Dicyclopentadiene Polymerization in Solutions under the Action of Various Catalytic Systems

The kinetics of dicyclopentadiene polymerization in toluene solution under the action of different catalytic systems through adiabatic thermometry was investigated. Unlike cationic metathesis polymerization has a sufficiently large induction period associated with low speed by implantation monomer on carbine bond of catalyst. It has been shown that the rate of metathesis polymerization of dicyclopentadiene in comparable circumstances is about three times lower than the rate of cationic polymerization of the same monomer

Dicyclopentadiene Polymerization in Solutions under the Action of Various Catalytic Systems

The kinetics of dicyclopentadiene polymerization in toluene solution under the action of different catalytic systems through adiabatic thermometry was investigated. Unlike cationic metathesis polymerization has a sufficiently large induction period associated with low speed by implantation monomer on carbine bond of catalyst. It has been shown that the rate of metathesis polymerization of dicyclopentadiene in comparable circumstances is about three times lower than the rate of cationic polymerization of the same monomer

Oxidation and Structuring of Polydicyclopentadiene Thin Layers

It has been shown that polymeric film coatings derived from polydicyclopentadiene are subject to oxidation and structuring in air. Oxidation in air of double bonds in films gradually happens during several weeks and it comes amid an increase of adsorption band of carbonyl and hydroxyl groups in polymers infrared spectrums. Moreover, because of selective oxidation of cis-configured chains, structuring occurs around the double bonds in the polymer chain in polydicyclopentadiene films acquired by metathesis polymerization

Model of high school students professional education

The main idea of the article is to develop a model of high school students professional education, which includes target, content, technology, criterion-estimation and result components contributing to ensure the efficiency and the sequence of scientific-technique provision of educational process in High School. The aim of the developed model is the future competent specialist educating on the basis of his academic and extracurricular activities integration. This objective fulfillment is specified in the complex of interrelated tasks: students civil and patriotic education system forming; student self-government system improving on the basis of corporate culture and human individuality basic principles; conditions and prerequisites providing for the students world outlook forming in integrity of which his attitude to human values of social life is expressed; conditions providing for students tolerance development and the their common culture educating; innovative environment making with the aim to develop students creative abilities; students and University graduates social and professional adaptation and socialization organizational processes; organization of students legal, social and psychological protection system. This model provides the future competent specialists self-determination; the creation of psycho-pedagogical support of personal senses development in students' academic and extra-curricular activities in new forms of professional education building: from academic - to practical-oriented one; each student interest designing in extra-curricular activities

Cryptic Diversity in Paramecium multimicronucleatum Revealed with a Polyphasic Approach

Paramecium (Ciliophora) systematics is well studied, and about twenty morphological species have been described. The morphological species may include several genetic species. How-ever, molecular phylogenetic analyses revealed that the species diversity within Paramecium could be even higher and has raised a problem of cryptic species whose statuses remain uncertain. In the present study, we provide the morphological and molecular characterization of two novel Paramecium species. While Paramecium lynni n. sp., although morphologically similar to P. multimicronucleatum, is phylogenetically well separated from all other Paramecium species, Paramecium fokini n. sp. appears to be a cryptic sister species to P. multimicronucleatum. The latter two species can be distinguished only by molecular methods. The number and structure of micronuclei, traditionally utilized to discriminate species in Paramecium, vary not only between but also within each of the three studied species and, thus, cannot be considered a reliable feature for species identification. The geographic distribution of the P. multimicronucleatum and P. fokini n. sp. strains do not show defined patterns, still leaving space for a role of the geographic factor in initial speciation in Paramecium. Future findings of new Paramecium species can be predicted from the molecular data, while morphological characteristics appear to be unstable and overlapping at least in some species

Magnetic properties of the GdFeSi - GdTiSi solid solutions

The GdFe1-xTixSi, x=0-0.2 intermetallic compounds with a tetragonal crystal structure of the CeFeSi (P4/nmm)-type have been studied. It was obtained that the lattice parameter c and the Curie temperature increase quickly, whereas the lattice parameter a is almost unchanged in the system with increasing of Ti content. The GdFeSi compound is easily magnetized along the [001] axis, the field of magnetic anisotropy equals to ∼3.8 kOe at T = 90 K. The saturation magnetization does not change in the GdFe1-xTi x Si system. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 18-72-10098Support by RSF (Project No. 18-72-10098) is acknowledged

Large Magnetic Entropy Change in GdRuSi Optimal for Magnetocaloric Liquefaction of Nitrogen

The search for new magnetocaloric materials for application in magnetic refrigerants is highly motivated by high efficiency, reliability, and environmental safety. The values of the magnetocaloric effect MCE and the refrigerant capacity RC for the equiatomic GdRuSi compound were determined to be MCE = 10.7 and 4.94 J/kgK and RC = 336 and 92 J/kg with a change in the field of 0–50 and 0–17 kOe, respectively. These high values of MCE and RC for GdRuSi appear in the region of nitrogen liquefaction temperature of 77.4 K, due to which the compound can be useful in practice. The densities of states and magnetic moments of GdRuSi were calculated theoretically, taking into account strong electron correlations in the 4f Gd shell. The total magnetic moment of GdRuSi was found to be composed of the Gd moment only with the value calculated in very good agreement with the experimental one. © 2023 by the authors.Ministry of Education and Science of the Russian Federation, Minobrnauka: 122021000034-9, 122021000039-4; Russian Science Foundation, RSF: 18-72-10098The results of Section 1, Section 2, Section 3.1 and Section 3.2 (magnetic properties and electronic structure calculations) were obtained within the grant of the Russian Science Foundation No. 18-72-10098, https://rscf.ru/en/project/18-72-10098/ (accessed on 29 December 2022). The results of Section 3.3 were obtained within the state assignment of Ministry of Science and Higher Education of the Russian Federation (themes “Magnet” No. 122021000034-9 and “Electron” No. 122021000039-4)

Statistics of magnetic field measurements in OBA stars and the evolution of their magnetic fields

© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim We review the measurements of magnetic fields of OBA stars. Based on these data, we confirm that magnetic fields are distributed according to a lognormal law with mean log B = − 0.5 (B in kG) with a standard deviation σ = 0.5. The shape of the magnetic field distribution (MFD) is similar to that for neutron stars. This finding favors the hypothesis that the magnetic field of a neutron star is determined mainly by the magnetic field of its predecessor, namely the massive OB star. Further, we model the evolution of an ensemble of magnetic massive stars in the Galaxy. We use our own population synthesis code to obtain the distribution of stellar radii, ages, masses, temperatures, effective magnetic fields, and magnetic fluxes from the pre-main-sequence (PMS) via zero-age main sequence (ZAMS) up to the terminal-age main sequence stages. A comparison of the MFD obtained in our model with that obtained from the recent measurements of the stellar magnetic field allows us to conclude that the evolution of magnetic fields of massive stars is slow if not absent. The shape of the real MFD shows no indications of the magnetic desert proposed previously. Based on this finding, we argue that the observed fraction of magnetic stars is determined by physical conditions at the PMS stage of stellar evolution

INFLUENCE OF THE TECHNOLOGICAL SCHEME OF PRODUCTION OF EXTRUSION TUBES ON METALLOGRAPHIC FEATURES AND MECHANICAL PROPERTIES OF COLD FORMED TUBES

Работа посвящена оценке влияния технологической схемы производства передельных горячепрессованных труб из титанового псевдо-α сплава Ti–3Al–2.5V [1] на металлографические особенности и механические свойства холоднодеформированных труб готового размера. Оценка влияния проводилась с целью моделирования процесса производства холоднодеформированных труб по технологии, включающей в себя изготовление горячепрессованных передельных труб размерами 90,0 × 20,0 и 90,0 × 23,5 мм и последующую холодную прокатку труб размерами 38,1 × 5,36 мм в условиях ПАО «ТМК».The work is devoted to the evaluation of the effect of the technological scheme for the production of extrusion tubes from Ti–3Al–2.5V titanium pseudo-α alloy [1] on metallographic features and mechanical properties of cold-formed tubes of finished size. Impact evaluation was carried out to simulate the production process of cold-deformed tubes using a technology including the production of extrusion conduits with dimensions of 90.0 × 20.0 and 90.0 × 23.5 mm and subsequent cold formed of tubes measuring 38,1 × 5,36 mm in conditions of PJSC TMK