Thin films of alumina were deposited on ferrite (NiₓZn₍₁₋ₓ₎Fe₂O₄), glass, single crystal silicon and graphite substrates by RF sputtering. Though standard, amorphous Al₂O₃ films are readily soluble in hot phosphoric acid, these sputtered films exhibited only reluctant etchability by the acid. Experiments were initially performed to understand the parameters in the sputtering process which were influential in the formation of unetchable films. The results showed that a high concentration of water vapor or oxygen molecules in the sputtering chamber during deposition was the most significant variable controlling the growth of unetchable films. The films were categorized according to their degree of solubility in H₃PO₄ and were examined using various microanalytical characterization techniques. TEM analysis directly showed the existence of crystalline γ-Al₂O₃ in the film at the film-substrate interface. The γ-Al₂O₃ phase grew with a preferred orientation coincident with the substrate orientation--as in heteroepitaxial growth. The occurrence of this film phase was related to the oxygen partial pressure, the substrate material, and the substrate temperature and was believed to be the cause of the film's incomplete etching behavior.

Various metal phthalocyanines have been used as dyes, catalysts, indicators, electrophotographic receptors and more recently as active elements in chemical sensors and photoconductive materials for solar energy conversion applications. Of the MPc's, VOPc, GaPc-Cl and TiOPc have shown promise for solar energy conversion devices. GaPc-Cl has also shown promise as a chemical sensor. Up to this point in time, the focus of Pc research in this group has been in the direction of characterizing the photoelectrochemical properties of these materials. Recently, solid state studies of TiOPc have been done to determine the electronic properties of a tetravalent metal Pc, such as conductivity and photoconductivity. Such solid state measurements are facilitated by the use of interdigitated microelectrode arrays which are coated with thin films of various Pc's.

A study has been carried out to investigate the effects of heat treatment on microindentation hardness, abrasion and corrosion resistance of Electroless Nickel coatings. In particular, a proprietary coating system, NIKLAD 794 has been investigated. Samples of 4130 steel have been plated according to manufacturer's specifications. The plated samples have then been subjected to an array of heat treatment temperatures and times. Post heat treatment tests have been conducted including Taber Abrasion testing, salt fog chamber testing, and Knoop microindentation hardness testing. Results of the individual tests have been compared to determine the effects of heat treatment on, and the interactions between, the parameters examined.

Cubic boron nitride (cBN) thin films offer attractive mechanical and electrical properties. The synthesis of cBN films have been deposited using both physical and chemical vapor deposition methods, which generate internal residual, stresses that result in delamination of the film from substrates. Boron nitride films were deposited using electron beam evaporation without bias voltage and nitrogen bombardment (to reduce stresses) were characterize using FTIR, XRD, SEM, EDS, TEM, and AFM techniques. In addition, a pin-on-disk tribological test was used to measure coefficient of friction. Results indicated that samples deposited at 400°C contained higher cubic phase of BN compared to those films deposited at room temperature. A BN film containing cubic phase deposited at 400°C for 2 hours showed 0.1 friction coefficient.

A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Master of Science in Engineering, 2017 / This research has considered an idealistic non-interleaved planar transformer wherein only the electromagnetic parasitic capacitive and inductive elements arising out of the transformer geometry are taken into account, without considering material limitations. A suitable model for the planar transformer is used to analyse its frequency and power transfer characteristics; this model was validated by three dimensional electromagnetic simulations of various planar transformer structures in FEKO simulation software. The capacitive and inductive parasitics in this model have been found to be functions of the dielectric thickness. The theoretical bandwidth for the planar transformer is defined in this research as a function of dielectric thickness. The effect of dielectric thickness of the transformer windings on the bandwidth of the transformer is analysed, based on the premise that the inherent parasitic capacitive and inductive elements would affect the transfer characteristics of the transformer. Upon conclusion of this analysis, it is found that the dielectric thickness of a planar transformer can be optimised such as to present an optimised bandwidth. A closed form analytic expression for the optimum dielectric thickness value is derived and presented in this research. In a design example of a 4:1 50W transformer presented in this research, it has been shown that the bandwidth can be improved by 384%, along with a power density improvement of 45%, upon choosing of an optimum dielectric thickness of 0.156mm to replace a standard 0.4mm thick dielectric. It should be noted that the results derived in this research are purely theoretical, justified by many idealisations and assumptions that are argued throughout the research. It is thus expected that practical results should at best approach the theoretical results, due to the known non-ideal nature of reality. / CK2018

by Ong Chung Wo. / Title also in Chinese. / Thesis (Ph.D.)--Chinese University of Hong Kong. / Bibliography: leaves 258-263. / Acknowledgements / Abstract / Table of Contents / Chapter Chapter 1 --- Introduction --- p.1 / Chapter Chapter 2 --- Sample Preparation --- p.6 / Chapter A. --- General Review of Chemical Vapour Deposition Technique --- p.6 / Chapter B. --- Our Deposition System --- p.9 / Chapter B.1 --- General Description --- p.9 / Chapter B.2 --- Induction Heater --- p.10 / Chapter B.3 --- Graphite Susceptor --- p.12 / Chapter B.4 --- Safety --- p.13 / Chapter C. --- Sample Description --- p.16 / Chapter Chapter 3 --- Thickness Measurement --- p.26 / Chapter Chapter 4 --- Composition Analysis --- p.29 / Chapter A. --- Introduction --- p.29 / Chapter B. --- Composition Analysis of Boron-Silicon Films Using EDX --- p.32 / Chapter B.1 --- Experimental Method --- p.32 / Chapter B.2 --- Requirement on Film Thickness and Preparation of Unsupported Films --- p.33 / Chapter B.3 --- Possible Applications and Limitations of Our Method --- p.35 / Chapter B.4 --- Results --- p.35 / Chapter Chapter 5 --- X-ray Diffraction Experiment --- p.42 / Chapter A. --- Introduction --- p.42 / Chapter B. --- Structures of Boron and Silicon-Boron Compounds --- p.43 / Chapter B.1 --- B12 Icosahedron and Three-Center Two-Electron Bond --- p.43 / Chapter B.2 --- Polymorphism of Crystalline Boron --- p.44 / Chapter B.2.1 --- α-Rhombohedral Boron --- p.44 / Chapter B.2.2 --- β-Rhombohedral Boron --- p.45 / Chapter B.2.3 --- Amorphous Boron --- p.47 / Chapter B.3 --- Structures of Crystalline Boron-Silicon Compounds --- p.48 / Chapter C. --- X-ray Diffraction Experiment --- p.50 / Chapter C.1 --- Experimental Technique --- p.50 / Chapter C.2 --- Analysis of X-Ray Diffraction Pattern --- p.50 / Chapter D. --- Results and Discussion --- p.51 / Chapter D.1 --- Boron Films --- p.51 / Chapter D.2 --- Boron-Silicon Films --- p.57 / Chapter Chapter 6 --- Infrared Absorption Experiment --- p.84 / Chapter A. --- Experimental Method --- p.84 / Chapter B. --- Results --- p.87 / Chapter C. --- Discussion --- p.88 / Chapter C.1 --- Analysis of Boron Films --- p.88 / Chapter C.1.1 --- Indentification of Three Absorption Bands --- p.88 / Chapter C.1.2 --- Effect of Substrate Temperature --- p.91 / Chapter C.2 --- Analysis of Boron-Silicon Films --- p.92 / Chapter C.2.1 --- Effect of Substrate Temperature --- p.92 / Chapter C.2.2 --- Effect of Silicon Incorporation --- p.93 / Chapter C.2.3 --- Existence of Icosahedral Clusters --- p.94 / Chapter C.3 --- Comparative Study of Deposition Mechanism Between Thermal CVD Method and Glow Discharge Method --- p.94 / Chapter Chapter 7 --- Microhardness and Surface Morphology --- p.111 / Chapter A. --- Measuring Techniques --- p.111 / Chapter B. --- Microhardness Measurement --- p.113 / Chapter B.1 --- Boron Films --- p.113 / Chapter B.2 --- Boron-Silicon Films --- p.114 / Chapter C. --- Surface Morphology --- p.114 / Chapter C.1 --- Boron Films --- p.114 / Chapter C.2 --- Boron-Silicon Films --- p.115 / Chapter Chapter 8 --- Optical Absorption Experiment --- p.127 / Chapter A. --- Introduction --- p.127 / Chapter B. --- Theory of Optical Absorption --- p.128 / Chapter B.1 --- Absorption of Crystalline Materials --- p.129 / Chapter B.2 --- Optical Absorption of Amorphous Materials --- p.132 / Chapter C. --- Results --- p.135 / Chapter C.1 --- Boron Films --- p.135 / Chapter C.2 --- Boron-Silicon Films --- p.136 / Chapter D. --- Analysis --- p.138 / Chapter D.1 --- Band Models --- p.138 / Chapter D.2 --- Deconvolution of Absorption Spectra --- p.140 / Chapter D.2.1 --- Deconvolution of Absorption Spectra of Boron Films --- p.141 / Chapter D.2.2 --- Deconvolution of Absorption Spectra of Boron-Silicon Films --- p.144 / Chapter D.2.3 --- Results --- p.146 / Chapter E. --- Discussion --- p.149 / Chapter Chapter 9 --- Conductivity and Thermoelectric Power Measurements --- p.203 / Chapter A. --- Transport Mechanism in Amorphous Semiconductors --- p.203 / Chapter A.1 --- Band Models of Amorphous Semiconductors --- p.203 / Chapter A.2 --- Electrical Conductivity and Thermoelectric Power --- p.205 / Chapter B. --- Experimental Methods --- p.208 / Chapter C. --- Results --- p.209 / Chapter C.1 --- Boron Films --- p.209 / Chapter C.2 --- Boron-Silicon Films --- p.210 / Chapter D. --- Discussion --- p.212 / Chapter D.1 --- Boron Films --- p.212 / Chapter D.2 --- Boron-Silicon Films --- p.213 / Chapter Chapter 10 --- Electron Spin Resonance --- p.230 / Chapter A. --- Introduction --- p.230 / Chapter B. --- Experimental Method --- p.231 / Chapter C. --- Results --- p.231 / Chapter C.1 --- Boron Films --- p.231 / Chapter C.2 --- Boron-Silicon Deposited at 300°C --- p.232 / Chapter C.3 --- Boron-Silicon Deposited at 460 and 620°C --- p.233 / Chapter D. --- Discussion --- p.235 / Chapter D.1 --- Boron Films --- p.235 / Chapter D.2 --- Boron-Silicon Films --- p.237 / Chapter Chapter 11 --- Conclusion --- p.254 / Chapter A. --- Structure --- p.254 / Chapter B. --- Mechanical Properties --- p.256 / Chapter C. --- Optical Absorption and Density of States --- p.256 / Chapter D. --- Electrical Properties --- p.257 / References --- p.258

by Kwong-hung Tam = 低壓化學氣相沈積硅膜之電學特性 / 譚廣雄. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1985 / Bibliography: leaves 102-105. / by Kwong-hung Tam = Di ya hua xue qi xiang chen ji gui mo zhi dian xue te xing / Tan Guangxiong.

張詠思. / "2012年1月". / "2012 nian 1 yue". / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 144-152). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in Chinese and English. / Zhang Yongsi.

Ce travail décrit la séparation de microphase à l'état solide d'un copolymère dibloc comprenant un bloc hautement biocompatible poly [2 - (méthacryloyloxy) éthyl phosphorylcholine] et un bloc pH-sensible poly [2 - (diisopropylamino) méthacrylate d'éthyle] (PMPC-b-PDPA). L'auto-assemblage d'un copolymère dibloc amphiphiles à base de polystyrène (PS) et le poly (acide acrylique) (PAA), a été étudié en suspension aqueuse, et leur décoration par du chitosane, afin de vérifier leur capacité à encapsuler et à libérer par voie transdermique la finastéride, une molécule stéroïdiens inhibiteur de la enzyme 5-alpha-réductase, qui a été recommandée pour le traitement de l'alopécie androgénétique. La morphologie des films PMPC30-b-PDPA60 a été analysée par SAXS et (S) TEM. Films du PMPC30-b-PDPA60 préparés dans une solution de l'éthanol à température ambiante présentent une morphologie cylindrique, qui subit une transition ordre-ordre sur un recuit thermique à 170 ° C: la structure lamellaire résultant coexiste avec une proportion de cylindres organisée dans une phase hexagonale compacte. En revanche, les films du copolymère préparé à partir de méthanol ne subissent pas la même transition morphologique, résultant dans des structures mal organisées, indépendante de traitement thermique. Enfin, les structures lamellaires sont obtenues directement à partir d'une solution aqueuse à pH 4, sans traitement thermique. Ces systèmes offrent une nouvelle alternative pour la fabrication de structures lamellaires constituées d'un matériau biomimétique et anti-fouling, élargissant l'éventail des possibilités dans le domaine de l'ingénierie macromoléculaire.Une autre stratégie adoptée dans ce travail a été basé sur le développement de nanoparticules bien organisé avec des propriétés de surface nature bioinspirés, formé entre polymersomes chargés négativement à base des copolymères à blocs de polystyrène (PS) et le poly (acide acrylique) (PAA) décorés avec du chitosane, un polysaccharide de charge opposée. Le rôle de l'adsorption du chitosane avec deux poids moléculaires distincts (chitosane oligosaccharides et du chitosane avec un faible poids moléculaire) sur la surface des nanoparticules PS139-b-PAA17 et des nanoparticules PS404-b-PAA63 ont été démontrés par diffusion dynamique de la lumière, potentiel zêta et caractérisation morphologiques. En présence du chitosane, le potentiel zêta de polymersomes devient positif. Ce résultat a été interprété en termes d'interactions électrostatiques, qui induisent une adsorption du chitosane sur la surface des polymersomes. Ce résultat a été confirmé par une observation comparative par microscopie entre des polymersomes et des polymersomes décorées. Polymersomes avec un diamètre <200 nm et une distribution granulométrique relativement étroite ont été obtenus pour les deux systèmes. L'effet de la décoration des nanoparticules par du chitosane sur la perméation cutanée in vitro du finastéride, incorporé dans la paroi hydrophobe de polymersomes, a également été évaluée. La pénétration cutanée du finastéride a été estimée par les paramètres de perméabilité tels que le flux, temps de latence et du coefficient de perméabilité de la finastéride. Une amélioration de la perméation du finastéride à partir des nanoparticules a été observée, en particulier à partir de nanoparticules décorées avec du chitosane. Le polymersome PS404-b-PAA63 décorées avec du chitosane semble être le système le plus approprié car il favorisé une meilleure rétention du médicament dans la peau et les faibles valeurs de flux de perméation, suggérant que le système fournit un véhicule de remplacement pour l'administration transdermique de finastéride. / This work describes the microphase separation in bulk of an diblock copolymer comprising a highly biocompatible poly[2-(methacryloyloxy)ethyl phosphorylcholine] block and a pH-sensitive poly[2-(diisopropylamino) ethyl methacrylate] block (PMPC-b-PDPA). The self-assembly of an amphiphilic diblock copolymer based on polystyrene (PS) and poly(acrylic acid) (PAA) was studied in terms of their decoration with the chitosan, verifying their ability to incorporate and transdermally release the drug finasteride, a steroidal molecule 5-alpha-reductase inhibitor that has been recommended for the treatment of androgenetic alopecia. The morphology of PMPC30-b-PDPA60 films was analyzed using SAXS and (S)TEM. PMPC30-b-PDPA60 films cast from ethanol solution at room temperature exhibit a thermodynamically quasi-stable cylindrical morphology, which undergoes an order-order transition upon thermal annealing at 170 oC: the resulting lamellar structure coexists with a minor proportion of cylinders organized into a hexagonal compact phase. In contrast, copolymer films cast from methanol do not undergo the same morphological transition. Instead, short-range liquid-like structures are obtained regardless of the annealing processes. Finally, direct self-assembly to form a lamellar morphology at room temperature can be achieved by solvent-casting from aqueous solution at pH 4. These systems offer a new alternative for the fabrication of lamellar structures in which one layer is biomimetic and non-fouling, expanding the range of possibilities in the macromolecular engineering field. Another strategy adopted in this work was based on the development of well-organized nanoparticles with nature-bioinspired surface properties, formed between negatively charged polymersomes based on polystyrene (PS) and poly(acrylic acid) (PAA) block copolymers decorated with chitosan, an oppositely charged polysaccharide. The role of chitosan with two distinct molecular weights (chitosan oligosaccharide and low molecular weight chitosan) adsorption on the surface of oppositely charged PS139-b-PAA17 and PS404-b-PAA63 nanoparticles were demonstrated by dynamic light scattering measurements, zeta potential and morphological characterization. In the presence of chitosan, the zeta potential of polymersomes becomes positive. This result was interpreted in terms of electrostatic interactions, which induce a flat adsorption of the chitosan on the surface of the polymersomes. This result was further confirmed by a comparative observation by microscopy of bare and chitosan-decorated polymersomes. Polymersomes with a diameter < 200 nm and a relatively narrow size distribution were obtained for both systems. The effect of chitosan decoration of self-assembled nanoparticles on skin penetration in vitro of finasteride was also evaluated, once incorporated in the wall hydrophobic of polymersomes. The skin permeation through pig ear skin of finasteride was estimated by the permeability parameters such as flux, lag time and permeability coefficient of finasteride. An improved permeation of finasteride from the nanoparticle system was observed, especially from nanoparticles decorated with chitosan. The PS404-b-PAA63 polymersome decorated with chitosan seems to be the most appropriate system since it provided higher drug retention in skin and low permeation flux values, suggesting that the PS-b-PAA/chitosan system provides an alternative for transdermal drug delivery system of finasteride.

by Hui Koon-chung = 由電子束照射引起氧化金屬膜覆蓋的氧化鋅之光學特性 / 許冠中. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2004. / Includes bibliographical references (leaves 87-89). / Text in English; abstracts in English and Chinese. / by Hui Koon-chung = You dian zi shu zhao she yin qi yang hua jin shu mo fu gai de yang hua xin zhi guang xue te xing / Xu Guanzhong. / ABSTRACT --- p.i / ACKNOWLEDGMENTS --- p.iii / TABLE OF CONTENTS --- p.iv / LIST OF FIGURES --- p.vi / LIST OF TABLES --- p.x / Chapter 1. --- Introduction --- p.1 / Chapter 1.1 --- Motivation --- p.1 / Chapter 1.2 --- Overview of ZnO / Chapter 1.3 --- Overview of the Thesis / Chapter 2. --- Experimental conditions and procedures --- p.11 / Chapter 2.1 --- Samples preparation / Chapter 2.2 --- Optical and electrical Characterizations of ZnO / Chapter 2.2.1 --- Setup of cathodoluminescence (CL) spectroscopy / Chapter 2.2.2 --- Setup of photoluminescence (PL) spectroscopy / Chapter 2.2.3 --- Setup of photoconductivity measurement / Chapter 2.2.4 --- Setup of atomic force microscopy AFM / Chapter 2.2.5 --- X-ray photoelectron spectroscopy (XPS) / Chapter 3. --- Experimental results and data analysis --- p.21 / Chapter 3.1 --- The luminescence of ZnO --- p.21 / Chapter 3.2 --- Effects of metal capped layer in luminescence --- p.24 / Chapter 3.3 --- Optical memory effect of A1 capped ZnO --- p.28 / Chapter 3.4 --- The XPS study ofAl capped ZnO --- p.33 / Chapter 3.5 --- Optical properties and photoconductivity studies of AlOx-capped ZnO --- p.35 / Chapter 3.6 --- Time- and Electron-dose dependent CL of AlOx capped ZnO --- p.41 / Chapter 3.7 --- Dependence of band-edge enhancement on Deep Level to band-edge emission ratio --- p.53 / Chapter 3.8 --- Temperature-dependent CL of AlOx capped ZnO --- p.56 / Chapter 3.9 --- Electrical measurement of luminescence enhanced ZnO --- p.64 / Chapter 4. --- Discussion --- p.69 / Chapter 4.1 --- General discussion --- p.69 / Chapter 4.2 --- The effect of AlOx capping on the optical properties of ZnO --- p.70 / Chapter 4.3 --- The action of e-beam irradiation on the enhancement of band-edge emission --- p.73 / Chapter 4.4 --- The function of AlOx layer when under electron irradiation --- p.83 / Chapter 5. --- Conclusions --- p.85 / Reference --- p.87