157,268 research outputs found
Analytical smoothing effect of solution for the boussinesq equations
In this paper, we study the analytical smoothing effect of Cauchy problem for
the incompressible Boussinesq equations. Precisely, we use the Fourier method
to prove that the Sobolev H 1-solution to the incompressible Boussinesq
equations in periodic domain is analytic for any positive time. So the
incompressible Boussinesq equation admet exactly same smoothing effect
properties of incompressible Navier-Stokes equations
Review of the "Bottom-Up" scenario
Thermalization of a longitudinally expanding color glass condensate with
Bjorken boost invariant geometry is investigated within parton cascade BAMPS.
Our main focus lies on the detailed comparison of thermalization, observed in
BAMPS with that suggested in the Bottom-Up scenario. We demonstrate that the
tremendous production of soft gluons via , which is shown in the
Bottom-Up picture as the dominant process during the early preequilibration,
will not occur in heavy ion collisions at RHIC and LHC energies, because the
back reaction hinders the absolute particle multiplication.
Moreover, contrary to the Bottom-Up scenario, soft and hard gluons thermalize
at the same time. The time scale of thermal equilibration in BAMPS calculations
is of order \as^{-2} (\ln \as)^{-2} Q_s^{-1}. After this time the gluon
system exhibits nearly hydrodynamic behavior. The shear viscosity to entropy
density ratio has a weak dependence on and lies close to the lower bound
of the AdS/CFT conjecture.Comment: Quark Matter 2008 Proceeding
Construction of optimal multi-level supersaturated designs
A supersaturated design is a design whose run size is not large enough for
estimating all the main effects. The goodness of multi-level supersaturated
designs can be judged by the generalized minimum aberration criterion proposed
by Xu and Wu [Ann. Statist. 29 (2001) 1066--1077]. A new lower bound is derived
and general construction methods are proposed for multi-level supersaturated
designs. Inspired by the Addelman--Kempthorne construction of orthogonal
arrays, several classes of optimal multi-level supersaturated designs are given
in explicit form: Columns are labeled with linear or quadratic polynomials and
rows are points over a finite field. Additive characters are used to study the
properties of resulting designs. Some small optimal supersaturated designs of
3, 4 and 5 levels are listed with their properties.Comment: Published at http://dx.doi.org/10.1214/009053605000000688 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Low-Voltage High-Linearity Wideband Current Differencing Transconductance Amplifier and Its Application on Current-Mode Active Filter
A low-voltage high-linearity wideband current differencing transconductance amplifier (CDTA) is presented in this paper. The CDTA consists of a current differencing circuit and a cross-coupling transconductance circuit. The PSPICE simulations of the proposed CDTA show a good performance: -3dB frequency bandwith is about 900 MHz, low power consumption is 2.48 mW, input current linear range is ±100 µA and low current-input resistance is less than 20 Ω, high current-output resistance is more than 3 MΩ. PSpice simulations for a current-mode universal filter and a proposed high-order filter are also conducted, and the results verify the validity of the proposed CDTA
Nuclear symmetry energy and core-crust transition in neutron stars: a critical study
The slope of the nuclear symmetry energy at saturation density is pointed
out as a crucial quantity to determine the mass and width of neutron-star
crusts. This letter clarifies the relation between and the core-crust
transition. We confirm that the transition density is soundly correlated with
despite differences between models, and we propose a clear understanding of
this correlation based on a generalised liquid drop model. Using a large number
of nuclear models, we evaluate the dispersion affecting the correlation between
the transition pressure and . From a detailed analysis it is shown
that this correlation is weak due to a cancellation between different terms.
The correlation between the isovector coefficients and plays
a crucial role in this discussion
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