20 resultados para Preparation of substrate
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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau de Mestre em Mestrado Integrado em Engenharia Química e Bioquímica
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Dissertation to obtain the Master Degree in Biotechnology
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Shape Memory Alloy (SMA) Ni-Ti films have attracted much interest as functional and smart materials due to their unique properties. However, there are still important issues unresolved like formation of film texture and its control as well as substrate effects. Thus, the main challenge is not only the control of the microstructure, including stoichiometry and precipitates, but also the identification and control of the preferential orientation since it is a crucial factor in determining the shape memory behaviour. The aim of this PhD thesis is to study the optimisation of the deposition conditions of films of Ni-Ti in order to obtain the material fully crystallized at the end of the deposition, and to establish a clear relationship between the substrates and texture development. In order to achieve this objective, a two-magnetron sputter deposition chamber has been used allowing to heat and to apply a bias voltage to the substrate. It can be mounted into the six-circle diffractometer of the Rossendorf Beamline (ROBL) at the European Synchrotron Radiation Facility (ESRF), Grenoble, France, enabling an in-situ characterization by X-ray diffraction(XRD) of the films during their growth and annealing. The in-situ studies enable us to identify the different steps of the structural evolution during deposition with a set of parameters as well as to evaluate the effect of changing parameters on the structural characteristics of the deposited film. Besides the in-situ studies, other complementary ex-situ characterization techniques such as XRD at a laboratory source, Rutherford backscattering spectroscopy(RBS), Auger electron spectroscopy (AES), cross-sectional transmission electron microscopy (X-TEM), scanning electron microscopy (SEM), and electrical resistivity (ER) measurements during temperature cycling have been used for a fine structural characterization. In this study, mainly naturally and thermally oxidized Si(100) substrates, TiN buffer layers with different thicknesses (i.e. the TiN topmost layer crystallographic orientation is thickness dependent) and MgO(100) single crystals were used as substrates. The chosen experimental procedure led to a controlled composition and preferential orientation of the films. The type of substrate plays an important role for the texture of the sputtered Ni-Ti films and according to the ER results, the distinct crystallographic orientations of the Ni-Ti films influence their phase transformation characteristics.
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Dissertação apresentada para a obtenção do grau de Doutor em Engenharia Química, especialidade Engenharia da Reacção Química, pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia
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Dissertation presented at the Faculty of Sciences and Technology of the New University of Lisbon in fulfillment of the requirements for the Master degree in Conservation Science
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Mestrado integrado em Engenharia Química e Bioquímica
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FEBS journal, Volume 278, Issue 14, pages 2511-2524, July 2011
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Dissertação para obtenção do Grau de Mestre em Engenharia Geológica (Georrecursos)
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Dissertação para obtenção do Grau de Doutor em Bioengenharia (MIT)
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Dissertation to obtain the degree of master in Bioorganic
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J Biol Inorg Chem (2011) 16:51–61 DOI 10.1007/s00775-010-0700-8
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J Biol Inorg Chem (2010) 15:967–976 DOI 10.1007/s00775-010-0658-6
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Dissertação para obtenção do Grau de Mestre em Biotecnologia
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Dissertation presented to obtain the Ph.D degree in Biochemistry, Structural Biochemistry
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Dissertação para obtenção do Grau de Mestre em Engenharia Química e Bioquímica