Graduation date: 1995

The Hoidas Lake Rare Earth Element (REE) Deposit is one of several REE showings which are spatially associated with a regional-scale fault system that cuts through the Rae Province in northern Saskatchewan. The showings occur along the Hoidas-Nisikkatch fault, believed to be a subsidiary of the Black Bay Fault, and consist of multiple REE-enriched veins. Surface outcrops and drilling have delineated a vein system, called the JAK zone, which extends for over 1 km along strike, with the system remaining open both along strike and down dip. The majority of the REE are hosted by fluorapatite and allanite-(Ce), although there are also minor amounts of monazite, bastnaesite and chevkinite which can contain significant concentrations of REE. The veins are dominantly LREE-enriched, specifically La, Ce, and Nd.<p> The mineralization at Hoidas Lake is complex, with the chemical and mineralogical compositions changing with each vein generation. The earliest veins consist of REE-bearing allanite and chevkinite which occur in association with clinopyroxene, titanite, and hyalophane. The allanite-rich veins are followed by veins dominated by red or green apatite, both of which are typically brecciated. Finally, there is a late apatite which crosscuts all previous vein generations. Each of the distinct apatite generations shows discrete chemical variations, particularly in their light rare earth element content, with the total rare earth oxide content ranging from approximately 1.5% in the oldest apatite to as much as 5% in the green apatite.<p> The majority of the apatite and allanite crystals are strongly zoned, reflecting the chemical changes in the mineralizing system through time and, particularly in the earliest vein generations, there are signs of hydrothermal alteration. The early apatite generations typically show the development of monazite inclusions which suggests interaction with hydrothermal fluids, as do the REE-poor rims and bastnaesite alteration observed in the majority of the allanites.<p> The veins are fault controlled and are interpreted to be late magmatic- hydrothermal in origin, with the fluid derived from a magmatic source at depth. Although the exact source of the fluids remains uncertain, the high concentration of REE, as well as Sr and Ba, and a relative depletion in high field strength elements suggests that the mineralization may be related to either an alkali or carbonatitic source.

The Hoidas Lake Rare Earth Element (REE) Deposit is one of several REE showings which are spatially associated with a regional-scale fault system that cuts through the Rae Province in northern Saskatchewan. The showings occur along the Hoidas-Nisikkatch fault, believed to be a subsidiary of the Black Bay Fault, and consist of multiple REE-enriched veins. Surface outcrops and drilling have delineated a vein system, called the JAK zone, which extends for over 1 km along strike, with the system remaining open both along strike and down dip. The majority of the REE are hosted by fluorapatite and allanite-(Ce), although there are also minor amounts of monazite, bastnaesite and chevkinite which can contain significant concentrations of REE. The veins are dominantly LREE-enriched, specifically La, Ce, and Nd.<p> The mineralization at Hoidas Lake is complex, with the chemical and mineralogical compositions changing with each vein generation. The earliest veins consist of REE-bearing allanite and chevkinite which occur in association with clinopyroxene, titanite, and hyalophane. The allanite-rich veins are followed by veins dominated by red or green apatite, both of which are typically brecciated. Finally, there is a late apatite which crosscuts all previous vein generations. Each of the distinct apatite generations shows discrete chemical variations, particularly in their light rare earth element content, with the total rare earth oxide content ranging from approximately 1.5% in the oldest apatite to as much as 5% in the green apatite.<p> The majority of the apatite and allanite crystals are strongly zoned, reflecting the chemical changes in the mineralizing system through time and, particularly in the earliest vein generations, there are signs of hydrothermal alteration. The early apatite generations typically show the development of monazite inclusions which suggests interaction with hydrothermal fluids, as do the REE-poor rims and bastnaesite alteration observed in the majority of the allanites.<p> The veins are fault controlled and are interpreted to be late magmatic- hydrothermal in origin, with the fluid derived from a magmatic source at depth. Although the exact source of the fluids remains uncertain, the high concentration of REE, as well as Sr and Ba, and a relative depletion in high field strength elements suggests that the mineralization may be related to either an alkali or carbonatitic source.

Radio frequency (RF) filters are one of the key building blocks in modern microelectronic digital communication systems that use a narrow frequency band with strong interferers nearby. The objective of this thesis is to explore the better DR performance of RF filters using the Q-enhanced LC filter. It takes a divide-and-conquer method by designing 1. A new simple pseudo-differential pair (PDP) for input gm stage. It is the fastest, high-linearity, low-distortion, and wide-range constant-gm design reported to date. This has been applied in the final filter tape-out and has proven to be effective experimentally. 2. A new tunable discrete inductor (TDL) to achieve two-level inductance with the same real estate that can be used to expand the filtering frequency range. This has been verified experimentally. 3. A new tunable discrete capacitor (TDC) to achieve high linearity over wide terminal voltage swing range. This has been verified through simulation. 4. A new systematic way to achieve synchronized gain, center frequency, and filtering Q tuning capability for Q-enhanced LC filters. It has been verified through simulation. In order to verify the concept, a 900 MHz filter is designed and fabricated with National Semiconductor Company (NSC)'s standard 0.18 um digital epi-substrate CMOS technology, and packaged with NSC's LLP-28. The measurement results show that with filter Q of 17 at 845 MHz, the 1 dB compression point is measured to be +4 dBm, IIP3 to be +16 dBm with a peak noise floor of -154 dB/Hz, spurious free dynamic range (SFDR) to be 71 dB. With filter Q of 70 over a 20 MHz BW, the 1 dB compression point is measured to be -9.5 dBm, IIP3 to be +7 dBm with a peak noise floor of -141 dB/Hz, SFDR to be 57 over 20 MHz BW. This filter uses between 56 and 60 mA with a power supply of 1.8 V due to the low-Q (Q~1) of inductor. It is the RF filter with the highest DR in the published literature. The DR can be even higher if inductor Q can be improved as DR is proportional to Q^2.

Thesis (Ph. D.)--Auburn University, 2008. / Abstract. Vita. Parts of this dissertation have been published as: Na₂[UO₂(IO₃)₄(H₂O)] (Ch. 2: Bray, T.H.; et al., Inorg. Chem., 2006, 45, 8251-8257.), An(IO₃)₄(An = Np, Pu) and Np(IO₃)₄·nH2O (Ch. 3: Bray, T.H.; et al., Inorg. Chem., 2007, 46, 3663-3668.), Pu(SeO₃)₂ (Ch. 4: Bray, T.H.; et al., J. Solid State Chem., 2008, 181, 493-498.), NpFPO₄ and Cs₂Np₂F₇PO₄ (Ch. 5: Bray, T.H.; et al., J. Solid State Chem., 2007, 180, 70-74.), [C₆H₁₄N₂][(UO₂)₄(HPO₄)₂PO₄)₂(H₂O)]·H₂O (Ch. 6: Bray, T.H.; et al., "Synthesis and Structure of [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)]·H₂O: An Expanded Open-Framework Amine-Bearing Uranyl Phosphate," In press: Journal of Solid State Chemistry April 24, 2008.), and Np(CH₃PO₃)(CH₃PO₃H)(NO₃)(H₂O)·H₂O (Ch. 7: Bray, T.H.; et al., Inorg. Chem., 2007, 46, 10959-10961.). Includes bibliographical references.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references. Also available online.

Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references. Also available in print.

Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also in a digital version from Dissertation Abstracts.

Thesis (M. Phil.)--University of Hong Kong, 1988.

Thesis (M. Phil.)--University of Hong Kong, 1979.