bluuebunny/crossref_metadata_2025 huggingface dataset:
In uence of irradiation on the stability of extraction mixtures based on methyltri-n-octylammonium carbonate
Authors: Obedkov A. S. , Bolshakova I. A. , Belova E. V. , Kostikova G. V. , Raitman O. A. , Stepanov S. I.
Published: April 2024

The radiation-thermal stability of extraction mixtures based on methyltrioctylammonium carbonate has been studied. The volumes and maximum rate of release of gaseous products at atmospheric and elevated pressures have been determined. It is shown that exothermic processes do not occur in the studied mixtures under experimental conditions. Irradiation up to a dose of 1 MGy has little e ect on the density, viscosity, and surface tension of mixtures, but signi cantly reduces the rate of phase separation. The distribution coe cients of Am(III) in the system of 50% MTOA carbonate in toluene are practically independent of the absorbed dose; however, irradiation has a noticeable e ect on the composition of the extractable americium complexes. The results of the study of extraction systems showed their high radiation-thermal stability.
«2+1B» tricarbonyl complexes of technetium-99m and rhenium with n,n'-bidentate ligands and methyl 2-(decylthio)-6-isocyanohexanoate
Authors: Miroslavov A. E. , Kuz'min V. V. , Sakhonenkova A. P. , Tyupina M. Yu. , Sidorenko G. V. , Kochergina A. R. , Polukeev V. A.
Published: April 2024

«2+1B» tricarbonyl complexes of the general formula [M(CO)3(N^N)CN(CH2)4CH(COOMe)SC10H21]ClO4, where M = 99 m Tc or Re, N^N = 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen), were prepared by the reaction of [M(CO)3(N^N)(MeOH)]ClO4 with methyl 2-(decylthio)-6-isocyanohexanoate in methanol. The rhenium complexes were isolated and characterized by 1H NMR and IR spectroscopy. The formation of technetium-99 m complexes was con rmed by HPLC. The lipophilicity of the technetium complexes was measured.
Automated synthesis module for L-[11С-methyl]methionine: design, performance, and e ciency in PET
Authors: Kuznetsova O. F. , Orlovskaya V. V. , Vaulina D. D. , Obolentsev V. Yu. , Demyanov A. S. , Krasikova R. N.
Published: April 2024

An automated module for the synthesis of L-[11C-methyl]methionine, a well-known PET radiotracer for brain tumor imaging, has been designed. The module meets modern requirements for the production of radiopharmaceuticals and radiation safety; thanks to the original program created in the Delphi programming environment, module is convenient for the synthesis control (user-friendly) and operation; the service can be maintained on its own with minimal time and nancial costs. The module ensures the production of L-[11C-methyl]methionine with high chemical, radiochemical and enantiomeric purity and a radiochemical yield of 30% (based on [11C]CO2 activity, not decay corrected).
Tritium labeling vancomycin and studying its adsorption on nanodiamonds
Authors: Shen T. , Chernysheva M. G. , Badun G. A.
Published: April 2024

Procedure of tritium labeling vancomycin using tritium thermal activation method has been developed. The influence of target mass on the specific and total radioactivity was revealed. [3H]vancomycin was used for studying its equilibrium adsorption on nanodiamonds as well as its number that tightly bonded with surface and didn’t remove with water. It was found that adsorption from aqueous solution results in tightly bonded vancomycin with nanodiamonds that didn’t removed with water. Application of 0.028 M phosphate buffer (pH 6.7 and 2.7) leads to the equilibrium adsorption growth as much as one and a half times, while vancomycin number in the adsorption complex with nanodiamonds after washing with water was significantly reduced. Such behavior of vancomycin is due to the presence of phosphate-ions that contribute to vancomycin adsorption, but are removed during washing with water. Molecular mechanics simulation allows us to suggest the formation of multiple hydrogen bonds for formation of a durable adsorption complex of vancomycin with nanodiamonds.
Physicochemical mechanisms of dissolved 137CS seasonal variations in freshwaters: Fukushima and Chernobyl
Authors: Konoplev A. V.
Published: April 2024

Analysis of available monitoring data sets on concentrations of accidentally derived dissolved radiocesium in water bodies is indicative of two major physicochemical mechanisms responsible for their seasonal variations in water bodies in the course of the year: temperature dependence of radiocesium desorption from suspended material and ion-exchange remobilization of radiocesium by ammonium cations formed during decomposition of organic matter in anoxic conditions. An equation describing seasonal variations in concentration of dissolved radiocesium in water bodies has been derived accounting for two factors: water temperature and combined concentration of key competing cations.
Comparison of Theoretical and Real Throughput of PD-NOMA
Authors: Kryukov Y. V. , Pokamestov D. A. , Rogozhnikov E. V.
Published: April 2024

In this paper, we compare theoretical and real throughput in PD-NOMA systems. The theoretical throughput was obtained using ideal signal structures according to Shannon’s theorem while the practical one was obtained with allowance for the use of a bank of signal-code structures from the 3GPP LTE standard. An approach for estimating the real throughput of PD-NOMA is described. The error value between the theoretical and real throughput of PD-NOMA is determined.
Simulation and Experimental Study of a Linear Bifocal Antenna Array
Authors: Bankov S. E. , Frolova E. V. , Kalinichev V. I.
Published: April 2024

A leaky-wave bifocal linear array focused in the Fresnel zone is considered. The structural parameters provide perfect focusing of the field at two points corresponding to two different frequencies. An approximate theory of antenna arrays is used to analyze the bifocal array, to study the shape of the frequency scanning arc, and to determine the field distribution in the focal spot. An electrodynamic simulation is performed for a strip array with slotted radiators. The scattering parameters of the array and its radiation characteristicsare presented. The design features of a strip antenna that suppress the effect of normal are discussed. The results of an experimental study of a strip bifocal array are presented. The possibility of implementation of a symmetrical scanning arc and a relatively low level of optical aberrations is shown.
Simulation and Measurement of Snow Cover Thickness Using a Laser Rangefinder
Authors: Grigorievskii V. I. , Marchuk V. N. , Tezadov Y. A.
Published: April 2024

The results of study on determining the height of the snow cover on a site with a relatively flat terrain using a laser rangefinder are presented. Data on the thickness of the snow cover was determined from the dependence of the difference in distances from the reflection point to the rangefinder with and without snow cover in the winter–spring period. The modeling of the determination of the thickness of the snow cover was carried out under the assumption of small irregularities of the measured surface. It is shown that the simulation data may differ from the experimental results up to ~200 mm even on relatively flat areas with a slope of less than 1°, which in some cases is insufficient to predict the impact of snow on snow-covered objects. Comparisonwith other methods for measuring the depth of snow cover is carried out. Possible applications of the technique used in problems of monitoring and remote sensing are discussed.
Investigation of Characteristics of Electromagnetic Bandgap (EBG)
Waveguide in Electromagnetic Crystal with Capacitive Cylinders
Authors: Kalinichev V. I. , Frolova E. V. , Bankov S. E.
Published: April 2024

Electromagnetic bandgap (EBG) waveguides formed in a two-dimensionally periodic lattice of capacitive metal cylinders located between two metal screens are considered. The cylinders have a gap between one of the ends and the screen. It is shown that the lower critical frequencies of such waveguides are shifted upwards in comparison with the corresponding waveguide in the array of solid cylinders, which is dueto the possibility of slow waves propagating in the array in the first zone of its transparency. The critical wave frequencies in the second transparency zone of the capacitive grating are lower than in the grating of solid cylinders. The dependences of the dispersion diagrams and the damping of the main wave on the gap are studied.It is shown that, in most of the operating range, the dispersion curves and attenuation characteristics are practicallythe same as for a waveguide without gaps in the walls. The problem of excitation of an EBG waveguide in a capacitive grating by a standard metal waveguide is solved, and the level of their matching in the frequency band is calculated depending on the size of the gap. The working band of the EBG waveguide for different grating periods is determined taking into account the required level of matching and the limitation from above by the highest wave type of the metal waveguide. It is shown that its maximum value is reached at a certainperiod depending on the size of the gap.
Photoinduced Microwave Permittivity of Semiconductors: Exciton Mechanism
Authors: Butylkin V. S. , Fisher P. S. , Kraftmakher G. A. , Kazantsev Yu. N. , Kalenov D. S. , Maltsev V. P. , Parkhomenko M. P.
Published: April 2024

Significant differences observed in the behavior of photoinduced permittivity ε of semiconductors in the gigahertz (GHz) and terahertz (THz) ranges are explained within the framework of the exciton mechanism by the different position of these ranges relative to the frequencies of exciton interlevel transitions. The measurements in the GHz range of the photoinduced changes of quantities Imε(P_λ) and Reε(P_λ) of CdS, CdSe and Si samples in a waveguide resonator (f = 4.7 GHz) and transmittance T of Si samples in free space (f = 8–36 GHz ) under fiber-optic irradiation (P_λ = 0–370 mW and λ = 0.97 μm) that exhibit non-Drude response prove the theoretical conclusions: an increase in Reε^(GHz)(P_λ) with increasing P_λ and an increase in transmittance T with decreasing frequency f at fixed power P_λ.
Series Connection of a Memristor with Other Discrete Elements: Resistor, Semiconductor Diode, Inductive Coil, and Capacitance
Authors: Kitaev A. E. , Belov A. I. , Huseynov D. V. , Mikhailov A. N.
Published: April 2024

A transition is made from piecewise continuous functions of the memristor model with threshold type switching to differentiable functions described by a single formula. Systems of equations are obtained and numerically solved for circuit sections in which the memristive device is connected in series with other discrete elements, a conventional resistor, diode, inductor, and capacitor. For the case of a serial connection of a memristor and a resistor, the calculated data are compared with the experiment. The case of series connection of a memristor and a semiconductor diode has been studied in detail. The assumptions concerning the mathematical description and physical interpretation of the influence of the molding process on the memristive system are presented.
A Method For Autoregression Modeling of a Speech Signal
Authors: Savchenko V. V.
Published: April 2024

The problem of autoregressive modeling of a speech signal based on the data of the discrete Fourier transform in the mode of a sliding observation window of small duration (milliseconds) is considered. The problem of stability of the formed autoregressive model is investigated. To overcome it, it is proposed to use the envelope of the Schuster periodogram as a reference spectral sample. A new method of autoregressive modeling has been developed, in which the detection of the spectral envelope is carried out using a recirculator of a sequence of samples in the frequency domain. An example of its practical implementation is considered, a full-scale experiment is set up and carried out. Based on the results of the experiment, conclusions were drawn about achieving a significant gain in terms of not only stability, but also the accuracy of the autoregressive model of the speech signal.
Effect of a High-Power Light Pulse on the Trajectory of Magnetostatic Waves in the Presence of a Linearly Nonuniform Field
Authors: Vlasov V. S. , Shavrov V. G. , Shcheglov V. I.
Published: April 2024

The transformation of the trajectories of surface magnetostatic waves propagating in a ferrite film magnetized by a linearly nonuniform field caused by a high-power femtosecond laser pulse is considered. A decrease in the magnetization of the film due to an increase in its temperature can be used to account for the effect of light on wave propagation. The stepwise transformation of the trajectories of propagating waves that is synchronous with the time parameters of the femtosecond pulse is revealed. The transformation of trajectories is interpreted using the method of isofrequency curves and the Hamilton–Auld method.
Magnetocaloric Materials for Low-Temperature Magnetic Cooling
Authors: Koshkid’ko Yu. S. , Dilmieva E. T. , Kamantsev A. P. , Mashirov A. V. , Cwik J. , Kol’chugina N. B. , Koledov V. V. , Shavrov V. G.
Published: April 2024

State of research in the study of magnetocaloric materials based on rare-earth metals that are promising for application in the technology of low-temperature magnetic cooling is reviewed. Physical principles and characteristics of the magnetocaloric effect in materials based on rare-earth metals with low-temperature magnetic phase transitions are presented.
Magnetic and Magnetocaloric Characteristics of the Mn1.9Cu0.1Sb Alloy
Authors: Mitsiuk V. I. , Gurbanovich A. V. , Gurbanovich An. V. , Tkachenko T. M. , Valkov V. I. , Golovchan A. V. , Mashirov A. V. , Surowiec Z.
Published: April 2024

The magnetic and magnetocaloric characteristics of the Mn1.9Cu0.1Sb alloy were studied. The presence of a relatively sharp decrease in the magnetization in the region of 100 K is established, which, according to ab initio calculations, can be interpreted as antiferromagnetism–ferrimagnetism transitions. The presence of a magnetic phase transition from a ferrimagnetic to an antiferromagnetic state (F ↔ AF) leads to the appearance of an inverse magnetocaloric effect, which is preserved in magnetic fields up to 10 T.
Electronic Structure and Properties of the Ground State of Fe–Pt Based Alloys
Authors: Pavlukhina O. O. , Sokolovskiy V. V. , Buchelnikov V. D.
Published: April 2024

The properties of the ground state and the electronic structure of Fe2PtZ (Z = Ga, In, Ge, Si, Sn, Al) and FeRh1 – xPtx in the framework of the density functional theory implemented in the VASP software package alloys have been studied. Densities of electronic states for Fe2PtZ and FePt are obtained. It is shown that in Fe2PtIn and FePt high values of spin polarization are observed. It has been found that with increasing platinum concentration, the staggered antiferromagnetic spin configuration becomes unstable, and in the concentration range above 0.625, the antiferromagnetic configuration with layer-by-layer alternation of magnetic moment directions becomes advantageous. It was found that with a further increase in the platinum concentration, a ferromagnetic phase is observed.
Magnetocaloric Effect in the Laves Phase of GdNi2 in Strong Magnetic Fields
Authors: Kamantsev A. P. , Koledov V. V. , Shavrov V. G. , Plakhotskiy D. V. , Bogush M. Yu. , Utarbekova M. V. , Orshulevich M. A.
Published: April 2024

Experimental studies of the magnetic and magnetocaloric properties of the Laves phase of GdNi2 have been carried out in external static up to 3 T and pulsed up to 50 T magnetic fields. It has been found that in a magnetic field of 3 T the change in the magnetic entropy of the alloy reaches its maximum value ΔSm = −8 J/(kg K) in the vicinity of the Curie temperature TC = 73.6 K. The corresponding adiabatic temperature change in this case, calculated by an indirect method, is ΔTad ≈ 3 K. The maximum value of the adiabatic temperature change measured by the direct method in a pulsed magnetic field of 50 T at T0 = 77 K, was equal to ΔTad = 15 K, which agrees well with theoretical predictions.
Peculiarities of the Formation and Growth of Thin Gold Films on the Surface of Gallium Arsenide during Thermal Evaporation in Vacuum
Authors: Bryantseva T. A. , Lyubchenko V. E. , Lyubchenko D. V. , Markov I. A. , Ten Yu. A.
Published: April 2024

Changes in the morphology and structure of the GaAs surface during the deposition of an Au film by thermal evaporation in vacuum have been studied. It has been found that the deposition of an Au film with the participation of a flow of particles and light from a heated evaporator causes the appearance of photoeffects in the near-surface GaAs layers, including light diffraction on surface acoustic waves, the growth of whiskers, and electron emission, which leads to the formation of microcracks on the GaAs surface and the growth of GaAs crystallites. It is shown that the structure and composition of the film boundaries of Au and GaAs surfaces depend on the electron concentration in gallium arsenide, which ultimately determines the properties of the electrophysical parameters of the Au–GaAs contacts.
Magnetic Isolated Vircator with a Magnetic Mirror on a Prelimit Electron Beam: Features of Beam Dynamics and Superhigh-Frequency Characteristics
Authors: Dubinov A. E. , Kolesov G. N. , Selemir V. D. , Tarakanov V. P.
Published: April 2024

A relativistic magnetically isolated vircator with a magnetic mirror on a prelimit electron beam is proposed. Its computer simulation has been carried out. The phase dynamics of an electron beam in a vircator has been studied. It is shown that a number of virtual cathodes appear in the beam after the beam is reflected from the magnetic mirror. The output microwave characteristics are calculated: the average power and the spectral composition of generation, containing a set of narrow spectral lines and their harmonics. The effect of the mirror ratio on the average output power and on the frequencies of the spectral lines is studied. It is found that the power increases with the growth of the mirror ratio. The frequencies of some spectral lines increase with the mirror ratio, while the frequencies of other lines do not depend on this ratio.
Nonstationary Delay in the Development of Oscillations of a Magnetostrictive Transducer under Conditions of Multiplication
of the Excitation Frequency
Authors: Ivanov A. P. , Shavrov V. G. , Shcheglov V. I.
Published: April 2024

A numerical study of the delay in the excitation of oscillations of a magnetostrictive transducer in the frequency multiplication mode based on the model of coupled oscillators is presented. The non-stationary nature of the oscillations excited after the amplitude jump is revealed. The phenomenon is interpreted on the basis of the dynamic potential model. A numerical study of the development of oscillations in time has been carried out, and phase portraits of oscillations have been constructed. The fractal-like nature of nonstationary oscillations is established, which manifests itself in the preservation of the degree of their chaoticity with a change in the value of the calculation step in time.
Preparation of Single-Crystal Zinc Oxide Films on a Metal Sublayer
Authors: Luzanov V. A.
Published: April 2024

To increase the efficiency of devices based on piezoelectric transducers made of zinc oxide, it is proposed to use single-crystal layers of platinum as the bottom electrode. Epitaxial single-crystal films of zinc oxide on metal have been obtained. It is shown that this combination of layers makes it possible to minimizethe mismatch in the lattice parameters of the film and substrate, which significantly improves the quality of the obtained piezoelectric film.
Recurrent Estimation of Phases Probability Density Function of Modulated Signals
Authors: Maslakov M. L. , Egorov V. V.
Published: April 2024

The problem of constructing an empirical probability density distribution of the phases of a signal with phase shift keying modulation, as well as nonparametric estimation methods, is considered. The transition from the approximation method using basis functions to the method of windowed kernel functions based on harmonic functions is shown. The results of numerical experiments are presented.
Asymptotics of the Localized Bessel Beams and Lagrangian Manifolds
Authors: Dobrokhotov S. Yu. , Nazaikinskii V. E. , Tsvetkova A. V.
Published: April 2024

The Bessel beam-type asymptotic solutions of the three-dimensional Helmholtz equation, i.e., the solutions that have maxima in the vicinity of the -axis and are described by Bessel functions in the planes normal to it, are discussed. Since the Bessel functions slowly decrease at infinity, the energy of such solutions appears unlimited. Approaches to localizing such solutions by representing them in the form of the Maslov canonical operator on proper Lagrangian manifolds with simple caustics in the form of degenerate and nondegenerate folds are described. Efficient formulas for these solutions in the form of Bessel and Airy functions of a complex argument are obtained.
Artificial Magnetic Conductors Based on Frequency Selective Surfaces
Authors: Kazantsev Yu. N. , D’yakonova O. A.
Published: April 2024

New band-passing frequency-selective surfaces (FSSs) are proposed and investigated. Formulas for calculating the modulus and phase of the reflection coefficient of artificial magnetic conductors are obtained based on the proposed FSSs. The comparison of the results of electrodynamic modeling and calculation by formulas is carried out. The possibility of expanding the operating frequency band is shown.
Signal Receiver for Global Navigation Satellite Systems Based on a U-Blox ZED-F9P Module for Ionospheric Research
Authors: Kogogin D. A. , Sokolov A. V. , Nasyrov I. A. , Dementiev V. O. , Zagretdinov R. V.
Published: April 2024

The results of the development of a prototype of the receiver of signals from global navigation satellite systems (GNSS) based on the U-blox ZED-F9P module are presented and a comparative analysis of its characteristics with professional GNSS receivers Trimble Alloy (KZN2 station of the IGS network) and JAVAD TRE-3L in the registration problem is performed. A qualitatively and quantitatively comparable behavior of the studied parameters for all types of GNSS receivers is noted.
Estimation of Probabilistic Characteristics of Reception of Frequency-Effective Signals during Propagation along a Radio Line with Fog
Authors: Nazarov L. E. , Kutuza B. G. , Batanov V. V.
Published: April 2024

A model of a radio line with fog, which is used to represent distortions of complex envelopes of digital signals because of the absorbing and dispersive properties of the propagation medium, has been considered. It is shown that with an increase in the frequency band of digital signals and with an increase in their order of manipulation (when using frequency-efficient signals), the influence of these distortions leads to energy losses in relation to propagation in free space. The quantitative estimation of energy losses for the digital signals used in applications with multi-position phase, quadrature-amplitude, and amplitude-phase manipulations and for a radio line with fog with a variation of its parameters has been carried out. It has been shown that for signals with multiposition phase and amplitude-phase manipulations (the frequency efficiency coefficient of the signals is 4 bits/s/Hz), the energy losses reach 3.5 and 1.0 dB, respectively.
Microwave Radiometric System in Problems of Forecasting Hazardous Atmospheric Phenomena
Authors: Shchukin G. G. , Fedoseeva E. V. , Bulkin V. V. , Rostokin I. N.
Published: April 2024

The main directions of improving radiometric microwave systems for solving problems of ultrashort-term forecasting of the development of adverse and dangerous atmospheric weather phenomena are shown, which consist in solving problems of compensating for the influence of background noise, digital processing of output signals, and including radio-photonic paths and a neural network in the system. The results of correlation processing of data from remote sensing of the surface layer of an inhomogeneous atmosphere in three frequency ranges are presented.
System of Laser Interferometers with a Large Spatial Difference to Study the Seismic-Deformation Oscillations of the Ea
Authors: Dubrov M. N. , Larionov I. A. , Alexandrov D. V. , Kravtsov V. V.
Published: April 2024

The results of unique experiments on synchronous recording of oscillations of earth’s surface with three laser interferometers–deformographs spaced at a distance of 6740 km, obtained during 2016–2020, are considered: two 100-m laser deformographs (Fryazino, Moscow oblast) and one 18-meter (Karymshina site, Kamchatka krai). It is shown that frequency-stabilized and thermocontrolled lasers, as well as systems for registering shifts of the compensation and modulation type interferogram provide an absolute instrumental resolution of 0.1–0.01 nm.
Signal Demodulation Method in the PD-NOMA System Using a Nonlinear Algorithm with Successive Cancellation of Demodulated Components
Authors: Kreindelin V. B. , Varukina L. A.
Published: April 2024

A method for signal demodulation in a system with power-domain non-orthogonal multiple access is proposed. The method implements the principle of successive cancellation of demodulated components taking into account the variance of the estimation error and using a nonlinear function. The results of simulation of the proposed method in a cellular communication system are presented: the use of the proposed method allows an improvement by 1–3.5 dB compared to known algorithms, depending on the power ratio of signals transmitted by three user terminals.
Test Methods for Signal Reconstruction of Linear Stationary Systems
Authors: Novikov-Borodin A. V.
Published: April 2024

The test methods designed for mathematical reconstruction of input signals of linear stationary information processing systems from distorted and noisy output signals are proposed and analyzed. It is shown that the use of test data allows one to carry out a non-blind reconstruction without determining the hardware functions of processing systems, which, in general, can belong to the class of generalized functions. The features of the use of the regularization technique in test methods are considered when solving ill-posed and ill-conditioned problems of reconstruction of real non-deterministic signals. The criteria for selecting test signals are analyzed. The results of numerical experiments on the restoration of one-dimensional signals and two-dimensional images at different noise levels are presented.
Propagation of Powerful Nano- and Subnanosecond Video Pulses in a Medium with Various Thermodynamic Characteristics
Authors: Glazunov P. S. , Vdovin V. A. , Saletskii A. M.
Published: April 2024

A conservative model is proposed for a weakly conductive material medium with changing thermodynamic characteristics during the propagation of a pulse in it. Equations are obtained that describe the change in the shape of the profile of a video pulse propagating in a medium, as well as in nonlinear transmission lines with a temperature dependence of the permittivity. It is shown that if the temperature coefficient of the permittivity is negative, then the peak power of the pulse can increase with time; otherwise, the temperature dependence of the permittivity leads to an increase in attenuation.
Algorithmic Solutions in the Problem of Evaluating the Quality of Communication with an Unmanned Aerial Vehicle
Authors: Polyanskii I. S. , Shapovalov Ya. D.
Published: April 2024

Algorithmic solutions have been developed to assess the quality of communication with an unmanned aerial vehicle. The quality of communication is determined by the probability of a symbol error at the input of an error-correcting encoder, the a priori calculation of which is performed in the approximation of Rice’s communication channel model. The main attention in the solution is given to the determination of attenuation due to the combined influence of the terrain and tropospheric refraction on the energy parameters of the line ground communication point–unmanned aerial vehicle. The attenuation was calculated by jointly solving a pair of parabolic equations formed from the two-dimensional Helmholtz equation in narrow- and wide-angle approximations by the pseudospectral method of separating the steps of a pair of parabolic equations. In the features of the main stages of the algorithmic implementation of the developed solution are highlighted, and its performance is tested on specific test examples.
Metal–semiconductor–metal detectors ZnS/GaP for the ultraviolet and visible part of the spectrum with electrically tunable spectral photosensitivity
Authors: Averin S. V. , Zhitov V. A. , Zakharov L. Yu. , Kotov V. M. , Temiryazeva M. P.
Published: April 2024

High-quality ZnS epitaxial layers grown on GaP semiconductor substrates by MOCVD method. Photodetectors of the visible and UV parts of the spectrum based on new interdigitated Schottky barrier metal–semiconductor–metal (MSM) contacts to semiconductor structure ZnS/GaP. The detectors exhibit low dark current values. The dependence of the characteristics of the spectral response of detectors on voltage has been established offsets. It was found that the long-wavelength response boundary of ZnS/GaP MSM detectors can shift from 355 to 450 nm when the bias voltage changes from 10 to 30 V. At the maximum photosensitivity wavelength of 450 nm, the ampere-watt sensitivity of the detector was 0.3 A/W at a bias voltage of 60 V, and the quantum efficiency was 82%.
A parametric family of spline-based finite impulse response filters and a method for finding the optimal parameter
Authors: Budunova K. A. , Kravchenko V. F.
Published: April 2024

A new parametric family of filters with finite impulse response is proposed based on convolutions of splines with a rectangular impulse. An algorithm for searching for a parameter that optimizes the deviation of the amplitude-frequency characteristic in passbands and suppression bands. A numerical experiment was carried out, which involved comparing research of new filters with window filters and optimal Chebyshev filters.
Method of correlation reception of radio light with spatial resolution and its implementation
Authors: Petrosyan M. M. , Ryzhov A. I.
Published: April 2024

A method for receiving ultra-wideband noise-like microwave radiation -- radio light is considered, based on the correlation reception of signals coming from spaced apart space of receiving antennas, for the purpose of further effective image formation radio-illuminated environment. A mathematical model has been developed to study the formation possible response of the receiving system and assessing the influence of signal accumulation time on its dynamicrange. One-dimensional responses of the correlation receiving system to point sources of radiation were obtained, for which radio light sources were used. An experimental model of a correlation radio light receiver was developed and physical experiments were carried out with it, confirming the results obtained during modeling, as well as the overall performance of the proposed approach.
Construction of wavelets based on exponential atomic functions hup_a (x) and harmonic scup_ b (x) and g_k (x).
Authors: Kravchenko V. F. , Konovalov Ya. Yu.
Published: April 2024

The possibility of constructing wavelets based on convolutions with a rectangular pulse of exponential and harmonic atomic functions is investigated. Some properties of exponential and harmonic atomic functions are considered. The values of the uncertainty constants of the constructed wavelets are calculated.
Texture-fractal analysis of polarimetric images generated by synthetic aperture radar stations.
Authors: Kuznetsov V. A. , Potapov A. A.
Published: April 2024

All currently known methods and methods for the formation of fractalfeatures of polarimetric radar images. Briefly reviewed newtexture-fractal feature – a directional multifractal signature measured morphologically by the iterative covering method. In relation to the analysis of polarimetric images formed by a synthetic aperture radar, a new concept for their processing is proposed, based on the possibility of taking into account the polarization differences of ground-based spatially distributed objects by identifying the multifractal and anisotropic properties of their texture. A variant of interpretation of the obtained results for automatic optimization of further successful solution of specific segmentation (classification) problems underlying surface, detection and recognition of ground objects.
Spin magnetoresistance of thin film structures of manganite and material with strong spin-orbit interaction.
Authors: Ul'ev G. D. , Constantinian K. I. , Moskal' Y. E. , Ovsyannikov G. A. , Shadrin A. V.
Published: April 2024

The results of the experimental determination of the spin Hall angle in a two-layer metal/ferromagnet structure Pt/La_0.7 Sr_0.3 MnO_3, obtained from the angular dependences of the longitudinal and transverse spin magnetoresistance in the planar Hall effect configuration are presented. The spin Hall angle determined from the longitudinal magnetoresistance was θ_Hx ≈ 0.016, and from transverse θ_Hy ≈ 0.018, while for SrIrO_3/La_0.7 Sr_0.3 MnO_3 heterostructures the ratio of the transverse to longitudinal spin Hall angle turned out to be significantly higher, θ_Hy/θ_Hx ≈ 9, which is most likely caused by the formation of a layer with high conductivity at the SrIrO_3 boundary /La_0.7 Sr_0.3 MnO_3.
On the Problems of Monitoring Atmospheric Humidity Fields Using Satellite Microwave Radiometry Methods When Studying Cyclogenesis in the Tropical Atlantic
Authors: Grankov A. G. , Novichikhin E. P. , Shelobanova N. K.
Published: April 2024

Some problems of microwave radiometric methods for monitoring fields of total atmospheric moisture content from satellites in areas of hurricane formation in the tropical regions of the Atlantic are considered. The possibilities of using polar-orbiting satellites (DMSP, EOS Aqua, GCOM-W1) for these tasks are analyzed a feature of which is the presence of gaps in satellite data (blind spots) resulting from divergence of scanning bands at lower latitudes. It is shown through a number of examples that the joint use of various satellites makes it possible to reduce the influence of this effect and obtain a clear picture of the evolution of atmospheric humidity fields in the tropical Atlantic and their connection with the evolution of tropical waves that initiate the formation of hurricanes.
Portable Fourier Spectrometer and Features of Its Electronics
Authors: Martyanov P. S. , Vagin V. A. , Khorokhorin A. I.
Published: April 2024

The electronics features of a portable infrared Fourier transform spectrometer are considered. A description of its most important components and justification for the use of the corresponding element base are given; structural diagrams are outlined, an analysis of the most significant electronic units of the device and their functioning is carried out. The results of experimental studies are presented.
Elemental Composition of Reindeer Pasture Plants and Lichens in Nadym District (Yamal-Nenets Autonomous Area)
Authors: Boldyreva E. A.
Published: April 2024

Abstract—There are plans to expand reindeer husbandry in the Nadym District of the Yamal-Nenets Autonomous Area. For this purpose, we studied the elemental composition of the dominant species of the tundra and open boreal woodland vegetation cover. We analyzed leaves of dwarf birch (Betula nana L.), dwarf shrubs of bog blueberry (Vaccinium uliginosum L.), marsh Labrador tea (Ledum palustre L.), and leatherleaf (Chamaedaphne calyculata (L.) Moench); sphagnum moss (Sphagnum sp. L.); and fruticose lichens (Cladina stellaris (Opiz.) Brodo). The X-ray fluorescence analysis was used to obtain data on the content of Ca, K, P, Si, Mg, Na, S, Zn, Cu, Ni, Co, Fe, Mn, Cr, Ti, and Al. We defined the biogeochemical features of the reindeer forage plants. In vascular plants and sphagnum mosses, the content of almost all essential macroelements is low, while the content of most microelements (Cu, Ni, Co, Cr, and Mn) exceeds the world average values. The lichens are characterized by low concentration of Ca, K, Mg, and P, which is more than one order of magnitude lower than the world average values, and the deficiency of microelements. The results were compared with the results from similar studies in other geographical regions of the tundra zone, and it was found that tundra plants have a similar pattern of element accumulation. In particular, leaves of dwarf birch are distinguished by accumulation of Mg; the content of Al, Fe, and Si is increased in mosses; Mn is accumulated in dwarf shrubs and dwarf birch; lichens are characterized by the deficiency of most elements. Therefore, in order to prevent animal diseases, it is necessary to improve the elemental composition of reindeers feed by increasing the share of “green” forage in winter, when lichens dominate the diet.
The Content of Ash Elements in the Above-Ground Organs of Some Crataegus (Rosaceae) Species
Authors: Mukhametova S. V. , Demakov Yu. P. , Talantsev V. I.
Published: April 2024

Abstract—The study assessed the content of ash elements in the dry matter of fruits, flowers and leaves of 19 hawthorn (Crataegus L.) species. The plants from the collection of the Botanical Garden-Institute of the Volga State University of Technology (VSUT), the Mari El Republic, were studied. The content of eight elements was determined by atomic absorption spectrometry. It is shown that ash and trace elements content is species-specific. The ash content in dry fruits is highest in C. flabellate (Bosc) K. Koch and C. macracantha Lodd., and lowest in C. × almaatensis Pojark. and C. altaica (Loud.) Lange. The highest content of Fe was found in C. pinnatifida Bunge, Mn – in C. flabellate (Bosc) K. Koch, Zn – in C. volgensis Pojark., C. maximowiczii C.K. Schneid. and C. nigra Waldst. et Kit., Cu – in C. volgensis Pojark., Ni, Sr and Co – in C. macracantha Lodd., Cd – in C. altaica (Loud.) Lange, C. macracantha Lodd., C. volgensis Pojark. Difference in the fruit elemental composition between hawthorn species may be due to the difference in proportion of pulp and seeds. The content of ash and mineral elements in hawthorn fruits varies depending on the growing season conditions. The content of Fe, Zn and Ni increases in years with warm and humid summers, while the content of Mn decreases, but the weather conditions of the growing season account for only 3.8 to 28.8% of the variance of values. In hawthorn, the concentration of trace elements essential for humans, especially Zn, is significantly higher in flowers, than in fruits, and, on the contrary, concentration of potentially toxic Sr is higher in fruits. In leaves, especially harvested in autumn, Sr content is tens of times higher than in fruits.
Assessing the Adaptive Capacity of Salix, Chosenia and Toisusu (Salicaceae) Species Introduced in the North-West Region of Russia (St. Petersburg)
Authors: Yandovka L. F. , Trofimova A. S. , Dvoretskaya T. S.
Published: April 2024

Abstract—The study of the adaptive capacity of the introduced plants is an important component of willow breeding. The characteristics of vegetative organs and species’ reproductive ability were used as adaptation indicators. Insufficient knowledge of vegetative and generative structures adaptability in introduced Salicaceae species established ground for the study. It was aimed at identifying Salicaceae species most adapted to the climatic conditions of the North-West region of Russia. The specimens of Salix, Chosenia and Toisusu in the family Salicaceae, introduced in the Botanical Garden of Peter the Great of the Komarov Botanical Institute were studied and compared with the Salicaceae species native to the region. In the examined species the values of shoot extension over the growing season, winter hardiness of flower buds and stems, and seed productivity were determined. The article assesses the characters’ variations, which in some cases demonstrate the species instability under new conditions. The most stable indicators of shoot extension and sufficient winter hardiness of flower buds are found in introduced in St. Petersburg Salix vinogradovii and S. integra. The most stable values of these indicators in plants of the local flora are in S. phylicifolia and S. caprea.
Effect of Dry Storage on Seed Germination of Ephedra monosperma (Ephedraceae)
Authors: Borisova S. Z.
Published: April 2024

Abstract—Effects of dry storage under ambient laboratory conditions on germination and survival was tested for seeds of rare species Ephedra monosperma. The seeds without pregermination treatment were placed in Petri dishes with a moistened filter paper at room temperature 20 ± 3 °C. Seeds maintain high germination when dry stored for 5 years (mesobiotic), further storage leads to a sharp decrease in germination. At the same time, dry storage of seeds does not change the time of the beginning of germination, the duration of germination and the curve of seed germination. Freshly harvested seeds and seeds stored at room temperature germinate 2–4 days after seeding, 50% of seeds – in 7 days, and 98–100% – within 2 weeks. The seed germination curve has two peaks; the highest one is the first, which is observed on the 3rd day from the start of germination.
Structure of the Ground Vegetation and Natural Regeneration of Tree Species in a 12–15-Year-Old Bilberry Pine Forest–Clear-Cut Ecotone Complex in the Middle Taiga Subzone
Authors: Genikova N. V. , Moshnikov S. A. , Teslya D. V.
Published: April 2024

Abstract—Logging in mature stands, where part of the forest is harvested in one or several cuts and part is retained (clear-cutting and alternate strip cutting) results in the formation of an ecotone complex: forest (F), transition from forest to clear-cut under the canopy (forest edge – FE), transition from forest to clear-cut outside of the canopy (clear-cut edge – CE), and the clear-cut itself (C). Strips 8 m wide on each side of the mature forest/clear-cut site border form the transitional zone. We studied the ground vegetation composition and structure, and the natural regeneration of woody species (Pinus sylvestris L., Picea abies (L.) H. Karst., Betula sp., Populus tremula L., Sorbus aucuparia L., Juniperus communis L.) in the bilberry pine forest – clear-cut ecotone complex 12–15 years after the stand removal. The studies demonstrate that each of the four zones of the ecotone complex formed after logging of the mature forest has its own structural features of ground vegetation and undergrowth (including tree regeneration). The typical forest (F) habitat is characterized by the minimum number of young regeneration of Pinus sylvestris, Picea abies, Betula sp., Populus tremula, and Sorbus aucuparia and, on the contrary, by the highest abundance of lingonberry V. vitis-idaea L. and bilberry Vaccinium myrtillus L., and the maximum height of bilberry plants and their yield. The amount of tree regeneration in the FE is almost the same as in the F zone. The projective cover, maximum shoot height and yield of bilberry, and maximum shoot height of lingonberry in the FE zone are reliably lower than in the F zone. The transitional zone on the clear-cut side (CE) and the clear-cut itself (C) are distinguished from the forest sections of the ecotone complex (F and FE zones) by a greater number of deciduous and pine regeneration and the low abundance of dwarf shrubs. The clear-cut itself (C) differs from the CE by the higher abundance of grasses and forbs and an established tree regeneration layer composed of pine, birch, and aspen.
Effect of Urban Environment on Ecological and Phytochemical Features of Crataegus fallacina (Rosaceae) Flowers (the Case of the Donbass)
Authors: Vinogradova N. A. , Glukhov A. Z.
Published: April 2024

Abstract—The article presents the results of a study of the effect of urban environment in the Donbass on the content of biologically active substances, heavy metals and antioxidant activity of the flowers of Crataegus fallacina Klok., a poorly studied non-pharmacopoeial species of the genus Crataegus L. Under technogenic pollution, in the flowers of C. fallacina a decrease in the concentration of carotenoids and an increase in the content of phenolic compounds (flavonoids, procyanidins, oxycinnamic acids, tannins, anthocyanins), ascorbic and free organic acids was detected. The hermetic response of the content of anthocyanins and procyanidins to the pollution level was observed. The flowers of C. fallacina have a high total antioxidant activity, which increases under technogenic load, indicating plants sufficient adaptation to the urbanized environment. The ability of C. fallacina plants to limit flow of cadmium and lead to generative organs was revealed. The concentration of mercury in flowers exceeds its concentration in soil. C. fallacina flowers harvested in the Donbass meet the regulations on the content of active substances and comply with the requirements with regard to the heavy metals content. The obtained results prove the practicability of using C. fallacina for pharmaceutical purposes along with pharmacopoeial species of the genus Crataegus, and the possibility of their harvesting for medicinal use in the Donbass.
Component Composition and Some Features of the Biological Activity of Viscum album (Viscaceae)
Authors: Adzhiakhmetova S. L. , Chervonnaya N. M. , Pozdnyakov D. I. , Popova O. I. , Oganisyan E. T.
Published: April 2024

Abstract—The review summarizes data on the chemical composition and some features of biological activity of Viscum album L. (Viscaceae Batsch). Among the secondary metabolites, the dominant ones are: viscotoxins, lectins, carbohydrates, amino acids, flavonoids, triterpene acids, nitrogenous compounds. It has been shown that European mistletoe extracts, as well as individual components, exhibit various types of biological activity, including antitumor, immunomodulatory, antidiabetic, and improve cognitive functions. V. album is very promising for further comprehensive study as a local source of herbal preparations, as mistletoe preparations are prescribed as an adjunct treatment for cancer patients in many countries.
Phytochemical Characteristics and Antimicrobial Effects of Nonea rossica (Boraginaceae) Extracts
Authors: Velichko V. V. , Kartashova M. E. , Kucherova S. D. , Kruglov D. S. , Burova L. G. , Evstropov A. N.
Published: April 2024

Abstract—A phytochemical and microbiological analysis of a widespread Russian species, Nonea rossica Steven (Boraginaceae) was carried out. As an object of study, we used the aerial part (herb) of N. rossica, harvested during flowering stage from a steppe meadow in the Novosibirsk region. The qualitative composition of biologically active compounds (BAC) was determined by thin layer chromatography, using two solvent systems: ethyl acetate–ethanol–dimexide and ethyl acetate–anhydrous formic acid–glacial acetic acid–water. The quantification of their amount was carried out by spectrophotometry (flavonoids expressed as rutin, hydroxycinnamic acids – as caffeic acid, and coumarin-like compounds – as coumarin). The raw material ethanolic extracts of different concentrations (20, 40, 70 and 95%) were used in pharmacological research. Antimicrobial activity was determined by the serial dilution method. Strains of gram-positive bacteria (Staphylococcus aureus ATCC 6538 FDA 209P and Bacillus cereus ATCC 10702) and fungi – Candida albicans NCTC 885-653 were used as test cultures. The presence of bioactive phenolic compounds (hydroxycinnamic acids, flavonoids, coumarins) was established and their quantitative content was determined. It was observed that the highest yield of bioactive phenolic compounds resulted from using 40–70% ethanol as extractant. The microbiological activity of hydroalcoholic extracts from Nonea rossica herb was studied. It was determined that antimicrobial activity against Staphylococcus aureus and Bacillus cereus, and antifungal activity against Candida albicans were exhibited by 40–70% ethanolic extracts of Nonea rossica, where equal content of caffeic acid and coumarin was measured. The synergistic interaction of these compounds determines the established bactericidal and fungistatic properties of such extracts.