Matrix Entries of Real Representations of the Groups O(3) and SO(3)

We indicate bases for spinor representations of the groups O(3), SO(3), and SU(2) in which the representation matrices are real-valued. The matrix entries in these bases are calculated. We describe the transformation of classical orthogonal harmonic polynomials in three-dimensional space by these matrix entries.     

Excitation of low-lying nuclear states by the ion line emission in femtosecond laser plasma

A scheme of nuclear excitation by the ionic X-ray lines in laser plasma using two femtosecond laser pulses is proposed. The first pulse produces plasma with a given degree of ionization, allowing the X-ray line energies of the target ions to be tuned to resonance with the nuclear transition, while the second pulse generates hot electrons that are necessary for X-ray generation.     

Phase Composition of Coatings Formed on Titanium in Borate Electrolyte by Microarch Oxidation

The effect of oxidation conditions, temperature and concentration of the electrolyte, and its transformation from the true to colloidal solution on the phase composition and electrical resistance of coatings was studied.     

Invariant operators and separation of residual stresses

We consider the equations of linear theory of elasticity in stresses for the threedimensional space. Solutions are decomposed into sums of stationary solutions not satisfying the compatibility condition (residual stresses) and nonstationary solutions satisfying the compatibility condition and hence represented through the displacements. The construction of this decomposition is reduced to solving a series of Poisson equations.     

Kinetics of the oxidative coupling of methane in the presence of model catalysts

The kinetics of the oxidative coupling of methane (OCM) in the presence of La/MgO and NaWMn/SiO₂ catalysts in a flow reactor at low reactant conversions was studied. It was found that, in spite of different compositions and properties of the test catalysts, the formation of ethane from methane and ethylene from ethane can be described within the framework of the Mars-van Krevelen redox model in both cases. The rate laws of side reactions, which lead to the formation of carbon oxides, are different from the rate laws of the target reactions of the conversion of methane into ethane and ethane into ethylene. The kinetic parameters required for the numerical simulation of the OCM process were determined for either of the catalysts.     

Kerr-Assisted Self-Compression of Mid-IR Femtosecond Laser Pulse in Dielectrics: Nonlinear-Medium Choice

We demonstrate an efficient method of mid-IR femtosecond-laser-pulse self-compression in transparent dielectrics based on a suitable selection of the parameters of the medium and laser radiation. We discuss the principle of selection of the nonlinear medium for ultrashort-pulse self-compression. We show that the proposed combination of the Kerr nonlinearity and negative group-velocity dispersion in a set of transparent dielectric crystals (CaF₂, BaF₂, YAG, etc.) provides a compression of the incident laser pulse to a 1–2 cycle pulse width.     

Supercontinuum generation under filamentation driven by intense femtosecond pulses in supercritical xenon and carbon dioxide

It is found that supercritical fluids are a unique source of multioctave supercontinuum radiation, which is generated upon filamentation of an intense femtosecond laser pulse. If the laser pulse power significantly exceeds the critical power of self-focusing, then a supercontinuum with a width of three and a half spectral octaves (from 350 to 2000 nm) is generated in supercritical xenon. The red wing of supercontinuum generated in supercritical carbon dioxide has the form of a plateau in the range from 1400 to 1900 nm, while the blue wing of the spectrum is almost completely attenuated.     

Enhanced laser induced K X-rays generation during microchannel formation inside the object positioned in air

The increasing of yield of X-rays more than two times from femtosecond laser plasma produced in the target microchannel positioned in air compared to the case from fresh target’s surface was registered and the angular dependence of output of X-rays was firstly observed.