GaInAs monolithic photoreceiver integrating p-i-n/JFET withdiffused junctions and a resistor

An integrated p-i-n/JFET/resistor has been developed using a GaInAs epitaxial structure grown on a planar substrate A four-layered structure allows separate optimization of both active devices. Owing to the good performances and high reliability of individual components, the sensitivity of these monolithic photoreceivers is evaluated as -29 dBm at 560 Mb/s (10^-9 bit error rate). Remarkable stability over time is exhibited     

Semiconductor optical space switches

This paper reviews the various optical space switch structures on III-V semiconductor material. Their characteristics are discussed in the context of optical transport and switching network applications exploiting wavelength division multiplexing     

Daily generation management at Electricite de France: from planningtowards real time

The application of new optimization methods to the daily operation of power plants by Electricite de France is reviewed. A critical analysis of the modeling and the methods used in daily operation are presented. The methodological improvements that have been implemented are considered. An overview of the new perspectives offered by the upgrading of the hardware system that has been implemented at the national control center level is presented. The new system enables access to and display of the requisite data for an online generation scheduling optimization. By looking at the difficulties created by the upgrading mentioned above, it is shown that the recent methodological developments offer major advantages     

Compte rendu La rêve: Sa nature, sa fonction et une méthode d'analyse.

Reviews the book, La rêve: Sa nature, sa fonction et une méthode d'analyse by George W. Baylor and Daniel Deslauriers (1987). This book consists of 85 pages, notes and bibliography included. The work is divided in four chapters. The motif of the title is evident in the first chapter. The three other chapters expose a method of analysis advanced by the authors. On the whole, a method interesting for research but a exercise at the very least harassing in practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

High speed, high capacity ATM optical switches for futuretelecommunication transport networks

This paper describes the work carried out in the RACE Project R2039 ATMOS (asynchronous transfer mode optical switching). The project is briefly illustrated, together with its main goal: to develop and assess concepts and technology suitable for optical fast packet switching. The project's technical approach consisted in the exploitation of the space and wavelength domains for fast routing and buffering: The major achievements are then reported. Four different switch architecture concepts have been proposed, investigated and developed, all based on a high speed optical routing matrix electrically controlled at lower speed. The basic optical key components and subsystems (wavelength converters, space switches and optical buffers) are described in detail, with the outstanding results obtained and the corresponding projected performance. In particular, system demonstration of wavelength conversion at 10 and 20 Gb/s has been realized, to show the usefulness of the ATMOS technology both to implement optimized high performance optical packet-switching fabrics as well as transparent optical circuit-routing nodes. Four rack-mounted, reduced size demonstrators of basic switching matrices have been designed and implemented scalable to real system sizes. The obtained good results in terms of bit error rate and hardware integration are reported, showing that ATM switches are feasible with state of-the-art optical technology     

30 GHz bandwidth, 1.55 μm MQW-DFB laser diode based on a newmodulation scheme

The authors present a new concept of modulation for a 1.55 μm DFB MQW laser diode allowing generation of millimetre waves. The method consists in modulating the saturable absorber of a two-section laser. The improvements brought by the new concept are evaluated theoretically and have been verified experimentally for the first time. In particular, a 30 GHz cutoff frequency has been measured     

Monolithic photoreceiver integrating GaInAs PIN/JFET with diffused junctions

A new integrated PIN/JFET using an original three-layer GalnAs structure has been developed in order to optimise both devices separately. Thanks to the good performances and high reliability of individual components, the sensitivity of such monolithic photoreceivers is ? 33.7 dBm for a 10?9 bit error rate at 140 Mbit/s.     

Dynamic in vivo (31)P nuclear magnetic resonance study of Saccharomyces cerevisiae in glucose-limited chemostat culture during the aerobic-anaerobic shift

The purpose of this work was to analyse in vivo the influence of sudden oxygen depletion on Saccharomyces cerevisiae, grown in glucose-limited chemostat culture, using a recently developed cyclone reactor coupled with (31)P NMR spectroscopy. Before, during and after the transition, intracellular and extracellular phosphorylated metabolites as well as the pHs in the different cellular compartments were monitored with a time resolution of 2.5 min. The employed integrated NMR bioreactor system allowed the defined glucose-limited continuous cultivation of yeast at a density of 75 g DW/l and a p(O(2)) of 30% air saturation. A purely oxidative metabolism was maintained at all times. In vivo (31)P NMR spectra obtained were of excellent quality and even allowed the detection of phosphoenolpyruvate (PEP). During the switch from aerobic to anaerobic conditions, a rapid, significant decrease of intracellular ATP and PEP levels was observed and the cytoplasmic pH decreased from 7.5 to 6.8. This change, which was accompanied by a transient influx of extracellular inorganic phosphate (P(i)), appeared to correlate linearly with the decrease of the ATP concentration, suggesting that the cause of the partial collapse of the plasma membrane pH gradient was a reduced availability of ATP. The complete phosphorous balance established from our measurement data showed that polyphosphate was not the source of the increased intracellular P(i). The derived intracellular P(i), ATP and ADP concentration data confirmed that the glycolytic flux at the level of glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase and enolase enzymes is mainly controlled by thermodynamic constraints.     

Two-material optimization of plate armour for blast mitigation using hybrid cellular automata

With the increased use of improvised explosive devices in regions at war, the threat to military and civilian life has risen. Cabin penetration and gross acceleration are the primary threats in an explosive event. Cabin penetration crushes occupants, damaging the lower body. Acceleration causes death at high magnitudes. This investigation develops a process of designing armour that simultaneously mitigates cabin penetration and acceleration. The hybrid cellular automaton (HCA) method of topology optimization has proven efficient and robust in problems involving large, plastic deformations such as crash impact. Here HCA is extended to the design of armour under blast loading. The ability to distribute two metallic phases, as opposed to one material and void, is also added. The blast wave energy transforms on impact into internal energy (IE) inside the solid medium. Maximum attenuation occurs with maximized IE. The resulting structures show HCA's potential for designing blast mitigating armour structures.