On physical properties of nanoparticles: size effect and scale of nanoobjects

A transition border between macroscopic and nanoscale states of solids associated with change of its physical properties is certain to exist. The change of mechanical, magnetic, thermal and other properties of nanoparticles may be due to the surface tension, decrease in coordination number in the topsurface layer, rebuilding of the electron shell structure, change of the symmetry group of the crystal lattice and the binding energy

NEW TECHNOLOGIES iN RECONSTRUCTIVE SURGERY OF INJURIES AND CICATRICIAL STENOSES OF TRACHEA

The results of treatment of 9 patients with mechanical injury of trachea and of 22 patients with cicatricial stenoses of trachea are presented, in this article. 18 patients had. staged, reconstructive and plastic operations at the cicatricial stenosis, 2 patients had. endoscopic recanalization of tracheal lumen and. 2 patients had. sleeve resection of trachea with, anastomosis. An. original medical complex including argon-plasmatic, cryosurgical and. lymphotropic technologies. In all cases we managed, to recover respiratory tract integrity and. to provide adequate breath through, natural respiratory tract

Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.Comment: 24 pages, 15 figure

A Survey of Experimental Research on Contests, All-Pay Auctions and Tournaments

Many economic, political and social environments can be described as contests in which agents exert costly efforts while competing over the distribution of a scarce resource. These environments have been studied using Tullock contests, all-pay auctions and rankorder tournaments. This survey provides a review of experimental research on these three canonical contests. First, we review studies investigating the basic structure of contests, including the contest success function, number of players and prizes, spillovers and externalities, heterogeneity, and incomplete information. Second, we discuss dynamic contests and multi-battle contests. Then we review research on sabotage, feedback, bias, collusion, alliances, and contests between groups, as well as real-effort and field experiments. Finally, we discuss applications of contests to the study of legal systems, political competition, war, conflict avoidance, sales, and charities, and suggest directions for future research. (author's abstract

Signal delivery system in a subarray of Giant Ukrainian Radio Telescope

Radio astronomy deals with the weakest signals received by a radio electronic device, and, as a result, it is very complicated problem to maintain appropriate SNR while transferring signal from the antenna output to receiver's input. In this paper, a system for delivering the radio astronomical signals from dipole terminals to ADC input of Giant Ukrainian Radio Telescope (GURT) is described. Examples of the received signal spectra in wide frequency range are shown

Periodic structures formed on the surface of silicon monocrystal treated with compression plasma flow

Рассмотрено образование периодических структур под воздействием компрессионного плазменного потока на поверхности монокристаллической кремниевой пластины как результат зарождения и развития гидродинамической неустойчивости типа неустойчивости Кельвина–Гельмгольца, вызванной течением плазмы вдоль поверхности пластины. Предложено описание кремниевого расплава с помощью уравнений магнитной гидродинамики для идеальной несжимаемой жидкости. Для анализа стабильности системы плазма–расплав использована линейная теория устойчивости, адаптированная для случая изменяющейся со временем глубины расплавленного слоя. Получено аналитическое выражение, которое связывает период модулированной поверхности пластины с величинами, характеризующими течение плазмы.Formation of periodic submicron structures on the surface of silicon wafer under the action of compression plasma flow is considered to be a manifestation of Kelvin–Helmholtz hydrodynamic instability caused by the plasma flows along the melt free surface. The melt flow is described with the help of motion equations for an ideal non-compressible conducting medium. Linear stability theory modified to include the time-dependent melt depth is employed to analyze stability of plasma-melt system. The expression, which relates the modulated surface period and plasma parameters, is obtained