• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.255.2-255.2
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• 2014

Electrode erosion is indispensable for atmospheric plasma systems, as well as for switching devices, due to the high heat flux transferred from arc plasmas to contacts, but experimental and theoretical works have not identified the characteristic phenomena because of the complex physical processes. Our investigation is concerned with argon free-burning arcs with anode erosion at atmospheric pressure by computational fluid dynamics (CFD) analysis. We are also interested in the energy flux and temperature transferring to the anode with a simplified unified model of arcs and their electrodes. In order to determine two thermodynamic quantities such as temperature and pressure and flow characteristics we have modified Navier-Stokes equations to take into account radiation transport, electrical power input and the electromagnetic driving forces with the relevant Maxwell equations. From the simplified self-consistent solution the energy flux to the anode can be derived.

• Journal of KSNVE
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• v.10 no.6
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• pp.1029-1034
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• 2000

A new electro-rheological squeeze film damper (ER-SFD) has been sealed with slotted piston rings which have electrodes at the inside of the constant gap. The slotted ER-SFD can prevent the problem of electric discharge which might be occurred in the previous configuration of an ER-SFD. The current paper presents the extraction of linearized dynamic coefficients within small orbit where these coefficients are controlled by the application of electric strength. Test rig has been modified to isolate the damper section for dynamic coefficient extraction. The results show that rotordynamic coefficients, damping and inertia terms, increase with increasing supply voltages, while stiffness coefficients decrease with increasing supply voltages. notating speed of rigid shaft does not affect these coefficients.

• Journal of Chest Surgery
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• v.14 no.2
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• pp.168-174
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• 1981

Since cardiac pacemaker was first totally implanted by Chardack, Gage and Greatbatch [1966], the electrical circuity of the cardiac pacemaker has been improved, modified, and refined. The problem of transvenous electrodes, however, is still remained; this may be due to electrode displacement, exit and/or entrance block, lead fracture and insulation defects. In permanent cardiac pacing, Irreversible loss of function of the transvenous electrode catheter eventually requires insertion of new lead. Authors now report one case that disclosed easy displacement of electrode tip in early phase of implantation and then two years and five months later, malfunctioning electrode could not be withdrawn from the cardiovascular system because it has become firmly enclosed by fibrous tissue along its course from the vein tract to the right ventricle. Under such circumstances, the electrode catheter tip was left in tricuspid annulus after being sutured at its entrance and burying the loop of lead in generator pocket. New other one electrode was then reimplantation through left external jugular vein.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.107-110
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• 2002

The electrophoretic deposition (EPD) technique have been applied to fabricating superconducting films and wires in former researches of our Lab. However, the particles of EPD films were usually deposited random1y on the metal substrate, the vertically combined a.c and d.c fields were applied to the EPD electrodes for orienting and densifying the particles of high $T_{c}$ superconducting deposition film on the substrate metal. Therefore, the surface states of EPD films by this combined fields could be oriented and affect to the electric properties increasing of superconducting films. The proposed method modified by a.c. assisted field to the conventional electrophoresis system was suitable to obtain improved properties with particle oriented deposition and densification.

• Macromolecular Research
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• v.9 no.3
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• pp.179-183
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• 2001

Cathode materials for the polymer electrolyte membrane fuel cell was prepared by electropoly-merization of aniline at carbon paper in the presence of copper tetrasulfonato-phthalocyanine (CuTsPc) and their electrocatalytic behavior was studied. The amount of polyaniline and CuTsPc in the carbon paper was determined by UV spectroscopy of residual solution in electrochemical cell. The redox process of the prepared electrodes was investigated with cyclic voltammetry. The highest reversible current density was observed at the electrode that contains 27.6 wt% of polyaniline and 19.7 wt% of CuTsPc. The morphology of composite electrode from SEM showed the presence of large cluster of polyaniline with CuTsPc, which should be more finely interpenetrated into macropores of carbon for the better electrocatalytic activity.

• Journal of Electrochemical Science and Technology
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• v.2 no.1
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• pp.57-61
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• 2011

This paper describes an electrochemical immunoassay for simple, fast and quantitative detection of a urinary hippuric acid which is one of major biological indicator in toluene-exposed humans. The electrochemical system of immunoassay was based on the directly osmium complex conjugated with hippuric acid. With the competition between free hippuric acid (HA) and the osmium-hippuric acid conjugate (Os-HA) to bind with antibody hippuric acid (Anti-HA) coated onto gold nanoparticles, the electrical signals were proportional to urinary hippuric acid (HA) in the range of 0.01-5 mg/mL which is enough range to be used for in-field or point-of-care (POC) diagnosis. The proposed electrochemical method can be extended to the applications to detect a wide range of different small molecules in the field of health care.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.10a
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• pp.211-215
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• 2008

This paper deals with the transient ground impedance of small-sized needle-rod installed in a test field, Impulse voltage generator was used to inject lightning impulse on a ground electrode and modified fall-of potential method was proposed to measure the high ground potential rise. Transient ground impedance was analysed with impedance curve and I-V curve as respects the resistivity of soil. Soil ionization near the ground electrode is activated in high resistivity soil and have an effect on the reduction of transient ground impedance significantly.

• Journal of the Korean Electrochemical Society
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• v.9 no.3
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• pp.113-117
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• 2006

The electrochemical properties of the redox mediator, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) ($ABTS^{2-}$) were studied using cyclic voltammetry. The measured potentials (${E^o}'$ vs SCE) of the two redox couples of ABTS are 0.45 V for $ABTS^{2-}/ABTS^{\cdot-}$ and 0.87 V for $ABTS^{\cdot-}/ABTS^0$. The rate constant for heterogeneous electron transfer and the diffusion coefficients for $ABTS^{2-}$ are $5x10^{-3}cm\;s^{-1}$ and $3.1x10^{-6}cm^2\;s^{-1}$, respectively. Our interest in $ABTS^{2-}$ stems from the fact that this molecule functions as a substrate to the copper oxidase, laccase, by providing the reducing equivalents necessary for the biocatalyzed reduction of dioxygen to water. Consequently, when laccase is tethered to an electrode surface or dissolved in solution, $ABTS^{2-}$ can be used to quantify enzyme activity electrochemically.

• Journal of Sensor Science and Technology
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• v.22 no.5
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• pp.357-363
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• 2013

An ultraviolet pulsed laser ablation of polyimide film coated with platinum has been used to enhance the sensitivity for the application as an electrochemical biosensor. Densely packed cones are formed on polyimide surface after UV irradiation which results in increase of surface area. In order to apply the sensitivity improvement of laser ablated polyimide film electrodes, the glucose oxidase modified biosensor was fabricated by using an encapsulation in the gel matrix through sol-gel transition of tetraethoxysliane on the surface of laser ablated polyimide film. The optimum conditions for glucose determination have been characterized with respect to the applied potential and pH. The linear range and detection limit of glucose detection were from 2.0 mM to 18.0 mM and 0.18 mM, respectively. The sensitivity of glucose biosensors fabricated with laser ablated polyimide film is about three times higher than that of plain polyimide film due to increase in surface area by laser ablation.

• Bulletin of the Korean Chemical Society
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• v.11 no.2
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• pp.124-126
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• 1990

The potentiometric response behavior of a polypyrrole(PPy) coated Pt electrode to nitrate ion has been studied. The electrode shows a nernstian behavior with a slope of 59 mV over 0.50 M to $1.0{\times}10^{-3}M\;NO_3\;^-$ and a detection limit of $1.0{\times}10^{-4}M\;NO_3\;^-$. The response of the electrode is fast and the selectivities for $I^-,\;ClO_4\;^-,\;and\;IO_4\;^-$ are found to be improved. The effect of pH on the potential response to $NO_3\;^-$ is compared with the existing nitrate ion selective electrodes.