by Lee Wai Lok. / x and 1-x are in title are subscript. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves [67]-[70]). / by Lee Wai Lok. / Abstract --- p.i / Chapter Chapter1 --- Introduction --- p.1-1 / Chapter 1.1 --- Epitaxial Growth --- p.1-2 / Chapter 1.1.1 --- Background of Epitaxy --- p.1-2 / Chapter 1.1.2 --- Operating Principle of OMVPE --- p.1-2 / Chapter 1.1.3 --- Problems in Heteroepitaxy --- p.1-3 / Chapter 1.2 --- Basic Requirements of a Semiconductor Laser --- p.1-3 / Chapter 1.3 --- Our work --- p.1-4 / Chapter Chapter2 --- OMVPE Growth --- p.2-1 / Chapter 2.1 --- Our OMVPE System Design --- p.2-1 / Chapter 2.1.1 --- Growth Environment --- p.2-2 / Chapter 2.1.2 --- Susceptor Temperature Control --- p.2-2 / Chapter 2.1.3 --- Reactor Pressure Control --- p.2-2 / Chapter 2.1.4 --- MO Vapor Handling Control --- p.2-2 / Chapter 2.1.4.1 --- MO Flow Control --- p.2-3 / Chapter 2.1.4.2 --- Flow Path Selection --- p.2-3 / Chapter 2.1.5 --- Cabinet with Air Extraction --- p.2-3 / Chapter 2.1.6 --- Chemical Scrubber --- p.2-4 / Chapter 2.2 --- System Calibration --- p.2-4 / Chapter 2.3 --- Materials Used --- p.2-5 / Chapter 2.3.1 --- Precursor Materials --- p.2-5 / Chapter 2.3.2 --- Hydrogen Gas --- p.2-5 / Chapter 2.3.3 --- Nitrogen Gas --- p.2-6 / Chapter 2.3.4 --- Substrate --- p.2-6 / Chapter 2.4 --- Fabrication Conditions --- p.2-6 / Chapter Chapter3 --- Characterization --- p.3-1 / Chapter 3.1 --- X-ray Diffraction --- p.3-1 / Chapter 3.2 --- EDX Spectroscopy --- p.3-2 / Chapter 3.3 --- Optical Reflectance --- p.3-4 / Chapter Chapter4 --- Data Analysis --- p.4-1 / Chapter 4.1 --- ZnSe/GaAs(100) --- p.4-1 / Chapter 4.1.1 --- Structural Analysis --- p.4-1 / Chapter 4.1.2 --- Stoichiometry --- p.4-2 / Chapter 4.1.3 --- Growth Rate --- p.4-3 / Chapter 4.1.4 --- Energies of Critical Points --- p.4-3 / Chapter 4.1.5 --- Reflectance --- p.4-4 / Chapter 4.2 --- ZnCdSe/InP(100) --- p.4-5 / Chapter 4.2.1 --- Structural Analysis --- p.4-5 / Chapter 4.2.1.1 --- Structural Quality --- p.4-5 / Chapter 4.2.1.2 --- Crystal Structure --- p.4-5 / Chapter 4.2.1.3 --- Lattice Parameter --- p.4-8 / Chapter 4.2.2 --- Composition Range --- p.4-8 / Chapter 4.2.3 --- Degree of Relaxation --- p.4-9 / Chapter 4.2.4 --- Comparison to Prior Art --- p.4-10 / Chapter 4.2.5 --- Growth Rate --- p.4-11 / Chapter 4.2.6 --- Energies of Critical Points --- p.4-12 / Chapter Chapter5 --- Conclusions --- p.5-1 / Appendix A Calculation of the actual MO Mass Flow --- p.6-1 / Appendix B Interpretation of in-plane Lattice Parameter --- p.6-3 / Appendix C Structure Factor of Wurtzite Lattice --- p.6-4 / References --- p.7-1

In radio astronomy wider observing bandwidths are constantly desired for the reasons of improved sensitivity and velocity coverage. As observing frequencies move steadily higher these needs become even more pressing. In order to process wider bandwidths, components that can perform at higher frequencies are required. The chief limiting component in the area of digital spectrometers and correlators is the digitiser. This is the component that samples and quantises the bandwidth of interest for further digital processing, and must function at a sample rate of at least twice the operating bandwidth. In this work a range of high speed digitiser integrated circuits (IC) are designed using an advanced InP HBT semiconductor process and their performance limits analysed. These digitiser ICs are shown to operate at up to 10 giga-samples/s, significantly faster than existing digitisers, and a complete digitiser system incorporating one of these is designed and tested that operates at up to 4 giga-samples/s, giving 2 GHz bandwidth coverage. The digitisers presented include a novel photonic I/O digitiser which contains an integrated photonic interface and is the first digitiser device reported with integrated photonic connectivity. In the complementary area of analogue correlators the limiting component is the device which performs the multiplication operation inherent in the correlation process. A 15 GHz analogue multiplier suitable for such systems is designed and tested and a full noise analysis of multipliers in analogue correlators presented. A further multiplier design in SiGe HBT technology is also presented which offers benefits in the area of low frequency noise. In the effort to process even wider bandwidths, applications of photonics to digitisers and multipliers are investigated. A new architecture for a wide bandwidth photonic multiplier is presented and its noise properties analysed, and the use of photonics to increase the sample rate of digitisers examined.

Thesis (Ph. D.)--Georgia State University, 2006. / Title from title screen. Nikolaus Dietz, committee chair; Brian Thoms, Mark Stockman, Vadym Apalkov, Douglas Gies, committee members. Electronic text (167 p. : ill. (some col.)). Description based on contents viewed Apr. 24, 2007. Includes bibliographical references (p. 162-167).

Thesis (M.S.)--University of Delaware, 2006. / Principal faculty advisor: Robert W. Birkmire, Dept. of Materials Science & Engineering. Includes bibliographical references.

No description available.

Reproduction de : Thèse de doctorat : Physique nucléaire : Lyon 1 : 2005. / Titre provenant de l'écran titre. 133 réf. bibliogr.

Our effort to provide an efficient route to serine glycosides with utility in glycopeptide synthesis has led to the identification of two particularly effective promoters of O-glycosylation. Indium(III) bromide and scandium(III) triflate were shown to be superior promoters of microwave accelerated O-glycosylation utilizing peracetyl carbohydrate donors. 247, 249 These Lewis acids afforded several advantages over previously described promoters including, increased yields, tolerance to moisture, decreased environmental toxicity, ease of work up, and increased reproducibility. Both affected the microwave accelerated glycosylation of Fmoc-ser-OH with sugar peracetates providing superior yields to previously reported methods. For larger scale work the two step route involving the glycosylation of Fmoc-Ser-OBn followed by removal of the benzyl protecting group via hydrogenolysis was preferred. Of the two Lewis acids, the minimally active indium (III) bromide was preferred, as it afforded slightly higher yields and was effective in catalytic quantities. Three groups of helical DAMGO glycopeptide analogs were synthesized in order to provide a better understanding of the structure activity relationships of these opioid peptides. Although the introduction of the amphipathic helix significantly affected binding of the DAMGO message, there was no correlation between binding affinity at the individual opioid receptors and the degree of helicity. In general, addition of the helical address imparted increased affinity for the kappa receptor. The nature of the linker connecting the N-terminal DAMGO sequence and the C-terminal helical address effected binding affinity only slightly. Successive addition of positive charges to the address increased binding at all three opioid receptors until a maximum was reached at a positive two address charge. Although, the amphipathic helix was shown to moderate receptor selectivity, the native mu preference of the DAMGO message was retained Two groups of fluorescent analogs of the mixed δ / μ opioid agonist MD100 were prepared. Within the first series, the fluorescent label was attached to the interior of the address sequence employing the pNZ moiety as a secondary protecting group. The second series of analogs was based on NovaTag™ resin, and allowed for attachment of the fluorophore at the carboxy terminus. The influence on helicity imparted by fluorophore conjugation depended on the nature and point of attachment of the label. The disruption of secondary structure associated with attachment of the fluorescent correlated with decreased binding affinity at the individual opioid receptors. Preliminary in vivo results were encouraging. The least parent like of the MD100 fluorescent analogs was shown to be taken up into endothelial cells. This suggests that the labeled glycopeptides are likely to cross the blood-brain barrier.

No description available.

The thesis describes measurements of the velocity-field characteristic of indium phosphide, below threshold by a direct method and above threshold by domain measurements. Comparisons, with good agreement, are made with microwave measurements, below threshold on material from the same slices, and above threshold on material with very similar properties. A historical description of the Gunn effect and domain theory precedes a description of the structure of indium phosphide and a survey of published velocity-field calculations and measurements, showing the difference between 2- and 3-level conduction band models. A value for the T valley deformation potential has previously been deduced from the temperature variation of low-field mobility by adding reciprocal mobilities due to different scattering processes. This method is examined and experimental results of other workers are shown consistent with a lower deformation potential than supposed. Sub-threshold results agree closely with other, published, measurements, using various techniques. Extended to 77 K, the subthreshold method gave results agreeing reasonably with predictions for this temperature, and very well with extrapolations from other calculated and measured data. Published high-field domain measurements made with a pointcontact probe differ greatly from others. Experiments to produce a point-contact probe and associated differentiator with a known performance, and analysis of a simple circuit model indicate that the specimen resistivity controls the probe response, necessitating different probe resistances for different material resistivities. The probe was still found fundamentally difficult to use and is suspected of causing specimen damage due to localised heating under the point. Domain shapes measured agreed with published measurements from capacitive probes, but domain velocity was higher, giving a higher valley velocity (0.76 - 0.99 x 1O ⁷ cm/s). Comparison of the deduced velocity-field curve with published calculations strongly supports a 2-level transfer mechanism.

In radio astronomy wider observing bandwidths are constantly desired for the reasons of improved sensitivity and velocity coverage. As observing frequencies move steadily higher these needs become even more pressing. In order to process wider bandwidths, components that can perform at higher frequencies are required. The chief limiting component in the area of digital spectrometers and correlators is the digitiser. This is the component that samples and quantises the bandwidth of interest for further digital processing, and must function at a sample rate of at least twice the operating bandwidth. In this work a range of high speed digitiser integrated circuits (IC) are designed using an advanced InP HBT semiconductor process and their performance limits analysed. These digitiser ICs are shown to operate at up to 10 giga-samples/s, significantly faster than existing digitisers, and a complete digitiser system incorporating one of these is designed and tested that operates at up to 4 giga-samples/s, giving 2 GHz bandwidth coverage. The digitisers presented include a novel photonic I/O digitiser which contains an integrated photonic interface and is the first digitiser device reported with integrated photonic connectivity. In the complementary area of analogue correlators the limiting component is the device which performs the multiplication operation inherent in the correlation process. A 15 GHz analogue multiplier suitable for such systems is designed and tested and a full noise analysis of multipliers in analogue correlators presented. A further multiplier design in SiGe HBT technology is also presented which offers benefits in the area of low frequency noise. In the effort to process even wider bandwidths, applications of photonics to digitisers and multipliers are investigated. A new architecture for a wide bandwidth photonic multiplier is presented and its noise properties analysed, and the use of photonics to increase the sample rate of digitisers examined.