Том 59, № 8 (2016)

The form of the Gribov horizon functional in a linear gauge in the Gribov–Zwanziger theory is discussed.

A gravitational interaction of a scalar field with conformal coupling \( n\frac{R}{6}{\upvarphi}^2 \) (n = const) is considered within the framework of the affine-metric theory of gravitation, with the interaction with torsion and nonmetricity taken into account. It is shown that for different values of the constant n different forms of nonlinearities are induced in the scalar field and, in particular, for n = –1 a nonlinearity corresponding to the potential of the axion field is induced. Possible astrophysical consequences of such an effect are considered.

Within the framework of the modified potential cluster model with forbidden states and classification of states according to the Young tableaux, the possibility is considered of describing experimental data for the astrophysical S-factor of radiative p¹⁶O capture to the ground state of the ¹⁷F nucleus. It is shown that on the basis of E1 transitions from p¹⁶O scattering states to the ground state of ¹⁷F in the p¹⁶O channel overall success is achieved in explaining the magnitude of the measured cross sections at astrophysical energies.

A cosmological model is considered, in which two ideal fluids interact: dark energy and dark matter, in a homogeneous and isotropic flat Friedmann–Lemaître–Robertson–Walker Universe with scattering. Scattering in this Universe is investigated in two ways: in terms of bulk viscosity and with the help of the entropic model. The interaction between dark energy and dark matter is described in terms of parameters of the equation of state for dark energy, which take account of dissipative properties of the Universe. In the example of the model of the Universe with a singularity known as the Little Rip, application of a formalism describing dissipative properties is demonstrated. An analytical representation of this model in terms of thermodynamic parameters of the equation of state for dark energy, taking dissipation into account, is obtained. In the expression for the coefficient of bulk viscosity, corrections are taken into account which are due to the interaction between dark energy and dark matter.

Vector formulations of laws of reflection and refraction of plane electromagnetic waves from the plane metasurface that separates two isotropic media and is characterized by phase gradients are obtained and analyzed. The media support the forward or backward normal waves that differ by identifiers. Critical angles of total internal reflection are presented, and conditions of occurrence of negative refraction and negative reflection are specified. Retroreflection and special cases of wave refraction are considered, and restrictions on the metasurface parameters are given.

The effect of hydrogen sulfide in the concentration range of 0–100 ppm on the characteristics of thin films of tin dioxide and tungsten trioxide obtained by the methods of magnetron deposition and modified with gold in the bulk and on the surface is studied. The impurities of antimony and nickel have been additionally introduced into the SnO₂ bulk. An optimal operating temperature of sensors 350°C was determined, at which there is a satisfactory correlation between the values of the response to H₂S and the response time. Degradation of the sensor characteristics is investigated in the long-term (~0.5–1.5 years) tests at operating temperature and periodic exposure to hydrogen sulfide, as well as after conservation of samples in the laboratory air. It is shown that for the fabrication of H₂S sensors, the most promising are thin nanocrystalline Au/WO₃:Au films characterized by a linear concentration dependence of the response and high stability of parameters during exploitation.

The behavior of p₁–n₁–p₂–n₂-structure with contacts to n₁- and n₂-regions was studied. It is shown that at such double electrode closing, four-layer structures do not have stationary state in a certain voltage range, i.e. they develop instability accompanied by the generation of relaxation current pulses. A physical model is proposed for the observed instability.

The paper presents the results of research focusing on the processes occurring when powerful laser radiation interacts with refractory oxide targets. To visualize formation of the nanoparticle cloud and large fragments, the authors used laser illumination and laser monitor methods. Image analysis allowed studying the dynamic of cloud formation from nanoparticles and determining the nature of its interaction with surrounding air. It was established that it is possible to mostly avoid the formation and ejection of a multitude of drops from the crater, if the target is evaporated by fiber laser radiation pulses with duration of no more than 200 μs. With pulse duration of 120 μs, peak power of 600 W and radiation power density of 0.4 MW/cm², mass nanoparticle output was 30 mass%, which is 1.4 more than when the target is affected by continuous radiation of the same power.

Using single crystals of the Ni₄₉Fe₁₈Ga₂₇Co₆ (at.%) alloy, oriented along [001]- and [123]-directions, cyclic stability of superelasticity is investigated in isothermal loading/unloading cycles at T = A_f +(12–15) K (100 cycles) under compressive stress as a function of given strain per cycle, presence of disperse γ-phase particles measuring 5–10 μm, austenitic (B2 or L2₁) and stress-induced martensitic crystal structure (14M or L10). It is shown that single-phase L2₁-crystals demonstrate high cyclic stability during L21–14M-transitions with narrow hysteresises Δσ < 50 MPa in the absence of detwinning of the martensite. During the development of L2₁–14M stress-induced transformation, the reversible energy ΔGrev for these crystals exceeds the dissipated energy ΔG_irr, and ΔG_rev/ΔG_irr = 1.7–1.8. A significant degradation of superelasticity is observed in [123]-oriented crystals during the development of L2₁–14M–L1₀-transformations followed by detwinning of the L10-martensite crystals and heterophase (B2+γ) single crystals, irrespective of their orientation during the B2–L10-transition. In the latter case, martensitic transformations are characterized by a wide stress hysteresis Δσ ≥ 80 MPa and the dissipated energy exceeds the reversible energy ΔG_rev/ΔG_irr = 0.5. The empirical criterion, relying on the analysis of the reversible-to-irreversible energy ratio, ΔG_rev/ΔG_irr, during stressinduced martensitic transformations, can be used to predict the cyclic stability of superelasticity in NiFeGaCo alloys subjected to different types of heat treatment.

A solution of linearized systems of equations of the dynamic elasticity theory and of the heat conductivity equation is derived. It is shown that in this case, the velocity of longitudinal sound waves c_sl is a function of the temperature T and depends strongly on T . The attenuation coefficient γ (k) of these waves is calculated and the dependence obtained is graphically illustrated.

Effect of ultrasonic treatment on the molecular parameters of polymeric additives based on polyalkyl acrylate is investigated. The viscosity, temperature, and energy characteristics of high-wax crude oil and solutions of petroleum wax in decane and aviation fuel TS-1 in the presence of initial and ultrasonified additives are determined. Results obtained indicate that the pour point depression ability of the additives is not reduced after treatment in an ultrasonic field.

Temperature distribution along the discharge of a He–Ne laser is studied, its non-uniformity is detected, and possibility of its regulation is analyzed.

A problem is discussed of the microwave generator power switching with the use of high-speed subnanosecond avalanche diodes. A scheme of the measurement setup, a photo of the switch design, and the results of experimental studies are presented.

The problem of thermal interaction between the gold nanoparticle heated by pulse-periodic laser radiation and the biotissue in which the nanoparticle is placed is numerically solved. A linear dependence between the heating time of the medium and the ratio of the time between laser radiation pulses to the time of the pulse for particles equally spaced in the biotissue is obtained. From the results of numerical calculations of biotissue heating by the single particle heated by periodic laser radiation the distance between the particles necessary for effective thermal damage of the biotissue is estimated.

The feasibility of producing protective radio-absorbing shielding materials on the basis of differently shaped surfaces with nanostructured coatings is investigated. Combinations of special nanostructured materials and technical solutions for the shape of the absorbing surface were tested, in order to create efficient nanocoatings. It is shown that the coatings of interest that meet the requirements of low reflection and high attenuation of transmitted radiation combined with low coating thickness can be developed, using corrugated surfaces. Corrugated chicken egg-packing cell samples with nanostructured carbon coatings were examined and found to allow for effective shielding of electromagnetic radiation and to exhibit minimum reflection coefficients as compared to construction materials.

The topical problem of effective verification of digital circuits of different physical systems remains a hot topic. Devices ranging from embedded components to perform specific tasks or experiments to modern communication clusters used for data transmission are concerned. The method of synthesis of the test sequences is based on injection of faults into a reference circuit and deriving a corresponding distinguishing sequence which detects this fault. The method is known as mutation testing and is widely used for the synthesis of high-quality verification tests for digital circuits. Naturally, test suits that detect faults of various classes, and larger amount of faults, are of greater interest. The paper studies the correlation between different test suits derived for different mutant types. The considered fault types include 1) single stuck-at faults, 2) bridges, and 3) hardly detectable faults, i.e., slightly modifying the behavior of a single circuit gate. Tests for detecting faults of each type are derived for the B01-B10 benchmark package (ITC’99 benchmarks (Second Release)), which are components of physical systems intended for various applications including processing of data obtained, load balancing systems, etc. Experiments aim to access the fault coverage of the test derived for one mutant type against faults of other types. It is shown experimentally that the synthesis of tests of one type, including a single stuck-at fault test, is insufficient, because its fault coverage for faults of other types cannot exceed 60%.