• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.88-94
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• 2012

In this study, the current-voltage curves for metals were measured using cyclic voltammetry. The relationship between the electrochemical properties and surface states of metals were investigated by Scanning Electron Microscope (SEM). In cyclic voltammetry, we used a 3-electrode system for the electrochemical measurements. The measurement was conducted at the condition that consists of the first reduction from the initial potential to -1350 mV, continuous oxidation to 1650 mV, and last reduction to the initial potential. The scan rates were 50, 100, 150 and 250 mV/s. The results show the C-V characteristics of metals to be for an irreversible process, which was caused by the oxidation current from cyclic voltammogram, when monoethanolamine (MEA) was used as a corrosion inhibitor. When we used MEA as a corrosion inhibitor, the diffusion coefficient was decreased as the concentration of electrolyte was increased. In the SEM images of copper, we observed an increase of surface corrosion at the increased electrolyte concentration. Addition of $1.0{\times}10^{-3}M$ corrosion inhibitor MEA reduced the effect of corrosion prevention due to the relatively large diffusion coefficient at the electrolyte concentration of 0.1N.

• Journal of the Korean Applied Science and Technology
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• v.30 no.1
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• pp.64-70
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• 2013

We investigated an electrochemical properties for Langmuir-Blodgett (LB) monolayer films of sphingomyelin and polyamic acid(1:1 molar ratio) mixture. LB monolayer films of mixture was deposited by the LB method on the indium tin oxide(ITO) glass. The electrochemical properties measured by cyclic voltammetry with three-electrode system in $KClO_4$ solution. The current of reduction and oxidation range was measured from 1650 mV to -1350 mV, continuously. The scan rates were 50, 100, 150, 200 and 250 mV/s, respectively. As a result, LB monolayer films of sphingomyelin and polyamic acid mixture was appeared on irreversible process caused by the reduction current from the cyclic voltammogram. Diffusion coefficient (D) in the sphingomyelin and polyamic acid mixture was calculated $2.67cm^2s^{-1}{\times}10^5$, $5.23cm^2s^{-1}{\times}10^6$ at 0.1 N and 0.2 N $KClO_4$ solutions, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7189-7195
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• 2015

The method of moments (MoM) is implemented to simulate scattering from a PEC (perfectly electric conductor) cylinder in the TE(transversw electric) EFIE (Electric Field Integral Equation) approach. The procedure expresses the singularity integral and the hypersingularity integral in terms of an analytic function and employs a singularity isolation process coupled with numerical technique along the discretized segment to evaluate the self terms. It is known that, in the MoM technique, the choice of base functions and test functions is very important for the accuracy and convergence of the numerical analysis. Thus, in this paper, three conditions, obtained from the combination of basis functions and test functions, are adopted to get the induced currents on the PEC surface. These currents are compared to the analytical one in the relative rms current error to get the condition that shows fast convergence rate. The fast order of convergence of the current error, 2.528, is obtained under the combination of pulse basis function/delta test function.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.66-73
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• 2014

In this work, the current-voltage curves for stainless steel in the ethanolamine solution containing alkyl group were measured using the conventional three electrodes of cyclic voltammetry. Stainless steel as working electrode, Ag/AgCl electrode as reference electrode and Pt wire as counter electrode were used respectively. As a result, the C-V characteristics of stainless steel were to be for an irreversible process due to the oxidation current from cyclic voltammogram, using N-ethylethanolamine and N,N-dimethylethanolamine solutions. Effective diffusivity of corrosion inhibitors was decreased with increasing concentration. It was found from SEM images of the metal that the electrolyte (specific name ?)(0.5 N) as corrosion inhibitor was added into a N, N-diethylethanolamine solution ($1.0{\times}10^{-3}M$) containing copper and nickel, the corrosion inhibiting effect was enhanced.

• JOURNAL OF ELECTRICAL WORLD
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• no.2 s.122
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• pp.95-101
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• 1987

• Journal of Korean Society of Environmental Engineers
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• v.32 no.4
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• pp.357-362
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• 2010

Electricity can be directly generated from organic matter even wastewaters using a microbial fuel cell. To achieve high power in MFCs, finding factors decreasing activation and Ohmic losses is very important. In this study we determined activation loss at the anode and cathode and Ohmic loss using the current interruption technique in a H-type MFC. Activation loss at the cathode was four times higher that that of anode activation loss even if pt-coated carbon (0.5 $mg/cm^2$;10%Pt) was used as the cathode. Ohmic loss determined using current interruption technique (1146 ${\Omega}$) was almost same as the internal resistance (1167 ${\Omega}$) measured using AC impedance. The sum of activation losses at the anode and cathode was the same as the value of activation loss of the cell.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.2
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• pp.71-77
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• 1996

The end-ring may contribute a significant influence to the performance of machine. The induced currents flow through the bars of a cage rotor and complete their closed paths by passing around the end-ring. This dissertation is to describe a method for calculating end-ring resistance of squirrel cage rotor, based on 3-D finite element method(A-$\Phi$). The resistance under consideration of skin effect is calculated by using Joule's loss equation.

• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.4
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• pp.30-38
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• 1974

This paper presents a method, which finds the current distribution and input impedance at the arbitrary feeding point of bended linear antenna in arbitrary shape in accordance with the MOMENT method. Practically the method of analysis is applied to the sinusoidal-shaped antenna, and the results of the calculation of current distribution and input impedance consist with the theoretical values. The method can be extensively used for the analysis of any of type antenna problems.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.216-217
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• 2013

본 논문에서는 전류적산법을 이용한 배터리 SOC 추정에 있어 오차를 발생시키는 원인들에 대한 이론적인 분석을 통하여 주요 인자들 중 전류센서, 스케일 변환회로, ADC에서 발생 가능한 오차 발생 요인을 고려한다. 그리고 오차를 반영한 시뮬레이션으로 BMS모델을 구현하여 실제 실험과의 정확성을 판단하고, 오차 발생 비중을 규명한다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.403.2-403.2
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• 2014

본 연구에서는 갭을 갖는 전극을 제작하고, 전극사이의 간격이 좁아짐에 따른 분석물질의 전기화학적 신호증폭현상을 확인하였다. 광 리소그래피와 전자빔 리소그래피를 이용하여 기본 전극을 구성하고 이를 바탕으로 전극의 표면에 금속의 환원을 유도함으로써 환원시간에 따라 전극이 점점 좁아지게 하는 방법을 이용하여 다양한 간격의 갭 전극을 제작하였다. 이와같은 방법으로 제작된 전극을 전기화학 신호분석장치에 연결하고, $2{\mu}m$의 간격부터 약 50 nm 까지의 다양한 전극 간격을 가지는 갭 전극 각각에 대한 전기화학적 신호를 분석하였다. 전극에 Ferricyanide 를 노출시켜 전극의 간격이 좁을수록 FeCN63-의 산화 환원에 따른 패러데이 전류가 증폭하는 것을 확인하였으며, 분석물질의 검출 한계 농도 또한 낮아짐을 확인하였다. 이러한 실험결과는 일정전위기의 순환전압전류법, 주사전자현미경, 원자힘현미경을 이용하여 분석되었다.