Социальная активность современной молодежи: экологический аспект

This article deals with the problems of development of social activity of youth. Identified and justified the need for the development of environmental competence. The definition of environmental social activity. On the basis of the studyrevealed the main areas of the environmental activities of today's youthВ статье рассмотрены проблемы развития социальной активности молодежи. Выявлена и обоснована необходимость развития экологической компетентности. Дано определение экологической социальной активности. На основе проведенного исследования выявлены основные направления экологической деятельности современной молодеж

Tangling clustering of inertial particles in stably stratified turbulence

We have predicted theoretically and detected in laboratory experiments a new type of particle clustering (tangling clustering of inertial particles) in a stably stratified turbulence with imposed mean vertical temperature gradient. In this stratified turbulence a spatial distribution of the mean particle number density is nonuniform due to the phenomenon of turbulent thermal diffusion, that results in formation of a gradient of the mean particle number density, \nabla N, and generation of fluctuations of the particle number density by tangling of the gradient, \nabla N, by velocity fluctuations. The mean temperature gradient, \nabla T, produces the temperature fluctuations by tangling of the gradient, \nabla T, by velocity fluctuations. These fluctuations increase the rate of formation of the particle clusters in small scales. In the laboratory stratified turbulence this tangling clustering is much more effective than a pure inertial clustering that has been observed in isothermal turbulence. In particular, in our experiments in oscillating grid isothermal turbulence in air without imposed mean temperature gradient, the inertial clustering is very weak for solid particles with the diameter 10 microns and Reynolds numbers Re =250. Our theoretical predictions are in a good agreement with the obtained experimental results.Comment: 16 pages, 4 figures, REVTEX4, revised versio

Cascades on a class of clustered random networks

peer-reviewedWe present an analytical approach to determining the expected cascade size in a broad range of dynamical models on the class of random networks with arbitrary degree distribution and nonzero clustering introduced previously in [M.E.J. Newman, Phys. Rev. Lett. 103, 058701 (2009)]. A condition for the existence of global cascades is derived as well as a general criterion that determines whether increasing the level of clustering will increase, or decrease, the expected cascade size. Applications, examples of which are provided, include site percolation, bond percolation, and Watts' threshold model; in all cases analytical results give excellent agreement with numerical simulations.PUBLISHEDpeer-reviewe

Spin-orbit interaction in three-dimensionally bounded semiconductor nanostructures

The structural inversion asymmetry-induced spin-orbit interaction of conduction band electrons in zinc-blende and wurtzite semiconductor structures is analysed allowing for a three-dimensional (3D) character of the external electric field and variation of the chemical composition. The interaction, taking into account all remote bands perturbatively, is presented with two contributions: a heterointerface term and a term caused by the external electric field. They have generally comparable strength and can be written in a unified manner only for 2D systems, where they can partially cancel each other. For quantum wires and dots composed of wurtzite semiconductors new terms appear, absent in zinc-blende structures, which acquire the standard Rashba form in 2D systems.Comment: 18 pages, 1 figur

Precision determination of band offsets in strained InGaAs/GaAs quantum wells by C-V-profiling and Schroedinger-Poisson self-consistent simulation

The results of measurements and numerical simulation of charge carrier distribution and energy states in strained quantum wells In_xGa_{1-x}As/GaAs (0.06 < x < 0.29) by C-V-profiling are presented. Precise values of conduction band offsets for these pseudomorphic QWs have been obtained by means of self-consistent solution of Schroedinger and Poisson equations and following fitting to experimental data. For the conduction band offsets in strained In_xGa_{1-x}As/GaAs - QWs the expression DE_C(x) = 0.814x - 0.21x^2 has been obtained.Comment: 9 pages, 12 figures, RevTeX