Negative refraction in natural ferromagnetic metals

It is generally believed that Veselago's criterion for negative refraction cannot be fulfilled in natural materials. However, considering imaginary parts of the permittivity ({\epsilon}) and permeability ({\mu}) and for metals at not too high frequencies the general condition for negative refraction becomes extremely simple: Re({\mu}) Re(n) < 0. Here we demonstrate experimentally that in such natural metals as pure Co and FeCo alloy the negative values of the refractive index are achieved close to the frequency of the ferromagnetic resonance. Large values of the negative refraction can be obtained at room temperature and they can easily be tuned in moderate magnetic fields

Evolution of theoretical approaches to the competitiveness conception

The main approaches to the analysis of competition and competitiveness of the companies have been studied; the authorship approach has been proposed, and the specific features and the main components of it were described. To analyze the specific features of competitiveness theories the main periods of evolutionary development of the economic thought were identified with regard to the competitiveness of the entities of economic activities; the main factors of competitiveness of the companies during different periods of the evolution of economic thought were specified

Analysis of Structure Destroyed Metal after Diffusion Heat Treatment

It was accomplished research of the structure steel which carbonitriding and subsequent heat treatment was exposed for its cause's destruction to discover. For measure quality field of metal were used methods optical, appearing electronic microscopy and X-ray diffraction. Therefore one of the principal problems were research phase composition, grain and dislocation structure of a metal the gear teeth. Mechanism of rising hear cracks in the gear teeth on different stages her making and their trajectories of evolution were determined

Modeling of the Process of Welding Aerosol Formation Taking Place During Mining Equipment Fabrication

In the paper the authors formulate the thermodynamic model of welding aerosol formation. The thermodynamic parameters of chemical compounds and aerosol phases are calculated. The authors develop a program for numerical calculation of various elements emission under varied parameters changing the welding conditions

Russian Approaches to the Forest Type Classification

The results of researches characterizing the geographical distribution of forest-ecological, phytocoenotic, and genetic classifications of forest types in the Russian Federation nowadays are presented in the thesis. A comparative analysis was carried out for the following items: the inclusive concept of a classification unit (a type of habitat conditions; a type of forest); features of distinguishing the border of the classification units; classification features used to determine the type of habitat conditions; features of the classification of phytocoenoses used to determine the forest type; the degree to which the successional dynamics of forest stands are taken into consideration; the degree to which the influence of anthropogenic factors are taken into consideration; the level of implementation in forest management and forestry practice; regions of implementation. In the process of development of forest typologies, the concept of a forest type changed from understanding it as a forest area homogeneous by composition, structure, and appearance (homogeneity in space) in natural classifications to the concepts of a forest type, in which priority is given to homogeneity in origin (genesis), as well as developmental processes and dynamics (homogeneity in time) in genetic and dynamic typologies. Currently, there is the following forest type classification in the Russian Federation: forest-ecological, phytocoenotic, genetic, and dynamic. When classifying forest areas within the forest-ecological direction provided by E.V. Alekseev - P.S. Pogrebnyak, the priority is given to the characteristics of the habitat conditions. Within the phytocoenotic direction provided by V.N. Sukachev, the priority is given to the phytocoenosis characteristics. Within the genetic approach provided by B.A. Ivashkevich - B.P. Kolesnikov, a forest type is considered as a series of alternating phases - types of phytocoenosis within the same type of habitat conditions. In this case, phytocoenotic classifications can be a part of the genetic classifications for the climax forest phytocoenosis. And the dynamic approach provided by I.S. Melekhov is very close to the genetic one and is a superstructure over the classical phytocoenotic forest typology provided by V.N. Sukachev. The current use of forest typological classifications by forest inventory management enterprises in the Russian Federation was studied. A map of the geographical distribution of forest typologies of the above-listed directions of forest typology researches was created. Forest-ecological classifications are used mainly in the southern regions of the European part of Russia and the North Caucasus. Forest typologies created based on a genetic approach to the forest type classification are used in Western Siberia, in the south of the Far East and Eastern Siberia, and in some regions of the Urals. Phytocoenotic classifications of forest types are used in other regions of the Russian Federation. © Published under licence by IOP Publishing Ltd.The study was carried out with the financial support of the Russian Foundation for Basic Research as part of the scientific project No. 20-14-50422 and a state assignment supported by the Ministry of Science and Higher Education of the Russian Federation (project FEUG-2020-0013)

Kinetic parameters of the uranium luminescence in Lif crystals

The results of researches with nanosecond time resolution of kinetic characteristics of luminescence buildup and decay in crystals LiF(U)-O at 300 K under action of both laser pulse with energy 3,68 eV and electron pulse with energy 300 keV have been presented. Influence of excite method on kinetic characteristics of uranium luminescence buildup and influence of uranium on kinetic characteristics of oxygen luminescence in crystal were establishe

Optimization of Higher Alkanes Dehydrogenation Process under Conditions of Decreased Hydrogen Containing Gas Flow with Using Mathematical Modeling

The article proposes the way of saving catalyst resource and increasing the efficiency of higher alkanes dehydrogenation process using mathematical model method. The study has indicated, that reducing hydrogen/feedstock molar ratio results in balance shear of alkanes dehydrogenation reaction to alkenes, which is proved by the results of pilot operating of the alkenes production unit at Ltd. KINEF and by the mathematical model calculations. The results of the prediction calculation of optimum process parameters at various hydrogen/feedstock molar ratios are presented

Brittle fracture strength analysis for reactor pressure vessel of VVER-1000 reactor unit

At the moment, 11 nuclear power plants (NPP) are under operation in the Russian Federation. More than half of the reactor units used are VVER-1000 reactors. NPP is a complex engineering structure consisting of plenty of complex equipment. Equipment operates under severe conditions: hard radiation, high temperatures, and high pressure. Nuclear reactor has a finite lifespan of 30 years. Most nuclear power plants based on VVER-1000 reactors have almost exhausted their lifespan. Therefore, these reactors require a life extension analysis. This paper demonstrates an analysis of brittle fracture strength for VVER-1000 reactor pressure vessel. According to the findings, calculated parameters do not outreach the 10 % limit