Institution
University of Coimbra
Education•Coimbra, Portugal•
About: University of Coimbra is a education organization based out in Coimbra, Portugal. It is known for research contribution in the topics: Population & Context (language use). The organization has 14318 authors who have published 43067 publications receiving 994733 citations. The organization is also known as: UC & Universidade dos Estudos Gerais.
Papers published on a yearly basis
Papers
More filters
••
TL;DR: The fluorescence quantum yield of N-phenyl-1-naphthylamine (NPN) increases about 10-fold and the wavelength of maximum fluorescence emission is blue-shifted when this molecule partitions into the apolar core of micellar structures from the aqueous phase, which allowed the utilization of NPN as a fluorescent indicator of micelle formation by 14 different surfactants belonging to the families of alkyltrimethylammonium halides.
186 citations
••
TL;DR: In this paper, a two-phase system composed of a nanocrystalline f.c. structure was synthesized by RF reactive sputtering from Ti and Si elemental targets, in an Ar/N 2 gas mixture.
Abstract: Ti 1− x Si x N y films were synthesised by RF reactive sputtering from Ti and Si elemental targets, in an Ar/N 2 gas mixture. XRD results revealed the development of a two-phase system, composed of a nanocrystalline f.c.c. TiN (phase 1: B1 NaCl type) and a second one (phase 2), where Si atoms replaced some of the Ti ones, inducing a structure that we may call a solid solution. An amorphous phase, supposed to be of silicon nitride, within grain boundaries seems to be also present, especially for high Si contents. TEM experiments confirmed the f.c.c.-type structure for phase 2, which is the only phase that develops without ion bombardment. The higher lattice parameter of phase 1 (∼0.429 nm compared to 0.424 nm for bulk TiN) may be explained by the residual stress effect on peak position. The Ti replacement by Si would explain the low value of the lattice parameter for phase 2 (∼0.418 nm). All samples showed good results for hardness (Hv≥30 GPa), and Ti 0.85 Si 0.15 N 1.03 at a deposition temperature of 300°C showed a value of approximately 47 Gpa, which is approximately double that of pure TiN. For higher deposition temperatures, an increase in hardness is observed, as demonstrated by this same sample, which at 400°C reveals a value of approximately 54 GPa. Similar behaviour was observed in adhesion, where this same sample revealed a critical load for adhesive failure of approximately 90 N. In terms of oxidation resistance, a significant increase has also been observed in comparison with TiN. At 600°C, the oxidation resistance of Ti 0.70 Si 0.30 N 1.10 is already 100 times higher than that of TiN. For higher temperatures this behaviour tends to be even better when compared with other nitrides.
186 citations
••
Alfred Wegener Institute for Polar and Marine Research1, Victoria University of Wellington2, Natural Environment Research Council3, Goddard Space Flight Center4, Scott Polar Research Institute5, Spanish National Research Council6, Instituto Antártico Argentino7, University of Hawaii at Manoa8, IFREMER9, University of Coimbra10
TL;DR: Assessment of observed and projected environmental changes in the Southern Ocean shows that aragonite undersaturation (acidification) might become one of the biggest problems for the Antarctic marine ecosystem by affecting almost the entire SO.
Abstract: A quantitative assessment of observed and projected environmental changes in the Southern Ocean (SO) with a potential impact on the marine ecosystem shows: (i) large proportions of the SO are and will be affected by one or more climate change processes; areas projected to be affected in the future are larger than areas that are already under environmental stress, (ii) areas affected by changes in sea-ice in the past and likely in the future are much larger than areas affected by ocean warming. The smallest areas (<1% area of the SO) are affected by glacier retreat and warming in the deeper euphotic layer. In the future, decrease in the sea-ice is expected to be widespread. Changes in iceberg impact resulting from further collapse of ice-shelves can potentially affect large parts of shelf and ephemerally in the off-shore regions. However, aragonite undersaturation (acidification) might become one of the biggest problems for the Antarctic marine ecosystem by affecting almost the entire SO. Direct and indirect impacts of various environmental changes to the three major habitats, sea-ice, pelagic and benthos and their biota are complex. The areas affected by environmental stressors range from 33% of the SO for a single stressor, 11% for two and 2% for three, to <1% for four and five overlapping factors. In the future, areas expected to be affected by 2 and 3 overlapping factors are equally large, including potential iceberg changes, and together cover almost 86% of the SO ecosystem.
186 citations
••
TL;DR: In this article, the authors describe a model-agnostic search for pairs of jets (dijets) produced by resonant and non-resonant phenomena beyond the Standard Model.
185 citations
••
TL;DR: The X-ray Imaging Polarimetry Explorer (XIPE) as discussed by the authors is a mission dedicated to Xray Astronomy which is in a competitive phase A as fourth medium size mission of ESA (M4).
Abstract: XIPE, the X-ray Imaging Polarimetry Explorer, is a mission dedicated to X-ray Astronomy. At the time of writing XIPE is in a competitive phase A as fourth medium size mission of ESA (M4). It promises to reopen the polarimetry window in high energy Astrophysics after more than 4 decades thanks to a detector that efficiently exploits the photoelectric effect and to X-ray optics with large effective area. XIPE uniqueness is time-spectrally-spatially- resolved X-ray polarimetry as a breakthrough in high energy astrophysics and fundamental physics. Indeed the payload consists of three Gas Pixel Detectors at the focus of three X-ray optics with a total effective area larger than one XMM mirror but with a low weight. The payload is compatible with the fairing of the Vega launcher. XIPE is designed as an observatory for X-ray astronomers with 75 % of the time dedicated to a Guest Observer competitive program and it is organized as a consortium across Europe with main contributions from Italy, Germany, Spain, United Kingdom, Poland, Sweden.
185 citations
Authors
Showing all 14693 results
Name | H-index | Papers | Citations |
---|---|---|---|
P. Chang | 170 | 2154 | 151783 |
Yang Gao | 168 | 2047 | 146301 |
Bin Liu | 138 | 2181 | 87085 |
P. Sinervo | 138 | 1516 | 99215 |
Filipe Veloso | 128 | 887 | 75496 |
Panagiotis Kokkas | 128 | 1234 | 81051 |
Nuno Filipe Castro | 128 | 960 | 76945 |
Robert Gardner | 128 | 1015 | 77619 |
Francois Corriveau | 128 | 1022 | 75729 |
Peter Krieger | 128 | 1171 | 81368 |
João Carvalho | 126 | 1278 | 77017 |
Helmut Wolters | 126 | 851 | 75721 |
Nicola Venturi | 126 | 796 | 69518 |
Sai-Juan Chen | 121 | 1211 | 73991 |
Harinder Singh Bawa | 120 | 798 | 66120 |