Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第17548号 / 工博第3707号 / 新制||工||1564(附属図書館) / 30314 / 京都大学大学院工学研究科建築学専攻 / (主査)教授 髙橋 大弐, 教授 鉾井 修一, 教授 竹脇 出 / 学位規則第4条第1項該当

The work analyzes the dynamics of carbon dioxide adsorbed in crystals of anisotropic metalo-organic frameworks Zn2(BDC)2(DABCO). It utilizes nuclear magnetic resonance methods, namely, the 13 C spetroscopy, the PFG method and the measurement of longitudinal relaxation times. Experimental data are compared with calculation of molecular dynamics. The thesis provides a theoretical model for explaining the temperature dependence of the residual anisotropy of the chemical shift observed in the spectra. The method of measuring diffusion anistropy based on the change of the shape of the 13 C spectra is described. The work determines the theoretical course of dependence of the longitudinal relaxation time on temperature using Redfield's theory. Times characterizing dynamic processes running on a picosecond scale that determine the dynamics of the fluid as a whole are evaluated from the data. 2

Phosphotungstic acid H3[PMo12O40](PTA) with the Keggin structure has become well known as a solid superacid with pKa≈-13. Such a strong acidity is caused by delocalization of the negative charge of the anion on many oxygen atoms over the surface of the Keggin structure. High acidity of PTA and its good solubility in water and other polar solvents enables its use as a highly active homogeneous catalyst. However, in spite of relatively higher reaction rate, homogeneous catalysis has various drawbacks that limit its practical application. The main drawback is the difficult and expensive removal of the used catalyst from the reaction mixture and its recycling. PTA also demonstrated good catalytic activity as a heterogeneous catalyst of various organic reactions, e.g. hydrolysis, hydration and polymerization. Wide application of a pure superacid in catalysis is limited by its low surface area and solubility in polar solvents. The objective of this work is the synthesis and study of insoluble superacidic catalysts covalently embedded into the silica matrix. The catalyst PTA/SiO2 was synthesized by the sol-gel method. Tetraethoxysilane was co-condensed with PTA in acidic media in the presence of Pluronic P123 surfactant as a pore-forming agent. The obtained gel was air-dried and calcined at 500 °C producing a mesoporous material with a significant fraction of micropores in its structure. Isotherms of adsorption/desorption of nitrogen indicated cylindrical shape of the pores with necks that is typical for materials obtained with Pluronic P123 as a template. Cs-exchanged material was prepared by mixing PTA/SiO2 with a solution of CsCl. The cation exchange on cesium decreased the total pore volume due to a much higher volume of cesium ions as compared to protons. In addition, partial pore blocking by these ions restricted access to small pores thus reducing accessible surface area. Heteropolyacids are unstable in alkaline media that makes direct solid-state titration impossible. Surface acidity of the samples was determined by reversed titration. Dry samples were dispersed in a solution of pyridine in tetrahydrofuran. After equilibration, the solid phase was filtered, and the filtrate was titrated by HCl. PTA/SiO2 has a very high adsorption capacity on pyridine, which corresponds to 15 molecules of pyridine per [PMo12O40]3- anion. This number exceeded the number of available protons. The catalysts were successfully tested in the alkylation of mesitylene by alkenes. The use of superacidic materials in catalytic reactions can significantly improve the effectiveness of the processes.

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This thesis concerns three-dimensional finite element modelling of Biot's equations for elasto-acoustic modelling of wave propagation in layered media including porous elastic materials. The concept of hierarchical (p-version) finite elements are combined with various weak forms of Biot's equations. Computationally efficient methods providing accurate solutions of sound propagation in layered porous media are discussed. The research falls within the areas linear acoustics and numerical acoustics. Important applications of the developed methods may be found within vehicle interior acoustics, e.g. engineering design of damping treatment based on multiple layers of porous materials. / QC 20100618

Porous carbons are versatile materials with applications in different fields. They are used in filtration, separation and sequestration of fluids and gases, as conductive additives in many energy storage materials, as coloring agents, as pharmaceutical and food additives, and in many other vital technologies. Porous carbons produced by pyrolysis and activation of organic precursors commonly suffer from poorly controlled morphology, microstructure, chemistry, and pore structure. In addition, the poorly controlled parameters of porous carbons make it challenging to elucidate the underlying key physical parameters controlling their performance in energy storage devices, including electrochemical capacitors (ECs) and lead-acid batteries (LABs). Zeolite-templated carbons (ZTCs) are a novel class of porous carbon materials with uniform and controllable pore size, microstructure, morphology, and chemistry. In spite of their attractive properties, they have never been explored for use in LABs and their studies for ECs have been very limited. Here I report a systematic study of ZTCs applications in ECs operating at temperatures as low as - 70 C and in LABs. Greatly improved power and energy performance, compared to state of the art devices, has been demonstrated in the investigated ECs. Moreover, the application of ZTCs in LABs has resulted in a dramatic enhancement of their cycle life and power and energy densities.

Abstract This thesis conducts a comprehensive investigation of the of the physical chemistry related to the TEOS-based porous materials prepared by so-gel approach and develops the fast qualification technology for the hydrolysis and condensation reaction of sol-gel process. The porous materials were prepared by introducing a polymer polyethylene glycol (PEG) into sol-gel after different aging times and with different drying and annealing processes. The effects of pH and addition of PEG on sol-gel derived SiO2 powders for purification of ethanol are studied. The methods and results of this work provide valuable reference for the development of other functional materials such as low k dielectric materials. In the first part, the long-term behavior of the hydrolysis and condensation reaction of the tetraethoxysilane (TEOS) pre-solution at different pH values with and without addition of polyethyleneglycol (PEG) for various aging times was characterized by liquid 1H, 13C, and 29Si NMR spectroscopy.The experimental results demonstrate that alcohol was generated in the TEOS pre-solutions with and without addition of PEG at pH 3 and pH 9 after aging, implying the occurrence of hydrolysis and condensation. The rate of hydrolysis and condensation for the TEOS pre-solution at pH 3 was found to follow the trend of the pre-solution with PEG 2000 > pre-solution with PEG 200 > pre-solution without PEG. However, after adding PEG, the oxygen atom of the deprotonated silanol group (siloxy) of the hydrolyzed TEOS pre-solution at pH3 acted as a reaction center. The result indicates that the oxygen atom is more susceptible to electrophilic attack, resulting in an increased reaction rate. Consequently, the rate of hydrolysis and condensation for of the TEOS pre-solution at pH 9 follows a different order: pre-solution with PEG 200 > pre-solution without PEG > presolution with PEG 2000. The slowest reaction rate of the TEOS pre-solution when adding PEG 2000 is related to the tangled chains of PEG 2000 which sterically reduces the hydrolysis and condensation reaction. This work shows that the correlation between the pH and aging time on hydrolysis and condensation reaction of the TEOS pre-solution can be effectively monitored by liquid 1H NMR spectroscopy, supported by 13C and 29Si liquid NMR spectra. The data obtained should assist optimizing the pH, polymer type/size/concentration and the aging time in the preparation of polymer modified TEOS sols In the second part, SiO2 powders were prepared by the sol-gel in combination with oven-drying method before and after annealing.The experimental result demonstrates the rate of hydrolysis and condensation occurs at a fast rate in TEOS with and without adding PEG at pH3 than in any other pH levels. Because free space can lead to the vaporization of H2O, the ionization of ammonia decreases (i.e., reduction the amount of hydroxide ion), which arises from the rate of hydrolysis and condensation decreases when TEOS at pH9. After attaching PEG, the oxygen atom of the deprotonated silanol group (siloxy) for of the hydrolyzed TEOS pre-solution at pH 3 acted as a reaction center. The result indicates the oxygen atom is more susceptible to electrophilic attack, resulting in an increased reaction rate. Thus, a maximum in the powder yield is reached for TEOS pre-solution with and without adding PEG at pH 3. The SiO2 powder with adding PEG of higher molecular weight presents higher adsorption capacities, pertaining to a greater amount of hydrophilic hydroxyl groups of PEG with higher molecular weight. After annealing, the surface area of SiO2 powder prepared from the TEOS pre-solutions increases as compared with powder without adding PEG and enhances the adsorption of water. A potential absorbent SiO2 powders for producing purified ethanol suitable for fuel and industrial use, can be fabricated by using sol-gel route by careful selection of pH and PEG molecular weight. In addition, during the preparation and characterization of these materials, some interesting phenomena were observed, which are academically valuable. For instance, some samples show very narrow 1H MAS spectra and yet has high 1H-29Si CPMAS sensitivety. This phenomenon suggests us that CPMAS sensitivety may be improved by a new route, i.e., by properly preparing the sample so that CP efficiency is enhanced.

As the demand for high performance small electronic devices has increased, heat removal from these devices for space use is approaching critical limits. A heat pipe is a promising device to enhance the heat removal performance due to the phase change phenomena for space thermal management system. Even though a heat pipe has a big potential to remove the thermal energy from a high heat flux source, the heat removal performance of heat pipes cannot be predicted well since the first principle of evaporation has not been established. The purpose of this study is to establish a method to apply the evaporation model based on the statistical rate theory for engineering application including vapor-liquid-structure intermolecular effect. The evaporation model is applied to the heat pipe performance analysis through a pressure balance and an energy balance in the loop heat pipe.

Mercury is one of the most serious heavy metal pollution sources that threaten people’s health. For decades, people have developed many technologies and materials to capture mercury from flue gas of coal-fired plant. Currently, the most effective material for mercury absorption is powdered activated carbon, which shows increased efficiency when modified with halogen functional groups such as bromine. Metal-organic frameworks (MOFs) have potential applications in mercury capture due to their fantastic properties such as high porosity and high thermal stability. More important, their pore sizes and topology structures can be controlled through choosing different organic ligands in the syntheses. However, their mercury removal properties have not been studied so far. In this project, mercury absorption properties of selected known porous MOFs were studied, and the syntheses of new porous MOFs with functional groups for mercury absorption were investigated. Three known porous MOFs for mercury sorption properties were investigated. One of these MOFs, compound 3 shows a total efficiency greater than 90% in laboratory scale tests. Moreover, three new MOFs: [Cu(Br2BDC)2](HTEA)2 ， [Co2(BrBDC)(HCOO)2(DMF)2] and Zn2(BrBDC)(Trz)2•3H2O, (BrBDC = 2,5- dibromoterepthalicate, DMF =dimethylformamide, TEA = trimethylamine, Trz=1,2,4-triazole) were synthesized successfully. The first two compounds have two-dimensional structures, while the last compound contains three-dimensional channels with opening over 4.7 Å.

Le présent travail explore la possibilité d'adapter des matériaux poro-élastiques légers pour des applications spécifiques. En particulier, une approche de conception est présentée, combinant simulations par la méthodes des éléments finis et techniques d'optimisation, permettant ainsi d'améliorer les propriétés dynamiques et acoustiques de panneaux multicouches comprenant des matériaux poreux.Les modèles numériques sont fondés sur la théorie de Biot qui utilise des modèles équivalents fluide/solide avec des propriétés macroscopiques spatialement homogénéisées, décrivant le comportement physique des matériaux poro-élastiques. Afin de systématiquement identifier et comparer certaines propriétés spécifiques, bénéfiques ou défavorables, le modèle numérique est connecté à un optimiseur fondé sur les gradients. Les paramètres macroscopiques utilisés dans la théorie de Biot étant liés, il ne peuvent être utilisés comme variables indépendantes. Par conséquent, des lois d'échelle sont appliquées afin de connecter les propriétés macroscopiques du matériau aux propriétés géométriques microscopiques, qui elles peuvent être modifiées indépendamment.L'approche de conception est également combinée avec l'optimisation de la masse d'un panneau sandwich structure, afin d'examiner les possibilités de combiner exigences structurelles et acoustiques, qui peuvent être en conflit. En prenant le soin d'établir un équilibre entre composantes acoustiques et structurelles, des effets de synergie plutôt que destructifs peuvent être obtenus, donnant lieu à des panneaux multifonctionnels. Cela pourrait rendre l'ajout de traitements acoustiques redondant, qui par ailleurs annulerait tout ou partie du gain en masse obtenu par optimisation.Les résultats indiquent un véritable potentiel d'amélioration des propriétés dynamiques et acoustiques de panneaux multi-couches, pour un ajout minimum en termes de masse et volume. La technique de modélisation développée pourrait également être implémentée au sein d'outils numériques futures pour la conception de panneaux légers de véhicules. Cela aurait le potentiel de réduire substantiellement la masse tout en limitant, voire supprimant l'impact négatif sur les propriétés acoustiques et vibratoires, pourtant une conséquence courante de la réduction de la masse, participant ainsi à l'effort de développement de véhicules futures plus légers et efficaces. / The present work explores the possibilities of adapting poro-elastic lightweight acoustic materials to specific applications. More explicitly, a design approach is presented where finite element based numerical simulations are combined with optimization techniques to improve the dynamic and acoustic properties of lightweight multilayered panels containing poro-elastic acoustic materials.The numerical models are based on Biot theory which uses equivalent fluid/solid models with macroscopic space averaged material properties to describe the physical behaviour of poro-elastic materials. To systematically identify and compare specific beneficial or unfavourable material properties, the numerical model is connected to a gradient based optimizer. As the macroscopic material parameters used in Biot theory are interrelated, they are not suitable to be used as independent design variables. Instead scaling laws are applied to connect macroscopic material properties to the underlying microscopic geometrical properties that may be altered independently.The design approach is also combined with a structural sandwich panel mass optimization, to examine possible ways to handle the, sometimes contradicting, structural and acoustic demands. By carefully balancing structural and acoustic components, synergetic rather than contradictive effects could be achieved, resulting in multifunctional panels; hopefully making additional acoustic treatment, which may otherwise undo major parts of the weight reduction, redundant.The results indicate a significant potential to improve the dynamic and acoustic properties of multilayered panels with a minimum of added weight and volume. The developed modelling techniques could also be implemented in future computer based design tools for lightweight vehicle panels. This would possibly enable efficient mass reduction while limiting or, perhaps, totally avoiding the negative impact on sound and vibration properties that is, otherwise, a common side effect of reducing weight, thus helping to achieve lighter and more energy efficient vehicles in the future.