No description available.

The synthesis of the sodium salt of heptakis (2, 3-di-O-acetyl-6-O-sulfo)-β-cyclodextrin was modified to increase the isomeric purity to 98.5%. This salt was used to obtain the organic-solvent-soluble, single-isomer, charged tetrabutylammonium salt of heptakis (2, 3-di-O-acetyl-6-O-sulfo)-β-cyclodextrin. Its isomeric purity was higher than 99%, as determined by CE, and its structure was confirmed by NMR and ESI-MS analysis. The hydrophobic single-isomer cyclodextrin was utilized to separate the enantiomers of weak base analytes in aprotic media by capillary electrophoresis. The effective mobilities and separation selectivities follow trends observed with negatively charged cyclodextrins in amphiprotic solvents. The properties of the dissolved cyclodextrin are altered by its counter ion, thereby affecting the separations of enantiomers. The aprotic media allow the modification of the separation selectivity, since the binding strength of the enantiomers to the cyclodextrin is intermediate between that reported in aqueous and methanolic buffers.

In this study, we prepare the zinc oxide nanotip with aqueous solution deposited on ZnO nucleation layer. The directions of nanotip are formed with different ZnO nucleation layer time. The thermal annealing with N2 ambiance at 300 ¢J for 1 hr increase the UV emission and decrease the defects. We use ZnO nanotip as an anti-reflection layer because of surface roughness and optical interference. ZnO nanotip with rough surface decreases reflection and enhance the transmission, so we use ZnO nanotip as an anti-reflection layer, after growin ZnO nanotip on solar cell the efficiency of solar cell was enhancement.

The synthesis of the sodium salt of heptakis (2, 3-di-O-acetyl-6-O-sulfo)-β-cyclodextrin was modified to increase the isomeric purity to 98.5%. This salt was used to obtain the organic-solvent-soluble, single-isomer, charged tetrabutylammonium salt of heptakis (2, 3-di-O-acetyl-6-O-sulfo)-β-cyclodextrin. Its isomeric purity was higher than 99%, as determined by CE, and its structure was confirmed by NMR and ESI-MS analysis. The hydrophobic single-isomer cyclodextrin was utilized to separate the enantiomers of weak base analytes in aprotic media by capillary electrophoresis. The effective mobilities and separation selectivities follow trends observed with negatively charged cyclodextrins in amphiprotic solvents. The properties of the dissolved cyclodextrin are altered by its counter ion, thereby affecting the separations of enantiomers. The aprotic media allow the modification of the separation selectivity, since the binding strength of the enantiomers to the cyclodextrin is intermediate between that reported in aqueous and methanolic buffers.

In this study, we prepare the zinc oxide one-dimensional nanostructures with aqueous solution on GaN substrate. The morphologies of nanotip, nanorod and nanotube are formed with different modulation and chemical solutions. The thermal annealing with N2O ambiance at 300 ¢XC for 1 hr increase the UV emission and decrease the defects. The limit of choosing the substrate to grow ZnO nanostructures is lattice mismatch between ZnO and substrate. The buffer layer is sputtered on substrate to remove the limit. The pattern of buffer layer also can be used for selective area growth. Nanotip structure with rough surface shows the obvious lotus effect and nanotube structure with more active site and more surface area shows the better photocatalysis efficiency than nanotip structure.

No description available.

Group 13 metals play a pivotal role in many areas of research ranging from materials to environmental chemistry. An important facet of these disciplines is the design of discrete molecules that can serve as functional materials for electronics applications and modeling studies. A solution-based synthetic strategy for the preparation of discrete Group 13 hydroxo-aquo tridecamers with utility as single-source precursors for amorphous functional thin film oxides is introduced in this dissertation. Several techniques including 1H-Nuclear Magnetic Resonance (NMR) spectroscopy, 1H-Diffusion Ordered spectroscopy, Solid-state NMR, Dynamic Light Scattering, and Raman spectroscopy are used to acquire structural information necessary for understanding the nature of these precursors in both the solid and solution phases. The dynamic behavior of these compounds has encouraged additional experiments that will pave the way for new studies with significant importance as the environmental ramifications of these compounds become relevant for future technologies. This dissertation includes previously published and unpublished co-authored material.

In this study the use of seeded microfiltration (MF) with modified powdered carbon focussed on the removal of copper ions from an aqueous solution. The aim of the study was to look into the possibility of utilisation of suitable modified activated carbons combined with membrane filtration (microfiltration) as an alternative technique for the treatment and recovery of copper ions from liquid wastes, to give high removal efficiency with low energy consumption. To enhance the filtration process, the particle size of modified activated carbon used was small because it provides a larger surface area and a shorter diffusional distance for base metals to be adsorbed. Furthermore, in order to minimise the fouling effect, a surface filter (nickel membrane) which had pores, or slots, that passed directly from one side of the filter to the other with no tortuosity was used.

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Made available in DSpace on 2014-10-09T12:36:40Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:59:09Z (GMT). No. of bitstreams: 1 04225.pdf: 3657624 bytes, checksum: 1c1f3312aa7ca8c7b185e9209815c228 (MD5) / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP