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

Abstract The analysis of the effect of radiation exposure on integrated circuits is carried out. The methods of constructing passively fault tolerant irradiated microcircuits are considered. A review of a method for indirectly measuring the fault tolerance of such microcircuits built using various constant element-by-element redundancy and without redundancy is given.

Abstract A model is proposed that describes the change in the charge state of metal-insulator-semiconductor (MIS) structures and sensors made from it under the conditions of the simultaneous effect of radiation ionization and high-field injection of electrons from a semiconductor. The proposed model takes into account the interaction of injected electrons with holes generated by radiation and high-field

Abstract Single crystals of yttrium orthoaluminate activated with Yb3+ ions (YAlO3:Yb) are of high interest for diode pumped high-power ultrafast lasers emitting in the spectral range around 1 µm. The major parameters of lasers achieved so far can be improved by optimizing the activator concentration and improvement of the structural and optical quality of crystals. One of the problems is occurrence

Abstract The noise characteristics of field-effect transistors based on ZnO: Li films and obtained by the diffusion technology are studied. The results of an experimental study of the noise characteristics of the drain current are presented, namely, the Random Telegraph Signal and 1/f-noise. The spectral density of the drain current noises in the low-frequency range (10–5000 Hz) has a classical 1/f-dependence

Abstract Using the variational method, various types of mixed two-dimensional coupled negative and positive trions in a GaAs strongly oblate ellipsoidal quantum dot in the intermediate quantization mode were investigated. The trial wave function for the positive and negative trions is constructed on the basis of a single-particle wave function obtained in the framework of the adiabatic approximation

Using the finite difference time domain (FDTD) method, we studied the optical properties of black silicon (BSi) layers passivated with the various metal oxides (Al2O3, TiO2, HfO2, and Sc2O3) films, obtained by atomic layer deposition (ALD) method. The results of FDTD modeling indicate an improvement in the antireflection properties of BSi/ALD film structures in the wide spectral range. The necessity

The melting of poly(rA)-poly(rU) and its complexes with the intercalators — methylene blue (MB) and ethidium bromide (EtBr) has been carried out at the ionic strength of the solution 0.02, 0.04, and 0.1 M. It was revealed that this polynucleotide has the non-stable double-stranded structure at the ionic strength of 0.02 M and it becomes more stable at the complex-formation with the mentioned ligands

Using the method of electron beam evaporation, the conductive films of gallium doped (1.6 at%) zinc oxide (GZO) were obtained. As the upper and lower electrodes, silver and glass substrates coated with tin oxide doped with fluorine (FTO) were used, respectively. The films were annealed in air at 350°C for 1 hour. The current-voltage characteristics of the Ag/GZO/FTO structure reveal a linear behavior

In spite of a large amount of the existing experimental data in the region of low-energy proton- and photon-nuclear interactions, new experimental measurements are still needed to gain insight into a number of problems in nuclear physics. Particularly, the stellar nucleo-synthesis, the study of the resonance states of light nuclei, the underlying mechanisms of the (p,n), (p,α) and (γ,p), (γ,n) reactions

The results of the theoretical simulation of an electrolyte-insulator-semiconductor (EIS) biosensor made on a silicon nanowire for the detection of low concentration DNA molecules are presented. The equivalent electrical scheme for the EIS structure is constructed. The phenomenon of charge distribution in a depletion layer of semiconductor is taken into account in computations. The behavior and dependence

X-ray dynamical diffraction Talbot effect in perfect crystals is studied. The effect is analyzed for the case of incident final front wave. Some peculiarities of effect are revealed, expressions for the Talbot effect and exact Talbot effect are found. The results are compared with the ones obtained earlier in a diffracted beam in case of incident infinite front wave.

The possibility of application of a new class of the SFCO sensors (the radiofrequency ‘magnetic-field’ probes) for the non-contact far-field non-destructive scanning of various structures and media is discussed. The prospectivity of their use is shown both for the detection of structural defects of the scanned objects and ‘in-vivo’ investigation of organism tissues and medium.

The process of the DNA sequencing in solid-state nanopores is considered. The theoretical modeling of ionic, thermionic, and tunnel currents for nanopores with the gold electrodes located in bio-liquids has been carried out. It is shown that both the ionic and thermionic currents are several orders of magnitude weaker than the direct tunneling current, which reaches several hundred of nA. The differences

In this paper we present an experimental study of the electron transport in composite samples based on an insulating matrix of polybenzimidazole with graphite nanoparticles as conducting filler. Based on a qualitative analysis of the temperature dependences of electrical resistance obtained for the samples with different filler concentrations, it was established that the electron transport occurred

The hydrothermal microwave method for the synthesis of diopside is developed. The changes in the physicochemical properties under the influence of radiation, which simulate the space conditions and the UV radiation of the Sun on the optical properties of the diopside are investigated. The microwave method enables to manufacture the crystalline CaO·MgO·2SiO2-diopside at lower temperatures (850°C) as

The resistance of a monolayer of complexes of the double-stranded DNA with quantum dots were computed. It was shown that with the non-competitive DNA hybridization and in the presence of monovalent positively charged ligands in the solution, a decrease in resistance occurs as compared to that for uncharged ligands. It is shown that the charged ligands enhance the sensitivity of the DNA chips as compared

A study was made of the physical processes taking place during the generation of a shock wave at the outlet of a nozzle of a gas-generator station, when emitted into the atmosphere at a supersonic velocity of the gas mixture formed in the chamber during the combustion of gas. The investigation of the spectral characteristics of an exciting shock sound wave was made as well as the corresponding computations

The problem of the polarized light propagation in an optically homogeneous anisotropic medium with spatially modulated gyrotropy is considered. The analysis was carried out using a numerical solution of a system of coupled equations obtained in the approximation of geometric optics. For illustrative purposes, the results of numerical analysis are also presented on the Poincare sphere. The resonance

The production of alpha particles in photonuclear reactions on 65Cu, 115In, 92Mo and 207Pb targets in the beam of accelerated electrons with energy of 21 and 40 MeV was studied. The experiments were run on the Linear Electron Accelerator NLA (The Yerevan Physics Institute). The measurement results represent the yields of reactions studied as functions of the mass number of nuclei and the photon energy

The limiting potential model is considered for a spherical quantum dot with three variation parameters–the well depth, external and internal radii. The stationary s-states are computed by way of the exact solution and in the WKB approximation. If the quasiclassical conditions are met, the approximate consideration is applied for the states with l ≠ 0. As a result, the energy values of the lower bound

The continuum elasticity model is applied to investigate quantitatively the growth features and nucleation mechanism of quantum dots, nanopits, and joint QD-nanopits structures in CdZnHgTe quasyternary material system. We have shown that for the CdZnHgTe solid solution deposited on the CdTe substrate, the sign of the critical energy and volume of island is changed at the critical strain of ɛ* = 0.006

The quantum tunneling of a singular potential is modeled, as a rule, by the method of regularization. It proceeds from the intermediate usage of a nonsingular-type preimage of the potential function. In this work, it has been ascertained that the preimages continuously differentiable at the point of singularity does not reproduce the singularity in the problem of quantum tunneling.

The influence of an aluminum compensation filter of complicated form on the signal-tonoise ratio in microtomography of geological cores was investigated. When scanning the core, a compensation filter in the form of an aluminum parallelepiped with a hole approximately equal to the diameter of the core was used. The filter is fixed rigid over the object table, the core is placed in the hole and rotates

The influence of an external electric field on refractive indices of ordinary and extraordinary waves is investigated by means of the method of X-ray interferometry. The decrements of E7 type nematic liquid crystal were calculated for different values of external electric field strength and it was established that with increasing electric field strength the values of decrements of ordinary and extraordinary

The physical principles and advantages of the use of a new class of the SFCO sensors (radio-frequency ‘magnetic-field’ probes) for the investigation of biomedical signals are discussed. The perspectivity of their application for the investigation of dynamic changes of dielectric characteristics of tissues and the medium of the organism is demonstrated. Data related to the registration of the state