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Search Publications

NIST Authors in Bold

Displaying 876 - 900 of 1856

Does Shape Matter? Bioeffects of Gold Nanomaterials in a Human Skin Cell Model

January 13, 2012
Author(s)
Nicole M. Schaeublin, Laura K. Braydich-Stolle, Elizabeth I. Maurer, Kyoungweon Park, Robert I. MacCuspie, A R M N. Afrooz, Navid B. Saleh, R.A. Vaia, Saber Hussain
Gold nanomaterials (AuNMs) have distinctive electronic and optical properties, making them ideal candidates for biological, medical, and defense applications. Therefore, it is imperative to evaluate the potential biological impact of AuNMs before employing

Effect of elastic deformation on frictional properties of few-layer graphene

January 9, 2012
Author(s)
Alexander Y. Smolyanitsky, Jason P. Killgore, Vinod K. Tewary
We describe the results of Brownian dynamics (BD) simulations of an AFM tip scanned on locally suspended few-layer graphene. The effects of surface compliance and sample relaxation are directly related to the observed friction force. We demonstrate that

Spherical indentation testing of poroelastic relaxations in thin hydrogel layers

December 16, 2011
Author(s)
Edwin Chan, Yuhang Hu, Peter M. Johnson, Zhigang Suo, Christopher Stafford
In this work, we present the Poroelastic Relaxation Indentation (PRI) testing approach for quantifying the mechanical and transport properties of thin layers of poly(ethylene glycol) hydrogel materials with thicknesses on the order of 200 m. Specifically

Experimentally Based Methodology for Charge Pumping Bulk Defect Trapping Correction

December 15, 2011
Author(s)
Jason T. Ryan, Richard G. Southwick, Jason P. Campbell, Kin P. Cheung, Chadwin Young, John S. Suehle
We develop a simple experimental approach to remove bulk trap contributions from charge pumping data collected on devices which suffer from large amounts of bulk dielectric electron trapping. The approach is more desirable and easier to implement than

Characterization of Stabilized Zero Valent Iron Nanoparticles

December 10, 2011
Author(s)
Lauren F. Greenlee, Stephanie A. Hooker
The demonstrated toxicity of certain groups of organic micropollutants in water sources has motivated research in developing novel materials that are able to remove dissolved organic molecules from an aqueous system through adsorption and/or degradation

Automated Data Processing and Quantification in Polymer Mass Spectrometry

December 1, 2011
Author(s)
Till Gruendling, Christopher Barner-Kowollik, William E. Wallace, Charles M. Guttman, Anthony J. Kearsley
An overview is given of some new techniques in quantitative composition and molecular mass distribution measurement of synthetic polymers by mass spectrometry. New concepts in data analysis, including peak picking and integration, are also described.

Mechanical Properties of Polymer Nano-Films

November 28, 2011
Author(s)
Junghyun Lee, Jun Y. Chung, Christopher Stafford
Three fundamental mechanical properties of supported glassy polystyrene films with thickness ranging from 250 nm to 9 nm were quantitatively determined by a recently developed wrinkling-cracking method. Films below about 40 nm showed a decrease in both

In situ monitoring of enzyme-catalyzed (co)polymerizations by Raman spectroscopy

November 10, 2011
Author(s)
Matthew T. Hunley, Atul Bhangale, Santanu S. Kundu, Peter M. Johnson, Michael S. Waters, Richard Gross, Kathryn Beers
In situ, fiber optic-based Raman spectroscopy provided real time monitoring of enzyme-catalyzed ring-opening homo- and copolymerizations of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL). A custom designed reactor equipped with in situ fiber optic probe

Reliability Testing of Advanced Interconnect Materials

November 10, 2011
Author(s)
Robert R. Keller, Mark C. Strus, Ann C. Chiaramonti Debay, David T. Read, Younglae Kim, Yung J. Jung
We describe the development of electrical test methods to evaluate damage that determines reliability in advanced, small-scale conductors, including damascene copper and aligned carbon nanotube networks. Rapid thermal cycling induced during high-current AC

Structure and Properties of Polymer Electrolyte Membranes Containing Phosphonic Acids for Anhydrous Fuel Cells

November 9, 2011
Author(s)
Kirt A. Page, Christopher L. Soles, Huagen H. Peng, Do Y. Yoon, Sung-Il Lee, Myeongsoo Song, Kyung-Hwan Yoon, Wolfgang Meyer
Recently, water-free, proton conducting, polymer electrolytes are attracting attention due to their possible application as fuel cell membranes at intermediate temperatures (100 ºC to 200 ºC). Phosphonic acid groups are considered feasible anhydrous proton

Viscoelastic Property Mapping with Contact Resonance Force Microscopy

November 4, 2011
Author(s)
Jason P. Killgore, Donna C. Hurley, Dalia Yablon, Joseph Turner, Philip Yuya, Roger Proksch, Anil Gannepalli, Andy Tsou
We demonstrate accurate nanoscale mapping of loss and storage modulus on a polystyrene-polypropylene blend with contact resonance force microscopy (CR-FM). The viscoelastic properties are extracted from spatially resolved maps of the contact resonance

Influence of chain stiffness on thermal and mechanical properties of polymer thin films

October 25, 2011
Author(s)
Jessica M. Torres, Chengqing C. Wang, E. B. Coughlin, John P. Bishop, Richard A. Register, Robert A. Riggleman, Christopher Stafford, Bryan D. Vogt
The effect of main chain stiffness and side chain flexibility on the elastic modulus and glass transition temperature (Tg) of thin polymer films is investigated using non-traditional polymers formed from 5-(2-phenylethylnorbornene). Depending on the

Determination of Moisture Content of Single-Wall Carbon Nanotubes

October 17, 2011
Author(s)
Rolf L. Zeisler, Rabia Oflaz, Ralph E. Sturgeon, Rick L. Paul, Brian E. Lang, Jeffrey A. Fagan, Joseph W. Lam, Anthony Windust, P Grinberg, Benoit Simard, Christopher T. Kingston
Several techniques were evaluated for the establishment of reliable water/moisture content of single-wall carbon nanotubes. Karl Fischer titration (KF) provides for a direct measure of the water content and was used for benchmarking against results

Radiation-Induced Synthesis of Poly(vinylpyrrolidone) Nanogel

October 14, 2011
Author(s)
Jung-Chul An, Alia Weaver, Byungnam Kim, Aaron Barkatt, Dianne L. Poster, Wyatt N. Vreeland, Joseph Silverman, Mohamad Al-Sheikhly
Studies of the radiation-induced synthesis of poly(vinylpyrrolidone) (PVP) nanogels, intended to provide a basis for obtaining intra-molecular cross-linked products, which are more useful in drug delivery, show that a sharp change in the controlling

Morphological Changes Driven by Nanofibrous Scaffolds Induce Marrow Stromal Cell Osteogenesis

October 11, 2011
Author(s)
Carl G. Simon Jr., Kaushik Chatterjee, Christopher K. Tison, Girish Kumar, Patrick S. Pine, Marc L. Salit, Jennifer H. McDaniel, Marian F. Young
Cells are sensitive to tissue scaffold architecture and these cell-material interactions drive cell functions critical in tissue regeneration. Results presented here demonstrate that nanofiber scaffolds force primary human bone marrow stromal cells (hBMSCs

High Speed Switching Characteristics of Pt/Ta2O5/Cu Memristive Switch

October 8, 2011
Author(s)
Pragya R. Shrestha, Adaku Ochia, Kin P. Cheung, Jason P. Campbell, Helmut Baumgart, Gary Harris
Accurate measurements of the transient details of switching a memristive switch are crucial to the elucidation of the switching mechanism. Such high-speed measurements are often plagued by artifacts. Here we describe a measurement technique capable of

High Frequency Characterization of Contact Resistance and Conductivity of Platinum Nanowires*

October 1, 2011
Author(s)
Kichul Kim, Paul Rice, Thomas M. Wallis, Dazhen Gu, SangHyun S. Lim, Atif A. Imtiaz, Pavel Kabos, Dejan Filipovic
Abstract— Individual platinum (Pt) nanowires (NWs) with 100 nm and 250 nm diameters, embedded in coplanar waveguide (CPW) structures are investigated. Three approaches for characterization of their contact resistance and conductivity at high frequencies

Service Life Prediction for Sealants

September 29, 2011
Author(s)
Christopher C. White, Donald L. Hunston, Kar T. Tan, James J. Filliben
Previous industry consensus postulated that four elements of the weather: Temperature, Humidity, Ultraviolet Radiation, and Mechanical loading were responsible for the majority of the changes observed in sealants exposed to outdoor weathering. The NIST
Displaying 876 - 900 of 1856