The structure of gauge-invariant ideals of labelled graph C∗C^*-algebras

In this paper, we consider the gauge-invariant ideal structure of a $C^*$-algebra $C^*(E,\mathcal{L},\mathcal{B})$ associated to a set-finite, receiver set-finite and weakly left-resolving labelled space $(E,\mathcal{L},\mathcal{B})$, where $\mathcal{L}$ is a labelling map assigning an alphabet to each edge of the directed graph $E$ with no sinks. Under the assumption that an accommodating set $\mathcal{B}$ is closed under taking relative complement, it is obtained that there is a one to one correspondence between the set of all hereditary saturated subsets of $\mathcal{B}$ and the gauge-invariant ideals of $C^*(E,\mathcal{L},\mathcal{B})$. For this, we introduce a quotient labelled space $(E,\mathcal{L},[\mathcal{B}]_R)$ arising from an equivalence relation $\sim_R$ on $\mathcal{B}$ and show the existence of the $C^*$-algebra $C^*(E,\mathcal{L},[\mathcal{B}]_R)$ generated by a universal representation of $(E,\mathcal{L},[\mathcal{B}]_R)$. Also the gauge-invariant uniqueness theorem for $C^*(E,\mathcal{L},[\mathcal{B}]_R)$ is obtained. For simple labelled graph $C^*$-algebras $C^*(E,\mathcal{L},\bar{\mathcal{E}})$, where $\bar{\mathcal{E}}$ is the smallest accommodating set containing all the generalized vertices, it is observed that if for each vertex $v$ of $E$, a generalized vertex $[v]_l$ is finite for some $l$, then $C^*(E,\mathcal{L},\bar{\mathcal{E}})$ is simple if and only if $(E,\mathcal{L},\bar{\mathcal{E}})$ is strongly cofinal and disagreeable. This is done by examining the merged labelled graph $(F,\mathcal{L}_F)$ of $(E,\mathcal{L})$ and the common properties that $C^*(E,\mathcal{L},\bar{\mathcal{E}})$ and $C^*(F,\mathcal{L},\bar{\mathcal{F}})$ share

Learner Needs Analysis for T&I Program Reform

This paper attempts to reflect learners’ perspectives of the program in a program reform through learner needs analysis that is often neglected in the practice of program renewal. It uses a questionnaire survey conducted with both current and past students of the program to investigate the learners’ target markets and areas of work, checking if the current content of teaching can prepare the learners for such target situations. It also looks into the results of the needs analysis for any discrepancy between the needs ‘perceived by the teachers’ and the ones ‘felt by the learners’. Based on the results of such analysis, a program renewal is proposed to better coordinate the interests and views of the parties involved in the teaching and learning.Cette communication vise à prendre en compte les perspectives des étudiants dans le cadre de la réforme de programmes de traduction et d’interprétation par le biais d’une analyse des besoins des étudiants, fait souvent négligé lors de la mise en pratique de la reconstitution d’un programme. Elle se sert d’un sondage au moyen d’un questionnaire auprès à la fois d’étudiants actuels et anciens, en vue d’examiner leurs marchés cibles et domaines de travail, pour vérifier si le contenu actuel des programmes d’enseignement est à même de préparer les apprenants à aborder de telles situations ciblées. Cette communication examine également les résultats de l’analyse des besoins afin de découvrir tout écart entre les besoins « perçus par les enseignants et ceux « ressentis par les apprenants ». En se basant sur les résultats d’une telle analyse, un renouvellement des programmes est proposé afin de mieux coordonner les intérêts et points de vue des parties prenantes, tant en matière d’enseignement que d’apprentissage

Au-SN Flip-Chip Solder Bump for Microelectronic and Optoelectronic Applications

As an alternative to the time-consuming solder pre-forms and pastes currently used, a co-electroplating method of eutectic Au-Sn alloy was used in this study. Using a co-electroplating process, it was possible to plate the Au-Sn solder directly onto a wafer at or near the eutectic composition from a single solution. Two distinct phases, Au5Sn and AuSn, were deposited at a composition of 30at.%Sn. The Au-Sn flip-chip joints were formed at 300 and 400 degrees without using any flux. In the case where the samples were reflowed at 300 degrees, only an (Au,Ni)3Sn2 IMC layer formed at the interface between the Au-Sn solder and Ni UBM. On the other hand, two IMC layers, (Au,Ni)3Sn2 and (Au,Ni)3Sn, were found at the interfaces of the samples reflowed at 400 degrees. As the reflow time increased, the thickness of the (Au,Ni)3Sn2 and (Au,Ni)3Sn IMC layers formed at the interface increased and the eutectic lamellae in the bulk solder coarsened.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions