Vol 60, No 3 (2017)

The elastomagnetic parameters of a magnetic fluid kept by magnetic levitation in a tube placed horizontally in a strong magnetic field are measured, including the oscillation frequency, the ponderomotive and dynamic elasticity coefficients, the magnetization curve, and the magnetic field strength and its gradient. Results of calculations for the model of ponderomotive elasticity for the examined sample of the magnetic fluid corrected for the resistance of the moving viscous fluid are in good agreement with the experimental magnetization curve. The described method is of interest for a study of magnetophoresis, nanoparticle aggregations, viscosity, and their time dependences in magnetic colloids.

The possibility of adapting the Maxwell–Parker–Moffat differential equations to electromagnetic fields observed on the Earth is considered. The limits of applicability of these equations as a function of selected values of the similarity criterion are investigated, and an explanation for some effects observed in the electromagnetic field of the Earth is given.

A method for generating exact solutions of the equations of the scalar field dynamics in the case of flat Friedmann–Robertson–Walker space on the basis of form-invariant transformations is considered. A method for estimating the divergence of the exact and approximate solutions from the number of e-folds and the parameters of the cosmological perturbations is proposed.

Results of analysis of the orbital evolution of Etalon-1 and Etalon-2 artificial satellites during a 500-year period are presented. It is demonstrated that the stable Lidov–Kozai resonance acts on the satellites during the entire time period, thereby leading to an increase in the orbit eccentricities. During a 300-year period the eccentricities reach values greater than 0.5 and then oscillate with large amplitude, not dropping below 0.3. The inclinations and semimajor axes also undergo long-term oscillations. After a 200-year increase in the eccentricities, the two more piecewise-stable apsidal and nodal resonances start to act. By the end of the 500-year period, insignificant increase in the MEGNO parameter is observed.

Magnetohydrodynamic waves, having unusual dispersion and resonance properties, have been found within the framework of the linear kinetic theory. This modification is due to the energetic ion component of the cosmic plasma. Calculations (estimates) illustrate the possibility of this modification by H⁺, He⁺, and O⁺ ions, for example, in the magnetosphere of the Earth.

The paper generalizes results of investigating the localization and fragmentation of plastic deformation in aluminum single crystals having a different orientation of the compression axis and lateral faces. The surface topography of the samples induced by plastic deformation includes such elements as deformation bands, folds and shear markings observed at different scale levels (macro, meso and micro). The morphological uniformity is identified for these elements in the aluminum single crystals. Depending on the resolution required, the quantification of the shear deformation markings is provided by the optical microscope and the scanning and transmission electron microscopes using the replication technique. The following parameters are obtained: the distance between the nearest shear deformation markings, width of shear markings, local shear; shear γ; the single-crystal volume fraction in which the shear deformation occurs at macro, meso, and micro-levels. The statistical examination of the shear deformation markings in aluminum single crystals with different geometry is performed at these three levels and allows us to conclude that the micro-scale level makes the main contribution to the shear deformation.

The mechanisms of forming nanostructured, nanophase layers are revealed and analyzed in austenitic steel subjected to surface alloying using an electron-plasma process. Nanostructured, nanophase layers up to 30 μm in thickness were formed by melting of the film/substrate system with an electron beam generated by a SOLO facility (Institute of High Current Electronics, SB RAS), Tomsk), which ensured crystallization and subsequent quenching at the cooling rates within the range 10⁵–10⁸ K/s. The surface was modified with structural stainless steel specimens (SUS 321 steel). The film/substrate system (film thickness 0.5 μm) was formed by a plasma-assisted vacuum-arc process by evaporating a cathode made from a sintered pseudoalloy of the following composition: Zr – 6 at.% Ti – 6 at.% Cu. The film deposition was performed in a QUINTA facility equipped with a PINK hot-cathode plasma source and DI-100 arc evaporators with accelerated cooling of the process cathode, which allowed reducing the size and fraction of the droplet phase in the deposited film. It is found that melting of the film/substrate system (Zr–Ti–Cu)/(SUS 321 steel) using a high-intensity pulsed electron beam followed by the high-rate crystallization is accompanied by the formation of α-iron cellular crystallization structure and precipitation of Cr₂Zr, Cr₃С₂ and TiC particles on the cell boundaries, which as a whole allowed increasing microhardness by a factor of 1.3, Young’s modulus – by a factor of 1.2, wear resistance – by a factor of 2.7, while achieving a three-fold reduction in the friction coefficient.

Sintering of a ZrO₂–СaO nanocrystalline system under the action of a constant magnetic field within the temperature interval 1200–1400°C gives rise to predetermined changes in microstructure and morphology of the particles. A method is proposed for hardening ZrO₂(CaO) ceramics and a quantitative estimation of its contribution into the changes of its mechanical properties and fine crystalline structure parameters. A possibility is demonstrated for using constant magnetic field for deliberate changes of microstructure and mechanical properties of porous ceramics.

Potential use of hard synchrotron radiation (SR) with the quantum energy above 25 keV is discussed aiming to solve a number of research tasks on investigation of structural changes taking place in materials. The advantages and limitations of the use of hard SR for diffraction studies are evaluated. A review of the principal techniques is made wherein application of hard SR both promotes certain experimental investigations and frequently allows obtaining new structural data unavailable with X-ray tubes.

A fundamental problem in hadron physics is to obtain a relativistic color-confining, first approximation to QCD which can predict both hadron spectroscopy and the frame-independent light-front (LF) wavefunctions underlying hadron dynamics. The QCD Lagrangian with zero quark mass has no explicit mass scale; the classical theory is conformally invariant. Thus, a fundamental problem is to understand how the mass gap and ratios of masses – such as m_ρ/m_p – can arise in chiral QCD. De Alfaro, Fubini, and Furlan have made an important observation that a mass scale can appear in the equations of motion without affecting the conformal invariance of the action if one adds a term to the Hamiltonian proportional to the dilatation operator or the special conformal operator and rescales the time variable. If one applies the same procedure to the light-front Hamiltonian, it leads uniquely to a confinement potential κ⁴ζ² for mesons, where ζ² is the LF radial variable conjugate to the \( q\overline{q} \) invariant mass squared. The same result, including spin terms, is obtained using light-front holography – the duality between light-front dynamics and AdS₅, the space of isometries of the conformal group if one modifies the action of AdS₅ by the dilaton\( {e}^{\kappa^2}{z}^2 \) in the fifth dimension z . When one generalizes this procedure using superconformal algebra, the resulting light-front eigensolutions predict unified Regge spectroscopy of meson, baryon, and tetraquarks, including remarkable supersymmetric relations between the masses of mesons and baryons of the same parity. One also predicts observables such as hadron structure functions, transverse momentum distributions, and the distribution amplitudes defined from the hadronic light-front wavefunctions. The mass scale κ underlying confinement and hadron masses can be connected to the parameter \( {\Lambda}_{\overline{MS}} \) in the QCD running coupling by matching the nonperturbative dynamics to the perturbative QCD regime. The result is an effective coupling α_s(Q²) defined at all momenta. The matching of the high and low momentum transfer regimes also determines a scale Q₀ which sets the interface between perturbative and nonperturbative hadron dynamics.

A system of equations describing resonant interaction of bending waves of a thin plate with a liquid or gas flow around it leading to the evolution of wind instability is derived in a quasilinear approximation. It is demonstrated that as a result of the reverse effect of waves on the flow, a quasilinear relaxation of liquid particle distribution function occurs to the state with a plateau that leads to a slow smoothing of the velocity profile in the liquid in the resonant region and thereby to elimination of the reason causing the growth of waves in the linear stage of instability evolution. The resultant energy transferred from the flow to the waves in the course of quasilinear relaxation is calculated. The wavelength of the instability that most quickly grows due to evolution of the wind instability is obtained.

Polymer particles with sizes 0.3–0.4 μm are synthesized based on chitosan and chondroitin sulfate with incorporated CdTe (core) and CdSe/ZnS (core–shell) quantum dots. Their morphological and spectral properties are investigated by the methods of dynamic scattering, electron microscopy, and absorption and luminescence spectroscopy at temperatures from 10 to 80°С. Spectral effects associated with a change in temperature (a red shift and a decrease in the amplitude of the photoluminescence spectrum) can be explained by the temperature expansion of the quantum dots and activation of surface traps. It is shown that the temperature sensitivity of spectra of the quantum dots incorporated into the biopolymer particles is not less than in water. To develop an optical temperature sensor, the core quantum dots are more preferable than the core–shell quantum dots.

The paper considers the strain rate sensitivity of flow stress in Ni₃Ge single crystals having high-energy antiphase boundaries detected in experiments for the strain rate variation. The concentration of point defects is estimated by the model of plastic deformation of alloys having L1₂ structure. These point defects generated by plastic deformation, annihilate both mutually and on dislocations. It is shown that at higher temperatures of deformation, the anomalous strain rate sensitivity of the flow stress observed during the strain rate variation, can be caused by the migration of and interaction between the point defects and dislocations.

The exact problem of electromagnetic wave propagation in a multilayer nanostructure with complex values of dielectric permittivity is solved. The contribution to the refractive index of an additive to the dielectric constant connected with the injected carriers is taken into account. Within the framework of this problem, it is shown that an anomalous temperature dependence of the threshold current of injection lasers based on nanoheterostructures is related to the anti-waveguide action of injected carriers. A quantum-well heterostructure based on InGaAs/AlGaAs/GaAs nanosystems used for fabrication of 0.94-1.14 μm lasers is considered. The applied techniques and approaches are also acceptable for the optimization of multilayer nanostructures based on other solid solutions. As an optical model of the active region of injection lasers based on nanostructures, a planar multilayer dielectric waveguide with complex values of dielectric permittivity in the layers is considered. It is shown that with decreasing thickness of the active region of injection lasers, the dependence of the mode gain on the local gain is essentially sublinear. The reason for this is the antiwaveguide action of electrons. The results of calculations of the temperature dependence of the threshold current of injection lasers indicate the presence of a critical point Tc, at which a sharp decrease in the characteristic temperature occurs. The performed calculations and optimization of the temperature dependence of emission characteristics of injection lasers based on nanostructures show that the anomalous behavior of the temperature dependence of the threshold current is also associated with the weakening of the waveguide properties of theirs active region.