Insulator-to-metal transition of SrTiO3:Nb single crystal surfaces induced by Ar+ bombardment

In this paper, the effect of Ar+ bombardment of SrTiO3:Nb surface layers is investigated on the macro- and nanoscale using surface-sensitive methods. After bombardment, the stoichiometry and electronic structure are changed distinctly leading to an insulator-to-metal transition related to the change of the Ti "d" electron from d0 to d1 and d2. During bombardment, conducting islands are formed on the surface. The induced metallic state is not stable and can be reversed due to a redox process by external oxidation and even by self-reoxidation upon heating the sample to temperatures of 300{\deg}C.Comment: 4 pages, 4 figure

Five Good Reasons for Engineering as the Focus for Technology Education

The article presents information on a paper which discusses why engineering design should be the focus for technology education. Technology education is still viewed as a non-essential instructional program and this is because school administrators and counselors have inadequate understanding of it. Even general populace have inadequate understanding concerning technology education. The pervasiveness of technology literally affects every living creature in our society. Therefore, it is of critical importance that the educational system includes and supports the study of technology in the general curricula. The deficiency within the technology education profession to formulate a clear and defined target for the curriculum that has both an understood goal and value. According to the author by organizing the technology education high school curriculum around the study of engineering design, the goal of technological literacy can be attained. Engineering design is more understood and valued than technology education by the general populace and it elevates the field of technology education to higher academic and technological levels. It also provides a solid framework to design and organize curriculum

Variation in foliar nitrogen and albedo in response to nitrogen fertilization and elevated carbon dioxide

It has recently been demonstrated that foliar nitrogen is positively correlated with surface albedo over a broad range of plant functional types. However, the mechanism(s) driving the nitrogen-albedo relationship remain elusive. This study investigated leaf spectral properties from three deciduous species subjected to either nitrogen or CO2 fertilization and compared results to measured chemical and structural properties. We measured reflectance and transmittance, foliar nitrogen, leaf mass per unit area, water content, and d13C values for stacks of 1, 2, 4, and 8 leaves. Nitrogen was the best predictor of leaf-level albedo of the traits that we measured. There were no significant differences in albedo between CO2 or nitrogen treatments. Across all species there was a negative relationship between albedo and foliar nitrogen, suggesting that the previously observed nitrogen-albedo relationship is not caused by leaf-level interactions, but is likely due to structural properties at the canopy or stand level