• Proceedings of the KIEE Conference
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• 2005.11a
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• pp.191-193
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• 2005

This study has investigated the effects of the etching method of a Ti substrate for a metal oxide electrode on the electrochemical characteristics of the electrode. The HCl etching develops a fine and homogeneous roughness on the Ti substrate. Fabrication and material properties of the catalytic oxide electrode, which is known to be so effective to destruct refractory organics in aqueous waste, were studied. A method to enhance the fabrication reproducibility of the oxide electrode was tested for Ru, Zr, Sn oxide on the Ti substrate using SEM, XRD, Cyclic voltammetry.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.181.1-181.1
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• 2014

Supercapacitor is attracting growing attention for a promising energy conversion and storage device because of its desirable electrochemical properties such as rapid charge-discharge rate, high power density and long cycle life. Three-dimensional (3D) metal nanostructure has been widely studied since it can provide efficient charge transport along the 3D network in many device applications. In this work, we fabricated well-ordered 3D nickel (Ni) nanostructures using 3D-arrayed polystyrene nano-opal substrates. We also fabricated half-cell supercapacitors by electrodepositing $RuO_2$ onto these nanostructured Ni current collectors and investigated their morphological and electrochemical properties.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.344-349
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• 2014

$RuO_2$-based high frequency thick-film resistor paste was printed at the speed of 10, 100, 300 mm/sec on the AlN substrate, and then sintered at between 750 and $900^{\circ}C$. The sintered thick films were characterized in terms of printing and sintering conditions. With increasing printing speed, the thickness and roughness of sintered film increased. The resistance of the thick film resistor was reduced by increasing the printing speed from 10 to 100 mm/sec, but did not significantly change at 300 mm/sec speed. With increasing sintering temperature, the surface roughness and thickness of sintered resistor film decreased. The reduction rate was large in case of fast printed resistor. The resistance of the resistor increased up to $800^{\circ}C$ with sintering temperature, but again decreased at the higher sintering temperature.

• Journal of the Korean Chemical Society
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• v.18 no.2
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• pp.132-137
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• 1974

Acid mucopolysaccharides were isolated from nucleus pulposus of whale embryo. The separation of acid mucopolysaccharides was most excellent in $0.03{\%}$ hexamine cobaltic chloride in 0.05 M-sodium acetate buffer solution at pH 4.8. Changes in electrophoretic mobility of acid mucopolysaccharides were observed when the sample solution on top of spacer gel were covered with $40{\%}$ sucrose solution. This effect was not observed by the addition of hexamine cobaltic chloride to the buffer solution.

• Journal of the Korean Vacuum Society
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• v.12 no.S1
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• pp.49-51
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• 2003

Amorphous hydrous ruthenium oxide thin films have attracted much interest owing to the possibility of using this material in electrochemical supercapacitors. Recently, it was found that this material is also electrochromic: during the charging/discharging cycle, the optical transmittance of the thin film is modulated. The physical and chemical origin of this phenomenon is not fully understood yet. In this work, we performed in-situ Raman spectroscopy measurements on amorphous hydrous ruthenium oxide thin films during the charging/discharging cycles. Unambiguous changes in the Raman spectrum were observed as protons were injected or extracted from the thin film. When the samples were annealed to reduce the water content, there is a consistent trend in the Raman spectrum. The origins of the Raman features and their relation to the electrochromic and/or supercapacitor characteristics is discussed.

• Proceedings of the Korean Magnestics Society Conference
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• 2008.12a
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• pp.123.1-123.1
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• 2008

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.3
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• pp.192-197
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• 2016

A novel heteroleptic ruthenium(II) complex bearing a 4-picolinic acid unit as anchoring ligands (trans-dithiocyanato bis(4-picolinic acid)ruthenium(II) (trans-H1)) was synthesized and its chemical structure was identified by $^1H$-NMR, FT-IR and mass spectroscopy. The optical, thermal, electrochemical and dye adsorption properties of trans-H1 dye were investigated and compared with those of the gold standard ruthenium complex, Ru(4,4'-dicarboxy-2,2'-bipyridine)$_2cis(NCS)_2$ (N3). DSSCs based on trans-H1 dyes were examined under the illumination of AM 1.5 G, $100mWcm^{-2}$ and exhibited typical photovoltaic properties with an open-circuit voltage ($V_{OC}$) of 0.46 V, a short-circuit current ($J_{SC}$) of $4.10mA{\cdot}cm^{-2}$, a fill factor (FF) of 60.4%, and a conversion efficiency (PCE) of 1.14%.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.1
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• pp.19-27
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• 2000

The polymer electrolyte membrane fuel cell (PEMFC) system was developed. In order to enhance the performance of membrane electrode assembly (MEA), the transfer printing method of the electrocatalyst layer on membrane was developed. The $H_2/O_2$ single cell with an electrode area of $50cm^2$ was fabricated and tested using 20 wt.% Pt/C as an electrocatalyst and the commercial and hand-made MEA such as Nafion 115, Hanwha, Dow, Flemion T and Gore Select. The 100-cell PEMFC stack with an active electrode area of $300cm^2$ was designed and fabricated using 40 wt.% Pt/C and 30 wt.% Pt-Ru/C as a cathode and anode electrocatalysts, respectively. The performance of PEMFC system was obtained to be 7kW (250A at 28V) and 3.5kW (70A at 50V) at $80^{\circ}C$ by flowing $H_2/air$ and methanol reformed fuel gas/air, respectively.

• Proceedings of the Korean Magnestics Society Conference
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• 2012.05a
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• pp.121-122
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• 2012

Iron-excess gallium ferrite, $Ga_{0.6}Fe_{1.4}O_3$ (GFO), is known to have room-temperature ferromagnetic phases and potentially exhibit ferroelectricity as well [1]. But, leaky polarization-electric field (PE) hysteresis curves of the GFO thin film are hurdle to prove its spontaneous polarization, in other words, ferroelecticity. One of the reasons that the GFO films have leaky PE hysteresis loop is carrier hopping between $Fe^{2+}$ and $Fe^{3+}$ sites due to oxygen deficiency. We focus on reducing conducting current by substituting divalent cations at $Fe^{2+}$ sites. GFO thin films were grown epitaxially along b-axis normal to $SrRuO_3/SrTiO_3$ (111) substrates by pulsed laser deposition. Current density of the ion-substituted GFO thin films was reduced by $10^3$ or more. Ferroelectric properties of the ion-substituted GFO thin films were measured using macroscopic and microscopic schemes. In particular, local ferroelectric properties of the GFO thin films were exhibited and their remnant polarization and piezoelectric d33 coefficient were obtained.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.158.2-158.2
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• 2011

DME is acronym of dimethyl ether, which is spotlighted as an ideal fuel to produce hydrogen due to its high hydrogen/carbon ratio, high energy density and easiness to carry. In this research, we calculated thermodynamic hydrogen (or syngas) yield from DME autothermal reforming and compared to other fuels. The reforming efficiency was about 80% above $700^{\circ}C$. Lower OCR has higher reforming efficiency but, it requires additional heat supply since the reactions are endothermic. SCR has no significant effect on the reforming efficiency. The optimized condition is $700^{\circ}C$, SCR 1.5, OCR 0.45 without additional heat supply. Comparing to other commercial gaseous fuels (methane and propane), DME has higher selectivity of $H_2O$ and $CO_2$ than the others due to the oxygen atom in the molecule. To apply DME autothermal reforming to real system, a proper catalyst is required. Therefore, it is performed the experiment comparing various novel metal catalysts based on CGO. Experiments were performed at calculated condition. The composition of product was measured and reforming efficiency was calculated. The catalysts have similar efficiency at high temperature(${\sim}800^{\circ}C$) but, CGO-Ru has the highest efficiency at low temperature ($600^{\circ}C$).