Browsing by Issue Date, starting with "1994"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- Investigation of the microstructure, chemical composition and lateral gorwth of TiN films deposited by laser-induced chemical vapour depositionPublication . Silvestre, António Jorge; Paramês, M. L. G. F.; Conde, OlindaA study of the laser direct writing of titanium nitride on mild steel substrates by pytolytic laser-induced chemical vapour deposition was carried out under different operating conditions. Lines of TiN were deposited from a reactive gas mixture of TiC1₄, N₂ and H₂ using a continuous wave TEM₀₀CO₂ laser beam as heat source. The deposited material was analysed by optical and scanning electron microscopies, wavelength-dispersive X-ray microanalysis and profilometry techniques. Golden coloured TiN films, close to the stoichiometric composition, were produced exhibiting good adherence, very fine grain size (~100nm) and broad gaussian, profiles. A time kinetics study based on the lateral growth rate of the deposited lines is also presented. From the transiente growth conditions, an empirical relation between the interaction time needed to achieve film deposition and the laser irradiance was established, which led to a value for the incubation period of 5.4 ns. This relation also gave a value for the threshold laser irradiance of 1.54 x 10ᶣ W cm-², in good agreement with the value found experimentally.
- O bacharelato em formação musical – Escola Superior de Música de LisboaPublication . Pinheiro, JoãoAo começar esta intervenção gostaria de agradecer à Direcção da APEM e à comissão organizadora deste seminário o convite que me foi feito enquanto responsável e coordenador do Bacharelato em Formação Musical da Escola Superior de Música de Lisboa a fim de vir aqui apresentar esta nova formação profissional de professores de Formação Musical, em funcionamento há já dois anos. Este convite confirma o lugar de destaque que este curso está já a ter no meio musical português, sendo o primeiro curso superior de formação de professores para o ensino específico da Música nas escolas vocacionais. Começarei por fazer uma breve análise do que, para mim, são os verdadeiros objectivos da Formação Musical e os seus conteúdos, fazendo seguidamente a descrição dos meios que pusemos ao dispor dos nossos alunos do curso de Formação Musical, apresentando a sua estrutura e organização assim como os seus conteúdos e suas orientações pedagógicas.
- Arte e modaPublication . Morais-Alexandre, PauloAnálise da moda no vestuário enquanto Arte, passível de análise estética respectivos critérios e ligação às artes plásticas. É ainda analisado, no âmbito desta problemática, a evolução do estatuto social do criador de Moda e a Moda na actualidade. ABSTRACT: The aim is the study of fashion in clothing as Art, the aesthetic criteria of its analysis and its connection with other arts. It is further analyzed, in the context of this problem, the evolution of status of fashions creators and Fashion today.
- The first normal stress difference and viscosity in shear of liquid crystalline solutions of hydroxypropylcellulose: new experimental data and theoryPublication . Fried, F.; Leal, Catarina R.; Godinho, M. H.; Martins, A. F.The constitutive equations for liquid crystalline polymers recently proposed by one of us [1] are applied here to interpret the behaviour of the shear viscosity η equation image and the first normal stress difference N1($ \dot \gamma $equation image) measured for liquid crystalline (LC) solutions of hydroxypropylcellulose in acetic acid. N1(equation image) is observed to change from positive to negative and again to positive, as the shear rate $ \dot \gamma $equation image increases, at lower concentrations, in the LC phase. The $ \dot \gamma $equation image-values at which N1 changes sign depend on the molecular mass (degree of polymerization) and on the concentration. η $ \dot \gamma $equation image shows a small Newtonian plateau at low shear rates and a strong shear-thinning at higher values of $ \dot \gamma $equation image. The rate of decrease of η $ \dot \gamma $equation image in this region shows an “hesitation” similar to one previously observed in LC solutions of poly-γ-benzyl-L-glutamate PBLG. All these observations can be rationalized within the frame-work of Martins' theory. The expressions for N1($ \dot \gamma $equation image) and η $ \dot \gamma $equation image derived from this theory fit very well (quantitatively) to the experimental data and some fundamental viscoelastic parameters of the system under study are thereby obtained for the first time.