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Metrology

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Displaying 451 - 475 of 2728

Spatial Dimensions in Atomic Force Microscopy: Instruments, Effects, and Measurements

August 15, 2018
Author(s)
Ronald G. Dixson, Ndubuisi G. Orji, Ichiko Misumi, Gaoliang Dai
Atomic force microscopes (AFMs) are commonly and broadly regarded as being capable of three dimensional imaging. However, conventional AFMs suffer from both significant functional constraints and imaging artifacts that render them less than fully three

Waveform metrology: Signal measurements in a modulated world

August 3, 2018
Author(s)
Paul D. Hale, Dylan F. Williams, Andrew M. Dienstfrey
In this work, we review the \full waveform metrology" concept that we introduced at the National Institute of Standards and Technology. Under this paradigm the full waveform and its functional representation is the target measurand. From the waveform

A Highly Linear Calibration Metric for TES X-ray Microcalorimeters

August 2, 2018
Author(s)
Christine G. Pappas, Joseph W. Fowler, Douglas A. Bennett, William B. Doriese, Young I. Joe, Kelsey M. Morgan, Galen C. O'Neil, Joel N. Ullom, Daniel S. Swetz
Transition-edge sensor X-ray microcalorimeters are usually calibrated empirically, as the most widely-used calibration metric, optimal filtered pulse height (OFPH), in general has an unknown dependance on photon energy, E γ. Because the calibration

A new realization of SI for organic chemical measurement: NIST PS1 Primary Standard for quantitative NMR (Benzoic Acid)

July 30, 2018
Author(s)
Michael A. Nelson, Jason F. Waters, Blaza Toman, Brian E. Lang, Alexander R?ck, Kathrin Breitruck, Markus Obkircher, Anthony Windust, Katrice A. Lippa
Metrological traceability to common references supports the comparability of chemical measurement results produced by different analysts, at various times, and at separate places. Ideally, these references are realizations of base units of the

NIST Micronutrients Measurement Quality Assurance Program: Spring and Fall 1986 Comparability Studies Results for Round Robins VII and VIII Fat Soluble Vitamins and Carotenoids in Human Serum

July 27, 2018
Author(s)
Jeanice M. Brown Thomas, David L. Duewer, Margaret C. Kline, Neal Craft, Fillmer Ruegg, Emil Schonberger, Robert Schaffer, Robert Paule
From 1984 to 2017, the National Institute of Standards and Technology coordinated the Micronutrients Measurement Quality Assurance Program (MMQAP) for laboratories that measure fat soluble vitamins and carotenoids in human serum and plasma. This report

A reference high-pressure CO2 adsorption isotherm for ammonium ZSM-5 zeolite: results of an interlaboratory study

July 26, 2018
Author(s)
Huong Giang T. Nguyen, Laura Espinal, Roger D. van Zee, Matthias Thommes, Blaza Toman, Sterlin Hudson, Enzo Mangano, Stefano Brandani, Katie Cychosz, Pieter Bertier, Feng Yang, Bernhard Krooss, Rebecca Siegelman, Jeffrey Long, Yoko Nakada, Kazu Nakai, Armin Ebner, James Ritter, Aaron Moran, Orhan Talu, Yi Huang, Krista Walton, Pierre Billemont, Guy de Weireld
This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM

Imaging Through Fire Using Narrow-Spectrum Illumination

July 23, 2018
Author(s)
Christopher M. Smith, Matthew Hoehler
This paper demonstrates a simple method to enhance visibility through clean-burning flames that allows new opportunities to perform optical metrology in fire research. The method combines narrow-spectrum, blue illumination and matched optical filters to

A radial calibration window for analytical ultracentrifugation

July 20, 2018
Author(s)
Thomas W. LeBrun, Peter Schuck, Wei Ren, Justine Yoon, Xianghui Dong, Nicole Y. Morgan, Jeffrey Fagan, Huaying Zhao
Analytical ultracentrifugation (AUC) is a first-principles based method for studying particles in solution by monitoring the evolution of their radial concentration distribution as a function of time in the presence of a high centrifugal field. In

Epitaxial Graphene for High-Current QHE Resistance Standards

July 9, 2018
Author(s)
Mattias Kruskopf, Jiuning Hu, Bi Y. Wu, Yanfei Yang, Hsin Y. Lee, Albert F. Rigosi, David B. Newell, Randolph E. Elmquist
We report the growth of large-area monolayer graphene on the centimeter scale using an optimized growth process allowing for reproducibility and morphology improvements. Magneto-transport measurements on graphene quantum Hall effect devices demonstrate the

Epitaxial Graphene p-n Junctions

July 9, 2018
Author(s)
Jiuning Hu, Mattias Kruskopf, Yanfei Yang, Bi Y. Wu, Jifa Tian, Alireza R. Panna, Albert F. Rigosi, Hsin Y. Lee, George R. Jones Jr., Marlin E. Kraft, Dean G. Jarrett, Kenji Watanabe, Takashi Taniguchi, Randolph E. Elmquist, David B. Newell
We report the fabrication and measurement of top gated epitaxial graphene p-n junctions where exfoliated hexgonal boron nitride (hBN) is used as the gate dielectric. The four terminal longitudinal resistance across a single junction is well quantized at R_

DC Comparison of a Programmable Josephson Voltage Standard and a Josephson Arbitrary Waveform Synthesizer

July 7, 2018
Author(s)
Alain Rufenacht, Nathan Flowers-Jacobs, Anna Fox, Steven B. Waltman, Robert E. Schwall, Paul Dresselhaus, Samuel P. Benz, Charles J. Burroughs
We present the first dc comparison of a programmable Josephson voltage standards and a pulse- driven Josephson arbitrary waveform synthesizer (JAWS) at 3 V. Both devices are mounted side- by-side on the cold stage of a cryocooler. The relative agreement

Measuring the Leakage Current to Ground in Programmable Josephson Voltage Standards

July 7, 2018
Author(s)
Alain Rufenacht, Charles J. Burroughs, Paul Dresselhaus, Samuel P. Benz
The voltage error associated with the leakage current of programmable Josephson voltage standards (PJVS) is one of the largest contributions to the uncertainty in direct comparison of voltage standards. Due to the parallel biasing scheme of the PJVS and

Three Volt Pulse-Driven Josephson Arbitrary Waveform Synthesizer

July 7, 2018
Author(s)
Nathan Flowers-Jacobs, Alain Rufenacht, Anna Fox, Steven B. Waltman, Justus Brevik, Paul Dresselhaus, Samuel P. Benz
This paper describes a new generation of Josephson Arbitrary Waveform Synthesizers which generate ac waveforms with a root-mean-squared (rms) amplitude of 3 V over a quantum-accurate operating range greater than 1 mA at 1 kHz. This system is composed of

Automated Direct Comparison of Two Cryocooled 10 Volt Programmable Josephson Voltage Standards

July 6, 2018
Author(s)
Alain Rufenacht, Yi-hua D. Tang, Stephane Solve, Anna E. Fox, Paul D. Dresselhaus, Charles J. Burroughs, Robert E. Schwall, Regis Chayramy, Samuel P. Benz
We have performed direct dc comparisons between two cryocooled 10 V programmable Josephson voltage standards utilizing an automated synchronization scheme for the voltage reversals, which enables the use of a high-sensitivity analog null detector on its 10

Walk-through Metal Detector Testing and the Need to Emulate Natural Body Motion

July 5, 2018
Author(s)
Nicholas G. Paulter Jr., Donald R. Larson, Nicklaus F. Troje
The effect of motion through the portal of a walk-through metal detector (WTMD) has often been considered to contribute to the uncertainty in detecting threat objects being carried through the WTMD. However, typical metrological testing uses a robotic
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