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Structural evolution and high-temperature sensing performance of polymer-derived SiAlBCN ceramics

Journal of Advanced Ceramics 2024年第4期13卷 478-485页

作者： Chao Ma Kun Liu Pengfei Shao Daoyang Han Kang Wang Mengmeng Yang Rui Zhao Hailong Wang Rui Zhang Gang Shao School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Zhongyuan Critical Metal Laboratory Zhengzhou UniversityZhengzhou 450001China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentZhengzhou UniversityZhengzhou 450002China

In situ temperature monitoring has become extremely imperative in high-temperature harsh environments and polymer-derived ceramics(PDCs)as sensing materials have attracted great ***,the stability and oxidation/corrosion resistance of PDCs cannot be simultaneously achieved at the moment,limiting their practical ***,polymer-derived SiAlBCN ceramics were synthesized via polymer conversion method under different pyrolysis *** microstructure evolution,high temperature sensing properties,and stability were investigated in *** results show that the amorphous SiAlBCN phase grows more orderly and the size of the free carbon phase enlarges with the increasing *** defect concentration displays a decreasing ***,the SiAlBCN ceramics as sensing materials exhibit a good temperature-resistance property from roo temperature to 1100℃.The fabricated SiAlBCN temperature sensor possesses excellent stability,repeatability,and ***,SiAlBCN ceramics exhibit distinguished oxidation/corrosion resistance after 100 h treatment at 1200℃in a water/oxygen environment,which is attributed to their low corrosive rate constant(0.57 mg/(cm^(2)·h))and oxidative rate constant(3.43 mg^(2)/(cm^(4)·h)).Therefore,polymer-derived SiAlBCN ceramics as sensing materials,which possess outstanding stability and oxidation/corrosion resistance,have great potential for in-situ monitoring of extreme environmental temperatures in the future.

关键词： polymer-derived SiAlBCN ceramics temperature sensor harsh environments oxidation and corrosion resistance

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Absorption-Reflection-Transmission Power Coefficient Guiding Gradient Distribution of Magnetic MXene in Layered Composites for Electromagnetic Wave Absorption

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Nano-Micro Letters 2025年第6期17卷 466-481页

作者： Yang Zhou Wen Zhang Dong Pan Zhaoyang Li Bing Zhou Ming Huang Liwei Mi Chuntai Liu Yuezhan Feng Changyu Shen State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentNational Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002People’s Republic of China Yaoshan Laboratory Pingdingshan UniversityPingdingshan 467000People’s Republic of China

The morphological distribution of absorbent in composites is equally important with absorbents for the overall electromagnetic properties,but it is often ***,a comprehensive consideration including electromagnetic component regulation,layered arrangement structure,and gradient concentration distribution was used to optimize impedance matching and enhance electromagnetic *** the microscale,the incorporation of magnetic Ni nanoparticles into MXene nanosheets(Ni@MXene)endows suitable intrinsic permittivity and *** the macroscale,the layered arrangement of Ni@MXene increases the effective interaction area with electromagnetic waves,inducing multiple reflection/scattering *** this basis,according to the analysis of absorption,reflection,and transmission(A-R-T)power coefficients of layered composites,the gradient concentration distribution was constructed to realize the impedance matching at low-concentration surface layer,electromagnetic loss at middle concentration interlayer and microwave reflection at high-concentration bottom ***,the layered gradient composite(LG5-10-15)achieves complete absorption coverage of X-band at thickness of 2.00-2.20 mm with RL_(min) of-68.67 dB at 9.85 GHz in 2.05 mm,which is 199.0%,12.6%,and 50.6%higher than non-layered,layered and layered descending gradient composites,***,this work confirms the importance of layered gradient structure in improving absorption performance and broadens the design of high-performance microwave absorption materials.

关键词： Magnetic MXene Layered and gradient structure Power coefficient Electromagnetic wave absorption

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Micromechanical modeling of longitudinal tensile behavior and failure mechanism of unidirectional carbon fiber/aluminum composites involving fiber strength dispersion

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Chinese Journal of Aeronautics 2024年第9期37卷 312-327页

作者： Qipeng LIU Wengang JIANG Yuehua GAO Zhenjun WANG Shanshan SHI Zhi SUN Jiangxi Key Laboratory of Forming and Joining Technology for Aerospace Components Nanchang Hangkong UniversityNanchang 330063China School of Locomotive and Rolling Stock Engineering Dalian Jiaotong UniversityDalian 116028China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

This paper examines the longitudinal tensile behavior and failure mechanism of a new unidirectional carbon fiber reinforced aluminum composite through experiments and simulations.A Weibull distribution model was established to describe the fiber strength dispersion based on single-fiber tensile tests for carbon fibers extracted from the *** constitutive models for the matrix and interface were established based on the uniaxial tensile and single-fiber push-out tests,***,a 3D micromechanical numerical model,innovatively considering the fiber strength dispersion by use of the weakest link and Weibull distribution theories,was estab-lished to simulate the progressive failure behavior of the composite under longitudinal *** to the dispersion of fiber strength,the weakest link of the fiber first fractures,and stress concentra-tion occurs in the surrounding fibers,interfaces,and *** maximum stress concentration fac-tor for neighboring fibers varies nonlinearly with the distance from the fractured *** isolated and clustered fractured fibers are present during the progressive failure process of the *** expansion of fractured fiber clusters intensifies stress concentration and material degradation which in turn enlarges the fractured fiber clusters,and their mutual action leads to the final collapse of the composite.

关键词： Fiber reinforced metals Finite element method 3D micromechanical model Fiber strength dispersion Longitudinal tension Progressive failure

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Research on performance optimization of virtual data space across WAN

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Frontiers of Computer Science 2024年第6期18卷 167-187页

作者： Jiantong HUO Zhisheng HUO Limin XIAO Zhenxue HE State Key Laboratory of Software Development Environment Beihang UniversityBeijing 100191China School of Computer Science and Engineering Beihang UniversityBeijing 100191China High Performance Computing Center Beihang UniversityBeijing 100191China Hebei Key Laboratory of Agricultural Big Data Hebei Agricultural UniversityBaoding 071001China

For the high-performance computing in a WAN environment,the geographical locations of national supercomputing centers are scattered and the network topology is complex,so it is difficult to form a unified view of *** aggregate the widely dispersed storage resources of national supercomputing centers in China,we have previously proposed a global virtual data space named GVDS in the project of“High Performance Computing Virtual Data Space”,a part of the National key Research and Development Program of *** GVDS enables large-scale applications of the high-performance computing to run efficiently across ***,the applications running on the GVDS are often data-intensive,requiring large amounts of data from multiple supercomputing centers across *** this regard,the GVDS suffers from performance bottlenecks in data migration and access across *** solve the above-mentioned problem,this paper proposes a performance optimization framework of GVDS including the multitask-oriented data migration method and the request access-aware IO proxy resource allocation *** a WAN environment,the framework proposed in this paper can make an efficient migration decision based on the amount of migrated data and the number of multiple data sources,guaranteeing lower average migration latency when multiple data migration tasks are running in *** addition,it can ensure that the thread resource of the IO proxy node is fairly allocated among different types of requests(the IO proxy is a module of GVDS),so as to improve the application’s performance across *** experimental results show that the framework can effectively reduce the average data access delay of GVDS while improving the performance of the application greatly.

关键词： storage aggregation across WANs large-scale applications GVDS data migration allocation of IO proxy resource

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Compressible thermoplastic polyurethane/silver nanorod foams for absorption dominant electromagnetic interference shielding

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Journal of Materials Science & Technology 2024年第30期197卷 9-16页

作者： Zhaoyang Li Yong Shen Yang Zhou Bing Zhou Chuntai Liu Yuezhan Feng State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentNational Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002China Shangqiu Normal University Shangqiu 476000China

Conductive polymer composites(CPCs)have attracted significant interest in the field of flexible electro-magnetic protection,but the challenge of balancing high electromagnetic interference shielding effec-tiveness(EMI SE)and low reflection losses still ***,thermoplastic polyurethane/silver nanorod(TPU/AgNR)composite foams have been successfully prepared using both the salt template and vacuum-assisted thermal compression *** varying the AgNRs content and employing a layer-by-layer bonding approach,a gradient structure with optimized impedance matching is ***“absorb-reflect-reabsorb”EM attenuation mechanismofthe asymmetricgradientEMI shieldingin theinternal structure is exploited,resulting in TPU/AgNR foam(TAF)with high EMI SE and significantly reduced EM ***,the three-layer foams exhibit an average shielding efficacy of 35.5 dB and a reflected power coefficient(R)of 0.085 in the X-band,thereby substantially mitigating secondary EM wave ***,these foams demonstrate exemplary compressive resilience,with the sample main-taining excellent EMI shielding stability even after undergoing 100 compression cycles at 50%***,a straightforward approach is employed to fabricate materials with high EMI SE and low reflectivity,offering the potential for use in EM shielding applications of next-generation flexible elec-tronic devices.

关键词： Thermoplastic polyurethane foam Asymmetric gradient structure EMI shielding EM wave absorption Mechanical properties

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Highly oriented MXene/polyvinyl alcohol films prepared by scalable layer-by-layer blade coating for efficient electromagnetic interference shielding and infrared stealth

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Nano Research 2024年第6期17卷 5651-5660页

作者： Jingyu Dong Zhaoyang Li Congqi Liu Bing Zhou Chuntai Liu uezhan Feng State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentNational Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002China Shangqiu Normal University Shangqiu 476000China

Controlling the orientation of two-dimensional MXene within layered films is essential to optimize or tune their mechanical properties and electromagnetic interference shielding(EMI)performance,but achieving the high orientation MXene layers on an industrial scale remains a challenging *** this paper,a scalable layer-by-layer blade coating(LbLBC)method was employed to fabricate highly oriented MXene/polyvinyl alcohol(PVA)*** the LbLBC process,MXene/PVA colloid suffered a strong shearing effect,which induced the ordered alignment of MXene nanosheets along the direction of the blade *** orientation of MXene can be effectively adjusted by changing the scraping gap of LbLBC,achieving a maximum Herman orientation factor f of *** a result,the mechanical properties and EMI performance of the as-prepared MXene/PVA films are in direct proportion to their orientation,with the optimal values of tensile strength of 145.5 MPa,fracture strain of 19.6%,toughness of 17.7 MJ·m^(−3),and EMI shielding effectiveness of 36.7 ***,the inherently low mid-infrared(mid-IR)emissivity of MXene,combined with the densely oriented structure affords the composite films with IR stealth,resulting in a substantial decrease from 150 to 66.1℃in the radiative temperature of a ***,these scalable MXene/PVA films exhibit remarkable potential for integration into the next generation of multifunctional protective camouflage materials.

关键词： MXene nanosheets densely oriented structure layer-by-layer blade coating electromagnetic interference shielding infrared stealth

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Multi-layer network embedding on scc-based network with motif

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Digital Communications and Networks 2024年第3期10卷 546-556页

作者： Lu Sun Xiaona Li Mingyue Zhang Liangtian Wan Yun Lin Xianpeng Wang Gang Xu Department of Communication Engineering Institute of Information Science TechnologyDalian Maritime UniversityDalian116026China Key Laboratory of Big Data Intelligent Computing Chongqing University of Posts and TelecommunicationsChongqing400065China Key Laboratory for Ubiquitous Network and Service Software of Liaoning Province DUT School of Software Technology&DUT-RU International School of Information Science and EngineeringDalian University of TechnologyDalian 116620China College of Information and Communication Engineering Harbin Engineering UniversityHarbin 150001China School of Information and Communication Engineering Hainan UniversityHaikou 570228China State Key Laboratory of Millimeter Waves School of Information Science and EngineeringSoutheast UniversityNanjing 210096China

Interconnection of all things challenges the traditional communication methods,and Semantic Communication and Computing(SCC)will become new *** is a challenging task to accurately detect,extract,and represent semantic information in the research of SCC-based *** previous research,researchers usually use convolution to extract the feature information of a graph and perform the corresponding task of node ***,the content of semantic information is quite *** graph convolutional neural networks provide an effective solution for node classification tasks,due to their limitations in representing multiple relational patterns and not recognizing and analyzing higher-order local structures,the extracted feature information is subject to varying degrees of ***,this paper extends from a single-layer topology network to a multi-layer heterogeneous topology *** Bidirectional Encoder Representations from Transformers(BERT)training word vector is introduced to extract the semantic features in the network,and the existing graph neural network is improved by combining the higher-order local feature module of the network model representation network.A multi-layer network embedding algorithm on SCC-based networks with motifs is proposed to complete the task of end-to-end node *** verify the effectiveness of the algorithm on a real multi-layer heterogeneous network.

关键词： Semantic communication and computing Multi-layer network Graph neural network Motif

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Three-dimensional reconstruction of industrial parts from a single image

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Visual Computing for Industry,Biomedicine,and Art 2024年第1期7卷 340-351页

作者： Zhenxing Xu Aizeng Wang Fei Hou Gang Zhao School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Key Laboratory of Aeronautics Smart Manufacturing Beihang UniversityBeijing 100191China State Key Laboratory of Computer Science Institute of SoftwareChinese Academy of SciencesBeijing 100190China

This study proposes an image-based three-dimensional(3D)vector reconstruction of industrial parts that can gener-ate non-uniform rational B-splines(NURBS)surfaces with high fidelity and *** contributions of this study include three parts:first,a dataset of two-dimensional images is constructed for typical industrial parts,including hex-agonal head bolts,cylindrical gears,shoulder rings,hexagonal nuts,and cylindrical roller bearings;second,a deep learning algorithm is developed for parameter extraction of 3D industrial parts,which can determine the final 3D parameters and pose information of the reconstructed model using two new nets,CAD-ClassNet and CAD-ReconNet;and finally,a 3D vector shape reconstruction of mechanical parts is presented to generate NURBS from the obtained shape *** final reconstructed models show that the proposed approach is highly accurate,efficient,and practical.

关键词： Three-dimensional reconstruction Non-uniform rational B-splines Industrial parts Deep learning

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Real-time prediction of mechanical behaviors of underwater shield tunnel structure using machine learning method based on structural health monitoring data

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Journal of Rock Mechanics and Geotechnical engineering 2023年第4期15卷 886-895页

作者： Xuyan Tan Weizhong Chen Tao Zou Jianping Yang Bowen Du State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China University of Chinese Academy of Sciences Beijing100049China State Key Laboratory of Software Development Environment Beihang UniversityBeijing100191China

Predicting the mechanical behaviors of structure and perceiving the anomalies in advance are essential to ensuring the safe operation of infrastructures in the long *** addition to the incomplete consideration of influencing factors,the prediction time scale of existing studies is ***,this study focuses on the development of a real-time prediction model by coupling the spatio-temporal correlation with external load through autoencoder network(ATENet)based on structural health monitoring(SHM)*** autoencoder mechanism is performed to acquire the high-level representation of raw monitoring data at different spatial positions,and the recurrent neural network is applied to understanding the temporal correlation from the time ***,the obtained temporal-spatial information is coupled with dynamic loads through a fully connected layer to predict structural performance in next 12 *** a case study,the proposed model is formulated on the SHM data collected from a representative underwater shield *** robustness study is carried out to verify the reliability and the prediction capability of the proposed ***,the ATENet model is compared with some typical models,and the results indicate that it has the best *** model is of great value to predict the realtime evolution trend of tunnel structure.

关键词： Shied tunnel Machine learning Monitoring Real-time prediction Data analysis

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Learning to represent code semantics

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Science China(Information Sciences) 2025年

作者： Fang LIU Ge LI Qianhui ZHAO Li ZHANG State Key Laboratory of Complex & Critical Software Environment School of Computer Science & Engineering Beihang University Key Laboratory of High Confidence Software Technologies (Peking University) Ministry of Education School of Computer Science Peking University

Code semantic learning serves as the basis of many program analysis tasks. Researchers have paid much effort to build robust and effective code representation models over the years. One line of work focuses on introducing the code structure into the representations. To further improve the robustness of the code representation, approaches based on compiler intermediate representations(IRs) are proposed. However, these IR-based models suffer from heavy computational costs and memory overhead. How to represent program semantics effectively and efficiently still remains a challenge. To this end, we propose EECS, an effective and efficient code semantic representation approach based on compiler IRs and a hybrid attention mechanism. For input representation, to address the unlimited vocabulary size issue in IR, we propose a variable identification strategy to allocate each register variable to a new ID that can represent their relative positions. Besides, we also extract the data flow information among the code blocks. Then we build a hierarchical multi-layer Transformer encoder to capture the data dependency information as well as the code semantics through a hybrid attention mechanism. To enable EECS to learn code semantics and functionality better, we optimize three objectives jointly during the training *** results on three code semantic understanding tasks show that EECS performs better than the state-of-the-art techniques, demonstrating the remarkable capability of EECS on program semantics understanding.

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