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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 93 for “"Metal cations"”.
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Separation of alkali metal cations and alkaline earth cations using ionizable crown ethers
… ethers are novel agents for the separation of metal ions by extraction and membrane transport processes. A series of novel crown ether carboxylic acids , crown ether phosphonic acid monoesters, and crown ether phosphonic acids which possess lipophilic pendant groups were employed for the study …
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Gas Phase Studies of Molecular Clusters Containing Metal Cations, and the Ion Mobility of Styrene Oligomers
… Part II the solvation of a variety of metal cations by benzene clusters have been studied using laser vaporization, cluster beam and time-of-flight mass spectrometry techniques. In this work strong magic numbers were observed for clusters containing 10, 13 and 14 benzene molecules …
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Carbon Monoxide Oxidation on Nanoparticle Catalysts and Gas Phase Reactions of Small Molecules and Volatile Organics with Metal Cations
… test indicates the formation of CuO within the bimetallic nanoparticles, whichimproves the catalytic activity of Au-Cu alloy nanoparticle.The second part of this dissertation investigates the gas phase reactions of Au+ and Cu+ with CO, O2 and H2O molecules using the Laser Vaporization ionization, …
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Noncovalent Interactions Between Alkali Metal Cation And Aza/thia-Crown Macrocycles: Mass Spectrometric Techniques And Theoretical Studies
… and thia-crown ether interactions with alkali metal cations. Infrared multiple photon dissociation (IRMPD) action spectroscopy and energy-resolved collision-induced dissociation (CID) techniques were used in conjunction with theoretical electronic structure calculations to characterize the …
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Synthesis and reactivity of early transition metal "Frustrated Lewis Pairs"
… thesis we demonstrate that Lewis acidic early metal cations can activate small molecules in the presence of sterically demanding donors to exhibit unique reactivity. The cationic Lewis acids [Cp2Zr(O't'Bu)] +, [Cp2Zr(OPh)]+, [Cp2Zr(OMes)] + and [Cp2Zr(ODipp)]+ are generated by the reaction …
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Synthesis and Characterization of Bis-Phosphine Complexes with Transition Metals
… processes, from the concentration of precious metals from ores to the separation of longlived nuclei from radioactive waste as well as the removal of heavy metals from soils and water for remediation. The vast majority of extractants rely on the use of nitrogen, oxygen, sulfur or selenium as …
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The effect of metal ion exchange and alkali metal doping on the electrical conductivity of the Faujasite-type zeolite 13X
… synthesized in the sodium form. Some transition metal cations were introduced into the zeolite framework by ion exchange reactions. These different cationic zeolite forms were doped or impregnated with sodium metal, utilizing the adsorptive properties of the zeolite. An A.C. technique was used to …
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Analysis of a model to describe lead transport by the small intestine
… and a concurrent slow passive diffusion of lead cations across the intestinal epithelium. The presence of methylxanthines, which diminish the size of the intercellular channels, were found to decrease the rate of lead cation transport, and indicated a paracellular route for lead transport. …
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Applications of functional nucleic acids in imaging, sensing and drug delivery and investigations of DNAzyme-metal interactions
… Enzymatic activity of most DNAzymes requires metal cations. The research on the metal-DNAzyme interaction is of interest and challenge to scientists because of the lack of structural information. Chapters 4 presents the research on the characterization of the interaction between a …
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Polyelectrolyte multilayers as nanostructured templates for inorganic synthesis
… carboxylic acid groups, were used to bind metal cations within the film. Metallic and semiconducting nanoparticles, including Ag, Pd, and ZnS, were formed in situ by reduction or sulfidation of the bound metal cations. The size and concentration of Ag nanoparticles were controlled by the …
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Adsorption of cobalt, chromium and barium on ripidolite and kaolinite as examined by x-ray photoelectron spectroscopy
… has been used to study the bonding of adsorbed metal cations to clay minerals. Binding energy differences of the adsorbed metal cations can be related to changes in the electron density or charge on the atom of interest. Adsorption experiments were carried out in aqueous solution at controlled …
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An investigation of cation-exchange in aqueous pyridine
… aqueous pyridine solutions of the alkaline earth metal cations. The ion-exchange phenomena investigated included: swelling, preferential sorption of solvent and selectivity variations with loading, degree of neutralization of the resin, solvent composition and choice of solution phase anion. The …
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G-wires: The growth and characterization of a G4-DNA nanostructure
… the presence of specific monovalent and divalent metal cations which are also required for maintaining the quadruplex stability. The structural basis of the quadruplex is a cyclic Hoogsteen hydrogen bonded guanine tetrad known as the G-quartet. Sequences capable of forming G-quartets are …
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Hydrogels containing linear and cyclic polyethers
… is observed for these systems with group II metal cations while the transport of group I metal cations, with the exception of sodium, is enhanced. Finally, the equilibrium water contents (EWC) surface and mechanical properties of these terpolymers containing linear polyethers were examined. …
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The Effect of the Secondary Coordination Sphere on the Stabilities of Cerium(III) and Cerium(IV) Coordination Complexes
… desirable components in many technological applications as well as useful catalysts. However, lanthanides can form unpredictable solid state and solution structures due to their ionic, non-directional, and kinetically labile bonds with ligands, which hampers the development of structure-function …
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Computational Studies on Nucleic Acid-Ion Interactions in Droplets and Bulk Solution
… pH of 7.4. Thus, DNA always associates with cations in the living cell. These cations are essential for maintaining DNA functions and structural stability. Experimental techniques showed that alkali metal cations are either diffused in the ionic atmosphere around the DNA duplex or are …
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The extraction of trichlorostannato-rhodium complexes by polyurethane foam
… Sn(II):Rh mol ratio and the presence of alkali metal cations. The extraction efficiency is promoted by increased acid concentration and high Sn(II):Rh ratios. The presence of K⁺ inhibits the extraction of rhodium, while the effect of Li⁺ and Na⁺ is small. A series of model urethane compounds …
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Design and Synthesis of Novel Cage-Functionalized Crown Ethers: A New Class of Ag Complexants.
… Ag+, which is a softer Lewis acid than alkali metal cations.
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Kesterite thin-film solar cell absorbers derived using inhomogeneous CZTS nanoparticles
… inhomogeneous nanoparticles supply the metal cations – namely Cu, Zn, and Sn – to the CZTSSe nuclei that grow at the top surface of the nanoparticle layer. These CZTSSe grains form a continuous thin-film and grow in size suggesting a liquid-assisted sintering mechanism in which molten Se …
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Microsolvatación de cationes en disolución. Desarrollo del modelo de ion hidratado intercambiable y su aplicación a la química de cationes radiactivos
… ] m+, are the most common structures adopted by metal cations, Mm+, when chemical conditions inhibit the formation of hydrolyzed and polymerized derivatives. 1 The implicit net charge, m+, and the polar and polarizable character of water lead to electrostatic effects so strong that the …
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