Aperture reflection coefficient of a parallel- plate waveguide by wedge diffraction analysis
Aperture reflection coefficient of parallel plate waveguide by wedge diffraction analysis
DIFFRACTION↗
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Results for “Diffraction”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Electron diffraction control studies of Venus Flytrap particles
Electron diffraction patterns of olivine and enstatite as control study for Venus Fly Trap rocket experiments
ELECTRON DIFFRACTION↗
Numerical results for the diffraction of a normal shock wave by a sphere and for the subsequent transient flow
Finite difference method to obtain numerical results on normal shock wave diffraction by sphere and subsequent transient flow
DIFFRACTION↗
Theoretical performance of solar cell space power systems using spectral dispersion. II - Dispersion by diffraction gratings
Calculated potential increase in solar cell array conversion efficiency with dispersion by diffraction grating
DIFFRACTION GRATING↗
Focusing hologram diffraction grating.
Interferometer producing focusing hologram diffraction grating, noting photograph of spectrum
SPECTROGRAPHY↗
X-ray diffraction analysis of cohenite from iron meteorites.
Cohenite grains from iron meteorites studied by X-ray diffraction for establishing pressure scale, using solid state recrystallization
X-RAY DIFFRACTION↗
The diffraction of H.F. radio waves by ionospheric irregularities.
Diffraction of HF radio waves by ionospheric layer containing field-aligned inhomogeneities
FIELD-ALIGNED IRREGULARITY /FAI/↗
Selected-area small-angle electron diffraction.
Selected-area small angle electron diffraction using double-condenser electron microscope, noting high resolution power
ELECTRON MICROSCOPE↗
Diffractive optics for particle velocimetry and sizing
Beam-shaping diffractive optical elements are used to create structured light patterns in fluid flows. Particle scattering results in detected signals that can be used to determine the particle size and velocity.
diffractive optics laser velocimetry↗
Diffractive Optical Elements for Spectral Imaging
Diffractive optical elements fabricated on flat and non-flat substrates frequently act as dispersive elements in imaging spectrometers. We describe the design and electron-beam fabrication of blazed and computer-generated-hologram gratings for slit and tomographic imaging spectrometers.
diffractive optics gratings spectral imaging imagi↗
Diffractive Optic Fluid Shear Stress Sensor
Light scattering off particles flowing through a two-slit inteference pattern can be used to measure the shear stress of the fluid. We have designed and fabricated a miniature diffractive optic sensor based on this principle.
fluid shear stress micro sensor non-invasive senso↗
Diffractive Optical Elements for Spectral Imaging
Diffractive optical elements fabricated on flat and non-flat substrates frequently act as dispersive elements in imaging spectrometers. We describe the design and electron-beam fabrication of blazed and computer-generated-hologram gratings for slit and tomographic imaging spectrometer.
diffractive optics gratings spectral imaging imagi↗
Diffractive Optic Fluid Shear Stress Sensor
Light scattering off particles flowing through a two-slit interference pattern can be used to measure the shear stress of the fluid. We have designed and fabricated a miniature diffractive optic sensor based on this principle.
optics↗
Diffraction Modeling of Finite Subband EFC Probing on Dark Hole Contrast with WFIRST-CGI Shaped Pupil Coronagraph
The current NASA WFIRST (Wide-Field InfraRed Survey Telescope) coronagraph instrument (CGI) design allocates two subband filters per each full science band in order to contain system complexity and cost. We present our detailed investigation results on the adequacy of such a limited number of finite subband filters in achieving broadband dark hole contrast with a shaped pupil coronagraph (SPC). The study is based on diffraction propagation modeling with realistic WFIRST optics, where each subband’s image plane electric field is estimated from pairwise pupil plane deformable mirror (DM) probing and image plane intensity averaging of the resulting fields of multiple (subband) wavelengths. Multiple subband choices and probing and control strategies are explored, including standard subband probing; mixed wavelength and/or weighted Jacobian matrix; subband probing with intensity subtraction; and extended subband probing with intensity subtraction. Overall, the investigation shows that the achievable contrast with a limited number of finite subbands is about 2~2.5x worse than the designed contrast for the current SPC. The result suggests that future shaped pupil designs should be optimized for slightly broader bandwidths than the intended science bandpasses if limited subbands are used for wavefront sensing via probing.
WFIRST↗
Application of a large space-based diffractive optical element telescope to the Terrestrial Planet-Finder Mission: design and tolerance issues
An analytical description of the scattered light from a 10 meter diameter Diffractive Optical Element lens-based telescope operating at 1 micron wavelength has been formulated.
DOE↗
Ceramic Capacitor Grain Size Analysis Using Electron Backscatter Diffraction (EBSD)
The overall scope of this NESC study was to identify (or develop) a tool, methodology, or process that can inspect a ceramic capacitor and consistently return repeatable grain size distribution results. It is important to note that the development of a machine learning technique was considered as an option for this study, but only if an existing automated tool was not available. This report explains why the Electron Backscatter Diffraction analysis method for grain structure and size distribution was deemed a suitable candidate for this work.
Electron Backscatter Diffraction↗
X-ray diffraction technique
This is a guest lecture for University of Idaho graduate-level course Chemical and Materials Analysis. I will be talking about the fundamentals of X-ray Diffraction technique and some examples for its application in material science research.
36 MATERIALS SCIENCE↗
Uncovering a CF 3 Effect on X‐ray Absorption Energies of [Cu(CF 3 ) 4 ] − and Related Copper Compounds by Using Resonant Diffraction Anomalous Fine Structure (DAFS) Measurements**
Abstract Understanding the electronic structures of high‐valent metal complexes aids the advancement of metal‐catalyzed cross coupling methodologies. A prototypical complex with formally high valency is [Cu(CF 3 ) 4 ] − (1), which has a formal Cu(III) oxidation state but whose physical analysis has led some to a Cu(I) assignment in an inverted ligand field model. Recent examinations of1by X‐ray spectroscopies have led previous authors to contradictory conclusions, motivating the re‐examination of its X‐ray absorption profile here by a complementary method, resonant diffraction anomalous fine structure (DAFS). From analysis of DAFS measurements for a series of seven mononuclear Cu complexes including1, here it is shown that there is a systematic trifluoromethyl effect on X‐ray absorption that blue shifts the resonant Cu K‐edge energy by 2–3 eV per CF 3 , completely accounting for observed changes in DAFS profiles between formally Cu(III) complexes like1and formally Cu(I) complexes like (Ph 3 P) 3 CuCF 3 (3). Thus, in agreement with the inverted ligand field model, the data presented herein imply that1is best described as containing a Cu(I) ion with d n count approaching 10.
Chemistry↗