| 1. |
- Wagner, J., et al.
(författare)
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First 230? : GHz VLBI fringes on 3C 279 using the APEX Telescope (Research Note)
- 2015
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 581
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Tidskriftsartikel (refereegranskat)abstract
- Aims. We report about a 230? GHz very long baseline interferometry (VLBI) fringe finder observation of blazar 3C 279 with the APEX telescope in Chile, the phased submillimeter array (SMA), and the SMT of the Arizona Radio Observatory (ARO). Methods. We installed VLBI equipment and measured the APEX station position to 1? cm accuracy (1σ). We then observed 3C 279 on 2012 May 7 in a 5? h 230? GHz VLBI track with baseline lengths of 2800? Mλ to 7200? Mλ and a finest fringe spacing of 28.6? μas. Results. Fringes were detected on all baselines with signal-to-noise ratios of 12 to 55 in 420? s. The correlated flux density on the longest baseline was ∼0.3? Jy beam-1, out of a total flux density of 19.8? Jy. Visibility data suggest an emission region ≤ 38? μas in size, and at least two components, possibly polarized. We find a lower limit of the brightness temperature of the inner jet region of about 1010? K. Lastly, we find an upper limit of 20% on the linear polarization fraction at a fringe spacing of ∼ 38? μas. Conclusions. With APEX the angular resolution of 230? GHz VLBI improves to 28.6? μas. This allows one to resolve the last-photon ring around the Galactic Center black hole event horizon, expected to be 40? μas in diameter, and probe radio jet launching at unprecedented resolution, down to a few gravitational radii in galaxies like M 87. To probe the structure in the inner parsecs of 3C 279 in detail, follow-up observations with APEX and five other mm-VLBI stations have been conducted (March 2013) and are being analyzed.
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| 2. |
- Mikhaylov, Aleksey I., et al.
(författare)
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On the ion implantation of phosphorus as a method for the passivation of states at the interface between 4H-SiC and SiO2 produced by thermal oxidation in dry oxygen
- 2014
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Ingår i: Semiconductors (Woodbury, N.Y.). - : Maik Nauka-Interperiodica Publishing. - 1063-7826 .- 1090-6479. ; 48:12, s. 1581-1585
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Tidskriftsartikel (refereegranskat)abstract
- A method is suggested for reducing the density of surface states at the 4H-SiC/SiO2 interface by the implantation of phosphorus ions into a 4H-SiC epitaxial layer immediately before the growth of a gate insulator in an atmosphere of dry oxygen. A significant decrease in the density of surface states is observed at a phosphor-ion concentration at the SiO2/SiC interface exceeding 1018 cm−3. However, together with the passivation of surface states, the introduction of phosphorus ions leads to an increase in the built-in charge in the insulator and also slightly deteriorates the reliability of the gate insulator fabricated by this technique.
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| 3. |
- Saxholm, S., et al.
(författare)
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Development of measurement and calibration techniques for dynamic pressures and temperatures (DynPT) : Background and objectives of the 17IND07 DynPT project in the European Metrology Programme for Innovation and Research (EMPIR)
- 2018
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Ingår i: Journal of Physics. - : Institute of Physics Publishing.
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Konferensbidrag (refereegranskat)abstract
- This project has five specific objectives: To provide traceability for dynamic pressure and temperature through development of measurement standards and validated calibration procedures; To quantify the effects of influencing quantities on the response of dynamic pressure and temperature sensors, in order to determine the appropriate calibration procedures and measurement uncertainties for industrial measurements; To develop new measurement methods and sensors for measuring dynamic pressure and temperature in demanding industrial applications, and to demonstrate the improved accuracy and reliability obtained with those; To validate all of the methods and sensors developed in this project through demonstrations in selected industrial applications; and To ensure by close engagement with industry, that the developed calibration and measurement techniques and technology are adopted by them. The challenge is that in many industrial applications pressure and temperature measurements are performed under dynamically changing conditions. The aim of this project is to improve the accuracy and reliability of pressure and temperature measurements in these challenging conditions. A European joint research project named Development of measurement and calibration techniques for dynamic pressures and temperatures (shortname DynPT) started in the summer 2018.
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| 4. |
- Merlone, Andrea, et al.
(författare)
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A new challenge for meteorological measurements : The meteoMet project-Metrology for meteorology
- 2013
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Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X .- 1551-7616. - 9780735411784 ; , s. 1030-1035
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Konferensbidrag (refereegranskat)abstract
- Climate change and its consequences require immediate actions in order to safeguard the environment and economy in Europe and in the rest of world. Aiming to enhance data reliability and reduce uncertainties in climate observations, a joint research project called MeteoMet-Metrology for Meteorology started in October 2011 coordinated by the Italian Istituto Nazionale di Ricerca Metrologica (INRiM). The project is focused on the traceability of measurements involved in climate change: surface and upper air measurements of temperature, pressure, humidity, wind speed and direction, solar irradiance and reciprocal influences between measurands. This project will provide the first definition at the European level of validated climate parameters with associated uncertainty budgets and novel criteria for interpretation of historical data series. The big challenge is the propagation of a metrological measurement perspective to meteorological observations. When such an approach will be adopted the requirement of reliable data and robust datasets over wide scales and long terms could be better met.
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| 5. |
- Quignon, Benoit, et al.
(författare)
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Sustained Frictional Instabilities on Nanodomed Surfaces : Stick Slip Amplitude Coefficient
- 2013
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Ingår i: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 7:12, s. 10850-10862
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Tidskriftsartikel (refereegranskat)abstract
- Understanding the frictional properties of nanostructured surfaces is important because of their increasing application in modem minlaturized devices. In this work, lateral force microscopy was used to study the frictional properties between AFM nanotip and surfaces bearing well-defined ranging from tens to hundreds of nanometers. Our results show that the average lateral force varied linearly with applied load, as described by Amontons' first law of friction, although no direct correlation between the sample topographic properties and their measured friction coeffidents was identified. Furthermore, all the nanodomed textures exhibited pronounced osdllations in the shear traces, similar to the dassic stick slip behavior, under all the shear velocities and load regimes studied. That is, the nanotextured topography led to sustained frictional instabilities, effectively with no contact frictional sliding. The amplitude of the stick slip oscillations, ab was found to correlate with the topographic properties of the surfaces and scale linearly with the applied load. In line with the friction coefficient, we define the slope of this linear plot as the stick slip amplitude coeffident (SSAC). We suggest that such stick slip behaviors are characteristics of surfaces with nanotextures and that such local frictional instabilities have important implications to surface damage and wear. We thus propose that the shear characteristics of the nanodomed surfaces cannot be fully described by the framework of Amontons' laws of friction and that additional parameters (e.g., a, and SSAQ are required, when their friction, lubrication, and wear properties are important considerations in related nanodevices.
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| 6. |
- Vernet, Nicolas, et al.
(författare)
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Experimental determination of the permeability of engineering textiles : Benchmark II
- 2014
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Elsevier Ltd. - 1359-835X .- 1878-5840. ; 61, s. 172-184
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Tidskriftsartikel (refereegranskat)abstract
- In this second international permeability benchmark, the in-plane permeability values of a carbon fabric were studied by twelve research groups worldwide. One participant also investigated the deformation of the tested carbon fabric. The aim of this work was to obtain comparable results in order to make a step toward standardization of permeability measurements. Unidirectional injections were thus conducted to determine the unsaturated in-plane permeability tensor of the fabric. Procedures used by participants were specified in the guidelines defined for this benchmark. Participants were asked to use the same values for parameters such as fiber volume fraction, injection pressure and fluid viscosity to minimize sources of scatter. The comparison of the results from each participant was encouraging. The scatter between data obtained while respecting the guidelines was below 25%. However, a higher dispersion was observed when some parameters differed from the recommendations of this exercise.
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| 7. |
- Ahlgren, Bengt, et al.
(författare)
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Content, Connectivity and Cloud: Ingredients for the Network of the Future
- 2011. - 9
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Ingår i: IEEE Communications Magazine. - : IEEE Communications Society. - 0163-6804 .- 1558-1896. ; 49, s. 62-70
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Tidskriftsartikel (refereegranskat)abstract
- A new network architecture for the Internet needs ingredients from three approaches: information-centric networking, cloud computing integrated with networking, and open connectivity. Information-centric networking considers pieces of information as first-class entities of a networking architecture, rather than only indirectly identifying and manipulating them via a node hosting that information; this way, information becomes independent from the devices they are stored in, enabling efficient and application-independent information caching in the network. Cloud networking offers a combination and integration of cloud computing and virtual networking. It is a solution that distributes the benefits of cloud computing more deeply into the network, and provides a tighter integration of virtualisation features at computing and networking levels. To support these concepts, open connectivity services need to provide advanced transport and networking mechanisms, making use of network and path diversity (even leveraging direct optical paths) and encoding techniques, and dealing with ubiquitous mobility of user, content and information objects in a unified way.
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| 8. |
- Aylett, Ruth, et al.
(författare)
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Do i remember you? : Memory and identity in multiple embodiments
- 2013
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Ingår i: Proceedings - IEEE International Workshop on Robot and Human Interactive Communication. - 9781479905072 ; , s. 143-148
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Konferensbidrag (refereegranskat)abstract
- This paper investigates user perceptions of continuous identity as agents migrate between different embodiments. It reports an experiment seeking to establish whether migrating or not migrating the interaction memory of the agent would affect the user's perception of consistent agent identity over different embodiments. The experiment involved a treasure hunt in which a virtual agent migrated from a screen to a mobile phone in order to accompany a user while they searched for clues. A total of 45 subjects took part in three different conditions with 15 subjects in each. The outcome showed that the presence of memory affected the competence users ascribed to the virtual agent. However it had no significant effect on a strong perception of consistent identity across multiple embodiments.
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| 9. |
- Benser, Jasmin, et al.
(författare)
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Impact of physical activity and cardiovascular fitness on total homocysteine concentrations in European adolescents : The HELENA study
- 2015
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Ingår i: Journal of Nutritional Science and Vitaminology. - : Center for Academic Publications Japan. - 0301-4800 .- 1881-7742. ; 61:1, s. 45-54
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Tidskriftsartikel (refereegranskat)abstract
- We examined the association of physical activity (PA), cardiovascular fitness (CVF) and fatness with total homocysteine (tHcy) concentrations in European adolescents. The present study comprised 713 European adolescents aged 14.8±1.2 y (females 55.3%) from the multicenter HELENA cross-sectional study. PA was assessed through accelerometry, CVF by the 20-m shuttle run test, and body fat by skinfold thicknesses with the Slaughter equation. Plasma folate, cobalamin, and tHcy concentrations were measured. To examine the association of tHcy with PA, CVF, and fatness after controlling for a set of confounders including age, maturity, folate, cobalamin, creatinine, smoking, supplement use, and methylenetetrahydrofolate reductase 677 genotype (CC 47%, CT 43%, TT 10%), bivariate correlations followed by multiple regression models were performed. In the bivariate correlation analysis, tHcy concentrations were slightly negatively correlated (p<0.0 5) with CVF in females (measured both by stages: r=-0.118 and by VO 2 max: r=-0.10 2) and positively with body mass index (r=0.10 0). However, daily time spent with moderate and vigorous PA showed a weak positive association with tHcy in females (p<0.0 5). tHcy concentrations showed a tendency to decrease with increasing CVF and increase with increasing BMI in female European adolescents. However, tHcy concentrations were positively associated with moderate and vigorous PA in female European adolescents.
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| 10. |
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