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Wong Chun Ho. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2006. / Includes bibliographical references (leaves 72-77). / Abstracts in English and Chinese. / Contents --- p.i / Acknowledgments --- p.iii / Abstract --- p.iv / Abbreviations and acronyms --- p.vi / Publications originated from the work of this thesis --- p.viii / Chapter Chapter 1 - --- Dendritic Macromolecules and Dendronized Polymers / Chapter 1.1 --- Introduction to Dendrimers and Dendronized Polymers --- p.1 / Chapter 1.2 --- Overview of the Synthesis of Dendronized Polymers --- p.4 / Chapter 1.2.1 --- Graft-from Approach --- p.4 / Chapter 1.2.2 --- Graft-to Approach --- p.5 / Chapter 1.2.3 --- Macromonomer Approach --- p.6 / Chapter 1.2.3.1 --- Step Growth Polymerization --- p.6 / Chapter 1.2.3.2 --- Chain Growth Polymerization --- p.8 / Chapter 1.2.3.3 --- Supramolecular Polymerization --- p.9 / Chapter Chapter 2 - --- En Route to Hydrogen Bond-Mediated. Supramolecular Dendronized Polymers / Chapter 2.1 --- Design of Supramolecular Dendronized Polymers --- p.15 / Chapter 2.1.1 --- Binding Modes in Supramolecular Polymers --- p.15 / Chapter 2.1.1.1 --- Hetero-Complementary Polymerization --- p.16 / Chapter 2.1.1.2 --- Self-Complementary Polymerization --- p.17 / Chapter 2.1.2 --- The Effect of Binding Constant on the Degrees of Polymerization --- p.18 / Chapter 2.1.3 --- The Effect of Dimerization Constant on the Molecular Weight Distribution --- p.21 / Chapter 2.1.4 --- The Dendritic Effect on the UPy Binding Behavior --- p.21 / Chapter 2.2 --- Summary --- p.24 / Chapter Chapter 3 - --- "Design, Synthesis, and Structural Characterization of Dendronized Dimers" / Chapter 3.1 --- Design of Dendronized Dimers --- p.25 / Chapter 3.1.1 --- The Nature of R and R on the Dimerization Behavior --- p.25 / Chapter 3.1.2 --- Selection of Dendrons --- p.26 / Chapter 3.1.3 --- Positioning of Dendrons and the Synthetic Feasibility --- p.27 / Chapter 3.2 --- Synthesis of Dendronized Dimers --- p.28 / Chapter 3.3 --- Characterizations of the Intermediates and Target Dimers --- p.31 / Chapter 3.3.1 --- 1H NMR Spectroscopy --- p.31 / Chapter 3.3.2 --- 13C NMR Spectroscopy --- p.38 / Chapter 3.3.3 --- Mass Spectrometry --- p.41 / Chapter 3.3.4 --- Vapor Pressure Osmometry --- p.43 / Chapter 3.3.5 --- Infrared Spectroscopy --- p.43 / Chapter 3.3.6 --- Gel Permeation Chromatography --- p.44 / Chapter 3.4 --- Conclusions --- p.46 / Chapter Chapter 4 - --- Determination of Dimerization Constants / Chapter 4.1 --- Overview of the Self-Assembling Process in UPy System --- p.47 / Chapter 4.2 --- Determination of the Dimerization Constants (Kdim*) --- p.49 / Chapter 4.2.1 --- Dimerization Constants in CDCl3 at 25 °C --- p.50 / Chapter 4.2.2 --- Dimerization Constants in 10% (v/v) DMSO-d6/CDCl3 at 25 °C --- p.53 / Chapter 4.2.3 --- Dimerization Constants in CDCl3 at 50 °C --- p.56 / Chapter 4.3 --- Heterodimerization Experiment --- p.56 / Chapter 4.4 --- Conclusions --- p.57 / Chapter Chapter 5 - --- Experimental Procedures / Chapter 5.1 --- General Information --- p.60 / Chapter 5.2 --- General Synthetic Procedures --- p.61 / Chapter 5.3 --- Experimental Procedures --- p.62 / References --- p.72 / Appendix / NMR Spectra --- p.78 / GPC results --- p.119

本论文主要研究了红磷作为可见光光催化剂在光解水产生氢气方面的应用。所涉及到的催化剂有：纯红磷，万寿菊状的P/YPO₄中空微米球，以及CoP₂修饰的红磷。论文也会讨论WO₃/TiO₂微米六方片及微米棒的制备，并介绍这些新材料在光解水产生氧气方面的应用。 / 第一章：发现了红磷作为可见光光催化材料在光解水制氢气领域的应用。从羟基自由基的检测和光电响应的测量表明，红磷具有在光照下产生电子和空穴的性质。同时，光生电子还原水的能力亦通过理论计算所验证。此外，半导体性质测试表明红磷具有p型半导体的性质。 / 第二章：通过红磷与YCl₃水溶液的反应，合成了万寿菊状的P/YPO₄中空微米球。所得到的微米球由结晶YPO₄纳米片和无定形红磷组成。光解水产生氢气表明，含有53 wt % YPO₄的P/YPO₄的光催化活性是红磷的6倍。同时，文中进一步讨论了中空微米球的形成机理及其光催化活性提高的原因。 / 第三章：研究并证明了CoP₂可以作为红磷光解水产生氢气的共催化剂。CoP₂的修饰可以极大的提高红磷的光解水产氢效率。其中，含2 wt % CoP₂的CoP₂/P的光解水产生氢气的速率较红磷提高了75倍。而且，CoP₂作为共催化剂的效率优于传统贵金属共催化剂Pt。关于CoP₂的共催化机理，初步认为与Co离子的配位作用有关。 / 第四章：通过简单的沉淀、煅烧反应，制备了由WO₃和 TiO₂纳米颗粒组装而成的WO₃/TiO₂微米棒和微米片。可见光氧化水产生氧气测试表明， WO₃/TiO₂复合物的光催化活性为WO₃的2.5倍以上。提出利用“颗粒堆积模型来解释WO₃/TiO₂ 微米棒和微米片的形成机理。 / 第五章：发现了WO₃对甲基蓝染料有趣的吸附性质。首先，利用钨酸铵，四丙基氢氧化铵和氯化钾合成了WO₃纳米棒。所制备的WO₃表现出了对甲基蓝很强的快速吸附能力。而且，WO₃在5s内所吸附的甲基蓝的量与活性炭在30分钟内的吸附相当。此外，通过离子间的作用力和“印迹-吸附过程对WO₃吸附甲基蓝的特性进行了解释。 / This thesis focuses primarily on the development of red phosphorus based visible-light-driven photocatalysts for hydrogen production from water. These materials include pure red phosphorus, hierarchical P/YPO₄ hollow microspheres, and CoP₂ loaded red phosphors. The fabrication of WO₃/TiO₂ microrods and plates with enhanced photocatalytic water oxidation property is also discussed. / Chapter I:Red phosphorus was discovered as a new visible-light driven photocatalyst for H₂ formation from the reduction of water by photogenerated electrons. The detection of hydroxyl radicals and results from photoconductivity measurements confirmed the photogeneration of electrons from the red phosphorus. Theoretical calculations indicated that the reduction of water by photogenerated electrons would be energetically possible. Moreover, a P-type semiconductor behavior of red phosphorus was observed. / Chapter II:Hierarchical P/YPO₄ hollow microspheres with enhanced photocatalytic activity than the individual components for hydrogen formation were prepared. The composite was synthesized by the reaction from amorphous red P and YCl₃ aqueous solution via a hydrothermal method. The final product consisted of crystalline YPO₄ nanosheets and amorphous red phosphorus. The composite with 53 wt % YPO₄ was up to 6 times more active than red phosphorus under visible light irradiation. The formation mechanism of hierarchical microspheres and the enhanced photocatalytic activity were discussed. / Chapter III:CoP₂ loaded as a cocatalyst significantly enhanced the rate of H2₂ formation from water over red phosphorus under visible light irradiation. The rate of H₂ formation over red P was increased by up to 75 times when loaded with 2 wt % CoP₂. The performance of CoP₂ as a cocatalyst was even higher than that of Pt. The coordination effect of Co ions was proposed to explain the enhanced photocatalytic activity by CoP₂ loaded. / Appendix I:WO₃/TiO₂ microrods and microplates assembled from WO₃ and TiO₂ nanoparticles were prepared by simple precipitation and calcination processes. Their photocatalytic properties for O₂ formation from water were investigated. The composites were c.a. 2.5 times more active than WO₃ in photocatalytic O₂ formation under visible light irradiation. The formation mechanism of WO₃/TiO₂ microstructures was explained from “particle packing mode“. / Appendix II:An interestingly adsorption property of hexagonal tungsten trioxide to MB was discovered. The WO₃ were prepared from ammonium metatungstate, tetrapropyl ammonium hydroxide and potassium chloride. The product exhibited a high adsorption capacity toward methylene blue (MB), and the time required for reaching adsorption equilibrium was less than 5 seconds. The amount of MB adsorbed by WO₃ in 5 s was equivalent to that adsorbed by activated carbon for 30 min. Ionic interaction and “imprinting-adsorption“ were proposed to explain the adsorption property of as-prepared WO₃ sample. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Wang, Feng. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese. / Abstract (Chinese) --- p.i / Abstract --- p.iii / Acknowledgement --- p.vi / List of Figures --- p.viii / List of Tables --- p.xviii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Basic Principles of Photocatalytic Water Splitting --- p.1 / Chapter 1.2 --- Strategies to Develop Visible-light-driven Photocatalysts --- p.3 / Chapter 1.2.1 --- Native visible-light-driven photocatalysts --- p.3 / Chapter 1.2.2 --- Doping --- p.6 / Chapter 1.2.2.1 --- Metal or non-metal ions doping --- p.6 / Chapter 1.2.2.2 --- Co-doping --- p.10 / Chapter 1.2.2.3 --- Homogeneous doping --- p.12 / Chapter 1.2.3 --- Solid solution photocatalysts --- p.15 / Chapter 1.2.4 --- Dye sensitized photocatalysts --- p.17 / Chapter 1.3 --- Strategies to Enhance Photocatalytic Efficiency --- p.19 / Chapter 1.3.1 --- Semicondutor combination --- p.19 / Chapter 1.3.1.1 --- Inorganic sensitization --- p.20 / Chapter 1.3.1.2 --- Bidirectional charge-carrier transfer --- p.21 / Chapter 1.3.1.3 --- Indirect Z-scheme --- p.22 / Chapter 1.1.1.4 --- Direct Z-scheme --- p.23 / Chapter 1.3.2 --- Cocatalyst loading --- p.24 / Chapter 1.3.2.1 --- Noble metal cocatalysts --- p.24 / Chapter 1.3.2.2 --- Metal oxide cocatalysts --- p.25 / Chapter 1.3.2.3 --- Metal sulfide cocatalysts --- p.26 / Chapter 1.3.2.4 --- Mixed cocatalysts --- p.27 / Chapter 1.3.3 --- Hydrogen Generation Systems Containing Sacrificial Reagents --- p.32 / Chapter 1.4 --- Summary --- p.34 / Chapter 1.5 --- Aim of This Thesis and Its Significance --- p.35 / Chapter 1.6 --- References --- p.36 / Chapter Chapter Two --- Red Phosphorus: An Elemental Photocatalyst for Hydrogen Formation from Water under Visible Light Irradiation --- p.52 / Chapter 2.1 --- Introduction --- p.52 / Chapter 2.2 --- Experimental --- p.54 / Chapter 2.2.1 --- Synthesis --- p.54 / Chapter 2.2.1.1 --- Preparation of crystalline red phosphorus --- p.54 / Chapter 2.2.1.1 --- Preparation of red phosphorus films --- p.54 / Chapter 2.2.2 --- Characterization --- p.55 / Chapter 2.2.3 --- Gas evolution tests --- p.56 / Chapter 2.2.4 --- Detection of photogenerated OH radicals --- p.56 / Chapter 2.2.5 --- Computational details --- p.57 / Chapter 2.2.6 --- Photoconductivity measurements and electrical tests --- p.57 / Chapter 2.3 --- Results and Discussion --- p.59 / Chapter 2.4 --- Conclusions --- p.74 / Chapter 2.5 --- References --- p.75 / Chapter Chapter Three --- Hierarchical P/YPO4 Microsphere for Photocatalytic Hydrogen Production from Water under Visible Light Irradiation --- p.79 / Chapter 3.1 --- Introduction --- p.79 / Chapter 3.2 --- Experimental --- p.81 / Chapter 3.2.1 --- Synthesis --- p.81 / Chapter 3.2.2 --- Characterization --- p.81 / Chapter 3.2.3 --- Gas evolution tests --- p.82 / Chapter 3.3 --- Results and Discussion --- p.83 / Chapter 3.4 --- Conclusions --- p.95 / Chapter 3.5 --- References --- p.95 / Chapter Chapter Four --- Enhancement of Photocatalytic H₂ Formation from Water over Red P by Loading CoP₂ as Cocatalyst --- p.99 / Chapter 4.1 --- Introduction --- p.99 / Chapter 4.2 --- Experimental --- p.100 / Chapter 4.2.1 --- Synthesis --- p.100 / Chapter 4.2.2 --- Characterization --- p.101 / Chapter 4.2.3 --- Hydrogen formation tests --- p.101 / Chapter 4.3 --- Results and Discussion --- p.103 / Chapter 4.4 --- Conclusions --- p.109 / Chapter 4.5 --- References --- p.109 / Chapter Chapter Five --- Conclusions and Future Work --- p.112 / Chapter 5.1 --- Conclusions --- p.112 / Chapter 5.2 --- Recommendations for future work --- p.112 / Chapter Appendix I --- WO₃/TiO₂ Microstructures for Photocatalytic Water Oxidation under Visible Light Irradiation --- p.114 / Chapter AI.1 --- Introduction --- p.114 / Chapter AI.2 --- Experimental --- p.116 / Chapter AI.2.1 --- Sample preparation --- p.116 / Chapter AI.2.1.1 --- Precursor synthesis --- p.116 / Chapter AI.2.1.2 --- Synthesis of assembled WO₃/TiO₂ microstructures --- p.118 / Chapter AI.2.2 --- Characterization --- p.119 / Chapter AI.2.3 --- Oxygen formation tests --- p.120 / Chapter AI.3 --- Results and Discussion --- p.121 / Chapter AI.4 --- Conclusions --- p.137 / Chapter AI.5 --- References --- p.137 / Chapter Appendix II --- Hexagonal Tungsten Trioxide Nanorods as a Rapid Adsorbent for Methylene Blue --- p.142 / Chapter AII.1 --- Introduction --- p.142 / Chapter AII.2 --- Experimental --- p.143 / Chapter AII.2.1 --- Sample preparation --- p.143 / Chapter AII.2.2 --- Characterization --- p.144 / Chapter AII.3 --- Results and Discussion --- p.145 / Chapter AII.4 --- Conclusions --- p.159 / Chapter AII.5 --- References --- p.159 / List of Publications --- p.163

Hydrogen has a great potential to become a wide-scale, carbon free, sustainable energy carrier of the future. However its implementation and final utilization especially in mobile applications is still limited because of several technological and socio-economical barriers, mainly to do with safe, efficient storage of hydrogen with high gravimetric and volumetric storage capacities. Physisorption into nanoporous materials is an attractive option as it benefits from rapid, fully reversible adsorption/desorption and can store significant amounts of hydrogen at more moderate temperature and pressures conditions than conventional liquefaction (20.3 K) or compression (350‒700 bar). Nevertheless, the critical challenge exists to define the experimental methods that allow accurate hydrogen sorption determination and reduce discrepancies in measurements between different laboratories. This thesis presents an investigation of the experimental methodology of hydrogen sorption in porous materials. A set of nanoporous samples and characterisation techniques have been tested rigorously to explore experimental uncertainty and provide universally reproducible procedures. The validity of the standard methods and some new approaches for experimental data collection and analysis are presented. High repeatability of gas sorption isotherms measured gravimetrically and volumetrically at 77 K on reference TE 7 III carbon beads sample has been demonstrated in-house. A study has been conducted between seven laboratories to evaluate the reproducibility of nitrogen/hydrogen isotherms at 77 K according to a defined test protocol. Statistical analysis yields very good agreement between nitrogen and hydrogen sorption results. The Brunauer-Emmett-Teller surface area of 777.8 ± 6.2 m2 g-1 and Dubinin-Radushkevich micropore volume of 0.3766 ± 0.0078 cm3 g-1, have been determined. The excess hydrogen sorption capacities are found to be 1.65 ± 0.04 wt% and 2.33 ± 0.007 wt% for 1 bar and 20 bar hydrogen pressure, respectively. This study concludes that the accuracy of hydrogen sorption measurements have been pushed forward and methodology proposed here could contribute to improvements in certification of future hydrogen sorption methods.

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Chiu Lai Fan. / Thesis submitted in: December 2004. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves [74-77]). / Abstracts in English and Chinese. / ABSTRACT (ENGLISH) --- p.iii / ABSTRACT (CHINESE) --- p.v / ACKNOWLEDGMENTS --- p.vi / TABLE OF CONTENTS --- p.vii / LIST OF FIGURES --- p.ix / LIST OF TABLES --- p.xi / LIST OF SYMBOLS --- p.xiii / Chapter CHAPTER ONE --- INTRODUCTION AND BACKGROUND --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- The nature of hydrogen bonding interactions --- p.2 / Chapter 1.3 --- Evidences of hydrogen bonding interactions --- p.4 / Chapter 1.4 --- Three-centered hydrogen bond --- p.4 / Chapter 1.4.1 --- Literature review of three-centered H-bonds --- p.6 / Chapter 1.4.2 --- Review of three-centered H-bonds characterization --- p.8 / Chapter 1.5 --- Cooperative effect --- p.12 / Chapter 1.6 --- Scope of thesis --- p.13 / Chapter CHAPTER TWO --- THEORY AND METHODOLOGY --- p.15 / Chapter 2.1 --- Introduction --- p.15 / Chapter 2.2 --- Theory --- p.16 / Chapter 2.2.1 --- Density Functional Theory (DFT) --- p.16 / Chapter 2.2.2 --- Natural Bonding Orbital Theory (NBO) --- p.19 / Chapter 2.2.3 --- Spin-Spin coupling constants --- p.22 / Chapter 2.2.4 --- Wiberg Bond Index --- p.24 / Chapter 2.3 --- Methodology --- p.25 / Chapter CHAPTER THREE --- RESULTS AND DISCUSSION --- p.32 / Chapter 3.1 --- The nature of three-centered hydrogen bond interaction --- p.32 / Chapter 3.1.1 --- Geometries --- p.32 / Chapter 3.1.2 --- Natural bond orbital analysis - Donor-acceptor interactions --- p.41 / Chapter 3.1.3 --- Spin-Spin coupling across the hydrogen bonds --- p.46 / Chapter 3.1.4 --- Wiberg bond index --- p.51 / Chapter 3.1.5 --- Proton transfer -Hydrogen bond strengths on the effect of remote proton transfer --- p.53 / Chapter 3.1.6 --- Cooperactive character in hydrogen bonding clusters --- p.65 / Chapter CHAPTER FOUR --- CONCLUSING REMARKS --- p.71 / REFERENCES / APPENDIX

H₂O₂作为信号分子参与基因表达调控和植物生理与发育过程。在本论文中，我在拟南芥中发现并详细研究了H₂O₂的一个新功能--诱导黑暗中的形态建成。光呼吸是植物内源H₂O₂的主要来源，因此我构建了GOX基因过量表达转基因植株，并在黑暗中模拟了光呼吸H₂O₂产生机制，显著诱导了幼苗的黑暗形态建成。细胞周期报告株系的研究表明，在黑暗中细胞周期停滞在G2/M过渡点，而H₂O₂的处理能帮助细胞通过G2/M时期，从而在黑暗中生长出顶端分生组织。这些结果提示H₂O₂可能参与细胞周期调控。 / 然后，我研究了拟南芥中H₂O₂的产生和分布模式。H₂O₂主要集中分布于维管组织、根冠、叶毛和子叶末端。GOX1和GOX2基因恰恰在H₂O₂分布区域较高表达。在gox1-4和gox2-1突变体中，H₂O₂水平显著下降，表明GOX1和GOX2是拟南芥中主要的H₂O₂产生基因。GOX1和GOX2在发芽早期就较高表达，并伴随有H₂O₂的积累。时序基因表达数据表明在发芽过程中GOX酶的底物并非产生于光呼吸，而是脂肪代谢。因此，我提出了两阶段H₂O₂产生机制模型，即：发芽过程中脂肪代谢提供底物，而生长过程中光呼吸提供底物。 / 最后，我探索了H₂O₂诱导黑暗形态建成过程中的信号通路。利用基因芯片分析和生物信息学方法从H₂O₂和光诱导基因的启动子序列中预测了GGGCC（R-box）调控元件。该元件集中分布于-50到-250bp区域，并且在小鼠和人的基因组的相同区域中也大量分布。EMSA实验验证了该调控元件是H₂O₂可诱导的。随后从其结合的核因子中分离鉴定了2个snoRNP蛋白：fibrillarin 2和NOP56，同时还克隆了数个C/D家族snoRNA序列。这些结果表明，在拟南芥中存在着一个参与H₂O₂信号通路的snoRNP/ R-box调控机制。 / For years H₂O₂ has been known as signal molecule involved in gene expression regulation. which affect particular physiological and developmental processes. In this study, I identified and characterized a new function of H₂O₂ in Arabidopsis development. Specifically, I found that H₂O₂ can induce seedling establishment in the dark. Nitrogen and sucrose have substantial influence on the effect of H₂O₂ induced seedling establishment. Because photorespiration is a major source of H₂O₂ production, when photorespiratory H₂O₂ producing pathway was mimicked in glycolate oxidase (GOX) over-expression lines, and significantly increased seedling establishment in the dark was observed. Using reporter lines, I found that the cell cycle is largely blocked at G2/M transition checkpoint in the dark, and H₂O₂ treatment helps the cells pass through the G2/M transition and finally establish shoot apical meristem. These results provide clues on the role of H₂O₂ roles in cell cycle regulation. / Then I characterized the H₂O₂ production and distribution pattern in Arabidopsis. H₂O₂ is accumulated at high level in root vasculature, root cap, veins and distal end in cotyledons, as well as leaf trichomes. The expression sites of GOX1 and GOX2 are in accordance with the places where H₂O₂ is distributed. Both peroxisomal and cytosol H₂O₂ share the same distribution pattern, indicating that the peroxisomal H₂O₂ might be the major source of H₂O₂ in Arabidopsis. In Arabidopsis gox1-4 and gox2-1 mutants, the H₂O₂ levels are both significantly reduced in roots and shoots, the sites where GOX1 and GOX2 are highly expressed, suggesting that GOX1 and GOX2 are likely the major H₂O₂ producing enzymes in Arabidopsis plants. Both GOX1 and GOX2 genes show early expression during germination, along with the H₂O₂ accumulation. Temporal expression data suggest the GOX substrates are not derived from photorespiration, rather from glyoxylate cycle that consumes lipid metabolites to provide carbon sources during germination. A working model is proposed to explain the possible H₂O₂ production mechanism. / Finally, I explored the signaling pathway involving H₂O₂ induced seedling establishment. A GGGCC motif (R-box) was identified from the upstream sequences of H₂O₂ and light induced genes in Arabidopsis. This motif is highly enriched within the -50 to -250 bp region of the induced genes, and it is also specifically distributed in the same region in mouse and human genome. EMSA experiments revealed that several nuclear factors (NF) are bound to this motif, and the binding activities alter under the H₂O₂ treatment. Two C/D family snoRNP proteins, fibrillarin 2 and NOP56 were identified from the R-box binding NFs. Several C/D family snoRNA, including R63, U24a and Z15, were also cloned from R-box binding NFs. These data suggest a snoRNP/ R-box regulation pathway may associate with H₂O₂ signaling in Arabidopsis. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Cheng, Han. / "December 2012." / Thesis (Ph.D.)--Chinese University of Hong Kong, 2013. / Includes bibliographical references (leaves 101-114). / Abstract also in Chinese. / Thesis/Assessment Committee --- p.ii / Statement: --- p.iii / Abstract --- p.iv / 摘要 --- p.vi / Acknowledgements --- p.vii / Table of Contents --- p.viii / List of Tables --- p.x / Lists of Figures --- p.xi / List of Abbreviations --- p.xii / Chapter 1 --- p.1 / General Introduction --- p.1 / Chapter 1.1 --- H₂O₂ metabolism and homeostasis in plants --- p.2 / Chapter 1.2 --- H₂O₂ Signaling pathway --- p.4 / Chapter 1.3 --- H₂O₂ roles on Plant Growth and Development --- p.6 / Chapter 1.4 --- Project Objectives --- p.7 / Chapter 2 --- p.9 / H₂O₂ Promote Post-germinative Establishment by Accelerating G2/M Transition --- p.9 / Chapter 2.1 --- Introduction --- p.10 / Chapter 2.2 --- Materials and Methods --- p.10 / Chapter 2.2.1 --- Establishment experiment in dark conditions --- p.10 / Chapter 2.2.2 --- GUS staining --- p.10 / Chapter 3.2.4 --- Constructs and generation of transgenic plants --- p.11 / Chapter 2.2.5 --- Ammonia content measurement --- p.12 / Chapter 2.2.6 --- Glycolate oxidase activity measurement --- p.12 / Chapter 2.3 --- Results --- p.12 / Chapter 2.3.1 --- H₂O₂ facilitated Post-germinative establishment in Arabidopsis --- p.12 / Chapter 2.2.2 --- Sucrose and nitrogen source are involved in the establishment --- p.13 / Chapter 2.3.3 --- Overexpression of glycolate oxidase in Arabidopsis --- p.14 / Chapter 2.3.4 --- The H₂O₂ facilitate the establishment by promoting the G2/M transition in the shoot meristem --- p.15 / Chapter 2.4 --- Discussion --- p.16 / Chapter 3 --- p.24 / Glycolate Oxidases mediate H₂O₂ distribution in Arabidopsis --- p.24 / Chapter 3.1 --- Introduction --- p.25 / Chapter 3.2 --- Materials and Methods --- p.26 / Chapter 3.2.1 --- Plant Material and growth conditions --- p.26 / Chapter 3.2.2 --- Phenotype analyses --- p.27 / Chapter 3.2.3 --- Constructs and generation of transgenic plants --- p.27 / Chapter 3.2.4 --- Transient expression --- p.29 / Chapter 3.2.5 --- Confocal microscopy, GUS staining, and stereomicroscopy --- p.29 / Chapter 3.2.6 --- PI, HPF and H2DCFDA staining --- p.30 / Chapter 3.2.7 --- RNA extraction, RT-PCR and quantitative RT-PCR --- p.30 / Chapter 3.2.8 --- Mutants Genotyping --- p.31 / Chapter 3.2.9 --- Expression Data Analysis --- p.32 / Chapter 3.3 --- Results --- p.32 / Chapter 3.3.1 --- Characterization of glycolate oxidase family genes --- p.32 / Chapter 3.3.2 --- Tissue-specific expression of GOX family genes --- p.34 / Chapter 3.3.3 --- H₂O₂ distribution pattern is in accord with GOX1 and GOX2 expression in root and leaf --- p.36 / Chapter 3.3.4 --- The H₂O₂ distribution pattern in the cytosol is similar to that in the peroxisome --- p.37 / Chapter 3.3.5 --- Gox1 and gox2 mutants show decreased H₂O₂ distribution in root and leaf --- p.38 / Chapter 3.3.7 --- A working model for H₂O₂ patterning in Arabidopsis --- p.39 / Chapter 3.3.6 --- Gox1 and gox2 mutants show delayed vegetative-to-reproductive transition --- p.41 / Chapter 3.4 --- Discussions --- p.42 / Chapter 3.4.1 --- H₂O₂ production in plant --- p.42 / Chapter 3.4.2 --- Glycolate can be derived from lipid breakdown during germination --- p.43 / Chapter 3.4.3 --- GOX functions in developmental phases transition regulation --- p.44 / Chapter 4 --- p.63 / The Identification of a New H₂O₂ signaling pathway in Arabidopsis --- p.63 / Chapter 4.1 --- Introduction --- p.64 / Chapter 4.2 --- Materials and Methods --- p.65 / Chapter 4.2.1 --- Plant materials and culture conditions --- p.65 / Chapter 4.2.2 --- Microarray Experiment and Data Analysis --- p.65 / Chapter 4.2.3 --- Crude Nuclear Protein Extraction --- p.66 / Chapter 4.2.4 --- Gel Mobility Shift Assay --- p.67 / Chapter 4.2.5 --- Purification and Identification of R-box Binding NF proteins --- p.68 / Chapter 4.2.6 --- Antibodies --- p.69 / Chapter 4.2.7 --- Western blotting --- p.69 / Chapter 4.2.8 --- Depletion tests --- p.69 / Chapter 4.2.9 --- Shift-Western assay --- p.70 / Chapter 4.2.10 --- Cloning and Detection of snoRNAs --- p.70 / Chapter 4.2.11 --- Bioinformatic Analysis --- p.71 / Chapter 4.3 --- RESULTS --- p.72 / Chapter 4.3.1 --- Transcriptome profiling revealed that H₂O₂ responsive genes also respond to light --- p.72 / Chapter 4.3.2 --- Identification of a putative novel motif from the promoters of co-upregulated genes --- p.73 / Chapter 4.3.3 --- Verification of the GGGCC Motif by Gel Mobility Shift Assay --- p.74 / Chapter 4.3.4 --- R-box is widely found In eukaryotic gene promoters --- p.75 / Chapter 4.3.5 --- R-box is ROS responsive in higher eukaryotic species --- p.76 / Chapter 4.3.6 --- NOP56 and fibrillarin 2 proteins were identified from NF+ samples --- p.77 / Chapter 4.3.7 --- Molecular cloning and detection of box C/D family snoRNA from NF+ samples --- p.79 / Chapter 4.4 --- Discussion --- p.80 / Chapter 5 --- p.99 / Conclusions and Perspectives --- p.99 / Chapter 5.1 --- Conclusions --- p.100 / Chapter 5.2 --- Perspectives --- p.101 / References --- p.103

He, Guoyun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 62-69). / Abstracts in English and Chinese. / Title Page --- p.i / Abstract (English Version) --- p.iv / Abstract (Chinese Version) --- p.v / Acknowledgement --- p.vi / List of Tables --- p.ix / List of Figures --- p.x / List of Abbreviations and Symbols --- p.xii / Chapter Chapter One: --- Introduction --- p.1 / Chapter 1.1 --- Mismatches in DNA Duplex --- p.1 / Chapter 1.2 --- T.T Mismatches in DNA Duplex --- p.5 / Chapter 1.3 --- Purpose of the Work --- p.7 / Chapter 1.4 --- DNA Structure --- p.7 / Chapter 1.4.1 --- Structure and Nomenclature of Nucleotide --- p.7 / Chapter 1.4.2 --- Base Pairing --- p.8 / Chapter 1.4.3 --- Double Helical DNA Conformation --- p.9 / Chapter Chapter Two: --- Materials and Methods --- p.10 / Chapter 2.1 --- Sample Design --- p.10 / Chapter 2.2 --- Sample Preparation --- p.11 / Chapter 2.3 --- NMR Study --- p.11 / Chapter 2.3.1 --- Non-labile Proton Resonance Assignment --- p.12 / Chapter 2.3.2 --- Labile Proton Resonance Assignment in Normal Base Pairs --- p.13 / Chapter 2.3.3 --- Method to Determine T.T Pairing Mode --- p.14 / Chapter Chapter Three: --- Determination of T.T Pairing Mode --- p.16 / Chapter 3.1 --- NMR Resonance Assignment --- p.16 / Chapter 3.2 --- Result --- p.18 / Chapter 3.2.1 --- Preferential Pairing Mode: W --- p.18 / Chapter 3.2.2 --- Preferential Pairing Mode: W --- p.19 / Chapter 3.2.3 --- Exchanging and Pairing Modes --- p.20 / Chapter 3.3 --- Discussion --- p.23 / Chapter 3.3.1 --- Patterns of T.T Pairing Mode --- p.23 / Chapter 3.3.2 --- Reason for Preferential Pairing Mode --- p.24 / Chapter 3.3.3 --- Temperature Effect on T.T Pairing Mode --- p.26 / Chapter Chapter Four: --- Conclusions and Future Works --- p.29 / Chapter Appendix I: --- NOESY and WATERGATER-NOESY Assignment --- p.30 / Chapter Appendix II: --- Chemical Shifts of XTY --- p.46 / References --- p.62

The transition from declining conventional fossil fuel energy to renewables is one of the most significant challenges facing humanity. Hydrogen is anticipated as the key future energy vector. This is sought to bring more value and utility to renewable energy resources, and eventually providing an energy storage medium to replace fossil fuels such as for automotive applications. This thesis contains an investigation of hydrogen production through renewable low-cost and low-carbon processes. Literature reviews of conventional and renewable H₂ production methods and storage (compression, liquefaction, adsorption materials and hydrides) are presented in detail (in appendices). Particular attention has been given to energy efficiency, cost and practicality of processes. Electrolysis of water is investigated in detail. Wind turbines and solar photovoltaics are reviewed and physically investigated as key renewable electrical energy sources for renewable H₂ production via electrolysis. Conventional and novel electrical power control is investigated and tested to support low-cost wind/solar-powered electrolysis. Biological H₂ production from mixed-acid fermentation of Escherichia coli is practically investigated from the energy-physics perspective and considered as one possible route to permit renewable H₂ production in the long-term. Photocatalytic materials are also investigated as additional future routes for renewable H₂ production; in this work they are investigated using nanoscale materials processing and surface analysis techniques. This thesis has an energy-focussed, applied and practical theme, achieving a broad investigation of the topics herein. Experimental investigations were chosen based upon relevance, practicality, concurrent research, availability of resources, and for application of novel nanoscale materials processing. Power control elements for wind-powered H₂ production have for example been optimised by complete investigation of supply/load characteristics rather than adopting the more conventional power electrical/electronic approach. Ultimately the work here aims to demonstrate (at small-scale) that renewable H₂ production can be achieved at relatively low cost, e.g. by wind-powered electrolysis, inferring that pathways can be established within existing means to produce much larger quantities of renewable H₂ economically.

Magister Scientiae - MSc / Metal hydrides hydrogen storage materials have the ability to reversibly absorb and release large amounts of hydrogen at low temperature and pressure. In this study, metal hydride materials employed as negative electrodes in Ni-MH batteries are investigated. Attention is on AB5 alloys due to their intermediate thermodynamic properties. However, AB5 alloys a have tendency of forming oxide film on their surface which inhibits hydrogendissociation and penetration into interstitial sites leading to reduced capacity. To redeem this, the materials were micro-encapsulated by electroless deposition with immersion in Pd and Pt baths. PGMs were found to increase activation, electrochemical activity and H2 sorption kinetics of the MH alloys. Between the two catalysts the one which displayed better performance was chosen. The materials were characterized by X-ray difractommetry, and the alloys presented hexagonal CaCu 5–type structure of symmetry P6/mmm. No extra phases were found, all the modified electrodes displayed the same behavior as the parent material. No shift or change in peaks which corresponded to Pd or Pt were observed. Scanning Electron Microscopy showed surface morphology of the materials modified with Pd and Pt particles, the effect of using different reducing agents (i.e ., N2H4 and NaH2PO2), and alloys functionalized with γ-aminosopropyltrietheosilane solution prior to Pd deposition. From all the surface modified alloys, Pt and Pd particles were observed on the surface of the AB5 alloys. Surface modification without pre-functionalization had non-uniform coatings, but the pre- functionalized exhibited more uniform coatings. Energy dispersive X-ray Spectroscopy and Atomic Absorption Spectroscopy determined loading of the Pt and Pd on the surface of all the alloys, and the results were as follows: EDS ( Pt 13.41and Pd 31.08wt%), AAS (Pt 0.11 and Pd 0.78wt%). Checking effect of using different reducing agents N2H4 and NaH2PO2 for electroless Pd plating the results were as follows: EDS (AB5_N2H4_Pd- 7.57 and AB 5_NaH2PO2_Pd- 31.08wt%), AAS (AB5_N2H4_Pd- 11.27 and AB5_NaH2PO2_Pd- 0.78wt%). For the AB5 alloyspre-unctionalized with γ-APTES, the results were: EDS (10.24wt%) and AAS (0.34wt%). Electrochemical characterization was carried out by charge/discharge cycling controlled via potential to test the AB5 alloy. Overpotential for unmodified, Pt and Pd modified electrodes were-1.1V, -1.24V, and -1.60V, respectively. Both modified electrodes showed discharge overpotentials at lower values implying higher specific power for the battery in comparison with the unmodified electrodes. However, Pd electrode exhibited higher specific power than Pt. To check the effect of the reducing agent the results were as follows: AB5_ N2H4_Pd (0.4V) and AB5_NaH2PO2_Pd (-0.2V), sodium hypophosphite based alloy showing lower overpotential values, implying it had higher specific power than hydrazine based bath. Alloy pre-functionalized with γ-APTES, the overpotential was (0.28V), which was higher than -0.2V of the alloy without pre-functionalization, which means pre-functionalization with γ-APTES did not improve the performance of the alloy electrode. Polarization resistance of the electrodes was investigated with Electrochemical Impedance Spectroscopy. The unmodified alloy showed high resistance of 21.6884 while, both Pt and Pd modified electrodes exhibited decrease 14.7397 and 12.1061 respectively, showing increase in charge transfer for the modified electrodes. Investigating the effect of the reducing agent, the alloys exhibited the following results: (N2H497.8619 and NaH2PO212.1061 ) based bath. Alloy pre-functionalized with γ-APTES displayed the resistance of 9.3128. Cyclic Voltammetry was also used to study the electrochemical activity of the alloy electrodes. The voltammograms obtained displayed the anodic current peak at -0.64V to -0.65V for the Pt and Pd modified electrodes, respectively. Furthermore, the electrode which was not coated with Pt or Pd the current peak occurred at -0.59V. The Pd and Pt coated alloy electrodes represented lower discharge overpotentials, which are important to improve the battery performance. Similar results were also observed with alloy electrodes Pd modified using N2H4(-0.64V) and NaH2PO2(-0.65V). For the electrode modified with and without γ-APTES the over potentials were thesame (-0.65V). PGM deposition has shown to significantly improve activation and hydrogen sorption performance and increased the electro-catalytic activity of these alloy electrodes. Modified electrodes gave better performance than the unmodified electrodes. As a result, Pd was chosen as the better catalyst for the modification of AB5 alloy. Based on the results, it was concluded that Pd electroless plated using NaH2PO2 reducing agent had better performance than electroless plating using N2H4 as the reducing agent. Alloy electrode pre-functionalized with γ-APTES gave inconsistent results, and this phenomenon needs to be further investigated. In conclusion, the alloy modified with Pd employing NaH 2PO2 usased electroless plating bath exhibited consistent results, and was found to be suitable candidate for use in Ni-MH batteries / South Africa