10,048 research outputs found
Plentiful magnetic moments in oxygen deficient SrTiO3
Correlated band theory is employed to investigate the magnetic and electronic
properties of different arrangements of oxygen di- and tri-vacancy clusters in
SrTiO. Hole and electron doping of oxygen deficient SrTiO yields
various degrees of magnetization as a result of the interaction between
localized magnetic moments at the defected sites. Different kinds of Ti atomic
orbital hybridization are described as a function of the doping level and
defect geometry. We find that magnetism in SrTiO is sensitive to
the arrangement of neighbouring vacancy sites, charge carrier density, and
vacancy-vacancy interaction. Permanent magnetic moments in the absence of
vacancy doping electrons are observed. Our description of the charged clusters
of oxygen vacancies widens the previous descriptions of mono and
multi-vacancies and points out the importance of the controled formation at the
atomic level of defects for the realization of transition metal oxide based
devices with a desirable magnetic performance.Comment: 6 pages, 5 figures, continuation of arXiv:1408.310
Getting Narrower at the Base: The American Curriculum After NCLB
Examines curriculum changes in elementary, middle, and high schools since No Child Left Behind (NCLB) was enacted, requiring regular testing in reading and math. Analyzes shifts in time allocations to four subjects, contributing factors, and implications
Mechatronics & the cloud
Conventionally, the engineering design process has assumed that the design team is able to exercise control over all elements of the design, either directly or indirectly in the case of sub-systems through their specifications. The introduction of Cyber-Physical Systems (CPS) and the Internet of Things (IoT) means that a design team’s ability to have control over all elements of a system is no longer the case, particularly as the actual system configuration may well be being dynamically reconfigured in real-time according to user (and vendor) context and need. Additionally, the integration of the Internet of Things with elements of Big Data means that information becomes a commodity to be autonomously traded by and between systems, again according to context and need, all of which has implications for the privacy of system users. The paper therefore considers the relationship between mechatronics and cloud-basedtechnologies in relation to issues such as the distribution of functionality and user privacy
Privacy matters:issues within mechatronics
As mechatronic devices and components become increasingly integrated with and within wider systems concepts such as Cyber-Physical Systems and the Internet of Things, designer engineers are faced with new sets of challenges in areas such as privacy. The paper looks at the current, and potential future, of privacy legislation, regulations and standards and considers how these are likely to impact on the way in which mechatronics is perceived and viewed. The emphasis is not therefore on technical issues, though these are brought into consideration where relevant, but on the soft, or human centred, issues associated with achieving user privacy
Ab initio study of semiconducting carbon nanotubes adsorbed on the Si(100) surface: diameter- and registration-dependent atomic configurations and electronic properties
We present a first-principles study of semiconducting carbon nanotubes
adsorbed on the unpassivated Si(100) surface. We have found metallicity for the
combined system caused by n-doping of the silicon slab representing the surface
by the SWNT. We confirm this metallicity for nanotubes of different diameters
and chiral angles, and find the effect to be independent of the orientation of
the nanotubes on the surface. We also present adsorption energetics and
configurations which show semiconducting SWNTs farther apart from the surface
and transferring less charge, in comparison with metallic SWNTs of similar
diameter.Comment: Replaces old (Jan 2006) version; more supporting material. 11 pages,
8 figures, 7 table
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