Thermal expansion and polarization of (1-x)PNNxPT solid solutions

The paper presents the results of detailed studies of the thermal expansion of (1-x)PbNi1/3Nb2/3O3-xPbTiO3 solid solutions with x¼0- 0.8. The anomalous and lattice contributions to deformation and the thermal expansion coefficient are analyzed and the mean square polarization Pd is determined. The results obtained are discussed within the framework of the thermodynamic theory and the Landau 2-4-6 coefficients for solid solutions are estimate

On the use of the continuous wiener filter to generalized fractional gaussian noise

The paper is devoted to the investigation of the continuous Kolmogorov–Wiener filter weight function for forecasting of the process described by the generalized fractional Gaussian noise model. Such a model may describe telecommunication traffic, see [1, 2]. Our recent papers were devoted to the corresponding weight function obtaining for the processes in the power-law structure function model [3–5], іn the “usual“ fractional Gaussian noise model [6–8] and in the Gaussian fractional sum-difference model [9]; see also a review in [10]. However, the corresponding investigation for the generalized fractional Gaussian noise model is not yet done. In [11] it is shown, in particular, that the continuous Kolmogorov–Wiener filter may be applied to prediction of smoothed heavy-tail processes. So, the problem under consideration is of interest

Development of Meta-subject Competencies of the 7-9 Grades Basic School Students through the Implementation of Interdisciplinary Mathematical Courses

As a result of the research conducted by the authors they worked out several author's interdisciplinary courses, among them a special place is taken by the course "Mathematics in Natural sciences" for the classes of the natural-science profile. It is suggested in it to consider mathematical questions when applying them to the material of related disciplines both through the study of theoretical material and in the process of solving problems, including the open type, and involving schoolchildren in the project of interdisciplinary activity. Practical use of the interdisciplinary courses allows to see the achievements of meta-subject results by schoolchildren and the successes of students both in mathematical preparation, expressed by high marks on the subject, and related disciplines, which indicates the improvement of mathematical education quality of students who received training using the proposed methodology

The effect of the probe magnetic moment orientation of magnetic resonance force microscope on the spectra of spin wave resonances

This work was supported by the Russian Science Foundation (project 16-12-10254)

Open Type Tasks in Mathematics as a Tool for Students' Meta-Subject Results Assessment

The relevance of the present study is due to the tasks of assessing the quality of secondary education, which determine students? subject knowledge along with their personal achievements, and where meta-subject skills define not only the level of educational results achieved, but also the prospects for the future high-quality training for a school graduate at any age. Thus, the purpose of the study conducted is to create approaches for making the system of tasks together with the criteria of their assessment to determine the level of students? meta-subject results. The leading methods applied are modeling systems of open type tasks, with mathematical content and systematic analysis of large samples of experimental data, based on the evaluation of the two-point scale four parameters: the optimality of students? proposed ideas, efficiency of reasoning, originality of their answer and development degree of their solutions. A pilot study conducted since 2008 has applied open tasks with ma

Investigation of the thermal expansion and heat capacity of the CaCu3Ti4O12 ceramics

The thermal expansion of the CaCu3Ti4O12 ceramics has been measured over a wide temperature range 120–1200 K. The high quality of the samples under study has been confirmed by good agreement of the results of measurements of the heat capacity in the range 2–300 K and in the vicinity of the phase transition of magnetic nature at 25 K with the data for the single crystal. No anomalies in the thermal expansion that can be associated with the phase transition at 726–732 K assumed by other investigators have been found. The influence exerted on the thermal expansion by the heat treatment of the sample in a helium atmosphere and in air has been investigated

Research Facility for Measuring Spectra of Photo-, Radio-, Thermo- and Optically Stimulated Luminescence in Luminescent Active Materials

The installation was created for the study of luminescent-active dosimetric materials. The installation can measure the spectra of photo-, radio-, thermo- and optically stimulated luminescence. The optical stimulation control unit was developed.Работа выполнена в рамках государственного задания МИНОБРНАУКИ России (тема «Диагностика», № 122021000030-1) при частичной поддержке РФФИ (проект № 20-48-660045)

Dielectric relaxation and phase transition behavior of (1–x)Pb(Zn1/3Nb2/3)O3-xBaTiO3 binary solid solutions

Dielectric relaxation and phase transition behaviors in (1–x)Pb(Zn1/3Nb2/3)O3-xBaTiO3 (PZN-BT) binary solid solutions have been systematically studied in this paper. All the compositions display a pure pseudo-cubic perovskite structure. As the BT contents increase from 10 mol% to 70 mol%, the phase transition peak becomes broader and broader, accompanying with decreases of ɛm (the maximum dielectric permittivity) and Tm (the temperature corresponds to the ɛm). Nevertheless, an abnormal increase of ɛm and Tm occurs when the BT contents exceeds 70 mol%, forming a “U” shaped curve of the compositional dependence of ɛm and Tm. Moreover, it is indicated from the new glass model fitting results that the characteristic parameter p, which represents the degree of relaxation, also shows a similar “U” shaped variation curve. Similarly, as shown in polarization-electric field loops, both remnant polarizations (Pr) and coercive fields (Ec) display the “U” shaped curve as the BT content changes from 10 mol% to 80 mol%. Finally, according to the similar variation of these key parameters mentioned above, a polarization mismatched model, which describes the destruction and reestablishment of the long range order arrangement in solid solutions composed of two kinds of ferroelectrics, is proposed to illustrate the underlying mechanism. In this PZN-BT system or other similar ABO3-type perovskite relaxors, the competition between the A-O and B-O coupling plays an important role to form the “U” shaped evolution of these key parameters. © 201