Search results for "switching."

Enhanced Q-switched distributed feedback fiber laser based on acoustic pulses

2009

An acoustically Q-switched distributed feedback fiber laser with enhanced performance is presented. It is based on an FBG written in an erbium doped fiber, in which a dynamic defect is introduced by means of a short acoustic pulse. The performance of the laser depends on the reflectivity of the grating. In this work, we present two different Q-switched distributed feedback fiber lasers realized with active gratings of different reflectivities. Both lasers are characterized at different pump powers and repetition rates. It is shown that the performance of the laser based on the weaker grating was significantly improved with respect to the laser based on the stronger grating. In terms of peak…

Impact of wage penalty on mobility return of French PhDs

2015

International audience; Expatriation of higher-education graduates raises much concern in many countries often in conjunction with talk about the brain drain. It supposedly entails a risk of losing the skills required for a competitive economy. The issue is all the more acute for PhD graduates, who are expected to play a major part in the knowledge economy. However, questions arise as to the causes of such mobility and its consequences for young graduates' individual career paths.

Column-switching techniques for screening of diuretics and probenecid in urine samples

1994

A method based on high-performance liquid chromatography using column-switching is described for the screening of diuretics and probenecid in urine samples. The system uses a 20- x 2.1-mm i.d. precolumn, packed with a Hypersil ODS-C18, 30-microns stationary phase, for the on-line sample cleanup and enrichment. Untreated urine samples are directly injected, and the precolumn is flushed for 1 min with water to eliminate polar matrix components. The retained analytes are then back-flushed by means of a six-port switching valve onto a Hypersil ODS-C18 analytical column (5 microns, 250- x 4-mm i.d.), where they are separated using an acetonitrile/phosphate buffer (pH = 3) gradient elution. Under…

Deadline-based QoS Algorithms for High-performance Networks

2007

Quality of service (QoS) is becoming an attractive feature for high-performance networks and parallel machines because it could allow a more efficient use of resources. Deadline-based algorithms can provide powerful QoS provision. However, the cost associated with keeping ordered lists of packets makes them impractical for high-performance networks. In this paper, we explore how to adapt efficiently the earliest deadline first family of algorithms to the high-speed networks environments. The results show excellent performance using just two virtual channels, FIFO queues, and a cost feasible with today's technology.

Photo-thermal control of surface plasmon mode propagation at telecom wavelengths

2016

Surface plasmon polaritons (SPPs) is the promising versatile platform proposed for guiding electromagnetic waves at nanoscale dimensions. In this context dynamic control of SPPs prop- agation is of paramount importance. Thermo-optical (TO) effect is considered as an efficient technique for performing active control of plasmonic devices. Among the thermo-optical based plasmonic devices demonstrated so far TO coefficient is dominantly provided by a dielectric material on top of the metal sustaining the SPP mode, however, the role of TO properties of the metal has been rarely investigated for plasmonic applications especially at the telecom frequency ranges. Therefore, the aim of this thesis i…

Electrochemically Prepared High-k Thin Films for Resistive Switching Devices

Design of a LLC Resonant Converter for Powering a PEM Electrolyzer

2021

International audience; This paper proposes the design of a LLC resonant converter to supply a proton exchange membrane (PEM) electrolyzer. The PEM requires a low voltage with high current, a reduced output voltage ripple, and an overdamped dynamic behavior of the converter to avoid voltage overshoots. The designed converter allows satisfying the design constraints, minimizing switching and reverse recovery losses; the efficiency is influenced mainly by the output rectifier's conduction losses.

Fronto-parietal homotopy in resting-state functional connectivity predicts task-switching performance

2021

Homotopic functional connectivity reflects the degree of synchrony in spontaneous activity between homologous voxels in the two hemispheres. Previous studies have associated increased brain homotopy and decreased white matter integrity with performance decrements on different cognitive tasks across the life-span. Here, we correlated functional homotopy, both at the whole-brain level and specifically in fronto-parietal network nodes, with task-switching performance in young adults. Cue-to-target intervals (CTI: 300 vs. 1200 ms) were manipulated on a trial-by-trial basis to modulate cognitive demands and strategic control. We found that mixing costs, a measure of task-set maintenance and moni…

The Antecedents of Customer Loyalty - Results of an Empirical Study in the Automotive Industry

2015

Customer satisfaction is regarded as the key to customer loyalty in the automotive industry. However, this relationship is influenced by several other variables, like switching barriers or variety seeking. This paper provides a structural equation model with latent variables for modeling this complex relationship. According to literature, high satisfaction should lead to loyalty but is heavily affected by moderating variables. An empricial study is reported which supports these predictions as well as the arguments on which they are based.

New approach for harmonic mitigation in single-phase five-level CHBMI with fundamental frequency switching

2017

The main objective of this paper is to study and analyse the voltage output waveform of a multilevel inverter, to suggest a new approach for harmonic mitigation improving the converter performance. These last type of converters represent a new technology in the field of DC/AC electrical energy conversion, presenting advantages respect to the traditional converters. In fact, the multilevel power converters present a low harmonic content and a high voltage level. The paper considers a five-level single-phase cascaded H-bridge inverter and fundamental frequency modulation techniques. The voltage waveform analysis has allowed to identify a working area of the converter where there are lowest va…