1,217 research outputs found
Proximity effects and characteristic lengths in ferromagnet-superconductor structures
We present an extensive theoretical investigation of the proximity effects
that occur in Ferromagnet/Superconductor () systems. We use a numerical
method to solve self consistently the Bogoliubov-de Gennes equations in the
continuum. We obtain the pair amplitude and the local density of states (DOS),
and use these results to extract the relevant lengths characterizing the
leakage of superconductivity into the magnet and to study spin splitting into
the superconductor. These phenomena are investigated as a function of
parameters such as temperature, magnet polarization, interfacial scattering,
sample size and Fermi wavevector mismatch, all of which turn out to have
important influence on the results. These comprehensive results should help
characterize and analyze future data and are shown to be in agreement with
existing experiments.Comment: 24 pages, including 26 figure
Near-infrared-actuated devices for remotely controlled drug delivery
A reservoir that could be remotely triggered to release a drug would enable the patient or physician to achieve on-demand, reproducible, repeated, and tunable dosing. Such a device would allow precise adjustment of dosage to desired effect, with a consequent minimization of toxicity, and could obviate repeated drug administrations or device implantations, enhancing patient compliance. It should exhibit low off-state leakage to minimize basal effects, and tunable on-state release profiles that could be adjusted from pulsatile to sustained in real time. Despite the clear clinical need for a device that meets these criteria, none has been reported to date to our knowledge. To address this deficiency, we developed an implantable reservoir capped by a nanocomposite membrane whose permeability was modulated by irradiation with a near-infrared laser. Irradiated devices could exhibit sustained on-state drug release for at least 3 h, and could reproducibly deliver short pulses over at least 10 cycles, with an on/off ratio of 30. Devices containing aspart, a fast-acting insulin analog, could achieve glycemic control after s.c. implantation in diabetic rats, with reproducible dosing controlled by the intensity and timing of irradiation over a 2-wk period. These devices can be loaded with a wide range of drug types, and therefore represent a platform technology that might be used to address a wide variety of clinical indications
Three-dimensional conceptual model for service-oriented simulation
In this letter, we propose a novel three-dimensional conceptual model for an
emerging service-oriented simulation paradigm. The model can be used as a
guideline or an analytic means to find the potential and possible future
directions of the current simulation frameworks. In particular, the model
inspects the crossover between the disciplines of modeling and simulation,
service-orientation, and software/systems engineering. Finally, two specific
simulation frameworks are studied as examples.Comment: 7 pages, 1 figures, 3 table, Journal of Zhejiang University SCIENCE
A, 2009, 10(8): 1075-108
High-contrast imaging constraints on gas giant planet formation - The Herbig Ae/Be star opportunity
Planet formation studies are often focused on solar-type stars, implicitly
considering our Sun as reference point. This approach overlooks, however, that
Herbig Ae/Be stars are in some sense much better targets to study planet
formation processes empirically, with their disks generally being larger,
brighter and simply easier to observe across a large wavelength range. In
addition, massive gas giant planets have been found on wide orbits around early
type stars, triggering the question if these objects did indeed form there and,
if so, by what process. In the following I briefly review what we currently
know about the occurrence rate of planets around intermediate mass stars,
before discussing recent results from Herbig Ae/Be stars in the context of
planet formation. The main emphasis is put on spatially resolved polarized
light images of potentially planet forming disks and how these images - in
combination with other data - can be used to empirically constrain (parts of)
the planet formation process. Of particular interest are two objects, HD100546
and HD169142, where, in addition to intriguing morphological structures in the
disks, direct observational evidence for (very) young planets has been
reported. I conclude with an outlook, what further progress we can expect in
the very near future with the next generation of high-contrast imagers at 8-m
class telescopes and their synergies with ALMA.Comment: Accepted by Astrophysics and Space Science as invited short review in
special issue about Herbig Ae/Be stars; 12 pages incl. 5 figures, 2 tables
and reference
Shape coexistence from lifetime and branching-ratio measurements in 68,70Ni
© 2016 The Author(s) Shape coexistence near closed-shell nuclei, whereby states associated with deformed shapes appear at relatively low excitation energy alongside spherical ones, is indicative of the rapid change in structure that can occur with the addition or removal of a few protons or neutrons. Near 68Ni (Z=28, N=40), the identification of shape coexistence hinges on hitherto undetermined transition rates to and from low-energy 0+ states. In 68,70Ni, new lifetimes and branching ratios have been measured. These data enable quantitative descriptions of the 0+ states through the deduced transition rates and serve as sensitive probes for characterizing their nuclear wave functions. The results are compared to, and consistent with, large-scale shell-model calculations which predict shape coexistence. With the firm identification of this phenomenon near 68Ni, shape coexistence is now observed in all currently accessible regions of the nuclear chart with closed proton shells and mid-shell neutrons
Properties of excited states in Ge77
The nucleus Ge77 was studied through the Ge76(C13,C12)Ge77 reaction at a sub-Coulomb energy. The angular distributions of Îł rays depopulating excited states in Ge77 were measured in order to constrain spin and parity assignments. Some of these assignments are of use in connection with neutrinoless double beta decay, where the population of states near the Fermi surface of Ge76 was recently explored using transfer reactions
Optical Sum Rule in Finite Bands
In a single finite electronic band the total optical spectral weight or
optical sum carries information on the interactions involved between the charge
carriers as well as on their band structure. It varies with temperature as well
as with impurity scattering. The single band optical sum also bears some
relationship to the charge carrier kinetic energy and, thus, can potentially
provide useful information, particularly on its change as the charge carriers
go from normal to superconducting state. Here we review the considerable
advances that have recently been made in the context of high oxides, both
theoretical and experimental.Comment: Review article accepted for publication in J. Low Temp. Phys. 29
pages, 33 figure
Measurement of W Polarisation at LEP
The three different helicity states of W bosons produced in the reaction e+
e- -> W+ W- -> l nu q q~ at LEP are studied using leptonic and hadronic W
decays. Data at centre-of-mass energies \sqrt s = 183-209 GeV are used to
measure the polarisation of W bosons, and its dependence on the W boson
production angle. The fraction of longitudinally polarised W bosons is measured
to be 0.218 \pm 0.027 \pm 0.016 where the first uncertainty is statistical and
the second systematic, in agreement with the Standard Model expectation
Measurement of the Atmospheric Muon Spectrum from 20 to 3000 GeV
The absolute muon flux between 20 GeV and 3000 GeV is measured with the L3
magnetic muon spectrometer for zenith angles ranging from 0 degree to 58
degree. Due to the large exposure of about 150 m2 sr d, and the excellent
momentum resolution of the L3 muon chambers, a precision of 2.3 % at 150 GeV in
the vertical direction is achieved.
The ratio of positive to negative muons is studied between 20 GeV and 500
GeV, and the average vertical muon charge ratio is found to be 1.285 +- 0.003
(stat.) +- 0.019 (syst.).Comment: Total 32 pages, 9Figure
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