scholarly journals Поглощение энергии в композиции диэлектрик--дисперсный проводник в зависимости от частоты сигнала

2020 ◽  
Vol 90 (6) ◽  
pp. 976
Author(s):  
В.А. Соцков ◽  
О.Г. Ашхотов ◽  
Т.Т. Магкоев
Keyword(s):  
Magnetic Material ◽  
Frequency Dependence ◽  
Applied Voltage ◽  
Skin Effect ◽  
Active Resistance

The dependences of the active resistance of a number of dielectric-conductor composites on the frequency of the applied voltage in the range of less than one megahertz are experimentally investigated. It is shown that the frequency dependence of the active resistance in dielectric-conductor composites with non-magnetic material is small and is limited by the effect of the skin effect, and in composites with ferromagnetic resistivity decreases by one or two orders of magnitude with increasing frequency.

Analysis of Exact and Approximating Dependences of the Active Resistance of Conductor on the Frequency of Current Under the Action of Skin Effect

2021 ◽  
Author(s):  
Yakiv Scherbak ◽  
Oleksandr Plakhtii ◽  
Volodymyr Nerubatskyi ◽  
Denys Hordiienko ◽  
Dmytro Shelest ◽  
...  
Keyword(s):  
Skin Effect ◽  
Active Resistance

AC magnetoresistance and its frequency-dependence of Fe-doped Bi2Se3 topological insulator

2020 ◽  
Vol 34 (26) ◽  
pp. 2050276
Author(s):  
Qiya Liu ◽  
Ke Zhao ◽  
Xinsheng Yang ◽  
Yong Zhao
Keyword(s):  
Magnetic Field ◽  
Frequency Dependence ◽  
Topological Insulator ◽  
Magnetic Order ◽  
Skin Effect ◽  
Direct Method ◽  
Relaxation Mechanism ◽  
Current Frequency ◽  
Base Materials ◽  
A Direct Method

Bismuth selenide (Bi2Se3) is one of the most important base materials in the study of topological insulators. Doping with iron is a direct method to manipulate the magnetic order in Bi2Se3. In this paper, we first report the measurements of magnetoresistance of Fe-doped Bi2Se3 with alternating current. Unlike the DC magnetoresistance, skin effect plays an important role in AC magnetoresistance. Another interesting finding is that resonance occurs at a certain frequency, which implies an internal relaxation mechanism. The relations between resistance, magnetic field and current frequency are discussed.

Analysis of the Resistances of the Equivalent Circuit of TM Series Transformers

2021 ◽  
Vol 64 (1) ◽  
pp. 43-47
Author(s):  
Sergey Plotnikov ◽  
Keyword(s):  
Equivalent Circuit ◽  
Skin Effect ◽  
Reference Data ◽  
Active Resistance ◽  
Secondary Resistance ◽  
Thermal Change ◽  
Electrical Skin

An assessment of the ratio of active and reactive components of the resistances of the primary and secondary windings of transformers included in the simplified equivalent circuit is made. It is shown that the reactances of the primary and reduced secondary windings are the same. Based on the reference data of the TM series transformers, it has been established that the active resistance of the primary winding exceeds the reduced secondary resistance. The ratios of the resistances of the primary and reduced secondary windings of transformers with a capacity of 20 to 1000 kVA are obtained, taking into account the electrical skin effect and thermal change in the resistances of copper and aluminum windings

scholarly journals Analysis of exact and approximating dependences of active resistance of a conductor on the current frequency based on the influence of skin effect

2021 ◽  
pp. 99-112
Author(s):  
Volodymyr Pavlovych Nerubatskyi ◽  
Alexandr Andreevych Plakhtii ◽  
Denys Anatolievych Hordiienko ◽  
Hryhorii Anatolievych Khoruzhevskyi ◽  
Marina Vitalievna Philipjeva
Keyword(s):  
Skin Effect ◽  
Electrical Networks ◽  
Power Losses ◽  
Nonlinear Loads ◽  
Active Resistance ◽  
Higher Harmonics ◽  
Current Frequency ◽  
Negative Effect ◽  
Compensating Devices ◽  
Analytical Expressions

The operation of semiconductor power converters, which are part of tractionsubstations, frequency-controlled electric drives and other powerful nonlinear loads, cause asignificant emission of higher harmonics of currents to electrical networks. Higher harmonics ofcurrents in electrical networks cause a complex negative effect on the energy efficiency of thenetwork. The increase in power losses in the active resistance under the action of higher harmonicsis due to the increase in the root mean square value of the current and the action of the skin effect.Analytical expressions describing the dependence of the active and impedance of the electricnetwork on the current frequency are determined. Based on them, analytical expressions are obtainedfor the calculation of additional power losses under the action of higher harmonics of currents, whichare due to the skin effect. The dependences of the active resistance of the electric network on thefrequency of higher harmonics are determined on the basis of Bessel equations. The analysis of convergence of the received equations with the data of the international standard IEC 60287-1-1 iscarried out. For the high-frequency zone, simplified approximating dependences are given, whichdetermine the parabolic dependence of the active resistance on the frequency. Simplifiedapproximating dependences of active resistance on the frequency of higher harmonics are obtainedfor engineering calculations. The obtained equations can be used to determine additional powerlosses in the active supports of electrical networks, windings of electric machines, high-frequencytransformers from higher harmonics of currents at different nonlinear loads. In addition, the obtainedexpressions can be used to justify the use of filter-compensating devices.

scholarly journals The influence of fractal geometry on anomalous skin-effect in metal systems

2019 ◽  
Vol 30 ◽  
pp. 07016 ◽  
Author(s):  
Nikolay Torkhov ◽  
Leonid Babak ◽  
Audrey Kokolov ◽  
Feodor Sheyerman
Keyword(s):  
Transmission Lines ◽  
Fractal Geometry ◽  
Skin Effect ◽  
Local Approximation ◽  
Skin Layer ◽  
Active Resistance ◽  
Surface Fractal ◽  
Microwave Transmission ◽  
Anomalous Skin Effect

The paper defines basic criteria of surface fractal geometry for 50Ω Au/i-GaAs{100} coplanar microwave transmission lines, which influence on active resistance of their skin-layer and inductivity L. The local approximation limit L for active resistance L(R) is ≈800 um and for inductivity L(L) is ≈400 um.

scholarly journals Frequency Dependence of Electroluminescence Measurement in LDPE

2017 ◽  
Vol 7 (3) ◽  
pp. 1406
Author(s):  
Nurul Aini Bani ◽  
Zulkurnain Abdul-Malek ◽  
Siti Armiza Mohd Aris ◽  
Siti Zura A. Jalil ◽  
Mohd Nabil Muhtazaruddin ◽  
...  
Keyword(s):  
Dielectric Loss ◽  
Frequency Dependence ◽  
High Voltage ◽  
Applied Voltage ◽  
External Factors ◽  
Applied Frequency ◽  
Low Dielectric ◽  
Electrical Degradation ◽  
Electroluminescence Emission

A good insulator for high voltage cable has low dielectric loss, reasonable flexibility and thermo-mechanically stable. However, prolonged application of electrical stresses on the cable will degraded the cable; physically and morphologically. Electrical degradation in high voltage cable can be detected using electroluminescence (EL) method. Electroluminescence is a phenomenon that occurs when the atoms of a material are being excited due to the application of and external high electrical stresses. There are several external factors that affect the behaviour of electroluminescence emission such as, applied voltage, applied frequency, ageing of material and types of materials. . In this paper, the EL measurement is employed to determine the effect of applied frequency on virgin LDPE at fixed and varying applied voltage. It can be observed that EL emission increases as applied frequency increases with increasing voltage applied. However, interesting EL behaviour is observed when varying frequency is applied from 10 Hz to 100 Hz.

Magnetic Material Observation Assembly for Tem with a Eucentric Goniometer

1976 ◽  
Vol 34 ◽  
pp. 540-541
Author(s):  
K. Shi rota ◽  
A. Yonezawa ◽  
K. Shibatomi ◽  
T. Yanaka
Keyword(s):  
Magnetic Material ◽  
Electron Microscope ◽  
Magnetic Domain ◽  
Objective Lens ◽  
Magnetic Domains ◽  
Lorentz Microscopy ◽  
Transmission Electron ◽  
Correction Of Astigmatism ◽  
Single Orientation ◽  
Conventional Transmission Electron Microscope

As is well known, it is not so easy to operate a conventional transmission electron microscope for observation of magnetic materials. The reason is that the instrument requires re-alignment of the axis and re-correction of astigmatism after each specimen shift, as the lens field is greatly disturbed by the specimen. With a conventional electron microscope, furthermore, it is impossible to observe magnetic domains, because the specimen is magnetized to single orientation by the lens field. The above mentioned facts are due to the specimen usually being in the lens field. Thus, special techniques or systems are usually required for magnetic material observation (especially magnetic domain observation), for example, the technique to switch off the objective lens current and Lorentz microscopy. But these cannot give high image quality and wide magnification range, and furthermore Lorentz microscopy is very complicated.

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