Lanthanides in phosphates with the structure of whitlockite mineral [analog of β-Ca3(PO4)2]

Data on phosphates with the structure of biogenic whitlockite mineral [analog of low-temperature modification of β-Ca₃(PO₄)₂] were analyzed. The possibility of isomorphic substitution of cations in phosphates with whitlockite structure was evaluated and formation of solid solutions of various compositions involving elements in oxidations states 1+, 2+, 3+, and 4+, including lanthanides and other elements and isotopes occurring in wastes from radiochemical plants, was studied. Phosphates of Ca, Mg, and lanthanides (Sm, Eu, Gd) were prepared by the sol-gel procedure, and their thermal, thermomechanical (thermal expansion), and hydrolytic properties were determined. The results of hydrothermal and thermal experiments were compared with published data for calcium phosphate and other matrices for immobilization of radioactive wastes (RAW).     

Mechanochemical synthesis of the low-temperature (B20) phase of FeGe

We have investigated solid-state reactions in an equiatomic mixture of Fe and Ge powders during ball milling in a water-cooled high-energy mill under an argon atmosphere. The mechanical alloying products have been characterized by x-ray diffraction, Mössbauer spectroscopy, and calorimetry. The observed sequence of phase formation correlates with the thermodynamic properties of the iron germanides involved. The alloy prepared by ball milling for 2 h consists entirely of nanocrystallites (?15 nm) of the low-temperature, stable, cubic (B20) phase of FeGe.     

Thermodynamics of lutetium uranosilicate

The standard enthalpy of formation of crystalline Lu(HSiUO₆)₃ · 10H₂O at 298.15 K, ?10668.0±16.0 kJ mol^?1, and the standard enthalpy of its dehydration were determined by reaction calorimetry. The heat capacity of this compound in the range 80–300 K was measured by adiabatic vacuum calorimetry, and its thermodynamic functions were calculated. The standard entropy of formation at 298.15 K is ?3812.9±1.2 J mol^?1 K^?1, and the standard Gibbs energy of formation at 298.15 K, ?9531.0±16.5 kJ mol^?1. The standard thermodynamic functions of the reactions of the synthesis of lutetium uranosilicate were calculated and discussed.     

Inversion of the electron energy distribution in hollow-cathode glow discharge in nitrogen-sulfur hexafluoride gas mixture

The electron energy distribution function (EDF) in a hollow-cathode glow discharge in nitrogen-sulfur hexafluoride (N₂-SF₆) gas mixture has been studied by experimental and theoretical methods. On adding a small amount of SF₆ to N₂, the density of electrons in the energy interval (2−4 eV) of the EDF inversion increases by approximately one order of magnitude.     

Ionization kinetics in a supersonic xenon plasma flow entering electric field

We have studied xenon plasma moving in a supersonic diffuser in external electric and magnetic fields. The main physical parameters of the plasma (electron temperature and density) were determined using specially developed methods based on the theory of continuous optical emission from inert gas atoms. These experimental data are compared to the results of theoretical calculations. Based on an analysis of the results of spectroscopic measurements, a mechanism of plasma ionization is established which is capable of maintaining a high degree of ionization in the supersonic xenon plasma flow.     

Chromatographic method of determining oxygenates in commercial gasolines

The analysis conditions required to make a quantitative determination of ten oxygenates in different commercial gasolines are determined using a Kristall 5000.2 chromatograph manufactured by the Special Design Office Khromatek JSC.     

Various methods for the deoxidation of a Cr-Ni-Mo-V steel during out-of-furnace treatment and their effect on the formation of nonmetallic inclusions

The effect of various methods of deoxidation during out-of-furnace treatment on the content and composition of nonmetallic inclusions in 15Kh2NMFA steel measured after out-of-furnace treatment and in forged pieces made from large ingots of this steel is studied.