Neutron Diffraction Experiments
نویسنده
چکیده
This ISEN award supported research toward improving the energy efficiency of actuators. The focused research objective was to develop next-generation shape memory alloy (SMA) models and structures, to demonstrate this new technology in targeted near-term applications on airplanes. Two research avenues were pursued to enable development of this new technology: 1) neutron diffraction experiments to acquire fundamental understanding of SMAs necessary for optimizing their energy efficiency, and 2) the use of a device-level model to understand the benefits and best designs for SMA actuation structures. An additional goal was to secure additional funding for this work. The results of this research have been used in six proposals: one was funded, one was not funded but is being revised and submitted to a different NSF program this fall, three are still in review, and the final proposal is expected to result in secured funding within the next few weeks. Regarding peer reviewed publications supported by this work, two were published this year in Acta Materialia [1, 2], and several others are in preparation. Finally, several invited conference presentations and one ASME conference paper have been given or submitted [3-5][Stebner, 2011 #19], and three proposals to use government laboratory facilities were accepted.
منابع مشابه
Structure determination and Phase Analysis by the use of Neutron diffraction
Neutron diffraction has proven to be an indispensable and highly significant tool since its development 60 years ago. The neutron has unique properties that yield distinct information unavailable otherwise. Chief among these properties is the relative uniformity of the neutron scattering power of atoms across the periodic table, allowing the accurate structure determination of materials compose...
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This paper introduces a two-dimensional extension of the well established Rietveld refinement method for modeling neutron time-of-flight powder diffraction data. The novel approach takes into account the variation of two parameters, diffraction angle 2θ and wavelength λ, to optimally adapt to the varying resolution function in diffraction experiments. By doing so, the refinement against angular...
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A combined neutron imaging and neutron diffraction facility, IMAT, is currently being built at the pulsed neutron spallation source ISIS in the U.K. A supermirror neutron guide is required to combine imaging and diffraction modes at the sample position in order to obtain suitable time of flight resolutions for energy selective imaging and diffraction experiments. IMAT will make use of a straigh...
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The theory of magnetic symmetry in quasicrystals is used to characterize the nature of magnetic peaks, expected in elastic neutron diffraction experiments. It is established that there is no symmetry-based argument which forbids the existence of quasiperiodic long-range magnetic order. Suggestions are offered as to where one should look for the simplest kinds of antiferromagnetic quasicrystals.
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Polarised neutron diffraction experiments conducted at 4.2 K on Cs(3)CoCl(5) crystals have been analysed by using a four-dimensional model Hilbert space made of ab initio n-electron wave functions of the CoCl(4)(2-) molecular ion. Two spin-orbit mixing coefficients and several configuration interaction coefficients have been optimized by fitting calculated magnetic structure factors to experime...
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X-ray diffraction data cannot provide anisotropic displacement parameters (ADPs) for H atoms, a major outstanding problem in charge-density analysis of molecular crystals. Although neutron diffraction experiments are the preferred source of this information, for a variety of reasons they are possible only for a minority of materials of interest. To date, approximate procedures combine rigid-bod...
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