Physics, mathematics, and technology

The special class of the threefold distributions of the projective space Pn — VH -distribution — is considered. In each center X of VH -distribution the incidence relation of the elements of the -, M-, H-subbundle has an appearance X   r  Mm  Hn1, where r  m  n  1. This class is characterized by the fact that the pairs (, ), (L, ), (M, E) of the main structural subbundles of this threefold distribution are mutual. Invariant dual normal connections induced in bundles of the 1st and 2nd kind normals of the L-subbundle of this VH -distribution are examined.

A model of distribution of concentration, velocities and temperatures of ions along a geomagnetic flux tube is considered. The model also examines the main processes of chemical kinetics, ambipolar diffusion, influence of horizontal neutral wind and plasma heating by superthermal electrons. The article presents numerical calculation results of variations of charged particles concentration in the ionosphere and the plasmasphere. The comparative analysis of various hydrodynamic approximations for the description of the ionospheric and the magnetospheric plasma is carried out. It is made on the basis of the numerical solution of the system of equations of energy, continuity and motion for O+, H+ ions and electrons along a power tube of the geomagnetic field. Differences between the hydrodynamic description and diffusive approach are especially considerable in the plasmasphere. These differences manifest themselves both in concentration of ions and in their velocities and have little impact only in distributions of temperature.

The current misalignment of the contact schedule with the actual work schedule is gradually accumulated in implementing the contact schedule of the complicated production complex. The technology of determining the characteristics of the inception and completion in the main technological operations of the electro steel melting complex is presented.

The article presents two possible approaches to controlling the movement of the exoskeleton. The first approach is the empirical determination of control actions on a person, their amplification and realization in the drives located in the hinges-joints of the exoskeleton. The essence of the second approach in the synthesis of analytical functions that provide anthropomorphic periodic movements of the exoskeleton. The novelty of the work is to take into account the change in the lengths of the links of the exoskeleton. As a numerical example, the behavior of a model with five moving links is studied. The phase images of the main motion characteristics are presented. The obtained results show significant differences between the behavior of the model in the considered approaches to controlling the movement of the exoskeleton.

Results of modeling the formation of ion shadows in a thermal ionospheric plasma consisting of oxygen ions and electrons behind a charged microsatellite are presented. The molecular dynamics method was used for modeling. It is shown that in a time of the order of 610-5 s an ionic shadow with a low ion concentration is practically formed.

-structures and almost contact structures in the tangent T-, -, L-subbundles of the regular tangently r-framed hyperstrip Hm of the n-dimensional projective space are introduced. Analytical signs and geometrical interpretations characterize the examined structures.

The article introduces the results of the research of the impedance hodographs and the capacitance-voltage characteristics of silicon photovoltaic solar energy converters based on the n+-p- junction with the antireflection coating of porous silicon on n+- region surface. The equivalent circuit of the semiconductor structure under investigation in the form of a series circuit with the constant phase elements is developed. The form of experimental capacitancevoltage characteristics is proposed.

The article considers the problem of the use of analog-to-digital and digital- to-analog converter (ADC-DAC) at practical physics lessons in a college. The authors analyze prepared laboratory class materials in Physics, based on reasonably priced Russian-manufactured «ZET-210» DAC-ADC module. Bundled ZETLAB software enables to turn a computer into a physics minilaboratory, which allows to generate, measure, analyze signals, and visualize measurements. The article demonstrates sure advantages of the use of DACADC technology base at practical physics lessons at college. This technology is compared with traditional lessons equipment, when unconnected laboratory setups are constructed for research of each effect and phenomenon.

A velocity model of internal friction is considered. It is shown that the use of a linear velocity model of internal friction makes it possible to describe the results of published experimental studies of longitudinal damped oscillations of cargo on a short cable.