548 research outputs found
REMOVED: Reverse Solute Diffusion and its Adverse Effect on Osmotic Power Production in Pressure Retarded Osmosis
This article has been removed: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy).This article has been removed at the request of the Executive Publisher.This article has been removed because it was published without the permission of the author(s)
Magnetic moment of hyperons in nuclear matter by using quark-meson coupling models
We calculate the magnetic moments of hyperons in dense nuclear matter by
using relativistic quark models. Hyperons are treated as MIT bags, and the
interactions are considered to be mediated by the exchange of scalar and vector
mesons which are approximated as mean fields. Model dependence is investigated
by using the quark-meson coupling model and the modified quark-meson coupling
model; in the former the bag constant is independent of density and in the
latter it depends on density. Both models give us the magnitudes of the
magnetic moments increasing with density for most octet baryons. But there is a
considerable model dependence in the values of the magnetic moments in dense
medium. The magnetic moments at the nuclear saturation density calculated by
the quark meson coupling model are only a few percents larger than those in
free space, but the magnetic moments from the modified quark meson coupling
model increase more than 10% for most hyperons. The correlations between the
bag radius of hyperons and the magnetic moments of hyperons in dense matter are
discussed.Comment: substantial changes in the text, submitted to PL
Direct patterning of periodic semiconductor nanostructures using single-pulse nanosecond laser interference
We demonstrate an effective method for fabricating large area periodic two-dimensional
semiconductor nanostructures by means of single-pulse laser interference. Utilizing a pulsed
nanosecond laser with a wavelength of 355 nm, precisely ordered square arrays of nanoholes
with a periodicity of 300 nm were successfully obtained on UV photoresist and also directly
via a resist-free process onto semiconductor wafers. We show improved uniformity using a
beam-shaping system consisting of cylindrical lenses with which we can demonstrate highly
regular arrays over hundreds of square micrometers. We propose that our novel observation of
direct pattern transfer to GaAs is due to local congruent evaporation and subsequent droplet
etching of the surface. The results show that single-pulse interference can provide a rapid and
highly efficient route for the realization of wide-area periodic nanostructures on semiconductors
and potentially on other engineering materials
Improved Eavesdropping Detection Strategy in Quantum Direct Communication Protocol Based on Four-particle GHZ State
In order to improve the eavesdropping detection efficiency in two-step
quantum direct communication protocol, an improved eavesdropping detection
strategy using four-particle GHZ state is proposed, in which four-particle GHZ
state is used to detect eavesdroppers. During the security analysis, the method
of the entropy theory is introduced, and two detection strategies are compared
quantitatively by using the constraint between the information which
eavesdropper can obtain and the interference introduced. If the eavesdroppers
intend to obtain all information, the eavesdropping detection rate of the
original two-step quantum direct communication protocol by using EPR pair block
as detection particles is 50%; while the proposed strategy's detection rate is
88%. In the end, the security of the proposed protocol is discussed. The
analysis results show that the eavesdropping detection strategy presented is
more secure.Comment: 14 pages, 3 figures. arXiv admin note: substantial text overlap with
arXiv:quant-ph/0308173 by different author
A Measurement of Psi(2S) Resonance Parameters
Cross sections for e+e- to hadons, pi+pi- J/Psi, and mu+mu- have been
measured in the vicinity of the Psi(2S) resonance using the BESII detector
operated at the BEPC. The Psi(2S) total width; partial widths to hadrons,
pi+pi- J/Psi, muons; and corresponding branching fractions have been determined
to be Gamma(total)= (264+-27) keV; Gamma(hadron)= (258+-26) keV, Gamma(mu)=
(2.44+-0.21) keV, and Gamma(pi+pi- J/Psi)= (85+-8.7) keV; and Br(hadron)=
(97.79+-0.15)%, Br(pi+pi- J/Psi)= (32+-1.4)%, Br(mu)= (0.93+-0.08)%,
respectively.Comment: 8 pages, 6 figure
A sex-specific role for androgens in angiogenesis
Mounting evidence suggests that in men, serum levels of testosterone are negatively correlated to cardiovascular and all-cause mortality. We studied the role of androgens in angiogenesis, a process critical in cardiovascular repair/regeneration, in males and females. Androgen exposure augmented key angiogenic events in vitro. Strikingly, this occurred in male but not female endothelial cells (ECs). Androgen receptor (AR) antagonism or gene knockdown abrogated these effects in male ECs. Overexpression of AR in female ECs conferred androgen sensitivity with respect to angiogenesis. In vivo, castration dramatically reduced neovascularization of Matrigel plugs. Androgen treatment fully reversed this effect in male mice but had no effect in female mice. Furthermore, orchidectomy impaired blood-flow recovery from hindlimb ischemia, a finding rescued by androgen treatment. Our findings suggest that endogenous androgens modulate angiogenesis in a sex-dependent manner, with implications for the role of androgen replacement in men
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