1,047,974 research outputs found
A Virtual Observatory Vision based on Publishing and Virtual Data
We would like to propose a vision of the Virtual Observatory where the "killer-app" is seen to be
generalizing and extending the idea of "publication" from the narrow meaning of peer-reviewed
journals. Here, publication ranges from private temporary storage, to group access, to public
access, through to data that supports peer-reviewed Journal papers in perpetuity. The publication
model is further extended by the possibility of Virtual Data -- where only the method of
computation is stored, not necessarily the data itself. Furthermore, virtual data products may
depend on other virtual data products, creating an implicit network of on-demand computation.
This computation may take huge resources, or it may be all within a laptop
Spectroscopic Analysis in the Virtual Observatory Environment with SPLAT-VO
SPLAT-VO is a powerful graphical tool for displaying, comparing, modifying
and analyzing astronomical spectra, as well as searching and retrieving spectra
from services around the world using Virtual Observatory (VO) protocols and
services. The development of SPLAT-VO started in 1999, as part of the Starlink
StarJava initiative, sometime before that of the VO, so initial support for the
VO was necessarily added once VO standards and services became available.
Further developments were supported by the Joint Astronomy Centre, Hawaii until
2009. Since end of 2011 development of SPLAT-VO has been continued by the
German Astrophysical Virtual Observatory, and the Astronomical Institute of the
Academy of Sciences of the Czech Republic. From this time several new features
have been added, including support for the latest VO protocols, along with new
visualization and spectra storing capabilities. This paper presents the history
of SPLAT-VO, it's capabilities, recent additions and future plans, as well as a
discussion on the motivations and lessons learned up to now.Comment: 15 pages, 6 figures, accepted for publication in Astronomy &
Computin
Photoemission study of TiO2/VO2 interfaces
We have measured photoemission spectra of two kinds of TiO-capped VO
thin films, namely, that with rutile-type TiO (r-TiO/VO) and that
with amorphous TiO (a-TiO/VO) capping layers. Below the
Metal-insulator transition temperature of the VO thin films, K,
metallic states were not observed for the interfaces with TiO, in contrast
with the interfaces between the band insulator SrTiO and the Mott insulator
LaTiO in spite of the fact that both TiO and SrTiO are band
insulators with electronic configurations and both VO and LaTiO
are Mott insulators with electronic configurations. We discuss possible
origins of this difference and suggest the importance of the polarity
discontinuity of the interfaces. Stronger incoherent part was observed in
r-TiO/VO than in a-TiO/VO, suggesting Ti-V atomic diffusion due
to the higher deposition temperature for r-TiO/VO.Comment: 5 pages, 6 figure
Observations and Publications in the VO: Is the VO Only for Big Science?
The Virtual Observatory (VO) got started by Big Science projects. We can ask: is the VO an exclusive tool to handle big catalogs from large surveys? We think the VO should contain information from journals, other publications, and non-survey, ``Little Science" observations too. Journals, observatory publications and repositories could be the vehicle to carry non-survey observations to the VO
Engineered valley-orbit splittings in quantum confined nanostructures in silicon
An important challenge in silicon quantum electronics in the few electron
regime is the potentially small energy gap between the ground and excited
orbital states in 3D quantum confined nanostructures due to the multiple valley
degeneracies of the conduction band present in silicon. Understanding the
"valley-orbit" (VO) gap is essential for silicon qubits, as a large VO gap
prevents leakage of the qubit states into a higher dimensional Hilbert space.
The VO gap varies considerably depending on quantum confinement, and can be
engineered by external electric fields. In this work we investigate VO
splitting experimentally and theoretically in a range of confinement regimes.
We report measurements of the VO splitting in silicon quantum dot and donor
devices through excited state transport spectroscopy. These results are
underpinned by large-scale atomistic tight-binding calculations involving over
1 million atoms to compute VO splittings as functions of electric fields, donor
depths, and surface disorder. The results provide a comprehensive picture of
the range of VO splittings that can be achieved through quantum engineering.Comment: 4 pages, 4 figure
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