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Displaying 576 - 600 of 807

High-Accuracy Measurements of the Vapor Pressure of Ice Referenced to the Triple Point

December 6, 2013
Author(s)
Katarzyna E. Bielska, Daniel K. Havey, Gregory E. Scace, D Lisak, Allan H. Harvey, Joseph T. Hodges
The vapor pressure of hexagonal (Ih) ice was measured over the temperature range 175 K to 253.4 K and referenced to the value at the triple point of water. This experiment combined a highly accurate humidity generation system containing an ice-coated

Improved Determination of the Neutron Lifetime

December 2, 2013
Author(s)
Jeffrey S. Nico, A. T. Yue, Maynard S. Dewey, David M. Gilliam, G L. Greene, A. Laptev, William M. Snow, F. E. Wiefeldt
The most precise determination of the neutron lifetime using the beam method was completed in 2005 and reported a result of tau_n = (886.3 ± 1.2 [stat] ± 3.2 [sys]) s. The dominant uncertainties were attributed to the absolute determination of the fluence

On the Determination of Carbon by PGAA

November 10, 2013
Author(s)
Rolf L. Zeisler, Rick L. Paul, Jeffrey A. Fagan, Zsolt R?vay, Stefan S?llradl
Determination of carbon was achieved with reduction of background in prompt gamma activation analysis.

Effect of Supercritical Carbon Dioxide on the Thermodynamics of Model Styrene-Acrylonitrile Copolymer-Poly(methyl methacrylate) Blends Studied by Small-Angle Neutron Scattering

July 25, 2013
Author(s)
Sebnem Inceoglu, Nicholas P. Young, Andrew J. Jackson, Steven Kline, Stephane Costeux, Nitash P. Balsara
Small-angle neutron scattering was used to study a binary blend of styrene-acrylonitrile copolymer (SAN) and deuterated poly(methyl methacrylate) (dPMMA), as wellas a multicomponent mixture of SAN, dPMMA, and supercritical carbon dioxide (scSO 2). The

Improving quantitative neutron radiography through image restoration

July 20, 2013
Author(s)
Daniel S. Hussey, Elias M. Baltic, Kevin J. Coakley, David L. Jacobson
This in-situ study examines the water content in polymer electrolyte fuel cells (PEFCs) using neutron radiography. Various conditions such as different polytetraflouroethylene (PTFE) loadings in the gas diffusion media including the micro-porous layer (MPL

Formation of Disk- and Stacked Disk-Like Self-Assembled Morphologies from Cholesterol Functionalized Aliphatic Polycarbonate Containing Amphiphilic Diblock Copolymers

June 10, 2013
Author(s)
Vivek M. Prabhu, Shrinivas Venkataraman, Ashlynn Lee, Yi Yan Yang, James Hedrick, Hareem Maune
In this study, a cholesterol functionalized aliphatic cyclic carbonate monomer, 2-(5-methyl-2-oxo-1,3-dioxane-5-carboxyloyloxy)ethyl carbamate (MTC-Chol) was synthesized. The organo-catalytic ring opening polymerization of MTC-Chol was accomplished by

Light-Wave Mixing and Scattering with Quantum Gases

May 21, 2013
Author(s)
Lu Deng, Chengjie Zhu, Edward W. Hagley
We present a general theoretical framework on light-wave mixing and scattering in quantum gases. We show that all such processes that originate from elementary excitations are stimulated Raman or hyper-Raman in nature. In the forward direction, the third

Structure and Stability of SnO2 Nanocrystals and Surface-Bound Water Species

May 8, 2013
Author(s)
Rick L. Paul, Hsiu-Wen Wang, David J. Wesolowski, Thomas E. Proffen, Lucus Vicek, Wei Wang, Lawrence F. Allard, Alexander I. Kolesnikov, Mikhail Feygenson, Lawrence M. Anovitz
The structure of SnO2 nanoparticles (avg. 5 nm diameter) with a few layers of water on the surface has been elucidated by atomic pair distribution function (PDF) methods using in situ neutron total scattering data and molecular dynamics (MD) simulations

Wide Angle Polarization Analysis with Neutron Spin Filters

April 29, 2013
Author(s)
Qiang NMN Ye, Thomas R. Gentile, Jeffrey R. Anderson, Collin L. Broholm, WangChun Chen, Z DeLand, Ross W. Erwin, C. B. Fu, John E. Fuller III, Aaron V. Kirchhoff, J. A. Rodriguez-Rivera, V. Thampy, T G. Walker, Shannon Watson
We report substantial improvements in a compact wide angle neutron spin filter system that was recently employed on the Multi-Axis Crystal Spectrometer at the Center for Neutron Research at the U.S. National Institute of Standards and Technology. The

Demonstration of Achromatic Cold-Neutron Microscope Utilizing Axisymmetric Focusing Mirrors.

April 21, 2013
Author(s)
Daniel S. Hussey, D. Liu, M. V. Gubarev, D Ramsey, David L. Jacobson, Muhammad D. Arif, D. E. Moncton, B. Khaykovich
An achromatic cold-neutron microscope with magnification 4 is demonstrated. The image-forming optics is made of nested coaxial mirrors of full figures of revolution, so-called Wolter optics. The spatial resolution, field of view, and depth of focus are

Temperature Effect on the Nanostructure of SDS Micelles in Water

April 11, 2013
Author(s)
Boualem Hammouda
Sodium dodecyl sulfate (SDS) surfactants form micelles when dissolved in water. These are formed of a hydrocarbon core and hydrophilic ionic surface. The small-angle neutron scattering (SANS) technique was used with deuterated water (D 2O) in order to

Design of remnant magnetization FeCoV films as compact, heatless neutron spin rotators

April 5, 2013
Author(s)
Michael G. Huber, M. O. Abutaleb, Dimitry A. Pushin, Charles F. Majkrzak, Muhammad Arif, D G. Cory
We introduce a design of a neutron spin rotator for applications with space and temperature constraints. These passive devices employ remnant magnetization Fe- CoV thin films and can be tuned experimentally to achieve arbitrary rotation of an incident

Event Identification in He-3 Proportional Counters Using Risetime Discrimination

April 2, 2013
Author(s)
Jeffrey S. Nico, T J. Langford, Christopher D. Bass, E J. Beise, D. K. Erwin, Craig Heimbach
We present a straightforward method for particle identification and background rejection in He-3 proportional counters for use in neutron detection. By measuring the risetime and pulse height of the preamplifier signals, one may define a region in the
Displaying 576 - 600 of 807