520 research outputs found
Modelling and performance of Nb SIS mixers in the 1.3 mm and 0.8 mm bands
We describe the modeling and subsequent improvements of SIS waveguide mixers for the 200-270 and 330-370 GHz bands (Blundell, Carter, and Gundlach 1988, Carter et al 1991). These mixers are constructed for use in receivers on IRAM radiotelescopes on Pico Veleta (Spain, Sierra Nevada) and Plateau de Bure (French Alps), and must meet specific requirements. The standard reduced height waveguide structure with suspended stripline is first analyzed and a model is validated through comparison with scale model and working scale measurements. In the first step, the intrinsic limitations of the standard mixer structure are identified, and the parameters are optimized bearing in mind the radioastronomical applications. In the second step, inductive tuning of the junctions is introduced and optimized for minimum noise and maximum bandwidth. In the 1.3 mm band, a DSB receiver temperature of less than 110 K (minimum 80 K) is measured from 180 through 260 GHz. In the 0.8 mm band, a DSB receiver temperature of less than 250 K (minimum 175 K) is obtained between 325 and 355 GHz. All these results are obtained with room-temperature optics and a 4 GHz IF chain having a 500 MHz bandwidth and a noise temperature of 14 K
Field Induced Reduction of the Low Temperature Superfluid Density in YBa2Cu3O6.95
A novel high magnetic field (8 T) spectrometer for muon spin rotation has
been used to measure the temperature dependence of the in-plane magnetic
penetration depth in YBa2Cu3O6.95. At low H and low T, the penetration depth
exhibits the characteristic linear T dependence associated with the energy gap
of a d_x^2-y^2-wave superconductor. However, at higher fields the penetration
depth is essentially temperature independent at low T. We discuss possible
interpretations of this surprising new feature in the low-energy excitation
spectrum.Comment: 8 pages, 4 figures, 1 RevTex file and 4 postscript figure
Un nouveau sérotype de Salmonella : S. alfort = 3,10 : f, g : e, n, x
Pantaléon Jean, Gledel J., Billon Jean, Corbion B., Le Minor L., Le Coueffic E. Un nouveau sérotype de Salmonella : S. alfort = 3,10 : f, g : e,n, x. In: Bulletin de l'Académie Vétérinaire de France tome 127 n°8-9, 1974. pp. 373-374
Assessment of Patient Satisfaction Using a New Augmented Reality Simulation Software for Breast Augmentation: A Prospective Study
Background: Breast augmentation is one of the most frequently performed plastic surgery
procedures. Providing patients with realistic 3D simulations of breast augmentation outcomes
is becoming increasingly common. Until recently, such programs were expensive and required
significant equipment, training, and office space. New simple user-friendly programs have been
developed, but to date there remains a paucity of objective evidence comparing these 3D simulations
with post-operative outcomes. The aim of this study is to assess the aesthetic similarity between a preoperative
3D simulation generated using Arbrea breast simulation software and real post-operative
outcomes, with a focus on patient satisfaction. Methods: The authors conducted a prospective study
of patients requiring breast augmentation. Patients were asked to assess how realistic the simulation
was compared to the one-year post-operative result using the authors’ grading scale for breast
augmentation simulation assessment. Patient satisfaction with the simulations was assessed using
a satisfaction visual analogue scale (VAS) ranging from 0 (not at all satisfied) to 10 (very satisfied).
Patient satisfaction with the surgical outcome was assessed using the BREAST-Q Augmentation
Module. Results: All patients were satisfied with the simulations and with the attained breast
volume, with a mean VAS score of 8.2   1.2. The mean simulation time took 90 s on average. The
differences between the pre-operative and one-year post-operative values of the three BREAST-Q
assessments were found to be statistically significant (p < 0.001). Conclusions: Three-dimensional
simulation is becoming increasingly common in pre-operative planning for breast augmentation. The
present study aimed to assess the degree of similarity of three-dimensional simulations generated
using Arbrea Breast Software and found that the use of the software provided a very satisfying
representation for patients undergoing breast augmentation. However, we recommend informing
patients that only the volume simulation is extremely accurate. On the other hand, it is necessary to
not guarantee an absolute correspondence regarding the breast shape between the simulation and
the post-operative result
Frustrated kinetic energy, the optical sum rule, and the mechanism of superconductivity
The theory that the change of the electronic kinetic energy in a direction
perpendicular to the CuO-planes in high-temperature superconductors is a
substantial fraction of the condensation energy is examined. It is argued that
the consequences of this theory based on a rigorous -axis conductivity sum
rule are consistent with recent optical and penetration depth measurements.Comment: 4 pages (RevTeX) and 2 eps figure
Melting and Dimensionality of the Vortex Lattice in Underdoped YBa2Cu3O6.60
Muon spin rotation measurements of the magnetic field distribution in the
vortex state of the oxygen deficient high-Tc superconductor YBa{2}Cu{3}O{6.60}
reveal a vortex-lattice melting transition at much lower temperature than that
in the fully oxygenated material. The transition is best described by a model
in which adjacent layers of ``pancake'' vortices decouple in the liquid phase.
Evidence is also found for a pinning-induced crossover from a solid 3D to
quasi-2D vortex lattice, similar to that observed in the highly anisotropic
superconductor Bi{2+x}Sr{2-x}CaCu{2}O{8+y}.Comment: 8 pages, 4 figures, 5 postscript file
Hybrid HVDC circuit breaker with self-powered gate drives
The ever increasing electric power demand and the advent of renewable energy sources have revived the interest in high-voltage direct current (HVDC) multi-terminal networks. However, the absence of a suitable circuit breaker or fault tolerant VSC station topologies with the required characteristics (such as operating speed) have, until recently, been an obstacle in the development of large scale multi-terminal networks for HVDC. This paper presents a hybrid HVDC circuit breaker concept which is capable of meeting the requirements of HVDC networks. Simulation results are presented which are validated by experimental results taken from a 2.5kV, 700A rated laboratory prototype
I Me Mine: on a Confusion Concerning the Subjective Character of Experience
In recent debates on phenomenal consciousness, a distinction is sometimes made, after Levine (2001) and Kriegel (2009), between the “qualitative character” of an experience, i.e. the specific way it feels to the subject (e.g. blueish or sweetish or pleasant), and its “subjective character”, i.e. the fact that there is anything at all that it feels like to her. I argue that much discussion of subjective character is affected by a conflation between three different notions. I start by disentangling the three notions in question, under the labels of “for-me-ness”, “me-ness” and “mineness”. Next, I argue that these notions are not equivalent; in particular, there is no conceptual implication from for-me-ness to me-ness or mineness. Empirical considerations based on clinical cases additionally suggest that the three notions may also correspond to different properties (although the claim of conceptual non-equivalence does not depend on this further point). The aim is clarificatory, cautionary but also critical: I examine four existing arguments from subjective character that are fuelled by an undifferentiated use of the three notions, and find them to be flawed for this reason
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