The paper presents the results of a theoretical study of the dispersion characteristics of electromagnetic waves (EMW) existing in a transversely magnetized antiferromagnetic (AFM) semiconductor with loss. An AFM semiconductor is an infinite bi-gyrotropic medium, the effective material parameters of which are twice negative in several frequency ranges. It was found that these frequency regions are in the terahertz range and there are four backward EMEs in them, two of which are TE waves, and the other two are TM waves.
A new approach to the creation of millimeter-wave radio imaging systems is proposed. This approach is based on the use of an array receiver consisting of a densely packed (pixel size - 4 mm) array of planar mixers located in the focal plane of a quasi-optical objective, with application of the frequency-modulated continuous-wave radar technique. It has been demonstrated that the implementation of the heterodyne type of reception makes it possible to increase the distance range of the array radio imaging system up to ~ 100 m while maintaining the angular resolution at the previous level.
The elastic interaction of quantum disks (QDs) in a nanowire (NW), i.e., in a hybrid QD/NW structure with sharp heterointerfaces, is considered for the first time. Within the framework of the defect micromechanics approach, the energy of QD pair interaction is established and it is demonstrated that for QDs with a lattice mismatch of the same sign, an attraction zone appears to each other, depending on the ratio of the axial size of the QD to the radius of the NW. The discovered effect should be taken into account when choosing the modes of formation of hybrid QD/NW structures and in models explaining their properties.
The main results of non-linear optical, spectral and current-voltage characteristics research of pyridine organic conjugated molecule-carbon nanoparticles combined system have been presented. The perspective of these materials further study in global trends of modern search of materials for optical limiting has been demonstrated also in the present paper.
The possibility of using re-reflected waves for sounding bulk water-gas-saturated media after exposure to a shock wave has been investigated. Results are shown using probing pulses.
A hybrid material was studied, consisting of polydimethylsiloxane and silver nanoparticles distributed throughout its volume, its optical and thermodynamic characteristics were calculated for different volume fractions of silver content. It is theoretically shown that this material with a volume fraction of silver of about 30% can be used as an active medium for an optoacoustic transducer with an operating frequency range of about 10 MHz.
The ability of martensitic single crystals Cu 82.5 wt.% - Al 13.5 wt.% - Ni 4.0 to perform work has been investigated. It is shown that weight placed on the crystal is transferred smoothly or by impact during shape memory strain recovery (SMS) Moving depends on the preliminary deformation of the crystal. An influence of the preload on this work is studied. It was found that the transition to the impact mode occurs after preliminary compression of the crystal to the full SMS (~ 9%), when the load is more than twice the stress of the detwinning of martensite. DSC calorimetry showed that after compression to 200–250 MPa and higher sharp narrowing of reverse martensitic transformation (RMT) peak takes place.
Since to the stability of the functional properties of a transparent conducting three-layer structure ZnO:Ga/Ag/ZnO:Ga is important for practical application, we studied its long-term durability and thermal stability in air environment. It has been demonstrated that after prolonged interaction with the air environment at room temperature (~ 1000 h) and further heat treatment in air at temperatures up to 450 ° C (up to 10 h), the three-layer structure retains its integrity and is characterized by a low sheet resistance Rs = 2.8 Ω/sq at average transmittance in the visible range Tav of 82.1%.
The effect of treatment with nanosecond laser pulses on the fatigue resistance of plate samples of recrystallized (grain size of the order of 2-3 µm) commercially pure titanium (grade VT1-0) under cyclic tensile loading is studied. The results of investigations by methods of scanning and transmission electron microscopy of the microstructure of the subsurface layer of the alloy under study after exposure to nanosecond laser irradiation and subsequent fatigue tests are presented.
The influence of irradiation with accelerated electrons (energy 8.5 MeV, dose 5 kGy) on the physical properties of medical devices made of polyethylene terephthalate (PET) by infrared (IR) spectroscopy was studied. The revealed post-radiation changes in the IR spectra can be used to justify the choice of the dose of irradiation of PET products with electrons during the radiation sterilization procedure.
Дважды отрицательные среды на основе антиферромагнитных полупроводников для терагерцевого диапазона частот