148,851 research outputs found
Algebraic orbifold conformal field theories
We formulate the unitary rational orbifold conformal field theories in the
algebraic quantum field theory framework. Under general conditions, we show
that the orbifold of a given unitary rational conformal field theories
generates a unitary modular category. Many new unitary modular categories are
obtained. We also show that the irreducible representations of orbifolds of
rank one lattice vertex operator algebras give rise to unitary modular
categories and determine the corresponding modular matrices, which has been
conjectured for some time.Comment: 24 pages, Amste
Electrospinning of poly(ethylene-co-vinyl alcohol) nanofibres encapsulated with Ag nanoparticles for skin wound healing
Copyright © 2011 Chao Xu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Skin wound healing is an urgent problem in clinics and military activities. Although significant advances have been made in its treatment, there are several challenges associated with traditional methods, for example, limited donor skin tissue for transplantation and inflammation during long-term healing time. To address these challenges, in this study we present a method to fabricate Poly(ethylene-co-vinyl alcohol) (EVOH) nanofibres encapsulated with Ag nanoparticle using electrospinning technique. The fibres were fabricated with controlled diameters (59nm-3m) by regulating three main parameters, that is, EVOH solution concentration, the electric voltage, and the distance between the injection needle tip (high-voltage point) and the fibre collector. Ag was added to the nanofibres to offer long-term anti-inflammation effect by slow release of Ag nanoparticles through gradual degradation of EVOH nanofibre. The method developed here could lead to new dressing materials for treatment of skin wounds. © 2011 Chao Xu et al.The work was partially supported by the National Natural Science Foundation of China (nos. 10825210, 10872157, and 31050110125) and the National 111 Project of China (no. B06024)
Gluonic probe for the short range correlation in nucleus
We investigate the gluonic probe to the nucleon-nucleon short range correlation (SRC) in nucleus through heavy flavor production in deep inelastic scattering (DIS). The relevant EMC effects of [Formula presented] structure function will provide a universality test of the SRCs which have been extensively studied in the quark-channel. These SRCs can also be studied through the sub-threshold production of heavy flavor in eA collisions at the intermediate energy electron-ion collider, including open Charm and J/ψ (ϒ) production
A new three-parameter correlation for gamma-ray bursts with a plateau phase in the afterglow
Gamma ray bursts (GRBs) have great advantages for their huge burst energies,
luminosities and high redshifts in probing the Universe. A few interesting
luminosity correlations of GRBs have been used to test cosmology models.
Especially, for a subsample of long GRBs with known redshifts and a plateau
phase in the afterglow, a correlation between the end time of the plateau phase
(in the GRB rest frame) and the corresponding X-ray luminosity has been found.
In this paper, we re-analyze the subsample and found that a significantly
tighter correlation exists when we add a third parameter, i.e. the isotropic
-ray energy release, into the consideration. Additionally, both long
and intermediate duration GRBs are consistent with the same three-parameter
correlation equation. It is argued that the new three-parameter correlation is
consistent with the hypothesis that the subsample of GRBs with a plateau phase
in the afterglow be associated with the birth of rapidly rotating magnetars,
and that the plateau be due to the continuous energy-injection from the
magnetar. It is suggested that the newly born millisecond magnetars associated
with GRBs might provide a good standard candle in the Universe.Comment: 11 pages, 3 figures, 1 table; A&A, in pres
Ultra High Energy Cosmic Rays: Strangelets? -- Extra dimensions, TeV-scale black holes and strange matter
The conjecture that ultra high energy cosmic rays (UHECRs) are actually
strangelets is discussed. Besides the reason that strangelets can do as cosmic
rays beyond the GZK-cutoff, another argument to support the conjecture is
addressed in this letter via the study of formation of TeV-scale microscopic
black holes when UHECRs bombarding bare strange stars. It is proposed that the
exotic quark surface of a bare strange star could be an effective
astro-laboratory in the investigations of the extra dimensions and of the
detection of ultra-high energy neutrino fluxes. The flux of neutrinos (and
other point-like particles) with energy >2.3 x 10^{20} eV could be expected to
be smaller than 10^{-26} cm^{-2}$ s^{-1} if there are two extra spatial
dimensions.Comment: accepted by Chin. Phys. Lett., or at
http://vega.bac.pku.edu.cn/~rxxu/publications/index_P.ht
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
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
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