Transformation of 1,1,3,3-tetramethyl-1,3-disilacyclobutane in presence of aluminum chloride

Conclusions The reaction of equimolar amounts of 1,1,3,3-tetramethyl-1,3-disilacyclobutane and aluminum chloride gives tetramethylsilane and a mixture of linear and cyclic silmethylene compounds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 953–955, April, 1975.     

Reaction gas chromatography-mass spectrometry. Communication 5. Determination of the position of the double bond in alkenes using selective deuteration in the column of a gas chromatograph-mass seectrometer

Conclusions A method was proposed for determining the position of the double bond in alkenes based on the comparative analysis of the mass spectra of the corresponding alkanes and vicinal dideuteroalkanes, obtained directly during the hydrogenation and selective deuteration of the alkenes in a specially developed reaction column.Cf. [1] for Communication 4.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya., No. 3, pp. 581–584, March, 1985.     

Technology of polishing of titanium surface using the fiber-laser radiation

The effect of the radiation of the pulsed fiber laser on the surfaces of cylindrical samples made of the VT16 titanium alloy is studied. It is demonstrated that the irradiation at appropriate parameters of the laser radiation in the inert-gas (argon) atmosphere leads to an increase in the microhardness of the surface layer and a decrease in the surface roughness of the irradiated samples by a factor of five in comparison with the roughness of the original samples.     

Carter subgroups and Fitting heights of finite groups

Let G be a finite group possessing a Carter subgroup K. Denote by \(\mathbf {h}(G)\) the Fitting height of G, by \(\mathbf {h}^*(G)\) the generalized Fitting height of G, and by \(\ell (K)\) the number of composition factors of K, that is, the number of prime divisors of the order of K with multiplicities. In 1969, E. C. Dade proved that if G is solvable, then \(\mathbf {h}(G)\) is bounded in terms of \(\ell (K)\). In this paper, we show that \(\mathbf {h}^*(G)\) is bounded in terms of \(\ell (K)\) as well.     

Selective spectroscopy of tunneling transitions between the Landau levels in vertical double-gate graphene–boron nitride–graphene heterostructures

The spectral and total electron densities of states in two-dimensional FeAs clusters, which simulate iron-based superconductors, have been calculated using the generalized quantum Monte Carlo algorithm within the full two-orbital model. Spectra have been reconstructed by solving the integral equation relating the Matsubara Green’s function and spectral density by the method combining the gradient descent and Monte Carlo algorithms. The calculations have been performed for clusters with dimensions up to 10 × 10 FeAs cells. The profiles of the Fermi surface for the entire Brillouin zone have been presented in the quasiparticle approximation. Data for the total density of states near the Fermi level have been obtained. The effect of the interaction parameter, size of the cluster, and temperature on the spectrum of excitations has been studied.     

The Skyrme-TQRPA calculations of electron capture on hot nuclei in pre-supernova environment

We combine the thermal QRPA approach with the Skyrme energy density functional theory (Skyrme–TQRPA) for modelling the process of electron capture on nuclei in supernova environment. For a sample nucleus, ⁵⁶Fe, the Skyrme–TQRPA approach is applied to analyze thermal effects on the strength function of GT₊ transitions which dominate electron capture at E _e ≤ 30 MeV. Several Skyrme interactions are used in order to verify the sensitivity of the obtained results to the Skyrme force parameters. Finite-temperature cross sections are calculated and the results are comparedwith those of the other model calculations.     

Combined MEIS/TEM study of structural defects in Si implanted with a high dose of 100 keV Si ions

Medium-energy ion scattering and transmission electron microscopy have been used to study the structural perfection of a Si single crystal implanted with 100 keV Si ions at a dose of 1×10¹⁷ cm^?2, which exceeds the amorphization threshold by two orders of magnitude. The implantation of Si ions was found to produce a high density of extended defects without amorphization of the Si layer. The increasing depth dependence of the full width at half-minimum of the dip in angular scans of backscattered protons, was observed in a Si layer containing a high density of extended defects, in contrast to the decreasing dependence in the perfect Si crystal.     

Structure and ultraviolet photoluminescence of 3C-SiC films grown on Si(111)

The structure and light-emitting properties of nanocrystalline cubic silicon carbide films prepared by chemical conversion from hexane vapors are discussed. The morphology, the composition, and the crystallographic structure of the grown silicon carbide thick films are thoroughly analyzed using X-ray diffraction, electron diffraction, white light interferometry, and scanning probe and transmission electron microscopies. The excitation with the use of the third harmonic of a femtosecond laser (λ_excit = 266 nm) makes it possible for the first time to reveal the luminescence line lying in the deep UV region with the wavelength λ = 340 nm in addition to the usually observed lines in the high-temperature photoluminescence spectrum. The nature of the lines observed in the photoluminescence spectrum is discussed.     

Thermal effects on electron capture for neutron-rich nuclei

Thermal effects on allowed and first-forbidden proton-neutron transitions in neutron-rich nuclei are studied with the formalism of the thermofield dynamics. The p → n transition strength distributions as well as an electron capture cross section for the parent nucleus ⁷⁶Ge are calculated at different temperatures with the Hamiltonian of the quasiparticle-phonon nuclear model. Original Russian Text ? A.A. Dzhioev, A.I. Vdovin, V.Yu. Ponomarev, J. Wambach, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No. 2, pp. 236–240.