14,679 research outputs found
Inviscid flow field induced by a rotor in ground effect
Integral equations for inviscid flow field induced by rotor in ground effec
Scattering by nonspherical systems
Scattering by nonspherical particles with size of order of wavelength - scattering by axisymmetric penetrable particles using approximate matching of boundary condition
Tuning Nanocrystal Surface Depletion by Controlling Dopant Distribution as a Route Toward Enhanced Film Conductivity
Electron conduction through bare metal oxide nanocrystal (NC) films is
hindered by surface depletion regions resulting from the presence of surface
states. We control the radial dopant distribution in tin-doped indium oxide
(ITO) NCs as a means to manipulate the NC depletion width. We find in films of
ITO NCs of equal overall dopant concentration that those with dopant-enriched
surfaces show decreased depletion width and increased conductivity. Variable
temperature conductivity data shows electron localization length increases and
associated depletion width decreases monotonically with increased density of
dopants near the NC surface. We calculate band profiles for NCs of differing
radial dopant distributions and, in agreement with variable temperature
conductivity fits, find NCs with dopant-enriched surfaces have narrower
depletion widths and longer localization lengths than those with
dopant-enriched cores. Following amelioration of NC surface depletion by atomic
layer deposition of alumina, all films of equal overall dopant concentration
have similar conductivity. Variable temperature conductivity measurements on
alumina-capped films indicate all films behave as granular metals. Herein, we
conclude that dopant-enriched surfaces decrease the near-surface depletion
region, which directly increases the electron localization length and
conductivity of NC films
Non-Pauli Effects from Noncommutative Spacetimes
Noncommutative spacetimes lead to nonlocal quantum field theories (qft's)
where spin-statistics theorems cannot be proved. For this reason, and also
backed by detailed arguments, it has been suggested that they get corrected on
such spacetimes leading to small violations of the Pauli principle. In a recent
paper \cite{Pauli}, Pauli-forbidden transitions from spacetime noncommutativity
were calculated and confronted with experiments. Here we give details of the
computation missing from this paper. The latter was based on a spacetime
different from the Moyal plane. We argue that it
quantizes time in units of . Energy is then conserved only mod
. Issues related to superselection rules raised by non-Pauli
effects are also discussed in a preliminary manner.Comment: 15 Pages, 1 Table, Full details and further developments of
arXiv:1003.2250. This version is close to the one accepted by JHE
Searching for Saturn's Dust Swarm: Limits on the size distribution of Irregular Satellites from km to micron sizes
We describe a search for dust created in collisions between the Saturnian
irregular satellites using archival \emph{Spitzer} MIPS observations. Although
we detected a degree scale Saturn-centric excess that might be attributed to an
irregular satellite dust cloud, we attribute it to the far-field wings of the
PSF due to nearby Saturn. The Spitzer PSF is poorly characterised at such
radial distances, and we expect PSF characterisation to be the main issue for
future observations that aim to detect such dust. The observations place an
upper limit on the level of dust in the outer reaches of the Saturnian system,
and constrain how the size distribution extrapolates from the smallest known
(few km) size irregulars down to micron-size dust. Because the size
distribution is indicative of the strength properties of irregulars, we show
how our derived upper limit implies irregular satellite strengths more akin to
comets than asteroids. This conclusion is consistent with their presumed
capture from the outer regions of the Solar System.Comment: accepted to MNRA
Specificity characteristics of 7 commercial creatinine measurement procedures by enzymatic and jaffe method principles
Journal ArticleStandardized calibration does not change a creatinine measurement procedure?s susceptibility to potentially interfering substances
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