Ce travail de recherche pluridisciplinaire a consisté en l'étude de cellules photovoltaïques organiques à base de nouveaux copolymères à blocs de type rigide-flexible. L'idée était de proposer une alternative aux mélanges donneur/accepteur, dont la morphologie en film est très difficile à contrôler, en élaborant de nouveaux matériaux conjugués capables de s'auto-organiser et de créer une nano-structuration de la couche active, permettant ainsi d'optimiser certains paramètres du processus photovoltaïque (dissociation de l'exciton, conduction des charges vers les électrodes). La première étape a consisté à développer une synthèse simplifiée et versatile de copolymères constitués d'un bloc conjugué donneur (poly(3-hexylthiophène), d'un bloc flexible polystyrène, et d'un accepteur d'électron (C60). La seconde étape a consisté à caractériser ces matériaux originaux en tant que couche active ou compatibilisants dans des dispositifs photovoltaïques organiques et ainsi montrer leur potentiel. / This multidisciplinary work deals with the study of organic photovoltaic cells based on new rod-coil block copolymers. The aim was to replace donor/acceptor blends which are currently limited by poor control over their thin-film morphology. It was expected that the new materials may self-assemble to give a nano-structuration of the active layer, and thereby optimize the principal physical photovoltaic processes, namely exciton separation and conduction of charge-carriers through the film to the electrodes. A versatile and simplified synthesis of rod-coil copolymers consisting of a donor conjugated block [poly(3-hexylthiophene], a flexible block (polystyrene) and an electron acceptor (C60) was developed. The characterization of the new materials demonstrated their potential as an active layer or compatibilizer in photovoltaic devices.

Cette thèse présente des développements techniques et méthodologiques visant une alternative viable pour le traitement des cancers digestifs (rectum, œsophage). Par rapport aux méthodes standards de thérapie, les ultrasons de contact de haute intensité sous guidage IRM sont une approche moins invasive. L’IRM offre 2 avantages: bonne résolution spatiale et contrôle en temps réel de la température. Cette méthode de traitement demande efficacité et sécurité. Trois prototypes d’antenne RF intégrées à des transducteurs ultrasonores ont été réalisés afin d’améliorer la résolution spatiale et temporelle des images IRM et la précision de la mesure de température. Les antennes intégrées ont montré une meilleure sensibilité par rapport à une antenne extra corporelle standard. Des images IRM haute résolution, anatomiques (voxel0.4x0.4x5 mm3) et de thermométrie (voxel 0.75x0.75x8 mm3, 2s/image) ont été acquises in-vivo.La température a été mesurée, dans un rayon de 20 mm au-delà du ballon, avec un écart type<1°C. Les artéfacts de flux causés par l’eau circulante à l’intérieur du ballon de refroidissement ont pu être projetés hors de la région d’intérêt. L’évolution de la température a été contrôlée automatiquement, à des profondeurs variables, avec un point de contrôle par faisceau. Le contrôleur a montré une grande précision in-vivo (écart type <5%). Le transducteur ultrasonore matriciel permet d’activer successivement plusieurs faisceaux pendant la même dynamique de tir.Des simulations ont été conduites afin de proposer une planification du traitement optimale pour une tumeur désignée. Un nouveau concept de sonde ultrasonore à 256 éléments avec focalisation géométrique naturelle a été proposé. / This thesis presents technical and methodological developments aiming tooffer a viable alternative for the treatment of digestive cancers (rectum and esophagus). Compared to the standard methods of therapy, the high intensity contact ultrasound guided by MRI is a less invasive approach. MRI offers 2 advantages: good spatial resolution, and real-time temperature control. This treatment method requires efficacy and safety. Three prototypes of RF coil integrated with ultrasound transducers were built in order to increase the spatial and temporal resolution ofthe MR images, and the accuracy of the temperature measurement. The integrated coils showed a better sensitivity compared to a standard extracorporeal coil. Anatomical (voxel 0.4x0.4x5 mm3)and thermometry (voxel 0.75x0.75x8 mm3, 2s/image) high resolution MR images were acquired in-vivo. The temperature was measured, within a radius of 20 mm from the balloon, with a standard deviation <1°C. The flow artifacts caused by the water circulating inside the cooling balloon could be shifted out of the region of interest. The temperature evolution was controlled automatically, at different depths, with one control point per beam. The controller showed a good accuracy during in-vivo experiments (standard deviation less than 5%). The phased-arrayultra sound transducer permits the successive activation of multiple beams during the same dynamic of sonication. Simulations were conducted in order to offer an optimal treatment planning for a defined tumor. A new design of ultrasound transducer with 256 elements with revolution symmetry, based on a natural geometrical focalization, was proposed.

L’objectif de la thèse est de développer un dispositif de micro positionnement intégrant à la fois les actionneurs et les capteurs. Un dispositif a été conçu afin de réaliser des déplacements dans les plans sur une course millimétrique. Le dispositif compact ne nécessite pas de système de guidage additionnel et selon le mode d’utilisation de ces moteurs, il est capable de réaliser des translations dans le plan ou des rotations autour d’un axe perpendiculaire au plan. Le dispositif comprend quatre moteurs électromagnétiques linéaires fixés orthogonalement sur une structure en forme de croix. Chaque moteur consiste en une paire de bobines planes entrelacées fixe et une barre ’aimants mobile. Un capteur de déplacement intégré dans la structure en croix permettant de mesurer le déplacement de celle-ci a été conçu et fabriqué. Ce capteur est constitué d’une tête de mesure à fibres optiques placé face à un réseau en silicium réalisé par des techniques de microfabrication. Afin de minimiser les erreurs d’assemblage, la structure en croix a également été micro fabriquée. Le dispositif est capable de réaliser un déplacement de 10 mm et une rotation de ±11° autour de l’axe perpendiculaire au plan du dispositif. La résolution de déplacement du dispositif est de 1,4 µm avec une précision de 31 nm en boucle fermée. Le dispositif peut également atteindre une vitesse de déplacement de 12 mm/s. / The objective of thesis is to develop an integrated micro positioning system for micro applications. A unique micro positioning system design capable to deliver millimeter level strokes with pre-embedded auto guidance feature in micro application has been realized. The design integrates, a stack of orthogonally arranged four electromagnetic linear motors. Each linear motor consists of a fixed planar electric drive coil and mobile permanent magnet array. The optimal design of the system delivers a small footprint size. In addition, to measure and control the displacement, a high resolution compact optical displacement measurement sensor has been designed and fabricated in silicon material using microfabrication technology. Furthermore, a light weight silicon cross structure was fabricated using dry etching technology to reduce components assembly errors. The device is capable to deliver 10 mm displacement stroke with a rotation of ±11° about an axis perpendicular to the plane of the device. The displacement resolution of the device is 1.4 µm with a precision of 31 nm in closed loop control. The device can realize displacement with a speed of 12 mm/s.

This thesis research is concerned with the exploration, design, and validation of novel haptic technologies and signals that feel natural and meaningful in a calm and pleasant way. Our ultimate goal is to expand the possibilities of human-machine interaction by developing a single tactile display and a set of signals through a systematic design approach. It is generally a challenge to evoke a broad range of emotions with vibrotactile stimulation, especially at low signal intensities. During the first part of this thesis research, three types of prototypes were developed and explored using novel haptic technologies. The first was a circular array braille display consisting of eight small six-pin braille modules. The forty-eight pins were arranged in a circular shape to deliver circular tactile information such as time and direction. The second was a braille stick consisting of sixteen six-pin braille modules arranged in a row. The entire display could be easily grasped in the hand so that tactile information can be easily accessible. The third was a 3-by-3 electroactive polymer actuator array driven at high voltages that gives a subtle “tapping” feel on the skin. However, each of the three prototypes suffered from a limited range of expression and was not pursued further.<br> After the initial prototyping efforts, a 2-by-2 vibrotactile display, the palmScape, was conceived and developed. Custom-designed stimulation patterns based on natural phenomena that feel calm and pleasant were designed and implemented with the palmScape. We use text labels to set the context for the vibrotactile icons that attempt to capture and expresses natural metaphors through variations in signal amplitude, frequency, duration, rhythm, modulation, spatial extent, as well as slow movements. Fourteen participants evaluated twenty vibrotactile icons by rating the perceived valence and arousal levels. The twenty stimuli included sixteen custom-designed vibrotactile icons from this thesis research and four reference patterns from two published studies. The results show that our custom-designed patterns were rated at higher valence levels than the corresponding reference signals at similar arousal ratings. Five of the sixteen vibrotactile icons from this research occupied the fourth quadrant of the valence-arousal space that corresponds to calm and pleasant signals. These findings support the validity of the palmScape display and our signal design approach for achieving a calm and pleasant experience and the possibility of reaching a broader range of expressiveness with vibrotactile signals.<br> Future studies will continue with the design of signals that can express a broader range of metaphors and emotions through the palmScape, and build an emotional evaluation database that can be combined with other modalities. Our work can be further expanded to support an immersive experience with naturalistic-feeling vibrotactile effects and broaden the expressiveness of human-computer interfaces in media consumption, gaming, and other communicative application domains.

Neuronavigation and transcranial magnetic stimulation (TMS) are valuable tools in clinical and research environment. Neuronavigation provides visual guidance of a given instrument during procedures of neurological interventions, relative to anatomic images. In turn, TMS allows the non-invasive study of cortical brain function and to treat several neurological disorders. Despite the well-accepted importance of both techniques, high-cost of neuronavigation systems and limited spatial accuracy of TMS in targeting brain structures, limit their applications. Therefore, the aim of this thesis was to i) develop an open-source, free neuronavigation software, ii) study a possible combination of neuronavigation and 3D printing for surgical planning, and iii) construct a multi-channel TMS coil with electronic control of electric field (E-field) orientation. In the first part, we developed and characterized a neuronavigation software compatible with multiple spatial tracking devices, the InVesalius Navigator. The created co-registration algorithm enabled tracking position and orientation of instruments with an intuitive graphical interface. Measured accuracy was similar to that of commercial systems. In the second part, we created 3D printed models from patients with neurological disorders and assessed the errors of localizing anatomical landmarks during neuronavigation. Localization errors were below 3 mm, considered acceptable for clinical applications. Finally, in the last part, we combined a set of two thin, overlapping coils to allow electronic control of the E-field orientation and investigated how the motor evoked responses depend on the stimulus orientation. The developed coil enabled the stimulation of the motor cortex with high angular resolution. Motor responses showed the highest amplitude and lowest latency with E-field approximately perpendicular to the central sulcus. In summary, this thesis provides new methods to improve spatial accuracy of techniques to brain interventions. / A neuronavegação e a estimulação magnética transcraniana (EMT ou TMS, do termo em inglês transcranial magnetic stimulation) têm sido apresentadas como ferramentas valiosas em aplicações clínicas e de pesquisa. A neuronavegação possibilita a localização de instrumentos em relação a imagens anatômicas durante procedimentos de intervenção neurológica. Por sua vez, a EMT permite o estudo não invasivo da função cerebral e o tratamento de doenças neurológicas. Apesar da importância de ambas as técnicas, o alto custo dos sistemas de neuronavegação e a reduzida precisão espacial da EMT em ativar estruturas cerebrais limitam suas aplicações. Sendo assim, o objetivo desta tese foi: i) desenvolver um software de neuronavegação gratuito e de código aberto, ii) estudar a combinação entre neuronavegação e impressão 3D para planejamento cirúrgico, e iii) construir uma bobina de EMT multicanal com controle eletrônico da orientação do campo elétrico (CE). Na primeira parte, desenvolvemos e caracterizamos um software de neuronavegação compatível com vários rastreadores espaciais, o InVesalius Navigator. O algoritmo criado possibilitou o rastreamento de instrumentos por uma interface gráfica intuitiva. A precisão medida foi semelhante à de sistemas comerciais. Na segunda parte, imprimimos modelos 3D de pacientes com patologias neurológicas e avaliamos os erros de localização de marcos anatômicos durante a neuronavegação. Os erros de localização foram inferiores a 3 mm, considerados aceitáveis para aplicações clínicas. Por fim, na última parte, combinamos duas bobinas sobrepostas para controlar eletronicamente a orientação do CE, e investigamos como as respostas motoras evocadas dependem da orientação da corrente. A bobina desenvolvida possibilitou estimular o córtex motor com alta resolução angular. As respostas motoras apresentaram maior amplitude e menor latência para orientação do CE aproximadamente perpendicular ao sulco central. Em suma, esta tese fornece novos métodos para melhorar a precisão espacial de técnicas de intervenção com o cérebro.

En imagerie par résonance magnétique cardiaque et thoracique, les mouvements cardiaques et respiratoires sont enregistrés avec des capteurs tels que les capteurs ECG et les ceintures respiratoires pour synchroniser les acquisitions et pour pratiquer des corrections rétrospectives des images. Le positionnement de ces capteurs augmente le temps de préparation des patients. Il présuppose également la tolérance des patients à être placés dans un espace restreint et déjà contraint par l'antenne radio-fréquence (RF) nécessaire à l'imagerie. Enfin, ces capteurs peuvent diminuer la qualité du signal et donc celle des images. Dans ces travaux, l'antenne RF déjà présente pour la réalisation de l'examen d'imagerie a été elle-même étudiée en tant que capteur de mouvements. Les variations des propriétés électromagnétiques des tissus dues aux mouvements se répercutent de manière directe sur l'impédance de l'antenne. Les variations d'impédance induites par les mouvements ont été étudiées dans des dispositifs utilisant soit des antennes RF volumiques ou des antennes RF surfaciques sur des objets-test animés et sur des sujets sains. Les mouvements respiratoires, cardiaques et les taux sanguins ont été enregistrés avec cette méthode. Puis, les résultats expérimentaux ont été comparés à des simulations électromagnétiques et aux données de la littérature. Une correction de mouvements rétrospective avec l'algorithme GRICS a été appliquée à ces données démontrant la faisabilité de l'utilisation des antennes d'imagerie comme capteurs de mouvements / Especially in cardiac and thoracic magnetic resonance imaging, respiratory motion and heart movement need to be registered using sensors like electrocardiogram or respiratory belts, in order to trigger the image acquisition or perform retrospective corrections. The placement of the sensors extends the patient preparation time, is critical for signal quality and, hence, image quality, and expects patients to tolerate additional sensors besides the imaging coil and space restrictions. In this work, the imaging coil itself was investigated for sensor-less motion registration. Motion-related variations of the electromagnetic properties of tissue have a direct effect on the coil impedance. Lung motion, myocardial-related motion, and vascular blood flow were registered with this method. The experimental findings were compared to electromagnetic simulations and the data gathered by state-of-the-art sensors, and retrospective motion correction with the GRICS algorithm was executed

Chronisch entzündliche Darmerkrankung (CED) bereiten in der Diagnostik durch das meist jüngere Patientenalter, die Tendenz zu Rezidiven im Erkrankungsverlauf, welche häufig den Einsatz diagnostischer Mittel erfordert, und die extraintestinalen Pathologien, die endoskopisch nicht zugänglich sind, Probleme. Durch die bisherigen etablierten Untersuchungsmethoden sind in diesen speziellen Fragestellungen CED nicht immer befriedigend darstellbar. Daher wäre die Einführung der Magnetresonanztomographie (MRT) als Diagnostikalternative von Vorteil. Experimentell soll überprüft werden, wie valide die MRT den pathologischen Befund abbilden kann, ferner die Möglichkeiten einer rechnergestützten, nach festgelegten Algorithmen durchgeführten Auswertung. An einem Kaninchenmodell werden durch Irritantienapplikation chronisch entzündliche Darmerkrankungen simuliert, die resezierten Darmabschnitte mit Wandpathologien im MRT durch eine Mikrospule vermessen und in der Pathologie mikroskopisch untersucht. Am MRT werden die Darmschnitte durch einen konventionellen Editor und einen DICOM-Editor rechnergestützt semiautomatisch ausgewertet. Die transmurale Darmwanddickenmessung zeigt eine gute Korrelation zwischen den maximalen Dickenmessungen der Pathologie und dem konventionellen Editor (rho = 0,850) bzw. der Pathologie und dem DICOM-Editor (r = 0,843). In der Varianzanalyse der nach den Befunden "Normalbefund", "akute Entzündung" und "chronische Entzündung" aufgeschlüsselten maximalen Darmwanddickenbefunde können signifikante Unterschiede zwischen den Gruppen "Normalbefund" und "chronische Entzündung" sowie "akute Entzündung" und "chronische Entzündung" festgestellt werden (jeweils p < 0,01). Dabei enthält die Gruppe der chronischen Entzündungen durchschnittlich die höchsten Darmwanddicken. In einer Analyse der transmuralen Profile liegen die Maxima überwiegend in der dem Lumen zugewandten Seite. Das Kaninchenmodell kann zur Simulation chronisch entzündlicher Darmerkrankungen genutzt werden und ist ausreichend stabil. Höhere Auflösung, kürzere Meßzeiten sowie kostengünstigere MRTs und die Nutzung rechnergestützter Auswertung erweitern die Einsatzmöglichkeiten der bei Problemfällen in der Diagnostik der CED. / Several problems exist in the diagnosis of chronic inflammatory bowel diseases (CIBD). Most patients are young, the diseases have a tendency to recur, which requires repeat diagnostic evaluation, and they may have extraintestinal pathologies, which can not reached by endoscopy. The capabilities of magnetic resonance imaging (MRI) shall be tested by an experiment. CIBD are simulated in a rabbit model by application of an irritating solution. The resected bowel walls with pathologies are measured by using a MRI micro coil system and examined by a pathologist. Bowel sections are evaluated by the conventional editor of the MRI scanner and semiautomatic by fixed algorithms with a DICOM-Editor. The measurement of the bowel thickness shows a good correlation between the maximum thickness of the pathology and the maximum thickness of the conventional editor (rho = 0,850), and , pathology and DICOM-editor (r = 0,843), respectively. In the analysis of variance the measured thickness differed significantly between "normal findings", "acute inflammation" and "chronic inflammation". It differed between the groups "normal findings" and "chronic inflammation" as well as between "acute inflammation" and "chronic inflammation" (each p < 0.01). On average, the group of chronic inflammation contains the highest bowel thickness. In an analysis of the location of signal intensity maximum, the greatest signal was found on the luminal side of the bowel wall. The rabbit model can be used to simulate chronic inflammatory bowel diseases. It is sufficiently reproducible. Higher resolution, shorter measurement periods and more cost-effective MRIs as well as semiautomatic computerized evaluation by fixed algorithms will increase the use of MRI in the case of chronic inflammatory bowel diseases.

Orbitale Erkrankungen stellen für mehrere klinische Fachdisziplinen in Bezug auf Diagnostik und Therapie ein großes Problem dar. Die hochauflösende MRT (HR-MRT) ist in der Lage, eine detailierte Übersicht für die Orbitaanatomie und deren Abnormalitäten zu liefern. Aus diesem Grunde ist diese Studie durchgeführt worden, in der hochauflösenden MRT-Charakteristika von 224 Patienten mit orbitalen Erkrankungen beurteilt worden ist. Die Kriterien der Beurteilung sind: Lokalisation, Größe, Form, Rand, Ausdehnung und Veränderung der Nachbarstrukturen sowie die Signalintensitäten der Erkrankungen. Die Lokalisationskriterien sind sehr nützlich für die Differentialdiagnose orbitaler Erkrankungen der Augenmuskeln, dem extrakonalen und subperiostalen Kompartiment mittels der HR-MRT mit Oberflächenspule. Durch die Zuordnung zu einem Kompartiment kann die Differentialdiagnose grob eingeengt werden. Das subperiostale Kompartiment kann in Sinus, Meningen, orbitalen Knochen und subperiostalen Spaltraum weiter unterteilt werden. Mukozelen und Nasennebenhöhlentumoren sind nur in den Sinus zu finden, sämtliche Keilbeinmeningeome weisen einen Befall der Meningen auf. 83,3% Epidermoide und Dermoide liegen im orbitalen subperiostalen Raum mit einer engen Nachbarschaft zu einer Sutur. Die meisten Muskelbefälle der endokrinen Orbitopathie betreffen den inferioren und medialen geraden Muskel, die Verdickung des Muskelbefalls ist typischerweise nur im Muskelbauch ohne Muskelsehnebefall. Myositiden haben häufiger einen Muskelsehnebefall. Wenn eine Verdickung eines einzelnen Muskels den M. rectus lateralis betrifft, ist die Diagnose einer endokrinen Orbitopathie nicht wahrscheinlich. Rhabdomyosarkome liegen häufig im oberen inneren Quadranten der Orbita. Lymphome liegen meistens im frontalen Anteil des extrakonalen Kompartiment in Nachbarschaft zum Septum orbitale. Für eine weitere Differentialdiagnose sollen die morphologischen Kriterien verwendet werden. Auch die Große, Form und der Rand der orbitalen Erkrankungen können den wichtigen Hinweis zur Differentialdiagnose liefern. Ein reduziertes Muskelvolumen ist bei der Muskelatrophie und dem Trauma mit Muskel Einklemmung gesehen worden. Bei 11 von 128 endokrinen Orbitopathien ist das Volumen normal. Die meiste Erkrankungen gehen mit einer Volumenzunahme einher. Keilbeinmeningeome, Karziome der Nasennebenhöhlen, Rhabdomyosarkome und Lymphome haben große Volumina. Myositis und endokrine Orbitopathie mit Muskelbefall haben meist geringe oder mittlere Volumenzunahmen. Mukozelen, Epidermoid, Dermoid, Metastasen und Hämangiom können in allen Größenstufen gefunden werden. Epidermoide, Dermoide, Mukozelen, Hämangioperizytome, Hämangiome, Rhabdomyosarkome und Metastasen haben meist runde oder elliptische Formen, eine längliche Form wird bei orbitaler Myositis und endokriner Orbitopathie mit Muskelbefall beobachtet. Karzinome der Nasennebenhöhlen, Keilbeinmeningeome, Lymphome, endokrine Orbitopathie mit Fettbefall, Pseudotumoren und Phlegmone zeigen sich unregelmäßige Formen. Epidermoide, Dermoide, Mukozelen, Myositis, endokrine Orbitopathie, Hämangiome und Hämangioperizytome haben meistens einen scharfen Rand. Dagegen weisen Karziome der Nasennebenhöhlen, Lymphome, Keilbeinmeningeome, Rhabdomyosarkome, Metastasen, Pseudotumoren und Phlegmonen undeutliche Ränder auf.Die Verwendung der MRT-Signalintensit?ten zur Diffenrenzierung ist eingeschränkt, weil die meisten Läsionen sehr ähnliche Signalintensitäten zeigen. Es gibt aber einige Läsionen, die aufgrund ihrer Zusammensetzung besondere Signalintensitäten aufweisen, z.B. Blutungen, Melanin (paramagnetisch), Fett, Proteine, Wasser und Nekrosen. Mit einer Kontrastmittelgabe und dem Verhalten des Enhancements kann eine weitere Charakterisierung erfolgen. Bei den Veränderungen der Nachbarstrukturen sind vor allem die Knochenveränderungen am aussagekräftigsten. Epidermoide, Dermoide und Mukozelen sind meist mit Knochendefekten oder Kompressionsveränderungen verbunden, Keilbeinmeningeome stehen eng in Zusammenhang mit Knochenhyperplasien, Nasennebenhöhlenkarzinome sind immer mit Knochendestruktionen verbunden und Frakturen werden nur bei Traumata gesehen. Die raumfordernde Wirkung von Lymphomen ist nicht sichtbar, denn hier zeigt sich eine Diskrepanz zwischen einer oft charakteristischen, ausgedehnten Infiltration und nur einer geringen Verlagerung anderer Orbitastrukturen. Die klinische Krankengeschichte ist auch wesentlich zur Findung der Differentialdiagnose. Alle hier untersuchten Patienten mit Phlegmone und Trauma haben besondere Krankengeschichten. 70% Patienten mit Metastasen haben einen gesicherten Primärtumor in der Krankengeschichte. Alle Patienten mit endokriner Orbitopathie haben in der Anamnese eine Schilddrüsenerkrankung. Von diesen Patienten sind etwa 80% weiblich und 73% zwischen 30 und 60 Jahre alt. Rhabdomyosarkome treten hauptsächlich in der Kindheit auf. Pseudotumoren sprechen schnell und außerordentlich gut auf Steroidtherapien an. Somit kann eine Verbindung von Anamnese und MRT-Bildgebung wertvolle Informationen zur Differentialdiagnose liefern.Zur Differenzierung endokriner Orbitopathie und Myositis ist es nützlich die Lokation des Muskelbefalls (unilateral oder bilateral, Muskelsehne- oder Muskelbauchbefall, Einzelbefall oder Befall mehrerer Muskeln und Bevorzugung bestimmter Muskeln), die Ausdehnung (mit oder ohne Fettbefall), die Verlagerung des Augapfels, MRT-Signalintensitäten und die zeitliche Anamnese zu berücksichtigen. Zur Differenzierung Rhabdomyosarkom und Lymphome sollen das Alter, die Form der Läsionen und der Muskelbefall berücksichtigt werden. Zur Differenzierung zwischen Metastasen und Hämangiome können ihre klinische Krankengeschichte (mit oder ohne frühere Tumoren), der Rand der Läsionen, Muskelbefall und ihr MRT-Signal und das Ausmaß des Enhancements wertvolle Informationen liefern. Die einzige Differenzierungsmöglichkeit zwischen Epidermoid und Dermoid ist die MRT-Signalintensität (fettiger oder wässriger Inhalt der Läsion). Die Lokation ist am wichtigsten für die Differenzierung zwischen Epidermiod und Mukozelen. Für eine Differenzierung zwischen Keilbeinmeningeomen und Masennebenhöhlenkarzinome können ihre Lokationen, ihre Signalintensität, das Kontrasmittelverhalten und Veränderungen der Nachbarstrukturen den wichtigen Hinweis liefern. / The clinical diagnosis of orbital diseases is especially difficult because of the variety of tissues that built up the orbit and present with similar clinical presentation. High-resolution MRI (HR-MRI) has become an important modality for evaluation of the orbital diseases, due to its superb soft tissue resolution, direct multiplanar capability and lack of ionizing radiation. In this study, 224 patients with pathologically identified orbital diseases were evaluated retrospectively. The imaging characteristics of the orbital diseases on HR-MRI with surface coil were assessed. The analyzed criteria were: location, size, shape, margins, extension, adjacent structure, and signal intensity. Locazilation criteria in muscles, extraconal and subperiosteal compartments are very useful in the differential diagnosis of orbital tumors and other disease. If their locations are subdivided into greater detail, the differential diagnosis will be narrowed considerably. For example, the subperiosteal compartment can be subdivided into sinus, meninges, bone and subperiosteal space. Mucocele and carcinoma of nasal sinuses always occur in the nasal sinuses. Sphenoidal meningiomas occur in the meninges, and epidermoid and dermoid are found to 83.3% in the orbital subperiosteal space near the bone sutures and show bony defects or thinning and sclerosis. The most frequently involved muscles in thyroid orbitopathy are the inferior rectus and the medial rectus muscles. Typically, the muscle enlargement involves the muscle belly and spares its tendinous portion. While orbital myositis most frequently involves the lateral rectus muscles in particular the muscles' tendon. When isolated lateral rectus muscle enlargement is present, another etiology rather than thyroid orbitopathy should be considered. Within the extraconal compartment the upper inner quadrant is the most common site of rhabdomyosarcoma. While lymphomas mostly occur in the anterior orbit, posterior to the orbital septum. For further differentiation, morphological criteria can be employed, such as the size, shape, and margin help to make the differential diagnosis. Reduced muscle volume is characteristic in the atrophic muscle. The shortened muscle length occurs in traumas connected with muscle incarcerations. Disease without volume changes may happen in thyroid orbitopathy with the involvement of the muscle or the fat tissue. All the other diseases have a enlarged volume of lesion. The size of Sphenoidal meningioma, carcinoma of nasal sinuses, lymphoma and rhabdomyosarcoma is greatly enlarged. While the size-distribution of mucoceles, epidermoids and dermoids show no difference. But orbital myositis and thyroid orbitopathy have slight to moderate enlarged volume of involved muscles. Concerning the pathology shape mucoceles, dermoids, epidermoids, haemangiomas, and metastases are round or elliptical. The orbital myositis and thyroid orbitopathy with muscle involvement show long shapes. Lymphomas and the thyroid orbitopathy with fat tissue involvement have mostly irregular shapes. The poor-defined margin is often seen in malignant lesions, infections or inflammations, such as a paranasal carcinomas, lymphomas, rhabdomyosarcomas, pseudotumors and phlegmon. While the sharp delineation suggests a benign process, such as a mucocele, dermoid, epidermoid, haemangioma, thyroid orbitopathy and myositis. The use of MRI signal intensity for a differential criterion may be limited, because most diseases have the same signal intensity on MR imaging. Thus it seems to be that signal intensity patterns are usually not specific for the differentiating of diagnose. However, MRI may have some specificity for certain lesions based on signal intensity patterns, especially in those containing hemorrhage, paramagnetic melamin, fat, protein, water, enlarged vessels, and necrosis. With contrast enhancement MRI further contributes to the characterization of various types of lesions within the orbit. It can be made a definitive diagnosis for the dermoid (contains fat), cholesterolcyste, meningioma, lymphangioma (contain hemorrhage), haemangioma, metastasis of melanoma, thyroid orbitopathy with active edema and chronic fibrosis, hematoma and emphysema due to a trauma. Another criterium is the adjacent structure changes. Out of them, the bone changes are very important. Epidermoid, dermoid, and mucocele are often accompanied by bone defects or pressure changes. The sphenoidal meningioma is frequently accompanied by bone hyperplasia. Bone fractures are seen in traumas. Malignant tumors are almost associated with bone destruction when they involve the orbit, e.g., the carcinoma of the nasal sinuses. The effect of occupying space in lymphomas causes mismatch with the size, which often has greater volume. It mostly infiltrates tissue, but it seldom produces mechanical shift to adjacent structures. Clinical history is essential and occasionally it provides a clue that alters the boundary of differential diagnoses and redirects the investigation toward possibilities that had not been previously entertained. Patients with metastases have a definite primary tumor history to 70%. The knowledge of previous malignancy is important for the diagnoses of orbital metastasis. All the patients with thyroid orbitopathy, phlegmon, pseudotumor and trauma have also special clinical histories or symptoms. The rhabdomyosarcoma and capillary hemangioma are the most common orbital tumors in children, while the cavernous hemangioma is the most common orbital vascular tumor in adults. Thyroid orbitopathy occurs with highest prevalence in females with middle age. Orbital pseudotumors usually show a dramatic resolution under steroid therapy. In fact, its final diagnosis is often based on response to steroids. When combined with clinical history and examination, radiologic imaging can provide valuable information regarding the diagnosis and differential diagnoses. For the differentiation of the thyroid orbitopathy and myositis it is useful to take their locations (unilateral or bilateral, tendon involvement or not, single or multiple muscles involvement, and which muscles involvement), sizes, extensions (with or without fat-infiltration), and MRI signal intensities into account; For the differentiation of rhabdomyosarcomas and lymphomas clinical history (ages), the shape of the lesions, and the adjacent structure changes (muscles infiltration) are of diagnostic interest. Clinical history (with or without previous malignancy), the margin of the lesion, their adjacent structure changes (muscles infiltration), and MRI signal intensities help to discriminate between metastases and hemangiomas. The only difference between epidermoid and dermoid is their MRI signal intensities (with or without fat). Location is important to differentiate the epidermiod and mucocele. Locations, adjacent structure changes and MRI signal intensities can provide valuable information to distinguish between sphenoidal meningioma and carcinoma of nasal sinuses. The different shape, margin, adjacent structure change, and MRI signal intensity between the carcinoma of nasal sinuses and mucocele are of diagnostic help.

Diese Dissertation besteht aus zwei Teilen von Studien. Der erste Teil demonstriert die Steuerung der Elektron-Kern-Spin-Systems in II-VI Halbleiter Quantum Dots (QDs) durch elektrische Ströme über Mikrospulen. Mikrometer-große Leiterschleifen sind auf der Oberseite von Heterostrukturen mit geladenen CdSe/ZnS QDs hergestellt worden. Eine Strominjektion erzeugt magnetische Felder im Bereich von einige 10 mT, welche stark genug sind, um die Hyperfeinwechselwirkung in CdSe QDs modulieren zu können. Der Durchmesser des Spulen im Mikrometer-Bereich ermöglicht die Generation von schnellen Feld transienten im Bereich von wenigen ns. Mit diesen Vorteilen der Mikrospulen werden die Steuerungs des Spins der residenten Elektronen sowie das Auslesen des Kernspinzustandes durch elektrische Impulse nachgewiesen. Der zweite Teil befasst sich mit der Ladungsträger-Spindynamik in ZnO Quantum Well (QW) Strukturen und Epitaxieschichten, die mittels des optischen Übergang von negativ geladenen Exzitonen X− beziehungsweise des am neutralen Donator gebunden Exziton D0X untersucht werden. Der Loch-Spin kann direkt über die zirkular polarisierten Photolumineszenz der beiden Komplexe zurückverfolgt werde. Die Spin-Relaxationszeit von QW und Epiplyer verfolgt werden. Der Spin des Donatorelektronens wird über die Ausbleichung des Spin-selektive Anregungprozesses nachgewiesen. Es werden longitudinale Loch-Spinrelaxationszeiten von 80 bis 140 ps für D0X und X− gefunden. Deutlich längere longitudinalen Elektronen-Spin-Relaxationszeiten in Bereich von mehreren 100 ns werden gefunden, wenn die Hyperfeinwechselwirkung durch ein geeignetes externes Magnetfeld unterdrückt wird. Eine Feldstärke von 2 mT ist groß genug. Dies zeigt den extrem kleinen Wert des Overhauser-Feldes in ZnO auf, der durch die sehr begrenzte Anzahl von magnetischen Kernen in Wechselwirkung mit dem Elektronen innerhalb des Volumens des Donators verursacht wird. / This work is composed of two parts of studies. The first part represents an electron-nuclear spin control in II-VI semiconductor quantum dots (QDs) by electrical currents via micro coils. Micrometer single turn coils are fabricated on top of heterostructures with charged CdSe/ZnSe QDs. Current injection creates magnetic fields in the range of some 10 mT which is strong enough to modulate the hyperfine interaction in CdSe. The micrometer-range diameter of coil allows for generation of fast field transient in the range of few ns. Using these advantages of micro coils, local control of the resident electron spin as well as read out of the nuclear spin state are demonstrated by electrical pulses. The second part presents charged carrier spin dynamics in ZnO quantum wells and epilayers using the optical transition of the negatively charged exciton X− and the neutral donor bound exciton D0X, respectively. The hole spin can be directly traced by the circular polarized photoluminescence of both complexes. The spin relaxation of the resident electrons and donor electrons is accessed via the bleaching of the spin selective excitation process. Longitudinal hole spin relaxation times of 80 and 140 ps are found for D0X and X−, respectively. Much longer longitudinal electron spin relaxation times in the several 100 ns range are uncovered if the hyperfine interaction is suppressed by a proper external magnetic field. A field strength of 2 mT is large enough proving that the extremely small value of the Overhauser field in ZnO caused by the very restricted number of magnetic nuclei interacting with the electron inside the donor volume.

Este trabalho apresenta uma metodologia de projeto de atuadores eletromagnéticos lineares inovadora para aplicação em sistemas de suspensão semiativa e ativa. A metodologia, apresentada na forma de fluxograma, define critérios para determinar os requisitos de força e curso que um atuador deve desenvolver considerando um sistema mecânico vibratório com um grau de liberdade com excitação harmônica de base quando o método de controle skyhook é aplicado. Um atuador eletromagnético linear de bobina móvel com duplo arranjo de quase-Halbach que apresenta elevada densidade de força, reduzida massa móvel, ausência de força de relutância e baixa ondulação de força é definido como estudo de caso. Um modelo numérico parametrizado em elementos finitos do comportamento eletromagnético de um passo polar do dispositivo é criado e analisado, considerando restrições dimensionais, com os objetivos de projeto definidos como: elevada densidade de força e reduzida ondulação de força com acionamento brushless CA. Com base no modelo de um passo polar do dispositivo, define-se o volume ativo que o mesmo deve apresentar e, a partir deste, todas as dimensões são definidas de forma a atender os requisitos de projeto. Uma vez definidas as dimensões do atuador com base no modelo eletromagnético, realiza-se a modelagem térmica numérica que permite avaliar qual a máxima densidade de corrente elétrica aplicável de forma que a temperatura, estipulada como máxima, nos enrolamentos não seja excedida. Ainda, a distribuição térmica permite determinar a temperatura de operação dos ímãs permanentes que têm curva de operação dependente da temperatura. A partir dos resultados da simulação térmica e do modelo eletromagnético para um passo polar, realizou-se o acoplamento eletromagnético-térmico por meio da correção das propriedades dos ímãs permanentes e aplicando uma densidade de corrente eficaz dependente das dimensões do modelo parametrizado. O modelo acoplado é simulado e analisado, de modo que as dimensões finais do atuador podem ser obtidas atendendo aos mesmos objetivos de projeto previamente mencionados, respeitando os limites de operação térmica. Adicionalmente, são apresentados modelos analíticos do comportamento eletromagnético e térmico do atuador que podem servir de base para implementação da metodologia proposta, se esta for baseada em modelos analíticos, e podem futuramente ser empregados para a aplicação de otimização matemática do dispositivo. Por fim, um protótipo do dispositivo é construído de forma a validar a metodologia proposta. Com este protótipo são realizados ensaios de densidade de fluxo magnético no entreferro, tensão induzida a vazio, força estática e ensaio dinâmicos com o dispositivo instalado em uma bancada de testes de vibrações controladas desenvolvida durante o projeto. Os resultados mostram a eficácia da metodologia proposta, uma vez que os resultados experimentais mostraram boa concordância com os resultados esperados. / This work presents an innovative linear electromagnetic actuator design methodology for application in semi-active and active suspension systems. The methodology, synthesized in a flowchart, sets criteria to determine requirements such as axial force and stroke that an actuator should develop considering a vibration system with one degree of freedom with harmonic base excitation when the skyhook control method is applied. A linear moving-coil electromagnetic actuator with dual quasi-Halbach arrays of permanent magnets that presents high force density, low moving-mass, no reluctance force and low force ripple is defined as a case study. A finite element numerical parameterized model that describes the electromagnetic behavior of one pole pitch of the device is created and analyzed, considering dimensional constraints, with the design objectives defined as: high force density and low ripple of force with brushless AC drive. Based on the model of one pole pitch of the device the active volume and all dimensions are defined in order to meet the design requirements. Once the actuator dimensions are defined, based on the electromagnetic model, a numerical thermal model was constructed, which allows to evaluate the maximum applicable electric current density so that the maximum temperature at the windings is not exceeded. Furthermore, the thermal distribution gives the operating temperature of the permanent magnets, which present performance highly dependent on temperature. With the results of the thermal simulation, the electromagnetic-thermal coupling is performed by correcting permanent magnet properties and by applying a parametric-dependent effective current density. The coupled model is simulated and analyzed so that the final dimensions of the actuator can be obtained with the same design objectives previously mentioned, while respecting thermal operating limits. In addition, the work presents analytical models of the electromagnetic and thermal behavior of the actuator that can be the basis for implementation of the proposed methodology, if it is based on analytical models, and can further be used for the application of mathematical optimization of the device. Finally, a prototype was built to validate the proposed method. Measurements were carried out to assess magnetic flux density in the air gap, open-circuit induced voltage, static force and dynamic tests with the device installed in a test bench that was developed during this work. The results show the effectiveness of the proposed method since experimental results have shown good agreement with the expected results.