Transfer and Trapping of Resonance Radiation in a Two-Level System

Optics and Spectroscopy - The population kinetics of a two-level system has been theoretically investigated taking into account the transfer of spontaneous radiation under continuous optical...     

New methods for determining the volumetric flow rate in the column and the retention time of the unretained substance in gas chromatography

New methods for calculating the mean volumetric flow rate of the carrier gas and the retention time of the unretained substance in the column under conditions of gas chromatography were proposed. The methods are based on preliminary isothermal calibrations of the flow rate and holdup time for a packed column. A theoretical substantiation of the methods was given. Procedures of plotting calibration dependences for determining the indicated quantities at a desired temperature were described. The calculation results were compared to experimental data obtained by traditional methods. It was demonstrated that the use of calculation methods substantially simplifies the determination of the specific retention volume over a wide temperature range.     

Power expansions for the self-similar solutions of the modified Sawada-Kotera equation

The fourth-order ordinary differential equation that defines the self-similar solutions of the Kaup—Kupershmidt and Sawada—Kotera equations is studied. This equation belongs to the class of fourth-order analogues of the Painlevé equations. All the power and non-power asymptotic forms and expansions near points z = 0, z = ∞ and near an arbitrary point z = z ₀ are found by means of power geometry methods. The exponential additions to the solutions of the studied equation are also determined.      

Properties of nonlinear waves in dissipative-dispersive media with instability

Wave processes in dissipative-dispersive media with instability described by a fourth-order nonlinear evolution equation are considered. Analytic solutions in the form of solitary and cnoidal waves are obtained. The existence of a critical value of the dispersion coefficient beyond which an initial disturbance (in particular, white noise) is transformed into a structure is demonstrated by numerical modeling.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 130–136, July–August, 1990.     

The adsorption of organic compounds on a modified carbon adsorbent Carbopack B

The thermodynamic characteristics of adsorption of several organic compounds on the carbon adsorbent Carbopack B before and after its modification by a monomolecular layer of cholesteryl-n-pentyl oxybenzoate were determined by gas chromatography. The initial adsorbent was close in its properties to graphitized carbon black. Modification weakened adsorbate-adsorbent attraction and increased the mobility of adsorbed molecules, to a greater extent for nonpolar adsorbents and to a lesser extent for compounds capable of specifically interacting with modifier molecules.     

Analysis of Mixtures Containing Unknown Components by Gas Chromatography: Determination of Molecular Mass

New methods are proposed for the gas-chromatographic determination of the molecular masses of unknown components in complex mixtures within one cycle of analysis. The methods are based on the use of complex chromatographic data in the form of linear retention indices of compounds for a column with a nonpolar stationary phase and sensitivity indices of a thermal conductivity detector and a flame ionization detector.     

Effect of the polyoxoanion of phosphotungstic acid on the photoconversion efficiency of dye-sensitized solar cells based on titanium dioxide

A method for fabricating form composite photoanodes based on titanium dioxide and phosphotungstic acid has been developed. The introduction of the polyoxometalate into a porous titanium dioxide layer increases the photoconversion efficiency of dye-sensitized solar cells and affects characteristics such as open-circuit voltage and short-circuit current.     

Localized growth of materials from amorphous hydrogenated carbon by barrier-discharge treatment of benzene vapor-argon mixture

The possibility of a localized growth of materials from amorphous hydrogenated carbon by the barrier-discharge treatment of a benzene vapor mixture with argon has been shown. Two types of material are produced, the “columnar” black entities of ～100 μm in diameter and 2 mm in height and the “polymeric patterns” as “honeycombs” of ～ 4–6 mm diameter with a clearly defined boundary in the form of the “swell” as high as 100 μm. The structure and composition of the materials and their growth kinetics have been investigated.