Determination of boundary layers in the plane problem for three-layer strips. Part 2

In the first part of this paper, we considered the exact statement of the plane elasticity problem in displacements for strips made of various materials (problem A, an isotropic material; problem B, an orthotropic material with 2G12 √E1E2). Further, we stated and solved the boundary layer problem (the problem on a solution decaying away from the boundary) for a sandwich strip of regular structure consisting of isotropic layers (problem AA). In the present paper, we use the solution of the plane problem to consider the problem for sandwich strips of regular structure with isotropic face layers and orthotropic filler (problem AB). © Allerton Press, Inc., 2009

Determining the boundary layers in the plane problem for three-layer strips. Part 1

We propose an exact solution of the problem on a boundary layer (a stress-strain state decreasing away from the boundary) for three-layer strips (rods) whose layers are made of different materials. We use the asymptotic integration method to obtain boundary eigenfunctions and a characteristic equation for the parameter describing the boundary layer decay rate. We study how the middle layer material affects the boundary layer extent. © Allerton Press, Inc., 2008

Electric Field Effect Analysis of Thin PbTe films on high-epsilon SrTiO3 Substrate

Thin PbTe films (thickness 500 - 600 angstrom), deposited on SrTiO3, have been investigated by electric field effect (EFE). The high resistivity of such thin films warrants a high sensitivity of the EFE method. The SrTiO3 substrate serves as the dielectric layer in the Gate-Dielectric-PbTe structure. Due to the large dielectric constant of SrTiO3, particularly at low temperatures, the electric displacement D in the film reaches the high value of about 10^8 V/cm, and the EFE introduced charge into the PbTe film amounts to ~ 8 microC/cm2. The high D permits to measure the EFE resistance and Hall constant over a wide region of D, revealing the characteristic features of their D-dependence. An appropriate theoretical model has been formulated, showing that, for such films, one can measure the dependence of the Fermi level on D. In fact, we demonstrate that shifting the Fermi level across the gap by varying D, the density-of-states of the in-gape states can be mapped out. Our results show, that the PbTe layers studied, possess a mobility gap exceeding the gap of bulk PbTe.Comment: 27 pages, 12 figure

THE USE OF UNMANNED AERIAL VEHICLES (UAV) FOR LAND MANAGEMENT

The article is devoted to a comparative analysis of the use of unmanned aerial vehicles for solving problems of land management. Scientific work highlights the prospects for the use of unmanned aerial systems in the implementation of local monitoring and the need to take into account the possibility of using unmanned aerial systems of various types in making management decisions to ensure their maximum efficiency in the shortest possible time. Given problem is not sufficiently substantiated in the Ukrainian law and this can lead to the complication of the use of unmanned aerial vehicles, due to bureaucratic and corruption schemes as well as the negative impact on objects of special use regime

PROSPECTS FOR THE DEVELOPMENT OF TOURISM IN THE CONDITION OF DIGITAL TRANSFORMATION

Digital and innovative technologies can significantly increase the level of development of the tourism sector, improve the quality of services and increase the competitiveness of tourism enterprises

Steric structure of some tert-butyl aryl sulfones

Aryl is in a skewed position (φ{symbol}=73±13‡) in tert-butyl aryl sulfones. There are no significant changes in the conformation of the sulfone molecules when methyl is replaced by the tert-butyl radical. © 1982 Plenum Publishing Corporation