Asymptotical behavior of the variance of sums of random variables with random replacements

In this paper, we introduce a scheme of summation of independent random variables with random replacements. We consider a series of double arrays of identically distributed random variables that are row-wise independent, but such that neighboring rows contain a random common part of the repeating terms. By this-scheme we bscribe a model of strongly dependent noise. To investigate the sample mean of this noise, we consider the sum of random variables over the whole double array and its conditional variance with respect to replacements. For columns of the arrays we prove a covariance inequality. As a corollary of it, we demonstrate the law of large numbers for conditional variances. Bibliography: 4 titles. Translated fromZapiski Nauchnykh Seminarov POMI, Vol. 216, 1994, pp. 124–143. Translated by A. Sudakov.     

Analysis of the Magnetic Structure of the BiFeO<Subscript>3</Subscript> Multiferroic by Mössbauer Spectroscopy

Specific features of the magnetic structure of the BiFeO₃ multiferroic have been investigated by Mössbauer spectroscopy in the temperature range of 150–450 K. The temperature dependence of the anharmonicity parameter of the cycloidal spatial spin-modulated structure has been measured, and the magnetic anisotropy constant has been estimated.     

Relativistic effects of chlorine in 15N NMR chemical shifts of chlorine-containing amines

Russian Journal of Organic Chemistry - Quantum-chemical calculations by DFT method demonstrated that the accounting is necessary of the shielding by chlorine of nitrogen atom in practical...     

Mechanochemical treatment of maricite-type NaFePO4 for achieving high electrochemical performance

Journal of Solid State Electrochemistry - In order to satisfy a growing demand for energy storage devices and to create safer and less expensive batteries with high capacity, materials based on...     

Growing of Alkaline Earth Halide Scintillation Crystals and Their Optical Properties

Physics of the Solid State - The features of using the Bridgman method for growing alkaline earth halides crystals BaBrI, BaClI, and SrBrI are discussed. The results of the study of scintillation...     

Birfucation of solutions for convecttve flows of gas heated below in a wide range of pressure differences

Direct numerical modeling based on a net method is used to investigate the convective flow of a viscous compressible gas in a closed square region heated from below. The complete Navier-Stokes equations and some simplified models of the type of Boussinesq equations are used. The influence of the hydrostatic compressibility on the bifurcation of the solutions is investigated. A definition of the Rayleigh number that makes it possible to match results obtained using different models is proposed.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 163–166, May–June, 1993.     

Fokker-Planck operator for free-molecular,nonspherical, thermally nonequilibrium Brownian particles

The Fokker-Planck collision operator entering into the kinetic equation for the velocity distribution function of convex nonspherical rigid homogeneous Brownian particles in a traveling inhomogeneous monatomic gas is derived. The regime of flow past the particles is free-molecular, i.e., the characteristic particle dimensions are much smaller than the average free path of the gas molecules, the interaction between the particles and their effect on the gas phase can be neglected, and a specular-diffuse law of interaction between the molecules and the particle surface holds. The particle temperatures T _p are the same and differ from the local gas temperature T. Thermal nonequilibrium (T _p ≠ T) leads to violation of the well-known relations between the diffusion coefficients in the spaces of the translational and angular velocities and the coefficients of forces and moments exerted on a particle. The coefficients in the unknown operator are calculated for the particles in the form of bodies of revolution with longitudinal symmetry. Data characterizing the effect of the nonsphericity of the particles, i.e., spheroids and sphere-cylinders, on the degree of violation are given.     

Mössbauer Study of Magnetite Formation by Iron- and Sulfate-Reducing Bacteria

Hyperfine Interactions - Mössbauer investigations of the influence of physicochemical factors and the inert organic substances on the magnetite formation by thermophilic dissimilatory...     

Application of an implicit iterative difference scheme for the solution of nonstationary Navier-Stokes equations

An implicit iterative difference scheme of second-order accuracy in space and in time is proposed for numerical solution of nonstationary Navier—Stokes equations. The scheme has been applied to model a nonstationary axisymmetric flow in the near wake produced by injection through an annular nozzle from the tail of a supersonic body.Translated from Vychislitel'naya Matematika i Matematicheskoe Obespechenie EVM, pp. 216–231, 1985.     

The special features of the crystal structure and properties of oxides with mixed conductivity based on lanthanum gallate

The paper presents a review of works on the synthesis, structural composition effects, phase transitions, and electrical conductivity properties of multicomponent solid solutions based on heterosubstituted lanthanum gallate (La,A)(Ga,M)O_{3 ? y} . High-temperature phase transitions and structural and charge ordering effects were studied. The presence of iron cations in different valence states was proved; the relative contents of these cations depended on the x parameter and nonstoichiometry parameter y of the base composition. For M = Fe, antiferromagnetic ordering was observed; its temperature interval was determined by the concentration of iron cations in the high-spin state. The total conductivity was found to increase as the concentration of transition metal cations grew because of an increase in the electronic conductivity component. The data on structural parameters and dc and ac conductivity substantiated the conclusion that the highest ionic conductivity and permeability to oxygen were characteristic of iron-containing oxides. The results obtained are evidence that crystal chemical factors play a determining role in the formation of the ion-conducting properties of anion-deficient perovskite-like oxides.