7,123 research outputs found
Is the Coulomb sum rule violated in nuclei?
Guided by the experimental confirmation of the validity of the Effective
Momentum Approximation (EMA) in quasi-elastic scattering off nuclei, we have
re-examined the extraction of the longitudinal and transverse response
functions in medium-weight and heavy nuclei. In the EMA we have performed a
Rosenbluth separation of the available world data on Ca, Ca,
Fe, Au, Pb and U. We find that the longitudinal
response function for these nuclei is "quenched" and that the Coulomb sum is
not saturated, at odds with claims in the literature.Comment: 10 pages, 6 figure
Video distribution system cost model
A cost model that can be used to systematically identify the costs of procuring and operating satellite linked communications systems is described. The user defines a network configuration by specifying the location of each participating site, the interconnection requirements, and the transmission paths available for the uplink (studio to satellite), downlink (satellite to audience), and voice talkback (between audience and studio) segments of the network. The model uses this information to calculate the least expensive signal distribution path for each participating site. Cost estimates are broken downy by capital, installation, lease, operations and maintenance. The design of the model permits flexibility in specifying network and cost structure
Diffractive wave guiding of hot electrons by the Au (111) herringbone reconstruction
The surface potential of the herringbone reconstruction on Au(111) is known
to guide surface-state electrons along the potential channels. Surprisingly, we
find by scanning tunneling spectroscopy that hot electrons with kinetic
energies twenty times larger than the potential amplitude (38 meV) are still
guided. The efficiency even increases with kinetic energy, which is reproduced
by a tight binding calculation taking the known reconstruction potential and
strain into account. The guiding is explained by diffraction at the
inhomogeneous electrostatic potential and strain distribution provided by the
reconstruction.Comment: 10 pages, 9 figure
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