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in subjects: "Nuclear Techniques In Condensed Matter Physics"  
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Photoelectron diffraction and holography: Present status and future prospects

Description: Photoelectron diffraction and photoelectron holography, a newly developed variant of it, can provide a rich range of information concerning surface structure. These methods are sensitive to atomic type, chemical state, and spin state. The theoretical prediction of diffraction patterns is also well developed at both the single scattering and multiple scattering levels, and quantitative fits of experiment to theory can lead to structures with accuracies in the {plus_minus}0.03 {Angstrom} range. D… more
Date: July 1, 1993
Creator: Fadley, C. S.; Thevuthasan, S. & Kaduwela, A. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Microcontamination detection using Heavy Ion Backscattering Spectrometry

Description: Heavy Ion Backscattering Spectrometry (HIBS) is a new ion beam analysis tool using heavy, low-energy ions in backscattering mode which can detect very low levels of surface contamination. By taking advantage of the greatly increased scattering cross-section for such ion beams and eliminating unwanted substrate scattering with a thin carbon foil, our research system has achieved a sensitivity ranging from {approximately}5{times}10{sup 10} atoms/cm{sup 2} for Fe to {approximately}1{times}10{sup 9… more
Date: July 1, 1994
Creator: Knapp, J. A.; Banks, J. C. & Diebold, A. C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Magnetic X-Ray Circular Dichroism in Spin-Polarized Photoelectron Diffraction

Description: The first structural determination with spin-polarized, energy-dependent photoelectron diffraction using circularly-polarized x-rays is reported for Fe films on Cu(001). Circularly-polarized x-rays produced spin-polarized photoelectrons from the Fe 2p doublet, and intensity asymmetries in the 2p{sub 3/2} level are observed. Fully spin-specific multiple scattering calculations reproduced the experimentally-determined energy and angular dependences. A new analytical procedure which focuses upon i… more
Date: July 12, 1994
Creator: Waddill, G. D.; Tobin, J. G.; Guo, X. & Tong, S. Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Low-frequency nuclear quadrupole resonance with a dc SQUID

Description: Conventional pure nuclear quadrupole resonance (NQR) is a technique well suited for the study of very large quadrupolar interactions. Numerous nuclear magnetic resonance (NMR) techniques have been developed for the study of smaller quadrupolar interactions. However, there are many nuclei which have quadrupolar interactions of intermediate strength. Quadrupolar interactions in this region have traditionally been difficult or unfeasible to detect. This work describes the development and applicati… more
Date: July 1, 1991
Creator: Chang, J. W.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Phase transitions and neutron scattering

Description: A review is given of recent advances in neutron scattering studies of solid state physics. The author has selected the study of a structural phase transition as the best example to demonstrate the power of neutron scattering techniques. Since energy analysis is relatively easy, the dynamical aspects of a transition can be elucidated by the neutron probe. He will discuss in some detail current experiments on the 100K transition in SrTiO{sub 3}, the crystal which has been the paradigm of neutron … more
Date: July 1, 1993
Creator: Shirane, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Neutron-induced collision cascade mixing in Nb/V superlattices

Description: High-angle X-ray diffraction was used to determine cascade mixing efficiencies, Dt/dpa, in Nb/V superlattices irradiated to small doses ({le}0.26 dpa). Samples were neutron irradiated in the core of the High Flux Beam Reactor at Brookhaven National Laboratory and ion irradiated with 1.5 MeV Ne. No significant differences were observed in cascade mixing efficiencies between the two types of irradiation. Values of Dt/dpa were observed to vary with the modulation wavelength of the superlattice, wi… more
Date: July 1, 1993
Creator: Alexander, D. E.; Fullerton, E. E.; Baldo, P. M.; Sowers, C. H. & Rehn, L. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Two dimensional NMR and NMR relaxation studies of coal structure. Progress report, January 1, 1992--March 31, 1992

Description: This report covers the progress made on the title project for the project period. Four major areas of inquiry are being pursued. Advanced solid state NMR methods are being developed to assay the distribution of the various important functional groups that determine the reactivity of coals. Special attention is being paid to methods that are compatible with the very high magic angle sample spinning rates needed for operation at the high magnetic field strengths available today. Polarization inve… more
Date: July 1, 1992
Creator: Zilm, K. W.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Positron implantation profiles in elemental and multilayer systems

Description: Different Monte Carlo schemes for modeling positron and electron implantation in solids have been briefly reviewed. Results (mean depth, backscattered fraction, profile shapes) of the Monte Carlo schemes are compared with experimental data and each other. Qualitatively, results of the different Monte Carlo schemes are the same; the most significant difference is in the value of the mean implantation depth. The scaled profiles (for positron implantation in any material) generated by the differen… more
Date: July 1, 1994
Creator: Ghosh, V. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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NQR-NMR studies of higher alcohol synthesis Cu-Co catalysts. Quarterly technical progress report, March 15--June 15, 1991

Description: The primary objective of the project is to examine the relations between the catalytic and magnetic properties of the copper-cobalt higher alcohol synthesis catalysts. We have undertaken to investigate the magnetic character by studying the Nuclear Quadrupole resonance of copper and (Zerofield) Nuclear Magnetic Resonance of cobalt in copper cobalt catalysts.
Date: July 15, 1991
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Methyl quantum tunneling and nitrogen-14 NQR NMR studies using a SQUID magnetic resonance spectrometer

Description: Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) techniques have been very successful in obtaining molecular conformation and dynamics information. Unfortunately, standard NMR and NQR spectrometers are unable to adequately detect resonances below a few megahertz due to the frequency dependent sensitivity of their Faraday coil detectors. For this reason a new spectrometer with a dc SQUID (Superconducting Quantum Interference Device) detector, which has no such frequency de… more
Date: July 1, 1993
Creator: Black, B. E.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Double rotation NMR studies of zeolites and aluminophosphate molecular sieves

Description: Goal is to study the organization and structures of guest atoms and molecules and their reactions on internal surfaces within pores of zeolites and aluminophosphate molecular sieves. {sup 27}Al and {sup 23}Na double rotation NMR (DOR) is used since it removes the anisotropic broadening in NMR spectra of quadrupolar nuclei, thus increasing resolution. This work concentrates on probing aluminum framework atoms in aluminophosphate molecular sieves and sodium extra framework cations in porous alumi… more
Date: July 1, 1993
Creator: Jelinek, R.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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PIXEF: The Livermore PIXE spectrum analysis package

Description: PIXEF (for, PIXE-Fit) is a proton-induced x-ray emission (PIXE) data analysis program designed for analyzing medium to heavy element matrices while retaining the capability to treat lower atomic number targets. Using nonlinear least squares fitting techniques, algorithms have been developed or modified both for fitting the characteristic x-ray peaks and representing the associated bremsstrahung and {gamma}-ray background. Self-absorption and secondary fluorescence are explicitly determined for … more
Date: July 1, 1993
Creator: Antolak, A. J. & Bench, G. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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{sup 199}Hg and {sup 63,65}Cu NMR studies of mercury based high-Tc superconductors

Description: Hg-oxide ceramic high temperature superconductors were studied with {sup 199}Hg- and {sup 63,65}Cu- NMR spectroscopy. Room temperature spectra, spin-spin and spin-lattice relaxation times of samples with different superconducting transition temperatures are presented. A spin-lattice relaxation time of T{sub 1} = 35 msec and a spin-spin relaxation time of T{sub 2} = 1.6 msec is found for the 199 Hg-NMR. All samples exhibit similar characteristic powder spectra caused by an axially symmetric {sup… more
Date: July 1, 1994
Creator: Hoffmann, W.; Breitzke, H.; Simmons, C. T.; Lueders, K.; Buntkowsky, G.; Limbach, H. H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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