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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 14 of 14 for “"NQR"”.
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Magnetic resonance imaging via radio frequency gradient with examples from NMR and pure NQR
… and frequency variations). In the case of pure NQR imaging, RF gradients preserve an undistorted line-shape. RF gradients also present significant new challenges in both the probe design and the spin dynamics. All of these issues are addressed in this thesis. Potential applications of RF …
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Array Analysis of Radio Frequency Interference Cancelation Requirements for a Land Mine Detection System
… are needed. Nuclear Quadrupole Resonance (NQR) is one such technique. Unfortunately, NQR is highly succeptible to radio frequency interference (RFI). A significant contribution of this thesis is the development of a custom, experimental data acquisition system designed and built …
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Applications of Nuclear Quadrupole Double Resonance Spectroscopy
Nuclear quadrupole double resonance (NQR) spectroscopy can yield direct information about the nature of chemical bonding at a particular quadrupolar nucleus (S (GREATERTHEQ) 1) in a molecular crystal. However, due to experimental difficulties related to the low transition frequencies generally …
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Nitrogen-14 Nuclear Quadrupole Resonance Studies of Pyrimidine and Purine Derivatives
… descriptions of nuclear quadrupole resonance (nqr) are reviewed. Fundamental principles of nuclear spin thermodynamics are introduced to explain double resonance via level crossing (drlc), the experimental technique employed to detect ('14)N nqr resonances.
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Instrumentation for quantum computers
… using a customized nuclear quadrupole resonance (NQR) spectrom- eter, which incorporates both devices. The two devices control the generation of RF pulses used in NQR experiments on paradichlorobenzene (C₆H₄C₁₂) and sodium nitrite (NaNO₂). The NQR signals originating from ¹⁴N in sodium nitrite and …
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Applications of Nuclear Quadrupole Double Resonance Spectroscopy
Nuclear Quadrupole Resonance (NQR) spectroscopy measures the interaction of a nucleus possessing an electric quadrupole moment Q with the electric field gradient (efg) produced at the nucleus by its local electronic environment. As a result, the NQR technique provides information on the ground …
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Nuclear Quadrupole Double Resonance Spectroscopy: Studies of Hydrogen Bonding and Metal-Nitrogen Interactions
… interest in nuclear quadrupole resonance (NQR) spectroscopy. This attention stems from the advent of double resonance methods capable of observing with high sensitivity the weak quadrupole resonances. Through double resonance NQR much new and useful information regarding the solid state …
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Zero field NMR study on a spin glass: Iron-doped 2H-niobium diselenide
We have used spin echoes to study the 93Nb NQR in 2H-NbSe2Fex. We measured (intensity)x(temperature), and T1P (spin-lattice relaxation parameter) and T2 (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x=O, 0.25%, 1% and …
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Zero Field Nmr Study on a Spin Glass: Iron-Doped 2hydrogen-Niobium Diselenide
We have used spin echoes to study the ('93)Nb NQR in 2H-NbSe(,2)Fe(,x). We measured (intensity) x (temperature), and T(,1P) (spin-lattice relaxation parameter) and T(,2) (spin-spin relaxation time) as a function of temperature. Our data reveal dramatic difference between non-spin glass samples (x = …
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Deuterium and Nitrogen-14 Nuclear Quadrupole Double Resonance Studies of Hydrogen Bonding
… and nitrogen-14 nuclear quadrupole resonance (nqr) spectroscopy. The experimental techniques of double resonance with level crossing and double resonance with continuous coupling were employed to detect quadrupolar transitions.
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Biochemical Studies of the Sodium -Translocating NADH:ubiquinone Oxidoreductase
In the NqrF subunit, four conserved cysteines (C70, C76, C79 and C111) are predicted to ligate the 2Fe-2S center, and three conserved residues (R210, Y212, S245) are predicted to be essential to the binding of the FAD cofactor. By mutagenesis and spectroscopic characterization, the four conserved …
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Synthesis and magnetic properties of novel Ln[subscript 2-x]MxCuO[subscript 4+y] compositions (Ln = La,Pr,Nd,Sm,Eu,Gd; M = Ca,Sr,Ba; 0<=x<=0.2; -0.5<=y<=0.5)
… physical properties. [superscript]139La NQR measurements of nonsuperconducting La[subscript]1.85Sr[subscript]0.15CuO[subscript]4.04 show metallic properties. The tolerance factor, which is based on ionic radii, is quite successful to describe structural properties of …
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Roles for multiple iron acquisition systems in Vibrio cholerae
… Deletion of the major NADH dehydrogenase, Na+-NQR alters the kinetics of iron reduction; as such, we propose a model whereby VciB mediates reduction of iron by re-directing electrons from the electron transport chain. VciB supports Fe2+ transport through the Feo system, as strains dependent on …