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Search Publications by: Andrew Dienstfrey (Fed)

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Displaying 76 - 100 of 108

Characterization of a Metafilm/Metasurface

June 1, 2009
Author(s)
Christopher L. Holloway, Andrew M. Dienstfrey, Edward E. Kuester
A metafilm (also referred to as a metasurface) is the surface equivalent of a metamaterial. More precisely, a metafilm is a surface distribution of suitably chosen electrically-small scatterers. Metafilms are becoming popular as an alternative to full

Analysis of ISCD-NIST Survey for Bone Health

April 1, 2009
Author(s)
Andrew M. Dienstfrey, Tammy L. Oreskovic, Herbert S. Bennett, Lawrence T. Hudson
In 2007, the National Institute of Standards and Technology and the International Society for Clinical Densitometry designed a survey to prioritize seven research and standardization action items intended to improve accuracy and cross-comparability of dual

ISCD-NIST DXA Survey: Preliminary Report

May 15, 2008
Author(s)
Andrew M. Dienstfrey, Tammy L. Oreskovic, Lawrence T. Hudson, Herbert S. Bennett
This article reports and discusses briefly the preliminary results from the recent International Society for Clinical Densitometry (ISCD)-National Institute of Standards and Technology (NIST) dual-energy x-ray absorptiometry (DXA) Survey. The 1074 Survey

Characterization of cell samples from measurements of spectroscopic scattering phase dispersion

January 19, 2007
Author(s)
Shellee D. Dyer, Lara Roberson, Shelley M. Etzel, Tasshi Dennis, Andrew Dienstfrey, Vadim Tsvankin, Wei Tan
We present spectroscopic swept-source optical coherence tomography (OCT) measurements of the phase-dispersion of cell samples. We have previously demonstrated that the phase of the scattered field is, in general, independent of the intensity, and both must

Standards and Measurements for Assessing Bone Health

December 1, 2006
Author(s)
Herbert S. Bennett, Andrew Dienstfrey, Thomas Fuerst, Lawrence T. Hudson, Tammy L. Oreskovic, John Shepherd
This paper reports and discusses the results of the recent ISCD-NIST USMS Workshop on Standards and Measurements for Assessing Bone Health. The purpose of the Workshop was to assess the status of efforts to standardize and compare results from dual-energy

Terminology for High-Speed Sampling-Oscilloscope Calibration

December 1, 2006
Author(s)
Dylan Williams, Tracy S. Clement, Paul D. Hale, Andrew Dienstfrey
We discuss procedures for calibrating high-speed sampling oscilloscopes at the National Institute of Standards and Technology, and the terminology associated with those calibrations. The discussion clarifies not only the calibration procedures, but how to

Spectroscopic phase-dispersion optical coherence tomography measurements of scattering phantoms

September 4, 2006
Author(s)
Shellee D. Dyer, Tasshi Dennis, Lara Roberson, Shelley M. Etzel, Thomas Germer, Andrew Dienstfrey
We demonstrate a novel technique to determine the size of Mie scatterers with high sensitivity. Our technique is based on spectral domain optical coherence tomography measurements of the phase dispersion that is induced by the scattering process. We use

Minimum-Phase Calibration of Sampling Oscilloscopes

August 15, 2006
Author(s)
Andrew M. Dienstfrey, Paul D. Hale, Darryl A. Keenan, Tracy S. Clement, Dylan F. Williams
We describe an algorithm for determining the minimum phase of a linear time-invariant response function from its magnitude. The procedure is based on Kramers Kronig relations in combination with auxiliary direct measurements of the desired phase response

Calibration of Sampling Oscilloscopes With High-Speed Photodiodes

August 1, 2006
Author(s)
Tracy S. Clement, Paul D. Hale, Dylan Williams, C. M. Wang, Andrew Dienstfrey, Darryl A. Keenan
We calibrate the magnitude and phase response of equivalent-time sampling oscilloscopes to 110 GHz. We use a photodiode that has been calibrated with our electrooptic sampling system as a reference input pulse source to the sampling oscilloscope. We

Minimum-phase calibration of sampling oscilloscopes

August 1, 2006
Author(s)
Andrew Dienstfrey, Paul D. Hale, Darryl A. Keenan, Tracy S. Clement, Dylan Williams
We describe an algorithm for determining the minimum phase of a linear, time-invariant response function from its magnitude. The procedure is based on Kramers-Kronig relations in combination with auxiliary direct measurements of the desired phase response