On the 3d electron contribution to the electronic structure of tetrahedral I–III–VI2 compounds

The reflectivity of single crystals of (CuInSe₂)_1?x(2ZnSe)_x which have the chalcopyrite structure for x ? 0.43 and the sphalerite structure for x ? 0.48 was measured. A band near 3 eV was observed for all compositions in the chalcopyrite structure but was not seen in the sphalerite phase. Its abrupt disappearance from x = 0.43 to x = 0.48 indicates that it may not be due to transitions from the copper d-levels to the lowest conduction band but may be associated with interband pseudo-direct transitions which become allowed by zone folding.     

Modelling the evaporation of thin films of colloidal suspensions using dynamical density functional theory

Recent experiments have shown that various structures may be formed during the evaporative dewetting of thin films of colloidal suspensions. Nanoparticle deposits of strongly branched 'flower-like', labyrinthine and network structures are observed. They are caused by the different transport processes and the rich phase behaviour of the system. We develop a model for the system, based on a dynamical density functional theory, which reproduces these structures. The model is employed to determine the influences of the solvent evaporation and of the diffusion of the colloidal particles and of the liquid over the surface. Finally, we investigate the conditions needed for 'liquid-particle' phase separation to occur and discuss its effect on the self-organized nanostructures.     

Examining Elementary School Science Achievement Gaps Using an Organizational and Leadership Perspective

There is the tendency to explain away successful urban schools as indicative of the heroic efforts by a tireless individual, effectively blaming schools that underperform for a lack of grit and dedication. This study reports the development of a research instrument (School Science Infrastructure, or SSI) and then applying that tool to an investigation of equitable science performance by elementary schools. Our efforts to develop a science‐specific instrument to explore associations between school‐level variables and equitable science performance are informed by James Coleman's tripartite notion of social capital: the “wealth” of organizations is encompassed within their social norms, informational channels, and reciprocating relationships. Grounded in school effectiveness research and social capital theory, the instrument that we report on here is a valid and reliable tool to support meso‐level investigations of factors contributing to school variations in science achievement.