Passivation of metal nanopowders obtained by electric explosion of semiconductors

The influence of composition and gas flow rate at passivation on content of unoxidized metal, particle size and temperature on the metal nanopowder layer obtained by the method of semiconductor electric explosion has been studied. It is shown that the time of forced passivation can be tens times less in comparison with passivation at spontaneous gas diffusion in powder layer

Faster radial strain relaxation in InAs-GaAs core-shell heterowires

The structure of wurtzite and zinc blende InAs-GaAs (001) core-shell nanowires grown by molecular beam epitaxy on GaAs (001) substrates has been investigated by transmission electron microscopy. Heterowires with InAs core radii exceeding 11 nm, strain relax through the generation of misfit dislocations, given a GaAs shell thickness greater than 2.5 nm. Strain relaxation is larger in radial directions than axial, particularly for shell thicknesses greater than 5.0 nm, consistent with molecular statics calculations that predict a large shear stress concentration at each interface corner

Orthogonal Decomposition of Some Affine Lie Algebras in Terms of their Heisenberg Subalgebras

In the present note we suggest an affinization of a theorem by Kostrikin et.al. about the decomposition of some complex simple Lie algebras ${\cal G}$ into the algebraic sum of pairwise orthogonal Cartan subalgebras. We point out that the untwisted affine Kac-Moody algebras of types $A_{p^m-1}$ ($p$ prime, $m\geq 1$), $B_r, \, C_{2^m}, D_r,\, G_2,\, E_7,\, E_8$ can be decomposed into the algebraic sum of pairwise or\-tho\-go\-nal Heisenberg subalgebras. The $A_{p^m-1}$ and $G_2$ cases are discussed in great detail. Some possible applications of such decompositions are also discussed.Comment: 16 pages, LaTeX, no figure

Properties of equations of the continuous Toda type

We study a modified version of an equation of the continuous Toda type in 1+1 dimensions. This equation contains a friction-like term which can be switched off by annihilating a free parameter \ep. We apply the prolongation method, the symmetry and the approximate symmetry approach. This strategy allows us to get insight into both the equations for \ep =0 and \ep \ne 0, whose properties arising in the above frameworks are mutually compared. For \ep =0, the related prolongation equations are solved by means of certain series expansions which lead to an infinite- dimensional Lie algebra. Furthermore, using a realization of the Lie algebra of the Euclidean group $E_{2}$, a connection is shown between the continuous Toda equation and a linear wave equation which resembles a special case of a three-dimensional wave equation that occurs in a generalized Gibbons-Hawking ansatz \cite{lebrun}. Nontrivial solutions to the wave equation expressed in terms of Bessel functions are determined. For \ep\,\ne\,0, we obtain a finite-dimensional Lie algebra with four elements. A matrix representation of this algebra yields solutions of the modified continuous Toda equation associated with a reduced form of a perturbative Liouville equation. This result coincides with that achieved in the context of the approximate symmetry approach. Example of exact solutions are also provided. In particular, the inverse of the exponential-integral function turns out to be defined by the reduced differential equation coming from a linear combination of the time and space translations. Finally, a Lie algebra characterizing the approximate symmetries is discussed.Comment: LaTex file, 27 page

Topological gravity on plumbed V-cobordisms

An ensemble of cosmological models based on generalized BF-theory is constructed where the role of vacuum (zero-level) coupling constants is played by topologically invariant rational intersection forms (cosmological-constant matrices) of 4-dimensional plumbed V-cobordisms which are interpreted as Euclidean spacetime regions. For these regions describing topology changes, the rational and integer intersection matrices are calculated. A relation is found between the hierarchy of certain elements of these matrices and the hierarchy of coupling constants of the universal (low-energy) interactions. PACS numbers: 0420G, 0240, 0460Comment: 29 page

ТВЕРДОКОНТАКТНЫЕ ПОТЕНЦИОМЕТРИЧЕСКИЕ СЕНСОРЫ НА ОСНОВЕ НАНОЧАСТИЦ СЕРЕБРА В СУПРАМОЛЕКУЛЯРНОЙ МАТРИЦЕ ДЛЯ ОПРЕДЕЛЕНИЯ ГАЛОГЕНИД-ИОНОВ

Determination of halogenide ions in pharmaceuticals and various waters is an actual task for the modern analytical chemistry. In the current work, solid-contact potentiometric sensor, based on the glassy carbon electrode covered with the layer of electropolymerized polyaniline and suspension of silver nanoparticles in the matrix of thiacalix[4]arene derivative bearing terminal catechol groups, has been described. The suspension was obtained by the chemical reduction of silver ions with the thiacalix[4]arene and drop casted on the polyaniline layer. The sensor showed potentiometric response to chloride-, bromide and iodide ions. For the simultaneous determination of iodide and bromide ions, a multi-sensor system, consisting of four electrodes with the different volumes of the suspension placed on the polyaniline layer, has been developed. The possibility of the response prediction within the simple additive model was found for the set of the iodide and bromide mixtures. In a similar manner, simultaneous determination of both ions in the variable mixtures has been performed. The multi-sensor system was tested during the determination of iodides in iodine containing pharmaceuticals and the determination of iodide and bromide ions in the artificial mineral water samples. Ionic chromatography was chosen as the comparison method. Sensors made it possible to determine from 0.1 μM to10 mMiodide and bromide ions in mixtures. The proposed approach and solid-contact potentiometric sensors can be used in the analysis of ion content of the waters and in control of the production and storage conditions of pharmaceuticals.Key words: Solid-contact sensor, ionometry, halogenide determination, polyaniline, multisensory system, additive model of the responseDOI: http://dx.doi.org/10.15826/analitika.2022.26.3.002M.I. Sorvin, A.A. Saveliev, I.I. Stoikov, S.V. Belyakova, G.A. Evtugyn Kazan (Volga-Region) federal university, Russian Federation, 420008, Kazan, Kremlevskaya Str. 18Определение содержания галогенид-ионов в лекарственных препаратах и водах различного назначения представляет собой актуальную задачу современной аналитической химии. В работе представлен твердоконтактный потенциометрический сенсор на основе стеклоуглеродного электрода, покрытого слоем электрополимеризованного анилина и суспензией наночастиц серебра в матрице производного тиакаликс[4]арена с концевыми пирокатехиновыми группами. Суспензию получали, химически восстанавливая ионы серебра тиакаликс[4]ареном и капельно наносили на слой полианилина. Сенсор демонстрировал потенциометрический отклик на хлорид-, бромид и йодид-ионы. Для одновременного определения йодид- и бромид ионов предложено использовать мультисенсорную систему из четырех электродов, отличающихся составом и объемом суспензии, наносимой на полимерную подложку полианилина. На выборке смесей йодид- и бромид-ионов показана возможность предсказания отклика на основе простой аддитивной модели. Аналогичным образом проводили одновременное определение обоих ионов в смесях произвольного состава. Мультисенсорная система была апробирована на определении йодид-ионов в йодсодержащих медицинских препаратов, а также йодид- и бромид-ионов в искусственных образцах минеральной воды. Методом сравнения выступала ионная хроматография. Сенсоры позволяют проводить определение от 0.1 мкМ до10 мМйодид- и бромид-ионов в смесях. Предложенный подход и твердоконтактные потенциометрические сенсоры могут найти применение в анализе ионного состава вод и контроля производства и хранения лекарственных препаратов.Ключевые слова: Твердоконтактный сенсор, ионометрия, определение галогенидов, полианилин, мультисенсорная система, аддитивная модель откликаDOI: http://dx.doi.org/10.15826/analitika.2022.26.3.00

FEATURES OF THE PROFESSION LOSS CRISIS IN OLDER TEACHERS

Introduction. The relevance of the current research in the features of the profession loss crisis among older teachers is due to the need to develop the methods of psychological support for their professional development in the conditions of growing demands on the educational process. The aim of the study is to identify the features of the profession loss crisis among older teachers. In the course of the study, the authors put forward the following hypotheses. The features of the profession loss crisis include two scenarios, which are reflected in the psychological state of teachers and their attitude towards their own profession. The positive scenario is characterised by physical and psychological health, hardiness and psychological well-being, while the negative scenario is characterised by deterioration in physical and mental health, reduced hardiness and psychological well-being. Methodology and research methods. The methodological basis for the study was the concept of professional development by E. F. Zeer and E. E. Symaniuk, as well as the approaches to examining the psychological characteristics of the crisis of late age; psycho-aging changes at a later age; stages of professional development; features of experiencing crises. The study involved 956 teachers working in educational organisations of the Sverdlovsk region (58 men and 898 women). The average age of the respondents was 57.9 years. The features of the profession loss crisis were determined using the biographical method, which allowed the authors to consider the dynamic process of professional development and highlight the psychological characteristics of the crisis based on content analysis. The biographical questionnaire contained questions aimed at identifying general social and professional information, determining the characteristics of options, professional activities, retirement and plans for future life, as well as determining the success of a professional biography. The following methods were used: test of hardiness in the adaptation of E. N. Osin and E. I. Rasskazova; method of quality-of-life SF-36; T. V. Kornilova's new questionnaire of tolerance to uncertainty; scale of psychological well-being by K. Riff as adapted by T. D. Shevelenkova, P. P. Fesenko; questionnaire by K. Zamfir "Motivation of professional activity" in the modification of A. A. Rean. Data processing was carried out in the RStudio program. To highlight the options for the course of the crisis, cluster analysis was used. Welch's t-test was applied to compare the groups with each other. The one-sample Student's t-test was used to compare groups with standard indicators. Results. It was revealed that the profession loss crisis can proceed according to two scenarios, each of which has its own characteristics. In a positive scenario (about 3/4 of cases), the indicators of physical and psychological health, vitality and psychological well-being do not differ from the normative values. At the same time, teachers generally have a good attitude towards their profession and have plans to continue working in profession and learning something new. In the negative scenario of the crisis, the indicators of resilience and psychological well-being are at the lower limit of the norm, and the indicators of physical and mental health are significantly lower than the norm. Teachers are much more likely to note disappointment in the profession and, in general, have a more negative attitude towards it than the representatives of the positive group. Among them, there are significantly more of those who plan to leave the profession and fewer of those who plan to stay in the profession and learn something new. Scientific novelty consists in the enrichment of psychological science with knowledge about the features of the profession loss crisis among older teachers working at different levels of education in the context of the professional development of the individual. Practical significance. The presented results can be employed in educational organisations to develop programmes for the prevention of the profession loss crisis among teachers and recommendations for teachers of late maturity to maintain their active professional longevity. © 2022 Russian State Vocational Pedagogical University. All rights reserved.Russian Foundation for Basic Research, РФФИ: 20-013-00790Acknowledgements. The present research was carried out with the financial support of the Russian Foundation for Basic Research (RFBR) in the framework of the research project № 20-013-00790 “Overcoming the Professional Loss Crisis Experienced by Teachers in the Period of Late Adulthood”

SDiff(2) Toda equation -- hierarchy, τ\tau function, and symmetries

A continuum limit of the Toda lattice field theory, called the SDiff(2) Toda equation, is shown to have a Lax formalism and an infinite hierarchy of higher flows. The Lax formalism is very similar to the case of the self-dual vacuum Einstein equation and its hyper-K\"ahler version, however now based upon a symplectic structure and the group SDiff(2) of area preserving diffeomorphisms on a cylinder $S^1 \times \R$. An analogue of the Toda lattice tau function is introduced. The existence of hidden SDiff(2) symmetries are derived from a Riemann-Hilbert problem in the SDiff(2) group. Symmetries of the tau function turn out to have commutator anomalies, hence give a representation of a central extension of the SDiff(2) algebra.Comment: 16 pages (``vanilla.sty" is attatched to the end of this file after ``\bye" command

A class of nonlinear wave equations containing the continuous Toda case

We consider a nonlinear field equation which can be derived from a binomial lattice as a continuous limit. This equation, containing a perturbative friction-like term and a free parameter $\gamma$, reproduces the Toda case (in absence of the friction-like term) and other equations of physical interest, by choosing particular values of $\gamma$. We apply the symmetry and the approximate symmetry approach, and the prolongation technique. Our main purpose is to check the limits of validity of different analytical methods in the study of nonlinear field equations. We show that the equation under investigation with the friction-like term is characterized by a finite-dimensional Lie algebra admitting a realization in terms of boson annhilation and creation operators. In absence of the friction-like term, the equation is linearized and connected with equations of the Bessel type. Examples of exact solutions are displayed, and the algebraic structure of the equation is discussed.Comment: Latex file + [equations.sty], 22 p

Hamiltonian submanifolds of regular polytopes

We investigate polyhedral $2k$-manifolds as subcomplexes of the boundary complex of a regular polytope. We call such a subcomplex {\it $k$-Hamiltonian} if it contains the full $k$-skeleton of the polytope. Since the case of the cube is well known and since the case of a simplex was also previously studied (these are so-called {\it super-neighborly triangulations}) we focus on the case of the cross polytope and the sporadic regular 4-polytopes. By our results the existence of 1-Hamiltonian surfaces is now decided for all regular polytopes. Furthermore we investigate 2-Hamiltonian 4-manifolds in the $d$-dimensional cross polytope. These are the "regular cases" satisfying equality in Sparla's inequality. In particular, we present a new example with 16 vertices which is highly symmetric with an automorphism group of order 128. Topologically it is homeomorphic to a connected sum of 7 copies of $S^2 \times S^2$. By this example all regular cases of $n$ vertices with $n < 20$ or, equivalently, all cases of regular $d$-polytopes with $d\leq 9$ are now decided.Comment: 26 pages, 4 figure