| 1. |
- Kattge, Jens, et al.
(författare)
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TRY plant trait database - enhanced coverage and open access
- 2020
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Ingår i: Global Change Biology. - : Wiley-Blackwell. - 1354-1013 .- 1365-2486. ; 26:1, s. 119-188
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Tidskriftsartikel (refereegranskat)abstract
- Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives.
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| 2. |
- Liu, Zonghao, et al.
(författare)
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Gas-solid reaction based over one-micrometer thick stable perovskite films for efficient solar cells and modules
- 2018
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Besides high efficiency, the stability and reproducibility of perovskite solar cells (PSCs) are also key for their commercialization. Herein, we report a simple perovskite formation method to fabricate perovskite films with thickness over 1 mu m in ambient condition on the basis of the fast gas-solid reaction of chlorine-incorporated hydrogen lead triiodide and methylamine gas. The resultant thick and smooth chlorine-incorporated perovskite films exhibit full coverage, improved crystallinity, low surface roughness and low thickness variation. The resultant PSCs achieve an average power conversion efficiency of 19.1 +/- 0.4% with good reproducibility. Meanwhile, this method enables an active area efficiency of 15.3% for 5 cmx 5 cm solar modules. The un-encapsulated PSCs exhibit an excellent T-80 lifetime exceeding 1600 h under continuous operation conditions in dry nitrogen environment.
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| 3. |
- Zhou, Yu, et al.
(författare)
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Revealing the Contribution of Individual Factors to Hydrogen Evolution Reaction Catalytic Activity
- 2018
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Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 30:18
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Tidskriftsartikel (refereegranskat)abstract
- For the electrochemical hydrogen evolution reaction (HER), the electrical properties of catalysts can play an important role in influencing the overall catalytic activity. This is particularly important for semiconducting HER catalysts such as MoS2, which has been extensively studied over the last decade. Herein, on-chip microreactors on two model catalysts, semiconducting MoS2 and semimetallic WTe2, are employed to extract the effects of individual factors and study their relations with the HER catalytic activity. It is shown that electron injection at the catalyst/current collector interface and intralayer and interlayer charge transport within the catalyst can be more important than thermodynamic energy considerations. For WTe2, the site-dependent activities and the relations of the pure thermodynamics to the overall activity are measured and established, as the microreactors allow precise measurements of the type and area of the catalytic sites. The approach presents opportunities to study electrochemical reactions systematically to help establish rational design principles for future electrocatalysts.
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| 4. |
- Zhou, Yu, et al.
(författare)
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Unveiling the Interfacial Effects for Enhanced Hydrogen Evolution Reaction on MoS2/WTe2 Hybrid Structures
- 2019
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Ingår i: Small. - : Wiley-VCH Verlagsgesellschaft. - 1613-6810 .- 1613-6829. ; 15:19
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Tidskriftsartikel (refereegranskat)abstract
- Using the MoS2-WTe2 heterostructure as a model system combined with electrochemical microreactors and density function theory calculations, it is shown that heterostructured contacts enhance the hydrogen evolution reaction (HER) activity of monolayer MoS2. Two possible mechanisms are suggested to explain this enhancement: efficient charge injection through large-area heterojunctions between MoS2 and WTe2 and effective screening of mirror charges due to the semimetallic nature of WTe2. The dielectric screening effect is proven minor, probed by measuring the HER activity of monolayer MoS2 on various support substrates with dielectric constants ranging from 4 to 300. Thus, the enhanced HER is attributed to the increased charge injection into MoS2 through large-area heterojunctions. Based on this understanding, a MoS2/WTe2 hybrid catalyst is fabricated with an HER overpotential of -140 mV at 10 mA cm(-2), a Tafel slope of 40 mV dec(-1), and long stability. These results demonstrate the importance of interfacial design in transition metal dichalcogenide HER catalysts. The microreactor platform presents an unambiguous approach to probe interfacial effects in various electrocatalytic reactions.
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| 5. |
- Baber, Ashleigh E., et al.
(författare)
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Stabilization of Catalytically Active Cu plus Surface Sites on TitaniumCopper Mixed-Oxide Films**
- 2014
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Ingår i: Angewandte Chemie International Edition. - : Gesellschaft Deutscher Chemiker. - 1433-7851 .- 1521-3773. ; 53:21, s. 5336-5340
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Tidskriftsartikel (refereegranskat)abstract
- The oxidation of CO is the archetypal heterogeneous catalytic reaction and plays a central role in the advancement of fundamental studies, the control of automobile emissions, and industrial oxidation reactions. Copper-based catalysts were the first catalysts that were reported to enable the oxidation of CO at room temperature, but a lack of stability at the elevated reaction temperatures that are used in automobile catalytic converters, in particular the loss of the most reactive Cu+ cations, leads to their deactivation. Using a combined experimental and theoretical approach, it is shown how the incorporation of titanium cations in a Cu2O film leads to the formation of a stable mixed-metal oxide with a Cu+ terminated surface that is highly active for CO oxidation.
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| 6. |
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| 7. |
- Jiang, Yan, et al.
(författare)
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Negligible-Pb-Waste and Upscalable Perovskite Deposition Technology for High-Operational-Stability Perovskite Solar Modules
- 2019
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Ingår i: Advanced Energy Materials. - : Wiley-VCH Verlagsgesellschaft. - 1614-6832 .- 1614-6840. ; 9:13
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Tidskriftsartikel (refereegranskat)abstract
- An upscalable perovskite film deposition method combining raster ultrasonic spray coating and chemical vapor deposition is reported. This method overcomes the coating size limitation of the existing stationary spray, single-pass spray, and spin-coating methods. In contrast with the spin-coating method (>90% Pb waste), negligible Pb waste during PbI2 deposition makes this method more environmentally friendly. Outstanding film uniformity across the entire area of 5 cm x 5 cm is confirmed by both large-area compatible characterization methods (electroluminescence and scattered light imaging) and local characterization methods (atomic force microscopy, scanning electron microscopy, photoluminescence mapping, UV-vis, and X-ray diffraction measurements on multiple sample locations), resulting in low solar cell performance decrease upon increasing device area. With the FAPb(I0.85Br0.15)(3) (FA = formamidinium) perovskite layer deposited by this method, champion solar modules show a power conversion efficiency of 14.7% on an active area of 12.0 cm(2) and an outstanding shelf stability (only 3.6% relative power conversion efficiency decay after 3600 h aging). Under continuous operation (1 sun light illumination, maximum power point condition, dry N-2 atmosphere with <5% relative humidity, no encapsulation), the devices show high light-soaking stability corresponding to an average T-80 lifetime of 535 h on the small-area solar cells and 388 h on the solar module.
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| 8. |
- Lin, Fengxiang, et al.
(författare)
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Comment : On the nature of “unconventional twins” in magnesium
- 2023
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Ingår i: Scripta Materialia. - : Acta Materialia Inc. - 1359-6462 .- 1872-8456. ; 224
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Tidskriftsartikel (refereegranskat)abstract
- “Unconventional twins” were reported by Cayron and Logé [1] to form in plastically deformed magnesium. They were used to show the occurrence of a new twinning mode which was used to argue for reconsidering the theory of deformation twinning that is based on simple shear [1], and to support a concept of axial weak twins [2]. Our paper demonstrates the incorrect interpretation of their electron back-scatter diffraction map in [1], and that the so-called “unconventional” twins are just conventional extension twins that have impinged with each other. Therefore, the so-called habit plane of the “unconventional twins” is a boundary resulting from impingement of these two different variants of the extension twin, and is therefore not expected to be invariant. © 2022 Acta Materialia Inc.
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| 9. |
- Liu, H., et al.
(författare)
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Formation and autocatalytic nucleation of co-zone {101¯2} deformation twins in polycrystalline Mg : A phase field simulation study
- 2018
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Ingår i: Acta Materialia. - : Elsevier. - 1359-6454 .- 1873-2453. ; 153, s. 86-107
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Tidskriftsartikel (refereegranskat)abstract
- A phase-field model is developed to study the formation and autocatalytic nucleation of {101¯2} twins in polycrystalline Mg. The twins are found to nucleate most favourably in grains with the most negative interaction energy. Within such grains, the energetically most favoured nucleation site is determined by stresses concentrated near the grain boundaries that are related to the elastic anisotropy of the material. Furthermore, in a structure consisting of three lamellar grains with an incoming twin in the central grain, the simulation results show that before autocatalytic nucleation, the incoming twin often has a lenticular shape. The stress field around the tip of the incoming twin plays the major role in the autocatalytic nucleation. After a twin has nucleated in the neighbouring grain, the incoming and the outgoing twins evolve simultaneously, and the shape of the incoming twin gradually changes from lenticular to parallel-sided plate. Under the condition that the crystallographic orientation of the central grain and the applied strain remains unchanged, the driving force for twin nucleation decreases with increasing misorientation (up to 90°) across the grain boundary. It is further derived that the interaction energy values between the pre-existing stress field of the polycrystalline structure and the eigenstrain of the to-be-nucleated twin is mathematically related to the resolved shear stress of twins. © 2018 Acta Materialia Inc.
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| 10. |
- Liu, H., et al.
(författare)
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Precipitation during high temperature aging of Al−Cu alloys : A multiscale analysis based on first principles calculations
- 2019
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Ingår i: Acta Materialia. - : Elsevier. - 1359-6454 .- 1873-2453. ; 167, s. 121-135
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Tidskriftsartikel (refereegranskat)abstract
- Precipitation during high temperature aging of Al−Cu alloys is analysed by means of the integration of classical nucleation theory and phase-field simulations into a multiscale modelling approach based on well-established thermodynamics principles. In particular, thermal stability of θ'', θ′ and θ precipitates was assessed from first principles calculations of the Helmholtz free energy while homogeneous and heterogeneous nucleation of θ'' and θ′ was analysed using classical nucleation theory. Precipitate growth was finally computed by means of a mesoscopic phase-field model. The model parameters that determine quantitatively the driving forces for each transformation were obtained by means of first principles calculations and computational thermodynamics. The predictions of the models were in good agreement with experimental results and provided a comprehensive understanding of the precipitation pathway in Al−Cu alloys. It is envisaged that the strategy presented in this investigation can be used in the future to design optimum microstructures based on the information of the different energy contributions obtained from first principles calculations. © 2019 Acta Materialia Inc.
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