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Lemos, Leticia Lindenberg. "Do controle de impacto à promoção do fluxo: um debate sobre polos geradores de tráfego em São Paulo." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/16/16139/tde-01062017-162523/.
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No Brasil e em São Paulo as políticas públicas de mobilidade urbana foram historicamente orientadas para promover a fluidez dos automóveis. A partir do século XXI, particularmente na segunda década, o debate sobre mobilidade se desloca, passando a focar nas pessoas, ao invés de veículos, e na promoção de modos ativos. Esta pesquisa se insere neste contexto, analisando o instrumento de controle de impacto no sistema de circulação urbana denominado Polos Geradores de Tráfego. A partir de novos conceitos referenciais para mobilidade urbana, discutimos a evolução do marco regulatório referencial para este instrumento. Analisamos, então, como ele tem sido aplicado pela Companhia de Engenharia de Tráfego através de uma ampla amostra desses empreendimentos e do estudo de caso comparativo entre dois shopping centers em São Paulo. Os resultados indicam que o instrumento tratado aqui e sua aplicação apresentam baixa aderência às condições territoriais, levando a uma abordagem limitada dos elementos de produção e atração de viagens. Com esta pesquisa, esperamos contribuir para o debate atual sobre a produção de cidades mais sustentáveis e mais acessíveis espacial e socialmente.In Brazil and in São Paulo, the public policies concerning urban mobility have been historically oriented to promote the traffic flow for automobile. On the beginning of the XXI century, and particularly on its second decade, the debate about mobility started to a focus on people, rather than vehicles, and on the promotion of active modes. In this context, this research analysis the instrument used to control the impact on the circulation system, entitled Traffic Generating Poles. Based on new references for mobility policies we discuss the evolution of the regulatory framework for this instrument. We analyze how it has been implemented by the Traffic Engineering Company through a large sample of these buildings and a case study comparing two shopping centers in São Paulo. The results indicate that the instrument and its implementation present a low adherence to the conditions of the territory, leading to a limited approach on the elements of production and attraction of trips. With this research, we hope to contribute to the current debate on the production of cities that are more accessible both spatially and socially, and more environmentally friendly.
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Vinson, Jean-Philippe. "Pôles générateurs de flux de déplacements non pendulaires dans une agglomération multipolarisée : contribution à une nouvelle approche des transports publics à travers le cas de la Métropole d’Aix-Marseille Provence." Electronic Thesis or Diss., Université Gustave Eiffel, 2025. https://these.univ-paris-est.fr/intranet/2025/UEFL-2025/TH2025UEFL2010.pdf.
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De nos jours, les déplacements dans une agglomération sont souvent abordés selon les phénomènes de pointe avec des heures éponymes calquées sur les déplacements pendulaires (MUNCH, 2017). Or, sur certains territoires, les « autres motifs » deviennent prépondérants. C’est le cas des Bouches-du-Rhône, dont la Métropole d'Aix-Marseille Provence s’y confond quasi-intégralement (EMD BDR 2009). Cette dernière intéresse de par sa taille (1,9 millions d’habitants), sa jeunesse institutionnelle (créée le 1er janvier 2016) et son caractère multipolaire unique englobant le grand périurbain. Le but de ce travail croisant aménagement, mobilité, ingénierie et sociologie a été d’évaluer puis optimiser la gestion des flux de déplacements non pendulaires (DNP) engendrés par les pôles générateurs métropolitains afférents, en vue de l'adaptation des réseaux de transport public soumis à des objectifs de report modal.Nous avons tâché d’y répondre en deux parties. Il y a d’abord une première partie de cadrage avec la définition des pôle générateurs de déplacements non-pendulaires (PG DNP) puis du contexte géographique et institutionnel de notre terrain d’études en montrant son caractère hétérogène et encore mouvant avant de s’intéresser aux enquêtes de déplacements et leur conception vis-à-vis des DNP, offrant une connaissance macroscopique des déplacements locaux. Puis, la deuxième partie voit la création d’un protocole d’étude des DNP à travers l’idée que les PG DNP exercent une pression résultante de la fréquentation d’usage ainsi que de son environnement dont une meilleure connaissance peut permettre une réduction de cette pression d’usage. Une approche catégorielle des DNP a ainsi été appliqué et a abouti à cinq types de PG DNP que nous avons tâché de caractériser plus finement à travers l’étude de nouvelles données (billettique, circulation et GPS), ce qui a eu pour résultat de révéler les différents rythmes de fonctionnement des catégories de PG DNP. Enfin le dernier chapitre traitant des flux de DNP à l’aune des visions opérationnelles et citoyennes a révélé les difficultés d’adaptation aux DNP d’un outil de simulation tel que Metropolis 13+ si ces flux ne sont pas pensés nativement, ainsi que la prise en compte des DNP de manière indifférenciée vis-à-vis des autres types de déplacement, dans un contexte d’offre locale de transports en commun encore considéré insuffisanteNowadays, commuting in an urban area is often addressed according to peak phenomena with eponymous hours modelled on commuting (MUNCH, 2017). In some jurisdictions, the “other grounds” become predominant. This is the case of the Bouches-du-Rhône, where the Aix-Marseille Provence Metropolis is almost entirely merged (EMD BDR 2009). The latter is interesting because of its size (1.9 million inhabitants), its institutional youth (created on January 1, 2016) and its unique multipolar character encompassing the large peri-urban. The aim of this work, which combines planning, mobility, engineering and sociology, was to evaluate and then optimize the management of non-commuting travel flows (NCT) generated by the related metropolitan generating poles, for the adaptation of public transport networks subject to modal shift objectives. We tried to answer it in two parts. There is first a first part of framing with the definition of non-commuting movement generating poles (NCT GP) the geographical and institutional context of our field of study by showing its heterogeneous character and still moving before being interested in travel surveys and their conception vis-à-vis the NCT, offering a macroscopic knowledge of local travel. The second part sees the creation of a protocol for studying NCT through the idea that GP NCT exert a pressure resulting from the use of frequentation and its environment, which a better knowledge can allow a reduction in this pressure. A categorical approach of the NCT was applied and resulted in five types of GP NCT that we tried to characterize more finely through the study of new data (ticketing, traffic and GPS), which resulted in revealing the different operating rhythms of GP NCT grades. Finally, the last chapter dealing with NCT flows in terms of operational and citizen visions revealed the difficulties of adapting to the NCT a simulation tool such as Metropolis 13+ if these flows are not thought natively, as well as the consideration of the NCT in an undifferentiated way vis-à-vis other types of travel, in a context of local public transport offer still considered insufficient
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Zebrowska, Anna. "Integration or assimilation : a study of second generation Poles in England." Thesis, University of Surrey, 1986. http://epubs.surrey.ac.uk/594/.
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Checksfield, M. J. "Pole slipping protection for small and medium sized embedded generation." Thesis, University of Bath, 1997. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760705.
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Fragemann, Anna. "Optical parametric amplification with periodically poled KTiOPO4." Doctoral thesis, KTH, Laserfysik, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-531.
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This thesis explores the use of engineered nonlinear crystals from the KTiOPO4 (KTP) family as the gain material in optical parametric amplifiers (OPAs), with the aim to achieve more knowledge about the benefits and limitations of these devices. The work aims further at extending the possible applications of OPAs by constructing and investigating several efficient and well performing amplifiers. An OPA consists of a strong pump source, which transfers its energy to a weak seed beam while propagating through a nonlinear crystal. The crystals employed in this work are members of the KTP family, which are attractive due to their large nonlinear coefficients, high resistance to damage and wide transparency range. The flexibility of OPAs with respect to different wavelength regions and pulse regimes was examined by employing various dissimilar seed and pump sources. The possibility to adapt an OPA to a specific pump and seed wavelength and achieve efficient energy conversion between the beams, originates from quasi-phasematching, which is achieved in periodically poled (PP) nonlinear crystals. Quasi-phasematched samples can be obtained by changing the position of certain atoms in a ferroelectric crystal and thereby reversing the spontaneous polarisation. In this thesis several material properties of PP crystals from the KTP family were examined. The wavelength and temperature dispersion of the refractive index were determined for PP RbTiOPO4, which is essential for future use of this material. Another experiment helped to increase the insight into the volumes close to domain walls in PP crystals Further, several OPAs were built and their ability to efficiently amplify the seed beam without changing its spectral or spatial properties was studied. Small signal gains of up to 55 dB and conversion efficiencies of more than 35 % were achieved for single pass arrangements employing 8 mm long PPKTP crystals. Apart from constructing three setups, which generated powerful nanosecond, picosecond and femtosecond pulses, the possibility to amplify broadband signals was investigated. An increase of the OPA bandwidth by a factor of approximately three was achieved in a noncollinear configuration.QC 20101013
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Levenius, Martin. "Optical Parametric Devices in Periodically Poled LiTaO3." Doctoral thesis, KTH, Kvantelektronik och -optik, QEO, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-134915.
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Optical parametric frequency conversion based on quasi phase matching (QPM) in nonlinear optical crystals is a powerful technique for generating coherent radiation in wavelength ranges spanning from the mid-infrared (mid-IR) to the blue, displaying low thermal load and high efficiency.This thesis shows how QPM in one- (1D) or two-dimensional (2D) lattices can be employed to engineer novel devices for parametric downconversion in the IR, af-fording freedom in designing both spectral and angular properties of the parametric output. Experimental demonstrations of parametric devices are supported by theoreti-cal modelling of the nonlinear conversion processes.In particular, broadband parametric downconversion has been investigated in 1D QPM lattices, through degenerate downconversion close to the point of zero group-velocity dispersion. Ultra-broadband optical parametric generation (OPG) of 185 THz bandwidth (at 10 dB), spanning more than one octave from 1.1 to 3.7 μm, has been achieved in periodically poled 1 mol% MgO-doped near-stoichiometric LiTaO3 (MgSLT) of 25 μm QPM period, pumped at 860 nm. Such broadband gain is of high interest for ultrashort optical pulse amplification, with applications in high harmonic generation, ultrafast spectroscopy and laser ablation. Furthermore, the det-rimental impact of parasitic upconversion, creating dips in the OPG spectrum, has been investigated. By altering the pump pulse duration, energy can be backconverted to create peaks at the involved OPG wavelengths, offering a possible tool to enhance broadband parametric gain spectra.The engineering of the angular properties of a parametric output benefits greatly from 2D QPM, which is investigated in this thesis by the specific example of hexagonally poled MgSLT. It is demonstrated how two OPG processes, supported by a single 2D QPM device, can exhibit angularly and spectrally degenerate signals (idlers). This degeneracy results in a coherent coupling between the two OPG pro-cesses and a spectrally degenerate twin-beam output in the mid-IR (near IR). 2D QPM devices exhibiting such coherently coupled downconversion processes can find applications as compact sources of entangled photon-pairs. This thesis further illus-trates the design freedom of 2D QPM through the demonstration of a device support-ing multiple parametric processes, thus generating multiple beams from the mid-IR to the blue spectral regions.QC 20131204
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Fragemann, Anna. "Optical parametric amplification with periodically poled KTiOPO4." Doctoral thesis, KTH, Physics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-531.
Full textAbstract:
This thesis explores the use of engineered nonlinear crystals from the KTiOPO4 (KTP) family as the gain material in optical parametric amplifiers (OPAs), with the aim to achieve more knowledge about the benefits and limitations of these devices. The work aims further at extending the possible applications of OPAs by constructing and investigating several efficient and well performing amplifiers.
An OPA consists of a strong pump source, which transfers its energy to a weak seed beam while propagating through a nonlinear crystal. The crystals employed in this work are members of the KTP family, which are attractive due to their large nonlinear coefficients, high resistance to damage and wide transparency range. The flexibility of OPAs with respect to different wavelength regions and pulse regimes was examined by employing various dissimilar seed and pump sources.
The possibility to adapt an OPA to a specific pump and seed wavelength and achieve efficient energy conversion between the beams, originates from quasi-phasematching, which is achieved in periodically poled (PP) nonlinear crystals. Quasi-phasematched samples can be obtained by changing the position of certain atoms in a ferroelectric crystal and thereby reversing the spontaneous polarisation.
In this thesis several material properties of PP crystals from the KTP family were examined. The wavelength and temperature dispersion of the refractive index were determined for PP RbTiOPO4, which is essential for future use of this material. Another experiment helped to increase the insight into the volumes close to domain walls in PP crystals
Further, several OPAs were built and their ability to efficiently amplify the seed beam without changing its spectral or spatial properties was studied. Small signal gains of up to 55 dB and conversion efficiencies of more than 35 % were achieved for single pass arrangements employing 8 mm long PPKTP crystals. Apart from constructing three setups, which generated powerful nanosecond, picosecond and femtosecond pulses, the possibility to amplify broadband signals was investigated. An increase of the OPA bandwidth by a factor of approximately three was achieved in a noncollinear configuration.
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Garcia, Patrícia Baldini de Medeiros. "Acessibilidade a hospitais." Universidade Federal de São Carlos, 2012. https://repositorio.ufscar.br/handle/ufscar/4364.
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Developments in the health sector, especially those placed in public care are fundamental to the care of the entire population of a city and region. The location of health projects such as "Santa Casa" was made since many decades ago, or even the latest developments seem not to have been concerned with the accessibility of the population. Moreover, the travels generators poles, including the establishments of the health sector, cause significant impacts on its surroundings and also in the transport systems of the region they live. In general, the public hospitals, mainly in Brazil, aim to attend the portions of the population of low income families that use displacement on foot, by car or public transport. As a result, this study aimed to perform an analysis of levels of accessibility to hospitals such as "Santa Casa", considering mainly the population groups that most need the public health. The proposed method is based on an indicator (time) to measure accessibility to hospitals by different ways: on foot, by car and public transport, making use of geographic information systems. IBGE data were used to estimate the income levels of traffic areas. A survey with users from hospitals located in the cities of Rio Claro and São Carlos was performed to characterize the source and location of the travel. Using the data obtained in both case studies it was found that the population, in most cases, has used the car travel to hospitals. The accessibility by car was high, because even in distant neighborhoods, the travel time was at 15 minutes for both cities. In contrast, traveling on foot had low accessibility in relation to hospitals, mainly in the distant neighborhoods. The analysis done for public transport accessibility shows the minimum value of 30 minutes to Rio Claro and 35 minutes to São Carlos. Analyzing data from the 2000 Census, it is evident that the population with lower monthly household income is concentrated in the suburb areas of the cities. Thus, the distances done every day by the citizens compromise the access to different services available in the cities, as the travel time, or the lack of public transport routes, or lack of conditions of using public transport.
Empreendimentos do setor de saúde, principalmente os inseridos na rede pública de atendimento, são fundamentais para o atendimento de toda a população de uma cidade e região. A localização dos empreendimentos de saúde do tipo Santa Casa , em geral, foi feita há muitas décadas, ou mesmo os empreendimentos mais recentes, parecem não ter tido a preocupação com a acessibilidade da população. Além disso, os polos geradores de viagens, dentre eles os estabelecimentos do setor de saúde, causam impactos significativos nos seus arredores e também nos sistemas de transporte da região em que estão inseridos. Os hospitais públicos, principalmente no Brasil, visam atender às parcelas da população de menor renda, que se utilizam de deslocamentos a pé, por automóvel ou por transporte coletivo público por ônibus. Em vista disso, este trabalho teve como objetivo realizar uma análise dos níveis de acessibilidade a hospitais do tipo Santa Casa , considerando, principalmente, as parcelas da população que mais necessitam do sistema público de saúde. O método proposto se baseou em um indicador (tempo) para se medir a acessibilidade aos hospitais pelos modos a pé, automóvel e transporte coletivo, fazendo-se uso de sistemas de informações geográficas. Dados do IBGE foram utilizados para a estimativa de níveis de rendimento de zonas de tráfego. Uma pesquisa com usuários dos hospitais localizados nas cidades de Rio Claro e São Carlos foi realizada para a caracterização e localização de origem das viagens. Através dos dados obtidos nestes os estudos de caso, verificou-se que a população, na maioria das vezes, utiliza o automóvel para realizar as viagens aos hospitais. A acessibilidade por automóvel obteve tempo de viagem de até 15 minutos, mesmo em bairros mais distantes, para as duas cidades. Em contrapartida, para as viagens a pé, o tempo de viagem médio foi de até 20 minutos em um raio de 1,5 km dos hospitais, para os estudos de caso. A análise feita para o transporte coletivo mostra o valor de tempo mínimo de 30 minutos para Rio Claro e de 35 minutos para São Carlos. Analisando-se os dados do Censo 2000, fica evidente que a população com menor rendimento médio mensal familiar se concentra nas regiões periféricas das cidades. Assim, as distâncias a serem vencidas diariamente pelos cidadãos comprometem o acesso aos diversos serviços disponíveis nas cidades, seja pelo tempo de viagem, ou pela falta de linhas de transporte público, ou de condições de se utilizar o transporte público.
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Voratovic, Dayen Chad. "Generation and Detection of Coherent Pulse Trains in Periodically Poled Lithium Niobate Through Optical Parametric Amplification." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1324406162.
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Khademian, Ali. "Highly Efficient Single Frequency Blue Laser Generation by Second Harmonic Generation of Infrared Lasers Using Quasi Phase Matching in Periodically Poled Ferroelectric Crystals." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc799538/.
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Performance and reliability of solid state laser diodes in the IR region exceeds those in the visible and UV part of the light spectrum. Single frequency visible and UV laser diodes with higher than 500 mW power are not available commercially. However we successfully stabilized a multi-longitudinal mode IR laser to 860 mW single frequency. This means high efficiency harmonic generation using this laser can produce visible and UV laser light not available otherwise. In this study we examined three major leading nonlinear crystals: PPMgO:SLN, PPKTP and PPMgO:SLT to generate blue light by second harmonic generation. We achieved record high net conversion efficiencies 81.3% using PPMgO:SLT (~500 mW out), and 81.1% using PPKTP (~700 mW out). In both these cases an external resonance buildup cavity was used. We also studied a less complicated single pass waveguide configuration (guided waist size of ~ 5 um compared to ~60 um) to generate blue. With PPMgO:SLN we obtained net 40.4% and using PPKT net 6.8% (110mW and 10.1 mW respectively).
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Hellström, Jonas. "Nanosecond optical parametric oscillators and amplifiers based on periodically poled KTiOPO4." Doctoral thesis, KTH, Physics, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3269.
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Optical parametric oscillators (OPOs) and optical parametricamplifiers (OPAs) constitute a class of optical frequencyconverting devices that have many possible applications, e.g.in range finding, molecular spectroscopy and medicine. They canconvert the frequency of the incident pump field with highefficiency, and generate two waves at new frequencies that willbe continuously tuneable over a wide spectral range. Virtuallyany wavelengths within the transparency region of the nonlinearmaterial can be generated if the material can bequasi-phasematched (QPM). In addition, QPM gives thepossibility to utilise the largest nonlinear tensor element ofthe material and allows walk-off free interaction between thewaves.
The aims of this thesis have been to investigate thepossibility to use QPM KTiOPO4crystals as nonlinear material in nanosecond OPOsand OPAs operating at room-temperature, and to explore theadvantages and shortcomings of these devices. The technique ofelectric field poling has been employed to implement the QPMstructure in flux grown KTiOPO4(KTP).
The main conclusion is that periodically poled KTP (PPKTP)is a suitable material to use in nanosecond OPOs and OPAs. Thematerial properties that foremost make KTP into an attractivenonlinear material are: The large value of the nonlinearcoefficient d33, the high resistance to optically inducedbreakdown, the low susceptibility to grey-track formation, theinsensitivity to the photorefractive effect, the widetransparency and the low coercive field.
The thesis shows that it is possible to pole large volumesof KTP with a high quality of the QPM structure. Highlyefficient nanosecond OPOs have been constructed during thisproject. Maximum conversion efficiencies have reached 45 % inthe case of a singly resonant OPO (SRO) built around a 3 mmthick PPKTP crystal. Total pulse energies for both the signal(1.72 µm) and the idler (2.8 µm) of up to 18 mJ wasreached and an average output power of 2 W was obtained forthis sample. However, up to 24 W was produced in a doublyresonant OPO operating close to degeneracy. The efficiencyreached 48 % for that case. Truly continuous and very widespectral tuning has also been demonstrated, as well as a narrowbandwidth OPO operating on one single longitudinal mode.
Keywords:optical parametric oscillators, opticalparametric amplifiers, quasi-phasematching, KTiOPO4, nonlinear optics, frequency conversion, periodicelectric field poling, ferroelectrics, high-order secondharmonic generation, electro-optic effect.
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Staniewicz, Teresa Agnes. "Ethnicity maintenance : its contingent nature and impact on health : case studies of second generation Poles in the West Midlands (UK) and South Michigan (US)." Thesis, University of Warwick, 2001. http://wrap.warwick.ac.uk/4179/.
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OBJECTIVES My topic of research is a comparative study of ethnicity and (selected) health patterns among second generation Poles (and to a lesser extent, first generation Poles), looked at by means of two case studies, one in the UK and one in the USA. I examine the level of ethnicity (cultural) maintenance in a white - assumed assimilated - minority ethnic group in two specific geographic locations and therefore the context specific nature of ethnicity maintenance. I also examine whether it is possible to assess the impact of such maintenance on their personal health, well-being, and quality of life. METHODS My research design includes a (smaller, post WWII) selection of first generation UK and USA Polish respondents who act as point of reference, and allow me to define within this study, the parameters of the cultural 'nuances' in question. My design allows for the assessment of any evidence of ethnic self-identity and a common sub-cultural identity, as well as any differences between the two groups of respondents in relation to their respective degrees of co-operation, and accommodation problems, with host groups. The collection of data is operationalized via multiple methods, including questionnaires. I employ the use of qualitative, quantitative, and ethnographic elements, thus allowing for multidimensional analysis of selected issues. Comparisons are made with extant data from both the host ( indigenous) communities. RESULTS/CONCLUSION Empirical results bore out variations in the degree of maintained ethnic lifestyles, across a range of social groups. Some of the differences can be explained by the different environments (UK and USA), as well as the diasporic nature of the first generation's immigration experiences. Qualitative and ethnographic evidence was found to be crucial in explaining the various affective ethnic nuances that quantitative methods are unable to reveal, such as the pervasive impact that the first generation's diasporic experiences, as well as the nature of the Polish exiled community, have had on the second generation, both in the UK and the USA, and their respective qualities of life. This study has indicated that maintaining one's ethnic roots can for these individuals be just as problematic, although in differing ways, as for members of non-white ethnic minorities.
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Pieleszová, Katarzyna. "Centrum Ponava Brno, Královo Pole." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2014. http://www.nusl.cz/ntk/nusl-227110.
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The submission of this thesis was preceded by a specialised studio „Brněnské nábřeží a kulturní čtvrť Ponava“. This work focused on a complex urban architectural solution to the area around the former “Jaselská kasárna”, the urban context, transport services, the field configuration etc. The thesis follows this project in a section defined by streets U Červeného mlýna, Staňkova and Střední. The goal of the thesis lies in the creation of an intensive goal – a cultural area, which will offer a high-quality space for intergenerational communication and new social experiences and activities. It newly connects the urban part Ponava with the town center of Brno by a high-quality axis for pedestrian and cycling transport. The project of this cultural area arose after a thorough analysis of surrounding, intercity and global relations as a combination of aims: for children – the elementary art school with graphic and dancing fields, for seniors – leisure time center, and for all together - a multifunctional concert hall and a revitalized area of the former industrial zone of furniture production to a multipurpose intergenerational area with a modern art gallery, offices for young businessmen, architects and artists, and a music club in the basement of the gallery.
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Mason, Elliott J. (Elliot James) 1972. "Applications of optical parametric downconversion : I. Self-phase locking, [and] II. Generation of entangled photon pairs in periodically-poled lithium niobate." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/29233.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.Includes bibliographical references (p. 108-114).
Nonlinear optics plays a key role in many applications not only as a means of frequency synthesis and control, but also as a source of twin photons and other nonclassical states of light. Advances in nonlinear materials, including engineered nonlinear interactions through the use of quasi-phase matching, have increased the flexibility and performance of many nonlinear optical devices. One of the devices presented in this thesis is a 2:1 frequency divider based on self-phase locking in a type-II phase matched optical parametric oscillator. This device is investigated both theoretically and experimentally. Results are also presented on fabrication of periodically-poled nonlinear crystals for quasi-phase matching in lithium niobate and barium magnesium fluoride. Finally, a high-efficiency frequency-nondegenerate twin photon source is implemented in periodically-poled lithium niobate.
by Elliott J. Mason, III.
Ph.D.
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Qvarngård, Daniel. "Modeling Optical Parametric Generation in Inhomogeneous Media." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74256.
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Wang, Shunhua. "Fabrication and characterization of periodically poled KTB and RB-doped KTB for applications in the visible and UV." Doctoral thesis, KTH, Physics, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-483.
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This thesis deals with the fabrication and the characterization of periodically-poled crystals for use in lasers to generate visible and UV radiation by second-harmonic generation (SHG) through quasi-phasematching (QPM). Such lasers are of practical importance in many applications like high-density optical storage, biomedical instrumentation, colour printing, and for laser displays.
The main goals of this work were: (1) to develop effective monitoring methods for poling of crystals from the KTiOPO4 (KTP) family, (2) to develop useful non-destructive domain characterization techniques, (3) to try to find alternative crystals to KTP for easier, periodic poling, (4) to investigate the physical mechanisms responsible for optical damage in KTP. The work shows that the in-situ SHG technique used together with electro-optic monitoring, makes it possible to obtain reliable, real-time information regarding the poling quality over the whole crystal aperture during the electric-field poling process. Using this combined monitoring method, both KTP and Rb-doped KTP (RKTP) crystals were successfully poled. By comparing these two crystals, we found that a low-doped KTP has a substantially reduced ionic conductivity and, thus, a high-quality periodic poling can be obtained without otherwise affecting the properties of the crystal. RKTP is a good alternative candidate to KTP for poling purpose. We have also shown that Atomic Force Microscopy (AFM) is an informative tool for investigating domain nucleation, growth, and merging. Furthermore, we have demonstrated a simple technique for 3D characterization of QPM samples. It utilizes a group-velocity mismatched, type-II SHG of femtosecond pulses for layer-by-layer monitoring of the effective nonlinearity along the propagation direction of the beam. The quality of these crystals was finally reflected in a number of SHG experiments with a variety of laser sources. High energies and high efficiencies were thus demonstrated using CW, mode-locked and Q-switched lasers. Gratings with pitches smaller than 3 µm, were demonstrated for first-order UV generation. Type-II QPM SHG was demonstrated as a technique for reducing the fabrication constraints.
High intensity light in the visible and the UV leads to modification of the material properties and, eventually, to optical damage. In KTP and its isomorphs, the first sign of material change is an optically-induced absorption. We have used thermal-lens spectroscopy with a common-path interferometer for high-sensitivity measurements of green light-induced infrared absorption dynamics in single-domain and periodically-poled KTP (PPKTP). The saturated, green light-induced absorption has been shown to be consistently higher in periodically-poled crystals, and is attributed to the creation of stoichiometric and interstitial defects in the crystals during the poling process. Finally, irreversible bulk damage thresholds in PPKTP have been determined for pulsed frequency converters. As the characteristics of optical damage are closely related to the material quality, this investigation can provide useful information for crystal manufactures and will help to optimise the crystal growth conditions.
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Machado, Cláudia Aparecida Soares. "Técnicas de sensoriamento remoto para identificação de áreas de concentração de polos geradores de viagens." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3138/tde-14052014-152928/.
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O objetivo desta Tese é a proposição de uma metodologia alternativa para planejamento de transportes que contempla as ferramentas disponíveis na ciência do sensoriamento remoto. A perspectiva adotada analisa aspectos do planejamento de transportes urbanos, tendo como embasamento os dados e informações advindos das imagens de satélite com alto poder de resolução espacial. A metodologia usa a abordagem baseada em objetos para classificar imagens de satélite de sensoriamento remoto. Através do processo de classificação, identificam-se feições urbanas úteis para o planejamento de transporte, em especial áreas de concentração de polos geradores de viagens do município de João Pessoa no estado da Paraíba, Brasil. A proposta é que com base nesses dados, e outros provenientes de uma pesquisa de campo (pesquisa domiciliar origem/destino), é possível caracterizar o uso do solo e a correspondente demanda por transportes. O estudo se justifica por propor uma alternativa mais ágil e menos onerosa, em comparação aos métodos tradicionais de construção e atualização da base de dados para análises de transportes. Ao identificar as regiões da cidade com as maiores quantidades de viagens geradas, os resultados obtidos auxiliam nas ações de planejamento do sistema de transportes, visando alcançar o equilíbrio entre oferta e demanda de transporte com o uso do solo urbano.The objective of this Thesis is to propose an alternative method of transportation planning that considers the tools available in the science of remote sensing. The perspective adopted examines aspects of urban transportation planning, having as basis the data and information coming from satellite images with high spatial resolution. The methodology uses the object-based approach to classify remote sensing satellite imagery. Through the classification process, urban features useful for transportation planning are identified, mainly areas of concentration of trip generation in the city of João Pessoa, state of Paraíba, Brazil. The proposal is that, based on these data, and others from a field research (origin/destination home-interview survey), it is possible to characterize the land use and the corresponding demand for transport. The study is justified because it proposes a more agile and less costly alternative, compared to traditional methods of building and updating the database for transport analysis. By identifying areas of the city with the largest amounts of trips generated, the results support planning actions on the transportation system, in order to achieve a balance between transport supply and demand with urban land use.
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Guesdon, Romain. "Estimation de poses humaines par apprentissage profond : application aux passagers des véhicules autonomes." Electronic Thesis or Diss., Lyon 2, 2024. http://www.theses.fr/2024LYO20002.
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La recherche concernant les voitures autonomes a fortement progressé ces dernières décennies, en se concentrant particulièrement sur l'analyse de l'environnement extérieur et sur les tâches liées à la conduite. Cela a permis une importante croissance de l'autonomie des véhicules particuliers. Dans ce nouveau contexte, il peut être pertinent de s'intéresser aux passagers de ces véhicules autonomes afin d'étudier le comportement de ces derniers face à cette révolution du moyen de transport. C'est pour approfondir ces thématiques que le projet région AURA AutoBehave a été mis en place. Ce projet réunit plusieurs laboratoires menant des recherches dans différentes disciplines scientifiques liées à cette thématique telles que la vision par ordinateur, la biomécanique, les émotions ou encore l'économie des transports. Cette thèse menée au laboratoire LIRIS s'inscrit donc dans ce projet, dans laquelle nous nous intéressons aux méthodes d'estimation de poses humaines des passagers par apprentissage profond. Nous avons d'abord étudié les solutions de l'état de l'art, et avons développé un jeu de données ainsi qu'une métrique plus adaptée aux contraintes de notre contexte. Nous nous sommes également intéressés à la visibilité des points afin d'aider l'estimation de la pose. Par la suite, nous nous sommes attaqués à la problématique de généralisation de domaine pour l'estimation de poses dans le but de proposer une solution efficace dans des conditions inconnues. Ainsi, nous nous sommes intéressés à la génération de données synthétiques de passagers pour l'estimation de poses afin de combler le manque de jeux de données annotés disponibles dans notre contexte. Nous avons étudié l'application de réseaux génératifs ainsi que de méthodes modélisation 3D à notre problématique. Nous nous sommes appuyés sur ces données pour proposer différentes stratégies d'entraînement et deux nouvelles architectures. L'approche par fusion proposée associée aux stratégies d'entraînement permet de tirer profit de jeux de données génériques et de jeux de données spécifiques, afin d'améliorer les capacités de généralisation des méthodes d'estimation de poses à l'intérieur d'une voiture, en particulier sur le bas du corpsResearch into autonomous cars has made great strides in recent decades, focusing particularly on analysis of the external environment and driving-related tasks. This has led to a significant increase in the autonomy of private vehicles. In this new context, it may be relevant to take an interest in the passengers of these autonomous vehicles, to study their behavior in the face of this revolution in the means of transport. The AURA AutoBehave project has been set up to explore these issues in greater depth. This project brings together several laboratories conducting research in different scientific disciplines linked to this theme, such as computer vision, biomechanics, emotions, and transport economics. This thesis carried out at the LIRIS laboratory is part of this project, in which we focus on methods for estimating the human poses of passengers using deep learning. We first looked at state-of-the-art solutions and developed both a dataset and a metric better suited to the constraints of our context. We also studied the visibility of the keypoints to help estimate the pose. We then tackled the problem of domain generalisation for pose estimation to propose an efficient solution under unknown conditions. Thus, we focused on the generation of synthetic passenger data for pose estimation. Among other things, we studied the application of generative networks and 3D modeling methods to our problem. We have used this data to propose different training strategies and two new network architectures. The proposed fusion approach associated with the training strategies makes it possible to take advantage of both generic and specific datasets, to improve the generalisation capabilities of pose estimation methods inside a car, particularly on the lower body
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Song, Peter. "Millimeter-wave integrated circuit design in silicon-germanium technology for next generation radars." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53450.
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In this thesis, the circuits which comprise the front-end of a millimeter-wave transmit-receive module are investigated using a state-of-the-art 90 nm SiGe BiCMOS process for use in radar remote sensing applications. In Chapter I, the motivation for a millimeter-wave radar in the context of space-based remote sensing is discussed. In addition, an overview of Silicon-germanium technology is presented, and the chapter concludes with a discussion of design challenges at millimeter-wave frequencies. In Chapter II, a brief history of radar technology is presented - the motivations leading to the development of the transmit-receive module for active electronically scanned arrays are discussed, and the critical components which reside in nearly every high-frequency transmit-receive module are introduced. In Chapter III, the design and results of a W-band single-pole, double-throw switch using SiGe p-i-n diodes are discussed. In particular, the design topology and methods used to achieve low-loss and high power handling over a wide matching bandwidth without sacrificing isolation are described. In Chapter IV, the design and results of a W-band low-noise amplifier using SiGe HBT's are discussed. The design methodologies used to achieve high gain and exceptional noise performance over a wide matching bandwidth are described. Concluding remarks and a discussion of future work are in Chapter V.
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Honda, Daniel Wanderley. "Controlador adaptativo por posicionamento de p?los e estrutura vari?vel aplicado ao controle de geradores e?licos baseados em m?quina de indu??o duplamente alimentada." Universidade Federal do Rio Grande do Norte, 2013. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15481.
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Previous issue date: 2013-09-13Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
In the last decade, the renewable energy sources have present a major propulsion in the world due to several factors: political, environmental, financial and others. Within this context, we have in particular the energy obtained through wind, wind energy - that has highlighted with rapid growth in recent years, including in Brazil, mostly in the Northeast, due to it s benefit-cost between the clean energies. In this context, we propose to compare the variable structure adaptive pole placement control (VS-APPC) with a traditional control technique proportional integral controller (PI), applied to set the control of machine side in a conversion system using a wind generator based on Double-Fed Induction Generator (DFIG). Robustness and performance tests were carried out to the uncertainties of the internal parameters of the machine and variations of speed reference.
As fontes de energia renov?veis t?m, na ?ltima d?cada, ganho uma grande propuls?o em todo o mundo devido aos mais diversos fatores: pol?ticos, ambientais, financeiros, entre outros. Dentro deste universo, temos, em especial, a energia obtida atrav?s do vento, energia e?lica - que tem se destacado com um crescimento vertiginoso nos ?ltimos anos, inclusive no Brasil, principalmente na regi?o Nordeste, devido ao seu custo-benef?cio entre as energias "limpas". Neste cen?rio, prop?e-se a compara??o do controlador por posicionamento de polos e estrutura vari?vel (VS-APPC) com o controlador proporcional integral (PI) aplicados em um sistema de convers?o de energia e?lica que utiliza um gerador de indu??o duplamente alimentado (Double-Fed Induction Generator- DFIG). Testes de robustez e desempenho foram realizados com incertezas nos par?metros da m?quina e varia??es de refer?ncia de velocidade
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Crémoux, Tatiana. "Physico-chimie aux interfaces de systèmes vitreux à charge d'espace." Thesis, Bordeaux 1, 2013. http://www.theses.fr/2013BOR14972/document.
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Le but de ce travail de thèse est de contrôler via un traitement de polarisation les propriétés physico-chimiques de surface des verres. Pour cela, l'implémentation d'une charge d'espace au sein de différents verres silicates et borosilicates a été caractérisée. Ces études comparatives ont montré que la déplétion des cations de l’anode vers la cathode induit l’apparition d’un champ électrique et des modifications structurales localisées. De plus, nous avons démontré que la formation d’un plasma entre l’anode et le verre pouvait être à l’origine de phénomènes d'échanges ioniques conduisant notamment à la formation d’entités azotées NO2/N2O4 piégées dans le verre. Par la suite, une étude des propriétés physico-chimiques des surfaces polarisées a été conduite. Les résultats préliminaires obtenus concernent l'influence de la charge d'espace sur (i) la mouillabilité, (ii) la chimie de surface et (iii) les réponses optiques de molécules adsorbéesThe purpose of this work is to control physicochemical properties of glasses surfaces using a thermal polarization treatment. For this, the implementation of a space charge layer has been characterized for various silicates and borosilicates glasses. These comparative studies have shown that cations depletion from anode toward cathode induces both an electric field and structural local changes. To go further, we demonstrated that there is a plasma formation between anode and glass surfaces which could be the cause of ionic exchange phenomena leading to the formation of nitrogen NO2/N2O4 entities entrapped inside glass network. Subsequently, physicochemical properties studies of polarized surfaces were performed. Preliminary results concerning the space charge influence on (i) surface wettability, (ii) surface chemistry and (iii) optical responses of adsorbed molecules on poled glass surface have been obtained
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Duffy, Michael James. "Small wind turbines mounted to existing structures." Thesis, Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/34765.
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Small wind turbines, and especially urban-mounted turbines which require no dedicated pole, have garnered great public enthusiasm in recent years. This enthusiasm has fueled widespread growth among energy conservationists, and estimates predict that the power produced nationally by small wind will increase thirty-fold by 2013. Unfortunately, most of the wind resources currently available have been designed for larger, rural-mounted turbines; thus, they are not well suited for this nascent market. A consequence of this is that many potential urban small wind turbine owners over-predict their local wind resource, which is both costly and inefficient. According to a recent study published by Encraft Ltd., small wind turbines mounted to buildings far underperformed their rural pole mounted counterparts.
As a proposed solution to this problem, this project introduces the concept of a Web-based Wind Assessment System (WWAS). This system combines all the necessary resources for potential urban small wind turbine customers into a single web-based tool. The system also presents the concept of a modular wind measurement system, which couples with the WWAS to provide real-time wind data measurements. The benefits of the system include its ease of use, flexibility of installation, data accessibility from any web browser, and expert advice. The WWAS prevents potential clients from investing in a system that may not be viable for their location.
In addition, a small wind turbine is designed in this project, which has a unique modular mounting system, allowing the same baseline wind turbine to attach to various structures using interchangeable mounting hardware. This includes such accessible urban structures as street lights, building corners, flag poles, and building walls, among others.
This design also utilizes concepts that address some of the challenges associated with mounting small wind turbines to existing urban structures. These concepts include: swept tip blades and lower RPM to reduce noise; vibration suppression using rubber shims; a netted duct to protect wildlife; and a direct-drive permanent magnet generator to ensure low starting torque.
Finally, the cost of this system is calculated using off-the-shelf components, which minimize testing and certification expense. This small wind turbine system is designed to be grid-connected, has a 6 foot diameter rotor, and is rated at 1 kW. This design features a unique modular interchangeable mounting system. The cost for this complete system is estimated to be $2,050. If a users' site has an average wind speed of 14 mph (6.5 m/s), this system will generate a return on investment in 8.5 years, leaving over 10 years of profit. The profit for this system, at this sample average wind speed, yields over $4,000 during its 20-year design life, which is a two-fold return on investment.
This project has implications for various stakeholders in the small wind turbine market, including designers, engineers, manufacturers, and potential customers. Equally important is its potential role in guiding our future national--even global--energy agenda.
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Utada, Satoshi. "Effect of a Prior Plastic Deformation during Heat Treatments on the Mechanical Properties of Ni-Based Superalloys for Turbine Blade Application Evolution of superalloy for turbine airfoil and development of recycling technology Platinum containing new generation nickel-based superalloy for single crystalline application Tensile, low cycle fatigue and very high cycle fatigue characterizations of advanced single crystal nickel-based superalloys Creep Property and Phase Stability of Sulfur-Doped Ni-Base Single-Crystal Superalloys and Effectiveness of CaO Desulfurization Evaluation and comparison of damage accumulation mechanisms during non-isothermal creep of cast Ni-based superalloys." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2020. http://www.theses.fr/2020ESMA0019.
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Les superalliages monocristallins base Ni sont utilisés pour la conception des aubes de turbines en raison de leur excellente durabilité à haute température. Lors de la production d'une aube de turbine, une déformation plastique (DP)inattendue peut être introduite dans le matériau. Dans cette étude, les matériaux monocristallins ont été pré-déformés entre les traitements thermiques de mise en solution et de revenu pour simuler la DP pouvant être rencontrée lors des étapes de production. Des tests mécaniques sur les matériaux pré-déformés ont été effectués pour comprendre l'effet de cette DP.Au cours des traitements thermiques de revenu du superalliage monocristallin AM1 pré-déformé, un grossissement des précipités γ′ plus rapide et une nucléation accélérée de pores ont été observés à proximité des bandes de glissement introduites lors de la DP à température ambiante. Au cours de la déformation par fluage de l’AM1 pré-déformé dans des conditions de haute température/basse contrainte (≥ 950 °C), les bandes à microstructure grossière sont des sites préférentiels d’accumulation du dommage de fluage induit par diffusion, induisant de la recristallisation et une réduction drastique des propriétés de fluage. Dans des conditions de basse température/haute contrainte (≤ 850 °C), le cisaillement de la microstructure est facilité dans les bandes à microstructure grossière et il réduit également les propriétés de fluage.La recristallisation n'est pas été observée dans des ces conditions de fluage à basse température car les mécanismes diffusifs sont ralentis. Ces résultats ont été confirmés via des essais de fluage sur des matériaux pré-déformés suivant différent chemin de pré-déformation (température, position de la DP dans le cycle thermique…). Le superalliage monocristallin CMSX-4 Plus a été testé de manière similaire à l'AM1 pour comprendre l'effet de la composition chimique. L'effet de la DP sur la microstructure de l'alliage est plus limité pour cet alliage par rapport à celui sur l’AM1. Par conséquent, la pré-déformation n'a pas montré de chute de la durée de vie pour le CMSX-4 Plus à des températures inférieures à 1050 °C. Par contre, pendant le fluage de CMSX-4 Plus à 1150 °C, la pré-déformation a montré un impact spectaculaire sur la durée de vie et la ductilité via les mêmes mécanismes que ceux observés pourl’AM1 à 1050 °C.Afin de régénérer les propriétés des superalliages monocristallins pré-déformés, un traitement thermique de restauration a été ajouté après la DP. Le traitement de restauration a permis de restaurer la microstructure après la DP à température ambiante avec succès, et les propriétés de fluage des matériaux restaurés sont équivalentes à celles de l'AM1 et duCMSX-4 Plus vierges de pré-déformationNi-based single crystal (SX) superalloys are used for turbine blade applications because of their high-temperature durability. During the production of a turbine blade, unexpected plastic deformation (PD) can be introduced to the material. In this study, SX materials were pre-deformed in between solution and aging heat treatments to mimic PD during production. Mechanical tests on the pre-deformed materials have been performed to understand the effect of the prior PD.During aging treatments of pre-deformed AM1 SX superalloy, faster coarsening of γ′ precipitates and enhanced void nucleation were observed in the vicinity of slip bands which were introduced by PD at room-temperature. During creep deformation of pre-deformed AM1 at high temperature/low stress conditions (≥ 950 °C), the microstructure coarsened bands act as diffusion induced creep damage accumulating paths, further triggering recrystallization and resulting in drastic reduction of creep properties. At low temperature/high stress conditions (≤ 850 °C), microstructure shearing was facilitated in the microstructure coarsened band and it decreased creep properties. Recrystallization was not observed at lower temperature creep because the diffusion damage was suppressed. These relationships have been explained by creep tests on pre-deformed materials prepared by different pre-deformation temperatures and heat treatment procedures.CMSX-4 Plus SX superalloy was tested similarly to AM1 to understand the effect of the chemical composition. Effect of pre-deformation on alloy’s microstructure was mild in CMSX-4 Plus compared to that in AM1. Therefore, the predeformation did no exhibit large creep life debit in CMSX-4 Plus at temperatures lower than 1050 °C. However, during creep of CMSX-4 Plus at 1150 °C, pre-deformation presented huge impact on creep life and ductility by the same mechanisms as the ones observed for AM1 at 1050 °C.In order to restore properties of pre-deformed SX superalloys, rejuvenation heat treatment was added after PD.Rejuvenation treatment successfully restored microstructure after PD at room-temperature, and creep properties of rejuvenated specimens were shown to be equivalent to that of original AM1 and CMSX-4 Plus without PD
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Herbinet, Vincent. "Les espaces du catholicisme francais contemporain : dynamiques communautaires polarisées et recompositions d’un paysage religieux éclaté : (1980-2013)." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE2040.
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Cette thèse vise à analyser dans la contemporanéité (1980-2013) la trajectoire du catholicisme, dans le sillage de la microhistoire, par l’étude de ses acteurs, de ses territoires et de ses communautés, des modes de gouvernement ecclésial. Nous mettrons en lumière le paradoxe du tissu de l’Eglise locale qui se dilate et se morcelle, mais aussi se contracte et se polarise, obligeant l’Ordinaire, dans son gouvernement, à penser un changement de paradigme : passer du défi de la proximité à celui de l’unité, compte tenu de la pluralité des communautés et des territoires associés. Nous étudierons, pour appuyer nos analyses, les diocèses de Rennes, Autun et Fréjus-Toulon. Un glissement de la logique d’enclos à la dynamique de pôles centralisateurs sera appréhendé, parfois en tensions, par les acteurs d’Eglise, à la lumière de quatre enjeux structurant l’argumentation : le « biotope » (rural/urbain), la diversité communautaire, le militantisme et la question de l’identité (statuts des clercs, coresponsabilité, modalités de l’évangélisation, communautarisme…).L’histoire et la géographie sociale permettront de renouveler les problématiques de l’appartenance spatiale et religieuse en partant d’interrogations sur le territoire selon des indicateurs précis : réseaux de fidèles et des militants, apport des nouvelles communautés (effectifs, choix pastoraux, gouvernement), options épiscopales en faveur de tel territoire ou tel groupe ecclésial… Pour l’historien, l’espace peut être considéré comme un outil heuristique, dans lequel des changements d’échelle se sont imposés dans le temps court. En délimitant nos recherches (1980-2013), nous voulons nous attarder à l’intérieur d’espaces qui ne possèdent plus la relative homogénéité que l’histoire leur prêtait avant le XXème siècle.Nos recherches s’inscrivent dans une structure en trois parties. La première partie se veut avant tout contextuelle, à la lumière de la postmodernité et de la sécularisation qui modifient les modes d’appartenance à une religion déclarée par beaucoup en soins palliatifs. Nous analyserons les liens étroits entre le catholicisme et ses modes d’insertion territoriale (rural/urbain) à partir de nos diocèses de référence. Nous présenterons les dé/recompositions des formes de militantisme dans le diocèse de Rennes, terreau d’Action catholique de plus en plus stérile et laissant la place à une militance familialiste très urbaine.La seconde partie de la thèse abordera les enjeux de la gouvernance ecclésiale dans les trois diocèses d’étude. Nous étudierons, dans le temps court, l’évolution du « munus regendi » des évêques et des prêtres avec le croisement des générations, avec le principe de coresponsabilité et le développement différencié selon les diocèses du diaconat permanent et des laïcs en mission ecclésiale. Nous développerons tout particulièrement le cas toulonnais pour lequel peu d’études approfondies ont été réalisées.Enfin, la troisième partie mettra l’accent sur la problématique du développement croissant d’un catholicisme attestataire polarisé en quête de visibilité. Nous analyserons la genèse du Renouveau et sa trajectoire dans le diocèse de Rennes. Nous nous pencherons particulièrement sur la communauté de l’Emmanuel, sur sa promotion de la nouvelle évangélisation et l’intégralisme de ses modes pastoraux. Ensuite, fort d’une certaine fécondité sacerdotale et d’un dialogue chaotique avec Rome (Motu proprio en 1988 et 2007), la galaxie traditionaliste très hétéroclite reste le cadre de mutations contemporaines que nous étudierons dans les diocèses de Rennes et d’Autun. Enfin, nous changerons d’échelle en nous focalisant sur la ville-sanctuaire de Paray-le-Monial, pôle militant et laboratoire incubateur d’un « nouveau catholicisme », sur l’articulation entre les différents territoires (ville, sanctuaire, paroisse) et les acteurs en placeThis thesis aims at analysing, in the contemporary world (1980-2013), the trajectory of catholicism, in the wake of microhistory, through the study of its actors, its territories and its communities, the modes of ecclesial government. We will highlight the paradox of the fabric of the local Church which expands and fragments, but also contracts and polarizes, forcing the Ordinary, in his government, to think of a paradigm shift: from the challenge of proximity to the one of unity, taking into account the plurality of communities and associated territories. To support our analyses, we will study the dioceses of Rennes, Autun and Frejus-Toulon. A shift from the logic of enclosures to the dynamics of a centralizing pole will be apprehended, sometimes in tension, by Church actors, in the light of four issues structuring the argument: « biotope » (rural/urban), community diversity, activism and the question of identity (status of clerics, co-responsibility, modalities of evangelization, communautarism...).History and social geography will enable us to renew the problems of spatial and religious belonging by starting from questions about the territory according to precise indicators: networks of the faithful and militants, the contribution of new communities (numbers, pastoral strategies, government), episcopal options in favour of a particular territory or ecclesial group... For the historian, space can be considered as a heuristic tool, in which changes of scale have been imposed in short time. By delimiting our research (1980-2013), we want to focus on the interior of aeras that no longer possess the relative homogeneity that history lent them before the 20th century.Our research are presented in a three-part structure. The first part is intended above all to be contextual, in the light of postmodernity and secularization, which modify the modes of belonging to a religion declared by many in palliative care. We will analyse the close links between Catholicism and its modes of territorial integration (rural/urban) from our dioceses of reference. We will present the recompositions of the forms of militancy in the diocese of Rennes, a breeding ground for Catholic Action that is increasingly sterile and leaving room for very urban familyist militancy.The second part of this thesis will address the issues of ecclesial governance in our three dioceses of study. We will study, in the short time, the evolution of the « munus regendi » of bishops and priests with the crossing of generations; with the principle of co-responsibility and the differentiated development according to the dioceses of the permanent diaconate and of the laity in ecclesial mission. We will particularly develop the Toulon case for which few in-depth studies have been carried out.Finally, the third part will focus on the problem of the growing development of a polarized Catholic witness in search of visibility. We will analyze the genesis of the Renewal and its trajectory in the diocese of Rennes. We will look particularly at the Emmanuel community, its promotion of the new evangelization and the fundamentalism of its pastoral modes. Then, with a certain priestly fruitfulness and a chaotic dialogue with Rome (Motu proprio in 1988 and 2007), the very heterogeneous traditionalist galaxy remains the framework of contemporary mutations that we will study in the dioceses of Rennes and Autun. Finally, we will change scale by focusing on the city-sanctuary of Paray-le-Monial, militant pole and laboratory incubator of a « new Catholicism », on the articulation between the various territories (city, sanctuary, parish) and the actors in place
La modernidad desafía "parroquia civilización". Los cambios en espacial e institucional llevada a cabo por la Iglesia católica, entre ellos diócesis, son simples adaptaciones renovadas o por el contrario, inauguran un proceso de desarrollo en el centro de nuevas áreas de distribución, en particular con el creciente impacto de los nuevos jugadores? Las iglesias se vacían todas partes en Francia, pero las comunidades y diócesis han recuperado algunos lugares para hacer los pilares de las nuevas formas de práctica religiosa, si es posible, la supervivencia no sólo de la institución, sino también la transmisión de la fe. ¿Cuál es el proceso? ¿Es sostenible en el tiempo? ¿Con qué herramientas?
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黃怡錚. "Generating Standing-up Motion from Arbitrary Initial Poses." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/64928332866880730852.
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碩士國立交通大學
網路工程研究所
98
We present an efficient standing-up motion generation approach that utilizes a motion planning algorithm to connect a given posture to a closest posture in a database of standing-up motions. Our approach is composed of three stages: First, selecting one of the most suitable posture from the database and initial posture connects to it; Second, planning a motion which can connect the initial posture and the selected end posture; Third, refining the planned motion by smoothing and dynamics filtering. Our experiments demonstrates that our algorithm can successfully generate physically-correct standing-up motion from arbitrary initial postures in environments without- and with-obstacles.
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Zhu, Eric Yi. "Nonlinear Parametric Generation in Birefringent Poled Fibers." Thesis, 2010. http://hdl.handle.net/1807/25714.
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Conventional step-index silica fibers do not possess a second-order optical nonlinearity due to symmetry concerns. However, through the process of poling, the generation of a frozen-in DC field $E^{DC}$, and in turn, a non-zero second-order nonlinearity $\chi^{(2)} = 3\chi^{(3)}E^{DC}$, can be created in optical fibers. In this thesis, I measure the individual $\chi^{(2)}$ tensor elements of birefringent periodically poled fiber via second-harmonic generation and sum-frequency generation experiments. The symmetry of the $\chi^{(2)}$ tensor is consistent with that of the $\chi^{(3)}$ for isotropic media. This is the first study that characterizes all the $\chi^{(2)}$ tensor elements in birefringent poled fiber. Furthermore, I investigate the intermix of the $\chi^{(2)}$ tensor elements by twisting the fiber, which results in the generation of new second-harmonic signals not observed in untwisted fiber. The conversion efficiencies and spectral positions of these new signals can be varied by twisting the fiber.
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Li, Jun-Ying, and 李俊瑩. "Quasi-Phase-Matching Second Harmonic Generation Green Laser in Periodically-Poled MgO:LiNbO3." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/46843374439246298234.
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碩士國立臺灣大學
光電工程學研究所
97
This thesis is organized into three parts：(a) The theory of quasi-phase-matching (QPM) and second harmonic generation (SHG), (b) The fabrication techniques of periodically poled magnesium-oxide-doped congruent lithium niobate(MgO:LiNbO3), (c) Optical measurement and characteristic analysis of periodically-poled MgO:LiNbO3 laser chips for producing second harmonic generation (SHG) of green laser. First, the theory of QPM and nonlinear optical generation will be introduced. In the second part, the fabrication technique improvements are based on electric poling method of congruent lithium niobate. This method leads to the realization of periodically poled QPM structures of 0.5 mm thick MgO:LiNbO3 substrates. The smallest periods achieved in this work are (i) 6.75 um for the 1st 2D、(ii) 13.8 um for the 2nd 1D and (iii) 6.9 um for the 1st quasi-1D QPM device. These chips are suitable for producing SHG green laser. Finally, a green laser made of 0.8 mm long periodically poled MgO:CLN are tested by a pulsed 1064 nm laser of 100 MW/cm^2. The device exhibits a broad temperature acceptance width of 30 ℃ and SHG efficiency of 10.6 %, which yield 26.4 mW green at 250 mW 1064 nm pump.
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Chia-Sheng, Hsieh, and 謝佳昇. "Process development of soft proton-exchangedwaveguides in periodically poled MgO:LiNbO3 forsecond harmonic generations." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/37358932878984584478.
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碩士國立中央大學
光電科學研究所
99
Integrated miniaturized laser components has a lot of applications，such as blue laser light source for bio-medical、laser printing、optical storage and retrieval and measurement systems have many applications; green laser light source in the data Printing、laser displays、precision machining、high-resolution printing devices also has many applications。 we try to develop a fabrication method of a quasi-phase-matching (QPM) second-harmonic generator in a low-loss soft proton exchange optical-waveguide for achieving a high-efficiency laser based on a 5 mol. % MgO:LiNbO3 characterized by high optical nonlinearity and high optical damage resistance。In the experiment，light source with three different wavelength in 1550nm、1064、808nm incident three different MgO:LN SPE waveguide to generate second harmonic generation in 775nm、532nm、404nm three different light。 In the theoretical simulation，we have successfully used diffusion-type ion exchange (ion exchange equation) to establish the soft proton exchange waveguide diffusion model，the diffusion distribution curve and the actual measured results have a very similar distribution。 III In the experimental measurements，we have successfully made the soft proton exchange waveguide，using XRD diffraction identified as a single phase，and the methods used Fabry-perot to measure propagation loss is about 1.4dB/cm。In the Blue light measurement，the maximum blue light output is about 0.2mw and the conversion efficiency is about 48% / W; second harmonic in the red light, the red light measurement，the maximum red light output is about 320nw and the conversion efficiency is about 48% / W; in the green light measurement，the phase matching temperature can not be found。 SHG temperature phase-matching bandwidth in green light is too small to be found in the experiment by the theoretical calculation。The reason of the low conversion efficiency in red light generation due to the bad mode overlapping integral between the fundamental frequency and second harmonic frequency。
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Shen, Shin-Yi, and 沈欣怡. "Generation of high order harmonics by sum frequency mixing in periodically poled structure." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/07707191602111975618.
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碩士國立清華大學
光電工程研究所
100
This research focuses on simulating and designing a chip with periodic poled congruent grown lithium tantalite to achieve the goal of multiple harmonics generation simultaneously so as to expand the range of spectrum of the laser wavelength. With the technique of waveform synthesis, this chip will allow us to obtain ultrashort subfemtosecond pulses. It will make the ultimate goal of controlling electronic motion closer to reality. The thesis includes a short summary of the theory of optical parametric oscillator (OPO) and quasi-phase matching (QPM), simulation and design of the nonlinear crystal, measurement results and analysis. At last, there is an attachment about the conversion efficiency measurements of crystals designed for a programmable full-spectrum laser wavelength conversion system. In the first part, we introduce frequency conversion, OPO and QPM. In the part of measurement and design, we calculate the phase-matched periods, test the fan-out chips and simulate conversion efficiencies to decide on the periods and lengths of every section on a QPM chip that can be sued for multiple harmonics generation. We successfully designed and fabricated a chip that can generate seven harmonics. In the last part, we describe the measurement of the conversion efficiencies of sum frequency generation (SFG) and difference frequency generation (DFG) of a CW fiber laser and a 1550 nm laser diode for the purpose of building a programmable tunable laser source. The conversion efficiency of DFG is 1.21% which is higher than any reported in the literature.
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Chang, Wei-Lin, and 張維麟. "Tunable Pulse Laser Generation from 1.3μm to 1.8μm by Periodically Poled Lithium Niobate." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/88714148054792292730.
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碩士國立臺灣大學
物理研究所
100
In bio-materials, confocal fluorescence(CF) microscopy reaching penetration depth over 100μm is difficult because of turbidity of soft-material and scattering of complex structure. Based on scattering theory, the longer wavelength, the lower scattering effect. We can increase penetration depth by using larger wavelength with less scattering. Because of double frequency of excitation, two-photon fluorescence (2PF) microscopy and second harmonic generation (SHG) microscopy can observe more deeper than 500 μm, even to reach 1 mm . Therefore, a bio-imaging system combined with an infrared (IR) source is required. However, only special wavelength can excite to fluorescence of bio-materials or stains, IR sources are not commonly applied to fluorescence microscopy. On the other hand, for imaging, SHG microscopy is free on excitation wavelength selection as far away resonance frequency. In our experiment, we expect to generate multi-frequencies laser source in IR. By optical parametric generation (OPG), we easily generate IR laser source on periodically poled lithium niobate (PPLN), which is tunable frequency, high intensity and ultrafast pulse duration. Commonly, in our system, the power of the tunable source is at least 60 mW from 1315 nm to 1650 nm, and the highest is over 1 W. The tunable IR source properly apply to SHG microscopy. Combined OPG with SHG microscopy, we can achieve spectral imaging.
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Shih, Chih T'sung, and 石志聰. "Fabrication of Quasi-Phase-Match Second-Harmonic-Generation Device on Periodically-Poled -Y cut MgO-Doped LiNbO3 for Blue Light Generation." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/55191359446346385208.
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Kai-Wei, Chang, and 張凱為. "Towards Collinearly phase-matched THz-wave Parametric Generation in Multimode Periodically Poled Lithium Niobate waveguides." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/08503128049287758017.
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碩士國立清華大學
電機工程學系
92
Terahertz (THz)-wave’s generation and detection have gained increasing interests from fundamental and applied perspectives. Nonlinear wavelength mixing has been one of the most effective techniques to generate low-power coherent THz radiations. Recently, periodically poled lithium niobate (PPLN) has become the nonlinear-optical material of the choice, which provides the compensating wave-vector to achieve the collinear phase-matching condition. We first report high-efficiency, collinearly phase-matched terahertz-wave parametric generation (TPG) in a 6-cm long, 780-�慆 thick PPLN waveguides pumped by a ~150 �寙/pulse actively Q-switched laser at 532-nm wavelength and by a ~60 �寙/pulse passively Q-switched Nd:YAG laser at 1064-nm wavelength. We measured 80-�慆 and 330-�慆 terahertz wavelengths from the 532-nm and 1064-nm pumped PPLN crystals with domain periods of 71.5 �慆 and 67 �慆, respectively. Due to the long gain length and the waveguide-mode confinement, sub-nJ terahertz radiation at 80-�慆 wavelength was detected by a pyrodetector with 100-�寙 pump energy at the 532-nm wavelength. Furthermore, we try to accomplish the experiment of backward terahertz-wave parametric oscillation (TPO) in a 4-cm long and 780-�慆 thick PPLN waveguides having a domain inversion period of 44-�慆 and 32-�慆 pumped by a ~250 �寙/pulse actively Q-switched laser at a 532-nm wavelength. From the observed signal output, the threshold energy of the backward oscillation was ~30 �寙. The waveguide confinement of the THz wave was confirmed by comparing the signal spectrum of 1064-nm pumped PPLN crystals with 500-�慆 and 1000-�慆 thickness.
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Wei-ZeHua and 花瑋澤. "Development of Periodically-Poled Lithium Niobate with Applications in Second Harmonic Generation and Diffraction Gratings." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/21300367642220875413.
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碩士國立成功大學
微電子工程研究所
102
We successfully use the high voltage poling with liquid electrode insulation method to fabricate a periodically poled lithium niobate (PPLN). The inverted domain gratings with periods of 60, 15.5, and 6.7μm so designed have. We have successfully used the hydrofluoric acid (HF) etching and optical diffraction techniques to verify the periodicity of inverted domains. The HF etching can be used to reveal the inverted domains microscopically because the etch rates in the +Z and –Y faces are substantially faster than those in the –Z and +Y faces, respectively. On the other hand, optical diffraction offers another alternative method to verify the existence of poled domains by evaluating the corresponding diffraction patterns. For the second harmonic generation, we have successfully demonstrated of using a 1064nm fiber laser for frequency doubling to generate 532 nm green light at room temperature.
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CIOU, BAO-SIAN, and 邱寶賢. "Process development of proton-exchanged waveguides in periodically poled MgO:LiNbO3 for green second harmonic generation." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/02231833485940914196.
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碩士國立中央大學
光電科學研究所
98
LiNbO3 has higher nonlinear, electro-optic coefficient and ferroelectric property. We could fabricate a single chip with more capability. By using ferroelectric property and lithography, we can develop the periodically inverted domain, Using the nonlinear coefficient, we can generate any wavelength of laser. Using the electro-optic coefficient, we can produce Q-switched pulse laser. For reduce the effect of photorefractive, we choose MgO:LiNbO3 crystal to improve it. Appling the theory of quasi-phase matching and the fabrication of periodically poled, and combination with low loss optic waveguide, we can get high efficiency of second-harmonic generation (SHG) for green light laser. We successfully fabricate these 18 um 3rd period domain inverse with 5mol/% Mg-doped Linbo3 substrate, the duty cycle about 50%. This paper makes a comparison among three kind of waveguide, Anneal proton exchange, Soft proton exchange, Reverse proton exchange. Conversion efficiency of soft proton exchange waveguide is about 20%W^(-1) cm^(-2), anneal proton exchange waveguide is about 30%W^(-1) cm^(-2). Due to the depth of the soft proton exchange waveguide not quite enough, coupling efficiency become low. If we increase proton exchange time, can improve this situation.It is predicted that conversion efficiency of SPE waveguide would better than APE waveguide. There is a dead layer result in APE waveguide fabrication process, meanwhile destroy nonlinear coefficient. Due to the bad fiber to waveguide coupling efficiency, therefore scattering of fundamental light and noise were detected to reduce it in the measurement. we will have better result by improving the measurement. In fabrication the reverse proton exchange waveguide, it will cause the crystal-destroyed. We supposed that the more hydrogen ions accumulate the more crack will occur in crystal when the annealing processed therefore, we proposed some of new fabrication method to improve this situation
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Chen, Chieh-Ting, and 陳玠廷. "Waveguide Faricaiton on Lithium Niobate and Third-harmonic Generation in Periodically Poled Lithium Niobate Waveguides." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/26061756428781090844.
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碩士國立臺灣大學
光電工程學研究所
90
In this thesis, we report the fabrication of channel waveguides on LiNbO3 and PPLN. The second harmonic generation and third harmonic generation in such waveguides are also discussed. Here, two methods were used for waveguide fabrication. One was the annealed proton exchange (APE) method with benzoic acid melt and the other was the proton exchange vapor (PEV) method with benzoic acid vapor. The characteristics of the waveguides showed the dependencies on guiding width, proton exchange time, annealing time and wavelength. With these two methods, single-mode and multi-mode waveguides were fabricated on LiNbO3 and periodically poled LiNbO3 (PPLN) under different fabrication conditions. Second-harmonic and sum-frequency generations with a 1560 nm femtosecond source were implemented in the fabricated waveguides. The same nonlinear processes were also implemented on bulk PPLN for comparison. Since the effective extraordinary refractive index was different in a waveguide, the phase-matching condition based on the Sellmeier equation was no longer accurate. Also, because the propagation constants varied among single-mode and multi-mode waveguides, their phase-matching conditions were different. Therefore, the results of nonlinear wavelength conversion were slightly different between bulk PPLN and waveguides of different geometries.
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Bhatt, Ajay. "Generation of all-pole 2-D digital filters from the combination of all-pass filters." Thesis, 2007. http://spectrum.library.concordia.ca/975440/1/MR34581.pdf.
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Two-dimensional digital filters are applied in signal processing and pro-imaging process, as well as communication systems where the frequency domain characteristics of digital filters are required to be adjustable. The main objective of this thesis is to propose a new technique for designing all-pole 2-D digital filters with variable magnitude characteristics. In this thesis, 2-D digital filters starting from the identical analog 1-D second-order Butterworth lowpass filter are generated through the combination of all-pass filters in Category A and Category B. A new type of all-pole 2-D analog lowpass filter is designed through the combination of all-pass filters. The transfer functions of these filters are verified for stability. The 2-D analog lowpass filter has been transformed to the digital domain by applying generalized bilinear transformation. The design of the 2-D digital lowpass filter gives rise to 2-D digital highpass, bandpass and bandstop filters in Category A and Category B. The 2-D digital highpass and bandstop filters have been designed from the 2-D lowpass filter using appropriate generalized bilinear transformation in both the categories. The 2-D digital bandpass filter has been obtained by a combination of the 2-D digital lowpass and highpass filters in both the categories. The effect of the coefficients of the generalized bilinear transformation on the 2-D digital filter's transfer function is studied in detail for Category A and Category B. In the end, an application of the proposed 2-D lowpass filter in Category A and Category B is illustrated in image processing. The designed 2-D low-pass filter has been used to reduce the effect of additive white Gaussian noise on digital images in both the categories
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Wang, Chun-lin, and 王俊霖. "Single aperiodically poled lithium niobate for simultaneous laser Q-switching and optical parametric generation in a Nd:YVO4 laser." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/08345317865791381606.
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碩士國立中央大學
光電科學研究所
98
Optical parametric oscillators (OPOs) can produce wavelength tunable coherent light sources and have been widely used in various applications including the remote sensing, spectroscopy, nonlinear optics, range finder, optical communications, and bio-medicine. Several high-efficiency intracavity wavelength converters have been developed via the use of a nonlinear crystal in an acousto-optic or electro-optic (EO) Q-switched solid-state laser. However, a more compact integrated system performing the same device functions is still rare. In this thesis, we have devoted to integrate two device functions in a monolithic LiNbO3 crystal. These two devices are an EO Q-switching and an optical parametric generator (OPG). An aperiodically poled lithium niobate (APLN) crystal has been designed and fabricated in this work to simultaneously satisfy the phase-matching conditions required for functioning the two devices. We further inserted this APLN crystal in a Nd:YVO4 laser system to simultaneously function as a laser Q switch and an intracavity optical parametric amplifier. We have successfully demonstrated an efficient EO Q-switched IOPO in a compact diode-pumped 1064-nm Nd:YVO4 laser achieved using a single intracavity APLN.The APLN device was designed using the SA optimization method. It can simultaneously function as an EO Q-switch and an OPG.The OPO efficiency achieved with the system using the APLN device has been ~1.67 times higher than that with a system using a cascade PPLN device of the same device length and under the same system operating conditions. When the intracavity APLN was driven with a ~ 360-V pulse train at 1 kHz, we observed ~ 33 % energy depletion in fundamental laser pulses, yielding ~ 5-ns, ~ 1029W peak-power 1550-nm OPO laser pulses from this compact laser system pumped at 8.4-W diode power.
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Chen, Po-Chao, and 陳柏超. "Design and Fabrication of Annealed-Proton-Exchanged Waveguides on Periodically-Poled LiTaO3 for Quasi-Phase-Match Second-Harmonic-Generation." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/81131635547334180892.
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Yeh, Yen-jiun, and 葉彥均. "Quasi-Phase-Match Second-Harmonic-Generation of Blue Light on First Order Periodically Poled Lithium Tantalate with Annealed-Proton-Exchange Waveguide." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/45743326609336995256.
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Tremblay, Olivier. "La jeunesse comme enjeu politique au cinéma états-unien contemporain : pour une polis audiovisuelle." Thèse, 2015. http://hdl.handle.net/1866/13498.
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Cette recherche s’intéresse aux propriétés politiques du médium audiovisuel, et plus spécifiquement de la pratique cinématographique, devant un problème concret : la marginalisation de la jeunesse dans la société américaine contemporaine, symptomatique d’une perte d’espoir en l’avenir. Guidé par la théorie politique de Hannah Arendt, l’argumentaire consiste d’abord en deux analyses filmiques : une première de Kids (1995), réalisé par Larry Clark, porte sur l’invisibilité sociale de la jeunesse et la faculté du médium audiovisuel à confronter le spectateur. La seconde se penche sur le pouvoir systématisé auquel sont soumis les jeunes dans une institution scolaire bureaucratique, tel qu’il est mis en scène dans Elephant (2003) de Gus Van Sant, et interroge la capacité du médium à susciter la pensée chez le spectateur. Dans un troisième temps, une réflexion plus globale sur la situation actuelle de la culture cinématographique au sein du domaine audiovisuel dominé par le divertissement de masse explore la possibilité d’une polis audiovisuelle. Cette troisième et dernière partie reprend les thèmes soulevés dans les précédentes dans une perspective politique basée directement sur la pensée d’Arendt : ils donnent lieu aux questions de l’apparaître et de la durabilité du monde, qui sont les principales fonction de la polis, ainsi qu’à la question du rôle du spectateur.This research is about the political properties of the audiovisual media, focusing on cinema as a specific practice, in front of a concrete problem: marginalized youth in contemporary American society, which is symptomatic of a loss of hope for the future. Guided by Hannah Arendt’s political theory, the arguments start with two film analyses: a first one of Larry Clark’s Kids (1995) concerns the social invisibility of youth, and audiovisual media’s faculty to confront the spectator. The second one takes a look at the systematized power to which youths are submitted in a bureaucratic educational establishment, as it is featured in Gus Van Sant’s Elephant (2003), and examines media’s capacity to bring the viewer to think. Third and last, a more overall reflection on the current situation of film culture within the audiovisual field dominated by mass entertainment explores the possibility of an audiovisual polis. This last part pursues the themes discussed in the two former ones in a politic perspective, directly based on Arendt’s thoughts: they lead to considerations on appearance and durability of the world, which are the main functions of the polis, as well as considerations on the spectator’s role.
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Sue, Wei-Bo, and 蘇瑋柏. "Quasi-Phase-Matched Second-Harmonic-Generation of Blue Light on Periodically Poled MgO doped Y-cut Lithium Niobate with Annealed-Proton-Exchange Waveguide." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/93225963861572428311.
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Huang, Yao-Hsien, and 黃耀賢. "Monolithic aperiodically and periodically poled lithium niobate for simultaneous laser Q-switching and intracavity sum-frequency generation in a dual-wavelength Nd:YVO4 laser." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/95673719412115824709.
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碩士國立中央大學
光電科學研究所
100
Abstract Bragg condition is very sensitive to incident wavelength. With this characteristic, we can diffract wavelength with appropriate Bragg structure. In this letter, we first design an aperiodic structure with the help of simulated anneal algorism which compensates reciprocal vectors of dual wavelength emitted in Nd doped solid state laser system. Lithium Niobate is a great electro-optic crystal. With the high electric field poled, we can generate the structure we calculate previously on LN crystal. Thus, a 25 mm long, 5 mm in width and thickness of 0.5 mm aperiodic poled Lithium Niobate Bragg diffraction cascade 15mm long periodical poled Lithum niobate sum frequency Generation device is fabricated successfully. In experiment, we measured the high diffraction efficiency both on 1064 nm and 1342 nm, 96% and 87% respectively, at –250 and -350 volt applied voltage. Furthermore, we put our chip into the Nd:YVO4 slid sate laser system and applied a periodic electric field to the chip, we can turn it into a cavity Q-switch device. With the sum frequency crystal BIBO, we can generate narrowand high peak power 593 nm output from dual emission wavelength of Nd 1064 nm and 1342 nm. In results, the yellow-orange light output with the pulse width of 8 ns and peak power of 430 W under 8.142 W of Nd absorption power at tempature 73℃.
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Chou, Pin-yu, and 周䓵譽. "Monolithic two dimension aperiodically poled lithium niobate for simultaneous laser Q-switched and intracavity sum frequency generation in a dual wavelength Nd:YVO4 laser." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/59303410051352864747.
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碩士國立中央大學
光電科學與工程學系
102
Compact, high-repetition-rate pulsed visible coherent light sources are attractive for many applications, such as biomedicine, remote sensing, astronomy, and displays. The Q-switched all-solid-state laser technique can be a promising approach to attain such light sources. Moreover, due to the high nonlinearity and highly engineerable characteristics of the quasi-phase-matching(QPM) material, a device as simultaneous a Q-switch and wavelength converter can be realized in a two-dimensional aperiodically poled lithium niobate (APPLN). In this thesis, we have designed and fabricated a unique 2D APPLN device integrating the functionalities of the Q-switch for two laser lines(1064nm and 1342 nm) simultaneously and sum frequency generator in a Nd:YVO4 laser system to generate pulsed yellow-orange laser, the such device was designed by aperiodic optical superlattice(AOS) technique and optimized by simulated annealing(SA) method. In operation, 350 volts at repetition rate of 1 KHz drove the device, while the diffraction efficiencies of 1064 nm and 1342 nm of 60 % and 55 % were measured, respectively. At diode pump power of 5.7 watts, a yellow-orange pulse with pulse width of 8.4 ns, bandwidth of 0.4 nm, and peak power of 512 can be obtained, meanwhile, the peak-to-peak fluctuation of 8.9% was also found.
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Cajiao, Velez Felipe. "Engineering and Control of Quantum Processes by Short Laser Pulses." Doctoral thesis, 2016. https://depotuw.ceon.pl/handle/item/1854.
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