Análisis de errores fónicos en la producción del sistema vocálico de aprendices árabes de español (Nivel A1-A2)

Uno de los problemas con los que se encuentra a menudo un estudiante de cualquier L2 es el relacionado con la producción oral, más concretamente, con la pronunciación. Dependiendo de cuál sea la lengua materna resulta más sencillo (si comparte sonidos o son similares articulatoriamente) o más complejo (si posee rasgos característicos que no son propios de su lengua). Es, por tanto, uno de los apartados dentro del aprendizaje que es más costoso. En este trabajo me centraré en aquellos hablantes que tienen como L1 el árabe y que están adquiriendo E/LE en un estado inicial, es decir, en un nivel A1-A2. Como bien indica el título, se trata de un análisis de los errores fónicos en la producción exclusivamente del sistema vocálico. Cuando hablo de errores fónicos, me refiero a los errores fonológicos y los errores fonéticos que tengan en la producción. No tendré en cuenta fallos en la colocación del acento ya que se trata de un nivel inicial.Departamento de Lengua EspañolaGrado en Español: Lengua y Literatur

Tuneable molecular doping of corrugated graphene

Density functional theory (DFT) modeling of the physisorption of four different types of molecules (toluene, bromine dimmer, water and nitrogen dioxide) over and above graphene ripples has been performed. For all types of molecules changes of charge transfer and binding energies in respect to flat graphene is found. The changes in electronic structure of corrugated graphene and turn of {\pi}-orbitals of carbon atoms in combination with chemical structure of adsorbed molecules are proposed as the causes of difference with the perfect graphene case and variety of adsorption properties of different types of the molecules. Results of calculation suggest that the tops of the ripples are more attractive for large molecules and valley between ripples for small molecules. Stability of molecules on the ripples and energy barriers for migration over flat and corrugated graphene is also discussed.Comment: 15 pages, 5 figures, accepted in Surface Scienc

Wiring-up catalytically active metals in solution with sulfonated carbon nanotubes

Highly water soluble sulfonate MWCNTs were synthesized and could be used to facilitate the electron transfer between Pd and Cu in a Wacker-type oxidation in solution.United States. Army (Institute for Soldier Nanotechnologies at MIT, DAAD-19-02-0002

A versatile, solvent-free methodology for the functionalisation of carbon nanotubes

High temperature activation of carbon nanotubes (CNTs) provides a new and highly versatile functionalisation strategy. The reaction allows the attachment of a wide variety of functional species onto the nanotube surface at grafting ratios between 1-8 wt%, whilst maintaining the intrinsic properties of the untreated materials. The underlying, radical-based, reaction mechanism has been established by quenching experiments and EPR studies. The distribution of the functionalised sites has been investigated at. the microscopic scale using tagging reactions. The grafted products have been characterized by electron microscopy, thermal analysis (TGA), Raman spectroscopy, and inverse gas chromatography (IGC). The change in the CNT surface properties after grafting has been quantified in terms of dispersive and specific surface energies, and altered dispersibilities in a broad range of solvents. It is possible to carry out the reaction using gas phase reagents, providing a clean, efficient, and scalable methodology, relevant to a diverse range of applications