Self-propagating high-temperature synthesis of (Ho1-xLax)2O3 nanopowders for magneto-optical ceramics.

Weakly agglomerated nanoparticles of (Ho1-xLax)2O3 solid solutions were synthesized with the help of a self-propagating high-temperature synthesis (SHS). The nanopowders were studied by a simultaneous thermal analysis (TG-DSC), X-ray diffraction (XRD), BET and FT-IR spectroscopy methods. Changes of the particles morphology after annealing at different temperatures and ball milling were investigated by a scanning electron microscopy (SEM) and a dynamic light scattering (DLS) method. It was found that annealing at a temperature of 900 °C in air and ball milling of the SHS nanopowders allow obtaining rounded shape particles with a mean diameter of about 20 nm and C-type cubic crystal structure. Up to 10 mol.% of the lanthana was shown to dissolve in the holmium oxide nanoparticles.

Magneto-optical Faraday effect in dysprosium oxide (Dy2O3) based ceramics obtained by vacuum sintering.

The method of self-propagating high-temperature synthesis of submicron powders with subsequent vacuum sintering was used to produce a series of optical ceramics based on dysprosium oxide (DyxY0.95-xLa0.05)2O3, where x=0.7, 0.85, and 0.9. The influence of ceramics composition on optical transmission of the obtained samples was investigated. The studied materials had several transparency windows in the visible 500-730 nm, near-IR 1900-2300 nm, and mid-IR 3500-7500 nm ranges. The dependence of the Verdet constant on wavelength in the 400-1940 nm range was measured for each ceramics composition, and analytical approximations were obtained. When Y and La dopants were used, the Verdet constant depended linearly on the concentration of Dy3+ ions, and its value in the visible wavelength range was about twice that of the analogous value for a terbium gallium garnet crystal. The high transmission and relatively high Verdet constant make the produced materials highly promising for fabricating Faraday devices for Tm3+ and Ho3+ lasers and for lasers emitting in the visible spectrum.

[Higher medical schools and medical institutions: feedback problems]. / Vuz i meditsinskie uchrezhdeniia: voprosy obratnoi sviazi.

Sociological study of graduates from Nizhny Novgorod State Medical Academy was carried out in 1997. The opinions of 199 physicians on the quality of training at the Academy, on employment and continuous education, etc., are analyzed. Proposals on improving the quality of staff training from a practitioners' viewpoint are collected and classified.