Düsseldorf, Universiẗat, Diss., 2000.

Freiberg (Sachsen), Techn. Universiẗat, Diss., 2002.

This thesis describes a study of the low temperature specific heat of LiⅹNbS₂, where x is between 0 and 1. Samples were prepared by intercalating lithium into niobium disulfide in electrochemical cells. Structural data obtained by x-ray diffraction are presented. These, together with electrochemical measurements, show that staged phases exist for some values of x. The electronic specific heat of LiⅹNbS₂, is consistent with complete charge transfer from the intercalated lithium to the bands of the NbS2 host. The lattice specific heat also shows large changes as a function of x. A discussion of the data in terms of continuum elasticity theory suggests that intercalation produces large changes in the shear elastic constant C₄₄ . A brief discussion of superconductivity in LiⅹNbS₂, is also included. / Science, Faculty of / Physics and Astronomy, Department of / Graduate

We have elucidated the structures of a series of Werner Clathrates with systematically changing guest molecules. The host is the inorganic coordination compound bis(isothiocyanato)tetra(4-vinylpyridine)nickel(II), [Ni(NCS)2(4-ViPy)4]. The guests are mixtures of tetrahydrofuran and the cyclic hydrocarbons: cyclohexane, cyclohexene, 1,3-cYclohexadiene, 1,4-cyclohexadiene and benzene. Host to guest ratios were elucidated by density and proton nuclear magnetic resonance spectroscopy. The thermal characteristics of the compounds were analysed by thermogravimetric analysis and differen.tial thermal analysis. The structures of two related compounds [Ni(NCS)2(Py)4] and [Ni(NCS)2(Py)4].nbenzene were also studied.

Includes bibliographical references. / The crystal structures of trans-9, 10-dihydroxy-9, 10-diphenyl-9, 10- dihydroanthracene with various guest molecules have been determined by X-ray diffraction. The guests were 2-butanone, 4-vinylpyridine, 4-methylpyridine and 2-methylpyridine. The host to guest ratios were determined by microanalysis and density measurements. The change of the overall host lattice structure upon guest release was studied by X-ray powder diffraction. The thermal characteristics of the compounds were studied using thermogravimetric analysis and differential scanning calorimetry. Guest desorption from three of the four compounds occurred in a single step whereupon the host framework collapsed back to the guest-free structure. The compound containing 4-methylpyridine, released the guest molecules in a two-step process. Evidence of a new host phase was identified from the XRD pattern of this intermediate phase. On further guest release, the intermediate phase converted to the guest-free host structure. In an attempt to reconcile thermodynamics with structure, the correlation between hydrogen bond length and guest desorption enthalpy was investigated.

by Yuet-ming Man. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 49-52.

by Chi-Keung Lam. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 100-103). / Abstract also in Chinese. / Acknowledgments --- p.i / Abstract --- p.ii / 摘要 --- p.iii / Table of contents --- p.iv / Index of compounds --- p.v / List of tables --- p.vi / List of figures --- p.vii / Chapter Chapter 1. --- Introduction / Chapter 1.1 --- Some aspects of urea/thiourea inclusion chemistry --- p.1 / Chapter 1.2 --- General chemistry of monocyclic oxocarbons --- p.5 / Chapter 1.2.1 --- Synthesis of monocyclic oxocarbons --- p.5 / Chapter 1.2.2 --- Aromaticity of monocyclic oxocarbon anions --- p.20 / Chapter 1.2.3 --- Reactions of monocyclic oxocarbons --- p.25 / Chapter 1.3 --- Aim of the present research --- p.31 / Chapter Chapter 2. --- Description of crystal structures / Chapter 2.1 --- Urea-anion inclusion compounds --- p.32 / Chapter 2.1.1 --- Bis(tetra-n-propylammonium) squarate-urea-water (1/ 6/2) --- p.32 / Chapter 2.1.2 --- Tetra-n-butylammonium hydrogen squarate-urea-water (1/1/1) --- p.38 / Chapter 2.1.3 --- Bis(tetraethylammonium) squarate-tetraethylammonium hydrogen carbonate- urea-water (1/2/4/6) --- p.42 / Chapter 2.1.4 --- Bis(tetra-n-propylammonium) croconate-urea-water (1/5/2) --- p.47 / Chapter 2.2 --- Thiourea-anion inclusion compounds --- p.53 / Chapter 2.2.1 --- Bis(tetraethylammonium) squarate-thiourea-water (1/4/ 2) --- p.53 / Chapter 2.2.2 --- Bis(tetraethylammonium) squarate-thiourea (1/6) --- p.59 / Chapter 2.2.3 --- Bis(tetra-n-propylammonium) squarate-thiourea-water (1/ 4/2) --- p.66 / Chapter Chapter 3. --- Summary and discussion / Chapter 3.1 --- Urea/thiourea monocyclic oxocarbon anions inclusion compounds --- p.71 / Chapter 3.2 --- Structural features and topological correlations of the host lattices --- p.72 / Chapter 3.3 --- Hydrogen bonding and linkage modes of urea and thiourea molecules --- p.87 / Chapter Chapter 4. --- Experimental / Chapter 4.1 --- Preparation of crystals --- p.91 / Chapter 4.2 --- X-ray Crystallography --- p.93 / References --- p.100 / Appendix Atomic coordinates and thermal parameters of the new inclusion compounds --- p.104

No description available.

The unscheduled formation of gas hydrate plugs in oil and gas pipelines, which can lead to serious mechanical and personnel damage, is a problematic issue in the petroleum industry. Traditionally, thermodynamic inhibitors such as methanol have been used to control the formation of gas hydrates, but due to the large expenses and ecological risks associated with its use there is increased interest in the use of alternative hydrate inhibitors. They include kinetic inhibitors (KIs) and antiagglomerants (AAs) and as their names imply, function by interfering with the kinetics of hydrate formation and hydrate agglomeration. Recently, antifreeze proteins (AFPs) have shown to inhibit hydrates and have been proposed as hydrate inhibitors. Normally, AFPs function to protect the tissues of various organisms during freezing conditions. Initially they were found in polar fish, and were later recognized in insects, plants and microorganisms. AFPs are thought to function by lowering the freezing point of water through an adsorption-inhibition mechanism. This thesis has shown that antifreeze proteins (AFPs) are able to modify the crystal morphologies of structure II (sII) tetrahydrofuran (THF) similarly to the KI poly-N-vinylpyrrolidone (PVP) by adhering to the hydrate surface and inhibiting crystal growth. The AFPs were also tested on a high-pressure sII methane/ethane/propane hydrate and proved to have superior hydrate inhibition to PVP. Yet, the expense of purifying AFPs makes them impractical for industrial purposes, thus investigations into the use of cold-adapted bacteria as hydrate inhibitors proved that isolates capable of adsorbing to THF hydrate showed the most effective THF hydrate inhibition. These findings suggest a potential for the future development of biologically-based hydrate inhibitors. / Thesis (Master, Biology) -- Queen's University, 2009-09-01 10:04:00.72

Thesis (Ph.D.)--Tufts University, 1999. / Adviser: Terry Haas. Submitted to the Dept. of Chemistry. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;