| 1. |
- Kristan, Matej, et al.
(författare)
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The Ninth Visual Object Tracking VOT2021 Challenge Results
- 2021
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Ingår i: 2021 IEEE/CVF INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW 2021). - : IEEE COMPUTER SOC. - 9781665401913 ; , s. 2711-2738
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Konferensbidrag (refereegranskat)abstract
- The Visual Object Tracking challenge VOT2021 is the ninth annual tracker benchmarking activity organized by the VOT initiative. Results of 71 trackers are presented; many are state-of-the-art trackers published at major computer vision conferences or in journals in recent years. The VOT2021 challenge was composed of four sub-challenges focusing on different tracking domains: (i) VOT-ST2021 challenge focused on short-term tracking in RGB, (ii) VOT-RT2021 challenge focused on "real-time" short-term tracking in RGB, (iii) VOT-LT2021 focused on long-term tracking, namely coping with target disappearance and reappearance and (iv) VOT-RGBD2021 challenge focused on long-term tracking in RGB and depth imagery. The VOT-ST2021 dataset was refreshed, while VOT-RGBD2021 introduces a training dataset and sequestered dataset for winner identification. The source code for most of the trackers, the datasets, the evaluation kit and the results along with the source code for most trackers are publicly available at the challenge website(1).
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| 2. |
- Li, Weihua, et al.
(författare)
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Controllable and large-scale synthesis of carbon quantum dots for efficient solid-state optical devices
- 2024
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Ingår i: Nano Energy. - : Elsevier Ltd. - 2211-2855 .- 2211-3282. ; 122
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Tidskriftsartikel (refereegranskat)abstract
- Carbon quantum dots (C-dots) showed excellent structure-tunable optical properties, mainly composed of carbon, nitrogen and oxygen. They have been used for various types of solid-state optical devices. Due to the photoluminescence quenching caused by aggregation, it is a challenge to produce high quantum yield and large Stokes shift C-dots via controllable and simple approaches. In this work, we demonstrated a microwave assisted heating approach for the high-quality C-dots production with ten grams scale per batch in less than 4 min. The addition of metal cation promoted the formation of the foam-structure by forming carboxyl-metal-amine complex, enabling the spatial confined growth of the C-dots in a solid-state, contributing to the high quantum yield (QY) of 73% with a Stokes shift of 0.65 eV. By tuning the structure of the C-dots, excitation dependent and independent photoluminescent (PL) behavior were achieved because of the formation of the different types of energy states evidenced by transient PL and femtosecond transient absorption spectroscopy. These optical properties enable the C-dots to be successfully integrated in luminescent solar concentrators (LSCs), having an external optical efficiency of 3.0% and a power conversion efficiency of 1.3% (225 cm2) and an excitation-dependent high-level anticounterfeiting fluorescent code, showing a great potential for solid-state optical system.
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| 3. |
- Ren, Shihuan, et al.
(författare)
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Near-infrared heavy-metal-free SnSe/ZnSe quantum dots for efficient photoelectrochemical hydrogen generation
- 2021
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Ingår i: Nanoscale. - : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 13:6, s. 3519-3527
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Tidskriftsartikel (refereegranskat)abstract
- Solar-driven photoelectrochemical (PEC) hydrogen production is one of the most effective strategies for solar-to-hydrogen energy conversion. Among various types of semiconductors used for PEC anodes, colloidal quantum dots (QDs) have been widely used as new and promising absorbers for PEC and other optoelectronic devices. However, currently, most efficient optoelectronic devices contain toxic Pb/Cd elements or non-earth-abundant elements (In/Ag). It is still a challenge to produce Pb/Cd-free QDs without using any toxic and non-earth-abundant elements. Here, we synthesized SnSe QDs via a diffusion-controlled hot injection approach and further stabilized the as-prepared SnSe QDs via a cation exchange reaction. The as-synthesized Zn-stabilized SnSe QDs (SnSe/ZnSe) have an orthorhombic crystal structure with indirect bandgaps ranging from 1 to 1.37 eV. Zn stabilization can significantly decrease the number of QD surface metallic Sn bonds, thereby decreasing the number of recombination centers of defects/traps. As a proof-of-concept, SnSe/ZnSe QDs are used as light absorbers for PEC hydrogen production, leading to a saturated photocurrent density of 7 mA cm−2, which is comparable to best values reported for PEC devices based on toxic-metal-free QDs. Our results indicate that Zn-stabilized SnSe QDs have great potential for use in emerging optoelectronic devices.
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| 4. |
- Shi, Weibo, et al.
(författare)
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Optimizing Observation Plans for Identifying Faxon Fir (Abies fargesii var. Faxoniana) Using Monthly Unmanned Aerial Vehicle Imagery
- 2023
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Ingår i: Remote Sensing. - 2072-4292. ; 15:8
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Tidskriftsartikel (refereegranskat)abstract
- Faxon fir (Abies fargesii var. faxoniana), as a dominant tree species in the subalpine coniferous forest of Southwest China, has strict requirements regarding the temperature and humidity of the growing environment. Therefore, the dynamic and continuous monitoring of Faxon fir distribution is very important to protect this highly sensitive ecological environment. Here, we combined unmanned aerial vehicle (UAV) imagery and convolutional neural networks (CNNs) to identify Faxon fir and explored the identification capabilities of multispectral (five bands) and red-green-blue (RGB) imagery under different months. For a case study area in Wanglang Nature Reserve, Southwest China, we acquired monthly RGB and multispectral images on six occasions over the growing season. We found that the accuracy of RGB imagery varied considerably (the highest intersection over union (IoU), 83.72%, was in April and the lowest, 76.81%, was in June), while the accuracy of multispectral imagery was consistently high (IoU > 81%). In April and October, the accuracy of the RGB imagery was slightly higher than that of multispectral imagery, but for the other months, multispectral imagery was more accurate (IoU was nearly 6% higher than those of the RGB imagery for June). Adding vegetation indices (VIs) improved the accuracy of the RGB models during summer, but there was still a gap to the multispectral model. Hence, our results indicate that the optimized time of the year for identifying Faxon fir using UAV imagery is during the peak of the growing season when using a multispectral imagery. During the non-growing season, RGB imagery was no worse or even slightly better than multispectral imagery for Faxon fir identification. Our study can provide guidance for optimizing observation plans regarding data collection time and UAV loads and could further help enhance the utility of UAVs in forestry and ecological research.
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| 5. |
- Wang, Luan, et al.
(författare)
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Different Distribution of Core Microbiota in Upper Soil Layer in Two Places of North China Plain
- 2022
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Ingår i: Open Microbiology Journal. - : Bentham Science Publishers Ltd.. - 1874-2858 .- 1874-2858. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Backgrounds: Soils harbor diverse bacteria, and these bacteria play important roles in soil nutrition cycling and carbon storage. Numerous investigations of soil microbiota had been performed, and the core microbiota in different soil or vegetation soil types had been described. The upper layer of soil, as a source of organic matter, is important and affected by the habitats and dominant bacteria. However, the complexity of soil environments and relatively limited information of many geographic areas had attracted great attention on comprehensive exploration of soil microbes in enormous types of soil. Methods: To reveal the core upper layer soil microbiota, soil samples from metropolis and countryside regions in the North China Plain were investigated using high-throughput sequencing strategy. Results: The results showed that the most dominant bacteria are Proteobacteria (38.34%), Actinobacteria (20.56%), and Acidobacteria (15.18%). At the genus-level, the most abundant known genera are Gaiella (3.66%), Sphingomonas (3.6%), Acidobacteria Gp6 (3.52%), and Nocardioides (2.1%). Moreover, several dominant operational taxanomy units OTUs, such as OTU_3 and OTU_17, were identified to be associated with the soil environment. Microbial distributions of the metropolis samples were different from the countryside samples, which may reflect the environments in the countryside were more diverse than in the metropolis. Microbial diversity and evenness were higher in the metropolis than in the countryside, which might due to the fact that human activity increased the microbial diversity in the metropolis. Conclusion: The upper layer soil core microbiota of the North China Plain were complex, and microbial distributions in these two places might be mainly affected by the human activity and environmental factors, not by the distance. Our data highlights the upper layer soil core microbiota in North China Plain, and provides insights for future soil microbial distribution studies in central China.
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| 6. |
- Wang, Xiaohan, et al.
(författare)
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Colloidal carbon quantum dots as light absorber for efficient and stable ecofriendly photoelectrochemical hydrogen generation
- 2021
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Ingår i: Nano Energy. - : Elsevier. - 2211-2855 .- 2211-3282. ; 86
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Tidskriftsartikel (refereegranskat)abstract
- Solar-driven hydrogen production is one of the most promising strategies for solar-to-hydrogen energy conversion. Compared to inorganic quantum dots (QDs), carbon quantum dots (C-dots) have attracted a lot of attention for optoelectronic devices due to their structure-dependent optical properties and green composition. However, the solar-to-hydrogen conversion efficiency of most of the photoelectrochemical (PEC) devices based on colloidal QDs is still low. Here we demonstrated a highly efficient and stable ecofriendly PEC device using C-dots sensitized TiO2 photoanode, Pt loaded on carbon nanofibers as counter electrode, and glucose aqueous solution as electrolyte. The red-color C-dots were prepared using a solvothermal reaction, with an absorption spectrum ranging from 300 to 600 nm and a quantum yield (QY) of 50%. The C-dots have excitation independent photoluminescence peak positions and highly crystalline structure. The hydroxyl group on the C-dots can strongly interact with the TiO2, forming a very stable complex. Benefiting from these features, the PEC devices based on C-dots exhibit a saturated photocurrent density as high as ~4 mA/cm2 at 0.6 V vs. RHE and the device is very stable (keeping 95% of its initial value after 10-hour illumination upon 100 mW/cm2). This work indicates the promising properties of the C-dots/TiO2 system, which holds huge potential for applications in the fields of optoelectronic and catalytic devices.
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| 7. |
- Wang, Xiaohan, et al.
(författare)
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Skin-Inspired Healable Conductive Elastomers with Exceptional Strain-Adaptive Stiffening and Damage Tolerance
- 2021
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 54:23, s. 10767-10775
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Tidskriftsartikel (refereegranskat)abstract
- Stretchable conductive elastomers play an irreplaceable role in flexible electronic devices. However, stretchable conductive elastomers are usually soft and susceptible to damage. In this study, inspired from skin, highly stretchable and elastic conductive elastomers integrated with damage resistance, damage tolerance, and healability are fabricated by loading ionic liquids (ILs) within the polyurethane (PU) elastomers of the multiblock polymers of poly(dimethylsiloxane) (PDMS)/polycaprolactone (PCL) coordinated with Zn2+ ions. The mechanically robust conductive elastomer, with a tensile strength of ∼15.2 MPa and a stretchability of ∼2668%, has a satisfactory ionic conductivity of 2.9 × 10–4 S cm–1. The conductive elastomer exhibits exceptional strain-adaptive stiffening, with an ∼100-fold increase in modulus when being fully stretched. The strain-adaptive stiffening endows the elastomer with excellent damage resistance. Meanwhile, the conductive elastomer has a record-high fracture energy of ∼33.8 kJ m–2. The notched conductive elastomer can prevent the propagation of the notch up to a strain of ∼2400%. The exceptional strain-adaptive stiffening and damage tolerance originate from the in situ formed phase-separated domains, which are deformable and disintegrable under an external force to significantly strengthen the elastomer and dissipate energy. Furthermore, the conductive elastomer can be conveniently healed under heating to restore its original conductivity and mechanical properties.
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| 8. |
- Zhang, Jinhui, et al.
(författare)
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VEGFA165 gene therapy ameliorates blood-labyrinth barrier breakdown and hearing loss
- 2021
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Ingår i: JCI Insight. - : American Society for Clinical Investigation. - 2379-3708. ; 6:8
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Tidskriftsartikel (refereegranskat)abstract
- Millions of people are affected by hearing loss. Hearing loss is frequently caused by noise or aging and often associated with loss of pericytes. Pericytes populate the small vessels in the adult cochlea. However, their role in different types of hearing loss is largely unknown. Using an inducible and conditional pericyte depletion mouse model and noise-exposed mouse model, we show that loss of pericytes leads to marked changes in vascular structure, in turn leading to vascular degeneration and hearing loss. In vitro, using advanced tissue explants from pericyte fluorescence reporter models combined with exogenous donor pericytes, we show that pericytes, signaled by VEGF isoform A165 (VEGFA165), vigorously drive new vessel growth in both adult and neonatal mouse inner ear tissue. In vivo, the delivery of an adeno-associated virus serotype 1-mediated (AAV1-mediated) VEGFA165 viral vector to pericyte-depleted or noise-exposed animals prevented and regenerated lost pericytes, improved blood supply, and attenuated hearing loss. These studies provide the first clear-cut evidence that pericytes are critical for vascular regeneration, vascular stability, and hearing in adults. The restoration of vascular function in the damaged cochlea, including in noise-exposed animals, suggests that VEGFA165 gene therapy could be a new strategy for ameliorating vascular associated hearing disorders.
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| 9. |
- Zhao, Haiguang, et al.
(författare)
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Gram-scale synthesis of carbon quantum dots with a large Stokes shift for the fabrication of eco-friendly and high-efficiency luminescent solar concentrators
- 2021
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Ingår i: Energy & Environmental Science. - : Royal Society of Chemistry. - 1754-5692 .- 1754-5706. ; 14:1, s. 396-406
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Tidskriftsartikel (refereegranskat)abstract
- Luminescent solar concentrators (LSCs) are large-area sunlight collectors coupled to small area solar cells, for efficient solar-to-electricity conversion. The three key points for the successful market penetration of LSCs are: (i) removal of light losses due to reabsorption during light collection; (ii) high light-to-electrical power conversion efficiency of the final device; (iii) long-term stability of the LSC structure related to the stability of both the matrix and the luminophores. Among various types of fluorophores, carbon quantum dots (C-dots) offer a wide absorption spectrum, high quantum yield, non-toxicity, environmental friendliness, low-cost, and eco-friendly synthetic methods. However, they are characterized by a relatively small Stokes shift, compared to inorganic quantum dots, which limits the highest external optical efficiency that can be obtained for a large-area single-layer LSC (>100 cm2) based on C-dots below 2%. Herein, we report highly efficient large-area LSCs (100–225 cm2) based on colloidal C-dots synthesized via a space-confined vacuum-heating approach. This one batch reaction could produce Gram-scale C-dots with a high quantum yield (QY) (∼65%) using eco-friendly citric acid and urea as precursors. Thanks to their very narrow size distribution, the C-dots produced via the space-confined vacuum-heating approach had a large Stokes shift of 0.53 eV, 50% larger than C-dots synthesized via a standard solvothermal reaction using the same precursors with a similar absorption range. The large-area LSC (15 × 15 × 0.5 cm3) prepared by using polyvinyl pyrrolidone (PVP) polymer as a matrix exhibited an external optical efficiency of 2.2% (under natural sun irradiation, 60 mW cm−2, uncharacterized spectrum). After coupling to silicon solar cells, the LSC exhibited a power conversion efficiency (PCE) of 1.13% under natural sunlight illumination (20 mW cm−2, uncharacterized spectrum). These unprecedented results were obtained by completely suppressing the reabsorption losses during light collection, as proved by optical spectroscopy. These findings demonstrate the possibility of obtaining eco-friendly, high-efficiency, large-area LSCs through scalable production techniques, paving the way to the lab-to-fab transition of this kind of devices.
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