Vol 80, No 11 (2016)

One-dimensional nanocomposites Zn_1–xCo_xO_1–yС_у:nCo₃O₄ and solid solutions Zn_1–xCo_xO_1–yС_у, which are promising photocatalysts for the oxidation of toxic organic compounds in visible light, are obtained via the thermolysis of Zn_1–xCo_x(HCOO)(OCH₂CH₂O)_1/2 (0.1 ≤ x ≤ 0.5) precursor in a controlled gaseous atmosphere.

Gd_xMn_1–xSe (0 ≤ х ≤ 0.15) solid solutions are synthesized on the basis of manganese monoselenide. Their magnetic and electrical properties are studied in the temperature range of 80–900 K in magnetic fields up to 10 kOe. An FCC lattice with the Fm3m space group and antiferromagnetic ordering of the magnetic moments of manganese ions is found. A monotonic reduction in the Néel temperature and an increase in the effective magnetic moment along with the gadolinium concentration are observed. Anomalies in the temperature dependence of electrical resistivity and a shift in the temperatures of anomalies in a magnetic field are found.

Features of the optical and magneto-optical properties of polycrystalline Со–Р films with nanometer thickness are established experimentally. It is found that the spectra of optical parameters n and k and magnetic circular dichroism depend largely on film thickness, suggesting that magneto-optical activity is governed by different mechanisms in thin films and bulk materials.

Contact melting with and without electrotransfer is studied in Sn–Bi systems with small additions of indium to each component. The effect admixtures have on the rate of contact melting is shown to be unclear. The structures of the obtained alloys are highly inhomogenous with multiple inclusions of dendrites. An X-ray analysis of the transformed interlayers is performed. A number of intermetallides are observed, including ones not found on the phase diagrams of binary systems. An attempt is made to explain these findings.

A procedure for and the results from studies on directly estimating the size and number of submicron particles at the moment of the destruction and disintegration of solid bodies are described. Experiments require the breaking up of metallic rods or the crushing of rock samples subjected to uniaxial compression, and continuous monitoring of the size of particles by laser spectrometry. The formation of submicron particles with minimum sizes of ∼0.1 μm is observed. The size distribution and number of these particles depend on the structural and physical parameters of the solid bodies.

An exact solution for a model describing the equilibrium behavior of an ensemble of Ising chains with nonmagnetic intersite repulsion of nearest neighbors and an equilibrium distribution of nonmagnetic impurities is obtained using the transfer matrix technique. The possibility of exciting quantum phase transitions using the intersite repulsion parameter in a system is demonstrated. Proximity to the critical points of these transitions has a substantial effect on the temperature dependence of a system’s magnetic susceptibility.

Vibrational spectra of graphene, its multilayer and hydrogenated modifications have been considered. Interpretation of experimental Raman spectra based on analytical models and simulation by Hyper-Chem program have been done for graphene like structures for samples obtained by methane-hydrogen mixture deposition on sapphire substrate.

The results from developing and testing a software package for calculating the amplitudes and phases of electron scattering in polyatomic systems are presented. The potential with which an excited electron moves in a medium is constructed using the muffin-tin approximation with Hartree–Fock exchange interaction. Tests of the package for metals, oxides, and iron-bearing water sulphate solutions show that structural parameters can be derived with high degrees of accuracy (the error for interatomic distances is ~0.01 Å; for coordination numbers, it is ~7%). Using the developed approach and software, analysis of the Ag K-EXAFS spectra of silver nanoparticles in silica glass allow us to determine the average structural parameters of Ag–O and Ag–Ag bonds.

A way of calculating partial coordination numbers is proposed for bimetallic nanoparticles with different radial distributions of atoms relative to a selected center. It is based on a continuum approximation for the atomic density distribution in the volume of nanoparticles (continuum model) and does not require the use of cluster-based models of nanoparticles to obtain information on the distribution of components in nanoparticles. The results obtained in this manner are compared to those from directly calculating the partial coordination numbers in atomic clusters.

Solid solutions of (1–х)NaNbO₃–xSr₂(Ca₂)Nb₂O₇ (0 ≤ x ≤ 0.2, Δx = 0.025) binary systems are fabricated via solid-phase reactions with subsequent sintering using standard ceramic technology. Patterns in the formation of their crystalline structure and dielectric properties are established in a wide interval of temperatures and frequencies.

Experimental data on the density and surface tension of lead–lithium melts, obtained using the large drop method, are presented as functions of temperature. These data are used in a computational experiment to construct both two- and three-dimensional drop profiles. It is shown that this approach allows us to estimate the effect errors in physical parameters have in determining a system’s configuration.

Bulk nanostructured Co–P/Cu and Al₂O₃/Co–P composites are fabricated via dynamic compaction. The initial core–shell particles are synthesized by means of chemical deposition. Structural and magnetic characteristics of the composites are investigated. It is shown that the use of composite particles allows homogeneous compacts with the structure and magnetic characteristics of initial powders to be obtained.

The temperature dependence of the resistivity of a composite rich in multi-walled carbon nanotubes (95 wt % nanotubes and 5 wt % polymer) is studied at 77–450 K. It is shown that the high nanotube content allows us to identify defects that emerge as maxima on the temperature dependence of resistivity.

Results from systematic experimental studies of the temperature dependences of the surface wetting of a number of EK-173, 12Cr18Ni9Тi, and 12Cr18Ni10Тi structural steels using liquid lead, bismuth, and a eutectic melt of PbBi with lithium under vacuum and/or an argon protective atmosphere. Critical wetting temperatures are found on the polytherms of the wetting of EK-173, 12Cr18Ni9Тi, and 12Cr18Ni10Тi steels using lead, bismuth, and a eutectic melt of PbBi under vacuum. It is shown that steel of EK-173 grade is more stable than 12Cr18Ni9Тi structural steel when in contact with a eutectic melt of PbBi at higher temperatures. Steel wetting is considerably higher under vacuum than in a protective argon atmosphere. Study of the wetting of 12Cr18Ni10Тi steel using liquid alloys of (PbBi)_eut with lithium revealed a tendency toward improved wetting of steel with higher lithium content in a eutectic melt of PbBi.

Patterns of the generation of nanocluster icosahedral substructures of pure iron metallic glass upon quenching a melt with two competing processes, athermal nucleation and the growth of polytetrahedral local formations and their decomposition under the impact of thermal fluctuations, are investigated by means of molecular dynamic simulation.

Fractal analysis is used to study patterns of photo-induced light scattering in stoichiometric LiNbO₃ single crystals and in a series of LiNbO₃:Zn (0.018–0.88 wt %) single crystals. It is found that the concentration of laser-induced defects depends on that of Zn, and that energy is redistributed between the layers of laser-induced scattering.

The interrelation between the polarizability of structural defects (elastic dipoles) in noncrystalline materials and their fourth-order elastic modulus that determines the change in the value of the shear modulus of amorphous material during structural relaxation is established. The obtained results agree with computer simulations of amorphous copper and with shear-modulus relaxation experiments for Pd₄₀Cu₃₀Ni₁₀P₂₀ glass.