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Showing 1 to 17 of 17 for “"Paramagnetic species"”.
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Characterization of catalyst pellets using NMR and MRI: MRI, diffusion and relaxation measurements of liquid imbibed in alumina and titania extrudates
… materials containing high concentrations of paramagnetic species. PFG NMR measurements are usually carried out at high magnetic field strengths (>1 T) but this is not possible when samples contain high concentrations of paramagnetic species as the NMR signal lifetime becomes very short. Short …
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Nanodiamonds for biological applications: Synthesis by laser ablation and sensing of local magnetic environment by optical spectroscopy of NV centers
… of commercial fluorescent NDs as probes of paramagnetic species. In the first part of my thesis, I report a novel synthesis route for NDs by pulsed laser ablation (PLA) in water. PLA can directly produce diamonds on a nanoscopic scale, with potential advantages over alternative methods, like …
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High-frequency time domain electron paramagnetic resonance : methods and applications
… to high frequency (high field) electron paramagnetic resonance (EPR) spectroscopy. Two of the most important are improved sensitivity and the improved resolution of field dependent interactions. In addition, there are many attractive features to time domain spectroscopy. Pulsed EPR allows …
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Electron paramagnetic resonance analysis of dimethyl amidogen in polycrystalline tetramethyl tetrazene.
… of tetramethyl-2-tetrazene yields a short-lived paramagnetic species which is stabilized at liquid nitrogen temperatures. For the analysis of the electron paramagnetic resonance spectrum the species has been identified as the free radical dimethyl amidogen. The hyperfine coupling tensors were …
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Synthetic and mechanistic investigation of new radical processes: reaction of organic azides with group-XIII Lewis acids
… gives rise to strongly coloured, persistent paramagnetic species, whose structure is consistent with the radical cation of the head-to-tail dimer of the aniline corresponding to the starting azide.
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Magnetic resonance investigations of pH in microemulsions
… achieved using the pH-dependent chelation of the paramagnetic species Cu(II), with the chelating ligand triethylenetetramine. However, it was found that MR contrast agents were not required for probing the pH in reverse micelles of the CTAB and Triton-X microemulsions. Magnetic resonance imaging …
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Chromatography and purification of endohedral metallofullerenes
… Predicted applications for these novel species include their use as possible superconductors, catalysts, and non-linear optical devices. However, initial purification efforts have been hindered by several difficulties. These factors include a low abundance (< 1%) in the raw extract, …
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Dinitroxides in Rapid Scan Electron Paramagnetic Resonance Imaging
… disease behavior. Rapid Scan (RS) electron paramagnetic resonance (EPR) offers a unique, non-invasive tool for investigation of these so-called microenvironments through EPR Imaging (EPRI). Research into advancement of EPRI falls into many categories. Not least among those are advances in …
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Understanding Transition Metal Dissolution from Battery Materials with Solution NMR Methods
… transition metals (e.g., Mn²⁺, Ni²⁺, Co²⁺) are paramagnetic. In NMR measurements, paramagnetic solutes can significantly affect the peak positions and relaxation rates of nearby chemical species in solution. This work therefore explores the use of solution NMR to characterise and quantify …
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First-principles study of radiation-induced radicals in solid-state amino acids and sugars: confrontation of density-functional calculations with experimental results
… induced as the result of radiation damage. Such species are normally very shortliving in gas phase or solution. In crystals on the other hand, the radicals become “trapped” inside the amino-acid or carbohydrate lattice and their reactivity will be sharply reduced. The solid state therefore offers …
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A Lewis Acidic Stroll Through the p-Block
… cations act as one-electron acceptors to form paramagnetic species, and a combination of the bulky phosphine PtBu3 and one of the azophosphonium cations acted as an FLP to effect the cleavage of disulfides. Phosphorus(V) dications containing both an ortho-quinone and terpyridine backbone were …
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Development of Low Frequency Electron Paramagnetic Resonance Methods and Instrumentation for Biological Applications
… field gradients, the spectral properties of paramagnetic species can be mapped. To facilitate EPR imaging, methods and instrumentation at frequencies between 250 MHz and 1 GHz were developed.</p> <p>At low spin concentrations, the rapid scan background signal is often many times larger than …
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Fundamental studies of heap leaching hydrology using magnetic resonance imaging
… heap leaching systems. The ferro- and paramagnetic species in the ore were found to cause significant distortions in frequency encoded MRI acquisitions. These distortions were mitigated through the application of single point imaging techniques. Comparison with equivalent X-ray CT …
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Qo site of the bc1 complex; unlocking the gate of the electron transport chain
… oxidation/reduction states by ob-serving the paramagnetic species by EPR. Spectral analysis using CW and pulsed EPR shows a SQo species not previously characterized, and has allowed resolution of some interesting struc-tural details. These suggest a species with spin coupling both to …
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Synthetic investigations of molybdenum pyrrolide and related complexes
… of silanols to Mo(NR)(CHCMe 2Ph)(pyrrolyl) 2 species (R = 1 -adamantyl (Ad) or 2,6-i-Pr2C6H3 (Ar)). The silanols employed include (t-Bu)3SiOH (Hsilox), (i-Pr)3SiOH, (Me3Si)3SiOH, (t-Bu-0)3SiOH, Me2(t-Bu)SiOH, and Ph 3SiOH. The mono(silox) complex, Mo(NAr)(CHCMe 2Ph)(silox)(pyrrolyl) .(2a), …