Дисертації з теми "Electron-component"

The thesis is primarily concerned with the design, construction and preliminary commissioning of a novel polarimeter for full three-dimensional analysis of electron spin polarisation. The polarimeter is described in detail, together with the theoretical basis for its operation. Studies of an amorphous ferromagnetic alloy, Co66Fe4Ni1B14Si15, and its application as a secondary standard are presented. Finally, a design study of a GaAs polarised electron source, capable of providing both longitudinal and transverse polarisations, is detailed.

Die Toluol-Dioxygenase von Pseudomonas putida F1 ist eine Rieske-Dioxygenase und besteht aus Reduktase-, Ferredoxin- und Oxygenase-Komponente. Sie katalysiert den ersten Schritt im aeroben Abbau von Toluol. Ein effizienter Elektronentransfer zur terminalen Oxygenase-Komponente - an der die Sauerstoffaktivierung und Umwandlung von Toluol zum cis-Toluol-Dihydrodiol stattfindet - setzt eine reibungslose Interaktion aller Komponenten voraus. Die Ergebnisse der Stopped-flow-Messungen in der reduktiven Halbreaktion zeigen, dass NADH die Reduktase mittels Hydridtransfer reduziert, wodurch ein stabiler Ladungstransfer-Komplex zwischen NAD+ und FADH- entsteht. In der oxidativen Halbreaktion wird dieser dann durch einen Elektronenakzeptor über das blaue Semichinon zum Chinon oxidiert. Dabei zeigt sich, dass der Ladungstransfer-Komplex die Reaktion der Reduktase mit Sauerstoff unterdrückt. Eine Erklärung hierfür liefert die Kristallstruktur des Ladungstransfer-Komplexes. Die Reaktion mit Sauerstoff wird dadurch unterdrückt, dass das NAD+ koplanar mit dem Isoalloxazinring ist und den reaktiven N5-C4a Teil des FADs schützt und zudem den Isoalloxazinring in eine planare, weniger sauerstoffempfindliche Konformation zwängt. Durch die Bildung des Reduktase-Ferredoxin-Komplexes wird ein effizienter Elektronentransfer folgendermaßen ermöglicht: a) das Ferredoxin bindet an die Reduktase aufgrund elektrostatischer Anziehung entgegengesetzter Oberflächenladungen beider Proteine, b) die hydrophobe Region, die die beiden Redoxzentren umgibt, fungiert als Ein- und Ausgang für Elektronen und c) die geringe Entfernung von 11.7 Å zwischen beiden Kofaktoren erlaubt einen schnellen Elektronentransfer. Die Ergebnisse dieser Arbeit zeigen, dass der Elektronentransfer zwischen Reduktase und Ferredoxin durch die Bildung eines stabilen Ladungstransfer- und Reduktase- Ferredoxin-Komplexes beeinflusst wird und dadurch das Problem einer ungewollten Reaktion mit Sauerstoff umgangen wird.
The toluene dioxygenase from Pseudomonas putida F1 is a three-component Rieske non-heme iron dioxygenase comprising of a reductase, ferredoxin and an oxygenase component. It catalyzes the initial step in the aerobic degradation of toluene to cis-toluene dihydrodiol. A smooth interaction between all three components needs to be ensured to efficiently transfer the electrons derived from NADH oxidation to the terminal oxygenase component where molecular oxygen is activated and used for the hydroxylation of toluene. The results of the kinetic studies of the reductive half reaction of reductase reveal that NADH reduces the reductase, resulting in the formation of a stable charge transfer complex between NAD+ and FADH-. Oxidation of the charge transfer complex by an electron acceptor proceeds via the neutral semiquinone to the quinone state of FAD. It is shown that the charge transfer complex suppresses the reaction of the reductase with dioxygen. An explanation for this change in reactivity can be deduced from the structure of the charge transfer complex. Its slower reaction with dioxygen results from NAD+ lying coplanar with the FAD shielding its reactive N5-C4a locus and the forced planarity of the isoalloxazine ring. The formation of the reductase-ferredoxin complex allows efficient electron transfer from reductase to ferredoxin because a) the oppositely charged interacting surfaces of both proteins facilitate the pre-orientation of the ferredoxin on the reductase, b) a hydrophobic region surrounding the two redox centers in the complex acts as an exit/entrance port for electrons and c) the short edge-to-edge distance between both cofactors of 11.7 Å guarantees a fast electron transfer. The results demonstrate that the electron transfer between reductase and ferredoxin is governed by the formation of a stable charge transfer and of a reductase-ferredoxin complex with which the problem of an unwanted side reaction with dioxygen is obviated.

Electron transfer phenomena in proteins represent one of the most common types of biochemical reactions. They play a central role in energy conversion pathways in living cells, and are crucial components in respiration and photosynthesis. These complex biochemical reaction cascades consist of a series of proteins and protein complexes that couple a charge transfer to different forms of chemical energy. The efficiency and sophisticated optimisation of signal transfer in these natural redox chains has inspired engineering of artificial architectures mimicking essential properties of their natural analogues. Implementation of direct electron transfer (DET) in protein assemblies was a breakthrough in bioelectronics, providing a simple and efficient way for coupling biological recognition events to a signal transducer. DET avoids the use of redox mediators, reducing potential interferences and side reactions, as well as being more compatible with in vivo conditions. However, only a few haem proteins, including the redox protein cytochrome c (cyt.c), and blue copper enzymes show efficient DET on different kinds of electrodes. Previous investigations with cyt.c have mainly focused on heterogeneous electron transfer of monolayers of this protein on gold. An important advance was the fabrication of cyt.c multilayers by electrostatic layer-by-layer self-assembly. The ease of fabrication, the stability, and the controllable permeability of polyelectrolyte multilayers have made them particularly attractive for electroanalytical applications. With cyt.c and sulfonated polyaniline it was for the first time possible that fully electro-active multilayers of the redox protein could be prepared. This approach was extended to design an analytical signal chain based on multilayers of cyt.c and xanthine oxidase (XOD). The system does not need an external mediator but relies on an in situ generation of a mediating radical and thus allows a signal transfer from hypoxanthine via the substrate converting enzyme and cyt.c to the electrode. Another kind of a signal chain is based on assembling proteins in complexes on electrodes in such a way that a direct protein-protein electron transfer becomes feasible. This design does not need a redox mediator in analogy to natural protein communication. For this purpose, cyt.c and the enzyme bilirubin oxidase (BOD, EC 1.3.3.5) are co-immobilized in a self-assembled polyelectrolyte multilayer on gold electrodes. Although these two proteins are not natural reaction partners, the protein architecture facilitates an electron transfer from the electrode via multiple protein layers to molecular oxygen resulting in a significant catalytic reduction current. Finally, we describe a novel strategy for multi-protein layer-by-layer self-assembly combining cyt.c with an enzyme sulfite oxidase (SOx) without use of any additional polymer. Electrostatic interactions between these two proteins with rather separated pI values during the assembly process from a low ionic strength buffer were found sufficient for the layer-by-layer deposition of the both biomolecules. It is anticipated that the concepts described in this work will stimulate further progress in multilayer design of even more complex biomimetic signal cascades taking advantage of direct communication between proteins.
Elektronentransferphänomene in Proteinen stellen den häufigsten Typ biochemischer Reaktionen dar. Sie spielen eine zentrale Rolle bei der Energieumwandlung in der Zelle und sind entscheidende Komponenten in der Atmung und Photosynthese. Diese komplexen Kaskaden biochemischer Reaktionen setzen sich aus einer Reihe von Proteinen und Proteinkomplexen zusammen, die den Energietransfer an verschiedene Formen chemischer Energie koppeln. Die große Effektivität und Selektivität des Signaltransfers in diesen natürlichen Redoxketten war Vorbild für die Entwicklung künstlicher Architekturen, die die wesentlichen Eigenschaften ihrer natürlichen Analoga nachahmen. Die Implementierung des direkten Elektronentransfers (DET) von Proteinen mit Elektroden war ein Durchbruch im Bereich der Bioelektronik. Sie lieferte einen einfachen und effizienten Weg für das Koppeln biologischer Erkennungsereignisse an einen Signalumwandler. Durch den DET können Redoxmediatoren vermieden und damit potentielle Grenzflächen und Nebenreaktionen reduziert werden. Ebenso wird damit die Kompatibilität für in vivo Bedingungen erhöht. Jedoch zeigen nur einige Hämproteine wie das Redoxprotein Cytochrom c (Cyt c) und blaue Kupferproteine einen effizienten DET auf verschiedenen Elektrodentypen. Bisherige Untersuchungen mit Cyt c konzentrierten sich hauptsächlich auf den heterogenen Elektronentransfer von Monoschichten dieses Proteins auf Gold. Ein wichtiger Fortschritt war die Herstellung von Cyt c Multischichten durch die elektrostatische Layer-by-Layer-Technik. Die einfache Herstellung, die Stabilität sowie die kontrollierbaren Permeationseigenschaften von Polyelektrolyt-Multischichten machte sie besonders attraktiv für elektroanalytische Anwendungen. So gelang es auch zum ersten Mal vollständig elektroaktive Multischichten aus Cyt c und Polyanilinsulfonsäure zu präparieren. Dieser Ansatz wurde hier erweitert, um eine analytische Signalkette auf der Basis von Multischichten aus Cyt c und Xanthinoxidase zu entwerfen. Das System bedarf keinen externen Mediator, es hängt jedoch von der in situ Generierung eines vermittelnden Radikals ab und erlaubt daher einen Signaltransfer von Hypoxanthin über ein substratumwandelndes Enzym und Cyt c zur Elektrode. Eine andere Art von Signalketten basiert auf der Assemblierung von Proteinen in Komplexen auf Elektroden in solcher Art und Weise, daß ein direkter Protein-Protein-Elektronentransfer möglich wird. Dieser Ansatz benötigt keinen Redoxmediator in Analogie zu Beispielen aus dem biologischen Signaltransfer. Zu diesem Zweck werden Cyt c und das Enzym Bilirubinoxidase mit einem selbst-assemblierenden Polyelektrolyten auf einer Goldelektrode koimmobilisiert. Obwohl diese zwei Proteine keine natürlichen Reaktionspartner sind, unterstützt die Protein-Architektur einen Elektronentransfer von der Elektrode über mehrere Proteinschichten zu molekularem Sauerstoff und ergibt einen signifikanten katalytischen Reduktionsstrom. Schließlich wird eine neue Strategie beschrieben für eine Selbstassemblierung von Proteinen ohne zusätzlichen Polyelektrolyten - am Beispiel der Kombination von Cyt c mit Sulfitoxidase. Es stellte sich heraus, daß die elektrostatische Wechselwirkung zwischen diesen zwei Proteinen mit ziemlich weit voneinander entfernt liegenden pI-Werten während des Assemblierungsprozesses durch einen Puffer mit geringer Ionenstärke ausreicht um die beiden Biomoleküle nach dem Layer-by-Layer-Prinzip auf einer Elektrode abzuscheiden. Es wird erwartet, daß das entwickelte Konzept von Multiprotein-Assemblaten auf Elektroden weitere Fortschritte bei dem Entwurf von Multischichten und sogar noch komplexeren biomimetischen Signalkaskaden anregen wird und dabei der Vorteil der direkten Kommunikation zwischen Proteinen genutzt wird.

T2K es un experimento de oscilaciones de neutrinos de largo recorrido en el que por primera vez se ha observado la aparición de neutrinos electrónicos en un haz de neutrinos muónicos. Así pues, el único ángulo de mezcla que quedaba por conocer, q13, es medido con gran precisión. el background principal de esta medida es la contaminación de neutrinos electrónicos producida en el haz junto con la componente de neutrinos muónicos. Ésta es una componente irreducible que ha de ser medida y controlada. La componente intrínseca de neutrinos electrónicos es medida antes de las oscilaciones en el detector cercano de T2K confirmando la predicción de la simulación con un precisión del 10%. Se establece que el background de neutrinos electrónicos está bien reproducido y que la principal medida del experimento T2K es exacta. Por otro lado, estudiar la componente de neutrinos electrónicos es interesante para investigar el comportamiento anómalo de algunos experimentos. Estudios en reactores nucleares y resultados en la calibración de experimentos de neutrinos solares con Galio han observado un déficit de neutrinos electrónicos a cortas distancias de la fuente. Este déficit no es compatible con oscilaciones de neutrinos estándar, pero puede ser conciliado en el marco de las oscilaciones, mediante la introducción de un cuarto neutrino con una masa del orden de 1eV². Este nuevo neutrino no sentiría ninguna fuerza del Modelo Estándar y por ello es comúnmente llamado neutrino estéril. Asumiendo que se mezcla con los neutrinos de tipo electrónico, explicaría la desaparición a cortas distancias de los mismos. El detector cercano de T2K se encuentra a una distancia de la fuente óptima para el estudio de oscilaciones de neutrinos estériles ligeros. El modelo más simple de neutrinos estériles con un sólo neutrino adicional es investigado, definiendo intervalos de confianza para los parámetros de oscilación y comparándolos con la literatura.
The T2K experiment is a long baseline neutrino experiment that has observed for first time the appearance of electron-neutrinos in a muon-neutrino beam. Thanks to this analysis, the last unknown neutrino mixing angle q13 is measured with a good precision. The main background to this measurement is the contamination of electron-neutrinos produced in the neutrino beam together with the dominant muon-neutrino component. This is an irreducible component that needs to be measured and controlled. The prediction of this component at SuperKamiokande is based on the constrain of the neutrino flux and cross sections by a muon-neutrino selection at the T2K near detector ND280. To confirm this prediction, we measure the electron-neutrino event rates at ND280 before the oscillations occur, establishing that the electron-neutrino component is correctly reproduced by the simulation at the 10% level. In addition, studying the electron-neutrino component is interesting to investigate the abnormal behaviour of some neutrino experiments. The reactor neutrino experiments as well as the results from calibration with radioactive sources in solar neutrino experiment with gallium have observed a deficit of electron-neutrino at very short distances from the neutrino source. This depletion is not compatible with standard neutrino oscillation, but it can be explained by invoking a fourth neutrino with a mass of the order of 1eV². This neutrino does not feel any force of the Standard Model and hence is called sterile neutrino. Assuming that it mixes with the electron-neutrinos, it would be responsible of the short base-line electron-neutrino disappearance due to neutrino oscillation. The T2K near detector is located at a position short enough to study the light sterile neutrino oscillations. The neutrino model with an additional sterile neutrino apart from the three active species is tested and some constraints to the oscillation parameters are set and compared with the literature.

The aerospace industry is constantly striving to becoming more economical and environmentally friendly. One of many efforts to achieve this is the Lightcam project which in this case is evaluating the use of additive manufacturing in the form of electron beam melting in conjunction with the nickel-based superalloy, Alloy 718. This combination is not fully explored and examined. For this purpose, a demonstrator vane was produced and it was subsequently evaluated in this thesis. The evaluation was performed in as-built condition and was divided in non-destructive testing, evaluation of these methods and metallographic review to confirm the results, and potentially revealing more properties. The non-destructive testing was performed using conventional radiography and computed tomography. Both methods struggled to deliver complete and reliable results, for varying reasons. Radiography could deliver results of the whole vane, but these were impossible to evaluate due to the rough surface created by the electron beam melting process. The computed tomography on the other hand was not affected by the rough surface and produced usable, though not complete, results of the vane. The reason for the computed tomography’s inability to deliver complete results was the material, varying thickness and complex geometry of the vane. As a complement and to verify the results from the non-destructive testing, a metallographic examination was conducted. These tests were conducted with the aim of answering the following three questions:  What non-destructive testing methods are suitable to evaluate Alloy 718 components manufactured with electron beam melting? - Neither radiography nor computed tomography are suitable as a sole evaluation method, for various reasons. All surface dependent methods were deemed unsuitable without testing due to the rough surface. What types of defects and in what quantity can they be found in the produced vane? - Defects found are: Porosity and lack of fusion, both found as internal and partially external and in varying sizes. Where are the defects located? - Pores are mainly found in the center of sections modeled to a 3mm thickness. Lack of fusion was found between build layers in all thicknesses. Apart from these results, hardness was found to vary depending on build height, increasing from the bottom towards the top. Microstructure was also found to vary with the build height, but always consisting of either equiaxed or columnar grains.
Lightcam

T2K is a long baseline neutrino oscillation experiment located in Japan, with a 295km baseline and peak neutrino energy of 0:6 GeV. It is the first off-axis neutrino experiment where the beam is directed approximately 2.5° away from the detectors in order to produce a narrow-band neutrino beam. The experiment was designed to measure the mixing angle θ13 by measuring the neutrino oscillation process vμ -> ve. This measurement relies on the detection of electrons at the far detector from oscillations, and so it is vital to understand the size of the intrinsic ve component of the beam. A measurement of the intrinsic ve component of the T2K beam was performed using the ND280. An analysis that used all of the data taken by the ND280 from February 2010 until March 2011, a total of 1.09 x 10 20 POT, measured 67.7 +- 12.9(stat) +- 5.2(syst) CC ve interactions. The number of events corresponds to a ratio between data and simulation of 0.983+-0.191(stat)+-0.076(syst) and provides strong evidence that the neutrino flux is well simulated. The simulation from the intrinsic ve measurement was then combined with an analysis of vμ interactions in the ND280 to constrain the neutrino flux uncertainties. An idealised study that considered only statistical and flux systematic uncertainties concluded that the intrinsic ve analysis improved the constraint on the flux uncertainties compared to considering only the ND280 vμ analyses, with the effect most prominent at neutrino energies greater than 1 GeV.

Cette thèse est consacrée à la mesure de l'apparition du neutrino électronique avec l'expérience T2K. T2K est une expérience pour la mesure des oscillations de neutrinos installée au Japon. Le faisceau de neutrinos est produit par un accélérateur à JPARC et les neutrinos sont observés avant l'oscillation dans un détecteur proche, ND280, et après l'oscillation dans un détecteur lointain, SuperKamiokande. L'objectif de cette thèse est la mesure, avec le détecteur proche, de la composante intrinsèque de neutrinos électroniques dans le faisceau. Les TPC constituent le détecteur principal utilisé pour cette mesure. La première partie de la thèse décrit la méthode utilisée pour l'identification des particules (PID) : la méthode est basée sur la mesure de la moyenne tronquée de la charge déposée par les particules traversant le milieu gazeux. Les capacités de PID des TPC ont été testées avec des données en faisceau prises à TRIUMF avec un faisceau composé d'électrons, muons et pions ayant une impulsion jusqu'à 400 MeV. L'analyse de ces données confirme que la résolution sur l'énergie déposée dans la TPC est de l'ordre de 7%. Avec les premières données de l'expérience T2K une première mesure de la composante de neutrinos électroniques a été faite. Pour effectuer l'analyse, interactions de neutrinos dans ND280 ont été sélectionnées : cet échantillon est principalement composé par des interactions de neutrinos muoniques car les neutrinos électroniques sont de l'ordre de 1 % du nombre total de neutrinos dans le faisceau. La sélection avec le PID des neutrinos électroniques et muoniques, a permis une première mesure de la composante des neutrinos électroniques dans le faisceau de T2K
This thesis is devoted to the measurement of the electron neutrino appearance with the T2K experiment. T2K is a long baseline neutrino oscillation experiment that is taking data in Japan. The neutrino beam is produced by an accelerator in JPARC and neutrinos are observed in a Near Detector, ND280, before the oscillation and in the far detector, SuperKamiokande, after the oscillation. The aim of this thesis is the measurement of the intrinsic electron neutrino component of the beam with the Near Detector. The main detector used in this measurement is the ND280 TPC. The first part of the thesis describes the method developed for the particle identification in the TPCs: the PID method is based on the measurement of the truncated mean of the charge deposited by the particles crossing the gas. The PID capabilities of the TPCs have been tested analyzing the beam test data: these data have been taken at TRIUMF where we had a beam composed by electrons, muons and pions with momenta up to 400 MeV/c: the analysis of these data confirmed that the resolution on the deposited energy in the TPCs was of the order of 7%. When the first data of the T2K experiment were available, a first measurement of the electron neutrino component in the near detector has been done. To perform the analysis, a sample of neutrino interactions in ND280 was selected: this sample was mainly composed by muon neutrino interactions as the electron neutrino is expected to be 1 % of the total number of neutrinos in the beam. The selection of both, electron and muon neutrinos, allowed a first measurement of the electron neutrino component in the T2K beam

Starting with a muon neutrino (vμ) beam T2K is searching for electron neutrino (ve) ap- pearance in the Far Detector (Super-Kamiokande) and aims to produce the first measure- ment of the neutrino mixing angle e13. Beam contamination of Ve is one of the main background components. The Near Detector, ND280, is optimized for measuring the u; contamination through the reconstruction of Ve interactions. The u; beam contamination is studied in this thesis. The total number of Ve beam events reconstructed in ND280 is 51.2 +21.3 stat. +10.1 sys/ -21.3 stat. -14.4 sys for 1.068 x10 to the power of 20 protons on target, a resu t w lC IS consistent with the Monte Carlo expectations. This result a supplementary statement to the vμ -> 7 Ve oscillation signal observed at Super-Kamiokande during the first year of T2K run, as no significant excess in the expected Ve beam contamination has been observed.

Le projet industriel français MEGaN vise le développement de module de puissance à base de compostant HEMT en GaN. Une des application industrielle concerne l’aéronautique avec une forte contrainte en isolation galvanique (>100 kV/s) et en température ambiante (200°C). Le travail de thèse a été concentré sur une brique module de puissance (bras d’onduleur 650 V 30 A). L’objectif est d’atteindre un prototype de facteur de forme peu épais, 30 cm2 et embarquant l’ensemble des fonctions driver, alimentation de driver, la capacité de bus et capteur de courant phase. Cet objectif implique un fort rendement énergétique, et le respect de l’isolation galvanique alors que la contrainte en surface est forte. Le manuscrit, outre l’état de l’art relatif au module de puissance et notamment celui à base de transistor GaN HEMT, aborde une solution d’isolation de signaux de commande à base de micro-transformateur. Des prototypes de micro-transformateur ont été caractérisés et vieillis pendant 3000 H pour évaluer la robustesse de la solution. Les travaux ont contribué à la caractérisation de plusieurs composants GaN afin de mûrir des modèles pour la simulation circuit de topologie de convertisseur. Au sein du travail collaboratif MEGaN, notre contribution ne concernait pas la conception du circuit intégré (driver de grille), tout en ayant participé à la validation des spécifications, mais une stratégie d’alimentation du driver de grille. Une première proposition d’alimentation isolée pour le driver de grille a privilégié l’utilisation de composants GaN basse-tension. La topologie Flyback résonante avec clamp permet de tirer le meilleur parti de ces composants GaN mais pose la contrainte du transformateur de puissance. Plusieurs technologies pour la réalisation du transformateur ont été validées expérimentalement et notamment une proposition originale enfouissement du composant magnétique au sein d’un substrat polymère haute-température. En particulier, un procédé de fabrication peu onéreux permet d’obtenir un dispositif fiable (1000 H de cyclage entre - 55 ; + 200°C), avec un rendement intrinsèque de 88 % pour 2 W transférés. La capacité parasite d’isolation est réduite par rapport aux prototypes précédent. Deux prototypes d’alimentations à forte intégration utilisent soit les transistors GaN basse tension (2.4 MHz, 2 W, 74 %, 6 cm2), soit un circuit intégré dédié en technologie CMOS SOI, conçu pour l’application (1.2 MHz, 2 W, 77 %, 8.5 cm2). Le manuscrit propose par la suite une solution intégrable de mesure de courant de phase du bras de pont, basé sur une magnétorésistance. La comparaison expérimentale vis à vis d’une solution à résistance de shunt. Enfin, deux prototypes de convertisseur sont décrits, dont une a pu faire l’objet d’une validation expérimentale démontrant des pertes en commutation réduites
The french industrial project MEGaN targets the development of power module based on GaN HEMT transistors. One of the industrial applications is the aeronautics field with a high-constraint on the galvanic isolation (>100 kV/s) and ambient temperature (200°C). The intent of this work is the power module block (3 phases inverter 650 V 30 A). The goal is to obtain a small footprint module, 30 cm2, with necessary functions such as gate driver, gate driver power supply, bulk capacitor and current phase sensor. This goal implies high efficiency as well as respect of the constraint of galvanic isolation with an optimized volume. This dissertation, besides the state of the art of power modules and especially the GaN HEMT ones, addressed a control signal isolation solution based on coreless transformers. Different prototypes based on coreless transformers were characterized and verified over 3000 hours in order to evaluate their robustness. The different studies realized the characterization of the different market available GaN HEMTs in order to mature a circuit simulation model for various converter topologies. In the collaborative work of the project, our contribution did not focus on the gate driver chip design even if experimental evaluation work was made, but a gate driver power supply strategy. The first gate driver isolated power supply design proposition focused on the low-voltage GaN HEMT conversion. The active-clamp Flyback topology allows to have the best trade-off between the GaN transistors and the isolation constraint of the transformer. Different transformer topolgies were experimentally performed and a novel PCB embedded transformer process was proposed with high-temperature capability. A lamination process was proposed for its cost-efficiency and for the reliability of the prototype (1000 H cycling test between - 55; + 200°C), with 88 % intrinsic efficiency. However, the transformer isolation capacitance was drastically reduced compared to the previous prototypes. 2 high-integrated gate driver power supply prototypes were designed with: GaN transistors (2.4 MHz, 2 W, 74 %, 6 cm2), and with a CMOS SOI dedicated chip (1.2 MHz, 2 W, 77 %, 8.5 cm2). In the last chapter, this dissertation presents an easily integrated solution for a phase current sensor based on the magnetoresistance component. The comparison between shunt resistor and magnetoresistance is experimentally performed. Finally, two inverter prototypes are presented, with one multi-level gate driver dedicated for GaN HEMT showing small switching loss performance

In this dissertation, we employ a number of computational methods, including Ab Initio, Density Functional Theory, and Molecular Dynamics simulations to investigate key microscopic parameters that govern charge-transport and charge-generation in single-component and bimolecular charge-transfer organic semiconductors. First, electronic (transfer integrals, bandwidths, effective masses) and electron-phonon couplings of single-component organic semiconductors are discussed. In particular, we evaluate microscopic charge-transport parameters in a series of nonlinear acenes with extended pi-conjugated cores. Our studies suggest that high charge-carrier mobilities are expected in these materials, since large electronic couplings are obtained and the formation of self-localized polarons due to local and nonlocal electron-phonon couplings is unlikely. Next, we evaluate charge detrapping due to interaction with intra-molecular crystal vibrations in order to explain changes in experimentally measured electric conductivity generated by pulse excitations in the IR region of a photoresistor based on pentacene/C60 thin film. Here, we directly relate the nonlocal electron-phonon coupling constants with variations in photoconductivity. In terms of charge-generation from an excited manifold, we evaluate the modulation of the state couplings between singlet and triplet excited states due to crystal vibrations, in order to understand the effect of lattice vibrations on singlet fission in tetracene crystal. We find that the state coupling between localized singlet and correlated triplet states is much more strongly affected by the dynamical disorder due to lattice vibrations than the coupling between the charge-transfer singlet and triplet states. Next, the impact of Hartree-Fock exchange in the description of transport properties in crystalline organic semiconductors is discussed. Depending on the nature of the electronic coupling, transfer integrals and bandwidths can show a significant increase as a function of the amount of the Hartree-Fock exchange included in the functional. Similar trend is observed for lattice relaxation energy. It is also shown that the ratio between electronic coupling and lattice relaxation energy is practically independent of the amount of the Hartree-Fock exchange, making this quantity a good candidate for incorporation into tight-binding transport models. We also demonstrate that it is possible to find an amount of the Hartree-Fock exchange that recovers (quasi-particle) band structure obtained from a highly accurate G0W0 approach. Finally, a microscopic understanding of a phase transition in charge-carrier mobility from temperature independent to thermally activated in stilbene-tetrafluoro-tetracyanoquinodimethane crystal is provided.

A l’heure actuelle, suite à une mauvaise utilisation des antibiotiques, nous faisons face à un problème majeur de santé publique. En effet la résistance aux antibiotiques de certaines souches bactériennes rend le traitement des infections très complexe. Dans ce contexte, le présent projet de thèse concerne l'étude d'un complexe d'efflux bactérien capable de transporter des antibiotiques du cytoplasme vers l'extérieur de la cellule. Ce complexe est composé d'un transporteur de la membrane interne appartenant à la Major Facilitator Superfamily (MFS) (EmrB, E. coli multidrug resistance), d'un canal de la membrane externe TolC (Tolerance to Colicin E1) et d'un adaptateur périplasmique (EmrA, E. coli multidrug resistance). Contrairement aux systèmes d'efflux de type RND (tels que AcrAB-TolC), peu de choses sont connues sur le système EmrAB-TolC de type MFS. Il est donc important d'étudier l'ensemble du complexe sur le plan structurale et fonctionnel afin d'identifier les différences entre ces deux types de systèmes d’efflux. L'objectif de mon projet de thèse était d'étudier au moins un complexe EmrAB-TolC d'un point de vue structurale. Ainsi durant mes études, le but était d'isoler le complexe directement des bactéries surexprimant les trois partenaires protéiques. Dans un premier temps, 15 systèmes homologues EmrAB-TolC ont été identifiés et leurs gènes correspondants amplifiés à partir de l'ADN génomique de différentes bactéries à Gram négatif. Parmi les gènes des 15 systèmes, les gènes codant pour les systèmes d’E. coli et de V. cholerae ont été étudiés plus en détail. Les vecteurs d'expression codaient pour des marqueurs fluorescents pour la mesure des niveaux d'expression de différentes protéines et pour l'étude de la formation des complexes. Dans un premier temps, les différents niveaux d'expression des protéines (EmrB-mRFP1 et EmrA-sfGFP) ont été étudiés pour plusieurs souches d'expression d'E. coli en mesurant les niveaux de fluorescence rouge et verte et par Western blot (anti-His, Myc et Strep pour EmrB, EmrA et TolC). La souche d'E. coli C41(DE3) était la mieux adaptée pour la co-expression d’EmrAB-TolC. Dans un deuxième temps, la méthodologie FSEC (Fluorescence detection Size Exclusion Chromatography) a été utilisée pour identifier un complexe adapté à l'étude structurale. Ainsi, cette méthode a permis d'observer que le complexe EmrAB-TolC d'E. coli était produit en plus grande quantité que celui de V. cholerae. Le protocole final de co-purification consiste à effectuer une lyse douce des bactéries à l'aide du lysozyme, puis après solubilisation avec le DDM, la purification est débutée par une étape de chromatographie d'affinité Ni2+-NTA suivie d'une étape de chromatographie d'exclusion stérique. Enfin, les fractions contenant les trois partenaires protéiques sont utilisées pour l'échange de détergent par l'amphipol A8-35 avant l'étude structurale par microscopie électronique. Les images de microscopie électronique en coloration négative montrent des objets allongés d'une longueur de 33 nm en vue de côté. Une image moyenne d'EmrAB-TolC montre des similitudes avec celle du complexe AcrAB-TolC observé dans des conditions similaires. Les similitudes concernent les densités caractéristiques de TolC. Des différences ont été trouvées pour la partie inférieure d'EmrAB qui est plus fine que la partie inférieure d'AcrAB. Les densités visibles au-dessus de l'anneau d'amphipol correspondent à EmrA, qui présente une structure en forme de canal comme observé avec AcrA. Le canal semble cependant s'étendre plus loin vers la ceinture d'amphipol. Comme EmrB n'a pas de domaine périplasmique étendu présent dans le cas des protéines RND, ces densités sont donc uniquement attribuées à EmrA. EmrA, de l'autre côté, contacte TolC de manière similaire à l'interaction d'AcrA/MexA avec leurs canaux de la membrane externe respectifs (TolC/OprM) de façon «tip-to-tip»
Currently, due to the misuse of antibiotics, we are facing a major public health problem. The resistance to antibiotics of certain bacterial strains makes the treatment of infections very complex. In this context, the present thesis project concerns the study of a bacterial efflux complex capable of transporting antibiotics from the cytoplasm to the outside of the cell. This complex is composed of an inner-membrane Major Facilitator Superfamily (MFS) transporter (EmrB, E. coli multidrug resistance), a channel of the outer membrane TolC (Tolerance to Colicin E1) and a periplasmic adapter (EmrA, E. coli multidrug resistance). Unlike RND-type efflux systems (such as AcrAB-TolC), little is known about the MFS-type EmrAB-TolC system. It is therefore important to study the entire complex on a structural and functional level, to analyse the marked differences between these two types of transport systems. The goal of my thesis project was to study at least one EmrAB-TolC complex from a structural point of view. For my studies the aim was to isolate the complex directly from bacteria overexpressing the three protein partners. In a first step, 15 homologous EmrAB-TolC systems were identified and their corresponding genes amplified from genomic DNA of different Gram-negative bacteria. Among the genes of the 15 systems, the genes coding for the E. coli and V. cholerae systems were further studied. The expression vectors encoded fluorescent markers for the monitoring of the expression levels of different proteins and for studying the formation of complexes. In a first step, the different protein expression levels (EmrB-mRFP1 and EmrA-sfGFP) were studied for several expression strains of E. coli by measuring the red and green fluorescence levels and by Western blot (anti-His, Myc, and Strep for EmrB, EmrA, and TolC). The E. coli strain C41(DE3) was best suited for co-expression of EmrAB-TolC. In a second step, the FSEC (Fluorescence detection Size Exclusion Chromatography) methodology was used to identify a complex suitable for structural study. Thus this method enabled the observation that the EmrAB-TolC complex of E. coli was produced in higher amount than that of V. cholerae. The final co-purification protocol consists in perfoming a gentle lysis of the bacteria using lysozyme, then after solubilization with DDM, the purification is started by a Ni2+-NTA affinity chromatography step followed by a size exclusion chromatography step. Finally, the fractions containing the three protein partners are used for the detergent-exchange by amphipol A8-35 before the structural study by electron microscopy. Negative stain EM-micrographs displayed elongated objects with a length of 33 nm in side view. An average image of EmrAB-TolC shows similarities to that of the AcrAB-TolC complex observed under similar conditions. Similarities included the characteristic densities of TolC. Whereas differences were found in the lower part of EmrAB which is thinner than the lower part of AcrAB. The densities visible above the amphipol-ring correspond to EmrA, which displays a channel-like structure as in AcrA. The channel however seems to extend further towards the amphipol belt. Since EmrB does not have an extended periplasmic domain as the RND proteins have, these densities are therefore solely assigned to EmrA. EmrA, on the other side, contacts TolC akin to the interaction of AcrA/MexA to their cognate outer membrane channels (TolC/OprM) in a ‘tip-to-tip’ fashion
Aufgrund des Missbrauchs von Antibiotika stehen wir derzeit vor einem großen Problem deröffentlichen Gesundheit. Die Antibiotikaresistenz bestimmter Bakterienstämme macht die Behandlungvon Infektionen sehr komplex.In diesem Zusammenhang befasst sich diese Arbeit mit der Untersuchung eines bakteriellenEffluxkomplexes, der Antibiotika vom Zytoplasma zur Außenseite der Zelle transportieren kann. DieserKomplex besteht aus einem Major Facilitator Superfamily (MFS) Transporter der inneren Membran(EmrB, E. coli multidrug resistance), einem Kanal der äußeren Membran TolC (Tolerance to Colicin E1)und einem periplasmatischen Adapter (EmrA, E. coli multidrug resistance).Im Gegensatz zu Effluxsystemen vom RND-Typ (wie AcrAB-TolC) ist über das EmrAB-TolCSystemvom MFS-Typ wenig bekannt. Es ist daher wichtig, den gesamten Komplex auf struktureller undfunktioneller Sicht zu untersuchen, um die deutlichen Unterschiede zwischen diesen beiden Arten vonEffluxsystemen zu analysieren.Ziel meiner Doktorarbeit war es, mindestens einen EmrAB-TolC-Komplex aus struktureller Sichtzu untersuchen. Ziel meiner Studien war es, den Komplex direkt aus Bakterien, die die dreiProteinpartner überexprimieren, zu isolieren. In einem ersten Schritt wurden 15 homologe EmrAB-TolCSystemeidentifiziert und ihre entsprechenden Gene aus der genomischen DNA verschiedenergramnegativer Bakterien amplifiziert. Unter den Genen der 15 Systeme wurden die Gene, die für die E.coli und V. cholerae Systeme kodieren, weiter untersucht. Die Expressionsvektoren codiertenfluoreszierende Marker zur Untersuchung der Expression verschiedener Proteine und zur Untersuchungder Komplexbildung. In einem ersten Schritt wurden die verschiedenen Niveaus der Proteinexpression(EmrB-mRFP1 und EmrA-sfGFP) für mehrere E. coli Expressionsstämme untersucht durch Messen derroten und grünen Fluoreszenzniveaus und durch Western Blot (Anti-His, Myc und Strep für EmrB, EmrAund TolC). Der Stamm von E. coli C41(DE3) war am besten für die Koexpression von EmrAB-TolC14 geeignet. In einem zweiten Schritt wurde die FSEC-Methode (Fluorescence Detection Size ExclusionChromatography) verwendet, um einen für Strukturuntersuchungen geeigneten Komplex zuidentifizieren. Somit konnte mit dieser Methode festgestellt werden, dass der EmrAB-TolC-Komplex vonE. coli in größerer Menge als der von V. cholerae produziert wurde.Das endgültige Ko-Reinigungsprotokoll besteht darin, eine sanfte Lyse der Bakterien unterVerwendung von Lysozym durchzuführen. Nach der Solubilisierung mit DDM wird die Reinigung durcheinen Ni2+-NTA Affinitätschromatographieschritt gefolgt von einemGrößenausschlusschromatographieschritt gestartet. Schließlich werden die Fraktionen, die die dreiProteinpartner enthalten, für den Detergensaustausch durch Amphipol A8-35 vor derStrukturuntersuchung durch Elektronenmikroskopie verwendet.EM-Aufnahmen mit negativer Kontrastierung zeigten längliche Objekte mit einer Länge von 33nm in Seitenansicht. Ein durch Mittlung der Partikel erhaltenes Bild von EmrAB-TolC zeigt Ähnlichkeitenmit dem des AcrAB-TolC-Komplexes, der unter ähnlichen Bedingungen beobachtet wurde.Ähnlichkeiten schlossen die charakteristischen Dichten von TolC ein. Während im unteren Teil vonEmrAB Unterschiede festgestellt wurden, der dünner ist als der untere Teil von AcrAB. Die über demAmphipolring sichtbaren Dichten entsprechen EmrA, das wie bei AcrA eine kanalartige Strukturaufweist. Der Kanal scheint sich jedoch weiter in Richtung des Amphipolgürtels zu erstrecken. Da EmrBkeine erweiterte periplasmatische Domäne aufweist wie die RND-Proteine, werden diese Dichten daherausschließlich EmrA zugeordnet. Auf der anderen Seite kontaktiert EmrA TolC, ähnlich der Interaktionvon AcrA/MexA mit ihren jeweiligen Außenmembrankanälen (TolC/OprM), von “tip-to-tip”

碩士
國立臺灣大學
數學研究所
99
In statistics, dimension reduction is a process of reducing the number of random variables under consideration, and can be divided into feature selection and feature extraction. Principal component analysis (PCA) belongs to the latter category. Traditional linear techniques for dimensionality reduction like PCA reshapes image matrices into vectors. It leads to vectors in a very high-dimensional space and thus easily suff ers from the curse of dimensionality. Multilinear principal component analysis (MPCA) has the potential to serve the similar purpose for analyzing tensor structure data. MPCA aims to preserve the natural data structure, based on 2D matrices rather than 1D vectors, and searches for low-dimensional multilinear projections. It can decrease the dimensionality in a more stable and efficient way than traditional PCA. MPCA and other tensor decomposition methods have been shown to have good performance in both real data analysis and simulations (Ye, 2005; Lu, Plataniotis and Venetsanopoulos, 2008; Kolda and Bader, 2009; Li, Kim and Altman, 2010). However, there is not much statistical theoretic study of it. In this thesis, we place the MPCA in a statistical framework and investigate its statistical properties, including asymptotic distributions for principal components, associated projections and explained variances. We also apply it to electron microscopy images analysis. Due to the nature of low signal to noise ratio (SNR) of electron microscopy images, an averaging process for similar images is needed for denoising. The k-means algorithm is probably the most commonly used algorithm for clustering. However, we find it not ideal for low SNR electron microscopy images. The k-means algorithm needs quite some manual tuning and care in order to get reasonable clustering results. Here we adopt a self-updating process (SUP) clustering algorithm (Chen and Shiu, 2007) on the MPCA-extracted core tensors to recover the hidden cluster structure.

碩士
輔仁大學
管理學研究所
91
This research is to study the impact on business competition when the industry become more competitive after getting mature and the low-price competition which caused by bad economics environment. Especially, when the business conducting their competitive strategies would depend on resources and capabilities to select the available competitive strategies. Then, the business how to fill up the shortage of resource by strategy planning and drafted to create and develop their strategy advantage. During the past 20 years, the economical development in Taiwan grows speedy. From 2001 onwards, low-priced computer and Asia Financial Storm had slow-down Taiwan Information Industry’s output value to only 11.9% growth and Monitor Industry even become negative growth by –5.2%. Compared to 20% of yearly growth before 1997, we can notice that Taiwan’s business would not continuously keep high growth ratio and profitable if they still focus on the traditional production ability and manufacturing superiorities, their competitiveness could not be maintained anymore. This research expect to take Crystal Oscillator Industry, which is 3C End-Product Maker’s key component suppliers, to study their market network and group cluster, and confer the industrial type and characteristic. Through the case T Company’s inside and outside economic environment analysis to study T Company： How to develop and compose their supply chain? How to draft their available competitive strategy and keep the competition advantages? How to re-examine and create their core capabilities to seek upgrading and re-engineering opportunities and achieve another economical miracle in this business. The research is based on Porter’s Five-Force Analysis model and Grant’s SWOT strategy matrix analysis model to analyze corporate environment and the capability of inner business; we can confer the enterprise effects by corporate competitive strategies. As we known, Taiwan component manufacturer and assembler owned the Flexible-Manufacture, Mass-Production capabilities and the position strategy of OEM only, then they would take the chance to involve international markets and extend the worldwide dominion of component Industry. Also only because their quickly as possible to develop internationalized organization and global planning and management system, they got the chance to keep competitiveness and continue grow-up under such strict competitive environment. In addition, through appropriate strategic association and combining strategy, the business could strengthen their position of in Big-China Area. This research suggest Case Company to go for following strategies: Short term select and adopt Cost-Centralize strategy, the reason is: on-going price-war and promotion-war would compress business’s benefit, so they must use economic scope to get cost advantage; Long term go for Differentiation-Centralize strategy, the reason is: develop specialized and high value-added products would serve high technology company’s new designed needs on thin-small product. This is to attract and raise customer’s satisfactory and loyalty, and most import reason is to eschew the price competition. Since the Crystal industry confronts huge challenge on the corporate strategy and management. We also suggest Case Company must enhance the foundation of value chain from business culture 、business mission、vision、objective and based on customer’s needs to lead business operation strategy, continuously create and develop fitting new products to meet customer needs.

In this work we have developed the method of back-transfoprmation within the Douglas-Kroll-Hess (DKH) framework, which has simplified the picture-change consistent transformation of first-order property operators in the DKH approach, making the implementation feasible. This has enabled us to implement the first all-electron scalar relativistic calculations of hyperfine coupling tensors at DKH2 level. Furthemore we have presented a general, relativistic two-component DFT approach for the unrestricted calculations of electronic g-tensors, based on DKH Hamiltonian. Additionally we have derived the expressions for the evaluation of hyperfine structurs and two-component unrestricted treatment of g-tensor within the Resolution of Identity Dirac Kohn Sham method developed by Stanoslav Komorovsky and Michal Repisky in collaboration with other members of the group of V. G. Malkin. All these approaches have been extensively validated
In dieser Arbeit entwickelten wir ein Rücktransformations-Verfahren, das im Rahmen der relativistischen Douglas-Kroll-Hess (DKH) Methode die Picture-Change-konsistente Transformation von Eigenschaftsoperatoren erster Ordnung vereinfacht. Dies ermöglichte uns, die ersten skalar-relativistischen Allelektronen-Berechnungen von Hyperfinekopplungskonstanten auf DKH2-Niveau zu implementieren. Darüber hinaus entwickelten wir eine allgemeine relativistische zweikomponentige Methode für spin-polarisierte Berechnungen von elektronischen g-Tensoren. Zusätzlich leiteten wir die Gleichungen für die Berechnungen der von Stanislav Komorovsky und Michal Repisky entwickelten Resolution-of-Identity-Dirac-Kohn-Sham-Methode her. Alle diese Verfahren wurden in umfangreichen Studien validiert

The signal transduction pathway of halophilic archaea remains a fascinating example of adaptation to extreme environments. Despite similarities with bacterial taxis systems, its structural and dynamics patterns during signal relay remain debatable. The currently investigated SRII/HtrII phototaxis system of Natronomonas pharaonis shows remarkable similarities with chemoreceptors in its membrane and HAMP domains functioning design. By combining site-directed spin labeling (SDSL) with electron paramagnetic resonance (EPR) spectroscopy we investigate the kinase control domain (i.e. signaling domain) of NpSRII/HtrII both in terms of dynamic and structural properties. Our data, as provided by continuous wave and pulse (DEER) EPR techniques, builds on current dynamics based signaling models for HAMP domains (such as the “frozen–dynamic” or two-state equilibrium models). We present an expanded mechanism for signal propagation throughout the signaling domain, where salt and temperature variations trigger subtle shifts in dynamics. Extreme dynamics motional ranges (compact or highly-dynamic) associate with a specific flagellar signaling state, here the kinase-off response, where a more moderate dynamics motion (dynamic) associates with the kinase-on response. Structurally, we reference our data on PML and ND reconstituted NpSRII/HtrII to the EcTsr crystal structure and the NpHtrII homology model. We show that, despite a difference in packing, NpHtrII oligomerizes in a similar manner as EcTsr, even in the absence of stabilizing structures such as the CheA/CheW baseplate. The presence of trimers-of-dimers but also dimers-of-dimers in membrane sheet samples exposes the high affinity with which NpHtrII signaling domains interact. We hope our structural and dynamics details will push further not just drug design but also environmental preservation efforts where taxis systems drive colonization and virulence of pathogens in plants, animals and humans alike.

AcrA is the periplasmic component of an efflux system AcrA-AcrB-TolC, which can expel different classes of antibiotics. AcrB is the inner membrane (IM) pump that utilizes proton-motive force for the active transport, TolC is the outer membrane (OM) channel, and AcrA coordinates the actions of AcrB and TolC, so that substrates are expelled across the two membranes, bypassing the periplasm. It has been proposed that AcrA either provides a static seamless link between AcrB and TolC, or acts like its analogous viral membrane fusion protein (MFP) and actively brings the IM and OM closer for substrate transfer. To better understand the role of AcrA in the efflux mechanism, site-directed spin labeling (SDSL)/EPR (electron paramagnetic resonance) spectroscopy is used to investigate the structure and dynamics of AcrA in solution. My results demonstrated that AcrA is a dynamic protein that undergoes pH-dependent and reversible conformational changes. AcrA contains an interrupted alpha-helical, coiled-coil domain flanked by a pair of beta-stranded lipoyl motifs, and my SDSL/EPR analysis revealed that the pH-induced conformation change mainly involves the coiled-coil and the lipoyl domains. In addition, I found that each AcrA monomer folds into an intra-molecular hairpin and AcrA monomers oligomerize with their coiled-coil hairpins aligned in parallel. Unlike the pH-induced conformational rearrangement of a viral MFP, change in pH alters both intra- and inter-molecular interaction along the coiled-coil of AcrA without rearranging the hairpin fold. The organization of AcrA protomers and its pH-induced conformational switching are, however, congruent with the TolC coiled-coil hairpins in the iris-like opening of the TolC channel. Together, my studies suggest that rather than being a passive structural linkage between AcrB and TolC, AcrA plays an active role mediating the drug efflux. The reported AcrA dynamics provides new insights into the AcrA-TolC interactions for the channel opening during the efflux process.