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Time-history performance optimization of flapping wing motion using a deep learning based prediction model

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Chinese Journal of Aeronautics 2024年第5期37卷 317-331页

作者： Tianqi WANG Liu LIU Jun LI Lifang ZENG School of Aeronautics and Astronautics Zhejiang UniversityHangzhou 310027China Huanjiang Laboratory Zhuji 311800China

Flapping Wing Micro Aerial Vehicles(FWMAVs)have caused great concern in various fields because of their high efficiency and *** wing motion is a very important factor that affects the performance of the aircraft,and previous works have always focused on the time-averaged performance ***,the time-history performance is equally important in the design of motion mechanism and flight control *** this paper,a time-history performance optimization framework based on deep learning and multi-island genetic algorithm is presented,which is designed in order to obtain the optimal two-dimensional flapping wing ***,the training dataset for deep learning neural network is constructed based on a validated computational fluid dynamics *** aerodynamic surrogate model for flapping wing is obtained after the convergence of *** surrogate model is tested and proved to be able to accurately and quickly predict the time-history curves of lift,thrust and ***,the optimization framework is used to optimize the flapping wing motion in two specific cases,in which the optimized propulsive efficiencies have been improved by over 40%compared with the ***,a dimensionless parameter C_(variation)is proposed to describe the variation of the time-history characteristics,and it is found that C_(variation)of lift varies significantly even under close time-averaged *** the importance of time-history performance in practical applications,the optimization that integrates the propulsion efficiency as well as C_(variation)is carried *** final optimal flapping wing motion balances good time-averaged and time-history performance.

关键词： FWMAV Flapping wing motion Deep learning Unsteady aerodynamic performance Optimization Time-history curve

Engineered extracellular vesicles for targeted reprogramming of cancer-associated fibroblasts to potentiate therapy of pancreatic cancer

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Signal Transduction and Targeted Therapy 2024年第7期9卷 3077-3096页

作者： Pengcheng Zhou Xuanlong Du Weilu Jia Kun Feng Yewei Zhang Department of General Surgery Affiliated Hospital of Nantong UniversityNantongChina School of Medicine Southeast UniversityNanjingChina Nanjing Medical University NanjingChina Hepatobiliary and Pancreatic Center The Second Affiliated Hospital of Nanjing Medical UniversityNanjingChina

Pancreatic cancer is one of the deadly malignancies with a significant mortality rate and there are currently few therapeutic options for *** tumor microenvironment(TME)in pancreatic cancer,distinguished by fibrosis and the existence of cancer-associated fibroblasts(CAFs),exerts a pivotal influence on both tumor advancement and resistance to *** advancements in the field of engineered extracellular vesicles(EVs)offer novel avenues for targeted therapy in pancreatic *** study aimed to develop engineered EVs for the targeted reprogramming of CAFs and modulating the TME in pancreatic *** obtained from bone marrow mesenchymal stem cells(BMSCs)were loaded with miR-138-5p and the anti-fibrotic agent pirfenidone(PFD)and subjected to surface modification with integrinα5-targeting peptides(named IEVs-PFD/138)to reprogram CAFs and suppress their pro-tumorigenic ***α5-targeting peptide modification enhanced the CAF-targeting ability of ***-138-5p directly inhibited the formation of the FERMT2-TGFBR1 complex,inhibiting TGF-βsignaling pathway *** addition,miR-138-5p inhibited proline-mediated collagen synthesis by directly targeting the FERMT2-PYCR1 *** combination of miR-138-5p and PFD in EVs synergistically promoted CAF reprogramming and suppressed the pro-cancer effects of *** experiments using the orthotopic stroma-rich and patient-derived xenograft mouse models yielded promising *** particular,IEVs-PFD/138 effectively reprogrammed CAFs and remodeled TME,which resulted in decreased tumor pressure,enhanced gemcitabine perfusion,tumor hypoxia amelioration,and greater sensitivity of cancer cells to ***,the strategy developed in this study can improve chemotherapy *** IEVs-PFD/138 as a targeted therapeutic agent to modulate CAFs and the TME represents a promising therapeutic approach for pancreatic cancer.

关键词： inhibited targeted chemotherapy

水电梯级开发真的破坏下游河段营养盐情势吗?

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Science Bulletin 2024年第5期69卷 661-670页

作者：陈求稳陈宇琛林育青张建云倪晋仁夏军肖琳冯韬马宏海 State Key Laboratory of Hydrology-Water Resources&Hydraulic Engineering Nanjing Hydraulic Research InstituteNanjing 210029China Center for Eco-Environment Research Nanjing Hydraulic Research InstituteNanjing 210029China Yangtze Institute for Conservation and Green development Nanjing 210024China School of the Environment Nanjing UniversityNanjing 210008China The Key Laboratory of Water and Sediment Sciences Ministry of EducationPeking UniversityBeijing 100091China State Key Laboratory of Water Resources and Hydropower Engineering Sciences Wuhan UniversityWuhan 430072China

River damming is believed to largely intercept nutrients,particularly retain more phosphorus(P)than nitrogen(N),and thus harm primary productivity,fishery catches,and food security downstream,which seriously constrain global hydropower development and poverty relief in undeveloped regions and can drive geo-political disputes between nations along trans-boundary *** this study,we investigated whether reservoirs can instead improve nutrient regimes *** measured different species of N and P as well as microbial functions in water and sediment of cascade reservoirs in the upper Mekong River over 5 years and modelled the influx and outflux of N and P species in each *** partially retaining total N and total P,reservoirs increased the downstream flux of ammonium and soluble reactive phosphorus(SRP).The increase in ammonium and SRP between outflux and influx showed positive linear relationships with the hydraulic residence time of the cascade reservoirs;and the ratio of SRP to dissolved inorganic nitrogen increased along the reservoir *** lentic environment of reservoirs stimulated algae-mediated conversion of nitrate into ammonium in surface water;the hypoxic condition and the priming effect of algae-induced organic matter enhanced release of ammonium from sediment;the synergy of microbial phosphorylation,reductive condition and sediment geochemical properties increased release of *** study is the first to provide solid evidence that hydropower reservoirs improve downstream nutrient bioavailability and N-P balance through a process of retention-transformation-transport,which may benefit primary *** findings could advance our understanding of the eco-environmental impacts of river damming.

关键词： River damming Biogeochemical cycle Nitrogen Phosphorus Ecological impacts

UDT:U-shaped deformable transformer for subarachnoid haemorrhage image segmentation

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CAAI Transactions on Intelligence Technology 2024年第3期9卷 756-768页

作者： Wei Xie Lianghao Jin Shiqi Hua Hao Sun Bo Sun Zhigang Tu Jun Liu Hubei Provincial Key Laboratory of Artificial Intelligence and Smart Learning Central China Normal UniversityWuhanChina School of Computer Science Central China Normal UniversityWuhanChina National Language Resources Monitoring and Research Center for Network Media Central China Normal UniversityWuhanChina The First Affiliated Hospital of Dalian Medical University DalianChina State Key Laboratory of Information Engineering in Surveying Mapping and Remote SensingWuhan UniversityWuhanChina Information Systems Technology and Design Pillar Singapore University of Technology and DesignSingaporeSingapore

Subarachnoid haemorrhage(SAH),mostly caused by the rupture of intracranial aneu-rysm,is a common disease with a high fatality *** lesions are generally diffusely distributed,showing a variety of scales with irregular *** complex characteristics of lesions make SAH segmentation a challenging *** cope with these difficulties,a u-shaped deformable transformer(UDT)is proposed for SAH ***,first,a multi-scale deformable attention(MSDA)module is exploited to model the diffuseness and scale-variant characteristics of SAH lesions,where the MSDA module can fuse features in different scales and adjust the attention field of each element dynamically to generate discriminative multi-scale ***,the cross deformable attention-based skip connection(CDASC)module is designed to model the irregular edge char-acteristic of SAH lesions,where the CDASC module can utilise the spatial details from encoder features to refine the spatial information of decoder ***,the MSDA and CDASC modules are embedded into the backbone Res-UNet to construct the proposed *** experiments are conducted on the self-built SAH-CT dataset and two public medical datasets(GlaS and MoNuSeg).Experimental results show that the presented UDT achieves the state-of-the-art performance.

关键词： image segmentation medical image processing

Polyoxometalates coupled covalent organic frameworks as highly active photothermal nanoreactor for CO_(2)cycloaddition

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Nano Research 2024年第7期17卷 5975-5984页

作者： Tian Wang Yunqing Zhu Wei Wang Junfeng Niu Zhiyi Lu Peilei He School of Environmental Science and Engineering Shaanxi University of Science and TechnologyXi’an 710021China Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201China College of Environmental Science and Engineering North China Electric Power UniversityBeijing 102206China University of Chinese Academy of Sciences Beijing 100049China

Covalent organic frameworks(COFs)-based nanoreactors have attracted broad interest in many fields due to their voidconfinement ***,the inherent drawback of conventional nanoreactors is the lack of internal active sites,which limits their widespread ***,we report the construction of hierarchical COF(EB-TFP)nanoreactor with pre-synthesized polyoxometalates(POM,[PV_(2)W_(10)O40]5–(PV_(2)W_(10)))clusters encapsulated inside of COF(POM@COF).PV_(2)W_(10)@EB-TFP anchors nucleophilic-group(Br–ions)and PV_(2)W_(10)anion cluster within the COF framework via electrostatic interactions,which not only simplifies the reaction system but also enhances catalytic *** reaction performance of the PV_(2)W_(10)@EB-TFP nanoreactor can be tuned to achieve excellent catalytic activity in CO_(2)cycloaddition reaction(CCR)for~97.63%conversion and~100%selectivity under visible light irradiation.A mechanistic study based on density functional theory(DFT)calculations and insitu characterization was also carried *** summary,we have reported a method for achieving the uniform dispersion of POM single clusters into COF nanoreactor,demonstrating the potential of POM@COF nanoreactor for synergistic photothermal catalytic CO_(2)cycloaddition.

关键词： photothermal nanoreactor CO_(2)cycloaddition polyoxometalate photothermal-synergistic catalysis covalent organic frameworks

Dynamics of ecosystems and anthropogenic drivers in the Yellow Sea Large Marine Ecosystem

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Acta Oceanologica Sinica 2022年第6期41卷 1-3页

作者： Jun Sun Yinfeng Guo Gyung Soo Park Andrew Hudson Institute for Advanced Marine Research China University of GeosciencesGuangzhou 511462China National Marine Hazard Mitigation Service Ministry of Natural ResourcesBeijing 100194China Department of Marine Biotechnology Anyang UniversityAnyang 14028R.O.Korea Bureau for Policy and programme Support United Nations Development ProgrammeNew York 10017USA

In the developed world,governance of marine ecological environment is the important part of the national ecological and economic *** Yellow Sea is one of large marine ecosystems in the seas of East Asia,which is an extension of one of the largest continental shelf areas,and forms a huge but shallow sediment body in its south area which is geographically unique in the *** a region with the most fragile natural environment,unparalleled global ecological significance and the most urgent protection needs,the Yellow Sea ecological zone is becoming a common concern of countries around the Yellow Sea and beyond,such as tidal flats and the staging migratory birds(Murray et al.,2015).

关键词： shallow tidal shelf

Polyp-Canal Reconstruction Reveals Evolution Toward Complexity in Corals

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Research 2024年第1期2023卷 417-428页

作者： Yixin Li Xin Liao Xin Wang Yuanchao Li Hongwei Zhao Yunpeng Zhao Junyuan Chen Chunpeng He Zuhong Lu State Key Laboratory of Bioelectronics School of Biological Science and Medical EngineeringSoutheast UniversityNanjing 210096China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China Guangxi Key Lab of Mangrove Conservation and Utilization Guangxi Mangrove Research CenterGuangxi Academy of SciencesBeihai 536000China Hainan Academy of Ocean and Fishery Sciences Haikou 571126China State Key Laboratory of Marine Resources Utilization in South china Sea Hainan UniversityHaikou 570228China Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences39 East Beijing RoadNanjing 210008China

Modern scleractinian corals are classified into robust,complex,and basal clades through comparative molecular ***,only few morphological or biological criteria can systematically determine the evolutionary trajectories of these major scleractinian coral ***,we obtained the structural information of 21 scleractinian coral species representing robust and complex clades:High-resolution micro-computed tomography was used to reconstruct the polyp-canal systems in their colonies and to visualize the dynamic polyp growth *** found that the emergence of mesh-like canals may distinguish representatives of complex and robust *** differences in polyp-canal connections suggest distinct evolutionary trajectories among coral species:The formation of the canal network promoted the development of more complex coral structures,and coral polyps within this network formed calices of very similar volume,following precise axial growth *** influence of individual polyps on the coral colony becomes less significant as coral structures become more complex,and coral species with more complicated polyp-canal systems occupied niches more *** work supplements current evolutionary studies on reef-building corals,providing insight for further studies on coral growth patterns.

关键词： Coral representing directions

UAV-Assisted Dynamic Avatar Task Migration for Vehicular Metaverse Services: A Multi-Agent Deep Reinforcement Learning Approach

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 430-445页

作者： Jiawen Kang Junlong Chen Minrui Xu Zehui Xiong Yutao Jiao Luchao Han Dusit Niyato Yongju Tong Shengli Xie IEEE School of Automation Guangdong University of TechnologyGuangzhou 510006China 111 Center for Intelligent Batch Manufacturing based on IoT Technology Guangzhou 510006China Key Laboratory of Intelligent Information Processing and System Integration of IoT Ministry of EducationGuangzhou 510006China School of Computer Science and Engineering Nanyang Technological UniversitySingaporeSingapore Pillar of Information Systems Technology and Design Singapore University of Technology and DesignSingaporeSingapore College of Communication Engineering Army Engineering University of PLANanjing 210007China National Natural Science Foundation of china Beijing 100085China Key Laboratory of Intelligent Detection and IoT in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong Key Laboratory of IoT Information Technology Guangzhou 510006China

Avatars, as promising digital representations and service assistants of users in Metaverses, can enable drivers and passengers to immerse themselves in 3D virtual services and spaces of UAV-assisted vehicular Metaverses. However, avatar tasks include a multitude of human-to-avatar and avatar-to-avatar interactive applications, e.g., augmented reality navigation,which consumes intensive computing resources. It is inefficient and impractical for vehicles to process avatar tasks locally. Fortunately, migrating avatar tasks to the nearest roadside units(RSU)or unmanned aerial vehicles(UAV) for execution is a promising solution to decrease computation overhead and reduce task processing latency, while the high mobility of vehicles brings challenges for vehicles to independently perform avatar migration decisions depending on current and future vehicle status. To address these challenges, in this paper, we propose a novel avatar task migration system based on multi-agent deep reinforcement learning(MADRL) to execute immersive vehicular avatar tasks dynamically. Specifically, we first formulate the problem of avatar task migration from vehicles to RSUs/UAVs as a partially observable Markov decision process that can be solved by MADRL algorithms. We then design the multi-agent proximal policy optimization(MAPPO) approach as the MADRL algorithm for the avatar task migration problem. To overcome slow convergence resulting from the curse of dimensionality and non-stationary issues caused by shared parameters in MAPPO, we further propose a transformer-based MAPPO approach via sequential decision-making models for the efficient representation of relationships among agents. Finally, to motivate terrestrial or non-terrestrial edge servers(e.g., RSUs or UAVs) to share computation resources and ensure traceability of the sharing records, we apply smart contracts and blockchain technologies to achieve secure sharing management. Numerical results demonstrate that the proposed approach

关键词： Avatar blockchain metaverses multi-agent deep reinforcement learning transformer UAVs

Unveiling the chemistry behind the electrolytic production of hydrogen peroxide by oxygenated carbon

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Journal of Energy Chemistry 2024年第9期96卷 49-58页

作者： Pan Xiang Kunshang Yang Qihao Yang Yang Gao Wenwen Xu Zhiyi Lu Liang Chen Zhiming Wang Ziqi Tian Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu 610054SichuanChina Key Laboratory of Advanced Fuel Cells and Electrolyzers Technology of Zhejiang Province Ningbo Institute of Materials Technology and EngineeringChinese Academy of SciencesNingbo 315201ZhejiangChina Institute for Advanced Study Chengdu UniversityChengdu 610106SichuanChina

Oxygenated carbon materials exhibit outstanding electrocatalytic performance in the production of hydrogen peroxide(H2O2)through a two-electron oxygen reduction *** nature of the active functional group and underlying reaction mechanism,however,remain ***,a comprehensive workflow was established to identify the active sites from the numerous possible *** common hydroxyl group at the notched edge demonstrates a key role in the two-electron *** local chemical environment weakens the binding of OOH intermediate to substrate while enhancing interaction with solution,thereby promoting the H_(2)O_(2)*** increasing pH,the intramolecular hydrogen bond between OOH intermediate and hydroxyl decreases,facilitating OOH ***,the rise in selectivity with increasing potential stems from the suppression of the four-electron *** active site was further validated through *** by theoretical understanding,optimal performance was achieved with high selectivity(>95%)and current density(2.06 mA/cm^(2))in experiment.

关键词： First-principles calculation Oxygen reductionreaction Hydrogen peroxide production Fixed-potential method Oxygenated carbon materials