Acceleration of Cosmic Rays to Energies above 1015 eV by Transrelativistic Shocks

Journal of Experimental and Theoretical Physics - MHD flows with transrelativistic 4-velocities Γβ ~ 1, which are realized in Ib/c-type supernovae and after the coalescence of neutron...     

Haldane limits via Lagrangian embeddings

In the present paper we revisit the so-called Haldane limit, i.e. a particular continuum limit, which leads from a spin chain to a sigma model. We use the coherent state formulation of the path integral to reduce the problem to a semiclassical one, which leads us to the observation that the Haldane limit is closely related to a Lagrangian embedding into the classical phase space of the spin chain. Using this property, we find a spin chain whose limit produces a relativistic sigma model with target space the manifold of complete flags U(3)/U³(1). We discuss possible other future applications of Lagrangian/isotropic embeddings in this context.     

Fractal dimension of cluster boundaries in porous polycrystalline HTSC materials

The fractal dimension of the boundaries of clusters formed by pores and granules in polycrystalline materials is shown to be determined by the sample density and crystallite sizes. The dependence of the fractal dimension on the density has a maximum. It is shown that the maximum diamagnetic response can be obtained in a porous high-temperature superconductor with a porosity of 50?C60% and small crystallite sizes.     

Kinetics of α-olefin metathesis over the heterogeneous catalytic system (MoOCl<Subscript>4</Subscript>/SiO<Subscript>2</Subscript>)-SnMe<Subscript>4</Subscript>

The kinetics of 1-hexene and 1-octene metathesis over the (MoOC_l4/SiO₂)-SnMe₄ catalytic system at 27 and 50°C has been investigated. The rate constants of the forward and reverse reactions and the catalyst deactivation constants have been measured. The number of active sites has been determined to be 10–13 mol % of the total number of molybdenum atoms.     

A new method of synthesis of the B<Subscript>3</Subscript>H<Stack><Subscript>8</Subscript><Superscript>−</Superscript></Stack> anion

A new method of synthesis of the B₃H₈⁻ anion has been suggested. The method uses the reaction of some metal halides (CuCl, SnCl₂, CrCl₃, PbF₂, PbCl₂, PbBr₂, and BiCl₃) with sodium tetrahydroborate. It is characterized by high (up to quantitative) yields and simplicity of isolation of the target products ((n-C₄H₉)₄N)[B₃H₈] and Cs[B₃H₈].     

Plane nonaxisymmetric deformation of a viscoelastic cylinder with consideration of its physical and geometric nonlinearity

The nonaxisymmetric plane problem of the nonlinear theory of viscoelasticity is solved for a cylinder reinforced by an elastic circular shell. The cylinder has an internal cut resembling a Maltese cross in shape. The identification of the nonlinear endochronous theory of aging viscoelastic materials is conducted by a genetic algorithm method on the basis a nonmonotonic experimental stress-strain dependence. Some numerical results obtained for the stress-strain state of this cylinder under the action of internal pressure are discussed with consideration of the above physical nonlinearity and the finite logarithmic strains.     

Thermocycle and Evolutionary Combinatorics in the Genesis and Evolution of Protobiopolymers. Basic Kinetic Principles

The basic kinetic principles of genesis and evolution of protobiopolymeric molecules are discussed. An approach combining polymerization and selection of macromolecular structures is the thermocycle providing the thermodynamic feasibility of formation of the monomer–monomer bond and kinetic selection of structures by picking more regular complexes. The basic kinetic principle of the successful evolutionary process is formulated as follows: the systems win if the mechanism of their development involves exponential growth steps.     

Magnetocaloric and Shape Memory Effects in the Mn2NiGa Heusler Alloy

Physics of the Solid State - The results of investigation of functional characteristics of the Mn2NiGa Heusler alloy prepared by argon-arc melting are presented. Its electric resistance,...