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Displaying 20276 - 20300 of 73960

Top-Down Fabrication of Large-Area GaN Micro and Nano Pillars

February 19, 2014
Author(s)
Albert Davydov, Ratan K. Debnath, B. Wen, Dipak Paramanik, Abhishek Motayed, M. King
Large-area gallim nitride (GaN) nanopillars (NPs) arrays were fabricated by plasma etching of lithographically patterned GaN thin-film grown on Si substrate. Deep-UV lithography, inductively-coupled plasma etching, and follow-on chemical treatments were

Complex Structures of Different CaFe 2 As 2 Samples

February 18, 2014
Author(s)
Bayrammurad Saparov, Claudia Cantoni, Minghu Pan, Thomas C. Hogan, William D. Ratcliff, Stephen D. Wilson, Katharina Fritsch, Bruce D. Gaulin, Athena S. Sefat
We use temperature-dependent X-ray and neutron diffraction, low-temperature scanning tunneling microscopy, and room-temperature scanning-transmission electron-microscopy, to investigate the interplay between magnetism and crystal structures in three CaFe

Dependence of Soot Optical Properties on Particle Morphology: Measurements and Model Comparisons

February 18, 2014
Author(s)
James Radney, Rian You, Xiaofei Ma, Joseph Conny, Michael R. Zachariah, Joseph T. Hodges, Christopher D. Zangmeister
We measure the mass-specific absorption and extinction cross sections for laboratory-generated soot aerosols. Two soot morphologies are investigated, both comprising fractal aggregates of nearly spherical monomers. The first type consists of monomer chains

In situ temperature measurements for selective epitaxy of GaN nanowires

February 17, 2014
Author(s)
Kristine A. Bertness, Matthew D. Brubaker, Todd E. Harvey, Shannon M. Duff, Aric W. Sanders, Norman A. Sanford
We demonstrate with spatially resolved, in situ temperature measurements and ex situ reflectance measurements that differences in appearance for masked and unmasked surfaces on patterned growth substrates arise from wavelength-dependent emissivity

Role of salt on adhesion of an epoxy/aluminium (oxide) interface in aqueous environments

February 16, 2014
Author(s)
Christopher C. White, Kar T. Tan, Donald L. Hunston, Justin M. Gorham, Aaron M. Forster, Vogt D. Bryan
The durability of adhesive joints in hostile environments is a major area of concern in structural adhesive bonding. Therefore, understanding the mechanics and mechanisms of degradation of adhesive joints is a key factor for more extensive use in future

Annual Report of the National Earthquake Hazards Reduction Program for Fiscal Year 2012

February 14, 2014
Author(s)
John(Jack) R. Hayes Jr., Steven L. McCabe, Edward Laatsch, Joy Pauschke, Bill Leith, John Filson, Tina M. Faecke
This report about the National Earthquake Hazards Reduction Program (NEHRP) during fiscal year 2012 is submitted to Congress by the Interagency Coordinating Committee (ICC) of NEHRP, as required by the National Earthquake Hazards Reduction Act of 1977 (42

Hysteresis in Quantized Superfluid Atomtronic Circuit

February 14, 2014
Author(s)
Stephen P. Eckel, Jeffrey Lee, Fred Jendrzejewski, Noel Murray, Charles W. Clark, Christopher J. Lobb, William D. Phillips, Edwards Mark, Gretchen K. Campbell
Atomtronics is an emerging interdisciplinary field that seeks new functionality by creating devices and circuits where ultra-cold atoms play a role analogous to the electrons in electronics. Hysteresis in atomtronic circuits may prove to be a crucial

Role of Random Electric Fields in Relaxors

February 14, 2014
Author(s)
Daniel P. Phelan, Christopher Stock, Jose Rodriguez Rivera, Songxue Chi, Juscelino Leao, Xifa Long, Yujuan Xie, Alexei A. Bokov, Zuo-Guang Ye, Panchapakesan Ganesh, Peter M. Gehring
Pb(Zr 1¿xTi x)O 3 (PZT) and Pb[(Mg 1/3Nb 2/3) 1¿xTi x]O 3 (PMN-xPT) are complex lead-oxide perovskites that display exceptional piezoelectric properties for pseudo-rhombohedral compositions near a tetragonal phase boundary. In PZT these compositions are

Metrological challenges introduced by new tolerancing standards

February 13, 2014
Author(s)
Ed Morse, Yue Peng, Vijay Srinivasan, Craig M. Shakarji
The recent release of ISO has provided designers with a richer set of specification tools for the size of part features, so that various functional requirements can be captured with greater fidelity [2]. However, these tools also bring new challenges and

Supercontinuum generation in an on-chip silica waveguide

February 13, 2014
Author(s)
Scott A. Diddams, Dong Yoon Oh, David Sell, Hansuek Lee, Ki Youl Yang, Kerry J. Vahala
Supercontinuum generation is demonstrated in an on-chip silica spiral waveguide by launching 180-fs pulses from an optical parametric oscillator at the center wavelength 1330 nm. With a coupled pulse energy of 2.17 nJ, the broadest spectrum in the

Framework for Improving Critical Infrastructure Cybersecurity, Version 1.0

February 12, 2014
Author(s)
Adam Sedgewick
The national and economic security of the United States depends on the reliable functioning of critical infrastructure. Cybersecurity threats take advantage of the increased complexity and connectivity of critical infrastructure systems, placing the Nation

Polarized 3HE Spin Filters for Neutron Science

February 12, 2014
Author(s)
Thomas R. Gentile, Wei-Chen N. Chen
The large spin dependence of the absorption cross section for neutrons by 3He gas provides a method to polarize neutron beams. For certain applications, such polarized 3He-based neutron "spin filters" have advantages over conventional neutron optical

Environmental Health in Low Energy Buildings Topic Overview

February 11, 2014
Author(s)
Steven J. Emmerich, Hal Levin
Besides providing thermal comfort and acceptable indoor environmental quality (IEQ), the designers of buildings and other enclosed spaces are increasingly challenged to provide a healthy environment in an energy efficient manner. Increasing pressure to

The IAQ and Energy Impacts of Reducing Formaldehyde Emissions in Commercial Building

February 11, 2014
Author(s)
Lisa C. Ng, Andrew K. Persily, Steven J. Emmerich, Kevin Y. Teichman
Heating, ventilating, and air conditioning (HVAC) systems in buildings are designed to provide thermally comfortable conditions and to maintain acceptable indoor air quality (IAQ). At the same time, the operating costs of HVAC systems are often a large

Bloch oscillations collapse and revival of interacting bosons in an optical lattice

February 10, 2014
Author(s)
Khan W. Mahmud, Lei Jiang, Eite Tiesinga, Philip Johnson
We study the dynamics of interacting superfluid bosons in a one dimensional vertical optical lattice after a sudden increase of the lattice potential depth. We show that this system can be exploited to investigate the effects of strong interactions on

Filter Material Effects on Particle Absorption Characteristics

February 10, 2014
Author(s)
Cary Presser, Joseph M. Conny, Ashot Nazarian
The absorption coefficient and mass specific absorption cross section were determined for nigrosin-laden quartz, Teflon, and polycarbonate filters in inert surroundings at different steady-state temperatures and particle mass loadings. The objective was to

The U.S. Manufacturing Value Chain: An International Perspective

February 10, 2014
Author(s)
Douglas Thomas
This report uses input-output data from the World Input-Output Database along with the methods developed by Wassily Leontief to track the intermediate goods and services used in national manufacturing industries. Specifically, it examines the extent that

Ultrafast optical properties of lithographically defined quantum dot amplifiers

February 10, 2014
Author(s)
Luis Miaja Avila, Varun B. Verma, James J. Coleman, Richard P. Mirin, Kevin L. Silverman
We measure the ultrafast optical response of lithographically defined quantum dot amplifiers at 40 K. Recovery of the gain mostly occurs in less than 1 picosecond, with some longer-term transients attributable to carrier heating. Recovery of the absorption

Properties of TiN for Detector and Amplifier Applications

February 8, 2014
Author(s)
Jiansong Gao, Michael R. Vissers, Martin O. Sandberg, Dale Li, Hsiao-Mei Cho, Clint Bockstiegel, Ben Mazin, Henry G. Leduc, Saptarshi Chaudhuri, David P. Pappas, K D. Irwin
We have experimentally explored and carefully characterized the important properties of TiN, including the resistivity, nonlinear kinetic inductance, the anomalous electro-dynamical response, and the two-level-system induced frequency shift and noise. We
Displaying 20276 - 20300 of 73960
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