The research of influence of periodical signal discontinuity on spectrum form is considered in the article. The numerical modeling of the system of discontinuous signals is performed. The spectrum of the system built from time discreet sampling is analyzed. The plots of the sample correlation coefficient between spectrums of continuous and discontinues signals are shown in the article. The research is needed for the development of digital measuring system for quartz plates frequency detecting.
Keywords: amplitude signal spectrum, discontinuous signal, quartz plates
A scheme of the experimental setup of the jet air temperature measurement. Experimental results confirm the dependence of the frequency stabilnost pneumatic signal from the flow temperature with a large number of measurements.
Keywords: pneumatics, temperature, piezo, airflow, sensor stuyny
In article the description of models of adaptive management outlining the content electronic courses. Model based on the analysis of factor run content element and the factor of time interacting with the content element CEMA (classifiers events - management analyzer) for calculating an objective indicator of course studying result of user to send a learning management system (LMS). A model of the DCG (dynamic content generation) to localize errors in the develop electronic courses and to the human factor in learning process. Proposed criteria and shown one model implementation AMLM (adaptive management e-learning materials). Results of the study found use in educational institutions and commercial enterprises involved in the introduction of new technologies and improve efficiency in e-learning. Organizations interested in the development of services provided by e-learning and stimulating economic benefits will find helpful many aspects of this work for planning strategies for education and training of personnel companies-customers, students and the public.
Keywords: education, e-learning, Learning Management System, electronic learning course, models of adaptive management outlining of content
The results of computational experiments to determine the characteristics of the porous piezoelectric ceramics based on the methodology, including the effective modules method, simulations of representative volumes on a simple random method and the method of Witten-Sander, finite element method to solve static piezoelectric problems for heterogeneous composite media and the accounting of inhomogeneous polarization near the pores are presented. A comparison of the results of computer simulation with the known experimental data for the porous material PZT-4 and its analogs is realized. It is concluded that the accounting of inhomogeneous polarization in the vicinity of porous provide the better agreement between numerical results and large number of known experimental data. Thus, for most effective constants the smallest errors are obtained for a representative volume of the porous piezoelectric material, constructed by Witten-Sander method.
Keywords: piezocomposite, porous piezoelectric ceramics, inhomogeneous polarization, mathematical modelling, models of representative volumes, finite element method, effective moduli
The article describes the method of constructing acoustic microblower based on piezoelectric device. The article shows the main problems in cooling systems for microelectronics and describes the general construction, which allows you to bypass these disad
Keywords: microblower, micro-pump, piezoelectric device, airflow, acoustic
The problem of manufacturing technology heterostructures pezofaza - metal considered in the article. Complexity consists in the fact that during the removal of the polymer in the system at low temperatures are formed porous layers, formed powders separated metal layers, having island macrostructure. One way to solve the problem - reducing the firing temperature heterostructures. Proposed to decrease the sintering temperature by using of functionally active glass-phases. Reducing the sintering temperature of products also allows to replace platinum electrodes inexpensive silver-based alloys. Obtained by solid state reaction method of piezoceramic material has a low sintering temperature (980 ° C) and high electrical parameters. Found that not only the proportion of the vitreous mass, but also their qualitative influence on the properties of piezomaterials
Keywords: heterostructure glass phase, the sintering temperature, porosity, ferroelectric phase
Piezoelectric ceramics on the basis of the phase of (1-x) PbTiO3-xPbZrO3 is the basis of most high-performance piezoelectric materials. Electrophysical and mechanical properties of these materials can vary widely in different ways. Traditional methods include changes in composition within the morphotropic region and doping. Now is the study of the influence of topical makrolegirovaniya the material properties of the PZT system. As a model system was selected phase of the PZT system, the compositions of which MO belong, one of which contains a dopant in the sublattice (A) and another - in the sublattice dopants (B). The studies established that one of the effective ways of varying the parameters piezomaterials may be the formation of solid solutions on the basis of two or more piezoelectric phases having different combinations of electrical parameters
Keywords: Piezoelectric ceramics, doping, kombinorovanie, pezofaza, piezo
In this article authors give information about problem of fiber-optical communication lines thermal-electric degradation and its consequences and study main reasons and factors which have an influence upon the degree of thermal-electric degradation. Possible and the most promising research ways are examined in this subject area; they let not only study this subject of fiber-optical communication lines thermal-electric degradation in detail but to solve this problem in whole.
Keywords: electromagnetic field, thermal-electric degradation, fiber-optical communication lines, FOC-cored static wire, kevlar, electrified railway
Information about authors of issue №1 (2011)