• Journal of Welding and Joining
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• v.35 no.2
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• pp.52-57
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• 2017

In this study, resistance spot weldability of lightweight steel with high Al contents was evaluated using various electrode shapes. The six types of electrode shape were prepared with different electrode face diameter and radius. The tensile shear tests were carried out to investigate the failure behaviors. Also, the nugget size and hardness were measured and compared with various electrode shapes. The experimental results show that the acceptable weld current region for low density lightweight steel could be obtained with 10mm electrode face diameter and 76mm electrode face radius.

• Journal of the Korean institute of surface engineering
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• v.52 no.3
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• pp.150-155
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• 2019

The carbon electrode was modified through manganese-catalyzed hydrogenation method for high energy density vanadium redox flow battery (VRFB). During the catalytic hydrogenation, the manganese oxide deposited at the surface of the carbon electrode stimulated the conversion reaction from carbon to methane gas. This reaction causes the penetration of the manganese and excavates a number of cavities at electrode surface, which increases the electrochemical activity by inducing additional electrochemically active site. The formation of the porous surface was confirmed by the scanning electron microscopy (SEM) images. Finally, the electrochemical performance test of the electrode with the porous surface showed lower polarization and high reversibility in the cathodic reaction compared to the conventional electrode.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.10
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• pp.814-819
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• 2010

Porous carbon electrodes with wooden materials are manufactured by molding carbonized wood powder. Electrical properties of the interface for electrolyte and porous carbon electrode are investigated from viewpoint of NaCl electrolyte concentration, capacitance and complex impedance. Density of porous carbon materials is 0.47~0.61 g/$cm^3$. NaCl electrolytic absorptance of the porous carbon materials is 5~30%. As the electrolyte concentration increased, capacitance is increased and electric resistance is decrease with electric double layer effect of the interface. The electric current of the porous carbon electrode compared in the copper and the high density carbon electrode was improved on a large scale, due to a increase in surface area. The circuit current increased as the distance between of the porous carbon electrode and the zinc electrode decreased, due to increase in electric field. Experimental results indicated that the current properties of galvanic cell could be improved by using porous carbon electrode.

• Journal of Information Display
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• v.11 no.4
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• pp.149-153
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• 2010

To improve the luminescence characteristics of high-efficiency alternating-current plasma display panels (AC-PDPs), we developed a new hoof-type electrode structure, and we studied the spatiotemporal behavior of the density of the excited Xenon atom in the $1s_5$ metastable state via laser absorption spectroscopy. Using this structure, the maximum density of the excited Xenon atom per cell was improved by 2.4 times that when the conventional electrode structure was used.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1510-1515
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• 2004

The effects of additive ions on the generation of metallic nanoparticles were evaluated using a corona induced supersonic nozzle. Applying the corona discharge to the nanoparticle generator, a tungsten needle and the supersonic nozzle are used as an anode electrode and a cathode electrode respectively. The corona ions act as nuclei for the silver vapor condensation. The ion density was controlled precisely as varying the applied voltage between electrode and nozzle. The mean diameter of the silver particle decreases as the ion density increases. However, the number concentration of the silver particle tended to increase with the ion density. The size distribution is more uniform as the ion density increases.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.6-10
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• 2020

The silver nanowires (AgNWs) were synthesized by the conventional polyol process, which revealed 25 ㎛ and 30 nm of average length and diameter, respectively. The synthesized AgNWs were applied to the CdSe/CdZnS quantum dot (QD) based transparent light-emitting device (LED). The device using a randomly networked AgNWs electrode had some problems such as the high threshold voltage (for operating the device) due to the random pores from the networked AgNWs. As a method of improvement, a composite electrode was formed by overlaying the ZnO:Ga on the AgNWs network. The device used the composite electrode revealed a low threshold voltage (4.4 Vth) and high current density compared to the AgNWs only electrode device. The brightness and current density of the device using composite electrode were 55.57 cd/㎡ and 41.54 mA/㎠ at the operating voltage of 12.8 V, respectively, while the brightness and current density of the device using (single) AgNWs only were 1.71 cd/㎡ and 2.05 mA/㎠ at the same operating voltage. The transmittance of the device revealed 65 % in a range of visible light. Besides the reliability of the devices was confirmed that the device using the composite electrode revealed 2 times longer lifetime than that of the AgNWs only electrode device.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.5
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• pp.460-467
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• 2002

This paper deals with the distribution characteristics of the current density and axial magnetic flux density on the vacuum interrupter with axial magnetic field type using 3 dimension finite element analysis. An axial magnetic field parallel to the current flow in the arc column can improve the current breaking capacity of vacuum interrupter by affecting the arc mode. The axial magnetic flux density on the contact electrode surface is analyzed by inputting external current as a function of the transient time for sine half wave. And it also is analyzed within the gap distance of the contact electrode. The peak value of current but is decreased with the descending current on the contact electrode surface and within the gap distance of the contact electrode. The residual magnetic field is generated on the contact electrode surface and within the gap distance in the instant of zero current, which is due to the influence of eddy currents. The phase shift due to eddy currents, defined as time difference between the maximum value of current and axial magnetic field, is about 1ms in the center point of gap distance.

• Journal of the Korean institute of surface engineering
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• v.49 no.4
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• pp.363-367
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• 2016

For the industrial application of electropolishing process, we investigated electropolishing characteristics of stainless steel through increasing the specimen size or electrode gap. In this study, we performed a set of experiment with the specimen size of $10cm{\times}10cm$ and the electrode gap of 1 cm or more. In the view of the electropolishing process, the electrolyte temperature and the polishing time were most important factors compared with the current density and the electrode gap. Especially, the electrolyte temperature most importantly affected surface roughness and current efficiency on electropolishing characteristics. For the industrial application of electropolishing process, it should be considered for important factors such as electrolyte temperature, polishing time, current density and electrode gap, etc.

• Journal of Electrochemical Science and Technology
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• v.2 no.3
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• pp.152-156
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• 2011

A hybrid supercapacitor is fabricated using a composite material from $LiMn_2O_4$ (LMO) and activated carbon (AC) as the positive electrode and AC as the negative electrode to form the (LMO + AC)/AC system. Volume ratio (positive : negative) of electrodes is controlled to investigate of the power and energy balance. The (LMO + AC)/AC system shows better performances than the LMO/AC system. Especially, electrochemical impedance spectra, rate charge.discharge and cycle performance testing show that the (LMO + AC)/AC system have an outstanding electrochemical performance at volume ratios of (LMO + AC)/AC = 1 : 1.7 and 1 : 2. Electric double layer capacitor (EDLC) capacitance between AC of the positive electrode and AC of the negative electrode improves power density without loss of capacitance. Stable capacitance is achieved by lowering the positive electrode resistance and balancing the energy and power densities between the positive and negative electrodes by the addition of AC to the positive electrode at high current density.

• Journal of Electrochemical Science and Technology
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• v.12 no.1
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• pp.92-100
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• 2021

In this study, the use of waste food grade aluminium foil and mild steel as a sacrificial electrode in an electrocoagulation system was developed to remove reactive red 111 from wastewater. The effect of different parameters like pH, current density, electrode material, and different electrode configurations was investigated. Optimum operating conditions for maximum COD removal were determined as, 6 mA/㎠ current density and 30 min at 5 pH for aluminium foil and 7 pH for mild steel. Maximum COD reduction obtained at optimum conditions using monopolar 4 electrodes, monopolar 2 electrodes and bipolar electrode configuration were 96.5%, 89.3%, and 90.2% for Mild steel as a sacrificial electrode and 92.1%, 84.2%, and 88.6% for aluminium foil as a sacrificial electrode. The consumption of electrode and energy for both the electrodes of different configurations were calculated and compared. Using batch experimental data, a continuous-flow reactor was developed. Sludge analysis using Fourier Transform Infra-Red Spectroscopy (FTIR) analysis was done. Different adsorption kinetic models and isotherms were developed and it was found that pseudo second-order model and Langmuir isotherm fit best with the experimental data obtained.