PhC-2021

Yu.A. Gubarev¹, N.Sh. Lebedeva¹, M.O. Tonkushina², I.D. Gagarin², A.Yu.. Golub², A.A. Ostroushko^2
1 G.A. Krestov Institute of Solution Chemistry of the Russian Academy of Sciences
² Institute of Natural Sciences and Mathematics of Ural Federal University named after the first President of Russia B.N. Yeltsin

Abstract: Actual problem in the field of targeted drug delivery is transport of highly toxic drugs, with undesirable side effects, in particular antitumor medicine. The thermodynamic parameters of complexation between nanocluster polyoxometalate {Mo₇₂Fe₃₀}, promising as a means of targeted drug delivery, and a cytostatic agent – doxorubicin, widely used in clinical practice, were studied. The interaction of doxorubicin with {Mo₇₂Fe₃₀} was accompanied by an exothermic effect, which indicates an energetically favorable formation of the complex. The kinetics of the release of doxorubicin from the complex in a buffer solution with a pH corresponding to the pH value of blood was studied by fluorescence spectroscopy. The rate constants of destruction processes in the complex, accompanied by the release of doxorubicin, and further complexation of the released doxorubicin with decay products were determined. In the future, it is possible to slow down the release of doxorubicin by stabilizing the {Mo₇₂Fe₃₀}, for example, when it is associated with albumin.
Keywords: Nanocluster polyoxometalates, doxorubicin, complexation, targeted delivery, nanoparticles, rate constant, thermodynamic parameters

O.A. Golovanova
Omsk State University named after F.M. Dostoevsky

Abstract: Sr -substituted tricalcium phosphate was obtained by precipitation from aqueous solutions. Synthetic solid phases were investigated using X-ray phase analysis, IR spectroscopy, scanning electron microscopy, energy dispersive analysis. The supernatant was examined for the presence of Ca²⁺ and PO₄^3- ions to calculate the    Ca/ P ratio. It was revealed that strontium ions are part of tricalcium phosphate, but do not change its phase composition. The addition of strontium ions to the initial solution contributes to a decrease in the size of crystallites and an increase in their porosity. When studying the bioresorbability of the obtained samples using direct potentiometry, it was found that the samples containing strontium ions in their composition have a lower value of the rate of resorption. Energy dispersive analysis data confirmed that strontium ions are included in the composition of TCP samples. But with an increase in their concentration, complete replacement of calcium ions with strontium ions in the TCP structure does not occur. At the same time, the highest values of the dissolution rate are recorded in acidic media.
Keywords: crystallization, calcium phosphates, substituted tricalcium phosphate, strontium, bioresorbability

I.E. Glazov¹, V.K. Krut’ko¹, R.A. Vlasov², O.N. Musskaya¹, L.V. Kul’bitskaya¹, A.I. Kulak^1
1 Institute of General and The Inorganic Chemistry of the National Academy of Sciences of Belarus
² Medical-Center SANTE Ltd. «Medandrovit»

Abstract: Hybrid composites based on hydroxyapatite and autofibrin were synthesized by precipitation in a medium with pH=9. Soft precipitation conditions and rapid isolation of the composite precipitates favored preservation of a biopolymer matrix of autofibrin. An effect of fibrin macromolecules contributed to destabilization of the amorphous calcium phosphate phase and formation of stoichiometric hydroxyapatite. The medium of the citrated plasma stimulated precipitation of calcium-deficient hydroxyapatite with x≈0,1 and the Ca/P ration of 1,65 which transformed into the mixture of hydroxyapatite / β -tricalcium phosphate at 800 °С. Biomimetic apatite composites were synthesized with an addition of 30 vol. % of a Simulated Body Fluid (SBF) model solution. The effect of Mg²⁺, CO₃^2-  ions of SBF promoted the stabilization of amorphous calcium phosphate and formation of carbonated hydroxyapatite that exhibited thermal stability up to 800 °С. The cummulative effect of autofibrin and ions of induced SBF provided controlling composition of the mineral part of hybrid nanocomposites without disruption of an autofibrin matrix.
Keywords: hybrid nanocomposite, hydroxyapatite, fibrin, citrated plasma, amorphous calcium phosphate, calcium-deficient hydroxyapatite, carbonated hydroxyapatite

S.A. Bibanaeva, V.M. Skachkov
The Institute of Solid State Chemistry of the Ural Branch of RAS

Abstract: The work is devoted to the study of the influence of mono – and composite metal additives on the process of processing bauxite by the hydro-alkaline method. The chemical qualitative and quantitative composition, morphology of red mud (RM) obtained under conditions of autoclave high- temperature leaching were studied. X-ray phase studies aimed at determining the composition and structure of compounds in red mud were carried out. The prospects of the method of autoclave leaching of hard-to-open bauxites with simultaneous extraction of alumina and conversion of hematite to magnetite by hydrogen gas are shown. It was found that the method allows the processing of bauxite with a high degree of alumina extraction and allows to obtain red mud with different magnetic fraction content and low sodium content. The resulting magnetized red mud is suitable for processing by magnetic separation and makes it a promising raw material for the ferrous metallurgy. The dependence of the degree of conversion of hematite to magnetite on the type of reducing agent is determined. According to the results of the research, a patent for the invention was obtained.
Keywords: the bauxite leaching, the recovery of iron, the Bayer process, red mud, hematite, magnetite

A.I. Fomin, N.A. Pan'kin
Ogarev Mordovia State University

Abstract: The surface layer of DI50-2 cast iron after its processing by electric contact welding has been investigated by methods of X-ray diffraction and electron microscopy. A 50HVA steel strip was used as a filler material. Processing technologies were used with the creation of an intermediate layer of nickel powder PC-12N-01 and without it. Results on phase composition, substructure and residual stresses are obtained. The system under study consists of α–Fe and γ–Fe phases. Substructure parameters (microstrain and block refinement) have the same values for different modes of electrical contact welding. Residual stresses are of a tensile nature and decrease when an intermediate layer of nickel powder material is created. The main mechanism of their formation is thermal effects on the material processed by electrocontact welding. Cracks may form after electrical contact welding of the tape. They are oriented mainly parallel to the surface to be treated and are due to the presence of a large temperature gradient.
Keywords: electrical contact welding, phase composition, microstrains, size of subblocks, macrostresses

D.A. Timoshenko, I.V. Sinev, V.V. Simakov, N.A. Klychkov
Saratov State University

Abstract: Tin dioxide nanowhiskers were grown by physical vapor deposition and transferred to the contact system by the frozen drop method. The sensors demonstrate gas-sensitivity. Exposing sensors to the atmosphere contained vapors of reducing-gases leads to an increasing of their conductivity. A long-term drift of the sensor conductivity during reducing-gas exposition was shown. A sensitivity response vs concentration for ethanol, acetone, and propanol- 2 vapors at temperature 300 °C was investigated. Desorption energies of the particles and the positions of the donor levels induced by adsorption of reducing gases particles were calculated by analysis of the conductivity vs concentration dependence. The calculated parameters had a significantly smaller time drift in comparison with the conductivity. Using of these parameters makes possible to recognize gas-air mixtures: classify the each of three studied samples to one of classes.
Keywords: whisker nanocrystals, tin dioxide, gas detection, semiconductor gas sensor, gas sensitivity

V.M. Skachkov
The Institute of Solid State Chemistry of the Ural Branch of RAS

Abstract: The article discusses the change in the properties of diffusion-hardening solder in dependence on the composition of the liquid metal component based on low-melting gallium alloys: gallium-tin, gallium-indium-tin and gallium-tin-zinc when interacting with the Spherical copper-tin alloy powder (SCTAP5) subjected to low-temperature (125°С) and high-temperature (500°С) heat treatment. The mechanical properties were evaluated by measuring the microhardness, and the thermal properties were studied by differential thermal analysis. Heat treatment at high temperatures promotes the transition of the solder to an equilibrium state, with a significant increase in hardness. The thermal effects of heat treatment of diffusion-hardening solders are calculated and compared. The phases formed as a result of hardening are determined by X-ray phase analysis. It is shown that different phases and nanoscale intermetallic compounds are formed at different processing temperatures. The improvement of the mechanical properties of diffusion-hardening solder in the presence of zinc dissolved in a gallium liquid alloy has been experimentally proved.
Keywords: composite diffusion-hardening solders, exothermic effects, properties, microhardness, differential thermal analysis, X-ray phase analysis

E.V. Raksha¹, V.A. Glazunova², O.N. Oskolkova¹, P.V. Sukhov¹, G.K. Volkova², A.A. Davydova¹, Yu.V. Berestneva³, M.V. Savoskin^1
1 L.M. Litvinenko Institute of Physical Organic and Coal Chemistry
² Donetsk Institute for Physics and Engineering named after A.A. Galkin
³ Complex Melioration and Protective Afforestation of the Russian Academy of Sciences

Abstract: The paper presents the investigation results of the morphology of carbon nanoparticles formed during liquid-phase exfoliation of thermally expanded graphite in tert-butanol. The thermally expanded graphite used in this work was obtained by thermal expansion of graphite nitrate with acetic and formic acids in the thermal shock mode at 500 °C and 900 °C. Initial cointercalate was shown by powder X-ray diffraction analysis to be the mixture of the IInd and the IVth stage intercalation compounds. It has been established by transmission electron microscopy that dispersions of carbon nanoparticles formed during the exfoliation of thermally expanded graphite in tert-butanol via sonication contain mainly few-layer graphenes, the planar dimensions of which reach 8 μm. The influence of the conditions for thermally expanded graphite obtaining on the morphology of resulting carbon nanoparticles is discussed. Dispersions based on thermally expanded graphite obtained at a lower temperature, in addition to few-layer graphenes, also contain a significant amount of amorphous carbon particles with planar sizes up to 100 nm.
Keywords: few-layer graphenes, liquid-phase exfoliation, graphite nitrate, cointercalation

T.I. Pravilnikova, O.A. Golovanova
Omsk State University named after F.M. Dostoevsky

Abstract: The paper presents a study of the processes of precipitation of mineral-organic formations in a model solution of blood plasma in the presence of additives of albumin, glycine, glucose, glutamic and lactic acids. The phase composition of the samples was studied by the X-ray diffraction analysis. Photos were taken to measure the surface area of the sample with modified calcium phosphate. The solid phase coating areas were highlighted in the photos and the degree of coating of steel samples was calculated using the ToupView software. The deposition of the crystal phase occurs on all the studied samples. The differences are in the distribution of crystals on the surface of the plate. The additive albumin inhibits the deposition of hydroxyapatite on the studied samples. It is shown, that additions of glucose, glutamic and lactic acids catalyze the process of hydroxylapatite deposition on the surface of a steel sample. As a percentage of the total area of the image, the largest amount of precipitated hydroxylapatite powder is observed in samples with the addition of glucose.
Keywords: mineral-organic formations, blood plasma, calcifications, crystallization, hydroxylapatite, precipitation, steel grade 12X18N10T

A.A. Ponomareva^1,2, V.E. Sitnikova¹, K.A. Tсoi^2
1 ITMO University
² Far Eastern Federal University

Abstract: The environmental parameters of power equipment are important in terms of minimizing the negative impact on the environment. Intermetallic infrared porous flameless burners are a new generation of burners with improved performance. Gas burners are among the most efficient devices for direct conversion of combustion heat into infrared energy. Despite the improved environmental characteristics of infrared porous burners compared to traditional burners, during operation they can emit unwanted and hazardous combustion products of gas mixtures (or other fuels), especially during transient and high-power modes. In this work, catalytic coatings based on cerium-based oxide systems with a small addition of silicon oxides were obtained. The deposition of the catalytic material on porous intermetallic substrates was controlled using the gravimetric method, optical analysis system, and scanning electron microscopy, and its chemical structure was investigated using IR spectroscopy. The uniform distribution of the coating over the substrate surface and the correspondence of the IR peaks with the chemical composition of the synthesized systems were detected.
Keywords: catalytic coatings, metal oxide structures, porous burners, sol-gel technology, infrared spectroscopy