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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 20 of 36 for “"molecular motion"”.
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Thermal Diffusion and Molecular Motion
Made available in DSpace on 2014-12-05T17:15:20Z (GMT). No. of bitstreams: 1 0016432.pdf: 4785373 bytes, checksum: c0fb0c712068ee40dfcaef4678045df2 (MD5) Previous issue date: 1956
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Nuclear magnetic resonance studies of highly compressed fluids
… to investigate the translational and rotational motions of molecules in supercritical fluid and model lubricant systems. NMR has also been used to study molecular conformations and cross relaxation in the model lubricant 2-ethylhexyl benzoate. In each of the studies, the ability to use pressure …
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Flow and static ¹H, ¹⁹F and ¹⁴N NMR studies in dense fluids
… LC/¹H NMR approach. The relaxation behavior and molecular motion of dilute solutions of benzene and acetonitrile in sub- and supercritical CO₂ were determined using stopped flow ¹H and ¹⁴N NM. The nuclear spin-lattice relaxation times (T₁) for ¹H and ¹⁴N were measured through inversion recovery …
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Applications of high resolution solid state carbon-13 NMR to the study of multicomponent polymer systems
… are: (1) the nature of domain structure and molecular motion of two thermoplastic elastomer systems, including a series of styrene isoprene-styrene linear triblock copolymers (SIS’s) of various compositions, molecular weights and sample histories, and a poly(ester)- urethane based on …
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High Pressure Light Scattering Studies of Dense Fluids (Collision, Induced, Lineshape)
… tool for probing the density dependence of both molecular motion and intermolecular interactions. This thesis describes high pressure light scattering studies of the vibrational relaxation of the nitrate ion in aqueous solutions of sodium nitrate and of collision induced light scattering in …
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Study of relaxation processes in simple glass formers by means of 2H NMR spectroscopy
In the present work molecular glass formers were investigated by means of multidimensional 2H NMR (solid 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 …
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Evaluation of the sonically induced narrowing of nuclear magnetic resonance spectra of solids
… information depends on the incoherent rapid molecular motion that causes complicating effects present in the solid state to average to zero. Whereas liquid state NMR spectra show narrow lines, the corresponding NMR spectra from the solid state are normally composed of exceedingly broad …
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Synthesis, properties, and modifications of engineering polymers
… were synthesized in order to investigate molecular motion via deuterium NMR. The mechanical, dynamic mechanical and fracture properties of these materials were also examined. Polysulfones were characterized to be tough, ductile materials and it was found that …
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Nanofluidic Channels for Biological Separations
… devices offer the possibility of modeling molecular motion through confining environments from fundamental physical principles. Three nanofluidic devices for separating biomolecules by length are discussed herein. A description of their physical operation is given, and results indicating …
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Visualizing models driven by real-time, sensor-based data : a new way to experience the inner workings of ecosystems
… is the first of its kind to visualize models of molecular motion and carbon flow in 3D, within the context of the physical site, and driven by realtime data. Whether experienced remotely or integrated on site, EcoFlux can be used to inspire curiosity for visitors, enhance scientific understanding …
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In-situ 13C CM-MAS NMR study of dilute acid biomass pretreatment on 13C enriched poplar wood
… on the effect of pretreatment on local molecular mobilities. In addition, spin-lattice relaxation values for 13C and for 1H, as well as cross polarization time constants TCH-1 and T1pH-1, were measured on dry wood, and on wood 10 % in 0.5 M sulfuric acid before, during and after …
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Flow 1H Dynamic Nuclear Polarization Studies in Normal Liquids and Supercritical Fluid Carbon Dioxide
… SF CO₂ resulted in a 2-6 factor increase in the molecular motion of the molecule in the SF--the result of which corresponds to the expected factor increase in DNP signal enhancements in the low viscosity fluid. Observed DNP signal enhancements were 2-5 times greater in the supercritical fluid …
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An Original Method for Computing Complex Non-Premixed Flows in Chemical Equilibrium
… for the atomic densities rather than for the molecular species densities, as is the case for non-equilibrium flow calculations. The method is suited for applications to mixing flows in rocket engine combustors, where, due to the typical low convective speed, chemical reaction is best modeled …
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Carbon-13 NMR Relaxation Study of Motional Dynamics in Complex Liquids
The motional behavior of complex liquids of various phthalates and structurally related compounds 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 …
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Electrical properties of polyimides modified with metal salts
… useful for probing polymer contamination and molecular motion. Further, the electrical measurements indicated that uniformity between samples was poor. Modification of an inert gas oven, allowing processing in controlled atmosphere, proved that film surface conductivity is critically …
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New Rotaxane Ligands with Donors on Both the Axle and Wheel
… of interpenetrated and interlocked molecules, molecular motion, metal-ligand interactions and metal organic rotaxane frameworks (MORFs). Chapter 2 explores the preliminary studies of the coordination ability of a model compound containing a xylene backbone with two sulphur donor atoms to a …
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Proteins on the edge : transitions of structure ensembles in protein unfolding and protein-protein binding
… diverse ensemble of interchanging conformations. Molecular motion is often the barely understood link between structure and biological function. The present work examines two different processes that put proteins on the edge of moving from one global state to another. At the moment of transition, …
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NOVEL ETHYLENE-BRIDGED HEXADENTATE BIS(AMIDINES), BIS(AMIDINATES), AND MULTINUCLEAR COINAGE METAL BIS(AMIDINE) COMPLEXES
… insertion of the M–Cl fragments into the intramolecular NH···N' hydrogen bonds of <strong>L</strong><sup>4</sup>H<sub>2</sub>. These hydrogen bonds can be observed in the solid state and <sup>1</sup>H NMR spectroscopy. Accompanying low-temperature VT-NMR studies of <strong>1</strong> and …
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Towards Glasses from Two-Dimensional Hybrid Organic–Inorganic Perovskites
… over various length scales, while dynamic molecular motion during melting and vitrification is probed. These insights are further correlated with the mechanical and optical responses of the glass, enabling the establishment of key structure-property relationships. Chapter 6 extends the …
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Studies of hydrogen bonding in protonic ionic liquids and their binary mixtures
… systems, such as temperature, composition and molecular weight, in a collaboration with a research group from Complutense University of Madrid.<br/><br/>All these ionic liquids: ethylammonium nitrate, propylammonium nitrate, butylammonium nitrate, diethylammonium nitrate, triethylammonium …
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