京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22662号 / 工博第4746号 / 新制||工||1742(附属図書館) / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 杉野目 道紀, 教授 村上 正浩, 教授 中尾 佳亮 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

This diploma thesis deals with the problems of revitalization of historical objects. The theoretical part describes the technologies for static reinforcing and rehabilitation of vertical and horizontal bearing structures for a purpose of increasing the general stiffness of the object. As the practical part a static design project is made for reinforcing of the bearing walls and also for the general reconstruction of the slab. The slab is designed as the composite timber-concrete structure. The design project of the slab is economically compared with other variants. The designs are made for an existing object of the old restaurant in the village Velichovky.

This diploma thesis deals with the machining process of pinion gearing in the company Šmeral Brno a.s. The first part aims at the basic description of the thesis subject – the pinion. General gear machining technologies and its inspection is processed in the second part. The third part is focused on the description of the current machining process, its weaknesses and strengths. The main part consists of the machinery and tool choice, of the proposal of the gearing technological process for five-axis machining center and of the production time calculations. In conclusion, technological and economic impacts of the proposal are evaluated.

The purpose of this work is to look into the fundamental issues regarding spring design and develop a new, easy to use software program that would allow for optimal, flexible spring designs. Most commercial programs that address this function are basic and do not allow the designer much control over the variables hindering design. This is so because most programs start from the premise that the spring is a general purpose part of the system or that other design parameters can be altered to accommodate the chosen spring. In cases where this is not so, such as in hydraulic cartridge valves, where the geometric constraints are severe, spring design may be a cumbersome process. This is particularly true when fatigue life is taken into account. The solution chosen here is to tailor the software application to these particular design constraints, incorporating some ideas about spring optimization. In addition to this, a concerted effort was made to make the subject more accessible to the engineers using the program by automating the more technical aspects of the process allowing the designers to make intelligent decisions based on how the variables would affect design. To this end currently existing software was evaluated to determine where it was lacking and a new program was written and painstakingly tested. Finally, it was used to correct flaws identified in existing springs.

Various ways of preparing enantiomerically pure 2-amino[6]helicene derivatives were explored. Ni(0) mediated cyclotrimerization of enantiopure triynes provided (M)- and (P)-7,8-bis(p-tolyl)hexahelicene-2-amine in >99% ee as well as its benzoderivative in >99% ee. The stereocontrol was found to be inefficient for a 2- aminobenzo[6]helicene congener with an embedded five-membered ring. Helically chiral imidazolium salts bearing one or two helicene moieties have been synthesized and applied in enantioselective [2+2+2] cyclotrimerization catalyzed by an in situ formed Ni(0)-NHC complex. The synthesis of the first helically chiral Pd- and Ru- NHC complexes and their application in enantioselective catalysis was demonstrated. The latter shows promising results in enantioselective olefin metathesis reactions. A mechanistic proposal for asymmetric ring closing metathesis is provided.

Physics and potential applications of femtosecond laser pulses interacting with matter have captured interest in various fields, such as nonlinear optics, laser micromachining, integrated optics, and solar cell technologies. On the one hand, such ultrashort intense pulses make them practical elegant tools to be utilized for direct structuring of materials with high accuracy and numerous potential applications. On the other hand, studying the fundamental aspects and nonlinear nature of such interactions opens new remarkable venues for various unique investigations. In recent years, the emerging topic of structured light (also known as twisted or optical vortex light), i.e., a beam of light with a twisted wave-front that can carry orbital angular momentum (OAM), has attracted the attention of many researchers working in the field of light-matter interaction. Such beams offer various applications from classical and quantum communication to imaging, micro/nano-manipulation, and modification of fundamental processes involved in light-matter interactions, e.g., absorption and emission. Nevertheless, the fabrication of complex structures, controlled modification, and achieving a high spatial resolution in material processing still remain in the spotlight. Moreover, the fundamental role of orbital angular momentum in the nonlinear absorption of materials, particularly in solids, has yet remained a subject of debate. Addressing these points was the main motive behind this dissertation. To accomplish this objective and investigate new aspects of structured light-matter interaction, I conducted various experiments, the results of which are presented in this work. The general idea was to study the interaction of femtosecond laser radiation, having a structured phase and polarization, with the matter in two aspects: (i) surface morphology modification and (ii) nonlinear absorption of solids. In this regard, I studied surface processing of crystalline silicon and CVD diamond with femtosecond laser vortex pulses generated by a birefringent phase-plate, known as q-plate, in single and multiple pulse irradiation regimes, respectively. The characterization of the modified region was performed using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). I demonstrated that upon irradiation of a single vortex pulse on silicon, a nano-cone structure is formed within the ablated crater, whose height was independent of the helicity of the twisted light. However, for a linearly polarized vortex pulse, the height of the nano-cone decreases at higher pulse energies. The dynamics of nano-cone formation and the role of polarization were also investigated by simulating the mass transport function in this process. Moreover, using superimposed vortex beams, we fabricated complex patterns containing several nano-cones, by single-shot irradiation on the silicon surface. My experimental results offer an ability to actively control and manipulate material, in terms of the nanocones position, in two dimensions with an ultra-high resolution. I further proceeded with our experiments in the multiple pulse regime on a diamond target. By irradiation of a high number of superimposed vortex pulses, I was able to imprint complex polarization states of structured light on the target surface in the form of periodic nano-ripples. This procedure enabled us to not only generate spatially varying nano-gratings but also directly visualize and study very complex states of polarization. Besides these surface structuring, I carried out experimental studies to investigate the response of bulk material to an incident circularly polarized vortex beam that carries orbital angular momentum. The experimental results reveal, for the first time, that such an interaction can produce a differential absorption that gives rise to helical dichroism. We demonstrate that this response is sensitive to the handedness and degree of the twist in the incident vortex beam. Such a dichroism effect may be attributed to the excitation of dipole-forbidden atomic transitions, e.g., electric quadrupole transitions. However, this explanation is not absolute and remains open to further research and investigations.

Les hélicènes sont des composés polyaromatiques générant un squelette hélicoïdal. Si ces structures ont trouvé de nombreuses applications en chimie des matériaux, les résultats en catalyse asymétrique sont moins nombreux, surtout en ce qui concerne les hélices phosphorées. Au cours de cette thèse, nous avons développé des nouvelles voies d'accès à des phosphines possédant une chiralité hélicoïdale, et où le phosphore est inclus dans l'hélice elle-même, à son extrémité. Les structures hélicoïdales souhaitées ont été synthétisées par deux méthodologies différentes, faisant intervenir soit une étape de photocyclisation diastéréosélective ou soit une réaction de cyclotrimérisation [2+2+2] d'alcynes. Les deux voies synthétiques développées font intervenir le même motif phosphindole. Les phophahélicènes synthétisés ont été évalués en tant que ligand en catalyse énantiosélective à l'or. Une bonne activité catalytique et des excès énantiomériques atteignant 96% ont été mesurés dans des réactions de cycloisomérisation d'énynes ou de cycloadditions [2+2] et [4+2].Les phosphahélicènes ont aussi été testés dans des réactions d'organocatalyse par les phosphines. Dans ce cas, des excès énantiomériques allant jusqu'à 97% ont été obtenus dans une réaction de cyclisation [3+2] entre une oléfine activée et un allénoate. / Helicenes are ortho-fused polyaromatic compounds in which benzene rings are angularly annulated to give helically-shaped molecules.Molecular scaffolds with helical chirality have been rarely used for building phosphorus ligands and catalysts. In this context, with the purpose of accessing unprecedented chiral auxiliaries for organo- and organometallic catalysis, we have synthesized new series of phosphahelicenes. These compounds have been prepared via two differents procedures: a diastereoselective photochemical cyclization and a [2+2+2] cyclotrimerisation of alkynes, starting from phosphindole as a key building block. These phosphahelicenes have been evaluated as chiral ligand in gold promoted cyclisation reactions. These helical gold complexes proved to be highly efficient both in terms of catalytic activity and enantioselectivity in enyne cycloisomerizations, [2+2] and [4+2] cycloaddition reactions. Phosphahelicenes have also been used in phosphine organocatalysis. Good yields and enantiomercic excesses up to 97% have been obtained in [3+2] cyclizations between olefins and allenoates.

A thrust augmented nozzle for hybrid rocket systems is investigated. The design lever-ages 3-D additive manufacturing to embed a helical fuel port into the thrust chamber of a hybrid rocket burning gaseous oxygen and ABS plastic as propellants. The helical port significantly increases how quickly the fuel burns, resulting in a fuel-rich exhaust exiting the nozzle. When a secondary gaseous oxygen flow is injected into the nozzle downstream of the throat, all of the remaining unburned fuel in the plume spontaneously ignites. This secondary reaction produces additional high pressure gases that are captured by the nozzle and significantly increases the motor’s performance. Secondary injection and combustion allows a high expansion ratio (area of the nozzle exit divided by area of the throat) to be effective at low altitudes where there would normally be significantly flow separation and possibly an embedded shock wave due. The result is a 15 percent increase in produced thrust level with no loss in engine efficiency due to secondary injection. Core flow efficiency was increased significantly. Control tests performed using cylindrical fuel ports with secondary injection, and helical fuel ports without secondary injection did not exhibit this performance increase. Clearly, both the fuel-rich plume and secondary injection are essential features allowing the hybrid thrust augmentation to occur. Techniques for better design optimization are discussed.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19705号 / 工博第4160号 / 新制||工||1642(附属図書館) / 32741 / 京都大学大学院工学研究科原子核工学専攻 / (主査)教授 福山 淳, 教授 功刀 資彰, 教授 村上 定義 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20408号 / 工博第4345号 / 新制||工||1673(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 赤木 和夫, 教授 古賀 毅, 教授 辻井 敬亘 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM