729 research outputs found
INCREASING THE LEVEL OF PHYSICAL AND MECHANICAL PROPERTIES OF COLD-ROLLED STEEL OF THE BRAND DC01 IN ORDER TO ENSURE ITS REQUIREMENTS EN 10130 IN THE CONDITIONS OF PJSC "ZAPORIZHSTAL"
Increasing the level of physical and mechanical properties of cold-
rolled steel
Linear, diatomic crystal: single-electron states and large-radius excitons
The large-radius exciton spectrum in a linear crystal with two atoms in the
unit cell was obtained using the single-electron eigenfunctions and the band
structure, which were found by the zero-range potential (ZRP) method. The
ground-state exciton binding energies for the crystal in vacuum appeared to be
larger than the corresponding energy gaps for any set of the crystal
parameters.Comment: 9 pages, 1 figure, 1 tabl
Diffraction radiation from a screen of finite conductivity
An exact solution has been found for the problem of diffraction radiation
appearing when a charged particle moves perpendicularly to a thin finite screen
having arbitrary conductivity and frequency dispersion. Expressions describing
the Diffraction and Cherenkov emission mechanisms have been obtained for the
spectral-angular forward and backward radiation densities.Comment: 6 pages, 4 figure
Incoherent form factor in diffraction and Smith - Purcell radiations
It has been shown that polarization radiation of charged particle beams generally includes an incoherent form factor caused by a finite transverse size of a beam. Consequently, a widespread opinion that the form factor characterizes only coherent radiation of charge particle bunches is generally invali
Near-field resonances in photon emission via interaction of electrons with coupled nanoparticles
In this work we construct the first-principles theory for the near-field resonances arising in the system of two different coupled nanoparticles excited by the external field. The obtained expressions are valid for an arbitrary external field; the detailed analysis is performed for the case of a fast electron passing b
Extensive infrared spectroscopic study of CuO: signatures of strong spin-phonon interaction and structural distortion
Optical properties of single-crystal monoclinic CuO in the range 70 - 6000
\cm were studied at temperatures from 7 to 300 K. Normal reflection spectra
were obtained from the (001) and (010) crystal faces thus giving for the first
time separate data for the and phonon modes excited in the
purely transverse way (TO modes). Mode parameters, including polarizations of
the modes not determined by the crystal symmetry, were extracted by the
dispersion analysis of reflectivity curves as a function of temperature.
Spectra of all the components of the optical conductivity tensor were obtained
using the Kramers-Kronig method recently extended to the case of the
low-symmetry crystals. The number of strong phonon modes is in agreement with
the factor-group analysis for the crystal structure, currently accepted for the
CuO. However, several "extra" modes of minor intensity are detected. Comparison
of frequencies of "extra" modes with the available phonon dispersion curves
points to possible "diagonal" doubling of the unit cell \{{\bf a}, {\bf b},
{\bf c}\} \{{\bf a}+{\bf c}, {\bf b}, {\bf a}-{\bf c}\} and formation of
the superlattice. The previously reported softening of the mode
( 400 \cm) with cooling at is found to be 10 % for the TO
mode. The mode is very broad at high temperatures and strongly narrows in the
AFM phase. We attribute this effect to strong resonance coupling of this mode
to optical or acoustic bi-magnons and reconstruction of the magnetic
excitations spectrum at the N\'eel point. A significant anisotropy of
is observed: it was found to be 5.9 along the {\bf b}-axis,
6.2 along the {[}101{]} chains and 7.8 the {[}10{]} chains. The
"transverse" effective charge is value is about 2 electrons.Comment: 23 pages, 14 figures, REVTeX, submitted to PR
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