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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 15 of 15 for “"Bragg Diffraction"”.
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Real-Time Image Processing Using Acousto-Optic Bragg Diffraction
… have been limited to two diffracted order in the Bragg regime and two spatial dimensions. Some comparisons between experimental data and theoretical predictions have been made. This dissertation studies image processing by acousto-optic Bragg diffraction to perform image enhanment. Theoretical …
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Synthesis and Characterization of Functional Mesostructures Using Colloidal Crystal Templating
… allow tuning of properties such as Bragg diffraction, potentially enabling applications as electrochemical elements, sensors, flow control devices, and novel photonic band gap materials. Inverse opal conducting polymer films were fabricated by electropolymerization. The templated …
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Diffuse X-ray scattering from tropomyosin crystals
… important. All motions in the crystal affect the Bragg scattering and also give rise to diffuse scattering between and surrounding the Bragg spots. The diffuse X-ray scattering may comprise a large part of the total scattering from the crystal, and it contains information about the correlation of …
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Synthesis and characterization of crystalline assembly of poly Nisopropylacry-lamide)-co-acrylic acid nanoparticles.
… different observation angles, indicating typical Bragg diffraction. Shear moduli of the gel nanoparticle crystals were measured in the linear stress-yield ranges for the same gel crystals in both acetone and water. Syntheses of particles of different sizes and the relationship between particle …
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Design and fabrication of sharp bend photonic crystal slab waveguides
… presents a periodic potential for electrons. The bragg diffraction of electrons from the atoms may lead to a band gap, which represents a range of frequencies the electrons cannot have in the crystal. An analogous effect takes place in photonic crystals, which are periodic arrangement of layers of …
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Negative Thermal Expansion in Zincblende Structure: an EXAFS study of CdTe
… analysis. A critical comparison of EXAFS and Bragg diffraction results; thermal expansion, thermal factors and correlation of atomic vibration, for the iso-structural crystals Ge, CdTe and CuCl has been performed. The correlation between several quantities measured by EXAFS and NTE properties …
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Effects of interaction in Bose-Einstein condensates
… phonon wavefunction in a BEC was measured using Bragg spectroscopy and compared with the well-known Bogoliubov theory. Phonons were first excited in a BEC of 3 x 107 condensed 23Na atoms via small-angle two-photon Bragg scattering. Large angle Bragg scattering was then used to probe the momentum …
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Novel ground states of Bose-condensed gases
… particular, we have extended Kapitza-Dirac and Bragg diffraction to cold molecules. By measuring the Bragg spectrum of the molecules immediately after their creation, the conversion from atoms to molecules was shown to be coherent - the matter wave analog to frequency doubling in optics. In …
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Studies of the electrical properties and electroforming of thin insulating films
… and 300 K. It was shown that electrons underwent Bragg diffraction through the top Au electrode. The angular distribution of emitted electrons became more isotropic with increasing voltage. Measurements on other systems showed that Al-SiOx/B2O3-Al devices could withstand very high voltages and …
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Sviluppo di un tomografo multi-energy per lo studio pre-clinico di nuove metodiche diagnostiche finalizzate al riconoscimento precoce della patologia tumorale
… 26 KeV to 72 KeV. These beams are produced by Bragg diffraction on a Highly Oriented Pyrolytic Graphite crystal. With quasi-monochromatic sources it is possible to perform multi-energy investigation in a more effective way, as compared with conventional X-ray tubes. Multi-energy techniques …
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Volume holographic pupils in ray, wave, statistical optics, and Wigner space
… efficient computation method of analyzing volume diffraction is developed. It is integrated with the ray tracing software ZEMAXr whose built-in analysis and optimization features provide a great versatility for analysis, design, and optimization of novel volume holographic imaging systems. For a …
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X-RAY CHARACTERIZATION OF PLATINUM GROUP METAL CATALYSTS
… establishing the structure/property link. X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS) are important techniques used for the characterization of PGM catalysts. Microstructural information such as crystallite size, as small as ~ 1 nm, and microstrain can be obtained from Bragg …
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Holographic Point-of-Care Diagnostic Devices
… The fabricated sensors consisted of off-axis Bragg diffraction gratings of ordered silver nanoparticles and localised refractive index changes in poly(2-hydroxyethyl methacrylate) and polyacrylamide films. The sensors exhibited reversible Bragg peak shifts, and diffracted the spectrum of …
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Quantitative analysis of crystal lattice and defects in nanoscale functional materials by electron diffraction
… technique in TEM, called scanning electron nanodiffraction (SEND) or four-dimensional (4D) scanning transmission electron microscopy (STEM) or 4D-STEM, is emerging as a powerful way to provide information in both real space and reciprocal space at the same time based on electron nanodiffraction. …
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Momentum-space lattices for ultracold atoms
… of the condensate atoms through a two-photon Bragg diffraction process. Neighboring states in the free-particle dispersion relation are characterized by a unique momenta and energy spacing such that we can independently control every aspect of their coupling. In this thesis, we report on the …