2,675 research outputs found
Radiation comb generation with extended Josephson junctions
We propose the implementation of a Josephson radiation comb generator (JRCG)
based on an extended Josephson junction subject to a time dependent magnetic
field. The junction critical current shows known diffraction patterns and
determines the position of the critical nodes when it vanishes. When the
magnetic flux passes through one of such critical nodes, the superconducting
phase must undergo a -jump to minimize the Josephson energy.
Correspondingly a voltage pulse is generated at the extremes of the junction.
Under periodic driving this allows us to produce a comb-like voltage pulses
sequence. In the frequency domain it is possible to generate up to hundreds of
harmonics of the fundamental driving frequency, thus mimicking the frequency
comb used in optics and metrology. We discuss several implementations through a
rectangular, cylindrical and annular junction geometries, allowing us to
generate different radiation spectra and to produce an output power up to
~pW at ~GHz for a driving frequency of ~MHz.Comment: 4+ pages, 4 color figure
Photonic heat conduction in Josephson-coupled Bardeen-Cooper-Schrieffer superconductors
We investigate the photon-mediated heat flow between two Josephson-coupled
Bardeen-Cooper-Schrieffer (BCS) superconductors. We demonstrate that in
standard low temperature experiments involving temperature-biased
superconducting quantum interference devices (SQUIDs), this radiative
contribution is negligible if compared to the direct galvanic one, but it
largely exceeds the heat exchanged between electrons and the lattice phonons.
The corresponding thermal conductance is found to be several orders of
magnitude smaller, for real experiments setup parameters, than the universal
quantum of thermal conductance, kappa_0(T)=pi k_B^2T/6hbar.Comment: 8 pages, 6 figure
Identification of rainy periods from ground based microwave radiometry
AbstractIn this paper the authors present the results of a study aiming at detecting rainy data in measurements collected by a dual band ground-based radiometer.The proposed criterion is based on the ratio of the brightness temperatures observed in the 20–30 GHz band without need of any ancillary information. A major result obtained from the probability density of the ratio computed over one month of data is the identification of threshold values between clear sky, cloudy sky and rainy sky, respectively. A linear fit performed by using radiometric data and concurrent rain gauge measurements shows a correlation coefficient equal to 0.56 between the temperature ratio and the observed precipitation
Effect of soy on metabolic syndrome and cardiovascular risk factors : a randomized controlled trial
Background: Cardiovascular diseases are currently the commonest cause of death worldwide. Different strategies for their primary prevention have been planned, taking into account the main known risk factors, which include an atherogenic lipid profile and visceral fat excess. Methods: The study was designed as a randomized, parallel, single-center study with a nutritional intervention duration of 12 weeks. Whole soy foods corresponding to 30 g/day soy protein were given in substitution of animal foods containing the same protein amount. Results: Soy nutritional intervention resulted in a reduction in the number of MetS features in 13/26 subjects. Moreover, in the soy group we observed a significant improvement of median percentage changes for body weight ( 121.5 %) and BMI ( 121.5 %), as well as for atherogenic lipid markers, namely TC ( 124.85 %), LDL-C ( 125.25 %), non-HDL-C ( 127.14 %) and apoB ( 1214.8 %). Since the majority of the studied variables were strongly correlated, three factors were identified which explained the majority (52 %) of the total variance in the whole data set. Among them, factor 1, which loaded lipid and adipose variables, explained the 22 % of total variance, showing a statistically significant difference between treatment arms (p = 0.002). Conclusions: The inclusion of whole soy foods (corresponding to 30 g/day protein) in a lipid-lowering diet significantly improved a relevant set of biomarkers associated with cardiovascular risk
Performance studies of the Belle II Silicon Vertex Detector with data taken at the DESY test beam in April 2016
Belle II is a multipurpose detector currently under construction which will be operated at the next generation B-factory SuberKEKB in Japan. Its main devices for the vertex reconstruction are the Silicon Vertex Detector (SVD) and the Pixel Detector (PXD). In April 2016 a sector of the Belle II SVD and PXD have been tested in a beam of high energetic electrons at the test beam facility at DESY Hamburg (Germany). We report here the results for the hit efficiency estimation and the measurement of the resolution for the Belle II silicon vertex etector. We find that the hit efficiencies are on average above 99.5% and that the measured resolution is within the expectations
The Belle II SVD detector
The Silicon Vertex Detector (SVD) is one of the main detectors in the Belle II experiment at KEK, Japan. In combination with a pixel detector, the SVD determines precise decay vertex and low-momentum track reconstruction. The SVD ladders are being developed at several institutes. For the development of the tracking algorithm as well as the performance estimation of the ladders, beam tests for the ladders were performed. We report an overview of the SVD development, its performance measured in the beam test, and the prospect of its assembly and commissioning until installation
Performance studies of the Belle II Silicon Vertex Detector with data taken at the DESY test beam in April 2016
Belle II is a multipurpose detector currently under construction which will be operated at the next generation B-factory SuberKEKB in Japan. Its main devices for the vertex reconstruction are the Silicon Vertex Detector (SVD) and the Pixel Detector (PXD). In April 2016 a sector of the Belle II SVD and PXD have been tested in a beam of high energetic electrons at the test beam facility at DESY Hamburg (Germany). We report here the results for the hit efficiency estimation and the measurement of the resolution for the Belle II silicon vertex etector. We find that the hit efficiencies are on average above 99.5% and that the measured resolution is within the expectations
- …