1,558 research outputs found
Some functional forms of Blaschke-Santal\'o inequality
We establish new functional versions of the Blaschke-Santal\'o inequality on
the volume product of a convex body which generalize to the non-symmetric
setting an inequality of K. Ball and we give a simple proof of the case of
equality. As a corollary, we get some inequalities for -concave functions
and Legendre transforms which extend the recent result of Artstein, Klartag and
Milman, with its equality case.Comment: 19 pages, to appear in Mathematische Zeitschrif
On the volume of sections of a convex body by cones
Let be a convex body in . We prove that in small
codimensions, the sections of a convex body through the centroid are quite
symmetric with respect to volume. As a consequence of our estimates we give a
positive answer to a problem posed by M. Meyer and S. Reisner regarding convex
intersection bodies.Comment: 13 page
The Wellness Companion
Issues such as obesity, high blood pressure, and heart disease have been correlated with a sedentary lifestyle. Additionally, many contemporary office jobs consist of deskwork on a computer for almost the entire workday. This can result in back and neck issues. The goal of this project is to limit the harmful effects of sitting for extended periods of time by making an active lifestyle easy and convenient. The Wellness Companion is a portable treadmill that is easy to transport and use in a variety of environments, such as at the library, in school, or at the office
Towards an integrated approach of building-data management through the convergence of building information modelling and internet of things
This contribution presents a possible use of the Building Information Model (BIM) for the implementation of Building Management Systems (BMS) and proposes tools and methods for each critical step of the process. The resulting designed process enables each building stakeholder to work at an earlier stage on the digital model located on a dedicated server. This paper proposes a novel and integrated approach to building-data management and analyses the main obstacles and limitations that may currently affect the practical implementation
De Centrale Archeologische Inventaris: een databank van archeologische vindplaatsen
Tweede artikel uit het eerste CAI-rapport uit 2004. Dit artikel handelt over de organisatie, de opbouw en de structuur van de CAI-databanken
Electron-Beam Manipulation of Silicon Dopants in Graphene
The direct manipulation of individual atoms in materials using scanning probe
microscopy has been a seminal achievement of nanotechnology. Recent advances in
imaging resolution and sample stability have made scanning transmission
electron microscopy a promising alternative for single-atom manipulation of
covalently bound materials. Pioneering experiments using an atomically focused
electron beam have demonstrated the directed movement of silicon atoms over a
handful of sites within the graphene lattice. Here, we achieve a much greater
degree of control, allowing us to precisely move silicon impurities along an
extended path, circulating a single hexagon, or back and forth between the two
graphene sublattices. Even with manual operation, our manipulation rate is
already comparable to the state-of-the-art in any atomically precise technique.
We further explore the influence of electron energy on the manipulation rate,
supported by improved theoretical modeling taking into account the vibrations
of atoms near the impurities, and implement feedback to detect manipulation
events in real time. In addition to atomic-level engineering of its structure
and properties, graphene also provides an excellent platform for refining the
accuracy of quantitative models and for the development of automated
manipulation.Comment: 5 figures, 4 supporting figure
Spin-current driven Dzyaloshinskii-Moriya interaction in the multiferroic BiFeO3 from first-principles
The electrical control of magnons opens up new ways to transport and process
information for logic devices. In magnetoelectrical multiferroics, the
Dzyaloshinskii-Moriya (DM) interaction directly allow for such a control and,
hence, is of major importance. We determine the origin and the strength of the
(converse) spin current DM interaction in the R3c bulk phase of the
multiferroic BiFeO3 based on density functional theory. Our data supports only
the existence of one DM interaction contribution originating from the spin
current model. By exploring then magnon dispersion in the full Brillouin Zone,
we show that the exchange is isotropic, but the DM interaction and anisotropy
prefer any propagation and any magnetization direction within the full (111)
plane. Our work emphasizes the significance of the asymmetric potential induced
by the spin current over the structural asymmetry induced by the anionic
octahedron in multiferroics such as BiFeO3
Raman-modes of index-identified free-standing single-walled carbon nanotubes
Using electron diffraction on free-standing single-walled carbon nanotubes we
have determined the structural indices (n,m) of tubes in the diameter range
from 1.4 to 3nm. On the same free-standing tubes we have recorded Raman spectra
of the tangential modes and the radial breathing mode. For the smaller
diameters (1.4-1.7nm) these measurements confirm previously established radial
breathing mode frequency versus diameter relations, and would be consistent
with the theoretically predicted proportionality to the inverse diameter.
However, for extending the relation to larger diameters, either a yet
unexplained environmental constant has to be assumed, or the linear relation
has to be abandoned.Comment: 4 pages, 4 figures, +additional materials (select PostScript to
obtain it
Quand la recherche est au service des pratiques de formation à l’enseignement faisant usage du numérique, et vice-versa
Les technologies numériques sont de plus en plus présentes dans de nombreuses dimensions de nos pratiques de formation à l’enseignement. Souvent imposées rapidement et sans fondement, elles ne sont pas nécessairement intégrées de manière appropriée dans les contextes de formation universitaire ou en enseignement supérieur (Albero, 2011). Par exemple, plusieurs formateurs sont amenés à donner des cours en ligne (ou de manière hybride) sans les connaissances ou l’accompagnement nécessaire afin ..
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