Search

In the random phase approximation the imaginary part of the phonon polarization operator is calculated in the left vicinity of the Curie point as well as the renormalization of the sound velocity due to the spin-phonon interaction of exchange origin in a cubic ferrodielectric. [Russian Text Ignored].

The imaginary part of the phonon polarization operator and the renormalization of the sound velocity due to the spin-phonon interaction are calculated in a cubic ferrodielectric for large atomic spins in the spin-wave temperature region. [Russian Text Ignored].

The limits of applicability are established for the different decoupling procedures in the Green's function equations of the spin system of an Heisenberg ferromagnet. Es werden die Grenzen fur die Anwendbarkeit der verschiedenen Entkopplungsverfahren auf die Gleichungen fur die Greenschen Funktionen des Spinsystems eines Heisenbergschen Ferromagneten ermittelt.

A scratching cone can be considered as a knife edge with a negative leading angle; a conical indentor rises towards the surface of the metal on scratching with an unchanged normal load on account of work-hardening in the metal and of frictional forces, which have a component in opposition to the vertical load.

The work shows that the friction coefficient μ during slip of polycrystalline electrolytic corundum, single-crystal silicon carbide and sintered corundum over hardened ShKh15 steel, and the wear m in an electrolytic corundum test-piece according to slip speed have a low point at speeds close to 100 m/sec. A hypothetical explanation is given for this behavior of μ and m.

Dry friction of steel on steel at high pressures and sliding speeds takes place without any noticeable oxidation of the rubbing surfaces and is accompanied by intense seizing and wear. The products of wear are not oxidized and appear as shiny metal particles [1].