Study of multigraphene films prepared by sublimation on the sic surface

Graphene films were prepared by sublimation epitaxy of SiC under vacuum. The films were studied by Auger electron spectroscopy, reflection high-energy electron diffraction, atomic force microscopy, and Raman spectroscopy. It is concluded that the films prepared are polycrystalline and consist of graphene single crystals about 50 nm in size.     

On epsilon expansions of four-loop non-planar massless propagator diagrams

We evaluate three typical four-loop non-planar massless propagator diagrams in a Taylor expansion in dimensional regularization parameter ϵ=(4−d)/2 up to transcendentality weight twelve, using a recently developed method of one of the present coauthors (R.L.). We observe only multiple zeta values in our results.     

Display of helio-geomagnetic activity in circular transformations in the troposphere

A new approach is proposed in the study of solar atmospheric effects to separate the external influence and the self-atmospheric processes. The circulation system due to external geomagnetic disturbances has been isolated. Qualitative estimates of the observed effects are given.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 39, No. 10, pp. 1335–1341, October, 1996.     

Synthesis of 4H-[1]benzopyrano[3,4-c][1,2,5]thyadiazol-4-one and its reactions with some nucleophilic and electrophilic agents

The reaction of 3,4-diaminocoumarin with thionyl chloride gave 4H-[1]benzopyrano[3,4-c][1,2,5]thiadiazol-4-one (II), which was cleaved by the action of nucleophilic agents to the corresponding 4-(2-hydroxyphenyl)-1,2,5-thiadiazole-3-carboxylic acid derivatives. The nitration of II leads to the 8-nitro or 6,8-dinitro derivative; the latter was isolated in the form of 4-(2-hydroxy-3,5-dinitrophenyl)-1,2,5-thiadiazole-3-carboxylic acid.See [3] for our preliminary communication.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 977–981, July, 1988.     

Specific features of the electronic structure of cerium and its 4d and 5d partners in CeM2 Laves phases (M=Fe, Co, Ni, Ru, Rh, Os, Pt, Mg, Al)

The x-ray line shift method has been used to study the electronic state of Ce (the 4f population) and of its 4d and 5d partners in the CeM₂ Laves phases (M=Fe, Co, Ni, Ru, Rh, Os, Pt, Mg, Al). It is shown that the valence of Ce in CeM₂ decreases monotonically from the limiting value m≈3.35 to m≈3 with decreasing intracrystalline compression of Ce atoms. The population of the outer 4d and 5d orbitals of Ru, Rh, and Os in the Laves phases has been found to be larger than that in metals. Fiz. Tverd. Tela (St. Petersburg) 40, 1397–1400 (August 1998)     

Multiple Compton effect

In this article we carry out an invariant integration of the differential cross section for the multiple Compton effect over the angular variables of the soft photons. The spectral distribution of the emitted photons is then obtained by making a transformation to the laboratory frame of reference. An estimate is made of the total cross section of the process as a function of the number of soft photons emitted.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 102–104, August, 1978.