329 research outputs found
Derivation of Amplitude Equations by Renormalization Group Method
A proper formulation in the perturbative renormalization group method is
presented to deduce amplitude equations. The formulation makes it possible not
only avoiding a serious difficulty in the previous reduction to amplitude
equations by eliminating all of the secular terms but also consistent
derivation of higher-order correction to amplitude equations.Comment: 6 page, revte
X-ray Dust Scattering at Small Angles: The Complete Halo around GX13+1
The exquisite angular resolution available with Chandra should allow
precision measurements of faint diffuse emission surrounding bright sources,
such as the X-ray scattering halos created by interstellar dust. However, the
ACIS CCDs suffer from pileup when observing bright sources, and this creates
difficulties when trying to extract the scattered halo near the source. The
initial study of the X-ray halo around GX13+1 using only the ACIS-I detector
done by Smith, Edgar & Shafer (2002) suffered from a lack of sensitivity within
50'' of the source, limiting what conclusions could be drawn.
To address this problem, observations of GX13+1 were obtained with the
Chandra HRC-I and simultaneously with the RXTE PCA. Combined with the existing
ACIS-I data, this allowed measurements of the X-ray halo between 2-1000''.
After considering a range of dust models, each assumed to be smoothly
distributed with or without a dense cloud along the line of sight, the results
show that there is no evidence in this data for a dense cloud near the source,
as suggested by Xiang et al. (2005). Finally, although no model leads to
formally acceptable results, the Weingartner & Draine (2001) and nearly all of
the composite grain models from Zubko, Dwek & Arendt (2004) give poor fits.Comment: 8 pages, 6 figures, accepted for publication in Ap
Anti-phase Modulation of Electron- and Hole-like States in Vortex Core of Bi2Sr2CaCu2Ox Probed by Scanning Tunneling Spectroscopy
In the vortex core of slightly overdoped Bi2Sr2CaCu2Ox, the electron-like and
hole-like states have been found to exhibit spatial modulations in anti-phase
with each other along the Cu-O bonding direction. Some kind of
one-dimensionality has been observed in the vortex core, and it is more clearly
seen in differential conductance maps at lower biases below +-9 mV
Renormalization Group Method and Reductive Perturbation Method
It is shown that the renormalization group method does not necessarily
eliminate all secular terms in perturbation series to partial differential
equations and a functional subspace of renormalizable secular solutions
corresponds to a choice of scales of independent variables in the reductive
perturbation method.Comment: 5 pages, late
Lithium production on a low-mass secondary in a black hole soft X-ray transient
We examine production of Li on the surface of a low-mass secondary in a black
hole soft X-ray transient (BHSXT) through the spallation of CNO nuclei by
neutrons which are ejected from a hot (> 10 MeV) advection-dominated accretion
flow (ADAF) around the black hole. Using updated binary parameters, cross
sections of neutron-induced spallation reactions, and mass accretion rates in
ADAF derived from the spectrum fitting of multi-wavelength observations of
quiescent BHSXTs, we obtain the equilibrium abundances of Li by equating the
production rate of Li and the mass transfer rate through accretion to the black
hole. The resulting abundances are found to be in good agreement with the
observed values in seven BHSXTs. We note that the abundances vary in a
timescale longer than a few months in our model. Moreover, the isotopic ratio
Li6/Li7 is calculated to be about 0.7--0.8 on the secondaries, which is much
higher than the ratio measured in meteorites. Detection of such a high value is
favorable to the production of Li via spallation and the existence of a hot
accretion flow, rather than an accretion disk corona system in quiescent BHSXT.Comment: 4 pages, 3 figures, and 2 tables, submitted to Astrophyscal Jounal
Letter
Optimised Curing of Silver Ink Jet Based Printed Traces
Manufacturing electronic devices by printing techniques with low temperature
sintering of nano-size material particles can revolutionize the electronics
industry in coming years. The impact of this change to the industry can be
significant enabling low-cost products and flexibility in manufacturing.
implementation of a new production technology with new materials requires
thorough elementary knowledge creation. It should be noticed that although some
of first electronic devices ideally can be manufactured by printing, at the
present several modules are in fact manufactured by using hybrid techniques
(for instance photolithography, vapor depositions, spraying, etc...).Comment: Submitted on behalf of TIMA Editions
(http://irevues.inist.fr/tima-editions
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