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Dispersion of spin waves in the amorphous ferromagnetic alloy Fe48Ni34P18 can be described within the model of a ferromagnet with random anisotropy: (q) = Aq2 + gμBH + δω(q), where δω(q) is an additional term linear in |q|. The method of small-angle scattering of polarized neutrons is used to prove the importance of the additional term δω(q) in dispersion. The measurements are carried out for different values of the external magnetic field H and neutron wavelength λ. The scattering map of neutrons represents a circle centered at the point q = 0. The stiffness A of spin waves is derived directly from the λ-dependence of the radius of this circle. The spin-wave stiffness A of the amorphous alloy weakly decreases from 140 to 110 meV Å2 as temperature increases from 50 to 300 K. The field dependence of the radius demonstrates the presence of an additional term δω(q) in the form of an energy gap that is almost independent of field and temperature. The value of the additional term is Δ = 0.015 ± 0.002 meV. [ABSTRACT FROM AUTHOR]

Aspects of the experimental implementation of the small-angle neutron scattering (SANS) method on a compact neutron source are considered. A scientific justification of the demand for this type of installation is formulated. A scheme for implementing the SANS method on a pulsed neutron source is proposed, which ensures the high efficiency of using a neutron beam by limiting the operating wavelength range, and, as a result, maximizing the frequency and time-averaged power/intensity of the source. The physical parameters of the key elements of the installation, such as the cold neutron moderator, the beam-chopper cascade, the collimation system, the sample unit and the wide-aperture position-sensitive detector, are described. It is shown that the small-angle scattering method can be implemented on a university-type pulsed neutron source. [ABSTRACT FROM AUTHOR]

The results of studying the possibility of measuring the energy gap of a nonfield nature in the spectrum of spin waves in ferromagnets are presented. As a research method, the technique of the small-angle scattering of polarized neutrons in inclined geometry is used, which allows one to separate the contribution of inelastic scattering. Inelastic scattering can be obtained as the difference between the intensities when the neutron beam is polarized along and against the direction of the magnetic field. Spin-wave scattering is concentrated in a cone limited by the cutoff angle θC. It is shown that the square of the cutoff angle linearly depends on the magnetic field H and the energy gap Δ of nonfield nature: . The parameter is inversely proportional to the constant spin-wave stiffness D of the material. Model calculations for the experiment on small-angle neutron scattering are presented. They convincingly show the possibility of measuring not only the spin-wave stiffness with an accuracy of several percent, but also the nonfield gap Δ with an accuracy of up to 1 μeV. The calculation technique is applied to the results of studying the classical Fe65Ni35 invar alloy at room temperature. [ABSTRACT FROM AUTHOR]

This review is devoted to describing the main synthesis methods, the properties of MgO nanoparticles, and their areas of application, such as the creation of coatings for transformer and other types of steels, coatings on glass to control the energy of transmitted solar radiation, the creation of transparent and translucent one-component ceramics, the creation of multicomponent ceramic compositions, in medicine to make antibacterial agents, etc. The main methods of obtaining MgO nanoceramics are considered: sintering at low temperatures under high pressure, high-temperature sintering, the spark plasma sintering (SPS) method, and obtaining MgO melt in plasma in a cooled crucible followed by crystallization and the formation of dense ceramics. It is shown that variations in the conditions for the synthesis of nanosized MgO powders make it possible to obtain precursors that, upon sintering, form ceramics with a density close to the theoretical one. [ABSTRACT FROM AUTHOR]

Thermodynamics of boehmite formation upon hydrothermal treatment of micron-size particles of hydrargillite and γ-Al2O3 at 200°C in various media has been studied at various treatment times. The presence of surface-bound water with low evaporation enthalpy value at the initial stages of precursor hydrothermal treatment has been revealed. It has been shown that, irrespective of precursor and hydrothermal treatment medium, the prepared boehmite has similar properties [ABSTRACT FROM AUTHOR]

We have developed a method for the preparation of boehmite (AlOOH) nanopowder with tailored properties (particle size from 10 to 40 nm, thermal conductivity below 0.02 W/(m K), specific surface area on the order of 65 m2/g, and loose bulk density in the range 0.02–0.04 g/cm3) by hydrothermal treatment of γ‑Аl2О3 nanopowder in a 1.5% HCl solution at 200°C. The steps of the process have been identified and it has been shown to be a solid-state (topochemical) transformation. [ABSTRACT FROM AUTHOR]

A method is proposed for the synthesis of nanoscale boehmite powder at low temperatures of hydrothermal treatment in 1.5 wt % HCl solution at 150 and 170°C and in water at 80, 100, and 130°C. The optimal parameters of hydrothermal treatment are found. The conversion stages of γ-Al2O3 to boehmite (AlOOH) are found; the process is solid-phase (topochemical). The physical and technological properties of boehmite nanopowder are studied. We have found that boehmite possesses similar properties despite the temperature of hydrothermal treatment. [ABSTRACT FROM AUTHOR]

Transformations of nanosized boehmite and γ-Al2O3 powders into α-Al2O3 upon heat treatment were studied by X-ray powder diffraction and transmission electron microscopy (TEM). The parameters of α-Al2O3 are reported depending on the precursor boehmite particle size. A nanosized boehmite powder while heated to 1150°С transforms consecutively into various alumina phases without changes in the shape and size of the initial particles. [ABSTRACT FROM AUTHOR]

Introduction: It is known that many psychopharmacological drugs have anti-inflammatory, as well as antibacterial and antiviral effects. Objectives: To investigate the association between the severity and duration criteria of COVID-19 with psychopharmacotherapy in double-diagnosed patients. Methods: A total of 169 case histories from a specialized infectious psychiatric department (May 2020 to January 2021) were evaluated. Progression indicators of severe and mild COVID-19, along with the duration of persistent SARS-CoV-2 viral shedding, were assessed in correlation with the administration of antidepressants, antipsychotics, and acid sphingomyelinase inhibitors (FIASMA-active drugs). Results: The use of any psychotropic agents was associated with a 0.9% increase in the risk of severe course of COVID-19 for each unit increase in the systemic inflammation index PLR, specifically in patients with intellectual disability (ICD-10 codes F70-79), when compared to patients with schizophrenia (ICD-10 codes F20-29): R²McF=0.138; AIC=181; χ²=25.8; df=9; p=0.002. High PLR values and the use of FIASMA-active drugs were associated with prolonged COVID-19 duration, while antidepressant therapy and elevated C-reactive protein levels were associated with a reduced predicted duration of viral shedding in 13.8% of variance: R²=0.0864; AIC=1299; F=5.2(3), p=0.002. Including the nosology of psychiatric disorders in the regression model increased the proportion of explained variance to 22.8%. Conclusions: Thymoanaleptic therapy for individuals with psychiatric disorders may act as a protective factor against COVID-19. There is no evidence suggesting adverse effects of antipsychotics on the severity and duration of COVID-19. Further research is necessary to investigate the effects of FIASMA-active psychopharmacological agents within nosologically homogeneous groups. Disclosure of Interest: None Declared [ABSTRACT FROM AUTHOR]

We propose a mechanism capable of describing phase transformations during the hydrothermal treatment of micron- and nanometer-sized γ-Al2O3 and Al(OH)3 powders, identify the steps of the process, and demonstrate the role of water with a small heat of vaporization in the hydrothermal treatment process. [ABSTRACT FROM AUTHOR]

We have studied the kinetics of boehmite nanopowder formation during hydrothermal treatment of γ-Al2O3 nanopowder in a 1.5% HCl solution at 200, 170, and 150°C. The results demonstrate that the temperature-dependent reaction rate constant follows the Arrhenius equation. The Ea of the process has been determined to be 84 kJ/mol. The thermodynamics of γ-Al2O3 nanopowder conversion into boehmite during hydrothermal treatment at 150°C has been studied by differential scanning calorimetry. The heat of vaporization of water from a two-phase nanosystem (γ-Al2O3 + forming boehmite) has been determined to be 8, 16, and 22 kJ/mol H2O, which points to an active role of water with a low heat of vaporization in the initial stages of the hydrothermal treatment of the γ-Al2O3 nanopowder. The heat effect of the АlООН → γ-Al2O3 conversion in the nanopowders is lower than the reference value by 7 kJ/mol AlOOH, which is attributable to the small particle size and low structural perfection of the synthesized boehmite (AlOOH). [ABSTRACT FROM AUTHOR]

The parameters of the mesostructure of amorphous zirconium dioxide and their evolution at different stages of heat treatment are determined by small-angle neutron scattering. Particles of amorphous zirconium dioxide, which form mass fractals with the dimension Dv = 2.21, are rearranged into surface fractals with a surface dimension of Ds = 2.52 upon annealing at a temperature of 400°C or higher. In the resulting system, a shell with a fractal structure is formed over a dense core (a cluster of nanoparticles of zirconium dioxide with a constant density). Transformation of the fractal system from a mass fractal into a surface one is characterized by the appearance of a core, and its growth is due to the crystallization of hydrated zirconia particles at high temperatures. A model for the formation of a fractal particle, implying the existence of a core–shell surface fractal system, is proposed. The characteristic radius of ZrO2 nanoparticles increases from 14 to 200 Å with an increase in the annealing temperature from 400 to 600°C. [ABSTRACT FROM AUTHOR]

A method for the preparation of nanosized powder metal oxides (Al2O3, MgO, and ZnO) has been developed by the sequential heat treatment of saturated solutions of salts of these metals and sucrose at a temperature of 350°C and then 800°C. The application fields and physicochemical and technological properties of the materials synthesized are determined. [ABSTRACT FROM AUTHOR]

The new compound Аl2(SO4)3 ⋅ 8(CH3)2SO, which cannot be prepared by direct synthesis, has been synthesized from an Аl2(SO4)3 ⋅ 8(CH3)2SO ⋅ 3Н2О glass. The compound has been identified by X-ray diffraction. Based on IR spectra, it has been concluded that the Al3+ ion has mixed coordination to dimethylsulfoxide (DMSO) molecules, and the ligands are linked to each other through the S and O atoms. [ABSTRACT FROM AUTHOR]

Methods for the preparation of raw materials to produce leucosapphire are considered. It is shown that the main directions in the production of high-purity aluminum oxide raw materials are: electrochemical oxidation of aluminum, decomposition of alkoxides, high-temperature treatment of aluminum oxide in a halogen-containing atmosphere, and preliminary purification of aluminum-containing compounds followed by their decomposition. It is shown that methods of the purification of aluminum hydroxide and oxide obtained by the Bayer process are the most promising for industrial use. These methods include the complex purification and simultaneous preparation of ceramic preforms starting from aluminum hydroxides or oxides by their treatment in subcritical or supercritical steam and the following heat treatment in a halogen-containing medium. [ABSTRACT FROM AUTHOR]

A new method for producing a nanosized γ-Al2O3 powder was proposed, by which a saturated solution of aluminum oxychloride and sucrose was subjected to sequential heat treatment to 350°C to form a transient species and then to 800°C to form a nanosized γ-Al2O3 powder. The optimal treatment parameters were determined. Stages of the process were identified. The transient species and the nanosized γ-Al2O3 powder were studied. [ABSTRACT FROM AUTHOR]

The processes of obtaining fine-grained corundum with a given crystal size and habit are considered. It is shown that thermocouple treatment in aqueous supercritical fluid allows one to obtain corundum from various precursors in a wide range of crystal sizes (0.01-500 μm). Powders with a crystal size in the range 20-500 μm can be obtained directly from hydrargillite prepared in the course of the Bayer Process. The size and habit of the crystals are determined by the parameters of the thermocouple treatment and properties of the process activators used. Powders with a crystal size falling in the range 30-1000 nm can be obtained by using synthesized or commercially available boehmite as a precursor for the thermocouple treatment. The crystal habit is determined by the habit of the boehmite crystals used. New methods of boehmite synthesis have been developed that allow one to obtain nonaggregated crystals with a size of 10 nm with a narrow distribution curve. [ABSTRACT FROM AUTHOR]

The process of obtaining silicon dioxide upon the interaction of fluorosilicic acid with an aqueous solution of ammonia is studied. The fluorine-containing compounds in synthesized dioxide are identified by 19F NMR spectroscopy. It is shown that the two-stage method of precipitation followed by washing, allows producing silicon dioxide with a fluorine content of units of ppm. [ABSTRACT FROM AUTHOR]

Water-acetone solutions in the AlCl3-(CH3)2CO-H2O and AlCl3-(CH3)2CO-H2O-HCl systems were obtained and studied. In both cases, the solution separated into layers to form liquid fractions of lower and higher density. The IR spectra of the fractions were studied. In the light fraction, no AlCl3 was present, but hydrogen-bonded acetone-water complexes were detected. The spectra of the heavy fraction exhibited a broad band at ~3020-3040 cm-1 corresponding to the OH groups of water from aluminum hexahydrate. As the solvent is evaporated, the band narrows down, with its position being retained. The IR spectrum of the obtained solid becomes identical to the IR spectrum of the crystal hydrate AlCl3.(H2O)6. The structures and spectral and energetic parameters of Al(H2O)63+, Al(H2O)6+123+, Al((CH3)2CO)63+, Al((CH3)2CO)43+, and (CH3)2CO.H2O were calculated by the density functional theory method (B3LYP/6-31++G(d,p)). Relying on the results, an explanation was proposed for the experimentlly observed absence of acetone molecules in the Al3+ first coordination shell. [ABSTRACT FROM AUTHOR]

A new method was proposed to produce high-flexural-strength corundum ceramics from α-Al2O3 samples synthesized by heat treatment of boehmite AlOOH at 1300°C for 5 h. It was shown that hydrothermal treatment of MDGA-grade hydrargillite at 200°C in a 0.4 wt % magnesium acetate solution for 3 days gives finely crystalline boehmite, which is a feedstock for synthesizing corundum ceramics with a flexural strength of 400 MPa. [ABSTRACT FROM AUTHOR]

A new method of synthesis of nanosized aluminum oxyhydroxide (AlOOH, boehmite) powders has been suggested through a hydrothermal treatment of nanosized γ-Al2O3 powder in water and a 1.5 wt % HCl solution at different temperatures. It has been found that hydrothermal treatment in a 1.5 wt % HCl solution leads to the purification of the starting material; different treatment durations allow one to obtain boehmite particles of different shape. It has been demonstrated that a nanosized boehmite powder is obtained upon the hydrothermal treatment of a nanosized γ-Al2O3 in water above 80°С. The nanosized boehmite powders synthesized at different temperatures have been studied by various methods. [ABSTRACT FROM AUTHOR]

A new method of synthesis of nanosized metal oxide powders (Al2O3, MgO, ZnO) has been suggested. The method involves successive heat treatment at 350°С and then at 800°С of saturated solutions of the corresponding metal salts and sucrose. Physicochemical and technological properties of the synthesized materials have been determined. [ABSTRACT FROM AUTHOR]

New promising methods for utilizing waste polyethylene terephthalate (PET) are presented. At the first stage, partial thermal destruction of PET in an enclosure resulting in the formation of a fragile material takes place. The obtained material may be ground to a fine powder for further use as a filler. In addition, the powder of partially destructed PET reacts with alkali and ammonium hydroxide solutions resulting in the formation of corresponding terephthalate solutions, from which it is possible to obtain solid terephthalates. These terephthalates may be valuable functional materials, as well as precursors for nanodispersed oxides. [ABSTRACT FROM AUTHOR]

Reactions between aqueous solutions of aluminum salts and ammonium terephthalate at pH 6-8 lead to the formation of a previously unknown, weakly ordered phase. It has signs of a layered compound with a unit cell parameter of 1.072-1.073 nm. Its empirical composition can be represented by the formula AlO · xCHO · yHO · δ(NH), where x = 0.7-1.2, y = 4.4-6.0, and δ = 0-0.4. It has good structural order across the layers, whereas the order along the layers is weaker and depends on synthesis conditions. Calcination at 120°C leads to partial dehydration and changes the order along the layers, whereas the order across the layers changes little, with a slight increase in lattice strain. Heat treatment at 400°C leads to almost complete dehydration and fully eliminates the order along the layers, whereas the order across the layers is partially retained. Firing at 800°C leads to the formation of γ-AlO. A structural model has been proposed for the new phase. [ABSTRACT FROM AUTHOR]

We have studied the behavior of terephthalic acid (TPA) particles in sodium aluminate solutions. The results demonstrate that the addition of TPA to a solution at room temperature leads to appreciable TPA particle growth and the formation of amorphous aluminum hydroxide on the surface of the crystalline TPA floccules. With increasing initial aluminum concentration in solution, the interface displaces toward the central part of the floccules and an almost complete extraction of the dissolved aluminum is reached. The aluminate ion incorporation into the structure of TPA causes its conversion to an ionized form. In the resultant structure of amorphous aluminum hydroxide in TPA, the aluminum hydroxide crystallizes over time to form bayerite. Autoclaving in water vapor at 420°C produced boehmite ranging in crystallite size from 300 to 700 nm. Heat treatment in air for 2 h at 800°C leads to the formation of γ-AlO in the form of spheres with a fiber length on the order of 300 nm and a thickness of 50-100 nm. [ABSTRACT FROM AUTHOR]

Crystalline copper terephthalate of composition Cu[C6H4(COO)2]·2H2O has been synthesized by reacting aqueous solutions of sodium terephthalate and copper sulfate, and its dehydration has been studied in the temperature range 150–300°C. The results indicate that its dehydration behavior depends on the heating rate. Slow heating (to 200°C over a period of 24 h) removes one water molecule per formula unit near 150°C and leads to the formation of an anhydrous salt and a mixture of Cu2O and CuO (a total of 12.41%) near 200°C. Heating to 300°C in 10 min leads to the formation of nearly phase-pure Cu2O. [ABSTRACT FROM AUTHOR]

A process is described for the synthesis of aluminum terephthalate by autoclaving a suspension of terephthalic acid in an aluminum chloride solution at temperatures from 150 to 390°C and pressures from 2 to 20 MPa. The conditions ensuring the maximum yield of aluminum terephthalate are established. The composition of the reaction product is determined to be Al2[C6H4(COO)2]3 ⋅ 2H2O. The effect of the liner material on the reaction between terephthalic acid and aluminum chloride solutions is analyzed. It is shown that the final product of aluminum terephthalate decomposition during heating in air to 950°C is γ-Al2O3. [ABSTRACT FROM AUTHOR]

Group I–III terephthalates were prepared: KOOCC6H4COOH, NaOOCC6H4COOH, NaOOCC6H4COONa, Mg(OOCC6H4COO) · 2H2O, Ca(OOCC6H4COO) · 3H2O, and Al2(OOCC6H4COO)3 · 8H2O. The salts were characterized by differential thermal analysis and IR spectroscopy. The results demonstrate that the thermal decomposition of the terephthalates yields metal carbonates or oxides. On heating to 1000°C, aluminum terephthalate converts into submicron-sized α-alumina particles. [ABSTRACT FROM AUTHOR]

Solid acid ammonium terephthalates were synthesized. Their structure and IR spectrum were shown to remain unchanged at nitrogen contents down to 3.48 wt %, indicating the existence of a compound of variable composition with the general formula (NH4) x H2 – x (OOCC6H4COO) ( x = 0.4–1.7). [ABSTRACT FROM AUTHOR]

Introduction: The prevalence rates of mental health issues, particularly anxiety and depression, is high among transgender people. However, the incidence of anxiety and depression in transgender people living in Russia is unclear until now. Objectives: To examine the frequency of anxiety and depression in transgender people living in Russia. Methods: The Hospital Anxiety and Depression Scale (HADS) was used for online screening for symptoms of anxiety and depression in transgender people living in Russia throughout November 2019. 588 transgender adults living in all Federal Districts of Russia (mean age 24.0±6.7) were included in the final analysis. 69.6% (n=409) of the survey participants indicated the direction of transition as transmasculine (TM), 23.1% (n=136) - as transfeminine (TW), and 7.3% (n=43) - as other (TO). Results: It was found that 45.1% (n=265) and 24.0% (n=141) of transgender people had clinically significant levels of anxiety and depression, respectively (HADS score of 11 or higher). The rates of anxiety (TM=10.21±4.68; TW=8.72±3.91; TO=10.72±4.43) and depression (TM=7.53±4.09; TW=7.40±4.19; TO=7.74±4.33) did not have statistically significant differences within the direction of transition. The anxiety and depression mean scores in all subgroups were statistically significantly higher than in the general Russian population (p<0.001; one sample t-test). Conclusions: Our findings suggest a high prevalence of depression and anxiety disorders in the transgender population as compared to the cisgender population in Russia. The identified frequency of anxiety and depression in transgender people in Russia is worrying and requires immediate action to improve the availability and quality of medical and psychological care for this group of people. [ABSTRACT FROM AUTHOR]