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The resistive switching behaviors are investigated in highly silicon-rich Si[O.sub.x] (x = 0.73) films, which are deposited using the plasma enhanced chemical vapor deposition method. For the Pt/Si[O.sub.0.73]/Pt structures, after the forming process the reset voltages (~0.7 V) are lower than the set voltages (~1.7 V). The metal-free structures [N.sup.+]-Si/Si[O.sub.0.73]/[N.sup.++]-Si/Pt show almost the same switching behaviors as those of Pt/Si[O.sub.0.73]/Pt structures, demonstrating an intrinsic resistive switching mechanism. We use the silicon dangling bonds (Si-DBs) percolation model to explain this. It is based on the biasing electric field decreasing the bond strength and leading to the breakage of Si-O bonds in Si[O.sub.x] films. Consequently the new Si-DBs are created and will contribute to form the dangling bonds percolation path. The temperature dependence of forming voltages is investigated. The forming voltages show no obvious changes and the forming process will occur as soon as the sweeping voltage reaches ~10.5 V, even if the temperature decreases to 5.5 K. It indicates that the electric field plays an important role during the forming processes. Moreover, through the analysis of X-ray photoelectron spectroscopy and electron spin resonance signals, it can be concluded that the *Si≍[Si.sub.3] and *Si≍[Si.sub.2]O DBs centers are the main components in Si-DBs percolation path of Si[O.sub.0.73] films. PACS Nos.: 71.30.+h, 71.55.Jv, 72.20.Ee. Nous analysons la commutation resistive dans des films riches en silicium Si[O.sub.x] (x = 0.73) qui sont deposes par depot chimique en phase vapeur avec traitement au plasma. Pour les structures de Pt/Si[O.sub.0.73]/Pt apres le procede de formation, les voltages de reinitialisation (~0.7 V) sont plus bas que les voltages d'initialisation (~1.7 V). Les structures sans metal [N.sup.+]-Si/Si[O.sub.0.73]/[N.sup.++]/Pt montrent pratiquement les memes comportements de commutation que les structures Pt/Si[O.sub.0.73]/Pt, ce qui demontre le caractere intrinseque du mecanisme de commutation. Nous utilisons le modele de percolation a liaisons pendantes (Si-DBs) pour expliquer ce resultat. Dans ce modele, un champ electrique de polarisation cause une diminution de la force de la liaison et mene a un bris du lien Si-O dans les films de Si[O.sub.x]. Consequemment, les nouveaux Si-DBs sont crees et vont contribuer a former la trajectoire de percolation des DBs. L'etude de la dependance en temperature du voltage de formation montre qu'il ne subit aucun changement evident et que la formation debute aussitot que le balayage en voltage atteint ~10.5 V, meme si la temperatura descend a 5.5 K. Cela souligne l'importance du role du champ electrique dans le processus de formation. De plus, la spectrometrie photo-electronique X et la resonance de spin electronique indiquent que les centres DBs *Si≍[Si.sub.3] et *Si≍[Si.sub.2]O sont les composants majeurs de la percolation Si-DBs des films de Si[O.sub.0.73]. [Traduit par la Redaction], 1. Introduction Recently, the resistive switching characteristics of silicon oxide (Si[O.sub.x]) materials have increasingly been studied. As a conventional dielectric gate material and the isolation layer of metal interconnect, Si[O.sub.x] [...]

We compare methods for estimating the residual resistivity ratio (RRR) of high-purity niobium and investigate the effects of using different functional models. RRR is typically defined as the ratio of [...]

This manuscript describes a straightforward fabrication process for embedding Ag/AgCl electrodes within a two-layer poly(dimethylsiloxane) (PDMS) microfluidic chip where an upper and a lower channel are separated by a semiporous membrane. This system allows for the reliable real-time measurement of transendothelial and transepithelial electrical resistance (TEER), an accepted quantification of cell monolayer integrity, across cells cultured on membranes inside the microchannels using impedance spectroscopy. The technique eliminates the need for costly or specialized microelectrode fabrication, enabling commercially available wire electrodes to easily be incorporated into PDMS microsystems for measuring TEER under microfluidic environments. The capability of measuring impedance across a confluent cell monolayer is confirmed using (i) brain-derived endothelial cells (bEND.3), (ii) Madin Darby Canine Kidney Cells (MDCK-2), and mouse myoblast (C2C12) (all from ATCC, Manassas, VA). TEER values as a function of cell type and cell culture time were measured and both agree with previously published values from macroscale culture techniques. This system opens new opportunities for conveniently resolving both transendothelial and transepithelial electrical resistance to monitor cell function in real-time in microfluidic cell cultures. 10.1021/ac9029345

Electrical impedance measurements in the laboratory on silicate melts are used to interpret magnetotelluric anomalies. On the basis of 2- and 4-electrode measurements, we show that the influence of the electrodes of the 2-electrode system on the measured resistivity can be of significant importance for low-resistivity melts and increases with temperature. At 1400[degrees]C, the resistivity of very conductive melts measured with two electrodes can reach six times the resistivity value measured with four electrodes. A short-circuit experiment is needed to correct the 2-electrode data. Electrodes contribution is also estimated for samples from other studies, for which the resistance of the electrical cell can be as high as the resistance of the sample. A correction of the resistivity data from the literature is proposed and values of the corresponding Arrhenian parameters are recommended. Keywords: Impedance measurements, resistivity, melts DOI: 10.2138/am.2010.3314