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Vol 70, No 9 (2025)
Articles
Yuri Vasilyevich Gulyaev (on his 90th birthday)
Journal of Communications Technology and Electronics. 2025;70(9):789-790
789-790
ON THE 90th ANNIVERSARY OF Yu.V. GULYAEV
Investigations of internal gravity waves by using radio occultation temperature data in the Venus's atmosphere
Abstract
Based on the previously developed method for identifying narrow-spectrum wave events, a threshold discrimination criterion for internal gravity waves (IGWs) has been established and substantiated upon fulfillment of which the analyzed fluctuations can be considered as wave manifestations. This method is universal in the sense that it can be used to analyze specified vertical profiles obtained by any methods both in the Earth’s atmosphere and in the atmosphere of other planets. Application of the developed method to temperature profiles reconstructed from radio occultation measurements of the Magellan satellite gave us the opportunity to identify narrow-spectrum wave events in the Venus’s atmosphere and to determine key IGW characteristics, such as: intrinsic frequency, amplitudes of vertical and horizontal disturbances of wind speed, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase velocities, and others.
Journal of Communications Technology and Electronics. 2025;70(9):791-797
791-797
Increasing the Sensitivity of the Marine Low-Frequency Electric Field Sensor
Abstract
The possibility of increasing the sensitivity of a marine electrode sensor of a low-frequency electric field with cylindrical electrodes is shown by selecting the location of the electrodes on the surface of the dielectric fairing of the sensor.
Journal of Communications Technology and Electronics. 2025;70(9):798-803
798-803
Errors of quasi-optimal algorithms with reassignment of continuous parameters values for receiving and processing BOC signals in global navigation satellite systems
Abstract
Based on the Markov theory of estimation of random processes by the method of reassignment of values of continuous parameters, analytical expressions are obtained for the variance of the quasi-optimal conditional error of phase estimation and for the probability of erroneous reception of a discrete parameter of the received signal. The problem is solved with respect to noise-like signals and, in particular, BOC signals intended for use in global navigation satellite systems such as GPS (USA), Galileo (European Union), GLONASS (Russia) and BeiDou (China). The results of calculating the characteristics of accuracy and noise immunity of these parameters, obtained using the application software package, are presented. The corresponding graphs are constructed.
Journal of Communications Technology and Electronics. 2025;70(9):804-818
804-818
Locally non-equilibrium electro-magneto-temperature excitations in a continuous medium
Abstract
It is shown that there exists an instability of longitudinal non-equilibrium thermo-polarization-magnetic excitations in the wave number interval for high thermal conductivity and long subsystem coupling relaxation times.
Journal of Communications Technology and Electronics. 2025;70(9):819-827
819-827
Characteristics of magnetic structures determining spin-injection terahertz radiation
Abstract
It is shown that spin-injection terahertz (THz) radiation can be excited at almost any angle of mismatch between the magnetization vectors of the magnetic transition layers. The main characteristics of the magnetic layers influencing the process of THz radiation excitation are determined. Experimental results are presented that prove the non-thermal nature of the radiation produced in a spin-injection radiator with unidirectional orientation of the magnetization vectors of the magnetic transition layers.
Journal of Communications Technology and Electronics. 2025;70(9):828-834
828-834
Registration of the penetration of enzymatically modified nanocomposites containing maghemite nanoparticles through lipid membranes
Abstract
A visual registration of the penetration of enzymatically modified nanocomposites containing maghemite nanoparticles through planar model bilayer asolectin membranes was conducted. Transmembrane current traces were obtained at the moment the nanocomposites passed through the membrane. Transmembrane current spikes were detected, arising during the translocation of nanostructures through the membrane. The measured transmembrane current magnitude allowed estimation of the size of the transmembrane pore to be approximately 10 nm. This pore size closely matched the average diameter of the maghemite nanoparticles comprising the original nanocomposite.
Journal of Communications Technology and Electronics. 2025;70(9):835-843
835-843
Thin Au+Ge Film Growth on the GaAs Surface During the Process of Thermal Avaporation in Vacuum
Abstract
The morphology and structure of thin films were studied during the deposition of Au+Ge on the GaAs surface by thermal evaporation in a vacuum in order to create metal-semiconductor contacts with a reduced barrier height. It was found that the addition of germanium to the evaporated sample ensures the formation of a layer, doped with donors and prevents the transformation of GaAs into a hexagonal structure.
Journal of Communications Technology and Electronics. 2025;70(9):844-850
844-850
The interruption of the generation of a narrowly focused component of stimulated picosecond emission of the AlXGa1–XAs–GaAs–AlXGa1–XAs heterostructure produced by a part of the component reflected from the end face
Abstract
Experimentally, new characteristics of the effect of interrupting generation in the AlxGa1–xAs–GaAs–AlxGa1–xAs heterostructure of a narrowly directed (exiting from the end of the hetero-structure in a certain direction) spectral component of picosecond stimulated emission have been established. These characteristics are dependencies on the distance between the center of the active region and the end of the heterostructure of: a) the duration of the component at the base; b) the energy of that part of the component reflected by the end face, upon passage of which through the active region, the generation of the component is interrupted.
Journal of Communications Technology and Electronics. 2025;70(9):851-857
851-857
Identification of liquid substances of similar chemical composition by the acoustic method
Abstract
A comprehensive approach to processing the responses of Lamb acoustic waves propagating in piezoelectric plates with a liquid coating has been developed, which allows for the differentiation of liquids with similar chemical composition and electrical conductivity. The technique is based on the registration of the amplitudes of zero-order and higher-order Lamb modes in a multi-channel sensor system and the application of polar histogram visualization and principal component analysis (PCA) methods to process the measured data arrays. The technique was tested using 33 acoustic modes for 8 samples of mineral water collected from various sources in the North Caucasus. It was found that even when the compositions are similar, the analyzed liquids exhibit differences in their histograms that are more than an order of magnitude. Changes in the responses were observed during the storage of the samples, indicating the “aging” of the substance. A comparative analysis of the results obtained using polar histograms and the standard PCA classification method was performed. The obtained results are of interest for the development of sensors that do not require sensitive coatings, as well as for integration with machine learning algorithms when working with other types of sensor data.
Journal of Communications Technology and Electronics. 2025;70(9):858-867
858-867
Application of Multi-Frequency Acoustic Field in Acousto-Optic Filters of Geostationary Lightning Mappers
Abstract
A comprehensive approach to processing the responses of Lamb acoustic waves propagating in A new method for analyzing lightning discharge optical radiation is proposed. It based on the use of a tunable acousto-optic filter, in which a multi-frequency acoustic field is created. The filtering of the three most intense lightning radiation lines OI(1), NI(3), NI(1) is studied. For a frequency-equidistant HF signal in acousto-optic filter the ratio of wavelengths for three frequency and passbands is calculated. Differences in published data on the position of spectral maxima of lightning optical radiation are analyzed.
Journal of Communications Technology and Electronics. 2025;70(9):868-873
868-873
Asymmetry of filtering properties of zeros and first Bragg orders
Abstract
The effect of Bragg diffraction occurring in the tangential geometry of the acousto-optic (AO) interaction on the speckle structure of the zero and first diffraction orders is investigated. It is established that in the first order, the fine-grained background of the speckle structure is significantly suppressed in comparison with the zero-order structure. Experiments have been performed on filtering speckle-containing optical radiation with a wavelength of 0.63 microns using an AO cell from TeO2 operating in tangential diffraction geometry at a sound frequency of 100 MHz. A decrease in the fine-grained background in the first order was revealed by ~7 times in comparison with the speckle structure of the zeros order of diffraction.
Journal of Communications Technology and Electronics. 2025;70(9):874-878
874-878