Abstract Nanoparticles of iron (α-Fe) and iron oxide (Fe3O4) with a core-shell structure (α-Fe core, Fe3O4 shell) covered with additional graphite-like carbon layer have been synthesized. The samples were obtained by solid-phase pyrolysis of iron phthalocyanine (FePc) at a pyrolysis temperature of 1000°C, followed by annealing in an oxygen atmosphere at a temperature of 250°C. The composition, structure

Abstract An experimental set-up for hard X-ray off-axis Fresnel holography, based on a two-block Fresnel zone plates interferometer is proposed and analyzed. It is shown, that the suggested scheme provides a recording of the hologram and further numerical reconstruction of the image. The advantage of this scheme, compared with the earlier presented analogous scheme of on-axis holography, based on the

Abstract Doping of thermoelectric materials with various additives is a promising approach for increasing the functional efficiency of thermoelectric materials of different classes. This paper presents preliminary results of studying the impact of the strontium borate dopant Sr(BO2)2 on the power factor (PF) of the oxide thermoelectric Bi2Sr2Co1.8Oy. Samples with the nominal composition Bi2Sr2–x[Sr(BO2)2]xCo1

Abstract The aim of this study is the further development of the technology of Ga67 medical radioisotope production by irradiating a zinc target with natZn67(p,xn)Ga67 reaction. The irradiation was carried out with a proton beam generated by C18 cyclotron which was put into operation in June 2019 in the vicinity of the A. Alikhanyan National Science Laboratory (YerPhI). At present, the cycle of research

Abstract The verification scheme in the package “Professor2” for setting parameters of the most used physics generator PYTHIA8.2 for simulating the processes in high energy physics is described. The goal is to tune the PYTHIA8.2 parameter list for the fragmentation process below \(b\bar {b}\) the production threshold. As an initial parameter list, we use the Belle (predecessor of the Belle II experiment)

Abstract The state of polarization is an important feature of any laser emission. The polarization of light is important for the processing of laser beams in polarization-dependent devices such as interferometers, optical amplifiers, optical modulators, etc. In this paper, the polarization of lasing generated from the three-layered cholesteric liquid crystal–dye-doped polymer layer–cholesteric liquid

Abstract The use of a method developed in the CLAS collaboration (Jefferson Lab, USA) to extract events of quasi-real photoproduction on nuclei from experimental data of electroproduction, as applied to the reaction of near-threshold photoproduction of the J/ψ-meson is described in this paper. Experimental data of electroproduction on a liquid hydrogen target, which was obtained on CLAS12 experimental

Abstract A technology has been developed for obtaining a semiconductor solid solution SnO2 + Nb2O5 (80 : 20 wt %) and for manufacturing a thin-film nanoscale resistive sensor. The gas-sensitive characteristics of the sensor to various concentrations of liquefied petroleum gas (LPG) have been investigated. The SnO2❬Nb❭ sensor detects sensitivity to LPG from an operating temperature of 250°C when exposed

Abstract Coupled cycloidal diffractive waveplates (CDWP) can be used for double diffraction or collinearly propagation of laser radiation of the corresponding wavelength. Adding a doubly refracting and dichroic film between them enables one to obtain the finite transmission even in the absence of double refraction. Both in the cases of two parallel and antiparallel vector gratings, we have an achromatic

Abstract The paper presents and discusses works carried out both at Yerevan State University and abroad on non-invasive metal oxide sensors (chemiresistors) for acetone exhaled by a diabetic. The technologies and parameters of chemiresistors based on tin dioxide, tungsten trioxide, zinc oxide, Fe2O3, In2O3 and TiO2 developed at YSU and in the world are presented. Most likely, it makes sense to start

Abstract A sensor sensitive to acetone vapors based on a Fe2O3❬Sn❭ metal oxide solid solution was fabricated by high-frequency magnetron sputtering. The gas-sensitivity of the manufactured sensor are investigated. The Fe2O3❬Sn❭ sensor shows sensitivity to acetone vapors starting from a temperature of 150°C under the influence of ultraviolet rays. The increase in operating temperature was accompanied

Abstract To get around the difficulty that the singular nature of the potential function V(x) = V0/|x|α introduces into physics, the regularization methods are used. However, they affect the singular nature of the problem, and so we discuss here how quantum tunneling behaves if the original singular nature of the Schrodinger equation remains unperturbed. For this purpose, I am starting from the precondition

Abstract Results of the characterization and numerical analysis of InAsSbP composition strain-induced micro- and nanostructures shape transition are presented. Nucleation is performed from In-As-Sb-P quaternary composition liquid phase in Stranski–Krastanow growth mode. Geometric features and the shape transformation chronology of truncated pyramidal islands, lens-shape and pyramidal quantum dots (QDs)

Abstract New expressions have been obtained to estimate the graphene thermal conductivity coefficient as well as characteristic dependences of coefficient of thermal conductivity on temperature and linear coefficient of thermal expansion. It has been shown that within a wide range of temperatures (about 100–700 K), the thermal conductivity values both computed and experimental ones are in good agreement

Abstract Under the two-wave dynamical diffraction conditions, the wave-field passed through a periodic object is formed in a crystal. The dynamical diffraction Talbot effect in the crystal takes place. The estimates for the required spatial and temporal coherence of the incident radiation are provided.

Abstract For better visualization of solvent effects on spin-spin coupling constants (SSCCs) we have investigated some organomercury compounds, which have large solvent induced changes on one-bond C-Hg SSCCs. Extra large solvent effects (up to 20% of SSCC value) have been observed, which allow to more carefully examine the peculiarities of SSCC’s solvent and electric field dependencies in various media

Abstract This paper reports the results of the investigation of second order optical nonlinearity, as well as the polarization nonlinear behavior of Zn4B6O13. For experiments samples were prepared by thermal treatment of glass tapes and solid state synthesis. The tapes were obtained by a rapid melt quenching technique. The thermal processes in the glass tapes were investigated by differential thermal

Abstract The binding peculiarities of methylene blue (MB), methyl violet (MV), and Hoechst 33258 (H33258) with human serum albumin (HSA) have been studied using the fluorescence spectroscopy method. Based on the fluorescence spectra analysis, it was shown that the HSA binds to the all mentioned ligands and forms complexes, meanwhile, a quenching of the ligand fluorescence occurs, which was found to

Abstract The results of the simulation modeling of single-stranded DNA adsorption on the surface of a single-walled carbon nanotube performed by the molecular dynamics method using the GROMACS software package are presented. The dependence of the timescale and degree of the DNA adsorption was studied against the chirality of the carbon nanotube and the DNA sequence.

Abstract The production of the therapeutic 186gRe radioisotope by proton-induced natW(p,xn) reaction at the cyclotron C18/18 was investigated. The cyclotron is located at the A. Alikhanyan National Science Laboratory (Yerevan Physics Institute). The excitation function of the reaction in the proton energy range from the reaction threshold up to 18 MeV was measured. The measurements were carried out

Abstract Noninvasive in vivo measurements of glycemia in 8 living non anesthetized mice were done using a microwave spiral sensor (MSS). The D-glucose concentration in the blood of the animals was measured in the 80–350 mg/dL concentration range using microwaves of frequencies from 4–5 GHz. Aqueous D-glucose solution with concentrations from 0 to 6% was orally injected into the mice and the change

Abstract The behavior of iron in the translucent dark-gray obsidian from the Artheni deposit was studied by optical absorption and EPR spectroscopy. The presence of iron in the Fe2+ and Fe3+ states was shown. Transitions in optical spectra and paramagnetic centers in EPR spectra were identified. By the methods of prompt gamma activation analysis (PGAA) and neutron activation analysis (NAA), the content

Abstract The results of modeling heat propagation processes in the four-layer SiO2/W/FeSb2/W detection pixel of thermoelectric single-photon detector after absorbing more than one IR photon are presented. The calculations were carried out by a three-dimensional matrix method for partial differential equations. The cases of both simultaneous absorption of several photons on a 1-μm segment of the absorber

Abstract In this work, a theoretical model of the full population transfer in a five-level M type system is demonstrated. The method is based on the technique of linear scanning of the frequency of the laser field close to the resonance frequency of the corresponding transition. A comparison of the full population transfer obtained with the chirping technique with the results obtained by the method

Abstract Wind energy is one of the main factors in the future transition to renewable energies. Hence, it is important to understand how much work can be extracted from the kinetic energy of the wind. Understanding these constraints is important for setting correct strategic goals in wind power research and industry. The current standard opinion is that the limits on the efficiency of work-extraction

Abstract A microwave (MW) method has been developed for the preparation of a ZnO/Ag nanocomposite using methods of chemical precipitation and decomposition of thermally unstable compounds. Chemical co-deposition is a simple and efficient method in comparison with other methods of obtaining a ZnO/Ag nanocomposite. The characteristics of the synthesized product were determined by differential thermal

Abstract In the present work, statistical processing of the electric cardiogram (spectral and bispectral analysis) using the ‘sliding window’ method is proposed and performed. A system for recording and digitizing an electric cardiograms was developed, the output signal of which is fed to a computer. Signal processing is carried out using a system implemented in the LabVIEW environment. It is shown

Abstract The diffraction of an electromagnetic wave from a round hole on an opaque screen is studied when there is no vacuum on the opposite sides of the screen, as is usually considered, but on one side there is a refractive medium and on the other—vacuum. The diffraction peculiarities due to the fact that the medium into which the wave penetrates from the vacuum have a refractive index different

Abstract The pseudobinary HgTe–CdTe, ZnTe–CdTe and HgTe–ZnTe systems were studied and Gibbs energy of mixing were determined at 400–1000 K temperature range. Miscibility gap analysis for CdZnHgTe quaternary material system is also performed by the Gibbs free energy calculations. Quantitative explorations show that there is no immiscibility gap for CdTe–HgTe material system in the mentioned above temperature

Abstract A better theoretical understanding of the atom – surface interactions and of the experimental consequences and applications to a reproducible method for the construction of reliable coated absorption cells is the main scope of our research. In this paper we report on the influence of diode laser intensity and of diode frequency scanning rate on the spectrum of the D2 line of Rb atoms, contained

Abstract The review discusses the results of studies of gas sensors based on zinc oxide. Possibilities and technologies for the manufacture of such sensors are mentioned. ZnO sensors undoped, doped with impurities and carbon nanotubes, as well as sensors based on nanowires and quantum dots are considered. Possibilities of decreasing the operating (working) temperature of heating the working body of

Abstract We describe the application of the phase plane method to analyze the behavior of stationary harmonic plane electromagnetic waves. The phase plane method allows one to describe qualitatively all possible solutions of the Helmholtz nonlinear differential equation without performing a numerical integration. All types of phase portraits for waves in the media with self-action are presented and

Abstract A finite boson representation of fermion operators is obtained. The collective Hamiltonian for a description of the pair excitation is constructed and the collective potential energy is analyzed. The collective modes related to the addition and removal of pair of particles are partitioned off the variety of nuclear degrees of freedom.

Abstract At the RKFM stations in the NRC ‘Kurchatov institute’ the peculiarities of the effect of redistribution of the intensity of the diffracted synchrotron beam in the X-cut quartz crystals at the excitation of transverse resonant ultrasonic vibrations were studied. The dependences of the intensity of the diffracted X-ray beam on the resonant frequency voltage of the signal are obtained, and it

Abstract This work considers the spin-1/2 Heisenberg dimer, the mixed spin-(1/2,1) Heisenberg dimer and their quantum entanglement, particularly, the dependence of the entanglement on the system characteristics and the external magnetic field. The quantum entanglement in this work is determined using two different methods, namely ‘Negativity’ and ‘Concurrence’. The dependence of the corresponding quantities

Abstract Solar photovoltaic-thermal (PVT) hybrid systems have the high potential to be an effective and viable method for producing electricity and thermal energy for low grade heating application. The hybrid system is highly energy efficient with improved electrical efficiency due to cooling of solar cells and gained thermal energy due to heat absorbed by the fluid from the heated cells. Nevertheless

Abstract The features of the energy spectrum and the movement of carriers in one-dimensional asymmetric semiconductor nanosystems are considered. Asymmetric structures with an additional dip in the potential profile in the quantum wells allow one to vary the positions of the dimensionally quantized levels. An additional influence of the external magnetic field leads to non-monotonic dispersion and

Abstract Antireflection layers are an important part of the sensitive elements of high performance single photon detectors. We have obtained amorphous silicon dioxide films by electron-beam sputtering on Al2O3, AlN, Si substrates as well as CeB6, LaB6, and W coatings. The elemental composition, microstructure and surface roughness, as well as optical characteristics of the samples obtained under various

Abstract The spontaneous emission of a spherical semiconductor quantum dot is considered without using the dipole approximation. It is shown that the dipole-forbidden radiation of a shallow potential well with one electron level becomes more intense than the dipole-permitted radiation of a deeper potential well and that the potential deepening makes the dipole approximation closer. It is also shown

Abstract A theoretical study of the spectroscopic properties of the low-phonon LaF3:Er3+ crystals determining their laser capabilities in the mid-infrared wavelength range (2.62–4.97 μm) was carried out. The wave functions of the Stark sublevels of 4S3/2, 4F9/2, 4I9/2, 4I11/2, and 4I13/2 of Er3+ ion are constructed by the LSJM-representation. The line strengths of the indirect electric dipole and magnetic

Abstract The process of photoproduction of a series of radioisotopes from copper nuclei at the bremsstrahlung end-point energies \(E_{\gamma }^{{\max }}\) = 21, 30, and 40 MeV was studied at the AANL (YerPhI) linear electron accelerator. The relative yields of 61Co, 60Co, 58Co, 57Co with respect to the 61Cu are measured; in particular, at \(E_{\gamma }^{{\max }}\) = 40 MeV they are equal to (2.6 ±

Abstract We study the classical multicomponent disordered 3D spin system taking into account the temperature of the medium in the framework of the model of nearest neighbors. The latter allows the 3D problem with a cubic lattice to reduce to the 1D Heisenberg spin glass problem with a random environment. Using the Hamilton equations of motion, a recurrent equation is obtained that connects three spins

Abstract The work is devoted to the problem of analyzing the mechanisms of nonlinear multicomponent diffusion in complex systems. A new method is proposed for determining the stoichiometric coefficients of an elementary act of a complex diffusion process in the framework of a two-cell model of the formal-kinetic description of the cooperative nature of the diffusion jump. To highlight the basic (dominant)

Abstract A dynamic model of a polymer chain is presented, in which the effects of viscoelasticity in the framework of the standard model of the linear body is taken into account. The general solution for the motion equation of the Fourier–Laplace components of the coordinates of the monomers of the polymer chain is obtained. The diffusion behavior of the center of mass of the polymer chain is analyzed

Abstract The nuclear reactions on zinc isotopes leading to the formation of the medical theranostic isotope 67Cu have been investigated. Model calculations were made using the TALYS1.9 code. The results are compared with the published experimental data. The comparison of calculated and experimental data showed a satisfactory agreement in the case of the proton-nuclear reactions. In the case of the

Abstract The paper considers the order-disorder transition in a sequence of two varieties of repeating units. It is shown that the reduced free energy converges to the limit at the chain length of more than 3000. The origination of the fine structure of differential melting curves, the order–disorder transition interval, and the behavior of the fraction of junctions between the ordered and disordered

Abstract The interaction of H2O2 with the stoichiometric surface of (110) SnO2 was studied by first principle methods. Relaxed geometries, adsorption energies, and charge transfer between the molecule and the surface were calculated for several starting configurations of the H2O2 molecule and the SnO2 surface. The most probable adsorption sites and their optimized geometries are presented.

Abstract The sensitivity of gas sensors made of doped SnO2:Co metal oxide for the detection of hydrogen peroxide vapors in the environment was studied using current-voltage, frequency-capacitance, and transient characteristics. Their measurements were carried out at room temperature under the influence of ultraviolet light and without it. It is shown that the influence of ultraviolet rays on the active

Abstract An analytical model is proposed for the study of the effect of surface recombination on the characteristics of a solar cell made of a nanowire with a radial p-n junction formed between its ‘core’ and ‘shell’ with different types of the conductivity. The influence of the surface recombination on such important parameters of the solar cell as the short circuit current, open circuit voltage,

Abstract Doping of a high-temperature Bi(Pb)-2223 superconductor with various additives, which can act as pinning centers and / or accelerate the formation of a superconducting phase, is an effective tool for obtaining Bi(Pb)-2223 samples with improved characteristics. In this paper, we studied the effect of the addition of hexagonal boron nitride (h-BN) on the phase formation and critical transport

Abstract An experimental setup for X-ray on-axis Fresnel holography is suggested. It is based on a three-block Fresnel zone plate interferometer. As a test object, for numerical simulation, a stencil with the text ‘X-RAY OPTICS’ printed on it is considered. Although the quality of the reconstructed image is limited, which should be expected in case of on-axis holography, it is still good enough for

Abstract With the simultaneous presence of positive and negative components both in the permittivity tensor ɛij and in the tensor of magnetic permeability μij, the propagation of an electromagnetic wave in optically homogeneous anisotropic media, and in periodically inhomogeneous media with a spiral structure is considered. It is shown that depending on polarization, such media exhibit the properties

Abstract Results of investigations of metal oxide chemical sensors for the detection of acetone made of tin dioxide were discussed in this review paper. There are several possibilities and technologies to manufacture of such sensors. Pure (without impurities) SnO2 and other metal oxide have low sensitivity to gases at its rather high pre-heating (operation) temperature. Doping of tin dioxide with some

Abstract We study the possibility of application of direct laser writing technique for the fabrication of large-size uniform phase structures in the bulk of the borosilicate glass N-BK7. The morphology and the type of modifications induced by the sub-picosecond (500 fs) pulses are studied depending on the energy dose of irradiation. We show that with moderate focusing and at pulse energies below the

Abstract It is shown that the one-dimensional Coulomb potential well impenetrable in the regularization method becomes partially permeable if the quantum fluctuations are taken into account.

Abstract A ceramic target based on cobalt doped SnO2 metal oxide was synthesized by the solid-phase reaction method. The target was used in the process of high-frequency magnetron sputtering. A thin SnO2:Co film was deposited, which is sensitive to hydrogen peroxide vapor. The current-voltage characteristics of the SnO2:Co sensor were measured in the presence of hydrogen peroxide vapor in the environment

Abstract The aqueous solution with iron nanoparticles investigated by a microwave stripline sensor based on the optimized double quadratic-shape design. Due to real-time near-field electromagnetic interaction between microwaves and sample S11 reflection coefficient of the sensor was changed depending on iron nanoparticles concentration in the aqueous solution at resonant frequencies. In this work we

Abstract The process of the photoemission of one, two, three and four neutrons from the 209Bi nuclei with producing, respectively, 208Bi, 207Bi, 206Bi and 205Bi daughter radioisotopes was investigated at the end-point energies of \(E_{\gamma }^{{\max }}\) = 30 and 40 MeV of bremsstrahlung photons at the AANL (YerPhI) linear electron accelerator. Particularly, for the relative yields of 208Bi/207Bi

Abstract The problem of the propagation of linearly polarized light in an optically inhomogeneous anisotropic media with the amplification (a twist-oriented nematic liquid crystal with the pleochroic dye) is considered theoretically. The existence of an exact analytical solution of the system of complex equations in this geometry is demonstrated to be related to the fact that the deformation of the

Abstract The development of effective anti-reflective coatings of electromagnetic radiation is a necessary basis to solve a wide range of fundamental and applied problems. We studied the conditions for the preparation of lanthanum hexaboride (LaB6) films by electron beam deposition on Al2O3, AlN, ZrO2, Si, and W substrates, and CeB6 and W coatings. The phase and elemental composition, the microstructure