62 research outputs found
The system of EAS time analysis
The extensive air showers' (EAS) front shape, angle of incidence, disk thickness, particle distribution along the shower, on the delayed and EAS front advancing particles were determined. The suggested system of the EAS time analysis allows determination of the whole EAS longitudinal structure at the observation points. The information from the detectors is continuously recorded in the memory with the memory cell switching in 5 ns, this enables fixation of the moment of pulse input from the detector with an accuracy to + or - 2.5 ns. Along with the fast memory, a slow memory with the cell switching in 1 micron s is introduced in the system, this permits observation of relatively large time intervals with respect to the trigger pulse with an appropriately lower accuracy
Disorder-induced tail states in a gapped bilayer graphene
The instanton approach to the in-gap fluctuation states is applied to the
spectrum of biased bilayer graphene. It is shown that the density of states
falls off with energy measured from the band-edge as , where the characteristic tail energy,
, scales with the concentration of impurities, , as
. While the bare energy spectrum is characterized by two energies:
the bias-induced gap, , and interlayer tunneling, , the tail,
, contains a {\it single} combination . We
show that the above expression for in the tail actually applies
all the way down to the mid-gap.Comment: 7 pages, 4 figure
Wightman function and vacuum densities for a Z_2-symmetric thick brane in AdS spacetime
Positive frequency Wightman function, vacuum expectation values of the field
square and the energy-momentum tensor induced by a Z_{2}-symmetric brane with
finite thickness located on (D+1)- dimensional AdS background are evaluated for
a massive scalar field with general curvature coupling parameter. For the
general case of static plane symmetric interior structure the expectation
values in the region outside the brane are presented as the sum of free AdS and
brane induced parts. For a conformally coupled massless scalar the brane
induced part in the vacuum energy-momentum tensor vanishes. In the limit of
strong gravitational fields the brane induced parts are exponentially
suppressed for points not too close to the brane boundary. As an application of
general results a special model is considered in which the geometry inside the
brane is a slice of the Minkowski spacetime orbifolded along the direction
perpendicular to the brane. For this model the Wightman function, vacuum
expectation values of the field square and the energy-momentum tensor inside
the brane are evaluated as well and their behavior is discussed in various
asymptotic regions of the parameters. It is shown that for both minimally and
conformally coupled scalar fields the interior vacuum forces acting on the
brane boundaries tend to decrease the brane thickness.Comment: 25 pages, 6 figures, discussion adde
Vacuum densities for a thick brane in AdS spacetime
For a massive scalar field with general curvature coupling parameter we
evaluate Wightman function, vacuum expectation values of the field square and
the energy-momentum tensor induced by a -symmetric brane with finite
thickness located on -dimensional AdS bulk. For the general case of
static plane symmetric interior structure the expectation values in the region
outside the brane are presented as the sum of free AdS and brane induced parts.
For a conformally coupled massless scalar the brane induced part in the vacuum
energy-momentum tensor vanishes. In the limit of strong gravitational fields
the brane induced parts are exponentially suppressed for points not too close
to the brane boundary. As an application of general results a special model is
considered in which the geometry inside the brane is a slice of the Minkowski
spacetime orbifolded along the direction perpendicular to the brane. For this
model the Wightman function, vacuum expectation values of the field square and
the energy-momentum tensor inside the brane are evaluated. It is shown that for
both minimally and conformally coupled scalar fields the interior vacuum forces
acting on the brane boundaries tend to decrease the brane thickness.Comment: 12 pages, 2 figures, talk presented at QFEXT07, Leipzig, September
17-21, 200
One-dimensional plasmons confined in bilayer graphene p-n junctions
Gapless spectrum of graphene allows easy spatial separation of electrons and
holes with an external in-plane electric field. Guided collective plasmon modes
can propagate along the separation line, whose amplitude decays with the
distance to it. Their spectrum and direction of propagation can be controlled
with the strength and direction of in-plane electric field. In case of a
bilayer graphene additional control is possible by the perpendicular electric
field that opens a gap in the band spectrum of electrons. We investigate guided
plasmon spectra in bilayer p-n junctions using hydrodynamics of charged
electron liquid.Comment: published version, minor change
Non-Bloch-Siegert-type power-induced shift of two-photon electron paramagnetic resonances of charge-carrier spin states in an OLED
We present Floquet theory-based predictions and electrically detected
magnetic resonance (EDMR) experiments scrutinizing the nature of two-photon
magnetic resonance shifts of charge-carrier spin states in the perdeuterated
-conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene
vinylene] (d-MEH-PPV) under strong magnetic resonant drive conditions
(radiation amplitude ~ Zeeman field ). Numerical calculations show
that the two-photon resonance shift with power is nearly drive-helicity
independent. This is in contrast to the one-photon Bloch-Siegert shift that
only occurs under non-circularly polarized strong drive conditions. We
therefore treated the Floquet Hamiltonian analytically under arbitrary
amplitudes of the co- and counter-rotating components of the radiation field to
gain insight into the nature of the helicity dependence of multi-photon
resonance shifts. In addition, we tested Floquet-theory predictions
experimentally by comparing one-photon and two-photon charge-carrier spin
resonance shifts observed through room-temperature EDMR experiments on
d-MEH-PPV-based bipolar injection devices [i.e., organic light emitting diode
structures (OLEDs)]. We found that under the experimental conditions of strong,
linearly polarized drive, our observations consistently agree with theory,
irrespective of the magnitude of , and therefore underscore the robustness
of Floquet theory in predicting nonlinear magnetic resonance behaviors.Comment: 22 pages, 5 figure
Assessment of the degree of dehydration in infectious gastroenteritis in young children
The article discusses two ways to determine the severity of the condition in infectious gastroenteritis. The possibility of using the VESIKARI scale for assessing the condition in children is being determined.В статье рассматривается два способа определения степени дегидратации при инфекционных гастроэнтеритах. Определяется возможность использования шкалы VESIKARI для оценки состояния у детей
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