New Chiral Ortho-P,S-Difunctionalized Aromatic Compounds

Abstract

A new method to prepare enantioenriched sulfinates was developed to obtain optically active ortho-methylsulfinyl(phenylphosphonates). It consists of a diastereoselective oxidation of sulfenates to sulfinates. Additionally, preliminary results concerning the synthesis of ortho-phophonylated benzylic thiol derivatives via a new P═S to P═C [1,4]-rearrangement and a first synthetic application of these compounds are also described.     

Studying characteristics of the large-scale ionospheric irregularities induced by high-power HF radio emission with GPS diagnosis

We present the results of experimental studies of artificial large-scale irregularities of the ionospheric electron number density with dual-frequency GPS diagnosis. The total electron content was analyzed in the GPS signal trajectory when the satellites passed over the heated region. Spectral composition of the observed variations was determined by wavelet analysis. Characteristic scales of artificial irregularities of the electron number density in the F layer are estimated. It is experimentally proved that the irregularities remain for at least 15–20 min after the transmitter is switched off. A more confident excitation and increased intensity of the irregularities were also confirmed when the beam was inclined south of the magnetic-zenith direction.     

Influence of small-scale irregularities on the features of the overshoot effect in the temporal evolution of stimulated electromagnetic emission. Part I. Development stage

We present the results of experimental studies of the evolution of stimulated electromagnetic emission of the ionosphere (SEE) under the F-layer modification by powerful HF radio waves in a broad range of the pump wave frequencies. We compare the parameters of the overshoot effect in SEE evolution to the observations of anomalous attenuation and field-aligned scattering of radio waves. We show the overshoot effect to result from the anomalous attenuation under scattering at artificial small-scale ionospheric irregularities. We found the characteristic time scales of the overshoot effect development to decrease and its value to increase as the pump wave frequency decreases from 6 to 4 MHz; this is attributed to the observed increase of the irregularities amplitude at scales m. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 7, pp. 619–634, July 1999.     

On the theory of anomalous absorption of an ordinary wave

We obtain and analyze numerically exact formulas for anomalous absorption of a probing ordinary wave due to its transformation into plasma waves under vertical sounding of an ionospheric plasma layer with given spectrum of irregularities. The nature of possible approximations and their validity limits are analyzed. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 42, No. 8, pp. 826–836, August 1999.     

The effect of temperature on carrier transport in molecularly doped polycarbonate

The effect of elevated temperature on the pattern of current transients and the hole mobility in polycarbonate doped with 20 and 30 wt % aromatic hydrazone was studied. With the use of homogeneous carrier generation mode, it was found that the shape of the current transient varies with an increase in the temperature in qualitative agreement with the prediction of the multiple-trapping theory with the exponential trap energy distribution. The apparent activation energy of hole mobility is 0.41 eV in the classical measurement mode and 0.55 eV in the case of homogeneous irradiation.