20 Result(s)
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Article
M. F. Pereira
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Open AccessGiant controllable gigahertz to terahertz nonlinearities in superlattices
Optical nonlinearities are of perpetual importance, notably connected with emerging new materials. However, they are difficult to exploit in the gigahertz–terahertz (GHz–THz) range at room temperature and usin...
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Dose to the interventional radiologist in CTF-guided procedures
The aim of this work was to assess the occupational dose received by an interventional radiologist (IR) during computed tomography fluoroscopy (CTF)-guided procedures; to identify the most exposed areas of the...
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Luminescence and absorption in short period superlattices
This paper applies analytical approximations for the luminescence of short period semiconductor superlattices and analyses the low density regime, demonstrating that the theory clearly connects with low densit...
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S-type granite generation and emplacement during a regional switch from extensional to contractional deformation (Central Iberian Zone, Iberian autochthonous domain, Variscan Orogeny)
Zircon grains extracted from S-type granites of the Mêda-Escalhão-Penedono Massif (Central Iberian Zone, Variscan Orogen) constrain the timing of emplacement and provide information about potential magma sourc...
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Open AccessAutomated numerical characterization of dilute semiconductors per comparison with luminescence
This paper combines analytical approximations for the optical absorption and luminescence of semiconductors with trust region-reflective methods, delivering a robust numerical characterization method to be use...
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Provenance of upper Triassic sandstone, southwest Iberia (Alentejo and Algarve basins): tracing variability in the sources
Laser ablation ICP-MS U–Pb analyses have been conducted on detrital zircon of Upper Triassic sandstone from the Alentejo and Algarve basins in southwest Iberia. The predominance of Neoproterozoic, Devonian, Pa...
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Open AccessAnisotropy and nonlinearity in superlattices II
This paper uses the anisotropic medium approach to calculate nonlinear optical absorption in semiconductor superlattices. The study confirms that the nonlinearities increase with anisotropy suggesting that str...
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Open AccessAnisotropy and nonlinearity in superlattices
This paper uses analytical expressions for the nonlinear optical absorption of superlattices by treating them as anisotropic media. The controllable system shows that the nonlinearities increase with anisotrop...
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The multistage crystallization of zircon in calc-alkaline granitoids: U–Pb age constraints on the timing of Variscan tectonic activity in SW Iberia
CL imaging and U–Th–Pb data for a population of zircons from two of the Évora Massif granitoids (Ossa-Morena Zone, SW Iberia) show that both calc-alkaline granitoids have zircon populations dominated by grain...
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Simulations of mid infrared emission of InAsN semiconductors
This paper delivers an approximation to the complex many body problem of luminescence in semiconductors to the case of mid infrared luminescence of dilute nitrides. The results are compared with recent experim...
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TERA-MIR radiation: materials, generation, detection and applications II
The main objective of MPNS COST ACTION MP1204 is to advance novel materials, concepts and device designs for generating and detecting THz (0.3–10 THz) and Mid Infrared (10–100 THz) radiation using semiconducto...
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Implementation of the quality management system at the Laboratory of Radiological Protection and Safety (LPSR) in Portugal
The paper describes the activities carried out for the implementation of the quality management system (QMS) at the Laboratory of Radiological Protection and Safety (LPSR) in Portugal in order to achieve the m...
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Variability over time in the sources of South Portuguese Zone turbidites: evidence of denudation of different crustal blocks during the assembly of Pangaea
This study combines geochemical and geochronological data in order to decipher the provenance of Carboniferous turbidites from the South Portuguese Zone (SW Iberia). Major and trace elements of 25 samples of g...
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Early Cambrian granitoids of North Gondwana margin in the transition from a convergent setting to intra-continental rifting (Ossa-Morena Zone, SW Iberia)
Two distinct Cambrian magmatic pulses are recognized in the Ossa-Morena Zone (SW Iberia): an early rift-(ER) and a main rift-related event. This Cambrian magmatism is related to intra-continental rifting of No...
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TERA-MIR radiation: materials, generation, detection and applications
This special edition is dedicated to original papers covering topics with the areas of interest of COST ACTION MP1204 whose main objective is to advance novel materials, concepts and device designs for generat...
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Interaction of valence band excitations and terahertz TE-polarized cavity modes
The strong coupling of THz radiation and material excitations has potential to improve the quantum efficiency of THz devices. In this paper, we investigate a simple structure delivering THz polaritons and anti...
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Many body theory of THz intervalence gain in quantum wells
This paper presents calculations of THz gain in III–V quantum wells based on transitions between the valence bands. The system is out of equilibrium and the optical susceptibility leading to absorption and gai...
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Intersubband vs interband-light coupling in semiconductors
This paper presents a direct comparison and contrast of strong light coupling with either interband or intersubband excitations in semiconductors. The approach is based on analytical expressions obtained after...
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Transcurrent continental tectonics model for the Ossa-Morena Zone Neoproterozoic–Paleozoic evolution, SW Iberian Massif, Portugal
The Ossa-Morena Zone (SW Iberian Massif) was affected by continuous orogen-parallel transcurrent continental tectonics from the Neoproterozoic to the Carboniferous times, involving transtension (TT) and transp...
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The Amino Acid Sequence of Bothropstoxin-II, an Asp-49 Myotoxin from Bothrops jararacussu (Jararacucu) Venom with Low Phospholipase A2 Activity
The complete amino acid sequence of bothropstoxin-II (BthTX-II), a myotoxin isolated from Bothrops jararacussu snake venom, is reported. The results show that BthTX-II is an Asp-49 phospholipase A2 (PLA2)-like pr...
