144 research outputs found
Two-Nucleon Scattering without partial waves using a momentum space Argonne V18 interaction
We test the operator form of the Fourier transform of the Argonne V18
potential by computing selected scattering observables and all Wolfenstein
parameters for a variety of energies. These are compared to the GW-DAC database
and to partial wave calculations. We represent the interaction and transition
operators as expansions in a spin-momentum basis. In this representation the
Lippmann-Schwinger equation becomes a six channel integral equation in two
variables. Our calculations use different numbers of spin-momentum basis
elements to represent the on- and off-shell transition operators. This is
because different numbers of independent spin-momentum basis elements are
required to expand the on- and off-shell transition operators. The choice of on
and off-shell spin-momentum basis elements is made so that the coefficients of
the on-shell spin-momentum basis vectors are simply related to the
corresponding off-shell coefficients.Comment: 14 pages, 8 Figures, typos correcte
An isospin dependent global nucleon-nucleus optical model at intermediate energies
A global nucleon-nucleus optical potential for elastic scattering has been
produced which replicates experimental data to high accuracy and compares well
with other recently formulated potentials. The calculation that has been
developed describes proton and neutron scattering from target nuclei ranging
from carbon to nickel and is applicable for projectile energies from 30 to 160
MeV. With these ranges it is suitable for calculations associated with
experiments performed by exotic beam accelerators. The potential is also
isospin dependent and has both real and imaginary isovector asymmetry terms to
better describe the dynamics of chains of isotopes and mirror nuclei. An
analysis of the validity and strength of the asymmetry term is included with
connections established to other optical potentials and charge-exchange
reaction data. An on-line observable calculator is available for this optical
potential.Comment: 31 pages, 21 figures, 4 tables; Accepted to Phys. Rev. C. This
version includes corrections to Eq. 1 and Table 1. Erratum sent to Phys. Rev.
Microscopic calculations of medium effects for 200-MeV (p,p') reactions
We examine the quality of a G-matrix calculation of the effective
nucleon-nucleon (NN) interaction for the prediction of the cross section and
analyzing power for 200-MeV (p,p') reactions that populate natural parity
states in O, Si, and Ca. This calculation is based on a
one-boson-exchange model of the free NN force that reproduces NN observables
well. The G-matrix includes the effects of Pauli blocking, nuclear binding, and
strong relativistic mean-field potentials. The implications of adjustments to
the effective mass ansatz to improve the quality of the approximation at
momenta above the Fermi level will be discussed, along with the general quality
of agreement to a variety of (p,p') transitions.Comment: 36 pages, TeX, 18 figure
Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing
No abstract available
High rate capabilities Fe3O4-based Cu nano-architectured electrodes for lithium-ion battery applications
All battery technologies are known to suffer from kinetic problems linked to the solid-state diffusion of Li in intercalation electrodes, the conductivity of the electrolyte in some cases and the quality of interfaces. For Li-ion technology the latter effect is especially acute when conversion rather than intercalation electrodes are used. Nano-architectured electrodes are usually suggested to enhance kinetics, although their realization is cumbersome. To tackle this issue for the conversion electrode material Fe3O4, we have used a two-step electrode design consisting of the electrochemically assisted template growth of Cu nanorods onto a current collector followed by electrochemical plating of Fe3O4. Using such electrodes, we demonstrate a factor of six improvement in power density over planar electrodes while maintaining the same total discharge time. The capacity at the 8C rate was 80% of the total capacity and was sustained over 100 cycles. The origin of the large hysteresis between charge and discharge, intrinsic to conversion reactions, is discussed and approaches to reduce it are proposed. We hope that such findings will help pave the way for the use of conversion reaction electrodes in future-generation Li-ion batteries
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