1,434 research outputs found
Interface relaxation in electrophoretic deposition of polymer chains: Effects of segmental dynamics, molecular weight, and field
Using different segmental dynamics and relaxation, characteristics of the
interface growth is examined in an electrophoretic deposition of polymer chains
on a three (2+1) dimensional discrete lattice with a Monte Carlo simulation.
Incorporation of faster modes such as crankshaft and reptation movements along
with the relatively slow kink-jump dynamics seems crucial in relaxing the
interface width. As the continuously released polymer chains are driven (via
segmental movements) and deposited, the interface width grows with the
number of time steps , (--,
which is followed by its saturation to a steady-state value . Stopping the
release of additional chains after saturation while continuing the segmental
movements relaxes the saturated width to an equilibrium value ().
Scaling of the relaxed interface width with the driving field , remains similar to that of the steady-state width. In
contrast to monotonic increase of the steady-state width , the relaxed
interface width is found to decay (possibly as a stretched exponential)
with the molecular weight.Comment: 5 pages, 7 figure
Design of Pre-Dumping Ring Spin Rotator with a Possibility of Helicity Switching for Polarized Positrons at the ILC
The use of polarized beams enhance the possibility of the precision
measurements at the International Linear Collider (ILC). In order to preserve
the degree of polarization during beam transport spin rotators are included in
the current TDR ILC Lattice. In this report some advantages of using a combined
spin rotator/spin flipper are discussed. A few possible lattice designs of spin
flipper developed at DESY in 2012 are presented.Comment: Talk presented at the International Workshop on Future Linear
Colliders (LCWS15), Whistler, Canada, 2-6 November 201
On the degrees of freedom of a semi-Riemannian metric
A semi-Riemannian metric in a n-manifold has n(n-1)/2 degrees of freedom,
i.e. as many as the number of components of a differential 2-form. We prove
that any semi-Riemannian metric can be obtained as a deformation of a constant
curvature metric, this deformation being parametrized by a 2-for
Two-Fermion Production in Electron-Positron Collisions
This report summarizes the results of the two-fermion working group of the
LEP2-MC workshop, held at CERN from 1999 to 2000. Recent developments in the
theoretical calculations of the two fermion production process in the
electron-positron collision at LEP2 center of the mass energies are reported.
The Bhabha process and the production of muon, tau, neutrino and quark pairs is
covered. On the basis of comparison of various calculations, theoretical
uncertainties are estimated and compared with those needed for the final LEP2
data analysis. The subjects for the further studies are identified.Comment: 2-fermion working group report of the LEP2 Monte Carlo Workshop
1999/2000, 113 pages, 24 figures, 35 table
WW Cross-sections and Distributions
We present the results obtained by the "WW Cross-sections and Distributions"
working group during the CERN Workshop "Physics at LEP2" (1994/1995)Comment: 61 pages, tar'ed gzip'ed uuencoded files, LaTeX, 4 Postscript
figures. To appear in "Physics at LEP2", G.Altarelli and F.Zwirner eds., CERN
Report 199
Riemann's theorem for quantum tilted rotors
The angular momentum, angular velocity, Kelvin circulation, and vortex
velocity vectors of a quantum Riemann rotor are proven to be either (1) aligned
with a principal axis or (2) lie in a principal plane of the inertia ellipsoid.
In the second case, the ratios of the components of the Kelvin circulation to
the corresponding components of the angular momentum, and the ratios of the
components of the angular velocity to those of the vortex velocity are analytic
functions of the axes lengths.Comment: 8 pages, Phys. Rev.
A systematic review and network meta-analysis of randomized controlled trials evaluating the evidence base of melatonin, light exposure, exercise, and complementary and alternative medicine for patients with insomnia disorder
Insomnia is a prevalent disorder and it leads to relevant impairment in health-related quality of life. Recent clinical guidelines pointed out that Cognitive-Behavior Therapy for Insomnia (CBT-I) should be considered as first-line intervention. Nevertheless, many other interventions are commonly used by patients or have been proposed as effective for insomnia. These include melatonin, light exposure, exercise, and complementary and alternative medicine. Evaluation of comparable effectiveness of these interventions with first-line intervention for insomnia is however still lacking. We conducted a systematic review and network meta-analysis on the effects of these interventions. PubMed, PsycInfo, PsycArticles, MEDLINE, and CINAHL were systematically searched and 40 studies were included in the systematic review, while 36 were entered into the meta-analysis. Eight network meta-analyses were conducted. Findings support effectiveness of melatonin in improving sleep-onset difficulties and of meditative movement therapies for self-report sleep efficiency and severity of the insomnia disorder. Some support was observed for exercise, hypnotherapy, and transcranial magnetic resonance, but the number of studies for these interventions is still too small. None of the considered interventions received superior evidence to CBT-I, which should be more widely disseminated in primary care
Tilted Rotation and Wobbling Motion in Nuclei
The self-consistent harmonic oscillator model including the three-dimensional
cranking term is extended to describe collective excitations in the random
phase approximation. It is found that quadrupole collective excitations
associated with wobbling motion in rotating nuclei lead to the appearance of
two- or three-dimensional rotation.Comment: 9 pages, 2 Postscript figures, corrected typo
Fractional Dirac Bracket and Quantization for Constrained Systems
So far, it is not well known how to deal with dissipative systems. There are
many paths of investigation in the literature and none of them present a
systematic and general procedure to tackle the problem. On the other hand, it
is well known that the fractional formalism is a powerful alternative when
treating dissipative problems. In this paper we propose a detailed way of
attacking the issue using fractional calculus to construct an extension of the
Dirac brackets in order to carry out the quantization of nonconservative
theories through the standard canonical way. We believe that using the extended
Dirac bracket definition it will be possible to analyze more deeply gauge
theories starting with second-class systems.Comment: Revtex 4.1. 9 pages, two-column. Final version to appear in Physical
Review
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