207Pb and 17O NMR Study of the Electron Density Distribution in Metal Phase of BaPb_{1-x}Bi_xO_3

The 17O and 207Pb NMR spectra were measured in ceramic samples in the metallic phase of BaPb_{1-x}Bi_{x}O_3 oxides (0<x< 0.33). The inhomogeneous magnetic broadening which appears due to a distribution of the Knight shifts was analyzed in detail. It is shown that Bi atoms, which are randomly incorporated in BaPbO_3 parent compound give rise to an increased conduction electron spin density within an area which is delimited by its two first cation shells. According to NMR data the percolative overlap of these areas occurs in superconducting compositions and it is accompanied by a sharp growth of the average Knight shift . The decrease of with temperature revealed for x=0.33 evidences for an opening of the energy gap near E_F near the metal-semiconductor transition (x=0.35).Comment: submitted to Phys. Rev.

Визначення принципу законності діяльності міліції

Піскунов, Ю. В. Визначення принципу законності діяльності міліції / Ю. В. Піскунов // Вісник Харківського національного університету внутрішніх справ. - 2007. – Вип. 38. - С. 31-36Розкрито зміст принципу законності діяльності міліції та з’ясовано, що являє собою саме поняття «законність», його природу та сутність. Раскрыто содержание принципа законности деятельности милиции и выяснено, что представляет собой само понятие «законность», его природу и сущность. The content of the principle of the legality of the police’s activity is revealed and it is clarified what the concept of “legality” itself is, its nature and essence

The charge ordered state in half-doped Bi-based manganites studied by 17^{17}O and 209^{209}Bi NMR

We present a $^{209}$Bi and $^{17}$O NMR study of the Mn electron spin correlations developed in the charge ordered state of Bi$_{0.5}$Sr$_{0.5}$MnO$_{3}$ and Bi$_{0.5}$Ca$_{0.5}$MnO$_{3}$. The unusually large local magnetic field $^{209}H_{loc}$ indicates the dominant $6s^{2}$ character of the lone electron pair of Bi$^{3+}$-ions in both compounds. The mechanism connecting the $s$ character of the lone pairs to the high temperature of charge ordering $T_{CO}$ is still not clarified. The observed difference in $^{209}H_{loc}$ for Bi$_{0.5}$Sr$_{0.5}$MnO$_{3}$ to Bi$_{0.5}$Ca$_{0.5}$MnO$_{3}$ is probably due to a decrease in the canting of the staggered magnetic moments of Mn$^{3+}$-ions from. The modification of the $^{17}$O spectra below $T_{CO}$ demonstrates that the line due to the apical oxygens is a unique local tool to study the development of the Mn spin correlations. In the AF state the analysis of the $^{17}$O spectrum of Pr$_{0.5}$Ca$_{0.5}$MnO$_{3}$ and Bi$_{0.5}$Sr$_{0.5}$MnO$_{3}$ prompts us to try two different theoretical descriptions of the charge-ordered state, a site-centered model for the first manganite and a bond-centered model for the second one.Comment: 10 pages, 7 figure

First principles calculations of the atomic and electronic structure of F centers in bulk and on the (001) surface of SrTiO3

The atomic and electronic structure, formation energy, and the energy barriers for migration have been calculated for the neutral O vacancy point defect F center in cubic SrTiO3 employing various implementations of density functional theory DFT. Both bulk and TiO2-terminated 001 surface F centers have been considered. Supercells of different shapes containing up to 320 atoms have been employed. The limit of an isolated single oxygen vacancy in the bulk corresponds to a 270-atom supercell, in contrast to commonly used supercells containing 40–80 atoms. Calculations carried out with the hybrid B3PW functional show that the F center level approaches the conduction band bottom to within 0.5 eV, as the supercell size increases up to 320 atoms. The analysis of the electronic density maps indicates, however, that this remains a small-radius center with the two electrons left by the missing O ion being redistributed mainly between the vacancy and the 3d z2 atomic orbitals of the two nearest Ti ions. As for the dynamical properties, the calculated migration energy barrier in the low oxygen depletion regime is predicted to be 0.4 eV. In contrast, the surface F center exhibits a more delocalized character, which leads to significantly reduced ionization and migration energies. Results obtained are compared with available experimental data

Artificial Intelligence in Engineering Education

Due to the growing interest in artificial intelligence in recent years, teaching this discipline to students of applied technical specialties is becoming relevant. Despite the formation of this scientific direction for almost 70 years, there is still no clear understanding of the terminology of this science, its tasks at the present stage and its application in engineering education. Moreover, the artificial intelligence terminology often misleads students. The article examines the current situation with the development of ideas related artificial intelligence, the possibility of its using in engineering education. Based on the analysis of the real possibilities of artificial intelligence, the actual content of education in the discipline of “Artificial intelligence in transport construction” is determined. The article focuses on users of artificial intelligence, not developers. The authors consider the competencies of a specialist that can be formed during the study of the above indicated discipline, as well as new relevant competencies that are necessary for a specialist in connection with the wide dissemination of artificial intelligence in the conditions of his/her professional activity. The functional model of artificial intelligence used in teaching students how to interact with it is considered. The article gives the examples of tasks solved by students today with the help of artificial intelligence technology during trial training