TOF-SIMS 5 instrument sensitivity to matrix elements in GeSi Layers: Analysis based on recording of complex secondary ions

Ge _x Si_{1 − x} layers are investigated by means of secondary ion mass spectrometry (SIMS). Experimental results obtained with the use of a TOF-SIMS 5 instrument are presented. To surmount the so-called matrix effect, SIMS analysis is performed by using complex secondary ions: Ge₂⁻, CsGe⁺, and Cs₂Ge⁺.     

The effect of dynamics of sea level in southwest Baltic sea and Kattegat strait on a hydrochemical mode in deep-water horizons and fishery productivity

The features of the long-term dynamics of various indicators of a hydrochemical mode in deep-water areas of the Baltic sea were considered. Influence of the content of the dissolved oxygen and salinity of water as major ecological factors for the efficiency fishery productivity was characterized. The comparative analysis of long-term dynamics sea levels surfaces in a southwest part of the Baltic sea and in strait Kattegat was made. It was shown that inflow of water mases in many respects depended on the sea level difference between these areas from the North Sea possessing the raised salinity and the higher content of the dissolved oxygen. The principal reasons capable to lead to occurrence of the most intensive intrusion of the North Sea waters were analysed.     

Dynamical model of fission fragment angular distributions

A dynamical model of fission fragment angular distributions is developed. The experimental data on the angular anisotropy of fission fragments is analyzed for the ¹⁶O + ²⁰⁸Pb, ²³²Th, ²³⁸U, and ²⁴⁸Cm reactions at energies of the incident ¹⁶O ions ranging from 90 to 160 MeV. This analysis allows us to extract the relaxation time for the tilting mode. It was also demonstrated that the angular distributions are sensitive to the deformation dependence of the nuclear friction.

     

Nanosecond laser fluorometry of humic substances

The possibilities of laser nanosecond fluorometry in the diagnostics of humic substances (HSs) are investigated. A conclusion on the quantity of fluorophores that determine the HS fluorescence kinetics is drawn. The differences in the molecular photophysical parameters are revealed and measured for HSs of different genesises.     

Vortex structure generation on the frontal surface of a cylinder set transversely in a hypersonic flow

The problem of formation of spatially periodic structures on the frontal surface of a cylindrically blunted body set transversely in a hypersonic flow is studied. Within the framework of the model adopted, a possible mechanism of vortex structure generation on the frontal surface of the blunt body is proposed and confirmed by calculations; in this mechanism, the curved bow shock produces a vortex flow, while in its turn the vortex, which persists under weak dissipation, acts on the shock thus maintaining its curved shape. It is shown that the spatially periodic mode of hypersonic flow past a cylinder can exist in the case of a uniform incident flow and under homogeneous boundary conditions on the body surface.     

An asymmetrical periodic vortical structures and appearance of the self induced pressure gradient in the modified Taylor flow

An incompressible liquid flow in the gap between two coaxial cylinders, such that the inner rotating (wavy) cylinder has a periodically varying radius along the axial direction while the outer stationary cylinder has a constant radius, is studied experimentally and theoretically. Basic attention is focused on the symmetry-breaking phenomenon of the vortex flow arising from the rotation of the inner wavy cylinder. It is found that the symmetry-breaking phenomenon of the vortical flow structures in this geometry is accompanied by the occurrence of a self-induced axial pressure gradient. A theoretical formulation of the problem of periodic vortical flow prevailing in such a geometry having large axial length is presented. The comparison between the computed and the experimental results is presented and the underlying phenomena are discussed.     

Preparation of Ultramicroporous Materials by Fluidized-Bed Pyrolytic Deposition of Carbon in Pores of a Carbon Matrix

Samples of microporous materials were prepared by pyrolytic deposition of carbon from divinyl in a fluidized bed reactor onto carbon supports obtained from coconut and pine nut shells. The influence exerted on the adsorption capacity for CO2 by the divinyl pyrolysis temperature (in the range 600–750°С) and degree of densification (in the range 6–22%) was studied. Carbon deposition conditions ensuring the specific surface area (S_BET) lower than 5 m2 g^–1 at the adsorption capacity for СО₂ higher than 1 mmol g^–1 for both samples were found.     

An unsteady-state thermal boundary layer on a flat isothermal plate

The Kármán-Polhausen integral method is used to investigate the problem of an unsteady-state thermal boundary layer on an isothermal plate with a stepwise change in the conditions of flow around the plate; analytical expressions are obtained for the thickness of the thermal boundary layer. A dependence is found for the rate of movement of the boundary between the steady-state and unsteady-state regions of the solution on the Prandtl number. A similar problem was solved in [1, 2] for a dynamic layer, Goodman [3] discusses the more partial problem of an unsteady-state thermal boundary layer under steady-state flow conditions. Rozenshtok [4] considers the problem in an adequate statement but, unfortunately, he permitted errors of principle to enter into the writing of the system of characteristic equations; this led to absolutely invalid results. In an evaluation of the advantages and shortcomings of the integral method under consideration, given in [4], it must only be added that the method is applicable to problems in which the initial conditions differ from zero since, in this case, approximation of the velocity and temperature profiles by polynomials is not admissible.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 64–69, July–August, 1970.