998 resultados para Micro generation
Resumo:
A new practical method to generate a subspace of active coordinates for quantum dynamics calculations is presented. These reduced coordinates are obtained as the normal modes of an analytical quadratic representation of the energy difference between excited and ground states within the complete active space self-consistent field method. At the Franck-Condon point, the largest negative eigenvalues of this Hessian correspond to the photoactive modes: those that reduce the energy difference and lead to the conical intersection; eigenvalues close to 0 correspond to bath modes, while modes with large positive eigenvalues are photoinactive vibrations, which increase the energy difference. The efficacy of quantum dynamics run in the subspace of the photoactive modes is illustrated with the photochemistry of benzene, where theoretical simulations are designed to assist optimal control experiments
Resumo:
La miniaturització de la industria microelectrònica és un fet del tot inqüestionables i la tecnologia CMOS no n'és una excepció. En conseqüència la comunitat científica s'ha plantejat dos grans reptes: En primer lloc portar la tecnologia CMOS el més lluny possible ('Beyond CMOS') tot desenvolupant sistemes d'altes prestacions com microprocessadors, micro - nanosistemes o bé sistemes de píxels. I en segon lloc encetar una nova generació electrònica basada en tecnologies totalment diferents dins l'àmbit de les Nanotecnologies. Tots aquests avanços exigeixen una recerca i innovació constant en la resta d'àrees complementaries com són les d'encapsulat. L'encapsulat ha de satisfer bàsicament tres funcions: Interfície elèctrica del sistema amb l'exterior, Proporcionar un suport mecànic al sistema i Proporcionar un camí de dissipació de calor. Per tant, si tenim en compte que la majoria d'aquests dispositius d'altes prestacions demanden un alt nombre d'entrades i sortides, els mòduls multixip (MCMs) i la tecnologia flip chip es presenten com una solució molt interessant per aquests tipus de dispositiu. L'objectiu d'aquesta tesi és la de desenvolupar una tecnologia de mòduls multixip basada en interconnexions flip chip per a la integració de detectors de píxels híbrids, que inclou: 1) El desenvolupament d'una tecnologia de bumping basada en bumps de soldadura Sn/Ag eutèctics dipositats per electrodeposició amb un pitch de 50µm, i 2) El desenvolupament d'una tecnologia de vies d'or en silici que permet interconnectar i apilar xips verticalment (3D packaging) amb un pitch de 100µm. Finalment aquesta alta capacitat d'interconnexió dels encapsulats flip chip ha permès que sistemes de píxels tradicionalment monolítics puguin evolucionar cap a sistemes híbrids més compactes i complexes, i que en aquesta tesi s'ha vist reflectit transferint la tecnologia desenvolupada al camp de la física d'altes energies, en concret implantant el sistema de bump bonding d'un mamògraf digital. Addicionalment s'ha implantat també un dispositiu detector híbrid modular per a la reconstrucció d'imatges 3D en temps real, que ha donat lloc a una patent.
Resumo:
Le musée local, au Portugal, tel qu’il apparaît dans la perspective de la révolution socio-cultureile de 74, puis projeté à l’avant-scène de la muséologie portugaise renaissante, lors du IIe Atelier international de Nouvelle muséologie (Lisbonne/Seixal/Monte Redondo — Musées locaux/Nouvelle musólogie, novembre 85), se perpétue jusqu’à nos jours, tout au moins dans le discours de ses promoteurs, préoccupé par le rapport aux pouvoirs et aux populations. Fortement enraciné dans la structure municipale et associative, utilisé à ses débuts, à des degrés divers, comme un outil de militance communautaire, le musée local présente un modèle muséographique de type ethnographique diffusé à travers le pays. Celui-ci est fondé sur la participation de donateurs d’objets utiles de la vie courante, mis à contribution dans le programme, de même que sur l’apport des savoir-faire populaires et artisanaux, évitant de tomber dans le folklorisme par une réflexion alimentée par les universitaires. Ce mouvement naissant correspond à la mode de l’écomusée dont il épouse certains contours, tout en demeurant enraciné dans la tradition ethnographique du pays.
Resumo:
A análise histopatológica de tecido ósseo exige uma etapa de descalcificação. O método usual consiste na imersão das amostras em ácidos, mas para além de provocarem danos tecidulares, o processo é prolongado. A utilização de micro-ondas acelera a descalcificação, mas não deve comprometer a imagem microscópica. Objetivo: Diminuir a duração da descalcificação, mantendo a qualidade da imagem microscópica. Metodologia: Foram testadas amostras de osso compacto e esponjoso. Realizou-se a descalcificação pelo método convencional e pelo método em micro-ondas, através da adaptação de um protocolo conhecido. Utilizou-se ácido nítrico a 5% e 10%. Resultados: Nos fragmentos de maiores dimensões, após 4 horas com ácido nítrico a 10% em micro-ondas, não se conseguiu uma descalcificação completa, apesar da imagem histológica ser razoável. Nos fragmentos de osso esponjoso, verificou-se uma redução de cerca de 25 horas relativamente ao método convencional. Nas biópsias, houve uma redução de aproximadamente 10 horas, utilizando ácido nítrico a 5%. Com ácido nítrico a 10% houve destruição tecidular. Nos casos em que se obteve uma descalcificação completa, a imagem microscópica apresenta fraca qualidade. Conclusão: A utilização de micro-ondas com ácido nítrico a 5%/10%, aplicando o protocolo deste estudo, reduz a duração da descalcificação, mas compromete a imagem microscópica.
Resumo:
We examine the efficacy two volume spatial registration of pre and postoperative clinical computed tomography (CT) imaging to verify post-operative electrode array placement in cochlear implant (CI) patients. To measure the degree of accuracy with which the composite image predicts in-vivo placement of the array, we replicate the CI surgical process in cadaver heads. Pre-operative, post-operative, micro CT imaging and histology are utilized for verification.
Resumo:
El propósito principal de esta investigación, es conocer la situación actual de la industria turística en el Cantón Puerto Quito y realizar el diagnóstico del potencial agroturístico del recinto Tatalá; para ello es propicio realizar una conceptualización y diferenciación de los diferentes tipos de productos turísticos para evitar confusiones y rescatar el concepto que mejor se adapta a la realidad de este caso, el mismo que se detalla en el capítulo I. El método lógico utilizado es el Inductivo - descriptivo, con éste método se analizan casos particulares a partir de los cuales se extraen conclusiones de carácter general. En el capítulo II se realiza el diagnóstico del sector el que tiene por objeto conocer y describir la situación real de los finqueros y de Puerto Quito. Incluye además, la identificación de actores principales instituciones públicas y privadas, personas naturales que intervienen en el desarrollo de las actividades turísticas ( dueños de tierras, gobierno cantonal, asociaciones), usando las siguientes técnicas de investigación: entrevistas personales a empresarios turísticos del sector, grupos focales a funcionarios de la Alcaldía de Puerto Quito, revisión de información bibliográfica en la Alcaldía En el capítulo III se realiza el mapeo de recursos turísticos de la zona: clasificación de los entornos naturales de acuerdo a su potencialidad turística realizando visitas in situ al sector, entrevistas y encuestas a los habitantes del sector e investigación en entidades públicas y privadas. En el capítulo IV se diseña un cuadro de estrategias para potenciar el agroturismo en el recinto Tatalá y finalmente el capítulo V muestra las principales conclusiones y recomendaciones de la investigación.
Resumo:
El propósito de esta tesis es el dar a conocer un modelo de control
estratégico para pequeñas y microempresas de desarrollo de software en la
ciudad de Quito. Se ha escogido al software debido a que es uno de los sectores
con más potencial de crecimiento.
Para dar a conocer este modelo, se han investigado y analizado varias
teorías de control estratégico entre las cuales se da a conocer: las cinco P de
Henry Mintzberg, las estrategias genéricas del profesor Michael Porter, el Modelo
de las Siete <
Resumo:
We report on the results of a laboratory investigation using a rotating two-layer annulus experiment, which exhibits both large-scale vortical modes and short-scale divergent modes. A sophisticated visualization method allows us to observe the flow at very high spatial and temporal resolution. The balanced long-wavelength modes appear only when the Froude number is supercritical (i.e. $F\,{>}\,F_\mathrm{critical}\,{\equiv}\, \upi^2/2$), and are therefore consistent with generation by a baroclinic instability. The unbalanced short-wavelength modes appear locally in every single baroclinically unstable flow, providing perhaps the first direct experimental evidence that all evolving vortical flows will tend to emit freely propagating inertia–gravity waves. The short-wavelength modes also appear in certain baroclinically stable flows. We infer the generation mechanisms of the short-scale waves, both for the baro-clinically unstable case in which they co-exist with a large-scale wave, and for the baroclinically stable case in which they exist alone. The two possible mechanisms considered are spontaneous adjustment of the large-scale flow, and Kelvin–Helmholtz shear instability. Short modes in the baroclinically stable regime are generated only when the Richardson number is subcritical (i.e. $\hbox{\it Ri}\,{<}\,\hbox{\it Ri}_\mathrm{critical}\,{\equiv}\, 1$), and are therefore consistent with generation by a Kelvin–Helmholtz instability. We calculate five indicators of short-wave generation in the baroclinically unstable regime, using data from a quasi-geostrophic numerical model of the annulus. There is excellent agreement between the spatial locations of short-wave emission observed in the laboratory, and regions in which the model Lighthill/Ford inertia–gravity wave source term is large. We infer that the short waves in the baroclinically unstable fluid are freely propagating inertia–gravity waves generated by spontaneous adjustment of the large-scale flow.
Resumo:
Inertia-gravity waves exist ubiquitously throughout the stratified parts of the atmosphere and ocean. They are generated by local velocity shears, interactions with topography, and as geostrophic (or spontaneous) adjustment radiation. Relatively little is known about the details of their interaction with the large-scale flow, however. We report on a joint model/laboratory study of a flow in which inertia-gravity waves are generated as spontaneous adjustment radiation by an evolving large-scale mode. We show that their subsequent impact upon the large-scale dynamics is generally small. However, near a potential transition from one large-scale mode to another, in a flow which is simultaneously baroclinically-unstable to more than one mode, the inertia-gravity waves may strongly influence the selection of the mode which actually occurs.
Resumo:
Although climate models have been improving in accuracy and efficiency over the past few decades, it now seems that these incremental improvements may be slowing. As tera/petascale computing becomes massively parallel, our legacy codes are less suitable, and even with the increased resolution that we are now beginning to use, these models cannot represent the multiscale nature of the climate system. This paper argues that it may be time to reconsider the use of adaptive mesh refinement for weather and climate forecasting in order to achieve good scaling and representation of the wide range of spatial scales in the atmosphere and ocean. Furthermore, the challenge of introducing living organisms and human responses into climate system models is only just beginning to be tackled. We do not yet have a clear framework in which to approach the problem, but it is likely to cover such a huge number of different scales and processes that radically different methods may have to be considered. The challenges of multiscale modelling and petascale computing provide an opportunity to consider a fresh approach to numerical modelling of the climate (or Earth) system, which takes advantage of the computational fluid dynamics developments in other fields and brings new perspectives on how to incorporate Earth system processes. This paper reviews some of the current issues in climate (and, by implication, Earth) system modelling, and asks the question whether a new generation of models is needed to tackle these problems.