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Alkane elimination reaction of Hf(CH2SiMe3) 4 with a zwitterionic salt 1-Me2NHCH2CH2 -1,3-C2B10H12 has resulted in the isolation and structurally characterization of the first example of half-sandwich group 4 metallacarborane alkyls of the C2B10 system. This is also a new route to high-valent group 4 metallacarboranes. / Alkane or amine elimination reactions are also effective methods for the preparation of half-sandwich group 4 metal] acarboranes of the C 2B9 system. The Lewis base functionalized sidearm can effectively stabilize half-sandwich group 4 metallacarborane alkyls through intramolecular coordination. These novel metallacarborane alkyls undergo insertion reaction with alkyne and intramolecular hydrogen atom abstraction reactions. / High-valent group 4 half-sandwich metallacarboranes incorporating an eta 7-carboranyl ligand have been prepared and structurally characterized. The heteroatom-containing pendant sidearms on the carborane cage are both electronically and entropically necessary for the formation of such complexes. / Reaction of [(Me2NCH2CH2)C2B 10H11]Na2 with YCl3 gives eta 1:eta6-[(Me2NCH2CH2)C 2B10H11]YCl(THF)3 containing an exopolyhedral Y-Cl bond, which offers an important intermediate for the preparation of lanthanacarboranes bearing the Ln-C or Ln-X (X = heteroatoms) bonds. On the other hand, it implies that Lewis base functionalized carboranes can stabilize half-sandwich metallacarboranes via the coordination of heteroatom from the sidearm. Silylamine elimination reactions of the neutral ligand 7-Me2NHCH2CH2-7,8-C 2B9H11 with Ln[N(SiHMe2)2] 3(THF)2 are effective method for the preparation of half-sandwich lanthanacarboranes. / Reactions of alkali metal salt of these carboranes with LnCl3 in the presence of excess alkali metal afford a novel class of 13-vertex closo-metallacarboranes incorporating eta7-carboranyl ligands [{eta1:eta1:eta7-[(DCH 2CH2)RC2B10H10]Ln}{Na(solvent) x}]n. Structural studies show that the Lewis base functionalized sidearms have some effects on the coordination environments of the central metal atom, but do not change the gross structures of the 13-vertex closo-metallacarboranes. The reactivity patterns of these 13-vertex closo-metallacarboranes have been studied for the first time. / Several mono- and bisfunctional carboranes (DCH2CH2)RC 2B10H10 (R = H, DCH2CH2, D = MeO, Me2N) have been designed and successfully synthesized. They can be conveniently converted into the monoanions, the dianions and the tetraanions by treatment with suitable reagents. Their applications in organolanthanide and group 4 organometallic chemistry have been studied. / Cheung Mak-shuen. / "June 2005." / Adviser: Kevin W. P. Leung. / Source: Dissertation Abstracts International, Volume: 67-01, Section: B, page: 0258. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 169-181). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

Ren, Zhiyuan. / "March 2001." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 137-143). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Wong, Man Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references (leaves 173-188). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgements --- p.v / Table of Contents --- p.vii / List of Tables --- p.xi / List of Figures --- p.xiii / List of Plates --- p.xv / Chapter Chapter 1 --- Introduction / Chapter 1.1 --- Definition of Rare earth elements --- p.1 / Chapter 1.2 --- Discovery of REEs --- p.5 / Chapter 1.3 --- Physical and chemical properties of REEs --- p.6 / Chapter 1.4 --- Abundance of REEs on earth --- p.10 / Chapter 1.4.1 --- Bastnasite --- p.11 / Chapter 1.4.2 --- Monazite --- p.14 / Chapter 1.4.3 --- Xenotime --- p.16 / Chapter 1.5 --- Reserves and resources --- p.16 / Chapter 1.5.1 --- World reserves --- p.16 / Chapter 1.5.2 --- REE resources in China --- p.18 / Chapter 1.6 --- Production and demand of REEs --- p.20 / Chapter 1.6.1 --- Production and demand in US --- p.21 / Chapter 1.6.2 --- Production and export in China --- p.23 / Chapter 1.6.3 --- Production in other countries --- p.24 / Chapter 1.7 --- Separation of REEs --- p.24 / Chapter 1.7.1 --- Classical methods --- p.24 / Chapter 1.7.2 --- Modern methods --- p.25 / Chapter 1.7.2.1 --- Ion exchange separation --- p.25 / Chapter 1.7.2.2 --- Solvent extraction --- p.25 / Chapter 1.8 --- Applications --- p.26 / Chapter 1.8.1 --- Alloys --- p.26 / Chapter 1.8.2 --- Permanent magnets --- p.28 / Chapter 1.8.3 --- Catalysts --- p.29 / Chapter 1.8.4 --- Glass additives --- p.30 / Chapter 1.8.5 --- Phosphors in television screens and similar fluorescent surfaces --- p.31 / Chapter 1.8.6 --- Fertilizers and feed additives --- p.32 / Chapter 1.9 --- REEs in the environment --- p.33 / Chapter 1.9.1 --- REEs in soil --- p.33 / Chapter 1.9.2 --- REEs in plants --- p.35 / Chapter 1.10 --- Overview of toxicological studies of REEs --- p.36 / Chapter 1.11 --- Current study --- p.38 / Chapter 1.11.1 --- Thesis outline --- p.3 8 / Chapter 1.11.2 --- Objectives --- p.38 / Chapter 1.11.3 --- Significance --- p.39 / Chapter Chapter 2 --- Phytotoxicity of rare earth elements / Chapter 2.1 --- Introduction --- p.41 / Chapter 2.1.1 --- Ecotoxicity of REEs --- p.41 / Chapter 2.1.2 --- Toxicity tests using higher plants --- p.43 / Chapter 2.1.3 --- Advantages of seed germination and root elongation test --- p.44 / Chapter 2.1.4 --- Selection of species --- p.46 / Chapter 2.1.5 --- Endpoint of test --- p.47 / Chapter 2.1.6 --- Median effect estimates --- p.50 / Chapter 2.1.7 --- Objective --- p.50 / Chapter 2.2 --- Materials and methods --- p.50 / Chapter 2.2.1 --- Test species --- p.51 / Chapter 2.2.2 --- Test chemicals --- p.51 / Chapter 2.2.3 --- Range finding test --- p.51 / Chapter 2.2.4 --- Definitive test --- p.52 / Chapter 2.2.5 --- Statistical analyses --- p.52 / Chapter 2.3 --- Results --- p.53 / Chapter 2.3.1 --- Range finding test --- p.53 / Chapter 2.3.2 --- Definitive test --- p.53 / Chapter 2.3.2.1 --- Germination rate --- p.53 / Chapter 2.3.2.2 --- Root length --- p.55 / Chapter 2.3.2.3 --- Germination index --- p.58 / Chapter 2.3.3 --- The median effective concentration --- p.61 / Chapter 2.4 --- Discussion --- p.62 / Chapter 2.4.1 --- Dose-response curves of REEs --- p.62 / Chapter 2.4.2 --- Relative toxicity of the four REEs --- p.63 / Chapter 2.4.3 --- Mechanism of effect of REEs on seed growth --- p.67 / Chapter 2.4.4 --- Comparison between different endpoints --- p.68 / Chapter 2.4.5 --- Comparison between different species --- p.70 / Chapter 2.4.6 --- Limitations and improvement --- p.71 / Chapter 2.4.7 --- Methods of measuring root length --- p.72 / Chapter 2.5 --- Conclusions --- p.73 / Chapter Chapter 3 --- Growth of tree seedlings in soil treated with rare earth elements / Chapter 3.1 --- Introduction --- p.75 / Chapter 3.2 --- Materials and methods --- p.77 / Chapter 3.2.1 --- Soil --- p.77 / Chapter 3.2.2 --- Tree seedlings --- p.77 / Chapter 3.2.3 --- REEs --- p.78 / Chapter 3.2.4 --- Greenhouse experiment --- p.78 / Chapter 3.2.5 --- Soil analysis --- p.80 / Chapter 3.2.5.1 --- Initial properties --- p.80 / Chapter 3.2.5.2 --- Post harvest analysis --- p.81 / Chapter 3.2.6 --- Plant analysis --- p.83 / Chapter 3.2.7 --- Statistical analysis --- p.83 / Chapter 3.3 --- Results --- p.84 / Chapter 3.3.1 --- Growth --- p.84 / Chapter 3.3.1.1 --- Height --- p.84 / Chapter 3.3.1.2 --- Basal diameter --- p.87 / Chapter 3.3.1.3 --- Biomass --- p.89 / Chapter 3.3.1.4 --- Standing leaf number --- p.92 / Chapter 3.3.1.5 --- Chlorophyll fluorescence --- p.95 / Chapter 3.3.2 --- Tissue contents --- p.97 / Chapter 3.3.2.1 --- REEs concentrations --- p.97 / Chapter 3.3.2.2 --- Nitrogen concentrations --- p.99 / Chapter 3.3.2.3 --- Phosphorus concentration --- p.101 / Chapter 3.3.2.4 --- Mineral concentrations --- p.102 / Chapter 3.3.3 --- Soil --- p.104 / Chapter 3.3.3.1 --- Initial properties --- p.104 / Chapter 3.3.3.2 --- REEs concentrations --- p.106 / Chapter 3.3.3.3 --- Nitrogen and phosphorus concentrations --- p.107 / Chapter 3.3.3.4 --- Mineral concentrations --- p.109 / Chapter 3.4 --- Discussion --- p.110 / Chapter 3.4.1 --- Effects of REEs on growth --- p.110 / Chapter 3.4.2 --- Mechanisms of the effect of REEs --- p.112 / Chapter 3.4.3 --- Nutrient uptake --- p.114 / Chapter 3.4.4 --- Soil nutrient contents --- p.116 / Chapter 3.4.5 --- Comparison between REEs --- p.118 / Chapter 3.4.6 --- Comparison between species --- p.121 / Chapter 3.5 --- Conclusions --- p.123 / Chapter Chapter 4 --- Bioavailability and accumulation of rare earth elements / Chapter 4.1 --- Introduction --- p.124 / Chapter 4.2 --- Materials and Methods --- p.126 / Chapter 4.2.1 --- Soil --- p.126 / Chapter 4.2.2 --- Tree seedlings --- p.126 / Chapter 4.2.3 --- Pot experiment --- p.127 / Chapter 4.2.4 --- Chemical speciation of soil --- p.129 / Chapter 4.2.5 --- Statistical analysis --- p.130 / Chapter 4.3 --- Results --- p.130 / Chapter 4.3.1 --- Plant performance --- p.130 / Chapter 4.3.2 --- Tissue contents of La --- p.144 / Chapter 4.3.3 --- Soil --- p.144 / Chapter 4.3.3.1 --- Soil final pH --- p.146 / Chapter 4.3.3.2 --- Soil La contents --- p.146 / Chapter 4.3.4 --- "Association between pH, organic matter and La contents in soil and plant" --- p.149 / Chapter 4.4 --- Discussion --- p.151 / Chapter 4.4.1 --- Growth performance of tree seedling on different soil conditions --- p.151 / Chapter 4.4.2 --- Comparison between growth parameters --- p.152 / Chapter 4.4.3 --- Speciation in soils --- p.154 / Chapter 4.4.4 --- Bioavailability of REEs in soil --- p.155 / Chapter 4.4.5 --- Factors affecting bioavailability of REEs --- p.158 / Chapter 4.4.6 --- Distribution of REEs in plants --- p.162 / Chapter 4.5 --- Conclusions --- p.165 / Chapter Chapter 5 --- General conclusions --- p.167 / Chapter 5.1 --- Summary of major findings --- p.167 / Chapter 5.2 --- Suggestions for further investigation --- p.171 / References --- p.173

Typescript. / Digitized by Kansas Correctional Industries

The corrosion protection of aluminium alloys is of high importance, particularly in the aerospace industry. The most widely used technologies utilise Chromium(VI) compounds for conversion coatings and primer additives in paint systems to provide corrosion protection to these alloys. These compounds are highly toxic, carcinogenic and detrimental to the environment, therefore the identification of alternative systems that are safe and environmentally benign, that meet or exceed the current levels of corrosion protection is vital. This research program examines the corrosion inhibition effectiveness of selected rare earth diphenyl phosphates (RE(dpp)3). These compounds incorporate known inhibitor species, namely rare earth metals, organics and phosphates into a single complex, with the aim of achieving synergistic inhibition in corrosive environments. A screening study utilising immersion and weight loss experiments identified Cerium diphenyl phosphate (Ce(dpp)3) and Mischmetal diphenyl phosphate (Mm(dpp)3) as the most effective inhibitors of corrosion for AA2024-T3. The inhibiting efficiency, mechanism of inhibition and surface interaction of these complexes on aluminium alloy AA2024-T3 was characterised using a range of electrochemical and surface techniques. A similar study was carried out using AA7075-T6 to assess the adaptability of the RE(dpp)3 compounds to protect different alloy compositions. The complexes were effective in significantly reducing the corrosion rate of the alloys, with both the cathodic and anodic corrosion processes being suppressed. This mixed inhibition was not attained with the constituent rare earth and diphenyl phosphate ions individually, indicating the need for the complex to remain intact in solution to achieve the high level of corrosion protection observed. The initiation and propagation of surface pits was effectively suppressed by the RE(dpp)3 complexes. The combination of electrochemical and surface characterisation techniques has for the first time allowed insights into the mechanism of action of these compounds on aluminium alloys, and indicated deposition was initiated at electrochemically active intermetallic particles. The mixed rare earth phases present in Mm(dpp)3 produced a synergistic effect, providing a greater degree of corrosion protection compared with Ce(dpp)3, particularly on AA2024-T3. In the final phase of this research project the RE(dpp)3 inhibitor compounds were incorporated into an epoxy coating system, and demonstrated that the initiation of filiform corrosion on AA2024-T3 could be reduced by up to a factor of 3 by their addition. The growth rate of filaments was also impeded.

Bibliography: leaves 132-147.

In this work the phase behaviour of noble gases is studied comprehensively by different molecular simulation methods using different intermolecular potentials. The aim is to investigate three-body effects on the phase behaviour of noble gases. A true two-body potential model (Barker-Fisher-Watts potential) and the three-body potential model (Axilrod-Teller term) have been used. The results obtained from the two-body BFW potential with the three-body Axilrod-Teller potential included for the vapour-liquid and solid-liquid phase equilibrium properties of pure noble gases are compared with the calculations using the Lennard-Jones potential with different suggested parameter values. The results have been compared with experimental data and the best parameter values for simulating the thermodynamic properties of noble gases are found. Three-body effects on the phase behaviour of noble gases are reported for a large range of density, temperature and pressure. Simple relationships have been found between two-body and three-body potential energies for pure fluids and solids. Three-body effects on the vapour-liquid phase equilibrium properties of argon, krypton, xenon and argon-krypton systems are studied by the Gibbs-Duhem integration Monte Carlo method. Three-body effects on the solid-liquid phase equilibrium properties of argon, krypton and xenon are investigated by non-equilibrium and equilibrium molecular dynamics techniques. All the calculations have been compared with experimental data, which show that three-body interactions play an important role in the overall interatomic interactions of noble gases.

Thesis (Ph. D.)--Oregon Graduate Center, 1976.

Although complete understanding of the mechanisms of rare genetic variants in disease continues to elude us, Next Generation Sequencing (NGS) has facilitated significant gene discoveries across the disease spectrum. However, the cost of NGS hinders its use for identifying rare variants in common diseases that require large samples. To circumvent the need for larger samples, designing efficient sampling studies is crucial in order to detect potential associations. This research therefore evaluates sampling designs for rare variant - quantitative trait association studies and assesses the effect on power that freely available public cohort data can have in the design. Performing simulations and evaluating common and unconventional sampling schemes results in several noteworthy findings. Specifically, the extreme-trait design is the most powerful design for analyzing quantitative traits. This research also shows that sampling more individuals from the extreme of clinical interest does not increase power. Variant filtering has served as a "proof-of-concept" approach for the discovery of disease-causing genes in Mendelian traits and formal statistical methods have been lacking in this area. However, combining variant filtering schemes with existing rare variant association tests is a practical alternative. Thus, this thesis also compares the robustness of six burden-based rare variant association tests for Mendelian traits after a variant filtering step in the presence of genetic heterogeneity and genotyping errors. This research shows that with low locus heterogeneity, these tests are powerful for testing association. With the exception of the weighted sum statistic (WSS), the remaining tests were very conservative in preserving the type I error when the number of affected and unaffected individuals was unequal. The WSS, on the other hand, had inflated type I error as the number of unaffected individuals increased. The framework presented can serve as a catalyst to improve sampling design and to develop robust statistical methods for association testing.