Origin of the abnormal reduction of the dielectric response for ReCOB crystals and its mechanism: theoretical and experimental exploration

2020 ◽  
Vol 8 (29) ◽  
pp. 10109-10120
Author(s):  
Xinyu Lu ◽  
Lili Li ◽  
Shiwei Tian ◽  
Yanlu Li ◽  
Fapeng Yu ◽  
...  
Keyword(s):  
Dielectric Permittivity ◽  
Significant Influence ◽  
Dielectric Response ◽  
Ionic Displacement

The significant influence of ionic displacement polarization on distinct reduction in dielectric permittivity for LaCOB has been confirmed.

Numerical Modeling of Multi-Frequency Complex Dielectric Permittivity Dispersion of Sedimentary Rocks

Geophysics ◽  
2021 ◽  
pp. 1-69
Author(s):  
Artur Posenato Garcia ◽  
Zoya Heidari
Keyword(s):  
Numerical Simulation ◽  
Dielectric Permittivity ◽  
Numerical Simulations ◽  
Dielectric Response ◽  
Water Saturation ◽  
Pore Scale ◽  
Simulation Results ◽  
Wet Rocks ◽  
Permittivity Measurements ◽  
The Impact

The dielectric response of rocks results from electric double layer (EDL), Maxwell-Wagner (MW), and dipolar polarizations. The EDL polarization is a function of solid-fluid interfaces, pore water, and pore geometry. MW and dipolar polarizations are functions of charge accumulation at the interface between materials with contrasting impedances and the volumetric concentration of its constituents, respectively. However, conventional interpretation of dielectric measurements only accounts for volumetric concentrations of rock components and their permittivities, not interfacial properties such as wettability. Numerical simulations of dielectric response of rocks provides an ideal framework to quantify the impact of wettability and water saturation ( Sw) on electric polarization mechanisms. Therefore, in this paper we introduce a numerical simulation method to compute pore-scale dielectric dispersion effects in the interval from 100 Hz to 1 GHz including impacts of pore structure, Sw, and wettability on permittivity measurements. We solve the quasi-electrostatic Maxwell's equations in three-dimensional (3D) pore-scale rock images in the frequency domain using the finite volume method. Then, we verify simulation results for a spherical material by comparing with the corresponding analytical solution. Additionally, we introduce a technique to incorporate α-polarization to the simulation and we verify it by comparing pore-scale simulation results to experimental measurements on a Berea sandstone sample. Finally, we quantify the impact of Sw and wettability on broadband dielectric permittivity measurements through pore-scale numerical simulations. The numerical simulation results show that mixed-wet rocks are more sensitive than water-wet rocks to changes in Sw at sub-MHz frequencies. Furthermore, permittivity and conductivity of mixed-wet rocks have weaker and stronger dispersive behaviors, respectively, when compared to water-wet rocks. Finally, numerical simulations indicate that conductivity of mixed-wet rocks can vary by three orders of magnitude from 100 Hz to 1 GHz. Therefore, Archie’s equation calibrated at the wrong frequency could lead to water saturation errors of 73%.

Measuring Fatigue in PZT Thin Films

1990 ◽  
Vol 200 ◽  
Author(s):  
D. J. Johnson ◽  
D. T. Amm ◽  
E. Griswold ◽  
K. Sreenivas ◽  
G. Yi ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Dielectric Permittivity ◽  
Dielectric Response ◽  
Remanent Polarization ◽  
Small Signal ◽  
Large Signal ◽  
Pzt Thin Films ◽  
Pzt Thin Film

ABSTRACTSmall signal dielectric response is reported for a variety of PZT thin film samples. Small and large signal responses, recorded simultaneously during the fatiguing of PZT thin films, are used to identify distinct fatigue mechanisms. Microcracking or electrode delamination less than 100 Å is sufficient to explain the high correlation between the dielectric permittivity and remanent polarization during fatigue.

High Frequency Dielectric Response of Calcium Aluminate Cements: Potential Packaging Substrate Materials

1987 ◽  
Vol 108 ◽  
Author(s):  
Paul Sliva ◽  
M. Leffler ◽  
M. Bliss ◽  
L. E. Cross ◽  
B. E. Scheetz
Keyword(s):  
Dielectric Permittivity ◽  
Calcium Aluminate ◽  
Dielectric Response ◽  
Room Temperature ◽  
Perturbation Methods ◽  
Microwave Frequency ◽  
Far Infrared ◽  
Poly Vinyl Alcohol ◽  
Relative Dielectric Permittivity ◽  
Dielectric Permittivity And Loss

ABSTRACTDielectric permittivity and loss tangent were measured on: 1) pressed disks of four different calcium aluminate cements shear mixed with water and poly(vinyl alcohol) and cured at room temperature and 2) laminates of SECAR 71 cement sintered at 1450°C. Post resonance and perturbation methods were used for microwave frequency measurements. Far infrared dielectric response of the cements was determined by FTIR in the diffuse reflectance mode. The real and imaginary parts of the relative dielectric permittivity were obtained via a conventional Kramers-Kronig analysis.

scholarly journals A Study on the Dielectric Behaviour of Epoxy/Hafnium Oxide Nanopowder Composites

2011 ◽  
Vol 20 (5) ◽  
pp. 096369351102000 ◽  
Author(s):  
S.N. Georga
Keyword(s):  
Electrical Conductivity ◽  
Dielectric Permittivity ◽  
High Temperatures ◽  
High Frequency ◽  
Dielectric Response ◽  
Hafnium Oxide ◽  
Filler Concentration ◽  
High Frequency Range ◽  
Frequency Range ◽  
Low Frequencies

The dielectric response of 10 and 15phr epoxy/HfO2 nanocomposite systems has been studied in a wide frequency and temperature range. The experimental results show an enhancement of the dielectric permittivity with increasing filler concentration. The dielectric spectra reveal the presence of α-relaxation and a weak MWS effect. In the high frequency range the real part of the electrical conductivity obeys the Universal Dielectric Response (UDR), whereas at low frequencies and high temperatures DC conductivity is observed. VFT (Vogel-Fulcher-Tamann) parameters are calculated for all measured specimens.

Analysis of the complex dielectric permittivity behavior of porous Al2O3–SiC composites in the 1 MHz to 18 GHz frequency range

2007 ◽  
Vol 22 (12) ◽  
pp. 3292-3302 ◽  
Author(s):  
J. Battat ◽  
J.P. Calame
Keyword(s):  
Dielectric Permittivity ◽  
Dielectric Response ◽  
Porous Alumina ◽  
Complex Dielectric Permittivity ◽  
Polymer Precursor ◽  
Frequency Range ◽  
Subsequent Step ◽  
Infusion Method ◽  
Sic Composites ◽  
Scanning Electron

The complex dielectric permittivity of electrically lossy, porous Al2O3–SiC composites was measured as a function of frequency over the range of 0.001 to 18 GHz. These composites were fabricated by an infusion method of incorporating SiC polymer precursor into porous alumina disks. Repeat polymer infusions and pyrolysis steps to 1000 °C were carried out, with some samples undergoing an additional air fire prior to each subsequent step. Generally, it was found that for non-air-fired samples, moderate, controllable losses were attainable over a broad frequency range. By contrast, the dielectric loss attainable for air-fired samples was generally very low. For all samples, various aspects of the variation of permittivity components ϵ′ and ϵ″ with frequency were analyzed, with a view to determine the various factors contributing to dielectric response. Microstructure analysis using scanning electron microscopy was also performed.

CONTRIBUTION OF THE INTERPHASE INTERACTION TO THE DIELECTRIC PERMITTIVITY OF COLLOID SYSTEMS

2011 ◽  
Vol 01 (02) ◽  
pp. 169-178
Author(s):  
V. S. BORISOV
Keyword(s):  
Dielectric Permittivity ◽  
Dielectric Response ◽  
Solid Particles ◽  
Polar Liquid ◽  
Surface Charges ◽  
Interphase Interaction ◽  
Colloid System ◽  
Wide Range ◽  
Two Phases ◽  
Colloid Systems

Specific features of the dielectric response of colloid systems with electrically interacting components (polar liquid matrix and solid spherical inclusions) have been revealed. A theory was developed to describe dielectric dispersion and anisotropy of the liquid phase caused by the electric field of surface charges on the solid particles. It was found that the local dielectric permittivity in different directions can vary over a wide range and strongly depends on the strength of the inner field. The existence of the interphase interaction leads to the formation of thin structured liquid layers in the contact area of two phases and, therefore, to a decrease in the average dielectric permittivity of the considered system. Nonuniform structure of the polar liquid was taken into account while the derivation of a mixing formula which clearly demonstrates the contribution of the interphase interaction to the dielectric response of the investigated colloid system.

Broadband electrical properties of clays and shales: Comparative investigations of remolded and preserved samples

Geophysics ◽  
2015 ◽  
Vol 80 (2) ◽  
pp. D129-D143 ◽  
Author(s):  
Matthew Josh ◽  
Ben Clennell
Keyword(s):  
Dielectric Permittivity ◽  
Dielectric Response ◽  
Gamma Ray ◽  
Clay Content ◽  
Exchange Capacity ◽  
Drill Cuttings ◽  
Mixing Ratios ◽  
Swelling Clays ◽  
Drill Cutting

The dielectric permittivity of mudrocks cannot be determined from the mixing ratios of the constituent minerals and brine and their individual dielectric response. The high-frequency dielectric permittivity is linked ([Formula: see text] correlation) to water content, but the relationship is complicated by mineral type and the hydration state. The cation exchange capacity (CEC) and specific surface area (SSA) determine the establishment of a polarizable electrical double layer and give rise to the long range diffusion of ions leading to Maxwell-Wagner polarization. This ultimately determines the dielectric response below 50 MHz. Procedures for SSA analysis based on sorption of 2-ethoxyethanol and CEC analysis based on methylene blue titration, were developed for investigating swelling clays. These were combined with a procedure for preparing remolded paste samples from pulverized rock and drill cuttings to form the basis of this investigation. In a case study of 123 drill cutting samples retrieved from an undisclosed well, dielectric analysis of the remolded samples exhibits [Formula: see text] correlation with SSA, [Formula: see text] correlation with CEC, and [Formula: see text] correlation with clay content. A pseudodielectric log of the remolded drill cuttings exhibited a weak correlation with downhole resistivity, gamma ray, and compressional slowness logs measured by a service company in the shaly sections of the well, but no correlation in the sandy section of the well. This attributed to better preservation of shaly cuttings due to finer microstructure and therefore less alteration during uphole transport and sample preparation.

scholarly journals The effect of an AC electric field on the dielectric properties of Pb(Mg1/3Nb2/3)O3 ceramic

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
E.C. Lima ◽  
J.D.S. Guerra ◽  
E.B. Araujo
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Electric Field ◽  
Statistical Model ◽  
Dielectric Response ◽  
Freezing Temperature ◽  
Dielectric Dispersion ◽  
Electrical Field ◽  
Ac Electric Field ◽  
Applied Electrical Field

The dynamic dielectric response of Pb(Mg1/3Nb2/3 )O3 ceramic was experimentally studied as a function of the EAC amplitude field. An increase in real dielectric permittivity was obtained by increasing the applied electrical field within the investigated temperature range for frequencies below 10 kHz. The temperature of maximum dielectric permittivity and freezing temperature decreased with an increase in E AC. Nonlinear permittivity was studied and found to behave similarly to freezing temperature. A statistical model was used to fit the dielectric dispersion of real dielectric permittivity with temperature and frequency. The results are discussed in terms of different factors’ contributions to dielectric permittivity under different EAC field conditions.

scholarly journals Experimental Characterization of Dielectric Properties in Fluid Saturated Artificial Shales

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Roman Beloborodov ◽  
Marina Pervukhina ◽  
Tongcheng Han ◽  
Matthew Josh
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Dielectric Response ◽  
Pore Space ◽  
Mineralogical Composition ◽  
Data Interpretation ◽  
Dielectric Anisotropy ◽  
Geomechanical Properties ◽  
High Dielectric ◽  
Rock Microstructure

High dielectric contrast between water and hydrocarbons provides a useful method for distinguishing between producible layers of reservoir rocks and surrounding media. Dielectric response at high frequencies is related to the moisture content of rocks. Correlations between the dielectric permittivity and specific surface area can be used for the estimation of elastic and geomechanical properties of rocks. Knowledge of dielectric loss-factor and relaxation frequency in shales is critical for the design of techniques for effective hydrocarbon extraction and production from unconventional reservoirs. Although applicability of dielectric measurements is intriguing, the data interpretation is very challenging due to many factors influencing the dielectric response. For instance, dielectric permittivity is determined by mineralogical composition of solid fraction, volumetric content and composition of saturating fluid, rock microstructure and geometrical features of its solid components and pore space, temperature, and pressure. In this experimental study, we investigate the frequency dependent dielectric properties of artificial shale rocks prepared from silt-clay mixtures via mechanical compaction. Samples are prepared with various clay contents and pore fluids of different salinity and cation compositions. Measurements of dielectric properties are conducted in two orientations to investigate the dielectric anisotropy as the samples acquire strongly oriented microstructures during the compaction process.

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