36,162 research outputs found
Quantum Resonances of Weakly Linked, Mesoscopic, Superconducting Dots
We examine quantum properties of mesoscopic, Josephson coupled
superconducting dots, in the limit that charging effects and quantization of
energy levels within the dots are negligible, but quasi-particle transmission
into the weak link is not. We demonstrate that quasi-particle resonances lead
to current-phase relations, which deviate markedly from those of weak links
connecting macroscopic superconductors. Results for the steady state dc
Josephson current of two coupled dots are presented.Comment: Tex, 3 figures available on request to [email protected] (Andy
Martin
Chiral currents in gold nanotubes
Results are presented for the electron current in gold chiral nanotubes
(AuNTs). Starting from the band structure of (4,3) and (5,3) AuNTs, we find
that the magnitude of the chiral currents are greater than those found in
carbon nanotubes. We also calculate the associated magnetic flux inside the
tubes and find this to be higher than the case of carbon nanotubes. Although
(4,3) and (5,3) AuNTs carry transverse momenta of similar magnitudes, the
low-bias magnetic flux carried by the former is far greater than that carried
by the latter. This arises because the low-bias longitudinal current carried by
a (4,3) AuNT is significantly smaller than that of a (5,3) AuNT.Comment: 5 pages, 6 figure
Physical optics for oven-plate scattering prediction
An oven assembly design is described, which will be used to determine the effects of temperature on the electrical properties of materials which are used as coatings for metal plates. Experimentally, these plates will be heated to a very high temperature in the oven assembly, and measured using a microwave reflectance measurement system developed for the NASA Lewis Research Center, Near-Field Facility. One unknown in this measurement is the effect that the oven assembly will have on the reflectance properties of the plate. Since the oven will be much larger than the plate, the effect could potentially be significant as the size of the plate becomes smaller. Therefore, it is necessary to predict the effect of the oven on the measurement of the plate. A method for predicting the oven effect is described, and the theoretical oven effect is compared to experimental results of the oven material. The computer code which is used to predict the oven effect is also described
Numerical radiative transfer with state-of-the-art iterative methods made easy
This article presents an on-line tool (rttools.irap.omp.eu) and its
accompanying software ressources for the numerical solution of basic radiation
transfer out of local thermodynamic equilibrium (LTE). State-of-the-art
stationary iterative methods such as Accelerated -Iteration and
Gauss-Seidel schemes, using a short characteristics-based formal solver are
used. We also comment on typical numerical experiments associated to the basic
non-LTE radiation problem. These ressources are intended for the largest use
and benefit, in support to more classical radiation transfer lectures usually
given at the Master level.Comment: 8 pages, 5 figures, accepted for Eur. J. Phys. - see also (and use!)
http://rttools.irap.omp.e
Oscillating chiral currents in nanotubes: a route to nanoscale magnetic test tubes
With a view to optimising the design of carbon-nanotube (CNT) windmills and
to maximising the internal magnetic field generated by chiral currents, we
present analytical results for the group velocity components of an electron
flux through chiral carbon nanotubes. Chiral currents are shown to exhibit a
rich behaviour and can even change sign and oscillate as the energy of the
electrons is increased. We find that the transverse velocity and associated
angular momentum of electrons is a maximum for non-metallic CNTs with a chiral
angle of 18. Such CNTs are therefore the optimal choice for CNT windmills
and also generate the largest internal magnetic field for a given longitudinal
current. For a longitudinal current of order amps, this field can be
of order Teslas, which is sufficient to produce interesting spintronic
effects and a significant contribution to the self inductance.Comment: 4 pages, 1 figur
Real-life effectiveness of once-daily calcipotriol and betamethasone dipropionate gel vs. ointment formulations in psoriasis vulgaris: final analysis of the 52-week PRO-long study
Background: Topical therapies are the mainstay of treatment for psoriasis vulgaris. The fixed combination of calcipotriol (Cal) 50 mu g/g plus betamethasone 0.5 mg/g (as dipropionate; BD) is a first-line topical treatment and available as a gel or ointment. The use of these fixed combination products was compared in PRO-long, a long-term noninterventional study, for which interim results (4 and 12 weeks) have previously been reported.
Objective: To describe and compare patients' perspectives on the fixed combination gel and ointment formulations; to include efficacy, adherence behaviour, treatment satisfaction and health-related quality of life (HRQoL) aspects during long-term real-life psoriasis management.
Methods: PRO-long was a multicentre, prospective, observational, 52-week study of patients prescribed fixed combination Cal/BD gel or ointment in clinical practice. For final analysis the following were assessed at weeks 24, 36 and 52: differences in the proportion of patients with 'mild'/'very mild' disease according to patient's global assessment of disease severity, adherence behaviour, treatment satisfaction (nine-item treatment satisfaction questionnaire for medication) and HRQoL (Skindex-29).
Results: Patients (n = 328) were prescribed once-daily Cal/BD gel (n = 152) or ointment (n = 176). At week 52, a higher proportion of patients reported that the severity of their psoriasis was 'mild'/'very mild' vs. baseline (gel: 60.2 vs. 47.1%; ointment: 58.8 vs. 42.4%), with greater treatment satisfaction reported in patients using gel vs. those using ointment. A higher proportion of patients found the gel 'easy' to use compared with the ointment (66.7 vs. 45.2%). Daily application of treatment took <= 5 min for 86.1% of patients using gel and 71.0% of patients using ointment.
Conclusion: This real-life study has demonstrated similar effectiveness between the Cal/BD formulations. However, over a 52-week treatment period, patients reported greater treatment satisfaction with the gel, which was considered easier to use, faster to apply and overall a more convenient product
Suppression of Giant Magnetoresistance by a superconducting contact
We predict that current perpendicular to the plane (CPP) giant
magnetoresistance (GMR) in a phase-coherent magnetic multilayer is suppressed
when one of the contacts is superconducting. This is a consequence of a
superconductivity-induced magneto-resistive (SMR) effect, whereby the
conductance of the ferromagnetically aligned state is drastically reduced by
superconductivity. To demonstrate this effect, we compute the GMR ratio of
clean (Cu/Co)_nCu and (Cu/Co)_nPb multilayers, described by an ab-initio spd
tight binding Hamiltonian. By analyzing a simpler model with two orbitals per
site, we also show that the suppression survives in the presence of elastic
scattering by impurities.Comment: 5 pages, 4 figures. Submitted to PR
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