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Flower-like CuS/γ-Fe_(2)O_(3) van der waals heterostructures with highefficient electromagnetic wave absorption

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nano Research 2024年第4期17卷 3324-3333页

作者： na lu Jingshen Xu Mengwei Yuan Genban Sun Beijing key laboratory of Energy Conversion and Storage Materials Institution College of ChemistryBeijing Normal UniversityBeijing 100875China Center for Advanced Materials Research Beijing Normal UniversityZhuhai 519087China

the escalating electromagnetic(EM)pollution issues and the demand to elevate military stealth technology make it imperative to develop cost-effective and high-performance electromagnetic wave(EMw)absorbing *** this paper,the flower-like CuS/γ-Fe_(2)O_(3) van der waals(vdw)heterostructures have been synthesized via a facile two-step solvothermal *** flower-like CuS skeleton increases the attenuation path of EMw while reducing the material *** contents ofγ-Fe_(2)O_(3) nanoparticles anchor between the flower-like CuS nanosheets to constitute a heterogeneous structure,which enables dielectric and magnetic loss synergistically to optimize impedance matching and remarkably improve the EMw absorption *** minimum reflection loss(Rlmin)is-49.36 dB with a thickness of only 1.6 mm and the effective absorption bandwidth(EAB)reaches 4.64 GHz(13.36–18 GHz).By adjusting the thickness of the absorber,the EAB can cover 96%of the GHz ***,the superior absorption of-61.53 dB at middle frequency band can be obtained by adjusting the amount of Fe_(2)O_(3) *** this study,the adjustment of EM parameters and the optimization of impedance matching have been achieved by constructing a novel vdw heterogeneous structure,which provides fresh ideas and references for the design of high-performance EMw absorbing materials.

关键词： flower-like CuS γ-Fe_(2)O_(3) van der waals heterostructures impedance matching electromagnetic wave absorption

Autonomy Evaluation of Unmanned Systems Based on Task Models

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Machine Intelligence Research 2024年第5期21卷 815-830页

作者： Yi Zou Zehao ni Xun lei chi Zhang key laboratory of Complex Aviation Simulation System Beijing100076China State key laboratory of Multimodal Artificial Intelligence Systems(MAIS) Institute of AutomationChinese Academy of Sciences(CASIA)Beijing100190China Hong kong Institute of Science&Innovation Chinese Academy of Sciences(HKISI CAS)Hong Kong999077China

In this study,relevant work on autonomy evaluation(AE)in recent years was comprehensively reviewed and classified from the perspective of task models,and a closed-loop task models based theoretical framework for AE was *** main contributions of this study are as follows.1)A taxonomy for AE based on task models was introduced to classify current theories,methods and standards.2)the limitations of the current autonomous evaluation methods were addressed to provide a theoretical framework for quantitative evaluation based on task models,and evaluation metrics for each stage were proposed based on the AE theoretical framework.3)Qualitative analyses of the superiority of the proposed AE framework based on the closed-loop task models were *** study attempts to provide a reference for researchers and engineers in the autonomous unmanned systems field and inspire future development of AE.

关键词： Unmanned system(UMS) autonomy evaluation task models closed-loop task models kill chain

Energy-efficient joint UAV secure communication and 3D trajectory optimization assisted by reconfigurable intelligent surfaces in the presence of eavesdroppers

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Defence Technology（防务技术） 2024年第1期31卷 537-543页

作者： Huang Hailong Mohsen Eskandari Andrey V.Savkin wei ni the Department of Aeronautical and Aviation Engineering The Hong Kong Polytechnic UniversityHong KongChina School of Electrical Engineering and Telecommunications University of New South WalesSydney2052Australia Data61 CSIROAustralia

we consider a scenario where an unmanned aerial vehicle(UAV),a typical unmanned aerial system(UAS),transmits confidential data to a moving ground target in the presence of multiple *** friendly reconfigurable intelligent surfaces(RISs) help to secure the UAV-target communication and improve the energy efficiency of the *** formulate an optimization problem to minimize the energy consumption of the UAV,subject to the mobility constraint of the UAV and that the achievable secrecy rate at the target is over a given *** present an online planning method following the framework of model predictive control(MPC) to jointly optimize the motion of the UAV and the configurations of the *** effectiveness of the proposed method is validated via computer simulations.

关键词： Unmanned aerial systems(UASs) Unmanned aerial vehicle(UAV) Communication security Eaves-dropping Reconfigurable intelligent surfaces(RIS) Autonomous navigation and placement Path planning Model predictive control

Scattering-based hybrid network for facial attribute classification

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Frontiers of Computer Science 2024年第3期18卷 105-116页

作者： na lIU Fan ZHANG liang chANG Fuqing DUAN School of Artificial Intelligence Beijing Normal UniversityBeijing 100875China

Face attribute classification(FAC)is a high-profile problem in biometric verification and face *** recent research has been devoted to extracting more delicate image attribute features and exploiting the inter-attribute correlations,significant challenges still *** scattering transform(wST)is a promising non-learned feature *** has been shown to yield more discriminative representations and outperforms the learned representations in certain *** to the image classification task,wST can enhance subtle image texture information and create local deformation *** paper designs a scattering-based hybrid block,to incorporate frequency-domain(wST)and image-domain features in a channel attention manner(Squeezeand-Excitation,SE),termed wS-SE *** with CNN,wS-SE achieves a more efficient FAC performance and compensates for the model sensitivity of the small-scale affine *** addition,to further exploit the relationships among the attribute labels,we propose a learning strategy from a causal *** cause attributes defined using the causalityrelated information can be utilized to infer the effect attributes with a high confidence *** analysis experiments demonstrate the effectiveness of our model,and our hybrid model obtains state-of-the-art results in two public datasets.

关键词： wavelet scattering transform causality-related learning facial attribute classification

分立与整体:辽宋夏金时期中国历史整体性的发展轨迹

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史学集刊 2024年第5期 108-118页

作者：程尼娜吉林大学文学院中国史系吉林长春130012

辽宋夏金王朝是原唐朝统辖的民族在原唐疆域内建立的政权,各王朝统辖的各族人口中以汉人占多数。辽夏金王朝从国情出发,程度不同地继承中原王朝典章制度的同时,兼容了统治民族的传统制度和文化特点,体现了中国历史整体性的内在机制与发... 详细信息

辽宋夏金王朝是原唐朝统辖的民族在原唐疆域内建立的政权,各王朝统辖的各族人口中以汉人占多数。辽夏金王朝从国情出发,程度不同地继承中原王朝典章制度的同时,兼容了统治民族的传统制度和文化特点,体现了中国历史整体性的内在机制与发展轨迹。南北民族大迁徙使民族杂居状况更为普遍,客观上加速了民族融合,分布于内地与边疆、北族王朝与两宋王朝的同一民族内部割不断的亲缘关系,强化了古代中国社会底层的整体关系。各王朝统治者皆自称“正统”,将重建大一统王朝作为最高目标。儒家文化成为各王朝的主体文化,北族王朝积极吸纳汉文化精华发展本族文化,在客观上促进了不同民族在以儒学为主的整体文化层面上,实现了由浅入深的文化认同。

关键词：辽宋夏金整体性内聚力正统观文化认同

Recent Research Progress of Paper-Based Supercapacitors Based on Cellulose

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Energy & Environmental Materials 2024年第3期7卷 345-373页

作者： chuanyin Xiong Tianxu wang Jing Han zhao Zhang Yonghao ni College of Bioresources chemical&Materials Engineering Shaanxi University of Science and TechnologyXi'an 710021China School of Materials Science and Engineering Tianjin Polytechnic UniversityTianjin 300387China Department of chemical and Biomedical Engineering The University of MaineOronoMaine 04469USA University of New Brunswick Limerick Pulp&Paper CtrFredericton New Brunswick E3B 5A3Canada

In recent years,paper-based functional materials have received extensive attention in the field of energy storage due to their advantages of rich and adjustable porous network structure and good *** an important energy storage device,paper-based supercapacitors have important application prospects in many fields and have also received extensive attention from researchers in recent *** present,researchers have modified and regulated paper-based materials by different means such as structural design and material composition to enhance their electrochemical storage *** development of paper-based supercapacitors provides an important direction for the development of green and sustainable ***,it is of great significance to summarize the relevant work of paper-based supercapacitors for their rapid development and *** this review,the recent research progress of paper-based supercapacitors based on cellulose was summarized in terms of various cellulose-based composites,preparation skills,and electrochemical ***,some opinions on the problems in the development of this field and the future development trend were *** is hoped that this review can provide valuable references and ideas for the rapid development of paper-based energy storage devices.

关键词： cellulose electrochemical performance flexibility paper-based supercapacitor porous

Fixed-Time Sliding Mode Control with Varying Exponent Coefficient for Modular Reconfigurable Flight Arrays

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 514-528页

作者： Jianquan Yang chunxi Yang Xiufeng Zhang Jing na Faculty of Mechanical and Electrical Engineering Kunming University of Science and TechnologyKunming 650500 Yunnan International Joint laboratory of Intelligent Control and Aoolication of Advanced Equipment Kunming 650500China IEEE

the modular system can change its physical structure by self-assembly and self-disassembly between modules to dynamically adapt to task and environmental requirements. Recognizing the adaptive capability of modular systems, we introduce a modular reconfigurable flight array(MRFA) to pursue a multifunction aircraft fitting for diverse tasks and requirements,and investigate the attitude control and the control allocation problem by using the modular reconfigurable flight array as a platform. First, considering the variable and irregular topological configuration of the modular array, a center-of-mass-independent flight array dynamics model is proposed to allow control allocation under over-actuated situations. Secondly, in order to meet the stable, fast and accurate attitude tracking performance of the MRFA, a fixed-time convergent sliding mode controller with state-dependent variable exponent coefficients is proposed to ensure fast convergence rate both away from and near the system equilibrium point without encountering the singularity. It is shown that the controller also has fixed-time convergent characteristics even in the presence of external disturbances. Finally,simulation results are provided to demonstrate the effectiveness of the proposed modeling and control strategies.

关键词： Control allocation dynamic model fixed-time stabilization modular reconfigurable flight array(MRFA) sliding mode

Transjugular intrahepatic portosystemic shunt:A promising therapy for recompensation in cirrhotic patients

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world Journal of Gastroenterology 2024年第16期30卷 2285-2286页

作者： Ya-ni Jin wei Zhang Department of Gastroenterology Nanjing Drum Tower HospitalAffiliated Hospital of Medical SchoolNanjing UniversityNanjing 210000Jiangsu ProvinceChina

this is a retrospective study focused on recompensation after transjugular intrahepatic portosystemic shunt(TIPS)*** authors confirmed TIPS could be a treatment for recompensation of patients with cirrhosis according to Baveno *** paper identified age and post-TIPS portal pressure gradient as independent predictors of recompensation in patients with decompensated cirrhosis after *** results need to be validated in a larger prospective cohort.

关键词： Cirrhosis recompensation Transjugular intrahepatic portosystemic shunt Portal pressure gradient Predictor factor Baveno VII

High-current pulsed electron beam modification on microstructure and performance of Cu/Cuw diffusion bonding joints

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Rare Metals 2024年第6期43卷 2819-2831页

作者： na-na Tian Cong-lin Zhang Peng lyu Jin-Tong Guan Jie Cai Qing-Feng Guan Shun Guo School of Materials Science and Engineering Jiangsu UniversityZhenjiang 212013China School of Material Science and Engineering Yancheng Institute of TechnologyYancheng 221051China Engineering Institute of Advanced Manufacturing and Modern Equipment Technology Jiangsu UniversityZhenjiang 212013China

this study investigates the influence of high-current pulsed electron beam(HCPEB)modification on the microstructure and shear strength of Cu/Cuw *** solid-state diffusion bonding of modified-Cu(MCu)and modified-Cuw(M-Cuw)was achieved by HCPEB modification pretreatment at a temperature of 800-900℃and a pressure of 5 MPa for 10-50 *** demonstrate that HCPEB modification facilitates the dissolution of w and Cu,resulting in the formation of a Cu_(0.4)w_(0.6)solid solution and thus enhancing the uniform distribution of ***,HCPEB-induced defects play a beneficial role in promoting the diffusion process by providing fast diffusion paths for *** optimal joints with the maximum shear strength of 213.7 MPa were obtained through bonding M-Cu and M-Cuw at 900℃and 5 MPa for 30 min,which attributes to the combined effects of fine-grained strengthening and solid solution ***,the application of HCPEB modification showcases its effectiveness in promoting element diffusion and enhancing the mechanical performance of the joints.

关键词： HCPEB Element diffusion Shear strength Crystal defects Surface modification