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Atomic interface regulation of rare-marth metal single atom catalysts for energy conversion

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Nano Research 2024年第5期17卷 3493-3515页

作者： ziheng zhan Zhiyi Sun zihao Wei Yaqiong li Wenxing Chen Shenghua li Siping Pang School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China

Efficient photocatalysis and electrocatalysis in energy conversion have been important strategies to alleviate energy crises and environmental *** recent years,with the rapid development of emerging catalysts,significant progress has been made in photocatalysis for converting solar energy into chemical energy and electrocatalysis for converting electrical energy into chemical ***,their selectivity and efficiency of the products are *** earth(RE)can achieve atomic level fine regulation of catalysts and play an crucial role in optimizing catalyst performance by their unique electronic and orbital ***,there is a lack of systematic review on the atomic interface regulation mechanism of RE and their role in energy conversion *** atom catalysts(SACs)provide clear active sites and 100%atomic utilization,which is conducive to exploring the regulatory mechanisms of ***,this review mainly takes atomic level doped RE as an example to review and discuss the atomic interface regulation role of RE elements in energy ***,a brief introduction was given to the synthesis strategies that can effectively exert the atomic interface regulation effect of RE,with a focus on the atomic interface regulation mechanism of ***,the regulatory mechanisms of RE atoms have been systematically summarized in various energy conversion ***,the challenges faced by RE in energy conversion,as well as future research directions and prospects,were pointed out.

关键词： rare earth elements interface regulation effect single-atom catalyst energy conversion

Recent Advances in Interface Modification of Cu/graphite Composites and Layered Ternary Carbides of Modified Layer Candidate

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Journal of Wuhan University of Technology(Materials Science) 2024年第5期39卷 1061-1072页

作者： WEI Hongming li Mingchao li Xiaoya zhan Wenyi li Feiyang DAI Yanzhang ZOU Jianpeng State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Guangxi Fangchenggang Nuclear Power Co. Ltd.Fangchenggang 538000China

We review the fundamental properties and significant issues related to Cu/graphite *** particular,recent research on the interfacial modification of Cu/graphite composites is addressed,including the metal-modified layer,carbide-modified layer,and combined modified ***,we propose the use of ternary layered carbide as an interface modification layer for Cu/graphite composites.

关键词： Cu/graphite composites interfacial bonding surface modification wettability layered ternary carbides

Numerical simulation of aircraft arresting process with an efficient full-scale rigid-flexible coupling dynamic model

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Chinese Journal of Aeronautics 2024年第5期37卷 586-602页

作者： Haoyuan SHAO Daochun li zi KAN Lanxi BI Zhuoer YAO Jinwu XIANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Tianmushan Laboratory Hangzhou 310023China

The arresting process of carrier-based aircraft is widely recognized as a challenging task,characterized by the highest accident rate among all carrier-based aircraft *** simulation plays a crucial role in assessing the intricate responses of the arresting process,favoring the design of carrier-based *** efficient and accurate rigid-flexible coupling model for analyzing the dynamic response of the arresting process is *** combining the dynamic characteristics of airframe,landing gear,arresting hook and arresting gear system,the rigid-flexible coupling dynamic model is established to reflect the relative motion of the coupling parts and arresting *** dynamic model is verified through simulations of landing gear landing drops and by comparing the arresting simulation results with corresponding data in the US military ***,simulations of the arresting process under different off-center distance and aircraft yaw angle are conducted to obtain the dynamic response of the aircraft during the arresting *** result indicates that the rigid-flexible coupling dynamic model proposed is effective for analyzing the arresting dynamics response of carrier-based *** axial force of the arresting cable on both sides of the hook engagement point,pitch and yaw angle of aircraft are inconsistent under yaw and off-center *** analysis method and obtained results provide valuable references for assessing the dynamic responses of carrier-based aircraft during arresting process and offer valuable in-sights in the design of carrier-based aircraft.

关键词： Carrier-based aircraft Deck landing Rigid-flexible coupling dynamic model Finite element method Dynamic analysis

Chain Dynamics Heterogeneity in Plasticized Poly(vinyl butyral)(PVB) as Elucidated by Solid-State NMR

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Chinese Journal of Polymer Science 2024年第1期42卷 113-124,I0010页

作者： Jing Lv Xu Chen zi-Shuo Wu Ya-Hui li Wei Chen National Synchrotron Radiation Laboratory Anhui Provincial Engineering Laboratory of Advanced Functional Polymer FilmCAS Key Laboratory of Soft Matter ChemistryUniversity of Scienceand Technology of ChinaHefei 230026China

The chain dynamics heterogeneity of the poly(vinyl butyral)(PVB) plasticized by triethylene glycol bis(2-ethylhexa noate)(TEG-EH) was investigated by various solid-state NMR *** plasticized PVB shows two domains in distinct molecular dynamics differences,namely,rigid and soft domains,where the latter is the plasticizer-rich *** time domain low field NMR was first used to investigate the dynamics heterogeneity of the plasticized PVB,and the results show the decreasing activated energy of components in the soft domain of plasticized PVB(E_a=20.2 kJ/mol) as compared with that of the pristine one(E_a=24.3 kJ/mol).Detailed dynamics heterogeneity was obtained by high-field NMR with site-specific *** quadrupole-echo ~2H-NMR was adopted to elucidate the dynamics heterogeneity of the vinyl alcohol(VA) units,where only the hydroxyl group of VA is *** ~1H-^(13)C WISE NMR spectra show that there is not much difference in the mobility of the VB unit in PVB with and without plasticizer,whereas the glass transition temperature differed by approximately 53℃.This is further supported by Torchia's T_1 relaxation *** origin of such an unusual phenomenon is attributed to the critical role of the remaining VA(~22%) in the soft domain,where the VA units locally aggregate through hydrogen ***,the existence of a mobility gradient in the VB unit has been ***,the mobility difference for VB with different stereo-geometry(meso or racemic conformation) is observed for the first *** indicates the importance of modulating the ratio of meso over racemic VB for controlling the macroscopic perfo rmance of PVB.

关键词： Poly(vinyl butyral) Dynamics heterogeneity Plasticizer Solid state NMR

UAV maneuvering decision-making algorithm based on deep reinforcement learning under the guidance of expert experience

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Journal of Systems Engineering and Electronics 2024年第3期35卷 644-665页

作者： zhan Guang zhanG Kun li Ke PIAO Haiyin School of Electronics and Information Northwestern Polytechnical UniversityXi’an 710072China Science and Technology on Electro-Optic Control Laboratory Luoyang 471009China

Autonomous umanned aerial vehicle(UAV) manipulation is necessary for the defense department to execute tactical missions given by commanders in the future unmanned battlefield. A large amount of research has been devoted to improving the autonomous decision-making ability of UAV in an interactive environment, where finding the optimal maneuvering decisionmaking policy became one of the key issues for enabling the intelligence of UAV. In this paper, we propose a maneuvering decision-making algorithm for autonomous air-delivery based on deep reinforcement learning under the guidance of expert experience. Specifically, we refine the guidance towards area and guidance towards specific point tasks for the air-delivery process based on the traditional air-to-surface fire control ***, we construct the UAV maneuvering decision-making model based on Markov decision processes(MDPs). Specifically, we present a reward shaping method for the guidance towards area and guidance towards specific point tasks using potential-based function and expert-guided advice. The proposed algorithm could accelerate the convergence of the maneuvering decision-making policy and increase the stability of the policy in terms of the output during the later stage of training process. The effectiveness of the proposed maneuvering decision-making policy is illustrated by the curves of training parameters and extensive experimental results for testing the trained policy.

关键词： unmanned aerial vehicle(UAV) maneuvering decision-making autonomous air-delivery deep reinforcement learning reward shaping expert experience

Anomalous response to creep deformation from dislocation density during electrically assisted creep aging

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Rare Metals 2024年第10期43卷 5268-5283页

作者： Chang Zhou li-Hua zhan Chun-Hui liu Ming-Hui Huang College of Mechanical and Electrical Engineering Central South University light Alloys Research Institute State Key Laboratory of Precision Manufacturing for Extreme Service PerformanceCentral South University

Adding numerous dislocations into metallic materials before the forming stage significantly enhances their deformability. However, this beneficial effect of dislocation defects may not have a simple monotonic relationship with increased dislocation density during electroplastic deformation. This is due to the complex interactions among the drifting electrons, dislocations and solute atoms. This study explores the effect of diverse initial dislocation densities on creep deformation during electrically aided creep aging of an aluminum–lithium alloy. Surprisingly, we discovered a threshold value for the dislocation density that affects electroplastic creep, i.e., an enhanced effect from dislocations weakens when exceeding this density threshold(an anomalous response to creep). Microstructural data also reveal that such an anomalous response originates mainly from differences in various dislocation density-tailored configurations, which can influence the dislocation motions and precipitation kinetics of the strengthening T1precipitates under the same action of pulsed currents. This study provides important insights into the dislocation density-mediated electroplastic creep of an aluminum–lithium alloy.

关键词： Al–Cu–li alloy Creep aging Dislocation density Pulsed currents

Microplastic exposure disturbs sleep structure,reduces lifespan,and decreases ovary size in Drosophila melanogaster

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Zoological Research 2024年第4期45卷 805-820页

作者： Wei Yan zi-Jie li zi-Yi lin Shu-Qin Ji William Ka Fai Tse Zhi-Qiang Meng Chang liu Lei li Shenzhen-Hong Kong Institute of Brain Science Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China CAS Key Laboratory of Brain Connectome and Manipulation the Brain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China Laboratory of Developmental Disorders and Toxicology Center for Promotion of International Education and ResearchFaculty of AgricultureKyushu UniversityFukuokaFukuoka 819-0395Japan Shenzhen Key Laboratory of Drug Addiction the Brain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China Guangdong Provincial Key Laboratory of Brain Connectome and Behavior Brain Cognition and Brain Disease InstituteShenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhenGuangdong 518000China

The organ-specific toxicity resulting from microplastic(MP)exposure has been extensively explored,particularly concerning the gut,liver,testis,and ***,under natural conditions,these effects are not restricted to specific organs or *** whether MP exposure presents a systemic threat to an entire organism,impacting factors such as lifespan,sleep,and fecundity,is *** this study,we investigated the effects of dietary exposure to two different doses of MPs(1–5μm)using the terrestrial model organism Drosophila *** indicated that the particles caused gut damage and remained within the digestive *** MP exposure significantly shortened the lifespan of adult *** short-term exposure disrupted sleep patterns,increasing the length of daytime sleep ***,one week of MP exposure reduced ovary size,with a trend towards decreased egg-laying in mated *** MPs did not penetrate the brain or ovaries,transcriptome analysis revealed altered gene expression in these *** the ovary,Gene Ontology(GO)analysis indicated genotoxic effects impacting inflammation,circadian regulation,and metabolic processes,with significant impacts on extracellular structure-related *** the brain,GO analysis identified changes in pathways associated with proteolysis and carbohydrate ***,this study provides compelling evidence of the systemic negative effects of MP exposure,highlighting the urgent need to address and mitigate environmental MP pollution.

关键词： Microplastics Sleep lifespan Reproduction Risk assessment Drosophila melanogaster

A study of the effect of local scour on the flow field near the spur dike

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Theoretical & Applied Mechanics Letters 2024年第2期14卷 98-105页

作者： Yu-Tian li Jie-Min zhan Wing-Hong Onyx Wai Department of Industrial Design School of Industrial Design and Ceramic ArtFoshan UniversityFoshan 528000China Department of Applied Mechanics and Engineering Shenzhen Campus of Sun Yat-sen UniversityShenzhen 518107China Department of Civil and Environmental Engineering The Hong Kong Polytechnic UniversityHong Kong 999077China

The flow field near a spur dike such as down flow and horseshoe vortex system(HVS)are susceptible to the topographic changes in the local scouring process,resulting in variation of the sediment transport with *** this study,large eddy simulations with fixed-bed at different scouring stages were conducted to investigate the changes in flow *** results imply that the bed deformation leads to an increase in flow rate per unit area,which represent the capability of sediment transportation by water,in the scour ***,the intensity of turbulent kinetic energy and bimodal motion near the sand bed induced by the HVS were also ***,the peak moments between the two sediment transport mechanisms were ***,understanding the complex feedback mechanism between topography and flow field is essential for the local scour problem.

关键词： Spur dike Local scour Large eddy simulation Down flow Horseshoe vortex system

Automated identification of steel weld defects,a convolutional neural network improved machine learning approach

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Frontiers of Structural and Civil Engineering 2024年第2期18卷 294-308页

作者： zhan SHU Ao WU Yuning SI Hanlin DONG Dejiang WANG Yifan li School of Mechanics and Engineering Science Shanghai UniversityShanghai 200444China School of Civil Engineering Shanghai Normal UniversityShanghai 201418China Shanghai PinlanData Technology Co. Ltd.Shanghai 200072China

This paper proposes a machine-learning-based methodology to automatically classify different types of steel weld defects,including lack of the fusion,porosity,slag inclusion,and the qualified(no defects)*** methodology solves the shortcomings of existing detection methods,such as expensive equipment,complicated operation and inability to detect internal *** study first collected percussed data from welded steel members with or without weld ***,three methods,the Mel frequency cepstral coefficients,short-time Fourier transform(STFT),and continuous wavelet transform were implemented and compared to explore the most appropriate features for classification of weld *** and convolutional neural network-enhanced algorithms were used to classify,the extracted ***,experiments were designed and performed to validate the proposed *** showed that STFT achieved higher accuracies(up to 96.63%on average)in the weld status *** convolutional neural network-enhanced support vector machine(SVM)outperformed six other algorithms with an average accuracy of 95.8%.In addition,random forest and SVM were efficient approaches with a balanced trade-off between the accuracies and the computational efforts.

关键词： steel weld machine learning convolutional neural network weld defect detection classification task percussion