2,150 research outputs found
Factors influencing convergence of a learning system
Measurement rays affecting algorithm for learning control syste
FIRREA and Federal Common Law: The Extent to Which They Preempt State Law Regarding the Duties and Standard of Liability Imposed upon Financial Institution Directors
FIRREA and Federal Common Law: The Extent to Which They Preempt State Law Regarding the Duties and Standard of Liability Imposed upon Financial Institution Directors
Solitons and Black Holes in a Generalized Skyrme Model with Dilaton-Quarkonium field
Skyrme theory is among the viable effective theories which emerge from
low-energy limit of quantum chromodynamics. Many of its generalizations include
also a dilaton. Here we find new self-gravitating solutions, both solitons and
black holes, in a Generalized Skyrme Model (GSM) in which a dilaton is present.
The investigation of the properties of the solutions is done numerically. We
find that the introduction of the dilaton in the theory does not change the
picture qualitatively, only quantitatively. The model considered here has one
free parameter more than the Einstein-Skyrme model which comes from the
potential of the dilaton. We have applied also the turning point method to
establish that one of the black-hole branches of solutions is unstable. The
turning point method here is based on the first law of black-hole
thermodynamics a detailed derivation of which is given in the Appendix of the
paper.Comment: 19 pages, 10 figures; v2: typos corrected, comments adde
Benchmark calculations for elastic fermion-dimer scattering
We present continuum and lattice calculations for elastic scattering between
a fermion and a bound dimer in the shallow binding limit. For the continuum
calculation we use the Skorniakov-Ter-Martirosian (STM) integral equation to
determine the scattering length and effective range parameter to high
precision. For the lattice calculation we use the finite-volume method of
L\"uscher. We take into account topological finite-volume corrections to the
dimer binding energy which depend on the momentum of the dimer. After
subtracting these effects, we find from the lattice calculation kappa a_fd =
1.174(9) and kappa r_fd = -0.029(13). These results agree well with the
continuum values kappa a_fd = 1.17907(1) and kappa r_fd = -0.0383(3) obtained
from the STM equation. We discuss applications to cold atomic Fermi gases,
deuteron-neutron scattering in the spin-quartet channel, and lattice
calculations of scattering for nuclei and hadronic molecules at finite volume.Comment: 16 pages, 5 figure
Molecular Imaging of Petroleum Asphaltenes by Scanning Tunneling Microscopy: Verification of Structure from 13C and Proton Nuclear Magnetic Resonance Data
Scanning tunneling microscopy (STM) was used to verify the molecular structure of Maya asphaltene which had been derived from combined 13C and proton nuclear magnetic resonance (NMR) experiments. Petroleum asphaltenes are known to contain large polynuclear aromatic centers with aliphatic sidechains. Average molecular models of Maya asphaltenes were derived using studies which included combined proton and 13C NMR data to determine total aromatic carbon content and the ratio of peripheral to internal aromatic ring carbons. These parameters permitted estimating the average number of aromatic rings per condensed cluster.
These Maya asphaltenes were imaged by scanning tunneling microscopy (STM) in a dilute solution of tetrahydrofuran on highly oriented pyrolytic graphite. The sizes and structures of the asphaltenes as observed by STM are in reasonable agreement with these average molecular models. We observed asymmetric structures whose largest dimension averaged 10.4 Å ± 1.9 Å from 24 separate images. The condensed ring portions of three representative NMR derived molecular models yielded an average dimension of 11.1 Å ± 1.4 Å
Determining the influence and effects of manufacturing variables on sulfur dioxide cells
A survey of the Li/SO2 manufacturing community was conducted to determine where variability exists in processing. The upper and lower limits of these processing variables might, by themselves or by interacting with other variables, influence safety, performance, and reliability. A number of important variables were identified and a comprehensive design experiment is being proposed to make the proper determinations
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