SHS of a superoxide in the Na-Fe-Y-O system

For the first time, complex oxide NaFeYO_{7 + x} was prepared by SHS (T _c = 750–1200 K, U = 1–4 mm/s) in the Na-Fe-Y-O system. Explored was the influence of reagents ratio on combustion limits for the mixtures under study. Combustion products were characterized by XRD, SEM, EDX, chemical analysis, and magnetic measurements. Single-phase NaFeYO_{7 + x} was obtained at an excess of sodium in green mixtures. To stabilize the product, the water-washing procedure was used just after synthesis. The synthesized material has a cubic crystal structure with a cell parameter close to that of sodium yttrate NaYO₂, it exhibited very weak magnetic properties, and overly-stoichiometric oxygen content. The product is heat resistant up to 450 K. The synthesized product is a new inorganic superoxide with good technological perspectives for use as a solid oxygen-containing material.     

Tribological characteristics of epoxy carbon-fiber-reinforced plastics modified by solution of polytetrafluorethylene telomers

The paper discusses technology for modifying antifriction epoxy carbon-fiber-reinforced plastics by applying tetrafluorethylene telomere film onto carbon tissue. The structure and mechanical and tribological characteristics of the modified material have been studied. The results of comparative tribotests of epoxy carbon-fiber-reinforced plastics UGET-URAL-T15R-EKHO-T₁₀₀ and UGET-URAL-T15R-EKHO-T₁₂₀ and basic material URAL-T15R-EKHO are presented. The tests were carried out using a block-on-roller arrangement in running water. For each material, analytical equations for calculating the coefficient of friction and wear rate depending on contact pressure are derived.     

Electrospray deposition as a method to fabricate functionally active protein films

Electrospray ionization is a routine method in MS analysis of proteins and other biopolymers. Deposition of the electrospray products onto a conductive electrode is suggested here as a means to manufacture functionally active protein films. Recovery of the specific hydrolytic activity of the electrosprayed alkaline phosphatase (AP) was used as a probe for preservation of protein intactness in the electrospray deposition (ESD). It was shown that protein inactivation upon ESD is highly dependent on voltage and current used. Humidity and the presence of protective substances in solution also affect the process. Complete preservation of the enzyme activity was observed when the ESD was performed at low current and humidity in the presence of disaccharides.     

Memory effect in stationary plasma thrusters of the SPD-MAG type

Experimental data on the working regime restoration (memory effect) after temporary switch-off in stationary plasma thrusters of the SPD-MAG type are presented. The character of changes in the parameters of thruster operation after switch-on depends on the initial regime and on the pause duration.     

Measurement and stabilization of the energy parameters of laser radiation using nonlinear optical effects

A new method is reported for the measurement, stabilization, and control of the energy parameters of laser radiation based on the optical rectification effect and the photogalvanic effect. It is proposed to use the same nonlinear optical crystal mounted inside a laser cavity for harmonic generation, as a voltage or current detector, and also as a modulator. A brief comparison is made with earlier methods. Pis’ma Zh. Tekh. Fiz. 24, 76–79 (May 26, 1998) Presented at the Joint Conference on Coherent and Nonlinear Optics, St. Petersburg, May 1995 (Presented prior to April 15, 1995 at Moscow State University)