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.

Photocatalytically Active Zinc Oxide and Titanium Dioxide Nanoparticles in Clonal Micropropagation of Plants: Prospects

Abstract: The search for effective and nontoxic sterilization drugs for plants against common phytopathogenic microorganisms is a major challenge to improve the biotechnology of plant clonal micropropagation. An analysis of 92 studies that describe the potential use of ZnO and TiO2 nanoparticles as antimicrobial agents in biotechnology showed that their biological effects depend on several factors: photocatalytic activity, particle size, concentration, morphology, and surface modification. The mechanisms of toxicity, among which the primary one is generation of reactive oxygen species leading to oxidative stress, are also due to these factors. The data describing the direct influence of ZnO and TiO2 nanoparticles on plants, however, are contradictory, which is probably because of the various particle shapes and sizes, their concentrations, and the species characteristics of the plants studied. These studies have confirmed that photocatalytically active ZnO and TiO2 nanoparticles may be used as bactericidal and fungicidal drugs for sterilization of explants during clonal micropropagation of plants, while taking into account the possible phytotoxicity of these particles.

On the Riesz Constants for Systems of Integer Translates

Abstract: In this paper, one-parameter families of integer translates of the Gaussian and Lorentz functions are studied. For a Lorentz function, we obtain formulas for the coefficients of the series defining node functions and show that the limit value of node functions is given by a sample function. For systems of translates generated by the Gaussian and Lorentz functions as well as by the node functions related to them, we obtain explicit expressions for the Riesz constants and study the parameter-dependent behavior of these constants. While proving some of the results of this paper, we establish the monotonicity of a special ratio of two Jacobi theta functions, a fact which is of interest in itself.

Mathematical modelling of light dependent microorganisms cultivation in countercurrent film reactor

Abstract: The kinetic parameters of the pseudo-continuous cultivation of green microalgae in the film photobioreactor with countercurrent flows of gas and liquid phases and equipped with spirals on the internal surface of quartz tubes have ben studied. A mathematical model of mass transfer during microalgae cultivation in a film photobioreactor has been developed. The model includes a kinetic equation that considers the effect of the conditions of the cultivation of microalgae populations and cells interactions. A method has been developed for solving equations of the model that uses the Galerkin combination and the finite-element methods.

Anti-Stokes-enhanced tunneling ionization of molecules

Abstract: We consider the influence of vibrational motion of nuclei on the tunneling ionization of a molecule in a strong light field. Unlike the molecular Ammosov-Delone-Krainov (MO-ADK) model [X. M. Tong et al., Phys. Rev. A 66, 033402 (2002)], the Franck-Condon factors that take into consideration the quantization of nuclear vibrations are introduced in the theory. Modification of the vibrational motion of nuclei by the external field leads to the time-dependent constant in the asymptotic form of the electronic wave function. This in turn leads to a more significant modification of the Keldysh theory for the tunnel effect in molecules as compared to the MO-ADK model. We take into account the possibility of vibrational quantum numbers changing in a neutral molecule and in a molecular ion in the process of the tunneling ionization, which in principle enables one to get molecular ions of a certain isotopic composition if the vibrational states of the neutral molecules with this isotopic composition are pumped before ionization. We present numerical results illustrating this possibility for the isotopes of a hydrogen molecule.