Effect of ytterbium on anti-stokes luminescence of holmium at excitation in the 1.2-μm region

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 54, No. 5, pp. 778–783, May, 1991.     

Effect of the nanoparticle size of supported copper-containing catalysts on their activity in the selective oxidation of CO in an excess of H<Subscript>2</Subscript>

The catalytic properties of systems prepared by the supporting of CuO onto CeO₂, ZrO₂, and Zr_0.5Ce_0.5O₂ with particle sizes of 15–25 nm (nitrate pyrolysis (p)) and 5–6 nm (microemulsion method (me)) in the reaction of CO oxidation in an excess of H₂ were studied. In the latter case, the supports had an almost homogeneous surface and a small number of defects. The catalytic activity of (me) and (p) supports was low and almost the same, whereas the catalytic activity of CuO/(CeO₂, ZrO₂, and Zr_0.5Ce_0.5O₂)(me) samples was lower than that of CuO/(CeO₂ and ZrO₂)(p). The maximum CO conversion (∼100% at 125°C) was observed on 5% CuO/CeO₂ (p). The CO and CO₂ adsorption species on (p) and (me) catalysts were studied by TPD. Differences in the compositions of copper-containing centers on the surfaces of (p) and (me) systems were found using TPR. The nature of the active centers of CO oxidation and the effect of support crystallite size on the catalytic activity were considered.     

Experimental investigation of the resistance laws for gas flow in a low-porosity medium at high Reynolds numbers

The interphase interaction force at low porosity was studied experimentally. Two methods are proposed for calculating the specific surface area of pores and for obtaining approximation relations for the resistance force and the Cozeni-Carman constant which are valid in a wide range of values of the parameters of the flow and porous layer.Scientific-Research Institute of Applied Mathematics and Mechanics at Tomsk State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 4, pp. 101–109, April, 1993.     

Remarks on donor-acceptor interaction in molecules of nitrobenzyl compounds

Conclusions The groups YHg, CH₃ and R₂NCH₂ in the p-derivatives of nitrobenzene have very little effect on the spectra of the nitrobenzene compounds, while the R₂N group has a strong effect, and the YHgCH₂ occupies an intermediate position. This relates not only to the effect of the frequency and intensity of the infrared absorption bands of the nitro group and on the first intense long-wave band in the ultraviolet spectrum, but also to the sensitivity of these parameters to the effect of intermolecular reaction. It is possible that solvation of the YHgCH₂ group occurs, accompanied by an increase in its electron-donor capacity.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2010–2012, November, 1966.The authors wish to thank A. V. Dombrovskii and V. A Kalyavin for the graciously supplied compounds.     

Convective combustion analyzed on a viscoplastic model for a porous medium

A new model is proposed for the convective combustion of a porous fuel, which incorporates the deformation and dispersal of the porous matrix as well as the dissipative heating. Parametric studies have been made on the combustion of low-porosity and granulated charges. An experimental test agrees well with the model.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 96–103, August, 1992.     

Numerical investigation of self-organizing systems that arise in plastic information

Solutions of the equations of the evolution of the most popular self-organizing systems observed when a solid is deformed are investigated. The phase patterns for a “predator—prey” self-excited oscillatory system which arises during the evolution of a dislocation—disclination type pair, an autocatalytic system, formed by dislocation—vacancy type defects in a localized zone of plastic shear, and the self-organizing system described by the field of elastic stresses and strains for a solid with wave-type plastic deformation are described. Sumskii State University. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 3–8, June, 1996.