Publications by authors named "Denis A Vinnik"

The syntheses and structures of dimethyl [1,2:2,3-terphenyl]-1,3-dicarboxylate (1), dimethyl 2,2-diiodo[1,2:2,3-terphenyl]-1,3-dicarboxylate (2), potassium [1,2:2,3-terphenyl]-1,3-dicarboxylate (3) and dimethyl [1,1'-biphenyl]-4,4'-dicarboxylate (4) are reported. Neighboring phenyl rings in compounds 1, 3 and 4 have a planar structure (torsion angles are 0.6-4.

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The polycrystalline SrFeO samples deeply substituted up to at.67% by Al, Ga, In, Co, and Cr cations with a high configurational mixing entropy were prepared by solid-phase synthesis. Phase purity and unit cell parameters were obtained from XRD and analyzed versus the average ionic radius of the iron sublattice.

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The results of studies on the wettability properties and preparation of porous anodic alumina (PAA) membranes with a 3.3 ± 0.2 μm thickness and a variety of pore sizes are presented in this article.

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Thrombosis-related diseases are the primary cause of death in the world. Despite recent advances in thrombosis treatment methods, their invasive nature remains a crucial factor, which leads to considerable deadly consequences. Soft magnetic robots are attracting widespread interest due to their fast response, remote actuation, and shape reprogrammability and can potentially avoid the side effects of conventional approaches.

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Multisubstituted barium ferrites with a magnetoplumbite structure were obtained by the method of solid-phase reactions with ferritization and pre-firing. Three-charged, mainly diamagnetic cations Al, Cr, Ga, and In were chosen as substituents for the Fe iron cations, the proportion of which in solid solutions did not exceed 50%. The values of the configurational mixing entropy were calculated for all the compositions.

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The development of universal methods to synthesize materials with different structures is always in the researchers' focus. Despite the fact that various structures based on magnetite have already been obtained, synthetic approaches that allow to synthesize materials with a wide range of texture and functional properties are still very poorly presented. In this work, we demonstrate that a stable magnetite hydrosol can be easily converted into monolithic structures of xero-, cryo- and aerogel by careful varying concentrations and drying conditions.

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Although copper is needed for living organisms at low concentrations, it is one of the pollutants that should be monitored along with other heavy metals. A novel and sustainable composite mineralizing sorbent based on MgO-CaO-AlO-SiO-CO with nanosized adsorption centers was synthesized using natural calcium-magnesium carbonates and clay aluminosilicates for copper sorption. An organometallic modifier was added as a temporary binder and a source of inovalent ions participating in the reactions of defect formation and activated sintering.

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Three high-entropy Sm(Eu,Gd)CrMnFeCoNiO perovskite solid solutions were synthesized using the usual ceramic technology. The XRD investigation at room temperature established a single-phase perovskite product. The Rietveld refinement with the FullProf computer program in the frame of the orthorhombic Pnma (No 62) space group was realized.

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Thrombosis-related diseases are undoubtedly the deadliest disorders. During the last decades, numerous attempts were made to reduce the overall death rate and severe complications caused by treatment delays. Significant progress has been made in the development of nanostructured thrombolytics, especially magnetically controlled.

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La-, Nd- and La/Nd-based polysubstituted high-entropy oxides (HEOs) were produced by solid-state reactions. Composition of the B-site was fixed for all samples (CrMnFeCoNi) with varying of A-site cation (La, Nd and LaNd). Nominal chemical composition of the HEOs correlates well with initial calculated stoichiometry.

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Tm-Tb co-substituted Co-Ni nanospinel ferrites (NSFs) as (CoNi) [TmTbFe]O (x = 0.00-0.05) NSFs were attained via the ultrasound irradiation technique.

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Single crystals of aluminum substituted strontium hexaferrite SrFeAlO were grown from sodium oxide based flux. The substitution level aimed for was = 1.2.

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The possibility of the formation of high entropy single-phase perovskites using solid-state sintering was investigated. The BaO-SrO-CaO-MgO-PbO-TiO, BaO-SrO-CaO-MgO-PbO-FeO and NaO-KO-CaO-LaO-CeO-TiO oxide systems were investigated. The optimal synthesis temperature is found between 1150 and 1400 °C, at which the microcrystalline single phase with perovskite structure was produced.

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Crystalline high-entropy single-phase products with a magnetoplumbite structure with grains in the μm range were obtained using solid-state sintering. The synthesis temperature was up to 1400 °C. The morphology, chemical composition, crystal structure, magnetic, and electrodynamic properties were studied and compared with pure barium hexaferrite BaFeO matrix.

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Magnetic Fe₃O₄ nanoparticles (NPs) and their surface modification with therapeutic substances are of great interest, especially drug delivery for cancer therapy, including boron-neutron capture therapy (BNCT). In this paper, we present the results of boron-rich compound (carborane borate) attachment to previously aminated by (3-aminopropyl)-trimethoxysilane (APTMS) iron oxide NPs. Fourier transform infrared spectroscopy with Attenuated total reflectance accessory (ATR-FTIR) and energy-dispersive X-ray analysis confirmed the change of the element content of NPs after modification and formation of new bonds between Fe₃O₄ NPs and the attached molecules.

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Barium hexaferrite powder samples with grains in the μm-range were obtained from solid-state sintering, and crystals with sizes up to 5 mm grown from PbO, Na₂CO₃, and BaB₂O₄ fluxes, respectively. Carbonate and borate fluxes provide the largest and structurally best crystals at significantly lower growth temperatures of 1533 K compared to flux-free synthesis (1623 K). The maximum synthesis temperature can be further reduced by the application of PbO-containing fluxes (down to 1223 K upon use of 80 at % PbO), however, Pb-substituted crystals BaPbFeO with Pb contents in the range of 0.

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The coexistence of three valence states of Mn ions, namely, +2, +3, and +4, in substituted magnetoplumbite-type BaFeMnO was observed by soft X-ray absorption spectroscopy at the Mn-L edge. We infer that the occurrence of multiple valence states of Mn situated in the pristine purely iron(III) compound BaFeO is made possible by the fact that the charge disproportionation of Mn into Mn and Mn requires less energy than that of Fe into Fe and Fe, related to the smaller effective Coulomb interaction of Mn (d) compared to Fe (d). The different chemical environments determine the location of the differently charged ions: with Mn occupying positions with (distorted) octahedral local symmetry, Mn ions prefer octahedrally coordinated sites in order to optimize their covalent bonding.

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