The effect of a computerized morpheme-based training procedure on the reading and writing skills of reading-disabled participants (N = 30, mean age = 11.23 years, SD = 0.935) was examined. Considering that fast morphological analysis has been found to have a central role in written word processing of skilled readers, the following training was designed to enhance this process: it consisted of a visual lexical-decision task in which morphologically complex words were visually presented while the duration of the word-stems’ presentation was gradually restricted. A control intervention consisted of the same task, except that the duration of a nonmorphological unit’s presentation was manipulated. The children were divided into two groups: one underwent the morpheme-based intervention, and the other underwent the control intervention. The morpheme-based training procedure had a positive effect beyond that of the control procedure on the spelling of untrained word stems embedded in trained prefixes and suffixes. These results suggest a general improvement in retrieval of orthographic–morphological representations in spelling. Improvements in other measures could, however, not be ascribed to the morphological manipulation alone. These results emphasize the link between morphological processing and spelling. However, the morpheme-based training procedure appears to be less relevant to the improvement of reading.

We validate a new law for the aspect ratio of vortices in a rotating, stratified flow, where and are the vertical half-height and horizontal length scale of the vortices. The aspect ratio depends not only on the Coriolis parameter and buoyancy (or Brunt–Väisälä) frequency of the background flow, but also on the buoyancy frequency within the vortex and on the Rossby number of the vortex, such that . This law for is obeyed precisely by the exact equilibrium solution of the inviscid Boussinesq equations that we show to be a useful model of our laboratory vortices. The law is valid for both cyclones and anticyclones. Our anticyclones are generated by injecting fluid into a rotating tank filled with linearly stratified salt water. In one set of experiments, the vortices viscously decay while obeying our law for , which decreases over time. In a second set of experiments, the vortices are sustained by a slow continuous injection. They evolve more slowly and have larger while still obeying our law for . The law for is not only validated by our experiments, but is also shown to be consistent with observations of the aspect ratios of Atlantic meddies and Jupiter’s Great Red Spot and Oval BA. The relationship for is derived and examined numerically in a companion paper by Hassanzadeh, Marcus & Le Gal (J. Fluid Mech., vol. 706, 2012, pp. 46–57).

We report on the incorporation of molybdenum into tungsten oxide by co-sputtering and its effect on solar-powered photoelectrochemical (PEC) water splitting. Our study shows that Mo incorporation in the bulk of the film (WO3:Mo) results in poor PEC performance when compared with pure WO3, most likely due to defects that trap photo-generated charge carriers. However, when a WO3:Mo/WO3 bilayer electrode is used, a 20% increase of the photocurrent density at 1.6 V versus saturated calomel reference electrode is observed compared with pure WO3. Morphological and microstructural analysis of the WO3:Mo/WO3 bilayer structure reveals that it is formed by coherent growth of the WO3:Mo top layer on the WO3 bottom layer. This effect allows an optimization of the electronic surface structure of the electrode while maintaining good crystallographic properties in the bulk.

We report on the development of tungsten-oxide-based photoelectrochemical (PEC) water-splitting electrodes using surface modification techniques. The effect of molybdenum incorporation into the WO3 bulk or the surface region of the film is discussed. Our data indicate that Mo incorporation in the entire film (WO3:Mo) results in poor PEC performances, most likely due to defects that trap photo-generated charge carriers. However, compared to a pure WO3 (WO3:Mo)-based PEC electrode, a 20% (100%) increase of the photocurrent density at 1.6 V vs. SCE is observed if the Mo incorporation is limited to the near-surface region of the WO3 film. The resulting WO3:Mo/WO3 bilayer structure is formed by epitaxial growth of the WO3:Mo top layer on the WO3 bottom layer, which allows an optimization of the electronic structure induced by Mo incorporation while maintaining good crystallographic properties.

Self-assembled monolayers of fluorinated thiols have been used as a means of surface conditioning to modify the work function of polycrystalline, wide-gap, chalcopyrite thin films. The molecular dipole, characteristic of such polar molecules, could be transferred to the surface of the semiconductor. Self-arrangement and orientation of the molecules upon adsorption ensured a net dipole contribution that was observed by means of ultra-violet photoemission spectroscopy. Such an approach offers a simple way for interface engineering, with a potential impact on the design of compound-specific band alignments of chalcopyrite-based devices. Molecular mechanics calculations of the expected molecular geometries complemented this work.

The “roll-over” phenomenon in current-voltage (J-V) curves of CdS/CdTe devices is recognized as a result of the formation of a higher back barrier. When Cu has not been intentionally added to the back contact, roll-over is understandable. However, the mechanism was unclear for forming J-V roll-over in a CdTe cell with a back contact containing Cu. We did extensive characterizations, including XRD, XPS, SIMS, TEM, and EDS, and “recontact” experiments to understand this phenomenon. The results show that the roll-over comes from the formation of Cu-related oxides at the back side of the device during processing, rather than the diffusion of Cu to the front side of the device. Discussions related to the J-V roll-over mechanisms will also be presented.

In this paper we describe synchrotron based, state-of-the-art spectroscopic methods for the analysis of surfaces and interfaces in thin film photovoltaic devices, their merits and their limitations. Using results obtained with the “CISSY” end station at the BESSY synchrotron in Berlin, Germany, we show how surface sensitive Synchrotron excited X-ray Photoelectron Spectroscopy (SXPS) and Soft X-ray Emission Spectroscopy (SXES), which yields compositional and chemical depth information in the ten to hundred nm scale, have increased our knowledge of the chemistry of surfaces and buried interfaces of these systems.