Influence of physic-mechanical properties on a choice of metallurgical slags processing technology

Проаналізовано фізико-механічні властивості шлаків після первинної переробки – тер-мічного (термоудар) і механічного впливу на розплав, схильність відвальних шлаків до розпаду – структурним перетворенням, і можливі види механічної переробки для отримання різних видів шлакової продукції. Наводиться технологічна схема переробки відвальних шлаків (можливе застосування також і для шлаків поточного випуску) з витяганням металу і отриманням широкого спектру шлакової продукції, включаючи в'яжучі матеріали.Проанализированы физико-механические свойства шлаков после первичной переработки – термического (термоудар) и механического воздействия на расплав, склонность отвальных шлаков к распаду – структурным превращениям, и возможные виды механической переработки для получения разных видов шлаковой продукции. Приводится технологическая схема переработки отвальных шлаков (применимо и для шлаков текущего выпуска) с извлечением металла и получением широкого спектра шлаковой продукции, включая вяжущие материалы.Physical and mechanical properties of the slag after the initial processing – thermal (thermal shock) and mechanical impact on the melt, the dump slag inclination to disintegration – structural transformations and the possible kinds of mechanical processing to produce different types of slag products were analyzed. Technological scheme of dump slag (it can also be applied to the current release slags) with metal extraction and of slag products wide range, including cementations materials were given

Ferromagnetism in Co-doped ZnO films grown by molecular beam epitaxy: magnetic, electrical and microstructural studies

We studied structural, optical and magnetic properties of high-quality 5 and 15% Co-doped ZnO films grown by plasma-assisted molecular beam epitaxy (MBE) on (0001)- sapphire substrates. Magnetic force microscopy (MFM) and magnetic measurements with a SQUID magnetometer show clear ferromagnetic behavior of the films up to room temperature, while they are antiferromagnetic below approximately 200 K. Temperature dependences of the carrier mobility were determined using Raman line shape analysis of the longitudinal optical phonon-plasmon coupled modes. It has been show that the microscopic mechanism for ferromagnetic ordering is coupling mediated by free electron spins of Co atoms. These results bring insight into a subtle interplay between charge carriers and magnetism in MBE-grown Zn₁₋xCoxO films

Comparison of pressure, magnetic field and excess manganese effects on transport properties of film and bulk ceramic La–Ca manganites

The pressure, magnetic field and excess manganese effects on transport and magnetoresistance effect (MRE) have been studied in both the epitaxial films and bulk ceramics of manganites (La₀.₇Ca₀.₃)₁₋xMn₁₊xO₃₋y (x = 0–0.2). A comparison of electrical behavior in both kinds of samples of similar composition at hydrostatic pressures of up to 1.8 GPa and in a magnetic fields of up to 8 kOe has been performed. The pressure and magnetic field effects are shown to increase with increasing manganese content. Experimental data show that the pressure and magnetic field effects on temperatures of both metal–insulator transition (TMD) and MRE peak (TMR) are considerably stronger in the films than in ceramics. The hydrostatic pressure increases TMD and TMR. Magnetoresistance effect for both types of samples was shown to be favored by the pressure and magnetic field in an opposite way. A direct correlation is established between TMD and conductivity bandwidth as well as between MRE and concentration of charge carriers at applied pressure. The differences in the values of pressure effect on resistance, MRE and TMD temperature in the films and ceramics are connected with both granular structure of ceramics and the oxygen nonstoichiometry in ceramic and film samples of the same content as well as with the film strain induced by lattice mismatch between the film and the substrate. The origin of pressure–magnetic field effects is analyzed in the framework of double exchange interaction and small polaron hopping, and variable range hopping models

The relationship of anxiety level and regulatory profile of cardiac rhythm in military students in conditions of examination

The article presents the research results of a regulatory profile of cardiac rhythm in a situation of examination, depending on the level of personal and state anxiety. In order to identify the characteristics of a psychosomatic response to the situation of examination stress the level of anxiety was assessed, which made the basis for ranking groups (low-, moderate-, high - anxious cadets). Cardiac rhythm variability was investigated by the method of R. M. Baevsky, and the statistical and spectral analysis was estimated. The study involved 42 apparently healthy cadets of the first course, 35 girls and 7 boys. The average age was (17.5 ± 0.5) years. A cross-sectional (transverse) study was carried out which protocol included 2 stages: the first stage: anxiety level was determined before the exam, functioning parameters of cardiovascular system and cardiac rhythm variability were registered. The second stage: registration of above mentioned parameters immediately after the examination. The analysis of the research results showed that the level of state anxiety before the exam in all groups was above the level of trait anxiety, which was seen as a natural reaction to the situation of the examination. The reaction of the cardiovascular system and the mechanisms of the autonomic regulation of heart rhythm in a standard situation such as examination were provocative depending on the level of anxiety. Highly anxious examinees showed a higher activation of sympathetic part of autonomic division of nervous system which indicated the generalization of anxiety and possibilities of its somatization

Structure defects and properties of fianites

X-ray structure examination and spectroscopy, as well as hydrostatic method and fluorescence have been used to investigate single crystals of fianites differing in colors, doped with yttrium and rare earth ions. The crystal lattice defects, microhardness, absorption spectra and fluorescence of those fianites have been determined. It is shown that mechanical (density, hardness) and optical (color, absorption, fluorescence) properties of fianites depend on rare-earth microimpurities (Ce, Eu) and structure defects.Рентгеновскими структурным и спектральным, гидростатическим и флюоресцентным методами исследованы легированные иттрием и редкоземельными ионами фиани-товые монокристаллы, отличающиеся цветом. Определена дефектность кристаллической решетки этих фианитов, их микротвердость, спектры поглощения и флюоресценции. Показано, что механические (плотность, твердость) и оптические (цвет, поглощение, флюоресценция) свойства фианитов зависят от редкоземельных микропримесей (Ce, Eu) и дефектности структуры.Рентгенівськими структурним i спектральним, гідростатичним i флюоресцентним методами досліджено леговані ітрієм і рідкісноземельними іонами фіанітові монокристали, які відрізнялися кольором. Визначено дефектність кристалічної гратки цих фіанітів, їх мікротвердість, спектри поглинання та флюоресценції. Показано, що механічні (густина, твердість) та оптичні (колір, поглинання, флюоресценція) властивості фіанітів залежать від рідкісноземельних мікродомішок (Ce, Eu) і дефектності структури

The relationship of anxiety level and regulatory profile of cardiac rhythm in military students in conditions of examination

The article presents the research results of a regulatory profile of cardiac rhythm in a situation of examination, depending on the level of personal and state anxiety. In order to identify the characteristics of a psychosomatic response to the situation of examination stress the level of anxiety was assessed, which made the basis for ranking groups (low-, moderate-, high - anxious cadets). Cardiac rhythm variability was investigated by the method of R. M. Baevsky, and the statistical and spectral analysis was estimated. The study involved 42 apparently healthy cadets of the first course, 35 girls and 7 boys. The average age was (17.5 ± 0.5) years. A cross-sectional (transverse) study was carried out which protocol included 2 stages: the first stage: anxiety level was determined before the exam, functioning parameters of cardiovascular system and cardiac rhythm variability were registered. The second stage: registration of above mentioned parameters immediately after the examination. The analysis of the research results showed that the level of state anxiety before the exam in all groups was above the level of trait anxiety, which was seen as a natural reaction to the situation of the examination. The reaction of the cardiovascular system and the mechanisms of the autonomic regulation of heart rhythm in a standard situation such as examination were provocative depending on the level of anxiety. Highly anxious examinees showed a higher activation of sympathetic part of autonomic division of nervous system which indicated the generalization of anxiety and possibilities of its somatization

Nonclassical magnetic dynamics and negative exchange bias in Nd₀.₅Sr₀.₅MnO₃ films

The amorphous, nanoclustered, and self-organizing bilayered Nd₀.₅Sr₀.₅MnO₃ films have been prepared by a rf-magnetron sputtering. The amorphous film turn out to be a typical paramagnet with a freely moving of the individual Mn spins, the magnetic properties of which are well described by the Curie–Weiss approximation. The nanoclustered film manifests the magnetic properties mimic to the superparamagnetic particles with a nonclassical magnetic dynamics. Taking into account the unique shape of the hysteresis loops, which have hysteretic lobes at high magnetic field but are nonhysteretic as the field crosses zero, we suggest that each particle (nanocluster) is the closure magnetic domain (or magnetic vortex) rather than the single one. At the same time, the blocked to unblocked transition was observed with increasing temperature similar to the usual superparamagnet. The self-organizing bilayered film demonstrates a negative exchange bias, which is typical for the ferromagnet/antiferromagnet hybrid system in spite of that both layers in our case have a ferromagnetic origin. The magnetic properties of the films are discussed in detail on the base of modern theoretical models