Calculation of specific heat of germanium by five force schemes

The specific heat and dispersion frequencies of germanium are calculated for five force schemes, making allowance for the interaction between neighbors in the crystal lattice, up to second neighbors, for which all interaction coefficients are expressed in terms of experimentally determined elastic constants and the cutoff frequencies of the optical branches.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 57–62, May, 1977.     

Efficiency of Using an Analyzed Substance in Arc and Spark Light Sources

In order to evaluate the efficiency of application of an analyzed substance in electrode light sources for spectral analysis, it is suggested to use the ratio between the intensity of the concentrationsensitive spectral line of a chemical element and the product of the mass of the substance brought from the sample during exposure and the energy of a single pulse of a light source. It is established that annealing and sparking may favor stable selective entry of a substance into a plasma.     

Post‐Synthesis Stabilization of Germanosilicate Zeolites ITH,IWW, and UTL by Substitution of Ge for Al

Germanosilicate zeolites often suffer from low hydrothermal stability due to the high content of Ge. Herein, we investigated the post‐synthesis introduction of Al accompanied by stabilization of selected germanosilicates by degermanation/alumination treatments. The influence of chemical composition and topology of parent germanosilicate zeolites ( ITH , IWW , and UTL ) on the post‐synthesis incorporation of Al was studied. Alumination of ITH (Si/Ge=2–13) and IWW (Si/Ge=3–7) zeolites resulted in the partial substitution of Ge for Al (up to 80 %), which was enhanced with a decrease of Ge content in the parent zeolite. In contrast, in extra‐large pore zeolite UTL (Si/Ge=4–6) the hydrolysis of the interlayer Ge?O bonds dominated over substitution. The stabilization of zeolite UTL was achieved using a novel two‐step degermanation/alumination procedure by the partial post‐synthesis substitution of Ge for Si followed by alumination. This new method of stabilization and incorporation of strong acid sites may extend the utilization of germanosilicate zeolites, which has been until now been limited.     

Influence of modifying cobalt(II) chloride additive on the selectivity of stationary phases in gas chromatography

Effect of a modifying cobalt(II) chloride additive on the selectivity of adsorbents and liquid stationary phases used in gas chromatography for the separation of volatile organic substances (VOSs) of different chemical nature is considered. It is found that the specified additive leads to a drastic increase in the retention parameters of oxygen-containing VOSs, first of all, aliphatic alcohols, and relatively weakly affects the retention of other VOSs, including nucleophilic nitrogen-containing compounds. In particular, the addition of cobalt chloride to Carbowax increases the retention parameters of methanol and ethanol and reduces the corresponding parameters for analytes from the other VOS classes.     

Numerical study of the exact solution of the Navier–Stokes equations describing free-boundary fluid flow

This paper presents a numerical study of the partially invariant solution of the Navier–Stokes equations for the plane case which describes unsteady flow in a layer bounded by a straight solid wall and a free boundary parallel to it. It is found that for different initial flow velocities, a steady state can be established with a decrease or an increase in the initial layer thickness or the layer thickness can be increased infinitely due to fluid inflow from infinity.