Novel relativistic plasma excitations in a gated two-dimensional electron system

The microwave response of a two-dimensional electron system (2DES) covered by a conducting top gate is investigated in the relativistic regime for which the 2D conductivity $\sigma_{2 \rm{D}} > c/2\pi$. Weakly damped plasma waves are excited in the gated region of the 2DES. The frequency and amplitude of the resulting plasma excitations show a very unusual dependence on the magnetic field, conductivity, gate geometry and separation from the 2DES. We show that such relativistic plasmons survive for temperatures up to 300 K, allowing for new room-temperature microwave and terahertz applications.Comment: 9 pages, 7 figure

Volitional self-regulation and emotional burnout of professional sambo-athletes who suffered from sports injuries

Objective: to study the level of volitional self-regulation and emotional burnout in male sambo-athletes who underwent sports injuries of various degrees of severity. Materials and methods: 60 male sambo-athletes were examined. They were divided into 3 groups of 20 people in each group based on types of sports injuries. Results: significantly (p=0.001) lower level of volitional self-regulation was found in the third group who underwent more injuries (total scale: Q1=6,0; Me=8,0; Q3=10,0; «perseverance»: Q1=5,0; Me=5,5; Q3=8,0; «self-control»: Q1=4,0; Me=4,5; Q3=5,0). More pronounced emotional burnout occured in athletes who had more injuries (Q1=64,5; Me=69,0; Q3=71,0; p=0,001). Inadequate emotional response and emotional and moral disorientation was leveled down with aggravation of the severity of injuries (Q1=25,0; Me=44,0; Q3=61,0; p=0,039). Adaptation systems strain is manifested by a marked emotional exhaustion and decrease in volitional self-regulation with an increase in the number of injuries. Conclusions: if incidence and severity of injuries increases in sambo-athletes the level of volitional self-regulation reduces and emotional burnout occurs, which is characterized by the stress of the system of psychological adaptation

Motion capture systems: medical and technical assessment of the current stage of technology development. Literature review

Objective: to conduct a comparative medical and technical analysis of existing motion capture systems.Materials and methods: open data sources (e-library, Scopus, PubMed, etc.) were used as a scientific base to achieve this aim. The search depth is not limited.Results: information about marker-free and marker motion capture systems, including inertial, mobile, mechanical, optoelectronic, magnetic and systems using virtual reality technology, is consistently presented. A comparative analysis of the medical and technical characteristics of the presented systems was carried out.Conclusion: it is shown that motion capture systems are a promising direction for the development of a whole group of tools for the diagnosis of locomotor function, which can be successfully integrated into a sports medicine clinic. Motion capture systems vary in their technical parameters, which requires a deep analytical approach in their use to solve different clinical problems

Piezo-Responsive Hydrogen-Bonded Frameworks Based on Vanillin-Barbiturate Conjugates

A concept of piezo-responsive hydrogen-bonded π-π-stacked organic frameworks made from Knoevenagel-condensed vanillin–barbiturate conjugates was proposed. Replacement of the substituent at the ether oxygen atom of the vanillin moiety from methyl (compound 3a) to ethyl (compound 3b) changed the appearance of the products from rigid rods to porous structures according to optical microscopy and scanning electron microscopy (SEM), and led to a decrease in the degree of crystallinity of corresponding powders according to X-ray diffractometry (XRD). Quantum chemical calculations of possible dimer models of vanillin–barbiturate conjugates using density functional theory (DFT) revealed that π-π stacking between aryl rings of the vanillin moiety stabilized the dimer to a greater extent than hydrogen bonding between carbonyl oxygen atoms and amide hydrogen atoms. According to piezoresponse force microscopy (PFM), there was a notable decrease in the vertical piezo-coefficient upon transition from rigid rods of compound 3a to irregular-shaped aggregates of compound 3b (average values of d33 coefficient corresponded to 2.74 ± 0.54 pm/V and 0.57 ± 0.11 pm/V), which is comparable to that of lithium niobate (d33 coefficient was 7 pm/V). © 2022 by the authors.2.1.06.03, 20211572; Russian Foundation for Basic Research, РФФИ: 20-53-00043-Bel_a; Ministry of Science and Technology, Taiwan, MOST: 19-52-06004 MNTI_a; Ural Federal University, UrFU: 2968; Ministry of Science and Higher Education of the Russian Federation: 075-15-2021-677The work was supported by the Russian Foundation for Basic Research (RFBR, project no. 20-53-00043-Bel_a) and the PFM measurements were done under RFBR and MOST project no. 19-52-06004 MNTI_a. The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University (Reg. No. 2968), which is supported by the Ministry of Science and Higher Education RF (project No. 075-15-2021-677), was used. T.V.S. acknowledges the support from the State Program of Scientific Researchers of Belarus (research issue 2.1.06.03, state registration number: 20211572)