604 research outputs found
Magnetic dipole induced guided vortex motion
We present evidence of magnetically controlled guided vortex motion in a
hybrid superconductor/ferromagnet nanosystem consisting of an Al film on top of
a square array of permalloy square rings. When the rings are magnetized with an
in-plane external field H, an array of point-like dipoles with moments
antiparallel to H, is formed. The resulting magnetic template generates a
strongly anisotropic pinning potential landscape for vortices in the
superconducting layer. Transport measurements show that this anisotropy is able
to confine the flux motion along the high symmetry axes of the square lattice
of dipoles. This guided vortex motion can be either re-routed by 90 degrees by
simply changing the dipole orientation or even strongly suppressed by inducing
a flux-closure magnetic state with very low stray fields in the rings.Comment: 5 pages, 3 figure
A simple model for simulation of growth and development in grapevine (Vitis vinifera L.). 2. Model validation
A simple model for the simulation of growth and development of Sangiovese vines has been presented in a previous paper. In this paper the model is validated to examine whether the description of the physiological relationships in the model describe the growth of grapevine (cv. Sangiovese) realistically. Furthermore, the model was adapted and validated for the simulation of growth of another cultivar (cv. Cabernet Sauvignon). Comparisons of simulated and experimental data for both cultivars reveal that the model made good predictions of vine growth for the whole growing season
A simple model for simulation of growth and development in grapevine (Vitis vinifera L.). 1. Model description
A simple simulation model for growth of grapevine (Vitis vinifera L. cv. Sangiovese) is presented which mainly bases on analytical results from field experiments with plants free of visible stress and diseases. In the model leaf area development is defined as a function of temperature, biomass accumulation as a function of intercepted radiation and fruit growth is calculated from a linear increase of the fruit biomass index with time. The assumptions are discussed and comparisons between simulated and measured results are shown
Operational Numerical Weather Prediction systems based on Linux cluster architectures
The progress in weather forecast and atmospheric science has been always closely linked to the improvement of computing technology. In order to have more accurate weather forecasts and climate predictions, more powerful computing resources are needed, in addition to more complex and better-performing numerical models. To overcome such a large computing request, powerful workstations or massive parallel systems have been used. In the last few years, parallel architectures, based on the Linux operating system, have been introduced and became popular,
representing real“high performance–low cost” systems. In this work the Linux cluster experience achieved at the Laboratory for Meteorology and Environmental Analysis (LaMMA-CNR-IBIMET) is described and tips and performances analysed
Entangling macroscopic oscillators exploiting radiation pressure
It is shown that radiation pressure can be profitably used to entangle {\it
macroscopic} oscillators like movable mirrors, using present technology. We
prove a new sufficient criterion for entanglement and show that the achievable
entanglement is robust against thermal noise. Its signature can be revealed
using common optomechanical readout apparatus.Comment: 4 pages, 2 eps figures, new separability criterion added, new figure
2, authors list change
Classification of Light-Induced Desorption of Alkali Atoms in Glass Cells Used in Atomic Physics Experiments
We attempt to provide physical interpretations of light-induced desorption
phenomena that have recently been observed for alkali atoms on glass surfaces
of alkali vapor cells used in atomic physics experiments. We find that the
observed desorption phenomena are closely related to recent studies in surface
science, and can probably be understood in the context of these results. If
classified in terms of the photon-energy dependence, the coverage and the
bonding state of the alkali adsorbates, the phenomena fall into two categories:
It appears very likely that the neutralization of isolated ionic adsorbates by
photo-excited electron transfer from the substrate is the origin of the
desorption induced by ultraviolet light in ultrahigh vacuum cells. The
desorption observed in low temperature cells, on the other hand, which is
resonantly dependent on photon energy in the visible light range, is quite
similar to light-induced desorption stimulated by localized electronic
excitation on metallic aggregates. More detailed studies of light-induced
desorption events from surfaces well characterized with respect to alkali
coverage-dependent ionicity and aggregate morphology appear highly desirable
for the development of more efficient alkali atom sources suitable to improve a
variety of atomic physics experiments.Comment: 6 pages, 1 figure; minor corrections made, published in e-Journal of
Surface Science and Nanotechnology at
http://www.jstage.jst.go.jp/article/ejssnt/4/0/4_63/_articl
Continuous variable entanglement by radiation pressure
We show that the radiation pressure of an intense optical field impinging on
a perfectly reflecting vibrating mirror is able to entangle in a robust way the
first two optical sideband modes. Under appropriate conditions, the generated
entangled state is of EPR type [A. Einstein, {\it et al.}, Phys. Rev. {\bf 47},
777 (1935)].Comment: 11 pages, 3 figure
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