by Tsui Wai-kwok Ricky. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 58-59). / Abstracts in English and Chinese. / Chapter 1 --- Preliminary --- p.4 / Chapter 1.1 --- Introduction --- p.4 / Chapter 1.2 --- Some basic theorem --- p.7 / Chapter 2 --- Bubble tree Convergence for a sequence of harmonic map --- p.11 / Chapter 3 --- Heat Flow of Harmonic Maps on Riemann Surface --- p.21 / Chapter 3.1 --- Existence of unique solution to the evolution problem --- p.21 / Chapter 3.1.1 --- Some Basic Estimates --- p.22 / Chapter 3.1.2 --- Existence Result --- p.34 / Chapter 3.1.3 --- Behaviour of solutions near singular points --- p.37 / Chapter 3.2 --- Finite time Blow-up --- p.39 / Chapter 3.3 --- Energy Identity --- p.51 / Bibliography --- p.58

by Sheng Mao. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 49-51). / Abstracts in English and Chinese. / Chapter 1 --- What Is K3 Surface? --- p.2 / Chapter 1.1 --- Algebraic K3 Surface --- p.2 / Chapter 1.1.1 --- Definition and Examples --- p.2 / Chapter 1.1.2 --- Topological Invariants of K3 Surfaces --- p.7 / Chapter 1.2 --- Local Torelli Theorem for K3 surfaces --- p.11 / Chapter 1.3 --- Moduli for polarlized K3 surfaces --- p.17 / Chapter 2 --- Arakelov-Yau Type Inequalities For K3 Surfaces --- p.22 / Chapter 2.1 --- A Short Introduction to Hodge Theory --- p.22 / Chapter 2.1.1 --- Variation of Hodge Structrue --- p.22 / Chapter 2.1.2 --- Degeneration of Variation of Hodge Structure --- p.33 / Chapter 2.2 --- Arakelov-Yau Type Inequalities for Family of K3 Sur- faces Over Curve --- p.40 / Chapter 2.3 --- Application to Rigidity Theorem --- p.44 / Bibliography --- p.49

" We are investigating resolution of chiral drugs via crystallization on self-assembled monolayers functionalized with achiral and chiral molecules that exhibit varying hydrophobicity/hydrophilicity as a means to bring about enantioseparation. Two goals of this work are to determine (1) whether chiral surfaces can act as templates that bias molecular aggregation at the surface to favor single enantiomers thereby inducing nucleation of conglomerates over racemic crystals, and (2) whether chiral templating can be used to induce selective nucleation of one enantiomer leading to high enantiomeric excess. Racemic compounds being investigated include the antibiotic 3-phenyllactic acid(3PLA) and the muscle-tissue repairing amino acid N-acetylleucine(NAL). Achiral and chiral alkanethiols were self-assembled onto 2D gold substrates by overnight immersion of the gold slides in ethanolic solution of the alkanethiols. The functional groups deposited on the SAM were characterized by grazing incidence IR spectroscopy, contact angle goniometry and ellipsometry. The contact angle and ellipsometry measurements showed that the cysteine SAMs form a bilayer consisting of monolayers of cysteine covalently bonded to gold covered by an overlayer of cysteine. The approach of using chiral templates to induce enantioselective nucleation of racemic drugs on the chiral surface via crystallization was first demonstrated for 3-phenyllactic(3PLA). Homochiral crystals (1), and conglomerates (3) formed from aqueous solution as needles, whereas heterochiral racemic crystals (2) formed from 3:1 hexanes-ethyl acetate as rectangular blocks. A comparison of the thermal stability of the three crystalline forms showed that the crystals of 1 and 3 exhibit greater thermal stability than crystals of 2 such that the racemic form does not appear in the phase diagram. We showed that chiral SAMs of cysteine were able to resolve enantiomers of racemic 3PLA effectively with up to 30% enantiomeric excess in bulk samples of crystals, and that the enantiomer in excess could be controlled based on the choice of D- or L-cysteine as the chiral template. Moreover, crystals of D- or L-3PLA grew oriented with a high degree of selectivity for attachment on the (004) face. We show that the presence of the excess enantiomer (D- or L-3PLA) present in solution acts as an additive to cause a change in the habit of L- or D-3PLA on L- or D-cysteine SAM. We also demonstrated the enantioselective crystallization on chiral SAMs for N-acetylleucine (NAL) which gave a higher enantiomeric enrichment with upto 80% ee. A novel approach of using chiral drugs as templates to amplify the chirality for better self-recognition was designed and SAMs were formed from cysteamine with an overlayer of L-3PLA. As a proof of concept, crystallization of racemic 3PLA on L-3PLA/cysteamine SAMs gave 24% enantiomeric enrichment and our results are comparable to cysteine SAMs. These results confirm our hypothesis that the molecular aggregation on D- and L-cysteine occurs via specific diastereomeric hydrogen-bonding interactions that discriminate between the two enantiomers, thereby promoting enantioselective nucleation and facial selectivity of chiral drugs. "

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Lau, Sui Ki. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 81). / Abstract also in Chinese. / Chapter 1 --- Basic Notions of Riemann Surfaces --- p.5 / Chapter 1.1 --- "Functions, Forms and Hurwitz's Formula" --- p.6 / Chapter 1.2 --- Divisors --- p.10 / Chapter 1.3 --- Plucker's Formula for a Smooth Projective Plane Curve --- p.14 / Chapter 1.4 --- Sheaves and Cohomology --- p.17 / Chapter 2 --- The Riemann-Roch Theorem and Algebraic Curves --- p.27 / Chapter 2.1 --- Finiteness Theorem --- p.27 / Chapter 2.2 --- Transcendence Degree of M(X) --- p.33 / Chapter 2.3 --- The Riemann-Roch Theorem and Serre Duality --- p.37 / Chapter 2.4 --- Holomorphic Embedding in a Projective Space --- p.44 / Chapter 2.5 --- Algebraic Curves --- p.50 / Chapter 3 --- Invertible Sheaves and Line Bundles --- p.55 / Chapter 3.1 --- Algebraic Sheaves --- p.55 / Chapter 3.2 --- Invertible Sheaves --- p.55 / Chapter 3.3 --- Line Bundles --- p.61 / Chapter 3.4 --- Isomorphic Representations of the Picard Group --- p.66 / Chapter 4 --- A Uniqueness Theorem for Algebraic Curves --- p.72 / Chapter 4.1 --- Associated Curves and Normal Forms --- p.72 / Chapter 4.2 --- Proof of a Uniqueness Theorem for Algebraic Curves --- p.76 / Bibliography --- p.81

Sur une surface superhydrophobe, les gouttes d'eau rebondissent ou roulent grâce au piégeage de poches d'air entre les microstructures (état « Fakir »). Cependant, cette même surface est inefficace vis à vis d'une goutte d'alcool qui s'imprègne dans les aspérités. Afin d'étendre l'effet superhydrophobe à une large gamme de liquides, il est nécessaire de fabriquer des microstructures présentant une géométrie dite « ré-entrante ». Ces surfaces sont alors dites superomniphobes. Dans un premier temps, nous présentons deux procédés de fabrication permettant d'obtenir de telles surfaces à base de polymère, ou à base de polymère et de nitrure de silicium. Dans un second temps, nous étudions les propriétés d'adhésion (hystérésis d’angle de contact) de ces surfaces en fonction des paramètres géométriques des microstructures. Les résultats mettent en évidence un effet de saturation non décrit par les modèles théoriques existants. Afin de contribuer à la compréhension des mécanismes physiques responsables de ce phénomène, nous présentons une expérience permettant d'imager la déformation de l'interface liquide sur ces surfaces. Les mesures montrent la formation de micro ponts liquides durant le démouillage. Nous montrons que l'analyse des modes d'instabilité de ces ponts liquides permet de justifier qualitativement la saturation observée. Ces expériences mettent également en évidence le dépôt de nano-volumes de liquide sur les structures suite au démouillage de la surface. L'hétérogénéité de ces dépôts est corrélée à la dynamique de la ligne triple. Ce phénomène présente des perspectives intéressantes pour le dépôt contrôlé et passif de colloïdes ou biomatériaux. / On a superhydrophobic surface, water drops rebound and roll off due to trapping of air pockets between micro or nano structures (“Fakir” state). However, the same surface is inefficient toward alcohol drops which spread in the asperities.In order to extend the superhydrophobic effect to a wide range of liquids, it is necessary to design microstuctures with a “re-entrant” geometry. These surfaces are then called superomniphobic. In a first time, we present two microfabrication processes enabling to obtain such surfaces in polymer, or in polymer and silicon nitride. In a second time, we study the adhesion properties (contact angle hysteresis) as a function of microstructures geometrical parameters. The results point out a saturation effect which is not described by actual models. In order to better understand the underlying physical mechanisms responsible for this phenomenon, we present an experiment enabling to visualize the liquid interface deformation on these surfaces. Measurements show that dewetting occurs through the formation of micro capillary bridges. By analyzing the instability modes of these liquid bridges, we show that it is possible to qualitatively demonstrate the observed saturation effect. The experiments also point out the presence of nano-scale liquid volumes on the micro-structures resulting from de-wetting of the surface. The heterogeneities of these deposits is correlated to the triple line dynamic. The phenomenon presents interesting perspectives for the controlled and passive deposition of colloids or bio-materials.

Ces travaux de thèse ont porté sur l’étude de solutions originales pour limiter la biopollution dans des systèmes microfluidiques à base d'électromouillage (EWOD) couplés à un biocapteur à résonance de plasmons de surface (SPR). Deux approches complémentaires ont été étudiées. Dans un premier temps nous avons mis à profit la forte adsorption de protéines sur des nanofeuillets d'oxyde de graphène (GO): les caractérisations de mouillage de solutions contenant un mélange de GO et de protéines (albumine sérique bovine - BSA) ont permis de montrer que le GO maintenait en suspension les protéines en évitant leur adsorption sur la surface. Le résultat le plus remarquable obtenu concerne le déplacement par EWOD de BSA, à une concentration de 195ng/µL (pour 500ng/µL de GO), 30 fois plus que ce qu’il est possible de transporter sans GO. Nous avons montré que la présence des feuillets de GO n’altère pas l’activité enzymatique. Une autre solution a consisté à développer des surfaces superomniphobes (connues pour leur propriété d’auto-nettoyage) via un dépôt chimique de nanostructures d’oxyde de zinc (ZnO). Nous avons montré que certaines nanostructures de forme réentrante présentent des angles de contact supérieurs à 140°, des hystérésis inférieures à 20° pour des liquides de tensions de surface supérieures à 35mN/m. Pour finir, ces deux approches ont été validées pour l’application envisagée. L’interaction entre biomolécules et biodétecteur SPR a pu être validée (i) en contrôlant la désorption des protéines du GO par une solution basique, (ii) en réalisant des ouvertures dans les nanostructures de ZnO. / This work reports on the study of original strategies to limit biofouling in Electrowetting-on-Dielectric (EWOD) based microfluidic devices coupled with a Surface Plasmon Resonance (SPR) biosensor. Two complementary approaches have been investigated. In the first part, we take advantage of the high adsorption capacity of graphene oxide (GO) for biomolecules: the wetting properties of a mixed solution containing Bovin Serum Albumine (BSA) and GO show that GO keeps proteins in suspension inhibiting their adsorption on the surface. The most important result concerns the EWOD motion of BSA droplet with a concentration of 195ng/µL (with 500ng/µL of GO). In this case, the BSA concentration is 30 times higher than the BSA concentration which can be displaced without GO. We show also that the presence of GO in the droplet does not alter the enzymatic activity of horseradish peroxidase (HRP) after GO/HRP displacement. The other developed solution consists in the development of superomniphobic surfaces (known for their self-cleaning properties) via chemical deposition of zinc oxide (ZnO) nanostructures. The chemically functionalized ZnO nanostructures display contact angles higher than 140° and hysteresis lower than 20° for liquids of surface tensions higher than 35 mN/m. To conclude, these two approaches have been validated for the targeted application. Interaction between biomolecules and the SPR biosensor can be realized (i) by controlling proteins’ desorption from GO in base solution, (ii) by making microapertures in ZnO nanostructured surfaces.

No description available.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 29, 2007) Includes bibliographical references (p. 92-94).

Graduation date: 1996