East European Journal of Physics

5-12

Authors: Oryna Ivashtenko

The paper considers a cosmographical approach to analyze cosmological models. Cosmography is a method to describe the kinematics of the cosmological expansion based only on the cosmological principle. We consider a method of treating free parameters of a cosmological model in terms of the directly observable cosmographic values related to the time-derivatives of the Hubble parameter (deceleration, jerk, snap). The method is applied to analyze two cosmological models involving the time-dependence of the cosmological constant in the form Λ(t)→Λ(H) when this approach is especially efficient. Both models interpret the dark energy in the form of the cosmological constant Λ as energy of physical vacuum, which is currently the most supported treatment. The first one means Λ being proportional to the Hubble parameter, and the second one involves a constant and a quadratic term. As a result, the free parameters of both models are expressed in terms of the currently observed values of the Hubble parameter, deceleration, and jerk. The obtained expressions for model parameters are exact, as the method does not involve any additional assumptions. Furthermore, it leads to deal with algebraic equations instead of differential ones. After this procedure, solutions of the evolution equations are obtained in the form of the time-dependence of the Hubble parameter. The obtained model parameters are substituted to the solutions, which are analyzed for a typical range of cosmographic scalars taken from recent observations. Finally, the proposed approach is used to eliminate free parameters from both models and to obtain constraints for the directly observable cosmographic values that can be tested to correspond to present observations data. For the considered cases, such constraints are received respectively for the jerk and the snap parameters with respect to the deceleration. The constraint for the linear model is compared with current observational value ranges for the deceleration and the jerk parameters.

22-29

Authors: U. Tarabara1, O. Ryzhova, K. Vus, A. Kurutos, V. Trusova, G. Gorbenko, N. Gadjev, T. Deligeorgiev

The applicability of the novel cyanine dye AK 3-1 to the detection and characterization of pathogenic protein aggregates, amyloid fibrils, was tested using the absorption spectroscopy technique. In an organic solvent dimethyl sulfoxide (DMSO), absorption spectra of AK3-1 exhibits vibrational structure with the relative intensity of 0-0 sub-band being higher than that for the 0-1 sub-band. In an aqueous phase the dye absorption band undergoes hypsochromic shift relative to DMSO due to H-aggregation of the dye. The interaction of AK3-1 with the native and fibrillar insulin was followed by the decrease of monomer band and the enhancement of H-dimer band. To evaluate the relative contributions of the monomeric and aggregated forms, the absorption spectra of the protein-bound dye were deconvoluted using the asymmetric log-normal (LN) function. The analysis of the set of fitting parameters provides evidence for the protein-induced AK3-1 self-association into the head-to-head dimers, with the magnitude of this effect being much more pronounced for fibrillar protein form. The molecular docking studies showed that the AK3-1 monomer tends to associate with the specific arrangement of side chains in the β-sheet formed by L17 leucine residues (of the insulin B-chain), located on the dry steric zipper interface of the fibril, while the dye dimers form stable complexes with the amyloid groove formed by the residues Q15 and E17 of the A-chain, and located on the wet interface of the fibril. The latter binding site is more easily accessible and is additionally stabilized by the electrostatic interactions between the positively charged dye and the E17 residue. This binding mode seems to be prevailing over that for the AK3-1 monomers. Based on the results obtained, AK3-1 may be recommended as a prospective amyloid marker complementary to the classical amyloid reporters Thioflavin T and Congo Red.

40-47

Authors: K. Lobach, S. Sayenko, V. Shkuropatenko, V. Voyevodin, A. Zykova, E. Bereznyak, Y. Hodyreva, S. Bykanov, A. Bykov, L. Tovazhnyanskyy

The interest in silicon carbide (SiC-based) ceramics and composites as matrix material for nuclear waste immobilization is grown up. Long-term chemical durability and radiation resistance of SiC are important factors for radionuclides immobilization. Advantages of SiC-based ceramics as structural materials in nuclear applications are the high-temperature properties, high density and reduced neutron activation. The use of radiation resistant materials is a strong requirement for safe and environmentally beneficial energy system. The SiC ceramics stability under irradiation for temperatures up to 1273 K is also very important for nuclear power applications. The SiC matrices doped by additives of Cr, Si were fabricated using High Speed Hot Pressing Method. Additives content was in the range from 0.5 to 3 wt %. Microstructural characteristics of silicon carbide ceramics were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and infra-red spectroscopy (IR) methods. The results of microcracking under indentation conditions were revealed the lack of cracks in the SiC ceramics with Cr additives before and after irradiation process. In addition, it was demonstrated that samples of SiC with alloying additives Cr and Si possess high mechanical parameters under γ-irradiation process. The strength of ceramics increases with the uniform and fine-grained structure formation. The modification of phase composition and mechanical properties of the SiC ceramics with Cr and Si additives under γ-irradiation were analyzed for further development of radiation resistant and matrix materials for radioactive wastes immobilization.

58-68

Authors: I.G. Marchenko, I.I. Marchenko, V.I. Tkachenko

Recently, both the experimental data and the data of theoretical research appeared stating that the diffusion coefficient shows nonmonotonic behavior with temperature. The motion of Brownian particles in the space periodic structures is an example of the systems with abnormal temperature dependence of the diffusion. The aim of the work was to study the change in the temperature dependence of the diffusion coefficient with a change in friction, both in underdamp and overdamped systems. This scientific paper studies the diffusion of particles in tilted spatial-periodic potentials in a wide temperature range. It is shown that in both underdempted and overdamped systems, the diffusion coefficient reaches a maximum value for a certain value of an external force, the value of which depends on the value of the friction coefficient. However, in systems with low and high friction, the temperature dependence of the diffusion coefficient differs. It was established that the systems with a low friction level γ’ show temperature abnormal diffusion (TAD) at which the diffusion coefficient D is increased with a decrease in temperature. At the same time, the diffusion is enhanced at high γ values with the rise in temperature. This scientific paper studies the transition procedure from the exponential dependence of TAD to the ordinary power temperature dependence with an increase in γ’. It was shown that the energy hump that separates “running” solutions and “localized” solutions is decreased with an increase in the friction coefficient and it vanishes at . Simultaneously with a decrease in ε, the temperature interval of the TAD also narrows. It was established that the temperature-limited TAD domain appears in the region of intermediate values of the friction coefficient. In a specified force range the diffusion coefficient is first increased with a decrease in temperature and then it begins to decrease again. The diagrams of existence of such domains have been constructed. The results obtained opens up prospects for the creation of new technologies for managing diffusion processes. This is of great importance for the production of nanomaterials with a given structure, the creation of surface nanostructures, etc.

77-86

Authors: А.N. Dovbnya, R.N. Dronov, V.A. Kushnir, V.V. Mitrochenko, S.A. Perezhogin, L.I. Selivanov, V.A. Shevchenko, B.I. Shramenko

The results of the photonuclear production of 11C and 18F isotopes in various target-matrices are summarized. The studies were performed using linear electron accelerators of the R&DE "Accelerator" NSC KIPT NAS of Ukraine in the energy range 10 -40 MeV to determine the possibilities of obtaining the maximum achievable activity levels of 11C isotopes, and 18F with a view to planning further developments on the creation of radiopharmaceutical for these nuclear isotopes. In the framework of the above approach, we measured the activity levels of the 18F which is transferred to the surrounding aquatic environment during irradiation of targets-matrices of fluoroplastic (C2F4) with bremsstrahlung flux. The release of the 18F isotope into the aquatic environment under the most favorable conditions (in terms of energy and average beam current) was 3.6% of the target-matrices activity - 40 MBq/g, which is a very low figure. Despite the encouraging value of the specific activity of 18F isotope in lithium fluoride (LiF) -77 MBq/g target–matrices and hydrofluoric acid (HF) - close to 100 MBq/g, the process of extracting 18F from C2F4, LiF and HF as basis of the radiopharmaceutical is not sufficiently effective and brings into question the feasibility of such a methodology for producing 18F isotope for further use. More efficient was the production of the 11C isotope in the irradiated target-matrix of the standard therapeutic form "glucose monohydrate" (glucose). It was shown that, as a result of irradiation of glucose with a gamma-quanta beam, it is possible to “label” glucose with the 11C isotope, which is formed as a result of the photonuclear reaction 12C(γ, n)11C at the 12C nucleus, which is part of the glucose molecule C6H12O6 H2O. Irradiated sample of glucose dissolved in a given volume of solvent (distilled water) will be ready for use radiopharmaceutical "Glucose, 11C". It has been shown that the “photonuclear method” provides for obtaining the “Glucose, 11C” radiopharmaceutical complex with total activity necessary for performing PET diagnostics. The radiopharmaceutical "Glucose, 11C" by the time of its use has 100% radionuclide purity. “Glucose, 11C” obtained in this way was produced for the first time. The choice of the optimal design of a water-cooled target station, providing a moderate (in terms of heat loads) mode of irradiation of a capsule filled with glucose tablets, is discussed. Using the program “SolidWorks FlowSimulation 2011”, the quantitative characteristics of the flow rates of water flowing around the glucose capsule and the converter are calculated.

93-97

Authors: R. Skiba, І. Mysiura, O. Kalantaryan, V. Zhurenko, S. Kononenko

The paper presents the results of an experimental study of Poleskiy amber luminescence excited by narrow band UV radiation (7 nm) at the wavelength range of 310–410 nm with step of 10 nm. The purpose of the study was to determine the relation between an excitation of two luminescence centers, which we found earlier as a result of the mathematical treatment of the spectra obtained during a cycle of experiments on the photo- and X-ray luminescence of amber from the Poleskiy deposit. It was shown that for various samples the spectra of light excited by UV irradiation had a wide band of luminescence with some differences both in shapes and maximum positions. Increasing the exciting UV radiation wavelength, the monotonic displacement of the spectrum maximum position (from 2.62 to 2.5 eV) and the decrease of the full width at half maximum (from 0.92 to 0.62 eV) were observed. To analyze the spectra, we applied the mathematical treatment procedure that we successfully used earlier, namely fitting of experimental curves with Gaussian functions. It was demonstrated that the shape of our spectra could be with high accuracy deconvoluted by two peaks well described by Gaussian functions. The observed differences in shapes of the spectra can be explained by changes in the amplitudes of the two peaks with centers at 2.5 and 2.95 eV. The photoluminescence experiments with excitation by a narrow band UV radiation showed that light generation at wavelengths corresponding to these centers varied significantly by the change of primary UV radiation wavelength. The most intense excitation of the 2.5 eV band (496 nm) corresponds to the UV radiation wavelength of 384 nm (3.23 eV), and for the 2.95 eV band (420 nm) – 287.5 nm (4.32) eV. This led to the conclusion about an independent nature of the excitation of these centers. Spectrum changes can be explained by the different excitation efficiency of both centers.

103-105

Authors: M.A. Grado-Caffaro, M. Grado-Caffaro

It is well-known that II-VI compounds occupy a very relevant place in the whole context of semiconductors. In particular, II-VI semiconductor and isolating or quasi-isolating oxides play an important role. Among these materials, we can mention zinc oxide and cadmium oxide. These oxides, which are transparent (at least in the visible range), are suitable for a number of optoelectronics applications. In this respect, let us consider solar cells; indeed, the above oxides serve as antireflection coatings for these cells. Cadmium oxide, doped or undoped, despite it is hazardous to manipulate, is certainly very interesting for the aforementioned optoelectronics applications. On the other hand, many aspects of this oxide may be regarded from the experimental and theoretical standpoints. In relation to the experimental side, several techniques are currently used to produce cadmium oxide. Among these experimental methods, one can mention metal evaporation, sputtering over a glass substrate, and laser deposition. Perhaps, laser deposition is more advanced and promising than the other techniques. In addition, the fact that laser is involved in this type of deposition gives rise to that the main aspects of the physics and chemistry of cadmium oxide are, say, enhanced. Really, the physics and chemistry of cadmium oxide constitute a significant issue. In order to examine accurately the principal physical mechanisms underlying the formation of cadmium oxide by laser deposition, an in-depth theoretical nonlinear study upon the above formation is presented in this article. As a matter of fact, taking into account that the molecules ( , , ) in the chemical reaction which gives CdO are diatomic, the Morse potential is assumed to act upon the inter-nuclear axis of the molecules which, consequently, behave as quantum anharmonic (nonlinear) oscillators. In fact, associated with the corresponding chemical reaction, inelastic collision between a cadmium molecule and an oxygen one is considered to give rise to two molecules of cadmium oxide. We analyze carefully this collision from the quantum-mechanical point of view (we recall that the molecules in question behave as quantum anharmonic oscillators). From this molecular collision, energy loss is produced due to the laser action. The energy loss is calculated and, from this result, we deduce a mathematical condition to be obeyed for the size of anharmonicity by using a suitable parameter.

4-12

Authors: Yu.M. Poluektov

When analyzing thermodynamic and kinetic properties of crystals whose anisotropy is not large and the considered effects do not relate to the existence of singled-out directions in crystals, one may use a more simple model of an isotropic medium with a good accuracy, after having chosen its parameters in an optimal way. Based on the quantum mechanical description it is shown that the method of approximation of the moduli of elasticity of a crystal by the model of an isotropic medium, proposed earlier in [2], follows from the requirement of the minimal difference between the free energies of a crystal and an approximating isotropic medium. The two-parametric Debye model is formulated, which, in contrast to the standard model where the average speed of phonons is introduced, takes into account the existence in an isotropic medium of both longitudinal and transverse phonons. The proposed model contains, except the Debye energy, an additional dimensionless parameter and, consequently, the law of corresponding states for the heat capacity being characteristic of the standard model does not hold. With taking account of the two phonon branches the structure of the density of phonon states proves to be more complex as compared to the standard model and has a singularity that resembles Van Hove singularities in real crystals. As an example, an application of the two-parametric Debye theory to such crystals of the cubic system as tungsten, copper, lead is considered. It is shown that the calculation of the low-temperature heat capacity of these crystals by means of the approximated moduli of elasticity within the framework of the two-parametric model leads to a considerably better agreement with experiment than in the case of the standard Debye model.

24-31

Authors: V.M. Svishch

At consideration of the theory of the Michelson’s experiment and conducting experiments on its scheme of dividing the amplitude of the light flux as an informative parameter, the difference in the lengths of the paths of the transverse and longitudinal rays of the light flux is used by measuring the shift of the interference pattern of the transverse and longitudinal rays. The significance of the other circuit parameters in determining the influence of the Earth's speed with the help of Michelson interferometers was not considered. The analysis of the parameters of the schemes of Michelson interferometers with the division of both the wave front amplitude and its wave front in the reference system associated with the interferometer is carried out in order to determine the influence of the interferometer speed on them. As a result of the analysis of the scheme with the division of amplitude, a linear dependence of the changes in frequency, the width of the reflected rays on the ratio of the device speed to the speed of light in interferometers. In the Michelson interferometer scheme with wave front division, the difference of paths length and the ray deflection angles are linearly dependent on the ratio of the device speed to the speed of light .These additional dependences are determined by the collinearity of the reflected rays and the speed of the observer's movement, in contrast to their perpendicularity in the interferometer with the division of the wave front amplitude. As a result of the comparison of the parameters in the reference system associated with the interferometer, it is concluded from their significance that the use of frequency changes, the width of the reflected rays in the interferometer with amplitude division, and the wave front interferometer, the difference in the path lengths of the rays, frequency, angle of deflection and the width of the reflected rays is preferable.

45-52

Authors: A.P. Voronov, S.V. Naydenov, I.M. Pritula, G.M. Onyshchenko, A.F. Shchus’, I.I. Yakymenko

This research is going to explain the fast neutrons and gamma radiation registration by the new inorganic single crystals of the KDP (Potassium Dihydrogen Phosphat) group that was grown from the water solutions and activated by the thallium Tl+ or cerium Ce3+. The appearance of the luminescence upon KDP:Tl crystals irradiation with the fast neutrons is explained by secondary ionizing radiation (recoil protons and oxygen recoil nuclei) with excitation of the activator under ionization losses for inhibition. Also the recombination mechanism with the radiation defects of the hydrogen sublattice going to transmit electron excitations to the region of the Tl+ luminescence center. In the KDP:Ce crystals the excitation mechanism of the activator has a similar character, but the luminescence itself is due to the 5d  4f transition in Ce3+ ions. The detection efficiency for activated KDP:Tl and KDP:Ce crystals to the fast neutrons in comparisons with organic (plastic) scintillators were calculated theoretically and experimentally. For the crystal volume about 10x10x10 mm3 with the optimal activator concentration the fast neutron detection efficiency under irradiation of 239Pu-Be is 12% for KDP:Tl and 16% for KDP:Ce, which is in a consistent with the theoretical calculation and is not lower according to the parameters of typical organic scintillators. A high natural selectivity of the KDP scintillators to the fast neutrons due to their low sensitivity to gamma radiation was detected. Herewith the internal discrimination of n/γ signals (the ratio of detection efficiencies for the fast neutrons and gamma quants) for activated KDP crystals is 7-8 times higher than of regular plastic scintillators.

61-67

Authors: O.V. Mihal, O.V. Moroz, R.I. Starovoytov, I.V. Buriak

Modern industrial technological processes require special preparation of metal surfaces. Currently, there are different methods of surface treatment of metal. Among them, it is possible to distinguish the method of electrolytic-plasma polishing (PEP– plasma electrolytic polishing) is distinguished as an innovative, due to its ecological properties, low energy consumption per unit of surface to be processed, high speed of modification and the possibility of processing parts of complex geometric shape. The main advantage of this method of surface modification is its ecological purity, which makes it possible to apply this technology to the food and pharmaceutical industry. Despite the large number of journal publications, electrolytic plasma polishing remains an innovative surface modification method that needs to be thoroughly studied in order to improve understanding of physical processes and optimize the surface modification process. The process of obtaining electrolytic plasma polishing of copper products in a solution of ammonium sulfate with the addition of sulfuric acid is considered in the paper. The experiment was divided into two stages. At first, the samples were treated for 600 seconds each for the obtain of temperature characteristics, with a strong correlation between the load current and the electrolyte temperature was observed. Dependence of the current on the temperature of the electrolyte showed four different modes of treatment. One of the modes showed the best results. During the second series of experiments, the processing of objects from 30 to 600 seconds. As a result of the conducted studies, optimal regimes for polishing copper objects were obtained.

75-81

Authors: A.P. Shcherban, O.A. Datsenko

The method for determining the thermodynamic quantities: the partial enthalpy of dissolution α ΔH B , the activity coefficients γ αВ and activities αB a of the second component B in binary metallic systems with low solubility in the solid α-phase has been proposed. The algorithm for determining the above values is a sequence of preliminary calculations of the limiting and equilibrium distribution coefficients and construction of saturated solid solution lines for such systems with low solubility of the second component. Preliminarily obtained data are necessary for determining the partial enthalpy of dissolution and other quantities in the systems under study. Such a sequence of calculations is the proposed method for determining the thermodynamic parameters of dissolution. The values and temperature dependences of the dissolution enthalpy of component having a low solubility for such systems as Cd-Na, Cd-Tl, Te-Ga, Te-As, Te-Cu, Zn-Sn, as well as the activity coefficients γ αВ and the activities αB a of the second component in the saturating α-phase in these systems were determined. An analysis of obtained results on the enthalpy of dissolution shows that a change in the partial enthalpy with a change in the dissolution temperature is observed. When the temperature decreases from the melting point of the pure main component to the eutectic temperature, an increase in the partial enthalpies of dissolution of the second component is observed for studied systems. The Te-Ga system is characterized by a negative value HB α Δ . A negative value HB α Δ indicates an exothermic process of gallium dissolution in tellurium, in contrast to other systems in which the dissolution of the second component occurs with heat absorption. Analyzing the enthalpy of dissolution in the systems under study, it should be noted that the low values of HB α Δ < 2000 J/mol are characterized by the systems Cd-Na and Te-Ga. For systems Te-Cu, Te-As, Te-Tl, Zn-Sn HB α Δ > 15000 J/mol. Systems with a value HB α Δ > 15000 J/mol reveal a tendency to the occurrence of retrograde solubility in them. The difference in values γ αВ is found to be more than two orders of magnitude for different systems.

4-15

Authors: Yu.V. Kulish

The solutions of generalized Klein-Gordon equations are considered. The generalizations of the Klein-Gordon equation allow one to derive convergent integrals for the Green functions of these equations. The generalized equations are presented as products of the operators for the Klein-Gordon equation with different masses. The solutions of derived homogeneous equations (total fields) are sums of fields corresponding to particles with the same values of the spin, the electric charge, the parities, but with different masses. Such particles are grouped into the kinds (families, dynasties) with members which are the generations. The chronological products of the scalar fields for kinds of particles are obtained at arbitrary quantity of the generations. These chronological products are the causal Green functions of generalized Klein-Gordon equations. The Lagrangians for the generalized Klein-Gordon equations of arbitrary order are derived. These Lagrangians are used to obtain the energy-momentum tensors for the particle kinds at arbitrary quantity of generations. It is shown that the generalized Hamiltonians (for total fields) have got positive eigenvalues for all the generations. These results are derived with the use of the indefinite metrics.

23-26

Authors: M. Bondarenko, V. Knigavko, O. Zaytseva

Significant progress in understanding the mechanisms of carcinogenesis is associated with the discovery of tumor suppressor genes (or antioncogenes). It is known that in the human population, the number of normally functioning suppressor genes varies in different individuals at birth. The aim of the study was to assess the probability of cancer development in an individual with a different initial number of undamaged normally functioning antioncogenes. On the basis of the probabilistic mathematical model of carcinogenesis, the most probable age of cancer development depending on the number of intact antioncogenes was assessed. As a result of the studies, the probability of cancer development depending on the age of the patient is estimated. The dependence of the probability of cancer development in an individual on the number of undamaged antioncogenes is also investigated. The analysis of the significance of the number of tumor suppressor genes, the damage of which may be the cause of initiation of cell malignancy, has been carried out.

35-48

Authors: K.K. Merkotan, T.M. Zelentsova, N.O. Chudak, D.A. Ptashynskiy, V.V. Urbanevich, O.S. Potiienko, V.V. Voitenko, O.D. Berezovskyi, I.V. Sharph, V.D. Rusov

Problems of the Standard Model, associated with the introduction of an electromagnetic field as a linear combination of fields on which various gauge groups representations are implemented, are analyzed. In this paper, we pay attention to the fact that in any model with gauge fields, the generators which are included in the covariant derivatives can be given only up to the transition to the equivalent representation. It is proposed that dynamic models with equivalent representations of generators should be physically equivalent. It means the requirement of the Lagrangian symmetry with respect to the transition from one equivalent generators representations to another. In particular, in the Lagrangian of the Standard Model, we have raising and lowering SU (2) group generators. The group multiplication law determines only the matrix elements modules of these generators while the arguments remain uncertain. In the paper, such uncertainty is considered as a local one. At different points of space-time, generators can be expressed in various equivalent representations. The compensation of the uncertain matrix elements arguments of the SU (2) group generators can be carried out with a local U (1) - transformation with the introduction of the corresponding gauge field, which can be considered as the electromagnetic field. The advantages of such electromagnetic field introduction in comparison with the method used in the Standard Model are analyzed.

54-61

Authors: A.I. Kalinichenko, E.N. Reshetnyak, V.E. Strel’nitskij

Influence of atomic sputtering on intrinsic stress and growth rate of the coating made by method of plasma - ion deposition with use of pulsed bias potential and at different incidence angles of ions is theoretically investigated. The formula for intrinsic stress calculation in deposited coating obtained in the model of the nonlocal thermoelastic peak of the ion, taking into account atomic sputtering processes, was used to calculate the stresses in TiN and CrN coatings deposited from Ti+ and Cr+ ion beams, respectively. The stress value for the coatings considered correlates with the modulus of elasticity of the coating material. The stress curve maximum decreases and shifts to the region of higher potentials with increasing angle of incidence. This behavior is due to the sputtering of quasi-table interstitial defects that determine the level of stress in the deposited coating. A formula is proposed for the coating deposition rate, which takes into account the sputtering of the coating atoms at arbitrary bias potential and the angle of incidence of the ions. It is shown that sputtering sharply reduces the coatings deposition rate and makes it impossible to deposit TiN and CrN coatings in the DC mode at potentials on the substrate exceeding 1.7 kV and 0.7 kV, respectively, and with normal ion incidence. Sputtering has the greatest influence on the intrinsic stress and the growth rate of the coating at ion deposition at inclined angles of incidence α = 45°...70° . The results of the calculations are compared with the available experimental data.

68-71

Authors: V.K. Galaydych

The slow surface electromagnetic waves that propagate along the planar waveguide structure that contains two identical isotropic left-handed material with the vacuum (or air) gap has been considered. The possibility of propagation of slow surface electromagnetic waves of TM and TE polarizations in the frequency range at which the dielectric permittivity and magnetic permeability are negative are shown. By selecting a frequency, one, two or three modes can be excited simultaneously. The group and phase velocities of the TE polarization waves are directed in opposite directions. The frequency range of the existence of the TE mode with an antisymmetric field distribution lies above the frequency range of the existence of the TE mode with a symmetric field distribution. The TM wave, depending on the wavelength, can be either forward or backward, or have zero group velocity. The wave of TM-polarization has a slightly varying group velocity in a sufficiently wide frequency range. A rich set of different properties of these waves make them promising in applications.

78-83

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

The possible dynamics of the electron beam, formed in the vicinity of Io, the natural satellite of Jupiter, and injected toward Jupiter, has been investigated analytically. When a beam penetrates the Jupiter plasma to a certain depth, the beam-plasma instability can be developed. In this case, the distribution function of electrons is expanded additionally by excited oscillations. These electrons, when their energy is of order of a required certain value, cause UV polar light. For closing of a current, the formation of a double electric layer is necessary. The necessary parameters and conditions for the formation of a double layer with a large jump of an electric potential at a certain height have been formulated, its properties, stability, behavior over time and beam reflection in its field for closing of a current have been described. Reflection of the beam can lead to its vortex dynamics.

4

Authors: A. Burlayenko, V. Khodusov, A. Naumovets

Using a reduced isotropic crystal model the relationship between the fourth-order elastic moduli of an isotropic medium and the independent components of the fourth-order elastic moduli tensor of real crystals of various crystal systems is found. To calculate the coefficients of these relations, computer algebra systems Redberry and Mathematica for working with high order tensors in the symbolic and explicit form were used, in light of the overly complex computation. In an isotropic medium, there are four independent fourth order elastic moduli. This is due to the presence of four invariants for an eighth-rank tensor in the three-dimensional space, that has symmetries over the pairs of indices. As an example, the moduli of elasticity of an isotropic medium corresponding to certain crystals of cubic system are given (LiF, NaCl, MgO, CaF2). From the obtained results it can be seen that the reduced isotropic crystal model can be most effectively applied to high-symmetry crystal systems.

6

Authors: U. Tarabara, K. Vus, A. Kurutos, O. Ryzhova, V. Trusova, G. Gorbenko, N. Gadjev, T. Deligeorgiev

The applicability of the novel heptamethine cyanine dyes AK7-5 and AK7-6 to the detection and characterization of one-dimensional protein aggregates (amyloid fibrils) associated with numerous pathologies has been evaluated using the method of fluorescence spectroscopy. It was found that both the monomeric and aggregated forms of these dyes can bind to amyloidogenic protein lysozyme, but the concomitant changes in the electronic structure of H-aggregates render them capable of fluorescing. The growth of the hypsochromic bands with negligible changes of the monomeric peaks induced by the native protein and the opposite effects induced by the lysozyme fibrils suggest that the native lysozyme has more binding sites for the dye aggregates than fibrillar protein, while the fibril grooves represent specific binding site for the dyes monomers. The observed spectral behavior of the cyanine dyes, viz. significant distinctions in the fluorescence responses produced by the monomeric and fibrillar forms of lysozyme, suggest the possibility of recruiting these compounds as fluorescent amyloid markers along with the classical amyloid marker Thioflavin T.

8

Authors: O. N. Shekhovtsova

In this note I review the current status of electron-positron annihilation into the π⁺π⁻η final state from both experimental and theoretical sides. The theoretical studies of the reaction are discussed in framework of three theoretical approaches: the Vector Meson Dominance Model, the Resonance Chiral Theory with vector and axial-vector resonances and within the extended nonlocal version of the Nambu-Jona-Lasinio model. In the case of the Vector Meson Dominance model the three vector ρ-mesons are included, i.e. the main ρ(770) state and the excited ρ(1400) and ρ(1700) states. For the theoretical approach based on the Resonance Chiral Theory lagrangian the theoretical prediction includes either the lightest ρ(770) state only or the superposition of the main state ρ(770) with the ρ(1400), ρ(1700) states. Finally, the theoretical calculations in the framework of the Nambu-Jona-Lasinio model include both the lightest ρ(770) state and its first excited state ρ(1400) . To sum up the theoretical predictions of these three approaches are compared with the recent experimental data from Novosibirsk groups (SND and CMD experiments) and from the BaBar Collaboration. In addition, main points of studies on application of the Conservation Vector Current hypothesis to estimate the cross channel decay width, τ→π⁻π⁰ητ , are discussed. The last subject is an investigation of the OZI and G-parity violated decay ϕ→π⁺π⁻η.

9

Authors: R. V. Skorokhod, O. M. Buhay, V. M. Bilyk, V. L. Denysenko, O. V. Koropov

A computer code to calculate the time and space dependencies of the defect and component concentrations of a binary alloy is developed. This code is based on the theoretical model for radiation-induced segregation governed by first and second Fick’s laws with taking into account inverse Kirkendall effect. The system of three coupled partial differential equations for concentrations of one of components and point defects is converted to the system of ordinary differential equations in time by a discretization procedure. Numerical solutions of this system are obtained under appropriate initial and boundary conditions by means of the MATLAB. The modeling of radiation-induced segregation in binary Fe-Cr alloys is carried out for various initial concentrations of components, temperatures, dose rates and doses. The process of achievement of steady state at dose rising is demonstrated. The calculated concentration profiles are compared with experimental profiles published in literature. The sensitivity of model to input parameters is done and the capabilities of proposed model are estimated. This computer code for multicomponent alloys is developed.

24

Authors: G. I. Gakh, M. I. Konchatnij, N. P. Merenkov, A. G. Gakh

The emission of the hard photon from the initial state is considered. The nucleon polarization and the differential cross sections for some experimental conditions have been calculated. The case of the emission of the collinear (with respect to the direction of the electron beam momentum) photon is considered separately. The differential cross section, the nucleon polarization, the correlation coefficients for both polarized nucleons (provided the electron beam is unpolarized or longitudinally polarized), the transfer polarization from the longitudinally polarized electron beam to the nucleon have been calculated. The photon energy distribution for the reaction e⁺e⁻ → h₁h₂γ where h₁ and h₂ are some hadrons for the case of the collinear photon, emitted in the initial state, has been calculated. As h₁h₂ final state we considered some channels, namely: two spinless mesons (for example,π⁺π⁻K⁺K⁻), two spin–one particles (for example, ρ⁺ρ⁻d⁺d⁻), and the channels πa₁ (1260) and Δ(1232)Ñ . The photon energy distributions are calculated in terms of the form factors of the γ* → h₁h₂ transition (γ* is the virtual photon).