Influence Of External Actions Research Articles

Influence of External Action on the Internal Structure of Continuously Cast Slab Produced from Tube Steel

The paper compares the internal structure of two continuously cast slabs with a section of 300 × 2600 mm from a tube steel of the strength class K60, one of which is molded with a soft reduction, and the other is without external influence. A comparative analysis of the structure of two templates showed that the location of areas with an increased metal pickle ness in the axial part of the templates varies. On the template from a slab cast without reduction, this section is below the geometric center of the work-piece in thickness, at a distance of 49.2% from the underside, that is, the "lower" asymmetry of the slab structure is observed. On the template from the slab cast off with soft reduction, the area with an increased pickle-ness is located above the middle of the work-piece: at a distance of 51.7% of the side of the large radius, an "upper" asymmetry of the slab structure is formed. Consequently, as a result of the external action on the cast work-piece, the location of the axial sponginess, relative to the geometric centre of the slab, is changed by moving from the lower to the upper half of the work-piece. The metal of the axial part of the reduced slab has a denser structure, the degree of development of axial looseness in the metallographic evaluation is reduced by an average of 0.5 points. The work shows the change in the content of chemical elements along the thickness of slabs. In the reduced metal, the maximum value of the degree of zonal inhomogeneity of the most impurities is higher than in the metal without external influence. This is explained by the fact that, as a result of reduction, the zone of location of the axial chemical heterogeneity in the slab becomes smaller in width.

Component analysis of the impedance of a CoFeNbSiB magnetically soft conductor with a nonuniform magnetic structure

The influence of an external magnetic field and elastic tensile stresses on the real and imaginary components of the impedance of a magnetically soft amorphous conductor with a low positive magnetostriction constant is studied. The difference is found between the frequencies at which the circular permeabilities of conductor’s parts with different types of magnetic anisotropy do not have a dominant influence on the real and imaginary components of the impedance any longer. It is shown that the sensitivity of the imaginary part of the impedance to a change in the magnetic structure of the conductor exceeds the sensitivity of the real component in a wide frequency interval. The variation of the impedance components under the influence of external actions is analyzed. This analysis may greatly expand the potential of magnetoimpedance spectroscopy, and the detection of the impedance’s imaginary component in magnetically soft and stress-impedance transducers will raise their sensitivity.

On precursor self-organization upon the microwave vacuum-plasma deposition of submonolayer carbon coatings on silicon (100) crystals

Scanning atomic-force and electron microscopies are used to study the self-organization kinetics of nanoscale domains upon the deposition of submonolayer carbon coatings on silicon (100) in the microwave plasma of low-pressure ethanol vapor. Model mechanisms of how silicon-carbon domains are formed are suggested. The mechanisms are based on Langmuir’s model of adsorption from the precursor state and modern concepts of modification of the equilibrium structure of the upper atomic layer in crystalline semiconductors under the influence of external action.

Nonauthonomous oscillations of electron beam with virtual cathode in the planar diode region

The influence of external action on the oscillations of electron beam with virtual cathode in the planar diode is investigated. The results of numerical simulations are shown for model with modulated electron beam and model with action of external signal on the virtual cathode oscillation. It is shown that system demonstrates different nonlinear oscillations, including deterministic chaos and synchronization regimes. Features of both types of external action are considered and it is shown that modulation is the most effective method of control of the virtual cathode oscillation. The investigation of physical processes in the system demonstrates appearance of complex behaviour as а result of structure interaction in the beam. Synchronization regimes are connected with suppression of structure growth. Phase correlations between external signal and virtual cathode oscillations obtained from numerical simulations and physical experiments are in the good agreement.

Influence of chemical nonequilibrium on the characteristics of power units operating on a chemically reactive gas

Flux parameter calculation features in the circuit of power units operating on a chemically-reactive N2O4 mixture are reviewed in this paper. It was observed that, contrary to chemically inert heat-transfer agents, a change in the state of a chemically-reactive gas under the influence of external action depends both on the total magnitude of the action and on its specific value. The effect of chemical reaction kinetics on the thermodynamic characteristics of similar type units has been qualitatively and quantitatively analyzed.

Influence of external action and structural factors on radiation blistering

Abstract A survey of experimental results is presented, pertaining to radiation blistering of a considerable number of materials (stainless steels, alloys with high nickel content, alloys of refractory metals) under helium ion irradiation with energies of 20–100 keV under conditions corresponding to the plasma-wall interaction: bombardment at various angles of incidence and cyclic irradiation in a wide spectrum of ion incidence angles; influence of external action, including thermocycling; influence of preceding neutron and proton irradiation. It has been shown that external factors have a complex influence on blister parameters and erosion coefficients of materials. A study has been carried out on the influence of aluminium coatings, alloying additions, phase state of material and microstructure on the nature and degree of surface erosion. Complex influence of element and phase composition, as well as microstructural changes during heat treatment and welding on radiation erosion have been established.

Opticome chanical method of studying changes taking place in the molecular structure of polymers under the influence of external actions

The results of investigations into the behavior of certain polymer films subjected to mechanical action are presented. Special attention is paid to the orientation of the molecular lattice which accompanies the deformation of the sample. As a structure-sensitive method the optical polarization technique is employed. The apparatus specially designed for the measurements in question is described. Results are given for cis-polybutadiene rubbers differing in their molecular-weight distribution and polycarbonate films differing in their degree of stretch.