You searched on: Author: Jon Pratt
Displaying records 1 to 10 of 83 records.
Resort by: Date / Title
1. A nonlinearity in permanent-magnet systems used in watt balances
Shisong Li, Stephan Schlamminger, Jon Robert Pratt
In watt balances that employ permanent magnet systems to generate the magnetic flux the effects of the weighing current on the magnet systems can generate a systematic bias that can lead to an error in the result if not accounted for. In this article ...
2. High Sensitivity Optomechanical Reference Accelerometer Over 10 kHz
Felipe Guzman, Lee M. Kumanchik, Jon Robert Pratt, Jacob M Taylor
We present an optically detected mechanical accelerometer that achieves a sensitivity of 100 ng/√Hz over a bandwidth of 10 kHz
and is traceable. We have incorporated a Fabry-Perot fiber-optic micro-cavity that is currently capable of measurin ...
3. Determination of the Planck constant using a watt balance with a superconducting magnet system at the
National Institute of Standards and Technology
Stephan Schlamminger, Darine El Haddad, Frank Christian Seifert, Leon S Chao, David B Newell, Richard L Steiner, Jon Robert Pratt
In the past two years measurements were performed with a watt balance at the National Institute of
Standards and Technology (NIST) to determine the Planck constant. A detailed analysis of these
measurements and their uncertainties led to a value ...
4. How to weigh everything from atoms to apples using the revised SI
Jon Robert Pratt
The fact that the unit of mass might soon be derived from the Planck constant, rather than from an artifact standard, can seem daunting and downright baffling when viewed from the vantage point of our day to day perception of mass. After all, at meas ...
5. Functional Constraints and the Design of a New Watt Balance
Leon S Chao, Stephan Schlamminger, Jon Robert Pratt
The functional constraints driving the design of the new permanent-magnet driven watt balance (NIST-4) outline the variables and compromises worthy of addressing. Construction according to these design parameters will demonstrate the high precision c ...
6. Experimental Determination of Mode Correction Factors for Thermal Method Spring Constant Calibration of AFM Cantilevers using Laser Doppler Vibrometry
Richard Swift Gates, William A Osborn, Jon Robert Pratt
Mode corrections factors (MCF‰s) are a significant adjustment to the spring constant values measured using the Thermal cantilever calibration method. Usually, the ideal factor of 0.971 for a tipless rectangular cantilever is used which adjusts the v ...
7. Accurate and Precise Calibration of AFM Cantilever Spring Constants using Laser Doppler Vibrometry
Richard Swift Gates, Jon Robert Pratt
Accurate cantilever spring constants are important in atomic force microscopy in both control of sensitive imaging and to provide correct nanomechanical property measurements. Conventional atomic force microscope (AFM) spring constant calibration t ...
8. Electron Transport in Gold Nanowires: Stable 1-, 2- and 3-Dimensional Atomic Structures
and Non-Integer Conduction States
Francesca M Tavazza, Douglas T Smith, Lyle E Levine, Jon Robert Pratt, Anne Marie Chaka
Experimental conductivity measurements made during highly stable tensile deformation of Au
a rich variety of behaviors, including non-integer quantum conductance plateaus, transitions and
slopes. Using tight binding conductance cal ...
9. Calibration of dynamic sensors for noncontact-atomic force microscopy
Gordon Allan Shaw, Jon Robert Pratt, Zeina Jabbour Kubarych
Access to quantitative information on surface forces in noncontact-atomic force microscopy (NC-AFM) requires the accurate calibration of several key sensor parameters. This work outlines a dynamic method for calibrating the spring constant of tuning ...
10. Atomic Force Microscope Cantilever Flexural Stiffness Calibration: Toward a Standard Traceable Method
Journal of Research (NIST JRES)
Richard Swift Gates, Mark Reitsma, John A Kramar, Jon Robert Pratt
The evolution of the atomic force microscope into a useful tool for measuring mechanical properties of surfaces at the nanoscale has spurred the need for more precise and accurate methods for calibrating the spring constants of test cantilevers. Gro ...