Num contexto histórico, a frequência de gestações trigemelares atingiu o seu auge nos finais do século XX e diminuiu significativamente a partir de então, registando-se atualmente uma frequência de 0,2 por 1000 grávidas. Atualmente, os grandes fatores etiológicos que estão na or…
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A fabricação digital se tornou uma realidade para a produção em diversos setores da indústria nos últimos anos. Com seu uso desenvolvido e consolidado em alguns setores como a medicina, a arquitetura e a robótica, ela ainda é pouco explorada na moda apresentando um grande potenc…
The parameter space over which electron beams operate for pumping CO₂ lasers significantly extended. A repetitive pulsed power/electron beam system for the generation of 45 µs, 220 keV, electron beams for CO₂ lasers has been designed and implemented which can operate over a 6:1 …
Lasers find a wide range of applications in many areas including photo-biology, photo-chemistry, materials processing, imaging and telecommunications. However, the practical use of such sources is often limited by the bulky nature of existing systems. By fabricating channel wave…
In recent years, interest has grown in the research fields of semiconductor lasers and photonic crystals. This thesis looks at integrating photonic crystals into existing semiconductor laser technology to act as functional laser mirrors. The majority of the research is conducted…
This thesis presents an investigation of the lasing dynamics and optical amplification devices using conjugated polymers. Spectroscopic studies of conjugated polymers and dendrimers were also performed. Conjugated polymers and dendrimers are materials with great potential as dis…
In this Dissertation our work on `enhanced thermally managed packaging of high power semiconductor light sources for solid state lighting (SSL)' is presented. The motivation of this research and development is to design thermally high stable cost-efficient packaging of single an…
The objective of this thesis is to report on the design and fabrication of a claddingpumped rare-earth-doped ZBLAN fiber laser in a free-space linear cavity. The double-clad structure with high numerical aperture allows for efficient pumping of the gain medium. The influence of …
Fueled in part by recent applications in neuroscience, high-dimensional Hawkes processes are widely used for modeling the network of interactions among multivariate point processes. Despite this popularity, existing methodological and theoretical work has mainly focused on estim…
The Earth is rotating around its rotation axis in an irregular manner. The Earth rotation axis and its orientation in space vary with respect to the reference system (both the terrestrial and the celestial) due to the wide range of processes that contribute to the rotation excit…
The ability to recognize molecular processes using novel imaging techniques is crucial for medicine, biology and biochemistry. A widely used technique is magnetic resonance imaging (MRI). The signal to noise ratio of the measured data is proportional to the polarization of a giv…
Spin-based electronics seek to utilize the properties of electron spin in order to develop next-generation devices with novel functionalities and applications. As with conventional electronics, semiconductors play a critical role in spintronics by allowing for the active manipul…
Os tumores carcinóides broncopulmonares representam um tumor maligno e raro do pulmão. Esta neoplasia deriva de células neuroendócrinas, o que lhe confere a capacidade de secretar hormonas e substâncias bioativas, no entanto, as síndromes paraneoplásicas representam apenas uma p…
A constante evolução industrial e a alta dependência das empresas nos seus equipamentos industriais, faz com que seja essencial garantir o desempenho destes, quando expostos a determinadas condições. Neste contexto, a manutenção industrial tem um contributo significativo para al…