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Author: angela hight walker

Displaying records 11 to 20 of 72 records.
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11. Multimodal, Nanoscale, Hyperspectral Imaging Demonstrated on Heterostructures of Quantum Dots and DNA-Wrapped Single-Wall Carbon Nanotubes
Published: 10/21/2009
Authors: Hyeong G. Kang, Matthew Lawrence Clarke, Jianyong Tang, John Taylor Woodward IV, Shin G Chou, Zhenping Zhou, Angela R Hight Walker, Tinh Nguyen, Jeeseong Hwang
Abstract: A multimodality imaging technique integrating atomic force, polarized Raman, and fluorescence lifetime microscopy and a 2D autocorrelation image analysis is applied to study the properties of a mesoscopic heterostucture of nanoscale materials. This ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=902938

12. Probing the Growth and Aging of Colloidal Cobalt Nanoparticles
Published: 6/11/2009
Authors: Guangjun Cheng, Cindi L Dennis, Robert D Shull, Angela R Hight Walker
Abstract: We have combined transmission electron microscopy (TEM) and magnetic measurements to characterize the growth of colloidal cobalt (Co) nanoparticles during synthesis and their subsequent stability in air. During the growth, TEM measurements have shown ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=842608

13. Dipolar Chains formed by synthesized cobalt nanocubes
Published: 5/11/2009
Authors: Guangjun Cheng, Robert D Shull, Angela R Hight Walker
Abstract: Cobalt nanocubes with an average edge length of 50 nm and the epsilon crystalline structure were synthesized via thermo-decomposition in 1,2-dichlorobenzene at 120 oC in the presence of the surfactants. These nanocubes form dipolar chains upon drying ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=842508

14. Towards optimization and characterization of dye-embedded gold nanoclusters for multiplexed optical imaging
Published: 2/26/2009
Authors: Michael A. McDonald, Angela R Hight Walker
Abstract: Metallic nanoparticle aggregates coupling strong surface plasmons with a Raman reporter molecule have been developed for application in multiplexed optical imaging. Of interest to our work is the ability of the agents to serve as surface-enhanced Ram ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=901384

15. Transmission electron microscopy characterization of colloidal copper nanoparticles and their chemical reactivity
Published: 2/16/2009
Authors: Guangjun Cheng, Angela R Hight Walker
Abstract: A colloidal synthesis route was developed to produce face-centered cubic (fcc) copper (Cu) nanoparticles in the presence of the surfactants in an organic solvent under an argon environment. Various synthetic conditions have been explored to control t ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=903450

16. Centrifugal Length Separation of Carbon Nanotubes
Published: 10/1/2008
Authors: Jeffrey A Fagan, Matthew Becker, Jae H. Chun, Barry J. Bauer, Jeffrey Ray Simpson, Angela R Hight Walker, Erik K. Hobbie
Abstract: Separation of single wall carbon nanotubes (SWCNTs) by length via centrifugation in a high density medium, and the characterization of both the separated fractions and the centrifugation process are presented. Significant quantities of the separated ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=853635

17. Surface-Enhanced Raman Spectroscopy via Gold Nanostars
Published: 9/28/2008
Authors: Emren Nalbant-Esenturk, Angela R Hight Walker
Abstract: Anisotropic metallic nanoparticles have unique optical properties, which lend them to applications such as Surface Enhanced Raman Spectroscopy (SERS). Branched and star-shaped gold nanoparticles have been prepared in aqueous phase by seed-mediated gr ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=841139

18. Origin of the exceptional negative thermal expansion in metal-organic framework-5 Zn^d4^O(1,4-benzenedicarboxylate)^d3
Published: 8/1/2008
Authors: Wei Zhou, Hui Wu, Taner Yildirim, Jeffrey Ray Simpson, Angela R Hight Walker
Abstract: Metal-organic framework-5 (MOF-5) was recently suggested to possess an exceptionally large negative thermal expansion coefficient. Our direct experimental measurement of the thermal expansion of MOF-5, using neutron powder diffraction, in the tempe ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=610032

19. Influence of the Colloidal Environment on the Magnetic Behavior of Cobalt Nanoparticles
Published: 11/6/2007
Authors: Guangjun Cheng, Cindi L Dennis, Robert D Shull, Angela R Hight Walker
Abstract: The magnetic properties of 10 nm cobalt (Co) nanoparticles in 1,2-dicholorbenenze (DCB) are investigated via a series of magnetization (M) vs. temperature (T) measurements. A rapid rise in magnetization around 250 K during warming and a sudden drop a ...
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=841084

20. The Influence of Temperature on the Magnetic Behavior of Collodial Cobalt Nanoparticles
Published: 6/7/2007
Authors: Cindi L Dennis, Brian B. Maranville, Angela R Hight Walker, Robert D Shull
http://www.nist.gov/manuscript-publication-search.cfm?pub_id=901755