Phase formation in the BaB<Subscript>2</Subscript>O<Subscript>4</Subscript>-NaBO<Subscript>2</Subscript>-MBO<Subscript>3</Subscript> (M = Sc,La, Y) system and new orthoborate ScBaNa(BO<Subscript>3</Subscript>)<Subscript>2</Subscript>

Phase formation in the BaB₂O₄-NaBO₂-MBO₃ (M = Sc, La, Y) system was studied using solid-phase synthesis, visual polythermal analysis, and spontaneous crystallization. This system was shown to be suitable for growing LaBO₃. A new compound, ScBaNa(BO₃)₂, was obtained (trigonal crystal system; space group R \(\bar 3\) unit cell parameters: a = 5.239(1) Å, c = 34.591(1) Å, and V = 822.38(4) ų).     

Convective Flows in a Melt During Crystal Growth under Periodic Temperature Field Conditions

The results of an analysis of thermo-gravitational convection in Czochralski single-crystal growth from a melt under periodic temperature field conditions are presented. The numerical modeling is based on solving the unsteady 3-D Navier-Stokes and heat conduction equations in the Boussinesq approximation. It is shown that using different heating regimes for the crystal medium provides additional opportunities for controlling heat and mass transfer.     

TPD studies of ethylene adsorption over platinum black

TPD studies of ethylene adsorption over Pt-blacks of various dispersity with and without hydrogen at 298 K indicate that the metal dispersity and the presence of hydrogen on the surface influence the direction of hydrocarbon transformation on platinum.

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298 Pt- . .

     

Growth of lithium triborate (LiB3O5) single crystals in the Li2O-B2O3-MoO3 system

Solubility curves are plotted and optimal solvents for growing lithium triborate (LiB₃O₅) single crystals are determined. The crystallization range of this compound in the Li₂O-B₂O₃-MoO₃ system is refined. The molybdenum content in the crystals grown is analyzed.     

Structural and vibrational properties of PVT grown Bi2Te3 microcrystals

High-quality Bi₂Te₃ microcrystals have been grown by physical vapor transport (PVT) method without using a foreign transport agent. The microcrystals grown under optimal temperature gradient are well facetted and they have dimensions up to ～100 μm. The phase composition of grown crystals has been identified by X-ray single crystal structure analysis in space group R3?m, a=4.3896(2) Å, b=30.5019(10) Å, Z=3 (R=0.0271). Raman microspectrometry has been used to describe the vibration parameters of Bi₂Te₃ microcrystals. The FWHM parameters obtained for representative Raman lines at 61 cm^?1 and 101 cm^?1 are as low as 3.5 cm^?1 and 4.5 cm^?1, respectively.     

Modulation of the Dirac Point Band Gap in the Antiferromagnetic Topological Insulator MnBi2Te4 due to the Surface Potential Gradient Change

Journal of Experimental and Theoretical Physics - The possibility of significant modulation of the band gap open at the Dirac point (DP) in the range from 15 to 55 meV for different samples of the...     

Impact of Co Atoms on the Electronic Structure of Bi2Te3 and MnBi2Te4 Topological Insulators

Journal of Experimental and Theoretical Physics - This work is devoted to an experimental investigation of the electronic structure of the surface of topological insulators of various stoichiometry...     

Qualitative and Numerical Analysis of a Cosmological Model Based on an Asymmetric Scalar Doublet with Minimal Connections. III. Multiply-Connected Factor and Character of the Singular Points

Russian Physics Journal - On the basis of a qualitative and numerical analysis of a cosmological model based on an asymmetric scalar doublet of nonlinear, minimally interacting scalar fields, both...     

Qualitative and Numerical Analysis of a Cosmological Model Based on an Asymmetric Scalar Doublet with Minimal Couplings. II. Numerical Modeling of Phase Trajectories

Russian Physics Journal - With the help of our own software package DifEqTools, numerical modeling of the cosmological evolution of a system consisting of an asymmetric scalar doublet of nonlinear,...