27,473 research outputs found
New Limit for the Half-Life of 2K(2neutrino)-Capture Decay Mode of 78Kr
Features of data accumulated at 1817 hours in the experimental search for
2K(2 \nu)-capture decay mode of Kr-78 are discussed. The new limit for this
decay half-life is found to be T_{1/2} > 2.3 *10^{20} yr. (90% C.L.).Comment: 7 pages, 4 figures, submitted to Phys. of Atom. Nuc
Generation and Characterization of a Tissue-Specific Centrosome Indicator Mouse Line.
Centrosomes are major microtubule organizing centers (MTOCs) that play an important role in chromosome segregation during cell division. Centrosomes provide a stable anchor for microtubules, constituting the centers of the spindle poles in mitotic cells, and determining the orientation of cell division. However, visualization of centrosomes is challenging because of their small size. Especially in mouse tissues, it has been extremely challenging to observe centrosomes belonging to a specific cell type of interest among multiple comingled cell types. To overcome this obstacle, we generated a tissue-specific centrosome indicator. In this mouse line, a construct containing a floxed neomyocin resistance gene with a triplicate polyA sequence followed by an EGFP-Centrin1 fusion cassette was knocked into the Rosa locus. Upon Cre-mediated excision, EGFP-Centrin1 was expressed under the control of the Rosa locus. Experiments utilizing mouse embryo fibroblasts (MEFs) demonstrated the feasibility of real-time imaging, and showed that EGFP-Centrin1 expression mirrored the endogenous centrosome cycle, undergoing precisely one round of duplication through the cell cycle. Moreover, experiments using embryo and adult mouse tissues demonstrated that EGFP-Centrin1 specifically mirrors the localization of endogenous centrosomes. genesis 54:286-296, 2016. © 2016 The Authors. Genesis Published by Wiley Periodicals, Inc
Non-perturbation theory of electronic dynamic conductivity for two-barrier resonance tunnel nano-structure
The non-perturbation theory of electronic dynamic conductivity for open
two-barrier resonance tunnel structure is established for the first time within
the model of rectangular potentials and different effective masses of electrons
in the elements of nano-structure and the wave function linear over the
intensity of electromagnetic field. It is proven that the results of the theory
of dynamic conductivity, developed earlier in weak signal approximation within
the perturbation method, qualitatively and quantitatively correlate with the
obtained results. The advantage of non-perturbation theory is that it can be
extended to the case of electronic currents interacting with strong
electromagnetic fields in open multi-shell resonance tunnel nano-structures, as
active elements of quantum cascade lasers and detectors.Comment: 10 pages, 2 figure
Quasi-stationary states of electrons interacting with strong electromagnetic field in two-barrier resonance tunnel nano-structure
An exact solution of non-stationary Schrodinger equation is obtained for a
one-dimensional movement of electrons in an electromagnetic field with
arbitrary intensity and frequency. Using it, the permeability coefficient is
calculated for a two-barrier resonance tunnel nano-structure placed into a
high-frequency electromagnetic field. It is shown that a nano-structure
contains quasi-stationary states the spectrum of which consists of the main and
satellite energies. The properties of resonance and non-resonance channels of
permeability are displayed.Comment: 8 pages, 3 figure
Spin Distribution in Diffraction Pattern of Two-dimensional Electron Gas with Spin-orbit Coupling
Spin distribution in the diffraction pattern of two-dimensional electron gas
by a split gate and a quantum point contact is computed in the presence of the
spin-orbit coupling. After diffracted, the component of spin perpendicular to
the two-dimensional plane can be generated up to 0.42 . The non-trivial
spin distribution is the consequence of a pure spin current in the transverse
direction generated by the diffraction. The direction of the spin current can
be controlled by tuning the chemical potential.Comment: 9 page
Energy spectrum of localized quasiparticles renormalized by multi-phonon processes at finite temperature
The theory of renormalized energy spectrum of localized quasi-particle
interacting with polarization phonons at finite temperature is developed within
the Feynman-Pines diagram technique. The created computer program effectively
takes into account multi-phonon processes, exactly defining all diagrams of
mass operator together with their analytical expressions in arbitrary order
over the coupling constant. Now it is possible to separate the pole and
non-pole mass operator terms and perform a partial summing of their main terms.
The renormalized spectrum of the system is obtained within the solution of
dispersion equation in the vicinity of the main state where the high- and
low-energy complexes of bound states are observed. The properties of the
spectrum are analyzed depending on the coupling constant and the temperature.Comment: 16 pages, 3 figures, 3 table
Renormalized energy of ground and first excited state of Fr\"{o}hlich polaron in the range of weak coupling
Partial summing of infinite range of diagrams for the two-phonon mass
operator of polaron described by Fr\"{o}hlich Hamiltonian is performed using
the Feynman-Pines diagram technique. Renormalized spectral parameters of ground
and first excited (phonon repeat) polaron state are accurately calculated for a
weak electron-phonon coupling at K. It is shown that the stronger
electron-phonon interaction shifts the energy of both states into low-energy
region of the spectra. The ground state stays stationary and the excited one
decays at a bigger coupling constant.Comment: 12 pages, 5 figure
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