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Missing Value Imputation for Radar-Derived Time-Series Tracks of Aerial Targets Based on Improved Self-Attention-Based Network

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Computers, Materials & Continua 2024年第3期78卷 3349-3376页

作者： Zihao Song yan Zhou Wei Cheng Futai liang Chenhao Zhang Department of Early Warning Intelligence Early Warning AcademyWuhan430019China

The frequent missing values in radar-derived time-series tracks of aerial targets(RTT-AT)lead to significant challenges in subsequent data-driven ***,the majority of imputation research focuses on random missing(RM)that differs significantly from common missing patterns of *** method for solving the RM may experience performance degradation or failure when applied to RTT-AT *** autoregressive deep learning methods are prone to error accumulation and long-term dependency *** this paper,a non-autoregressive imputation model that addresses the issue of missing value imputation for two common missing patterns in RTT-AT is *** model consists of two probabilistic sparse diagonal masking self-attention(PSDMSA)units and a weight fusion *** learns missing values by combining the representations outputted by the two units,aiming to minimize the difference between the missing values and their actual *** PSDMSA units effectively capture temporal dependencies and attribute correlations between time steps,improving imputation *** weight fusion unit automatically updates the weights of the output representations from the two units to obtain a more accurate final *** experimental results indicate that,despite varying missing rates in the two missing patterns,our model consistently outperforms other methods in imputation performance and exhibits a low frequency of deviations in estimates for specific missing *** to the state-of-the-art autoregressive deep learning imputation model Bidirectional Recurrent Imputation for Time Series(BRITS),our proposed model reduces mean absolute error(MAE)by 31%~50%.Additionally,the model attains a training speed that is 4 to 8 times faster when compared to both BRITS and a standard Transformer model when trained on the same ***,the findings from the ablation experiments demonstrate that the PSDMSA,the weight fusion unit,cascade network design

关键词： Missing value imputation time-series tracks probabilistic sparsity diagonal masking self-attention weight fusion

Neural stem cells promote neuroplasticity: a promising therapeutic strategy for the treatment of Alzheimer’s disease

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Neural Regeneration Research 2024年第3期19卷 619-628页

作者： Jun Chang Yujiao Li Xiaoqian Shan Xi Chen Xuhe yan Jianwei Liu lan Zhao First Teaching Hospital of Tianjin University of Traditional Chinese Medicine TianjinChina National Clinical Research Center for Chinese Medicine Acupuncture and Moxibustion TianjinChina Tianjin University of Traditional Chinese Medicine TianjinChina

Recent studies have demonstrated that neuroplasticity,such as synaptic plasticity and neurogenesis,exists throughout the normal lifespan but declines with age and is significantly impaired in individuals with Alzheimer’s ***,promoting neuroplasticity may represent an effective strategy with which Alzheimer’s disease can be *** to their significant ability to self-renew,differentiate,and migrate,neural stem cells play an essential role in reversing synaptic and neuronal damage,reducing the pathology of Alzheimer’s disease,including amyloid-β,tau protein,and neuroinflammation,and secreting neurotrophic factors and growth factors that are related to *** events can promote synaptic plasticity and neurogenesis to repair the microenvironment of the mammalian ***,neural stem cells are considered to represent a potential regenerative therapy with which to improve Alzheimer’s disease and other neurodegenerative *** this review,we discuss how neural stem cells regulate neuroplasticity and optimize their effects to enhance their potential for treating Alzheimer’s disease in the clinic.

关键词： Alzheimer’s disease amyloid-β cell therapy extracellular vesicle neural stem cell synaptic plasticity tau

Behaviors analysis of on-coming cluster based on knowledge under cluster security requirements

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Chinese Journal of Aeronautics 2024年第9期37卷 448-462页

作者： Huixia ZHANG yan liang Ying SHI Yuedong WANG Chaoxiong MA Ran WANG School of Automation Northwestern Polytechnical UniversityXi'an 710129China Key Laboratory of Information Fusion Technology Ministry of EducationXi'an 710129China

Analysis of cluster behaviors of the on-coming cluster is an essential measure for high value locations on the *** target tracking and clustering analysis,cluster behaviors analysis under cluster security requirements remains an open issue,which is a joint analysis of clus-tering,intent reasoning and activity *** address this issue,a framework for cluster behav-iors analysis is proposed by incorporating expert knowledge and domain knowledge,and a knowledge-assisted score function with is designed to improve the accuracy of intent reasoning net-work,overcoming the effects of possible knowledge *** framework consists of three mod-ules for cluster analysis,intent reasoning and activity region analysis for typical tasks,in which an intent reasoning network is constructed to obtain cluster intents by using a hybrid knowledge and data driven ***,considering the complexity of the battlefield environment,dif-ferent tasks and corresponding activity region optimization functions are designed for cluster activ-ity region analysis,which are vital elements of cluster behaviors *** demonstrate the effectiveness of the proposed cluster behaviors analysis framework.

关键词： Cluster analysis Intent reasoning,Activity region analysis Cluster behavior Battlefield environment

Microstructure,wear and friction behavior of CoCrAITaY-xCNTs composite coatings deposited by laser-induction hybrid cladding

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Rare Metals 2024年第4期43卷 1815-1827页

作者： Sheng-Feng Zhou Yu Long yan-liang Yi Cheng Deng Lian-Xi Hu Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou510632China Wuhan National Laboratory for Optoelectronics(WNLO) Huazhong University of Science and TechnologyWuhan430074China MOE Key Laboratory of New Processing Technology for Non-Ferrous Metals and Materials Guangxi Key Laboratory of Processing for Non-Ferrous Metals and Featured MaterialsGuangxi UniversityNanning530004China School of Mechatronics Engineering Guangdong Polytechnic Normal UniversityGuangzhou510635China School of Materials Science and Engineering Harbin Institute of TechnologyHarbin150001China

To improve the wear performance of CoCrAlYTa coating,part of the carbon nanotubes(CNTs)chemically reacted with Ta to form reinforcement phase(TaC),while the other CNTs were retained as lubrication ***,the CoCrAlYTa-xCNTs(x=0,1,2,and 4;wt%)composite coatings were prepared by laserinduction hybrid cladding(LIHC),and the microstructure and wear resistance of coatings were systematically *** show that the coatings are mainly composed of TaC,y-(Co,Cr)andβ-(Co,Cr)*** the CNTs content increases from 0 wt%to 4 wt%,the volume fraction of TaC increases from 13.11 vol%to 16.12 vol%.Meanwhile,the nano-hardness ofγ-(Co,Cr)andβ-(Co,Cr)Al are improved from 7.49 and 9.72 to 9.36 and 11.19 GPa,*** a result,the microhardness of coating increases from HV536.25 to HV 738.16,the wear rate decreases from32.4×10^(-3)to 6.1×10^(-3)mg·m^(-1),and the average friction coefficient decreases from 0.55 to *** good wear performance of the coating is attributed to the formation of TaC and the existence of remained CNTs lubricant film.

关键词： Carbon nanotube MCrAlY coating Friction and wear performance Laser-induction hybrid cladding

Self-assembly tungsten selenide hybrid ternary MOF derived magnetic alloys via multi-polarization to boost microwave absorption

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Nano Research 2024年第3期17卷 1625-1635页

作者： Tianbao Zhao Tingting Zheng Di lan yan Zhang Zhengshuo Sun Chao Wang Zirui Jia Guanglei Wu Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China School of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002China College of Chemistry and Chemical Engineering Qingdao UniversityQingdao 266071China

Confronted with severe electromagnetic wave pollution,the development of high-performance electromagnetic wave shielding or absorbing materials is an effective way to deal with ***,double transition metal alloys and transition metal dichalcogenides have attracted extensive attention in electromagnetic wave absorption,but few reports have studied the effects of these two materials on electromagnetic wave absorption at the same *** this work,cobalt-based alloy with magnetic loss mechanism was selected for composition *** ternary metal-organic framework was prepared by the one-step method,and then CoCu/C was prepared by high temperature ***,in the hydrothermal process,ultra-thin tungsten selenide nanosheets were coated on the surface of magnetic component,and the final polyhedral WSe_(2)/CoCu/C composites with multiple heterogeneous interfaces were *** synergistic effect of dielectric and magnetic components optimizes impedance matching and allows more electromagnetic waves to enter the ***,through the conduction loss of high conductivity graphitized carbon,interfacial polarization,and dipole polarization of heterogeneous interfaces between the components,the magnetic loss provided by CoCu alloy can work together to maximize the attenuation ability of electromagnetic ***,the minimum reflection loss(RLmin)value of the composite reaches-53.43 dB when the matched thickness is 2.1 mm,while the maximum effective absorption bandwidth(EABmax)reaches 6.0 GHz at a thin thickness of 1.8 *** work provides some support and reference for the design of novel electromagnetic wave absorbing materials via the dielectric/magnetic loss synergistic mechanism.

关键词： metal-organic framework dielectric/magnetic loss transition metal dichalcogenide electromagnetic wave absorption

Monothetic and conductive network and mechanical stress releasing layer on micron-silicon anode enabling high-energy solid-state battery

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Rare Metals 2024年第3期43卷 1017-1029页

作者： Xiang Han Min Xu lan-Hui Gu Chao-Fei lan Min-Feng Chen Jun-Jie Lu Bi-Fu Sheng Peng Wang Song-yan Chen Ji-Zhang Chen College of Materials Science and Engineering Co-Innovation Center of Efficient Processing and Utilization of Forestry ResourcesNanjing Forestry UniversityNanjing210037China Department of Physics Xiamen UniversityXiamen361005China Western Digital Corporation MilpitasCA95035USA

Silicon has ultrahigh capacity,dendrite-free alloy lithiation mechanism and low cost and has been regarded as a promising anode candidate for solid-state *** to the low infiltration of solid-state electrolyte(SSE),not the unstable solid-electrolyte interphase(SEI),but the huge stress during lithiation-and delithiation-induced particle fracture and conductivity lost tend to be the main *** this study,starting with micron-Si,a novel monothetic carbon conductive framework and a MgO coating layer are designed,which serve as electron pathway across the whole electrode and stress releasing layer,*** addition,the in situ reaction between Si and SSE helps to form a LiF-rich and mechanically stable SEI *** a result,the mechanical stability and charge transfer kinetics of the uniquely designed Si anode are significantly ***,high initial Coulombic efficiency,high capacity and durable cycling stability can be achieved by applying the Si@MgO@C anode in *** example,high specific capacity of 3224.6 mAh·g^(-1)and long cycling durability of 200 cycles are *** work provides a new concept for designing alloy-type anode that combines surface coating on particle and electrode structure design.

关键词： Lithium-ion battery(LIB) Solid-state electrolyte(SSE) Silicon anode Stress relief Coating

Effects of heat treatment on microstructures and properties of a heterostructured alloy with dissimilar components fabricated by WAAM

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Rare Metals 2024年第9期43卷 4441-4461页

作者： Ming-Cai Pan Jun-Qiang Xu Yong Peng Ning-Ning liang Si lan Qi Zhou Ke-Hong Wang School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China Key Laboratory of Controlled Arc Intelligent Additive Manufacturing Technology Nanjing 210094China

Heat treatment significantly influences homogeneous material microstructures and mechanical properties,which can be improved by an optimal heat treatment ***,heat treatment application to heterogeneous materials presents significant challenges due to compositional and microstructural ***,a laminated heterostructured alloy comprising alternating316L stainless steel(SS)and 18Ni300 maraging steel(MS)layers fabricated using wire and arc additive manufacturing was investigated.A solution treatment was applied at900℃for 0.5 ***,the solution-treated and asfabricated(AF)samples were aged at 500℃for 4 h;these samples were denoted SA and AT,*** AT phase compositions and orientations were similar to those of *** SA 316L SS layer resembled that of AF,but the SA 18Ni300 MS layers exhibited a reduced austenite phase fraction and refined grain size,attributable to solid-state *** the AT sample,aging induced the formation of nanoscale acicularωphase and ellipsoidal Ni_(3)Ti,Fe_(2)Mo,and X precipitates in the 18Ni300 MS ***,the SA precipitates contained acicular Fe Ni_(2)and ellipsoidalω,Ni_(3)Ti,and X precipitates,and their fractions were lower than those in AT ***18Ni300 MS layer microhardness in the heat-treated samples increased due to nanoprecipitation,but the 316L SS layer microhardness resembled that of *** AT and SA ultimate tensile strengths increased to(1360±50)and(1473±41)MPa,respectively,attributable to precipitation *** SA 316L SS layer exhibited a high stress-induced martensite fraction,enhancing the ductility of heated samples.

关键词： Laminated heterostructured alloy Heat treatment Wire and arc additive manufacturing Microstructure Mechanical property

Engineering a high-barrier d-f single-molecule magnet centered with hexagonal bipyramidal Dy(Ⅲ)unit

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Science China Chemistry 2024年第10期67卷 3291-3298页

作者： Wei Deng Chan-Ying Yao yan-Cong Chen Ying-Qian Zhou Shan-Nan Du Jun-liang Liu Ming-liang Tong Key Laboratory of Bioinorganic and Synthetic Chemistry of Ministry of Education School of ChemistryInstitute of Green Chemistry and Molecular EngineeringGuangdong Basic Research Center of Excellence for Functional Molecular EngineeringSun Yat-sen UniversityGuangzhou 510006China

In the pursuit of high-performance single-molecule magnets(SMMs),incorporating intramolecular magnetic coupling emerges as a pivotal *** these,d-f SMMs have garnered significant attention due to their remarkable versatility,which lies in their ability to tune coordination environments and facilely substitute metal ***,achieving performance-centric d-f SMMs through the synergistic interplay between highly anisotropic f ions and d-f magnetic interactions remains a formidable *** mononuclear hexagonal bipyramidal(D_(6h))Dy^(Ⅲ)SMMs have been successfully isolated,the exploration of d-f SMMs featuring D_(6h)-lanthanide metal centers remains uncharted *** this study,we employed planar bipodal ligands in conjunction with“staple-like”axial phenoxide ligands to synthesize the first hexagonal bipyramidal d-f ***,this compound exhibits alternating-current magnetic susceptibilities peaking up to 68 K with an energy barrier surpassing 1,200 K,thus establishing a new benchmark within the heterometallic d-f SMM landscape inclusive of complexes with diamagnetic d metals and paramagnetic f ***,the ferromagnetic interaction at the d-f sites engenders oscillating relaxation times contingent on the magnetic field—a characteristic distinct from mononuclear *** findings shed light on a deliberate design approach for d-f SMMs,emphasizing the cooperative utilization of high-barrier lanthanide modules alongside d ions through magnetic *** synergy significantly enhances and diversifies the magnetic dynamics of these intriguing molecular systems.

关键词： single-molecule magnets magnetic coupling crystal engineering hexagonal bipyramid energy barrier

Boron nitride nanofibers enhanced composite PEO-based solid-state polymer electrolytes for lithium metal batteries

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Chinese Chemical Letters 2024年第6期35卷 216-221页

作者： Qianqian Song Yunting Zhang Jianli liang Si Liu Jian Zhu Xingbin yan School of Materials Science and Engineering Sun Yat-Sen UniversityGuangzhou 510275China College of Physics and Materials Science Tianjin Normal UniversityTianjin 300387China Department of Chemistry&Center of Super-Diamond and Advanced Films(COSDAF) City University of Hong KongHong Kong 999077China Guangdong-Hong Kong-Macao Joint Laboratory for Intelligent Micro-Nano Optoelectronic Technology School of Physics and Optoelectronic EngineeringFoshan UniversityFoshan 528225China

Polyethylene oxide(PEO)-based solid-state polymer electrolytes(SPEs)are limited by their poor cyclic stability and inferior ionic conductivity for applicating in high-safety,long-cycling and high-energy-density lithium metal ***,porous boron nitride nanofibers(BNNFs)are filled into PEO-based SPE,which significantly suppresses Li dendrites growth and enhances the electrochemical performance of Li metal *** with high porosity have more active sites to connect with PEO,which can effectively reduce the crystallinity of the PEO matrix and enhance its ionic ***,owing to the hardness and good stability of BNNFs,BNNFs/PEO/Li TFSI electrolyte exhibits a wider electrochemical window,better mechanical property and higher thermal stability compared with PEO/Li TFSI ***,the Li symmetric cell composed of 1%BNNFs/PEO/Li TFSI performs good cyclic stability(>1800 h),and the Li||1%BNNFs/PEO/Li TFSI||LFP full battery shows obviously improved performances in charge-discharge polarization voltage,discharge specific capacity,rate performance and cyclic stability than the Li||PEO/Li TFSI||LFP battery.

关键词： Solid-state polymer electrolyte Boron nitride nanofibers Lithium metal battery Ionic conductivity Li dendrite