• Electrical & Electronic Materials
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• v.7 no.6
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• pp.543-548
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• 1994

전기화학반응은 일반적으로 반응속도가 전류에, 반응의 구동력이 과전압에 대응하기 때문에 전류 또는 전위의 경시적 변화로 부터 적극 반응기구나 반응의 과정을 해석하는 법이 널리 이용되고 있다. cyclic voltammetry과 chrono-potentiometry을 비롯한 시간영역에서의 해석에 대해, 전극계의 동적인 특성을 주파수 영역에서 해석하는 것도 가능하며 교류임피던스법이 가장 잘 알려진 방법이다. 여기서는 교류임피던스법의 고찰법, 기본적인 측정법, 몇개의 계에 있어서 임피던스 특성 및 그 방법의 새로운 전개에 대해서 설명한다.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.211-214
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• 1999

염화물 및 방청제가 함유된 철근 콘크리트의 부식특성을 마크로 셀 부식측정 방법인 갈바닉 전류 측정과 마이크로 셀 부식측정 방법인 선형분극 측정법 및 교류 임피던스법을 이용하여 염화물 및 방청제의 영향을 평가하였다. 마크로/마이크로 셀 부식측정기 Calcium Nitrite 방청제가 첨가된 시험체의 경우 갈바닉 전류 측정결과 낮은 전류값을 유지하였고, 교류 임피던스 측정결과 분극저항의 감소가 나타나지 않았으므로, 방청제의 첨가가 콘크리트내 철근의 부동태 피막을 보호하여 부식저항성을 향상시킴을 알 수 있었다.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.207-209
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• 2004

저압간선의 굵기산정시 일반적으로 간이 계산식이 사용되고 있으나 이는 교류 임피던스를 적용한 정식과는 허용 전압강하를 기준으로한 포설거리에서 차이가 있으므로 저압간선의 설계시 보다 정확한 계산을 위해 교류 임피던스를 기준으로한 정식을 사용하여 계산이 이루어져야 한다. 따라서, 본 논문에서는 정식과 간이식에 따른 계산결과와 실측을 통한 전압강하를 비교하여 정확한 전압강하 계산법을 검토하여 보았다.

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.211-218
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• 2000

The effects of alloying elements, Cr, Mo, and N on repassivation characteristics of stainless steels were investigated by using the abrading electrode technique and a.c impedance spectroscopy. The role of alloying elements on the stability of passive film and their repassivation characteristics were examined using alloy steels such as Fe-Cr, Fe-Cr-Mo, 304, 304LN, 316, and 316LN. The electrochemical characteristics of the passive film were investigated by in-situ d.c. and a.c. electrochemical methods. Localized corrosion resistance is believed to have much to do with the stability and repassivation characteristics of the passive film. The effects of alloying elements on the current transients and repassivation kinetics were systematically examined by using the abrading electrode technique and a.c. impedance spectroscopy. The experimental results were analyzed in order to elucidate the relationship between passive film stability, repassivation characteristics, and alloying elements.

• 한국전기화학회:학술대회논문집
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• 1999.04a
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• pp.44-44
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• 1999

• Journal of the Korean Electrochemical Society
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• v.3 no.4
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• pp.191-195
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• 2000

Electrochemical properties of the oxygen electrode in phosphoric acid fuel cell have been studied using AC impedance method as a function of applied potential, operating temperature and teflon content in the electrode. The oxygen electrode reaction in the $105wt.\%$ phosphoric acid is characterized by a parallel resistive component, $R_p$ and a capacitive component, $C_p$ with serial electrolyte resistance, $R_s$. The conductivity of the phosphoric acid is found to be 0.31-0.47 S/cm in the range of $130\;to\;190^{\circ}C$ from the measured impedance. The increase of applied potential and temperature produced the decreased RP and the increased $C_p$, which means the increase of the oxygen electrode reaction rate. The single cells with the cathode of various teflon contents were tested, and the cathode with $40wt.\%$ teflon showed good performance, which is considered to be related to an optimized impedance behavior.

• Proceedings of the Materials Research Society of Korea Conference
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• 1997.05a
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• pp.88-88
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• 1997

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.693-696
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• 2006

In this study, we made the system to measure variation of blood flow using bio-electrical impedance analysis method. The system, which could measure variation of impedance according to pressure change by artificial pressure, consists of pressure measurement and impedance measurement by 4-electrode method. Pressure measurement splits into semiconducting pressure sensor and electronic circuit for processing output signal. In addition, impedance measurement splits into constant current source circuit and lock-in amplifier for detection impedance signal. We experimented feature of impedance measurement using standard resistance to evaluate the system characteristic. As well as, we experimented to estimate variation of blood flow by measuring impedance and blood flow resistance ratio using mean arterial pressure and variation of blood flow with experimental group. As result of this study, blood flow resistance ratio and variation of blood flow were definitely in inverse proportion and were -0.96776 as correlation coefficient by correlation analysis.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.8
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• pp.86-92
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• 2009

In order to minimize ac mutual coupling, the auxiliary electrode are located at a right angle in measuring ground impedance. In case that the measurement space is limited, the alternative method is employed. At that time, it is necessary to investigate the measurement errors due to ac mutual coupling and earth mutual resistance in measuring the ground impedances. 'This paper presents the measurement accuracy according to the location of the current and potential auxiliary electrodes in measuring ground impedance of vertically or horizontally buried ground electrode. The measurement errors due to ac mutual coupling were evaluated Consequently, the effect of ac mutual coupling on the measurement accuracy for horizontally buried ground electrode is greater than that for vertically buried ground electrode. Measurement errors due to ac mutual coupling is the largest when the current and potential auxiliary electrodes are located in parallel. The 61.8[%] rule is inappropriate in measuring ground measurement. Theoretically, in case that the angle between the current and potential auxiliary electrodes is 90$[^{\circ}]$, there is no ac mutual coupling. If it is not possible to route the current and potential auxiliary electrodes at a right angle with limitation of measurement space, the location of these electrodes with an obtuse angle is preferred to that with an acute angle in reducing the measurement errors due to ac mutual coupling.

• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.1 s.24
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• pp.9-14
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• 2006

Analysis has been made of the anti-corrosive property of organic coating under the shear stress of the flow by means of AC impedance method. Marine anti-corrosive painted panels were placed in the water channel with varying flow rate, thereby experiencing varying flow shear stress on the surfaces. The velocities of the salt water were ranged from 1.48 to 5.2 m/s and the coating thickness of from $70{\mu}m\;to\;140{\mu}m$. For all coating thicknesses investigated, the poorer anti-corrosive property and the lower adhesion strength have been found for the higher shear stress. It has been found that the shear stress accelerates the aging of organic marine coatings.