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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 27 for “"electric field gradient"”.
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Electric Field Gradient Focusing-UV Detection for Protein Analysis
<p>Electric field gradient focusing (EFGF) utilizes a hydrodynamic flow and an electric field gradient to focus and concentrate charged analytes and order them in a separation channel according to electrophoretic mobility. Elution can be achieved by decreasing the applied voltage or increasing the …
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Polymer Microchips for Capillary Electrophoresis and Electric Field Gradient Focusing of Biomolecules
… peak efficiencies of 43,000 theoretical plates. Electric field gradient focusing (EFGF), which uses a combination of pressure-driven flow and an electric field gradient to separate charged species according to their electrophoretic mobilities, was explored for protein analysis. Capillary-based …
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Crystal structure, electron density and chemical bonding in inorganic compounds studied by the Electric Field Gradient
… information about the electron density is the electric field gradient (EFG). The EFG reflects local structural symmetry properties of the charge distribution surrounding a nucleus: the EFG is nonzero if the density deviates from cubic symmetry and therefore generates an inhomogeneous electric …
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Applications of Nuclear Quadrupole Double Resonance Spectroscopy
… 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 state charge distribution in the vicinity of the …
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Electrochemically generating electric field gradients in the absence of buffer for membrane-free separations
… work described herein focuses on modulating the electric field within microelectrochemical devices for electrokinetic separations. Specifically, two new electrochemical approaches were investigated for forming electric field gradients which are useful for manipulating ion motion. The first method …
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A Study of Dilute Aluminum and Vanadium Nmr in Alpha-Titanium and in Hydrogen Doped Alpha-Titanium (Knight Shift, Electron Distribution, Quadrupole Interaction, Anisotropic, Alloy(hcp))
… simulation work, experimental parameters such as electric field gradient (EFG), axial anisotropic Knight shift K(,ax), and isotropic Knight shift are obtained. In addition to shedding light on certain features of bonding of V and Al in Ti, this information is used to discuss the trapping of …
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A nuclear magnetic resonance study of UNI₂AL₃
… technique. A value for the asymmetry of the electric field gradient has also been determined for this material. In addition, the temperature dependence of the Knight shift was observed over the range of 6 to 300K.No significant temperature dependence was found over this range.
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Nuclear magnetic resonance in single crystals of the dilute magnetic alloys: CuFe, CuCo, and CuNi
… these nuclei, called 63 satellites, occur at fields shifted from the much more intense Cumain resonance field when observed at a fixed frequency. Satellites were observed previously in these alloys in powdered samples only. The importance of these satellite resonances lies in the information …
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The Binding Pockets of QA and QB in the Photosynthetic Reaction Center of Rba. sphaeroides Probed by Pulsed EPR
… the quadrupole parameters are dependent on the electric field gradient at the nucleus of interest. Using these values, the two strongly coupled nitrogen nuclei were assigned to peptide and histidine for both quinone binding sites. The quadrupole asymmetry parameter was measureable only for the …
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Moessbauer Studies on Partially Oriented Samples of Carbon Monoxymyoglobin and Photodissociated Carbon Monoxymyoglobin
… result of the quadrupole interaction with the electric field gradient (EFG) at the ('57)Fe nucleus. The photo-produced partial orientation affects the intensity ratio R of the two lines; measurements of R versus the fraction MbCO remaining allows the determination of the asymmetry parameter …
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A Mossbauer study of divalent iron in silver chloride crystals
… ion gives rise to random fluctuations in the electric field gradient at the iron nucleus (quadrupole relaxation). Using a suitable model to describe the Mossbauer line shape in the presence of fluctuating hyperfine fields we have measured the activation energy for a vacancy jump and obtained, …
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Rotational spectra and molecular structures of organometallic and organic molecules
… structures, structural isomers and the electric field gradient distributions for these molecules.
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The Mossbauer effect of FE57 on the surface of tungsten
… splitting of the two surface lines indicate an electric field gradient at the surface of 2.4 x 10 16 V/cm 2 directed along the normal. An effective Debye temperature of 406 + l2°K is found for the bulk, from a study of the temperature dependence of the intensity of the M8ssbauer absorption. The …
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NMR, Crystallographic and Quantum Chemical Studies of Metalloproteins and Bisphosphonate Inhibitors
… 13C, 15N and 19F NMR hyperfine shifts, Mossbauer electric field gradient tensors (quadrupole splittings and asymmetry parameters) and their orientations, Mossbauer isomer shifts, and through space J-couplings. Excellent correlations between experiment and theory indicate that the computed …
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Mapping the magnetization density near magnetic atoms in copper: Nuclear magnetic resonance studies of CuMn and CuCr
… copper metal when observing at fixed magnetic field. Experiments are described on both powdered and single crystal alloy samples. The satellite signals are much stronger in powdered samples, but single crystals give more information. Powdered samples are used to find the satellites and measure …
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Investigation of Novel Microseparation Techniques
… is possible under certain operating conditions. Electric field gradient focusing (EFGF) devices with distributed resistor substrates could focus proteins in the separation channel, however, the focused bands were not stable, and the repeatability was poor due to the formation of bubbles and pH …
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Fabrication of Polymeric Microfluidic Devices for Protein Analysis
… buffer ion permeable membrane in a PGMAMMA micro electric field gradient focusing (µEFGF) device. Using the µEFGF device, green fluorescent protein (GFP) was concentrated 4000-fold. Separation of GFP and R-phycoerythrin (R-PE), and selective elution of GFP from a protein mixture containing GFP, …
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Microbial instrumentation utilizing microfluidics
… the microchannel geometry which applies a linear electric field gradient to each sample. This design enables rapid determination of the electric field that leads to quantifiable bacterial electroporation. Bacterial strains with both industrial and medical relevance have been successfully …
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Advances in oxygen-17 NMR for biological structure determination
… spectroscopy has materialized as an important field due to the high-resolution details that the technique provides. While solid-state NMR studies have focused on the three prevalent spin I = 1/2 nuclei present in biomolecules, oxygen has largely been ignored as a probe of the structure of such …
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Detection of Proteins by Two-Photon Excitation of Native Fluorescence
… µTAS separation methods, the relatively new electric field gradient focusing (EFGF) technique has shown potential. It focuses and separates analytes based on their electrophoretic migration in an opposing hydrodynamic flow. The detection principles that are compatible with µTAS separation may …
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