6,660 research outputs found
Improved thermally conducting electron transfer polymers
Development of polymers with improved heat transfer coefficients for use in encapsulating electronic modules is discussed. Chemical reactions for synthesizing the polymers are described and thermodynamic and physical properties are analyzed
Thermally conducting electron transfer polymers
New polymeric material exhibits excellent physical shock protection, high electrical resistance, and thermal conductivity. It is especially useful for electronic circuitry, such as subminiaturization of components and modular construction of circuits
Fusion at deep subbarrier energies: potential inversion revisited
For a single potential barrier, the barrier penetrability can be inverted
based on the WKB approximation to yield the barrier thickness. We apply this
method to heavy-ion fusion reactions at energies well below the Coulomb barrier
and directly determine the inter-nucleus potential between the colliding
nuclei. To this end, we assume that fusion cross sections at deep subbarrier
energies are governed by the lowest barrier in the barrier distribution. The
inverted inter-nucleus potentials for the O +Sm and O
+Pb reactions show that they are much thicker than phenomenological
potentials. We discuss a consequence of such thick potential by fitting the
inverted potentials with the Bass function.Comment: 8 pages, 5 figures. Uses aipxfm.sty. A talk given at the FUSION08:
New Aspects of Heavy Ion Collisions Near the Coulomb Barrier, September
22-26, 2008, Chicago, US
Triple Products and Yang-Baxter Equation (II): Orthogonal and Symplectic Ternary Systems
We generalize the result of the preceeding paper and solve the Yang-Baxter
equation in terms of triple systems called orthogonal and symplectic ternary
systems. In this way, we found several other new solutions.Comment: 38 page
Possible Detection of Apparent Superluminal inward motion in Markarian 421 after the Giant X-ray flare in February, 2010
We report on the VLBI follow-up observations using the Japanese VLBI Network
(JVN) array at 22 GHz for the largest X-ray flare of TeV blazar Mrk 421 that
occurred in mid-February, 2010. The total of five epochs of observations were
performed at intervals of about 20 days between March 7 and May 31, 2010. No
new-born component associated with the flare was seen directly in the total
intensity images obtained by our multi-epoch VLBI observations. However, one
jet component located at ~1 mas north-west from the core was able to be
identified, and its proper motion can be measured as -1.66+/-0.46 mas yr^-1,
which corresponds to an apparent velocity of -3.48+/-0.97 c. Here, this
negative velocity indicates that the jet component was apparently moving toward
the core. As the most plausible explanation, we discuss that the apparent
negative velocity was possibly caused by the ejection of a new component, which
could not be resolved with our observations. In this case, the obtained Doppler
factor of the new component is around 10 to 20, which is consistent with the
ones typically estimated by model fittings of spectral energy distribution for
this source.Comment: 9 pages, 6 figures, 3 tables, accepted for publication in Ap
Faraday rotation in the MOJAVE blazars: 3C 273 a case study
Radio polarimetric observations of Active Galactic Nuclei can reveal the
magnetic field structure in the parsec-scale jets of these sources. We have
observed the gamma-ray blazar 3C 273 as part of our multi-frequency survey with
the Very Long Baseline Array to study Faraday rotation in a large sample of
jets. Our observations re-confirm the transverse rotation measure gradient in
3C 273. For the first time the gradient is seen to cross zero which is further
indication for a helical magnetic field and spine-sheath structure in the jet.
We believe the difference to previous epochs is due to a different part of the
jet being illuminated in our observations.Comment: 6 pages, 3 figures. To appear in the proceedings of "Beamed and
Unbeamed Gamma-rays from Galaxies", held in Muonio, Finland, April 11-15,
2011. Journal of Physics: Conference Serie
OnabotulinumtoxinA in the treatment of overactive bladder: a cost-effectiveness analysis versus best supportive care in England and Wales
The cost-effectiveness of onabotulinumtoxinA (BOTOX®) 100 U + best supportive care (BSC) was compared with BSC alone in the management of idiopathic overactive bladder in adult patients who are not adequately managed with anticholinergics. BSC included incontinence pads and, for a proportion of patients, anticholinergics and/or occasional clean intermittent catheterisation. A five-state Markov model was used to estimate total costs and outcomes over a 10-year period. The cohort was based on data from two placebo-controlled trials and a long-term extension study of onabotulinumtoxinA. After discontinuation of initial treatment, a proportion of patients progressed to downstream sacral nerve stimulation (SNS). Cost and resource use was estimated from a National Health Service perspective in England and Wales using relevant reference sources for 2012 or 2013. Results showed that onabotulinumtoxinA was associated with lower costs and greater health benefits than BSC in the base case, with probabilistic sensitivity analysis indicating an 89 % probability that the incremental cost-effectiveness ratio would fall below £20,000. OnabotulinumtoxinA remained dominant over BSC in all but two scenarios tested; it was also economically dominant when compared directly with SNS therapy. In conclusion, onabotulinumtoxinA appears to be a cost-effective treatment for overactive bladder compared with BSC alone
The Weak Clustering of Gas-Rich Galaxies
We examine the clustering properties of HI-selected galaxies through an
analysis of the HI Parkes All-Sky Survey Catalogue (HICAT) two-point
correlation function. Various sub-samples are extracted from this catalogue to
study the overall clustering of HI-rich galaxies and its dependence on
luminosity, HI gas mass and rotational velocity. These samples cover the entire
southern sky Dec < 0 deg, containing up to 4,174 galaxies over the radial
velocity range 300-12,700 km/s. A scale length of r_0 = 3.45 +/- 0.25 Mpc/h and
slope of gamma = 1.47 +/- 0.08 is obtained for the HI-rich galaxy real-space
correlation function, making gas-rich galaxies among the most weakly clustered
objects known. HI-selected galaxies also exhibit weaker clustering than
optically selected galaxies of comparable luminosities. Good agreement is found
between our results and those of synthetic HI-rich galaxy catalogues generated
from the Millennium Run CDM simulation. Bisecting HICAT using different
parameter cuts, clustering is found to depend most strongly on rotational
velocity and luminosity, while the dependency on HI mass is marginal. Splitting
the sample around v_rot = 108 km/s, a scale length of r_0 = 2.86 +/- 0.46 Mpc/h
is found for galaxies with low rotational velocities compared to r_0 = 3.96 +/-
0.33 Mpc/h for the high rotational velocity sample.Comment: Accepted for publication in the Astrophysical Journa
Neutral Hydrogen Clouds near Early-Type Dwarf Galaxies of the Local Group
Parkes neutral hydrogen 21 cm line (HI) observations of the surroundings of 9
early-type Local Group dwarfs are presented. We detected numerous HI clouds in
the general direction of those dwarfs and these clouds are often offset from
the optical center of the galaxies. Although all the observed dwarfs, except
Antlia, occupy phase-space regions where the High-Velocity Cloud (HVC) density
is well above average, the measured offsets are smaller than one would expect
from a fully random cloud distribution. Possible association is detected for 11
of the 16 investigated clouds, while, for two galaxies, Sextans and Leo I, no
HI was detected. The galaxies where HI clouds were found not to coincide with
the optical, yet have a significant probability of being associated are:
Sculptor dSph, Tucanna, LGS3, Cetus, and Fornax. If the clouds are indeed
associated, these galaxies have HI masses of ,
, , , and , respectively.
However, neither ram pressure nor tidal stripping can easily explain the
offsets. In some cases, large offsets are found where ram pressure should be
the least effective.Comment: Accepted in AJ, June 200
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