18,832 research outputs found
Degradation of multiplier phototubes exposed to spatial radiations
Degradation of multiplier phototubes exposed to spatial radiation
Dilaton Stabilization and Inflation in the D-brane World
We study the dilaton stabilization in the D-brane world in which a D-brane
constitutes our universe. The dilaton can be stabilized due to the interplay
between the D-brane tension and the negative scalar curvature of extra
dimensions. Cosmic evolution of the dilaton is investigated with the obtained
dilaton potential and it is found that inflation can be realized before the
settlement of the dilaton.Comment: 10 pages, abstract correcte
Cauchy problem for the Boltzmann-BGK model near a global Maxwellian
In this paper, we are interested in the Cauchy problem for the Boltzmann-BGK
model for a general class of collision frequencies. We prove that the
Boltzmann-BGK model linearized around a global Maxwellian admits a unique
global smooth solution if the initial perturbation is sufficiently small in a
high order energy norm. We also establish an asymptotic decay estimate and
uniform -stability for nonlinear perturbations.Comment: 26 page
Neutron and muon-induced background studies for the AMoRE double-beta decay experiment
AMoRE (Advanced Mo-based Rare process Experiment) is an experiment to search
a neutrinoless double-beta decay of Mo in molybdate crystals. The
neutron and muon-induced backgrounds are crucial to obtain the zero-background
level (< counts/(keVkgyr)) for the AMoRE-II experiment,
which is the second phase of the AMoRE project, planned to run at YEMI
underground laboratory. To evaluate the effects of neutron and muon-induced
backgrounds, we performed Geant4 Monte Carlo simulations and studied a
shielding strategy for the AMORE-II experiment. Neutron-induced backgrounds
were also included in the study. In this paper, we estimated the background
level in the presence of possible shielding structures, which meet the
background requirement for the AMoRE-II experiment
Taste symmetry breaking with HYP-smeared staggered fermions
We study the impact of hypercubic (HYP) smearing on the size of taste
breaking for staggered fermions, comparing to unimproved and to asqtad-improved
staggered fermions. As in previous studies, we find a substantial reduction in
taste-breaking compared to unimproved staggered fermions (by a factor of 4-7 on
lattices with spacing fm). In addition, we observe that
discretization effects of next-to-leading order in the chiral expansion () are markedly reduced by HYP smearing. Compared to asqtad valence
fermions, we find that taste-breaking in the pion spectrum is reduced by a
factor of 2.5-3, down to a level comparable to the expected size of generic
effects. Our results suggest that, once one reaches a lattice
spacing of fm, taste-breaking will be small enough after HYP
smearing that one can use a modified power counting in which , simplify fitting to phenomenologically interesting quantities.Comment: 14 pages, 13 figures, references updated, minor change
Subthreshold characteristics of pentacene field-effect transistors influenced by grain boundaries.
Grain boundaries in polycrystalline pentacene films significantly affect the electrical characteristics of pentacene field-effect transistors (FETs). Upon reversal of the gate voltage sweep direction, pentacene FETs exhibited hysteretic behaviours in the subthreshold region, which was more pronounced for the FET having smaller pentacene grains. No shift in the flat-band voltage of the metal-insulator-semiconductor capacitor elucidates that the observed hysteresis was mainly caused by the influence of localized trap states existing at pentacene grain boundaries. From the results of continuous on/off switching operation of the pentacene FETs, hole depletion during the off period is found to be limited by pentacene grain boundaries. It is suggested that the polycrystalline nature of a pentacene film plays an important role on the dynamic characteristics of pentacene FETs
- …