Isomer conversions in perfluoro-1-ethylindane under the action of antimony pentafluoride

Perfluoro-1-ethylindane on heating with SbF₅ is isomerized to perfluoro-1,1-dimethylindane, perfluoro-,-o-trimethylstyrene, and perfluoro-1,2-dimethylindane. In the presence of SbF₅, the latter two products are converted one into the other. In addition, in SbF₅ perfluoro-1,2-dimethylindane is defluorinated to perfluoro-2,3-dimethylindene and fluorinated to perfluoro-2,3-dimethyl-4,5,6,7-tetrahydroindene which is further fluorinated to perfluoro-1,2-dimethyl-4,5,6,7-tetrahydroindane and is converted at 200C to perfluoro-1,7-dimethylindane. The latter is also formed on heating perfluoro-,-o-trimethylstyrene with SbF₅ at 200C.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 645–652, March, 1990.     

Inhibitory Effect of 2-Aminothiazole Derivatives in Oxidation Reactions

The kinetics and mechanism of inhibitory effect of 2-aminothiazole derivatives in the radical-initiated oxidation of cumene were studied.     

Sorption of sodium dodecyl sulfate by highly basic anion-exchange resins

The interaction in the system of sodium dodecyl sulfate (SDS) solution and AB-17 highly basic anion-exchange resins in OH⁻ and Cl⁻ forms were considered, and the distribution coefficients (K _d) of the substance in the resin-solution ion exchange system were calculated. It was found that K _d decreases with increasing concentration of the initial solution, reaching a maximum value at the critical micelle concentration (CMC) of SDS. The effective diffusion coefficients of the surfactant in the anion-exchange resin phase were calculated; based on the IR spectroscopy data, the mechanism of SDS absorption was proposed.     

Effect of Alizarin Red S on the formation of hydroxyapatite crystals

Hydroxyapatite samples were prepared in systems calcium nitrate-diammonium hydrogen phosphate-ammonium hydroxide-organic component with addition of microamounts of Alizarin Red S. The participation of sulfo and hydroxy groups of the organic compounds in the formation of hydroxyapatite crystals was confirmed by X-ray phase analysis, IR spectroscopy, electron microscopy, and elemental analysis.     

Appearance of polar optical modes in raman scattering in semiconductor nanocrystals

The Raman spectra of nine samples of glasses with different content of CdSe semiconductor nanocrystals of different dimensions obtained by annealing samples are studied. It is established that, in the spectra of nanocrystals of all samples, there appears a line of the fundamental polar vibration whose frequency is close to that of the longitudinal optical mode of the CdSe bulk crystal. In this case, the asymmetry of this line essentially depends on the sample, the semiconductor concentration, and the local excitation place. To analyze the obtained results, a factor analysis method is used to separate linearly independent components from the data set. It is established that three or four contributions with frequencies near 180, 190, 208, and, probably, 210 cm^?1 can be singled out in the contour of the line under consideration. A comparison of the obtained results with the conclusions made by using microscopic models demonstrates a significant difference between the experimental data and the results obtained by using mechanical and dielectrical continuum models. It is possible that the real picture of quantum dot vibrations is more complicated and can be described better within the microscopic model. Moreover, for a CdS nanocrystal, the experimental spectra agree satisfactorily with results of calculation of vibrations, in which 3–4 bands with a frequency difference of 10-15 cm^?1 exist in the region of the LO mode for crystals with dimensions of 5 × 5 × 5 unit cells (1000 atoms).     

Rotation number quantization effect

We study a class of dynamical systems on a torus that includes dynamical systems modeling the dynamics of the Josephson transition. For systems in this class, we introduce certain characteristics including a sequence of functions depending on the system parameters. We prove that if this sequence converges at a given point in the parameter space, then its limit is equal to the classical rotation number, and we then call this point a quantization point for the rotation number. We prove that the rotation number of such a system takes only integer values at a quantization point. Quantization areas are thus defined in the parameter space, and the problem of effectively describing them becomes an important part of characterizing the systems under study. We present graphs of the rotation number at quantization points and under conditions when it is not quantized (an example of a half-integer rotation number) and diagrams for quantization areas.     

Computer model of a meteor radio channel

A computer model of a meteor radio channel is presented. The model is based on the Monte-Carlo method. The possibility of effective choice of the model parameters is proved. The simulation results agree well with the experimental data obtained in meteor radio lines with lengths of 240, 700, and 1100 km.State University, Kazan. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 38, No. 11, pp. 1177–1186, November, 1995.