35,656 research outputs found
Statistical comparisons of aircraft flyover noise adjustment procedures for different weather conditions
Aircraft flyover noise spectra and effective perceived noise level (EPNL) values obtained under widely different weather conditions were adjusted according to a proposed national standard. The results were statistically compared with the same measured spectra adjusted according to an alternate procedure and with reference spectra and EPNL values obtained under almost ideal weather conditions. Three different ways to represent the weather condition through which the sound propagated were also evaluated
Saturation and shadowing in high-energy proton-nucleus dilepton production
We discuss the inclusive dilepton cross section for proton (quark)-nucleus
collisions at high energies in the very forward rapidity region. Starting from
the calculation in the quasi-classical approximation, we include low-x
evolution effects in the nucleus and predict leading twist shadowing together
with anomalous scaling behaviour.Comment: 32 pages, LaTex, 6 figures, a few modifications of the tex
Does parton saturation at high density explain hadron multiplicities at LHC?
An addendum to our previous papers in Phys. Lett. B539 (2002) 46 and Phys.
Lett. B502 (2001) 51, contributed to the CERN meeting "First data from the LHC
heavy ion run", March 4, 2011Comment: 6 pages, contribution to the CERN meeting "First data from the LHC
heavy ion run", March 4, 201
Resonant photon absorption in the low spin molecule V15
We report the first study of the micro-SQUID response of a molecular system
to electromagnetic radiation. The advantages of our micro-SQUID technique in
respect to pulsed electron paramagnetic resonance (EPR) techniques consist in
the possibility to perform time-resolved experiments (below 1 ns) on
submicrometer sizes samples (about 1000 spins) at low temperature (below 100
mK).
Resonant photon absorption in the GHz range was observed via low temperature
micro-SQUID magnetization measurements of the spin ground state S = 1/2 of the
molecular complex V15. The line-width essentially results from intra-molecular
hyperfine interaction. The results point out that observing Rabi oscillations
in molecular nanomagnets requires well isolated low spin systems and high
radiation power. Our first results open the way for time-resolved observations
of quantum superposition of spin-up and spin-down states in SMMs.Comment: 7 pages, 5 figure
The Boltzmann Equation in Classical Yang-Mills Theory
We give a detailed derivation of the Boltzmann equation, and in particular
its collision integral, in classical field theory. We first carry this out in a
scalar theory with both cubic and quartic interactions and subsequently in a
Yang-Mills theory. Our method is not relied on a doubling of the fields, rather
it is based on a diagrammatic approach representing the classical solution to
the problem.Comment: 24 pages, 7 figures; v2: typos corrected, reference added, published
in Eur. Phys. J.
Elastomer coated filler and composites thereof comprising at least 60% by weight of a hydrated filler and an elastomer containing an acid substituent
The impact resistance of flame retardant composites, especially thermoplastic molding: compounds containing over 60% hydrated mineral filler such as Al(OH)3 or Mg(OH)2 as improved by coating the filler with 1 to 20% of an elastomer. The composite will fail by crazing or shearing rather than by brittle fracture. A well bonded elastomeric interphase resulted by utilizing acidic substituted resins such as ethyl-hexyl acrylate-acrylic acid copolymers which bond to and are cross-linked by the basic filler particles. Further improvement in impact resistance was provided by incorporating 1 to 10% of a resin fiber reinforcement such as polyvinyl alcohol fibers that decompose to yield at least 30% water when heated to decomposition temperature
Jet evolution from weak to strong coupling
Recent studies, using the AdS/CFT correspondence, of the radiation produced
by a decaying system or by an accelerated charge in the N=4 supersymmetric
Yang-Mills theory, led to a striking result: the 'supergravity backreaction',
which is supposed to describe the energy density at infinitely strong coupling,
yields exactly the same result as at zero coupling, that is, it shows no trace
of quantum broadening. We argue that this is not a real property of the
radiation at strong coupling, but an artifact of the backreaction calculation,
which is unable to faithfully capture the space-time distribution of the
radiation. This becomes obvious in the case of a decaying system ('virtual
photon'), for which the backreaction is tantamount to computing a three-point
function in the conformal gauge theory, which is independent of the coupling
since protected by symmetries. Whereas this non-renormalization property is
specific to the conformal N=4 SYM theory, we argue that the failure of the
three-point function to provide a local measurement is in fact generic: it
holds in any field theory with non-trivial interactions. To properly study a
localized distribution, one should rather compute a four-point function, as
standard in deep inelastic scattering. We substantiate these considerations
with studies of the radiation produced by the decay of a time-like photon at
both weak and strong coupling. We show that by computing four-point functions,
in perturbation theory at weak coupling and, respectively, from Witten diagrams
at strong coupling, one can follow the quantum evolution and thus demonstrate
the broadening of the energy distribution. This broadening is slow when the
coupling is weak but it proceeds as fast as possible in the limit of a strong
coupling.Comment: 49 pages, 6 figure
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