28,335 research outputs found
Curable polyphosphazenes
Class of polyphosphazene polymers can be cured at moderate temperatures by action of moisture. In addition, polymers maintain flexibility when exposed to low temperatures
Reversal of the extraordinary Hall effect polarity in thin Co/Pd multilayers
Thin Co/Pd multilayers, with room temperature perpendicular anisotropy and an
enhanced surface scattering, were studied for the possible use in the
extraordinary Hall effect (EHE) - based magnetic memory devices. Polarity of
the EHE signal was found to change from negative in thick samples to positive
in thin ones. Reversal of EHE sign was also observed in thick samples with
aging. The effect is argued to be related to the dominance of surface
scattering having the EHE polarity opposite to that of the bulk
Recovery of “Intrinsic Value” Damages in Case of Negligently Killed Pet Dog
The North Carolina Court of Appeals, in a case where negligent killing of a pet dog with no market value was admitted, has denied recovery of “intrinsic” damages (also called “actual” damages). Shera v. NC State University Veterinary Teaching Hospital, 723 S.E.2d 352 (N.C. App. 2012). Because the holding is narrow and the type of damages denied are not the same as emotional damages, a close look at the decision is warranted
Inhomogeneity and transverse voltage in superconductors
Voltages parallel and transverse to electric current in slightly
inhomogeneous superconductors can contain components proportional to the field
and temperature derivatives of the longitudinal and Hall resistivities. We show
that these anomalous contributions can be the origin of the zero field and
even-in-field transverse voltage occasionally observed at the superconductor to
normal state transition. The same mechanism can also cause an anomaly in the
odd-in-field transverse voltage interfering the Hall effect signal.Comment: 6 pages, 7 figure
He Scattering from Compact Clusters and from Diffusion-Limited Aggregates on Surfaces: Observable Signatures of Structure
The angular intensity distribution of He beams scattered from compact
clusters and from diffusion limited aggregates, epitaxially grown on metal
surfaces, is investigated theoretically. The purpose is twofold: to distinguish
compact cluster structures from diffusion limited aggregates, and to find
observable {\em signatures} that can characterize the compact clusters at the
atomic level of detail. To simplify the collision dynamics, the study is
carried out in the framework of the sudden approximation, which assumes that
momentum changes perpendicular to the surface are large compared with momentum
transfer due to surface corrugation. The diffusion limited aggregates on which
the scattering calculations were done, were generated by kinetic Monte Carlo
simulations. It is demonstrated, by focusing on the example of compact Pt
Heptamers, that signatures of structure of compact clusters may indeed be
extracted from the scattering distribution. These signatures enable both an
experimental distinction between diffusion limited aggregates and compact
clusters, and a determination of the cluster structure. The characteristics
comprising the signatures are, to varying degrees, the Rainbow, Fraunhofer,
specular and constructive interference peaks, all seen in the intensity
distribution. It is also shown, how the distribution of adsorbate heights above
the metal surface can be obtained by an analysis of the specular peak
attenuation. The results contribute to establishing He scattering as a powerful
tool in the investigation of surface disorder and epitaxial growth on surfaces,
alongside with STM.Comment: 41 pages, 16 postscript figures. For more details see
http://www.fh.huji.ac.il/~dan
Mixing and merging for spoken document retrieval
This paper describes a number of experiments that explo-
red the issues surrounding the retrieval of spoken documents. Two such
issues were examined. First, attempting to find the best use of speech
recogniser output to produce the highest retrieval effectiveness. Second,
investigating the potential problems of retrieving from a so-called "mi-
xed collection", i.e. one that contains documents from both a speech
recognition system (producing many errors) and from hand transcription (producing presumably near perfect documents). The result of the
first part of the work found that merging the transcripts of multiple
recognisers showed most promise. The investigation in the second part
showed how the term weighting scheme used in a retrieval system was
important in determining whether the system was affected detrimentally
when retrieving from a mixed collection
The Weyl-Lanczos Equations and the Lanczos Wave Equation in 4 Dimensions as Systems in Involution
Using the work by Bampi and Caviglia, we write the Weyl-Lanczos equations as
an exterior differential system. Using Janet-Riquier theory, we compute the
Cartan characters for all spacetimes with a diagonal metric and for the plane
wave spacetime since all spacetimes have a plane wave limit. We write the
Lanczos wave equation as an exterior differential system and, with assistance
from Janet-Riquier theory, we find that it forms a system in involution. This
result can be derived from the scalar wave equation itself. We compute its
Cartan characters and compare them with those of the Weyl-Lanczos equations.Comment: 18 pages, latex, no figures, references correcte
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