Ho, Yuk Ting. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2007. / Includes bibliographical references. / Abstracts in English and Chinese. / Acknowledgement --- p.i / Abstract --- p.vi / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Composite Materials --- p.1 / Chapter 1.2 --- General Properties of Composite Materials --- p.2 / Chapter 1.3 --- Fabrication of Composite Materials --- p.3 / Chapter 1.3.1 --- Liquid State Sintering --- p.4 / Chapter 1.3.2 --- Casting --- p.6 / Chapter 1.3.3 --- Other Fabrication Techniques --- p.7 / Chapter 1.4 --- Phase Transformation --- p.8 / Chapter 1.5 --- Nucleation and Growth --- p.10 / Chapter 1.5.1 --- Homogeneous nucleation --- p.10 / Chapter 1.5.2 --- Heterogeneous nucleation --- p.10 / Chapter 1.5.3 --- Growth --- p.11 / Chapter 1.6 --- Phase Separation by Spinodal Decomposition --- p.11 / Chapter 1.6.1 --- The Initiation of Spinodal Decomposition --- p.12 / Chapter 1.6.2 --- Dynamics of Spinodal Decomposition --- p.12 / Chapter 1.6.3 --- Difference between Coherent Spinodal and Nucleation and Growth --- p.17 / Chapter 1.7 --- Methods in Obtaining Large Under-cooling --- p.19 / References --- p.20 / Figures --- p.23 / Chapter Chapter 2 --- Experiment --- p.29 / Chapter 2.1 --- Introduction --- p.29 / Chapter 2.2 --- Preparation of Fused Silica Tubes --- p.29 / Chapter 2.3 --- Sample Preparation --- p.30 / Chapter 2.3.1 --- Alloying --- p.30 / Chapter 2.3.2 --- Fluxing --- p.30 / Chapter 2.3.3 --- Under-cooling --- p.31 / Chapter 2.4 --- Microstructure Analysis --- p.32 / Chapter 2.4.1 --- Sample Surface Analysis --- p.32 / Chapter 2.4.2 --- Scanning Electron Microscopy (SEM) --- p.32 / Chapter 2.5 --- Transmission Electron Microscopy (TEM) --- p.32 / Chapter 2.5.1 --- Specimen Requirement --- p.33 / Chapter 2.5.2 --- "Cutting, Grinding, Polishing and Pouching" --- p.33 / Chapter 2.5.3 --- Dimpling --- p.34 / Chapter 2.5.4 --- Ion Milling --- p.34 / Chapter 2.5.5 --- Microstructure Characterization by TEM --- p.35 / Chapter 2.6 --- Mechanical Properties --- p.37 / Chapter 2.6.1 --- Hardness Testing --- p.37 / Chapter 2.6.2 --- Compression Testing --- p.37 / Chapter 2.7 --- Characterizations of Untreated Samples --- p.38 / References --- p.39 / Figures --- p.40 / Chapter Chapter 3 --- Formation and Properties of Co-Si-B Metal Matrix Composites --- p.44 / Abstract --- p.44 / Introduction --- p.45 / Experimental --- p.46 / Results --- p.47 / Chapter A. --- Microstructures --- p.48 / Eutectic Co75Si15B10 --- p.48 / Network Co75Si15B10 --- p.48 / Chapter B. --- Mechanical Behavior --- p.50 / Eutectic Co75Si15B10 --- p.50 / Network CO75Si15B10 --- p.51 / Discussions --- p.53 / Conclusion --- p.53 / Acknowledgement --- p.54 / References --- p.55 / Figures --- p.56 / Chapter Chapter 4 --- On the Network Morphology of Co75Si15B10 Alloys --- p.68 / Abstract --- p.68 / Introduction --- p.69 / Experimental --- p.69 / Results --- p.69 / Discussions --- p.74 / Acknowledgement --- p.77 / References --- p.78 / Figures --- p.79 / Chapter Chapter 5 --- Conclusion --- p.100

No description available.

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Graduation date: 1993

Thesis (Ph. D.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 263-285).

Thesis (Ph. D.)--University OF MICHIGAN.

Thesis (Ph. D.)--University of Hong Kong, 2010. / Includes bibliographical references. Also available in print.

published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

abstract / Chemistry / Doctoral / Doctor of Philosophy

A library of luminescent cyclometalated gold(III) complexes containing various bis-cyclometalating R-C^N^C ligands derived from 2,6-diphenylpyridine and ancillary alkynyl ligands, [Au(R-C^N^C)(C≡CR’)], has been synthesized. Some of the complexes have been structurally determined by X-ray crystallography. These complexes were found to exhibit intense emission in dichloromethane solution at 298 K, originating from metal-perturbed triplet intraligand (IL) excited states of the R-C^N^C ligand, with substantial charge transfer character from the aryl moiety to the pyridyl ring. In the presence of electron-rich alkynyl ligands, the emission origin could be switched to an alkynyl-to-cyclometalating ligand ligand-to-ligand charge transfer (LLCT) excited state. This class of complexes was also demonstrated to show rich electroluminescence properties as emitters in organic light-emitting devices. In addition, the supramolecular assembly of this class of complexes has also been revealed in gelation studies. N-Heterocyclic carbenes have been incorporated into the gold(III) metal center to prepare a series of luminescent mononuclear and dinuclear gold(III) complexes, [{Au(C^N^C)}n(NHC)](PF6)n and [{Au(tBuC^N^CtBu)}n(NHC)]- (PF6)n (n = 1, 2). The X-ray crystal structures of most of the complexes have been determined. The emissions of these complexes were assigned to originate from the metal-perturbed intraligand excited state of the bis-cyclometalating ligand. One of the C2-bridged dinuclear complexes was found to exhibit two distinct reduction couples, tentatively correlated to the presence of significant intramolecular π-π interaction in the complex. Two novel series of luminescent mononuclear alkynylgold(III) complexes, [Au(C^N)(C≡CR)2] (HC^N = 2-phenylpyridine (Hppy) and derivatives) and [Au(C^N^N)(C≡CR)]PF6 (HC^N^N = 6-phenyl-2,2’-bipyridine and derivatives), have been synthesized. Some of the X-ray crystal structures have been determined. The former class of complexes with bidentate C^N ligands has been observed to show tunable emission spanning across the visible spectrum from 462 to 697 nm. With the exception of [Au(ppy)(C≡C-C6H4-NH2-p)2] which showed a low-energy band originated from a 3LLCT [π(C≡C-C6H4-NH2)→π*(C^N)] excited state, all complexes exhibited vibronic-structured emission bands originated from the intraligand transition of the cyclometalating C^N ligand in dichloromethane solution at 298 K. On the other hand, most of the complexes with the tridentate C^N^N-type ligand have been observed to exhibit vibronic-structured emission bands attributed to the intraligand transition of the C^N^N ligand in low-temperature butyronitrile glass. / published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy