The synthesis of nanocrystals is unique compared to the formation of larger micron-sizesspecies as the final crystal sizes are not much larger than the primary nuclei. As a consequencethe final outcome of a nanocrystal synthesis i.e mean crystal size, concentrationand standard deviation is almost solely determined by the end of the nucleation phase. Directingthe growth of crystals beginning from aggregates of only tens of atoms into maturemonodisperse nanocrystals requires that the governing kinetics are strictly controlled at everymoment of the reaction. To effect this task various different ligands need to be employed,each performing a particular function during both nucleation and growth. (For complete abstract open document)

abstract: Membrane proteins are a vital part of cellular structure. They are directly involved in many important cellular functions, such as uptake, signaling, respiration, and photosynthesis, among others. Despite their importance, however, less than 500 unique membrane protein structures have been determined to date. This is due to several difficulties with macromolecular crystallography, primarily the difficulty of growing large, well-ordered protein crystals. Since the first proof of concept for femtosecond nanocrystallography showing that diffraction patterns can be collected on extremely small crystals, thus negating the need to grow larger crystals, there have been many exciting advancements in the field. The technique has been proven to show high spatial resolution, thus making it a viable method for structural biology. However, due to the ultrafast nature of the technique, which allows for a lack of radiation damage in imaging, even more interesting experiments are possible, and the first temporal and spatial images of an undamaged structure could be acquired. This concept was denoted as time-resolved femtosecond nanocrystallography. This dissertation presents on the first time-resolved data set of Photosystem II where structural changes can actually be seen without radiation damage. In order to accomplish this, new crystallization techniques had to be developed so that enough crystals could be made for the liquid jet to deliver a fully hydrated stream of crystals to the high-powered X-ray source. These changes are still in the preliminary stages due to the slightly lower resolution data obtained, but they are still a promising show of the power of this new technique. With further optimization of crystal growth methods and quality, injection technique, and continued development of data analysis software, it is only a matter of time before the ability to make movies of molecules in motion from X-ray diffraction snapshots in time exists. The work presented here is the first step in that process. / Dissertation/Thesis / Doctoral Dissertation Biochemistry 2014

Abstract Nanocellulose is envisioned as one of the key product innovations of future biorefineries, since it can potentially function in numerous high-end applications and replace many current petroleum-based products due to its superior properties, abundance and renewable nature. The main difficulty hindering the industrial upscaling of nanocellulose is the lack of feasible techniques for processing cellulose fibres on a nanoscale. At the same time, ongoing research efforts have concentrated on charting the suitability of nanocellulose for various novel applications. The chemical functionalization of cellulose is currently regarded as a significant step for both enhancing nanocellulose fabrication and increasing its value as a product by virtue of its adjustable surface properties. This thesis reports on the surface functionalization of cellulosic fibres by means of two new chemical pre-treatments based on periodate oxidation and sequential chlorite oxidation or reductive amination for use in the fabrication of nanocelluloses. The properties of the resulting nanocelluloses were characterized and their applicability to novel film structures was investigated. Both nanoporous thin films for composite membranes and self-standing barrier films were manufactured and studied for their suitability in water purification and packaging applications, respectively. The oxidation of cellulose to 2,3-dicarboxylic acid cellulose (DCC) significantly enhanced the nanofibril production as only 1-4 passes through the homogenizer were required for disintegration of the fibres down to nano-scale. The fabricated DCC-nanofibrils had both high optical transmittance and viscosity comparable to that of TEMPO-oxidized cellulose nanofibrils. DCC-nanofibrils with a carboxyl content of 1.75 mmol/g showed a potential for functioning as a nanoporous thin-film membrane layer in ultrafiltration tests. The second pre-treatment introduced an acid-free fabrication of amphiphilic cellulose nanocrystals (CNCs) with uniform width and length into nanocellulose production for the first time. Reaction conditions of periodate oxidation were presumed to be one of the key factors to impact the formation of either CNCs or cellulose nanofibrils. The butylamino-functionalized CNCs were used to fabricate barrier films that showed good mechanical strength and high resistance to permeation by oxygen even at elevated relative humidity. / Tiivistelmä Yksi metsäteollisuuden viimeisimmistä tuoteinnovaatiosta on nanoselluloosa, jolle on esitetty lukuisia uusia sovellusmahdollisuuksia sekä potentiaalia toimia korvaavana raaka-aineena öljypohjaisille tuotteille sen erinomaisten materiaaliominaisuuksien sekä globaalin saatavuuden ja uusiutuvuuden takia. Nanoselluloosan teollista hyödyntämistä on kuitenkin hidastanut kustannustehokkaiden valmistusmenetelmien puuttuminen. Samanaikaisesti on tehty laaja-alaista tutkimustyötä nanoselluloosan soveltuvuudesta uusiin käyttökohteisiin. Selluloosan kemiallista funktionalisointia pidetään tällä hetkellä yhtenä lupaavimpana menetelmänä tehostamaan sekä nanoselluloosan valmistusta että tuomaan lisäarvoa nanokuiduille, joiden pintaominaisuuksia voidaan muokata. Tässä työssä tutkittiin selluloosakuitujen funktionalisointia perjodaattihapetukseen sekä kloriittihapetukseen tai pelkistävään aminointiin perustuen ja nanoselluloosan valmistusta esikäsitellystä selluloosasta. Työssä tutkittiin erityisesti valmistettujen nanoselluloosien ominaisuuksia ja selvitettiin niiden soveltuvuutta uudentyyppisiin filmirakenteisiin. Filmirakenteita muokkaamalla tehtiin nanohuokoisia komposiittimembraaneita vedenpuhdistukseen sekä barrier-filmejä pakkausmateriaaleihin. Selluloosan hapetus 2,3-dikarboksyylihapposelluloosaksi tehosti nanoselluloosan valmistusta huomattavasti ja kuidut saatiin hajotettua 1-4 läpäisyllä homogenisaattorissa. Valmistetut DCC-nanofibrillit olivat optisesti läpinäkyviä sekä niiden viskositeetti oli yhtä korkea kuin aiemmin raportoiduilla TEMPO-hapetettuilla nanofibrilleillä. Ultrasuodatuskokeissa DCC-nanofibrilleistä pystyttiin muodostamaan nanohuokoinen kerros membraaninpinnalle, jota on mahdollista käyttää vedenpuhdistuksessa. Pelkistävällä aminointiesikäsittelyllä selluloosakuiduista onnistuttiin ensimmäistä kertaa valmistamaan kooltaan yhdenmukaisia amfifiilisiä selluloosananokiteitä ilman yleisesti käytettyä happohydrolyysiä. Siten työssä nanoselluloosien valmistukseen käytetyn perjodaattihapetuksen havaittiin soveltuvan sekä selluloosananokiteiden että selluloosananofibrillien valmistukseen. Butyyliamino-funktionalisoiduista selluloosananokiteistä valmistetut barrier-filmit olivat mekaanisesti vahvoja ja ne ehkäisivät hapenläpäisyä jopa korkeassa ilmankosteudessa.

Lors des dix dernières années, les films multicouches ont suscité l’intérêt de la communauté scientifique pour leurs propriétés innovantes. Principalement issus de l’association de polyélectrolytes et/ou de nanoparticules de différentes morphologies, ils ont ouvert la voie à la fabrication d’une nouvelle catégorie de matériaux nanoporeux, possédant des propriétés optiques attractives telles que la coloration structurale et l’antireflet. Les films multicouches à base de deux nanoparticules de charges opposées sont plus rares et permettent de jumeler les propriétés des deux nanoparticules utilisées et d’en faire émerger de nouvelles. Dans cette étude, nous nous sommes intéressés à deux nanoparticules anisotropes, de facteurs d’aspects contrôlés et respectivement bio/geosourcées : les nanocristaux de cellulose (NCC) et des nanotubes d’imogolite. Le but de cette étude est d’étudier la possibilité de créer un film multicouche bio-géo inspiré à base de ces deux nanoparticules par immersion et d’en étudier les propriétés optiques. Dans un premier temps, nous avons comparé les films multicouches NCC/Ge-imogolites à ceux plus communément décrits dans la littérature, à savoir, des films à base de NCC ou d’imogolite associés à un polyélectrolyte de charge opposée. Les différents paramètres de trempage comme le temps d’immersion et la force ionique de la suspension ont été variés afin d’obtenir une densité de film optimale. Pour finir la porosité des films et leur comportement dans l’eau ont été étudiés par QCM-D, ainsi que leurs propriétés optiques par mesure de transmittance. / In the past decade, multilayer thin films drew the scientific community attention for their unique properties. Indeed, principally made of an association of polyelectrolytes and/or nanoparticles, of various morphologies and chemistries, they allow the design of a range of porous nanomaterials with unique optical properties, such as structural colors or anti-reflectivity. Less commonly described, thin films made of two nanoparticles of opposite charges are gaining interest since they combine the properties of the two nanoparticles used, and generate new ones through their association. In this study, multilayer coatings were formed through the association of two anisotropic oppositely charged nanorods of well-controlled aspect ratio, i.e. bio-based anionic cellulose nanocrystals (CNC) and geo-based cationic Imogolites. This study deals with the feasibility to create a bio-geo-inspired multilayer thin film based on these two nanoparticles by dipping and characterize their optical properties. Firstly, elaboration of multilayered thin films from CNC and Ge-Imogolites nanorods, were studied in comparison with reference films incorporating CNC or Imogolites with polyelectrolytes bearing opposite charges of the nanorods. Multilayered thin films were assembled by the dipping procedure and various parameters (adsorption time, ionic strength, etc.) were varied to investigate the optimal density for the film. To finish, film porosities were investigated using QCM-D, and optical properties were investigated by transmittance measurements.

Influence of transformer lamination from amorphous steel on permeability disturbance by transformer This diploma work is about difference between current materials and amorphous plates which are used as pivots of transformers. Samples are tested by frequence 50-2500 Hz. By using more suitable materials we avoid the unallowable electromagnetic interruption better and we get more positive continuance of the retroactivity on the net.

In the main part of this thesis I study the relaxation mechanisms of charge carriers in silicon nanocrystals in SiO2 matrix. One of the potential applications of these structures lies in photovoltaics, specifically in construction of all-silicon tandem solar cells. I studied the dynamics of carriers in these structures by methods of ultrafast spectroscopy which helped to unravel the microscopic behaviour of carriers, their transport, localization etc. Furthermore I investigated the doping of such structures as the technology of doping is crucial for manufacture of pn- junctions which are the core component of solar cells. At the end I delve into the dissipative Jaynes-Cummings model by mathematical modeling and theoretical calculations which describes among others microlasers and as such comes under a field of cavity quantum electrodynamics.

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The study of crystal nucleation represents a considerable challenge to both experiment and theory. Crystallisation from solutions is initiated by the association of only a few ions. The resulting aggregates are the embryonic precursors to crystals and exhibit diameters of less than a nanometre. While experimental studies offer a wide variety of insights at the macroscopic scale, the atomistic level of detail often remains elusive. On the other hand, computer simulation approaches may easily achieve microscopic resolution and hence appear particularly suited for analysis of the mechanisms of ion aggregation. On the basis of atomistic models, new insights are obtained into the early steps of ion association and the self-organisation of disordered aggregates into crystalline structures. / Das Studium der Nukleation von Kristallen stellt eine immense Herausforderung sowohl an die Experimentatoren als auch an die Theoretiker dar. Die Bildung eines Kristalls aus einer Lösung beginnt mit dem Zusammenschluss einzelner Ionen zu kleinen Aggregaten. Diese embryonalen Vorstufen von Kristallen umfassen nur einige Teilchen und weisen Durchmesser von weniger als einem Nanometer auf. Experimentelle Untersuchungen sind oftmals auf die makro- und mesoskopische Größenskala beschränkt und können vergleichsweise wenige Informationen über die atomaren Aggregationsprozesse liefern. Molekulare Simulationen verlaufen im Gegensatz dazu unmittelbar auf der atomaren Detailstufe und stellen so eine hervorragende Ergänzung zum Experiment dar. Im Computer werden dabei Modellszenarien entwickelt, die Aufschlüsse über die elementaren Schritte der Aggregation von Ionen geben können und aufzeigen, wie sich zunächst ungeordnete Agglomerate allmählich zu periodisch geordneten Strukturen organisieren.

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京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19038号 / 農博第2116号 / 新制||農||1031(附属図書館) / 学位論文||H27||N4920(農学部図書室) / 31989 / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 木村 恒久, 教授 西尾 嘉之, 教授 髙野 俊幸 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM