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Nanotechnology

Nanometrology

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Displaying 526 - 550 of 866

Nanoscale Reference Materials for Environmental, Health, and Safety Measurements: Needs, Gaps, and Opportunities

November 7, 2012
Author(s)
Aleksandr B. Stefaniak, Vincent A. Hackley, Gert Roebben, Kensei Ehara, Steve Hankin, Michael T. Postek, Iseult Lynch, Wei-En Fu, Thomas P. Linsinger, Andreas Th?nemann
There is a need to understand and manage potential risks posed to workers, the public, and the environment from exposure to engineered nanomaterials. In response, several organizations have developed lists of relevant nano-objects and of physico-chemical

Quantifying Dithiothreitol Displacement of Functional Ligands from Gold Nanoparticles

October 27, 2012
Author(s)
De-Hao D. Tsai, Frank W. DelRio, Sherrie R. Elzey, Suvajyoti S. Guha, Michael R. Zachariah, Vincent A. Hackley, Melanie P. Shelton
Dithiothreitol (DTT)-based displacement is widely utilized for separating ligands from their gold nanoparticle (AuNP) conjugates, a critical step for differentiating and quantifying surface-bound functional ligands and therefore the effective surface

Temperature-dependent mechanical-resonance frequencies and damping in ensembles of gallium nitride nanowires

October 22, 2012
Author(s)
Kristine A. Bertness, Norman A. Sanford, J. R. Montague, H.S. Park, Victor M. Bright, Charles T. Rogers
We have measured singly clamped cantilever mechanical-resonances in ensembles of as-grown gallium nitridenanowires (GaN NWs), from 12 K to 320 K. Resonance frequencies are approximately linearly dependent on temperature near 300 K with relative shifts of

Aggregation/agglomeration state of carbon nanotubes

October 12, 2012
Author(s)
Vivek M. Prabhu, Toshiya Okazaki, Takeshi Eitoku, Masayoshi Tange, Haruhisa Kato
Evaluation of aggregation and agglomeration of carbon nanotube (CNT) solution has been one of the key issues for applications. Here we introduce a simple method based on depolarized dynamic light scattering (DDLS) performed at multiple scattering angles to

High-Resolution Local Current Measurement of CdTe Solar Cells

October 4, 2012
Author(s)
Heayoung Yoon, Dmitry A. Ruzmetov, Paul M. Haney, Marina S. Leite, Behrang H. Hamadani, Albert A. Talin, Nikolai B. Zhitenev
We investigate local electronic properties of CdTe solar cells using electron beam to excite electron-hole pairs and evaluate spatially resolved photocurrent characteristics. Standard semiconductor processes were used to fabricate Ohmic metal contacts on

Toward a Probe-Based Method for Determining Exfoliation Energies of Lamellar Materials

October 4, 2012
Author(s)
Zhao Z. Deng, Alexander Smolyanitsky, Qunyang Li, Xi-Qiao Feng, Rachel J. Cannara
We discuss a potential new measurement application based on nanotribological measurements and simulations of the model lamellar material graphite. While frictional forces always oppose motion, we have observed that friction increases with decreasing load

MEMS Kinematics by Super-Resolution Fluorescence Microscopy

September 27, 2012
Author(s)
Craig D. McGray, Samuel M. Stavis, Joshua Giltinan, Eric Eastman, Samara L. Firebaugh, Jenelle Piepmeier, Jon C. Geist, Michael Gaitan
Super-resolution fluorescence microscopy is used for the first time to study the nanoscale kinematics of a MEMS device in motion across a surface. A device under test is labeled with fluorescent nanoparticles that form a microscale constellation of near

Spin Dynamics in the Time and Frequency Domain

September 15, 2012
Author(s)
Thomas J. Silva
The current status of experimental approaches to analyze the spin wave dynamics in ferromagnetic nanoscale structures is reviewed. Recent developments in frequency- and field swept spectroscopy to determine the resonant response of nanoscale ferromagnets

UV-induced photochemical transformations of citrate capped silver nanoparticle suspensions

September 14, 2012
Author(s)
Justin M. Gorham, Robert I. MacCuspie, Kate L. Klein, D H. Fairbrother, Richard D. Holbrook
Due to the increasing use of silver nanoparticles (AgNPs) in consumer products, it is essential to understand how variables, such as light exposure, may change the physical and chemical characteristics of AgNP suspensions. To this end, the effect of 300 nm

Renormalization of the graphene dispersion velocity determined from scanning tunneling spectroscopy

September 11, 2012
Author(s)
Joseph A. Stroscio, Jungseok Chae, Nikolai B. Zhitenev, Suyong Jung, Andrea F. Young, Cory Dean, Yuanda Gao, Kenji Watanabe, Takashi Taniguchi, James Hone, Kenneth L. Shepard, Philip Kim, Lei Wang
In most metals, electrons behave as non-interacting quasiparticles with renormalized dynamical properties in the presence of electron interactions. Historically, many measurements are capable to probe the effect of interactions at the Fermi energy

Evaluation of viability and proliferation profiles on macrophages treated with silica nanoparticles in vitro via plate-based, flow cytometry, and Coulter counter assays

September 3, 2012
Author(s)
Simona Bancos, De-Hao D. Tsai, Vincent A. Hackley, J L. Weaver, Katherine M. Tyner
Nanoparticles (NPs) are known to interfere with many high throughput cell viability and cell proliferation assays, which complicates the assessment of their potential toxic effects. The aim of this study was to compare viability and proliferation results

Disentangling the effects of polymer coatings on silver nanoparticle agglomeration, dissolution, and toxicity to determine mechanisms of nanotoxicity

September 1, 2012
Author(s)
Justin M. Zook, Melissa D. Halter, Danielle Cleveland, Stephen E. Long
Silver nanoparticles (AgNPs) are frequently coated by a variety of polymers, which may affect various intertwined mechanisms of toxicity, including agglomeration and dissolution rate. Here, we measure how citrate, dextran, poly(ethylene glycol) (PEG)

Measuring Single-Walled Carbon Nanotube Length Distributions from Diffusional Trajectories

August 27, 2012
Author(s)
Jason Streit, Sergei M. Bachilo, Anton V. Naumov, Constantine Y. Khripin, Ming Zheng, R B. Weisman
A new method is demonstrated for measuring the length distributions of dispersed single-walled carbon nanotube (SWCNT) samples by analyzing diffusional motions of many individual nanotubes in parallel. In this method, termed Length Analysis by Nanotube

Microwave Measurements and Systematic Circuit-Model Extraction of Nanowire Metal Semiconductor Field Effect Transistors

August 24, 2012
Author(s)
Dazhen Gu, Thomas M. Wallis, Pavel Kabos, Paul T. Blanchard, Kristine A. Bertness, Norman A. Sanford
We present detailed on-wafer scattering parameter measurements and equivalent circuit modeling of metal semiconductor field effect transistor (MESFET) that incorporates a GaN nanowire (NW). A systematic procedure is established to extract intrinsic model

A near-field scanning microwave microscope for characterization of inhomogeneous photovoltaics

August 10, 2012
Author(s)
Joel C. Weber, Kristine A. Bertness, John B. Schlager, Norman A. Sanford, Atif A. Imtiaz, Thomas M. Wallis, Pavel Kabos, Kevin J. Coakley, Victor Bright, Lorelle M. Mansfield
We present a near field scanning microwave microscope (NSMM) optimized for imaging photovoltaic samples. Our system incorporates a cut Pt-Ir tip inserted into an open ended coaxial cable to form a weak resonator, allowing the microwave reflection S11

Summary Report of Research on TiO2 Nanomaterial

August 3, 2012
Author(s)
Vincent A. Hackley
Report summarizes study whose purpose was to optimize and validate a standardized and reproducible approach for the preparation of TiO2 nanoparticle dispersions in relevant biological and environmental test media, using an industrially relevant powder form

Magnetic Particle Imagining with a Cantilever Detector

July 23, 2012
Author(s)
Jacob W. Alldredge, John M. Moreland
We present a novel imaging method for the measuring the position and magnetic moment of single micrometer scale particles. Our technique is based on magnetic force microscopy (MFM) with a magnetically hard magnetic tip in a uniform opposing field. By
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