نتایج جستجو برای: electric impedance

تعداد نتایج: 175951  

2001
D. Kovačić A. Šantić

In Electrical Impedance Tomography (EIT) measurement sinusoidal currents are applied on a surface of the human body and voltage response is measured in order to reconstruct conductivity distribution in a body cross-section. We have constructed an experimental system for EIT measurement based on voltage response to short current pulses. In this case resistive components of body impedance are mea...

2017

Electrical impedance tomography (EIT) is a noninvasive type of medical imaging in which the electrical conductivity, permittivity, and impedance of a part of the body is inferred from surface electrode measurements and used to form a tomographic image of that part. Electrical conductivity varies considerably among various biological tissues (absolute EIT) or the movement of fluids and gases wit...

Journal: :Physiological measurement 2015
Pascal O Gaggero Andy Adler Andreas D Waldmann Yasin Mamatjan Jörn Justiz Volker M Koch

An automated test system and procedure is proposed, designed to enable systematic testing of electrical impedance tomography (EIT) devices. The system is designed to calculate reliable, repeatable and accurate performance figures of merit of an EIT system using a saline phantom and an industrial robot arm. Applications of the test system are to compare EIT devices against requirements, or to he...

2000
Zsolt Kerner Tamás Pajkossy

The interfacial impedance of polycrystalline solid electrodes in the absence of Faradaic reactions is never purely capacitive; the deviation from ideal capacitive behaviour is usually larger on rough electrodes than on smooth ones. We present qualitative experiments to demonstrate that the frequency dependence of capacitance on solid electrodes is due to the atomic scale inhomogeneities rather ...

2012
Rainer Müller

Surface charges play a major role in DC circuits because they help generate the electric field and potential distributions necessary to move the charges around the circuit. Unfortunately, it is generally regarded as a difficult task to determine the surface charge distribution for all but the simplest geometries. In this paper, we develop a graphical method for the approximate construction of s...

Journal: :Biomedizinische Technik. Biomedical engineering 2002
C H Riedel M A Golombeck O Dössel

The measurement of the impedance of biological tissue can be a non-invasive method to find new data of diagnostic relevance. A system for a non-contact measurement of the electrical impedance of biological tissue is presented. The system consists of an excitation coil and two sensing coils, an upper and a lower coil. If the two sensing coils are coupled it can be used as a gradiometer coil. Num...

2001
Peng Zou Liling Xiao Xiang Sun Wei Gai

One disadvantage of conventional iris-loaded accelerating structures is the high ratio of the peak surface electric field to the peak axial electric field useful for accelerating a beam. Typically this ratio Es/Ea ≥ 2. The high surface electric field relative to the accelerating gradient may prove to be a limitation for realizing technologies for very high gradient accelerators. In this paper, ...

2007
Il-kwon Kim Dae-won Park Su-yeon Choi Gyung-suk Kil

In this paper, we simulated series arc on electric heaters, vacuum cleaners and incandescent lamps controlled by a dimmer to analyze the characteristics of series arc that causes electric fires. A high pass filter (HPF) was designed to detect arc signal only. The HPF consists of 2-stage coupling capacitors and detection impedance, and its low cut-off frequency of -3 dB was estimated to 3 kHz. B...

Journal: :Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology 2002
J Clementy D Rouves S Garrigue S S Barold P Jaïs M Haïssaguerre

For physicians who are not familiar with the electrical basis of cardiac stimulation, high impedance leads previously (10 years ago) considered as bad electrodes (high voltage) are now considered as the 'epitome' of lead technology (low energy drain): clearly impedance is not a good parameter for characterizing the qualities of a pacing lead. Using a simplified approach to the electrostimulatio...

2012
Antonis Orphanou Toshishige Yamada Cary Y. Yang

Modeling of carbon nanotube ultracapacitor (CNU) performance based on simulation of electrolyte ion motion between cathode and anode is described. Using a molecular dynamics (MD) approach, the equilibrium positions of electrode charges interacting through Coulomb potential are determined, which in turn yield the equipotential surface and electric field associated with the capacitor. With an app...

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