Triple‐crystal x‐ray diffraction analysis of reactive ion etched gallium arsenide

This is the published version. Copyright 1994 American Institute of PhysicsThe effect of BCl3 reactive ion etching on the structural perfection of GaAs has been studied with diffuse x‐ray scattering measurementsconducted by high‐resolution triple‐crystal x‐ray diffraction. While using a symmetric 004 diffraction geometry revealed no discernible differences between etched and unetched samples, using the more surface‐sensitive and highly asymmetric 113 reflection revealed that the reactive ion etched samples etched displayed less diffusely scattered intensity than unetched samples, indicating a higher level of structural perfection. Increasing the reaction ion etch bias voltage was found to result in decreased diffuse scattering initially, until an apparent threshold voltage was reached, after which no further structural improvement was observed. Furthermore, we have shown that this reduction in process‐induced surfacestructural damage is not due merely to the removal of residual chemical‐mechanical polishing damage

Conversion of CO2 in a packed-bed dielectric barrier discharge reactor

The conversion of CO2 into CO and O2 in a quartz cylindrical packed-bed dielectric reactor has been studied using CO2 and Ar gas mixtures at atmospheric pressure and near ambient temperature with quartz wool, γ-Al2O3, and TiO2 packing. The highest energy efficiencies and conversion rates were observed with TiO2 packing in 20% CO2 in Ar: 30% conversion with 2.9% energy efficiency, and 17.5% conversion with 5.0% energy efficiency. Both γ-Al2O3 and quartz wool also showed an enhancement in conversion over an unpacked reactor. The percentage of CO2 to Ar in the range of 20%–60% is shown to have only a minor effect on reactor performance. Conversion as a function of power input and flow rate is studied in detail for γ-Al2O3 and TiO2 packing with similar particle sizes. In both cases, simple chemical kinetic models show that the CO production rate is nearly equal for both materials, while reverse reaction rates to CO2 are doubled for γ-Al2O3 compared to TiO2. From detailed charge–voltage (Q-V) analysis of all four reactor configurations, it is revealed that the electric field at which discharging occurs is higher for both γ-Al2O3 and TiO2 as compared to the empty or quartz wool filled reactors. Comparing kinetic model results with the electrical Q-V analysis, it appears likely that the higher and similar magnitude electric fields occurring with γ-Al2O3 and TiO2 are directly responsible for the increased CO production rates via increased electron energies in the discharge. The higher reverse reaction rates for γ-Al2O3, and its subsequent poorer performance compared to TiO2, can be attributed to a significantly higher effective surface area, which increases undesirable surface reactions between CO and oxygen species

Conversion of CO2 in a packed-bed dielectric barrier discharge reactor

The conversion of CO2 into CO and O2 in a quartz cylindrical packed-bed dielectric reactor has been studied using CO2 and Ar gas mixtures at atmospheric pressure and near ambient temperature with quartz wool, γ-Al2O3, and TiO2 packing. The highest energy efficiencies and conversion rates were observed with TiO2 packing in 20% CO2 in Ar: 30% conversion with 2.9% energy efficiency, and 17.5% conversion with 5.0% energy efficiency. Both γ-Al2O3 and quartz wool also showed an enhancement in conversion over an unpacked reactor. The percentage of CO2 to Ar in the range of 20%–60% is shown to have only a minor effect on reactor performance. Conversion as a function of power input and flow rate is studied in detail for γ-Al2O3 and TiO2 packing with similar particle sizes. In both cases, simple chemical kinetic models show that the CO production rate is nearly equal for both materials, while reverse reaction rates to CO2 are doubled for γ-Al2O3 compared to TiO2. From detailed charge–voltage (Q-V) analysis of all four reactor configurations, it is revealed that the electric field at which discharging occurs is higher for both γ-Al2O3 and TiO2 as compared to the empty or quartz wool filled reactors. Comparing kinetic model results with the electrical Q-V analysis, it appears likely that the higher and similar magnitude electric fields occurring with γ-Al2O3 and TiO2 are directly responsible for the increased CO production rates via increased electron energies in the discharge. The higher reverse reaction rates for γ-Al2O3, and its subsequent poorer performance compared to TiO2, can be attributed to a significantly higher effective surface area, which increases undesirable surface reactions between CO and oxygen species

Do psychology students command transversal competences? A case study

El desarrollo de las competencias transversales reclama su aplicación en contextos reales y plantea nuevos desafíos a la Educación Superior. Estas instituciones no sólo deben formar ciudadanos comprometidos con la mejora de la sociedad y contribuir a la creación del conocimiento, sino también establecer entre sus prioridades una buena relación con los sectores productivos, nichos naturales de inserción de sus titulados. De esta ecuación surgen nuevos interrogantes sobre cómo afecta la situación laboral del estudiante universitario en su aprendizaje. En concreto, este trabajo persigue conocer el dominio de las CT que presentan los estudiantes según su propia percepción, y contrastar estos resultados en función de su situación laboral. Para ello, se analiza la percepción de 55 estudiantes de último año del Grado en Psicología recogida a través de un cuestionario diseñado ad hoc. Los resultados revelan un dominio bastante mejorable de estas competencias, siendo la más adquirida el compromiso ético y la menos, el conocimiento de una lengua extranjera. Tras el contraste del dominio de dichas competencias con su situación laboral se aprecia, en general, que el dominio es mayor en aquellos estudiantes que se encuentran en activo, con diferencias significativas en la capacidad de adaptación y actitud emprendedora. A partir de estos resultados parece que los futuros graduados en Psicología están adquiriendo competencias esenciales para su ámbito profesional, si bien su grado de dominio reclama mayores medidas dirigidas a facilitar la conciliación estudio-trabajo y a mejorar los programas de prácticas externas.The development of transversal competences demands practice in real contexts and higher education needs to consider these new challenges. Not only are members of society committed to the social improvement and the contribution and creation of knowledge from university but also these institutions need a good connection with the job market (specifically where there are job market niches for graduates). From this complex equation new questions arise about how this relationship affects a student’s job situation and their university studies. Particularly, this paper aims to know the students’ command of these competences from their own perceptions and compare it with their job situation. To do this, this article collected the perceptions of 55 final year psychology students through an ad hoc questionnaire. The results not show satisfactory dominance of these competences although they can be improve. The highest dominance is ethical commitment and the least being the knowledge of another foreign language. After, it is contrasted to the dominance of those competences with their work situation. Generally, the dominance is higher in students who are working, with significant differences inadaptability and entrepreneurship; two competences that are part in the systemic category that establishes ANECA (2005) in their theoretical model of transversal competences. From these results, it seems that future psychology graduates have obtained skills that are essential to their careers, but their dominance of important competences demands greater measures to facilitate work-study reconciliation and improve internship programs