance of 80 % or more, a glass transition temperature of 660 ℃, a refractive index of 1.810, and a Vickers hardness of 558. The possibility of its application as an alternative infrared lens material to existing commercial materials capable of GMP processing was confirmed.

• Transactions on Electrical and Electronic Materials
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• v.17 no.2
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• pp.121-124
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• 2016

ZnSnO₃ (ZTO)/Ag/ ZnSnO₃ (ZTO) trilayer films were prepared on glass substrates by radio frequency (RF) and direct current (DC) magnetron sputtering. The electrical resistivity and optical transmittance of the films were investigated as a function of the Ag interlayer thickness. ZTO films with a 15 nm thick Ag interlayer show the highest average visible transmittance (83.2%) in the visible range. In this study, the highest figure of merit (2.1×10⁻² Ω cm) is obtained with the ZTO 50 nm/Ag 15 nm/ZTO 50 nm films. The enhanced optical and electrical properties of ZTO films with a 15 nm thick Ag interlayer are attributed to the crystallization of the Ag interlayer, as supported by the distinct XRD pattern of the Ag (111) peaks. From the observed results, higher optical and electrical performance of the ZTO film with a 15 nm thick Ag interlayer seems to make a promising alternative to conventional transparent conductive ITO films.

• Macromolecular Research
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• v.16 no.5
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• pp.385-395
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• 2008

Synthesis and properties of novel excited-state intramolecular proton transfer (ESIPT) materials, recently developed in our group, are described. Highly efficient ESIPT reaction, achieved in polyquinolines, polybenzoxazoles, and oxadiazole and imidazole derivatives possessing an intramolecular tautomerizable hydrogen bond, has been investigated theoretically and experimentally. It is demonstrated that unique properties arising from the ESIPT process (large Stokes' shift, no self-absorption, and easy population inversion, etc.) make it possible to produce advanced polymer devices for lasing, optical storage, and electroluminescence.

• Journal of the Korean Society for Heat Treatment
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• v.29 no.5
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• pp.216-219
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• 2016

$SnO_2$ single layer films (100 nm thick) and 2 nm thick Ni intermediated $SnO_2$ films were deposited on glass substrate by RF and DC magnetron sputtering without intentional substrate heating and then the influence of the Ni interlayer on the electrical and optical properties of the films were investigated. As deposited $SnO_2$ single layer films show the optical transmittance of 82.6% in the visible wavelength region and a resistivity of $6.6{ \times}10^{-3}{\Omega}cm$, while $SnO_2/Ni/SnO_2$ trilayer films show a lower resistivity of $2.7{ \times}10^{-3}{\Omega}cm$ and an optical transmittance of 76.3% in this study. Based on the figure of merit, it can be concluded that the intermediate Ni thin film effectively enhances the opto-electrical performance of $SnO_2$ films for use as transparent conducting oxides in flexible display applications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.535-536
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• 2006

Researches about micro technology travel lively in these days. Such many researches are concentrated in the field of materials and a process field. But properties of micro materials should be known to give results of research developed into still more. In these various material properties, reliability data such as mechanical, optical, thermal property, etc is the basic property. In this paper, it is measured that is material properties of main BLU(Back Light Unit) components in LCD(Liquid Crystal Display). The pattern shape of prism sheet, diffuser film and reflective plate are measured by variable 3D scanning equipments. It is researched which is the method to measure an optimal 3D pattern shape in each components.

• Proceedings of the Materials Research Society of Korea Conference
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• 2001.11a
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• pp.158-158
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• 2001

• Transactions of the Society of Information Storage Systems
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• v.1 no.1
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• pp.93-98
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• 2005

Rewritable optical disk is one of the essential data storage media in these days, which takes advantage of the different optical properties in the amorphous and crystalline states of phase change materials. As well known, data transfer rate is one of the most important parameter of the phase change optical disks, which is mostly limited by the crystallization speed of recording media. Therefore, we doped Sn/Bi to $Ge_2Sb_2Te_5$ alloy in order to improve the crystallization speed and investigated the dependence of phase change characteristics on Sn/Bi doping concentration. The Sn/Bi doped $Ge_2Sb_2Te_5$ thin film was deposited by RF magnetron co-sputtering system and phase change characteristics were investigated by X-ray diffraction (XRD), static tester, UV-visible spectrophotometer, electron probe microanalysis (EPMA), inductively coupled plasma mass spectrometer (ICP-MS) and atomic force microscopy (AFM). Optimum doping concentration of Bi and Sn were 5${\~}$6 at.$\%$ and the minimum time for crystallization was below than 20 ns. This improvement is correlated with the simple crystalline structure of Sn/Bi doped $Ge_2Sb_2Te_5$ and the reduced activation barrier arising from Sn/Bi doping. The results indicate that Sn/Bi might play an important role in the transformation kinetics of phase change materials..