Disertacija skirta nepusiausvirųjų krūvininkų dinamikos tyrimams SiC, GaN bei deimantuose naudojant šviesa indukuotų dinaminių gardelių, diferencinio pralaidumo, diferencinio atspindžio bei fotoliuminescencijos metodikas. Taipogi pristatomos naujos sugerties koeficiento matavimo bei gyvavimo trukmės mikroskopijos metodikos. Tyrimai atlikti plačiame nepusiausvirųjų krūvininkų tankių ir temperatūrų intervale esant vienfotoniam bei dvifotoniam sužadinimui. Nustatytas stiprus krūvininkų difuzijos koeficiento priklausomumas nuo krūvininkų tankio ir temperatūros. Jis paaiškintas fononine sklaida, krūvininkų tarpusavio sąveikos procesais bei išsigimimu. Buvo nustatyta, kad netiesiatarpiuose SiC ir deimanto puslaidininkiuose prie mažų sužadinimų rekombinacija yra ribota taškiniais bei paviršiniais defektais, o GaN dominuoja rekombinacija ant tarpkristalitinių ribų. Taipogi pasireiškė netiesinis Ože rekombinacijos procesas, kuris prie žemų sužadinimų buvo sustiprintas kulonine sąveika bei susilpnintas prie didelių dėl elektron-fononinės sąveikos ekranavimo bei išsigimimo. Fotoliuminescencijos efektyvumas parodė, kad spindulinės rekombinacijos koeficientas GaN mažėja nuo sužadinimo, tuo tarpu SiC jis nuo žadinimo nepriklauso. Kompensuojančių defektų (aliuminio SiC ir boro deimante) koncentracijos ir aktyvacijos energijos nustatytos stebint jų sąlygotos sugerties įsisotinimą bei jų signalo relaksacijos spartos priklausomybę nuo temperatūros. / The thesis is dedicated to investigation of carrier dynamics in SiC, GaN and diamond by using light-induced transient gratings, differential transmittivity, differential reflectivity and photoluminescence techniques. Also new absorption coefficient measurement and carrier lifetime microscopy techniques are presented. The experimental studies were performed in a wide range of excess carrier densities and temperatures under single- and two- photon excitation conditions. Strong diffusion coefficient temperature and injection dependences were determined. They were explained by phonon scattering, inter-carrier interaction processes and degeneracy. It was determined, that in indirect-gap SiC and diamond semiconductors at low injections lifetime is limited by point and surface defects, while in GaN recombination on grain boundaries prevails. Also nonlinear Auger recombination coefficient was observed. It was Coulombically enhanced at low injections and screened at high ones. Photoluminescence efficiency revealed radiative recombination coefficient reduction with injection in GaN. On the other hand, in SiC radiative coefficient was injection independent. Compensating defect (aluminum in SiC and boron in diamond) concentrations and activation energies were determined from their absorption saturation and recovery rate temperature dependences.

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This dissertation is part of the line of "Education, Knowledge and Professional Development" of the Program of Post-Graduation in Education (PPGE) of Federal University of Santa Maria (UFSM). In this work brings to the discussion a resource that can be used in the Initial Education of Biological Sciences Teachers, the Diary of the Pedagogic Practice (DPP). DPP is an instrument in which teachers register their planning following by the comments on the implementation about what is being developed in classroom, allowing a more organized organization and reflection in practical situation. It also allows the teachers to investigate, analyze and revise relative subjects to their work that frequently remain unseen to their own perception, due to the fact they are involved in the daily actions of work. The work was developed with 13 academics of the Biological Sciences Course, intending to understand how the process of reflection of their own practice occurs for these academics starting from the use of DPP. For the analysis of the diaries, I make use of the Speech Analysis, as well as a semi-structured interview. In elapsing of the work I could conclude that the diary can be an instrument to help the academics in the apprenticeship process, seeking to contribute for their personal and professional growth. Starting from the reading of the diaries it was possible to notice an evolution in the trainees' work. / Esta dissertação faz parte da linha de Formação, Saberes e Desenvolvi-mento Profissional do Programa de Pós Graduação em Educação (PPGE) da Universidade Federal de Santa Maria (UFSM).Neste trabalho trago à discussão um recurso que pode ser utilizado na Formação Inicial de Professores de Ciências Biológicas, o Diário da Prática Pedagógica (DPP). O DPP é um instrumento no qual os professores registram seus planejamentos seguidos dos comentários sobre sua implementação em sala de aula, permitindo uma organização e reflexão mais orientada sobre o que se desenvolve em situação prática. Permite também que os professores investiguem, analisem e revisem questões relativas ao seu trabalho, que freqüentemente permanecem ocultos à sua própria percepção, devido ao fato de estarem envolvidos nas ações cotidianas de trabalho. O trabalho foi desenvolvido com 13 acadêmicos do curso de Licenciatura em Ciências Biológicas, buscando compreender como se dá o processo de reflexão da própria prática por estes acadêmicos a partir da utilização do DPP. Para a análise dos diários, utilizei a Análise de Discurso, bem como uma entrevista semi-estruturada. No decorrer do trabalho pude concluir que o diário pode ser um instrumento para auxiliar os acadêmicos no processo de estágio, visando contribuir para o seu rescimento pessoal e profissional. A partir da leitura dos diários foi possível perceber uma evolução no trabalho dos estagiários. O diário é um instrumento que pode contribuir para a reflexão das práticas pedagógicas, pois, a partir dele, podemos identificar crenças, problemas, representações e teorias implícitas que os estagiários possuem, podendo desta forma ser uma alternativa a ser utilizada na formação inicial de professores.

Made available in DSpace on 2014-10-09T12:38:06Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:53Z (GMT). No. of bitstreams: 1 05639.pdf: 6476184 bytes, checksum: 3037d7c0ce96c51e46c15baa5bdd114c (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:92/01672-4

O principal objetivo deste estudo foi avaliar a refletância e sua influência no comportamento térmico de tintas refletivas e tintas convencionais aplicadas em telhas de fibrocimento para cobertura de habitações brasileiras. Foram realizados ensaios em laboratório de determinação de cor e de brilho por medida instrumental e determinação da refletância por análise espectrofotométrica em películas. Para o estudo do comportamento térmico foram realizados ensaios de simulação em laboratório com corpos-de-prova expostos à radiação infravermelha emitida por lâmpadas e de exposição à radiação solar em campo através de protótipos com monitorização da temperatura durante as exposições. Os resultados dos ensaios de determinação de cor e de brilho mostraram que as pinturas refletivas e convencionais realmente apresentaram cores correspondentes. Os resultados de refletância mostraram que as pinturas refletivas apresentaram valores de refletância superiores em relação às tintas convencionais, o que foi comprovado pela temperatura medida nos ensaios de exposição à radiação infravermelha e radiação solar. A conclusão do estudo é que as tintas refletivas têm potencial para redução da temperatura superficial da telha de fibrocimento e que é necessária uma continuidade do estudo de durabilidade e do desempenho térmico de tintas refletivas coloridas. / The main purpose of this study was to investigate the effect of reflective colored paints and conventional colored paints applied on fiber cement corrugated roofing sheets, proving whether both type of paints can present different reflection characteristics in the infrared solar radiation and high thermal performance. Color and gloss were measured by instrumental methods and reflectivity (reflection coefficient) was measured using spectrophotometers equipped with integrating spheres in free paint films. In order to investigate the thermal performance of reflective and conventional paints, simulation tests were performed in laboratory by IR lamps using fiber cement specimens and in field by exposure solar radiation using prototypes with temperature monitoring. The results showed that the reflective paints present higher reflectivity and better thermal performance than the conventional paint, independently of the color. The results showed that the reflective paints present potential to reduce superficial temperature of fiber cement corrugated roofing sheets. It is necessary to continue the reflective colored paints study on durability and thermal performance by exposure tests.

Made available in DSpace on 2014-10-09T12:38:06Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:05:53Z (GMT). No. of bitstreams: 1 05639.pdf: 6476184 bytes, checksum: 3037d7c0ce96c51e46c15baa5bdd114c (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP / FAPESP:92/01672-4

Orientador: Ana Maria Falcão de Aragão Sadalla / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação / Made available in DSpace on 2018-08-11T10:07:58Z (GMT). No. of bitstreams: 1 Rausch_RitaBuzzi_D.pdf: 2048792 bytes, checksum: 0cb5708a6cb73d91ffc86a99604427e1 (MD5) Previous issue date: 2008 / Resumo: A formação inicial de professores no curso de Pedagogia da Universidade Regional de cBlumenau ¿ FURB ¿ tem a prática investigativa como abordagem metodológica do fazer docente, constituindo-se em espaço de constante aprendizagem e construção reflexiva do professor. Nesta perspectiva, incluiu, no currículo do curso, o Trabalho de Conclusão de Curso que possibilita a inserção do acadêmico à pesquisa científica. Neste contexto e a partir da indagação - como se constitui o processo de reflexividade do acadêmico/professor, em sua formação inicial, por meio da pesquisa do TCC - foi realizada esta pesquisa, cujo objetivo geral foi compreender o processo de reflexividade de acadêmicos de Pedagogia por meio da análise dos níveis de lógica reflexiva promovidos na realização do TCC. Participaram desta pesquisa sete acadêmicas cujos estudos foram orientados pela pesquisadora. Os momentos de orientação foram gravados e transcritos e a apresentação oral da pesquisa videogravada. Foi solicitado que cada acadêmica registrasse, também, em portfólios reflexivos, todo o processo vivenciado nessa atividade. Utilizamo-nos do software Qualiquantisoft para organizar os discursos orais e escritos das acadêmicas em expressões-chave e idéias centrais. Analisamos, após, os indicadores de níveis de lógica reflexiva e dos momentos de reflexão em cada etapa do desenvolvimento da pesquisa. Os níveis mais complexos de reflexividade aconteceram frente à necessidade de as alunas compreenderem a teoria e relacioná-la aos dados da pesquisa e nas situações de sucesso ou insucesso apresentadas por meio de meta-reflexões, e em sua maioria, registradas no portfólio. A orientadora exerceu um papel fundamental uma vez que a reflexividade é um processo evolutivo de aprendizagem e pode ser aprendido e o exercício da pesquisa promoveu uma ampliação nesse processo. Isto permite pensar que a pesquisa deve ser inserida e mantida nos currículos de formação inicial de professores, uma vez que ela contribui nos processos de desenvolvimento profissional e pessoal docentes, bem como na construção de conhecimento crítico acerca de suas práticas e ações atuais e prospectivas / Abstract: The initial teacher formation in the Pedagogy Course at Universidade Regional de Blumenau ¿ FURB university ¿ has an investigative practice as methodological approach for the teaching activity, being that a space for teacher¿s constant learning and reflective construction. Under such perspective, the End of Term Paper has been included in the course curriculum, which allows the learner¿s insertion in scientific research practice. In such context, this study has been developed, from the enquiry on how the learner/teacher¿s reflectivity process is constituted in their initial formation, by means of the end of term paper research. The general objective of this work is the comprehension of the reflectivity process presented by the academic learners from the Pedagogy course, through the analysis of the reflective logic level during the End of Term Paper development. Seven learners have taken part in this research, whose studies have been guided by the present researcher. The moments of orientation have been recorded and transcribed and the oral presentation video recorded. Each learner has been asked to register the complete process experienced during this activity in reflective portfolios. The software Qualiquantisoft has been used to organize the learners¿ speeches and written production according to key words and main ideas. After, we made the analysis of the indication of reflective logic levels and reflection moments in each stage of the research development. The most complex levels of reflectivity appeared facing the learners¿ needs to understand the theory and to relate it to the research data in the circumstances of success or failure, presented by means of meta-reflection, most of them registered in their portfolio. The researcher had an essential role since reflectivity is an evolutionary learning process that can be learned and the research activity provided the enhancement of such process. This fact allows the thought that research must be included and maintained in the curriculum of initial teacher formation courses, since it contributes with the process of teachers¿ professional and personal development, as well as with the construction of critical knowledge about the teachers¿ practice and their present and prospective actions / Doutorado / Ensino, Avaliação e Formação de Professores / Doutor em Educação

Using time-resolved photo-induced reflectivity, we reported for the first time a systematic work on the ultrafast response of Bi₂Sr₂CaCu₂O_8+δ (BSCCO-2212) and Tl₂Ba₂CuO_6+δ (TBCO-2201), measurements of detwinned YBa₂Cu₃O_7-δ (YBCO-123) single crystal with the electric field ̲E parallel to the a and b-axis and high-resolution measurements of the rising edge dynamics of YBCO-123 thin films. We identified similar photo-induced responses for BSCCO, TBCO and for YBCO with ̲E ⊥ ̲b, which indicates that we observed a universal response of HTSC coming from the CuO2 superconducting planes. This latter dynamics is composed of three different components corresponding to the superconducting, pseudogap and normal state. A bi-molecular model has been put forward to explain the linear temperature dependence of the decay rate; the model implies that the re-formation of the condensate is limited by the rate at which quasiparticle interact. Moreover, we observed superconducting fluctuations up to 13K above T_c and a divergence of the long-lived component magnitude at very low temperature, which is explained by a cw heating model. In the pseudogap state, we have several indications that the negative peak observed between T_c and T* has a different origin from that of the superconducting signal below T_c. We argued that the probe mechanism of the pseudogap signal is electronic excitations of the pseudogap correlations. In the normal state, the observed dynamics is similar to that of simple metals. In the second part of this thesis, the rising edge dynamics of YBCO has been resolved in time. The model developed to interpret the results implies that the hot quasiparticles relaxation time down to the Fermi energy is 55fs. In this context, we proved that the Mazin model cannot explain both the oscillatory and the non-oscillatory part of the dynamics in YBCO. Finally, in YBCO-123, a new response has been observed with ̲E ∥ ̲b. We argued that the origin of this component is intraband transitions. This dynamics is solely responsive to the pseudogap, coming from the difference in scattering rate between pre-formed pairs and quasiparticles in the Drude reflectivity. The response with ̲E ⊥ ̲b exhibits a strong a-b plane anisotropy in its long-lived component, which can be interpreted as a d-wave gap symmetry using the thermally-activated model.

La distribution des ions et des charges aux interfaces solide-liquide est d'une importance capitale dans de nombreux phénomènes et processus. En particulier, le développement de la microfluidique a renforcé la nécessité de comprendre et de contrôler les distributions d'ions dans la double couche électrique. En effet, les phénomènes qui se produisent dans la couche diffuse de Gouy-Chapman deviennent dominants dans la détermination des propriétés d'écoulement lorsque les tailles de canaux deviennent comparables à la longueur de Debye. Dans ce travail de thèse, nous avons utilisé la technique des ondes stationnaire de rayons X pour déterminer la distribution interfaciale d’ions. Nous avons développé des cellules de quelques centaines de nanomètres voir moins dont l’épaisseur est mesurée précisément par réflectivité des rayons X. Dans ces cellules, avons confiné le film liquide entre les multicouches qui permettent de créer l'onde stationnaire et un film polymère. La fluorescence des ions dans ce champ permet alors d’extraire leur distribution aux interfaces avec une résolution spatiale de quelques Angströms. Ce travail a été réalisé pour plusieurs solutions contenant différents mélanges d'ions monovalents (Chlorure, Potassium, Césium et Iode) à plusieurs concentrations. Dans une deuxième partie de ce travail, nous présentons les résultats pour des chlorures de lanthanides. Ces études nous ont permis de déterminer la composition de la couche de Stern et la distribution des ions au sein de cette couche pour l'ensemble des paires La3+/Ce3+, La3+/Eu3+, La3+/Gd3+, Ce3+/Eu3+, Ce3+/Gd3+ et Eu3+/Gd3+. Nous avons pu alors classer ces différents ions et discuter le classement. / The distribution of ions and charges at solid-water interfaces is of key importance in a number of phenomena and processes. In particular the development of microfluidics has strengthened the need for understanding and controlling ion distributions in the electric double layer. Indeed, phenomena occurring within the diffuse Gouy-Chapman layer become dominant in determining flow properties as channel size become on the same order of magnitude of the Debye length. In this thesis, we used the technique of X-ray standing waves to determine the distribution of interfacial ions. We have developed cells with thicknesses of a few hundred nanometers or less, precisely measured by X-ray reflectivity. The liquid film is confined between the multilayer which create the standing wave and a polymer film. The ion fluorescence allows to determine the interfacial distribution with a spatial resolution of a few Angstroms. This work was carried out for solutions containing different mixtures of monovalent ions (chloride, potassium, cesium and iodine) at several concentrations.In the second part of this work, we present the results for lanthanide chlorides. These studies have allowed us to determine the composition of the Stern layer and the distribution of ions in this layer for all pairs La3+/Ce3+, La3+/Eu3+, La3+/Gd3+, Ce3+/Eu3+, Ce3+/Gd3+ et Eu3+/Gd3+. We could then classify these ions and discuss the series.

This thesis focuses on the analysis of the external quantum efficiency of quantum dot-enhanced multi-junction solar cells. Divided in four major parts, it uses the experimental methodology developed in the SUNLAB. At first, a model is introduced to calculate the external quantum efficiency of single and multi-junction solar cells. This model takes into account the semiconductor physics governing the electrical property of the solar cell. It furthermore takes into account the optical transmission and reflection in the semiconductor structure using a transfer matrix method. The calculated curve fits a single junction GaAs solar cell's external quantum efficiency to a high degree of precision. Finally, an InGaP/GaAs/Ge solar cell's external quantum efficiency is calculated and it reproduces accurately the behavior of a measured cell. Second, the reflectivity of a solar cell is studied. An analysis technique involving using the fast Fourier transform of the oscillation in the reflectivity is introduced. This technique extracts the thicknesses of the top and middle subcells. The reflectivity is subsequently calculated using the transfer matrix method and it reproduces the behavior of the measured samples. Third, the effect of the addition of quantum dots in the middle subcell is studied. It is demonstrated that they extend the absorption range of the middle subcell. This is completed by first modeling the quantum mechanical behavior of the electrons and holes in the nanostructure. Their emission and absorption properties are derived. Those derived properties are verified by experimentally measured photoluminescence and electroluminescence of the nanostructures. The resulting model is then compared to experimentally measured external quantum efficiencies of single junction and multi-junction quantum dot-enhanced solar cells. Finally, a study of the bottom subcell artifact is completed. Using the fill-factor bias experiment, each of the contribution of the light coupling and the internal voltage biasing is decoupled. For the measured sample, an optimal voltage of 2.1 V is found to minimize the artifact. At this point, the internal voltage biasing creates an artifact of 1 % and the light coupling artifact is 8 %.