| 1. |
- Yuan, Qin, et al.
(författare)
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Aridification signatures from fossil pollen indicate a drying climate in east-central Tibet during the late Eocene
- 2020
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Ingår i: Climate of the Past. - Vienna : European Geosciences Union (EGU). - 1744-9588 .- 1814-9332 .- 1814-9324. ; 16, s. 2255-2273
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Tidskriftsartikel (refereegranskat)abstract
- Central Asia experienced a number of significant elevational and climatic changes during the Cenozoic, but much remains to be understood regarding the timing and driving mechanisms of these changes as well as their influence on ancient ecosystems. Here, we describe the palaeoecology and palaeoclimate of a new section from the Nangqian Basin in Tibet, north-western China, dated as Bartonian (41.2–37.8 Ma; late Eocene) based on our palynological analyses. Located on the east-central part of what is today the Tibetan Plateau, this section is excellently placed for better understanding the palaeoecological history of Tibet following the Indo-Asian collision. Our new palynological record reveals that a strongly seasonal steppe–desert ecosystem characterized by drought-tolerant shrubs, diverse ferns, and an underlying component of broad-leaved forests existed in east-central Tibet during the Eocene, influenced by a southern monsoon. A transient warming event, possibly the middle Eocene climatic optimum (MECO; 40 Ma), is reflected in our record by a temporary increase in regional tropical taxa and a concurrent decrease in steppe–desert vegetation. In the late Eocene, a drying signature in the palynological record is linked to proto-Paratethys Sea retreat, which caused widespread long-term aridification across the region. To better distinguish between local climatic variation and farther-reaching drivers of Central Asian palaeoclimate and elevation, we correlated key palynological sections across the Tibetan Plateau by means of established radioisotopic ages and biostratigraphy. This new palynozonation illustrates both intra- and inter-basinal floral response to Qinghai–Tibetan uplift and global climate change during the Paleogene, and it provides a framework for the age assignment of future palynological studies in Central Asia. Our work highlights the ongoing challenge of integrating various deep time records for the purpose of reconstructing palaeoelevation, indicating that a multi-proxy approach is vital for unravelling the complex uplift history of Tibet and its resulting influence on Asian climate.
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| 2. |
- Bhat, Goutam, et al.
(författare)
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NTIRE 2022 Burst Super-Resolution Challenge
- 2022
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Ingår i: 2022 IEEE/CVF CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION WORKSHOPS (CVPRW 2022). - : IEEE. - 9781665487399 - 9781665487405 ; , s. 1040-1060
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Konferensbidrag (refereegranskat)abstract
- Burst super-resolution has received increased attention in recent years due to its applications in mobile photography. By merging information from multiple shifted images of a scene, burst super-resolution aims to recover details which otherwise cannot be obtained using a simple input image. This paper reviews the NTIRE 2022 challenge on burst super-resolution. In the challenge, the participants were tasked with generating a clean RGB image with 4x higher resolution, given a RAW noisy burst as input. That is, the methods need to perform joint denoising, demosaicking, and super-resolution. The challenge consisted of 2 tracks. Track 1 employed synthetic data, where pixel-accurate high-resolution ground truths are available. Track 2 on the other hand used real-world bursts captured from a handheld camera, along with approximately aligned reference images captured using a DSLR. 14 teams participated in the final testing phase. The top performing methods establish a new state-of-the-art on the burst super-resolution task.
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| 3. |
- Cao, Yuehan, et al.
(författare)
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Modulating electron density of vacancy site by single Au atom for effective CO2 photoreduction
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- The surface electron density significantly affects the photocatalytic efficiency, especially the photocatalytic CO2 reduction reaction, which involves multi-electron participation in the conversion process. Herein, we propose a conceptually different mechanism for surface electron density modulation based on the model of Au anchored CdS. We firstly manipulate the direction of electron transfer by regulating the vacancy types of CdS. When electrons accumulate on vacancies instead of single Au atoms, the adsorption types of CO2 change from physical adsorption to chemical adsorption. More importantly, the surface electron density is manipulated by controlling the size of Au nanostructures. When Au nanoclusters downsize to single Au atoms, the strong hybridization of Au 5d and S 2p orbits accelerates the photo-electrons transfer onto the surface, resulting in more electrons available for CO2 reduction. As a result, the product generation rate of AuSA/Cd1−xS manifests a remarkable at least 113-fold enhancement compared with pristine Cd1−xS.
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| 4. |
- Chen, Ling, et al.
(författare)
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Reliable and efficient RAR-based distributed model training in computing power network
- 2024
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Ingår i: Journal of Optical Communications and Networking. - 1943-0620 .- 1943-0639. ; 16:5, s. 527-540
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Tidskriftsartikel (refereegranskat)abstract
- The computing power network (CPN) is a novel network technology that integrates computing power from the cloud, edge, and terminals using IP/optical cross-layer networks for distributed computing. CPNs can provide an effective solution for distributed model training (DMT). As a bandwidth optimization architecture based on data parallelism, ring all-reduce (RAR) is widely used in DMT. However, any node or link failure on the ring can interrupt or block the requests deployed on the ring. Meanwhile, due to the resource competition of batch RAR-based DMT requests, inappropriate scheduling strategies will also lead to low training efficiency or congestion. As far as we know, there is currently no research that considers the survivability of rings in scheduling strategies for RAR-based DMT. To fill this gap, we propose a scheduling scheme for RAR-based DMT requests in CPNs to optimize the allocation of computing and wavelength resources considering the time dimension while ensuring reliability. In practical scenarios, service providers may focus on different performance metrics. We formulate an integer linear programming (ILP) model and a RAR-based DMT deployment algorithm (RDDA) to solve this problem considering four optimization objectives under the premise of the minimum blocking rate: minimum computing resource consumption, minimum wavelength resource consumption, minimum training time, and maximum reliability. Simulation results demonstrate that our model satisfies the reliability requirements while achieving corresponding optimal performance for DMT requests under four optimization objectives.
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| 5. |
- Cheng, Jie, et al.
(författare)
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Corrosion- and wear-resistant composite film of graphene and mussel adhesive proteins on carbon steel
- 2020
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Ingår i: Corrosion Science. - : Elsevier. - 0010-938X .- 1879-0496. ; 164
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Tidskriftsartikel (refereegranskat)abstract
- A new strategy was proposed to prepare a composite film using mussel adhesive protein Mefp-1 and graphene to achieve corrosion protection and surface lubrication on carbon steel. The dispersibility of graphene in Mefp-1 solution was firstly investigated and deposition methods of Mefp-1/graphene film were proposed. In-situ confocal Raman micro-spectroscopy and electrochemical impedance spectroscopy measurements were utilized to study the corrosion inhibition effect in NaCl solution. Friction tests were conducted to study the tribological properties. Results show that the Mefp-1/graphene film exhibits strong adhesion to carbon steel, provides improved corrosion- and wear-resistance, and a significantly increased lubricity on carbon steel.
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| 6. |
- Cheng, Jie, et al.
(författare)
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Interactions in Composite Film Formation of Mefp-1/graphene on Carbon Steel
- 2021
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- Mefp-1 adhesive protein derived from marine blue mussels, together with the 2D material graphene, was used to build the green composite film with enhanced anti-corrosion property and mechanical strength. The corrosion inhibition of the composite film, formed by different methods, was evaluated by using electrochemical impedance spectroscopy. The non-degraded adhesion of the composite film to the carbon steel substrate was proved by nano-scratch tests. Infrared spectroscopy was utilized to investigate the film formation process and "three-body interactions " between Mefp-1, graphene and carbon steel surface. The results show that the Mefp-1 adsorbs on the carbon steel surface mainly through the covalent bond between catechols and Fe(III). Meanwhile, Mefp-1 can bond to non-adhesive graphene by forming hydrogen bonds and pi-pi interaction non-covalent bonds, which facilitate the formation of a robust Mefp-1/graphene composite film on the carbon steel surface.
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| 7. |
- Fan, Jieyu, et al.
(författare)
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Evaluating the Impact of Signal Control on Emissions at Intersections
- 2022
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Ingår i: Smart Innovation, Systems and Technologies. - Singapore : Springer Nature Singapore. - 2190-3026 .- 2190-3018. ; 304 SIST, s. 104-111
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Konferensbidrag (refereegranskat)abstract
- Transport emission has become an increasingly serious problem, and it is an urgent issue in sustainable transport. In this study, by constructing traffic emission models for different vehicle types and operating conditions, the changes in CO, HC, and NOx emissions of light-duty and heavy-duty vehicles before and after signal control optimization were quantified based on VISSIM simulation. The OBEAS-3000 vehicle emission testing device was used to collect data on the micro-operational characteristics of different vehicles under different operating conditions as well as traffic emission data. Based on the data collected, the VSP (Vehicle Specific Power) model combined with the VISSIM traffic simulation platform was used to calculate the emissions of light and heavy vehicles in the mixed traffic flow before and after intersection signal optimization. It is known from the study that signal control optimization has a greater impact on heavy vehicles than on light vehicles. Emissions of CO, HC, and NOx from heavy vehicles and light vehicles are all reduced, but NOx emissions from light vehicles remain largely unchanged. The research results reveal the emission patterns of light and heavy vehicles in different micro-operating conditions and establish a traffic emission model. It provides a theoretical basis for accurate traffic emission analysis and traffic flow optimization, as well as a scientific basis for the formulation of traffic management measures and emission reduction in large city transport systems.
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| 8. |
- Fan, Qunping, et al.
(författare)
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Unidirectional Sidechain Engineering to Construct Dual-Asymmetric Acceptors for 19.23 % Efficiency Organic Solar Cells with Low Energy Loss and Efficient Charge Transfer
- 2023
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Ingår i: Angewandte Chemie International Edition. - : WILEY-V C H VERLAG GMBH. - 1433-7851 .- 1521-3773. ; 62:36
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Tidskriftsartikel (refereegranskat)abstract
- Achieving both high open-circuit voltage (V-oc) and short-circuit current density (J(sc)) to boost power-conversion efficiency (PCE) is a major challenge for organic solar cells (OSCs), wherein high energy loss (E-loss) and inefficient charge transfer usually take place. Here, three new Y-series acceptors of mono-asymmetric asy-YC11 and dual-asymmetric bi-asy-YC9 and bi-asy-YC12 are developed. They share the same asymmetric D(1)AD(2) (D-1=thieno[3,2-b]thiophene and D-2=selenopheno[3,2-b]thiophene) fused-core but have different unidirectional sidechain on D-1 side, allowing fine-tuned molecular properties, such as intermolecular interaction, packing pattern, and crystallinity. Among the binary blends, the PM6 : bi-asy-YC12 one has better morphology with appropriate phase separation and higher order packing than the PM6 : asy-YC9 and PM6 : bi-asy-YC11 ones. Therefore, the PM6 : bi-asy-YC12-based OSCs offer a higher PCE of 17.16 % with both high V-oc and J(sc), due to the reduced E-loss and efficient charge transfer properties. Inspired by the high V-oc and strong NIR-absorption, bi-asy-YC12 is introduced into efficient binary PM6 : L8-BO to construct ternary OSCs. Thanks to the broadened absorption, optimized morphology, and furtherly minimized E-loss, the PM6 : L8-BO : bi-asy-YC12-based OSCs achieve a champion PCE of 19.23 %, which is one of the highest efficiencies among these annealing-free devices. Our developed unidirectional sidechain engineering for constructing bi-asymmetric Y-series acceptors provides an approach to boost PCE of OSCs.
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| 9. |
- Fan, Xuge, et al.
(författare)
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Resonant Transducers Consisting of Graphene Ribbons with Attached Proof Masses for NEMS Sensors
- 2023
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 7:1, s. 102-109
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Tidskriftsartikel (refereegranskat)abstract
- The unique mechanical and electrical properties of graphene make it an exciting material for nanoelectromechanical systems (NEMS). NEMS resonators with graphene springs facilitate studies of graphene's fundamental material characteristics and thus enable innovative device concepts for applications such as sensors. Here, we demonstrate resonant transducers with ribbon-springs made of double-layer graphene and proof masses made of silicon and study their nonlinear mechanics at resonance both in air and in vacuum by laser Doppler vibrometry. Surprisingly, we observe spring-stiffening and spring-softening at resonance, depending on the graphene spring designs. The measured quality factors of the resonators in a vacuum are between 150 and 350. These results pave the way for a class of ultraminiaturized nanomechanical sensors such as accelerometers by contributing to the understanding of the dynamics of transducers based on graphene ribbons with an attached proof mass.
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| 10. |
- Guo, Di, et al.
(författare)
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Cholecystokinin-like peptide mediates satiety by inhibiting sugar attraction
- 2021
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 17:8
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Tidskriftsartikel (refereegranskat)abstract
- Feeding is essential for animal survival and reproduction and is regulated by both internal states and external stimuli. However, little is known about how internal states influence the perception of external sensory cues that regulate feeding behavior. Here, we investigated the neuronal and molecular mechanisms behind nutritional state-mediated regulation of gustatory perception in control of feeding behavior in the brown planthopper and Drosophila. We found that feeding increases the expression of the cholecystokinin-like peptide, sulfakinin (SK), and the activity of a set of SK-expressing neurons. Starvation elevates the transcription of the sugar receptor Gr64f and SK negatively regulates the expression of Gr64f in both insects. Interestingly, we found that one of the two known SK receptors, CCKLR-17D3, is expressed by some of Gr64f-expressing neurons in the proboscis and proleg tarsi. Thus, we have identified SK as a neuropeptide signal in a neuronal circuitry that responds to food intake, and regulates feeding behavior by diminishing gustatory receptor gene expression and activity of sweet sensing GRNs. Our findings demonstrate one nutritional state-dependent pathway that modulates sweet perception and thereby feeding behavior, but our experiments cannot exclude further parallel pathways. Importantly, we show that the underlying mechanisms are conserved in the two distantly related insect species.
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