Transfer and Trapping of Resonance Radiation in a Two-Level System

Optics and Spectroscopy - The population kinetics of a two-level system has been theoretically investigated taking into account the transfer of spontaneous radiation under continuous optical...     

Analysis of electrode system for generation of high-power electrodynamic flow

A high-power electrodynamic flow in atmospheric air is numerically simulated and experimentally studied. An electrode system consisting of a cylindrical plasma emitter and a plane metal grid collector of ions is used to generate a flow with a speed of 2 m/s and a volume rate of 15 L/s.     

Contact Interactions between Polymeric Particles

The adhesion interaction between the particles of various amorphous glassy polymers and crystallizing poly(ethylene glycol) is investigated in the air and in the argon atmosphere. A strong effect of adsorption phenomena on the molecular attraction of polymers is disclosed.     

Change of surface properties of high-chromium cast iron under conditions of laser treatment and wear in a pellet stream

We investigate the influence of laser treatment on the formation of residual stresses relative to the changing structure-phase composition in the surface layers of high-chromium cast iron with 16% chromium. We show that appreciable tensile stresses are produced in the region of the laser action and that their distribution depends on whether the laser treatment was or was not accompanied by surface melting. The produced residual stresses are responsible for the formation of a large number of cracks. Preheating to 400°C lowers the level of the tensile residual stresses and prevents crack formation. A pellet stream acting on the surface produces cold-work hardening layers in which the tensile stresses change into compressive ones. The depth, hardness, and magnitude of the compressive residual stresses depend on the method used to work harden the cast iron and on the angle of attack of the pellet as it acts on the surface.Translation of Preprint No. 195, Lebedev Institute of Physics, Academy of Sciences of the USSR.     

Influence of laser treatment on the wear of friction surfaces of 40Cr steel

The friction wear of surfaces of 40Cr (40Khr) structural steel and 12Cr18Ni10Ti (12Kh18N10T) stainless steel is investigated. It is established, by comparison of the wear of initially annealed 40Cr steel after hardening by radiation from a CO₂ laser to various degrees of surface microhardness and separately after volume heat treatment, that the wear is due to fatigue in the entire range of microhardness, regardless of the dispersive properties of the structures. It is shown that the resistance to wear tends to increase with increase of the microhardness of the bearing surfaces. The dependence of the rate of wear on the surface microhardness is obtained. It is found that the wear process is accompanied by formation of a special structurally stressed state in the Saint-Venant region; this state is characterized by a constant hardness level independently of the preceding state of the material.Translation of Preprint No. 196, Lebedev Institute of Physics, Academy of Sciences, USSR, Moscow (1990).     

Thermodynamic characteristics of praseodymium in the gallium–aluminum eutectic melt

The Ga–Al eutectic melt saturated with praseodymium was studied in the temperature range 572–1076 K by electromotive force (emf) method relative to the reference electrode (In_L + PrIn₃, where L is the liquid phase) in a LiCl–KCl–CsCl eutectic electrolyte. The partial molar thermodynamic functions (enthalpy, entropy, and Gibbs energy) of praseo dymium in a Ga–Al eutectic melt were calculated. According to the emf measurements of the two-phase Pr–Ga–Al_L + intermetallic compound alloys equilibrated with the Ga–Al eutectic melt saturated with praseodymium, there are intermetallic compounds PrGa₆, PrGa₄, and Pr_0.22Ga_0.78(PrGa₂) in the temperature ranges 572–741, 741–883, and 883–1076 K, respectively.