DIELECTRIC RELAXATION IN LIQUIDS: I. THE REPRESENTATION OF RELAXATION BEHAVIOR

1961 ◽  
Vol 39 (3) ◽  
pp. 571-594 ◽  
Author(s):  
D. W. Davidson
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Superposition Principle ◽  
Relaxation Behavior ◽  
Complex Dielectric Constant ◽  
Published Data ◽  
Relaxation Processes ◽  
High Frequencies ◽  
Arc Characteristics ◽  
The Individual

Methods are described for the determination from experimental data of the parameters used in the skewed-arc representation in the complex dielectric constant plane of dielectric relaxation in liquids. Graphs give the frequency dependence of the real and imaginary parts of the dielectric constant predicted by the skewed-arc equation. Evidence, which includes an analysis of published data and of some new data, is presented for the frequent occurrence of this type of relaxation behavior in liquids. The resolution of the effects of different relaxation processes is discussed.The recent defect-diffusion model of Glarum is found to lead, under some conditions, to complex dielectric constant loci which are practically indistinguishable from skewed-arc loci over much of the frequency range of dispersion. It predicts departures from skewed-arc behavior at relatively high frequencies which are possibly related to experimentally observed departures.It is concluded that skewed-arc characteristics arise from the presence of co-operative relaxation processes, possibly aided by the diffusion of disordered regions, in which the individual mechanisms of relaxation cannot be resolved by application of the superposition principle.

Dielectric Relaxation Properties in Colossal Dielectric Constant Material Sr0.9Ba0.1Ti0.9Ru0.1O3

2011 ◽  
Vol 298 ◽  
pp. 23-28 ◽  
Author(s):  
Tong Wei ◽  
Qing Jun Zhou ◽  
Qing Gong Song ◽  
Chuan Zhen Zhao ◽  
Jun Ming Liu
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Relaxation Behavior ◽  
Color Centers ◽  
Complex Perovskite ◽  
Impedance Analyzer ◽  
Clear Link ◽  
Dielectric Relaxation Behavior ◽  
Colossal Dielectric Constant ◽  
Dielectric Relaxation Properties

We investigated the colossal dielectric constant behavior and interesting dielectric relaxation over broad temperature and frequency ranges in complex perovskite Sr0.9Ba0.1Ti0.9Ru0.1O3 ceramics by using HP4294 impedance analyzer. Through the discussion, there exists a clear link between the dielectric relaxation and the sample conductivity. It’s believed that hopping of electrons between color centers not only produce conductivity but also give rise to dielectric relaxation behavior.

scholarly journals Relaxation Dynamics of Ethanol and N-Butanol in Diesel Fuel Blends from Terahertz Spectroscopy

2021 ◽  
Vol 42 (7) ◽  
pp. 772-792
Author(s):  
Rayda Patiño-Camino ◽  
Alexis Cova-Bonillo ◽  
José Rodríguez-Fernández ◽  
Teresa P. Iglesias ◽  
Magín Lapuerta
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Full Range ◽  
Pure Component ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Relaxation Dynamics ◽  
Terahertz Time Domain Spectroscopy ◽  
Ideal Behavior ◽  
The Real

AbstractBinary blends of ethanol-diesel, n-butanol-diesel, ethanol-biodiesel, and n-butanol-biodiesel have been analyzed with terahertz time-domain spectroscopy in a full range of concentrations and at room temperature. The real and imaginary parts of the complex dielectric constant of the blends were obtained from the spectra and fitted to the Debye model at low volume concentrations (up to 7.5% for ethanol in diesel and up to 20% for butanol in diesel, ethanol in biodiesel, and butanol in biodiesel blends), considering the number of relaxation processes recommended in the literature for each pure component (single for diesel, double for biodiesel, and triple for alcohols). The results indicate that the faster relaxation time in low alcohol mixtures is longer than in pure alcohols. This relaxation time increases as the alcohol content increases. The excess of the real and of imaginary parts of the dielectric constant were individually determined. The analysis of such excess and of its different contributions (volume, contrast, and interactions) suggests that the intermolecular interactions between the different components of the blends dominate the relaxation dynamics in each pseudo-binary system. Ethanol was found to move blends further away from ideal behavior than n-butanol. In fact, these latter blends showed the most ideal behavior, suggesting that the length of the alcohol carbon chain plays an important role. This information allows a possible link between the nonlinear behavior of the physicochemical properties of the blends (e.g., viscosity and surface tension) and the molecular interactions between their constituent molecules. This relation could have direct application for monitoring the fuel composition and quality in the vehicle control systems.

DIELECTRIC RELAXATION IN CLAYS SATURATED WITH WATER-OIL EMULSION IN A WIDEBAND OF FREQUENCIES AT POSITIVE AND NEGATIVE TEMPERATURES

2021 ◽  
pp. 96-108
Author(s):  
A. V. Repin
Keyword(s):  
Dielectric Constant ◽  
Wide Frequency Range ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Frequency Range ◽  
Water Emulsion ◽  
Oil Emulsion ◽  
Negative Temperatures ◽  
Oil Water ◽  
Account Relaxation

The results of measuring the complex dielectric constant of clays saturated with an oil-water emulsion in various ratios in a wide frequency range are presented. The measurements were used out at positive and negative temperatures. It was revealed that several relaxation processes are observed in the spectra. The processes parameters significantly depend on the temperature and the ratio of water and hydrocarbon to the saturating mixture. A model is proposed that makes it possible to take into account relaxation processes and their dependence on temperature.

High dielectric constants in BaTiO3 doped 90V2O5−10Bi2O3 oxide glasses obeying Debye-type dielectric relaxation behavior

1994 ◽  
Vol 9 (8) ◽  
pp. 1932-1935 ◽  
Author(s):  
Sahana Chakraborty ◽  
A.K. Bera ◽  
S. Mollah ◽  
B.K. Chaudhuri
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Dilution Effect ◽  
Dielectric Behavior ◽  
Dielectric Constants ◽  
Relaxation Behavior ◽  
Oxide Glasses ◽  
Base Glass ◽  
Dielectric Relaxation Behavior ◽  
High Dielectric

BaTiO3 doped 90V2O5−10Bi2O3 (VB) oxide glasses show a larger dielectric constant (102-104) compared to that of the base glass VB (∼102). The VB glass with 15 wt.% BaTiO3 shows the largest dielectric constant, and all the glasses show a Debye-type dielectric relaxation behavior. The increase in dielectric constant appears to be mainly due to the formation of microcrystalline clusters of BaTiO3 (1.8–8 μm, depending on the BaTiO3 concentration present in the base glass). Other than the dilution effect with BaTiO3, the glass-former oxide Bi2O3 also influences the dielectric behavior of BaTiO3 doped VB glasses.

Broadband Dielectric Relaxation of Polymer Composite Films

2000 ◽  
Vol 628 ◽  
Author(s):  
C.K. Chiang ◽  
Roman Popielarz ◽  
Ryusuke Nozaki ◽  
Jan Obrzut
Keyword(s):  
Dielectric Constant ◽  
Relaxation Time ◽  
Composite Materials ◽  
Wireless Communication ◽  
Dielectric Relaxation ◽  
Polymer Composite ◽  
Electronic Devices ◽  
Composite Films ◽  
Dielectric Behavior ◽  
Complex Dielectric Constant

ABSTRACTThe broadband dielectric relaxation of a BaTiO3-polymer composite film was studied. The complex dielectric constant data from 10-4 Hz to 1010 Hz reveals the existence of relaxation process at frequency of 10 MHz in the polymer composite. On the basis of Cole-Cole analysis, the relaxation time of the system is of order of 10-8 s. The understanding of the broad dispersion in dielectric behavior of polymer composite materials is needed to support next generation electronic devices used in wireless communication and related applications.

Dielectric Relaxation Based on Adsorbed Water in Wood Cell Wall under Non-Equilibrium State. Part 3. Desorption

Holzforschung ◽  
2002 ◽  
Vol 56 (6) ◽  
pp. 655-662 ◽  
Author(s):  
C. Jinzhen ◽  
Z. Guangjie
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
Adsorbed Water ◽  
Second Step ◽  
Relaxation Processes ◽  
Relaxation Time Distribution ◽  
Dielectric Parameters ◽  
Frequency Spectra ◽  
Desorption Process ◽  
Content Change

Summary The temperature and frequency spectra of dielectric constant ε′ and dielectric loss factor ε″ of Sikkim spruce (Picea spinulosa Griff.) were measured to investigate the change in dielectric relaxation of water in wood during desorption. In order to control the rate of moisture content change, the measurements were carried out in three steps: from fiber saturation point to 80% RH, from 80% RH to 60% RH and from 60% RH to 20% RH, at 25°C. Two dielectric relaxation processes were observed in different temperature and frequency regions which changed their position and strength with the desorption process. Using the ε′ and ε″ spectra, two groups of Cole-Cole plots were obtained, on which basis two groups of dielectric parameters including the static dielectric constant εS, optic dielectric constant ε∞, relaxation strength (εS–ε∞), and the relaxation time distribution coefficient α were calculated. Both groups of parameters showed similar trends, that is, ε∞ remained nearly constant during the whole desorption process. εS and (εS–ε∞)changed little during the first step of desorption, decreased obviously during the second step and declined slightly during the third step. The α value obtained from the lower frequency data changed significantly during the second and third desorption steps, while there was little change in the other group of α values. These differences can be explained by different mechanisms of the relaxation processes in the lower and higher frequency regions.

Double Dielectric Relaxation of Non-Confocal Membrane-Covered Ellipsoidal Particle Suspensions

1975 ◽  
Vol 30 (12) ◽  
pp. 1675-1679 ◽  
Author(s):  
Hideo Ichimura ◽  
David Feinstein ◽  
Richard F. Schwartz
Keyword(s):  
Dielectric Constant ◽  
Dielectric Relaxation ◽  
The Other ◽  
Complex Dielectric Constant ◽  
Particle Suspensions ◽  
Ellipsoidal Particle ◽  
Shape Factors ◽  
Ellipsoidal Particles

Abstract The complex dielectric constant of suspensions of membrane-covered ellipsoidal particles is formulated in terms of the complex dielectric constant of the interior, the membrane and the medium, the volume ratios p and q, and the shape factors n1 and n2. It is not necessary for the two ellipsoidal interfaces (one between the interior and the membrane, the other between the membrane and the medium) to be confocal, nor for the thickness of the membrane to be uniform. The result is factorized to demonstrate double relaxation.In addition, the blurring mechanism of multiple relaxation is naively explained.

Investigation of Dielectric Properties, Electric Modulus and Conductivity of the Au/Zn-Doped PVA/n-4H-SiC (MPS) Structure Using Impedance Spectroscopy Method

2020 ◽  
Vol 234 (3) ◽  
pp. 505-516 ◽  
Author(s):  
Havva Elif Lapa ◽  
Ali Kökce ◽  
Ahmet Faruk Özdemir ◽  
Şemsettin Altındal
Keyword(s):  
Impedance Spectroscopy ◽  
Electric Modulus ◽  
Forward Bias ◽  
Spectroscopy Method ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Low Frequencies ◽  
High Frequencies ◽  
The Real ◽  
Wide Range

AbstractThe 50 nm thickness Zn-doped polyvinyl alcohol (PVA) was deposited on n-4H-SiC semiconductor as interlayer by electro-spinning method and so Au/Zn-doped PVA/n-4H-SiC metal-polymer-semiconductor (MPS) structure were fabricated. The real and imaginary parts of the complex dielectric constant (ε′, ε′′), loss-tangent (tan δ), the real and imaginary parts of the complex electric modulus (M′, M′′) and ac electrical conductivity (σac) behavior of this structure were examined using impedance spectroscopy method in a wide range of frequency (1 kHz–400 kHz) and voltage (−1 V)–(+6 V) at room temperature. The values of ε′, ε′′, tan δ, M′, M′′ and σac are determined sensitive to the frequency and voltage in depletion and accumulation regions. The values of ε′ and ε′′ decrease with increasing frequency while the values of M′ and σac increase. The peak behavior in the tan δ and M′′ vs. frequency curves was attributed to the dielectric relaxation processes and surface states (Nss). The plots of ln (σac) vs. ln (f) at enough high forward bias voltage (+6 V) have three linear regions with different slopes which correspond to low, intermediate and high frequencies, respectively. The dc conductivity is effective at low frequencies whereas the ac conductivity effective at high frequencies. According to experimental results, the surface/dipole polarizations can occur more easily occur at low frequencies and the majority of Nss between Zn-doped PVA and n-4H-SiC contributes to the deviation of dielectric behavior of this structure.

THE INFLUENCE OF THE SALTITY OF THE MOISTURIZING SOLUTION ON THE DIELECTRIC PERMEABILITY OF CLAYS IN THE FREQUENCY RANGE FROM 1 MHZ TO 8 GHZ

2021 ◽  
pp. 92-101
Author(s):  
A. V. Repin ◽  
O. V. Rodionova
Keyword(s):  
Dielectric Constant ◽  
Salt Solution ◽  
Dielectric Permeability ◽  
Wide Frequency Range ◽  
Complex Dielectric Constant ◽  
Relaxation Processes ◽  
Nacl Solution ◽  
Frequency Range

The article presents the results of measurements of the complex dielectric constant of clays saturated with NaCl solution of various concentrations in a wide frequency range. The measurements were carried out at positive temperatures. It was revealed that several relaxation processes are observed in the spectra. A model is proposed that makes it possible to take into account the relaxation processes and their dependence on the concentration of the salt solution. The concentration practically does not affect the parameters of the processes, in contrast to the temperature.

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