Topic
Electrical impedance
About: Electrical impedance is a research topic. Over the lifetime, 36015 publications have been published within this topic receiving 371891 citations. The topic is also known as: electrical impedance & complex impedance.
Papers published on a yearly basis
Papers
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TL;DR: These effects and the resulting amplitude envelope delays and distortion of waveforms recorded through a commercial data acquisition system and a range of tungsten microelectrodes are reported.
159 citations
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TL;DR: In this paper, a method of calculating the overall acoustic impedance of multiple layered absorbing systems is presented, and good agreement between measured (impedance tube) and computed impedances has been obtained.
158 citations
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TL;DR: In this article, an advanced model of the frequency response of a three-phase power transformer for use in conjunction with diagnostic measurements by the method of frequency response analysis (FRA) is presented.
Abstract: This paper presents an advanced model of the frequency response of a three-phase power transformer for use in conjunction with diagnostic measurements by the method of frequency response analysis (FRA). The model includes high- frequency behavior of the laminated core and the insulation through taking into account the frequency dependencies of the complex permittivity of insulation materials (paper, pressboard, and oil) and of the anisotropic complex permeability of magnetic core and conductors. A lumped parameter circuit model is used to simulate the frequency response of open-circuit impedance, short-circuit impedance, and impedance between primary and secondary windings, in which the characteristics of circuit elements are calculated by means of the finite-element method. The effect of correct representation of each circuit element on the FRA response is analyzed and discussed in comparison to measurement results on a real transformer.
157 citations
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TL;DR: This study finds that the current densities and electric fields in the ECT case are stronger and deeper penetrating than the corresponding TMS quantities but both methods show biologically interesting current levels deep inside the brain.
Abstract: A comparative, computational study of the modeling of transcranial magnetic stimulation (TMS) and electroconvulsive therapy (ECT) is presented using a human head model. The magnetic fields from a typical TMS coil of figure-eight type is modeled using the Biot-Savart law. The TMS coil is placed in a position used clinically for treatment of depression. Induced current densities and electric field distributions are calculated in the model using the impedance method. The calculations are made using driving currents and wave forms typical in the clinical setting. The obtained results are compared and contrasted with the corresponding ECT results. In the ECT case, a uniform current density is injected on one side of the head and extracted from the equal area on the opposite side of the head. The area of the injected currents corresponds to the electrode placement used in the clinic. The currents and electric fields, thus, produced within the model are computed using the same three-dimensional impedance method as used for the TMS case. The ECT calculations are made using currents and wave forms typical in the clinic. The electrical tissue properties are obtained from a 4-Cole-Cole model. The numerical results obtained are shown on a two-dimensional cross section of the model. In this study, we find that the current densities and electric fields in the ECT case are stronger and deeper penetrating than the corresponding TMS quantities but both methods show biologically interesting current levels deep inside the brain.
157 citations
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TL;DR: In this article, the rate capability of two commercial activated carbon electrodes (RP20 and MSP20) for electric double-layer capacitors was predicted using electrochemical impedance analysis.
157 citations