702 research outputs found
The role of information technology training in the conditions of informatization education
This article presents the role of informatization of education in the university. The positive aspects of the use of information technology in the educational process of both students and teachers are also consideredВ настоящей статье представлена роль информатизации образования в ВУЗе. Также рассмотрены положительные моменты использования информационных технологий в учебном процессе как студентов, так и преподавателе
New Late Viséan and Early Serpukhovian ammonoids in the Verkhnyaya Kardailovka section (Eastern Slope of the South Urals)
© 2017, Pleiades Publishing, Ltd. New Late Viséan and Early Serpukhovian ammonoids are described from the Verkhnyaya Kardailovka section (South Urals, Bashkortostan). The ammonoid assemblages allow the recognition of the Hypergoniatites−Ferganoceras Genozone and a correlation with the synchronous zonations of North Africa, Spain, and China. The new species Ferganoceras constrictum sp. nov., Dombarites clemens sp. nov., and Hypergoniatites kardailovkensis sp. nov. are described
Parallel algorithms for simulation of ultrashort pulse propagation in turbid media
Parallel mesh algorithm to simulate the propagation of an ultrashort pulse from a point source with small aperture in turbid media is presented. The algorithm is applied to a particular case of propagation of infrared pulsed laser
radiation in biotissue. Comparison of obtained results with Monte Carlo simulation ones is performed
Cephalopod embryonic shells as a tool to reconstruct reproductive strategies in extinct taxa
© 2017 Cambridge Philosophical Society.An exhaustive study of existing data on the relationship between egg size and maximum size of embryonic shells in 42 species of extant cephalopods demonstrated that these values are approximately equal regardless of taxonomy and shell morphology. Egg size is also approximately equal to mantle length of hatchlings in 45 cephalopod species with rudimentary shells. Paired data on the size of the initial chamber versus embryonic shell in 235 species of Ammonoidea, 46 Bactritida, 13 Nautilida, 22 Orthocerida, 8 Tarphycerida, 4 Oncocerida, 1 Belemnoidea, 4 Sepiida and 1 Spirulida demonstrated that, although there is a positive relationship between these parameters in some taxa, initial chamber size cannot be used to predict egg size in extinct cephalopods; the size of the embryonic shell may be more appropriate for this task. The evolution of reproductive strategies in cephalopods in the geological past was marked by an increasing significance of small-egged taxa, as is also seen in simultaneously evolving fish taxa
Influence of a high-power pulsed ion beam on the mechanical properties of corundum ceramics
The mechanical properties of near-surface layers of corundum ceramics treated by high-power pulsed ion beam of carbon are investigated. The samples for investigation were prepared from corundum substrate, which is usually used in microelectronic. The ion treatment was carried out at the TEMP-4M facility under the following conditions: an accelerating voltage of 160-200 keV, the current density in the pulse varied within 15-85 A/cm{2} . It was found that ion irradiation changes the structure and properties of near-surface layers of corundum ceramics. At the same time, melting and erosion of the surface layer takes place. These processes are accompanied by the formation of a network of microcracks. Microcracks are propagated only by the depth of melting layer. The mechanical properties were measured using a NanoTest600 nanohardness testing instrument. It was found that the nanohardness depends of the treatment modes. At a current density of 15A/cm{2} , with an increase treatment dose, the nanohardness of the irradiated surface layer increases in comparison with the initial value before irradiation. At higher current densities, the nanohardness of irradiated ceramics decreases relatively to the initial value before irradiation. The dependences of nanohardness off the irradiation dose in this case have the view of a curves with a minimum at irradiation doses of 2.5∙1014 and 1.3∙1014 cm{-2} , for current densities of 50 and 85 A/cm{2} , respectively
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