No description available.

Lithium salts of pentafluorothio alkyl sulfonic acids and perfluoroalkyl disulfonic acids were prepared for testing for possible use as polymer electrolytes. Most of these lithium salts were made from the corresponding sodium, potassium or calcium salts. Aqueous solutions of these salts were passed through polystyrene sulfonate ion exchange resin in the acid form to obtain aqueous solutions of the corresponding acids. The acids were then neutralized with lithium hydroxide using a pH meter. One salt was made by reacting the barium salt of the corresponding acid with lithium sulfate. A sulfonyl fluoride polymer (-0-CH2-C (CH20CF2CF2S02F) H-) n was reacted with lithium hydroxide to give a lithium salt as well. Owing to the great length of time required to dry these hydroscopic salts so that they might be suitable for polymer electrolyte work, alternative, water-free methods of preparation were explored. These include the reaction of lithium trimethylsilanolate with a sulfonyl fluoride, and the reaction of trimethylsilyl triflate with lithium chloride. Conductivity studies were performed on samples of these salts, and the results so far obtained from these studies are presented. Mass spectrometry, 1H, 19F and 13C nuclear magnetic resonance spectroscopy, infrared spectroscopy, and elemental analysis were used to help characterize the new lithium salts.

The field of industrial fluorine generation has not made significant progress in the past 60 years due to the difficulty and hazards surrounding the use of hydrofluoric acid (HF) and fluorine gas. This work examines various carbon materials for their use as electrodes in the electrochemical generation of elemental fluorine. An experimental apparatus was designed and constructed to melt and maintain the temperature of the KF·2HF electrolyte in a suitable range for electrochemical measurements. An electrochemical cell was designed and tested for operations in a highly corrosive atmosphere at elevated temperatures. The importance of safe operating procedures surrounding HF is outlined in this work. Various in-situ electrochemical techniques were used to study the ability of the different carbon anode materials in their ability to carry out the fluorine discharge reaction (FDR) as well as study the growth of passivating film. Ex-situ analytical techniques were used to examine the microstructure and composition of the carbon materials before and after electrochemical polarization. The results suggest that the level of non-carbon impurities had the most significant effect on the ability of the carbon material to carry out the FDR efficiently at most potentials tested. The results show that multiple analytical techniques are required to obtain a better understanding of a chemical system, and that no single method can be used to fully explain a single set of results. / UOIT

This thesis is to research connection process of multi-level conductor in integration circuits (ICs) manufacture technology. For the sake of sub-micro ICs which is gazed by people in the future, device¡¦s dimension have to be scaled down unceasingly; besides, the design of conductor connection of multi-level metal is also to be adopted for ULSI technology. However, the number of metal connection layer is increasing as well as the distance between wires is shorter and shorter, which leads to the fact that the RC delay time of metal interconnection is the primary reason of limiting the speed of semiconductor device while electronic signal is delivered among metal interconnection. In order to lower delay time of signal propagation, there are two parts in the following: In the aspect of lowering resistance, we substitute copper (resistance is 1.7£g£[-cm) at present for aluminum (resistance is 2.7£g£[-cm ) in the past so as to make copper be the wire for interconnection system. Furthermore, the scaled down device not only increase the current density of the wire but also increase the severity of electromigration inside the wire. Copper atoms are so heavier than aluminum atoms that copper atoms can restrain electromigration appropriately. In the aspect of decreasing capacitance, we will develop low dielectric constant (low-k). But copper with Damascene manufacture under the conditions of external operation such as temperature and electric field give rise to the fact that Cu diffuses into low-k material so easily that copper and low-k interact, which deteriorates the characteristic of the material¡Braises the leakage current and leads to the breakdown of the dielectric material. Therefore, it must be an important topic for study that we search for the dielectric barrier material with the characteristic against copper diffusion under the demand coinciding with integration process compatibility. At present, because of the material film called silicon carbide with low dielectric constant (k=4~6) attracts a lot of people¡¦s eyes deeply, it can applied to dielectric barrier technology to replace traditional dielectric barrier silicon nitride with high dielectric constant (k~8) for the purpose of alleviating delay time of the wire system. This thesis will discuss fundamental characteristics of silicon carbide film and some problems during the integration process. For instance, the impacts on silicon carbide under the conditions of fluorine plasma and thermal treatment; furthermore, this thesis will research the electric problems from the integration of low-k dielectric barrier and copper wire as well as probes into mechanism of leakage current.

No description available.

Nature has evolved the ability to form a C-F bond, as exemplified by the bacterium Streptomyces cattleya, which elaborates fluoroacetate (FAc) and 4-fluorothreomne (4- FT). The mechanism of this bond formation are unknown. This thesis probes the biosynthesis of fluoroacetate and 4-fiuorothreonine and in doing so explores the C-F bond forming process. Feeding stable isotope enriched primary metabolites to S. cattleya, followed by (^19)F NMR and GCMS analysis of the resultant fluorometabolites, highlights the role of the glycolytic pathway in delivering a substrate for fluorination. 3-Fluoro-l- hydroxypropan-2-one was synthesised and feeding studies eliminate this as the initial product of fluorination. Fluoroacetaldehyde was identified as a common fluorinated intermediate in the biosynthesis of both FAc and 4-FT. Whole cell studies demonstrate the rapid oxidation of fluoroacetaldehyde to FAc. 4-FT is produced in low quantities by S. cattleya incubated with fluoroacetaldehyde. The synthesis and feeding of [1-(^2)H]- fluoroacetaldehyde provide evidence that the resultant 4-FT is biosynthesised from fluoroacetaldehyde. The biotransformation from fluoroacetaldehyde to FAc was shown in cell free studies to be mediated by an aldehyde dehydrogenase, requiring NAD(^4) as a co-factor. The substrate specificity of fluoroacetaldehyde dehydrogenase was probed by spectrophotometrically monitoring the production of NADH in the presence of different aldehydes. Further cell free experiments probed the biosynthetic origins of fluoroacetaldehyde. Glycolaldehyde phosphate and various phosphorylated glycolytic intermediates were incubated with cell free extracts of S. cattleya and a plethora of co-factors. In the absence of observing fluorination activity, it was shown that the cell free extract acts to dephosphorylate the substrates. The putative role of glycolaldehyde phosphate was explored by feeding isotopically labelled glycolaldehydes to whole cells of the bacterium. The results were not consistent with direct conversion from glycolaldehyde phosphate to fluoroacetaldehyde.

Thesis (Ph. D.)--Oregon State University, 2007. / Printout. Includes bibliographical references (leaves 88-95). Also available on the World Wide Web.

Academisch proefschrift--University van Amsterdam. / Summary in Dutch, 4 p., laid in.

Thesis (doctoral)--Københavns tandlaegehøjskole.

Academisch proefschrift--University van Amsterdam. / Summary in Dutch, 4 p., laid in.