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Modern information technologies has changed our world dramatically during last years. We see how a number of traditional professions were died, and how a number of new specialities and workplaces were born under pressure of new technologies. Technologies are moving so quickly, and in so many directions, that it becomes challenging to even keep in mind a general picture. In this article, we shortly...
The research of electromagnetic response of Ba3Co2Fe24O41 hexaferrite at frequencies 100–975 GHz in temperature range from 296 to 428 K are presented in this paper. At a frequency about ∼ 930 GHz the resonance absorption of electromagnetic wave energy was found. We explain this by the presence of magnetic resonance in materials with helical magnetic ordering.
Possibility of application of ferromagnetic fluids based on semisynthetic oils as medium to control characteristics of terahertz quasioptical beams is shown. Influence of the external magnetic field on the cell with ferrofluid based on magnetite and semisynthetic oils is researched. Coefficients of transmission and permittivity for the plane cell with samples of magnetic fluids in the presence of...
The terahertz dielectric properties of MWCNT/PE composites prepared in different ways and with various contents of carbon nanotubes have been measured by terahertz time-domain spectroscopy. The experimental dielectric susceptibilities were modeled within effective medium approximation.
This paper focuses on the development of the new holographic subsurface radar data acquisition technique in which the position and the polarization of the microwave probe are established by its tracking with video. This technique allows adaptive interactive data acquisition when probe trajectory could not be predefined or be equally dense in the areas with no target. The data processing technique...
In recent years, there has been a surge of new applications of composite materials and structures in aerospace industry. The composites have many advantages over traditional metal alloys. They have, as a rule, better strength/weight ratio, withstand to unfavorable weather conditions and aggressive environments. Corrosion also doesn't affect them. Traditional methods of ultrasonic diagnostics are ineffective...
This paper describes a system for non-destructive testing of radio transparent samples at microwaves. The main components of the system are a vector network analyzer (VNA), one or several stationary antennas connected to it, and a two-coordinate flat mechanical scanner that moves the sample in the antennas vicinity. The VNA and the scanner are controlled by a personal computer, which can acquire the...
Measurements results of spectra of permittivity, permeability, reflection, transmission and absorption coefficients of polymer composite with nanosized filler are presented. Material absorbs electromagnetic waves intensively at superhigh and extremely high frequencies.
A new method for investigation of sensitivity of the integrated optical nonelectrode electric field sensor was designed. This method is based on a compact microwave asymmetrical double-ridged waveguide with regular inhomogenities. Small dimensions of the waveguide along with 1 W power of the microwave generator produce the strong electric field. The sensitivity dielectric sensor electric field strength...
The calculation of the frequency dependence of the permeability tensor components of composite materials containing ferromagnetic magnetouniaxial particles is carried out. The possibility of controlling losses by changing the magnitude of the magnetizing field is also shown.
Using the Smit ??? Suhl method, we have calculated the magnetic susceptibility tensor of magnetized ferromagnetic media with the uniaxial magnetocrystalline anisotropy. An analysis of the obtained formulas in the particular cases of a composite material with randomly oriented ferromagnetic inclusions of ellipsoidal shape has been carried out.
Polystyrene composites with 0.25 wt. % loading of oriented multiwall carbon nanotubes (MWCNTs) have been produced by stretching method. The composites showed anisotropy of transmission of millimeter wave radiation depending on sample orientation relative to the polarization of electromagnetic wave.
Spectra of the complex permittivity of spruce (Picea obovata), obtained by capacitor, resonator and free space techniques in the frequency range 100 kHz ??? 500 GHz are presented. Data from the literature containing information about the permittivity spectra of these wood, are presented. Kramers-Kronig relation can be used to adjust the measurements of the complex permittivity subject to the availability...
Results of measurements of permeability, permittivity and radio absorption properties of composites on basis of R-10 grade carbonyl iron are presented in this paper. Possibility of formation of radio absorption coating with specified reflection coefficient at frequency band least octave is shown for double-layer composite material with different concentration of carbonyl iron in microwave and extremely...
Manual data acquisition with holographic subsurface radar is quite tedious as it requires monotonous scanning with precise positioning at the beginning of each scan line and requirement to move along straight lines to obtain a microwave hologram. A good result with manual scanning requires some practice, which still leaves such difficulties as maintaining constant press to evade image interlace and...
Complex dielectric susceptibilities of MWCNT/PE composites with various contents of nanotubes were measured using THz-TDS and cw THz BWO-spectrometer in the frequency range 100 GHz – 2.2 THz and THz peak powers from microwatts to hundred kilowatts.
At present many countries aimed at development of optoelectronic devices and one of the best looking devices in this area it's a MICROWAVE generator. In this paper we consider the basic principles of construction of generators based on fiber optics. Explore a particular generator design and analyze data for subsequent assembly of the generator running in the microwave range.
At the moment there are many configurations of the integrated optical intensity modulator structures which operate at microwave frequencies (RF). In designing of such devices optical, electrical and electro-optical characteristics should be considered. In this paper, we propose an algorithm of calculation the electro-optical characteristics of the integrated optical modulators, which is compatible...
The electromagnetic response properties of composites with variable loading, containing carbon nanostructures: MWNT and OLC with different mean diameter in PMMA matrix are investigated.
The electromagnetic response properties of PMMA based composites containing multiwalled carbon nanotubes (MWNT) produced using different time of ultrasonic treatment are investigated in the terahertz frequency range.
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