• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.6
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• pp.1087-1091
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• 2007

Exact impedance modeling of the electrode/electrolyte interface is important in bio-signal sensing electrode development. Therefore, the investigation of the equivalent circuit models for the interface has been pursued for a long time by several researchers. Previous circuit models fit the experimental results in limited conditions such as frequency range, type of electrode, or electrolyte. This paper describes a new electrical circuit model and its capability of fitting the experimental results. The proposed model consists of three resistors and two constant phase elements. Electrochemical impedance spectroscopy was used to characterize the interface for Au, Pt, and stainless steel electrode in 0.9% NaCl solution. Both the proposed model and the previous model were applied to fit the measured impedance results for comparison. The proposed model fits the experimental data more accurately than other models especially at the low frequency range, and it enables us to predict the impedance at very low frequency range, including DC, using the proposed model.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.327-329
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• 2002

This paper is based on model electrode by reduced scale and theoretical background of proportion factor. use building structure and mesh electrode, we get grounding electrode of building grounding structure and grounding electrode of mesh electrode by modeling experimentation and estimation coordinate geometry, we are doing practical grounding electrode assumption.

• Progress in Superconductivity and Cryogenics
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• v.6 no.1
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• pp.48-52
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• 2004

Breakdown characteristics of insulator-liquid nitrogen ($LN_2$) composite insulation for resistor type High $T_c$/ superconducting fault current limiter (HTSFCL) under ac and impulse voltage in $LN_2$ has been studied using model electrode systems. Electrodes for model electrode systems were made of SUS 304 contacted fiberglass reinforced plastic (FRP) and Au coated sapphire. The breakdown characteristics of model electrode systems were investigated experimentally for FRP thickness ranging from 1 mm to 5 mm. surface distance ranging from 2.5 mm to 7 mm and electrode gap ranging from 1 to 5 mm. The experimental data suggested that the breakdown voltage of model electrode systems in $LN_2$ is highly dependent on the surface distance, electrode gap as well as on the FRP thickness. Also, we had observed discharge traces and puncture due to high-voltage 60-Hz AC stress.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.490-490
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• 2013

In semiconductor industry, it is expected that plasma process which use 450 mm source will be used at next generation. However, main obstacle of the large area plasma source is plasma uniformity from it. When electrode is enlarged, field difference between center area and side area reduces the plasma uniformity [1-3]. Therefore we investigate multi-electrode which diminish this field difference.We designed two multi-electrode models. One has two segments and the other has five segments. Each multi-electrode model is connected with two power generator and two matchers. One generator and one matcher is connected with center electrode part. The other one generator and the other one matcher is connected with side electrode part. The ion density is measured at 29 points by using floating harmonic method [4-6]. After measuring the data of each multi-electrode model, we discuss the difference of profile between two models' data.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.8
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• pp.35-42
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• 2020

In discharge machining, material is removed by electrical discharge between the electrode and the workpiece. An important consideration in EDM is that the wear of the electrodes decreases the final precision of the workpiece. The edge wear of the electrodes proceeds very quickly because sparks occur more frequently at the edges with high local electrical strength. In this study, mold steel was discharged with a wedge-shaped graphite electrode to measure the edge wear of the electrode according to the depth. The electrode edge wear increased with depth during EDM and a wear model was developed. The model predicted that the edge wear can be reduced by approximately 70% using two electrodes instead of a single electrode. The model was supported by the experimental comparison of the dual electrode method and the single electrode method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.268-274
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• 2013

Electric discharge machining drill (EDM-drill) is an efficient process for the fabrication of micro-diameter deep metal hole. As there is non-physical contact between tool (electrode) and workpiece, EDM-drill is widely used to machine the hard machining materials such as high strength steel, cemented carbide, titanium alloys. The electro-thermal energy forces the electrode to wear out together with the workpiece to be machined. The electrode wear occurs inside of a machining hole. and It causes hard to monitor the machining state, which leads the productivity and the quality to decrease. Thus, this study presents a methodology to estimated the electrode wear amount while two coefficients (scale factor and shape factor) of the logarithmic regression model are evaluated from the experiment result. To increase the accuracy of estimation model, the linear transformation method is adopted using the differences of initial electrode wear differences. The estimation model is verified through experiment. The experimental result shows that within minute error, the estimation model is able to predict accurately.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.330-332
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• 2002

There are a lot errors and little accuracy when calculating the grounding resistance with the transposition methods in the equivalent surface of hemisphere electrode. Therefore we should calculate the grounding resistance by using the mesh factor. In this paper, we would estimated the grounding value of mesh electrode with water tank model & estimation method using the reduced scale ratio of mesh electrode based on the theory of model electrode & proportional factor according to the reduced scale ratio. And also we have confirmed the accuracy of the empirical formula of model electrode by using by regression analysis.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.29-33
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• 2002

There are a lot of errors and little accuracy when calculating the grounding resistance with the transposition methods in the equivalent surface of hemisphere electrode. Therefore we should calculate the grounding resistance by using the mesh factor, In this paper, we would estimate the grounding value of mesh electrode with water tank model & estimation method using the reduced scale ratio of mesh electrode based on the theory of model electrode & proportional factor according to the reduced scale ratio. And also we have confirmed the accuracy of the empirical formula of model electrode by using the regression analysis.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.274-275
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• 2007

The investigation of the equivalent circuit models for the electrode/electrolyte interface has been pursued for a long time by several researchers. Previous circuit models fit the experimental results in limited conditions such as frequency range, type of electrode, or electrolyte. This paper describes a new electrical circuit model and its capability of fitting the experimental results. Electrochemical impedance spectroscopy was used to characterize the interface for Au, Pt, and stainless steel electrode in 0.9% NaCl solution. Both the proposed model and the previous model were applied to fit the measured impedance results for comparison. The proposed model fits the experimental data more accurately than other models especially at the low frequency range, and it enables us to predict the impedance at very low frequency range, including DC, using the proposed model.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.243.1-243.1
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• 2014

For two-dimensional grid electrodes immersed in plasmas, sheath expansion due to negative high-voltage pulse applied to the electrode generates high-energy pseudowave. The high-energy pseudowave can be used as ion beam for ion implantation. To estimate ion dose due to high-energy pseudowave, investigation on sheath expansion of grid electroes is necessary. To investigate sheath expansion, an analytic model was developed by Vlasov equation and applying the 1-D sheath expansion model to 2-D. Because of lack of generalized 2-D Child-Langmuir current, model cannot give solvable equation. Instead, for a given grid electrode geometry, the model found the relations between ion distribution functions, Child-Langmuir currents, and sheath expansions. With these relations and particle-in-cell (PIC) simulations, for given grid electrode geometry, computation time was greatly reduced for various conditions such as electrode voltages, plasma densities, and ion species. The model was examined by PIC simulations and experiments, and they well agreed.