Joint solubility of samarium and dysprosium in solid magnesium

The phase compositions of solid Mg–Sm–Dy alloys corresponding to the magnesium-corner region of the phase diagram are studied by optical and scanning electron microscopy, electrical resistivity measurements, and electron microprobe analysis. The obtained results allowed us to determine the joint solubility of samarium and dysprosium in solid magnesium at 500, 400, and 300°C; it decreases with decreasing temperature. The magnesium solid solution is found to be in equilibrium only with the Mg₄₁Sm₅ and Mg₂₄Dy₅ compounds, which are in equilibrium with the magnesium solid solution in the binary Mg–Sm and Mg–Dy systems.     

Structure and gas permeability of nanoporous metal oxide coatings produced by the alkoxide method

Peculiarities of the preparation of selective nanoporous metal oxide coatings on the surface of macroporous rutile support (pore size 0.1 μm and mixed aluminum and titanium oxides (pore size 0.05 μm) are presented. Gas selective coatings of empirical formula of P _x Ti_{1 ? 0.5x} O_{2 ± δ} with uniform distribution of nanosized pores have been obtained with the alkoxide method using titanium alkoxide and ettriol phosphite (precursor of the phosphorous-containing component) at their various total concentrations. Surface morphology of the obtained membranes has been investigated and major parameters of gas selective coatings have been determined. It has been shown that the dependences of the He, N₂, CO₂, and C₃H₈ gas permeability on temperature and pressure drop are consistent with the molecular regime of gas flow. The reproducible effect of permeability anisotropy of ～502?60% is observed when the integral vacuum method is used.     

Thermoelectric Properties of Nanocomposite Bi0.45Sb1.55Te2.985 Solid Solution with SiO2 Microparticles

Semiconductors - Nanocomposite thermoelectrics based on Bi0.45Sb1.55Te2.985 solid solution of p-type conductivity are fabricated by the hot pressing of nanopowders of this solid solution with the...     

Topological Surface States of Multicomponent Thermoelectrics Based on Bismuth Telluride

Semiconductors - The surface states of Dirac fermions in p-Bi2Te3, p-Bi2 –xSbxTe3 –ySey, and p-Bi2 –x–ySnxGeyTe3 thermoelectrics were studied and its topological...     

On the conduction-band structure of bismuth telluride: optical absorption data

The optical absorption spectra of n-Bi₂Te₃ in the range 40–300 meV are studied at room temperature in relation to the electron concentration and sample thickness in order to determine the parameters of the additional subband in the conduction band of Bi₂Te₃ and to clarify the possible effect of this subband on charge-carrier transport. It is shown that bismuth telluride is a direct-gap semiconductor with an additional subband in the conduction band. These data are consistent with the results of studies of quantum oscillations in n-Bi₂Te₃ in high magnetic fields at temperatures below 20 K.     

On the morphology of the interlayer surface and micro-Raman spectra of layered films in topological insulators based on bismuth telluride

Resonant micro-Raman spectra and the morphology of the interlayer Van der Waals surface are studied for layered thin films of n-Bi₂Te₃ and solid solutions based on Bi2Te3. It is found that the composition, thickness, surface morphology, and the method of obtaining films affect the relative intensity of Raman phonons, which are sensitive to the topological surface states of Dirac fermions.     

Definition,analysis and synthesis of goals in complex systems. Simulation models and methods

The problem of ensuring logically correct definition, analysis and synthesis of goals in complex systems and correct results of these procedures, viz. structures of goals and schemes of achieving goals, is stated. Models and methods that allow classifying the possible logical errors in the structures of goals and developing a human-machine system for analyzing and synthesizing goals are proposed.     

Topological Surface States of Dirac Fermions in n-Bi2Te3 –ySey Thermoelectrics

Semiconductors - In n-Bi2Te3 and n-Bi2Te3 –ySey thermoelectrics, the surface states of Dirac fermions of the interlayer Van der Waals surface (0001) are studied by scanning tunneling...     

Scanning Tunneling Microscopy in (Bi,Sb)2(Te,Se, S)3 Chalcogenide Thermoelectrics

Semiconductors - The morphology of the (0001) interlayer surface has been investigated by scanning tunneling microscopy in n-Bi1.6Sb0.4Te2.94Se0.06, n-Bi1.8Sb0.2Te2.82Se0.09S0.09,...