Electrical Impedance Measurements

Lyden et al. [92] used in situ electrical impedance measurements to investigate the role of disorder in polysulfide PEC with electrodeposited, polycrystalline CdSe photoanodes. Their results were consistent with disorder-dominated percolation conduction and independent of any CdS formed on the anode surface (as verified by measurements in sulfide-free electrolyte). The source of the observed frequency dispersion was located at the polycrystalline electrode/electrolyte interface. 

I.H. Campbell, D.L. Smith, and J.P. Ferraris, Electrical impedance measurements of polymer light emitting diodes, Appl. Phys. Lett., 66 3030-3032, 1995. 

This model, when applied to Nation as a function of water content, indicated a so-called quasi-percolation effect, which was verified by electrical impedance measurements. Quasi-percolation refers to the fact that the percolation threshold calculated using the single bond effective medium approximation (namely, x = 0.58, or 58% blue pore content) is quite larger than that issuing from a more accurate computer simulation. This number does not compare well with the threshold volume fraction calculated by Barkely and Meakin using their percolation approach, namely 0.10, which is less than the value for... 

On the other hand, electrical impedance measurement of bacterial suspensions (.Listeria innocua) was carried out on a Si-glass chip. This method was used to perform a cell viability test. This is because the metabolic products produced from viable cells modify the ionic strength of a low-conductivity medium, significantly altering its electrical characteristics. Later work also involved the detection of the presence of small numbers of bacterial cells in a Si chip 100 L. innocua cells, 200 L. monocytogenes cells, and 40 E. coli cells [93,885], In another report, impedance spectroscopy has been used for analysis of erythrocytes in a glass-polyimide chip [886]. 

FIGURE 32.6 Age related comparisons of friction and electrical impedance. No significant differences were apparent between old and young skin on the volar forearm. Within each category, the proximal right arm friction and electrical impedance measurements were different from the distal right arm (P <. 001). Reproduced from Sivamani et al24... 

Electrical impedance measurements for silicon etching in HF have been used to analyze the potential distribution at the interface [72, 73, 75, 79, 80]. Analysis of these data has resulted in insight into the kineties of the dissolution process and the potential distribution at the silicon/HF interface. The characteristic features of the... 

Deurenberg, R, Westerterp, K., and Wierik, E. (1994). Between-laboratory comparison of densitometry and bio-electrical impedance measurements. Brit.. Nutr. 71,309-316. 

Electrical impedance measurements are extremely valuable in many applications including measurements of superconductivity, magnetoresistivity, ferroelectric, and... 

The fundamental kinetics and transport properties of plasma processes are reviewed and applied to polysilicon etching in Cla discharges. The relative neutral flux, ion flux, and ion energy is critical in controlling the directionality of the etching process. The electron density and energy have been estimated from electrical impedance measurements of Cl2 discharges. 

Another interesting photoelectroanalytical method for the characterization of polymer films is a method which might be called photoimpedance spectrum. A small-amplitude sine-wave signal is applied to the working electrode and the resulting absorbance response is recorded at different frequencies. Alternatively, several frequencies are applied simultaneously and the response analyzed by using Fourier transform. The main advantage compared with the conventional electrical impedance measurements is naturally that only faradaic current... 

Electrical impedance measurements are essential in semiconductor dissolution studies. Under depletion conditions, a change in applied potential will usually give rise to a change in the potential drop within the semiconductor. Impedance measurements combined with... 

Fukuda, J., Peach, C.J., Spiers, C.J. Nakashima, S. (2009a). Electrical impedance measurement of hydrous microcrystalline quartz. Journal of Mineralogical and Petrological Sciences, Vol. 104, pp. 176-181... 

Ivorra, A., Rubinsky, B., 2007. In vivo electrical impedance measurements during and after electroporation of rat liver. Bioelectrochemistry 70, 287—295. 

In the case of the impedimetric IME sensor, the two sets of electrodes of the IME can be two poles in a two-electrode configuration for electrical impedance measurements. Figure 4 shows 4a a picture, 4b a schematic, 4c the equivalent circuit model for the IME device, and 4d the Bode plot of the electrochemical impedance spectram obtained in aqueous 0.01 M phosphate-buffered saline containing 10 mM ferricyanide at room temperature. The equivalent circuit for the IME device in Fig. 4c consists of an ohmic resistance (/ s) of the electrolyte between two sets of electrodes and the double-layer capacitance (Cdi), an electron transfer resistance (Ret), and Warburg impedance (Z, ) around each set of electrodes [2], Rs and the two branch circuits are connected... 

Depending upon the products, there might be very narrow margins to that exercise and the endpoint temperatures, velocities of cooling, and rewarming need to be known very accurately by previous laboratory determinations such as differential thermal analysis (DTA) or differential scanning calorimetry (DSC), low temperature electric impedance measurements, velocity of crystallization in the supercooled state, etc. 

Figure 1. Anatomical placement of the 6 points where electrical impedance measurements were taken. Segments and approximate length estimations according to [14] and [15].

D. Miranda, S. Lopez-Rivera. (2008) Determination of Cole-Cole parameters using only the real part of electrical impedivity measurements. Physiological Measurement, vol. 29, pp. 669-683. 

Others physiological quantities estimated from electrical impedance measurement include blood flow, stroke volume, autonomic nervous system activity, muscle contraction, eye movement, endocrine activity and the activity of brain cells [4]. 

Ivorra A, Gomez R, Noguera N (2003) Minimally invasive silicon probe for electrical impedance measurements in small animals. Biosensors and Bioelectronics 19 391-399. 

Electrical impedance measurements applied to living cells confirm the main role played by the plasmalemma interface. Presently, it is, however. 

Ivoira, A., G6mez, R., Noguera, N., Villa, R., Sola, A., Palacios, L., Hotter, G., AguUo, J., 2003. Minimally invasive silicon probe for electrical impedance measurements in small animals. Biosens. Bioelectron. 391, 393-399. 

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