299 research outputs found
Selection rules for Raman-active electronic excitations in carbon nanotubes
Raman measurements in carbon allotropes are generally associated with the
exploration of the vibrational modes. Here, we present a theory of the
non-resonant inelastic light scattering accompanied by the excitations of
intersubband electron-hole pairs in carbon nanotubes and predict the selection
rules and polarization properties of the dominant intersubband Raman active
modes.Comment: 4 pages, 3 figure
Signature of electronic excitations in the Raman spectrum of graphene
Inelastic light scattering from Dirac-type electrons in graphene is shown to
be dominated by the generation of the inter-band electronic modes which are odd
in terms of time-inversion symmetry and belong to the irreducible
representation A of the point group C of the honeycomb crystal. At
high magnetic fields, these electron-hole excitations appear as peculiar inter-Landau-level modes with energies and characteristically crossed polarisation of in/out photons.Comment: 4 pages, 2 figures, revised and improve
Thermally excited spin-current in metals with embedded ferromagnetic nanoclusters
We show that a thermally excited spin-current naturally appears in metals
with embedded ferromagnetic nanoclusters. When such materials are subjected to
a magnetic field, a spin current can be generated by a temperature gradient
across the sample as a signature of electron-hole symmetry breaking in a metal
due to the electron spin-flip scattering from polarised magnetic moments. Such
a spin current can be observed via a giant magneto-thermopower which tracks the
polarisation state of the magnetic subsystem and is proportional to the
magnetoresistance. Our theory explains the recent experiment on Co clusters in
copper by S. Serrano-Guisan \textit{et al} [Nature Materials AOP,
doi:10.1038/nmat1713 (2006)
Contractions of low-dimensional nilpotent Jordan algebras
In this paper we classify the laws of three-dimensional and four-dimensional
nilpotent Jordan algebras over the field of complex numbers. We describe the
irreducible components of their algebraic varieties and extend contractions and
deformations among them. In particular, we prove that J2 and J3 are irreducible
and that J4 is the union of the Zariski closures of two rigid Jordan algebras.Comment: 12 pages, 3 figure
Spectral features due to inter-Landau-level transitions in the Raman spectrum of bilayer graphene
We investigate the contribution of the low-energy electronic excitations
towards the Raman spectrum of bilayer graphene for the incoming photon energy
Omega >> 1eV. Starting with the four-band tight-binding model, we derive an
effective scattering amplitude that can be incorporated into the commonly used
two-band approximation. Due to the influence of the high-energy bands, this
effective scattering amplitude is different from the contact interaction
amplitude obtained within the two-band model alone. We then calculate the
spectral density of the inelastic light scattering accompanied by the
excitation of electron-hole pairs in bilayer graphene. In the absence of a
magnetic field, due to the parabolic dispersion of the low-energy bands in a
bilayer crystal, this contribution is constant and in doped structures has a
threshold at twice the Fermi energy. In an external magnetic field, the
dominant Raman-active modes are the n_{-} to n_{+} inter-Landau-level
transitions with crossed polarisation of in/out photons. We estimate the
quantum efficiency of a single n_{-} to n_{+} transition in the magnetic field
of 10T as I_{n_{-} to n_{+}}~10^{-12}.Comment: 7 pages, 3 figures, expanded version published in PR
Overexpression of MRPS18-2 in cancer cell lines results in appearance of multinucleated cells
Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Human mitochondrial ribosomal protein MRPS18-2 (S18-2) is encoded by a cellular gene that is located on the human chromosome 6p21.3. We discovered that overexpression of the S18-2 protein led to immortalization and de-differentiation of primary rat embryonic fibroblasts. Cells showed anchorage-independent growth pattern. Moreover, pathways characteristic for rapidly proliferating cells were upregulated then. It is possible that the S18-2 overexpression induced disturbance in cell cycle regulation. We found that overexpression of S18-2 protein in human cancer cell lines led to an appearance of multinucleated cells in the selected clones.publishersversionPeer reviewe
Variety of Jordan algebras in small dimensions
The variety J orn of Jordan unitary algebra
structures on k
n , k an algebraically closed field with char k 6= 2 ,
is studied, as well as infinitesimal deformations of Jordan algebras.
Also we establish the list of GLn-orbits on J orn, n = 4, 5 under
the action of structural transport. The numbers jor₄ and jor₅ of
irreducible components are 3 and 6 respectively; a list of generic
structures is included
On E-functions of Semisimple Lie Groups
We develop and describe continuous and discrete transforms of class functions
on a compact semisimple, but not simple, Lie group as their expansions into
series of special functions that are invariant under the action of the even
subgroup of the Weyl group of . We distinguish two cases of even Weyl groups
-- one is the direct product of even Weyl groups of simple components of ,
the second is the full even Weyl group of . The problem is rather simple in
two dimensions. It is much richer in dimensions greater than two -- we describe
in detail transforms of semisimple Lie groups of rank 3.Comment: 17 pages, 2 figure
Features of the sales activity system
Improvement of marketing policy is one of the most important points in strategic planning of enterprise development, because the efficiency of planning of marketing activity depends on the result of activity of the whole enterprise
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