You searched on: Author: jon pratt
Displaying records 11 to 20 of 92 records.
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11. 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 ...
12. 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 ...
13. 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 ...
14. 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 ...
15. Report on the first international comparison of small force facilities: A pilot study at the micronewton level
Jon Robert Pratt, Min-Seok Kim, Uwe Brand, Christopher Jones
Measurements of forces less than a micronewton are critical when examining the mechanical behaviors of materials and devices at characteristic length scales below a micrometer. As a result, standards for nanomechanical tests and test equipment are be ...
16. 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 M. 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 ...
17. 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 ...
18. 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 ...
19. An interferometric platform for studying AFM probe deflection
Jon Robert Pratt, Lee Kumanchik, Tony L. Schmitz
This paper describes an interferometric platform for measuring the full-field deflection of atomic force microscope (AFM) probes and generic cantilevers during quasi-static loading. The platform consists of a scanning white light interferometer (SWLI ...
20. Nanomechanical standards based on the intrinsic mechanics of molecules and atoms
Jon Robert Pratt, Gordon Allan Shaw, Douglas T Smith
For more than a decade, instruments based on local probes have allowed us to touch objects at the nanoscale, making it possible for scientists and engineers to probe the electrical, chemical, and physical behaviors of matter at the level of individ ...