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Search Publications

NIST Authors in Bold

Displaying 24701 - 24725 of 73969

Trapping and Release of Citrate-Capped Gold Nanoparticles

August 1, 2011
Author(s)
Darwin R. Reyes-Hernandez, Geraldine I. Mijares, Brian J. Nablo, Kimberly A. Briggman, Michael Gaitan
An electrical method to trap and release charged gold nanoparticles on and from the surface of alkanethiol self-assembled-monolayer (SAM) modified gold electrodes is presented. Gold nanoparticle (GNP) coated electrodes were formed by immersing amine

A Bayesian Statistical Model for Hybrid Metrology to Improve Measurement Accuracy

July 31, 2011
Author(s)
Richard M. Silver, Nien F. Zhang, Bryan M. Barnes, Jing Qin, Hui Zhou, Ronald G. Dixson
We present a method to combine measurements from different techniques that reduces uncertainties and can improve measurement throughput. The approach directly integrates the measurement analysis of multiple techniques that can include different

Comparing Room Temperature and Cryogenic Cesium Fountains

July 31, 2011
Author(s)
Steven R. Jefferts, Thomas P. Heavner, Thomas E. Parker, Jon H. Shirley, Elizabeth A. Donley, Filippo Levi, Davide Calonico, C Calosso, Giovanni Costanzo, B. Mongino
We have compared the frequency of a room temperature cesium fountain primary frequency standard with that of a cryogenic (~80K) cesium fountain. This comparison yields a measurement of the blackbody frequency shift of the room temperature fountain.

Coordinating GPS Calibrations Among NIST, NRL, USNO, PTB, and OP

July 31, 2011
Author(s)
Marc A. Weiss, Victor S. Zhang, J White, K Senior, Demetrios Matsakis, S. Mitchell, P Uhrich, D Valat, W Lewandowski, G. Petit, Andreas Bauch, T. Feldman, A. Proia
Reviewing calibration results over the history since early 1980’s among several labs shows very mixed results. The best stabilities of receivers, as given by calibrations, are of the order of a few ns or better over a year, though many results are quite a

Improving the stability and accuracy of the Yb optical lattice clock

July 31, 2011
Author(s)
Andrew D. Ludlow, Yanyi Jiang, Nathan D. Lemke, Jeffrey A. Sherman, J. von Stecher, Richard W. Fox, Long-Sheng Ma, A.M. Rey, Christopher W. Oates
We report results for improving the stability and uncertainty of the NIST $^{171}$Yb lattice clock. The stability improvements derive from a significant reduction of the optical Dick effect, while the uncertainty improvements focus on improved

Limited Live-time Measurements of Frequency Spectra

July 31, 2011
Author(s)
David A. Howe, Neil Ashby, Danielle G. Lirette, Archita Hati, Craig W. Nelson
Frequency-difference-of-arrival (FDOA) can be used to monitor and track an emitter’s location by observing Doppler frequency shifts of the carrier during short pulsed transmissions. This specific application needs to consider two frequency-stability levels

MOT Loading Enhancement with Stimulated Light Forces

July 31, 2011
Author(s)
Elizabeth A. Donley, Tara C. Liebisch, Eric M. Blanshan, John E. Kitching
We demonstrate atom number enhancement in a magneto-optical trap (MOT) by use of bichromatic cooling to slow an atomic beam that is loaded into a MOT. Bichromatic cooling employs stimulated emission to apply strong cooling forces that are not limited by

Residual PM Noise Evaluation of Radio Frequency Mixers

July 31, 2011
Author(s)
Corey A. Barnes, Archita Hati, Craig W. Nelson, David A. Howe
Direct observation of phase modulated (PM) noise is often difficult due to the high dynamic range that exists between the carrier and the modulated sidebands. A common tool used to reduce the dynamic range is the phase detector, which removes the carrier

Status of a compact cold-atom CPT frequency standard

July 31, 2011
Author(s)
Elizabeth A. Donley, Francois-Xavier R. Esnault, John E. Kitching, Eugene N. Ivanov
We describe the main progress towards the realization of a cold atom frequency standard based on coherent population trapping (CPT). We explain our particular CPT configuration and give details on the experimental setup.

Synchronizing Computer Clocks Using Kalman Filters

July 31, 2011
Author(s)
Judah Levine
I have used the Kalman Filter algorithm to improve the link between the Internet Time Servers operated by the National Institute of Standards and Technology (NIST) and the primary atomic clock ensemble in Boulder, which realizes UTC(NIST) and which is used

Towards an all-digital time scale

July 31, 2011
Author(s)
Stefania Romisch, Steven R. Jefferts, Thomas E. Parker
The implementation of an all-digital time scale is under way at NIST, using a novel 8-channel, all-digital phase measurement system based on subsampling techniques. The phase measurement system is used to compare output signals from several commercial

Update on a Comparison of Cesium Fountain Primary Frequency Standards

July 31, 2011
Author(s)
Thomas E. Parker
An update to a previous long term frequency comparison of cesium fountain primary frequency standards has been made. This update covers the approximate three year interval from March 2008 to March 2011 and also includes two new standards. Also, simulated

Vibration Sensitivity of Optical Components: A Survey

July 31, 2011
Author(s)
Archita Hati, Craig W. Nelson, David A. Howe
We propose and demonstrate a novel technique to measure the vibration sensitivity of two-port fiber-based optical components. It uses a common-arm counter-propagating frequency-shifted interferometer that cancels the vibration induced phase noise of the

Smart Clocks Have a Hand in the Smart Grid

July 29, 2011
Author(s)
Jeffrey Fletcher, Dhananjay Anand, Maruthi Chaluvadi, Julien M. Amelot, Ya-Shian Li-Baboud, James Moyne
Clock synchronization is becoming an increasingly important characteristic of modern wide area monitoring and control systems such as the power grid. It provides an opportunity to coordinate control actions and measurement instants across hundreds of miles

Lithography and Chemical Modeling of Acid Amplfiers for Use in EUV Photoresists

July 28, 2011
Author(s)
Kirstin Kruger, craig higgins, Gregg M. Gallatin, Robert Brainard
We postulate that the best way to simultaneously improve resolution, line edge roughness (LER), and sensitivity all in EUV resists is to increase the number of acid molecules generated per absorbed photon. In previous work, we showed that acid amplifiers

The sixth industrial fluid properties simulation challenge

July 28, 2011
Author(s)
F Case, Anne M. Chaka, Jonathan D. Moore, Raymond D. Mountain, Richard B. Ross, Vincent K. Shen, Eric A. Stahlberg
The sixth industrial fluid properties simulation challenge was held in 2010. The contestants were challenged to predict mutual solubility in liquid-liquid equilibria (LLE) for the PROGLYDE DMM + water system at various temperatures and atmospheric pressure

Initial Reconnaissance of the 2011 Wildland-Urban Interfaces Fires in Amarillo, Texas

July 27, 2011
Author(s)
Alexander Maranghides, William Mell, Karen Ridenour, Derek McNamara
The National Institute of Standards and Technology (NIST) is working to reduce the risk of fire spread in Wildland-Urban Interface (WUI) communities. An objective of this work is to develop first generation tools for improved risk assessment and risk

Single-Photon Sources and Detectors

July 27, 2011
Author(s)
M D. Eisaman, Jingyun Fan, Alan L. Migdall, Sergey Polyakov
We review the current status of single-photon-source and single-photon-detector technologies operating at wavelengths from the ultraviolet to the infrared. We discuss applications of these technologies to quantum communication, a field that is currently
Displaying 24701 - 24725 of 73969
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