Volume properties of reverse micellar systems AOT/n-heptane/DMSO-water

The volume properties of reverse micellar systems bis(2-ethylhexyl) sulfosuccinate sodium salt/n-heptane/dimethyl sulfoxide-water are studied via densitometry. The presence of dimethyl sulfoxide and the increase in its amount in a dimethyl sulfoxide-water mixed solvent raise the apparent volume of the polar phase. This increase is also observed when the degree of hydration of the polar core and the temperature are raised.     

Cherenkov-transition radiation in gamma frequency region

The spectral and angular distributions, as well as the total number of photons of gammaray Cherenkov-transition radiation (GCTR) produced by charged particles in the photon energy region (0.8–2) MeV, are calculated using the results of the recent discovery that in the above-mentioned region the refraction index of some materials is greater than unity, n(ω) > 1, due to Delbruck scattering on Coulomb field of nuclei. Using the results of the numerical calculations carried out, we propose an experimental arrangement for observation and study of GCTR produced by electrons with energy much higher than the threshold energy of GCTR (～10 GeV). Some applications of GCTR, in particular, the search for new materials with n(ω) > 1 in gamma region with the help of this method, are discussed.     

Erratum to: Natural Vibrations of Micropolar Elastic Flexible Plates and Shallow Shells

Acoustical Physics - An Erratum to this paper has been published: https://doi.org/10.1134/S1063771022340012     

Doppler-free satellites of resonances of electromagnetically induced transparency and absorption on the D 2 lines of alkali metals

The peculiarities of intra-Doppler structures that are observed in the atomic absorption spectrum of alkali metals with the help of two independent lasers have been studied. These structures accompany ultranarrow coherent resonances of electromagnetically induced transparency and absorption. With the D ₂ line of rubidium taken as an example, it is shown that, in the scheme of unidirectional waves, the maximum number of satellite resonances caused by optical pumping selective with respect to the atomic velocity is equal to seven, while only six resonances are observed in the traditional scheme of saturated absorption with counterpropagating waves of the same frequency. The spectral position of the resonances and their polarity depend on the frequency of the saturating radiation, while their number and relative amplitude depend also on the experimental geometry. These features are of general character and should show themselves in the absorption spectrum on the D ₂ lines of all alkali metals. An explanation of these features is given. The calculated spectral separations between the resonances are compared to the experimental ones, and their possible application is discussed.     

A study of dark resonance splitting for the D 1 line of 87Rb in strong magnetic fields

The process of electromagnetically induced transparency (EIT) is studied using an extremely thin cell with thickness of a vapor column of rubidium atoms L = 794 nm. Wavelengths of resonant laser beams ?? ?? 794 nm. Results of the study of behavior of the EIT resonance (which is also called the ??dark?? resonance) formed in the ?? system of the D ₁ line of ⁸⁷Rb atoms in strong magnetic fields up to 1700 G (0.17 T) are reported for the first time. Three dark resonances are recorded in magnetic fields with induction B < 300 G, two resonances are recorded at B > 650 G, and only one dark resonance is retained at B > 1200 G. A method of the formation of a dark resonance at a given frequency is demonstrated that will allow, under the corresponding conditions, the formation of a dark resonance also at B > 0.2 T. The experimental results are well described by the known theoretical models. Practical applications of these results are indicated.     

Synthesis of derivatives of 4,5-dihydrofuran,furan, and hexahydrobenzofuran from conjugated alkenynes

The regiochemistry of the reaction of 1,2- and 1-substituted derivatives of 1-buten-3-yne and its 4- and 2,4-substituted derivatives of the isoprenoid type with acetoacetic ester and acetylacetone in the presence of the manganese(III) acetate-copper(II) acetate oxidative system was studied. Derivatives of 4,5-dihydrofuran, furan, and hexahydrobenzofuran were obtained.Communication 137 from the series Reactions of unsaturated compounds. See [1] for communication 136.Translated from Khimiya Geterotsiklicheskikh Soedinenii, Vol. 24, No. 3, pp. 317–323, March, 1988.     

The Properties of Mixtures of Sodium Dodecylsulfate and Diethylsulfoxide in Water

The aqueous mixtures of sodium dodecylsulfate (SDS) and diethylsulfoxide (DESO) have been studied using conductivity, viscosity and surface tension techniques. The critical micellar concentration (cmc) was determined in the presence of DESO at 30, 40, and 50 C from conductance and surface tension measurements. The enthalpy ( G_m), entropy ( S_m) and Gibbs energy ( G_m) of micellization were determined from the temperature dependence of the cmc. The results obtained were compared with published results for aqueous solutions of SDS and dimethylsulfoxide (DMSO). The data demonstrate a more pronounced inhibitory effect of DESO on the micellization of SDS, in comparison with the effect of DMSO. On the basis of the dependences of the relative viscosities on concentration, as given by the Jones–Dole semi-empirical equation, the B-coefficients have been calculated for the post-micelle composition region.