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Displaying 751 - 775 of 882

Influence of surface energy and relative humidity on AFM nanomechanical contact stiffness

March 9, 2006
Author(s)
Donna C. Hurley, Malgorzata Kopycinska-Mueller, D Julthongpiput, Michael J. Fasolka
The effects of surface functionality and relative humidity (RH) on nanomechanical properties were investigated using atomic force acoustic microscopy (AFAM), a contact scanned probe microscopy (SPM) technique. Self-assembled monolayers (SAMs) with

Consistency of D 13 C Measurements Improved

February 1, 2006
Author(s)
T B. Copelen, W Brand, M Gehre, M Groening, HAJ Meijer, Blaza Toman, R. Michael Verkouteren
We present state-of-the-art measurements and data evaluation methods to show that the consistency of carbon isotope ratio measurements can be improved 39 % to 47 % by anchoring the measurement scale with two isotopic reference materials differing in carbon

Polycyclic Aromatic Hydrocarbons in Flames, in Diesel Fuels, and in Diesel Emissions

December 1, 2005
Author(s)
R Dobbins, Robert A. Fletcher, Bruce A. Benner Jr., S Hoeft
Numerous chemical analyses of gaseous and particulate samples from laboratory flames provide a library of data on the polycyclic aromatic hydrocarbons (PAH) species found in diverse flame types burning fuels consisting of pure gaseous hydrocarbons. Diesel

Direct Preparation of Particles From Liquid Suspension for ESEM or SEM Analysis

October 1, 2005
Author(s)
Scott A. Wight, Richard D. Holbrook
A simplified method for the preparation of particles from liquid suspensions has been developed. Particles are deposited directly on carbon planchets for rapid analysis by environmental scanning electron microscopy or by conventional scanning electron

IMS-Based Trace Explosives Detectors for First Responder Use

September 1, 2005
Author(s)
Jennifer R. Verkouteren, John G. Gillen, R M. Verkouteren, Robert A. Fletcher, E S. Etz, George A. Klouda, Alim A. Fatah, Philip J. Mattson
The purpose of this document is to establish minimum performance requirements and an associated test method for Ion Mobility Spectrometry (IMS) based trace explosives detectors for use by the first responder community. Information concerning the theory and

Contact mechanics and tip shape in afm-based nanomechanical measurements

August 31, 2005
Author(s)
Malgorzata Kopycinska-Mueller, Roy H. Geiss, Donna C. Hurley
Stiffness-load curves obtained in quantitative atomic force acoustic microscopy (AFAM) measurements depend on both the elastic properties of the sample and the geometry of the atomic force microscope (AFM) tip. The geometry of silicon AFM tips changes when

Miniature Piezoceramic Actuators with Improved Fatigue Resistance

June 1, 2005
Author(s)
Stephanie A. Hooker, Jens Mueller, Clayton Kostelecky, K. Womer
Piezoelectric ceramics are desirable actuator materials for many biomedical applications due to their ability to generate precise, controlled motion with applied voltage. Herein, we report the fabrication of miniature piezoelectric ceramic actuators and

Acoustical methods to determine thin-film and nanoscale mechanical properties

May 31, 2005
Author(s)
Donna C. Hurley, Roy H. Geiss, N Jennett, Malgorzata Kopycinska-Mueller, A Maxwell, Jens Mueller, David T. Read, J Wright
We describe two acoustical methods to evaluate the mechanical properties of thin films and nanoscale structures: atomic force acoustic microscopy and surface acoustic wave spectroscopy. The elastic properties of an 800-nm-thick nickel film were examined

In Situ Ellipsometric Study of PEG/Cl - Coadsorption on Cu, Ag, and Au

May 1, 2005
Author(s)
Marlon L. Walker, Lee J. Richter, Thomas P. Moffat
Spectroscopic ellipsometry was used to examine the adsorption of polyethylene glycol (PEG) and Cl- on polycrystalline Cu, Ag and Au electrodes in sulfuric acid. In halide-free sulfuric acid, PEG adsorption on Cu and Ag is minimal at potentials positive of

Nanometrology - FY 2004 Programs and Selected Accomplishments

April 15, 2005
Author(s)
C M. Allocca
The MSEL Nanometrology Program incorporates basic measurement metrologies to determine material properties, process monitoring at the nanoscale, nano-manufacturing and fabrication techniques, and structural characterization and analysis techniques, such as

Elastic-property measurements of ultrathin films using atomic force acoustic microscopy

April 5, 2005
Author(s)
Malgorzata Kopycinska-Mueller, Roy H. Geiss, Jens Mueller, Donna C. Hurley
Atomic force acoustic microscopy (AFAM), an emerging technique that affords nanoscale lateral and depth resolution, was employed to measure the elastic properties of ultrathin films. In this study we measured the indentation modulus M of three nickel films

Influence of Tip Wear on Atomic Force Acoustic Microscopy Experiments

January 31, 2005
Author(s)
Malgorzata Kopycinska-Mueller, Roy H. Geiss, Paul Rice, Donna C. Hurley
Tip wear and its corresponding change in geometry is a major impediment for quantifying atomic force acoustic microscopy (AFAM). To better understand the process of tip wear and its influence on AFAM measurements of material elastic properties, we have

Polycyclic Aromatic Hydrocarbons in Flames, in Diesel Fuels, and in Diesel Emissions

January 1, 2005
Author(s)
Robert A. Fletcher, R Dobbins, Bruce A. Benner Jr, S Hoeft
Diesel fuels and emissions are composed of numerous hydrocarbon species. Combustion generated or pyrogenic polycyclic aromatic hydrocarbons (PAHs) derived from premixed and diffusion flames often consists of the most stable benzenoid PAHs. In contrast

Nanoscale Elastic-Property Mapping with Contact-Resonance-Frequency AFM

December 31, 2004
Author(s)
Donna C. Hurley, Tony B. Kos, Paul Rice
We describe dynamic atomic force microscopy (AFM) techniques to map the nanoscale elastic properties of surfaces, thin films, and nanostructures. Our approach is based on atomic force acoustic microscopy (AFAM) methods that have previously been used for

Standardization of Isotope Ratio Measurements for Doping Control

December 1, 2004
Author(s)
R M. Verkouteren
Pharmaceutical steroids are known to differ in isotopic composition from those produced naturally in the body. By measuring the 13 C/ 12C ratio of specific steroids deteched in urine, the technique of Gas Chromatography-Combustion-Isotope Ratio Mass
Displaying 751 - 775 of 882