[en] Some methods of physico-chemical analysis have been applied to study As₂S₃-CeS and As₂S₃-Ce₂S systems; their T-x diagrams are plotted. Boundaries of the solubility range are determined based on the initial components. Compounds of the compositions CeAs₄S₇, CeAs₃S₆ (melting congruently) CeAsS₃, CeAs₂S₄ (formed by peritectic reactions) are found

[en] The analysis of up-to-date situation in development of deposit is spent. It is shown that use the constantly working models allows to adequately describe a real condition of research objects, to reflect its geological and physical peculiarities, to take into account vast variety of the initial information with various degree of detail, to adequately describe a wide range of systems under development, boundary conditions in wells, modern technologies, to carry out the detailed all-round analysis of calculation results and choose optimum variant of development. (author)

[en] Method for definition of optimal bottom pressure value for exploring wells is supposed on the base of standard mathematical model. (author)

[en] State diagram of As₂S₃-Yb₂S₃ system was constructed on the basis of the data obtained by physico-chemical methods. The compound of YbAsS₃ composition was revealed in the system and the boundary of glass formation region on As₂S₃ base was determined

[en] The method of chemical transport reaction was applied to grow YbAs₄S₇ and Yb₃As₄S₉ monocrystals. The chemical analysis has shown correspondence of the formulae and compositions. The crystal system is determined, parameters of the crystal lattice are calculated. It is stated that YbAs₄S₇ is crystallized in the cubic and Yb₃As₄S₉- in the rhombic crystal systems with the following lattice parameters respectively: a=10.25; a=16.97; b=24.23 and c=4.03 A. The prepared monocrystals are stable in the air; they are well dissolved in the nitric acid and in alkali

[en] Full text: The effect of gamma irradiation on the structure and properties of ferro-, piezo- and pyroelectric materials are interest for extending their application fields in new active electrical elements. Gamma irradiation of perovskite (ABO₃) ceramic materials, such as barium titanate leads to the formation of stable defects, e.g., atomic displacements, or increases their lattice parameters. The objective of this work was to study the effect of gamma irradiation on the structure and ferroelectric properties of (1-x) Ba_1,65Sr_3,35Nb₁₀O₃₀(BSN) - x Ba₄Na₂ Nb₁₀O₃₀ (BNN) solid solutions, which are known to have the tetragonal tungsten bronze (TTB) structure. The high-density specimens were prepared by solid state reactions method and hot-pressing technique. The quality of the ceramics have been evaluated by the density (95-99% to theoretical) and by the microstructure size of the grain is 4-15 μm. The lattice parameters and symmetry were determined by powder X-ray diffraction (DRON-3.0 diffractometer, Ni-filtered CuK_α -radiation). The samples were irradiated in a ⁶⁰Co gamma source (RRhM-γ -30 or K-25 unit) at a gamma dose rate of 2,3 ·10⁴Gy/h. The dose was evaluated by the ferriferons sulfate method. After irradiation, the samples were stored for 45 day (to rule out post effects) and then poled with an electric field of 35 kV/cm at 400 K for 25 min. There are the composition and temperature dependences dielectric permeability (ε) and dielectric loss (tanδ) before and after gamma irradiation: 5·10⁵Gy; 10 ·10⁵Gy; 10 ·10⁶Gy of all compositions of the solid solutions BSN-BNN. With increasing gamma dose decreases monotonically. The lowest tanδ is observed at a gamma dose D=(8-10) ·10⁵Gy. At higher doses, tanδ increases; the curve of composition dependencies of the Curie temperatures T_c after gamma irradiation of 10 ·10⁶Gy is falling down. Similar results were reported for K₂Sr₄Nb₁₀O₃₀ - K₆Li₄Nb₁₀O₃₀, and were interpreted as due to the increase in radiation-induced conductivity and accumulation of radiation-induced defects [1]

[en] Methods of phisico-chemical analysis are used to study Yb(Sm)-As systems, their phase diagrams are plotted. YbAs, Yb₄As₃, SmAs compounds, melting with an open maximum, as well as Yb₅As compounds formed by peritectic reaction are detected

[en] The problem aimed at preparation of the films of As₂S₃-Yb system, at studying their substructure depending on condensation conditions and defining noncrystallinity region of this system in the film state, is formulated. It is shown that in representative samples of As₂S₃-Yb system the vitrification region is extended up to 7 at.% Yb, in the films noncrystallinity region is extended up to 30 at.% Yb. With up to 30 at.% increase of ytterbium amount in initial alloys a tendency to crystallization in amorphous condensate structure is noticed. In evaporation of As₂S₃ + 40 at.% Yb and As₂S₃ + 50 at.% Yb, unknown in the film state YbAs₂S₄, Yb₃As₄S₉ and YbAs₄S₇ phases are prepared, and the latter is formed in case of As₂S₃ + 50 at.% Yb alloy at small evaporation rates (∼10 A/s). Substructure of As₂S₃ + 50 at.% Yb alloy prepared condensate is more dependent on evaporation rate than in evaporation of As₂S₃ + 40 at.% Yb alloy. In this case, evaporation rates being ∼ 100 A/s, the condensate has a polycrystal structure, and at small rates of ∼ 10 A/c, condensate structure is primarily blocked

[en] On the base development of operation calculus for the computer simulation of transient processes in complex electrical chains with concentrated parameters

[en] Methods of physico-chemical analysis are used to study the nature of chemical interaction in the As₂S₃-YbS system. It is found that the boundary of glass formation range achieves 12 mol.% YbS. The existence of three compounds of YbAs₄S₇, YbAs₂S₄ and Yb₃As₄S₉ composition is found. Solubility on the basis of As₂S₃ is 0.8 mol.% at 298 K