18,421 research outputs found
Global Classical and Weak Solutions to the Three-Dimensional Full Compressible Navier-Stokes System with Vacuum and Large Oscillations
We establish the global existence and uniqueness of classical solutions to
the three-dimensional full compressible Navier-Stokes system with smooth
initial data which are of small energy but possibly large oscillations where
the initial density is allowed to vanish. Moreover, for the initial data which
may be discontinuous and contain vacuum states, we also obtain the global
existence of weak solutions. These results generalize previous ones on
classical and weak solutions for initial density being strictly away from
vacuum, and are the first for global classical and weak solutions which may
have large oscillations and can contain vacuum states.Comment: 61 page
Existence and Blowup Behavior of Global Strong Solutions to the Two-Dimensional Baratropic Compressible Navier-Stokes System with Vacuum and Large Initial Data
For periodic initial data with initial density allowed to vanish, we
establish the global existence of strong and weak solutions for the
two-dimensional compressible Navier-Stokes equations with no restrictions on
the size of initial data provided the bulk viscosity coefficient is with . These results generalize and improve the
previous ones due to Vaigant-Kazhikhov([Sib. Math. J. (1995), 36(6),
1283-1316]) which requires . Moreover, both the uniform upper bound of
the density and the large-time behavior of the strong and weak solutions are
also obtained.Comment: 31 page
Serrin Type Criterion for the Three-Dimensional Viscous Compressible Flows
We extend the well-known Serrin's blowup criterion for the three-dimensional
(3D) incompressible Navier-Stokes equations to the 3D viscous compressible
cases. It is shown that for the Cauchy problem of the 3D compressible
Navier-Stokes system in the whole space, the strong or smooth solution exists
globally if the velocity satisfies the Serrin's condition and either the
supernorm of the density or the -norm of the divergence of
the velocity is bounded. Furthermore, in the case that either the shear
viscosity coefficient is suitably large or there is no vacuum, the Serrin's
condition on the velocity can be removed in this criteria.Comment: 16 page
Oblique Hanle Effect in Semiconductor Spin Transport Devices
Spin precession and dephasing ("Hanle effect") provides an unambiguous means
to establish the presence of spin transport in semiconductors. We compare
theoretical modeling with experimental data from drift-dominated silicon
spin-transport devices, illustrating the non-trivial consequences of employing
oblique magnetic fields (due to misalignment or intentional, fixed in-plane
field components) to measure the effects of spin precession. Model results are
also calculated for Hanle measurements under conditions of diffusion-dominated
transport, revealing an expected Hanle peak-widening effect induced by the
presence of fixed in-plane magnetic bias fields
Global Well-Posedness of Classical Solutions with Large Oscillations and Vacuum to the Three-Dimensional Isentropic Compressible Navier-Stokes Equations
We establish the global existence and uniqueness of classical solutions to
the Cauchy problem for the isentropic compressible Navier-Stokes equations in
three spatial dimensions with smooth initial data which are of small energy but
possibly large oscillations with constant state as far field which could be
either vacuum or non-vacuum. The initial density is allowed to vanish and the
spatial measure of the set of vacuum can be arbitrarily large, in particular,
the initial density can even have compact support. These results generalize
previous results on classical solutions for initial densities being strictly
away from vacuum, and are the first for global classical solutions which may
have large oscillations and can contain vacuum states.Comment: 30 page
On a Variant of the Elliott-Halberstam Conjecture and the Goldbach Conjecture
In this paper we prove that the binary Goldbach conjecture for sufficiently
large even integers would follow under the assumptions of both the
Elliott-Halberstam conjecture and a variant of the Elliott-Halberstam
conjecture twisted by the M\"{o}bius function, provided that the sum of their
level of distributions exceeds 1. This continues the work of Pan. An analogous
result for the twin prime conjecture is obtained by Ram Murty and Vatwani
- …