• 제목/요약/키워드: Impedance measurement

검색결과 872건 처리시간 0.024초

경락 임피던스 측정 시스템 개발에 관한 연구 (Study on the Development of Meridian Impedance Measurement System)

  • 이우철;인창식;민경기
    • 전기학회논문지
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    • 제58권2호
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    • pp.422-429
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    • 2009
  • Meridian which used as the basic theory of acupuncture treatment, is an important functional connection system of acupuncture point in oriental medicine. Yangdorak and EAV have lack of precision because of using 2-electrode method, occurring high non-uniformed current density and electrode contact status on electrode placement spot. Therefore we implemented a meridian impedance measurement system for measuring meridian impedance using 4-electrode method. In order to confirm the precision of developed system, we made an constant current characteristic experiment using standard resistor. As a results of clinical study with 18 subjects, the meridian impedance showed that reproductivity and repeatability of HT7 acupuncture point are $0.515[k{\Omega}]{\pm}0.000$(mean${\pm}$standard deviation) and $0.515[k{\Omega}]{\pm}0.002$, respectively. And reproductivity and repeatability of PC7 are $0.521[k{\Omega}]{\pm}0.000$ and $0.521[{\Omega}]{\pm}0.001$ respectively. The proposed system was stable and reliable. Therefore this study proved AC impedance method to valid in measuring meridian impedance, and also verified precision and repeatability of the proposed meridian impedance measurement system. The proposed system will serve as more effective method of measuring meridian phenomena as a bioelectric signal in clinical practice.

봉상접지전극의 접지임피던스의 주파수의존성의 분석 (Analysis of the Frequency Dependent Characteristics of Ground Impedance of a Ground Rod)

  • 이복희;엄주홍
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제53권8호
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    • pp.426-432
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    • 2004
  • This paper presents a systematic approach of measurement, modeling and analysis of grounding system impedance in the field of lightning protection system and intelligent power equipments. The measurement and analysis system of ground impedance is based on a computer aided technique. The magnitude and phase of ground impedance were determined by the novel measurement and analysis using the revised fall-of-potential method. The ground impedances of the ground rod of 50 m long are considerably dependent on the frequency. The ground impedance is mainly resistive in the frequency range of 3-20 kHz. At higher frequencies, the reactive components of the ground impedances are no longer negligible and the inductance of the ground rod was found to be the core factor deciding the ground impedance. Although the steady-state ground resistance of the ground rod of 50 m was less than that of the ground rod of 10 m, the ground impedances of the ground rod of 50 m over the frequency range of more than 60 kHz were much greater than those of the ground rod of 10 m. Furthermore, the equivalent circuit model based on the measured data was proposed. and the calculated results were in approximately agreement with the measured data.

Detection of Unbalanced Voltage Cells in Series-connected Lithium-ion Batteries Using Single-frequency Electrochemical Impedance Spectroscopy

  • Togasaki, Norihiro;Yokoshima, Tokihiko;Oguma, Yasumasa;Osaka, Tetsuya
    • Journal of Electrochemical Science and Technology
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    • 제12권4호
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    • pp.415-423
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    • 2021
  • For a battery module where single cells are connected in series, the single cells should each have a similar state of charge (SOC) to prevent them from being exposed to an overcharge or over-discharge during charge-discharge cycling. To detect the existence of unbalanced SOC cells in a battery module, we propose a simple measurement method using a single-frequency response of electrochemical impedance spectroscopy (EIS). For a commercially available graphite/nickel-cobalt-aluminum-oxide lithium-ion cell, the cell impedance increases significantly below SOC20%, while the impedance in the medium SOC region (SOC20%-SOC80%) remains low with only minor changes. This impedance behavior is mostly due to the elementary processes of cathode reactions in the cell. Among the impedance values (Z, Z', Z"), the imaginary component of Z" regarding cathode reactions changes heavily as a function of SOC, in particular, when the EIS measurement is performed around 0.1 Hz. Thanks to the significant difference in the time constant of cathode reactions between ≤SOC10% and ≥SOC20%, a single-frequency EIS measurement enlarges the difference in impedance between balanced and unbalanced cells in the module and facilitates an ~80% improvement in the detection signal compared to results with conventional EIS measurements.

유체의 흐름이 있는 엔진 흡기계용 직조관의 음향 임피던스 측정 및 전달손실 예측 (Measurement of acoustic impedance of porous woven hoses in engine intake systems in the presence of mean flow)

  • 이정권;박철민
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 춘계학술대회논문집
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    • pp.996-1000
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    • 2002
  • A porous tube, comprised of a resin-coated woven fabric has recently been used as an effective component for use in intake systems of internal combustion engines to reduce the intake roaring. For the prediction of the acoustic performance of an engine intake system with a porous woven hose, the acoustic wall impedance of the hose must be known. Because of its peculiar acoustical and structural characteristics, the accurate measurement of the wall impedance ofa porous woven hose is not easy. A new measurement technique is proposed herein, that is valid over the low to mid frequency ranges. The acoustics impedance is inversely estimated from an overdetermined set of measured pressure transmission coefficients for specimens of different lengths and the reflection coefficient of end termination. The method involves only one measurement, and, as a result, it is very simple. The measured TL for samples with arbitrary conditions, arbitrary porous frequency, arbitrary length, and arbitrary mean flow condition, are in reasonably good agreement with values predicted from curve-fitted impedance data.

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봉상전극 접지임피던스의 측정과 이론적 분석 (Theoretical analysis and measurement of Ground impedance of Ground rods)

  • 이복희;이태형;이수봉;엄주홍
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2004년도 하계학술대회 논문집 C
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    • pp.1876-1878
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    • 2004
  • A systematic approach of measurement, modeling and analysis of grounding system impedance is presented. The measurement and analysis system of ground impedance is based on a computer aided technique. The ground impedances of the ground rod are considerably dependent on the frequency. The ground impedance is mainly resistive in the frequency range of 3-20 kHz. At higher frequencies, the reactive components of the ground impedances are no longer negligible and the inductance of the ground rod was found to be the core factor deciding the ground impedance. As a consequence, the equivalent circuit model based on the measured data was proposed, and the calculated results were in approximately agreement with the measured data.

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임피던스 측정을 이용한 세포의 변형성 분석용 미소유체 칩 (Microfluidic chip for characterization of mechanical property of cell by using impedance measurement)

  • 김동일;최은표;최성식;박정열;이상호;윤광석
    • 센서학회지
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    • 제18권1호
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    • pp.42-47
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    • 2009
  • In this paper we propose a microfluidic chip that measures the mechanical stiffness of cell membrane using impedance measurement. The microfluidic chip is composed of PDMS channel and a glass substrate with electrode. The proposed device uses patch-clamp technique to capture and deform a target cell and measures impedance of deformed cells. We demonstrated that the impedance increased after the membrane stretched and blocked the channel.

접지임피던스의 주파수 의존성 측정기법 (Measurement Method of the Frequency Dependent Characteristics of Ground Impedance)

  • 엄주홍;이복희
    • 한국정보통신설비학회:학술대회논문집
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    • 한국정보통신설비학회 2004년도 하계학술대회
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    • pp.211-214
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    • 2004
  • The measurement system of ground impedance is based on a computer aided technique. The magnitude and phase of ground impedance were determined by the novel measurement and analysis using the revised fall-of-potential method. The ground impedances of the ground rod of 30 m long are considerably dependent on the frequency. The ground impedance is mainly resistive in the frequency range of 3-20 kHz. At higher frequencies, the reactive components of the ground impedances are no longer negligible and the inductance of the ground rod was found to be the core factor deciding the ground impedance.

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차음시트의 음향투과손실 측정에 관한 연구 (A Study on the Sound Transmission Loss Measurement of Sound Isolation Sheets)

  • 이동훈;강문;이주원;정갑철;권영필
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 추계학술대회논문집
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    • pp.409-414
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    • 2000
  • A new impedance tube method is presented for the measurement of transmission loss of sound isolation sheets. The two-microphone method based on the sound decomposition theory proposed by Seybert and Ross is reviewed in this impedance tube method, which has been used for the determination of absorption coefficient of absorptive materials as well as transmission loss of automotive mufflers. Sound transmission losses for rubber, polyvinyl and asphalt sheets are measured in an impedance tube and reverberation room facility, respectively. By comparing two measurement methods, the reliability of impedance tube method used in this study is validated. From the experimental results, it is shown that the accuracy of sound isolation capability obtained by the impedance tube method depends upon the microphone spacing and the distance of the first microphone from the test sample surface.

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RF 정합 특성 개선을 위한 챔버의 임피던스 측정법 (Measurement Technology of Chamber Impedance for RF Matching)

  • 설용태;이의용;박성진
    • 반도체디스플레이기술학회지
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    • 제2권4호
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    • pp.13-17
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    • 2003
  • An adaptor is designed for chamber impedance measurement of plasma process. Copper rod, fixed board and compensation circuit are the major components of the adaptor. An adaptor can be to measure chamber impedance on time unless stopping a process and Data to measure can do the database. We can use it to a criteria data for a failure diagnosis. So developed adaptor could be used for diagnosis the plasma process chamber in semiconductor industry.

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경락노선상 임피던스 측정기(MIR-2)의 측정신뢰도 개선방안 연구 (Improvement of the repeatability and reproducibility of the meridian impedance measurement system MIR-2)

  • 인창식;이혜정;김종열;이우철
    • Korean Journal of Acupuncture
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    • 제24권4호
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    • pp.55-67
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    • 2007
  • Objectives : The repeatability and reproducibility of MIR-2, a newly developed impedance measurement device (four electrode method) on skin are of the meridian system, is evaluated and a method to improve the reliability is discussed. Methods : Multiple gage R&R studies were conducted for the impedance measurements over bilateral KI3 acupoint in ten participants by three assessors using MIR-2 device. Gage R&R studies were repeated after controlling the acupoint locating method or one value correction by replacing one assessor's outlying value with an average of the other assessors' values to explore any feasibility of improvement of measurement reliability. Results : Controlling acupoint locating method and replacing one value with an average of other assessors' value led to improved variation metrics in a gage R&R study. Conclusions : Measurement reliability can be improved by controlling measurement procedures or by using repeated measurement method, which will facilitate development of clinically applicable measurement device with reliability.

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