15,563 research outputs found
Modelling CC neutrino cross sections in the few GeV energy region
Selected problems in modelling neutrino-nucleon and -nuclei cross sections in
the neutrino energy region of the few GeV are reviewed.Comment: Presented by J.T. Sobczyk at the Cracow Epiphany Conference on
Neutrinos and Dark Matter, Jan. 5-8, 2006, Cracow, Polan
The U(1) Problem in Chiral Random Matrix Models
We show that conventional asymmetric chiral random matrix models (ChRMM),
with a gaussian distribution in the asymmetry, provide for a screening of the
topological charge and a resolution of the problem in the unquenched
approximation. Our exact results to order are in agreement with numerical
estimates using large ensembles of asymmetric ChRMM with gaussian
distributions.Comment: ReVTaeX, 9 pages with 2 EPS figures. Uses the feynmf package version
1.0 for Feynman graph
Wroclaw neutrino event generator
A neutrino event generator developed by the Wroclaw Neutrino Group is
described. The physical models included in the generator are discussed and
illustrated with the results of simulations. The considered processes are
quasi-elastic scattering and pion production modelled by combining the
resonance excitation and deep inelastic scattering.Comment: Talk given at 2nd Scandanavian Neutrino Workshop (SNOW 2006),
Stockholm, Sweden, 2-6 May 2006. 3 pages, 6 figure
On the wake of a Darrieus turbine
The theory and experimental measurements on the aerodynamic decay of a wake from high performance vertical axis wind turbine are discussed. In the initial experimental study, the wake downstream of a model Darrieus rotor, 28 cm diameter and a height of 45.5 cm, was measured in a Boundary Layer Wind Tunnel. The wind turbine was run at the design tip speed ratio of 5.5. It was found that the wake decayed at a slower rate with distance downstream of the turbine, than a wake from a screen with similar troposkein shape and drag force characteristics as the Darrieus rotor. The initial wind tunnel results indicated that the vertical axis wind turbines should be spaced at least forty diameters apart to avoid mutual power depreciation greater than ten per cent
Aggregates of rod-coil diblock copolymers adsorbed at a surface
The behaviour of rod-coil diblock copolymers close to a surface is discussed
by using extended scaling methods. The copolymers are immersed in selective
solvent such that the rods are likely to aggregate to gain energy. The rods are
assumed to align only parallel to each other, such that they gain a maximum
energy by forming liquid crystalline structures. If an aggregate of these
copolymers adsorbs with the rods parallel to the surface the rods shift with
respect to each other to allow for the chains to gain entropy. It is shown that
this shift decays with increasing distance from the surface. The profile of
this decay away from the surface is calculated by minimisation of the total
free energy of the system. The stability of such an adsorbed aggregate and
other possible configurations are discussed as well.Comment: 10 pages, 11 figure
Domain Dynamics of Magnetic Films with Perpendicular Anisotropy
We study the magnetic properties of nanoscale magnetic films with large
perpendicular anisotropy comparing polarization microscopy measurements on
Co_28Pt_72 alloy samples based on the magneto-optical Kerr effect with Monte
Carlo simulations of a corresponding micromagnetic model. We focus on the
understanding of the dynamics especially the temperature and field dependence
of the magnetisation reversal process. The experimental and simulational
results for hysteresis, the reversal mechanism, domain configurations during
the reversal, and the time dependence of the magnetisation are in very good
qualitative agreement. The results for the field and temperature dependence of
the domain wall velocity suggest that for thin films the hysteresis can be
described as a depinning transition of the domain walls rounded by thermal
activation for finite temperatures.Comment: 7 pages Latex, Postscript figures included, accepted for publication
in Phys.Rev.B, also availible at:
http://www.thp.Uni-Duisburg.DE/Publikationen/Publist_Us_R.htm
A Failure of Communication: An Argument for the Closing of the NYSE Floor
Part I of this Note describes and analyzes the stock exchange communication process as it has existed in the past and as it currently exists, paying particular attention to the role of the floor broker and the stock specialist.\u27 Part II examines certain alternatives, evaluating such systems as to their potential as a replacement for the physical exchanges. Part III suggests an SEC rule granting specific exemption from exchange reporting requirements to low-volume automated systems in the hope of spurring innovation in the business of trading securities
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