Preparation of thermoelectric materials based on higher manganese silicide

Rhenium-doped higher manganese silicide based materials have been prepared by hot pressing. It has been shown that the pressing temperature of the materials can be lowered by adding titanium as a reductant or by sonication during pressing. The average thermoelectric figure of merit of the materials in the temperature range 600–900 K is Z ≅ 0.7 × 10⁻³ K⁻¹.     

Recording high-diffraction-efficiency holograms on a photosemiconductor-liquid crystal structure

Experimental real-time holograms were recorded on a structure comprising a liquid crystal and a p-i-n-diode based on a hydrogenated amorphous silicon. The holograms offer unprecedented diffraction efficiency at acceptable spatial frequencies.     

Fire-resistant hydrocellulose fibres

Conclusions A comparative study of the reactivity of various types of hydrocellulose fibres in the reactions of graft copolymerization and ammonolysis has been carried out.The advantage of the fire-protective treatment of hydrocellulose with T-2 in the presence of urea has been demonstrated.Values of the activation energy of the thermal decomposition process of fire-protected hydrocellulose fibres prepared using various fireproofing agents have been calculated.Translated from Khimicheskie Volokna, No. 3, pp. 37–38, May–June, 1984.     

Transition probabilities for 5s-5p, 5p-5d, 4f-5d, and 5d-5f transitions in Ag-like ions with Z = 50-86

The wavelengths, electric dipole transition probabilities, and oscillator strengths are calculated for transitions between low-lying states (5s-5p, 5p-5d, 4f-5d, and 5d-5f) in the silver isoelectronic sequence (50 ? Z ? 86) using relativistic perturbation theory with a zero-approximation model potential. The results are compared with the corresponding data of the relativistic Hartree-Fock theory and the relativistic many-body perturbation theory. The results of these three theoretical approaches are compared with available experimental data for the level lifetimes. Possible reasons for some disagreements are discussed.     

Determining the degree of coal oxidation at PAO AKKhZ

Methods of assessing coal oxidation are compared. The method developed by the Soviet Institute of Mining and the Coal Chemistry Institute is most expedient. On that basis, a draft of the Ukrainian DSTU standard on determining the oxidation of coal has been formulated. The method has been successfully used in selecting the flotation agent for coal enrichment at PAO Avdeevskii Koksokhimicheskii Zavod (AKKhZ).     

Structure and magnetic properties of iron-rich Sm-Fe-(V,W)-Ga alloys

The phase composition of the iron-rich Sm-Fe-(V,W)-Ga alloys annealed at 1000 and/or 800°C and the effect of gallium on the magnetic properties of phases found in these alloys are studied. The tungsten and vanadium solubilities in the ternary phase Sm₂{Fe_{1 − y} (V,W) _y }₁₇ (with y ≤ 0.05) was determined. Both elements increase the Curie temperature of this compound but do not change the type of its anisotropy. Gallium was found to be an element stabilizing the Sm₂{Fe_{1 − y} (V,W) _y }₁₇ phase with the Th₂Zn₁₇-type structure; it increases the Curie temperature of the phase and changes the easy axis (EA) direction from the in-plane position to, first, a cone of easy axes and, then, the [0001] direction of the hexagonal lattice. An increase in the gallium content is accompanied by a widening of the homogeneity range of the phase at 1000°C. A phase of composition Sm₃(Fe,W)₂₉ with a monoclinic structure and lattice parameters a = 10.59 ?, b = 8.56 ?, c = 9.66 ?, and β = 97° was detected. Its Curie temperature is T _C = 185°C; the EA is parallel to the ‖[20$ \bar 1 $ \bar 1 ] direction. The gallium solubility in the Sm₃(Fe,W,Ga)₂₉ and Sm(Fe,W,Ga)₁₂ compounds was found to be very low; gallium increases their Curie temperatures.