• 전자공학회논문지
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• 제50권10호
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• pp.245-251
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• 2013

정보통신설비용 접지전극의 임피던스는 접지전극이 매설되어 있는 토양의 전기적 특성과 밀접한 관계가 있다. 특히 인가된 전계의 주파수에 따른 토양의 유전율과 도전율 특성이 접지전극의 임피던스에 직접적으로 영향을 준다. 접지전극의 임피던스를 계산할 수 있는 상용프로그램은 유전율과 도전율을 수정하여 시뮬레이션하는 것이 불가능하기 때문에 전자계 이론을 적용한 프로그램을 MATLAB으로 구현하였다. 토양의 유전율은 유전완화 모델인 디바이(Debye)식을 적용하였으며, 도전율은 실험에서 얻어진 수식을 다른 논문에서 인용하였다. 시뮬레이션 결과의 신뢰성을 확인하기 위해서 실험계를 구성하여 접지전극의 임피던스를 측정하고, 시뮬레이션 결과와 서로 비교하였다. 그 결과, 토양의 유전율과 도전율 특성을 고려한 본 논문 결과가 고려하지 않은 상용프로그램(NEC) 결과 보다 측정값과 더욱 잘 일치하는 것을 확인하였다.

• 한국전기전자재료학회논문지
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• 제13권12호
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• pp.1051-1057
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• 2000

A traveling-wave CPW(coplanar waveguide) electrode with abruptly broken input/output-taper for LiNbO$_3$optical modulator was designed and fabricated. The electrical characteristics of traveling-wave electrode on z-cut LiNbO$_3$crystal with SiO$_2$buffer layers were measured by network analyzer. To confirm the possibility of the electro-optic modulator electrode, detailed calculations of the impedance, microwave effective index and attenuation constants are presented as a function of the microwave electrode thickness, but the buffer layer thickness is fixed as 1${\mu}{\textrm}{m}$. These characteristics are discussed from the viewpoint of the device optimization and are expected to be design guides for the LiNbO$_3$modulator’s electrodes.

• 조명전기설비학회논문지
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• 제19권6호
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• pp.46-51
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• 2005

접지 시스템은 전기설비의 기준 전위점을 확보할 뿐만 아니라 대지에 낮은 저항으로 고장 전류를 흐르게 한다. 주파수에 대한 함수로 접지임피던스는 고장전류가 넓은 범위의 주파수를 포함하기 때문에 접지 성능을 평가하는데 필요하다. 동봉은 배전계통에서 가장 많이 쓰이는 접지 전극이다. 본 논문에서는 동봉의 접지임피던스를 주파수 60[Hz]에서 100[kHz] 범위까지 측정하였고, 접지임피던스를 회로 모델과 전달함수 모델로 구하여 측정된 값과 비교 검토하였다.

• 한국표면공학회지
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• 제49권6호
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• pp.498-506
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• 2016

Electrochemical measurement using a LSCF6428 electrode was performed to estimate the oxygen potential gradient in the electrode layer and a long time stability test was performed by applied potential to learn the overpotential effect on the LSCF6428 electrode. By fitting the observed impedance spectra, it was obtained that the amount of faradic current decreased with distance from cathode/electrolyte interface. Oxygen potential gradient was estimated to occur within 1 um region from the cathode/electrolyte interface at an oxygen partial pressure of 10-1 bar. The segregation of cation rich phases in the LSCF6428 electrode suggests that kinetic decomposition took place. However, impedance response after applying the potential showed no changes in the electrode compared with before applying potential. The obtained results suggest that segregation of a secondary phase in a LSCF6428 cathode is not related to performance degradation for solid oxide fuel cells (SOFCs).

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.211-215
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• 2008

This paper deals with the transient ground impedance of small-sized needle-rod installed in a test field, Impulse voltage generator was used to inject lightning impulse on a ground electrode and modified fall-of potential method was proposed to measure the high ground potential rise. Transient ground impedance was analysed with impedance curve and I-V curve as respects the resistivity of soil. Soil ionization near the ground electrode is activated in high resistivity soil and have an effect on the reduction of transient ground impedance significantly.

• Journal of Ceramic Processing Research
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• 제13권spc2호
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• pp.163-165
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• 2012

Impedance spectroscopy informs electrical properties of materials as accumulated charges, contact status between electrode and organic materials. We carried out impedance spectroscopy of organic light-emitting diodes as ITO/Alq3(60 nm)/Al on temperatures from 10 K to 300 K. The result described Z'-Z" plot, cole-cole plot and dielectric relaxation time τ. Z'-Z" plot means that real and imaginary part of materials in organic and electrode by frequencies and temperature. Z' as real part of impedance by applied frequency depending on temperature shows the plateau in low frequency region as Rs+ Rp and over 100 kHz in high frequency region as Rs. Cole-cole plot shows resistance of materials in equivalent circuit of the device by temperatures. And equivalent circuit and dielectric relaxation could be accomplished by using the complex impedance analysis.

• 센서학회지
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• 제26권2호
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• pp.73-78
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• 2017

A tetrode is one of the neural electrodes, and it is widely used to record neural signals in the brain of a freely moving animal. The impedance of a neural electrode is an important parameter because it determines the signal-to-noise ratio of the recorded neural signals. Here, we developed a modification technique using carbon nanotube-polypyrrole composite nanostructures to decrease the impedances of tetrodes. The synthesis of the carbon nanotube and polypyrrole nanostructures was performed in two steps. In the first step, randomly dispersed carbon nanotubes and pyrrole monomers were gathered and aligned on the tetrode electrode. Next, they were electro-polymerized on the electrode surface. As the applied time (step-1 and step-2) and the offset voltage increased, the impedances of the tetrodes decreased. The modification technique is, therefore, an important and useful of lowering the impedances of tetrodes.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권9호
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• pp.383-387
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• 2003

In this paper, we have studied about optimal transmission efficiency characteristics of pulse energy in a coal plant for removing environmental polluted gas. The electrical efficiency of pulse power systems depends on impedance of the reactor. To obtain high efficiency, we used MPC(Magnetic pulse compressor) as the power switch and tested their characteristics as electrode length of the reactor and charging voltage of capacitor, As results, we obtained a compressed pulse such as pulse voltage of 10㎸, rising time 200ns and pulse width of 500ns. With increasing electrode length, the load impedance was decreased but the electrical efficiency was increased.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(5)
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• pp.218-221
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• 2000

The electronystagmography(ENG) means to measure and record CRP(Corneal-Retinal Potential) whenever the eyeball is moved by using a skin electrode stuck to the hi-temporal and the difference of CRP. Both the horizontal and vertical movement are known according to the position of the stuck skin electrode. In this paper, the variable time-constances to record the eyeball signal of the conventional EOG(Electro-Oculograph) Amplifier is chosen. The shorter the time-constance is, the worse the distortion of a signal is. But the unbalanced impedance of the electrode stuck on the hi-temporal is reduced. Also, the longer the time-constance is, the less the distortion of it signal is. But it is sensitive to the change of base line according to the unbalanced impedance. In order to solve these problems, an DC-Amplifier, the distortion of the eyeball signal is globally used. By solving unbalanced impedance problem of EOG amplifier, the distortion ratio of EOG amplifier is improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1850-1852
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• 2002

In this paper, we studies EMTP analysis and characteristics of critical voltage of pulse corona and load impedance on variable electrode length. To obtain a stable Pulse voltage, we designed a compact pulse generator switched MOSFET and tested their characteristics by adjusting electrode length and pulse repetition. As a result, critical voltage of pulse corona and load impedance on increasing electrode length were decreased. These results indicate we can control critical voltage of pulse corona and suppress arc discharging between two electrodes.