• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.901-905
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• 2012

In this study, we investigated the pure geometrical effect of porous materials in gas adsorption using the grand canonical Monte Carlo simulations of primitive gas-pore models with various pore geometries such as planar, cylindrical, and random pore geometries. Although the model does not possess atomistic level details of porous materials, our simulation results provided many insightful information in the effect of pore geometry on the adsorption behavior of gas molecules. First, the surface curvature of porous materials plays a significant role in the amount of adsorbed gas molecules: the concave surface such as in cylindrical pores induces more attraction between gas molecules and pore, which results in the enhanced gas adsorption. On the contrary, the convex surface of random pores gives the opposite effect. Second, this geometrical effect shows a nonmonotonic dependence on the gas-pore interaction strength and length. Third, as the external gas pressure is increased, the change in the gas adsorption due to pore geometry is reduced. Finally, the pore geometry also affects the collision dynamics of gas molecules. Since our model is based on primitive description of fluid molecules, our conclusion can be applied to any fluidic systems including reactant-electrode systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.2
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• pp.237-242
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• 2012

In this paper, we investigated effects of ITO electrode geometry and dielectric layer thickness on the discharge Characteristic of AC PDP. As the dielectric thickness is decreased ($30{\sim}12{\mu}m$), firing and sustain voltage is decreased. Luminance and discharge power increase with decreasing dielectric layer thickness because of increasing capacitance between plasma and electrodes. Reactive power decreases with dielectric thickness due to reduced capacitance between sustain electrodes. For the high Xe test panel with small ITO electrode, luminous efficacy as well as luminance increase with decreasing dielectric layer thickness. This result suggest that high power density and small plasma volume is beneficial for high efficacy discharge.

• Journal of Industrial Technology
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• v.5
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• pp.81-89
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• 1985

A Mise-$\grave{a}$-la-masse method is to use a subsurface conductive mass itself as one current electrode of a pair by connecting it directly to one pole of a voltage source, the second current electrode being placed on the ground surface at a great distance and connected to the other pole. This paper is to study the modified Mise-$\grave{a}$-la-masse method using a water tank, that is, the second current electrode is placed on the underground level instead of being placed at a great distance, to find the geometry and the continuity of ore bodies.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1999.05a
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• pp.105-110
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• 1999

Wire electrical discharge machining (WEDM) is one of the unconventional machining processes, which is utilizing electrical energy to remove work-piece. In recent years WEDM used widely in die-sinking industry because WEDM can machine any hard materials if only it has conductivity and can machine accurately to the complex geometry, for fine wire is used in WEDM for the tool electrode. However WEDM is non-contact machining process, which is utilizing discharge phenomena occurring between two electrodes, the size of the machined part is larger than that of the tool electrode size. It is called discharge gap or clearance the difference size between the tool electrode and the machined part in WEDM. By the experiment clearances according to the machining condition was investigated.

• Journal of the Korean Ceramic Society
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• v.52 no.5
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• pp.356-360
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• 2015

The specific role of current collectors was investigated at the electrolyte/electrode interface of solid oxide fuel cells (SOFCs). Ag grids were fabricated as current collectors using electrohydrodynamic (EHD) jet printing for precise control of the grid geometry. The Ag grids reduced both the ohmic and polarization resistances as the pitch of the Ag grids decreased from $400{\mu}m$ to $100{\mu}m$. The effective electron distribution along the Ag grids improved the charge transport and transfer at the interface, extending the active reaction sites. Our results demonstrate the applicability of EHD jet printing to the fabrication of efficient current collectors for performance enhancement of SOFCs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.237-241
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• 1997

It is necessary to know the accurate field distribution around the high power apparatus, in designing it. To calculate the field around electrodes, we use the Charge Simulation Method(CSM) among several numerical methods and develop the new \"Field Analysis System\", by which we can draw the shape of electrodes, save the drawing in ascii code and apply CSM on the data. In the Field Analysis System, we try several rules for arrangement of simulation charge on CSM and consider their accuracy. At firs we simulate the case with simple electrode geometry and consider the adequacy of the rules. With tole field Analysis System applied the rules, we simulate the main electrode of load switchgear. As a result of the simulation, equipotential line, flux line and field strength on male electrode are drawn.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2109-2111
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• 2005

The effect of arc like streamer discharge is investigated on the hydrogen generation in the plasma reactor with multineedle - plate electrode geometry and SDR (Plasma reactor using the surface discharge). An additive of the two type (the saw type and the pellet type) was placed under the water surface to investigate the effect of the water surface conditions. The experimental results are compared in case of the reactor with and without an additive on the water surface. The generation of arc streamer discharge is more powerful with increasing applied voltage in the saw type. The maximum hydrogen Production concentration is about 4300 ppm at 74W in the SDR with additive of the saw type. Also, the Energy yield of the SDR (28990 g/kWh, 4300ppm, 74W) is higher than of the multineedle - plate electrode geometry (20892g/kWh, 3300ppm, 77W).

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.5
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• pp.7-12
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• 2008

This paper described results for desiging the best effective bushing geometry by comparing the distribution of the electric field according to bushing geometry. Twelve cases of the geometrical change are tried to analysis. Improvement of the insulation strength related with the vector and the electric field distribution are reached to about 0.7[%] and $21{\sim}26[%]$ by changing the electrode length, respectively. Moreover, in cases of the change of insulator thickness at high-voltage parts, the insulation strength relevant to the same parameters as mentioned above are 2[%] and $23{\sim}43[%]$, respectively Consequently, the quenching voltage for interrupting the partial discharge might be improved due to increasing the insulation strength by the geometrical change.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.1
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• pp.40-46
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• 2007

A laboratory scale experiment on phenol conversion properties by pulsed corona discharge process was carried out. Effects of operating parameters such as applied voltage, input oxygen, and electrode geometry on phenol conversion and solution properties were investigated. Electrical discharges generated in liquid phase increased the liquid temperature by heat transfer from current flow, decreased the pH value by producing various organic acids from phenol degradation, and increased conductivity by generating charge carriers and organic acids. The oxygen supply enhanced the phenol conversion through the ozone generation dissolution and the production of OH radicals. Series type electrode configuration induced more ozone production than reference type configuration because it produced gas phase discharges as well as liquid phase discharges. Therefore, the higher phenol conversion and TOC(total organic carbon) removal efficiency were obtained in series type configuration.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.74-80
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• 2003

Ionic wind is produced by a corona discharge when a DC high voltage is applied across the point-to-plane gap geometry. The corona discharge phenomena have been investigated in several beneficial application fields such as electrostatic cooling, ozone generation, electrostatic precipitation and electrostatic spraying. Recently ionic wind might be used in aerodynamic, for example, heat transfer, airflow modification, and etc. In this work, in order to analyze the control behavior of the velocity and amount of ionic wind produced by the positive DC corona discharges. The ionic wind velocity was measured as a function of the applied voltage, diameter of the punched hole on plate electrode and separation between the point-to-plate electrodes. As a results, the airflow is generated from the tip of needle to the plate electrode in the needle-to-punched-plate electrode systems. The ionic wind velocity is linearly increased with an increase in applied voltage and ranges from 1 to 3 m/sec at the locations of 100-200 mm from the punched-plate.