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Search Publications by: Gordon A. Shaw (Fed)

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Displaying 26 - 50 of 55

Calibration of dynamic sensors for noncontact-atomic force microscopy

August 12, 2011
Author(s)
Gordon A. Shaw, Jon R. Pratt, Zeina J. 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 fork

Nanomechanical standards based on the intrinsic mechanics of molecules and atoms

June 7, 2010
Author(s)
Jon R. Pratt, Gordon A. 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 individual

Electrochemical Micromachining of Hastelloy B-2 with Ultrashort Voltage Pulses

September 8, 2009
Author(s)
Gordon A. Shaw, Joseph J. Maurer, Steven E. Fick, Thomas P. Moffat, J. J. Mallett, John L. Hudson
Electrochemical micromachining (ECMM) with ultrashort voltage pulses, a maskless all-electrochemical micro and nanofabrication technique, has been used to fabricate microstructures on a corrosion resistant nickel-based superalloy, Hastelloy B-2. Because of

Accurate Picoscale Forces for Insitu Calibration of AFM

September 3, 2009
Author(s)
Koo-Hyun Chung, Gordon A. Shaw, Jon R. Pratt
The force sensitivity of an atomic force microscope is calibrated directly using an in situ realization of primary electrostatic forces ranging from 320 pN to 3.3 nN with accuracy of a few percent. The absolute accuracy of a common atomic force microscope

Methods for transferring the SI unit of force from millinewtons to piconewtons

June 1, 2009
Author(s)
Gordon A. Shaw, Koo-Hyun Chung, Douglas T. Smith, Jon R. Pratt
The establishment of standards for small force measurement requires a link to an absolute measurement of force traceable to the international system of units (SI). To this end, a host of different means are being employed by the NIST small force

Contactless Differential Conductivity Detection

October 12, 2008
Author(s)
Gordon A. Shaw, David J. Ross, Steven E. Fick, Wyatt N. Vreeland
We propose a new technique, contactless differential conductivity detection (CDCD,) to improve the detection limit of contactless conductivity detection for capillary and microchannel electrophoresis. By exploiting a 3-electrode differential configuration

A New Microdevice for SI-Traceable Forces in Atomic Force Microscopy

June 2, 2008
Author(s)
Gregory W. Vogl, Jason J. Gorman, Gordon A. Shaw, Jon R. Pratt
A new self-excited micro-oscillator is proposed as a velocity standard for dissemination of nanoNewton-level forces that are traceable to the International System of Units (SI). The microfabricated oscillator is top-coated with magnetic thin films and

Reducing Thermal Noise in Molecular Force Spectroscopy

June 2, 2008
Author(s)
Gordon A. Shaw
Molecular force spectroscopy is the practice of testing the mechanical properties of single molecules. The precision determination of these properties requires an instrument capable of piconewton-level force measurement. The atomic force microscope (AFM)

Spring constant calibration of AFM cantilevers with a piezosensor transfer standard

September 24, 2007
Author(s)
Eric Langlois, Gordon A. Shaw, John A. Kramar, Jon R. Pratt, Donna C. Hurley
We describe a method to calibrate the spring constants of cantilevers for atomic force microscopy (AFM). The method makes use of a piezosensor comprised of a piezoresistive cantilever and accompanying electronics. The piezosensor was calibrated before use

Direct Electrostatic Calibration of Hybrid Sensors for Small Force Measurement

June 4, 2007
Author(s)
Koo-Hyun Chung, Gordon A. Shaw, Jon R. Pratt
The measurement of forces from piconewtons to millinewtons is an area of interest from both an applied and pure research standpoint, however creating a link between small forces and the International System of Units (SI) has been difficult. In this work, a

Traceable Micro-Force Sensor for Instrumented Indentation Calibration

April 10, 2007
Author(s)
Douglas T. Smith, Gordon A. Shaw, R M. Seugling, D Xiang, Jon R. Pratt
Instrumented indentation testing (IIT), commonly referred to as nanoindentation when small forces are used, is a popular technique for determining the mechanical properties of small volumes of material. Sample preparation is relatively easy, usually

A Piezoresistive Cantilever Force Sensor for Direct AFM Force Calibration

April 8, 2007
Author(s)
Jon R. Pratt, John A. Kramar, Gordon A. Shaw, Douglas T. Smith, John M. Moreland
We describe the design, fabrication, and calibration testing of a new piezoresistive cantilever force sensor suitable for the force calibration of atomic force microscopes in a range between tens of nanonewtons to hundreds of micronewtons. The sensor is

The Stiffness of Collagen Fibrils Influences Vascular Smooth Muscle Cell Phenotype

March 1, 2007
Author(s)
Dennis P. McDaniel, Gordon A. Shaw, John T. Elliott, Kiran Bhadriraju, Curtis W. Meuse, Koo-Hyun Chung, Anne L. Plant
Cells receive signals from the extracellular matrix through receptor-dependent interactions, but they are also influenced by the mechanical properties of the matrix. While bulk properties of substrates have been shown to effect cell behavior, we show here

Traceable Micro-Force Calibration for Instrumented Indentation Testing

February 13, 2007
Author(s)
Douglas T. Smith, Gordon A. Shaw, Richard Seugling, Jon R. Pratt, Dan Xiang
We describe the development, performance and application of an accurate SI-traceable force calibration and verification system for potential use in the field calibration of commercial instrumented indentation testing (IIT) instruments. The system consists

Force Calibration Via Electrostatics

January 1, 2006
Author(s)
Jon R. Pratt, John A. Kramar, Gordon A. Shaw, Lee Kumanchik
We describe the electrical and length measurements necessary to realize micronewton forces in a fashion consistent with the International System of Units (SI). We first discuss instrumentation and procedures required to accurately characterize an

New Reference Standards and Artifacts for Nanoscale Physical Property Characterization

January 1, 2006
Author(s)
Jon R. Pratt, John A. Kramar, Gordon A. Shaw, Richard S. Gates, Paul Rice, John M. Moreland
This paper provides an overview of calibration artifacts being developed at the National Institute of Standards and Technology (NIST) that are intended to aid the accurate determination of nanoscale physical properties across a broad range of applications