Showing papers on "Conductivity published in 1983"
TL;DR: In this article, conductivity, N.M.R. and D.S.C. measurements in two P(EO) complexes are presented, and the elastomeric phase is shown to be responsible of the ionic conductivity at all temperatures.
967 citations
TL;DR: In this article, the fundamental aspects of ceramic humidity sensors in relation to humidity sensitivity, pore size distribution and effect of CO 2 and other gases are discussed with the experimental results of several fabricated sensors.
319 citations
TL;DR: In this paper, the electrical conduction in the solid proton electrolyte based on SrCeO3 was studied under water-containing atmospheres at high temperatures and the change of conductivity was measured systematically as a function of the concentration of the dopant or of the partial pressures of water vapor and oxygen.
270 citations
TL;DR: In this article, the conductivity as a function of donor density and uniaxial stress in bulk samples of phosphorus-doped silicon was measured and the transition from metal to insulator is continuous, but sharper than predicted by scaling theories of localization.
Abstract: Millikelvin measurements of the conductivity as a function of donor density and uniaxial stress in bulk samples of phosphorus-doped silicon establish that the transition from metal to insulator is continuous, but sharper than predicted by scaling theories of localization The divergence of the dielectric susceptibility as the transition is approached from below also points out problems in current scaling theories The temperature dependence of the conductivity and the magnetoresistance in the metal indicate the importance of Coulomb interactions in describing the behavior of disordered systems
238 citations
TL;DR: In this article, a polymer solid electrolyte was prepared from the hybrid of poly(vinylidene fluoride) and lithium perchlorate, which was obtained as films having a thickness of about 0.1 mm and high lithium ionic conductivity.
232 citations
TL;DR: In this paper, the authors define a decoupling index R τ, 1 τ 13, which describes how well the (fast ion) conducting modes are decoupled from the amorphous matrix.
231 citations
TL;DR: A relationship between the a.c. and d.c components of ionic conductivity, established for single crystal Na β-alumina, is critically examined in this article.
225 citations
IBM1
TL;DR: The mechanical and conducting properties of free-standing films of polypyrrole toluenesulfonate depend on the preparation conditions as mentioned in this paper, and they show a variation of two orders of magnitude in the conductivity and of a factor of three in the tensile strength.
Abstract: The mechanical and conducting properties of free-standing films of polypyrrole toluenesulfonate depend on the preparation conditions. Films prepared in aqueous ethylene glycol solvent mixtures show a variation of two orders of magnitude in the conductivity and of a factor of three in the tensile strength.
224 citations
TL;DR: In this paper, it was shown that the conductivity prefactor of β-alumina is anomalously large at low temperatures and this is caused by an unexpectedly high ion hopping rate.
Abstract: We wish to draw attention to the fact that the conductivity prefactor of arguably the most important fast ion conductor, β″-alumina, is anomalously large at low temperatures and we show here that this is caused by an unexpectedly high ion hopping rate. In addition, similar results are found in the Na/Ag β-alumina system and these may be of significance in contributing to the understanding of the mixed alkali effect in general.
208 citations
TL;DR: In this article, the authors showed that organic polar materials with lower viscosity such as N, N -dimethyl formamide or γ-butyrolactone strongly contributed to the improvement of lithium ionic conductivity.
161 citations
TL;DR: It is suggested that the olarizability observed at audio and radiowave frequencies is in part sssociated with the collagen phase, although other interfacial polarization effects can also be present.
Abstract: The dielectric permittivity and electrical conductivity of freshly excised and formalin fixed samples of rat femoral bone were determined over a frequency range of 10 Hz-100 MHz. Impedance measurements were performed in the frequency domain using a vector impedance meter and an impedance analyzer. The results of these measurements show that the conductivity of fixed and fresh bone is nearly independent of frequency below 100 kHz, with the conductivity of fresh bone being two to three times greater than that of the fixed sample. At higher frequencies, the conductivity increases as a power function of frequency. The permittivity of bone reaches very high values at low frequencies, but decreases rapidly with increasing frequencies and approaches a limiting value of about ten. This high-frequency limit is consistent with the water content of the tissue, and with the permittivity of the anhydrous matrix. It is suggested that the olarizability observed at audio and radiowave frequencies is in part sssociated with the collagen phase, although other interfacial polarization effects can also be present.
TL;DR: In this paper, the effect of pyrochlore order in solid solutions with the defect fluorite structure was studied and the amount of order was changed by various heat treatments or by varying the cation composition.
TL;DR: The ionic conductivity of Li 3 N crystals doped with various metal ions (magnesium, copper and aluminum) or hydrogen has been investigated in this paper, where a model is proposed for the action of hydrogen whereby the Li-N bonds next to an NH 2-group are weakened thereby facilatating the creation of Li + Frenkel defects and the vacancy migration.
TL;DR: In this article, a space charge model for electrolyte transport in charged capillary pores was examined experimentally with aqueous solutions of alkali chlorides and in track-etched mica membranes.
Abstract: A space‐charge model for electrolyte transport in charged capillary pores was examined experimentally with aqueous solutions of alkali chlorides and in track‐etched mica membranes. The model combines the Gouy‐Chapman view of the double layer with the Nernst‐Planck and Navier‐Stokes transport equations. The pores of experimental membranes were uniform capillaries with a well‐characterized cross section. The pore sizes ranged from an order of magnitude smaller to an order of magnitude larger than the Debye screening lengths of solutions. Three independent quantities were measured: streaming potential, for which an applied pressure across the membrane is the driving force for transport; pore conductivity, for which an applied electrical potential is the driving force; and concentration potential, for which an electrolyte concentration difference is the driving force. Data follow the trends of model predictions but indicate that chloride ions affect the pore wall charge. For monovalent cations, the pore wall charge deduced from pore conductivity measurements yielded theoretical predictions for the streaming potential and for the concentration potential that agree quite well with the data. Such agreement was not obtained with Mg2+, probably because these divalent cations adsorbed onto the negative pore wall. We conclude that, in the absence of strong interaction between the charged pore wall and free ions in solution, the model is quantitatively accurate for pores larger than 30A in radius and for aqueous electrolyte concentrations of 0.1M or lower.
TL;DR: In this article, the electrochemical reversibility of thick oxide films formed on Ir electrodes by potential cycling is examined in relation to the initial monolayer surface oxidation processes, and it is suggested that film growth which occurs on cycling is the result of accumulation of oxide produced in an underlying monoline during each anodic sweep but which is left in an incompletely reduced state on each following cathodic sweep, due to irreversibility.
TL;DR: In this paper, the authors present mean values of conductivity measurements collected from the literature for dry mafic and silicic rocks in the temperature range of 500°C to 1000°C.
Abstract: This study provides values of electrical conductivity of possible lower crustal materials to assist interpretation of lower crustal magnetotelluric soundings. We present mean values of conductivity measurements collected from the literature for dry mafic and silicic rocks in the temperature range of 500°C to 1000°C. We observe statistically significant differences between rock types: mafic rocks are better conductors than granites by about half an order of magnitude and within the mafic group, aphanitic (fine‐grained) rocks have higher conductivity than phaneritic (coarse‐grained) ones. “Best‐fitting” curves of log conductivity versus temperature are presented for each rock type to show mean log conductivity values together with standard deviations so that most probable temperature ranges can be inferred from conductivity. Because the laboratory rocks are dry, their conductivities are lower at a given temperature than they would be if fluids or volatiles were present; hence any temperatures inferred from ...
TL;DR: In this article, the electrical conductivity of hybrid films consisting of polyacrylonitrile (PAN), ethylene carbonate (EC), and LiClO4 was investigated.
Abstract: The electrical conductivity of hybrid films consisting of polyacrylonitrile (PAN), ethylene carbonate (EC), and LiClO4 was investigated. In these films, EC and LiClO4 are found to be molecularly dispersed in PAN, forming solid solutions over a wide composition range. The ionic character of the electrical conductivity is demonstrated. The conductivity is not correlated with the content of LiClO4 or of PAN, but primarily with the mole ratio [EC]/[LiClO4] in the films. An increase in the [EC]/[LiClO4] ratio enhances the conductivity. When the ratio is about 2, the conductivity attains 10−4–10−5 S cm−1 at 25°C. This change in conductivity results from a change in carrier mobility. PAN makes the films solid without decreasing the carrier mobility. In the hybrid films, the carrier mobility and the macroscopic viscosity are not related by Walden's rule. The high conductivity is due to regions in the film characterized by a low microscopic viscosity. This is determined by the mole ratio [EC]/[LiClO4] and largely controls the carrier mobility.
TL;DR: The electrical conductivity of these glasses has been measured over a temperature range (−50°C− + 50°C) and for various compositions by the complex impedance diagram method as mentioned in this paper.
Abstract: Ag2S forms with GeS2 stable glasses over a wide range of compositions (0–55% Ag2S mol%) In the same system, more complex glasses obtained by dissolving silver iodide have been synthesized with up to 50 mol% AgI Raman spectra are presented and a vibrational assignment in terms of bridging and non-bridging sulfur has been made The electrical conductivity of these glasses has been measured over a temperature range (−50°C− + 50°C) and for various compositions by the complex impedance diagram method At 25°C, the conductivity reached a maximum value of 6 × 10−3 Ω−1 cm−1 Whatever the glass used, the same limit value of conductivity (σ − 10 su−2 Ω −1 cm −1 ) and activation energy ( E σ ⋍ 025 eV ) are obtained for the highest content of silver iodide A conduction mechanism is proposed
TL;DR: In this paper, a new method was established to estimate the foaming properties of proteins from the conductivity of foams using a simple apparatus that consisted of a glass column with conductivity cell.
Abstract: A new method was established to estimate the foaming properties of proteins from the conductivity of foams using a simple apparatus that consisted of a glass column with the conductivity cell. A close correlation was observed between the initial conductivity of foams and the foam volumes of heat-denatured ovalbumins or 11 native proteins, suggesting that the initial conductivity of foams can be used as a measure of foaming power. In addition, a close correlation was obtained between the foam stability determined from changes in the conductivity and foam volume with time of heat-denatured ovalbumins or 11 native proteins, suggesting that foam stability also can be estimated from changes in the conductivity of foams. The advantages of the conductivity measurements are to determine the foaming properties more simply and accurately than the currently used methods.
TL;DR: The conductivity and dielectric constant display strongly dispersive behavior with three distinct relaxation regions over the frequency range from less than 100 Hz to nearly 100 GHz.
Abstract: The electrical properties of blood and its constituents are reviewed over the frequency range from less than 100 Hz to nearly 100 GHz. The conductivity and dielectric constant display strongly dispersive behavior with three distinct relaxation regions. Mechanism responsible for this behavior are stated and possible applications indicated.
TL;DR: In this paper, the state of knowledge on the behavior of ground wire electrodes under impulse currents due to lightning strokes is outlined. And the influence of ground characteristics, size of buried conductors, and current wave-shape and intensity are discussed.
Abstract: The state of knowledge on the behavior of ground wire electrodes under impulse currents due to lightning strokes is outlined. The influence of ground characteristics, size of buried conductors, and current wave-shape and intensity are discussed.
TL;DR: In this paper, the effects of change of the molecular weight of the diglycidyl ether on the dielectric relaxation are small in comparison with the changes observed on the introduction of water into the matrix.
Abstract: Dielectric measurements are reported on amine-cured epoxy resin samples over a frequency range from 200 Hz to 200 kHz and a temperature range from −60°C to 70°C as a function of molecular weight of the diglycidyl ether and water content. The effects of change of the molecular weight of the diglycidyl ether on the dielectric relaxation are small in comparison with the changes observed on the introduction of water into the matrix. Analysis of the data indicates the presence of cluster—free and bound—molecularly dispersed water. The former are presumed to be found in voids and cavities which arise in curing powder samples. The conductivity of the water-doped samples reflects the mobility of the water and is compared with the predictions of theories for amorphous materials.
Patent•
02 Nov 1983TL;DR: In this article, changes in conductivity of the polymer-catalyst transducers as a result of electron density changes are measured to provide an indication of a particular constituent present in the sample.
Abstract: Polymer-catalyst transducers are used for detecting one or more constituents in a sample. Changes in conductivity of the polymer-catalyst transducers as a result of electron density changes are measured to provide an indication of a particular constituent present in the sample. Such conductivity changes can be measured using a conductivity meter. The polymer-catalyst transducers are particularly useful for the determination of glucose in whole blood.
TL;DR: The concentrations of fixed ion in Nafion® membranes have been calculated based on both the homogeneous model and the ion cluster model while the concentrations of co-ion were calculated from the Donnan expression as mentioned in this paper.
Abstract: The concentrations of fixed ion in Nafion® membranes have been calculated based on both the homogeneous model and the ion cluster model while the concentrations of co‐ion were calculated from the Donnan expression. The experimental results on the concentrations of co‐ion reveal that the ions in this material do form clusters and the membrane also exhibits a strong Donnan exclusion effect. The ionic mobilities obtained from the conductivity and diffusivity studies are in fairly good agreement. Strong acidity coupled with high proton mobility in this membrane provide an important solid polymer electrolyte for a variety of electrochemical applications. The impact of polymer morphology on cell performance is also discussed.
TL;DR: In this article, the tracer diffusion coefficients of 22Na and 137Cs, and the electrical conductivity have been measured in the (Na, Cs)2O:3SiO2 glasses as a function of temperature and Cs/Na ratio.
Abstract: The tracer diffusion coefficients of 22Na and 137Cs, and the electrical conductivity have been measured in the (Na, Cs)2O:3SiO2 glasses as a function of temperature and Cs/Na ratio. Complex impedance analysis was used for the conductivity measurements. The Haven ratio at 396.5°C increases from 0.3–0.4 in single-alkali glasses to 0.8 for the mixed-alkali compositions. The results are explained in terms of a single-jump mechanism; interactions between alkali ions and non-bridging oxygen ions, and between different alkali ions, produce the observed correlation effects.
TL;DR: In this article, the ideal conductivity of a one dimensional (1-D) carbon based metal has been studied and compared with previous results on graphite intercalation compounds (GICs).
TL;DR: In this article, the electrical conductivity at low temperatures of bulk samples of Si:P under uniaxial stress controlled to bring the samples within 0.1% of the metal-insulator transition was measured.
Abstract: We present measurements of the electrical conductivity at low temperatures of bulk samples of Si:P under uniaxial stress controlled to bring the samples within 0.1% of the metal-insulator transition. As the metal approaches the critical point, we find that the power law of the temperature correction to the conductivity predicted for weak Coulomb interactions continues to fit, but that its sign, size, and range of validity change. Its size defines a diffusion temperature which tends towards zero at the critical density, at which point the power law itself appears to change.
TL;DR: In this article, the ionic conductivity of evaporated Li2OB2O3 thin films has been studied and the correlation between structure and conductivity is also discussed.
Abstract: The ionic conductivity of evaporated Li2OB2O3 thin films has been studied. These thin films were found to show a considerably high ionic conductivity of 1 × 10−7 Ω−1 cm−1 at room temperature. The conductivity increases with increasing Li content and exhibits a maximum value near 3Li2O·B2O3. The structure of these films was determined using infrared absorption and laser Raman scattering spectroscopy. Using the results, the correlation between structure and conductivity is also discussed.
01 Jun 1983
TL;DR: In this article, an octahedral site small polaron mechanism was found to be dominant over the entire temperature range (Ea = 0.1136 eV) at elevated temperatures.
Abstract: Electrical conductivity in magnetite has been studied experimentally as a function of temperature and oxygen activity between 560 and 1400°C. The results indicate that above TC (=575°C) an octahedral site small polaron mechanism is dominant over the entire temperature range (Ea = 0.1136 eV). By comparing data on electrical conductivity and thermoelectric power, a second (small polaron) mechanism (Ea = 0.714 eV) is detected at elevated temperatures. Additionally, equilibrium constants for the cation vacancy formation are derived from fitting the conductivity isotherms as a function of oxygen activity. These agree well with values determined thermogravimetrically.