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- 2019
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Tidskriftsartikel (refereegranskat)
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- Blunden, Jessica, et al.
(författare)
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State of the Climate in 2012
- 2013
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - 0003-0007 .- 1520-0477. ; 94:8, s. S1-S258
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Tidskriftsartikel (refereegranskat)abstract
- For the first time in serveral years, the El Nino-Southern Oscillation did not dominate regional climate conditions around the globe. A weak La Ni a dissipated to ENSOneutral conditions by spring, and while El Nino appeared to be emerging during summer, this phase never fully developed as sea surface temperatures in the eastern conditions. Nevertheless, other large-scale climate patterns and extreme weather events impacted various regions during the year. A negative phase of the Arctic Oscillation from mid-January to early February contributed to frigid conditions in parts of northern Africa, eastern Europe, and western Asia. A lack of rain during the 2012 wet season led to the worst drought in at least the past three decades for northeastern Brazil. Central North America also experienced one of its most severe droughts on record. The Caribbean observed a very wet dry season and it was the Sahel's wettest rainy season in 50 years. Overall, the 2012 average temperature across global land and ocean surfaces ranked among the 10 warmest years on record. The global land surface temperature alone was also among the 10 warmest on record. In the upper atmosphere, the average stratospheric temperature was record or near-record cold, depending on the dataset. After a 30-year warming trend from 1970 to 1999 for global sea surface temperatures, the period 2000-12 had little further trend. This may be linked to the prevalence of La Ni a-like conditions during the 21st century. Heat content in the upper 700 m of the ocean remained near record high levels in 2012. Net increases from 2011 to 2012 were observed at 700-m to 2000-m depth and even in the abyssal ocean below. Following sharp decreases in to the effects of La Ni a, sea levels rebounded to reach records highs in 2012. The increased hydrological cycle seen in recent years continued, with more evaporation in drier locations and more precipitation in rainy areas. In a pattern that has held since 2004, salty areas of the ocean surfaces and subsurfaces were anomalously salty on average, while fresher areas were anomalously fresh. Global tropical cyclone activity during 2012 was near average, with a total of 84 storms compared with the 1981-2010 average of 89. Similar to 2010 and 2011, the North Atlantic was the only hurricane basin that experienced above-normal activity. In this basin, Sandy brought devastation to Cuba and parts of the eastern North American seaboard. All other basins experienced either near-or below-normal tropical cyclone activity. Only three tropical cyclones reached Category 5 intensity-all in Bopha became the only storm in the historical record to produce winds greater than 130 kt south of 7 N. It was also the costliest storm to affect the Philippines and killed more than 1000 residents. Minimum Arctic sea ice extent in September and Northern Hemisphere snow cover extent in June both reached new record lows. June snow cover extent is now declining at a faster rate (-17.6% per decade) than September sea ice extent (-13.0% per decade). Permafrost temperatures reached record high values in northernmost Alaska. A new melt extent record occurred on 11-12 July on the Greenland ice sheet; 97% of the ice sheet showed some form of melt, four times greater than the average melt for this time of year. The climate in Antarctica was relatively stable overall. The largest maximum sea ice extent since records begain in 1978 was observed in September 2012. In the stratosphere, warm air led to the second smallest ozone hole in the past two decades. Even so, the springtime ozone layer above Antarctica likely will not return to its early 1980s state until about 2060. Following a slight decline associated with the global 2 emissions from fossil fuel combustion and cement production reached a record 9.5 +/- 0.5 Pg C in 2011 and a new record of 9.7 +/- 0.5 Pg C is estimated for 2012. Atmospheric CO2 concentrations increased by 2.1 ppm in 2012, to 392.6 ppm. In spring 2012, 2 concentration exceeded 400 ppm at 7 of the 13 Arctic observation sites. Globally, other greenhouse gases including methane and nitrous oxide also continued to rise in concentration and the combined effect now represents a 32% increase in radiative forcing over a 1990 baseline. Concentrations of most ozone depleting substances continued to fall.
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6. |
- 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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- Luo, Yang, et al.
(författare)
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Three-dimensional and temperature-dependent electronic structure of the heavy-fermion compound CePt2In7 studied by angle-resolved photoemission spectroscopy
- 2020
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 101:11
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Tidskriftsartikel (refereegranskat)abstract
- The three-dimensional and temperature-dependent electronic structures of the heavy-fermion superconductor CePt2In7 are investigated. Angle-resolved photoemission spectroscopy using variable photon energy establishes the existence of quasi-two- and three-dimensional Fermi surface topologies. Temperature-dependent 4d-4f on-resonance photoemission spectroscopies data reveal that heavy quasiparticle bands begin to form at a temperature well above the characteristic (coherence) temperature T+. The emergence of low-lying crystal electric field excitation may be responsible for the "relocalization" or the precursor to the establishment of heavy electrons coherence in heavy-fermion compounds. These findings provide critical insight into understanding the hybridization in heavy-fermion systems.
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- Song, Jiao-Jiao, et al.
(författare)
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The 4f-Hybridization Strength in CemMnIn3m+2n Heavy-Fermion Compounds Studied by Angle-Resolved Photoemission Spectroscopy
- 2021
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Ingår i: Chinese Physics Letters. - : IOP Publishing. - 0256-307X .- 1741-3540. ; 38:10
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Tidskriftsartikel (refereegranskat)abstract
- We systemically investigate the nature of Ce 4f electrons in structurally layered heavy-fermion compounds CemMnIn3m+2n (with M = Co, Rh, Jr, and Pt, m = 1, 2, n = 0-2), at low temperature using on-resonance angle-resolved photoemission spectroscopy. Three heavy quasiparticle bands f(0), f(7/2)(1) and f(5/2)(1), are observed in all compounds, whereas their intensities and energy locations vary greatly with materials. The strong f(0) states imply that the localized electron behavior dominates the Ce 4f states. The Ce 4f electrons are partially hybridized with the conduction electrons, making them have the dual nature of localization and itinerancy. Our quantitative comparison reveals that the f(5/2)(1)-f (0) intensity ratio is more suitable to reflect the 4f-state hybridization strength.
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9. |
- Wang, Fang, et al.
(författare)
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Emerging contaminants: A One Health perspective
- 2024
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Ingår i: Innovation. - 2666-6758. ; 5
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Forskningsöversikt (refereegranskat)abstract
- Environmental pollution is escalating due to rapid global development that often prioritizes human needs over planetary health. Despite global efforts to mitigate legacy pollutants, the continuous introduction of new substances remains a major threat to both people and the planet. In response, global initiatives are focusing on risk assessment and regulation of emerging contaminants, as demonstrated by the ongoing efforts to establish the UN's Intergovernmental Science-Policy Panel on Chemicals, Waste, and Pollution Prevention. This review identifies the sources and impacts of emerging contaminants on planetary health, emphasizing the importance of adopting a One Health approach. Strategies for monitoring and addressing these pollutants are discussed, underscoring the need for robust and socially equitable environmental policies at both regional and international levels. Urgent actions are needed to transition toward sustainable pollution management practices to safeguard our planet for future generations.
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10. |
- Bravo, L, et al.
(författare)
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- 2021
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swepub:Mat__t
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11. |
- Tabiri, S, et al.
(författare)
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- 2021
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swepub:Mat__t
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12. |
- Luo, Zhixun, et al.
(författare)
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Stabilizing single-molecular Raman spectrum of a nonbonding molecule on Ag nanoparticles
- 2009
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; :11, s. 1342-1344
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The applicability of single-molecule surface-enhanced Raman spectroscopy to a nonbonding molecular system is demonstrated on a uniformly assembled colloidal Ag nanoparticle substrate.
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13. |
- Qiao, Xi Min, et al.
(författare)
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Re-positive Cases of Nucleic Acid Tests in Discharged Patients With COVID-19 : A Follow-Up Study
- 2020
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Ingår i: Frontiers in Medicine. - : Frontiers Media SA. - 2296-858X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: The frequent emergence of the re-positive patients with COVID-19 is a potential threat worldwide. This study aimed to describe data from admission to follow-up for patients with COVID-19 and analyze the possible causes for re-positive nucleic acid tests to provide more scientific basis for reducing the numbers of re-positive patients after discharge. Methods: We retrospectively recorded 15 patients with COVID-19 admitted to the Xianyang Central Hospital, China. The baseline, exposure histories, clinical syndromes, laboratory characteristics, nucleic acid, and follow-up tests were analyzed, and the radiological characteristics of re-positive patient at different periods were compared. Results: Eight (53.33%) patients had the history of travel to Wuhan, four (26.67%) patients had close contact with confirmed patients, and one (6.67%) patient had close contact with suspected patients. After treatment, all patients had two consecutively negative nucleic acid tests and were discharged from hospital. All patients were followed up for more than 14 days, and the average time from discharge to the first follow-up was 14.67 ± 3.31 days (from 9 to 22 days). Most patients showed no clinical symptoms and negative nucleic acid tests, while one patient had an itchy throat, her CT scan showed a light density shadow in the right lower lobe of the lung, and the nucleic acid was once again positive. The second follow-up of the other 14 patients (except the re-positive one) was conducted 20.80 ± 7.78 days (from 13 to 30 days) after discharge, and all of them had negative nucleic acid tests. The positive patient was immediately readmitted and received a new round of treatment. Her family members and colleagues remained healthy until now. Conclusions: The quality of nucleic acid testing reagents should be enhanced, and the training of nucleic acid sampling operators should be strengthened to reduce the false-negative results in the nucleic acid of SARS-CoV-2; the clinical specimens of throat and nasopharynx swabs can be collected at the same time; IgM- and IgG-specific antibodies of SARS-CoV-2 should be carried out for discharged patients; the radiological characteristics should be evaluated strictly; and the discharge standard can be specified according to the baseline and severity of disease of patients.
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15. |
- Guo, Ying, et al.
(författare)
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A Complex Structural Variation on Chromosome 27 Leads to the Ectopic Expression of HOXB8 and the Muffs and Beard Phenotype in Chickens
- 2016
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 12:6
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Tidskriftsartikel (refereegranskat)abstract
- Muffs and beard (Mb) is a phenotype in chickens where groups of elongated feathers gather from both sides of the face (muffs) and below the beak (beard). It is an autosomal, incomplete dominant phenotype encoded by the Muffs and beard (Mb) locus. Here we use genome-wide association (GWA) analysis, linkage analysis, Identity-by-Descent (IBD) mapping, array-CGH, genome re-sequencing and expression analysis to show that the Mb allele causing the Mb phenotype is a derived allele where a complex structural variation (SV) on GGA27 leads to an altered expression of the gene HOXB8. This Mb allele was shown to be completely associated with the Mb phenotype in nine other independent Mb chicken breeds. The Mb allele differs from the wild-type mb allele by three duplications, one in tandem and two that are translocated to that of the tandem repeat around 1.70 Mb on GGA27. The duplications contain total seven annotated genes and their expression was tested during distinct stages of Mb morphogenesis. A continuous high ectopic expression of HOXB8 was found in the facial skin of Mb chickens, strongly suggesting that HOXB8 directs this regional feather-development. In conclusion, our results provide an interesting example of how genomic structural rearrangements alter the regulation of genes leading to novel phenotypes. Further, it again illustrates the value of utilizing derived phenotypes in domestic animals to dissect the genetic basis of developmental traits, herein providing novel insights into the likely role of HOXB8 in feather development and differentiation.
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16. |
- Jiang, Kang, et al.
(författare)
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Single platinum atoms embedded in nanoporous cobalt selenide as electrocatalyst for accelerating hydrogen evolution reaction
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- Designing efficient electrocatalysts for hydrogen evolution reaction is significant for renewable and sustainable energy conversion. Here, we report single-atom platinum decorated nanoporous Co0.85Se (Pt/np-Co0.85Se) as efficient electrocatalysts for hydrogen evolution. The achieved Pt/np-Co0.85Se shows high catalytic performance with a near-zero onset overpotential, a low Tafel slope of 35 mV dec(-1), and a high turnover frequency of 3.93 s(-1) at -100 mV in neutral media, outperforming commercial Pt/C catalyst and other reported transition-metal-based compounds. Operando X-ray absorption spectroscopy studies combined with density functional theory calculations indicate that single-atom platinum in Pt/np-Co0.85Se not only can optimize surface states of Co0.85Se active centers under realistic working conditions, but also can significantly reduce energy barriers of water dissociation and improve adsorption/desorption behavior of hydrogen, which synergistically promote thermodynamics and kinetics. This work opens up further opportunities for local electronic structures tuning of electrocatalysts to effectively manipulate its catalytic properties by an atomic-level engineering strategy.
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17. |
- Luo, Xingbing, et al.
(författare)
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On the Character and Model of Distribution of Mathematics History in the High School Mathematics Textbook : Based on the Analysis of the Mathematics Compulsory Textbook Published by Beijing Normal University Press
- 2012
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Ingår i: Journal of Mathematics Education. - 1004-9894. ; 21:1, s. 30-33
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Tidskriftsartikel (refereegranskat)abstract
- In the high school mathematical compulsory text books published by the Beijing Normal University Press, the knowledge on the history of mathematics occurs in 22 places. Among which, about 63.64% is in the form of reading materials. The contents about history of mathematics are focused on the stories of mathematicians, famous mathematical problems and other materials relative to the history of mathematics, and they were mainly represented in text forms. There are two designing models for integrating the history of mathematics into mathematics teaching, that is, explicit integration and implicit integration. The former includes two ways, one is deriving the history of mathematics from mathematical knowledge and the other is deriving the mathematical knowledge from the history of mathematics.
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18. |
- Wang, Min, et al.
(författare)
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Apolipoprotein M induces inhibition of inflammatory responses via the S1PR1 and DHCR24 pathways
- 2019
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Ingår i: Molecular Medicine Reports. - 1791-2997. ; 19:2, s. 1272-1283
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Tidskriftsartikel (refereegranskat)abstract
- © 2019 Spandidos Publications. All rights reserved. Apolipoprotein M (ApoM) is a type of apolipoprotein. It is well known that high-density lipoprotein (HDL) decreases inflammatory responses via the apoM-sphingosine-1-phosphate (S1P) pathway. The present study further investigated the importance of ApoM in the inhibitory effects of HDL on inflammation. Mice with an apoM gene deficiency (apoM-/-) were employed to investigate the effects of ApoM on the expression of interleukin-1β (IL-1β), monocyte chemotactic protein-1 (MCP-1), S1P receptor-1 (S1PR1) and 3β-hydroxysterol Δ-24-reductase (DHCR24), as compared with in wild-type mice (apoM+/+). Furthermore, cell culture experiments were performed using a permanent human hybrid endothelial cell line (EA.hy926). Cells were cultured in the presence of recombinant human apoM (rec-apoM) or were induced to overexpress apoM (apoMTg); subsequently, cells were treated with tumor necrosis factor-α (TNF-α), in order to investigate the effects of ApoM on IL-1β and MCP-1. The results demonstrated that the mRNA expression levels of IL-1β and MCP-1 were significantly higher in the liver following administration of lipopolysaccharide in apoM-/- mice compared with in apoM+/+ mice. In cell culture experiments, when cells were pre-cultured with rec-apoM or were engineered to overexpress apoM (apoMTg), they exhibited decreased expression levels of IL-1β and MCP-1 following TNF-α treatment compared with in normal apoM-expressing cells (apoMTgN). Furthermore, the mRNA expression levels of IL-1β and MCP-1 were significantly elevated following addition of the S1PR1 inhibitor W146, but not by the scavenger receptor class B type I inhibitor, block lipid transport-1 (BLT-1), in apoMTg cells prior to TNF-α treatment. Conversely, there were no differences in these inflammatory biomarkers under the same conditions in apoMTgN cells. The mRNA expression levels of DHCR24 were significantly reduced by the addition of BLT-1 prior to TNF-α treatment in apoMTg cells; however, there was no difference in the expression of this inflammatory biomarker in apoMTgN cells. In conclusion, ApoM displayed inhibitory effects against the inflammatory response in vivo and in vitro; these effects may be induced via the S1PR1 and DHCR24 pathways.
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19. |
- Wang, Xiaoyu, et al.
(författare)
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Guest Editorial: Modeling and Simulation Methods for Analysis and Design of Advanced Energy Conversion Systems
- 2020
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Ingår i: IEEE Transactions on Energy Conversion. - 1558-0059 .- 0885-8969. ; 35:1, s. 309-311
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The papers in this special section examine modeling and simulation methods for the analysis and design of advanced energy conversion systems. Energy conversion lies aEnergyveral fronts including materials, conversion methods, power electronics, and controls have created new opportunities for efficient energy conversion from both the conventional and new sources of energy. Our urgent need to solve many critical problems with regards to the sustainability and security of our energy system as well as the ever-increasing environmental challenges facing humanity have further spurred unprecedented opportunities for creation of innovative solutions to address these challenges.
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20. |
- Xiao, Kai, et al.
(författare)
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Photoelectrical characteristics of a C/CNx multiwalled nanotube
- 2007
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Ingår i: Advanced Functional Materials. - : Wiley. - 1616-301X .- 1616-3028. ; 17:15, s. 2842-2846
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Tidskriftsartikel (refereegranskat)abstract
- A nanotube diode fabricated from a single C/CNx multiwalled nanotube exhibits a large photocurrent and a large photovoltage under illumination. The current-voltage (I-V) characteristics of the diode indicate a clear rectification effect. By comparing the I-V characteristics of C, CNx, and C/CNx nanotube diodes, we show that the rectifying characteristics of the C/CNx diode arises from the molecular junction formed at the C/CNx interface where the C and CNx segments are chemically bonded. External radiation photochernically generates electrons and holes in the C/CNx nanotube, producing a large photocurrent because of the influence of the strong electric field in the vicinity of the C/CNx junction. These unique photoresponsive characteristics of C/CNx, nanotube junction diodes points to potential applications such as photovoltaic devices and photodiodes.
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- Xiong, Wenjuan, et al.
(författare)
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SiNx films and membranes for photonic and MEMS applications
- 2020
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Ingår i: Journal of materials science. Materials in electronics. - : Springer Science and Business Media LLC. - 0957-4522 .- 1573-482X. ; 31, s. 90-97
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a novel process to form SiN x films and process for membranes with excellent mechanical properties for micro-electro-mechanical systems application as well as integration as IR waveguide for photonic application. The SiN x films were fabricated in SiNgen apparatus which is a single wafer chamber equipment compared to conventional low pressure chemical vapor deposition furnace process. The films showed low stress, good mechanical properties, but the synthesis also eradicates the issues of particle contamination. Through optimizing of the growth parameters and post annealing profile, low stress (40 Mpa) SiN x film could be finally deposited when annealing temperature rose up to 1150 °C. The stress relaxation is a result of more Si nano-crystalline which was formed during annealing, according to the FTIR results. The mechanical properties, Young’s modulus and hardness, were 210 Gpa and 20 Gpa respectively. For the waveguide application, a stack of three layers, SiO 2 /SiN x /SiO 2 was formed where the optimized layer thicknesses were used for minimum optical loss according to simulation feedback. After deposition of the first two layers in the stack, the samples were annealed in range of 900–1150 °C in order to release the stress. Chemical mechanical polish technique was applied to planarize the nitride layer prior to the oxide cladding layer. Such wafers can be used to bond to Si or Ge to manufacture advanced substrates.
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22. |
- Zhang, Shuangshuang, et al.
(författare)
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Narrow-gap, semiconducting, superhard amorphous carbon with high toughness, derived from C60 fullerene
- 2021
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Ingår i: Cell Reports Physical Science. - : Elsevier. - 2666-3864. ; 2:9
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Tidskriftsartikel (refereegranskat)abstract
- New carbon forms that exhibit extraordinary physicochemical properties can be generated from nanostructured precursors under extreme pressure. Nevertheless, synthesis of such fascinating materials is often not well understood. That is the case of the C60 precursor, with irreproducible results that impede further progress in the materials design. Here, the semiconducting amorphous carbon, having band gaps of 0.1–0.3 eV and the advantages of isotropic superhardness and superior toughness over single-crystal diamond and inorganic glasses, is produced from fullerene at high pressure and moderate temperatures. A systematic investigation of the structure and bonding evolution is carried out with complementary characterization methods, which helps to build a model of the transformation that can be used in further high-pressure/high-temperature (high p,T) synthesis of novel nano-carbon systems for advanced applications. The amorphous carbon materials produced have the potential of accomplishing the demanding optoelectronic applications that diamond and graphene cannot achieve.
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23. |
- Zhao, Haifeng, et al.
(författare)
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High-Brightness Perovskite Light-Emitting Diodes Based on FAPbBr(3) Nanocrystals with Rationally Designed Aromatic Ligands
- 2021
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Ingår i: ACS Energy Letters. - : AMER CHEMICAL SOC. - 2380-8195. ; 6:7, s. 2395-2403
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Tidskriftsartikel (refereegranskat)abstract
- Despite rapid developments of light-emitting diodes (LEDs) based on emerging perovskite nanocrystals (PeNCs), it remains challenging to achieve devices with integrated high efficiencies and high brightness because of the insulating long-chain ligands used for the PeNCs. Herein, we develop highly luminescent and stable formamidinium lead bromide PeNCs capped with rationally designed short aromatic ligands of 2-naphthalenesulfonic acid (NSA) for LEDs. Compared with commonly used oleic acid ligands, the NSA molecules not only preserve the surface properties of the PeNCs during the purification but also notably improve the electrical properties of the assembled emissive layers, ensuring efficient charge injection/transport in the devices. The resulting champion LED with electroluminescence approaching the Rec. 2020 green primary color demonstrates a high brightness of 67 115 cd cm(-2) and a peak external quantum efficiency of 19.2%. More impressively, the device shows negligibly decreased efficiency at an elevated brightness of 20 000 cd cm(-2) and a well-retained efficiency of over 10% at around 65 000 cd cm(-2), presenting a breakthrough in LEDs based on PeNCs.
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