VOL 97, No. 8 (2024)

A method for obtaining a new composite material based on magmatic gabbro rock reinforced with basalt fiber is proposed. Laboratory samples were obtained and their properties (pycnometric density and Brinell hardness) were determined.

A method has been developed for one-sided etching of the inlet openings of channels of non-etched blanks of microchannel plates in dilute hydrofluoric acid. Blanks of microchannel plates MCP 18-10 were used in the work. The treatment was carried out in 0.2 n. hydrofluoric acid solution at room temperature without oscillation and mixing of the solution. The results obtained allow us to assert that the etching of the channel inlets is more than 10 % of the diameter of the MCP 18-10 channels, which increases the electronic transparency of the device.

The structure of matrix materials synthesized quenching sodium-rubidium aluminoborosilicate melts with the zirconium addition was studied using vibrational spectroscopy. The significant influence of zirconium on the ratio of the main structural units and the distribution of modifier cations was established in the glass structure. The results obtained were used to explain the change in the glass-melt transition temperature and the density of the material, and it is recommended for discussion in the selection of the composition and synthesis parameters of borosilicate matrix materials for the immobilization of high-level radioactive waste containing significant amounts of zirconium.

It has been shown that the modified sol-gel method (method Pechini) successfully synthesizes multielement oxides based on bismuth niobate, crystallizing in the pyrochlore structure type (space group Fd-3m). The synthesis temperature of a single-phase sample is 950 ?С, which is one hundred degrees lower than the calcination temperature in the traditional ceramic synthesis method. The average crystallite size, determined by X-ray diffraction, varies from 39 (850 ?С) to 48 nm (1050 ?С) depending on the sintering temperature. According to X-ray phase analysis, the unit cell parameter is 10.4872(6) ?. The results of elemental mapping indicate a uniform distribution of metal atoms on the surface of the sample, and X-ray energy dispersive analysis showed that the chemical composition of the synthesized sample corresponded to the specified theoretical composition.

The possibility of increasing the current density of a beam of charged particles (“focusing”) using tapered glass channels without involving external energy sources is currently being actively implemented for positively charged ions. In relation to electron beams, this possibility is not used due to the lack of experimental data on the process of grazing interaction of electron beams with a dielectric surface. It is necessary to study the degree of compression of the electron beam by tapering capillaries depending on their geometric parameters, as well as to study the time characteristics of the focusing process. In this work, an experimental study of the degree of compression of an electron beam with an energy of 10 keV was carried out using a glass tapering channel 15 mm long with an input/output internal diameter ratio of 1.15 mm/0.3 mm. An increase in the beam current density at the output for a capillary with the above parameters was demonstrated up to 2.7 times for a position where the channel axis is parallel to the axis of the original beam. Moreover, this increase in density is estimated for electrons that have lost no more than 1 keV of their initial energy. The stability of the process of electron transmission by a tapering capillary is also shown, regardless of the orientation of the capillary relative to the direction of the original beam.

The temperature regimes of the thermal extraction method for obtaining silicon dioxide from rice husk and various conditions of subsequent milling were investigated. Elemental, X-ray phase, petrographic analyses, electron and atomic force microscopy, differential scanning calorimetry, and laser granulometry were employed. The appearance of silicon dioxide was observed at a temperature of around 650 ?C, and its structure remained stable during pyrolysis and subsequent heat treatment in the presence of air. After heat treatment at 1000…1100 ?C, cristobalite was the predominant phase. The milling of the heat-treated products was associated with a significant loss of process efficiency due to the hereditary cellular structure of aggregates and their plastic character of destruction.

This article demonstrates the possibility of synthesizing a sulfur chemisorbent based on ZnO deposited on a granular ?-Al2O3 substrate by impregnation with an aqueous solution of zinc salt followed by thermal decomposition. The strength and textural characteristics of the resulting sorbent were studied using low-temperature nitrogen adsorption, X-ray diffraction, and scanning electron microscopy. The synthesized absorber has high strength and surface utilization compared to traditional ZnO-based sorbents used in natural gas processing. The proposed sorbent showed relatively high values of static sulfur capacity when absorbing H2S compared to industrial analogues of the zinc absorber.

Polyoxotungssilicates with the general formulas Cat4[SiW12O40] ? mH2O and Cat6[SiW11O39Ni(H2O)] ? nH2O, where Cat = Rb+, Cs+, (CH3)4N+, were synthesized. Using IR spectroscopy and X-ray phase analysis, it was shown that the compounds have the Keggin anion structure. When thermolysis of the resulting compounds in the temperature range 600…800 ?C, previously unknown phases are formed with the pyrochlore structure of the compositions Rb12/13Si2/13W22/13Ni2/13O6 and Cs12/13Si2/13W22/13Ni2/13O6 with unit cell parameters a = 10,284 and 10,309 ? and tungsten bronze Rb12/20Si3/20W36/20O6 and Si3/38W36/38O3. The synthesis of tungstosilicates with a pyrochlore and tungsten bronze structure by thermolysis of polyoxotungssilicates reduces their production temperature to 600…650 ?C and heating time to 1 hour, expands the range of chemical compositions and their morphological diversity.