Classification of Three-Dimensional Integrable Scalar Discrete Equations

We classify all integrable three-dimensional scalar discrete affine linear equations Q ₃ = 0 on an elementary cubic cell of the lattice . An equation Q ₃ = 0 is called integrable if it may be consistently imposed on all three-dimensional elementary faces of the lattice . Under the natural requirement of invariance of the equation under the action of the complete group of symmetries of the cube we prove that the only non-trivial (non-linearizable) integrable equation from this class is the well-known dBKP-system. SPT acknowledges partial financial support from a grant of Siberian Federal University (NM-project No 45.2007) and the RFBR grant 06-01-00814.     

Investigation of the mechanical properties of polymer surface layers using surface waves

It is possible to excite ultrasonic surface waves at the surface of polymer materials and to determine the dependence of the wave parameters on the mechanical properties of the surface. The nature of the variation of the surface wave characteristics with material, temperature, and the frequency of the exciting vibrations has been established.Mekhanika Polimerov, Vol. 3, No. 5, pp. 933–939, 1967     

On the calculation of repulsive interatomic interaction potentials by the statistical theory. Pairs of positive alkali metal ions and noble gas atoms

Calculations from first principles of the repulsive potentials of interaction between Li⁺, Na⁺ and K⁺ ions and noble gas atoms (R = He, Ne, Ar, Kr) were carried out within the framework of statistical perturbation theory with the electron densities for both atoms and ions taken from Hartree-Fock calculations for the ground state. The data presented in a graphical form for the 0.5-4 au range for the Li⁺ + R pairs reveal a good agreement with toth the recent experimental results and quantum mechanical calculations. The agreement with the available experimental data for the K⁺ + R pairs is likewise good. The data for the Na⁺ + R, K⁺ + R pairs in the 1–5 au range are presented in the form of tables since no quantum mechanical calculations for them are available. A discussion is given of the approximations used and of their evaluation, as well as of work by other authors on the calculation of interaction potential within the statistical model. It is shown that the model used by Gordon and Kim is nearly identical to the one employed by the first author of this paper previously.     

Estimation of the Fulfillment of the Local Thermodynamic Equilibrium Criterion for the Plasma Generated by Laser Pulses of Various Shapes at the Surface of a Solid Target

The results of experimental estimation of the fulfillment of the local thermodynamic equilibrium (LTE) criterion for the plasma generated by laser pulses of various duration at the surface of a solid target placed in a gaseous atmosphere at standard pressure are given in the present paper. The fulfillment of all the LTE criteria is demonstrated for an ensemble of neutral atoms contained in the plasma generated by a giant laser pulse or by a laser pulse whose complex shape represents several giant pulses against the background of free-running laser oscillations. The plasma excited by the radiation of a Nd : YAG laser with energy 0.4 J per pulse is examined. We have recorded a resonance broadening of atomic Al and Mg lines. This has allowed us to estimate the density of neutral atoms contained in a plasma plume.     

Mechanisms of broadening of emission lines of a laser-induced plasma generated on the surface of rigid targets

This article reports the results of an experimental investigation of the basic mechanisms that cause the broadening of emission lines of a laser-induced plasma generated on the surface of rigid targets in a gaseous atmosphere. The contribution of Stark and resonance mechanisms of emission-line broadening for the resonance doublet Al I 3s²3p²P_3/2,1/2-3s²4s²S_1/2 and triplet Mg I 3s3p³P _0,1,2 ⁰ -3s4s³S₁ is discussed. The concentrations of neutral Al atoms in the laser-induced plasma are evaluated by the magnitude of resonance line broadening. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 67, No. 2, pp. 234–237, March–April, 2000.     

Single- and double-electron charge transfer in collisions of α-particles with hydrogen molecules

Total, partial, and angular differential cross sections of single- and double-electron charge transfer in collisions between α-particles and hydrogen molecules in the ground state in the interval of collision energies from 3 to 80 keV have been calculated. New data for charge transfer cross sections can be used for simulations and spectroscopy of α-particles in thermonuclear diverter plasma of nuclear reactors.