Global ETD Search
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 19 of 19 for “"Spin-Spin-Relaxation"”.
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The effects of polymer-controlled hydration on nuclear magnetic resonance parameters
… phase transition temperature (Tn,), the spin-lattice relaxation times and the spin-spin relaxation times were investigated as the membrane was dehydrated. Both Avg and Tn, are hydration dependent but no systematic change in the relaxation times was noted as a function of the water content …
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The development and applications of Fourier transformed relaxation measurements in nuclear magnetic resonance (NMR)
A method has been developed to measure the spin-lattice and spin-spin relaxation times of the various components of a multi-component spectrum. By Fourier transforming the free induction decay after the inversion recovery or spin echo pulse sequences, the different frequency components can be …
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Low-field classroom nuclear magnetic resonance system
… ability to observe Nuclear Magnetic Resonance. 'Spin- Lattice' and 'Spin-Spin' relaxation times of glycerin samples can easily be measured. Future work will allow further MRI exploration by incorporating gradient magnetic field coils.
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Nuclear magnetic resonance studies of the organic superconductor kappa-(bisethylenedithiotetrathiafulvalene)(2) copper(nitrogen(cyanide)(2))bromine
… field dependent lineshapes, Knight shifts, spin-spin relaxation rates and spin-lattice relaxation rates for the $\sp{-1}$H and $\sp{13}$C sites located in the organic ET molecules of $\kappa$-(ET)$\sb2$CU (N(CN)$\sb2$) Br for temperatures 2 K $$ 4.3 T). We studied the orientation dependence …
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Proton magnetic resonance of wood and water in wood
… a technique for analysing multi-exponential relaxation in terms of a continuous distribution of relaxation times was applied to T2 analysis of lumen water in wood. The lumen water T2 times vary as a function of the wood cell radius and are therefore expected to reflect the cell size …
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Crosslinking and Entanglement Effects in Polybutadiene
Proton relaxation measurements have been used to investigate the effects of crosslinking and entanglements on segmental motion in polybutadiene. The temperature dependence of T(,1), the spin-lattice relaxation time, T(,2), the spin-spin relaxation time, and T(,1(,(rho))), the spin-lattice …
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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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High-pressure NMR studies of model membranes and Kramers turnover on solution
… and anesthetic effects on lineshapes and various relaxation times of phospholipid model membranes DPPC in multilamellar dispersions and in unilamellar vesicles have been investigated by using $\sp{31}$P NMR, $\sp2$H NMR, as well as one and two dimensional $\sp1$H NMR techniques in both the liquid …
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Synthesis and evaluation of polyol based biolubricants from vegetable oils
… was determined between 298 K and 238 K using T2 relaxation. The results showed that the singlet attributed to TMP protons broadened until it disappeared as temperature decreased. The results indicated that the log of the spin-spin relaxation time is linearly correlated with rising temperature.
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Carbon-13 NMR Relaxation Study of Motional Dynamics in Complex Liquids
… has been investigated using $\sp{13}$C NMR relaxation measurements. Natural abundance $\sp{13}$C NMR spin-lattice relaxation times (T$\sb1),$ spin-spin relaxation times (T$\sb2),$ and nuclear Overhauser effects of individual carbon nuclei in the complex phthalate liquids were measured as a …
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Signal sampling and processing in magnetic resonance applications
… developed for Nuclear Magnetic Resonance (NMR) relaxation and diffusion experiments. $L_1$ regularization is recommended for extracting parameter distributions which are a priori known to be composed of sparse features. $L_1$ regularization is shown to be stable at signal-to-noise ratios < 20 …
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13C-nuclear-magnetic-resonance of carbon monoxide on platinum: Study of a highly dispersed catalyst
The 13C Nuclear Magnetic Resonance lines, spin-lattice relaxation times Tl and spin-spin relaxation times T2 of CO chemisorbed on the surface layer of small particles of Pt metal have been observed by the method of spin echoes as a function of magnetic field, temperature, CO coverage and Pt …
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Nuclear magnetic resonance spectroscopy and ultrasound
… detected by nuclear magnetic resonance (NMR) in spin-lattice and spin-spin relaxation times. The objective being to develop a method capable of reducing the pulsed NMR acquisition times of slowly relaxing nuclei. The thesis describes the theoretical principles underlying both NMR spectroscopy and …
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Carbon-13 - Nuclear - Magnetic - Resonance of Carbon Monoxide on Platinum: Study of a Highly Dispersed Catalyst (Nmr)
The ('13)C Nuclear Magnetic Resonance lines, spin-lattice relaxation times T(,1) and spin-spin relaxation times T(,2) of CO chemisorbed on the surface layer of small particles of Pt metal have been observed by the method of spin echoes as a function of magnetic field, temperature, CO coverage and …
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Hochfeld 1H-NMR-Mikroskopie zur biophysikalischen Grundlagenforschung
Dank der mit modernen NMR-Spektrometern (Kernspintomographen) routinemäßig realisierbaren isotropen räumlichen Auflösungen von wenigen Mikrometern, ergeben sich für die 1H NMR-Mikroskopie zahlreiche neue Anwendungsgebiete. Allerdings sind die Möglichkeiten und Grenzen der NMR-Mikroskopie bezüglich …
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State-of-the-art REDOR and TEDOR methods for elucidation of protein structure and interactions
… structure and their interactions is magic angle spinning (MAS) SSNMR spectroscopy due to its ability to examine insoluble systems and with no inherent restriction on the size of the molecule. For structure determination and refinement, we employ famous and robust techniques like rotational echo …
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Study of relaxation processes in simple glass formers by means of 2H NMR spectroscopy
… echo and 2D spectra, stimulated echo decays, spin-lattice and spin-spin relaxation). We focused our attention on glass forming liquids that were composed of simple, rigid molecules in order to study the properties of the secondary relaxation processes (beta-processes) in the glassy state …
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Nuclear magnetic resonance as a tool for on-line catalytic reaction monitoring
… in water and hydrogen peroxide on the transverse relaxation rate, together with pH, to obtain a quantification of the H2O2 concentration during the reaction, in the liquid surrounding the catalyst; the use of the chemical exchange as a source of contrast in NMR Imaging, providing a tool for …