Sister Mary Regina Donovan, S.S.J. (Nora Donovan)

Thin silicon dioxide layers (40-100 A) can be successfully produced by anodization of silicon in pure water. The resulting layers are very homogeneous and pinhole free. The monitoring of the SiO2 thickness is accurately achieved by simple coulometry. The electrical properties of the oxide layers and the associated Si/SiO2 interface have been investigated by forming metal-oxide-semiconductor (MOS) capacitors using the anodically grown oxide as the dielectric and aluminium or chromium as the metal. This investigation shows a low charge density at the Si/SiO2 interface (≤ 10 11 charges. cm-2) and an interface states density comparable to that obtained with thermally grown SiO2 (1011 cm -2eV-1). The dielectric breakdown occurs at high fields (11 to 14 MW . cm-1). These results show that there is no pollution during the electrolysis. Furthermore, the metal to oxide barrier heights remained high (2.5 to 2.8 eV) even for thin (44 A) SiO2 layers

First-Principles Study of the Band Gap Structure of Oxygen-Passivated Silicon Nanonets

A net-like nanostructure of silicon named silicon nanonet was designed and oxygen atoms were used to passivate the dangling bonds. First-principles calculation based on density functional theory with the generalized gradient approximation (GGA) were carried out to investigate the energy band gap structure of this special structure. The calculation results show that the indirect–direct band gap transition occurs when the nanonets are properly designed. This band gap transition is dominated by the passivation bonds, porosities as well as pore array distributions. It is also proved that Si–O–Si is an effective passivation bond which can change the band gap structure of the nanonets. These results provide another way to achieve a practical silicon-based light source

Les réformes agraires et les changements socio-économiques, politiques, culturels au sein du monde rural: bilan des expériences pour l'approche du cas de l'Algérie et de ses perspectives d'évolution. Contribution à une sociologie rurale; la paysannerie dans le développement économique et social

Doctorat en sciences sociales, politiques et économiquesinfo:eu-repo/semantics/nonPublishe

Estudio fisico-quimico y microbiologico de la fermentacion de aceitunas verdes arbequinas

A pesar del creciente consumo, existe poca información disponible sobre las aceitunas verdes en salmuera, sobre todo de la variedad Arbequina. Con este producto se suelen presentar problemas de conservación debido a su baja acidez y valores relativamente altos de pH. Se ha realizado un estudio comparativo, con aceituna Arbequina, de fermentación espontánea y de fermentación dirigida utilizando cepas de bacterias lácticas, aisladas de muestras comercializadas de estas olivas, que se han identificado en todos los casos como Lactobacillus plantarum. En el presente trabajo se ofrecen los resultados obtenidos en la determinación de los principales parámetros físico-químicos y microbiológicos de las aguas de lavado de las aceitunas y del caldo de fermentación a lo largo del proceso. A partir de los resultados expuestos se proponen algunos cambios significativos en la técnica usual para la fermentación de la aceituna verde Arbequina