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Search Publications by

Wei Ren (Fed)

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Displaying 1 - 15 of 15

Physical Models and Dimensional Traceability of WR15 Rectangular Waveguide Standards for Determining Systematic Uncertainties of Calibrated Scattering-Parameters

August 10, 2020
Jeffrey A. Jargon, Dylan F. Williams, Angela C. Stelson, Christian J. Long, Aaron M. Hagerstrom, Paul D. Hale, John R. Stoup, Eric S. Stanfield, Wei Ren
In this report, we document the models and dimensional traceability of our WR15 rectangular waveguide standards for performing multiline thru-reflect-line calibrations from 50 GHz to 75 GHz using vector network analyzers. We identify the equations used in

X-ray computed tomography instrument performance evaluation: Detecting geometry errors using a calibrated artifact

April 30, 2019
Balasubramanian Muralikrishnan, Katharine M. Shilling, Steven D. Phillips, Wei Ren, Vincent D. Lee, Felix H. Kim, Gabriel Alberts, Valentina Aloisi
X-ray computed tomography (XCT) is uniquely suitable for non-destructive dimensional metrology of delicate or internal features generated from the additive manufacturing process. While XCT has long been used in medical imaging, it has only been used for

A radial calibration window for analytical ultracentrifugation

July 20, 2018
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

Towards the Development of a Documentary Standard for Derived-Point to Derived-Point Distance Performance Evaluation of Spherical Coordinate 3D Imaging Systems

October 30, 2015
Balasubramanian Muralikrishnan, Katharine M. Shilling, Prem K. Rachakonda, Wei Ren, Vincent D. Lee, Daniel S. Sawyer
This paper describes ongoing research work within the Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) in support of the development of a documentary standard for derived-point to derived-point distance

Applications of Profile Filtering in the Dimensional Metrology of Fuel Cell Plates

May 14, 2013
Balasubramanian Muralikrishnan, Wei Ren, Eric S. Stanfield, Dennis S. Everett, Xiaoyu A. Zheng, Theodore D. Doiron
We describe the application of several surface profile filters as an enabling tool in the dimensional measurements of an engineering artifact, namely, a fuel cell plate. We recently reported work on the development of a non-contact system for dimensional

High Accuracy Measurements Using a Scanning System with a Single Point Triangulation Sensor

May 13, 2013
Theodore D. Doiron, Wei Ren, Eric S. Stanfield, Balasubramanian Muralikrishnan, Christopher J. Blackburn
The capabilities of non-contact laser spot triangulation sensors for high accuracy measurements have slowly increased over the past decade, and now have usable resolution below 0.1 µm. The Dimensional Metrology Group has developed a simple scanning system

Assessing Ranging Errors as a Function of Azimuth in Laser Trackers and Tracers

April 18, 2013
Balasubramanian Muralikrishnan, Vincent D. Lee, Christopher J. Blackburn, Daniel S. Sawyer, Steven D. Phillips, Wei Ren, Ben Hughes
Tilt and radial error motion of a laser tracker head as it spins about the two axes results in small but measurable ranging and angle errors. The laser tracer, on the other hand, measures range with respect to the center of a high quality stationary sphere

Performance Evaluation Experiments on a Laser Spot Triangulation Probe

November 25, 2011
Balasubramanian Muralikrishnan, Wei Ren, Dennis S. Everett, Eric S. Stanfield, Theodore D. Doiron
Laser triangulation probes are increasingly used for dimensional measurements in a variety of applications. At the National Institute of Standards and Technology, we have recently explored the use of laser spot triangulation probes to determine dimensional


November 15, 2011
Balasubramanian Muralikrishnan, Wei Ren, Dennis S. Everett, Eric S. Stanfield, Theodore D. Doiron
Non-contact dimensional measurement of fuel cell plates is critical to the eventual rapid manufacture by supporting in-process measurement and control. This need has been identified by the Department of Energy’s Hydrogen Program, and by numerous

Dimensional Metrology of Bipolar Fuel Cell Plates Using Laser Spot Triangulation Probes

March 22, 2011
Balasubramanian Muralikrishnan, Wei Ren, Dennis S. Everett, Eric S. Stanfield, Theodore D. Doiron
As in any engineering component, manufacturing a bipolar fuel cell plate for a polymer electrolyte membrane (PEM) hydrogen fuel cell power stack to within its stated design tolerances is critical in achieving the intended function. In a bipolar fuel cell