Simple Phosphinate Ligands Access New Zinc Clusters Identified in the Synthesis of Zinc Oxide Nanoparticles

The bottom-up synthesis of ligand-stabilised functional nanoparticles from molecular precursors is widely applied but difficult to study mechanistically. Here, we use 31P NMR spectroscopy to follow the trajectory of phosphinate ligands during the synthesis of a range of new ligated zinc oxo clusters, containing 4, 6 and 11 zinc atoms. Using an organometallic route, the clusters interconvert rapidly, and self-assemble in solution based on thermodynamic equilibria, rather than nucleation kinetics. These clusters are also identified, in situ, during the synthesis of phosphinate-capped zinc oxide nanoparticles. Unexpectedly, the ligand is sequestered to a stable Zn11 cluster during the majority of the synthesis and only becomes coordinated to the nanoparticle surface, in the final step. As well as a versatile and accessible route to new (optionally doped) zinc clusters, the findings provide a new understanding of the role of well-defined molecular precursors during the synthesis of small (2-4 nm) nanoparticles

Vol. 7, No. 2

Contents: Police and Fire Interest Arbitration in Illinois, by Thomas F. Sonneborn Trends in Illinois Interest Arbitration, Carl S. Tominberg, Jane E. Shaffer Recent Developments, by the Student Editorial Board Further Referenceshttps://scholarship.kentlaw.iit.edu/iperr/1004/thumbnail.jp

Vol. 7, No. 2

Contents: Police and Fire Interest Arbitration in Illinois, by Thomas F. Sonneborn Trends in Illinois Interest Arbitration, Carl S. Tominberg, Jane E. Shaffer Recent Developments, by the Student Editorial Board Further Referenceshttps://scholarship.kentlaw.iit.edu/iperr/1004/thumbnail.jp

Safety, the Preface Paradox and Possible Worlds Semantics

This paper contains an argument to the effect that possible worlds semantics renders semantic knowledge impossible, no matter what ontological interpretation is given to possible worlds. The essential contention made is that possible worlds semantic knowledge is unsafe and this is shown by a parallel with the preface paradox

The challenge of changing deeply-held student beliefs about the relativity of simultaneity

Previous research indicates that after standard instruction students at all academic levels often construct a conceptual framework in which the ideas of absolute simultaneity and the relativity of simultaneity co-exist. This article describes the development and assessment of instructional materials intended to improve student understanding of the concept of time in special relativity, the relativity of simultaneity, and the role of observers in inertial reference frames. Results from pretests and post-tests are presented to demonstrate the effect of the curriculum in helping students deepen their understanding of these topics. Excerpts from taped interviews and classroom interactions help illustrate the intense cognitive conflict that students encounter as they are led to confront the incompatibility of their deeply-held beliefs about simultaneity with the results of special relativity.Comment: 17 pages, 6 figures, 2 tables, 27 references; Accepted for publication in Physics Education Research Section, American Journal of Physics (2001

Hierarchical carbon aerogel modified carbon fiber composites for structural power applications

The desire to reduce overall weight in devices is a key driver for perpetual material development; the ability to combine composites with energy storage functions/capabilities which simultaneously provide structural integrity has the potential to supersede monofunctional components. To achieve this ambition, the multifunctional structure must perform both mechanical and energy storage functions sufficiently, but often there is a trade off in performance which is a significant challenge to overcome. Carbon aerogels have been shown to contribute positively to (electro-chemical double layer) capacitive performance due to an increased surface area in multifunctional carbon fiber based composite electrodes, but have also been shown to reduce mechanical properties; the addition of nanoscale reinforcers, such as carbon nanotubes, graphene or alike, with their superlative electrical and mechanical properties are proposed to address these concerns and create a truly hierarchical structure suitable for structural power applications

1980 Missouri commercial strawberry spray schedule

"MP 266, 1/80, 1.5M