Nonlinear dielectric behavior of water in transmembrane ion channels: ion energy barriers and the channel dielectric constant

1992 ◽  
Vol 96 (9) ◽  
pp. 3906-3910 ◽  
Author(s):  
Michael B. Partenskii ◽  
Peter C. Jordan
Keyword(s):  
Dielectric Constant ◽  
Ion Channels ◽  
Dielectric Behavior ◽  
Energy Barriers ◽  
Ion Energy ◽  
Nonlinear Dielectric

Influence of Ca-Doping on Structural, Magnetic and Dielectric Properties of Ba3Co2-xCaxFe24O41 Hexaferrite Powders

2015 ◽  
Vol 241 ◽  
pp. 226-236 ◽  
Author(s):  
Neha Solanki ◽  
Rajshree B. Jotania
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Sol Gel ◽  
Calcium Content ◽  
Combustion Method ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Ca Doping ◽  
Auto Combustion ◽  
Magnetic And Dielectric Properties

Influence of Ca substitution on structural, magnetic and dielectric properties of Ba3Co2-xCaxFe24O41(where x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0), prepared by Sol-Gel auto-combustion method, has been investigated in present studies. The obtained powder was sintered at 950 oC for 4 hrs. in the static air atmosphere. Structural analysis of Ca-doped Ba3Co2-xCaxFe24O41powders revealed pure Z-type hexaferrite phase at low temperature. The frequency dependent dielectric constant (Єʹ) and magnetic properties such as remanent magnetization (Mr), saturation magnetization (Ms) and coercivity (Hc) were studied. It is observed that coercivity increased gradually with increase in calcium content. The real dielectric constant (Єʹ) and dielectric loss tangent (tan δ) were studied in the frequency range of 20Hz to 2MHz. The dielectric parameters for all samples show normal dielectric behavior as observed in hexaferrites. Contents of Paper

COMPARATIVE STUDY OF DIELECTRIC BEHAVIOR OF Mn0.4Zn0.6Fe2O4 NANOFERRITE BY CITRATE PRECURSOR METHOD

2008 ◽  
Vol 22 (16) ◽  
pp. 2537-2544 ◽  
Author(s):  
PREETI MATHUR ◽  
ATUL THAKUR ◽  
M. SINGH
Keyword(s):  
Particle Size ◽  
Dielectric Constant ◽  
Comparative Study ◽  
Average Particle Size ◽  
Dielectric Behavior ◽  
Average Particle ◽  
Oxidizing Agent ◽  
Precursor Method ◽  
Citrate Precursor ◽  
Citrate Precursor Method

In the present work, comparative study of the dielectric behavior of Mn 0.4 Zn 0.6 Fe 2 O 4 ferrite synthesized with and without H 2 O 2 (hydrogen peroxide) has been presented. The dc resistivity has been improved by the citrate precursor method as compared to the ceramic method, and it is further improved by the addition of H 2 O 2, which acts as a strong oxidizing agent. We have shown by means of X-ray diffraction that the resulting ferrite is made up of nanocrystallites and the average size of these nanocrystallites–calculated by Scherrer's formula–depends on the polarizer. The average particle size was found to be ~70 nm with H 2 O 2 and ~88 nm without H 2 O 2. The particle size is further confirmed by scanning electron microscopy. Both the results are found to be in good agreement. The decrease in dielectric constant and dielectric loss factor by addition of oxidizing agent is justified by inverse proportionality between the resistivity and dielectric constant. Possible mechanisms contributing to these processes have been discussed.

ON THE DIELECTRIC BEHAVIOR OF LiCo3/5Fe2/5VO4 CERAMICS

2010 ◽  
Vol 24 (07) ◽  
pp. 665-670
Author(s):  
MOTI RAM
Keyword(s):  
Activation Energy ◽  
Dielectric Constant ◽  
Frequency Dependence ◽  
Chemical Method ◽  
Arrhenius Plot ◽  
Dielectric Behavior ◽  
Tangent Loss ◽  
Low Frequencies ◽  
Different Temperatures ◽  
Tan Δ

The LiCo 3/5 Fe 2/5 VO 4 ceramics has been fabricated by solution-based chemical method. Frequency dependence of the dielectric constant (εr) at different temperatures exhibits a dispersive behavior at low frequencies. Temperature dependence of εr at different frequencies indicates the dielectric anomalies in εr at Tc (transition temperature) = 190°C, 223°C, 263°C and 283°C with (εr) max ~ 5370, 1976, 690 and 429 for 1, 10, 50 and 100 kHz, respectively. Frequency dependence of tangent loss ( tan δ) at different temperatures indicates the presence of dielectric relaxation in the material. The value of activation energy estimated from the Arrhenius plot of log (τd) with 103/T is ~(0.396 ± 0.012) eV.

Normal modes of a cylindrical waveguide in a medium with a nonlinear dielectric constant

1984 ◽  
Vol 27 (12) ◽  
pp. 1061-1065
Author(s):  
V. I. Korneev ◽  
N. N. Akhmediev ◽  
T. D. Shermergor
Keyword(s):  
Dielectric Constant ◽  
Normal Modes ◽  
Cylindrical Waveguide ◽  
Nonlinear Dielectric

scholarly journals Dielectric Properties of the System GdCo1-xFexO3Synthesized by Chemical Route (x = 0.10, 0.20)

2006 ◽  
Vol 3 (4) ◽  
pp. 313-328
Author(s):  
K. D. Mandal ◽  
L. Behera
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Constant ◽  
Chemical Method ◽  
Perovskite Oxides ◽  
Space Charge Polarization ◽  
Dielectric Behavior ◽  
Dielectric Parameters ◽  
Chemical Route ◽  
Scanning Electron

The perovskite oxides GdCo1-xFexO3(x = 0.10, 0.20) were prepared by chemical method. The dielectric behavior of compositions with x = 0.10 and 0.20 in the system GdCo1-xFexO3was studied in the temperature range 300-500 K. It is observed that dielectric constant increases with increasing Fe2+ions concentration. The frequency dependence of dielectric constant in these materials indicates that space charge polarization contributes significantly to their observed dielectric parameters. A uniform distribution of grains is observed from the microstructure by Scanning electron microscopy.

CONDUCTIVITY AND DIELECTRIC BEHAVIOR OF PLiAMPS-BASED SEMI-IPN SINGLE ION CONDUCTOR PLASTICIZED WITH POLY(SILOXANE-G-ETHYLENE OXIDE)

2012 ◽  
Vol 02 (03) ◽  
pp. 1250017
Author(s):  
WEIWEI CUI ◽  
DONGYAN TANG
Keyword(s):  
Dielectric Constant ◽  
Ionic Conductivity ◽  
Ethylene Oxide ◽  
Polymer Network ◽  
Dielectric Behavior ◽  
Interpenetrating Polymer Network ◽  
Segmental Mobility ◽  
Ion Conductor ◽  
Conductivity Variation ◽  
The Impact

Comb poly(siloxane-g-ethylene oxide) (PSi-PE) with high chain segmental mobility, as a plasticizer, was introduced into poly(lithium 2-acrylamido-2-methyl-1-propanesulfonate) (PLiAMPS)-based semi-interpenetrating polymer network single-ion conductors. The structures of PSi-PE and PLiAMPS were characterized by FTIR spectroscopy. The distribution of PSi-PE in polyelectrolyte matrix was investigated through observing the residual surface morphology of conductor membrane after being etched by toluene. AC impedance and dielectric behavior measurements were used to investigate the impact of PSi-PE on the ionic conductivity and to analyze the mechanism of conductivity variation. Compared with the unplasticized membranes, the ionic conductivity of the membrane with the addition of 35 wt.% PSi-PE was improved by 20 times. Meanwhile, the dielectric constant (ε) of the membrane was increased to 1330 and the relaxation time was decreased to 0.012 s. The changes of dielectric properties reflect directly the effect of PSi-PE on the dissociation ability of Li+ and the chain segmental mobility, which well explains the reasons of ionic conductivity variation.

Investigation of Polarization Mechanism of Relaxor Ferroelectrics

1996 ◽  
Vol 453 ◽  
Author(s):  
Z. -Y. Cheng ◽  
R. S. Katiyar ◽  
Yao Xi
Keyword(s):  
Dielectric Constant ◽  
Low Temperature ◽  
Temperature Dependence ◽  
High Precision ◽  
Relaxor Ferroelectrics ◽  
Dielectric Behavior ◽  
Polar Regions ◽  
Thermally Activated ◽  
Polarization Mechanism ◽  
Constant Maximum

AbstractAddition to thermally activated flips of polar regions in relaxor ferroelectrics, a new polarization mechanism, which originates from the vibrations (breathing) of surface of polar regions, is introduced to explain the dielectric behavior of relaxor ferroelectrics. This new mechanism plays an important role in the dielectric behavior of such materials at low temperature. Based on the above assumption and general dielectric theory, a formula is given to characterize the temperature dependence of the dielectric constant. The correctness of the formula is verified by using it to fit the experimental results of the two typical relaxors. The fitted results show that the method is of high precision and that the temperature of the dielectric constant maximum is decided by the two polarization behavior. It also indicates that the new polarization is a resonance polarization.

Dielectric Behavior of Barium Titanate/Carbon Fibers Composites

2017 ◽  
Vol 898 ◽  
pp. 2101-2106
Author(s):  
Zhong Yang Wang ◽  
Xin Yan Li ◽  
Run Hua Fan ◽  
Pei Tao Xie ◽  
Kai Sun ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Carbon Fibers ◽  
Percolation Theory ◽  
High Dielectric Constant ◽  
Volume Fraction ◽  
Dielectric Behavior ◽  
Lower Volume Fraction ◽  
Lower Volume ◽  
High Dielectric

Conductor–insulator composites have been extensive researched for high dielectric constant. Most of them concentrated on metal polymers or metal ceramics. Barium titanate–carbon fibers composites were prepared by using a solid state reaction process with carbon fibers contents ranging from7 vol% to 23 vol%. Due to the high-aspect-ratio of carbon fiber, it was easy to produce a conducting network at much lower volume fraction. FESEM images illustrated that the carbon fibers influenced the densification and microstructure of the ceramics. Besides, addition of carbon fibers led to increase in dielectric permittivity, also had effects on the dielectric loss and ac conductivity. The dielectric and conductivity properties as a function of carbon fibers volume fraction were explained by the percolation theory.

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