U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications

NIST Authors in Bold

Displaying 626 - 650 of 2606

Reference Module in Materials Science and Materials Engineering MATS 01908

February 1, 2016
Author(s)
Randolph E. Elmquist, Anthony Hartland
The cryogenic current comparator is used to maintain national representations of the ohm based on the quantized Hall resistance standard. The measurement technique utilizes the Meissner effect to establish accurate resistance ratios with specialized

Recent approaches for bridging the pressure gap in photoelectron microspectroscopy

January 29, 2016
Author(s)
Andrei A. Kolmakov, Luca Gregoratti, Maya Kiskinova, Sebastian Gunther
Ambient pressure photoelectron spectroscopy (APPES) and microscopy are at the frontier of modern chemical analysis at liquid-gas, solid-liquid and solid-gas interfaces, bridging science and engineering of functional materials. Complementing the current

Lateral Tip Control Effects in CD-AFM Metrology: The Large Tip Limit

January 25, 2016
Author(s)
Ronald G. Dixson, Ndubuisi G. Orji, Ryan Goldband
Sidewall sensing in CD-AFMs usually involves continuous lateral dithering of the tip or the use of a control algorithm and fast response piezo actuator to position the tip in a manner that resembles touch-triggering of coordinate measuring machine (CMM)

Experimental demonstration of deep frequency modulation interferometry

January 21, 2016
Author(s)
Katharina-Sofie Isleif, Oliver Gerberding, Thomas Schwarze, Moritz Mehmet, Gerhard Heinzel, Felipe Guzman
Experiments for space and ground-based gravitational wave detectors often require large dynamic range interferometric position readout of test masses with 1 pm/√Hz precision over long time scales. Heterodyne interferometer schemes that achieve such

A Rational Foundation for Software Metrology

January 20, 2016
Author(s)
David W. Flater, Paul E. Black, Elizabeth N. Fong, Raghu N. Kacker, Vadim Okun, Stephen S. Wood, David R. Kuhn
Much software research and practice involves ostensible measurements of software, yet little progress has been made on an SI-like metrological foundation for those measurements since the work of Gray, Hogan, et al. in 1996-2001. Given a physical object

Measurement Challenges and Metrology for Monitoring CO2 Emissions from Smokestacks – Workshop Summary

January 20, 2016
Author(s)
Aaron N. Johnson, Rodney A. Bryant, Tamae M. Wong, James R. Whetstone, Eric Harman, Woong Kang, Keith A. Gillis, Hsin-Hung Lee, Iosif I. Shinder, Liang Zhang
On April 20-21, 2015, NIST hosted a workshop that, through measurement science, enabled the owners of stationary sources (primarily the electric power industry) and their regulatory agencies (federal and state) to better characterize greenhouse gas (GHG)

Fe-catalyzed etching of exfoliated graphite through carbon hydrogenation

January 8, 2016
Author(s)
Guangjun Cheng, Christina A. Hacker, Curt A. Richter, Angela R. Hight Walker
We present an investigation on the etching of graphite catalyzed by the particles produced by dewetting Fe thin films on graphite in forming gas. Raman mapping of the etched graphite shows the thickness variation in the etched channels and reveals that the

Benchmarking Robot Force Control Capabilities: Experimental Results

January 7, 2016
Author(s)
Joseph A. Falco, Jeremy A. Marvel, Richard J. Norcross, Karl Van Wyk
Metrics and test methods are needed to characterize the control capabilities of robots with both intrinsic and extrinsic force sensing. The availability of these benchmarks will motivate research product development, and provide a mechanism for reporting

Advances in Thermometry

January 1, 2016
Author(s)
Michael R. Moldover, Weston L. Tew, Howard W. Yoon
The last 25 years have seen tremendous progress in thermometry in the moderate temperature range (1 K to 1235 K). Various primary thermometers — based on different physics —have uncovered errors in the International Temperature Scale of 1990 and set the

Density measurements of compressed-liquid dimethyl ether + pentane mixtures

January 1, 2016
Author(s)
Stephanie L. Outcalt, Eric W. Lemmon
Compressed-liquid densities of three compositions of the binary mixture dimethyl ether (CAS No. 115-10-6) + pentane (CAS No. 109-66-0) have been measured with a vibrating U-tube densimeter. Measurements were made at temperatures from 270 K to 390 K with

Design of a breast phantom for quantitative MRI

January 1, 2016
Author(s)
Kathryn E. Keenan, Sheye O. Aliu, Lisa J. Wilmes, David C. Newitt, Ella F. Jones, Wen Li, Michael A. Boss, Nola M. Hylton
Purpose: We present a breast phantom designed to enable quantitative assessment of measurements of T 1 relaxation time, apparent diffusion coefficient (ADC), and other attributes of breast tissue, with long-term support from a national metrology institute

Tip characterization method using multi-feature characterizer for CD-AFM

December 23, 2015
Author(s)
Ndubuisi G. Orji, Hiroshi Itoh, Chumei Wang, Ronald G. Dixson, Sebastian Schmidt, Bernd Irmer, Peter S. Walecki
In atomic force microscopy (AFM) metrology, the tip is a key source of uncertainty. Images taken with an AFM show a change in feature width and shape that depends on tip geometry. This geometric distortion is more pronounced when measuring features with

Methods and Tools for Performance Assurance of Smart Manufacturing Systems

December 22, 2015
Author(s)
Deogratias Kibira, Katherine C. Morris, Senthilkumaran Kumaraguru
The emerging concept of smart manufacturing systems is defined in part by the introduction of new technologies that are promoting rapid and widespread information flow within the manufacturing system and surrounding its control. These systems can deliver

Hopper Scales - Selecting the Appropriate Device

December 15, 2015
Author(s)
John W. Barton
The NIST Office of Weights and Measures (OWM) over time have received a number of inquiries regarding the suitability, use, and testing of hopper-type scales. The nature of those inquiries provides some indication that there is a lack of detailed

Metrological challenges for measurements of key climatological observables: Oceanic salinity and pH, and atmospheric humidity. Part 1: overview

December 15, 2015
Author(s)
Rainer Feistel, Robert Wielgosz, Stephanie A. Bell, M F. Camoes, J R. Cooper, P Dexter, A G. Dickson, P Fisicaro, Allan H. Harvey, M Heinonen, Olaf Hellmuth, H J. Kretzschmar, J W. Lovell-Smith, Trevor J. McDougall, R Pawlowicz, S Seitz, Petra Spitzer, D Stoica, H Wolf, P Ridout
Water in its three ambient phases plays the dominant thermodynamic role for the functioning principles of the terrestrial climate system. Together with clouds, water vapour in the atmosphere is the strongest greenhouse gas (followed by clouds and carbon

Potential Stable Low-Permeation Rate Standard Based on Micro-machined Silicon

December 15, 2015
Author(s)
Grady S. White, Adrian Verwolf, Chris M. Poling, Nicholas Barbosa, Nikki S. Rentz
Silicon wafers with micro-machined holes were evaluated for use as low permeation standard artifacts. Accuracy, stability, and reliability were assessed. Two experimental techniques were used: chilled mirror hygrometer and mass loss. The wafers exhibited a

Broadband Optical Properties of Graphene by Spectroscopic Ellipsometry

December 11, 2015
Author(s)
Wei Li, Nhan Van Nguyen, Guangjun Cheng, Angela R. Hight Walker, David J. Gundlach, Yiran Liang, boyuan Tian, Xuelei Liang, Lian-Mao Peng
The broadband (0.7 eV to 9.0 eV) optical properties of chemical-vapor-deposition (CVD) grown graphene are determined by spectroscopic ellipsometry. The optical absorption follows the fine structure constant in the energy range from 1.0 eV to 2.0 eV, but
Displaying 626 - 650 of 2606