| 1. |
- Chen, Desui, et al.
(författare)
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Shelf-Stable Quantum-Dot Light-Emitting Diodes with High Operational Performance
- 2020
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Ingår i: Advanced Materials. - : Wiley-VCH Verlagsgesellschaft. - 0935-9648 .- 1521-4095. ; 32
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Tidskriftsartikel (refereegranskat)abstract
- Quantum-dot light-emitting diodes (QLEDs) promise a new generation of high-performance, large-area, and cost-effective electroluminescent devices for both display and solid-state lighting technologies. However, a positive ageing process is generally required to improve device performance for state-of-the-art QLEDs. Here, it is revealed that the in situ reactions induced by organic acids in the commonly used encapsulation acrylic resin lead to positive ageing and, most importantly, the progression of in situ reactions inevitably results in negative ageing, i.e., deterioration of device performance after long-term shelf storage. In-depth mechanism studies focusing on the correlations between the in situ chemical reactions and the shelf-ageing behaviors of QLEDs inspire the design of an electron-transporting bilayer, which delivers both improved electrical conductivity and suppressed interfacial exciton quenching. This material innovation enables red QLEDs exhibiting neglectable changes of external quantum efficiency (>20.0%) and ultralong operational lifetime (T-95: 5500 h at 1000 nits) after storage for 180 days. This work provides design principles for oxide electron-transporting layers to realize shelf-stable and high-operational-performance QLEDs, representing a new starting point for both fundamental studies and practical applications.
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| 2. |
- Gao, Yun, et al.
(författare)
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Microsecond-response perovskite light-emitting diodes for active-matrix displays
- 2024
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Ingår i: NATURE ELECTRONICS. - : NATURE PORTFOLIO. - 2520-1131. ; 7:6
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Tidskriftsartikel (refereegranskat)abstract
- Perovskite light-emitting diodes (PeLEDs) could be of use in the development of active-matrix displays. However, due to ion migration in crystal structure, PeLEDs have electroluminescence rise times over milliseconds, which is problematic for the development of high-refresh-rate displays. Here, we show that the electroluminescence rise time of PeLEDs can be reduced to microseconds using an individual-particle passivation strategy. The approach is based on BF4 - ions that can passivate every nanocrystal in a perovskite emissive layer during film deposition. It leads to a defect-free film with discrete nanostructure and excellent crystallinity, which inhibits ion migration. Our strategy can be applied in perovskite nanocrystal films with different colours: red (635 nm), green (520 nm) and blue (475 nm). These PeLEDs all demonstrate response times within microseconds and high external quantum efficiencies of 22.7%, 26.2% and 18.1%, respectively. This allows us to create microsecond-response active-matrix PeLEDs that exhibit external quantum efficiencies above 20% at a display brightness of 500-3,000 cd m-2 for green devices with a resolution of 30 pixels per inch. We also develop microsecond-response red, green and blue active-matrix displays with 90 pixels per inch. An individual-particle passivation strategy that reduces ion migration in perovskite nanocrystal film can be used to make high-refresh-rate active-matrix displays with microsecond response times reduced by three orders of magnitude compared with typical perovskite light-emitting diodes.
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| 3. |
- Zhang, Xingliang, et al.
(författare)
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Challenges in defining the base of Cambrian Series 2 and Stage 3
- 2017
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Ingår i: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 172, s. 124-139
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Tidskriftsartikel (refereegranskat)abstract
- Formal subdivision of the Cambrian System into four series and ten stages is in progress. The base of Cambrian Stage 3 (provisional), which is conterminous with the base of Cambrian Series 2 (provisional), is expected to be placed at a horizon close to the first appearance of trilobites, which marks the onset of the largest phase of the Cambrian explosion. Conceptually, an ideal boundary position would be marked by a significant and globally recognizable bioevent that divides the lower part of the Cambrian System into a sub-trilobitic Terreneuvian Series and a trilobite-dominated Series 2. If the level is to be identified principally through biostratigraphic means, its position also needs to be recognizable using non-biostratigraphic means, and its correlation potential should be tested through detailed investigation of several continuous successions embracing the critical interval. Major difficulties in identifying a suitable horizon include strong biotic provincialism, a plethora of regional unconformities, and facies changes on different paleocontinents in the Cambrian Terreneuvian–Series 2 boundary interval. Levels that provide potential for intercontinental correlation include the first appearance position of trilobites and the approximately equivalent first appearance positions of certain small shelly fossil and acritarch species. In addition, a non-biostratigraphic marker, such as a stable carbon isotopic excursion, may be useful as a correlation level. Cambrian Series 2 and Stage 3 are provisional stratigraphic units, and their conterminous base was previously suggested to coincide to the appearance of trilobites. Compared to other potential chronostratigraphic indicators, the first appearance of trilobites still has advantages for recognizing and correlating the base of Stage 3, and should remain as the provisional primary marker for the boundary position.
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| 4. |
- Zhang, Zhifei, et al.
(författare)
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A sclerite-bearing stem group entoproct from the early Cambrian and its implications
- 2013
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Ingår i: Scientific Reports. - London : Nature Publishing Group. - 2045-2322. ; 3, s. 1-7
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Tidskriftsartikel (refereegranskat)abstract
- The Lophotrochozoa includes disparate tentacle-bearing sessile protostome animals, which apparently appeared in the Cambrian explosion, but lack an uncontested fossil record. Here we describe abundant well preserved material of Cotyledion tylodes Luo et Hu, 1999, from the Cambrian (Series 2) Chengjiang deposits, reinterpreted here as a stem-group entoproct. The entoproct affinity is supported by the sessile body plan and interior soft anatomy. The body consists of an upper calyx and a lower elongate stalk with a distal holdfast. The soft anatomy includes a U-shaped gut with a mouth and aboral anus ringed by retractable marginal tentacles. Cotyledion differs from extant entoprocts in being larger, and having the calyx and the stalk covered by numerous loosely-spaced external sclerites. The description of entoprocts from the Chengjiang biota traces the ancestry of yet another lophotrochozoan phylum back to the Cambrian radiation, and has important implications for the earliest evolution of lophotrochozoans.
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| 5. |
- Fu, Dongjing, et al.
(författare)
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Ontogeny and dimorphism of Isoxys auritus (Arthropoda) from the Early Cambrian Chengjiang biota, South China
- 2014
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Ingår i: Gondwana Research. - : Elsevier BV. - 1342-937X .- 1878-0571. ; 25:3, s. 975-982
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Tidskriftsartikel (refereegranskat)abstract
- The morphology of Isoxys auritus Jiang, 1982 is reinterpreted in the light of abundant new specimens from the Early Cambrian Chengjiang biota, South China. I. auritus was a bivalved arthropod, its shield armed with two cardinal spines sub-equal in length. Two morphotypes (shield with and without ornamentation) which are of several original differences were interpreted as sexual dimorphs. 81 specimens examined here, which range between 4.8 mm and 47.0 mm, represent a successive developmental sequence. The earliest stages were characterized by short cardinal spines, large spherical eyes, a pair of elongated antennulae, and seven pairs of post-antennular appendages. The slim antennula is uniramous, consisting of nine articles, each armed with short spines. It differs from that of great appendage and lacks any grasping function. During the ontogeny, the body length increases, accompanied by addition of trunk somites and appearance of primary reticulated ornaments, and both cardinal spines become evident. In the fully grown adult, there are up to 11 pairs of post-antennular appendages, equipped with the stout endopod composed of 6 or 7 podomeres lacking endites, and a terminal claw; the paddle shaped exopod is fringed with long setae along its posterior margin. Secondary reticulation of the shield has developed inside each primary one; the cardinal spines more elongated; and the ratio of length to height of shield increases. However, the size of eye and antennula relative to the body length significantly decreases. Accordingly, intraspecific variation, including sexual dimorphs and developmental change, is evident in I. auritus. Recognizing such differences is important for detecting possible synonymies in the genus. Furthermore, the ontogenetic changes of I. auritus described here, particularly the postembryonic segment addition and possible allometric growth may also improve our understanding of development of Cambrian arthropods in Burgess-shale type preservation, especially those possessing such a large shield. (C) 2013 International Association for Gondwana Research. Published by Elsevier ay. All rights reserved.
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| 6. |
- Fu, Dongjing, et al.
(författare)
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The evolution of biramous appendages revealed by a carapace-bearing Cambrian arthropod
- 2022
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Ingår i: Philosophical Transactions of the Royal Society of London. Biological Sciences. - : ROYAL SOC. - 0962-8436 .- 1471-2970. ; 377:1847
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Tidskriftsartikel (refereegranskat)abstract
- Biramous appendages are a common feature among modern marine arthropods that evolved deep in arthropod phylogeny. The branched appendage of Cambrian arthropods has long been considered as the ancient biramous limb, sparking numerous investigations on its origin and evolution. Here, we report a new arthropod, Erratus sperare gen. et sp. nov., from the Lower Cambrian (Stage 3, 520 Ma) Chengjiang biota of Yunnan, China, with unique trunk appendages formed of lateral anomalocaridid-type flaps and ventral subconical endopods. These appendages represent an intermediate stage of biramous limb evolution, i.e. from 'two pairs of flap appendages' in radiodonts to 'flap + endopod' in Erratus, to 'exopod + endopod' in the rest of carapace-bearing arthropods that populate the basal region of the upper-stem lineage arthropods (deuteropods). The new species occupies a phylogenetic position at the first node closer to deuteropods than to radiodonts, and therefore pinpoints the earliest occurrence of the endopod within Deuteropoda. The primitive endopod is weakly sclerotized, and has unspecialized segments without endites or claw. The findings might support previous claims that the outer branch of the biramous limb of fossil marine arthropods, such as trilobites, is not a true exopod, but is instead a modified exite. This article is part of the theme issue 'The impact of Chinese palaeontology on evolutionary research'.
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| 7. |
- Fu, Dongjing, et al.
(författare)
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The first dorsal-eyed bivalved arthropod and its significance for early arthropod evolution
- 2014
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Ingår i: GFF. - : Informa UK Limited. - 1103-5897 .- 2000-0863. ; 136:1, s. 80-84
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Tidskriftsartikel (refereegranskat)abstract
- A new bivalved arthropod Erjiecaris minusculo gen. et sp. nov. is described from the Lower Cambrian Chengjiang Lagerstatte, Yunnan, southwest China. It possesses mosaic features, such as the reduced shield that is dorsoventrally flattened, dorsally positioned eyes, ring-shaped somites and broad furcal rami. These provide an important link for assessing the evolutionary morphological gap between two distinctive Cambrian arthropod groups, crustaceanomorph and trilobite-like taxa. Thus, the new finding reported here in turn improves the understanding of the body plan of early arthropods and provides fresh insight into the evolution of the carapace/head shield and visual system.
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| 8. |
- Huang, Yanqin, et al.
(författare)
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Humic Acids Combined with Dairy Slurry as Fertilizer Can Increase Alfalfa Yield and Reduce Nitrogen Losses
- 2024
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Ingår i: Agriculture. - : Multidisciplinary Digital Publishing Institute (MDPI). - 2077-0472. ; 14:8
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Tidskriftsartikel (refereegranskat)abstract
- Dairy slurry could be a significant source of nitrogen (N) for plants, but mismanagement can lead to atmospheric ammonia losses or nitrate leaching into groundwater. To make the use of dairy slurry efficient and reasonable, the loss of N pollution to the environment should be reduced. We used repacked lysimeters to comprehensively determine ammonia emission and N leaching losses in an alfalfa–soil system. The application of dairy slurry had no significant effect on alfalfa yield at the same rate of N application in comparison to chemical fertilizer, and adding humic acids significantly increased yield by about 12%. However, the application of dairy slurry increased the ammonia emission rate significantly, leading to an increase in the cumulative amount of ammonia emission, while the addition of humic acids reduced the ammonia emissions by 11%. Chemical fertilizer and dairy slurry application significantly increased nitrate leaching compared to the control treatment, while the addition of humic acids can significantly reduce ammonium N leaching. Dairy slurry was proven to be as effective as chemical N fertilizer in achieving the optimum biomass, and adding humic acids can significantly reduce N loss to the atmosphere and groundwater. This study showed the possibility of replacing chemical fertilizer with dairy slurry in alfalfa production and the advantages of humic acids’ addition to alfalfa to maintain production yield and improve environmental friendliness.
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| 9. |
- Li, Luoyang, et al.
(författare)
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Fibrous or Prismatic? A Comparison of the Lamello-Fibrillar Nacre in Early Cambrian and Modern Lophotrochozoans
- 2023
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Ingår i: Biology. - : MDPI. - 2079-7737. ; 12:1, s. 113-113
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Tidskriftsartikel (refereegranskat)abstract
- The Precambrian–Cambrian interval saw the first appearance of disparate modern metazoan phyla equipped with a wide array of mineralized exo- and endo-skeletons. However, the current knowledge of this remarkable metazoan skeletonization bio-event and its environmental interactions is limited because uncertainties have persisted in determining the mineralogy, microstructure, and hierarchical complexity of these earliest animal skeletons. This study characterizes in detail a previously poorly understood fibrous microstructure—the lamello-fibrillar (LF) nacre—in early Cambrian mollusk and hyolith shells and compares it with shell microstructures in modern counterparts (coleoid cuttlebones and serpulid tubes). This comparative study highlights key differences in the LF nacre amongst different lophotrochozoan groups in terms of mineralogical compositions and architectural organization of crystals. The results demonstrate that the LF nacre is a microstructural motif confined to the Mollusca. This study demonstrates that similar fibrous microstructure in Cambrian mollusks and hyoliths actually represent a primitive type of prismatic microstructure constituted of calcitic prisms. Revision of these fibrous microstructures in Cambrian fossils demonstrates that calcitic shells are prevalent in the so-called aragonite sea of the earliest Cambrian. This has important implications for understanding the relationship between seawater chemistry and skeletal mineralogy at the time when skeletons were first acquired by early lophotrochozoan biomineralizers.
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| 10. |
- Li, Luoyang, et al.
(författare)
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HOMOLOGOUS SHELL MICROSTRUCTURES INCAMBRIAN HYOLITHS AND MOLLUSCS
- 2019
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Ingår i: Palaeontology. - : Wiley. - 0031-0239 .- 1475-4983. ; 62:4, s. 515-532
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Tidskriftsartikel (refereegranskat)abstract
- Hyoliths were among the earliest biomineralizingmetazoans in Palaeozoic marine environments. They havebeen known for two centuries and widely assigned tolophotrochozoans. However, their origin and relationshipswith modern lophotrochozoan clades have been a longstand-ing palaeontological controversy. Here, we provide broadmicrostructural data from hyolith conchs and opercula fromthe lower Cambrian Xinji Formation of North China, includ-ing two hyolithid genera and four orthothecid genera as wellas unidentified opercula. Results show that most hyolithconchs contain a distinct aragonitic lamellar layer that is com-posed of foliated aragonite, except in the orthothecid Newtaxon 1 that has a crossed foliated lamellar microstructure.Opercula are mostly composed of foliated aragonite andoccasionally foliated calcite. These blade or lath-likemicrostructural fabrics coincide well with biomineralizationof Cambrian molluscs rather than lophophorates, as exempli-fied by the Cambrian members of the tommotiid-brachiopodlinage. Accordingly, we propose that hyoliths and molluscsmight have inherited their biomineralized skeletons from anon-mineralized or weakly mineralized common ancestorrather than as a result of convergence. Consequently, fromthe view of biomineralization, the homologous shellmicrostructures in Cambrian hyoliths and molluscs stronglystrengthen the phylogenetic links between the two groups.
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