Himiâ vysokih ènergij

In this study, a plasma-chemical method of methane conversion with CO₂ was considered as a potential means of producing hydrogen while simultaneously reducing carbon dioxide emissions. In order to achieve this, a series of experiments were conducted in order to evaluate the composition of the resulting fusion gas and the arc parameters. During the course of this work, it was found that modifying the volume of hydrogen present during the reaction resulted in an increase in the average mass temperature, which in turn led to an increase in the electrical conductivity of the arc. This finding suggests that the electrical parameters of the arc can be employed to estimate the quantity of hydrogen present in the resulting fusion gas.

This study employs molecular dynamics to investigate the conformational changes of a complex comprising two oppositely charged polyelectrolytes and a polyampholyte block copolymer adsorbed on the surface of a spherical metallic nanoparticle, as a function of its electrical charge. A mathematical model is presented for the rearrangement of two macromolecular shells of different signs spread on a charged spherical nanoparticle, together with an estimate of the stiffness of the polyelectrolyte chain as a function of its charge. Radial distributions of the average density of atoms of the polyelectrolyte complex and block copolymer situated on the surface of a charged spherical metallic nanoparticle are calculated. The polyelectrolytes with differing charges in the complex, along with the block copolymer, formed a tight envelope around the neutral spherical nanoparticle. As the absolute value of the nanoparticle charge increased, the macromolecular edge underwent swelling, resulting in the formation of two layers comprising differently charged polyelectrolytes or block copolymer fragments.

Colloidal quantum dots of CsPbBr₃ perovskites have been synthesised. The average size and polydispersity of the nanocrystals were determined to be 8.3 nm and 16%, respectively. The nanocrystals were employed in the fabrication of thin films via two distinct methods: drop casting and spin coating. The process of charge carrier transport was investigated through the use of laser femtosecond pump-probe spectroscopy. A proposed interpretation of the time-dependent shift of the lumen peak is presented. The Einstein–Smoluchowski equation was employed to estimate the mobility of charge carriers in the films.

The variation of the principal force parameters associated with polymethylmethacrylate ablation by means of continuous CO₂ laser radiation was subjected to investigation. The complex parameter, defined as the sum of the target weight and the reactive recoil force of the ablation flux, was measured using a force-measuring device with computer registration and a time resolution of 126.5 ms. The experimental data for the initial interval of 0-2 s were approximated by a model function, which enabled the identification of changes in the target weight and recoil force of the ablation flux during irradiation. The energy efficiency of the process in a low thrust jet engine (Cm = 115 μN/W) has been determined for the moment when the ablation rate reaches the stationary regime. This decreases with the laser irradiation time due to the formation of a crater with a concave surface and an increase in the gas pressure in the ablation chamber. It should be noted that the type of the ablation curve and, consequently, the approximating function for the initial stage of ablation are specific to each polymer and laser beam parameter.

The sensitivity and accuracy of volatile organic compound (VOC) identification can be enhanced through the manipulation of ionisation energy in electron impact ionisation mass spectrometric gas analysers. This is achieved by modulating the number of ions formed in the ion source. This paper presents a comparison of data obtained by electron impact ionisation at electron energy (EE) values in the range of 25–105 eV for a number of organic substances belonging to different classes of organic compounds. In order to interpret the dynamics of changes in the peak intensities of fragment ions, an analysis was conducted using similarity matrices based on different similarity metrics. This analysis demonstrated the influence of electron energy (EE) on the probability of formation of the main fragment particles of the studied substances, and consequently, on the similarity of the recorded mass spectrum with the reference mass spectrum from the database.

The oxidation of olefins С₂–С₄ in a barrier discharge in the presence of water has been investigated, with the formation of oxygen-containing compounds and various hydrocarbons С₁–С₅₊ of limited and unsaturated structure being observed. The initial olefin’s molecular weight and structure have been found to exert a significant influence on the direction of the reaction. In the ethylene-propylene-butylene series, the proportion of oxygen-containing compounds increases from 28.1, 74.3 and 66.7 wt%, respectively. The oxidation of isobutene isomasalic aldehyde and acetone, with a content of 53 and 21 wt. %, respectively, primarily yields the formation of these compounds. In the case of the oxidation of butene-1 and butene-2, the predominant products are butanol-2, with a yield of up to 26 wt. %.

The experimental investigation of atmospheric pressure streamer discharges on the water surface at two different polarities of voltage at the high-voltage electrode revealed several noteworthy findings. The discharge structure was photoregistered and subjected to statistical analysis. The results demonstrated that the discharges possess a complex structure comprising numerous branching channels. It was determined that the number of branching channels in discharges of negative polarity is approximately six times higher than the number of branching channels of positive polarity. Conversely, the mean branching angle of positive discharges is greater than that of negative polarity discharges. No branching angles exceeding 90° were observed, nor were any instances of intersection between different branches identified.