Unitary Representations of the Wigner Group ISL(2, ℂ) and A Two-Spinor Description of Massive Particles With An Arbitrary Spin

Based on Wigner unitary representations for the covering group ISL(2,?) of the Poincaré group, we obtain spin-tensor wave functions of free massive particles with an arbitrary spin that satisfy the Dirac–Pauli–Fierz equations. In the framework of a two-spinor formalism, we construct spin-polarization vectors and obtain conditions that fix the corresponding density matrices (the Behrends–Fronsdal projection operators) determining the numerators in the propagators of the fields of such particles. Using these conditions, we find explicit expressions for the particle density matrices with integer (Behrends–Fronsdal projection operators) and half-integer spin. We obtain a generalization of the Behrends–Fronsdal projection operators to the case of an arbitrary number D of space–time dimensions.     

Numerical analysis of vortex dynamics and unsteady turbulent heat transfer in lid-driven square cavity

Based on the solution of unsteady Reynolds equations (URANS) closed with the aid of differential equations for shear stresses transport (MSST), the evolution of the vortex structure in a square cavity with a moving lid and an unsteady turbulent heat transfer in the air medium are computed while maintaining constant temperatures of the hot moving and cold motionless walls (Re = 5·10⁴). The phases of the development of dynamic and thermal processes are analyzed.     

Coumarins of three species of the genusHaplophyllum

The results are given of an investigation of three species of the genusHaplophyllum: H. villosum, H. kowalenskyi, andH. tenue, fromwhich five substances of coumarin nature have been isolated. Of them, two substances (I and II) have been identified as scopoletin and lomatin isovalerate, respectively, while suitable structures have been established for the new compounds tenuidin, villosin, and tenudiol. It has been shown that the coumarin composition of the plants changes with the growth site.     

Synthesis and characterization of tetraphenylphosphonium salts of N-phosphorylated thioureas and bis-thioureas

Russian Chemical Bulletin - Tetraphenylphosphonium salts of N-phosphorylated thioureas and bio-thioureas were synthesized by the reactions of their sodium salts with PPh4Br in 96% aqueous EtOH. The...     

Peculiarities of the Crystal Structure and Texture of Isotropic and Anisotropic Polycrystalline Hexagonal Ferrites BaFe12O19 Synthesized by Radiation-Thermal Sintering

Russian Microelectronics - In this work the crystal structure and texture of isotropic and anisotropic polycrystalline hexagonal ferrites BaFe12O19 obtained by the method of radiation-thermal...     

Ohmic Contacts to CVD Diamond with Boron-Doped Delta Layers

Semiconductors - Various methods for the formation of ohmic contacts to boron-doped δ layers in CVD-diamond epitaxial structures are investigated. In the first variant, an additional thin...