222 research outputs found
Measurements of critical current diffraction patterns in annular Josephson junctions
We report systematic measurements of the critical current versus magnetic
field patterns of annular Josephson junctions in a wide magnetic field range. A
modulation of the envelope of the pattern, which depends on the junction width,
is observed. The data are compared with theory and good agreement is found.Comment: 4 pages, 5 figure
Whispering Vortices
Experiments indicating the excitation of whispering gallery type
electromagnetic modes by a vortex moving in an annular Josephson junction are
reported. At relativistic velocities the Josephson vortex interacts with the
modes of the superconducting stripline resonator giving rise to novel
resonances on the current-voltage characteristic of the junction. The
experimental data are in good agreement with analysis and numerical
calculations based on the two-dimensional sine--Gordon model.Comment: 5 pages, 5 figures, text shortened to fit 4 pages, correction of
typo
Experimental realization of a relativistic fluxon ratchet
We report the observation of the ratchet effect for a relativistic flux
quantum trapped in an annular Josephson junction embedded in an inhomogeneous
magnetic field. In such a solid state system mechanical quantities are
proportional to electrical quantities, so that the ratchet effect represents
the realization of a relativistic-flux-quantum-based diode. Mean static voltage
response, equivalent to directed fluxon motion, is experimentally demonstrated
in such a diode for deterministic current forcing both in the overdamped and in
the underdamped dynamical regime. In the underdamped regime, the recently
predicted phenomenon of current reversal is also recovered in our fluxon
ratchet.Comment: 4 pages, 6 figures. To appear in PHYSICA
Chlamydophila pecorum in fetuses of mediterranean buffalo (bubalus bubalis) bred in Italy
In order to study the role played by the different species of Chlamydophila in causing abortions in Mediterranean buffalo, the Authors examined 164 fetuses from 80 different buffalo herds in Southern Italy. Three fetuses, came from two different herds, were positive. Our study confirms the pathogenic role of C. pecorum in buffalo, not only as a cause of neuropathology in calves but as an infectious abortive agent
Vacuum gauge from ultrathin MoS2 transistor
We fabricate monolayer MoS2 field effect transistors and study their electric
characteristics from 10^-6 Torr to atmospheric air pressure. We show that the
threshold voltage of the transistor increases with the growing pressure. Hence,
we propose the device as an air pressure sensor, showing that it is
particularly suitable as a low power consumption vacuum gauge. The device
functions on pressure-dependent O2, N2 and H2O molecule adsorption that affect
the n-doping of the MoS2 channel.Comment: 10 pages, 4 figure - conference pape
Experimental investigation of flux motion in exponentially shaped Josephson junctions
We report experimental and numerical analysis of expontentially shaped long
Josephson junctions with lateral current injection. Quasi-linear flux flow
branches are observed in the current-voltage characteristic of the junctions in
the absence of magnetic field. A strongly asymmetric response to an applied
magnetic field is also exhibited by the junctions. Experimental data are found
in agreement with numerical predictions and demonstrate the existence of a
geometry-induced potential experienced by the flux quanta in nonuniform width
junctions.Comment: 16 pg, 8 figures, Submitted in PRB March
A Case Study of Malignant Edema in Postpartum Mediterranean Buffaloes (Bubalus bubalis)
The paper describes for the first time four cases of postparturient malignant edema in water buffaloes due to Clostridium septicum (Cl. septicum). The study was carried out on four primiparous buffaloes that showed swelling of perineal and perivulvar areas, fever and agalactia a few hours after calving. Two of them died within 20 hours after calving. The other two developed edema in the skeletal muscles of one leg and were treated with sulfadiazine-trimethoprim for 10 days. The clinical signs completely resolved. Culture and molecular investigations identified the pathogen isolated from exudate taken from the vulva as Cl. septicum. The isolate showed multi-drug resistance. In the management of infection due to Cl. septicum, timely diagnosis and the chirurgic curettage, associated with a broad-spectrum antibiotic therapy, were found to be sufficient for the survival and recovery of the infected animals
Testing the Kibble-Zurek Scenario with Annular Josephson Tunnel Junctions
In parallel with Kibble's description of the onset of phase transitions in
the early universe, Zurek has provided a simple picture for the onset of phase
transitions in condensed matter systems, strongly supported by agreement with
experiments in He3. In this letter we show how experiments with annular
Josephson tunnel Junctions can and do provide further support for this
scenario.Comment: Revised version with correct formula for the Swihart velocity. The
results are qualitatively the same as with the previous version but differ
quantitatively. 4 pages, RevTe
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