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Search Publications by: John A. Kramar (Fed)

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Displaying 1 - 25 of 134

Measurement of 100 nm Monodisperse Particles by Four Accurate Methods: Uncertainty and Traceability

February 12, 2024
Author(s)
George Mulholland, Kaleb Duelge, Vincent A. Hackley, Natalia Farkas, John A. Kramar, Keiji Takahata, Michael Zachariah, Hiromu Sakurai, Kensei Ehara
Accurate measurements of particle diameter are necessary for quantitative characterization of key aerosol properties including the Cunningham slip correction, charging probability, the diffusion coefficient, the coagulation coefficient, and optical

Dynamic light scattering distributions by any means

May 21, 2021
Author(s)
Natalia Farkas, John A. Kramar
Dynamic light scattering (DLS) is an essential technique for nanoparticle size analysis and has been employed extensively for decades, but despite its long history and popularity, the choice of weighting and mean of the size distribution often appears to

Comparison of electrostatic and photon pressure force references at the nanonewton level

May 3, 2021
Author(s)
Gordon Shaw, John A. Kramar, Paul Williams, Matthew Spidell, Richard Mirin, Julian Stirling
This work describes a comparison between nanonewton force references derived from an electrostatic force balance and photon pressure force from calibrated laser optical power in the 1 watt range. The NIST Electrostatic Force Balance (EFB) is used to

Interlaboratory comparison of nanoparticle size measurements between NMIJ and NIST using two different types of dynamic light scattering instruments

August 6, 2019
Author(s)
Kayori Takahashi, John A. Kramar, Natalia Farkas, Keiji Takahata, Ichiko Misumi, Kentaro Sugawara, Satoshi Gonda, Kensei Ehara
The question of how to relate particle sizes measured using a fixed-angle dynamic light scattering (DLS) instrument with those measured using a multi-angle DLS instrument is addressed. A series of nearly monodisperse polystyrene latex (PSL) particles with

Milligram mass metrology using an electrostatic force balance

September 28, 2016
Author(s)
Gordon A. Shaw, Julian Stirling, John A. Kramar, Alexander D. Moses, Patrick J. Abbott, Richard L. Steiner, Andrew D. Koffman, Jon R. Pratt, Zeina J. Kubarych
Although mass is typically defined within the International System of Units (SI) at the Kilogram level, the pending redefinition of the SI provides an opportunity to realize mass at any scale using electrical metrology. We propose the use of an

Nanometer level sampling and control of a scanning electron microscope

June 2, 2015
Author(s)
Bradley N. Damazo, Andras Vladar, Olivier M. Marie-Rose, John A. Kramar
The National Institute of Standards and Technology (NIST) is developing a specialized, metrology scanning electron microscope (SEM), having a metrology sample stage measured by a 38 picometer resolution, high-bandwidth laser interferometer system. The

Milligram Mass Metrology Using Electrostatics

August 25, 2014
Author(s)
Gordon A. Shaw, John A. Kramar
— Although mass has historically been defined using an artifact standard, other means of realization are possible. One alternative approach employs a precision electromechanical balance, using the SI electrical units to derive a force used to measure the

Reference Materials 8096 and 8097 - The MEMS 5-in-1 RMs: Homogeneous and Stable

May 14, 2014
Author(s)
Janet M. Cassard, Jon C. Geist, John A. Kramar
The NIST Microelectromechanical Systems (MEMS) 5-in-1 Reference Materials (RMs) were developed to assist users in validating their use of five documentary standard test methods. A Reference Material can be defined as a material whose property values are

Kinematic Modeling and Calibration of a Flexure Based Hexapod Nanopositioner

August 21, 2012
Author(s)
Hongliang Shi, Hai-Jun Su, Nicholas Dagalakis, John A. Kramar
This paper covers the kinematic modeling of a flexure-based, hexapod nanopositioner and a new method of calibration for this type of nanopositioner. This six degrees of freedom tri-stage nanopositioner can generate small displacement, high-resolution