40 research outputs found
Interaction of quasilocal harmonic modes and boson peak in glasses
The direct proportionality relation between the boson peak maximum in
glasses, , and the Ioffe-Regel crossover frequency for phonons,
, is established. For several investigated materials . At the frequency the mean free path of the
phonons becomes equal to their wavelength because of strong resonant
scattering on quasilocal harmonic oscillators. Above this frequency phonons
cease to exist. We prove that the established correlation between
and holds in the general case and is a direct consequence of
bilinear coupling of quasilocal oscillators with the strain field.Comment: RevTex, 4 pages, 1 figur
A new analysis of the short-duration, hard-spectrum GRB 051103, a possible extragalactic soft gamma repeater giant flare
On the Crustal Matter of Magnetars
We have investigated some of the properties of dense sub-nuclear matter at
the crustal region (both the outer crust and the inner crust region) of a
magnetar. The relativistic version of Thomas-Fermi (TF) model is used in
presence of strong quantizing magnetic field for the outer crust matter. The
compressed matter in the outer crust, which is a crystal of metallic iron, is
replaced by a regular array of spherically symmetric Wigner-Seitz (WS) cells.
In the inner crust region, a mixture of iron and heavier neutron rich nuclei
along with electrons and free neutrons has been considered. Conventional
Harrison-Wheeler (HW) and Bethe-Baym-Pethick (BBP) equation of states are used
for the nuclear mass formula. A lot of significant changes in the
characteristic properties of dense crustal matter, both at the outer crust and
the inner crust, have been observed.Comment: 29 pages REVTEX manuscript, 15 .eps figures (included
Handling conjunctions in named entities
Although the literature contains reports of very high accuracy figures for the recognition of named entities in text, there are still some named entity phenomena that remain problematic for existing text processing systems. One of these is the ambiguity of conjunctions in candidate named entity strings, an all-too-prevalent problem in corporate and legal documents. In this paper, we distinguish four uses of the conjunction in these strings, and explore the use of a supervised machine learning approach to conjunction disambiguation trained on a very limited set of ‘name internal’ features that avoids the need for expensive lexical or semantic resources. We achieve 84% correctly classified examples using k-fold evaluation on a data set of 600 instances. Further improvements are likely to require the use of wider domain knowledge and name external features.12 page(s