High-Accuracy X-Ray Diffraction Analysis of Phase Evolution Sequence During Devitrification of Cu50Zr50 Metallic Glass

Real-time high-energy X-ray diffraction (HEXRD) was used to investigate the crystallization kinetics and phase selection sequence for constant-heating-rate devitrification of fully amorphous Cu50Zr50, using heating rates from 10 K/min to 60 K/min (10 °C/min to 60 °C/min). In situ HEXRD patterns were obtained by the constant-rate heating of melt-spun ribbons under synchrotron radiation. High-accuracy phase identification and quantitative assessment of phase fraction evolution though the duration of the observed transformations were performed using a Rietveld refinement method. Results for 10 K/min (10 °C/min) heating show the apparent simultaneous formation of three phases, orthorhombic Cu10Zr7, tetragonal CuZr2 (C11b), and cubic CuZr (B2), at 706 K (433 °C), followed immediately by the dissolution of the CuZr (B2) phase upon continued heating to 789 K (516 °C). Continued heating results in reprecipitation of the CuZr (B2) phase at 1002 K (729 °C), with the material transforming completely to CuZr (B2) by 1045 K (772 °C). The Cu5Zr8 phase, previously reported to be a devitrification product in C50Zr50, was not observed in the present study

La poésie de Jakob van Hoddis ou la déstabilisation du sujet

Glimois Kristell. La poésie de Jakob van Hoddis ou la déstabilisation du sujet. In: Cahiers d'Études Germaniques, numéro 38, 2000/1. Qui parle dans le texte ? pp. 53-66

From Structured Input to Purposeful Output

This Finestra presents a pedagogical technique called Structured Input, which is designed to help second language learners make form-meaning connections from grammatical forms in the input they are exposed to. In this article, I will first outline the major theoretical principles that informed the development of Structured Input as an instructional technique. I will then demonstrate how to design Structured Input activities for the communicative language classroom, thereby providing ready-to-use activities for a grammar unit on the imparfait/passé composé distinction meant to enable learners to talk about past professional experiences as they prepare for a job interview in French