ІЗОТЕРМІЧНИЙ ПЕРЕРІЗ ДІАГРАМИ СТАНУ СИСТЕМИ Al2O3−TiO2−Nd2O3 ПРИ 1400 °С

Isothermal section of the Al2O3–TiO2–Nd2O3 phase diagram at 1400 °C is constructed for the first time. It is the part of systematic investigations of Al2O3–TiO2–Ln2O3 (Ln=lanthanides,Y) systems. The 1400°C was taken as the temperature, at which no liquid is expected in the system. Samples were prepared by a chemical method. Samples were annealed in air at 1400°С for 80 hours and cooled in the furnace. Phases in the samples were determined by XRD analysis. New phases and appreciable homogeneity regions based on components and binary compounds were not found. Isothermal section consists of seven narrow twophase and eight three-phase regions. Triangulation of the system is determined by the phase Nd2Ti2O7, which is in equilibrium with compounds Al2TiO5, NdAlO3 and system components TiO2 and Al2O3. Formation of phases Nd4Ti9O24, Nd2Ti3O12 and Nd2TiO5 in binary boundary system TiO2–Nd2O3 causes the appearance of partially quasibinary sections Al2TiO5–Nd4Ti9O24, Al2TiO5–Nd2Ti3O12 and NdAlO3–Nd2TiO5. The obtained results make a significant contribution to the understanding of interactions between the components in the system studied. The system includes binary compounds with high electro-optical, ferroelectric, piezoelectric, photocatalytic properties, mikrowave dielectric ceramic. In addition, in the system we expects the existence of new three-phase and two-phase eutectics, which can be obtained in the form of high-temperature structural materials by the directional solidification. This fact opens up the possibility to fi nd and establish the coordinates of new three-phase and two-phase eutectics for directional solidifi cation and to obtain new high-temperature structural materials in the Al2O3–TiO2–Nd2O3 system

Diameter-dependent thermopower of Bi nanowires

We present a study of electronic transport in individual Bi nanowires of large diameter relative to the Fermi wavelength. Measurements of the resistance and thermopower of intrinsic and Sn-doped Bi wires with various wire diameters, ranging from 150-480 nm, have been carried out over a wide range of temperatures (4-300 K) and magnetic fields (0-14 T). We find that the thermopower of intrinsic Bi wires in this diameter range is positive (type-p) below about 150 K, displaying a peak at around 40 K. In comparison, intrinsic bulk Bi is type-n. Magneto-thermopower effects due to the decrease of surface scattering when the cyclotron diameter is less than the wire diameter are demonstrated. The measurements are interpreted in terms of a model of diffusive thermopower, where the mobility limitations posed by hole-boundary scattering are much less severe than those due to electron-hole scattering.Comment: 32 pages, 12 figures. Previous version replaced to improve readabilit

ISOTHERMAL SECTION OF THE Al2O3–TiO2–Yb2O3 PHASE DIAGRAM AT 1400 °С

One of the main directions of the modern materials development science is the development of new oxide ceramic materials for engineering, energy, chemical, aerospace, electronic and other industries in multi component systems, including containing TiO2, Al2O3 and rare earth oxides. The Al2O3‒TiO2‒Yb2O3 system attracts the attention of researchers because possibility of design of structural high-temperature materials with low coefficient of thermal expansion, as well as refractory ceramic materials. The basis of new materials creation is the study of physical and chemical interaction, which is reflected in the phase diagrams of the systems. The purpose of this study is the construction of phase diagram isothermal section for the Al2O3−TiO2−Yb2O3 system at 1400 °С, which is the part of the interaction systematic study of the Al2O3−TiO2−Ln2O3 systems, where Ln = (La, Nd, Gd, Er, Yb and Y). The samples were prepared by a chemical method. Annealed in air at 1400°С for 80 hour sand cooled in the furnace. Phase content of the samples was determined by XRD analysis. New multicomponent phases and appreciable homogeneity regions based on components and binary compounds were not found. Isothermal section consists of four narrow two-phase Al2TiO5+Yb2Ti2O7, Al2O3+Yb2Ti2O7, Yb3Al5O12+Yb2Ti2O7, Yb3Al5O12+Yb2TiO5 regions and five threephase Al2TiO5+TiO2+Yb2Ti2O7, Al2TiO5+Yb2Ti2O7+Al2O3, Al2O3+Yb2Ti2O7+Yb3Al5O12, Yb2Ti2O7+Yb3Al5O12+Yb2TiO5, Yb3Al5O12+Yb2TiO5+С-Yb2О3 fields. In addition, in the system we expects the existence of new three-phase and two-phase eutectics, which can be obtained in the form of high-temperature structural materials by the directional solidification. This fact opens up the possibility to find and establish the coordinates of new three-phase and two-phase eutectics for directional solidification and to obtain new high-temperature structural materials in the Al2O3–TiO2–Yb2O3 system

ІЗОТЕРМІЧНИЙ ПЕРЕРІЗ ДІАГРАМИ СТАНУ СИСТЕМИ Al2O3−TiO2−Yb2O3 ПРИ 1400 °С

One of the main directions of the modern materials development science is the development of new oxide ceramic materials for engineering, energy, chemical, aerospace, electronic and other industries in multi component systems, including containing TiO2, Al2O3 and rare earth oxides. The Al2O3‒TiO2‒Yb2O3 system attracts the attention of researchers because possibility of design of structural high-temperature materials with low coefficient of thermal expansion, as well as refractory ceramic materials. The basis of new materials creation is the study of physical and chemical interaction, which is reflected in the phase diagrams of the systems. The purpose of this study is the construction of phase diagram isothermal section for the Al2O3−TiO2−Yb2O3 system at 1400 °С, which is the part of the interaction systematic study of the Al2O3−TiO2−Ln2O3 systems, where Ln = (La, Nd, Gd, Er, Yb and Y). The samples were prepared by a chemical method. Annealed in air at 1400°С for 80 hour sand cooled in the furnace. Phase content of the samples was determined by XRD analysis. New multicomponent phases and appreciable homogeneity regions based on components and binary compounds were not found. Isothermal section consists of four narrow two-phase Al2TiO5+Yb2Ti2O7, Al2O3+Yb2Ti2O7, Yb3Al5O12+Yb2Ti2O7, Yb3Al5O12+Yb2TiO5 regions and five threephase Al2TiO5+TiO2+Yb2Ti2O7, Al2TiO5+Yb2Ti2O7+Al2O3, Al2O3+Yb2Ti2O7+Yb3Al5O12, Yb2Ti2O7+Yb3Al5O12+Yb2TiO5, Yb3Al5O12+Yb2TiO5+С-Yb2О3 fields. In addition, in the system we expects the existence of new three-phase and two-phase eutectics, which can be obtained in the form of high-temperature structural materials by the directional solidification. This fact opens up the possibility to find and establish the coordinates of new three-phase and two-phase eutectics for directional solidification and to obtain new high-temperature structural materials in the Al2O3–TiO2–Yb2O3 system.Вперше побудовано ізотермічний переріз діаграми стану системи Al2O3−TiO2−Yb2O3 при 1400 °С. Нових фаз і помітних областей гомогенності на основі компонентів та подвійних сполук не знайдено. У трифазних областях слід очікувати наявність п’яти потрійних евтектик Al2TiO5 + TiO2 + Yb2Ti2O7, Al2TiO5 + Yb2Ti2O7 + Al2O3, Al2O3 +Yb2Ti2O7 + Yb3Al5O12, Yb2Ti2O7 + Yb3Al5O12 + Yb2TiO5, Yb3Al5O12 + Yb2TiO5 + С-Yb2О3, а на бінарних перерізах − чотири подвійні евтектики Al2TiO5 + Yb2Ti2O7, Al2O3 + Yb2Ti2O7, Yb3Al5O12 + Yb2Ti2O7, Yb3Al5O12 + Yb2TiO5

D.V.: Project animat brain: Designing the animat control system on the basis of the functional systems theory

Abstract. The paper describes the design of an animat control system (the Animat Brain) that is based of the Petr K. Anokhin's theory of functional systems. We propose the animat control system that consists of a set of functional systems (FSs) and enables predictive and purposeful behavior. Each FS consists of two neural networks: the Actor and the Model. The Actors are intended to form chains of actions and the Models are intended to predict futures events. There are primary and secondary repertoires of behaviors: the primary repertoire is formed by evolution; the secondary repertoire is formed by means of learning. The paper describes both principles of the Animat Brain operation and the particular model of predictive behavior in cellular landmark environment.