An FPGA-based real-time event sampler

This paper presents the design and FPGA-implementation of a sampler that is suited for sampling real-time events in embedded systems. Such sampling is useful, for example, to test whether real-time events are handled in time on such systems. By designing and implementing the sampler as a logic analyzer on an FPGA, several design parameters can be explored and easily modified to match the behavior of different kinds of embedded systems. Moreover, the trade-off between price and performance becomes easy, as it mainly exists of choosing the appropriate type and speed grade of an FPGA family

Contributions of chemistry in early day Los Alamos

During 1943--1945, the premier physics laboratory in the world was at Los Alamos, but chemistry contributions were vital. Major chemical impacts on the success of the Los Alamos wartime mission included electrochemistry, which found the true melting point of plutonium metal to be hundreds of degrees lower than anticipated. This discovery had profound simplifying effects regarding crucibles to contain molten plutonium and on its production. Other significant chemical contributions involved constant purification of plutonium for reuse, producing carrier-free gamma sources at unprecedented kilo-curie levels, and high polonium work. 8 refs

Chemical approach to the deposition of textured CeO₂ buffer layers based on sol gel dip coating

The widespread use of vacuum techniques for the development of coated conductors, in which buffer and superconducting (REBa2Cu3O7-delta) layers are deposited epitaxially on a substrate, is well established in the research environment. However, obtaining uninterrupted deposition at high speed, increasing flexibility in composition and in film thickness and attaining independence of geometric constraints are areas in which many vacuum techniques will need sustained development in order to answer industrial demands. This work describes the deposition of textured CeO2 buffer layers based on sol gel dip coating under atmospheric environment and from aqueous precursor materials. Research has been performed towards the deposition of CeO2-buffer layers using the amorphous citrate method on sapphire substrates and Ni-W foils. Coating is performed using the dip-coating technique, which allows extension to a continuous system. The withdrawal speed and the thermal treatment have been optimised in order to obtain highly oriented (001) layers exhibiting a smooth and crack-free morphology both on ceramic and metallic substrates, From the results it was concluded that sintering atmosphere and sintering temperature play a crucial role in the growth mechanism. This study describes the structural and morphological analysis of the thin layer with special attention to the difference between ceramic and metallic substrates

Lire un dossier de documents à visée informative et y circuler : un « objet enseignable » au début du secondaire ?

Cet article présente quelques premiers résultats issus d’une recherche quasi expérimentale et longitudinale qui porte sur l’enseignement explicite des pratiques de lecture et d’écriture des textes informatifs requises pour réussir à l’école. Après avoir déplié quelques constats liés au caractère hétérogène et composite des supports largement utilisés dans la sphère scolaire et quelques obstacles relatifs aux changements des pratiques pédagogiques, nous faisons porter notre réflexion sur l’examen de productions d’élèves et de verbalisations d’enseignants de première année du secondaire. Ces traces écrites et témoignages seront analysés au regard de la mise en œuvre d’un premier module d’apprentissage, « Se familiariser avec les usages des écrits à visée informative, explicative, justificative ». L’étude met en évidence quelques leviers susceptibles de favoriser des pratiques de classe adaptées aux difficultés posées par les documents informatifs et par les tâches soumises à leur propos.This article presents the early results of a quasi-experimental and longitudinal research on the teaching practice of reading and writing informative texts and the related skills needed to succeed in school. Some findings about frequently used supports in the Belgian public school system will be explained. Those supports for informative texts are characterized by a versatility of form, which brings some difficulties for the students. Obstacles in changing the pedagogical practice of teachers will also be discussed. The research will reflect upon the data collected before and after a sequence of lessons implemented in classes of first-year secondary students (12-13 year olds) and the related speech of teachers. The title of this sequence is: “Getting to know the use of informative explanatory and justifiable texts”. Based on these findings, the study highlights some approaches to promote good classroom practices