4,294 research outputs found
Magnetic Properties of Dilute Alloys: Equations for Magnetization and its Structural Fluctuations
The dilute Heisenberg ferromagnet is studied taking into account fluctuations
of magnetization caused by disorder. A self-consistent system of equations for
magnetization and its mean quadratic fluctuations is derived within the
configurationally averaged two-time temperature Green's function method. This
system of equations is analised at low concentration of non-magnetic
impurities. Mean relative quadratic fluctuations of magnetization are revealed
to be proportional to the square of concentration of impurities.Comment: 16 pages, LaTe
Relativistic Green's function approach to charged-current neutrino-nucleus quasielastic scattering
A relativistic Green's function approach to inclusive quasielastic
charged-current neutrino-nucleus scattering is developed. The components of the
hadron tensor are written in terms of the single-particle Green's function,
which is expanded on the eigenfunctions of the nuclear optical potential, so
that final state interactions are accounted for by means of a complex optical
potential but without a loss of flux. Results for the (neutrino_mu, mu-)
reaction on 16O and 12C target nuclei are presented and discussed. A reasonable
agreement of the flux-averaged cross section on 12C with experimental data is
achieved.Comment: 7 pages, 4 figure
The exporting and subcontracting decisions of Viet Nam\u27s small- and medium-sized enterprises
The exporting and subcontracting decisions of a panel of Vietnamese private small- and medium-sized enterprises is investigated. We find that among subcontractors, subcontracting is a supplementary rather than primary activity; the propensity to export increases with managers\u27 or owners\u27 knowledge of customs law; and, there is some evidence that subcontractors are more likely to have made product improvements while exporters are more likely to have adopted new processes or technologies. Our study provides useful insights into SME exporting and subcontracting strategies made more relevant by the expected reductions in trade costs associated with the World Trade Organization\u27s Trade Facilitation Agreement
Facile synthesis of reduced graphene oxide/MWNTs nanocomposite supercapacitor materials tested as electrophoretically deposited films on glassy carbon electrodes
This paper reports on a facile synthesis method for reduced graphene oxide (rGO)/multi-walled carbon nanotubes (MWNTs) nanocomposites. The initial step involves the use of graphene oxide to disperse the MWNTs, with subsequent reduction of the resultant graphene oxide/MWNTs composites using l-ascorbic acid (LAA) as a mild reductant. Reduction by LAA preserves the interaction between the rGO sheets and MWNTs. The dispersion-containing rGO/MWNTs composites was characterized and electrophoretically deposited anodically onto glassy carbon electrodes to form high surface area films for capacitance testing. Pseudo capacitance peaks were observed in the rGO/MWNTs composite electrodes, resulting in superior performance with capacitance values up to 134.3 F g−1 recorded. This capacitance value is higher than those observed for LAA-reduced GO (LAA-rGO) (63.5 F g−1), electrochemically reduced GO (EC-rGO) (27.6 F g−1), or electrochemically reduced GO/MWNTs (EC-rGO/MWNTs) (98.4 F g−1)-based electrodes.© 2013, Springer Science+Business Media Dordrecht
Coulomb Distortion in Quasielastic Scattering on Nuclei: Effective Momentum Approximation and Beyond
The role of the effective momentum approximation to disentangle Coulomb
distortion effects in quasielastic reactions is investigated. The
separation of the cross section in longitudinal and transverse components is
discussed including higher order DWBA corrections due to the focusing of the
electron waves.The experimental studies performed, in the last few years,
making use of different approximate treatments are shown to be sometime
inconsistent. As a consequence some of the longitudinal and transverse
responses, extracted from the inclusive cross sections cannot be considered
reliable. A separation procedure based on the effective momentum approximation
is discussed in connection with the recent experimental data on
electron/positron quasielastic scattering on C and Pb.Comment: latex, no figures, submitted to Nucl. Phys.
Neutrino-nucleus quasi-elastic scattering and strange quark effects
A relativistic distorted-wave impulse-approximation model is applied to
quasi-elastic neutrino-nucleus scattering. The bound state is obtained in the
framework of the relativistic mean field theory and the final state interaction
is taken into account in the scattering state. Results for the charged- and
neutral-current neutrino (antineutrino) reactions on C target nucleus
are presented and the sensitivity of various quantities to the strange quark
content of the nucleon weak current is discussed.Comment: 18 pages, 10 figure
Biodesign Exhibition Catalog
Catalogue created on the occasion of Biodesign: From Inspiration to Integration, August 24 to September 27, 2018, an exhibition organized as part of RISD Nature Lab’s 80th anniversary celebrations at the Woods-Gerry Gallery, Providence, Rhode Island. Curated by William Myers, Lucia Monge, David Kim, Neal Overstrom, Julia van den Hout, and Peter Rogers
Neutrino nucleus cross sections for low energy neutrinos at SNS facilities
We calculate the neutrino nucleus cross sections for charged lepton
production relevant for the experiments proposed with the stopped muon
neutrinos using neutron spallation source facility. The calculations are done
in local density approximation taking into account Pauli blocking, Fermi motion
effects and renormalization of weak transition strengths in the nuclear medium.
The effect of Coulomb distortion of the lepton produced in charge current
reactions is taken into account by using the Fermi function as well as in a
model where an effective momentum has been used for the lepton moving in the
local Coulomb field of the final nucleus. The numerical results for the
neutrino nucleus total cross sections averaged over Michel spectrum are
presented for various nuclei.Comment: 16pages, 9figures, Submitted to Nucl. Phys.
Effective Action and Schwinger Pair Production in Scalar QED
Some astrophysical objects are supposed to have very strong electromagnetic
fields above the critical strength. Quantum fluctuations due to strong
electromagnetic fields modify the Maxwell theory and particularly electric
fields make the vacuum unstable against pair production of charged particles.
We study the strong field effect such as the effective action and the Schwinger
pair production in scalar QED.Comment: RevTex 6 pages, no figure; Proceedings of APCTP Winter School on
Black Hole Astrophysics 2008, Jan 24-29, 200
The Role of Final State Interactions in Quasielastic Fe Reactions at large
A relativistic finite nucleus calculation using a Dirac optical potential is
used to investigate the importance of final state interactions [FSI] at large
momentum transfers in inclusive quasielastic electronuclear reactions. The
optical potential is derived from first-order multiple scattering theory and
then is used to calculate the FSI in a nonspectral Green's function doorway
approach. At intermediate momentum transfers excellent predictions of the
quasielastic Fe experimental data for the longitudinal response
function are obtained. In comparisons with recent measurements at ~GeV/c the theoretical calculations of give good agreement for
the quasielastic peak shape and amplitude, but place the position of the peak
at an energy transfer of about ~MeV higher than the data.Comment: 13 pages typeset using revtex 3.0 with 6 postscript figures in
accompanying uuencoded file; submitted to Phys. Rev.
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