Voronezh State University

About: Voronezh State University is a education organization based out in Voronezh, Russia. It is known for research contribution in the topics: Silicon & Boundary value problem. The organization has 5166 authors who have published 6097 publications receiving 31680 citations. The organization is also known as: VSU & Voronezh University.

On the Spectral Properties of Differential Operators with Unbounded Operator Coefficients Determined by a Linear Relation

Abstract: Necessary and sufficient conditions for the invertibility and the Fredholm property of operators generated by a family of evolution operators and by the boundary conditions determined by a linear relation are obtained

Determining the Number of Radio Signals with Unknown Phases

Abstract: We have carried out the synthesis and analysis of the maximum likelihood and quasi-likelihood algorithms in order to determine the number of radio signals, introducing and calculating the abridged probability of error in the assessment of the number of signals as the quantitative characteristic for the performance evaluation of these algorithms. The achieved analytical results lead us to the comparison between the characteristics of maximum likelihood and quasi-likelihood algorithms in determining the number of signals. We also consider the possibility for the application of the quasi-likelihood algorithm for the determination of the number of radio signals with partially unknown initial phases.

Geochemical evolution of the banded iron formations of the Voronezh Crystalline Massif in the early Precambrian: Sources of matter and geochronological constraints

Abstract: The banded iron formations (BIFs) of the Voronezh Crystalline Massif occur at three stratigraphic levels: Mesoarchean, Neoarchean, and Paleoproterozoic. In comparison with Paleoproterozoic BIFs, the Archean BIFs are enriched in TiO2, Al2O3, Cr, Ni, and REEs. All the BIFs are characterized by positive Eu anomalies, absence of Ce anomalies, and predominance of HREEs over LREEs. The Paleoproterozoic BIFs show no evidence of clastic or hydrothermal contamination. The low Ni/Fe ratios indicate that the BIFs are younger than 2.7 Ga and their formation was followed by a sharp drop of the level of the mantle Ni supply. On the other hand, very low (<1 ppm) U contents indicate the upper age of iron accumulation—no later than the Great Oxidation Event of ~2.47 Ga.

Perturbative calculation of the triply differential cross section for photo-double-ionization of He

Abstract: Single-photon, two-electron ionization of He is analysed, taking into account electron correlation using lowest-order perturbation theory and including all individual electron angular momenta in the final two-electron continuum. Perturbative account of electron correlation in the final state, which describes the so-called TS-1 mechanism of double photoionization, combined with a variational account of electron screening, is found to provide results for the triply differential cross section at an excess energy of 20 eV that are in excellent agreement with both absolute experimental data and results of non-perturbative calculations, for all kinematics of the process in which the TS-1 mechanism is expected to dominate.