Thesis (doctoral)--Karolinska Institutet, Stockholm, 1984. / Extra t.p. with thesis statement inserted. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 34-42).

Thesis (doctoral)--Karolinska Institutet, Stockholm, 1984. / Extra t.p. with thesis statement inserted. Includes bibliographical references (p. 34-42).

III-nitride optoelectronic devices have become ubiquitous due to their ability to emit light efficiently in the blue and green spectral ranges. Specifically, III-nitride light emitting diodes (LEDs) have become widespread due to their high brightness and efficiency. However, III-nitride devices such as single photon sources are also the subject of research and are promising for various applications. In order to improve design efficient devices and improve current ones, the relationship between the structure of the constituent materials and their optical properties must be studied. The optical properties of materials are often examined by photoluminescence or cathodoluminescence, whilst traditional microscopy techniques such a transmission electron microscopy and scanning electron microscopy are used to elucidate their structure and composition. This thesis describes the use of a dual-beam focussed ion beam/scanning electron microscope (FIB/SEM) in bridging the gap between these two types of techniques and providing a platform on which to perform correlative studies between the optical and structural properties of III-nitride materials. The heteroepitaxial growth of III-nitrides has been known to produce high defect densities, which can harm device performance. We used this correlative approach to identify hexagonal defects as the source of inhomogeneous electroluminescence (EL) in LEDs. Hyperspectral EL mapping was used to show the local changes in the emission induced by the defects. Following this the FIB/SEM was used to prepare TEM samples from the apex of the defects, revealing the presence of p-doped material in the active region caused by the defect. APSYS simulations confirmed that the presence of p-doped material can enhance local EL. The deleterious effects of defects on the photoelectrochemical etching of cavities were also studied. We performed TEM analysis of an edge-defect contained in unetched material on the underside of a microdisk using FIB/SEM sample preparation methods. The roughness and morphology of microdisk and nanobeam cavities was studied using FIB-tomography (FIBT), demonstrating how the dual-beam instrument may be used to access the 3D morphology of cavities down to the resolution of the SEM and the slicing thickness of the FIB. This tomography approach was further extended with electron tomography studies of the nanobeam cavities, a technique which provided fewer issues in terms of image series alignment but also the presence of reconstruction artefacts which must be taken into account when quantitatively analysing the data. The use of correlative techniques was also used to establish the link between high Si content in an interlayer running along the length of microrods with changes in the optical emission of these rods. The combination of CL, FIB/SEM and TEM-based techniques has made it possible to gain a thorough understanding of the link between the structural and optical properties in a wide variety of III-nitride materials and devices.

Orientador: Márcio Zaffalon Casati / Dissertação (mestrado) - Universidade Estadual de Campinas. Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-16T08:30:39Z (GMT). No. of bitstreams: 1 Pieri_AlexandraPaula_M.pdf: 2282598 bytes, checksum: 7fecd7736954b300b66152ae7095fe29 (MD5) Previous issue date: 2010 / Resumo: A topografia da superfície radicular é um fator importante para a manutenção da saúde dos tecidos periodontais, e a raspagem para remoção de biofilme promove alterações nessa superfície. O objetivo do presente estudo foi avaliar, por meio da análise rugosimétrica e em microscopia eletrônica de varredura, a rugosidade radicular provocada pela instrumentação periodontal com aparelho ultra-sônico piezoelétrico, utilizando diferentes substâncias irrigadoras, e comparar com o uso de cureta e de ultrassom magnetoestritivo. Para isso, foram selecionados 60 pré-molares humanos extraídos por motivos ortodônticos, que foram lavados em água corrente e acondicionados em recipientes com formol a 10%. Os dentes foram divididos aleatoriamente em 06 grupos experimentais (n=10 cada): Grupo 01: grupo controle, sem instrumentação; Gupo 02: instrumentados com curetas Gracey 5/6; Gupo 03: com aparelho ultra-sônico magnetoestritivo; Gupo 04: com aparelho ultra-sônico piezoelétrico associado ao fluido abrasivo; Grupo 05: com aparelho ultra-sônico piezoelétrico associado ao fluido polidor; Grupo 06: com aparelho ultra-sônico piezoelétrico associado aos fluidos abrasivo e polidor na seqüência. Após o tratamento das superfícies, foram realizadas, com Rugosímetro, três leituras paralelas e três perpendiculares ao sentido da raspagem para determinar os índices Ra e Rz de Rugosidade Superficial Média. Além disso, foram realizadas leituras com aumento de 50 e 250 vezes em Microscopia Eletrônica de Varredura (MEV). Para a avaliação estatística foi utilizada análise de variância (ANOVA) e teste Tukey, com nível de significância de 5%. Foi observado aumento da rugosidade independentemente do instrumento utilizado, ao comparar as superfícies tratadas com as do grupo controle (p<0,05). A instrumentação com o sistema piezoelétrico associado ao fluido polidor proporcionou as superfícies menos rugosas; o ultrassom magnetoestritivo produziu a maior rugosidade superficial entre os grupos estudados (p<0,05). Dentre os grupos do sistema piezoelétrico, o que utilizou o fluido abrasivo proporcionou os valores mais altos de rugosidade. O uso associado dos fluidos abrasivo e polidor foi semelhante ao uso da cureta, e produziu superfícies com rugosidade significativamente maior que a do uso do piezoelétrico com fluido polidor. Portanto, diante dos resultados obtidos, pode-se concluir que o uso das diferentes substâncias irrigadoras na instrumentação com ultrassom piezoelétrico influencia na rugosidade radicular. O fluido abrasivo incrementa a rugosidade superficial, mas ainda assim, o aparelho magnetoestritivo deixa as superfícies mais rugosas. A técnica que utilizou o ultrassom piezoelétrico com fluido polidor foi a que resultou nas superfícies menos rugosas / Abstract: The topography of the root surface is an important factor for maintaining periodontal tissues healthy, and scaling for biofilm removal promotes alterations in that surface. The aim of this study was to evaluate with rugosimeter and SEM examination, root roughness after instrumentation with a piezoelectric ultrasonic device using different irrigation substances, comparing with curettes and magnetostrictive ultrasonic device. Sixty human pre-molars that had been extracted for orthodontic reasons were washed in running water and kept in 10% formaldehyde until the experiment was carried. The teeth were randomly divided into 6 experimental groups (n=10, each): Group 01: control group, no instrumentation; Group 02: instrumentation with Gracey 5/6curettes; Group 03: instrumentation with a magnetostrictive ultrasonic device, Group 04: piezoelectric ultrasonic device associated to abrasive fluid, Group 05: piezoelectric ultrasonic device associated to polishing fluid, and Group 06: piezoelectric ultrasonic device associated to abrasive fluid followed by polishing fluid. After root surface treatments, three readings were carried with a rugosimeter, both parallel and perpendicularly to the direction of the scaling, in order to determine Ra and Rz rates of average surface roughness. In addition, readings with 50x and 250x magnification on Scanning Electron Microscope (SEM) were done. For statistical analysis, ANOVA and Tukey's test were used, with significance level at 5%. An increase in roughness was observed, regardless of the instrument used, when comparing treated surfaces to those in control group (p<0,05). Instrumentation with piezoelectric system associated to polishing fluid provided less rough surfaces; magnetostrictive device caused the highest roughness among the studied groups (p<0.05). Among the groups using piezoelectric system, the one using abrasive fluid caused the highest values in roughness. The combined use of abrasive and polishing fluids subsequently was similar to the curette, and produced surfaces with roughness significantly higher than piezoelectric system with polishing fluid. With the obtained results, it can be concluded that the use of different irrigation substances during instrumentation with piezoelectric ultrasonic device can influence on root surface roughness. The abrasive fluid increments surface roughness, but the magnetostrictive device is still less aggressive that. The technique that used piezoelectric ultrasound with polishing fluid resulted in less rough surfaces / Mestrado / Periodontia / Mestre em Clínica Odontológica

Orientador: Regina Maria Puppin-Rontani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-20T03:04:08Z (GMT). No. of bitstreams: 1 Benetello_Vanessa_M.pdf: 1255246 bytes, checksum: 803f9952085605139f802d3ac1bca050 (MD5) Previous issue date: 2012 / Resumo: O objetivo neste estudo foi avaliar o efeito de diferentes pastas obturadoras e agentes de limpeza sobre a dentina radicular de dentes decíduos, sobre: a estrutura molecular; e a morfologia de superfície da dentina radicular em dentes decíduos. Foram utilizadas 80 raízes de dentes decíduos anteriores extraídos por razões clínicas. As coroas foram seccionadas na junção cemento-esmalte e descartadas; e as raízes seccionadas no sentido longitudinal expondo os condutos radiculares, as quais foram planificadas e sonicadas. As raízes foram fixadas com resina composta para facilitar o manuseio, em seguida os condutos foram instrumentados com limas tipo K (15 a 35) e irrigados a cada troca de lima com hipoclorito de sódio a 0,5% + EndoPTC. Então, os espécimes foram distribuídos em 4 grupos de acordo com as pastas obturadoras (n=20): Controle-CP (sem obturação), Calen® espessada com óxido de zinco-CZ, Calcipex II®-CII, Vitapex®-V. Após a obturação, os espécimes foram armazenamentos por 7 dias. Após esse período, as pastas obturadoras foram removidas e os espécimes foram subdivididos em 4 grupos de acordo com os agentes de limpeza (n=5): Controle-CL (Sem limpeza), Etanol-E, Tergenform®-T, Ácido fosfórico-AF 35%...Observação: O resumo, na íntegra, poderá ser visualizado no texto completo da tese digital / Abstract: The aim of this study was to verify the effect the different filling pastes and cleaning agents in primary dentin root, as: molecular structure and morphologic structure the surface of root dentin in primary teeth. For the study were used 80 anterior primary teeth roots extracted for clinical reasons. The crowns of the teeth were sectioned at cement enamel junction and discarded. The roots were separated longitudinally exposing the root canal, which were ground flat and sonicated. The specimens were fixed using composite resin to facilitate manipulation, and then they were prepared with K-type files size #15-35 and irrigated with of 0.5% sodium hypochlorite solution + EndoPTC cream. Thus, were divided into 4 groups (n=20) according to the filling pastes: Control (without filling), Calen® paste thickened with zinc oxide, Calcipex II®, Vitapex®. Then, the specimens were stored for seven days. After that, filling paste was removed and the specimens were subdivided into 4 cleaning agents groups (n=5): Control (without cleaning agents), Ethanol, Tergenform®, Phosphoric acid (35%)...Note: The complete abstract is available with the full electronic document / Mestrado / Odontopediatria / Mestre em Odontologia

by Chung-fai Kwok. / Thesis (M.Sc.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 65). / Contents --- p.i / Table of Figures --- p.iii / Abstract --- p.v / Acknowledgment --- p.vii / Introduction --- p.viii / Chapter 1. --- Overview : Medical image network system --- p.1 / Chapter 1.1 --- MAGNET --- p.1 / Chapter 1.2 --- Medical image --- p.2 / Chapter 2. --- System configuration --- p.4 / Chapter 2.1 --- Hardware setting --- p.4 / Chapter 2.2 --- Software functions design --- p.5 / Chapter 3. --- Color handling --- p.7 / Chapter 3.1 --- Color --- p.7 / Chapter 3.2 --- Colormap and color display --- p.9 / Chapter 3.3 --- Static and dynamic color mapping --- p.10 / Chapter 4. --- Color image processing --- p.11 / Chapter 4.1 --- Color image quantization --- p.11 / Chapter 4.1.1 --- Pre-quantization --- p.13 / Chapter 4.1.2 --- Median cut Algorithm --- p.15 / Chapter 4.1.3 --- Remapping colors --- p.16 / Chapter 4.1.4 --- Hashing --- p.17 / Chapter 4.1.5 --- Distortion Measures --- p.21 / Chapter 4.1.6 --- Experiment results and Discussion --- p.22 / Chapter 4.2 --- Intensity mapping --- p.30 / Chapter 4.2.1 --- Graylevel image contrast enhancement and reduction --- p.30 / Chapter 4.2.2 --- Graylevel image brightness increment and reduction --- p.36 / Chapter 4.2.3 --- Contrast enhancement and reduction on color components --- p.40 / Chapter 4.2.4 --- Brightness increment and reduction on color components --- p.41 / Chapter 4.3 --- Pseudocoloring --- p.45 / Chapter 5. --- Color image analysis --- p.47 / Chapter 5.1 --- Region Measures --- p.47 / Chapter 5.1.1 --- Region measures function design --- p.47 / Chapter 5.1.2 --- Region growing mechanism --- p.48 / Chapter 5.1.3 --- Region smoothing --- p.49 / Chapter 5.2 --- Distance measures --- p.53 / Chapter 5.3 --- Statistical analysis --- p.53 / Chapter 6. --- Summary and future work --- p.57 / Appendix : User interfaces and functions --- p.58 / Bibliography --- p.65

Thesis (M.S.)--Rochester Institute of Technology, 1991. / Spine title: Application of morphological pseudoconvolutions to STM images. Includes bibliographical references.

Thesis (Ph. D.)--University of Washington, 1998. / Vita. Includes bibliographical references (leaves [140]-152).

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 290-319).

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.