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Sökning: WFRF:(Li Xiaojun)

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1.
  • Kristan, Matej, et al. (författare)
  • The first visual object tracking segmentation VOTS2023 challenge results
  • 2023
  • Ingår i: 2023 IEEE/CVF International conference on computer vision workshops (ICCVW). - : Institute of Electrical and Electronics Engineers Inc.. - 9798350307443 - 9798350307450 ; , s. 1788-1810
  • Konferensbidrag (refereegranskat)abstract
    • The Visual Object Tracking Segmentation VOTS2023 challenge is the eleventh annual tracker benchmarking activity of the VOT initiative. This challenge is the first to merge short-term and long-term as well as single-target and multiple-target tracking with segmentation masks as the only target location specification. A new dataset was created; the ground truth has been withheld to prevent overfitting. New performance measures and evaluation protocols have been created along with a new toolkit and an evaluation server. Results of the presented 47 trackers indicate that modern tracking frameworks are well-suited to deal with convergence of short-term and long-term tracking and that multiple and single target tracking can be considered a single problem. A leaderboard, with participating trackers details, the source code, the datasets, and the evaluation kit are publicly available at the challenge website1
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2.
  • Liu, Tao, et al. (författare)
  • 16% efficiency all-polymer organic solar cells enabled by a finely tuned morphology via the design of ternary blend
  • 2021
  • Ingår i: Joule. - : CELL PRESS. - 2542-4351. ; 5:4, s. 914-930
  • Tidskriftsartikel (refereegranskat)abstract
    • A SUMMARY There is an urgent demand for all-polymer organic solar cells (AP-OSCs) to gain higher efficiency. Here, we successfully improve the performance to 16.09% by introducing a small amount of BN-T, a B <- N-type polymer acceptor, into the PM6:PY-IT blend. It has been found that BN-T makes the active layer, based on the PM6:PY-IT:BN-T ternary blend, more crystalline but meanwhile slightly reduces the phase separation, leading to enhancement of both exciton harvesting and charge transport. From a thermodynamic viewpoint, BN-T prefers to reside between PM6 and PY-IT, and the fraction of this fine-tunes the morphology. Besides, a significantly reduced nonradiative energy loss occurs in the ternary blend, along with the coexistence of energy and charge transfer between the two acceptors. The progressive performance facilitated by these improved properties demonstrates that AP-OSCs can possibly comparably efficient with those based on small molecule acceptors, further enhancing the competitiveness of this device type.
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3.
  • Davies, Stuart J., et al. (författare)
  • ForestGEO: Understanding forest diversity and dynamics through a global observatory network
  • 2021
  • Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 253
  • Tidskriftsartikel (refereegranskat)abstract
    • ForestGEO is a network of scientists and long-term forest dynamics plots (FDPs) spanning the Earth's major forest types. ForestGEO's mission is to advance understanding of the diversity and dynamics of forests and to strengthen global capacity for forest science research. ForestGEO is unique among forest plot networks in its large-scale plot dimensions, censusing of all stems ≥1 cm in diameter, inclusion of tropical, temperate and boreal forests, and investigation of additional biotic (e.g., arthropods) and abiotic (e.g., soils) drivers, which together provide a holistic view of forest functioning. The 71 FDPs in 27 countries include approximately 7.33 million living trees and about 12,000 species, representing 20% of the world's known tree diversity. With >1300 published papers, ForestGEO researchers have made significant contributions in two fundamental areas: species coexistence and diversity, and ecosystem functioning. Specifically, defining the major biotic and abiotic controls on the distribution and coexistence of species and functional types and on variation in species' demography has led to improved understanding of how the multiple dimensions of forest diversity are structured across space and time and how this diversity relates to the processes controlling the role of forests in the Earth system. Nevertheless, knowledge gaps remain that impede our ability to predict how forest diversity and function will respond to climate change and other stressors. Meeting these global research challenges requires major advances in standardizing taxonomy of tropical species, resolving the main drivers of forest dynamics, and integrating plot-based ground and remote sensing observations to scale up estimates of forest diversity and function, coupled with improved predictive models. However, they cannot be met without greater financial commitment to sustain the long-term research of ForestGEO and other forest plot networks, greatly expanded scientific capacity across the world's forested nations, and increased collaboration and integration among research networks and disciplines addressing forest science.
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4.
  • Zhang, Kaicheng, et al. (författare)
  • SN 2014J in M82 : new insights on the spectral diversity of Type Ia supernovae
  • 2018
  • Ingår i: Monthly notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 0035-8711 .- 1365-2966. ; 481:1, s. 878-893
  • Tidskriftsartikel (refereegranskat)abstract
    • We present extensive spectroscopic observations for one of the closest Type Ia supernovae (SNe Ia), SN 2014J discovered in M82, ranging from 10.4 d before to 473.2 d after B-band maximum light. The diffuse interstellar band features detected in a high-resolution spectrum allow an estimate of line-of-sight extinction as A(v) similar to 1.9 +/- 0.6 mag. Spectroscopically, SN 2014J can be put into the high-velocity (HV) subgroup in Wang's classification with a velocity of Si II lambda 6355 at maximum light of upsilon(0) = 1.22 +/- 0.01 x 10(4) km s(-1) but has a low velocity gradient (LVG, following Benetti's classification) of (v) over bar = 41 +/- 2 km s(-1) d(-1), which is inconsistent with the trend that HV SNe Ia generally have larger velocity gradients. We find that the HV SNe Ia with LVGs tend to have relatively stronger Si III (at similar to 4400 angstrom) absorptions in early spectra, larger ratios of S II lambda 5468 to S II lambda 5640, and weaker Si II 5972 absorptions compared to their counterparts with similar velocities but high velocity gradients. This shows that the HV+ LVG subgroup of SNe Ia may have intrinsically higher photospheric temperature, which indicates that their progenitors may experience more complete burning in the explosions relative to the typical HV SNe Ia.
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5.
  • He, Lei, et al. (författare)
  • Non-symmetric responses of leaf onset date to natural warming and cooling in northern ecosystems
  • 2023
  • Ingår i: PNAS Nexus. - 2752-6542. ; 2:9
  • Tidskriftsartikel (refereegranskat)abstract
    • The northern hemisphere has experienced regional cooling, especially during the global warming hiatus (1998-2012) due to ocean energy redistribution. However, the lack of studies about the natural cooling effects hampers our understanding of vegetation responses to climate change. Using 15,125 ground phenological time series at 3,620 sites since the 1950s and 31-year satellite greenness observations (1982-2012) covering the warming hiatus period, we show a stronger response of leaf onset date (LOD) to natural cooling than to warming, i.e. the delay of LOD caused by 1°C cooling is larger than the advance of LOD with 1°C warming. This might be because cooling leads to larger chilling accumulation and heating requirements for leaf onset, but this non-symmetric LOD response is partially offset by warming-related drying. Moreover, spring greening magnitude, in terms of satellite-based greenness and productivity, is more sensitive to LOD changes in the warming area than in the cooling. These results highlight the importance of considering non-symmetric responses of spring greening to warming and cooling when predicting vegetation-climate feedbacks.
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6.
  • Jia, Zhenrong, et al. (författare)
  • Near-infrared absorbing acceptor with suppressed triplet exciton generation enabling high performance tandem organic solar cells
  • 2023
  • Ingår i: Nature Communications. - : NATURE PORTFOLIO. - 2041-1723. ; 14:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Reducing the energy loss of sub-cells is critical for high performance tandem organic solar cells, while it is limited by the severe non-radiative voltage loss via the formation of non-emissive triplet excitons. Herein, we develop an ultra-narrow bandgap acceptor BTPSeV-4F through replacement of terminal thiophene by selenophene in the central fused ring of BTPSV-4F, for constructing efficient tandem organic solar cells. The selenophene substitution further decrease the optical bandgap of BTPSV-4F to 1.17 eV and suppress the formation of triplet exciton in the BTPSV-4F-based devices. The organic solar cells with BTPSeV-4F as acceptor demonstrate a higher power conversion efficiency of 14.2% with a record high short-circuit current density of 30.1 mA cm(-2) and low energy loss of 0.55 eV benefitted from the low non-radiative energy loss due to the suppression of triplet exciton formation. We also develop a high-performance medium bandgap acceptor O1-Br for front cells. By integrating the PM6:O1-Br based front cells with the PTB7-Th:BTPSeV-4F based rear cells, the tandem organic solar cell demonstrates a power conversion efficiency of 19%. The results indicate that the suppression of triplet excitons formation in the near-infrared-absorbing acceptor by molecular design is an effective way to improve the photovoltaic performance of the tandem organic solar cells. Reducing energy loss of sub-cells is critical for high performance tandem organic solar cells. Here, the authors design and synthesize an ultra-narrow bandgap acceptor through replacement of terminal thiophene by selenophene in the central fused ring, achieving efficiency of 19% for tandem cells.
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7.
  • Li, Xinxi, et al. (författare)
  • Increasing importance of precipitation in spring phenology with decreasing latitudes in subtropical forest area in China
  • 2021
  • Ingår i: Agricultural and Forest Meteorology. - : Elsevier BV. - 0168-1923. ; 304-305
  • Tidskriftsartikel (refereegranskat)abstract
    • Climate warming has significantly advanced plant spring phenology in temperate and boreal biomes in the northern hemisphere. However, the response of subtropical forest phenology to climate change remains largely unclear. This study aimed to determine the spatiotemporal patterns of spring photosynthetic phenology in subtropical forests in China over the period 2002-2017 and explore its underlying mechanism in response to the changes of different climate variables. We applied four methods to extract the start of the photosynthetic period (SOP) from a solar–induced chlorophyll fluorescence (SIF) data set during the period 2002 to 2017, and determined correlations between SOP and environmental factors using partial correlation analyses. Overall, the SOP was advanced by 6.8 days. Furthermore, we found that the SIF-based SOP is highly correlated with the flux data–based photosynthetic onset dates, demonstrating that SIF can be a useful index in characterizing the photosynthetic phenology in subtropical forests. Interestingly, based on partial correlation analysation temperature dominated the SOP in the northern subtropical forest, but the importance of precipitation increased with decreasing latitudes, and the primary climatic control of SOP in southern monsoon evergreen forests is precipitation. These results suggested that the predicted increase in temperature and shift in precipitation regimes under ongoing climate change might potentially largely affect the photosynthetic phenology, and thus affect the carbon and water cycles in subtropical forests.
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8.
  • Luo, Yifei, et al. (författare)
  • Technology Roadmap for Flexible Sensors
  • 2023
  • Ingår i: ACS Nano. - : American Chemical Society. - 1936-0851 .- 1936-086X. ; 17:6, s. 5211-5295
  • Forskningsöversikt (refereegranskat)abstract
    • Humans rely increasingly on sensors to address grand challenges and to improve quality of life in the era of digitalization and big data. For ubiquitous sensing, flexible sensors are developed to overcome the limitations of conventional rigid counterparts. Despite rapid advancement in bench-side research over the last decade, the market adoption of flexible sensors remains limited. To ease and to expedite their deployment, here, we identify bottlenecks hindering the maturation of flexible sensors and propose promising solutions. We first analyze challenges in achieving satisfactory sensing performance for real-world applications and then summarize issues in compatible sensor-biology interfaces, followed by brief discussions on powering and connecting sensor networks. Issues en route to commercialization and for sustainable growth of the sector are also analyzed, highlighting environmental concerns and emphasizing nontechnical issues such as business, regulatory, and ethical considerations. Additionally, we look at future intelligent flexible sensors. In proposing a comprehensive roadmap, we hope to steer research efforts towards common goals and to guide coordinated development strategies from disparate communities. Through such collaborative efforts, scientific breakthroughs can be made sooner and capitalized for the betterment of humanity.
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9.
  • Wang, Guangwei, et al. (författare)
  • Co-hydrothermal carbonization of polyvinyl chloride and pyrolysis carbon black for the preparation of clean solid fuels
  • 2024
  • Ingår i: Fuel. - : Elsevier BV. - 0016-2361 .- 1873-7153. ; 361
  • Tidskriftsartikel (refereegranskat)abstract
    • Large quantities of polyvinyl chloride (PVC) and waste tires generated daily have the disadvantage of high content of harmful elements. They cannot be directly applied to blast furnace ironmaking. In this study, Cl in PVC and Zn in pyrolysis products of waste tires (pyrolysis carbon black, CB) were effectively removed by co-hydrothermal carbonization (co-HTC). The results indicated the dechlorination and dezincification efficiencies of co-HTC were improved by 2.78 % and 64.69 %, respectively, compared to HTC. Compositional analysis shows that the ash content of co-HTC is reduced by at least 7.67 % compared to conventional HTC. The hydrochar produced by co-HTC has an higher heating value (HHV) ranging from 30.67 to 34.13 MJ/kg. Results of physical and chemical characteristics analysis showed increasing the proportion of CB can reduce the C–H and -CHCl- functional groups and improve the carbon orderliness of the hydrochar. Combustion characteristics and kinetic analyses show that the combustibility of hydrochar increases with an increase in the proportion of PVC added to the co-HTC. The thermal stability and activation energy of the hydrochar increase with the addition of CB. Overall, this study has removed major harmful elements from PVC and CB through co-HTC, converting both into high-quality solid fuels that can be utilised in blast furnace ironmaking.
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10.
  • Wang, Guangwei, et al. (författare)
  • Preparation of Biomass Hydrochar and Application Analysis of Blast Furnace Injection
  • 2023
  • Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 16:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrothermal carbonization (HTC) technology was used to carbonize and improve biomass raw material to obtain hydrochar. The effects of HTC temperature and holding time on the yield, composition, structure, combustion behavior, and safety of hydrochar were studied systematically. In addition, the results show that with the increase in HTC temperature and the prolongation of holding time, the yield of hydrochar gradually reduces, the fixed carbon content of hydrochar increases, the volatile content decreases, and a large number of ash and alkali metals enter the liquid phase and are removed. Further, the analysis of the combustion properties and the structure of hydrochar can be observed in that, as the HTC process promotes the occurrence of polymerization reactions, the specific surface area gradually reduces, the degree of carbon ordering increases, and the combustion curve moves toward the high-temperature zone and gradually approaches bituminous coal. Since biomass hydrochar has the characteristic of being carbon neutral, blast furnace injection hydrochar can reduce CO2 emissions, and every 1 kg/tHM of biomass hydrochar can reduce CO2 emissions by 1.95 kg/tHM.
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11.
  • Azevedo, Flavio, et al. (författare)
  • Social and moral psychology of COVID-19 across 69 countries
  • 2023
  • Ingår i: Scientific Data. - : NATURE PORTFOLIO. - 2052-4463. ; 10:1
  • Tidskriftsartikel (refereegranskat)abstract
    • The COVID-19 pandemic has affected all domains of human life, including the economic and social fabric of societies. One of the central strategies for managing public health throughout the pandemic has been through persuasive messaging and collective behaviour change. To help scholars better understand the social and moral psychology behind public health behaviour, we present a dataset comprising of 51,404 individuals from 69 countries. This dataset was collected for the International Collaboration on Social & Moral Psychology of COVID-19 project (ICSMP COVID-19). This social science survey invited participants around the world to complete a series of moral and psychological measures and public health attitudes about COVID-19 during an early phase of the COVID-19 pandemic (between April and June 2020). The survey included seven broad categories of questions: COVID-19 beliefs and compliance behaviours; identity and social attitudes; ideology; health and well-being; moral beliefs and motivation; personality traits; and demographic variables. We report both raw and cleaned data, along with all survey materials, data visualisations, and psychometric evaluations of key variables.
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12.
  • Chen, Shouzhi, et al. (författare)
  • Informing the SWAT model with remote sensing detected vegetation phenology for improved modeling of ecohydrological processes
  • 2023
  • Ingår i: Journal of Hydrology. - : Elsevier BV. - 0022-1694. ; 616
  • Tidskriftsartikel (refereegranskat)abstract
    • The Soil and Water Assessment Tool (SWAT) model has been widely applied for simulating the water cycle and quantifying the influence of climate change and anthropogenic activities on hydrological processes. A major uncertainty of SWAT stems from the poor representation of vegetation dynamics due to the use of a simplistic vegetation growth and development module. Using long-term remote sensing-based phenological data, the SWAT model's vegetation module was improved by adding a dynamic growth start date and the dynamic heat requirement for vegetation growth rather than using constant values. The new SWAT model was verified in the Han River basin, China, and found its performance was much improved in comparison with that of the original SWAT model. Specifically, the accuracy of the leaf area index (LAI) simulation improved notably (coefficient of determination (R2) increased by 0.193, Nash–Sutcliffe Efficiency (NSE) increased by 0.846, and percent bias decreased by 42.18 %), and that of runoff simulation improved modestly (R2 increased by 0.05 and NSE was similar). Additionally, it is found that the original SWAT model substantially underestimated evapotranspiration (Penman-Monteith method) in comparison with the new SWAT model (65.09 mm (or 22.17 %) for forests, 92.27 mm (or 32 %) for orchards, and 96.16 mm (or 36.4 %) for farmland), primarily due to the inaccurate representation of LAI dynamics. Our results suggest that an accurate representation of phenological dates in the vegetation growth module is important for improving the SWAT model performance in terms of estimating terrestrial water and energy balance.
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13.
  • Ding, Li, et al. (författare)
  • Somatic mutations affect key pathways in lung adenocarcinoma
  • 2008
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 455:7216, s. 1069-1075
  • Tidskriftsartikel (refereegranskat)abstract
    • Determining the genetic basis of cancer requires comprehensive analyses of large collections of histopathologically well-classified primary tumours. Here we report the results of a collaborative study to discover somatic mutations in 188 human lung adenocarcinomas. DNA sequencing of 623 genes with known or potential relationships to cancer revealed more than 1,000 somatic mutations across the samples. Our analysis identified 26 genes that are mutated at significantly high frequencies and thus are probably involved in carcinogenesis. The frequently mutated genes include tyrosine kinases, among them the EGFR homologue ERBB4; multiple ephrin receptor genes, notably EPHA3; vascular endothelial growth factor receptor KDR; and NTRK genes. These data provide evidence of somatic mutations in primary lung adenocarcinoma for several tumour suppressor genes involved in other cancers--including NF1, APC, RB1 and ATM--and for sequence changes in PTPRD as well as the frequently deleted gene LRP1B. The observed mutational profiles correlate with clinical features, smoking status and DNA repair defects. These results are reinforced by data integration including single nucleotide polymorphism array and gene expression array. Our findings shed further light on several important signalling pathways involved in lung adenocarcinoma, and suggest new molecular targets for treatment.
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14.
  • Foo, Kylie S, et al. (författare)
  • Human ISL1+ ventricular progenitors self-assemble into an in vivo functional heart patch and preserve cardiac function post infarction
  • 2018
  • Ingår i: Molecular Therapy. - Stockholm : Karolinska Institutet, Dept of Cell and Molecular Biology. - 1525-0016. ; 26:7, s. 1644-1659
  • Tidskriftsartikel (refereegranskat)abstract
    • The generation of human pluripotent stem cell (hPSC)-derived ventricular progenitors and their assembly into a 3-dimensional in vivo functional ventricular heart patch has remained an elusive goal. Herein, we report the generation of an enriched pool of hPSC-derived ventricular progenitors (HVPs), which can expand, differentiate, self-assemble, and mature into a functional ventricular patch in vivo without the aid of any gel or matrix. We documented a specific temporal window, in which the HVPs will engraft in vivo. On day 6 of differentiation, HVPs were enriched by depleting cells positive for pluripotency marker TRA-1-60 with magnetic-activated cell sorting (MACS), and 3 million sorted cells were sub-capsularly transplanted onto kidneys of NSG mice where, after 2 months, they formed a 7 mm x 3 mm x 4 mm myocardial patch resembling the ventricular wall. The graft acquired several features of maturation: expression of ventricular marker (MLC2v), desmosomes, appearance of T-tubule-like structures, and electrophysiological action potential signature consistent with maturation, all this in a non-cardiac environment. We further demonstrated that HVPs transplanted into un-injured hearts of NSG mice remain viable for up to 8 months. Moreover, transplantation of 2 million HVPs largely preserved myocardial contractile function following myocardial infarction. Taken together, our study reaffirms the promising idea of using progenitor cells for regenerative therapy. Correction in Mol Ther. 2021 Jan 6;29(1):409, DOI: 10.1016/j.ymthe.2020.11.015
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15.
  • Gao, Jingyu, et al. (författare)
  • Three-Dimensional Transient Electromagnetic Forward Modeling for Simulating Arbitrary Source Waveform Using Convolution Approach
  • 2023
  • Ingår i: IEEE Transactions on Geoscience and Remote Sensing. - : Institute of Electrical and Electronics Engineers Inc.. - 0196-2892 .- 1558-0644. ; 61
  • Tidskriftsartikel (refereegranskat)abstract
    • The transient electromagnetic (TEM) method utilizes artificial transmitters and measures electromagnetic (EM) responses to reveal the resistivity information of the subsurface. The current waveform of transmitters has nonnegligible effects on induced fields. Therefore, 3-D TEM forward modeling algorithms need the capability of simulating arbitrary waveforms to obtain accurate responses. In time-stepping-based 3-D TEM forward modeling, the source term (ST) approach is frequently used, which employs the source current density to model the waveform variation during time-stepping. The ST approach, however, requires fine-time discretization to describe complex waveforms, which could significantly raise the computational cost. We present a robust convolution (Conv) approach that computes the convolution between the time derivative of the waveform and the step-off response to incorporate the waveform effects in 3-D TEM modeling. The Conv approach does not discretize the waveform using time steps. Hence, it is advantageous when modeling full-waveform cases. The developed algorithm is based on the finite-element (FE) method using unstructured grids and the implicit backward Euler approach. Both galvanic and inductive transmitters are incorporated. Ground and airborne TEM surveys are tested using an actual airborne TEM waveform, a full waveform of the 2(n) -sequence pseudorandom signal, and various synthetic waveforms. Accuracy is validated against the 1-D and 3-D solutions of published studies. The ST and Conv approaches are compared. Synthetic examples show that the latter approach simplifies the waveform incorporation in TEM modeling and substantially improves time-stepping efficiency without sacrificing accuracy.
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16.
  • Li, Dong, et al. (författare)
  • Improve food retail supply chain operations with dynamic pricing and product tracing
  • 2006
  • Ingår i: International Journal of Services Operations and Informatics. - : InderScience Publishers. - 1741-539X .- 1741-5403. ; 1:4, s. 347-362
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper investigates the potential value adding capability of dynamic product tracing to the food supply chain management. As the environment of supply chain processes affect product quality significantly, technologies and approaches for tracking and tracing products have the potential to improve the food supply chain performance by dynamically identifying product quality situations. This can be achieved by tracing the product manufacturing and supply process with Automatic Product Identification (AutoID) technologies. An optimisation model has been developed to generate optimal pricing policies based on the dynamically identified product quality information. The research concluded that the dynamic identification of the product value (quality) would generate benefits to the food supply chain management with widely adopted optimal pricing approaches.
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17.
  • Li, Jian, et al. (författare)
  • Modulated structure determination and ion transport mechanism of oxide-ion conductor CeNbO4+δ
  • 2020
  • Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
  • Tidskriftsartikel (refereegranskat)abstract
    • CeNbO4+δ, a family of oxygen hyperstoichiometry materials with varying oxygen content (CeNbO4, CeNbO4.08, CeNbO4.25, CeNbO4.33) that shows mixed electronic and oxide ionic conduction, has been known for four decades. However, the oxide ionic transport mechanism has remained unclear due to the unknown atomic structures of CeNbO4.08 and CeNbO4.33. Here, we report the complex (3 + 1)D incommensurately modulated structure of CeNbO4.08, and the supercell structure of CeNbO4.33 from single nanocrystals by using a three-dimensional electron diffraction technique. Two oxide ion migration events are identified in CeNbO4.08 and CeNbO4.25 by molecular dynamics simulations, which was a synergic-cooperation knock-on mechanism involving continuous breaking and reformation of Nb2O9 units. However, the excess oxygen in CeNbO4.33 hardly migrates because of the high concentration and the ordered distribution of the excess oxide ions. The relationship between the structure and oxide ion migration for the whole series of CeNbO4+δ compounds elucidated here provides a direction for the performance optimization of these compounds.
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18.
  • Li, Xinlei, et al. (författare)
  • Shaped by uneven Pleistocene climate: mitochondrial phylogeographic pattern and population history of White Wagtail Motacilla alba (Aves: Passeriformes).
  • 2016
  • Ingår i: Journal of Avian Biology. - : Wiley. - 0908-8857 .- 1600-048X. ; 47, s. 263-274
  • Tidskriftsartikel (refereegranskat)abstract
    • We studied the phylogeography and population history of the white wagtail Motacilla alba, which has a vast breeding range, covering areas with different Pleistocene climatic histories. The mitochondrial NADH dehydrogenase subunit II gene (ND2) and Control Region (CR) were analyzed for 273 individuals from 45 localities. Our data comprised all nine subspecies of white wagtail. Four primary clades were inferred (M, N, SW and SE), with indications of M. grandis being nested within M. alba. The oldest split was between two haplotypes from the endemic Moroccan M. a. subpersonata (clade M) and the others, at 0.63–0.96 Mya; other divergences were at 0.31–0.38 Mya. The entire differentiation falls within the part of the Pleistocene characterized by Milankovitch cycles of large amplitudes and durations. Clade N was distributed across the northern Palearctic; clade SW in southwestern Asia plus the British Isles and was predicted by Ecological niche models (ENMs) to occur also in central and south Europe; and clade SE was distributed in central and east Asia. e deep divergence within M. a. subpersonata may reflect retention of ancestral haplotypes. Regional differences in historical climates have had different impacts on different populations: clade N expanded after the last glacial maximum (LGM), whereas milder Pleistocene climate of east Asia allowed clade SE a longer expansion time (since MIS 5); clade SW expanded over a similarly long time as clade SE, which is untypical for European species. ENMs supported these conclusions in that the northern part of the Eurasian continent was unsuitable during the LGM, whereas southern parts remained suitable. e recent divergences and poor structure in the mitochondrial tree contrasts strongly with the pronounced, well defined phenotypical differentiation, indicating extremely fast plumage divergence. 
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19.
  • Shen, Zhaoyan, et al. (författare)
  • A Multiagent Reinforcement Learning-Assisted Cache Cleaning Scheme for DM-SMR
  • 2023
  • Ingår i: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0278-0070 .- 1937-4151. ; 42:8, s. 2500-2513
  • Tidskriftsartikel (refereegranskat)abstract
    • To support nonsequential writes, persistent cache (PC) is constructed in drive managed SMR (DM-SMR) drive. However, PC cleaning introduces drastic performance degradation and enlarges tail latencies. In this article, we propose to utilize reinforcement learning (RL) to mitigate the longtail latency of PC cleaning. Our scheme uses the lightweight Q-learning method to monitor and learn the idle time of I/O workloads, based on which PC cleaning is intelligently guided, thus maximally exploit idle time between requests and hiding tail latency from normal requests. In addition, a multiagent RL scheme with clustering algorithm is adopted to further mitigate the tail latencies and adapt to variable workloads. We emulate a DM-SMR drive inside a Linux device driver to implement our proposed scheme. According to the experimental results, our scheme can effectively reduce the tail latency by 59.45% at the 99.9th percentile and the average latency by 48.75% compared with a typical shingled magnetic recording (SMR) design.
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20.
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21.
  • Sun, Jiaqi, et al. (författare)
  • Water-Energy-Food integrated management model under Uncertainty-A case study of Yulin City
  • 2023
  • Ingår i: Journal of Hydrology. - 0022-1694 .- 1879-2707. ; 625
  • Tidskriftsartikel (refereegranskat)abstract
    • Water, energy, and food are indispensable human survival and development resources. With the rapid development of the social economy, the systematic risk of water, energy, and food is becoming increasingly prominent. Water, energy, and food security are threatened to varying degrees. At the same time, water, energy, and food are interrelated, restricted, and interdependent. It is of great scientific significance to reveal and optimize the WEF (Water-Energy-Food) nexus. This study relied on Chance constrained programming and Fuzzy credibility constrained programming to deal with randomness and fuzziness in the WEF nexus. Meanwhile, based on Bi-level programming, aiming at minimizing water allocation and maximizing system benefits, a Water-Energy-Food Integrated Management Model to deal with multiple Uncertainties, called IMMU-WEF model was constructed. The model solved the critical effects of the randomness of water supply and the subjective fuzziness of water demand on water resources allocation, power generation, primary energy extraction, and food planting area. The results showed that the IMMU-WEF model could efficiently deal with the game between different departments in the resource management system, the random uncertainty expressed by probability density, and the fuzzy uncertainty caused by subjective factors. It can develop a stable management scheme for resource management. Applying the mode to Yulin City, China, it is found that water supply and demand fluctuation dramatically impacts on the WEF system benefit, water resources allocation, energy and food production. Specifically, the system benefit will increase over time, with a total benefit of 1974.04 × 108-1998.06 × 108 yuan (2021–2025), 3065.69 × 108-3100.50 × 108 yuan (2026–2030), and 4128.80 × 108-4191.07 × 108 yuan (2031–2035). Additionally, the system water allocation, primary energy extraction, power generation, and food planting are expected to increase over three time periods. With the increase of water supply in the future, the energy and food production in Yulin City show an increasing trend. It indicates that water shortage will continue to be a major problem in Yulin in the three periods, and that the city still needs to increase water supply and diversion projects to ensure energy security and food security. The results can provide an optimal management scheme for ensuring Yulin City’s water, energy, and food security.
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22.
  • Sun, Shiguo, et al. (författare)
  • Synthesis and ECL performance of highly efficient bimetallic ruthenium tris-bipyridyl complexes
  • 2012
  • Ingår i: Dalton Transactions. - : Royal Society of Chemistry (RSC). - 1477-9226 .- 1477-9234. ; 41:40, s. 12434-12438
  • Tidskriftsartikel (refereegranskat)abstract
    • In order to find the ideal carbon chain linkage number n for achieving the highest ECL in bimetallic ruthenium tris-bipyridyl complexes, a series of novel complexes [(bpy)(2)Ru(bpy')(CH2)(n)(bpy')Ru(bpy)(2)](4+) (1, where bpy is 2,2'-bipyridyl, n = 10, 12, 14) for a coreactant electrochemiluminescence (ECL) system have been synthesized. Their ECL properties at a Au electrode have been studied in 0.1 M phosphate buffer by using tripropylamine (TPrA), 2-(dibutylamino)ethanol (DBAE) and melamine as the coreactant, to compare with that of the previously reported bimetallic ruthenium analogous complex [(bpy)(2)Ru(bpy')(CH2)(8)(bpy')Ru(bpy)(2)](4+). The results demonstrate that the ECL intensity depends largely on the length of the saturated carbon chain linkage number n. The highest ECL is reached when n = 10, suggesting that a synergistic effect on ECL enhancement co-exists between the two intramolecular linked ruthenium activating centers. Density functional theory (DFT) calculation demonstrated that the optimized bond distances between Ru and N(bpy') are the longest both in the ground and the excited triplet states in the case of n = 10, while those for Ru and N(bpy) are the shortest in the excited triplet states. All these factors may be responsible for the above mentioned results. This study provided a methodology to further improve and tune ECL efficiency by using bimetallic ruthenium complexes linked by a flexible saturated carbon chain.
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23.
  • Sushko, Iurii, et al. (författare)
  • Applicability Domains for Classification Problems : Benchmarking of Distance to Models for Ames Mutagenicity Set.
  • 2010
  • Ingår i: Journal of chemical information and modeling. - : American Chemical Society (ACS). - 1549-9596 .- 1549-960X. ; 50:12, s. 2094-2111
  • Tidskriftsartikel (refereegranskat)abstract
    • The estimation of accuracy and applicability of QSAR and QSPR models for biological and physicochemical properties represents a critical problem. The developed parameter of "distance to model" (DM) is defined as a metric of similarity between the training and test set compounds that have been subjected to QSAR/QSPR modeling. In our previous work, we demonstrated the utility and optimal performance of DM metrics that have been based on the standard deviation within an ensemble of QSAR models. The current study applies such analysis to 30 QSAR models for the Ames mutagenicity data set that were previously reported within the 2009 QSAR challenge. We demonstrate that the DMs based on an ensemble (consensus) model provide systematically better performance than other DMs. The presented approach identifies 30-60% of compounds having an accuracy of prediction similar to the interlaboratory accuracy of the Ames test, which is estimated to be 90%. Thus, the in silico predictions can be used to halve the cost of experimental measurements by providing a similar prediction accuracy. The developed model has been made publicly available at http://ochem.eu/models/1 .
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24.
  • Van Bavel, Jay J., et al. (författare)
  • National identity predicts public health support during a global pandemic
  • 2022
  • Ingår i: Nature Communications. - : Nature Portfolio. - 2041-1723. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding collective behaviour is an important aspect of managing the pandemic response. Here the authors show in a large global study that participants that reported identifying more strongly with their nation reported greater engagement in public health behaviours and support for public health policies in the context of the pandemic. Changing collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g., spatial distancing and stricter hygiene) and endorsed public policy interventions (e.g., closing bars and restaurants) during the early stage of the COVID-19 pandemic (April-May 2020). Respondents who reported identifying more strongly with their nation consistently reported greater engagement in public health behaviours and support for public health policies. Results were similar for representative and non-representative national samples. Study 2 (N = 42 countries) conceptually replicated the central finding using aggregate indices of national identity (obtained using the World Values Survey) and a measure of actual behaviour change during the pandemic (obtained from Google mobility reports). Higher levels of national identification prior to the pandemic predicted lower mobility during the early stage of the pandemic (r = -0.40). We discuss the potential implications of links between national identity, leadership, and public health for managing COVID-19 and future pandemics.
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25.
  • Wang, Guangwei, et al. (författare)
  • Application of catalysts in biomass hydrothermal carbonization for the preparation of high-quality blast furnace injection fuel
  • 2023
  • Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 283
  • Tidskriftsartikel (refereegranskat)abstract
    • The low energy density of biomass is a crucial limitation for their application in the steel industry. This study used catalyst-catalysed hydrothermal carbonization (HTC) to prepare higher-quality hydrochar from biomass. The effects of acid-base homogeneous catalysts (Fe(NO3)3·9H2O and CaO), liquid phase product (circulating water) and carbonization temperatures on the physicochemical properties and microscopic morphology of hydrochars were investigated. The results showed that higher carbonization temperature, circulating water and Fe(NO3)3·9H2O all raised the higher heating value (HHV) of hydrochar. When 4% of Fe(NO3)3·9H2O was added, the HHV of hydrochar reached 30.05 MJ/kg, which was 1.15 times higher than without catalysts. The above three conditions can also make the ordering degree in the carbonaceous structure lower ordered and enhance the reaction performance of the hydrochar. Meanwhile, the addition of Fe(NO3)3·9H2O at 240 °C can reduce the hydrochar ignition and burnout temperatures and enhance the combustion performance. Moreover, it was demonstrated that circulating water promoted the HTC more than deionized water. In conclusion, adding Fe(NO3)3·9H2O or circulating water to the HTC process can produce higher-quality hydrochar.
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26.
  • Xu, Jiangchang, et al. (författare)
  • Automatic segmentation of orbital wall from CT images via a thin wall region supervision-based multi-scale feature search network
  • 2023
  • Ingår i: International Journal of Computer Assisted Radiology and Surgery. - : Springer Nature. - 1861-6410 .- 1861-6429. ; 18:11, s. 2051-2062
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Orbital wall segmentation is critical for orbital measurement and reconstruction. However, the orbital floor and medial wall are made up of thin walls (TW) with low gradient values, making it difficult to segment the blurred areas of the CT images. Clinically, doctors have to manually repair the missing parts of TW, which is time-consuming and laborious. Methods: To address these issues, this paper proposes an automatic orbital wall segmentation method based on TW region supervision using a multi-scale feature search network. First of all, in the encoding branch, the densely connected atrous spatial pyramid pooling based on the residual connection is adopted to achieve a multi-scale feature search. Then, for feature enhancement, multi-scale up-sampling and residual connection are applied to perform skip connection of features in multi-scale convolution. Finally, we explore a strategy for improving the loss function based on the TW region supervision, which effectively increases the TW region segmentation accuracy. Results: The test results show that the proposed network performs well in terms of automatic segmentation. For the whole orbital wall region, the Dice coefficient (Dice) of segmentation accuracy reaches 96.086 ± 1.049%, the Intersection over Union (IOU) reaches 92.486 ± 1.924%, and the 95% Hausdorff distance (HD) reaches 0.509 ± 0.166 mm. For the TW region, the Dice reaches 91.470 ± 1.739%, the IOU reaches 84.327 ± 2.938%, and the 95% HD reaches 0.481 ± 0.082 mm. Compared with other segmentation networks, the proposed network improves the segmentation accuracy while filling the missing parts in the TW region. Conclusion: In the proposed network, the average segmentation time of each orbital wall is only 4.05 s, obviously improving the segmentation efficiency of doctors. In the future, it may have a practical significance in clinical applications such as preoperative planning for orbital reconstruction, orbital modeling, orbital implant design, and so on.
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27.
  • Ye, Lian, et al. (författare)
  • Feasibility analysis of plastic and biomass hydrochar for blast furnace injection
  • 2023
  • Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 263
  • Tidskriftsartikel (refereegranskat)abstract
    • Hydrothermal carbonization (HTC) technology upgrades combustible waste (CW) to high-quality fuel known as hydrochar. However, there is a research gap regarding the application limit of hydrochar instead of fossil fuels in blast furnaces. In this study, the physical, chemical, and metallurgical properties of hydrochar were thoroughly analyzed. The results showed that gross calorific value, grindability, ignition temperature, explosivity, combustion and gasification all improved by HTC process compared with the waste feedstocks. Moreover, the HTC process can effectively remove harmful elements (K, Na, Cl, and S) from feedstocks into liquid and gas phase without adding other reagents, reducing harmful effects in the blast furnace. Removal rates by HTC were >80% for alkali metals and >73.9% for Cl (reaching 98.18% for polyvinyl chloride hydrochar). The environmental benefit calculation shows that the CO2 emission reduction of replacing bituminous coal with 40% HTC-treated maize straw can reach 94.7 kg/tHM. The annual CO2 reduction can reach 1.7 x 107 kg and the annual coal reduction is 1.5 x 107 kg of a blast furnace. The results showed that hydrochar is a clean energy source compared with fossil fuel alternatives and meets the blast furnace injection requirements.
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28.
  • You, Fang, et al. (författare)
  • Icon Design Recommendations for Central Consoles of Intelligent Vehicles
  • 2020
  • Ingår i: Human Interaction, Emerging Technologies and Future Applications II. - Cham : Springer. - 9783030442668 - 9783030442675 ; , s. 285-291
  • Konferensbidrag (refereegranskat)abstract
    • Advances in vehicle technology open up both opportunities and challenges for human-machine interface (HMI) design in intelligent vehicles. Design guidelines for icons in central consoles of vehicles have been discussed in human-computer interaction community, but more study and innovation are needed in icon design. In this paper, we investigated the displayed line thickness and size of icons in the intelligent vehicle’s central control screen, based on international design guidelines and standards. The experiment involved 17 participants performing simulated in-vehicle secondary task. The result from the experiments shows that the usability of icons increases and the driver’s workload decreases as the icons get larger. We also found a set of recommended values for size and line thickness of icons in this context. Future work will focus on providing design guidelines for other aspects of HMI design in intelligent vehicles.
  •  
29.
  • Zhang, Nan, et al. (författare)
  • Physicochemical characteristics of three-phase products of low-rank coal by hydrothermal carbonization : experimental research and quantum chemical calculation
  • 2022
  • Ingår i: Energy. - : Elsevier BV. - 0360-5442 .- 1873-6785. ; 261
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, the distribution characteristics of gas, liquid, and solid products of low-rank coal by hydrothermal carbonization (HTC) at different temperatures are studied. Advanced testing methods are used to explore changing rules of physicochemical characteristics. Reaction properties of different regions are explained based on the mechanism of quantum chemistry. Experimental results showed that as the temperature increases, the volatile content decreases, the fixed carbon content increases, and impurities are removed in the form of gas or ions. The coal aliphatic properties are reduced, whereas the aromatization degree is significantly enhanced. Meanwhile, the specific surface area after upgrading is reduced, but the average pore diameter is increased, and the pore structure density is enhanced. The content of carbon-containing groups increases but that of carbon-oxygen groups decreases, which corresponds to the O/C ratio. Theoretical calculation results demonstrate that the more negative and positive areas of the surface electrostatic potential (ESP), the smaller distribution proportion. The ESP value in the vicinity of oxygen-containing group is relatively negative, indicating that it is more reactive, which is a good proof of the experiment's conclusions. In summary, low-rank coal obtained after HTC meets the blast furnace injection requirements and can be used for injection.
  •  
30.
  •  
31.
  • Zou, Xianshao, et al. (författare)
  • Carrier Recombination Processes in GaAs Wafers Passivated by Wet Nitridation
  • 2020
  • Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:25, s. 28360-28367
  • Tidskriftsartikel (refereegranskat)abstract
    • As one of the successful approaches to GaAs surface passivation, wet-chemical nitridation is applied here to relate the effect of surface passivation to carrier recombination processes in bulk GaAs. By combining time-resolved photoluminescence and optical pump-THz probe measurements, we found that surface hole trapping dominates the decay of photoluminescence, while photoconductivity dynamics is limited by surface electron trapping. Compared to untreated sample dynamics, the optimized nitridation reduces hole- and electron-trapping rate by at least 2.6 and 3 times, respectively. Our results indicate that under ambient conditions, recovery of the fast hole trapping due to the oxide regrowth at the deoxidized GaAs surface takes tens of hours, while it is effectively inhibited by surface nitridation. Our study demonstrates that surface nitridation stabilizes the GaAs surface via reduction of both electron- and hole-trapping rates, which results in chemical and electronical passivation of the bulk GaAs surface.
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