京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18539号 / 理博第4015号 / 新制||理||1579(附属図書館) / 31439 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 阪部 周二, 教授 田中 貴浩, 准教授 橋田 昌樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18998号 / 工博第4040号 / 新制||工||1622(附属図書館) / 31949 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 作花 哲夫, 教授 安部 武志, 教授 田中 勝久 / 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19732号 / 工博第4187号 / 新制||工||1646(附属図書館) / 32768 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 作花 哲夫, 教授 安部 武志, 教授 阿部 竜 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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Analytické metody LIBS a LA-IPC-MS založené na Laserové Ablaci (LA) nabízejí možnost rychlé chemické analýzy přímo z povrchu vzorku. Nedávno bylo ukázáno, že interakce světla s nanočásticemi může být využita pro zlepšení analytických schopností těchto metod. Při interakci nanočástic s laserovým paprskem dochází k zesílení elektromagnetického pole v jejich blízkém okolí. Pokud jsou nanočástice přítomny na povrchu vzorku analyzovaném některou z metod založenou na LA, zesílené pole vytvořené interakcí laseru s částicemi může pozměnit průběh LA, a tak ovlivnit vlastnosti laserem indukovaného plazmatu. Bylo zjištěno, že použití nanočástic může snížit práh ablace, zesílit signál a změnit vlastnosti aerosolu. Nanočásticemi zesílená LIBS (NELIBS) našla své využití tam, kde použití konvenční LIBS je problematické, a to například při analýze vzorků, kdy je jejich poškození nežádoucí nebo u analýzy roztoků mikrolitrových objemů s limity detekce nižšími než ppm. Tato dizertační práce předkládá podrobný popis jevů doprovázejících nanočásticemi zesílenou LA, založený na rozsáhlé experimentální práci a fyzikální teorii. Na základě pochopení základních principů byly vyvinuty dvě nové aplikace. Nejprve, byla NELIBS použita pro detekci kovových iontů v řetězcích amyloidů, pokročilého bio-materiálu určeného pro čištění vody. Dále byla NELIBS využita jako nová metoda pro monitorování proteinové korony vytvořené kolem nanočástic, čímž tato aplikace rozšířila klasické použití NELIBS za hranice prvkové analýzy.

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Laser filamentation is a non-diffracting propagation regime consisting of an intense core that is surrounded by an energy reservoir. For laser ablation based spectroscopy techniques such as Laser Induced Breakdown Spectroscopy (LIBS), laser filamentation enables the remote delivery of high power density laser radiation at long distances. This work shows a quasiconstant filament-induced mass ablation along a 35 m propagation distance. The mass ablated is sufficient for the application of laser filamentation as a sampling tool for plasma based spectroscopy techniques. Within the scope of this study, single-shot ablation was compared with multi-shot ablation. The dependence of ablated mass on the number of pulses was observed to have a quasi-linear dependence on the number of pulses, advantageous for applications such as spectroscopy. Sample metrology showed that both physical and optical material properties have significant effects on the filament-induced ablation behavior. A relatively slow filament-induced plasma expansion was observed, as compared with a focused beam. This suggests that less energy was transferred to the plasma during filamentinduced ablation. The effects of the filament core and the energy reservoir on the filamentinduced ablation and plasma formation were investigated. Goniometric measurements of the filament-induced plasma, along with radiometric calculations, provided the number of emitted photons from a specific atomic transition and sample material. This work advances the understanding of the effects of single filaments on the ablation of solid materials and the understanding of filament-induced plasma dynamics. It has lays the foundation for further quantitative studies of multiple filamentation. The implications of this iv work extend beyond spectroscopy and include any application of filamentation that involves the interaction with a solid material

This dissertation demonstrated that the manipulation of substances at the molecular or nanometer level can lead to the discovery and development of new materials with interesting properties and important applications. Chapter 1 describes the development of a nanoscale molecular thin film material for corrosion protection. By using a self-assembled monolayer film with a thickness of only about 1 nanometer as a linkage, a covalent bonding was achieved between a polyurethane top coating and an aluminum alloy substrate. This covalent bonding between polymer top coating and the aluminum alloy substrate significantly improved the corrosion resistance of the substrate. Chapter 2 and Chapter 3 describe the development of a gold nanoparticle-polymer composite material in different forms with a number of applications. Gold nanoparticles are among one of the most extensively studied nanomaterials. When the size of gold is shrunk to the nanometer scale, many interesting and new physical properties start to appear from gold nanoparticles. The optical properties of gold nanoparticles, particularly the surface plasmon resonance absorption, have been investigated in this dissertation for the development of multifunctional nanocomposite materials. Chapter 2 presents the preparation of a gold nanoparticle/poly(methyl methacrylate) (PMMA) nanocomposite film and the application of such films for microstructure fabrication using a direct laser writing technique. Gold nanoparticles are excellent photon-thermal energy converters due to their large absorption cross section at the surface plasmon resonance region. Upon laser irradiation of the nanocomposite film, the thermal energy converted from the absorbed photon energy by gold nanopaticles induced a complete decomposition of PMMA, leading to the formation of various microstructures on the nanocomposite films. Chapter 3 reports the further development of a nanoparticle/polymer composite nanofiber material fabricated through an electrospinning process. The matrix of the nanofiber is made of two polyelectrolytes, poly(acrylic acid) (PAA) and poly(allylamine hydrochloride) (PAH). Three methods were developed to incorporate gold nanoparticles into the polymer matrix. The composite nanofiber materials developed in this study demonstrate multifunctional properties, including good electrical conductivity, photothermal response, and surface-enhanced IR absorption. This material may be used for many important applications including catalysis, chemical and biological sensors, and scaffold materials for tissue engineering. In Chapter 4, another most important nanomaterial, carbon naotubes (CNTs), were introduced as fillers to prepare polymer nanocomposites. A dispersion method for multi-walled carbon nanotubes (MWCNTs) using a conjugated conducting polymer, poly(3-hexylthiophene) (P3HT) as the third component and trifluoroacetic acid (TFA) as a co-solvent was developed. Due to the excellent dispersion of carbon nanotubes in PMMA and enhanced conductivity of the nanocomposites by the conjugated conducting polymers, the prepared composite materials has an extremely low percolation threshold of less than 0.006 wt% of MWCNT content. The potential use of MWCNT/conducting polymer composites for energy storage applications such as suppercapacitors was further investigated by Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS) and charging-discharging cycles. Compared to pure carbon nanotubes, the nanocomposite materials have significantly improved properties and are promising for supercapacitor applications.

Tooth enamel is among the most durable substances in the human body and as such has high recoverability in forensic anthropology cases. Its crystalline hydroxyapatite matrix has a slightly variable chemical composition which incorporates biologically available trace elements. The trace elements are derived from an individual's diet and the water he or she consumes during the period of enamel formation. As a result, trace element profiles of enamel can reflect the geology, pollution, and certain cultural dietary factors of the area in which the individual resided during this period. This research examines a sample of teeth with known demographic information from the Antioquia Modern Skeletal Reference Collection in Medellin, Colombia. A sample set of 75 teeth from 61 individuals born in areas throughout northwestern Colombia were analyzed using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), a minimally destructive, semi-quantitative technique. Analysis was performed at the Center for Archaeology, Materials, and Applied Spectroscopy (CAMAS) at Idaho State University. 33 elements were analyzed in the sample. Nonparametric methods were used to assess the relationship between elemental profiles and region of origin. Sr, Mo, Ag, Ba, Eu, and Tm concentration profiles were found to vary among regional groups. Al, Ni, Cr, Mn, Co, Sr, Cd, Sb, Sm, Eu, and U were found to predict region of origin. Differences in municipality were classified with 72% accuracy, variation across the department of Antioquia was classified with 67% accuracy, and the age of the geologic substrate was classified with 67% accuracy. The results suggest that trace element analysis of permanent tooth enamel may be of some use in estimating an individual's region of origin in forensic anthropological contexts. Further research with both larger sample sizes and more geographic variation is necessary.