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Search Publications

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Displaying 19176 - 19200 of 73960

Ultrafast THz photoconductivity of photovoltaic polymer-fullerene blends: a comparative study correlated with photovoltaic device performance

October 10, 2014
Author(s)
Edwin J. Heilweil, Jin Zuanming, Dominik Gehrig, Clare Dyer-Smith, Frederic Laquai, Mischa Bonn, Dmitry Turchinovich
Ultrafast photo-induced carrier dynamics in prototypical low band-gap polymer:fullerene photovoltaic blend films PTB7:PC70BM and P3HT:PC70BM is investigated using ultrafast terahertz (THz) spectroscopy. The sub-picosecond (ps) and few-ps decays of THz

A Cybersecurity Testbed for Industrial Control Systems

October 9, 2014
Author(s)
Richard Candell, Keith A. Stouffer, Dhananjay Anand
The National Institute of Standards and Technology (NIST) is developing a cybersecurity testbed for industrial control systems (ICS). The goal of this testbed is to measure the performance of an ICS when instrumented with cybersecurity protections in

Kitaev chains with long-range interactions

October 9, 2014
Author(s)
Davide Vodola, Luca Lepori, Elisa Ercolessi, Alexey Gorshkov, Guido Pupillo
We propose and analyze a generalization of the Kitaev chain for fermions with long-range p-wave pairing, which decays with distance as a power-law with exponent $\alpha$. Using the integrability of the model, we demonstrate the existence of two types of

Neutron Scattering Studies of the Ferroelectric Distortion and Spin Dynamics in the Type-1 Multiferroic Perovskite Sr 0.56 Ba 0.44 MnO 3

October 9, 2014
Author(s)
Daniel K. Pratt, Jeffrey W. Lynn, James Mais, Omar Chmaissem, Dennis E. Brown, Stanislaw Kolesnik, Bogdan Dabrowski
The magnetic order, spin dynamics, and crystal structure of the multiferroic Sr 0.56Ba 0.44MnO 3 have been investigated using neutron and x-ray scattering. Ferroelectricity develops at T c=305 K with a polarization of 4.2 υC/cm 2 associated with the

Performance of Portable Radios Exposed to Elevated Temperatures

October 9, 2014
Author(s)
Michelle K. Donnelly, William F. Young, Dennis G. Camell
This study investigates the performance issues associated with the use of handheld portable radios by fire fighters working in elevated temperature environments. Radios may be vulnerable to elevated temperatures that can be encountered during fire fighting

Solid State Lighting Annex 2013 Interlaboratory Comparison Final Report

October 9, 2014
Author(s)
Yoshihiro Ohno
The Interlaboratory Comparison, IC2013, for measurement of solid state lighting (SSL) products was conducted by International Energy Agency (IEA) 4E SSL Annex between October 2012 and August 2013. 55 laboratories from 18 countries participated in this

Influence of Chemical Straightening on the Stability of Drugs of Abuse in Hair

October 8, 2014
Author(s)
Jeanita Pritchett, Karen W. Phinney
Chemical straightening, also known as a relaxer, is ubiquitously used among African American women to obtain straighter hair compared with their natural tresses. This study focused on the stability of drugs of abuse in hair after a single application of

On Cascading Failures and Countermeasure based on Energy Storage in the Smart Grid

October 8, 2014
Author(s)
Xing Chen, Wei Yu, David W. Griffith, Nada T. Golmie, Guobin Xu, Chao Lu
Recently, there are growing concerns about smart grid security and resilience. The performance of smart grid may suffer from component failures or targeted attacks. A sophisticated adversary may target critical components in a smart grid, leading to

On Statistical Modeling and Forecasting of Energy Usage in Smart Grid

October 8, 2014
Author(s)
Wei Yu, Dou An, David W. Griffith, Qingyu Yang, Guobin Xu
Developing effective energy resource management in the smart grid is challenging because the entities in both the demand and supply sides experience various uncertainties. This paper addresses the issue of quantifying uncertainties on the energy demand

Optimizing Passive Quantum Clocks

October 8, 2014
Author(s)
Michael J. Mullan, Emanuel Knill
We describe protocols for passive atomic clocks based onquantum interrogation of the atoms. Unlike previous techniques, our protocols are adaptive and take advantage of prior information about the clock's state. To reduce deviations from an ideal clock

Sensitivity Analysis of Installation Faults on Heat Pump Performance

October 8, 2014
Author(s)
Piotr A. Domanski, Hugh Henderson, William V. Payne
Numerous studies and surveys indicated that typically-installed HVAC equipment operates inefficiently and wastes considerable energy due to different installation errors (faults), e.g., improper refrigerant charge, incorrect airflow, oversized equipment

Collapse and revivals for systems of short-range phase coherence

October 7, 2014
Author(s)
Khan W. Mahmud, Lei Jiang, Philip R. Johnson, Eite Tiesinga
We predict the existence of novel collapse and revival oscillations that are a distinctive signature of the short-range off-diagonal coherence associated with particle-hole pairs in Mott insulator states. Starting with an atomic Mott state in a one

Evaluating CT for Metrology: The Influence of Material Thickness on Measurements

October 7, 2014
Author(s)
Joseph Schlecht, Eric Ferley, Shaun COUGHLIN , Steven D. Phillips, Vincent Lee, Craig M. Shakarji
X-ray imaging provides a non-destructive means to measure internal features of a workpiece, and CT offers unique capabilities for internal measurements in 3-D. However, due to the computational nature of CT and its indirect measurement process, assessing

Comb-calibrated laser ranging for three-dimensional surface profiling with micrometer-level precision at a distance

October 6, 2014
Author(s)
Esther Baumann, Fabrizio R. Giorgetta, Jean-Daniel Deschenes, William C. Swann, Ian R. Coddington, Nathan R. Newbury
Non-contact surface mapping at a distance is interesting in diverse applications including industrial metrology, manufacturing, forensics, and artifact documentation and preservation. Frequency modulated continuous wave (FMCW) laser detection and ranging

New National Air-Kerma Standard for Low-Energy Electronic Brachytherapy Sources

October 6, 2014
Author(s)
Stephen M. Seltzer, C M. O'Brien, Michael G. Mitch
The purpose of this report is to document the NIST air-kerma measurement standard for the electronic brachytherapy sources, i.e., the Axxent sources of Xoft, Inc., which operate at tube potentials of 50 kV and anode currents of 300 μA. The use of such

Phase-Sensitive Detection of Spin Pumping via the ac Inverse Spin Hall Effect

October 6, 2014
Author(s)
Thomas J. Silva, Justin M. Shaw, Hans T. Nembach, Mathias A. Weiler
Sources of pure spin currents are a fundamental building block of spintronic devices. In ferromagnet/normal metal heterostructures, spin currents are generated at ferromagnetic resonance. This is known as spin pumping, where spin currents of both dc and ac

Progress toward Radiation-Pressure-Based Measurement of High-Power Laser Emission - Under Policy Review

October 6, 2014
Author(s)
Paul A. Williams, Joshua A. Hadler, Daniel King, Robert Lee, Frank C. Maring, Gordon A. Shaw, Nathan A. Tomlin, John H. Lehman, Marla L. Dowell
We present an overview of our efforts toward using optical radiation pressure as a means to measure optical power from high-power lasers. Early results with measurements ranging from tens of watts to 92 kW prove the concept, but validation uncertainties
Displaying 19176 - 19200 of 73960
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