1,921 research outputs found
Bounce-free spherical hydrodynamic implosion
In a bounce-free spherical hydrodynamic implosion, the post-stagnation hot
core plasma does not expand against the imploding flow. Such an implosion
scheme has the advantage of improving the dwell time of the burning fuel,
resulting in a higher fusion burn-up fraction. The existence of bounce-free
spherical implosions is demonstrated by explicitly constructing a family of
self-similar solutions to the spherically symmetric ideal hydrodynamic
equations. When applied to a specific example of plasma liner driven
magneto-inertial fusion, the bounce-free solution is found to produce at least
a factor of four improvement in dwell time and fusion energy gain.Comment: accepted by Phys. Plasmas (Nov. 7, 2011); for Ref. 11, please see
ftp://ftp.lanl.gov/public/kagan/liner_evolution.gi
Symmetries and Lie algebra of the differential-difference Kadomstev-Petviashvili hierarchy
By introducing suitable non-isospectral flows we construct two sets of
symmetries for the isospectral differential-difference Kadomstev-Petviashvili
hierarchy. The symmetries form an infinite dimensional Lie algebra.Comment: 9 page
Molecular cloning of a novel GSK3/shaggy-like gene from Triticum monococcum L. and its expression in response to salt, drought and other abiotic stresses
The glycogen synthase kinase 3 (GSK3)/SHAGGY-like kinases are nonreceptor serine/threonine protein kinases that are involved in a variety of biological processes. Here, a novel GSK-3-like kinase encoding cDNA was isolated from Triticum monococcum L. seedlings by reverse transcriptase polymerase chain reaction (RT-PCR). Sequence analysis showed that the full length of cDNA consist of 1,543 bp with an open reading frame of 1,068 bp, which encodes 355 amino acid residues. The deduced amino acid sequence showed a high homology with shaggy-like kinases from Triticum aestivum, Zea mays, Trifolium repens, Nicotine tabacum, Medicago sativa and Arabidopsis thaliana; therefore, the gene was named TmGSK1 (Triticum monococcum Glycogen Synthase Kinase 1,GenBank Accession No. DQ443471). Southern blot analysis indicated that there was only one copy of TmGSK1 in the einkorn wheat genome. Quantitative real-time RT-PCR studies showed that the expression of TmGSK1 in the einkorn wheat was induced by salt stress, mechanical wounding, ABA hormone, cold and drought. These results suggest that cells accumulate more TmGSK1 mRNA response to those abiotic stresses. TmGSK1 was shown to be a positive regulator commonly involved in the tolerance to salt, mechanical injury, ABA hormone, cold and drought in einkorn wheat.Key words: TmGSK1, abiotic stress, shaggy-like kinase, signal transduction, Triticum monococcum L
Hybrid exciton-polaritons in a bad microcavity containing the organic and inorganic quantum wells
We study the hybrid exciton-polaritons in a bad microcavity containing the
organic and inorganic quantum wells. The corresponding polariton states are
given. The analytical solution and the numerical result of the stationary
spectrum for the cavity field are finishedComment: 3 pages, 1 figure. appear in Communications in Theoretical Physic
Density matrix renormalisation group study of the correlation function of the bilinear-biquadratic spin-1 chain
Using the recently developed density matrix renormalization group approach,
we study the correlation function of the spin-1 chain with quadratic and
biquadratic interactions. This allows us to define and calculate the
periodicity of the ground state which differs markedly from that in the
classical analogue. Combining our results with other studies, we predict three
phases in the region where the quadratic and biquadratic terms are both
positive.Comment: 13 pages, Standard Latex File + 5 PostScript figures in separate (New
version with SUBSTANTIAL REVISIONS to appear in J Phys A
Search for the Nondimerized Quantum Nematic Phase in the Spin-1 Chain
Chubukov's proposal concerning the possibility of a nondimerized quantum
nematic phase in the ground-state phase diagram of the bilinear-biquadratic
spin-1 chain is studied numerically. Our results do not support the existence
of this phase, but they rather indicate a direct transition from the
ferromagnetic into the dimerized phase.Comment: REVTEX, 14 pages +8 PostScript figure
Shear viscosity, instability and the upper bound of the Gauss-Bonnet coupling constant
We compute the dimensionality dependence of for charged black branes
with Gauss-Bonnet correction. We find that both causality and stability
constrain the value of Gauss-Bonnet coupling constant to be bounded by 1/4 in
the infinite dimensionality limit. We further show that higher dimensionality
stabilize the gravitational perturbation. The stabilization of the perturbation
in higher dimensional space-time is a straightforward consequence of the
Gauss-Bonnet coupling constant bound.Comment: 16 pages,3 figures+3 tables,typos corrected, published versio
An extension of the coupled-cluster method: A variational formalism
A general quantum many-body theory in configuration space is developed by
extending the traditional coupled cluter method (CCM) to a variational
formalism. Two independent sets of distribution functions are introduced to
evaluate the Hamiltonian expectation. An algebraic technique for calculating
these distribution functions via two self-consistent sets of equations is
given. By comparing with the traditional CCM and with Arponen's extension, it
is shown that the former is equivalent to a linear approximation to one set of
distribution functions and the later is equivalent to a random-phase
approximation to it. In additional to these two approximations, other
higher-order approximation schemes within the new formalism are also discussed.
As a demonstration, we apply this technique to a quantum antiferromagnetic spin
model.Comment: 15 pages. Submitted to Phys. Rev.
Quantum size effects on the perpendicular upper critical field in ultra-thin lead films
We report the thickness-dependent (in terms of atomic layers) oscillation
behavior of the perpendicular upper critical field in the
ultra-thin lead films at the reduced temperature (). Distinct
oscillations of the normal-state resistivity as a function of film thickness
have also been observed. Compared with the oscillation, the
shows a considerable large oscillation amplitude and a phase shift. The
oscillatory mean free path caused by quantum size effect plays a role in
oscillation.Comment: 4 pages, 4 figure
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