In this paper a group theoretic version of Dehn surgery is studied. Starting with an arbitrary relatively hyperbolic group G we define a peripheral filling procedure, which produces quotients of G by ...imitating the effect of the Dehn filling of a complete finite volume hyperbolic 3-manifold M on the fundamental group π^sub 1^(M). The main result of the paper is an algebraic counterpart of Thurston's hyperbolic Dehn surgery theorem. We also show that peripheral subgroups of G 'almost' have the Congruence Extension Property and the group G is approximated (in an algebraic sense) by its quotients obtained by peripheral fillings. PUBLICATION ABSTRACT
Fast multispectral deep fusion networks V. Osin; A. Cichocki; E. Burnaev
Bulletin of the Polish Academy of Sciences. Technical Sciences,
12/2018, Letnik:
66, Številka:
No 6 (Special Section on Deep Learning: Theory and Practice)
Journal Article
The article presents the results of an empirical study comparing the socio-psychological adaptation of migrant children and local children studying in secondary school No. 20 of Penza. A theoretical ...analysis was carried out and the problem of adaptation of migrant children at school was justified. Through theoretical analysis, it has been established that the difficulties in the socio-psychological adaptation of migrant children are quite often due to the inability to interact with the local population, problems in communication, which in turn stimulate the growth of anxiety, hostility, distrust of the new living conditions and the environment, etc. As a result of an empirical study, differences in the indicators of socio-psychological adaptation of migrant children and local children were revealed. In particular, migrant children have a high level of aggressiveness, hostility, the following forms of aggression are more expressed: physical, verbal and indirect. They are characterized by the use of physical strength, foul language, the spread of gossip, rumors, negativism, irritation, suspicion and insult. Local children have lower indicators of personal and reactive anxiety, selfesteem, they are more often than migrant children in school classes have high social status (active) and very rarely low (ignored). At the same time, almost half of the migrant children occupy ignored and isolated positions in the group. Among all the children (local and migrants), the impuntive orientation of reactions in the frustration situation is dominant, but migrant children still have an extrapunitive orientation and less expressed intropunitive orientation.
Methods and samples have been developed and improved for comprehensive evaluation of the operational properties of materials for deposited elements and tools for pressure metal processing. In ...particular, the method of assessing the wear resistance of deposited metal at room (20°C) and elevated (600°C) temperatures, as well as the thermal resistance of deposited metal was improved. Designs of samples and optimal test modes, which simulate their real operating conditions, were chosen. The introduction of the boron microadditives in the amount of 0.01% leads to an increase in the operational properties of the deposited 25Kh5FMS and 35V9Kh3SF steels in 1.2–1.6 times. According to these results, the composition of the flux cored FCW-Dep-25Kh5FMS and FCW-Dep-35V9Kh3SF wires was improved due to the addition of FMI-2 ligature containing boron.
The prospects for using ceramic composite materials in place of metallic materials in heat-loaded units in advanced aircraft are examined. The manufacture of silicon carbide based ceramic composite ...materials, reinforced with filamentary crystals (whiskers), by means of hot-pressing and spark plasma sintering using oxide and nitride sintering additives was investigated. A complex of physical-mechanical and thermal properties of composites was investigated.
The authors introduce and study the notions of hyperbolically embedded and very rotating families of subgroups. The former notion can be thought of as a generalization of the peripheral structure of ...a relatively hyperbolic group, while the latter one provides a natural framework for developing a geometric version of small cancellation theory. Examples of such families naturally occur in groups acting on hyperbolic spaces including hyperbolic and relatively hyperbolic groups, mapping class groups, Out(F_n), and the Cremona group. Other examples can be found among groups acting geometrically on CAT(0) spaces, fundamental groups of graphs of groups, etc. The authors obtain a number of general results about rotating families and hyperbolically embedded subgroups; although their technique applies to a wide class of groups, it is capable of producing new results even for well-studied particular classes. For instance, the authors solve two open problems about mapping class groups, and obtain some results which are new even for relatively hyperbolic groups.
The results of the development and the main characteristics of a new generation of semiconductor current switches (250 kA/25 kV/70 C) based on assemblies of series-connected reverse switched-on ...dynistors (RSDs) are presented. The methods for increasing the switched power and increasing the service life and reliability of RSD switches with maintenance of the previously accepted weight and size indicators were studied. The problem was solved by reducing the RSD power loss and increasing the resistance of the contact connections to the effects of high-power current pulses. The switch design was modernized and the silicon structure was optimized; a new technology for low-temperature connections in the silicon–metal system with the use of silver was developed, thus making it possible to double the active contact area and improve the load characteristics and service life of the new switches. The operating and maximum permissible values of the starting and switched currents were determined. The results of the operation of RSD switches in capacitive energy-storage devices of high-power laser devices are presented. Based on the results of life tests, the service life of new devices was assessed.
The results of experimental studies on the fabrication of prototypes of ceramic composite cladding elements of the flame tube for a combustion chamber are presented. The structure and ...physicomechanical properties of the prototype samples were investigated. High-temperature bench tests of prototypes were performed as part of an experimental sample of a flame tube with a similar design.
This paper presents the results of studying the production of molybdenum-tungsten alloys by spark plasma sintering at various process conditions, as well as the processes of material compaction and ...structure formation. A comparative analysis of compactability of molybdenum-tungsten alloys produced by spark plasma sintering and sintering in hydrogen was performed. It was shown that a relative density of > 95% can be achieved at a temperature of 1,800°C and external pressure of 50 MPa.
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