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Search Publications

NIST Authors in Bold

Displaying 22776 - 22800 of 73697

Viscoelastic and poroelastic relaxations of polymer-loaded hydrogels

July 5, 2012
Author(s)
Blessing Deeyaa, Christopher Stafford, Edwin Chan, Peter M. Johnson
In this work, we study the viscoelastic and poroelastic contributions on the relaxation behavior of a polymer-loaded hydrogel using a recently develop Poroelastic Relaxation Indentation (PRI) measurement technique. By applying a generalized relaxation

Observation of a superfluid Hall effect

July 3, 2012
Author(s)
Lindsay J. LeBlanc, Karina K. Jimenez Garcia, Ross A. Williams, Matthew C. Beeler, Abigail R. Perry, William D. Phillips, Ian B. Spielman
Measurement techniques based upon the Hall effect are essential tools in condensed matter physics. Here, we report the first observation of a Hall effect in an ultracold gas of neutral atoms, revealed by measuring Bose-Einstein condensate's transport

100 Years of Superconductivity

July 2, 2012
Author(s)
Richard L. Kautz
The 100th anniversary of the discovery of superconudctivity by Heike Kamerlingh Onnes was celebrated in 2011 at the Superconductivity Centennial Conference held in The Hague. 100 Years of Superconductivity is a product of that celebration, but it's far

In-situ Polarized 3He system for the Magnetism Reflectometer at the Spallation Neutron Source

July 2, 2012
Author(s)
Thomas R. Gentile, X Tong, C Y. Jiang, V Lauter, H. Ambaye, D. Brown, L Crow, R J. Goyette, W-T Lee, A. Parizzi
We report on the in-situ polarized 3He neutron polarization analyzer developed for the time-of-flight Magnetism Reflectometer (MAGICS) at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory (ORNL). Using the spin exchange optical pumping

International time and frequency comparisons in real time: recent results

July 2, 2012
Author(s)
Michael A. Lombardi, J. Mauricio Lopez-Romero, Nelida Diaz-Munoz, Eduardo de Carlos Lopez
Within the Sistema Interamericano de Metrologia (SIM) region, a time comparison network, SIMTN, has been developed. The SIMTN continuously compares the time scales of SIM members and publishes measurement results in near real-time. The measurements are

More Durable or Vulnerable? --- Effect of Nanoparticles on Long-Term Performance of Polymeric Nanocomposites during UV Exposure

July 2, 2012
Author(s)
Xiaohong Gu, Minhua Zhao, Stephanie S. Watson, Tinh Nguyen, Joannie W. Chin, Jonathan W. Martin, Dongmei Zhe, Guodong Chen
Polymers are widely used as exterior coatings in buildings, bridges, aircrafts, and automobiles for both protection and aesthetic purposes. However, the sustainability and service life of the applied coatings is limited due to the photodegradation of

Pigment and Nanofiller Photoreactivity Database

July 2, 2012
Author(s)
Stephanie S. Watson, I-Hsiang Tseng, Tarek Marray, Bastien T. Pellegrin
The service life and durability of nanocomposites that contain fillers are affected by photocatalytic properties of these fillers, particularly narrow band gap metal oxides (NBMOs) such as titanium dioxide (TiO2). When illuminated with ultraviolet (UV)

The Permanent Magnet System for NIST-4

July 2, 2012
Author(s)
Stephan Schlamminger
At the National Institute of Standards and Technology a new watt balance, NIST-4, is currently being designed. This apparatus will be used to realize the base unit of mass after the redefinition of the SI has taken effect. As a realization device, NIST-4

A Digital-to-Analog Converter with a Voltage Standard Reference

July 1, 2012
Author(s)
Alain Rufenacht, Charles J. Burroughs, Samuel Benz, Paul Dresselhaus
Commercially available 20-bit digital to analog converters (DACs) have the potential to impact the field of low frequency voltage metrology. We measured a linearity of ±6 µV (±0.6 µV/V full scale) over the 10 V range for such a DAC with a Zener voltage

A Direct Comparison System for Power Calibration up to 67 GHz*

July 1, 2012
Author(s)
Thomas M. Wallis, Thomas P. Crowley, Denis X. LeGolvan, Ronald A. Ginley
A direct comparison system for calibration of power sensors with 1.85 mm precision coaxial connectors up to 67 GHz has been developed. The comparison is implemented in two frequency bands. Between 10 MHz and 50 GHz, power sensors with 2.4 mm coaxial

Calibration Techniques for Scanning Microwave Microscopy

July 1, 2012
Author(s)
Thomas M. Wallis, Atif A. Imtiaz, Alexandra Curtin, Pavel Kabos, H. P. Huber, Joseph J. Kopanski, F. Kienberger
Two techniques are described for calibrating a scanning microwave microscope (SMM). The first technique enables spatially-resolved absolute capacitance measurements on the attofarad-to-femtofarad scale. The second technique enables profiling or dopant

Electromagnetic Properties of Iron Oxide Corrosion Product Powders at Radio Frequencies

July 1, 2012
Author(s)
Sung Kim, Jack T. Surek, James R. Baker-Jarvis, Virgil Provenzano
We calculated the refractive index from Sparameter data for corrosion samples tested in waveguide from 12.4 GHz to 110 GHz. This approach minimizes the modal noise often seen in derived permittivity and permeability for low-loss samples in this range. Also

Flat frequency response in the electronic measurement of the Boltzmann constant

July 1, 2012
Author(s)
Jifeng Qu, Samuel Benz, Yang Fu, Jianqiang Zhang, Horst Rogalla, Alessio Pollarolo
A new quantum voltage calibrated Johnson noise thermometer (JNT) was developed at NIM to demonstrate the electrical approach that determines the Boltzmann constant k by comparing electrical and thermal noise power. A measurement with integration period of
Displaying 22776 - 22800 of 73697
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