Phase equilibria and thermodynamic properties of oxide systems on the basis of rare earth, alkaline earth and 3d-transition (Mn, Fe, Co) metals. A short overview of

Review is dedicated studies of phase equilibria in the systems based on rare earth elements and 3d transition metals. It’s highlighted several structural families of these compounds and is shown that many were found interesting properties for practical application, such as high conductivity up to the superconducting state, magnetic properties, catalytic activity of the processes of afterburning of exhaust gases, the high mobility in the oxygen sublattice and more

Structure modification of the PI-regulator, providing the best quality of the process

Статья посвящена проблематике построения классических ПИ-регуляторов и нахождению решения улучшения качества процесса путем модификации его структуры. В статье производится сравнение двух вариантов модификации структурных схем ПИ-регулятора на примере линейного объекта первого порядка. Приведено доказательство непосредственного влияние расположения пропорциональной составляющей на качество процессов, происходящих в системе. Приводится небольшой расчет, показывающий эффект дифференцирования, возникающий при использовании схемы классического ПИ-регулятора. Приводятся графики сравнивающие качество процесса в обеих модификациях ПИ-регуляторов. Графики получены в результате моделирование в пакете программ Matlab. По результатам расчетов и моделирования системы в пакете программ Matlab делается вывод, что качество процесса в классическом ПИ-регуляторе значительно хуже, нежели в его измененной схеме.The article is about the construction of the classical PI-regulators and finding solutions to improve the quality of the process by modifying its structure. The article compares two versions of the structural modification schemes PI-controller as an example of a linear object of the first order. Give a proof of direct influence of the location component proportional to the quality of the processes occurring in the system. Given a small settlement, showing the effect of differentiation that occurs when using the scheme of classical PI-regulator. Provides graphs comparing the quality of the process in both versions PI-regulators. Graphics obtained through modeling software package Matlab. According to the results of calculations and simulation systems in the software package Matlab concludes that the quality of the process in a classic PI-regulator is significantly worse than in its schema changes

Phase equilibria, crystal structure and oxygen content of intermediate phases in the Y-Ba-Co-O system

The phase equilibria in the Y-Ba-Co-O system were systematically studied at 1373 K in air. The intermediate phases formed in the Y-Ba-Co-O system at 1373 K in air were: YBaCo2O5+δ, YBaCo4O 7 and BaCo1-yYyO3-δ (0.09≤y≤0.42). It was shown that YBaCo2O5+δ possesses tetragonal structure with the 3ap×3a p×2ap superstructure (sp. gr. P4/mmm). High-temperature X-ray diffraction analysis of the YBaCo2O 5+δ in the temperature range from 298 K up to 1073 K under Po2=0.21 atm has not shown any phase transformations. The value of oxygen content for the YBaCo2O5+δ at room temperature was estimated as 5.40 and at 1323 K it was equal to 5.04. Thermal expansion of sample shows a linear characteristics and the average thermal expansion coefficient (TEC) is about 13.8×10-6, K-1 in the temperature range 298-1273 K. The homogeneity range and crystal structure of the BaCo1-yYyO3-δ (0.09≤y≤0.42) solid solutions were determined by X-ray diffraction of quenched samples. All BaCo1-yYyO3-δ solid solutions were found to have cubic structure (sp. gr. Pm3m). The unit cell parameters were refined using Rietveld full-profile analysis. Oxygen nonstoichiometry of BaCo 1-yYyO3-δ solid solutions with 0.1≤y≤0.4 was measured by means of thermogravimetric technique within the temperature range 298-1373 K in air. Thermal expansion of BaCo 1-yYyO3-δ (y=0.0; 0.1; 0.2; 0.3) samples was studied within the temperature range 298-1200 K in air. The projection of isothermal-isobaric phase diagram for the Y-Ba-Co-O system to the compositional triangle of metallic components was presented. © 2013 Elsevier Inc

STRUCTURE AND PHYSICOCHEMICAL PROPERTIES OF COMPLEX OXIDES Y1.2Ba1.8Fe3-XCoXO8+ Δ (X = 1.02, 1.05 AND 1.08)

The purpose of the study is to determine the structure, oxygen nonstoichiometry and phys-icochemical properties of complex oxides with the general formula Y1.2Ba1.8Fe3 - xCoxO8 + δ, where x = 1.02, 1.05, and 1.08.Работа выполнена при поддержке совета по грантам Президента Российской Фе-дерации стипендии Президента Российской Федерации молодым ученым и аспирантам (Конкурс СП-2019) № СП-3689.2019.1«Получение новых перспективных матери-алов для электрохимических устройств на основе феррита иттрия-бария»

STRUCTURE OF OXIDE MATERIALS Y2Ba3Fe5-XCoXO13-Δ

Y2Ba3Fe5-xCoxO13-δ phases have been prepared using a glycerol-nitrate technique at 1373 K in air. The X-ray diffraction (XRD) pattern for the single phases were refined by the Rietveld method within the tetragonal structure (space group P4/mmm).Работа выполнена при поддержке совета по грантам Президента Российской Фе-дерации стипендии Президента Российской Федерации молодым ученым и аспирантам (Конкурс СП-2019) № СП-3689.2019.1«Получение новых перспективных материалов для электрохимических устройств на основе феррита иттрия-бария»

Magnetic properties of Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) double perovskite structure

Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) double perovskites were synthesized by pyrolysis of glycerol-salt mixtures and their magnetic properties were investigated. X-ray diffraction was employed to refine crystal structures of these perovskite materials and set sample purity degree. The magnetic ground state of Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) has been characterized using magnetic susceptibility measurements. They indicate that Sr2Ni0.75Mg0.25MoO6 is ordered in an antiferromagnetic state below 56 K while Sr2Ni0.5Mg0.5MoO6 is paramagnetic. © Published under licence by IOP Publishing Ltd.3.6121.2017/8.9A03.21.0006, 02.The work was supported by MES of RF (contract No. 3.6121.2017/8.9), and by Act 211 Government of RF (contract No. 02.A03.21.0006), and supported in part y FASO of Russia (theme “Flux” No. AAA-A18-118020190112-8)

PHASE EQUILIBRIUM IN THE 1/2Dy2O3-SrO-CoO SYSTEM

The purpose of this study is to investigate the phase equilibria in the 1/2Dy2O3-SrO-CoO system at 1100°C in air. At present two binary oxides SrCoO3-δ, Sr3Co2O7-δ and individual oxide Dy0.14Sr0.86CoO3-δ were obtained

PHASE EQUILIBRIA, CRYSTAL STRUCTURE, OXYGEN NONSTOICHIOMETRY AND THERMAL EXPANSION OF COMPLEX OXIDES FORMED IN THE Nd–Sr–Fe–O SYSTEM

The phase equilibria in the Nd-Sr-Fe-O system were systematically studied at 1373 K in air. The homogeneity ranges and crystal structure of the solid solutions were determined by X-ray diffraction analysis. The changes of oxygen content in the solid solutions versus temperature in air were determined by thermogravimetric analysis. The average thermal expansion coefficients for the Nd1-xSrxFeO3- (0.6x0.8) samples were calculated within the temperature range 298-1373 K in air

Phase Behavior of Aqueous Na-K-Mg-Ca-CI-NO3 Mixtures: Isopiestic Measurements and Thermodynamic Modeling

A comprehensive model has been established for calculating thermodynamic properties of multicomponent aqueous systems containing the Na{sup +}, K{sup +}, Mg{sup 2+}, Ca{sup 2+}, Cl{sup -}, and NO{sub 3}{sup -} ions. The thermodynamic framework is based on a previously developed model for mixed-solvent electrolyte solutions. The framework has been designed to reproduce the properties of salt solutions at temperatures ranging from the freezing point to 300 C and concentrations ranging from infinite dilution to the fused salt limit. The model has been parameterized using a combination of an extensive literature database and new isopiestic measurements for thirteen salt mixtures at 140 C. The measurements have been performed using Oak Ridge National Laboratory's (ORNL) previously designed gravimetric isopiestic apparatus, which makes it possible to detect solid phase precipitation. Water activities are reported for mixtures with a fixed ratio of salts as a function of the total apparent salt mole fraction. The isopiestic measurements reported here simultaneously reflect two fundamental properties of the system, i.e., the activity of water as a function of solution concentration and the occurrence of solid-liquid transitions. The thermodynamic model accurately reproduces the new isopiestic data as well as literature data for binary, ternary and higher-order subsystems. Because of its high accuracy in calculating vapor-liquid and solid-liquid equilibria, the model is suitable for studying deliquescence behavior of multicomponent salt systems