Efficiency of the terahertz spin-injection emitter

The energy efficiency of the spin-injection emitter based on the rod-film ferromagnetic structure with a point contact between the components in the terahertz frequency range is experimentally estimated. The film material substantially affects the efficiency. A concentrator of magnetic flux is proposed for an increase in the efficiency. The experimental estimations allow the quantum yield of the emitter that is greater than unity. This result indicates significant contribution of the stimulated radiative transitions.     

A STUDY OF COMPLEXES YIELDED BY HNO3 Fe(III)AND Eu(III) EXTRACTION FROM NITRATE MEDIA WITH ACIDIC Zr(IV) AND Hf( IV) DI-2-ETHILHEXYLPHOSPHATES

Possible reasons for significant enhancement of solvent extraction of some metals with dialkylphos-phoric acids in the presence of Zr(IV) and Hf(IV) are critically discussed, taking into consideration both the literature and the autors'data on the structure of acidic salts formed by these acids with Zr(IV) and Hf(IV). The chemistry of extraction of nitric acid, FeUII) and Eu ( I I I ) with Zr(IV) and Hf(IV) salts of di-2-ethy1hexy1 phosphoric acid (HX) has been studied using IR and ³¹P NMR spectroscopy. Nitric acid is extracted by these salts due to interaction with their acceptor sites that results in the formation of a new polymeric extractant with bidentate anions of two types, (X-H-X)- and (X-H-N0₃)_. Protons of these groups can be exchanged with metal cations extracted, e.g., with Fe(III) or Eu(I 11 ), heteropolynuc1 ear complexes with non-equivalent (chelating and bridge) N0₃ anions being formed during the extraction. The composition and structure of coordination polyhedrons formed around Zr(IV), Hf(IV), Fe(III) and Eu(III) have been determined. The reasons for a higher extraction ability of the salts studied for Fe(III) and Eu(III) versus D2EHPA itself are described.     

Modeling the deformation of RBMK graphite columns surrounding a damaged cell with a ruptured channel pipe taking aging into account

The results of modeling of the deformation of RBMK graphite columns surrounding a damaged cell with a rupture channel tube and analysis of the possibility of multiple rupture of the tubes in such columns as a result of the action of the steam–water mixture flowing out of the rupture are presented. The aging of the masonry is taken into account in connection with RBMK service life extension. The calculations of the kinetics of the deflections of the columns, surrounding a damaged cell, and the strength of the channel tubes of these columns showed that multiple ruptures of tubes following an emergency situation in accidents with an initial rupture of the RBMK process channel are impossible.     

Luminescence of oxide ceramics in the Bi2O3-Er2O3-CeO2 system

The method of pulse high-current cathode luminescence is used to study the Bi₂O₃-Er₂O₃-CeO₂ system at room temperature in air. New luminescence centers associated presumably with cation vacancies and an anion vacancy are determined in systems containing CeO₂. The luminescence parameters are shown to behave nonmonotonically with variation of the composition of the system. It is assumed that an abrupt change in these parameters at a certain composition of the substance corresponds to a phase transformation.     

The effect of implantation of P ions on the photoluminescence of Si nanocrystals in SiO<Subscript>2</Subscript> layers

The effects of implanting 10¹³–10¹⁶ cm^?2 P ions and subsequent annealing at 600–1100°C on the photoluminescence of Si nanocrystals formed preliminarily in SiO₂ layers were studied. Quenching of the 780-nm luminescence band related to nanocrystals was observed immediately after the implantation of 10¹³ cm^?2 P ions. The recovery of emission from partially damaged nanocrystals was noticeable even after annealing at 600°C; however, heat treatments at 1000–1100°C were needed when the amorphization-threshold dose was exceeded. Intensification of luminescence was observed as a result of heat treatments of SiO₂ layers implanted with low doses of P ions; if the P content was higher than ～0.1 at. %, the recovery of luminescence was promoted. The former effect is attributed to impact crystallization of nanoprecipitates. The latter effect is attributed to the promotion of crystallization by an impurity and (along with the dose dependence of postannealing luminescence) is considered an indication that P atoms penetrate into the Si nanocrystals. Contrary to a number of estimations, introducing P does not result in the quenching of luminescence due to Auger recombination. This discrepancy is attributed to the interaction of charge carriers with the nuclei of donors.     

Deformation Processes in Mechanothermoforming Productions

It is demonstrated that in addition to the rheologic characteristics of the blank material, the deformation kinetics is determined largely by a complex operating condition, which can be varied for intentional control of the processes. The deformation processes that occur during the drawing of blanks are not simply mechanical, but thermomechanical processes that depend on the temperature conditions of the production.__________Translated from Khimicheskoe i Neftegazovoe Mashinostroenie, No. 3, pp. 6–9, March, 2005.     

UG-10K unit for the preparation of polycaproamide flake directly from the melt

Khimtekstil'mash NPO (Chernigov). Translated from Khimicheskie Volokna, No. 5, pp. 39–40, September–October, 1993.