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11.
A. V. Inyushkin V. G. Ralchenko A. N. Taldenkov A. A. Artyukhov A. A. Artyukhov Ya. M. Kravets I. P. Gnidoi A. L. Ustinov A. P. Bolshakov A. F. Popovich A. V. Savelyev A. V. Khomich V. Ya. Panchenko V. I. Konov 《Bulletin of the Lebedev Physics Institute》2007,34(11):329-333
We measured the temperature dependence of thermal conductivity of a polycrystalline CVD diamond with natural isotope composition and an isotope enriched (99.96% 12C) sample at temperatures from 5 to 420 K. The isotope enriched diamond demonstrates a considerable growth of thermal conductivity at temperatures above 80 K compared to the diamond with natural composition of isotopes. At room temperature the thermal conductivity reaches 24.3 W·cm?1K?1, and the isotope effect makes up not less than 34%. 相似文献
12.
Boris A. Trofimov Lyubov'' N. Sobenina Zinaida V. Stepanova Tamara I. Vakul''skaya Ol''ga N. Kazheva Grigorii G. Aleksandrov Oleg A. Dyachenko Al''bina I. Mikhaleva 《Tetrahedron》2008,64(23):5541-5544
The solvent-free interaction of 2-phenylpyrrole with bromobenzoylacetylene (room temperature) upon their grinding with solid metal oxides (MgO, CaO, ZnO, BaO, Al2O3, TiO2, ZrO2) and salts (CaCO3, ZrSiO4) leads to either the cross-coupling product or the adduct of pyrrole addition to the riple bond of acetylene. The ethynylation is accompanied by the formation of intermediate and side products: E-2-(1-bromo-2-benzoylethenyl)-5-phenylpyrrole and 1,1-di(5-phenylpyrrol-2-yl)-2-benzoylethene. The activity of the metal oxides in the ethynylation reaction falls in the order (in the brackets, the content of 2-benzoylethynyl-5-phenylpyrrole in the reaction mixture is given): ZnO (81%), BaO (73%), Al2O3 (71%), MgO (69%), CaO (50%). The oxides, SiO2, TiO2, ZrO2, and the salts, CaCO3 and ZrSiO4, are inactive in the ethynylation reaction affording only the intermediate adduct, with ZrO2 the isolated yield of the bromoethenylpyrrole reaching 60%. ESR monitoring shows the reaction to start from one electron transfer from pyrrole to acetylene mediated by the oxide surface. The adduct is readily converted on Al2O3 to 2-(benzoylethynyl)-5-phenylpyrrole crystallized mostly as cis-rotamer (X-ray data). 相似文献
13.
Kravets L. I. Dmitriev S. N. Satulu V. Mitu B. Dinescu G. 《Russian Journal of Applied Chemistry》2010,83(9):1628-1635
Structure and electrotransport properties of poly(ethylene terephthalate) track membranes modified in pyrrole plasma were
studied. Physicochemical aspects of the conductivity asymmetry arising from the contact of two layers with functional groups
of different nature and from changes in the pore geometry are discussed. 相似文献
14.
15.
An experimental study was made of some schemes for flow around multiwedge bodies at supersonic flow velocities. On the basis of data on the distribution of the pressure, on visualization of the flow, and on optical measurements, an analysis was made of the structure of the flow. Zones of breakaway of the flow were observed at the lateral surfaces of the lobes. In the nose part of a multiwedge body there is a three-dimensional configuration of attached plane shock waves, going over into a combined detached nonaxisymmetric wave directed toward the base of the body. 相似文献
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17.
A magnetoimpedance effect is observed in Co80–xNixB20 (x = 4, 6, 8, 10, 12) amorphous metal alloy ribbons when an alternating current at frequencies ranging from 1–3000 kHz is passed
through samples in an external magnetic field. Spectra of the permittivity and optical conductivity of the surface of ribbons
of these alloys are obtained for incident photon energies of 1.0–5.0 eV. The relationships between the magnitude of the magnetoimpedance
effect, and the magnetic properties, electronic structure parameters, and optical characteristics of the amorphous alloy samples
are determined. 相似文献
18.
V. G. Kravets 《Optics and Spectroscopy》2013,114(2):230-235
The photoluminescence, IR transmission, and Raman scattering spectra of nc-Si nanocrystals (5 nm in size) have been investigated. The shape and spectral position of maxima in the photoluminescence and IR transmission spectra are theoretically described. It is shown that nc-Si particles consist of a Si core and a SiO2 shell. The existence of surface Si-O and Si-H states in Si nanocrystals enhances photoluminescence. It is established that the spectral position of the main Raman scattering peak in the frequency range 500–520 cm?1 undergoes a significant red shift for small-size nanostructures. Based on direct determination of the complex refractive index of n-Si nanoparticles by measuring spectral ellipsometric parameters, nanostructured silicon is found to be an indirect-gap semiconductor. 相似文献
19.
We experimentally demonstrate extremely narrow plasmon resonances with half-width of just several nanometers in regular arrays of metallic nanoparticles. These resonances are observed at Rayleigh's cutoff wavelengths for Wood anomalies and based on diffraction coupling of localized plasmons. We show experimentally that reflection from an array of nanoparticles can be completely suppressed at certain wavelengths. As a result, our metal nanostructures exhibit pi-jump for the phase of the reflected light. 相似文献
20.
Kravets L. I. Yarmolenko M. A. Rogachev A. V. Gainutdinov R. V. Altynov V. A. Lizunov N. E. 《Colloid Journal》2022,84(4):427-444
Colloid Journal - Different methods have been considered for the formation of coatings on the surface of a hydrophilic poly(ethylene terephthalate) track-etched membrane with the help of... 相似文献