• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.2
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• pp.133-137
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• 2014

The recent development of electro-optic devices and anticorrosion media has made it necessary investigate infrared optical systems with solid-solid interfaces of materials with amorphous characteristics. One of the most promising classes of materials for these purposes seems to be chalcogenide glasses, which are based on the Ge_Sb_Se system, have drawn much attention because of their use in preparing optical lenses and fibers that are transparent in the range of 3-12 um. In this study, a standard melt-quenching technique was used to prepare amorphous Ge_Sb_Sechalcogenideto be used in the design and manufacture of infrared optical products. The results of structural, optical, and surface roughness analyses of high purity Ge_Sb_Sechalcogenide glasses after various annealing processes reported.

• Korean Journal of Materials Research
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• v.26 no.11
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• pp.598-603
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• 2016

The recent development of electro-optic devices and anticorrosion media has led to the necessity to investigate infrared optical systems with solid-solid interfaces of materials that often have the characteristic of amorphousness. One of the most promising classes of materials for those purposes seems to be the chalcogenide glasses. Chalcogenide glasses, based on the Ge-Sb-Se system, have drawn a great deal of attention because of their use in preparing optical lenses and transparent fibers in the range of 3~12 um. In this study, amorphous Ge-Sb-Se chalcogenide for application in an infrared optical product design and manufacture was prepared by a standard melt-quenching technique. The results of the structural, optical and surface roughness analysis of high purity Ge-Sb-Se chalcogenide glasses are reported after various annealing processes.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.236-243
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• 2018

A series of $Er^{3+}/Yb^{3+}$ co-doped fluorophosphate glasses with varying $YbF_3$ concentration were prepared by a high temperature melt quenching technique. Absorption and emission cross-sections were determined by using the McCumber theory. The larger emission cross-section ($9.86{\times}10^{-21}cm^2$) and longer fluorescence lifetime (12.37 ms) were obtained for the $^4I_{13/2}{\rightarrow}^4I_{15/2}$ transition of ABS3Er4Yb glass. The sensitivity and temperature of the maximum sensitivity were evaluated by the fluorescence intensity ratio method from the measured upconversion spectra. The results were discussed and compared to the other reported glasses.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.55-55
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• 2003

Recently, with the rapid development of the waveguide division multiplexing (WDM) systems for large capacity and flexibility of information network, the broad band 1.5$\mu\textrm{m}$ erbium-doped waveguide amplifier (EDWA) become important. The main factors affecting the performance of sol-gel-based waveguides are non-radiative relaxation channels due to rare-earth concentration quenching and to vibration of the OH groups Therefore, the sol-gel process has to be carefully controlled in order to minimize the residual OH content.

• Journal of Integrative Natural Science
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• v.2 no.3
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• pp.215-218
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• 2009

A silaspirotropylidene has been obtained from the reaction of the lithium salt of tetraphenylsilole dianion with 2 equiv of diphenylcyclopropene, followed by quenching with Me3SiCl. Silaspirotropylidene exhibits an unusual optical property its optical property was characterized by UV-vis and fluorescence spectroscopy. Absorption wavelength maxima of silaspirotropylidene was 420 nm. silaspirotropylidene displayed an emission band at 550 nm with excitation wavelength of 420 nm.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.11a
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• pp.21-23
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• 1994

By adding La₂O₃ to optical multicomponent glass composition, after making mother glass and core fiber that enable to enlarge the infrared transmittance region, then surveyed the optical properties. Through thermal analysis of the glass abstained by melt-quenching after selecting stable basic composition on devitrification and replace SiO₂ by 4-12wt% La₂O₃. As La₂O₃ increases up to l2wt% transition temperature, refractive index, density, deformation temperature increased, whereas thermal expansion coefficient decreased. As a result of inspectig transmittance in UV/VIS/IR region, visable region indicated the decrease of transmittance by increasing the La₂O₃ and transmittance region was enlarged by increasing the La₂O₃ in IR region. Also, fabricate core fiber at 820℃ and severy the optical loss we could fact that La₂O₃ composition added 12wt% showed the minimum optical loss.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.26 no.2
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• pp.80-83
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• 2016

In the present paper, garnet structured $Y_3Al_5O_{12}:Ce^{3+}$ (YAG : Ce) ceramic phosphor plate (CPP) for high power laser diode (LD) was prepared and optical properties were analyzed. We synthesized monodispersed spherical nano-sized YAG : Ce particles by liquid phase method, fabricated phosphor ceramic plate with the addition of $Al_2O_3$. $75{\mu}m$ and $100{\mu}m$ thick YAG : Ce CPPs were compared in terms of the factors of conversion efficacy, thermal quenching, luminance and correlated color temperature (CCT). In conclusion, conversion efficacy decreased by 25 % in both samples and $100{\mu}m$ thick sample provides better optical properties of thermal quenching, maximum light conversion efficacy and maximum luminance value.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.47.2-47.2
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• 2015

At local, galaxy properties are well known to be clearly different in different environments. However, it is still an open question how this environment-dependent trend has been shaped. In this presentation, we will show the results of our investigation about the evolution of star-formation properties of galaxies over a wide redshift range, from z~2 to z~0.5, focusing its dependence on their stellar mass and environment. In the UKIDSS/UDS region, we estimated photometric redshifts and stellar population properties, such as stellar masses and star-formation rates, using the deep optical and near-infrared data available in this field. Then, we identified galaxy cluster candidates at z~0.5-2. Through the analysis and comparison of star-formation (SF) properties of galaxies in clusters and in field, we found interesting results regarding the evolution of SF properties of galaxies: (1) regardless of redshifts, stellar mass is a key parameter controlling quenching of star formation in galaxies; (2) At z<1, environmental effects become important at quenching star formation regardless of stellar mass of galaxies; and (3) However, the result of the environmental quenching is prominent only for low mass galaxies (M* < $10^{10}M_{\odot}$) since the star formation in most of high mass galaxies are already quenched at z > 1.

• Korean Journal of Materials Research
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• v.9 no.1
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• pp.104-107
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• 1999

We investigated the effects of cooling condition on deep levels and iron precipitate formation in iron-contaminated p-type silicon by DLTS(Deep Level Transient Spectroscopy) and preferential etching technique. Dependency of cooling condition on Bulk Micro-Defect (BMD) and four different iron-related deep traps were observed. For normal cooling condition, T1, T2, T3, T4 traps that related to Fe\ulcorner or Fe-O complex were obtained. However, the trap with activation energy, 0.4 eV was observed for slow cooling condition. The trap caused by the $\textrm{Fe}^{+}\textrm{}^{-}$ pair (H4:0.56eV) were detected only at the case of $\textrm{LN}_{2}$ quenching condition.

• Journal of the Korean Vacuum Society
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• v.7 no.s1
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• pp.1-6
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• 1998

The influence of the order-disorder structural transition on the magnetic and mageto-optical, and transport properties of Fe-Al and Co-Al alloy films has been investigated. The disordered states in the alloy films were prepared by vapor quenching deposition on glass substrates cooled by liquid nitrogen. The experimental study of the magento-optical properties of the ordered and disordered Fe-Al and Co-Al alloy films has been carried out in 1.05-5.0 eV energy range at room temperature. The transport properties have been measured in 2-300K temperature range with and without magnetic field of 0.5T. The influence of the order-disorder structural transition on the magnetic and magneto-optical properties was discussed by using the effective medium approximation and the structural defect approach. That on the temperature dependence of the resistivity was analyzed in a framework of the partial localization of the electronic states and the variable range hopping conductivity.