Electronic origin of the incommensurate modulation in the structure of phosphorus IV

An incommensurate modulated structure was found recently in a light group V element phosphorous in the phase P-IV stable in the pressure range 107-137 GPa. We consider configurations of the Brillouin zone and Fermi sphere within a nearly-free-electron model in order to analyze the importance of these configurations for the crystal structure energy. For the phase P-IV with the base-centered orthorhombic structure, oC2, we consider a commensurate approximant with an 11-fold supercell along the c-axis and a modulation wave vector equal 3/11 which is close to the experimentally observed value of 0.267. Atomic shifts due to the modulation result in appearance of satellite reflections and hence in a formation of additional Brillouin zone planes. The stability of this structure is attributed to the lowering of the electronic band structure energy due to Brillouin zone - Fermi surface interactions

Transformations of Phosphorus under Pressure from Simple Cubic to Simple Hexagonal Structures via Incommensurately Modulations: Electronic Origin

The lighter group-V element phosphorus forms the As-type (hR2) structure under pressure, above 5 GPa, and at 10 GPa transforms to the simple cubic structure (cP1), similar to arsenic. Despite of its low packing density, the simple cubic structure is stable in phosphorus over a very wide pressure range up to 103 GPa. On further pressure increase, the simple cubic structure transforms to a simple hexagonal structure (hP1) via a complex phase that was solved recently as incommensurately modulated. Structural transformations of phosphorus are connected with the changes of physical properties. Above 5 GPa phosphorus shows superconductivity with Tc reaching ~9.5K at 32GPa. The crystal structures and properties of high-pressure phases for phosphorus are discussed within the model of the Fermi sphere and Brillouin zone interactions.Comment: 6 page, 6 figures, the 1st International Electronic Conference on Crystals 21-31 May 2018. arXiv admin note: substantial text overlap with arXiv:0911.240

Structure stability in the simple element sodium under pressure

The simple alkali metal Na, that crystallizes in a body-centred cubic structure at ambient pressure, exhibits a wealth of complex phases at extreme conditions as found by experimental studies. The analysis of the mechanism of stabilization of some of these phases, namely, the low-temperature Sm-type phase and the high-pressure cI16 and oP8 phases, shows that they satisfy the criteria for the Hume-Rothery mechanism. These phases appear to be stabilized due to a formation of numerous planes in a Brillouin-Jones zone in the vicinity of the Fermi sphere of Na, which leads to the reduction of the overall electronic energy. For the oP8 phase, this mechanism seems to be working if one assumes that Na becomes divalent metal at this density. The oP8 phase of Na is analysed in comparison with the MnP-type oP8 phases known in binary compounds, as well as in relation to the hP4 structure of the NiAs-type

Regional population expenditure for foodstuffs in the Russian Federation: componential and cluster analyses

The article describes the solving of the problem of conducting the component and cluster analyses of population expenditure on food as one of the most important components of the standard of living. The purpose of the analysis is to develop the regional clusters of the Russian Federation, which vary in the structure of household expenditure for foodstuffs. The foodstuffs are presented in absolute units taking into integral account the standard of living index. The methods of intellectual analysis such as component and cluster analyses are applied as the research methods. The procedure for the data intellectual analysis based on the interconnected performance of component and cluster analyses is proposed. The procedure of the data intellectual analysis considers the interrelation between the results received by different methods, and also the possibility to return to the previous method for the purpose of repeating the analysis to specify consistently the clusters composition. Few clusters of the wealthy regions characterized by the high and average levels of expenditure for foodstuffs are revealed as well as the quite many clusters of not enough wealthy and not wealthy regions characterized by the low level of expenditure for foodstuffs. It is shown that the growth of standard of living characterized by the size of a gross regional product per capita is followed by the growth of the Gini coefficient, which indicates both the inequality of income distribution and reduction in expenditure for low-value foodstuffs. The results of the analysis can be applied to the development of the decision-making support system intended for the analysis of the scenarios of macroeconomic regulation in the eld of income policy for the purpose of increasing the standard of living of population. The analysis of the population expenditure for foodstuffs has allowed to reveal the cluster structure of the regions of the Russian Federation, to show it according to the generalized indications, to formulate the specific characteristics of the clusters of the regions and important management decisions

Numerical Simulations of Solid and Slotted Cold-Formed Steel Channels with Different Boundary Conditions in Shear

This paper presents results of a numerical study on the shear strength of cold-formed steel channels with solid and slotted webs. The effects of four different boundary conditions—test setup, realistic, and simply supported with free and restrained ends—on the elastic shear buckling load and the ultimate shear strength were considered. The study was performed on finite element models developed in ANSYS and validated against test data. The obtained results showed that the elastic shear buckling loads and the ultimate shear strengths of the slotted channels are more sensitive to the boundary conditions when compared with the solid channels. The simply supported boundary conditions can reasonably well simulate the test setup boundary conditions of the solid channels but not the slotted channels. The realistic boundary conditions cannot be accurately simulated by the simply supported boundary conditions for the solid and slotted channels

Analysis of the innovation and investment state in the sphere of industrial production of the Russian Federation

The article presents an analysis of the innovative and investment state in the industrial production in the Russian Federation. The indicators “production and sales” of the Russian Federation, USA, Germany and Brazil are compared. An analysis of the Global Innovation Index and its components, in the context of seven indicators in the countries under study, is presented. Russia’s place in the IMD World digital competitiveness rating, is analysed. The main methods used in the study are analysis and generalisation, and the construction of chain indices based on statistical information on industrial indicators, the Global Innovation Index and the level of assessment of the digital competitiveness of four countries. Conclusions are drawn about the impact of the studied indicators on the economy and, at the moment, the Russia’s position is not entirely positive according to these indicators. It is proposed, to include these indicators in the methodology for managing corporate innovations and investments in industry under digitalisation to improve the economic level of the country as a whole

Providing incentives for the microelectronics industry as a part of achieving technological sovereignty

The Government of the Russian Federation is implementing comprehensive measures to counter sanctions, stabilize the economy, restore economic security, and achieve technological sovereignty. Draft laws to close lacunas are being considered, and measures taken to support domestic enterprises in the sphere of economic development priority areas. It is impossible to universally finance a wide range of projects, so the author of the article recognizes expediency of considering prioritization according to certain criteria, such as size of the industry, participation in value chains, efficiency, and operability of the industry at the moment. For the microelectronics industry, it is important to consider state of inter-industry balance indicators to generate orders and maintain economic equilibrium, as its manufactured products are consumed in almost all sectors of the economy due to digitalization penetration at different levels. The purpose of the study is to identify trends in global economy, analyze and predict actions of major players, analyze the Russian microelectronics industry, and rationalize suggestions based on the data collected. The suggestions are to create conditions for innovative development institutions interaction with groups of educational institutions in order to realize joint projects to create innovations. The methodological basis for building the model was provided by modern works in the researched area. The article considers main causes and problems preventing industries from getting out of the critical state within the framework of achieving technological sovereignty, analyzes current state of the microelectronics industry in the current geopolitical situation, and proposes external and internal ways to expand the ‘bottlenecks” in the form of measures to stimulate end-to-end technologies creation