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Pohang, South Korea

Kim Y.S.,Kyung Hee UniversityGyeonggi do | Khatiwoda P.,University of Minnesota | Park B.H.,Pusan National University | Lee H.Y.,University of Minnesota
Social Work in Public Health | Year: 2016

Existing studies report a negative association between health literacy and hospital/emergency room use. Despite substantial research on this topic among older Americans, little is known about the link between health literacy and healthcare services use among older Koreans. This study investigates this link, using a sample of 596 adults, 65 and older, from Korea's three largest cities. Andersen's behavior model guided the study. Findings revealed that participants with higher health literacy were significantly less likely to use emergent health services. Enhanced health literacy will likely promote better health outcomes for older Koreans and reduce Korea's healthcare costs. © 2016 Taylor & Francis Group, LLC. Source

Kim J.-H.,Korea University | Kim D.-H.,Korea University | Kim S.-K.,Kyung Hee UniversityGyeonggi do | Yoo Y.-Z.,Duksan Hi metal Co. | Seong T.-Y.,Korea University
Ceramics International | Year: 2016

We modified the refractive index (n) of TiO2 by annealing at various temperatures to obtain a high figure of merit (FOM) for TiO2/Ag/TiO2 (45 nm/17 nm/45 nm) multilayer films deposited on glass substrates. Unlike the as-deposited and 300 °C-annealed TiO2 films, the 600 °C-annealed sample was crystallized in the anatase phase. The as-deposited TiO2/Ag/as-deposited TiO2 multilayer film exhibited a transmittance of 94.6% at 550 nm, whereas that of the as-deposited TiO2/Ag/600 °C-annealed TiO2 (lower) multilayer film was 96.6%. At 550 nm, n increased from 2.293 to 2.336 with increasing temperature. The carrier concentration, mobility, and sheet resistance varied with increasing annealing temperature. The samples exhibited smooth surfaces with a root-mean-square roughness of 0.37–1.09 nm. The 600 °C-annealed multilayer yielded the highest Haacke's FOM of 193.9×10−3 Ω−1. © 2016 Elsevier Ltd and Techna Group S.r.l. Source

Lee H.-K.,Kyung Hee UniversityGyeonggi do | Na J.-Y.,Kyung Hee UniversityGyeonggi do | Moon Y.-J.,Kyung Hee UniversityGyeonggi do | Seong T.-Y.,Korea University | Kim S.-K.,Kyung Hee UniversityGyeonggi do
Current Applied Physics | Year: 2015

We designed a near-unity transmittance dielectric/Ag/ITO electrode for high-efficiency GaN-based light-emitting diodes by using the scattering matrix method. The transmittance of an ultrathin metal layer, sandwiched between a dielectric layer and an ITO layer, was investigated as a function of the thickness and the optical constant of each constituent layer. Three different metals (Ag, Au, and Al) were examined as the metal layer. The analytical simulation indicated that the transmittance of a dielectric/metal/ITO multilayer film is maximized with an approximately 10-nm-thick Ag layer. Additionally, the transmittance also tends to increase as the refractive index of the upper dielectric layer increases. By tailoring the thickness of the dielectric layer and the ITO layer, the dielectric/Ag/ITO structure yielded a transmittance of 0.97, which surpasses the maximum transmittance (0.91) of a single ITO film. Furthermore, this extraordinary transmittance was present for other visible wavelengths of light, including violet and green colors. A complex phasor diagram model confirmed that the transmittance of the dielectric/metal/ITO multilayer film is influenced by the interference of reflected partial waves. These numerical findings underpin a rational design principle for metal-based multilayer films that are utilized as transparent electrodes for the development of efficient light-emitting diodes and solar cell devices. © 2015 Elsevier B.V.All rights reserved. Source

Hwang I.Y.,Kyung Hee UniversityGyeonggi do | Lee S.H.,Korea Research Institute of Chemical Technology | Choi Y.S.,Chungnam National University | Park S.J.,Myongji UniversityGyeonggido | And 7 more authors.
Journal of Microbiology and Biotechnology | Year: 2014

Methane is considered as a next-generation carbon feedstock owing to the vast reserves of natural and shale gas. Methane can be converted to methanol by various methods, which in turn can be used as a starting chemical for the production of value-added chemicals using existing chemical conversion processes. Methane monooxygenase is the key enzyme that catalyzes the addition of oxygen to methane. Methanotrophic bacteria can transform methane to methanol by inhibiting methanol dehydrogenase. In this paper, we review the recent progress made on the biocatalytic conversion of methane to methanol as a key step for methane-based refinery systems and discuss future prospects for this technology. © 2014 by The Korean Society for Microbiology and Biotechnology. Source

Hwang I.Y.,Kyung Hee UniversityGyeonggi do | Hoon Hur D.,Kyung Hee UniversityGyeonggi do | Hoon Lee J.,Kyung Hee UniversityGyeonggi do | Park C.-H.,Kyung Hee UniversityGyeonggi do | And 3 more authors.
Journal of Microbiology and Biotechnology | Year: 2015

Recently, methane has attracted much attention as an alternative carbon feedstock since it is the major component of abundant shale and natural gas. In this work, we produced methanol from methane using whole cells of Methylosinus trichosporium OB3b as the biocatalyst. M. trichosporium OB3b was cultured on NMS medium with a supply of 7:3 air/methane ratio at 30oC. The optimal concentrations of various methanol dehydrogenase inhibitors such as potassium phosphate and EDTA were determined to be 100 and 0.5 mM, respectively, for an efficient production of methanol. Sodium formate (40 mM) as a reducing power source was added to enhance the conversion efficiency. A productivity of 49.0 mg/l·h, titer of 0.393 g methanol/l, and conversion of 73.8% (mol methanol/mol methane) were obtained under the optimized batch condition. © 2015 by The Korean Society for Microbiology and Biotechnology. Source

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