Magnetooptical phenomena in disperse systems in uniform linearly oriented magnetic fields

The theory of magnetooptical phenomena in disperse systems subjected to constant magnetic fields is outlined. A magnetooptical method is proposed for determining the magnetic characteristics and size distribution of particles in polydisperse colloidal solutions and suspensions. The magnetooptical properties of aqueous colloids of anisaldazine and acetoxybenzalazine are studied and the size distribution functions of dispersed particles are determined.     

Effect of the Ni/Cu ratio on the composition and catalytic properties of nickel-copper alloy in anisole hydrodeoxygenation

The activity of NiCu-SiO₂ catalysts with a metal content of 90% and different Ni/Cu ratios has been investigated in the hydrodeoxygenation of anisole, a model compound of bio-oil, at 280°C and 6 MPa. A homogeneous phase composition of the active component has been synthesized by the co-decomposition of nickel and copper nitrates followed by the introduction of SiO₂ as a stabilizer. The resulting catalysts have been characterized by temperature-programmed reduction, X-ray powder diffraction, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy combined with energy-dispersive microanalysis. The bulk and surface composition of active-component particles has been determined by XPS and X-ray diffraction. In all of the catalysts containing 15–85 wt % Ni, there are two types of solid solutions. One has a constant composition, Cu_0.95Ni_0.05, which is independent of the Ni/Cu ratio in the catalyst; in the other, the nickel stoichiometry increases with an increasing Ni content of the active component. A correlation has been established between the Ni/Cu ratio and the rate constants of the reaction examined and between the Ni/Cu ratio and the degree of hydrodeoxygenation for all samples. The most active catalyst is Ni85Cu5-SiO₂.     

Liquid-Phase Heterogeneous Oxidation of Hydroxypivalaldehyde with Oxygen in Alkaline Aqueous Solution in the Presence of Supported Palladium Catalyst

The kinetics of a model reaction of hydroxypivalaldehyde oxidation with molecular oxygen in alkaline aqueous solution in the presence of 4% Pd/Al2O3 was studied with the aim of searching for promising heterogeneous catalysts for D-glucose oxidation.     

Heavy baryons in the nonperturbative string approach

Physics of Atomic Nuclei - We present some piloting calculations of the short-range correlation coefficients for light and heavy baryons and of the masses of the doubly heavy baryons...     

Higgs bosons in the simplest SUSY models

Nowadays, in the MSSM, the moderate values of tan β are almost excluded by the LEP II lower bound on the mass of the lightest Higgs boson. In the next-to-minimal supersymmetric standard model (NMSSM), the theoretical upper bound on it increases and reaches a maximal value in the limit of strong Yukawa coupling, where all solutions to renormalization-group equations are concentrated near the quasifixed point. For a calculation of the Higgs boson spectrum, the perturbation-theory method can be applied. We investigate the particle spectrum within the modified NMSSM, which leads to the self-consistent solution in the limit of strong Yukawa coupling. This model allows one to get m _h～125 GeV at tan β≥1.9. In the model under investigation, the mass of the lightest Higgs boson does not exceed 130.5±3.5 GeV. The upper bound on the mass of the lightest CP-even Higgs boson in more complicated supersymmetric models is also discussed.     

The effective screening parameters in the theory of internal conversion in the M shell of the atom

An investigation is conducted into the dependence of the effective screening parameters ( = Z-Z_eff) on Z, multipolarity, parity, and nuclear transition energy in the theory of internal conversion in the M shell of the atom, taking account of Thomas-Fermi-Dirac and Gashpar screening with semiempirical corrections.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 9, pp. 103–109, September, 1971.We are grateful to O. Dragoun for having allowed us to use Pauli's ICC table.     

Physical meaning of nonholonomic strain measure

The paper overviews the main approaches to the introduction of strain measures. It has been concluded that the physical meaning of certain measures is insufficiently clear. Problems concerning the definition of the physical meaning of the nonholonomic asymmetric strain measure introduced in the framework of a multiscale model, which is based on the physical theory of plasticity, are discussed. This measure is calculated using the corotational integration of the asymmetric and frame-independent strain rate measure equal to the relative velocity gradient. The integration is carried in terms of the corotational coordinate system whose instantaneous motion is determined by averaging the spins of mesoscale elements. It is shown that if elastic distortions are neglected, the introduced mesoscale strain measure is equal to the sum (over all slip systems of the crystallite) of products of accumulated shear multiplied by the basis dyads of the slip systems. The averaging reveals that additional contribution to the value of the macroscale strain measure is attributed, along with elastic distortions, to corotational terms that appear due to different rotation rates of the introduced macroscale corotational frame and crystallite lattices. In view of the absence of analytical expressions for the meso- and macroscale spins, the physical meaning of the macroscale nonholonomic measure is defined in numerical experiments for several strain paths. Calculations have shown that contributions of the elastic and corotational components to the macroscale nonholonomic strain measure are negligible for strain paths of different complexity.     

Glass crystallization synthesis of ultrafine hexagonal M-type ferrites: Particle morphology and magnetic characteristics

This review concerns the synthesis and functional properties of ultrafine particles of M-type hexagonal ferrites prepared by the most advanced process of oxide glass crystallization. Hexaferrite phase formation during the heat treatment of multicomponent oxide glasses of various chemical compositions containing boron and/or silicon oxides as glass formers is considered. This route is useful to prepare assemblies of single-crystal strontium barium hexaferrite particles in the range of average particle sizes from tens of nanometers to several micrometers. The resulting glass ceramics and magnetic particle assemblies recovered from them are characterized by high coercive forces, approaching the theoretical limit for such compounds, and high magnetizations, close to the magnetization value for coarse-grained materials.