ChemInform Abstract: DIELECTRIC PROPERTIES OF CALCIUM FLUORIDE SINGLE CRYSTALS IN THE ULTRA LOW FREQUENCY RANGE

1979 ◽  
Vol 10 (30) ◽  
Author(s):  
R. MADRU ◽  
M. MAITROT
Keyword(s):  
Dielectric Properties ◽  
Single Crystals ◽  
Calcium Fluoride ◽  
Low Frequency ◽  
Frequency Range

Single Crystals of Ice Grown from KCl Solution and Their Dielectric Properties

1973 ◽  
Vol 51 (10) ◽  
pp. 1045-1052 ◽  
Author(s):  
Norikazu Maeno
Keyword(s):  
Activation Energy ◽  
Dielectric Properties ◽  
Crystal Lattice ◽  
Single Crystals ◽  
Low Frequency ◽  
Distribution Coefficients ◽  
Square Root ◽  
Dielectric Polarization ◽  
Kcal Mole ◽  
Upper Limit

Single crystals of ice were grown from KCl solution and their dielectric properties were investigated as functions of concentration, frequency, and temperature. It was found that a limited amount of chlorine was incorporated into the crystal lattice of ice but no trace of potassium. The upper limit of the substitutional incorporation of chlorine was approximately 1 × 10−4M(g moles/1). The distribution coefficients of the solutes were obtained as functions of the KCl concentration of the mother solution.The static dielectric constant of the single crystals of ice decreased due to the chlorine incorporation and the activation energy of its dielectric relaxation was reduced to 5.8 kcal/mole. The low-frequency conductivity increased with the square root dependence upon the chlorine concentration, and its activation energy was 6.1 kcal/mole. The mechanism of the dielectric polarization and conduction was discussed in relation to the defects introduced by chlorine built in the crystal lattice.

scholarly journals Dielectric Properties of Ternary ( ) ( )x ( ) x ZnO MgO PO 30 2 5 70− (x = 5, 8, 13) Glasses

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
S. F. Khor ◽  
Z. A. Talib ◽  
W. M. Daud ◽  
H. A. A. Sidek ◽  
W. M. M. Yunus ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Empirical Data ◽  
Loss Factor ◽  
Low Frequency ◽  
Frequency Range ◽  
Melt Quenching ◽  
Dipolar Relaxation ◽  
Temperature Range

(ZnO)30(MgO)x(P2O5)70-x glasses of the composition x = 5, 8 and 13 mol % have been prepared by melt quenching technique. The dielectric permittivity (89) and loss factor (8:) were measured in the frequency range from 0.01 Hz to 1 MHz and in the temperature range 303 to 573 K . From the results there are evidence of dipolar relaxation occurring between 103 – 106 Hz while at low frequency the spectrum is dominated by dc conduction which manifested by the 1/@ slope of loss factor plot. Value of the relaxing frequency (@p) plotted against 1/T shows one electrical transportation mechanism. The empirical data was sufficiently fitted by using Harviliak-Negami equation.

scholarly journals Estimation of Dielectric Properties of Clay Loam and Silty Soil With Different Salinity Levels Over Low Frequency Range

2021 ◽  
Vol 120 (2) ◽  
pp. 414
Author(s):  
Virendrakumar N. Patel ◽  
Prahalad D. Chaudhary ◽  
Vipin A. Rana ◽  
Deepak H. Gadani
Keyword(s):  
Dielectric Properties ◽  
Low Frequency ◽  
Clay Loam ◽  
Frequency Range ◽  
Silty Soil ◽  
Salinity Levels

Investigation of dielectric behavior of water and thermally aged of XLPE/BaTiO3 composites in the low-frequency range

2015 ◽  
Vol 29 (27) ◽  
pp. 1550186 ◽  
Author(s):  
Lakhdar Madani ◽  
Saad Belkhiat ◽  
Amine Berrag ◽  
Saad Nemdili
Keyword(s):  
Dielectric Properties ◽  
Thermal Aging ◽  
Low Frequency ◽  
Dielectric Behavior ◽  
Response Analysis ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Two Samples ◽  
Measured Frequency Response ◽  
Loss Index

Cross-Linked Polyethylene (XLPE) is widely used as insulation in electrical engineering, especially as cable insulation sheaths. In order to improve the dielectric properties susceptible to be modified under the effects of thermal aging and water in an absorption environment, polymers are mixed with ceramics. In this paper, the influence of barium titanate (BaTiO3), on the dielectric properties of XLPE has been studied. Dielectric parameters have been measured using an impedance analyzer RLC (WAYNE KERR 6420 type). Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy and X-ray diffraction were used as characterization techniques. The study has been carried out on two samples of XLPE. A pure sample of each were studied as a unloaded samples to be compared with samples of 5%wt, 10%wt, 15%wt and 20%wt. BaTiO3 loaded XLPE. Afterwards, the composites were subject to humidity and to thermal aging. The incorporation of BaTiO3 1[Formula: see text]C does not modify the crystallinity and morphology of the XLPE and 2[Formula: see text]C reduces the space charges therefore the dielectric losses. [Formula: see text], [Formula: see text] and loss index are measured. Frequency response analysis has been followed in the frequency range (20–300 Hz). Experimental results show well that BaTiO3 as nano-filler improves the dielectric properties of XLPE but in excessive content can drive to the cracking and therefore to absorption of water.

scholarly journals Influence of Radiation on the Dielectric Properties of XLPE Based Insulation Systems

2010 ◽  
Vol 61 (4) ◽  
pp. 229-234 ◽  
Author(s):  
Vladimír Ďurman ◽  
Jaroslav Lelák
Keyword(s):  
Dielectric Properties ◽  
Structural Changes ◽  
Low Frequency ◽  
Absorbed Dose ◽  
Frequency Range ◽  
Impedance Measurements ◽  
Motion Data ◽  
Dielectric Data ◽  
Insulation Systems ◽  
The Cross

Influence of Radiation on the Dielectric Properties of XLPE Based Insulation SystemsThe paper discusses the possibilities of acquiring and processing the dielectric data in the range of very low frequency (VLF) and also design and construction of an impedance analyzer for measurements in this frequency range. The impedance measurements in the VLF range were used for investigation of the influence of radiation on the cross-linked polyethylene cable dielectric. An expressive β-type relaxation process was found in this type of cable. Most of the dielectric response parameters of the process depend significantly on the absorbed dose of radiation. The analysis of the process parameters showed that the most probable reason of the structural changes in cross-linked polyethylene was additional cross-linking. The results also proved that the impedance measurements in the VLF range could be effectively used in practice for estimation of the absorbed dose in the cross-linked polyethylene cables stressed by radiation.t data only. In order to identify or classify motion, data processing in real time is needed.

scholarly journals Исследование влияния постоянного электрического поля на диэлектрические свойства LiNbO-=SUB=-3-=/SUB=-

2020 ◽  
Vol 90 (4) ◽  
pp. 647
Author(s):  
А.В. Яценко ◽  
С.М. Кострицкий
Keyword(s):  
Dielectric Properties ◽  
Field Strength ◽  
Electric Field ◽  
Strong Electric Field ◽  
Low Frequency ◽  
Polar Axis ◽  
Frequency Region ◽  
Frequency Range ◽  
Static Electric Field

The effect of a strong electric field on the dielectric properties of nominally pure LiNbO3 crystals of congruent composition in the low-frequency region is experimentally investigated. It is shown that an external static electric field, directed along or antiparallel to the polar axis of the crystal, as well as a field of pyroelectric nature at a field strength of up to 14 kV / cm within the error does not affect the dielectric properties of the crystal in the low frequency range.

scholarly journals Inelastic Behaviour of Ice Ih Single Crystals in the Low-Frequency Range Due to Dislocations

1978 ◽  
Vol 21 (85) ◽  
pp. 375-384 ◽  
Author(s):  
René Vassoille ◽  
Christian Maï ◽  
Joseph Perez
Keyword(s):  
High Temperature ◽  
Internal Friction ◽  
Single Crystals ◽  
Empirical Relation ◽  
Low Frequency ◽  
Frequency Range ◽  
High Temperature Range ◽  
Temperature Range ◽  
Inelastic Behaviour ◽  
Torsional Pendulum

Abstract The inelastic behaviour of ice Ih single crystals has been investigated by an inverted torsional pendulum in the low-frequency range. Three features are distinguished: (i) a relaxation peak previously observed by several authors in the higher-frequency range, (ii) an internal friction increasing with temperature in the high-temperature range (230–273 K), (iii) within this high-temperature range, internal friction becomes amplitude dependent, and this dependence becomes greater the greater the temperature. In this case, the internal friction has been interpreted in terms of movements of dislocations. Hence, the experimental results are interpreted with a model of internal friction based on an empirical relation for the velocity of dislocations. This model of internal friction is in fair agreement with experimental data . It is possible then to get an estimate of dislocation density. Hence it is shown that internal friction experiments can be useful in the study of the plastic behaviour of ice single crystals.

scholarly journals Влияние тока, ограниченного объемным зарядом, на диэлектрические свойства поликристаллических пленок фуллерита С-=SUB=-60-=/SUB=-

2021 ◽  
Vol 91 (1) ◽  
pp. 58
Author(s):  
Д.И. Долженко ◽  
В.Ф. Бородзюля ◽  
И.Б. Захарова ◽  
Н.Т. Сударь
Keyword(s):  
Dielectric Properties ◽  
Electric Fields ◽  
High Frequency ◽  
Low Frequency ◽  
Negative Polarity ◽  
Frequency Range ◽  
Anomalous Increase ◽  
Electrical Capacity ◽  
P Type

In the frequency range from 30 Hz to 1 MHz, the dielectric properties of polycrystalline fullerite films with a thickness of about 300 nm, which are part of p-type Si / C60 / InGa structures, were studied under the influence of constant electric fields with a strength of up to 33 MV / m. It was found that at negative polarity of the InGa electrode, when the injection of electrons from the metal into the fullerite is facilitated, at frequencies less than 1000 Hz, an anomalous increase in the electrical capacity of the sample is observed, while the capacitance at a low frequency exceeds the capacitance at a high frequency by more than 1000 times. An explanation for this effect is proposed.

Sign in / Sign up

Export Citation Format

Share Document