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  • Ferroalloy piezoceramic material based on PZT, electrophysical and mechanical properties in a wide temperature range

    The electrophysical and mechanical properties of a piezoceramic material based on CTS are investigated. A number of features in the behavior of the electrophysical properties of the material in the temperature range located significantly below the low-frequency (1 kHz) maximum of the dielectric constant T_m = 160℃ have been revealed. The obtained results indicate the proximity of the studied material to ferroelectric relaxors, in particular, the low coercive field E_c~5 kVcmcm, the significant dependence of T_m on the frequency and amplitude of the measuring field, as well as the behavior of the velocity of longitudinal ultrasonic waves in this ceramic. It is shown that the elastic properties of this material are very close to ferroelectric relaxors, having a high malleability in a very wide temperature range. At the same time, the squareness of the polarization loops at relatively low temperatures indicates the manifestation of the classical properties of the ferroelectric during the polarization switching processes, and not the "freezing" processes characteristic of ferroelectric relaxors. From the results obtained, it can be established that this composition will be promising for use in the actuators of adaptive optics systems and precision positioning devices due to the high values of piezomodules.

    Keywords: PZT system, ferroalloy ceramics, dispersion, polarization, elastic properties, blurred phase transitions, curie temperature, depolarization temperature, ferroelectric relaxor, rhombohedral phase, tetragonal phase

  • Influence of the method of grinding the charge on the electrophysical parameters of the piezoceramic material ZTBS-3

    Piezoceramics based on the lead zirconate-titanate (PZT) system is the basis of most transducers operating on the piezoelectric effect and are used in various electronic devices operating in the sections of electrical and hydroacoustics, ultrasonic technology, etc. In turn, piezoceramic materials created in the last century have substantially exhausted their potential for use in modern devices, and it is rather difficult to develop new compositions and is not economically efficient. In connection with the above, an urgent task is to find modern ways to increase the parameters of piezoceramic materials.

    Keywords: piezoceramics, piezophase, piezomaterial, ceramic technology, microstructure

  • Optimization of a bending-type piezoelectric transducer

    This article presents the results of a parameters study on a piezoelectric flexible transducer of a beam type. The analysis was performed by the finite element method using the ANSYS Multiphysics software package. It is shown that there are optimal parameters ratios of the structural elements of the transducer under study for which it is the most effective

    Keywords: bending-type piezoelectric transducer, piezoelectric element, elastic plate, resonance frequency, conversion coefficient, Electromechanical coupling coefficient

  • Porous piezocomposite materials based on piezoceramics PKP-12.

    Piezoceramic frames made of PKP-12 material with porosity up to 50% are made. The effect of the total, open and closed porosity on the properties of porous piezoelements on a given piezoelectric material is studied. Hydrostatic tests of porous piezoelements have been performed to determine the pressure at which irreversible changes occur.

    Keywords: piezoceramics, PKP-12, piezocomposites, porous piezoceramics, piezoelectric materials, ferroelectrics, PZT, hydroacoustics, hydrophone

  • Investigation of the influence of synthesis methods on the properties of materials used in LTCC products

    To produce controlled radio frequency and microwave devices such as phased antenna arrays, delay lines, an affordable and inexpensive way of manufacturing varactors in large quantities should be found. One of the promising ways to produce such varactors is based on the use of a BST-paste with a low firing temperature, which allows it to be integrated into a substrate of low-temperature co-fired ceramics (LTCC).

    Keywords: semiconductor, ferroelectric, BST-paste, ferroelectric condenser, LTCC technology

  • Features of the dielectric hysteresis of ferroelectrics-relaxors in a sinusoidally changing electric field

    The loops of the dielectric hysteresis of a soft ceramics based on PZT with Curie temperature TC=210℃ are investigated. The studies were carried out at a frequency of 50 Hz in two modes. In the first of them, the field was switched on by 0.07 seconds, in the second - it operated continuously. The amplitude of the field E_m varied from 2.5 to 25 kV / cm and switched stepwise with an interval of 15 minutes. The coercive field EC and the switchable polarization P_m were determined. The switching polarity in the saturation region turns out to be no more, in contrast to BaTiO3 and other materials, but less than the corresponding values obtained with short-term switching.

    Keywords: piezoceramics, piezoelectric material, hot pressing, dielectric hysteresis

  • Management properties of PZT piezo-ceramic material used in sonar radiating elements

    Piezoceramics phases of (1-х)PbTiO3-xPbZrO3 is the basis of most high-performance piezoelectric materials. Electrophysical and mechanical properties of these materials can be varied over a wide range by varying the composition and by processing methods: the methods and modes of sintering conditions polarization. Topical to study the influence on the properties of PZT materials processing methods at the stages of manufacturing piezoelectric samples. In the role model of the object has been selected multicomponent system PbTiO3-PbZrO3-PbNb2/3Zn1/3O3-PbW1/2Mg1/2O3-PbSb2/3Mn1/3O3. Samples of piezoelectric elements for the study were obtained in two ways: in the first case, the sintering samples was carried out by the usual ceramic technology, and in the second by hot pressing. The grain structure was formed in both cases in the presence of the glass phase, the quantity of which decreases with increasing temperature, while in the first case, an increase in the velocity of the secondary recrystallization, and in the second of its suppression. It was found that regardless of the technology of the samples εT33/ε0, d33 and VЕ1 at high temperatures, due to the increase of grain and coercive field, which complicates the process of polarization. Maximum values εT33/ε0, d33 and VЕ1 samples prepared by hot pressing at 10 - 15% higher than if received by conventional ceramic technology.

    Keywords: Piezoelectric ceramics, doping, combination, pezophase, piezomaterial

  • The development of gestosis risk assessment expert decision support system

    The expert system for practical use by doctors in hospitals is designed The systems is solve the problem of classification opinions on the gestosis development and degree during pregnancy risk. Multi-factor knowledge base derived based on the results of studies analyzed in the work, and includes a set of genomic and post-genomic signs of pregnancy complications. The main users of the system (doctors, researchers and patients) and their requirements for software implementation of the developed expert system. Structure of expert decision support system in the evaluation of the risk of preeclampsia, comprising components (characterizing developed information systems belonging to the class of expert systems), the functions and subjects were created. The types, feature space feature descriptions and attributes the knowledge base of these patients. The generalized algorithm of the system and the possibility of its further development were given.

    Keywords: Expert system, knowledge base, requirements analysis, Statistical classification, feature space, gestosis, preventive diagnostics, a personified medicine

  • Numerical modeling and analyze of discontinuous signals spectrumenterprise

    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

  • Features of the spinel phases formation in system NiO – CoO – CuO – Cr2O3

    The combination of the unique, abnormal properties shown by oxidic systems with structure of spinel on the basis of transitional elements chromites draws attention of researchers for many years. Some systems on the basis of transitional elements chromites (for example, nickel and copper chromites) have critical elements (multicritical points, lines of phase transitions of the second sort, etc.) on the phase chart. Near these elements of the phase chart materials possess unique chemical and physical properties. Therefore development methods of receiving and research of phase forming and properties in NIO-CoO-CuO-Cr2O3 system represent fundamental and practical interest for chemistry and technology of inorganic substances. In this work processes of spinel structure formation in system 0,6 NiCr2O4 – 0,2 CoCr2O4 – 0,2 CuCr2O4 from crystal chemistry positions are considered. Formation of two solid solutions on the basis of nickel (II) chromite – with structure of cubic spinel and with tetragonal distorted structure is established. The influence of cooperative Yahn-Teller effect on processes of a spinel forming and on stabilizing impact of chloride of potassium on process of education of  two spinel solid solutions is suggested. Influence of a power factor of cation stabilization in knots of a crystal lattice as one of the important factor in reaction of spinel structure formation is considered.

    Keywords: spinels, chromites of transitional elements, Jahn-Teller effect

  • Improving the efficiency of thermal power plants by controlling the combustion of fuel in the ion current signal

    The methods of improving the efficiency of thermal power plants. Improve the efficiency improvement offers reach the combustion process. Outlines the benefits of controlling the combustion of fuel in the ion current signal.

    Keywords: power system, power plants, combustion control, the ion current, the detonation

  • System of designing multifunctional reconfigurable intelligent sensors in educational process

    The article is devoted to the system of designing multifunctional reconfigurable intelligent sensors (MRIS), examines results of application of MRIS in development of educational laboratory test benches for monitoring of parameters of environment

    Keywords: intelligent sensors, system developing, MRIS, educational laboratory test benches

  • Automatic air temperature measurement system airflow

    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

  • System simulation of the service sector: scientific, educational, innovative and cultural aspects

    The paper approaches of different paradigms of simulation in the study of subsystems of modern society, including relating to the service sector - such as cultural complex, the regional scientific environment, the educational and innovation system.  Examples of models appropriate social processes and systems are presented. Concluded that modern experts studying social processes (sociologists, conflict, political scientists) should be able to use the simulation.

    Keywords: simulation, cultural complex, the scientific environment, education system, discrete-event simulation, agent-based modeling

  • Comparative analysis of porous piezoceramics modelling by effective moduli and finite element methods with experimental data

    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