Skewed Sudakov Regime at One Loop Kim, V. T.; Pivovarov, G. B.
Physics of particles and nuclei letters,
09/2019, Letnik:
16, Številka:
5
Journal Article
Recenzirano
We give a one-loop computation of a three-point amplitude of massless QED at small virtuality of a fermion. The result we obtain agrees with the classic Sudakov result, which we reproduce sending the ...second virtuality to zero.
The search for thermoelectric (TE) materials for highly efficient devices aims at improving the TE efficiency and broadening their areas of applications. We created nanostructured thermoelectric ...Bi-Sb-Te-family materials by high energy (ball milling) pre-treatment of the parent materials followed by high-pressure/high-temperature treatment. Bi₀.₅Sb₁.₅Te₃ compositions with the superfluous maintenance of tellurium was used for the synthesis of the samples with p-type electrical conductivity. Acoustic microscopy was used to study elastic properties and bulk irregularities and to detection of internal cracks both in the parent materials and in the created nanostructured samples. The data has been used for optimization of parameters of synthesis of nanostructured thermoelectrics.
Bulk nanostructured polycrystals are prospective thermoelectrics. Fabrication and examination of nanostructured polycrystalline
p
-Bi-Sb-Te are discussed. The influence of fabrication conditions and ...the composition of the material on sizes of nanograins was investigated experimentally. Basic physical properties of fabricated nanothermoelectrics including nanocomposites were also studied. Theoretical estimation of the influence of phonon scattering on nanograin boundaries in bulk nanostructured thermoelectrics is presented.
The paper is an attempt to review and clarify data concerning Mikhail Lomonosov’s grammar studies and especially the history of his famous “Russian Grammar”. The authors lay out the timeline of its ...creation and publication. They describe the main steps on its way from the author to the reader and discuss evidence of its manuscript versions. Scholars know of at least four handwritten copies, none of which survive or have been identified. Only a few related drafts known as “Manuscript 112” or “Materials to the Russian Grammar” are available in the archive of the Russian Academy of Sciences (published in volume 7 of his Lomonosov's Complete Works). The article examines two parts of this manuscript which were apparently written not by Lomonosov: 1) lists of words and drafts of sections devoted to different parts of speech; 2) comments on some paragraphs of the “Russian Grammar”. Comparison of handwriting samples shows that the first part was not, as previously suggested, written by Lomonosov’s long-time assistant and copyist Ivan Barkov, while the second part was probably written by Lomonosov's classmate and fellow worker at the Academy Aleksey Barsov. DOI: 10.31168/2305-6754.2019.8.2.7
Temperature-dependent strength of Bi-Sb-Te under uniaxial compression is investigated. Bi-Sb-Te samples were produced by three methods: vertical zone-melting, hot extrusion, and spark plasma ...sintering (SPS). For zone-melted and extruded samples, the brittle-ductile transition occurs over a temperature range of 200-350 °C. In nanostructured samples produced via SPS, the transition is observed in a narrower temperature range of 170-200 °C. At room temperature, the strength of the nanostructured samples is higher than that of zone-melted and extruded samples, but above 300 °C, all samples decrease to roughly the same strength.
New metal–nanocarbon composites were obtained by high-energy (ball milling) pre-treatment of the powder mixture followed by high-pressure/high-temperature treatment. Acoustic microscopy was used to ...study elastic properties and bulk irregularities of the samples.
Hardness and wear of ultra-and superhard fullerites and diamond were measured. The measured hardness was revealed 137±6 and 167±5 GPa for the diamond faces (100) and (111) respectively and that for ...the ultrahard fullerites was 290±30 and 310±40 GPa depending on synthesis conditions. The method of sclerometry (scratch at a constant indenter load) was used for the hardness measurements. The diamond surface (111) was deformed as a plastic material under the scratching with the ultrahard fullerite C
60 indenter at room temperature. A wear resistance of ultrahard fullerite ceramic in order exceeds that of polycrystal (carbonado-type) diamond. The results of hardness and wear measurements of ultra- and superhard fullerites show a good opportunity for processing of hard and superhard materials.
PDF
