| 152451. |
- Liu, Yuqi, et al.
(författare)
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Digital Twins of Wave Energy Generation Based on Artificial Intelligence
- 2022
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Ingår i: 2022 IEEE Conference on Virtual Reality and 3D User Interfaces Abstracts and Workshops (VRW). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781665484022 - 9781665484039 ; , s. 718-719
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Konferensbidrag (refereegranskat)abstract
- Ocean waves provide a large amount of renewable energy, and Wave energy converter (WEC) can convert wave energy into electric energy. This paper proposes a visualization platform for wave power generation. The platform can monitor various indicators of wave power generation in real time, combined with Long Short-Term Memory (LSTM) neural network to predict wave power and electricity consumption. We make digital twins of a wave power plant in a computer, allowing users to remotely view the factory through VR glasses.
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| 152452. |
- Liu, Yawen
(författare)
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Dimethyl-sulfoxide-assisted improvement in the crystallization of lead-acetate-based perovskites for high-performance solar cells
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Organic lead trihalide perovskite materials have attracted considerable interest for their successful application as light absorbers in efficient photovoltaic cells. Several lead sources have been used for thepreparation of perovskites, among which lead acetate (Pb(Ac)2) is an important candidate. However, simply mixing Pb(Ac)2 and methylamine iodide in N,N-dimethylformamide solvent leads to poor perovskite morphology, which is disadvantageous for the device performance. Herein, we used dimethyl sulfoxide (DMSO) as a solvent additive to improve the quality of Pb(Ac)2-based perovskite films. We observed that using 5.0% DMSO could significantly enhance the crystallinity of the perovskite film with enlarged domain size. Consequently, the power conversion efficiency (PCE) of the relevant perovskite Solar cells (PSCs) was drastically enhanced from 12.88 to 16.59% (on average), with simultaneous improvement in the open-circuit voltage, short-circuit current density, and fill factor. A champion PCE of 17.06% with negligible hysteresis was achieved for PSCs prepared using 5.0% DMSO as the solvent additive. Our results indicate that using DMSO for the preparation of a Pb(Ac)2-based perovskite film is an effective way to fabricate high-performance PSCs
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| 152453. |
- Liu, Yiming, et al.
(författare)
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Dissipative Mechano-Electro-Magnetism Simulations in Electronic Components
- 2023
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Ingår i: Sixty Shades of Generalized Continua. - Cham : Springer. - 9783031261855 - 9783031261886 - 9783031261862 ; , s. 463-478
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Bokkapitel (refereegranskat)abstract
- Especially at high frequencies, as they occur in 5G or relevant applications, electromagnetism in electronic components plays a significant role in system behavior. Moreover, dissipative effects are triggered by mechanical deformation. Indeed, dissipation is an energy loss and thus the industry tries to minimize this effect by optimizing the design. We examine this justification by using multiphysics simulations by means of the Finite Element Method (FEM) and solve deformation and dissipative dielectric material equations for a simple electronic component in a monolithic manner.
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| 152454. |
- Liu, Yan, et al.
(författare)
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Dynamic niche-specific adaptations in Neisseria meningitidis during infection
- 2016
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Ingår i: Microbes and infection. - : Elsevier BV. - 1286-4579 .- 1769-714X. ; 18:2, s. 109-117
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Tidskriftsartikel (refereegranskat)abstract
- Neisseria meningitidis is an opportunistic human pathogen that usually colonizes the nasopharyngeal mucosa asymptomatically. Upon invasion into the blood and central nervous system, this bacterium triggers a fulminant inflammatory reaction with the manifestations of septicemia and meningitis, causing high morbidity and mortality. To reveal the bacterial adaptations to specific and dynamic host environments, we performed a comprehensive proteomic survey of N. meningitidis isolated from the nasal mucosa, CSF and blood of a mouse disease model. We could identify 51 proteins whose expression pattern has been changed during infection, many of which have not yet been characterized. The abundance of proteins was markedly lower in the bacteria isolated from the nasal mucosa compared to the bacteria from the blood and CSF, indicating that initiating adhesion is the harshest challenge for meningococci. The high abundance of the glutamate dehydrogenase (GdhA) and Opa1800 proteins in all bacterial isolates suggests their essential role in bacterial survival in vivo. To evaluate the biological relevance of our proteomic findings, four candidate proteins from representative functional groups, such as the bacterial chaperone GroEL, IMP dehydrogenase GuaB, and membrane proteins PilQ and NMC0101, were selected and their impact on bacterial fitness was investigated by mutagenesis assays. This study provides an integrated picture of bacterial niche-specific adaptations during consecutive infection processes.
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| 152455. |
- Liu, Ye, et al.
(författare)
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ECOVIBE : On-Demand Sensing for Railway Bridge Structural Health Monitoring
- 2019
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Ingår i: IEEE Internet of Things Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 2327-4662. ; 6:1, s. 1068-1078
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Tidskriftsartikel (refereegranskat)abstract
- Energy efficient sensing is one of the main objectives in the design of networked embedded monitoring systems. However, existing approaches such as duty cycling and ambient energy harvesting face challenges in railway bridge health monitoring applications due to the unpredictability of train passages and insufficient ambient energy around bridges. This paper presents ECOVIBE (Eco-friendly Vibration), an on-demand sensing system that automatically turns on itself when a train passes on the bridge and adaptively powers itself off after finishing all tasks. After that, it goes into an inactive state with near-zero power dissipation. ECOVIBE achieves these by: Firstly, a novel, fully passive event detection circuit to continuously detect passing trains without consuming any energy. Secondly, combining train-induced vibration energy harvesting with a transistor-based load switch, a tiny amount of energy is sufficient to keep ECOVIBE active for a long time. Thirdly, a passive adaptive off control circuit is introduced to quickly switch off ECOVIBE. Also this circuit does not consume any energy during inactivity periods. We present the prototype implementation of the proposed system using commercially available components and evaluate its performance in real-world scenarios. Our results show that ECOVIBE is effective in railway bridge health monitoring applications.
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| 152456. |
- Liu, Yawen, et al.
(författare)
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Efficient and Stable FAPbBr(3) Perovskite Solar Cells via Interface Modification by a Low-Dimensional Perovskite Layer
- 2021
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Ingår i: ACS Applied Energy Materials. - : American Chemical Society (ACS). - 2574-0962. ; 4:9, s. 9276-9282
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Tidskriftsartikel (refereegranskat)abstract
- Lead bromide perovskite with high bandgap and good stability has aroused broad interest for utilization in perovskite solar cells (PSCs) with high photovoltage, especially as a candidate for the front cell of tandem solar cells. However, the efficiency of lead bromide PSCs is still much lower than the standard lead iodide PSCs, and the defects in the perovskite are one of the main limiting factors hindering device performance. The construction of a 2D/3D perovskite interface is an effective way to passivate the interfacial defects and achieve efficient and stable PSCs. Herein, a facile and effective phenethylammonium bromide (PEABr) treatment method was applied to build a 2D/3D perovskite interface in FAPbBr(3) solar cells. An ultrathin layer of 2D PEA(2)PbBr(4) perovskite was successfully fabricated on the surface of 3D FAPbBr(3) perovskite by depositing the PEABr solution on the 3D perovskite films. The 2D perovskite layer significantly passivated the interfacial defects, leading to enhancement of power conversion efficiency from 7.7% to 9.4% and fill factor from 67.6% to 77.6%. Moreover, the hydrophobic alkyl chain in the PEA cation improved the moisture tolerance of the perovskite and significantly increases the solar cell stability. Additionally, the PEABr treatment strategy was successfully utilized for preparing semitransparent 2D/3D FAPbBr(3) perovskite solar cells.
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| 152457. |
- Liu, Yu, et al.
(författare)
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Ensemble Learning-Based Atrial Fibrillation Detection From Single Lead ECG Wave for Wireless Body Sensor Network
- 2023
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Ingår i: IEEE Transactions on Network Science and Engineering. - : Institute of Electrical and Electronics Engineers (IEEE). - 2327-4697. ; 10:5, s. 2627-2636
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Tidskriftsartikel (refereegranskat)abstract
- With the popularity of wireless techniques and portable devices, continuous and real-time monitoring patient’s health status by collecting physiological signals is becoming more popular. Data mining of electrocardiograph (ECG) attracts widespread attention, where automatic atrial fibrillation (AF) detection has become a hot research field. In this paper, an ensemble learning algorithm is proposed for AF detection from single lead ECG recordings collected by wearable devices. This algorithm includes two modules. First, denoised 1-D time series (ECG), time-frequency spectrum and Poincare plot are used to train three component learners through a parallel style, respectively, and each component learner produces four probability values. Then, all the outputs are combined using a weighted matrix constructed by a Bayesian optimization algorithm, which is capable of producing the final classification result. Quantities of experiments have been implemented, and the results well prove the algorithm’s effectiveness and its advantage over some state-of-the-art counterparts.
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| 152458. |
- Liu, Yang, et al.
(författare)
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Environmental factors influence both abundance and genetic diversity in a widespread bird species
- 2013
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 3:14, s. 4683-4695
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Tidskriftsartikel (refereegranskat)abstract
- Genetic diversity is one of the key evolutionary variables that correlate with population size, being of critical importance for population viability and the persistence of species. Genetic diversity can also have important ecological consequences within populations, and in turn, ecological factors may drive patterns of genetic diversity. However, the relationship between the genetic diversity of a population and how this interacts with ecological processes has so far only been investigated in a few studies. Here, we investigate the link between ecological factors, local population size, and allelic diversity, using a field study of a common bird species, the house sparrow (Passer domesticus). We studied sparrows outside the breeding season in a confined small valley dominated by dispersed farms and small-scale agriculture in southern France. Population surveys at 36 locations revealed that sparrows were more abundant in locations with high food availability. We then captured and genotyped 891 house sparrows at 10 microsatellite loci from a subset of these locations (N=12). Population genetic analyses revealed weak genetic structure, where each locality represented a distinct substructure within the study area. We found that food availability was the main factor among others tested to influence the genetic structure between locations. These results suggest that ecological factors can have strong impacts on both population size per se and intrapopulation genetic variation even at a small scale. On a more general level, our data indicate that a patchy environment and low dispersal rate can result in fine-scale patterns of genetic diversity. Given the importance of genetic diversity for population viability, combining ecological and genetic data can help to identify factors limiting population size and determine the conservation potential of populations.
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| 152459. |
- Liu, Yage, et al.
(författare)
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Estimating the impact of shelterbelt structure on corn yield at a large scale using Google Earth and Sentinel 2 data
- 2022
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 17:4
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Tidskriftsartikel (refereegranskat)abstract
- A shelterbelt is an important measure to protect farmland and increase crop yield. However, how a shelterbelt structure affects crop yield is still unclear due to the difficulties accessing sufficient data from traditional field observations. To address this problem, we developed an innovative framework to estimate the shelterbelt structure and crop yield profile at a regional scale based on Google Earth and Sentinel-2 data. Using this method, we quantified the impact of the shelterbelt structure on the corn yield at 302 shelterbelts in the Northeast Plain of China. Generally, the corn yield increased (by 2.41% on average) within a distance of 1.2-15 times the tree height from the shelterbelt. Such an effect was particularly prominent within a distance of two to five times the tree height, where the corn yield was significantly increased by up to 4.63%. The structure of the shelterbelt has a significant effect on the magnitude of increase in yield of the surrounding corn. The increment of corn yields with high-, medium-high-, medium- and low-width-gap grade shelterbelt were 2.01%, 2.21%, 1.99%, and 0.91%, respectively. The medium-high grade shelterbelt achieved the largest yield increase effect. The location of the farmland relative to the shelterbelt also affected the yield, with a yield increase of 2.39% on the leeward side and 1.89% on the windward side, but it did not change the relationship between the yield increase effect and the shelterbelt structure. Our findings highlight the optimal shelterbelt structure for increasing corn yield, providing practical guidance on the design and management of farmland shelterbelts for maximizing yield.
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| 152460. |
- Liu, Yage, et al.
(författare)
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Estimating the Legacy Effect of Post-Cutting Shelterbelt on Crop Yield Using Google Earth and Sentinel-2 Data
- 2022
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Ingår i: Remote Sensing. - : MDPI AG. - 2072-4292. ; 14:19
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Tidskriftsartikel (refereegranskat)abstract
- Shelterbelts (or windbreaks) can effectively improve the microclimate and soil conditions of adjacent farmland and thus increase crop yield. However, the individual contribution of these two factors to yield changes is still unclear since the short-term effect from the microclimate and the accumulated effect from the soil jointly affect crop yield. The latter (soil effect) is supposed to remain after shelterbelt-cutting, thus inducing a post-cutting legacy effect on yield, which can be used to decompose the shelterbelt-induced yield increase. Here, we develop an innovative framework to investigate the legacy effect of post-cutting shelterbelt on corn yield by combining Google Earth and Sentinel-2 data in Northeastern China. Using this framework, for the first time, we decompose the shelterbelt-induced yield increase effect into microclimate and soil effects by comparing the yield profiles before and after shelterbelt-cutting. We find that on average, the intensity of the legacy effect, namely the crop yield increment of post-cutting shelterbelts, is 0.98 ± 0.03%. The legacy effect varies depending on the shelterbelt–farmland relative location and shelterbelt density. The leeward side of the shelterbelt-adjacent farmland has a more remarkable legacy effect compared to the windward side. Shelterbelts with medium–high density have the largest legacy effect (1.94 ± 0.05%). Overall, the legacy effect accounts for 47% of the yield increment of the shelterbelt before cutting, implying that the soil effect is almost equally important for increasing crop yield compared to the microclimate effect. Our findings deepen the understanding of the mechanism of shelterbelt-induced yield increase effects and can help to guide shelterbelt management.
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