727 research outputs found
Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers
Recent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications
A PRELIMINARY STUDY TO MODEL CARRYING ANGLE VARIATIONS DURING FLEXION-EXTENSION OF THE ELBOW
The aim of this work was to identify an accurate method to evaluate the variability of the carrying angle during the flexion extension of the elbow and to define a mathematical description of this movement applicable in sport and rehabilitation field.
In order to develop this objective, we marked the arm and the forearm by six reflective markers of six healthy subjects performing the flexion extension movement and acquired the coordinates using six infrared cameras (VICON Motion System). Five repeated measures were performed for each subject in order to verify the reliability of the measures. Our results demonstrated that this movement can be easily modelled as a linear variation of the carrying angle in function of the flexion angle. The reliability between repeated measures was high and adopting a linear fit the accuracy was more than 94% in all cases. This is the first study to compute the flexion-extension movement by a carrying angle evaluation
Magnetic breakdown in a normal-metal - superconductor proximity sandwich
We study the magnetic response of a clean normal-metal slab of finite
thickness in proximity with a bulk superconductor. We determine its free energy
and identify two (meta-)stable states, a diamagnetic one where the applied
field is effectively screened, and a second state, where the field penetrates
the normal-metal layer. We present a complete characterization of the first
order transition between the two states which occurs at the breakdown field,
including its spinodals, the jump in the magnetization, and the latent heat.
The bistable regime terminates at a critical temperature above which the sharp
transition is replaced by a continuous cross-over. We compare the theory with
experiments on normal-superconducting cylinders.Comment: 7 pages Revtex, 3 Postscript figures, needs psfig.te
INFLUENCE OF AGE AND HAND GRIP STRENGTH ON FREESTYLE PERFORMANCES IN MASTER SWIMMERS
The aim of our work was to examine whether age and hand grip strength are correlated with 50m, 100m, 200m, 400m, 800m swimming performance times in Master swimmers and how correlation varies considering short, middle or long distances. The main finding of this work was that hand grip strength and age correlated significantly at each distance. Hand grip strength showed a relevant influence on performance time and explained 52% of variance of performance time in 50m race freestyle and only 15% in 800m race. Increasing age was a disadvantageous factor for performance time, and explained 45% of variance of performance time in 800m race freestyle and only 20% in 50 m race
Rough Surface Effect on Meissner Diamagnetism in Normal-layer of N-S Proximity-Contact System
Rough surface effect on the Meissner diamagnetic current in the normal layer
of proximity contact N-S bi-layer is investigated in the clean limit. The
diamagnetic current and the screening length are calculated by use of
quasi-classical Green's function. We show that the surface roughness has a
sizable effect, even when a normal layer width is large compared with the
coherence length . The effect is as large as that
of the impurity scattering and also as that of the finite reflection at the N-S
interface.Comment: 12 pages, 3 figures. To be published in J. Phys. Soc. Jpn. Vol.71-
First demonstration of broadcasting high capacity data in large-core POF-based in-home networks
We report a novel low-cost in-home broadcasting system using a 1-mm core graded-index plastic optical fibre split network reaching up to 35 meters. We demonstrated broadcasting 2.5Gbit/s data to four end-users employing discrete multi-tone modulatio
The excitation spectrum of mesoscopic proximity structures
We investigate one aspect of the proximity effect, viz., the local density of
states of a superconductor-normal metal sandwich. In contrast to earlier work,
we allow for the presence of an arbitrary concentration of impurities in the
structure. The superconductor induces a gap in the normal metal spectrum that
is proportional to the inverse of the elastic mean free path l_N for rather
clean systems. For a mean free path much shorter than the thickness of the
normal metal, we find a gap size proportional to l_N that approaches the
behavior predicted by the Usadel equation (diffusive limit). We also discuss
the influence of interface and surface roughness, the consequences of a
non-ideal transmittivity of the interface, and the dependence of our results on
the choice of the model of impurity scattering.Comment: 7 pages, 8 figures (included), submitted to PR
Quasiclassical theory of superconductivity: a multiple interface geometry
The purpose of the paper is to suggest a new method which allows one to study
multiple coherent reflection/transmissions by partially transparent interfaces
(e.g. in multi-layer mesoscopic structures or grain boundaries in high-Tc's) in
the framework of the quasiclassical theory of superconductivity. It is argued
that typically the trajectory of the particle is a simply connected tree (no
loops) with knots, i.e. the points where interface scattering events occur and
ballistic pieces of the trajectory are mixed. A linear boundary condition for
the 2-component trajectory "wave function" which factorizes matrix (retarded)
Green's function, is formulated for an arbitrary interface, specular or
diffusive. To show the usage of the method, the current response to the vector
potential (the total superfluid density rho_s) of a SS' sandwich with the
different signs of the order parameter in S and S', is calculated. In this
model, a few percent of reflection by the SS' interface transforms the
paramagnetic response (rho_s < 0) created by the zero-energy Andreev bound
states near an ideal interface (see Fauchere et al. PRL, 82, 3336 (1999),
cond-mat/9901112), into the usual diamagnetic one (rho_s >0).Comment: Extended abstract submitted to "Electron Transport in Mesoscopic
Systems", Satellite conference to LT22, Goteborg, 12-15 August, 1999. 2 pages
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