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Title: Nanoparticles shape size composition and more.


Abstract not provided.

Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Resource Relation:
Conference: Proposed for presentation at the National Institute for Nano-Engineering (NINE) Topical Meeting on NanoMaterials Manufacturing held May 8, 2007 in Albuquerque, NM.
Country of Publication:
United States

Citation Formats

Boyle, Timothy J. Nanoparticles shape size composition and more.. United States: N. p., 2007. Web.
Boyle, Timothy J. Nanoparticles shape size composition and more.. United States.
Boyle, Timothy J. Tue . "Nanoparticles shape size composition and more.". United States. doi:.
title = {Nanoparticles shape size composition and more.},
author = {Boyle, Timothy J.},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2007},
month = {Tue May 01 00:00:00 EDT 2007}

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  • In this paper the results from a detailed XAFS characterization of supported rhenium nanoparticles are presented. The Re nanoparticles are formed by the reduction of dispersed supported rhenium oxide in the presence of moist hydrogen. The shape of the wet-reduced Re clusters is determined by comparing the EXAFS spectra of Re-metal to the Re-wet-reduced clusters to 6 {angstrom}. A decrease in the signal from the 4th and 7th Re shells is an indication of sheet-like rather than spherical-like particles.
  • A common misconception is that as size decreases, quartz grains become progressively more angular. All possible size/shape relationships can and do occur including: 1) no relationship, 2) fine sizes, more rounded, 3) finer sized more angular, and 4) size/shape discontinuities where shape is constant over a wide range and then changes and stays constant over the remaining range. Detritus from large, long established flood plains (Mississippi, Ganges, Amazon) display a continuous change in shape with size. Detritus from primary sources generally display no size/shape effect. Small rivers commonly exhibit size/shape discontinuities. The origin of a particular size/shape relationship arises frommore » two opposing tendencies. Finer detritus travel much faster than coarser sands. Thus silts from one provenance can overtake coarser material of different provenance. If flood plains are large and long-lived, the contribution of individual tributaries is diluted almost to indetectibility and all sizes have time enough to reach the sea. In such situations the size/shape relationship reflects a steady state of equilibrium. In smaller rivers individual tributaries can provide significant proportions of grains to flood plains with characteristic sizes and shapes leading to discrete shifts in the size/shape curve.« less
  • In automobile emissions control, it has been of great importance to develop catalysts which have good thermal stability and high NO{sub x} conversion. To achieve this goal, it is crucially important to understand the behavior of metal particles and supports in engine exhaust gas. The authors have newly developed a medium-energy ion scattering (MEIS) simulation program for the analysis of alloy nanoparticles. The program was applied to the composition and average particle size analysis of Pt-Rh/{alpha}-Al{sub 2}O{sub 3} treated in oxidative and reductive atmospheres. It was found that the Pt concentration near the surface decreased after oxidative treatment at 800more » C and returned to its original value after reductive treatment at the same temperature. It was shown that Pt particle average sizes less than 10 nm can be evaluated quantitatively. Also, this technique gives some insight into particle size distribution in the initial stage of particle sintering, which has been quite out of the reach of conventional analytical tools.« less
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