scholarly journals Диэлектрическая спектроскопия пленок VO-=SUB=-2-=/SUB=-:Ge

2019 ◽  
Vol 45 (11) ◽  
pp. 44
Author(s):  
А.В. Ильинский ◽  
Р.А. Кастро ◽  
А.А. Кононов ◽  
М.Э. Пашкевич ◽  
И.О. Попова ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Complex Impedance ◽  
High Sensitivity ◽  
Circuit Diagram ◽  
Frequency Range ◽  
Cole Diagram ◽  
Additional Maximum

AbstractThe frequency dependencies of complex impedance $$\dot {Z}$$ , dielectric permittivity ε, and dielectric loss tangent tanδ of thin (1400 Å ) films V_1 –_ x Ge_ x O_2 (for x = 0 and 0.03) are studied in the frequency range of 10‒10^6 Hz at 300 K. It is found that, at x = 0, the frequency dependence of tanδ has a maximum at a frequency of 100 kHz, whereas at x = 0.03 an additional maximum in the region of 10 kHz is detected. Also, the Cole–Cole diagram of VO_2:Ge films acquires a feature in the form of an additional semicircle. Owing to the extremely high sensitivity of the dielectric spectroscopy method, the proposed equivalent circuit diagram of the sample allowed detecting the existence of two sets of VO_2 nanocrystallites in the V_0.97Ge_0.03O_2 film, including Ge-doped nanocrystallites and practically nondoped ones.

An Investigation of the Effect of Laser Radiation on the Dielectric Parameters of Polymethyl Methacrylate

2018 ◽  
Vol 45 (5) ◽  
pp. 205-207
Author(s):  
Z.S. Torshkhoeva ◽  
A.S. Akhriev ◽  
B.I. Kunizhev
Keyword(s):  
Laser Radiation ◽  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Laser Pulse ◽  
Polymethyl Methacrylate ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Pulse Treatment ◽  
Dielectric Parameters ◽  
Temperature Range

The effect of laser radiation on the dielectric parameters of polymethyl methacrylate at a frequency of 50 kHz in the 170–420 K temperature range was investigated. It was shown that the laser pulse treatment of specimens leads to considerable changes in their dielectric permittivity and dielectric loss tangent.

scholarly journals Analysis of the temperature-frequency effect on dielectric losses in a grain medium

2022 ◽  
Vol 25 (6) ◽  
pp. 733-740
Author(s):  
M. Yu. Buzunova
Keyword(s):  
Dielectric Loss ◽  
Electric Field ◽  
Mechanical Activation ◽  
External Electric Field ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Dielectric Losses ◽  
Frequency Range ◽  
Dielectric Parameters ◽  
Dielectric Characteristics

The aim of the study is to determine the influence of the thermal effect on dielectric losses in grain mass subject to bruising during drying and storage on the example of wheat across a wide external electric field frequency range. The study of the electrophysical characteristics of a dispersed medium comprising mechanically activated wheat grains takes into account the effect of the degree of breakage on the dielectric parameters of the studied medium. The studies were carried out on experimental samples having different degrees of mechanical activation of particles, which ranged in size from from 50 to 1000 μm. Variations in the dielectric loss tangent were studied using the dielectric method across a wide temperature-frequency range. Studies of variations in dielectric properties were carried out for wheat sam-ples subjected to grinding according to the mechanical activation method at temperatures varying from 20°C to 255°C with a constant heating rate of 0.7 deg / min. During the course of the experiment, the frequency of the external electric field was varied from 25 Hz to 1∙106 Hz. Dielectric constant and dielectric loss tangent calculations were carried out using data on electrical capacity and conductivity obtained using an E7-20 immittance meter and a measuring cell in the form of a flat capacitor. An analysis of variations in these dielectric characteristics was also performed. The obtained stable correlation of the dielectric loss tangent with the frequency of external electric impact and the degree of heating of the samples was most pronounced for finely dispersed samples (particle size 50 μm). Variations in dielectric characteristics are most significant when the frequency decreases to 100 Hz and below. The study of variations in the main dielectric parameters can be used to prevent self-heating and ignition of the grain mass during storage, as well as for selecting the most efficient energy-saving drying mode.

Electrophysical properties of mixtures of mineral oil and synthetic ester dielectric liquid

2021 ◽  
Vol 14 (2) ◽  
pp. 132-141
Author(s):  
M. N. Lyutikova ◽  
S. M. Korobeynikov ◽  
A. A. Konovalov
Keyword(s):  
Dielectric Loss ◽  
Breakdown Voltage ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Kinematic Viscosity ◽  
Mineral Oil ◽  
Flash Point ◽  
Power Transformers ◽  
Synthetic Ester ◽  
Insulating Properties

Power transformers are key equipment in power generation, transmission, and distribution systems. The reliability of power transformers is based on the performance of the insulation system, which includes solid cellulose insulation and a liquid dielectric. Modern power engineering requires liquid insulation to have excellent insulating properties, high fire resistance, and biodegradability. Mineral oil that has been in use for over 100 years does not meet certain requirements. Therefore, various methods of enhancing the insulating properties of the oil are currently being considered, including mixing it with other liquid dielectrics, which have excellent properties. Synthetic and natural esters are considered as alternative fluids.This article discusses the possibility of enhancing the insulating characteristics of mineral oil with a high content of aromatic hydrocarbons (for example, T-750 oil) by mixing it with synthetic ester Midel 7131. Assessment is given of insulating parameters of the resulting mixtures with an ester fraction in mineral oil from 0% to fifty%. The main characteristics of the mixtures are described, such as density, kinematic viscosity, flash point, dielectric loss tangent, relative dielectric permittivity, breakdown voltage, and moisture content. It is shown that with an increase in the proportion of ester, some parameters of the obtained insulating liquid improve (flash point, dielectric constant, breakdown voltage), while values of other parameters (density, kinematic viscosity, dielectric loss tangent) with an ester content of more than 10% in the mixture do not meet the requirements for mineral oils.

Method of calculating the dielectric loss tangent of binary systems

1987 ◽  
Vol 52 (3) ◽  
pp. 310-312
Author(s):  
G. N. Dul'nev ◽  
D. P. Volkov ◽  
M. V. Dobrochasov
Keyword(s):  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Binary Systems

scholarly journals Смена знака магнитоемкости в парамагнитной области в катион-замещенном селениде марганца

2018 ◽  
Vol 60 (4) ◽  
pp. 670
Author(s):  
С.С. Аплеснин ◽  
М.Н. Ситников ◽  
А.М. Живулько
Keyword(s):  
Magnetic Field ◽  
Solid Solution ◽  
Magnetic Susceptibility ◽  
Dielectric Loss ◽  
Dielectric Permittivity ◽  
Room Temperature ◽  
Frequency Range ◽  
Wagner Model ◽  
Paramagnetic Region ◽  
Orbital Electron

AbstractThe capacity and the dielectric loss tangent of a Gd_ x Mn_1– x Se ( x ≤ 0.2) solid solution have been measured in the frequency range 1–300 kHz without a magnetic field and in a magnetic field of 8 kOe in the temperature range 100–450 K, and the magnetic moment of the solid solution has been measured in a field of 8.6 kOe. The magnetocapacity effect and the change in the magnetocapacity sign have been observed in room temperature in the paramagnetic region. A correlation of the changes in the dielectric permittivity and the magnetic susceptibility with temperature has been revealed. The magnetocapacity is described using the model with orbital electron ordering and the Maxwell–Wagner model.

scholarly journals Dielectric and electrical properties of Cr substituted Mg ferrites

2015 ◽  
Vol 39 (1) ◽  
pp. 1-12 ◽  
Author(s):  
AKM Zakaria ◽  
Faizun Nesa ◽  
MA Saeed Khan ◽  
SM Yunus ◽  
NI Khan ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Lattice Parameter ◽  
Activation Energies ◽  
X Ray Diffraction ◽  
Constant E ◽  
Cr Concentration ◽  
Academy Of Sciences

The spinel ferrites MgCrxFe2-xO4 (0.0 ? × ?1.0) were prepared through the solid state reaction using conventional ceramic method at 1300°C in air. The homogeneous phase of the ferrite samples was observed from the X-ray diffraction study. Lattice parameter of the samples was found to decrease with increasing Cr concentration in the system obeying Vegard’s law. The ac electrical resistivity, measured as a function of temperature, decreases with the increase of temperature indicating the semiconducting nature of all the samples. The activation energies were calculated and found to decrease with increasing Cr content. The lower activation energies are associated with higher electrical conductivity. With the increase of temperature, dielectric constant (e`) and dielectric loss tangent are observed to be increased; while with the increase of frequency, dielectric constant (e`) and dielectric loss tangent decrease for all the samples.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 1-12, 2015

Multipurpose Nonwoven Viscose/Polypropylene Fabrics: Effect of Fabric Characteristics and Humidity Conditions on the Volume Electrical Resistivity and Dielectric Loss Tangent

2020 ◽  
Vol 21 (10) ◽  
pp. 2407-2416
Author(s):  
Koviljka A. Asanovic ◽  
Dragana D. Cerovic ◽  
Mirjana M. Kostic ◽  
Tatjana V. Mihailovic ◽  
Aleksandra M. Ivanovska
Keyword(s):  
Electrical Resistivity ◽  
Dielectric Loss ◽  
Loss Tangent ◽  
Dielectric Loss Tangent

scholarly journals In-situ measurement of electric current and dielectric loss tangent during vulcanisation of nitrile rubber.

1998 ◽  
Vol 71 (5) ◽  
pp. 281-285 ◽  
Author(s):  
Toyohiko GONDOH ◽  
Yukiko MATSUOKA ◽  
Michiharu TOH ◽  
Daisaburo OKAI ◽  
Tetsuo MORI
Keyword(s):  
Dielectric Loss ◽  
Electric Current ◽  
Loss Tangent ◽  
Dielectric Loss Tangent ◽  
Nitrile Rubber ◽  
In Situ Measurement
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