East European Journal of Physics

7

Authors: A. V. Glushchenko, M. Y. Kovalevsky

The paper studies the dynamic description of non-equilibrium processes in single-sublattice and multisublattice magnets with the spin s=1. In case of magnets with the spin s=1 and SU(3) symmetry of the exchange interaction, there are eight magnetic integrals of motion: the spin and the quadrupole matrix. If there are multiple sublattices, the number of additional magnetic quantities characterizing the state increases to sixteen. The presence of the Casimir invariants makes it possible to reduce the number of independent degrees of freedom. Exchange energy models are presented in terms of Casimir invariants corresponding to SO(3) or SU(3) symmetry groups for all four types of magnetic degrees of freedom. For the homogeneous part of the exchange energy, we have found conditions for the existence of local minima, which correspond to equilibrium values of the magnet. Along with the known waves (quadrupole and Goldstone – for the spin nematic), spectra of collective excitations that take into account ferro-quadrupole excitation, quadro-nematic, quadro- antiferromagnetic, and antiferro-nematic waves excitation, are also obtained. In the case of many-sublattice magnetic systems, we have shown that the selected form of the homogeneous energy model allows us to find possible magnetic orderings and to investigate them for stability.

8

Authors: D. S. Bondar, I. P. Levchuk, V. I. Maslov, I. N. Onishchenko

Earlier, the authors found a mechanism for the sequence of short relativistic electron bunches, which leads to resonant excitation of the wakefield, even if the repetition frequency of bunches differs from the plasma frequency. In this case, the synchronization of frequencies is restored due to defocusing of the bunches which get into the bad phases with respect to the plasma wave. However, in this case, the bunches are lost, which as a result of this do not participate in the excitation of the wakefield. In this paper, numerical simulation was used to study the dynamics of electron bunches and the excitation of the wakefield in a magnetized plasma by a long sequence of short bunches of relativistic electrons. When a magnetic field is used, the defocussed bunches return to the region of interaction with the field after a certain time. In this case, the electrons of the bunches, returning to the necessary phases of the field, participate in the excitation of the wakefield. Also, the use of a magnetic field leads to an increase of the frequency of the excited wave relative to the repetition frequency of bunches. The latter increases the time for maintaining the resonance and, consequently, leads to an increase of the amplitude of the excited wakefield.

8

Authors: O. Ivashtenko

The greenhouse is a tool for the accumulation of solar energy and its conversion into heat. The article investigates the heating of the greenhouse caused by the difference in the transmissivity of glass in different wavelength ranges. Firstly, some facts from the history of the phenomenon investigation are presented. The principle of greenhouse operation is considered. Then we explain the greenhouse effect theoretically using a simplified model, and carry out an experiment. In our experiment, the heating of a 1 m² surface greenhouse model has been observed. The temperature changes have been registered, and the ultimate temperature has been measured. Further, a model of an ideal greenhouse is proposed in order to reduce heat losses. The main principles and generalizations of the greenhouse effect are discussed. The role of the glass transmission spectrum, which is one of the most important factors determining the maximum temperature is investigated. Maximum temperatures for different spectra are compared. We calculate theoretically the maximum temperature, which can be achieved in an ideal greenhouse under ideal conditions. Then we consider other factors limiting temperature growth. Finally, the ways of application of the greenhouse effect in the development of solar collectors are indicated.

10

Authors: U. Tarabara, K. Vus, S. Girnyk, N. Kamneva, O. Lavryk, M. Mikhailyuta, V. Trusova, G. Gorbenko

The influence of the lysozyme and serum albumin in their native and amyloid forms on the electrokinetic behavior of the negatively charged uni- and multilamellar liposomes from the zwitterionic lipid phosphatidylcholine and anionic lipid cardiolipin has been investigated using the microelectrophoresis technique. The zeta - potential, the surface electrostatic potential and surface charge density of the lipid vesicles have been determined upon varying the lipid-to-protein molar ratio. The complex dependencies of the electrophoretic mobility on the protein concentration and reversal of the surface charge observed for the multilamellar vesicles have been explained by the multilayer protein adsorption on the liposomal surface. It has been found that the native and fibrillar proteins differ in their ability to modify the charge state of the model membranes.

13

Authors: V. B. Ivanskyi, O. N. Letuchyy, А. N. Orobinskyi, H. V. Siroko

The energy and pulse height spectrum of PuBe and 238PuBe neutron sources are measured without taking into account scattered radiation, taking into account this radiation (without the shadow cone) and own scattered radiation from these sources (with a shadow cone) using a NEMUS spectrometer on Bonner spheres with 3He -counter. An analytical solution of the likelihood function equation is given, taking into account the fact that the counting rate of pulses obeys the chi-square distribution used to estimate the variances, the discrete Poisson distribution, and the normal distribution, using the Bayes theorem and the Lagrange multiplier method. The values of the main characteristics of neutron radiation are measured: neutron flux density, ambient dose rate equivalent, individual dose rate equivalent and average neutron radiation energy. Extensive uncertainties were obtained in the measurement of these characteristics with a confidence level of 0.95. Calculation of energy spectrum, basic characteristics of neutron radiation and extended uncertainties is performed by the MAXED (maximum entropy and deconvolution) method using the UMG_3.3 software.

5

Authors: A. V. Levenets, I. V. Kolodiy, N. V. Berezhnaya, Y. S. Lipovskaya

The structure and mechanical properties of high-entropy CoCrFeMnNi (equiatomic) and Co20Cr26Fe20Mn20Ni14 alloys, which differ significantly in the stacking-fault energy, are studied. The structure of the alloys was investigated in three states – as-cast, after homogenizing annealing at T = 1000 °C for 24h and after annealing at T = 850 °C. It was found that in the cast state and after homogenizing annealing at 1000 °C both alloys are single-phase solid solutions with a FCC lattice. Annealing at 850 °C preserves the single-phase state in the equiatomic CoCrFeMnNi alloy, but leads to the appearance of a σ-phase in the Co20Cr26Fe20Mn20Ni14 alloy. The mechanical properties of these alloys were studied in a single-phase state by uniaxial compression tests and hardness measurements. It was discovered, that both alloys in a single-phase state had high plasticity and tendency to force strain hardening. The behavior of hardening coefficients in the area of true strains e = 0.05 – 0.17 vary considerably. This may be due to a significant difference in the stacking-fault energy of the investigated alloys. As a result, in Co20Cr26Fe20Mn20Ni14 alloy along with dislocation deformation mechanism there is a high probability of implementation the twinning mechanism.

8

Authors: V. N. Bondarenko, A. V. Goncharov, V. I. Sukhostavets, T. Kh. Salikhov, A. A. Abdurahmonov

A technique for infrared thermometry remote monitoring of temperature of area of a polymer film under ion irradiation is described. Calculation part of the technique takes into account the case when the irradiated area is significantly smaller than the instrument field of view. Temperature measurements were carried out with 20 μm polyimide films irradiated by 1000 to 1600 keV protons, with 1…5 μA/cm2 current density. A model for calculation of temperature depth distribution in the irradiated film is developed. The model is also applicable for the case of ion irradiation in gaseous atmosphere, and takes into account temperature dependence of the polymer substance thermal conductivity, of the emissivity coefficient, and of the convective heat transfer coefficient. The calculated data are compared with the temperature measurements.

10

Authors: V. M. Kuklin, D. N. Litvinov, S. M. Sevidov, A. E. Sporov

In this paper, the self-consistent model was considered, consisting of a system of oscillators, the coupling between them was assumed to be integral (due to the fields formed as a result of their co-radiation). With the help of this model, the features of synchronization by waves of finite amplitude of a system of oscillators were refined, the initial phase values of which are random. The effect of nonlinearity, in particular, due to the change in the mass of the oscillator due to relativistic effects, was taken into account. It was shown that the nonlinearity does not violate the nature of the energy exchange between the wave and the oscillator system, leading only to a slight decrease in the efficiency of such an exchange.

24

Authors: M. I. Kopp, A. V. Tur, V. V. Yanovsky

We found a new large-scale instability, which arises in the rotating conductive fluid with small-scale turbulence. Turbulence is generated by small-scale external force with a low Reynolds number. The theory is built simply by the method of multiscale asymptotic expansions. Nonlinear equations for vortex and magnetic perturbations obtained in the third order for small Reynolds number. It is shown that the combined effects of the Coriolis force and the small external forces in a rotating conducting fluid possible large-scale instability. The large-scale increments of the instability, correspond to generation as the vortex and magnetic disturbances. This type of instability is classified as hydrodynamic and MHD alpha-effect. We studied the stationary regimes of nonlinear equations of magneto-vortex dynamo. In the limit of weakly conducting fluid found stationary solutions in the form of helical kinks. In the limit of high conductivity fluid was obtained stationary solutions in the form of nonlinear periodic waves and kinks.

4-21

Authors: Yu.M. Poluektov, A.A. Soroka

For the ideal Fermi gas that fills a quantum well confined by two parallel planes, there are calculated the thermodynamic characteristics in general form for arbitrary temperatures, namely: the thermodynamic potential, energy, entropy, equations of state, heat capacities and compressibilities. The distance between planes is considered as an additional thermodynamic variable. Owing to the anisotropy, the pressure of the Fermi gas along and transverse to the planes is different, so that the system is characterized by two equations of state and a set of different heat capacities. Limiting cases of low and high temperatures are considered. The temperature dependencies of the entropy and heat capacities at low temperatures remain linear, just as in the volume case, and their dependencies on the chemical potential and density undergo jumps at the beginning of the filling of new discrete levels. It is shown that the behavior of thermodynamic quantities with the distance between plates can be either oscillating or monotonic, depending on what quantity is assumed to be fixed: the volume or surface density. For high temperatures the corrections to thermodynamic quantities are obtained, which are proportional to the ratio of the thermal de Broglie wavelength to the distance between planes.

34-42

Authors: Yu.V. Kulish

The hypothesis on quark nature of the leptons is proposed. Leptons are compacted q3 -systems. It ensures the equality of modules for the electric charges of the proton and the electron. The classification of particles based on the U(Nf,g)×SU(3,c)×SU(4,fs)×O(3) -group is proposed at arbitrary quantity Nf of the quark generations. The U(Nf,g)-group corresponds to the quark generations, the SU(3,c) -group describes the color variables, the SU(4,fs) -group corresponds to the variables in the spin (s) and flavor (f) spaces, and the O(3) -group describes the orbital excitations of quarks. In consequence of the Pauli principle leptons consist of antiquarks from 3 different generations. Minimal quantity of leptons with definite electric charge equal 20. Excited double charged l−− -leptons and l + + -antileptons with the 1 2 Jp=(1^+)/2) Jp=(1^-)/2) are predicted, respectively. They can be resonances in e−π − ,e−K− ,e+π + ,e+K+ , μ −π − ,μ −K− ,μ +π + ,μ +K+ -systems.

51-59

Authors: B.V. Borts, I.V. Tkachenko, V.I. Tkachenko

Model of Earth charge resonant oscillations excitations based on Tesla experiment, was offered. Solutions of d'Alembert wave equations for electric and magnetic potentials of the charged perfectly conductive sphere were found. Graphic analyses of perturbed potential distribution on the Earth surface was provided. It was shown that obtained solution provides adequate description of Tesla experiment on wireless transfer of electricity conducted in Colorado Springs in 1899 – 1900. In the very low-frequency area of the electro-magnetic oscillations spectrum it was offered to consider the Earth as capacitors battery, consisting of two put one into another perfectly conductive spheres, between which thin dielectric layers is placed. Own oscillation frequencies of the Earth charge were determined in this area. It was shown that these frequencies most precisely correspond to experimentally measured Schumann resonances.

66-71

Authors: V.I. Tyutyunnikov

The spectral parameters ultrafine particles Zn2SiO4-Mn, precipitated on the substrate in a magnetic or electric field have been investigated. For getting fine particles industrial phosphor K-60 (Zn2SiO4-Mn) was used. Luminescence spectra were obtained on a sample when exposed to ultraviolet light or a beam of charged oxygen ions. When excited by ultraviolet spectral characteristics have difference for samples with different dimensions of the crystals. As for the industrial design luminescence spectrum had a band with λmaх = 521 nm, and for the ultrafine crystals willemite spectral band had λmax = 550 nm. Analysis ionoluminescence spectra showed that the reduction of crystal size Zn2SiO4-Mn not affect the spectral characteristics of the excitation beam with low energy oxygen ions. The luminescence spectrum when exposed to low-energy ions (1-3 KeV) has a band with λmax = 521 nm and a half-width Δλ = 41 nm. When measuring the width of the forbidden zone has been established bandgap dependence on the size of the phosphor crystals. The width of the band gap increases with decreasing crystal size to nanoscale sizes. A significant effect was obtained when deposited on a substrate in the nanoscale crystal magnetic or electric field. As for the industrial design the bandgap was 4.16 eV, and for the besieged in the magnetic and electric field of 4.27, 4.29 eV, respectively.

78-82

Authors: V.G. Kirichenko, A.A. Yampolskiy

Monatomic surface layers of graphite were simulated on the basis of experimental data, which was obtained by scanning tunneling electron microscopy of atomically smooth surface of graphite. Values of relative deviation of the electron density were defined in the direction perpendicular to the plane of the layer. Increase in the degree of waviness layer to 2 nm are observed by increasing of linear dimensions under review graphite surface area of up to 25 nm. These results are confirmed by the data available for the graphene layers, which is caused by waviness defect. Indeed, defects such as vacancies and interstitial carbon atom are formed by increasing the number of cells to the surface layer up to 20.

4-24

Authors: S.V. Lytovchenko

The overview presents a historic retrospective and current state of research of structure, properties and application of hightemperature silicide materials in science and engineering. These materials, particularly construction and functional materials based on or involving silicide refractory metals, are a most important alternative class of materials which adequately complete with special alloys, intermetallic metals, and ceramics that are traditionally used at high (above 15000C) temperatures in oxidizing and other aggressive environments. The paper analyzes the data available on constitutional diagrams, particularly on molybdenum-silicon and tungsten-silicon systems. Also, it shows differences in descriptions of diagrams given by different authors and considers some crystallochemical and physical properties of some high-temperature silicides. The paper reviews areas of application of high-temperature silicide materials of various types (layered and multiple-phase composites, consolidated powders, film structure, three-dimensional materials), and presents details of the challenges encountered in the process of creation and application of high-temperature protecting silicide coatings, as well as possible ways to improve their performance. It is noted that lack of unified approach to presentation and correlation of research results as well as to description of real performance of materials is a substantial problem in creating new high-temperature silicide materials.

35-46

Authors: Yu.M. Poluektov

Self-consistent approach for interacting phonons description in lattice, which generalizes Debye model, is proposed. Notion of “selfconsistent” phonons is introduced, speed of which depends on temperature and is determined from non-linear equation. Debye energy is also a function of temperature in this approach. Thermodynamics of “self- consistent” phonon gas is constructed. It is shown, that at low temperatures there is a correction propotional to the seventh power of temperature to the cubic law of specific heat dependence on temperature. This may be one of the reasons why cubic law for specific heat is observed only at rather low temperatures. At high temperatures the theory predicts linear deviation from Dulong-Petit law, which is observed experimentally.

64-72

Authors: V.I. Kasilov, S.P. Gokov, A.N. Dovbnya, S.A. Kalenik, K.S. Kokhnyuk, S.S. Kochetov, A.A. Khomich, O.A. Shopen

In this paper, to obtain streams of thermal and epithermal neutrons are used delayed neutrons emitted from the target with a fissile material. The target preliminarily activated with help of electron beam from linear accelerator with an energy of 20 MeV and a power of 9 Watts. At the same time to obtain a stream of thermal as well as epithermal neutron density 6 10-5 n / (cm 2 s) The results of experiment are presented where half-decay curves have been measured of emitting delayed neutrons radioactive nuclei produced in the fission process. It has been shown that the activated target, which contains the fissile material, presents a compact small size source of delayed neutrons. It can be delivered to the formator where thermal and epithermal neutrons are formed during a certain time period with help of the moderator, absorber and collimator. Then this target is moved to the activator being replaced with another target. Thus, pulsed neutron flux is produced. The duration of neutron pulse corresponds to the presence time of the activated target in the formator, and time interval between pulses is determined by the delivery time of the target from the activator to the formator. Given that the yield of neutrons from the target is directly proportional to the power of the beam of accelerated electrons, shows that the beam power of 1.5 - 3 kW, the flux density of thermal and epithermal neutrons can reach the values of (2-3) 109 n / (cm2 s). Such a neutron beam can be used in nuclear medicine, in particular, in neutron capture therapy of oncologic diseases.

84-87

Authors: D.G. Malykhin

A calculation of X-ray diffraction on the dislocation structure of polycrystalline materials with the biaxial anisotropy of the crystal lattice has been carried out. The task was reduced to definition of the field of lattice distortion in this neighborhood applied to edge dislocations of the «c» type in condition of anisotropy of elastic modules of a crystal. As a result of general solution of this task, a parameter of spatial anisotropy of the distortion field was defined from elastic modules and further included into tensors of transformation of both initial isotropic model of this field and its coordinates. According to this principle a modified mathematical model of the field of elastic atomic displacements in the neighborhood of an edge dislocation has been built. The final result shows that this anisotropy entirely reflects onto dislocation specific parameters of distortion that can be obtained by an XRD method for determination dislocation distributions and density. It is noted that for hcp metals widely used, accounting of this anisotropy would be reduced to small corrections of parameters.

92-100

Authors: G.G. Lesnyakov, A.N. Shapoval

also, the electron beam injection in the additional toroidal magnetic field (16 coils, making up 60% to 76% of the total toroidal field). In the stationary toroidal magnetic field, the turns of the electron beam have been visualized by scanning the poloidal vacuum chamber cross-section with a luminescent rod. The measurements have made it possible to determine a decrease in the ratio of stray environment vertical magnetic fields to toroidal-coil magnetic field down to z/BT ≈ 1×10-3 at magnetic fields ВТ = 0.0225 - 0.15 T, and also, to estimate the prospect of the ratio decrease to z/BT ≈ 1×10-4 as the toroidal magnetic field increases up to ВТ ≥ 0.45 Т.

4-14

Authors: M.Y. El-Bakry, E.A. El-Dahshan, A. Radi, M. Tantawy, M.A. Moussa

Multiparticle production mechanism is one of the most phenomena that the high-energy physics concerns. In this work, the evolutionary genetic algorithm (GA) is used to optimize the parameters of the back-propagation neural networks (BPNN). The hybrid evolutionary-neuro model (GA-BPNN) was trained to simulate the rapidity distribution (1/N *(dN/dY) of positive and negative pions for p − Au, p − Ag and p −Mg interactions at lab momentum Lab (P ) =100 GeV/c. Also, for total charged, positive and negative pions for p − Ar, p − Xe interactions at Lab P = 200 GeV/c. Finally, total charged particles for p − Pb collision at center-of-mass energy ( s ) = 5.02 TeV are simulated. An efficient ANN network with different connection parameters (weights and biases) have been designed by the GA to calculate and predict the rapidity distribution as a function of the lab momentum Lab (P ) , mass number (A) and the number of particles per unit solid angle (Y). Our simulated results have been compared with the experimental data and the matching has been clearly found. It is indicated that the developed GA-BPNN model for rapidity distribution was more successful.

26-31

Authors: S.I. Derevianko, A.K. Kuzniak, Ju.A. Liashenko, I.O. Shmatko, O.A. Shmatko

The mathematical analysis of influence of additives of the third component (Cr, Mn, Fe, Co, Ni, Ga, Zr, In, Sn) on quantities of energies of a segregation of impurities in volume and on boundaries of grains of alloy Cu-4,35 at. % Ti is made during aging on the cellular mechanism. Calculation of enthalpies of a segregation is spent with the account of energies of interatomic and elastic interaction of atoms of a different grade. Effects of experimental researches testify, in particular, to effective accelerating influence Ni on development of cellular decay in alloy Cu-4,35 ат. % Ti and essential inhibiting action of the given process by an additive Co. On the basis of modelling calculations of enthalpies of mixture in volume and on boundaries of grains it is erected that for the specified additives distinctions in quantities of an enthalpy of mixture in volume of grains appear considerable. The carried out analysis can be taken as a principle build-ups of model of a dynamic segregation and its influence on velocity of cellular decay in threefold metal systems.

41-48

Authors: D.V. Kutnii, A.V. Medvediev, S.A. Vanzha

The work presents the results of method development for matrix effects correction in X-ray fluorescence measurements of Ti, Mn, Fe and U concentrations in the silicate-type uranium ore samples using wavelength dispersive XRF spectrometer S 8 Tiger (Bruker AXS GmbH, Germany). Comparison of the results obtained using standard software package Spectra Plus of the spectrometer and normalized to intensity of characteristic line of primary radiation, incoherently scattered by sample, was carried out. It is shown that for the investigated elements during X-ray fluorescent measurements of their concentrations, in addition to intensity normalization, it is necessary to use additional analytical correction. The use of this method to calculate the corrected concentrations of TiO2, MnO, Fe2O3 and U3O8 allows to decrease the relative error of measurements up to < 5 % within the range of concentrations 0.1…4 mas. % and up to ≤ 7.5 % within the range of concentrations 0.04…0.06 mas. %.

54-60

Authors: D.G. Malykhin

Results of a precise calculation of X-ray diffraction on distorted edge-dislocation neighborhood in crystals are represented. Calculation of lattice sums of diffraction has been carried out with adherence to the classical scheme. So unlike to the previous approach, finite-differential distances of atomic pairs of diffraction were immediately taken into account here. The statistical form of their representation was used. Obtained results are compared with previous those based on identification of X-ray profiles with statistical strain distribution. It was found that accuracy of the previous result is sufficient for analyses of the dislocation structure with moderate inhomogeneity.

65-69

Authors: I.I. Yakimenko, N.G. Styervoyedov, A.F. Shchus, G.M. Onyshchenko

The paper shows the possibility of determining of the radon by the radiometer on a base of multi-channel time analyzer of beta – decay products of radon. The radiometer consist of an electrostatic aerosol collector combined with the air intake, Geiger-Muller counter for detection of beta particles and multi-channel time analyzer. Accumulation time of aerosol sample takes up to 20 min, the time data processing is done by the radiometer about 5 hours. The data processing is at off-line mode using the computer decomposition process of decay spectrum.