• Title/Summary/Keyword: Electrode

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A New Measurement Method of Dielectric Constants Applied the Principles of Cross Capacitance (Cross Capacitance 원리를 작용한 새로운 유전상수 측정방법 제안)

  • Kim, Han-Jun;Lee, Rae-Duk;Kang, Jeon-Hong;Yu, Kwang-Min;Han, Sang-Ok
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.1084-1087
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    • 2002
  • The guard-ring type 3-terminal parallel plate electrodes proposed by ASTM D 150-81 and IEC 250 have been widely used for measurement of dielectric constants of solid dielectrics. However the method using this electrodes causes many uncertainty associated with the measurement errors of the diameter of the guarded electrode. the gap between guarded and guard-ring electrode. the distance of two active electrodes(the thickness of specimen), the roughness and contamination of surface of electrode and specimen. close adherence grade of electrode and specimen. In this paper. a new electrode system of cross capacitance type based on Thompson-Lampard theorem is designed and is employed for the measurement of dielectric constant. The results of simulation of guard-ring electrode and cross capacitance electrode using FEM program show that distance measurement between two electrodes in guard-ring electrode produces large uncertainty. on the other hand this effect in cross capacitance electrode is negligible. Furthermore. the air gap effects in the cross capacitance electrode is 5.6 times less sensitive than that in guard-ring electrode by assuming air gap of $50{\mu}m$.

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A Study on Signal Feature Extraction of Partial Discharge Types Using Discrete Wavelet Transform Technique (이산웨이블렛 변환기법을 이용한 부분방전종류의 신호특징추출에 관한연구)

  • Park, Jae-Jun;Jeon, Byung-Hoon;Kim, Jin-Seong;Jeon, Hyun-Gu;Baek, Kwan-Hyun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.170-176
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    • 2002
  • In this papers, we proposed the feature extraction method due to partial discharge type of transformers. For wavelet transform, Daubechie's filter is used, we can obtain wavelet coefficients which is used to extract feature of statistical parameters (maximum value, average value, dispersion, skewness, kurtosis) about acoustic emission signal generated from each partial discharge type. The defects which could occur in a transformer were simulated by using needle-plane electrode, IEC electrode and Void electrode. Also, these coefficients are used to identify signal of partial discharge type electrode fault in transformer. As a result, from compare of acoustic emission amplitude and acoustic average value, we are obtained results of IEC electrode> Void electrode> Needle-Plane electrode. otherwise, In case of skewness and kurtosis, we are obtained results of Needle-Plane electrode electrode> Void electrode> IEC electrode.

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A Comparison of Spot Weldability with Electrode Force Changes in Surface Roughness Textured Steel (가압력 변화에 따른 표면조도처리 강판의 저항 점 용접성 비교)

  • Park, Sang-Soon;Park, Yeong-Do;Kim, Ki-Hong;Choi, Yung-Min;Rhym, Young-Mok;Kang, Nam-Hyun
    • Journal of Welding and Joining
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    • v.26 no.2
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    • pp.75-84
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    • 2008
  • With the development of surface roughness textured steel for automotive body-in-white assemble, one of key issues is to understand the role of the surface roughness in textured steel sheets. To investigate effect of surface roughness on weldability in prepared steels, electrode force was varied. Steel sheets (T-H) with high surface roughness ($Ra\;=\;1.94\;{\mu}m$) reduced electrode life. It was attributed to the higher contact resistance at the electrode-sheet interface in the presence of the high surface roughness. The increased electrode diameter decreased current density, therefore reducing weld electrode life due to small weld button size. When an increased electrode force was used, a significant increase in the electrode life was observed in welding of high surface roughness steel sheet. This study suggested that contact resistance at the electrode-sheet interface was the dominant factor, as compared to the sheet-sheet interface for determining electrode life in welding of surface roughness textured steel.

The Characteristics of a Superposed Discharge Type Ozonizer with Variation of Mesh in Internal Electrode (내부전극 조밀도 변화에 따른 중첩방전형 오존발생기의 특성)

  • Song, Hyun-Jig
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.5
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    • pp.87-93
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    • 2005
  • In order to develope high concentration$\cdot$yield ozonizer, superposed discharge type ozonizer using overlap of silent discharge and internal electrode of mesh type has been designed and manufactured. It consists of three electrodes(central electrode, internal electrode and external electrode) and double gaps(gap between central electrode and internal electrode, gap between internal electrode and external electrode). Therefore, ozone is generated by overlapping silent discharges generated between the gaps respectively for which the AC high voltages applied to the internal electrode and the external electrode has a $180{[^\circ]}$ phase difference and for which the central electrode is a ground Ozone generation characteristics proportional to mesh of internal electrode by increasing of discharge electrode and controlling of discharge power density. As a result, the in maximum ozone concentration, generation, and yield can be obtained 17,720[ppm], 5.4[g/h], and 205[g/kwh] respectively.

Mechanically Immobilized Copper Hexacyanoferrate Modified Electrode for Electrocatalysis Amperometric Determination of Glutathione

  • D. Davi Shankaran;S. Sriman Narayanan
    • Bulletin of the Korean Chemical Society
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    • v.22 no.8
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    • pp.816-820
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    • 2001
  • A new copper hexacyanoferrate modified electrode was constructed by mechanical immobilization. The modified electrode was characterised by cyclic voltammetric experiments. Electrocatalytic oxidation of glutathione was effective at the modified electrode at a significantly reduced overpotential and at broader pH range. The modified electrode shows a stable and linear response in the concentration range of 9 ${\times}$10-5 to 9.9 ${\times}$10-4M with a correlation coefficient of 0.9995. The modified electrode exhibits excellent stability, reproducibility and rapid response and can be used in flow injection analysis for the determination of glutathione.

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Assumption of Grounding Electrode by Model Experiment (모델실험에 의한 접지전극의 상정)

  • Koh, Hee-Seog;Kim, Maeng-Hyun;Park, Seung-Jae;Song, Won-Pyo;Kim, Ju-Chan
    • Proceedings of the KIEE Conference
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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.

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Interaction Between Transparent Dielectric and Bus Electrode for Heating Profile in PDP

  • Lee, Sang-Wook;Kim, Dong-Sun;Park, Mi-Kyung;Hwang, Seong-Jin;Kim, Hyung-Sun
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.864-866
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    • 2007
  • In PDP, bus electrode should have low resistance for high efficiency. The transparent dielectric affects the shape change of bus electrode during the firing. These are related with the electrical property of the electrode. In this study, the shape of electrode was controlled by firing schedules of the transparent dielectric and the bus electrode.

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Development of an Active Dry EEG Electrode Using an Impedance-Converting Circuit (임피던스 변환 회로를 이용한 건식능동뇌파전극 개발)

  • Ko, Deok-Won;Lee, Gwan-Taek;Kim, Sung-Min;Lee, Chany;Jung, Young-Jin;Im, Chang-Hwan;Jung, Ki-Young
    • Annals of Clinical Neurophysiology
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    • v.13 no.2
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    • pp.80-86
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    • 2011
  • Background: A dry-type electrode is an alternative to the conventional wet-type electrode, because it can be applied without any skin preparation, such as a conductive electrolyte. However, because a dry-type electrode without electrolyte has high electrode-to-skin impedance, an impedance-converting amplifier is typically used to minimize the distortion of the bioelectric signal. In this study, we developed an active dry electroencephalography (EEG) electrode using an impedance converter, and compared its performance with a conventional Ag/AgCl EEG electrode. Methods: We developed an active dry electrode with an impedance converter using a chopper-stabilized operational amplifier. Two electrodes, a conventional Ag/AgCl electrode and our active electrode, were used to acquire EEG signals simultaneously, and the performance was tested in terms of (1) the electrode impedance, (2) raw data quality, and (3) the robustness of any artifacts. Results: The contact impedance of the developed electrode was lower than that of the Ag/AgCl electrode ($0.3{\pm}0.1$ vs. $2.7{\pm}0.7\;k{\Omega}$, respectively). The EEG signal and power spectrum were similar for both electrodes. Additionally, our electrode had a lower 60-Hz component than the Ag/AgCl electrode (16.64 vs. 24.33 dB, respectively). The change in potential of the developed electrode with a physical stimulus was lower than for the Ag/AgCl electrode ($58.7{\pm}30.6$ vs. $81.0{\pm}19.1\;{\mu}V$, respectively), and the difference was close to statistical significance (P=0.07). Conclusions: Our electrode can be used to replace Ag/AgCl electrodes, when EEG recording is emergently required, such as in emergency rooms or in intensive care units.

Effect of Electrode Design on Electrochemical Performance of Highly Loaded LiCoO2 Positive Electrode in Lithium-ion Batteries (리튬이온 이차전지용 고로딩 LiCoO2 양극의 전극설계에 따른 전기화학적 성능연구)

  • Kim, Haebeen;Ryu, Ji Heon
    • Journal of the Korean Electrochemical Society
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    • v.23 no.2
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    • pp.47-55
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    • 2020
  • Highly loaded LiCoO2 positive electrodes are prepared to construct high-energy density lithium-ion batteries, their electrochemical performances are evaluated. For the standard electrode, a loading of about 2.2 mAh/㎠ is used, and for a high-loading electrode, an electrode is manufactured with a loading level of about 4.4 mAh/㎠. The content of carbon black as electronic conducting additive, and the porosity of the electrode are configured differently to compare the effects of electron conduction and ionic conduction in the highly loaded LiCoO2 electrode. It is expected that the electrochemical performance is improved as the amount of the carbon black increases, but the specific capacity of the LiCoO2 electrode containing 7.5 weight% carbon black is rather reduced. When the conductive material is excessively provided, an increase of electrode thickness by the low content of the LiCoO2 active material in the same loading level of the electrode is predicted as a cause of polarization growth. When the electrode porosity increases, the path of ionic transport can be extended, but the electron conduction within the electrode is disadvantageous because the contact between the active material and the carbon black particles decreases. As the electrode porosity is lowered through the sufficient calendaring of the electrode, the electrochemical performance is improved because of the better contact between particles in the electrode and the reduced electrode thickness. In the electrode design for the high-loading, it is very important to construct the path of electron conduction as well as the ion transfer and to reduce the electrode thickness.

Comparison between Two 450 mm Multi-Electrode Models

  • Park, Gi-Jeong;Lee, Yun-Seong;Yu, Dae-Ho;Lee, Jin-Won;Jang, Hong-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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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.

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