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The rheological characteristics of systems based on stabilized zirconium dioxide containing previously unused dispersing additives from BYK-Chemie, GmbH, have been studied to obtain photo-cured suspensions with properties that allow 3D-printing of ceramic samples of complex shape by stereolithography. The suitability of the compositions has been demonstrated on prototypes of thin-walled ceramic crucibles for thermal analysis. Ill. 4. Ref. 21. Tab. 2.

The effect of copper acetate addition to an aqueous solution of aluminum nitrate and glycine on the solution-combustion synthesis (SCS) of 4CuO/Al2O3 nanocomposites was investigated by XRD, SEM, and DTA methods. The presence of copper acetate in starting solution favored the complete conversion of NO2 to N2 at off-stoichiometric glycine contents (φ < 1). The replacement of copper nitrate with copper acetate was found to give a 2-fold decrease in combustion temperature, which markedly raised the yield of target fine powder. Synthesized composites represented a mixture of amorphous γ-Al2O3 and crystalline CuO, Cu2O, and Cu. Upon annealing at 800–850°C, the formation of CuAl2O4 spinel was observed.

Manganese oxides were synthesized via combustion reactions with glycine and citric acid. When the synthesis used reaction solutions containing predominant amounts of citric acid Σ(φcit + φgl) = 1.8–2.1 at φgl = 0.5, the reactions proceeded with moderate intensity at a maximum temperature not higher than 315°C. The resulting nanopowders (16–33 nm) were dominated by tetragonal Mn3O4. The primary crystallites were assembled into laced “crumpled paper” aggregates with numerous holes and through pores and had specific surface area of 22–27 m2/g. The variations of the maximum combustion temperature as a function of the reactor area, the mass of the obtained oxide, and the water content in the xerogel were calculated.

Three types of solid solutions of new nickel–cobalt–manganese spinels were synthesized by substitution for manganese cations in oxide Mn3O4: Ni(1 – x)Mn(2 + x)O4, Ni(1 – x)Co(1 – x)Mn(1 + 2x)O4, and Ni(1 – 2x)Co(0.5 – x)Mn(1.5 + 3x)О4. Complex oxides have been produced by solution combustion synthesis. The produced spinels expand the range of materials suitable for using as anodes of lithium-ion batteries.

Solution combustion synthesis (SCS) of zinc oxide was performed using a binary fuel, glycine and citric acid. It was established that combustion occurs due to oxidation of zinc nitrate–glycine complexes. Citric acid acts as an inhibitor of SCS reaction. An increase in relative content of organic fuel in the solution leads to a reduction in maximal combustion temperature and to formation of elemental carbon (0.2–1.6 wt %) and organic fragments (1.55–3.29 wt %) in SCS-produced zinc oxide. Carbon impurity and organic fragments were removed by annealing at 600°С. The produced wurtzite-type ZnO crystals had a size of 27–37 nm and were assembled into agglomerates. After annealing at 500°С, the specific surface of the powder was 8.44–11.09 m2/g. The photocatalytic activity of ZnO powder was evaluated from the rate of hydroquinone photodecomposition in solution.

The article reveals one of the acute aspects of higher education – the use of modern digital technologies. The article describes the possibilities of modern service programs used in the learning process, methods of presentation of educational material and knowledge control. The interpenetration of the content of different academic disciplines as a factor of creating a unified educational space through modern digital technologies is analyzed in the article. The use of modern digital technologies is considered as a factor of successful mastering of educational material. The authors come to the conclusion that the productive use of digital technologies, the involving students in an independent search, the selection of information forms students' competencies that meet modern requirements. Using test system developed at MPEI for grammar assignments is presented in the article.

The crystal structures of Ca1.5Mn0.5V2O7 (I) and Ca1.5Cd0.5V2O7 (II) synthesized by the citrate method and by a conventional solid-state reaction, respectively, were determined using X-ray powder diffraction data. It was found that the compound I has a monoclinic crystal structure a = 4.88563(9) Å, b = 11.21279(22) Å, c = 5.69643(11 Å), β = 96.376(7)°, V = 310.132(10) Å3 (space group P21/c), Z = 2). Compound I has a narrow homogeneity region Ca1.5±0.1Mn0.5±0.1V2O7. The vanadate Ca1.5Cd0.5V2O7 crystallizes in the triclinic system with the parameters a = 6.66139(6) Å, b = 6.93019(7) Å, c = 7.02211(6) Å, α = 85.4404(9)°, β = 63.7505(7)°, γ = 82.5515(10)° и V = 288.201(5) Å3 (space group P$\bar 1$, Z = 2). It is one of the formulations of the primary solid solution, formed as a result of the substitution of part of the calcium cations for cadmium cations in Ca2V2O7.

A cathode material for lithium-ion batteries–LiNi1/3Co1/3Mn1/3O2–was prepared by solution combustion synthesis and characterized by XRD, SEM, and galvanostatic charge/discharge cycling. The sample calcined at 950°C for 10 h showed best charge/discharge performance. An initial discharge capacity (C) of 150.5 mA h g–1 retained 95.7% of its value after 75 charge/discharge cycles at Ic = 14 mA g–1 (0.2C rate), Id = 70 mA g–1 (0.5C rate).

New vanadatogermanates Ca3–xMe2 + xV2GeO12, Ca3Mе2VGe2O12, and Ca3Me2Ge3O12, where Me = Mg, Mn, Co, Ni, Fe, Zn, and x = 0–1, have been synthesized through coupled substitutions of cations in the initial garnets Ca2.5Mn2V3O12 or Ca3Fe2Ge3O12. The unit cell parameters of the synthesized samples have been determined. Probability analysis of the cation distribution in the octahedral positions of the crystal lattice as a function of crystallographic radii has been performed taking into account the spin state of the cations.

Structural magnetic elements observed in sunspot penumbrae are employed as indicators of motions occurring in and around penumbrae. The analysis presented here is base on SDO/HMI continuum images and magnetograms of the line-of-sight field obtained for the active region NOAA 11117. In a first approximation, the penumbral magnetic fields can be considered alternating spines and interspine filaments. In the plane of the sky, spines are thin radial elements with higher field strengths and lower magnetic-field inclinations compared with those in surrounding areas. It is confirmed that spines first appear as protrusions of the umbra magnetic fields visible in magnetograms, and then develop simultaneously with the growth of the penumbra. The departure of magnetic elements from penumbrae as a result of the detachment of the ends of spines begin 1–1.5 h after the spine formation. Inmature penumbrae, magnetic elements emerge fairly often, and the departure of groups of field elements sometimes generates structures resembling moving ribbons. The velocities of magnetic elements that have separated from spines are a factor of two to three lower than those of elements that have separated from inter-spine filaments. The results obtained agree well with an “uncombed” model for the penumbral magnetic fields.

International audience; This work presents an original approach to obtaining highly sensitive ultrathin film sensors that allows molecular design of surface-active modular molecules by completing a signal anthraquinone block with hydrophobic radicals and polar receptor groups, with their number and size provided in accordance with the sensor type. An important advantage of the suggested approach is that it not only allows the functioning of sensors in the aqueous medium, but also their manufacturing (supramolecular assembly). The key regularity of ligands of the suggested series is selectivity with respect to mercury and copper cations. Application of amphipilic ligands in film liquid (Langmuir monolayers) and solid-state (Langmuir-Blodgett films) sensors allowed developing optical sensors for mercury and copper cations with the detection limit, as dependent on the sensor type, varying from several to hundredths of ppm.

The formation of the penumbra of the leading spot of the active region NOAA 11117 has been studied using data fromthe Solar DynamicObservatory (SDO). HMI data on longitudinal magnetic fields, line-of-sight velocities, and continuum images were used. The appearance of localized upflows between the umbra and undisturbed photosphere precedes the penumbra formation. The sizes of them reach 1.5″–2″ and the velocity increases to 1 km/s over several minutes. These localized upflows change themselves to a region of material flowing horizontally from the penumbra (the Evershed effect). The formation of individual spine namely fine radial element of the penumbra magnetic field with higher strength and lower inclination than in the surrounding is traced for the first time. The formation of the spine manifests itself as appearance of region of 2″–3″ in size with enhanced upflow near the sunspot umbra, protrusion in longitudinal-field contours on one side of the upwelling center, and the subsequent appearance of magnetic pole of opposite polarity on the other side of the upwelling. This process is accompanied by a bending of the contour marking the boundary of the undisturbed photosphere, which puts the upwelling center in a zone of higher brightness. One possible explanation for this is the emergence of hot magnetic tube. The appearance and growth of the sunspot spines results in the formation of the penumbra.

The composition of powders produced in reactions of Solution Combustion Synthesis (SCS) of zinc nitrate with glycine and a mixture of glycine and citric acid has been studied. The precursors formed on completion of solution combustion reactions were established to contain ZnO and up to 7 wt% of carbonaceous fragments due to incomplete oxidation of fuel. The latter are mixtures of residual carbon (0.2−3 wt%) and the fragments of citric acid decomposition, bound carbon, (0.6–4.4 wt%), which are strongly disordered carbon structures in nature, including amorphous ones. The performed thermal analysis of precursors and modeling allow us to suppose that the process of additional oxidation takes place in two stages – at 240−280 °C (oxidation of organic fragments) and 410−424 °C (oxidation of residual carbon) and is incomplete in character. It was shown that the complete removal of the carbonaceous fragments of organic fuel needs the temperatures close or over 900 °C. The best conductivity of ZnO were 1.13·10−7 and 9.19·10−8 S/cm after SCS and annealing 650 °C, respectively.

The study of the phase composition of the SrCo2(VO4)2 – SrCo2(PO4)2 system showed that it belongs to pseudo binary equilibria. The new phosphate-vanadates Sr2.4-xCo2.6+xP3VO15, x ​= ​0–0.04, was found to crystallize in the Sr2.36Mg2.64P4O15 structural type. The crystal structure of the Sr2.4-хCo2.6+xP3VO15 (x ​= ​0.00, 0.02 and 0.04) consists of three types of tetrahedra, Co(1)O4, P/V(1)O4 and P(2)O4, one octahedron, Sr/Co(2)O6, and ten-fold oxygen coordination around Sr(1) ions. There are two types of chains directed along c-axis, consisting of edge-sharing octahedra, Sr/Co(2)O6, and corner-sharing tetrahedra, Co(1)O4, respectively. These chains are connected through P/V(1)O4, that form P/V(1)2O7 pyro-groups, and single P(2)O4 groups. Magnetic susceptibility of Sr2.4-хCo2.6+xP3VO15 (x ​= ​0.00, 0.02, 0.04) measured in the temperature range from 2 to 300 ​K is found to be determined by linear chains of tetrahedrally surrounded cobalt and by paramagnetic octahedral cobalt ions.

Submicron CaZrO3 powder is obtained in combustion reactions (solution combustion synthesis—SCS) with glycine. It is found that SCS reduces the sintering temperature of CaZrO3 powders. The dielectric properties of calcium zirconate ceramics are studied by the electrochemical impedance method. It is shown that a ceramics of powders obtained by the SCS method has high dielectric characteristics.

The conditions for obtaining oxide compounds in combustion reactions of nitrates of metals with organic chelating–reducing agents such as amino acids, urea, and polyvinyl alcohol are reviewed. Changing the nature of internal fuels and the reducing agent-to-oxidizing agent ratio makes possible to modify the thermal regime of the process, fractal dimensionality, morphology, and dispersion of synthesized functional materials. This method can be used to synthesize simple and complex oxides, composites, and metal powders, as well as ceramics and coatings. The possibilities of synthesis in combustion reactions are illustrated by examples of αand γ-Al2O3, YSZ composites, uranium oxides, nickel powder, NiO and NiO: YSZ composite, TiO2, and manganites, cobaltites, and aluminates of rare earth elements.

The rare phenomenon of the coalescence of two rotating sunspots of the same magnetic polarity during the emergence of the active region NOAA 11117 is investigated using data from the SDO space observatory. The coalescing spots rotated in opposite directions. The leading spot which formed from this process rotated counterclockwise with an angular velocity of 4°/h. A possible explanation is presented, based on a model of the emerging, twisted magnetic Ω flux tube that interacts with convective flows as it crosses the convective zone.

The emergence of new magnetic flux in the powerful active region NOAA 10488 on the Sun and the formation of a leading spot is studied using SOHO/MDI data. Magnetograms of the longitudinal magnetic field and radial-velocity data obtained with a temporal resolution of 1 min are analyzed. The analysis begins several hours before the appearance of the top of a rising buoyant loop-like tube of magnetic field in the photosphere and finishes two days later, when the leading spot has formed. The emerging arches of magnetic field had a complex, multi-layered structure. Their apparent concentration can be explained by the emergence of the leading base of an ascending Ω tube. The new magnetic flux emerged in the inner parts of the active region throughout the formation of the leading sunspot, and was accompanied by the development of a penumbra and the appearance of the Evershed effect in the southwest sector of the sunspot. Simultaneous with the development of Evershed flows, the outer parts of the longitudinal magnetic field were gradually separated from the sunspot in the radial direction. As a result, a moat and a quasi-annular structure were formed in the magnetic field. The formation of a “moat” cell is part of the unified large-scale formation of the sunspot and the entire active region. The formation of an active region and of its structures is a manifestation of large-scale processes taking place in subphotospheric layers.

The average interatomic distances D in oxygen polyhedra MOn of isostructural oxides were proposed to be estimated using the equation D = Kɛ(RM + RO) or D = Ax2 + Bx + C, where x = ɛ(RM + RO), ɛ is the ionicity of the M-O bond, RM is the ionic radius of the cation M with account for the coordination in the polyhedron, and RO is the ionic radius of oxygen. Calculations were made for MO oxides having the rock-salt structure; Ln2O3 oxides, where Ln = Ce-Yb; and the MO2 oxides having the rutile and fluorite structures.

The emergence of photospheric magnetic fields and the dynamics of the associated pattern of vertical motions in a developing active region are studied based on SOHO/MDI data. Objects were selected for which complete time series of data were available, so as to make it possible to determine the onset time of the magnetic-field emergence at the surface and tracing the formation of the first pores. The active regions studied originated near the central meridian. The total area of sunspots in these regions exceeded 100 millionths of the hemisphere at the maximum of active region evolution. A generalized evolutionary scenario is constructed for the magnetic field and vertical motions in the emerging active region. An asymmetry in the Doppler velocities is noted at an early stage of the active-region development, which corresponds to a matter flow from the leading to the trailing end of the emerging Ω-shaped tube. A direct relationship is found between the matter-downflow velocity in the area of the pore development and the growth in the strength of the longitudinal magnetic field.

The dynamics of the magnetic field and velocity field during the birth and an early development stage of a major active region is studied. SOHO MDI longitudinal-component magnetograms, Dopplergrams, and continuum images are used. The presence of an enhanced material upflow in the photosphere during the passing of the top of the magnetic flux loop, forming the active region, is revealed. The maximum upflow velosity is 2 km/s and the maximum size of the upflow area exceeds 20000 km. The lifetime of the upflow is about two hours. The undulating form of the magnetic flux tubes crossing the photosphere is confirmed. A structural-analysis technique is used to show that the trailing polarity field at the formation stage of the active region is more highly structured than the leading polarity field.

The evolution of photospheric velocities from the first minutes after the emergence of fresh magnetic flux and the formation of the first pores in active region NOAA 10488 is studied with a time resolution of 1 min and spatial resolution of 4″. The emerging magnetic flux of a major active region is initially a bundle of magnetic-flux loops. Some of these loops erupt through the system of supergranular cells with speeds of up to 1 km/s within 15–25 min and form pores and small spots. It is suggested that the development of a pore represents the emergence of a horizontal magnetic field, which is converted into elements with a strong vertical magnetic field. The region of ascending plasma initially coincides with the zero line of a bipolar magnetic pair. Downflow and upflow regions are related to and appear with the development of pores. During the first hours of their evolution, the trailing-polarity pores exhibit downflows with mean speeds of ∼500 m/s, while upflows with speeds of ∼250 m/s dominate near the leading-polarity pores. It is concluded that a matter flow from the leading to the trailing end is present in the rising loop of a magnetic flux tube, in agreement with well-known numerical-simulation results. The flow that develops in the magnetic-flux tube erupting through the convection zone persists when pores and small spots emerge in the photosphere, at least during the first hours of their evolution.

Analysis of SOHO longitudinal magnetograms and Dopplergrams has revealed the appearance of a region of enhanced upflow of matter in the photosphere when the top of a loop-shaped magnetic flux tube forming a large active region passed through it. The maximum upflow velocity reached 2 km s−1, the maximum size exceeded 20 000 km, and the lifetime was about 2 h.

New solid solutions, Bi2−x−yTmxNbyO3+δ, with tetragonal and cubic structures have been synthesized in the Bi2O3-Tm2O3-Nb2O5 system, and their electrical conductivity has been measured at temperatures from 670 to 1020 K. The 1020-K conductivity of the tetragonal solid solution Bi1.8Tm0.15Nb0.05O3+δ is comparable to that of Bi1.75Tm0.25O3, the best conductor in the Bi2O3-Tm2O3 system.

The complex active region NOAA 9672 is studied when it was near the central meridian, from October 21–26, 2001. At that time, there was an emergence of new magnetic flux, with the ongoing formation of a filament. The dynamics of the magnetic field are studied in order to search for their possible manifestations in the filament structure, using SOHO MDI magnetograms, SOHO EIT and TRACE filtergrams in the 171 A line, and Hα filtergrams available via the Internet. Our earlier conclusion that filaments form at the boundaries of supergranules near polarity-inversion lines is confirmed. The conclusion of Chae that sinistral filaments have positive magnetic helicity is also confirmed. New information about magnetic-field decay processes is obtained. The direction of motion of the magnetic poles and their relative positions suggest that the axial field of a filament forms as a result of either reconnection of cancelling magnetic poles, or emergence of horizontal magnetic-flux tubes.

The formation of filaments in solar bipolar active regions is investigated, giving particular attention to the relationship between this process and the pattern of supergranular convection. SOHO MDI and Kitt Peak magnetograms and Hα filtergrams are used. The large decaying active region NOAA 8525 is considered over the period May 4–7, 1999. The boundaries of supergranules are identified as concentrations of the line-of-sight photospheric field in magnetograms. Filaments in the central part of the active region are studied; as a whole, they are aligned with the supergranule boundaries. Variations in the magnetic field in this period were manifest primarily in the form of “cancellations” and spatial-redistribution processes consistent with the pattern of developing supergranules. These factors created the conditions necessary for the formation of a filament stretched across the entire active region; i.e., the straightening of the polarity-inversion line and reduction of the horizontal gradients of the magnetic field. One possible explanation of the results is that the magnetic-field component along the filament axis is associated with the vortical structure of horizontal flows in the supergranulation cells.

The process of active region formation was researched by analyzing the densities of electric current and electric current helicity in the photosphere. The observational data were obtained with the vector magnetograph of the Sayan observatory. The appearance (as the sunspot developed) of the part of current helicity which is determined by the vertical components of the magnetic field and electric current density was studied. It is concluded that the loop-like magnetic flux tube which is responsible for the active region emergence contains thinner tubes with the same structure. The electric current system in a sunspot is simplified as the sunspot forms perhaps because the thinner flux tubes are merged together.

An analysis is made of vector-magnetograms and of the velocity network associated with super-granulation in the photosphere, in the region of a quiescent filament. Observational data were obtained with the Sayan observatory vector-magnetograph. It is shown that (1) near the filament the magnetic field tends to be directed along the filament, and (2) supergranules line up along the filament, with the formation of a nearly continuous line of supergranule boundaries. A prominence model is suggested, accounting for many observed properties obtained in recent years. It is a dynamic model where the magnetic field is the combination of the large-scale field and flux tubes continually emerging between supergranules in the region of the polarity inversion line of the large-scale magnetic field that are aligned along that line. The coherent properties of the emerging tubes and their orientation are associated with topological pumping of the subphotospheric magnetic field by supergranulation convection. The...

The Raman scattering spectra of isostructural Bi2O3 and Bi1.8Tm0.2O3 in the course of heating have been investigated. It is shown that the sequences of structural changes with increase in temperature differ: α → δ and δ* → β → δ, respectively. In the high‐temperature region, the structure takes the form of a disordered cube irrespective of the previous history of specimens.

A differential approach to the uses of remedial gymnastics for rehabilitative treatment of patients with a variety of degenerative and dystrophic spinal lesions has been proposed. Comparative analysis of therapeutic outcomes of remedial gymnastics and modem mechanotherapy (based on the "David" training complex) is presented. Contraindications to the use of mechanotherapy based on the "David" training complex have been developed.

An accelerated method is proposed for the analysis of copper tellurides without prior separation of the elements: Copper is determined complexometrically in the presence of tellurium, when the amount of the latter is from 40 to 60%, while tellurium is determined by a bichromate method in the presence of copper, using a separate batch. The duration of the copper determination is 1.5 h and that of the tellurium determination, 4 h.