Gwangju, South Korea
Gwangju, South Korea

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Kang B.-M.,Chonnam National University | Lim Y.-S.,Chonnam National University | Jeong W.-J.,OT and T Inc. | Kang B.-W.,Gwangju University | Ahn H.-G.,Sunchon National University
Transactions on Electrical and Electronic Materials | Year: 2014

We deposited TiAgN and ZrAgN nanocomposite coatings on pure Titanium specimens, by using arc ion plating (AIP) with single alloy targets. TiAg ZrAg alloy targets of 5 wt.%, 10 wt.% silver content by vacuum arc remelting (VAR), followed by homogenization for 2 hours at 1,100℃ in non-active Ar gas atmosphere and characterized these samples for morphology and chemical composition. We investigated the biocompatibility of TiAg and ZrAg alloys by examining the proliferation of L929 fibroblast cells by MTT test assay, after culturing the cells (4×104 cells/cm2) for 24 hours; and exploring the antibacterial properties of thin films by culturing Streptococus Mutans (KCTC3065), using paper disk techniques. Our results showed no cytotoxic effects in any of the specimens, but the antibacterial effects against Streptococus Mutans appeared only in the 10 wt.% silver content specimens. ©2014 KIEEME. All rights reserved.


Kang B.-M.,Chonnam National University | Jeong W.-J.,OT and T Inc. | Park G.-C.,Mokpo National University | Yoon D.-J.,Sunchon National University | And 2 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2015

In this work, we found the characteristics of an antibacterial TiAgN thin film coated on the pure titanium specimen via the physical vapor deposition process (PVD). TiAgN thin films were coated using TiAg alloy targets by arc ion plating method. Changing the process parameters, the surface analysis of TiAgN thin film was observed by FE-SEM and the force of adhesion was measured with Scratch Tester. The proliferation of human gingival fibroblast (HGF) cells was examined by XTT test assay and the antibacterial properties were investigated by culturing Streptococus Mutans (KCTC 3065) using paper disk technques. At the result of experiment, cytotoxic effects were not found and the antibacterial effects against Streptococus Mutans were appeared over 5 wt% TiAgN specimens. Copyright © 2015 American Scientific Publishers All rights reserved.


Park C-M.,Sunchon National University | Seo H-S.,Sunchon National University | Cho J-H.,Sunchon National University | Choi D-H.,Sunchon National University | And 6 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2013

In order to reutilize the spent metallic titanium chips, TiO2 photocatalysts were prepared using the self-propagating high-temperature synthesis (SHS) method, and were characterized by N2 gas adsorption, X-ray diffraction, and scanning electron microscope, particle size distribution. Also, their photocatalytic activities were evaluated using methylene blue as a model organic compound. It was confirmed that the crystal structure of TiO2 prepared by SHS method was relatively homogeneous powder of rutile type. Optimum conditions for photocatalytic degradation of methylene blue under UV-C irradiation were methylene blue 9.5 ppm in solution and at amount of TiO 2 added of 0.02 g/L. In addition, it was found that the photocatalytic activity for methylene blue degradation over the prepared TiO2 particles was positively related with BET specific surface area. Copyright © 2013 American Scientific Publishers All rights reserved.


Kim R.,University of Dayton | Kang B.-M.,Gwangju University | Jeong W.-J.,OT and T Inc. | Jung Y.-J.,Mokpo National University | And 6 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2016

A hybrid and etchless electrooptic (EO) polymer waveguide modulator based on both a photobleaching- induced optical waveguide (PBOW) and a strain-induced optical waveguide (SIOW) is described. The SIOW is defined by a metal strip line stressor deposited on top of the upper cladding that introduces the refractive index change within the core region. The PBOW technique is used to form an optical waveguide which is based on a photo-bleaching process, known as a photo-oxidation that is an irreversible decomposition of EO material, resulting in a permanent decrease in index of refraction. It is shown that this proposed fabrication idea combining two etchless techniques can be applicable to a wide range of polymer photonic integrated circuits. Preliminary results obtained from fabricated devices reveal that their half-wave voltage are ranging from 8 V to 10 V, their extinction ratio exhibits more than 15 dB, and the fiber-to-waveguide-to-lens loss is estimated to be ∼9.5 dB for TM polarization at 1.55 μm wavelength in the active interaction of ∼1.5 cm long. Copyright © 2016 American Scientific Publishers All rights reserved.


Baek M.-S.,Sunchon National University | Yoon D.-J.,Sunchon National University | Kang B.-M.,OT and T Inc. | Jeong W.-J.,OT and T Inc. | Kim B.-I.,Sunchon National University
Korean Journal of Materials Research | Year: 2015

The implanting of metal products is performed with numerous surface treatments because of toxicity and adhesion. Recently, the surface modification of metal products has been actively studied by coating the surface of the TiC or TiN film. We prepared a Ti(10%)Ag Target which may be used in dental oral material by, using the AIP(arc ion plating) system TiAgN coating layer that was deposited on Ti g.23. The purpose of this study was to establish the optimal bias voltage conditions of the coated TiAgN layer formed by the AIP process. The TiAgN coatings were prepared with different bias voltage parameters (0V to -500V) to investigate the effect of bias voltage on their mechanical and chemical properties. The SEM(scanning electron microscope), EDS(energy dispersive X-ray spectrometer), XRD(X-ray diffraction), micro-hardness, and potentiodynamic polarization were measured and the surface characteristics of the TiAgN coating layers were evaluated. The TiAgN coating layer had different mechanical characteristics based on the bias voltage, which also showed differences in thickness and composition. © Materials Research Society of Korea.


Ahn H.-G.,Sunchon National University | Lee H.-G.,Sunchon National University | Chung M.-C.,Sunchon National University | Park K.-P.,Sunchon National University | And 5 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2016

In this study, titanium chips (TC) generated from industrial facilities was utilized as TiO2 support for hydrogenation of carbon dioxide (CO2) to methyl alcohol (CH3OH) over Cu-based catalysts. Nanosized CuO and ZnO catalysts were deposited on TiO2 support using a co-precipitation (CP) method (CuO-ZnO/TiO2), where the thermal treatment of TC and the particle size of TiO2 are optimized on CO2 conversion under different reaction temperature and contact time. Direct hydrogenation of CO2 to CH3OH over CuO-ZnO/TiO2 catalysts was achieved and the maximum selectivity (22%) and yield (18.2%) of CH3OH were obtained in the range of reaction temperature 210∼240 °C under the 30 bar. The selectivity was readily increased by increasing the flow rate, which does not affect much to the CO2 conversion and CH3OH yield. Copyright © 2016 American Scientific Publishers All rights reserved .


Lee H.-G.,Sunchon National University | Ahn W.-J.,Sunchon National University | Kim S.-K.,Sunchon National University | Kang B.-M.,OT and T INC. | And 3 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2015

The TiO2 powder was prepared from the spent titanium chips by applying the sol-gel method with neutralization by NaOH solution. The prepared TiO2 powder was characterized using a particle size analysis, BET surface area, and XRD analysis. The crystal structure of the TiO2 powder was rutile type, and the powder was obtained to be nanosized. BET surface area of TiO2 powder was 118 m2/g, average particle size was 266.5 nm. The photocatalytic property of the TiO2 powder was evaluated as decomposition rate of methylene blue (MB) by using a liquid phase stirred reactor. Decomposition rate on TiO2 powder (P-25) was 1.5 times higher than that of the prepared TiO2 powder. Decomposition rate on the prepared TiO2 powder was linearly increased with increasing the amount of TiO2 powder, and approached to a specific value. MB concentration and decomposition rate was not correlated within the experimental range. The maximum value of decomposition rate at about pH 8 was 62%. Copyright © 2015 American Scientific Publishers All rights reserved.


Lee H.-G.,Sunchon National University | Lee Y.-H.,Sunchon National University | Yun H.-J.,Sunchon National University | Jo J.-H.,Sunchon National University | And 9 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2016

The TiO2 powder was prepared from the spent titanium chips by applying the sol-gel method. The spent titanium chip was dissolved in HCl solution, and then NH4OH solution was added. The molar concentration of NH4OH solution was 2 M, 4 M, 8 M, and 10 M. Obtained TiO2 powders were calcined at 200°C, 400°C, and 600°C. The prepared TiO2 powder was characterized using a particle size analysis, BET surface area, and XRD analysis. The crystal structure of the TiO2 powder was rutile type and anatase. The highest BET surface area of TiO2 powder was 432.8 m2/g. The photocatalytic property of the TiO2 powder was evaluated as decomposition rate of methylene blue(MB) by using a liquid phase stirred reactor. UV source was a UV-A, and concentration of MB in most experiments was 8 ppm. The concentration of MB was measured by absorbance at 664 nm using UV spectroscopy. Photocatalytic efficiency of prepared TiO2 powder depended highly on concentration of NH4OH solution. The TiO2 powder prepared with 8 M-NH4OH solution showed the highest efficiency, the decomposition efficiency at decomposition time of 2 hr and MB concentration of pH 8 was 98%. Copyright © 2016 American Scientific Publishers. All rights reserved.


Kang S.-J.,Sunchon National University | Kim K.-J.,Sunchon National University | Chung M.-C.,Sunchon National University | Jung S.-C.,Sunchon National University | And 4 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2011

Nanosized TiO 2 thin film on the substrate such as stainless steel plate and slide glass film were prepared by magnetron sputtering method, and these TiO 2 thin films were characterized by field emission-scanning electron microscopy (FE-SEM). Photocatalytic activity for Methyl-ethyl-ketone (MEK) and acetaldehyde were measured using a closed circulating reaction system through the various ultra violet (UV) sources. From the results of SEM images, nanosized TiO 2 thin film was uniformly coated on slide glass, ranging from 360 nm to 370 nm. Photocatalytic activity of MEK over TiO2 thin film on stainless steel plate did not occur by UV-A irradiation, but was efficiently decomposed by UV-B and UV-C. Also, acetaldehyde could be decomposed than MEK. The effect of sputtering conditions on their structure and photocatalytic activities were investigated in detail. Copyright © 2011 American Scientific Publishers All rights reserved.


Kim K.-J.,Sunchon National University | Song J.-K.,Sunchon National University | Shin S.-S.,Sunchon National University | Kang S.-J.,Sunchon National University | And 4 more authors.
Journal of Nanoscience and Nanotechnology | Year: 2011

Gold catalysts supported on Co 3O 4 were prepared by co-precipitation (CP), deposition-precipitation (DP), and impregnation (IMP) methods. The Au/Co 3O 4 catalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (TPR) to understand the different activities for CO oxidation with different preparation methods. Gold particles below 5 nm supported on Co 3O 4 by DP method were found to be more exposed to the surface than those by CP and IMP methods, and this catalyst was highly active and stable in CO oxidation. Finally, catalytic activity of Au/Co 3O 4 catalyst for CO oxidation was strongly dependent on the gold particle size. Copyright © 2011 American Scientific Publishers All rights reserved.

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