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- Mukhamedov, Boburjon, et al.
(författare)
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Tetragonal distortion in magnetron sputtered bcc-W films with supersaturated carbon
- 2022
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Ingår i: Materials & design. - : Elsevier Science Ltd. - 0264-1275 .- 1873-4197. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- Carbon has a low solid solubility in bcc tungsten at equilibrium. However, metastable supersaturated solid solutions can be synthesized with magnetron sputtering. Here, we present a systematic study on the phase stability and mechanical properties of such supersaturated W-C solid solutions. H-2h scans show a split of the 200/020 and the 002 peaks for supersaturated films which is explained by a tetragonal distortion of the bcc structure. This split increases with increasing C content and is maximized at 4 at.% C, where we observe an a/b axis of 3.15-3.16 A and a c-axis of 3.21-3.22 A. We performed first-principles calculations of lattice parameters, mixing enthalpies, elastic constants and polycrystalline elastic moduli for cubic and tetragonal W-C solid solutions. Calculations show that tetragonal structure is more stable than the bcc supersaturated solid solution and the calculated lattice parameters and Youngs moduli follow the same trends as the experimental ones as a function of C concentration. The results suggest that supersaturated films with lattice distortion can be used as a design approach to improve the properties of transition metal films with a bcc structure. (c) 2022 The Authors. Published by Elsevier Ltd.
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| 2. |
- Ottosson, Mikael, 1980-, et al.
(författare)
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Shaping sustainable markets : A conceptual framework illustrated by the case of biogas in Sweden
- 2020
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Ingår i: Environmental Innovation and Societal Transitions. - : Elsevier. - 2210-4224 .- 2210-4232. ; 36, s. 303-320
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Tidskriftsartikel (refereegranskat)abstract
- By merging findings from transition studies with recent literature on market-shaping, this paper outlines a conceptual framework that describes the shaping of sustainable markets. The framework comprises three critical processes: enabling exchange practices, proving the system and constructing the narrative. Individually, these processes generate different kinds of value – traded, demonstrated and expected value – and the value output from each process serves as input to the other two processes. Hence the value streams link the processes together. We illustrate the framework by analyzing market-shaping processes for biogas in Sweden. The case analysis shows how public and private actors have engaged in a multitude of activities that have built up the market-shaping processes. The analysis highlights the recursive nature of sustainable market-shaping, showing how key actors must repeatedly respond to tensions resulting from growth and aspirations of growth.
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| 3. |
- Zubkins, Martins, et al.
(författare)
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Deposition of Ga2O3 thin films by liquid metal target sputtering
- 2023
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Ingår i: Vacuum. - : Elsevier BV. - 0042-207X .- 1879-2715. ; 209, s. 111789-
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports on the deposition of amorphous and crystalline thin films of Ga2O3 by reactive pulsed direct current magnetron sputtering from a liquid gallium target onto fused (f-) quartz and c plane (c-) sapphire sub-strates, where the temperature of the substrate is varied from room temperature (RT) to 800 degrees C. The deposition rate (up to 37 nm/min at RT on f-quartz and 5 nm/min at 800 degrees C on c-sapphire) is two to five times higher than the data given in the literature for radio frequency sputtering. Deposited onto unheated substrates, the films are X-ray amorphous. Well-defined X-ray diffraction peaks of 13-Ga2O3 start to appear at a substrate temperature of 500 degrees C. Films grown on c-sapphire at temperatures above 600 degrees C are epitaxial. However, the high rocking curve full width at half maximum values of X2.4-2.5 degrees are indicative of the presence of defects. A dense and void-free microstructure is observed in electron microscopy images. Composition analysis show stoichiometry close to Ga2O3 and no traces of impurities. The optical properties of low absorptance (<1%) in the visible range and an optical band gap of approximately 5 eV are consistent with the data in the literature for Ga2O3 films produced by other deposition methods.
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