| 1. |
- Kehoe, Laura, et al.
(författare)
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Make EU trade with Brazil sustainable
- 2019
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 364:6438, s. 341-
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 2. |
- Aboulfadl, Hisham, 1986, et al.
(författare)
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Alkali Dispersion in (Ag,Cu)(In,Ga)Se2 Thin Film Solar Cells - Insight from Theory and Experiment
- 2021
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Ingår i: ACS Applied Materials & Interfaces. - : American Chemical Society (ACS). - 1944-8252 .- 1944-8244. ; 13:6, s. 7188-7199
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Tidskriftsartikel (refereegranskat)abstract
- Silver alloying of Cu(In,Ga)Se2 absorbers for thin film photovoltaics offers improvements in open-circuit voltage, especially when combined with optimal alkali-treatments and certain Ga concentrations. The relationship between alkali distribution in the absorber and Ag alloying is investigated here, combining experimental and theoretical studies. Atom probe tomography analysis is implemented to quantify the local composition in grain interiors and at grain boundaries. The Na concentration in the bulk increases up to ∼60 ppm for [Ag]/([Ag] + [Cu]) = 0.2 compared to ∼20 ppm for films without Ag and up to ∼200 ppm for [Ag]/([Ag] + [Cu]) = 1.0. First-principles calculations were employed to evaluate the formation energies of alkali-on-group-I defects (where group-I refers to Ag and Cu) in (Ag,Cu)(In,Ga)Se2 as a function of the Ag and Ga contents. The computational results demonstrate strong agreement with the nanoscale analysis results, revealing a clear trend of increased alkali bulk solubility with the Ag concentration. The present study, therefore, provides a more nuanced understanding of the role of Ag in the enhanced performance of the respective photovoltaic devices.
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| 3. |
- Barabash, Stas, et al.
(författare)
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Towards low-cost Swedish planetary missions
- 2004
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- As a continuation of the Swedish tradition of designing small and high-quality spacecrafts such as Freja, Astrid, Munin, and SMART-1, Swedish scientists and engineers have proposed aggressive but feasible missions as the next national-level target: (1) an interplanetary plasma module (or subsatellite) Saga, and (2) a technology mission Prisma. The Saga micro-satellite contains a separation mechanism, technologically-challenging communication package, and plasma payload with an estimated total mass of 37kg to make the mission possible with a piggy-back launch or by attaching to another planetary mission. The Prisma mission consists of a semi-coordinated dual micro- and nano-satellites flying together in Earth orbit with state-of-art instruments to test. Both projects aim to develop and test new key spacecraft technologies.
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| 4. |
- Cederwall, Bo, et al.
(författare)
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Evidence for a spin-aligned neutron-proton paired phase from the level structure of 92Pd
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 469:7328, s. 68-71
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Tidskriftsartikel (refereegranskat)abstract
- Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.
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| 5. |
- Ericsson, Stefan, et al.
(författare)
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Towards automatic detection of local bearing defects in rotating machines
- 2005
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Ingår i: Mechanical systems and signal processing. - : Elsevier BV. - 0888-3270 .- 1096-1216. ; 19:3, s. 509-535
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Tidskriftsartikel (refereegranskat)abstract
- In this paper we derive and compare several different vibration analysis techniques for automatic detection of local defects in bearings. Based on a signal model and a discussion on to what extent a good bearing monitoring method should trust it, we present several analysis tools for bearing condition monitoring and conclude that wavelets are especially well suited for this task. Then we describe a large-scale evaluation of several different automatic bearing monitoring methods using 103 laboratory and industrial environment test signals for which the true condition of the bearing is known from visual inspection. We describe the four best performing methods in detail (two wavelet-based, and two based on envelope and periodisation techniques). In our basic implementation, without using historical data or adapting the methods to (roughly) known machine or signal parameters, the four best methods had 9-13% error rate and are all good candidates for further fine-tuning and optimisation. Especially for the wavelet-based methods, there are several potentially performance improving additions, which we finally summarise into a guiding list of suggestion.
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| 6. |
- Gulliksen, Jan, et al.
(författare)
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Accessibility and Public Policy in Sweden
- 2010
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Ingår i: interactions. - : Association for Computing Machinery (ACM). - 1072-5520 .- 1558-3449. ; 17:3, s. 26-29
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Tidskriftsartikel (refereegranskat)abstract
- Principles and guidelines will become more important, due to the development of accessibility policies and the harmonization with Europe in Sweden is discussed. Public policy is the body of principles that underpin the operation of legal systems in a state, which address the social, moral, and economic values that tie a society together. Accessibility policies often start at the international level. Many countries currently have different regulations for interface accessibility. In Sweden the transparency of the public sector is one of the foundations of democracy and the development of an accessible society and is manifested by a duty to publish and promote openness. Public policy and legislation play an important role in contributing to increased accessibility. Sweden is a country of negotiation and transparency, not binding legislation. Involving groups with impairments may not only provide increased accessibility but also increase innovation.
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| 7. |
- Gulliksen, Jan, 1965-, et al.
(författare)
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Making a difference : a survey of the usability profession in Sweden
- 2004
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Ingår i: Proceedings of the third Nordic conference on Human-computer interaction. - New York : ACM Press. - 1581138571 ; , s. 207-215
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Konferensbidrag (refereegranskat)abstract
- Poor usability in interactive systems/products is still a major problem for users and buyers, despite efforts made by an increasing number of usability professionals. How come this is so and what are the main obstacles to usability work? In this paper we report the results of a survey of usability professionals in Sweden, conducted in 2003. The survey identified, e.g. their background and experiences, the type of employment, organization, and products/systems, the software development process being used and some key success factors for usability work. The results indicate, among other things, that management support and project management support are essential for the usability worker. Moreover, they face problems such as, usability and user involvement having low priority in the projects.
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| 8. |
- Gustafsson, Oscar, et al.
(författare)
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Photoluminescence photoresponse from InSb/InAs-based quantum dot structures
- 2012
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Ingår i: Optics Express. - : Optical Society of America. - 1094-4087. ; 20:19, s. 21264-71
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Tidskriftsartikel (refereegranskat)abstract
- InSb-based quantum dots grown by metal-organic vapor-phase epitaxy (MOVPE) on InAs substrates are studied for use as the active material in interband photon detectors. Long-wavelength infrared (LWIR) photoluminescence is demonstrated with peak emission at 8.5 μm and photoresponse, interpreted to originate from type-II interband transitions in a p-i-n photodiode, was measured up to 6 μm, both at 80 K. The possibilities and benefits of operation in the LWIR range (8-12 μm) are discussed and the results suggest that InSb-based quantum dot structures can be suitable candidates for photon detection in the LWIR regime.
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| 9. |
- Hedlund-Åström, Anna, 1957-
(författare)
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Model for End of Life Treatment of Polymer Composite Materials
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Because of increasing environmental demands, especially on dealing with products end of life phase, product manufacturers and designers must consider the future disposal of their products. For conventional materials like steel and aluminium well-functioning recycling methods exists. This is not the case for structures of polymer composites, which are used more extensively, especially for structures like vehicles and vessels. Several techniques do exist but they are not yet commercially available. The current disposal methods of polymer composites are landfill and incineration. Polymer composites are materials, which consist of several materials like fibre, matrix, and additives. In the form of sandwich constructions also foam core material is added. This circumstance complicates the waste treatment of composite materials. In this thesis a model for assessing possible future waste treatment techniques for polymer composites including sandwich structures is presented. The model is meant to be used as an aid for preparing future disposal for end of life products for planning waste treatment and for facilitating communication in contacts with waste receivers. Recommendations for waste treatment have been formed for a number of polymer composites. These recommendations are based on the analysis of costs and environmental effects and they compare different scenarios for mechanical material recycling and energy recovery by waste incineration. The result of this study points out material recycling as the preferable method for the main part of the studied materials. But this recommendation is strongly dependent on type of virgin material replaced by the recycled material. Energy recovery can also be considered if the polymer composite waste replaces coal, which is non renewable. Though incineration will always result in a cost for the waste producer. In the recommendations mentioned above no information concerning implementation of the different waste disposal techniques is included. Therefore, in this study a model for assessing possible waste disposal techniques for polymer composites is presented. The model is based on internal factors, which are related to the waste and to the processes. To implement the model relevant waste properties must be identified in order to fulfil the conditions set by the required processes involved. A case study was carried out using the proposed model for assessing different waste disposal techniques for the hull of the Visby Class Corvette in the Royal Swedish Navy. Six different techniques were studied for the hull structure. Since almost all the important waste properties were known and the waste was assessed to be treatable all the included techniques except one are shown to be usable in the future. Many investigations have pointed out material recycling as the best alternative considering environmental effects. This is also valid for polymer composite materials. Since recycling polymer composites is a complicated process, especially recycling thermoset composite it is important to aquire comprehensive information about the constituents of these materials.
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| 10. |
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