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Displaying 17726 - 17750 of 74219

Origin of the Charge Gap in LaMnPO

November 18, 2014
Author(s)
D. E. McNally, J. W. Simonson, K. W. Post, Z. P. Yin, M. Pezzoli, G. J. Smith, V. Leyva, C. Marques, L. DeBeer-Schmitt, A. I. Kolesnikov, Yang Zhao, Jeffrey W. Lynn, D. N. Basov, G. Kotliar, M. C. Aronson
We present inelastic neutron scattering and magnetization measurements of the antiferromagnetic insulator LaMnPO that are well described by a Heisenberg spin model. These measurements are consistent with the presence of two-dimensional magnetic

Structure and Magnetic Properties of the a-NaFeO 2 -Type Honeycomb Compound Na 3 Ni 2 BiO 6

November 15, 2014
Author(s)
Elizabeth M. Seibel, J. H. Roudebush, Hui Wu, Qingzhen Huang, Mazhar N. Ali, Huiwen Ji, R. J. Cava
We present the structure and magnetic properties of Na 3Ni 2BiO 6, which is an ordered variant of the α-NaFeO 2 structure type. This layered compound has a 2:1 ordering of (Ni 2+/Bi 5+)O 6 octahedra within the a-b plane and sodium in octahedra between the

A study of the adhesive foot of the gecko

November 14, 2014
Author(s)
Elmar Kroner, Chelsea S. Davis
In recent years, hundreds of scientific studies have been published regarding gecko-inspired adhesives. The primary reason for this increasing interest lies in the unique properties which are combined in the adhesive system of the gecko: this natural

Broadband Noise Limit in the Photodetection of Ultralow Jitter Optical Pulses

November 14, 2014
Author(s)
Franklyn J. Quinlan, W. Sun, Tara M. Fortier, Jean-Daniel Deschenes, Yang Fu, Scott A. Diddams, Joe Campbell
Applications with optical atomic clocks and precision timing often require the transfer of optical frequency references to the electrical domain with extremely high fidelity. Here we examine the impact of photocarrier scattering and distributed absorption

Hardening Structures to Resist Wildland-Urban (WUI) Fire Exposures

November 14, 2014
Author(s)
Samuel L. Manzello
Wildfires that spread into communities, referred to as Wildland-Urban Interface (WUI) fires, have destroyed communities throughout the world. In the USA, over 46 million homes in 70,000 communities are at risk of WUI fires [1-2]. Historically, fire safety

Hydrocarbon Flame Inhibition by C3H2F3Br (2-BTP)

November 14, 2014
Author(s)
Valeri I. Babushok, Gregory T. Linteris, Donald R. Burgess Jr., Patrick T. Baker
The kinetic mechanism of hydrocarbon flame inhibition by the potential halon replacement 2-BTP has been assembled, and is used to study its effects on premixed methane-air flames. Simulations with varying CH4-air stoichiometry and agent loading have been

Light Induced Gauge Fields for Ultracold Neutral Atoms

November 14, 2014
Author(s)
Ian B. Spielman
Ultracold neutral atoms, with their simple interactions along with well characterized, highly tunable system parameters, are an ideal platform for realizing and then quantitatively studying many-body phenomena. Many-body physics is perhaps most familiar in

Accurate determination of the size distribution for polydisperse, cationic metallic nanomaterials by asymmetric-flow field flow fractionation

November 13, 2014
Author(s)
Julien C. Gigault, Thao M. Nguyen, John M. Pettibone, Vincent A. Hackley
In this work we have developed and validated a methodology for determining the size distribution in polydisperse cationic nanoparticle (NP) samples using asymmetric-flow field flow fractionation (A4F), where known compositional influence of previously used

PBTI-Induced Random Timing Jitter in Circuit-Speed Random Logic

November 13, 2014
Author(s)
Jiwu Lu, Canute I. Vaz, Guangfan Jiao, Jason P. Campbell, Jason T. Ryan, Kin P. Cheung, Gennadi Bersuker, Chadwin D. Young
Accurate reliability predictions of real world digital logic circuits rely heavily on the relevancy of device level testing. In the case of bias temperature instability (BTI), where recovery plays a significant role, a leap of faith is taken to translate

Simulation of a Fire in a Hillside Residential Structure - San Francisco, CA

November 13, 2014
Author(s)
Kristopher J. Overholt, Craig G. Weinschenk, Daniel M. Madrzykowski
Fire Dynamics Simulator (FDS), which is a fire model that is developed and maintained by the National Institute of Standards and Technology (NIST), was used to provide insight into the dynamics of a fire that occurred on June 2, 2011, within a multi-level

Influence of the central mode and soft phonon on the microwave dielectric loss near the strain-induced ferroelectric phase transitions in Sr n+1 uTi n uO 3n+1 u*

November 12, 2014
Author(s)
V. Goian, S. Kamba, D Nuzhnyy, Nathan Orloff, T. Birol, C.-H Lee, D. G. Schlom, James Booth
Recently, Lee et al. [1] used1% tensile strain to induce a ferroelectic instability in thin films of Srdn+1uTi nuO 3n+1u (n=1-6) phases. They showed that the Curie temperature T cu gradually increased with n, reaching 180 K for Sr7Ti6O19 (n=6). The

A Method of Determining Sphere Center to Center Distance Using Laser Trackers For Evaluating Laser Scanners.

November 11, 2014
Author(s)
Prem K. Rachakonda, Balasubramanian Muralikrishnan, Vincent D. Lee, Daniel S. Sawyer, Steven D. Phillips, John Palmateer
The Dimensional Metrology Group (DMG) at the National Institute of Standards and Technology (NIST) is involved in the development of documentary standards for volumetric performance evaluation of laser scanners. Typical evaluation of these scanners

A thermodynamic investigation of the cellulose allomorphs: cellulose(am), cellulose I?(cr), cellulose II(cr), and cellulose III(cr)

November 11, 2014
Author(s)
Robert N. Goldberg, Jacob Schliesser, Ashutosh Mittal, Stephen R. Decker, Ana Filipa L. Santos, Vera L. Freitas, Aaron A. Urbas, Brian E. Lang, Christian Heisse, Maria D. Ribeiro da Silva, Brian F. Woodfield, Rui Katahira, Wei Wang, David K. Johnson
The thermochemistry of samples of amorphous cellulose, cellulose I, cellulose II, and cellulose III was studied by using oxygen bomb calorimetry, solution calorimetry in which the solvent was cadoxen, and with a Physical Property Measurement System (PPMS)

An Access Control Scheme for Big Data Processing

November 11, 2014
Author(s)
Chung Tong Hu, Timothy Grance, David F. Ferraiolo, David R. Kuhn
Access Control (AC) systems are among the most critical of network security components. A system's privacy and security controls are more likely to be compromised due to the misconfiguration of access control policies rather than the failure of

Laser scanner two-face errors on spherical targets

November 11, 2014
Author(s)
Balasubramanian Muralikrishnan, Katharine M. Shilling, Daniel S. Sawyer, Prem K. Rachakonda, Vincent D. Lee, Steven D. Phillips, Geraldine S. Cheok, Kamel S. Saidi
Geometric misalignments within the construction of a laser scanner such as offsets, tilts, and eccentricities, result in systematic errors in the measured point coordinates (range and angles). Many of these sources of error are sensitive to two-face

Nonproportionality in the scintillation light yield of bismuth germanate

November 11, 2014
Author(s)
Thomas R. Gentile, M J. Bales, H Breuer, T E. Chupp, Kevin J. Coakley, R L. Cooper, Jeffrey S. Nico, B. O'Neill
We present measurements of nonproportionality in the scintillation light yield of bismuth germanate (BGO) for gamma-rays with energies between 6 keV and 662 keV. The scintillation light was read out by avalanche photodiodes (APDs) with both the BGO

POINT REMOVAL FOR FITTING SPHERES TO 3-D LASER SCANNER DATA

November 11, 2014
Author(s)
Katharine M. Shilling, Balasubramanian Muralikrishnan, Daniel S. Sawyer
The proliferation of laser scanners in a number of industries such as the metrology of large artifacts, digitization and reverse engineering, historical preservation and archiving has led to the need for documentary Standards to establish and compare the
Displaying 17726 - 17750 of 74219