Lead-containing oxyhalide glass

New glass compositions in the PbO-PbCl₂-PbBr₂ system are synthesized and the region of vitrification is established. The temperature of sample vitrification is determined using the technique of differential-thermal analysis and the influence of the components on the temperature of vitrification has been studied. Infrared, Raman, and X-ray photoelectronic spectra are registered, suggestions about the glass structure are made, and the X-ray-phase analysis has been carried out. The density is measured and the refractive index of glass is estimated.     

Dynamic Modeling of an Active Damper

A dynamic model of the starting current of an active damper based on a magnetorheological elastomer is described, Experimental data for the damper are derived.     

Nitrogen alloying of the 12% Cr martensitic-ferritic steel

The influence of the nitrogen content on the structure and mechanical properties of heat and corrosion resistant 12% Cr martensitic-ferritic steel developed at the Central Research Institute of Structural Materials Prometey has been studied. Steel containing 0.061 wt % nitrogen possesses a high level of mechanical properties. The decrease in the nitrogen content to 0.017 wt % leads to an increase of structurally free ferrite fraction in the steel, a decrease in the density of dislocations, a decrease of structural dispersity and the absence of finely dispersed precipitates of niobium and vanadium nitrides and carbides. As a result, there is a decrease in the strength properties, especially in the heat resistance.     

The structure and activity of Pt6 particles in ZSM-5 type zeolites

Density functional theory was applied to investigate the nature of active sites formed by the interaction of a Pt₆ guest particle with the silicalite and H-form of ZSM-5 as the host zeolites. Interaction of metal cluster with silicalite shows a slight stabilization (36 kJ/mol) and formation of a negatively charged Pt entity. When a metal particle is arranged in the channel of H-form substantial stabilization (187 kJ/mol) and generation of an oxidized Pt₆H⁺ species are observed. The formation of an active site includes interaction between a platinum particle and an acid site accompanied by the suppression of zeolite acidity. The suggestion is made that the alkane transformation on supported platinum particles proceeds via metal–cyclobutane and metal–carbene intermediates and does not need the direct involvement of acid sites. The difference in catalytic behavior of the Pt₆/HZSM-5 and Pt₆/ZSM-5 systems is discussed.