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Displaying 26 - 50 of 98

Assessing Electron Backscattered Diffraction and Confocal Raman Microscopy Strain Mapping Using Wedge-indented Si

February 17, 2016
Author(s)
Lawrence Henry Friedman, Mark D. Vaudin, Stephan J. Stranick, Gheorghe Stan, Yvonne B. Gerbig, William Alexander Osborn, Robert F. Cook
The accuracy of electron backscattered diffraction (EBSD) and confocal Raman microscopy (CRM) for small-scale strain mapping are assessed using the multi-axial strain field surrounding a wedge indentation in Si as a test vehicle. The strain field is

Multi-Scale Effects in the Strength of Ceramics

October 15, 2015
Author(s)
Robert F. Cook
Multiple length-scale effects are demonstrated in indentation-strength measurements of a range of ceramic materials under inert and reactive conditions. Meso-scale effects associated with flaw disruption by lateral cracking at large indentation loads are

THE COMPELLING CASE FOR INDENTATION AS A FUNCTIONAL EXPLORATORY AND CHARACTERIZATION TOOL

September 15, 2015
Author(s)
Robert F. Cook, David B. Marshall, Nitin P. Padture, Michelle L. Oyen, Antonia Pajares, Jodie E. Bradby, Ivar E. Reimanis, Rajan Tandon, Trevor F. Page, George M. Pharr, Brian R. Lawn
The utility of indentation testing for characterizing a wide range of mechanical properties of brittle materials is highlighted in light of recent articles questioning its validity, specifically in relation to the measurement of toughness. Contrary to

Heterogeneity and length scale effects in PEG-based hydrogels

August 10, 2015
Author(s)
Brian G. Bush, Jenna M. Shapiro, Frank W. DelRio, Robert F. Cook, Michelle L. Oyen
Colloidal-probe spherical indentation load-relaxation experiments are conducted on poly(ethylene glycol) (PEG) hydrogel materials to quantify the steady-state mechanical properties and time-dependent transport properties in a single experiment. A probe

Fracture strength of micro- and nano-scale silicon components

May 13, 2015
Author(s)
Frank W. DelRio, Robert F. Cook, Brad Boyce
Silicon devices are ubiquitous in many micro- and nano-scale technological applications, most notably microelectronics and microelectromechanical systems (MEMS). Despite their widespread usage, however, issues related to uncertain mechanical reliability

Preparation of silver nanoparticle loaded cotton threads to facilitate measurement development for textile applications

January 26, 2015
Author(s)
Justin M. Gorham, Karen E. Murphy, Jingyu Liu, Dimitri Tselenchuk, Gheorghe NMN Stan, Thao M. Nguyen, Richard D. Holbrook, Michael R. Winchester, Robert F. Cook, Robert MacCuspie, Vincent A. Hackley
FOREWORD This NIST special publication (SP) is one in a series of NIST SPs that address research needs articulated in the National Nanotechnology Initiative (NNI) Environmental, Health, and Safety Research Strategy published in 2011 [1]. This Strategy

Designing a standard for strain mapping: HR-EBSD analysis of SiGe thin film structures on Si

January 1, 2015
Author(s)
Mark D. Vaudin, William A. Osborn, Lawrence H. Friedman, Justin M. Gorham, Robert F. Cook, Victor Vartanian
Patterned SiGe thin film structures, heteroepitaxially deposited on Si substrates, are investigated as potential reference standards to establish the accuracy of high resolution electron backscattered diffraction (HR-EBSD) strain measurement methods. The

Stress mapping of micromachined polycrystalline silicon devices via confocal Raman microscopy

June 15, 2014
Author(s)
Grant A. Myers, Siddharth Hazra, Maarten de Boer, Chris A. Michaels, Stephan J. Stranick, Ryan P. Koseski, Robert F. Cook, Frank W. DelRio
Stress mapping of micromachined polycrystalline silicon devices with components in various levels of uniaxial tension was performed. Confocal Raman microscopy was used to form two-dimensional maps of Raman spectral shifts, which exhibited variations on the

Accurate Spring Constant Calibration for very Stiff Atomic Force Microscopy Cantilevers

November 26, 2013
Author(s)
Scott Grutzik, Richard S. Gates, Yvonne B. Gerbig, Douglas T. Smith, Robert F. Cook, Alan Zehnder
There are many atomic force microscopy (AFM) applications that rely on quantifying the force between the AFM cantilever tip and the sample. The AFM does not explicitly measure force, however, so in such cases knowledge of the cantilever stiffness is

Frictional properties of native and functionalized type I collagen thin films

October 2, 2013
Author(s)
Koo-hyun Chung, Antony Chen, Christopher Anderton, Kiran Bhadriraju, Anne L. Plant, Brian G. Bush, Robert F. Cook, Frank W. DelRio
Frictional properties of native and fibronectin (FN)-functionalized type I collagen (COL) thin films were studied via atomic force microscopy. The COL lateral contact stiffness was dependent only on the hydration state, indicating that shear deformation

Development of a Precision Nanoindentation Platform

July 18, 2013
Author(s)
Douglas T. Smith, Bartosz K. Nowakowski, Robert F. Cook, Stuart T. Smith, Luis F. Correa
This paper presents the design, construction and performance of a surface- referenced nanoindentation instrument termed a precision nanoindentation platform (PNP). The PNP is a symmetrically designed instrument with a centrally located indenter tip

On the bending strength of single-crystal silicon theta-like specimens

July 10, 2013
Author(s)
Rebecca R. Kirkpatrick, William Alexander Osborn, Michael S. Gaither, Richard S. Gates, Frank W. DelRio, Robert F. Cook
A new theta geometry was developed for micro-scale bending strength measurements. The new "gap" theta specimen was a simple modification of the arch theta specimen that enabled micro-scale tensile testing. The gap theta was demonstrated here on single

Interfacial Mechanical Properties of n-Alkylsilane Monolayers on Silicon Substrates

February 1, 2013
Author(s)
Brian G. Bush, Frank W. DelRio, Cherno Jaye, Daniel A. Fischer, Robert F. Cook
The interfacial properties of n-alkylsilane self-assembled monolayers on silicon were investigated by normal force spectroscopy and lateral force measurements and correlated with molecular structure via near-edge X-ray absorption fine structure (NEXAFS)

Indentation device for in situ Raman spectroscopic and optical studies

December 12, 2012
Author(s)
Yvonne B. Gerbig, Chris A. Michaels, Aaron M. Forster, John W. Hettenhouser, Walter E. Byrd, Dylan J. Morris, Robert F. Cook
Instrumented indentation is a widely used technique to study the mechanical behavior of materials at small length scales and thus has been exploited in particular for metals, ceramics, glasses, and polymers. Mechanical tests of bulk materials, microscopic

High Confidence Level Calibration for AFM Based Fracture Testing of Nanobeams

June 11, 2012
Author(s)
Scott Grutzik, Richard S. Gates, Yvonne B. Gerbig, Robert F. Cook, Melissa Hines, Alan Zehnder
When designing micro- or nanoelectromechanical systems, (MEMS and NEMS), it is important to consider whether structural elements will withstand loads experienced during operation. Fracture behavior at length scales present in MEMS and NEMS is much di erent