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Nogueira, Thereza Christina Monteiro de Lima. "Estresse e convulsões: participação dos opioides endogenos." reponame:Repositório Institucional da UFSC, 1989. http://repositorio.ufsc.br/xmlui/handle/123456789/75592.
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Tese (doutorado) - Universidade de São Paulo. Departamento de Fisiologia e BiofisicaMade available in DSpace on 2012-10-16T02:39:44Z (GMT). No. of bitstreams: 0Bitstream added on 2013-07-16T17:11:53Z : No. of bitstreams: 1 79070.pdf: 3225953 bytes, checksum: ea81b1737299aba3fa4afaa0e98c7d30 (MD5)
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Permanyer, Ugartemendia Ander. "La Participación española en la economía del opio en Asia Oriental tras el fin del Galeón." Doctoral thesis, Universitat Pompeu Fabra, 2013. http://hdl.handle.net/10803/129731.
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El fin del Galeón de Manila supuso un hecho trascendental en la economía de Asia Oriental. En el caso de la Real Compañía de Filipinas, entonces en ocaso, se vio plenamente mermado su acceso a la plata latinoamericana, que era una de sus bazas principales en sus factorías de Calcuta y Cantón. Esto motivó la reorientación de las actividades privadas de los empleados de la Compañía hacia el comercio del opio, coincidiendo con su estallido, con el apoyo financiero de inversores manileños. El presente trabajo identifica y analiza dichas actividades, que están en la raíz de la destacada firma británica Jardine, Matheson & Co., y las sitúa en el conjunto del comercio europeo en Asia, al que los españoles indudablemente hicieron una importante aportación en un momento clave en la evolución de la economía del opio y del conjunto de la historia de la China moderna.The end of the Manila Galleon was a highly influential event for East Asian economy. The activities of the then declining Spanish Royal Philippine Company were deeply affected by such event: the Company was deprived, mainly in its factories in Calcutta and Canton, of one of its most important assets, namely the access to Latin American silver. Thus, the Company’s employees redirected their private activities towards the then booming opium business, with the financial support of Manila investors. This study identifies and analyses these activities, which are in the roots of what later became Jardine, Matheson & Co., and places them in the context of the European trade in Asia, to which the Spanish undoubtedly made a very important contribution in an key period of the opium economy and modern China historical development.
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Berg, Elliott Philip. "High-speed focal plane array camera for mid-infrared impulse photothermal radiometry." Thesis, London South Bank University, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367903.
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Mow-Lowry, Conor. "Opto-mechanical noise cancellation." View electronic text, 2002. http://eprints.anu.edu.au/documents/disk0/00/00/07/65/index.html.
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Thesis (BSc. (Hons))--Australian National University, 2002.Available via the Australian National University Library Electronic Pre and Post Print Repository. Title from title screen (viewed Mar. 28, 2003). "A thesis submitted for the degree of Bachelor of Science with Honours in physics at the Australian National University" "November 2002" Bibliography: p. 73-75.
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Kadlec, Kal, and Kal Kadlec. "Parametric Opto-Mechanical Performance Analysis of Mounted Lenses Under Thermal Loading." Thesis, The University of Arizona, 2017. http://hdl.handle.net/10150/625904.
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Mounting of lenses in opto-mechanical assemblies can create surface figure errors and refractive index changes through thermal and pre-load stresses. As lenses and barrels change in size under temperature changes, the optical performance degrades due to stress and surface deformations. Currently there is no way of determining the effect of these mechanical perturbations on the system wavefront without performing tedious finite element analysis. Most in-depth opto-mechanical analyses involve case-by-case studies with specific designs while previous general studies fail to take into account the complex geometries. The assumptions made by previous general studies ignore the effects of lens shape. These omissions can have a large effect on the stiffness, stress and surface figure error. A parametric model can combine the best of both an in-depth and general study. By parametrizing the model, a simple analysis can be executed for approximating the environmental-mechanical effects on optical performance. This eliminates the time it takes for an opto-mechanical design to be iterated for an optical or mechanical engineer. This tool could be used for early opto-mechanical design or for finite element analysis verification. The parametric model allows the exploration of the broader design study without confining it to a local design space.
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Edoua, Kacou Charles. "Circuits de photo-réception adaptés très faibles bruits et à grande dynamique." Thesis, Paris Est, 2015. http://www.theses.fr/2015PESC1008/document.
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Ce travail s'inscrit dans le cadre d'un projet commun soutenu par la DGA (procédure RAPID), le projet Récepteur Optique Hyperfréquences LArge Bande ou ROHYLAB, dont VectraWave fait parti. Ce travail de thèse s'inscrit dans le domaine de la radio-sur-fibre en particulier au niveau de la réception. Nous nous inscrivons dans le contexte des photorécepteurs faible bruit, le but étant d'optimiser l'interface optique-électrique de ceux-ci tout en garantissant une grande dynamique. Après avoir présenté les avantages de la radio-sur-fibre à savoir : hauts débits, robustesse et encombrements, nous présentons les photorécepteurs et les différents paramètres qui les caractérisent. Cette étape nous permet de les comparer entre eux en les regroupant en fonction des techniques de conception utilisées dans la littérature. Cette étape nous permet d'identifier la technique de conception à utiliser. Nous choisissons de concevoir photorécepteur bande étroite dont on viendra élargir la bande. Nous définissons ensuite les paramètres nécessaires à la comparaison des technologies entre elles afin de justifier le choix de la technologie de transistor à utiliser. Nous étudions le photorécepteur en tant que système afin de mettre en évidence l'importance des paramètres présentés précédemment sur les performances de celui-ci. De cette analyse nous proposons une méthode de conception bande étroite liant l'ensemble des grandeurs. Nous montrons aussi comment estimer les performances limites en fonction de la technologie utilisée pour la photodiode et celle de l'amplificateur. Aussi nous montrons l'expression de cercles à densité équivalente de courant de bruit constants et de cercles à transimpédance constants. A partir de la modélisation théorique du photorécepteur et l'expression théorique des grandeurs caractéristiques, nous proposons la mise en œuvre et l'utilisation des outils présentés au chapitre précédent avec un logiciel de conception assisté par ordinateur. Nous montrons la modélisation de composants opto-microondes dans un environnement de simulation électrique. A l'aide de ces outils nous concevons trois photorécepteurs faible bruit et à grande dynamique dans la bande 2,9 GHz - 3,4 GHz. Les objectifs fixés sont : 300 de transimpédance, 5 pA/pHz. Ces circuits ont été simulés sous l'environnement électrique ADS mais aussi sous l'environnement électromagnétique MOMEMTUM. Les trois circuits présentent des performances records en bruit à de 3 GHz vis à vis de l'état de l'art. La réalisation du deuxième circuit conçu permet la caractérisation des photorécepteurs dans la bande 2,9 GHz - 3,4 GHz. Nous validons ainsi la démarche et proposons un circuit compétitif vis-à-vis de l'état de l'art. Dans une dernière section de cette thèse, nous illustrons le fait que cette méthode peut être exploitée sur d'autres technologies. Nous mettons en avant aussi le fait que l'on peut envisager la conception de photorécepteurs autour de 20 GHz. Nous envisageons aussi l'utilisation d'une inductance active pour réaliser des photorécepteurs accordables en fréquence pour des fréquences bassesThis work is based on a common project support by the DGA, the project ROHYLAB for “wide band opto-microwave receiver” with Vectrawave . This work aim to optimized the optic-electric interface of a receiver in the radio-over-fiber field to design a low noise and high dynamic receiver. After an overview of radio-over-fiber's avantages such as: high data rates, security and security, we presented different photoreceiver and the figure of merit used to caracterized them. This step allow a comparison of the photoreceiver classified by the design topologies used in order to choose which design methodology we will used in this work. In an other hand, the same analysis is done for the transistor technologies. We presented a study of photoreceiver as a system in order to highlight the impact of main caracteritics on its performances. From this analysis allow to show a narrow band design method which link the caracteristics of the photodiode to the transistor's caracteristics. We also present some design tools such as circles of constant equivalent noise current density and circles of constant transimpedance. From the photoreceiver's theoritical model and the expressions of the main caracteristics, we implement the deisgn tools presented in ADS. In this section we also present the opto-microwave components models. Using this tools, we design three photoreceiver with low noise and high dynamics. This photoreceiver's aims to reach 300 Ohms of transimpedance and 5pA/Hz of noise. This circuits are implemented in ADS's eletrical fields and also in MOMENTUM's fields. All of this circuits appears as a competitive one in terms of noise at 3GHz .From the photoreceiver's design, we realized some cicuirts which permit photoreceiver's caracterization in 2.9 GHz - 3.4 GHz bandwidth. This measurements validate our approach and confirm a competitive circuit in term of noise compare to litterature. In a final sectin of this work, we illustrate an extension of this approach on other technologies. We also highlight a design of a photoreceiver at 20 GHz. In the end, we suggest the using of an active inductor to realize switchable frequency photoreceiver in low frequency
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Vila, i. Planas Jordi. "PDMS-based opto uidic systems." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/284136.
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Al llarg de la tesis, diversos elements òptics i fluidics s’han aconseguit integrar en sistemes optofluidics completament funcionals. La integració d’aquests s’ha realitzat fent servir la tècnica de soft-lithography i el PDMS com material constituent per garantir el baix cost i la felxibilitat dels sistemes LOC. Els elements desenvolupats s’han caracteritzat individualment i els LOCs s’han testat i caracteritzat com a eines per a l’analisis bioquímic per sobrepassar problemes actuals.
Es resalta el diseny, optimització, fabricació i caracterització dels elements optics individuals. Els elements òptics es divideixen en dos grups, passius i actius. Els passius són aquells que no necessiten cap font d’energia externa per funcionar. Primerament, els més simples, i.e., lents col·limadores i estructures d’autoalineament, necessàries per crear estructures més complexes.
Aquests elements s’havien publicat prèviament, però l’optimització feta així com el desenvolupament d’estructures auxiliars tot fabricat utilitzant la mateixa tecnologia i sense augmentar el passos necessaris doten els elements d’una gran robustesa i ens permeten crear estructures més complexes. Miralls d’aire i lents s’han combinat per formar divisors de feix. El principal problema dels divisors de feix és la desviació entre la intensitat als canals de sortida. Aquest problema indica que pot haver-hi un desalineament en la posició de les fibres, les lents col·limadores o els miralls d’aire.
Utilitzant variacions de la tecnologia MIMIC un nou element òptic passiu s’ha dissenyat, fabricat i caracteritzat. PDMS dopat amb 3 pigments diferents s’ha utilitzat per crear filtres amb stopbands al llarg de l’espectr visible. Finalment, un element actiu, un emissor integrat, s’ha redissenyat utilitzant software de simulació òptica. Els resultats suggereixen que hi ha volums morts dins l’estructura i per tant, es proposa una reducció de tamany i un canvi de forma.
La integració de molts d’aquests elements més alguns de fluídics es detalla. Primerament, connectors entre mòduls es dissenyen i testegen. L’emissor redissenyat es manufactura i caracteritza. El seu comportament concorda amb les simulacions i suggereig que encara es podria rediu més el volum. Tots els mòduls es fabriquen de dues repliques de PDMS. Cada mòdul és elàstic i pot ser connectat amb els altres en qualsevol substrat, les connexions entre mòduls no són permanents i es poden fer i desfer sense cap coneixement previ sobre microfluidica o LOC. Per tant, el sistema modular té prou flexibilitat per crear LOC a la carta a investigadors sense els coneixements necessaris per crear-los des de zero. Per provar-ho diversos mòduls s’han unit i utilitzat per determinar la concentració de Cristall violeta.
Les lents col·limadores ja reportades s’han integrat monolíticament en un generador de microgotes monodisperses. S’han proposat dues configuracions òptiques per possibilitar les mesures en fluorescència i absorbància de les microgotes. Ambdues s’han testejat i comparat amb el set up previ demostrant resultats equiparables. A més, les configuracions proposades poden detectar gotes no etiquetades, una fet que no era possible amb el set up previ, amb la mateixa precisió i fiabilitat.
Malgrat tot, degut a les nostres lents col·limadores i els equips de lectura, la velocitat de detecció de gotes està limitada a 160 gotes/s. Finalment, la determinació del medi interior de la gota s’ha demostrat experimentalment per primer cop en un sistema optofluidic.
Finalment, s’ha contruit un FCOR comapcte i integrables utilitzant tècniques de soft-lithography i utilitzant únicament PDMS i aire per assegurar baix cost i robustesa. S’han utilitzat phaseguides per crear un FCOR amb un mirall mòbil sense parts mòbils. Aquest LOC és repetitiu i té una llarga durabilitat (no s’aprecia degradació o baixada de rendiment en tot l’espectre visible durant setmanes).
Per últim, FCOR s’ha integrat amb dos LOC reportats amb anterioritat per fer mesures en paral·lel de glucosa i lactat amb una única font de llum.
Un cop calibrat el sistema, el FCOR permet la mesura de glucosa i lactat amb coherència amb resultats previs. Validant, per tant, el FCOR per anàlisis en paral·lel.Along the thesis, several optics and fluidics elements are succesfully integrated in fully functional optouidic systems. Integration of these elements using soft-lithography fabrication technique and PDMS as constituent material ensures low-cost, disposable and flexible LOCs systems. Developed elements are individually characterized and LOCs are characterized and tested as (bio)chemical tools to overcome unsolved issues of the present state of the art in LOC applications. Design, optimization, fabrication and characterization of individual optical elements is outlined. Optical elements have been divided in two categories, passive and active elements. Passive elements are those which do not require an energy source to work. Firstly, the most simple elements, i.e., collimation lenses and self-alignment structures, necessary to create more complex structures. Such elements usually were published previously, but our development and optimization of elements as well as auxiliary structures, e.g., stoppers and self-alignment channels, built using a single technology with no increase of fabrication steps, provide a robust approach to create more complex structures. Air mirrors and lenses are combined to create beam splitters. The major issue of the BS is the deviation of output power between channels. This result suggests that some misalignment in the fibre position, the lens collimation or the waveguide geometry has occurred. Using developed MIMIC variations a new passive optical element are designed, fabricated and characterized. PDMS doped with three different pigments are used to create filters with stopbands along the whole visible spectrum. Finally, an active element, an integrated emitter, is redesigned using TracePro simulation software. Simulation results suggest there are dead volumes inside the emitter chamber. Then, size reduction and shape change is proposed. Integration of many of the these optical plus some fluidic elements is explained. Firstly, different connectors between modules are designed and tested. The previously redesigned integrated emitter are manufactured and characterized. Its behaviour matches with simulations results and suggest a further size reduction is not only possible but also recommendable. All the modules are fabricated from two PDMS replicas. Each module is elastic and can be assembled with other modules in any substrate, modules connections are not permanent and can be plug and unplug with no previous knowledge in microfluidics or LOC. Hence, presented modular system have enough flexibility to create LOC on demand to researchers without the background required to design and manufacture LOC systems from scratch. In order to prove it several modules are tested together in a crystal violet concentration determination. Previously reported collimation lenses are monolithically integrated in a monodisperse microdroplets generator. Two different optical configurations have been proposed in order to make possible fluorescence and absorbance measurement of droplets. Both are tested and compared to previous set up with equivalent results. In addition, proposed configurations can detect unlabelled droplets, a feature that was not possible with the previous set up, with the same precision and reliability. However, due to our collimation lenses and readout equipment, the droplet generation rate is limited to 160 drops/s. Finally, screening of droplet inner medium is experimentally proved for first time in optofluidic system. Afterwards, a compact and integrable fluidically controlled optical router (FCOR) is build using soft-lithographic techniques and made entirely of PDMS and air ensuring low-cost and robustness. Phaseguides, has been exploited to create a FCOR with a movable mirror without mobile parts. The LOC is repetitive, and has a good durability (non appreciable degradation or performance deterioration for weeks, in the whole visible spectrum). Finally, FCOR is integrated in a previously reported LOC performing parallel measurements of glucose and lactate with a single light source. After setup calibration, the FCOR allows parallel measurement of glucose and lactate showing good agreement with previous results. Validating then, the FCOR for parallel analysis.
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Gilchrist, J. R. "Opto-thermal transient emission radiometry." Thesis, University of Strathclyde, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381131.
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Zegmout, Hanae. "Echantillonneur opto-electronique femto seconde." Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAT084.
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Dans un monde de plus en plus connecté, il devient indispensable de trouver des moyens d’augmenter le débit d’informations qu’il est possible de véhiculer et de traiter. Ce besoin impose aux ingénieurs des contraintes plus serrées en termes de bande passante et de fréquence d’horloge des circuits qu’ils conçoivent.Or, les circuits d’horloge en microélectroniques sont limités par leur performance en termes de stabilité de la période d’horloge, i.e., en termes de « gigue d’horloge » ; cette limitation provient du bruit inhérent au circuit des horloges et rend donc le signal échantillonné inexploitable.Un moyen de se libérer de cette contrainte pourrait être de passer par la photonique intégrée. En effet, les horloges optiques, i.e les lasers pulsés, présentent des performances très intéressantes en termes de stabilité ou de gigue en comparaison avec les horloges en microélectroniques: les gigues des horloges optiques sont cinq fois plus faibles que la plus faible gigue d’horloge électronique citée dans la littérature.L’idée principale de cette thèse est de concevoir un circuit d’échantillonnage qui utilise les pulses du laser comme horloge et qui échantillonne un signal électronique. La brique de base du circuit en question est un photoconducteur en Germanium : une résistance en Germanium dont la résistivité varie selon la puissance du signal optique qu’elle reçoit du laser pulsé. Le photoconducteur dans ce cas précis jour le rôle d’un interrupteur piloté par le laser, et connecte l’entrée RF à la capacité d’échantillonnage. Quand l’interrupteur reçoit un pulse de lumière sa résistance chute et le signal RF peut être copié vers la capacité. Dès que le pulse de lumière s’arrête, le photoconducteur en Germanium retrouve sa résistance initiale et déconnecte ainsi l’entrée RF de la capacité qui contient le signal échantillonné.Cette thèse se propose d’étudier la faisabilité d’un tel circuit et la possibilité d’exploiter la performance des lasers en termes de stabilité de l’horloge dans l’échantillonnage d’un signal électrique.Dans le cadre de la thèse, nous avons essayé d’implémenter le circuit de base présenté auparavant et avons rencontré plusieurs défis. D’abord, les valeurs des résistances Off du photoconducteur n’étaient pas assez élevées pour permettre de déconnecter entièrement le signal RF de la capacité d’échantillonnage. Cela est dû à la présence d’un dopage résiduel lié au procédé de fabrication des photoconducteurs. L’utilisation du Germanium implique également que le passage de l’état On à l’état Off du photoconducteur n’est pas instantané, mais est fonction de la durée de vie des porteurs de charge créés suite à l’exposition aux pulses de lumière (de l’ordre de la nanoseconde).Nous avons contourné ces problèmes en utilisant trois méthodes : une nouvelle géométrie des photoconducteurs en Germanium qui permet de maximiser le rapport Roff/Ron (géométrie brevetée), un contre-dopage pour augmenter la résistivité du matériau et finalement un circuit électronique qui permet de re-échantillonner le signal en utilisant une horloge photonique basée sur les pulses du laser. Nous avons également exploré la possibilité de concevoir des horloges photoniques qui présentent une très faible valeur de gigue et dont la longueur du pulse peut être modifiée de manière indépendante de la longueur du pulse laser utilisé pour les générerAs the world becomes more and more connected, the need for higher data throughput becomes increasingly urgent. This implied more creativity from circuit designers to come up with higher bandwidth circuits and faster pace clocks to drive them.However, the traditional microelectronics clock circuits fail short to fulfill the ever-increasing need for higher sampling frequencies because of their inherent noise. The latter renders the sampled data altogether unusable and therefore hinders the efforts towards higher streams of data.Integrated photonics, the optics alternative to microelectronics, may bring an end to this problem. Indeed, when it comes to pulsed lasers, a not that new technology, the optical pulses clocking features a very low noise compared to its microelectronics counterpart, i.e a jitter that is five folds lower than the best literature microelectronics clock.The main idea of this thesis is to design a sampling circuit that uses the laser pulses as a clock, but samples an electronic signal. This circuit design is mainly based on the use of a Germanium photoconductor, i.e, a Germanium resistor that changes its resistance according to the value of the optical signal it receives. This photoconductor plays then the role of a clocked switch and connects the RF input signal to the hold capacitor. When the switch receives a pulse of light, its resistance drops and the signal can be copied to the capacitor, and once the pulse of light is over, the Germanium photoconductor recovers its first resistance value and the input signal node is disconnected from the capacitor that holds the sampled signal.The aim of this thesis is to study the feasibility of such a design and whether or not it allows taking advantage of the very low jitter value of the laser. Within the thesis, we tried to implement the up said design and stumbled upon many challenges. First, the values of the off switch resistance were not high enough to disconnect the hold capacitor from the input node due to the low resistivity of the used Germanium (residual doping). The Germanium implies also that the switching from one resistance value to another is not instantaneous but rather as long as the photo-generated carriers exist, which lasts for at least a nanosecond. We resolved these problems using three methods: a novel geometry of Germanium photoconductors that allows for high Roff/Ron ratios (patented geometry), a counter-doping to increase the resistivity of the material and finally, a re-sampling circuit driven by a photonic clock based on the laser pulses. We also explored the possibility of making very steep-edged clocks with customizable pulse lengths based on the laser pulses
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Soares, Eric. "Syndrome opso-myoclonique et ganglioneurome." Bordeaux 2, 1990. http://www.theses.fr/1990BOR25070.
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Streiff, Matthias Streiff Matthias. "Opto-electro-thermal VCSEL device simulation /." [S.l.] : [s.n.], 2004. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=15464.
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Zheng, Jia. "Opto-Physiological Modelling of Imaging Photoplethysmography." Thesis, Loughborough University, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.519660.
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Russell, Ben. "Modelling of novel opto-electronic devices." Thesis, University of York, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444759.
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Wang, Rong. "Optical interconnects using opto-electronic arrays /." [St. Lucia, Qld.], 2001. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16267.pdf.
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Park, Seongjun. "Opto-mechanical control of nerve growth." Thesis, Massachusetts Institute of Technology, 2015. http://hdl.handle.net/1721.1/100099.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2015.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 45-47).
A variety of biochemical and biophysical cues have been investigated with the goal of promoting regenerative ability of peripheral nerves. Among those neurotrophic factors, topography, and electrical stimulation have been proposed to enhance nerve growth. This thesis explores optogenetic neural stimulation as a means to control neurite growth that promises greater cell-type specificity than commonly used electrical stimulation. Using dorsal root ganglia (DRGs) expressing channelrhodopsin 2 (ChR2) as a test system, I have investigated a broad range of optical stimulation parameters and identified conditions that enhance neurite outgrowth by three-fold as compared to unstimulated controls or wild-type DRGs lacking ChR2. I have also found that optogenetic stimulation of ChR2 expressing DRGs induces directional outgrowth in WT DRGs co-cultured within a 10 mm vicinity of the optically sensitive ganglia. The observed directional increase of neurite growth was correlated to an increased expression of neural growth and brain derived neurotrophic factors (NGF, BDNF). Finally, experiments performed with DRGs seeded within the mechanical guidance channels showed that simultaneous optical and topographic stimulation act synergistically to increase nerve regeneration rate. This thesis illustrates the potential of optogenetics as a tool to study and control growth in specific nerve populations.
by Seongjun Park.
S.M.
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Azorin-Peris, Vicente. "Opto-physiological modelling of pulse oximetry." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/22498.
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Since its conception decades ago, pulse oximetry-the non-invasive measurement of arterial blood oxygen saturation in real-time-has proven its worth by achieving and maintaining its rank as a compulsory standard of patient monitoring. However, the use of oversimplified models to describe and implement the technology has limited its applicability and has had its evolution at a near standstill for the past decade. Currently available technology relies on empirical calibrations that consist of the correlation between simultaneous measurements from pulse oximeters and invasively acquired arterial blood samples from test subjects, mainly because the mathematical models underlying the technology are not sufficiently descriptive and accurate. Advances in knowledge of human tissue optical properties, computing power and sensing technology all contribute to a new realm of expansion for pulse oximetry modelling. This research project aims to develop a methodology for improving optophysiological models of pulse oximetry through the use of a validated Monte Carlo simulation platform for optical propagation in arbitrary geometries. The platform aims to arrive at a model that can predict the widest range of empirical outcomes while maintaining the highest possible level of accuracy. To this end, an empirical platform and a corresponding experimental protocol is developed towards an increasingly repeatable standard, thus providing an empirical output for validation of simulated data. Subsequently, the parameters and coefficients of the optophysiological model at the core of the simulation platform are iterated until a high level of correlation is achieved in their outputs. This gives way to a new approach to the opto-physiological modelling of pulse oximetry.
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Stuchlik, Marek. "Opto-mechanical effect in chalcogenide glasses." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615917.
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Robin, Adrien. "Opto-électronique de boîtes et puits quantiques colloïdaux - Application au photo-transport." Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066490/document.
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Les nanocristaux colloïdaux semi-conducteurs sont des matériaux synthétisés en suspension et dont les propriétés optiques sont ajustables par leur taille. Une fois sous forme de film, il est possible d’effectuer du transport de charges et ainsi obtenir des dispositifs opto-électroniques. Nous avons choisi deux types de nanocristaux présentant des propriétés optiques originales, mais dont le transport est mal connu. Nous l’étudions d’abord dans des films de nanocristaux bidimensionnels, les nanoplaquettes de CdSe, qui sont une réalisation colloïdale de puits quantiques. Nous montrons qu’il est possible d’accroître le gain de photoconduction en passivant les pièges électroniques afin d’augmenter le temps de vie des porteurs photogénérés. Nous tirons également parti de l’extension latérale de ces objets en les déposant sur des électrodes nanométriques de la taille des particules. Cela permet de s’affranchir du transport par sauts tunnel tout en surmontant l’interaction coulombienne entre l’électron et le trou photogénérés. De manière alternative, nous utilisons un canal de graphène comme couche de transport. Combiné aux propriétés optiques bien définies des nanoplaquettes, nous associons ainsi le meilleur des deux mondes. Enfin, nous étudions le transport dans des films de nanocristaux de HgSe. Ces objets étant naturellement dopés après synthèse, ils présentent une transition intrabande dans l’infrarouge moyen. Nous montrons que le dopage peut s’expliquer par la réduction des nanocristaux par l’eau, et qu’il est contrôlable en jouant sur les dipôles de surface induits par les ligands. Cela nous permet finalement d’élaborer un photodétecteur sur un substrat flexibleColloidal semiconducting nanocrystals are solution-grown inorganic particles whose optical properties are size-dependent. By depositing a film of these objects, charge transport become possible and one can obtain optoelectronic devices. We have chosen two types of nanocrystals with original optical properties, but whose transport is poorly understood and requires studying. First, we study it in films of two-dimensional materials, the CdSe nanoplatelets. These are colloidal realization of quantum wells. We show that it is possible to amplify the photoconductive gain by passivating electronic traps, thus increasing the photogenerated carriers lifetime. We also take advantage of the lateral extension of these objects by depositing them on nanoscale electrodes of the size of the particles. This eliminates the hopping transport while overcoming the coulombic interaction between the photogenerated electron and hole. Alternatively, we use a graphene channel as a transport layer. Together with the well defined optical properties of nanoplatelets, we associate the best of both materials. Finally, we study the transport in films of HgSe nanocrystals. Being naturally doped after synthesis, these objects exhibit an intraband transition in the mid-infrared range. We show that the doping can be explained by the water reduction of nanocrystals, and is controllable by varying the ligandsinduced surface dipoles. This allows us eventually to develop a photodetector on a flexible substrate
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Wallace, Chik-Ho Choy. "Modelling and electro-optic quantum-wells modulation devices." Thesis, University of Surrey, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267967.
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Torras, Andrés Núria. "Smart Opto-mechanical actuators for tactile applications." Doctoral thesis, Universitat Autònoma de Barcelona, 2014. http://hdl.handle.net/10803/363930.
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La discapacitat visual és una greu amenaça que limita la capacitat de les persones per comunicar-se. Amb els anys, s’han explorat diverses propostes tecnològiques basades tan en estímuls auditius com tàctils per aportar solucions reals a la gent que pateix aquest tipus de discapacitat. Entre les més rellevants destaquen les tècniques d’audiodescripció i els dispositius Braille basats en actuació piezoelèctrica, que són els que actualment es troben al mercat.
A dia d’avui, al vell mig de la cursa tecnològica, hi ha una demanda creixent de comunicació rica i fluida mitjançant el tacte. Tan és així que la majoria interruptors, botons i tecles de gran part dels dispositius electrònics del nostre entorn estan essent substituïts per pantalles tàctils, afegint barreres físiques i augmentant les dificultats de comunicació de les persones cegues.
Noves generacions de materials, principalment els polímers, han despertat un gran interès en els darrers anys gràcies a les seves atractives propietats, que poden adaptar-se a la carta en funció de les necessitats. De tots ells, els elastòmers de cristalls líquids, LCE, en són un clar exemple. Els LCE tenen la capacitat intrínseca d’auto-organitzar-se a nivell molecular, desencadenant canvis controlats i totalment reversibles en les seves dimensions a escala macroscòpica, en resposta a diversos tipus d’estímuls externs; canvis que poden adaptar-se per desenvolupar actuadors capaços de produir tan esforços mecànics de tracció com d’empenta.
La recerca presentada en aquesta tesi descriu les principals característiques dels LCE des del punt de vista de l’enginyeria i discuteix les seves possibles aplicacions com a actuadors, amb el principal objectiu d’aportar solucions innovadores als actuals sistemes tàctils, a partir del disseny, fabricació i caracterització de diferents actuadors basats en aquests materials i la seva foto-actuació a partir de llum visible. Propostes que combinen tècniques de processament de materials i tecnologia de microsistemes per aportar solucions tecnològiques innovadores cap a una nova generació d’actuadors intel·ligents.La discapacidad visual es una grave amenaza que limita la capacidad de las personas para comunicarse. Con los años. Se han explorado diversas propuestas tecnológicas basadas tanto en estímulos auditivas como en estímulos táctiles para aportar soluciones reales al colectivo que sufre este tipo de discapacidad. Entre las más relevantes destacan las técnicas de audio descripción y los dispositivos Braille basados en actuación piezoeléctrica, que son los que actualmente se encuentran en el mercado. A día de hoy, en medio de la carrera tecnológica, hay una demanda creciente de comunicación rica y fluida a través del tacto. Tanto es así que la mayoría de los interruptores, botones y teclas de gran parte de los dispositivos electrónicos a nuestro alcance están siendo reemplazados por pantallas táctiles, añadiendo barreras físicas y aumentando las dificultades de comunicación de las personas ciegas. Nuevas generaciones de materiales, principalmente los polímeros, han despertado un gran interés en los últimos años gracias a sus atractivas propiedades, que pueden adaptarse a la carta en función de las necesidades. De todos ellos, los elastómeros de cristales líquidos, LCE, son un claro ejemplo. Los LCE tienen la capacidad intrínseca de auto-organizarse a nivel molecular, produciendo cambios controlados y totalmente reversibles de sus dimensiones a escala macroscópica, en respuesta a varios tipos de estímulos externos; cambios que pueden adaptarse a demanda para desarrollar actuadores capaces de producir distintos tipos de esfuerzos mecánicos de tracción. La investigación recogida y presentada en este documento de tesis describe las principales características de los LCE desde el punto de vista de la ingeniería y discute sus posibles aplicaciones cómo actuadores, con el principal objetivo de aportar soluciones innovadoras a los actuales sistemas táctiles, a partir del diseño, fabricación y caracterización de distintos actuadores basados en estos materiales y su foto-actuación a partir de luz visible. Propuestas que combinan técnicas de procesado de materiales y tecnología de microsistemas para aportar soluciones tecnológicas innovadoras hacia una nueva generación de actuadores inteligentes.
Visual disability is a serious threat that limits the persons’ ability to communicate. Over the years several attempts for the development of technologies based on audio and tactile stimuli have been explored to provide real solutions to individuals with this disability. Among them, audio description techniques and Braille devices based on piezoelectric actuation are the most relevant solutions on the market. Nowadays, with all the technological improvements, there is a growing demand for rich communication through touch. Thus switches, buttons and keyboards of most commonly used electrical devices are being replaced by tactile displays, adding new physical barriers and increasing communications difficulties of blind people. New generation of materials, especially soft polymer composites, have been of increased interest in the last few years due to their many attractive properties, which can be tailored on demand to achieve a broad range of requirements. Liquid-crystalline elastomers, LCE, are a clear example. Such materials possess the intrinsic ability to self-organize at molecular level resulting in a controllable and fully reversible change on their dimensions at macroscale in response to applied external stimuli, which can be easily adapted to make actuators producing pulling or pushing forces. The research presented in this thesis describes the main characteristics of LCE materials from engineering point of view and discusses their potential applications as actuators with the main objective to provide innovative solutions towards current tactile available systems, through the design, fabrication and characterization of different actuator approaches based on these interesting elastomeric materials and their photo-induced actuation using visible light. Novel approaches combining material processing techniques and microsystems technology to provide original solutions towards a new generation of smart actuators.
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Foster, Christopher C. "Numerical modeling of opto-electronic integrated circuits." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1994. http://handle.dtic.mil/100.2/ADA292096.
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Thesis (M.S. in Electrical Engineering and M.S. in Applied Physics and Electrical Engineer) Naval Postgraduate School, December 1994.Thesis advisor(s): Phillip E. Pace, A. W. Cooper. "December 1994." Bibliography: p. 95-99. Also available online.
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Höhn, Stefan. "Opto-mechanische Messungen von flüssigkristallinen Azo-Elastomeren." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=97435886X.
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POH, Chung, and chungp@student ecu edu au. "OPTO-VLSI PROCESSING FOR RECONFIGURABLE OPTICAL DEVICES." Edith Cowan University. Computing, Health And Science: School Of Engineering, 2006. http://adt.ecu.edu.au/adt-public/adt-ECU2006.0023.html.
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The implementation of Wavelength Division Multiplexing system (WDM) optical fibre transmission systems has the potential to realise this high capacity data rate exceeding 10 Tb/s. The ability to reconfigure optical networks is a desirable attribute for future metro applications where light paths can be set up or taken down dynamically as required in the network. The use of microelectronics in conjunction with photonics enables intelligence to be added to the high-speed capability of photonics, thus realising reconfigurable optical devices which can revolutionise optical telecommunications and many more application areas. In this thesis, we investigate and demonstrate the capability of Opto-VLSI processors to realise a reconfigurable WDM optical device of many functions, namely, optical multiband filtering, optical notch filtering, and reconfigurable-Optical-Add-Drop Multiplexing (ROADM). We review the potential technologies available for tunable WDM components, and discuss their advantages and disadvantages. We also develop a simple yet effective algorithm that optimises the performance of Opto-VLSI processors, and demonstrate experimentally the multi-function WDM devices employing Opto-VLSI processors. Finally, the feasibility of Opto-VLSI-based WDM devices in meeting the stringent requirements of the optical communications industry is discussed.
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Smith, Paul Carson. "Broadband analog opto-electronic blind source separation." Diss., Connect to online resource, 2005. http://wwwlib.umi.com/dissertations/fullcit/3178354.
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Rajagopalan, Dharmashankar. "Opto-Electronic Processes in SrS:Cu ACTFEL Devices." UKnowledge, 2006. http://uknowledge.uky.edu/gradschool_theses/273.
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The a. c. thin film electroluminescent (ACTFEL) devices are of scientific interest due to their applications in large area, flat panel displays. Of particular interest to the research community is the mechanism of electron transport and luminance in these devices. Toward this end, a physical model and a mathematical model for SrS:Cu ACTFEL Devices were developed and published earlier by our group. The purpose of this thesis is to obtain a qualitative and quantitative match between experiment and theory. A brief summary of the model can be found here [1]. Effects of variation in drive parameters in experimental steady state measurements, and analysis of VIL (Voltage-Current-Luminance) plots for different simulated device and drive parameters are performed. The effects of voltage amplitude, activator concentration, interface energy levels, and critical field for dipole collapse were studied. The plots matched qualitatively in that all major experimental features were produced in the simulated waveforms. The measured and the simulated peak currents are 72.5 mA/cm2 and 66.42 mA/cm2 for VA = 123 V. Experimental and theoretical charge transferred per pulse were 2.75 C/cm2 and 2.26 C/cm2. Peak experimental and simulated luminance values for VA = 123 V were 531 cd/m2 and 49150 cd/m2. Total experimental and simulated luminance values for VA = 123 V case were 6.2 cd/m2 and 561.2 cd/m2 respectively. The large difference is attributed to the loss factors such as optical losses (due to total internal reflection), scattering of electrons by impurities in the bulk phosphor layer, and concentration quenching; these have not been incorporated in the model yet.
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Casswell, Joshua James. "Optical interconnects for opto-electronic data systems." Thesis, Heriot-Watt University, 2003. http://hdl.handle.net/10399/314.
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Charalambous, Andrew. "Opto-mechanical design for large telescope instrumentation." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243313.
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O'Sullivan, Martin Paul. "Opto-electronic properties of novel semiconductory structures." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620935.
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lrti, Natalino. "Es verdad, pero ... Réplica a Giorgo Oppo." IUS ET VERITAS, 2017. http://repositorio.pucp.edu.pe/index/handle/123456789/122784.
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Khreis, Osama M. "Interdiffusion in III-V opto-electronic materials." Thesis, University of Surrey, 1997. http://epubs.surrey.ac.uk/844237/.
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Photoluminescence coupled with repetitive thermal annealing has been used to study the thermal interdiffusion processes in both InGaAs and GaAsSb grown on GaAs substrates. The effect of growth temperature and group-V to group-III flux ratio were studied in InGaAs MQW wafers. The wells in the MQW stack were grown at different temperatures, one of which was grown well below the standard growth temperature to act as a vacancy source in the MQW stack. Due to this vacancy source we have been able to simultaneously measure the In-Ga interdiffusion coefficient, diffusion coefficient for group-III vacancies in GaAs, and the background concentration of these vacancies. It was shown that the interdiffusion at all temperatures is governed by a constant background concentration of vacancies in the material and that this background concentration is the concentration of vacancies in the substrate material. The measured background concentration of vacancies is about 1017 cm-3. This result showed that the vacancy concentrations in GaAs are not at thermal equilibrium concentrations as has been widely assumed. Rather it has been shown to have a value which is "frozen-in", probably at the GaAs crystal growth temperature. The activation energy found for intermixing of InGaAs/GaAs is shown to be governed solely by the activation term for vacancy diffusion which is calculated to have an activation energy of 3.4+/-0.3 eV. These results provide a mechanism to explain the reduced diffusion coefficient under the Ga rich conditions widely reported. The flux ratio was found not to play any significant role in the interdiffusion process. These results can be explained by the diffusion in all cases being governed by a single vacancy-controlled second-nearest-neighbour bopping mechanism. The interdiffusion process on the group-V sublattice in the GaAsSb material system was shown to obey Pick's second law with an activation energy of 2+/-0.3 eV. This result contradicts earlier reports of non-linear diffusion process in this system.
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Lucat, Antoine. "Acquisition opto-numérique de vêtements asiatiques anciens." Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0012.
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La numérisation est un enjeu majeur dans le domaine du patrimoine, permettant d’une part la sauvegarde à long terme des pièces de collections, et d’autre part de les valoriser sous un jour nouveau. En collaboration avec le Musée d’Ethnographie de Bordeaux (MEB), ce travail de thèse se fixe pour objectif de proposer une solution novatrice en terme de numérisation en proposant une réponse à la problématique suivante : comment restituer fidèlement l’apparence d’une pièce de collection, tel que la version numérique soit, à l’oeil, indiscernable du véritable objet ? La taille des objets à numériser ainsi que la résolution nécessaire pour obtenir la qualité souhaitée impliquent de fait une quantité astronomique de mesures à effectuer, formant un véritable défi technique et scientifique. Cette thèse se propose de répondre à cette observation par la réalisation d’un prototype d’acquisition innovant basé image, formé d’un dôme couvert de 1080 LED au sein duquel évolue une caméra sur bras robotisé. Ce travail est d’abord appuyé par un faisceau de recherches préliminaires, s’attardant sur les problématiques théoriques et pratiques attenant à une telle mesure. Cela a notamment permis de mettre en évidence à quel point la diffraction joue un rôle important dans la mesure de BRDF, bien au-delà des critères habituels. Dans ce sens, un nouvel algorithme de traitement des données, métrologiquement viable, a pu être proposé. Appuyé par ces acquis, le prototype de numérisation a pu être conçu, réalisé, calibré et finalement exploité avec succès pour la sauvegarde du patrimoine. Ce nouvel instrument, en constante évolution, jette alors la première pierre de nombreux axes de recherches futurs, tant portés sur l’optimisation du processus de mesure que sur l’exploitation des données généréesDigitization is a major issue of interest in the field of cultural heritage, allowing on the one hand the long-term safeguard of collector’s pieces, and on the other hand to valorize them under a new revelatory way. In collaboration with the Musée d’Ethnographie de Bordeaux (MEB), this thesis work has the objective of proposing an innovative solution in terms of digitization, by answering the following problem : how to faithfully reproduce the appearance of a collector’s piece, such that the digital version is, to the eye, indistinguishable from the real object ? The size of the objects to be digitized as well as the resolution necessary to obtain the desired quality imply an astronomical quantity of measurements to be carried out, forming a real technical and scientific challenge. This thesis proposes to respond to this observation by producing an innovative imagebased acquisition prototype, formed by a dome covered with 1080 LEDs within which a camera on a robotic arm evolves. This work is first supported by a bundle of preliminary research, focusing on the theoretical and practical issues attached to such a measurement. This notably made it possible to highlight to what extent diffraction plays an important role in BRDF measurements, far beyond the usual criteria. In this sense, a new metrologically viable data processing algorithm has been proposed. Supported by these achievements, the digitization prototype has been designed, produced, calibrated and finally successfully used for the safeguarding of the cultural heritage. This new, constantly evolving instrument then lays the foundation stone for many areas of future research, both focused on optimizing the measurement process and on exploiting the generated data
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Horňáková, Veronika. "Měření parametrů optických a opto-elektrických komponent." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2020. http://www.nusl.cz/ntk/nusl-413000.
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This diploma thesis deals with optical and optoelectronic components. The first part describes three selected optical and three optoelectronic components. Optical components include power divider, isolator and circulator. The optoelectronic ones are laser diode, photodetector and modulator. Basic measurement parameters were defined for each component. In the experimental part, four components from different manufacturers were measured. Selected components are power dividers, isolators, circulators and a laser diode. Subsequently, the measured parameters were compared with the catalog values.
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Labram, John Graham. "Ambipolar organic transistors for opto-electronic applications." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9036.
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This thesis is concerned with the development and study of ambipolar organic field-effect transistors (OFETs), with a specific focus on devices and structures that are relevant to opto-electronic processes. After giving an outline of the relevant theory and experimental methods, the thesis is divided into three experimental chapters. In the chapter on organic phototransistors (OPTs), the fabrication of low-voltage bilayer OPTs is carried out using self-assembled monolayer gate dielectrics. By combining two low-voltage OPTs, the output voltage of a so-called photo-inverter was observed to be modulated over a range of 1.5 V with an incident optical power density of 0 to 1.2 mWcm-2. The characteristics of a high-voltage polymer:fullerene blend photo-inverter device are modelled using variable-range hopping and simple circuit models, suggesting that the device operation is dominated by changes in the threshold voltage. In the second experimental chapter the relationship between the morphology of polymer:fullerene blends and the characteristics of OFETs is studied. It is shown that the thermally-induced clustering of fullerenes is manifest as a reduction in electron mobility, due to a reduction in percolating pathways. It is additionally found that higher molecularweight fullerenes require greater annealing temperature and/or times for this process to occur. The final experimental chapter is concerned with polymer:fullerene diffusion processes and the study of such phenomena using bilayer OFETs. A model based upon the diffusion equation and percolation theory is employed to quantify this process. Again, higher molecularweight fullerenes are observed to require greater annealing temperature for similar phenomena to be observed.
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Martínez, Robles David. "La participación española en el proceso de penetración occidental en China: 1840-1870." Doctoral thesis, Universitat Pompeu Fabra, 2007. http://hdl.handle.net/10803/7466.
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Esta tesis se ha centrado en el desarrollo de las relaciones entre China y España en el contexto de penetración occidental en China desde la firma del Tratado de Nanjing (1842) hasta el final de la década de 1860. España fue un actor secundario en este proceso, pero sus relaciones con el imperio Chino muestran que algunas de las suposiciones de la historiografía más clásica sobre el mismo son demasiado limitadas y restringidas.A mediados de siglo XIX España era una nación en crisis y carecía de los recursos necesarios para tomar parte activa en las acciones occidentales en China. No obstante, su presencia en territorio chino le permitió implicarse de manera indirecta en acontecimientos capitales como las guerras del opio o la Rebelión de los Taiping, negociar en términos similares a los empleados por otros países como la Gran Bretaña o Francia por la obtención de un tratado; e incluso un agente español fue escogido por el Zongli yamen para actuar como representante del gobierno chino en un país europeo.
The main focus of this dissertation is the relationship between China and Spain in the context of the process of foreign penetration in China from the signature of the Treaty of Nanjing (1842) to the end of 1860s. Spain was a minor actor in this process, but her relations with the Chinese empire demonstrate that some of the classical historiographical approaches are too narrow and restricted.
In the 19th century, Spain was a nation in crisis and it lacked the resources to take a leading role in the Western imperial actions in China. Nevertheless, the Spanish presence in China allowed that country to get indirectly involved in major events like the Opium Wars or the Taiping Rebellion; Spain also became embroiled in the negotiations for a treaty in the same terms than those used for imperial powers like Great Britain; and still a Spaniard was chosen by the Zongli yamen to act as a representative of the Chinese government in a European country.
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Yue, Zhang. "Opto-Magneto-Electrical Nanoactuators for Wireless Cell Stimulation." Doctoral thesis, Universitat de Barcelona, 2020. http://hdl.handle.net/10803/670924.
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Clinical treatments based on electrical stimulation of excitable cells have been efficacious for a variety of diseases. However, these devices are often limited by their bulkiness, need for wiring electrodes and inability to target specific cells. Implantable devices that can directly convert optical or magnetic energy to localized electrical output to actuate cells are promising alternatives. This thesis focused on the development of opto-electric and magneto-opto-electric nanomaterials for wireless cell stimulation. Currently, the opto-electric stimulators usually require low penetration visible light and high intensities, the magneto-electric stimulators usually provide poor spatial and temporal precision. In this thesis, two types of nanomaterials have been developed to overcome these challenges.
The first nanomaterial was based on Si/Au nanopillars to achieve opto-electric stimulation in the first and second NIR biological windows with ultralow light intensities. We started with the rational design and analysis, the FDTD simulations predicted that Si nanopillars capped by Au nanodiscs exhibited 6-fold enhancement of the light absorption compared with the plain Si wafer, such enhancement is due to the excitation of novel hybrid metal/dielectric resonances. Next, an exhaustive experimental opto-electric-chemical analysis of Si/Au nanostructures was presented. In particular, the short Si/Au nanopillars gave the highest opto-electric performance, achieving a photovoltage of 80 mV at ultralow light intensity of 0.44 µW/mm2, showing a frequency window of 50-200 Hz to maximize the photovoltage and photocurrent. Finally, the biocompatibility of the Si/Au nanostructures was validated by cell viability assays.
The second nanomaterial was composed of arrays of hollow FeGa/ZnO nanodomes integrated onto soft, flexible and biocompatible elastomeric film. The proposed magneto-electric stimulation is based on the magnetostriction of FeGa and the piezoelectricity of ZnO, the opto-electric stimulation is based on the NIR light absorption of FeGa and the pyroelectric response of ZnO. The magnetic behaviour results revealed that the hexagonal-close-packed arrays with 400 nm diameter provided the lowest saturation magnetic field and minimal remanence. The photothermal test showed intense optical heating for light wavelengths of 808 nm and 1064 nm. The biocompatibility was proved by evaluating the bone Saos-2 cells viability.
Therefore, the Si/Au and FeGa/ZnO nanoactuators present new platforms for wireless cell modulation through NIR light and magnetic field, which may be broadly applicable to both fundamental biological studies and clinical therapeutics.Los tratamientos clínicos basados en la estimulación eléctrica de células excitables han sido eficaces y ampliamente utilizados para una variedad de enfermedades. Sin embargo, estos dispositivos a menudo están limitados por su volumen, la necesidad de electrodos con cableado externo y la incapacidad de actuar en células específicas. Los dispositivos implantables que pueden convertir la energía óptica o magnética en estímulos localizados eléctricos o térmicos para activar las células, son alternativas prometedoras. Esta tesis se centró en el desarrollo de nanomateriales opto-eléctricos y magneto-opto-eléctricos para la estimulación celular inalámbrica. Actualmente, los estimuladores opto-eléctricos generalmente requieren luz visible de baja penetración y altas intensidades, y los estimuladores magnetoeléctricos generalmente proporcionan una precisión espacial y temporal deficiente. En esta tesis, se han desarrollado dos tipos de nanomateriales para superar estos desafíos. El primer nanomaterial se basó en nanopilares Si/Au para lograr la estimulación opto-eléctrica en la primera y segunda ventanas biológicas del infrarrojo cercano con intensidades de luz ultrabajas. Las simulaciones teóricas predijeron que los nanopilares de Si coronados por nanodiscos Au exhiben una mejora de 6 veces en la absorción de luz en comparación con la oblea de Si simple. Tal mejora se debe a la excitación de nuevas resonancias híbridas de metal/dieléctrico. A continuación, se presentó un exhaustivo análisis experimental opto-eléctrico-químico de los nanopilares de Si/Au. Los nanopilares cortos de Si/Au dieron el mayor rendimiento opto-eléctrico, logrando un fotovoltaje de 80 mV a una intensidad de luz ultrabaja de 0,44 µW/mm2, que fue 11 veces mayor que la oblea p-n Si simple. La fotocorriente también mostró una mejora sustancial de 2.5 veces, mostrando una combinación de corrientes capacitivas y faradaicas inducidas por la luz que pueden ajustarse con la densidad de los nanopilares Si/Au. Además, los nanopilares cortos de Si/Au mostraron una ventana de frecuencia de 50-200 Hz para maximizar la fotovoltaje y la fotocorriente. Finalmente, la biocompatibilidad de las nanoestructuras Si/Au fue validada por ensayos de viabilidad celular. El segundo nanomaterial estaba compuesto por matrices de nanocúpulas huecas de FeGa/ZnO integradas en una película elastomérica flexible y biocompatible. La estimulación magnetoeléctrica propuesta se basa en la magnetostricción del FeGa y la piezoelectricidad del ZnO. La estimulación optoeléctrica se basa en la absorción de luz infrarroja por el FeGa y la respuesta piroeléctrica del ZnO. Los resultados del comportamiento magnético revelaron que las matrices hexagonales empaquetadas con un diámetro de 400 nm proporcionaron el campo magnético de saturación más bajo y una remanencia mínima. El análisis fototérmico mostró un intenso calentamiento óptico para longitudes de onda de luz de 808 nm y 1064 nm. La biocompatibilidad se demostró evaluando la viabilidad de las células Saos-2 óseas. En conclusión, los actuadores celulares nanoestructurados de Si/Au y FeGa/ZnO constituyen nuevas plataformas para la modulación electrofisiológica inalámbrica mediante luz infrarroja y campo magnético. Mirando hacia el futuro, son prometedores como nanoactuadores inyectables e implantables in vivo debido a las posibles optimizaciones, como la fabricación en sustratos flexibles y la funcionalización de su superficie para su unión a tipos celulares específicos, que podrían ser ampliamente aplicables tanto a los estudios biológicos fundamentales como a terapias clínicas.
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Berrill, Mark Graham. "An integrated opto-fluidic effector for aerospace applications." Thesis, Brunel University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263517.
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Ioannides, Nicos. "Novel opto-electronic and plastic optical fibre sensors." Thesis, London Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287610.
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The design and performance of a novel displacement sensor is investigated both theoretically and experimentally. This is an optical, extrinsic and differential sensor based on the inverse square law and is insensitive to source intensity variations. It can, in principle, be implemented using only opto-electronic components or it can incorporate optical fibres to allow for EMI free and remote operation. The sensor is implemented using Plastic Optical Fibres (POF) as these offer considerable advantages over glass fibres or glass fibre bundles. The sensor head consists of three POFs positioned side by side and displaced from each other parallel to the axis of the sensor head by a separation X, (mm). The middle POF is coupled to a red LED and emits light onto a flat target with the two outer fibres receiving the reflected light from the target and guiding it to two silicon PIN photodiodes. Theoretical investigations on the behaviour of the sensor are presented for ranges between 0 mm and 100 mm, and for targets with different reflectivities. Non-linearities in the form of a spike are shown to exist in the very short ranges resulting in a minimum operational range of about 15 nun Beyond this minimum range the sensor response is linear and depends on the reflectivity of the target, the accuracy of calibration between the two detectors, any offset voltage present in any of the detectors, possible errors on the detected signals and the X, separation which in principle can be used to scale the sensor. Experimental results obtained confirm the long and linear operational range of the sensor (between 15 mm and 90 mm for a mirror target and between 20 mm and 100 mm for a matt white paper target). Likely variations in the source light intensity do not affect the performance and accuracy of the sensor. Measurements performed with various X, separations verify the scalability feature of the sensor in that by increasing X, one can achieve longer operational ranges. Temperature variations up to 40 °c do not affect the linearity of response. Effects arising from angular misalignment of the target and! or the ends of the three POFs are also investigated and could be minimised by rotating the emitting POF. Matt white paper is concluded as the preferred type of target since it offers a longer linear operational range with less stringent alignment requirements as opposed to reflective targets. Operation of the sensor under ambient illumination conditions is demonstrated using suitable electronic circuitry with filtering facilities. The result is a linear operational range of 60 mm with 1 % accuracy with a matt white paper target. An automated version of the sensor under software control is also demonstrated for monitoring large amplitude (0.15 mm - 6 mm), single degree vibrations. The maximum determined frequency of the vibrating surface is about 150 Hz and this is only limited by the target displacement which is close to the resolution limits of this version of the sensor (0.15 mm). This novel sensor offers considerable advantages over other sensors reported in the literature. It is shown to offer a very long and linear operational range in excess of 100 mm, with accuracy better than 1% and resolution better than 0.2 % of range, and currently this performance is only limited by the electronic circuitry used. Overall, the proposed sensor offers a superior sensor head arrangement and performance combination and its cost is expected to be very low. Suggestions for improvements and other applications are offered.
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Schischmanow, Adrian. "Analyse des Straßenverkehrs mit verteilten opto-elektronischen Sensoren." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2005. http://dx.doi.org/10.18452/15364.
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Aufgrund der steigenden Verkehrsnachfrage und der begrenzten Resourcen zum Ausbau der Straßenverkehrsnetze werden zukünftig größere Anforderungen an die Effektivität von Telematikanwendungen gestellt. Die Erhebung und Bereitstellung aktueller Verkehrsdaten durch geeignete Sensoren ist dazu eine entscheidende Voraussetzung. Gegenstand dieser Arbeit ist die großflächige Analyse des Straßenverkehrs auf der Basis bodengebundener und verteilter opto-elektronischer Sensoren. Es wird ein Konzept vorgestellt, dass eine von der Bilddatenerhebung bis zur Bereitstellung der Daten für Verkehrsanwendungen durchgehende Verarbeitungskette enthält. Der interdisziplinäre Ansatz bildet die Basis zur Verknüpfung eines solchen Sensorsystems mit Verkehrstelematik. Die Abbildung des Verkehrsgeschehens erfolgt im Gegensatz zu herkömmlichen bodengebundenen Messsystemen innerhalb größerer zusammenhängender Ausschnitte des Verkehrsraums. Dadurch können streckenbezogene Verkehrskenngrößen direkt bestimmt werden. Die Georeferenzierung der Verkehrsobjekte ist die Grundlage für eine optimale Verkehrsanalyse und Verkehrssteuerung. Die generierten Daten sind Basis zur Findung und Verifizierung von Theorien und Modellen sowie zur Entwicklung verkehrsadaptiver Steuerungsverfahren auf mikroskopischer Ebene. Es wird gezeigt, wie aus der Fusion gleichzeitig erhaltener Daten mehrerer Sensoren, die im Bereich des Sichtbaren und im thermalen Infrarot sensitiv sind, ein zusammengesetztes Abbildungsmosaik eines vergrößerten Verkehrsraums erzeugt werden kann. In diesem Abbildungsmosaik werden Verkehrsdatenmodelle unterschiedlicher räumlicher Kategorien abgeleitet. Die Darstellung des Abbildungsmosaiks mit seinen Daten erfolgt auf unterschiedlichen Informationsebenen in geokodierten Karten. Die Bewertung mikroskopischer Verkehrsprozesse wird durch die besondere Berücksichtigung der Zeitkomponente bei der Visualisierung möglich. Die vorgestellte Verarbeitungskette beinhaltet neue Anwendungsbereiche für geografische Informationssysteme (GIS). Der beschriebene Ansatz wurde konzeptionell bearbeitet, in der Programmiersprache IDL realisiert und erfolgreich getestet.The growing demand of urban and interregional road traffic requires an improvement regarding the effectiveness of telematics systems. The use of appropriate sensor systems for traffic data acquisition is a decisive prerequisite for the efficiency of traffic control. This thesis focuses on analyzing road traffic based on stationary and distributed ground opto-electronic matrix sensors. A concept which covers all parts from image data acquisition up to traffic data provision is presented. This interdisciplinary approach establishes a basis for the integration of such a sensor system into telematics systems. Unlike conventional ground stationary sensors, the acquisition of traffic data is spread over larger areas in this case. As a result, road specific traffic data can be measured directly. Georeferencing of traffic objects is the basis for optimal road traffic analysis and road traffic control. This approach will demonstrate how to generate a spatial mosaic consisting of traffic data generated by several sensors with different spectral resolution. For traffic flow analysis the realisation of special 4D data visualisation methods on different information levels was an essential need. The data processing chain introduces new areas of application for geographical information systems (GIS). The approach utilised in this study has been worked out conceptually and also successfully tested and applied in the programming language IDL.
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Fuentes, Dominguez Rafael. "Metal nanoparticles as nano-sized opto-acoustic transducers." Thesis, University of Nottingham, 2018. http://eprints.nottingham.ac.uk/53281/.
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There has been much interest in the optical and mechanical properties of metal nanostructures and the possibility to use them as very high frequency opto-acoustic transducers. This interest stems from the ability of such devices to work as sources of ultrasound when a short optical pulse is used to thermally excite them producing GHz acoustic waves. This vibrational response can be detected in the time domain (with other short optical pulse) by measuring the changes in the scattered light using a technique called time-resolved pump-probe spectroscopy. In particular, these devices may allow the generation of ultrasound with very high spatial frequencies (short wavelengths and oblique directions) that will enable very high resolution imaging. In this thesis, the use of spherical metal nanoparticles as nano-sized opto-acoustic transducers will be explored by time-resolved pump-probe spectroscopy measurements using solid and core-shell nanoparticles made by a single metal layer and dielectric-metal layers, respectively. Firstly, the study of the optical and mechanical responses of these devices will be studied by analytical and finite element models. This allows one to obtain the absorption/scattering coefficients and vibrational modes of metal nanostructures by solving Mie and Lamb theory, respectively. Then, time-resolved experimental data will be compared with the modelling achieving two main results. Firstly, the possibility of ``turning off'' the detection mechanism of these devices by tuning the probe wavelength without affecting the generation mechanism. Secondly, the development of a size characterisation technique which can obtain the size of individual particles, their size distribution and also, may be able to obtain information about the surrounding medium. Finally, the main novelty of this work will be described showing a new super-resolution imaging/localisation technique. Here, the optical diffraction limit is overcome by resolving several particles inside the optical point spread function by centroiding and differentiating their vibrational frequencies.
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De, Weck Olivier Ladislas 1968. "Multivariable isoperformance methodology for precision opto-mechanical systems." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/29901.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2001.Includes bibliographical references (p. 277-285).
Precision opto-mechanical systems, such as space telescopes, combine structures, optics and controls in order to meet stringent pointing and phasing requirements. In this context a novel approach to the design of complex, multi-disciplinary systems is presented in the form of a multivariable isoperformance methodology. The isoperformance approach first finds a point design within a given topology, which meets the performance requirements with sufficient margins. The performance outputs are then treated as equality constraints and the non-uniqueness of the design space is exploited by trading key disturbance, plant, optics and controls parameters with respect to each other. Three algorithms (branch-and-bound, tangential front following and vector spline approximation) are developed for the bivariate and multivariable problem. The challenges of large order models are addressed by presenting a fast diagonal Lyapunov solver, apriori error bounds for model reduction as well as a governing sensitivity equation for similarity transformed state space realizations. Specific applications developed with this technique are error budgeting and multiobjective design optimization. The goal of the multiobjective design optimization is to achieve a design which is pareto optimal, such that multiple competing objectives can be satisfied within the performance invariant set. Thus, situations are avoided where very costly and hard-to-meet requirements are levied onto one subsystem, while other subsystems hold substantial margins.
(cont.) An experimental validation is carried out on the DOLCE laboratory testbed. The testbed allows verification of the predictive capability of the isoperformance technique on models of increasing fidelity. A comparison with experimental results, trading excitation amplitude and payload mass, is demonstrated. The predicted performance contours match the experimental data very well at low excitation levels, typical of the disturbance environment on precision opto-mechanical systems. The relevance of isoperformance to space systems engineering is demonstrated with a comprehensive NEXUS spacecraft dynamics and controls analysis. It is suggested that isoperformance is a useful concept in other fields of engineering science such as crack growth calculations in structures. The isoperformance approach enhances the understanding of complex opto-mechanical systems beyond the local neighborhood of a particular point design.
by Olivier L. de Weck.
Ph.D.
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Silva, Gabriel Cenato dos Santos. "Interrogação óptica de acelerômetros micro-opto-eletro-mecânicos." Instituto Tecnológico de Aeronáutica, 2013. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2262.
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Este trabalho se insere na área de estudos da detecção interferométrica óptica como forma de interrogação de acelerômetros da vertente tecnológica de sistemas micro-eletro-mecânicos, provenientes do Projeto AcelerAD, financiado pela FINEP, realizado no âmbito do DCTA/IEAv. Acelerômetros são dispositivos capazes de medir acelerações e vibrações, em até três dimensões, às quais é submetido um determinado corpo; sua alta sensibilidade às acelerações é extremamente útil a inúmeras aplicações. Normalmente, o processo de leitura da aceleração é realizado por métodos eletrônicos; contudo, em certas aplicações, é necessário garantir que o processo de obtenção das informações fornecidas pelo acelerômetro seja imune às interferências eletromagnéticas do ambiente de operação. Dessa forma, este trabalho explora a viabilidade de interrogação de acelerômetros por meios ópticos, explorando a natureza interferométrica óptica da topologia estrutural, não intencionalmente concebida para esse propósito, que foi adotada no acelerômetro MEMS desenvolvido no escopo do Projeto AcelerAD.
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Cosgrave, Isabelle Marie. "'White lies' : Amelia Opie, fiction, and the Quakers." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/18686.
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This thesis offers a reconsideration of Amelia Opie’s career as a novelist in the light of her developing religious allegiances over the period 1814-1825 in particular. In twentieth-century scholarship, Opie (1769-1853) was often treated primarily as the author of Adeline Mowbray (1805) and discussed in terms of that novel’s relationship with the ideas of Wollstonecraft and Godwin. Recent scholarship (Clive Jones, Roxanne Eberle, Shelley King and John B. Pierce) has begun a fuller assessment of her significance, but there is still a need for a thorough discussion of the relationship between her long journey towards the Quakers and her commitment to the novel as a moral and entertaining medium. Many scholars (Gary Kelly, Patricia Michaelson, Anne McWhir and others), following Opie’s first biographer Cecilia Lucy Brightwell (1854), have represented Opie as giving up her glittering literary career and relinquishing fiction-writing completely: this relinquishment has been linked to Quaker prohibitions of fiction as lying. My thesis shows that Quaker attitudes to fiction were more complicated, and that the relationship between Opie’s religious and literary life is, in turn, more complex than has been thought. This project brings evidence from a number of sources which have been overlooked or under-utilised, including a large, under-examined archive of Opie correspondence at the Huntington Library, Opie’s last novel Much to Blame (1824), given critical analysis here for the first time, and the republications which Opie undertook in the 1840s. These sources show that Opie never abandoned her commitment to fiction; that her move to the Quakers was a long and fraught process, but that she retained a place in the fashionable world in spite of her conversion. My Introduction gives a nuanced understanding of Quaker attitudes to fiction, and the first chapter exposes the ‘white lies’ of Opie’s first biographer, Brightwell, and their legacy. I then move on to examine Opie’s early works – Dangers of Coquetry (1790), “The Nun” (1795) and The Father and Daughter (1801) – as she flirts with radicalism in the 1790s, and Adeline Mowbray is explored through a Quaker lens in chapter 3. I juxtapose Opie’s correspondence with her Quaker mentor Joseph John Gurney and the celebrated writer William Hayley with her developing use of the moral-evangelical novel – Temper (1812), Valentine’s Eve (1816) and Madeline (1822) – as Opie was increasingly attracted to the Quakers. Chapter 5 analyses Opie’s anonymous novels – The Only Child (1821) and Much to Blame (1824) – alongside her Quaker works (especially Detraction Displayed (1828)) around the time of her official acceptance to the Quakers (1825). The final chapter investigates how Opie balanced her Quaker belonging with her ongoing commitment to fiction, exemplified in her 1840s republications, which I present in the context of her correspondence with publisher friends Josiah Fletcher and Simon Wilkin, and with Gurney. Opie’s ‘white lies’ of social negotiation reveal her difficulties in maintaining a literary career from the 1790s to the 1840s, but her concerted effort to do so in spite of such struggles provides a highly significant insight into the changing religious and literary climates of this long period.
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Heimfarth, Jan. "Silicium-Nanopartikel: Chemische Oberflächenmodifizierung und (opto-)elektronische Eigenschaften." Doctoral thesis, TU Bergakademie Freiberg, 2009. https://tubaf.qucosa.de/id/qucosa%3A22702.
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Die Arbeit befasst sich mit dem chemischen Verhalten von Oberflächen an Siliciumnanopartikeln. Diese stehen in ihrer Reaktivität, aufgrund des großen Verhältnisses Oberfläche zu Volumen, zwischen einzelnen Atomen und ausgedehnten Kristallen. Durch Umsetzung mit unterschiedlich funktionalisierten Molekülen gelingt es, die Oberfläche der Partikel zu modifizieren. Dabei wurde eine neue Möglichkeit gefunden, Si-C-Bindungen auf Si-Oberflächen zu erzeugen.
Die Modifizierung mit Wasserstoff (durch Behandlung mit HF) oder mit Chlor (durch Umsetzung mit Chlorierungsmitteln) schafft neue, synthetisch wertvolle Ausgangssituationen. Darauf aufbauend konnten Alkyl, Alkoxy- und Amingruppen kovalent angeknüpft werden.
Die chemische Modifizierung der Nanopartikel führt zu verändertem Photoleitfähigkeits- sowie Photolumineszenzverhalten. Es wurde ein Vorschlag zur Deutung dieser Effekte entwickelt.
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Schwab, Lucien. "Sonde opto-mécaniques pour la microscopie AFM rapide." Thesis, Toulouse, INSA, 2020. http://www.theses.fr/2020ISAT0016.
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Dans le domaine de la microscopie, le microscope à force atomique (AFM), inventé en 1986, est aujourd’hui toujours basé sur le même concept de sonde de force : le levier. Les performances de l’AFM, et en particulier sa vitesse d'imagerie, sont principalement limitées par ce levier, dont la fréquence de résonance plafonne à quelques MHz. Ce travail de thèse présente un nouveau concept de sonde AFM, une sonde optomécanique (OM), ainsi que les développements sur l’instrument pour exploiter ses performances. En effet, des sondes OM vibrant à plus de 100 MHz sont développées et exploitées dans ce manuscrit. Elles démontrent une limite de détection thermomécanique remarquable de 4.5x1E-17 m/√Hz à température ambiante, inférieure à celle de toute autre sonde AFM, permettant un fonctionnement avec une amplitude de vibration de 10 pm. Cette sonde OM est constituée d'un anneau de silicium suspendu d'un diamètre de 20 µm, agissant à la fois comme un résonateur mécanique et un résonateur optique à mode de galerie. Les deux sont intimement couplés par la forme de l'anneau : lorsque l'anneau vibre dans un mode de respiration, la longueur de la cavité optique varie et sa longueur d'onde de résonance varie autour de la longueur d’onde centrale de 1,55 µm. De nombreuses variantes de sondes OM sont caractérisées pour trouver la conception optimale, conduisant à un gap de couplage évanescent de 100 nm à 200 nm et une largeur de rayons de suspension inférieure à 100 nm. Grâce à une caractérisation approfondie, un phénomène singulier est également mis en évidence : le super-mode. Deux alternatives pour mettre la sonde en vibration sont comparées : l’actionnement capacitif et optique. L'étude de la stabilité et du bruit de la sonde permet d'identifier une source de bruit supplémentaire en actionnement optique. Ensuite, les sondes OM sont intégrées dans un instrument AFM dont chaque composant est spécialement développé, du scanner piézoélectrique à l'acquisition et au traitement des données. À cause d’un verrou technologique de fabrication, la pointe de la sonde OM n’a pas pu être approchée d’une surface : elle ne dépasse pas du substrat sur lequel la sonde est fabriquée. Un levier AFM classique est donc utilisé pour interagir mécaniquement avec la sonde AFM. La bande passante de l'instrument est alors caractérisée en fonctionnement, démontrant une bande passante de boucle de rétroaction de 100 kHz, à l’état de l’art. Enfin, une première pseudo-image est réalisée avec ces sondes, démontrant le fonctionnement complet de l'instrumentIn the field of microscopy, the atomic force microscope (AFM) invented in 1986 was brought little, but nonetheless impressive, incremental developments since then. This instrument’s performances, and in particular imaging speed, are mainly limited by its cantilever-type force probe whose resonance frequency peaks at a few MHz. This thesis work presents a new concept of AFM probe, an optomechanical (OM) one, and custom instrument’s components to exploit its performances. Indeed, the 100+ MHz vibrating OM probes tested in this manuscript demonstrate an exquisite thermomechanical limit of detection of 4.5x1E-17 m/√Hz at room temperature, lower than any other AFM probe detection, and an instrument-limited 10 pm vibration amplitude. This OM probe consists of a suspended silicon ring with a 10 µm radius, acting as a mechanical resonator and a whispering-gallery-mode optical resonator. The two are intimately coupled by the ring shape: when the ring vibrates in a breathing mode, the optical cavity length varies and so does its resonance wavelength around its central value 1.55 µm. Characterization of numerous OM probes with different designs are investigated to find optimal designs, that is a 100 nm to 200 nm evanescent-coupling-gap and spokes width below 100 nm. Through deep characterization, acute phenomenon is also highlighted as the super-mode. Two alternatives to put the probe in vibration are compared: capacitive and optical. Stability and noise study of the probe help identify an additional noise source in optical actuation, that seem to be related to the optical background signal. Each developed component of the AFM instrument is detailed from piezoelectric scanner to data acquisition and processing. Because of a fabrication technological lock, the tip of the OM probe could not approach any surface as it did not protrude from the substrate on which the probe is made. A conventional AFM lever is therefore used to interact mechanically with the AFM probe. The instrument’s bandwidth is then characterized in operation, demonstrating a state-of-the-art 100 kHz feedback-loop bandwidth. Finally, a first pseudo-image is achieved with such probes, demonstrating the whole instrument operation
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Jorge, Filipe. "Récepteurs opto-millimétriques pour télécommunications mixtes fibre-radio." Lille 1, 1999. https://pepite-depot.univ-lille.fr/LIBRE/Th_Num/1999/50376-1999-433.pdf.
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Le débit sans cesse croissant de l'information à transmettre a nécessité la mise en place de nouveaux systèmes de transmissions au sein des télécommunications optiques. Jusqu'à présent, l'introduction de la fibre jusque chez l'abonné semble assujettie au développement de composants optoélectroniques d'extrémités à faible coût. Parallèlement à ces systèmes exclusivement photoniques, on a vu apparaître des systèmes hybrides associant la transmission optique à une transmission par voie hertzienne millimétrique. Cette thèse est consacrée aux photorécepteurs millimétriques à haut rendement de conversion optique-électrique. Les photodétecteurs PIN et phototransistors bipolaires à hétérojonction de type guide d'onde apparaissent comme des composants prometteurs pour ce type d'application. En effet, leur structure guide d'onde permet une dissociation des propriétés électriques et optiques. De plus le phototransistor, de par ses propriétés de photodétection et d'amplification, semble disposer d'excellentes potentialités dans le cadre de systèmes de communication mixtes radio sur fibre.
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Janoš, Minich. "Stohastički dinamički opis ISI vremenskih nizova: Markovljevi modeli." Phd thesis, Univerzitet u Novom Sadu, Fakultet tehničkih nauka u Novom Sadu, 2018. https://www.cris.uns.ac.rs/record.jsf?recordId=107581&source=NDLTD&language=en.
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Cilj: Brzina ispaljivanja neuralnih impulsa u kori velikog mozga je veoma promenljiva što ukazuje da bi Poasonov tačkasti proces mogao da bude pogodan za modelirqnje takvog procesa. Međutim, brojna istraživanja su pokazala da statistika ispaljivanja ne sledi Poasona. Uprkos tome, još uvek se nije iskristalisao ni alternativni mehanizam koji bi opisao generisanje spajkova, ni raspodela koja bi opisala raspodelu intervala između spajkova (ISI). Ključni cilj ove disertacije je statistička analiza koja će omogućiti modelovanje ISI vremenskih nizova snimljenih u različitim delovima kore velikog mozga dok su majmuni rešavali različite probleme.Metoda: Primenjena je robusna neparametarska statistika da bi se odredila funkcija gustine raspodele (PDF) ISI vremenskih nizova. Rezultati su verifikovani butstrep metodom i iskorišćeni za kreiranje Markovljevog modela.Rezultati: Pokazalo se da se raspodela ISI intervala ne može opisati samo jednom funkcijom i da se statistika ne može da poveže isključivo sa već postojećim modelima, uključujući i eksponencijalni. Pokazalo se, zatim, da ISI statistika ne zavisi od regije u kori velikog mozga, niti, unutar jedne regije, od problema koji je budni majmun rešavao. Međutim, ISI mizovi snimani dok je majmun rešavao isti problem ali u različitim vremenskim intervalima nisu statistički slični, što ukazuje na postojanje varijabiliteta u ISI vremenskim nizovima u zavisnosti od problema koji se rešava.Zaključak: Rezultati analize signala ukazuju da je neuralna aktivnost posledica komplesnih generišućih mehanizama sa značajnom međuzavisnošću i da process zavisi od zadatka koji se rešava.Objectives: High variability of neuronal firing patterns in the cerebral cortex points towards spiking activity models based on Poisson point processes. In spite of growing evidence that firing behavior may fail Poisson statistics, an alternate spike generating mechanisms and the resulting inter-spike interval (ISI) distributions have not been clarified yet. The key objective of this thesis is to perform a statistical analysis that would yield a model of ISI time series recorded from different from different cortical areas of awake monkeys performing various behavioral tasks.Methods: A robust and non-parametrical statistics to determine ISI probability density functions (PDF-s) of extracellularly recorded cerebral cortical neurons of behaving macaque monkeys is performed. The results were validated using the bootstrap method. The obtained statistics were used to create a Markov model of ISI time series.Results: It turned out that there is no single ISI distribution, but many, and that the underlying statistics is not associated exclusively to the current established models including the exponential. Distribution of types of ISI statistics obtained from different cortical areas are statistically similar and the same applies to the statistics obtained from the same cortical area by ignoring ongoing behavior. However, particular ISI time series observed during the time epochs of the same behavioral task did not show statistical similarity, suggesting a task dependent variation of spike generating dynamics.Conclusion: In summary, the results indicate that neuronal firing activity is resulted by complex generative mechanisms with significant dependency and that this process is contingent upon the behavior.
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Lamberti, Fabrice-Roland. "Opto-phononic confinement in GaAs/AlAs-based resonators." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC103/document.
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Ces travaux de thèse portent sur la conception et sur la caractérisation expérimentale de résonateurs opto-phononiques. Ces structures permettent le confinement simultané de modes optiques et de vibrations mécaniques de très haute fréquence (plusieurs dizaines jusqu’à plusieurs centaines de GHz). Cette étude a été effectuée sur des systèmes multicouches à l’échelle nanométrique, fabriqués à partir de matériaux semiconducteurs de type III-V. Ces derniers ont été caractérisés par des mesures de spectroscopie Raman de haute résolution. Grâce aux méthodes expérimentales et aux outils numériques développés, nous avons pu explorer de nouvelles stratégies de confinement pour des phonons acoustiques au sein de super-réseaux nanophononiques, à des fréquences de résonance de l’ordre de 350 GHz. En particulier, nous avons étudié les propriétés acoustiques de deux types de résonateurs planaires. Le premier est basé sur la modification adiabatique du diagramme de bande d’un cristal phononique unidimensionnel. Dans le deuxième système, nous utilisons les invariants topologiques caractérisant ces structures périodiques, afin de créer un état d’interface entre deux miroirs de Bragg phononiques. Nous nous sommes ensuite intéressés à l’étude de cavités opto-phononiques permettant le confinement tridimensionnel de la lumière et de vibrations mécaniques de haute fréquence. Nous avons mesuré par spectroscopie Raman les propriétés acoustiques de résonateurs phononiques planaires placés à l’intérieur de cavités optiques tridimensionnelles, de type micropiliers. Enfin, la dernière partie de cette thèse porte sur l’étude théorique des propriétés optomécaniques de micropiliers GaAs/AlAs. Nous avons effectué des simulations numériques par éléments finis, nous permettant d’expliquer les mécanismes de confinement tridimensionnel de modes acoustiques et optiques dans ces systèmes, et de calculer les principaux paramètres optomécaniques. Les résultats de cette étude démontrent que les micropilier GaAs/AlAs possèdent des caractéristiques prometteuses pour de futures expériences en optomécanique, telles que des fréquences de résonance acoustiques très élevées, de hauts facteurs de qualités mécaniques et optiques à température ambiante, ou encore de fortes valeurs pour les facteurs de couplage optomécaniques et pour le produit Q • fThe work carried out in this thesis addresses the conception and the experimental characterization of opto-phononic resonators. These structures enable the confinement of optical modes and mechanical vibrations at very high frequencies (from few tens up to few hundreds of GHz). This study has been carried out on multilayered nanometric systems, fabricated from III-V semiconductor materials. These nanophononic platforms have been characterized through high resolution Raman scattering measurements. The experimental methods and the numerical tools that we have developed in this thesis have allowed us to explore novel confinement strategies for acoustic phonons in acoustic superlattices, with resonance frequencies around 350 GHz. In particular, we have studied the acoustic properties of two nanophononic resonators. The first acoustic cavity proposed in this manuscript enables the confinement of mechanical vibrations by adiabatically changing the acoustic band-diagram of a one-dimensional phononic crystal. In the second system, we take advantage of the topological invariants characterizing one dimensional periodic structures, in order to create an interface state between two phononic distributed Bragg reflectors. We have then focused on the study of opto-phononic cavities allowing the simultaneous confinement of light and of high frequency mechanical vibrations. We have measured, by Raman scattering spectroscopy, the acoustic properties of planar nanophononic structures embedded in three-dimensional micropillar optical resonators. Finally, in the last sections of this manuscript, we investigate the optomechanical properties of GaAs/AlAs micropillar cavities. We have performed numerical simulations through the finite element method that allowed us to explain the three-dimensional confinement mechanisms of optical and mechanical modes in these systems, and to calculate the main optomechanical parameters. This work shows that GaAs/AlAs micropillars present very interesting properties for future optomechanical experiments, such as very high mechanical resonance frequencies, large optical and mechanical quality factors at room temperature, and high values for the vacuum optomechanical coupling factors and for the Q • f products
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Wobkenberg, Paul Henrich. "Thin-film transistors for large area opto/electronics." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/4699.
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The present work addresses several issues in the field of organic and transparent electronics. One of them is the prevailing high power consumption in state-of-the-art organic field-effect transistors (OFETs). A possible solution could be the implementation of complementary, rather than unipolar logic, but this development is currently inhibited by a distinct lack of high performance electron transporting (n-channel) OFETs. Here, the issue is addressed by investigating a series of solution processable n-channel fullerene molecules in combination with optimized transistor architectures. Furthermore, the trend towards complementary circuit design could be facilitated by employing ambipolar organic semiconductors, such as squaraine molecules or polymer/fullerene blends. These materials can fill the role of p- or n-channel semiconductors and enable the facile implementation of power saving complementary-like logic, eliminating the cost-intensive patterned deposition of discrete p-and n-channel transistors. Alternatively, a patterning method for organic materials adapted from standard photolithography is discussed. Furthermore, ambipolar FETs are found to be capable of light sensing at wavelength of 400-1000 nm. Hence their use in low-cost, organic based optical sensor arrays can be envisioned. Another strategy to reduce the power consumption and operating voltages of OFETs is the use of ultra-thin, self-assembled molecular gate dielectrics, such as alkyl-phosphonic acid molecules. Based on this approach solution processed n- and p-channel OFETs and a complementary organic inverter circuit are demonstrated, which operate at less than 2 Volts. Finally, transparent oxide semiconductors are investigated for use in thin-film transistors. Titanium dioxide (TiO2) and zinc oxide (ZnO) films are deposited by means of a low-cost large area compatible spray pyrolysis technique. ZnO transistors exhibit high electron mobility of the order of 10 cm2/Vs and stable operation in air at less than 2 Volts. These results are considered significant steps towards the development of organic and transparent large-area optoelectronics.
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Björsell, Frida. "Teoribildning och bildtolkning som metod för nytänkande : en studie av heteronormativa diskurser med utgångspunkt i konstnären Chaterine Opies fotografi Self-Portrait/Cutting." Thesis, Konstfack, Institutionen för Bildpedagogik (BI), 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-506.
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Syftet med mitt examensarbete är att belysa resonemang rörande normalt respektive onormalt, maktstrukturer, genusfrågor och kommunikationsprocesser, med utgångspunkt i konstnären Catherine Opies fotografi Self-Portrait/Cutting från 1993. Verket rymmer en komplexitet eftersom brottet mot våra heteronormativa föreställningar utrycks så explicit. Det finns en ambivalens och direkthet i verket som fascinerar. De motstridiga läsningarna väcker ett behov av att förstå bilden på ett mer nyanserat sätt. Jag har medvetet valt att studera Self-Portrait utifrån teorier som ligger till grund för många konstnärer som väljer att röra sig i gränslandet för det samhället satt upp som norm. Teoribildningar som behandlar dikotomier som normalt och onormalt samt synen på den Andre, ligger även till grund för min gestaltning, där jag i praktiken undersökt hur man kan arbeta med gestaltning som metod för ett ifrågasättande av invanda föreställningar. Sammantaget har jag frågat mig på vilket sätt examensarbetets gestaltande del och tolkningsprocessen av Self-Portrait, kan bredda min förståelse av heteronormativa diskurser, samt på vilket sätt växelspelet mellan konstnärlig gestaltning, teoribildning och bildtolkning kan fungera som metod för ett ifrågasättande av normer och nytänkande inom bildpedagogiken. Min uppfattning är att slentrianmässiga värderingar oftast grundar sig i okunskap, men också genom medias påtvingade ideologier. Det är språket som möjliggör att vi kan reflektera över våra handlingar och därmed över oss själva. När vi omsätter våra tankar i språk – tal, skrift och gestaltande – omstruktureras och förändras tanken. Bildundervisningen öppnar för möjligheten att lyfta fram olika former av språksystem som inte strävar mot enhetliga svar. Insikten att det ofta finns flera ”sanningar” och att det är viktigt att ifrågasätta sitt eget och andras tänkande, kan i bästa fall motverka stereotypa föreställningar samt förtryck av individer. Jag menar att den kritiska kommunikationen, där eleverna själva skapar mening kring egna och andras bilder, kan uppmuntra eleverna till självständigt reflekterande. Att tolka verk utifrån disparata teorier, som jag valt att göra i mitt examensarbete, kan vara ett led i den riktningen. Genom att använda den egna kroppen som medium i min gestaltning har jag undersökt hur iscensättningen kan möjliggöra en djupare förståelse för hur vi antar och växlar mellan olika roller och identiteter. Gestaltningen har även medfört en bredare diskussion kring maktstrukturer och en insikt i att synen på den Andre ytterst handlar om synen på oss själva. Min tolkning av Self- Portrait/Cutting och mitt gestaltningsarbete har varit en inkörsport till ökad förståelse och i förlängningen verktyg för hur jag som bildpedagog kan arbeta växelvis med teoribildning och bildtolkning som metod för ifrågasättande och nytänkande.BI/Konst
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Perhirin, Steven. "Conception d'une extension opto-alimentée pour les observatoires de fond de mer : étude, développement et caractérisation d'interfaces opto-électroniques faible consommation." Thesis, Brest, 2013. http://www.theses.fr/2013BRES0063/document.
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Ce mémoire de thèse est consacré à la mise en place d'un système opto-électronique générique basé sur une liaison toute optique bidirectionnelle de 10km. L'architecture étudiée et développée est dédiée à l'extension d'un observatoire câblé de fond de mer afin d'atteindre de nouvelles zones d'exploration. Les travaux de recherche rapportés dans ce manuscrit présentent la réalisation d'un démonstrateur, qui permet la récupération de données, issues d'un instrument connecté à un module opto-alimenté, via une seule fibre optique où transitent simultanément deux voies de données en bande C et la puissance optique d'alimentation (à 1480nm) égale à 33dBm permettant de récupérer 180mW électrique sur le module opto-alimenté.Le contexte de cette thèse de doctorat est présenté au travers d'un état de l'art sur les moyens utilisés pour l'observation des océans et sur les systèmes électroniques à faible consommation. Après un rappel des caractéristiques essentielles de l'architecture de la liaison optique préalablement établie, nous nous concentrons sur la structure opto-électronique qui a pour but d’assurer la communication entre l’observatoire et l’instrument déporté de l’extension. La définition du cahier des charges a abouti au choix du capteur (hydrophone), du débit des données (5Mbit/s) et du protocole de communication (SPI 3-fils) utilisé entre les deux modules opto-électroniques, chacun à une extrémité de la fibre optique. L'effort a été porté sur la conception d'un module opto-alimenté faible consommation (66mW) où s'intègre l'instrument. Tout au long de ce document, les choix technologiques retenus lors de la conception des deux modules opto-électroniques sont argumentés. Le banc d'essai du démonstrateur a permis de valider la conception de cette extension et d'évaluer la qualité de la transmission des données (BER inférieur à 10-6). Le fonctionnement d'un premier prototype destiné à être marinisé a été présenté au travers de la détection et de la transmission de signaux acoustiques générés en bassin d'essai. De manière à rendre le système encore plus générique, une solution alternative à base d'un FPGA, permettant l'utilisation d'une interface SPI 4-fils sans modifier la liaison optique a été présentée et validéeThis PhD thesis is devoted to the design of an opto-electrical and generic system which uses a 10km long all-optical and bidirectional link. The studied and developed system is dedicated to extend a current cabled seafloor observatory, in order to reach new exploration areas. The research work described in this thesis presents the development and the realization of a demonstrator. This later collects data from an instrument connected to its optically powered unit. The optical power supply (33dBm at 1480nm), which provides up to 180mW electrical for the optically powered unit, and the optical data in C band, are transmitted simultaneously through the same single optical fiber.The thesis context is first presented through an overview of ocean observation systems and low consumption electronic devices. After a brief review on the main characteristics of the optical architecture, we focused on the opto-electrical structure which permits the communication between the observatory and the remote instrument. The desired requirements have led us to the choice of the sensor (hydrophone), the data bit rate (5Mbit/s) and the communication protocol (SPI 3-Wire) used between both opto-electrical units, each one located at the both ends of the optical link. A special attention was devoted to the conception of the optically powered which must be low power consumption (66mW). All along this document, technical choices involved in the realization of both opto-electrical units are presented. We could evaluate the performance of the data transmission (BER less than 10-6) by using a demonstrator's test bench. Then, a first prototype designed for the ocean environment was presented through experimental measurements. Those tests were conducted in a test pool and have consisted in the detection of acoustic signals. In order to increase the range of compatible instruments, an alternative solution based on a FPGA was described and approved. This new design allows the SPI 4-Wire to be employed without any change of the current optical architecture