2,626 research outputs found
Magnetic field relaxation in ferromagnetic Ising systems
We analyze the thermal magnetization reversal processes in magnetic grains.
Two experiments are carried out: swtiching time and switching field
experiments. In both cases, we find that the simulated behavior is coherent
with existing experimental data (the streched exponent of the switching time
experiment increases with the temperature and is superior to unity; there
exists a master curve for the switching field experiment). Moreover, we
simulated magnetic grains in a region of parameters where no experimental data
are available. We find that the relaxation time distribution is
gaussian, and we find the existence of a strong field regime.Comment: 9 pages, 7 figures, J.M.M.
Wireless Keypads - A New Classroom Technology Using Enhanced Multiple-Choice Questions
This article discusses the advantages of using wireless keypads in the
Lecture/classroom. This new technology requires multiple-choice (MC) questions
to mate with the keypad entry features of these devices. The format of the
traditional MC response is constrained to five choices and only one best
response is allowed. For this reason, we propose enhancements to the
traditional MC question. This enhanced MC question allows as many as ten
answers. The answers can vary in their degree of correctness and can be
assigned partial credit. By combining wireless keypads and multiple-choice
questions, we can readily perform both formative and summative assessments of
student learning. Examples and classroom applications are presented.Comment: pdf file, 8 pages,
Heterogeneous multireference alignment: a single pass approach
Multireference alignment (MRA) is the problem of estimating a signal from
many noisy and cyclically shifted copies of itself. In this paper, we consider
an extension called heterogeneous MRA, where signals must be estimated, and
each observation comes from one of those signals, unknown to us. This is a
simplified model for the heterogeneity problem notably arising in cryo-electron
microscopy. We propose an algorithm which estimates the signals without
estimating either the shifts or the classes of the observations. It requires
only one pass over the data and is based on low-order moments that are
invariant under cyclic shifts. Given sufficiently many measurements, one can
estimate these invariant features averaged over the signals. We then design
a smooth, non-convex optimization problem to compute a set of signals which are
consistent with the estimated averaged features. We find that, in many cases,
the proposed approach estimates the set of signals accurately despite
non-convexity, and conjecture the number of signals that can be resolved as
a function of the signal length is on the order of .Comment: 6 pages, 3 figure
Constitutional Procedure for the Reform of the Supreme Court of Canada
L'auteur nous trace l'évolution de la Cour suprême du Canada créée en 1875 ainsi que des implications pour cette Cour, de la venue de la Loi constitutionnelle de1982, spécialement des articles 41(d) et 42(l)(d). Il exprime son point de vue quant au nombre de juges qui doivent siéger, aux quotas régionaux, aux méthodes de sélection. Il examine aussi la question de savoir si la Cour suprême doit continuer d'être le tribunal général d'appel au Canada ou si elle devrait se spécialiser en droit public et constitutionnel
The Fiercest Debate: Cecil A. Wright, the Benchers and Legal Education in Ontario 1923-1957
In the dozen years after the end of the Second World War, long-standing conflicts about the nature of education for the legal profession in Ontario became especially acute. Fortunately, climax and successful compromise came in 1957. In that year the Law Society of Upper Canada, which had controlled legal education and admission to practice from the early days of the Colony of Upper Canada, gave up its monopoly of legal education and conceded an equal position in this respect to Ontario universities willing and able to enter the field. Several were, and promptly did so. Indeed the University of Toronto was already there. For many decades it had been teaching law, but the Law Society refused proper recognition to the University of Toronto law degrees for purposes of admission to the legal profession in the Province
Preparation, characterization, and electrical properties of epitaxial NbO2 thin film lateral devices
Epitaxial NbO2 (110) films, 20 nm thick, were grown by pulsed laser
deposition on Al2O3 (0001) substrates. The Ar/O2 total pressure during growth
was varied to demonstrate the gradual transformation between NbO2 and Nb2O5
phases, which was verified using x-ray diffraction, x-ray photoelectron
spectroscopy, and optical absorption measurements. Electric resistance
threshold switching characteristics were studied in a lateral geometry using
interdigitated Pt top electrodes in order to preserve the epitaxial crystalline
quality of the films. Volatile and reversible transitions between high and low
resistance states were observed in epitaxial NbO2 films, while irreversible
transitions were found in case of Nb2O5 phase. Electric field pulsed current
measurements confirmed thermally-induced threshold switching.Comment: This is an author-created, un-copyedited version of an article
accepted for publication in Journal of Physics D: Applied Physics. IOP
Publishing Ltd is not responsible for any errors or omissions in this version
of the manuscript or any version derived from it. The Version of Record is
available online at http://dx.doi.org/10.1088/0022-3727/48/33/33530
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