نتایج جستجو برای: electric impedance measurement

تعداد نتایج: 606117  

2014
Nan Li Wei Wang

The cell impedance analysis technique is a label-free, non-invasive method, which simplifies sample preparation and allows applications requiring unmodified cell retrieval. However, traditional impedance measurement methods suffer from various problems (speed, bandwidth, accuracy) for extracting the cellular impedance information. This thesis proposes an improved system for extracting precise c...

2000
A. Yúfera G. Leger E. O. Rodríguez-Villegas J. M. Muñoz A. Rueda A. Ivorra R. Gomez N. Noguera J. Aguiló

In this paper, the design of aa Integrated Circuit (IC) for the measurement of tissue impedance is presented. The chip is intended to be used in monitoring biomedical parameters in living bodies. Tissue impedance is one of these parameters which allows ischemia monitoring. The designed IC is used in a four-electrode based set-up in order to minimize the effect of electrode-electrolyte interface...

2013
Ingrid Anne P. Nazareth Rajendra S. Gad Gourish M. Naik

This paper proposes a non invasive measurement technique to estimate the level of glucose by impedance measurement. This work presents a study of the varying concentrations of glucose using RF Impedance Spectroscopy (RIS). A cell was designed to create body environmental conditions having glucose concentration comparable to body glucose of a healthy person. The changes in the measured absorptio...

2011
Martin RANDUS Karel HOFFMANN

The rapid progress in nanoelectronics showed an urgent need for microwave measurement of impedances extremely different from the 50Ω reference impedance of measurement instruments. In commonly used methods input impedance or admittance of a device under test (DUT) is derived from measured value of its reflection coefficient causing serious accuracy problems for very high and very low impedances...

Journal: :Physiological measurement 2003
Guoya Dong Richard H Bayford Shangkai Gao Yoshifuru Saito Rebecca Yerworth David Holder Weili Yan

This paper presents a new application of a generalized vector sample pattern matching (GVSPM) method for image reconstruction of conductivity changes in electrical impedance tomography. GVSPM is an iterative method for linear inverse problems. The key concept of the GVSPM is that the objective function is defined in terms of an angular component between the inner product of the known vector and...

Journal: :Electroanalysis 2007
Jonathan S Daniels Nader Pourmand

Impedance biosensors are a class of electrical biosensors that show promise for point-of-care and other applications due to low cost, ease of miniaturization, and label-free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label...

Journal: :Physiological measurement 2001
M Molinari S J Cox B H Blott G J Daniell

Adaptive mesh refinement techniques can be applied to increase the efficiency of electrical impedance tomography reconstruction algorithms by reducing computational and storage cost as well as providing problem-dependent solution structures. A self-adaptive refinement algorithm based on an a posteriori error estimate has been developed and its results are shown in comparison with uniform mesh r...

Journal: :Physiological measurement 2004
William R B Lionheart

We review developments, issues and challenges in electrical impedance tomography (EIT) for the 4th Conference on Biomedical Applications of Electrical Impedance Tomography, held at Manchester in 2003. We focus on the necessity for three-dimensional data collection and reconstruction, efficient solution of the forward problem, and both present and future reconstruction algorithms. We also sugges...

Journal: :Liquid Crystals 2021

Dielectric (impedance) spectroscopy of liquid crystals is a powerful experimental technique. It especially essential because in many applications are still controlled by the electric field. In this paper, problems with high frequency (>1 MHz) measurements classical (in shape flat capacitor) measuring cells discussed. The procedure for overcoming measurement difficulties was presented and applie...

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