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Space/air Covert Communications:Potentials,Scenarios,and Key Technologies

China Communications 2024年第3期21卷 1-18页

作者： Mao Haobin Liu Yanming zhu Lipeng Mao Tianqi Xiao Zhenyu Zhang Rui Han zhu Xia Xianggen School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Department of Electrical and Computer Engineering National University of SingaporeSingapore 117583Singapore School of Science and Engineering Shenzhen Research Institute of Big Datathe Chinese University of Hong KongShenzhenGuangdong 518172China Department of Electrical and Computer Engineering University of HoustonHoustonTX 77004USA Department of Computer Science and Engineering Kyung Hee UniversitySeoulSouth Korea446-701 Department of Electrical and Computer Engineering University of DelawareNewarkDE 19716USA

Space/air communications have been envisioned as an essential part of the next-generation mobile communication networks for providing highquality global connectivity. However, the inherent broadcasting nature of wireless propagation environment and the broad coverage pose severe threats to the protection of private data. Emerging covert communications provides a promising solution to achieve robust communication security. aiming at facilitating the practical implementation of covert communications in space/air networks, we present a tutorial overview of its potentials, scenarios, and key technologies. Specifically, first, the commonly used covertness constraint model, covert performance metrics, and potential application scenarios are briefly introduced. Then, several efficient methods that introduce uncertainty into the covert system are thoroughly summarized, followed by several critical enabling technologies, including joint resource allocation and deployment/trajectory design, multi-antenna and beamforming techniques, reconfigurable intelligent surface(RIS), and artificial intelligence algorithms. Finally, we highlight some open issues for future investigation.

关键词： artificial intelligence(ai) sixth generation(6G) space-air-ground integrated networks(SAGINs) space/air covert communications

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高速激光熔覆马氏体不锈钢涂层与电镀层性能对比与研究

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中国机械工程 2024年第8期35卷 1480-1488页

作者：王井艾超员霄朱迅郭飞燕山大学机械工程学院秦皇岛066004 江苏徐工工程机械研究院有限公司高端工程机械智能制造国家重点实验室徐州221004

为对比研究不同液压缸服役工况下高速激光熔覆涂层替代电镀硬铬层的可行性,分别制备了马氏体不锈钢熔覆层XG-1、XG-2和电镀硬铬涂层,开展了三种涂层组织、硬度、腐蚀性能及模拟不同工况(划伤磨损、干砂摩擦磨损、滑动摩擦磨损)下磨损性... 详细信息

为对比研究不同液压缸服役工况下高速激光熔覆涂层替代电镀硬铬层的可行性,分别制备了马氏体不锈钢熔覆层XG-1、XG-2和电镀硬铬涂层,开展了三种涂层组织、硬度、腐蚀性能及模拟不同工况(划伤磨损、干砂摩擦磨损、滑动摩擦磨损)下磨损性能测试,探讨了涂层失效行为及其应用工况。结果表明:XG-1、XG-2涂层微观组织致密且均匀,平均显微硬度为720.5 HV、653 HV;电镀硬铬涂层分布孔隙和裂纹等缺陷,自腐蚀电流密度为10.45μA/cm^(2),耐腐蚀性能最差;三种磨损形式下电镀硬铬涂层均发生了开裂及剥落,高速激光熔覆涂层表现出更优异的耐磨性能,适用于活塞杆易拉伤、外界富集硬质颗粒污染物、大侧向载荷等液压缸服役工况。

关键词：高速激光熔覆电镀硬铬磨损行为液压缸活塞杆马氏体不锈钢涂层

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Comprehensive Evaluation of Application Value of wild Flower Resources in Flower Border in Hefei City

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Journal of Landscape Research 2024年第3期16卷 48-50,58页

作者： zhu Rong ZHAO Zhiyan XU Huaxue MEng Yi GUAN Tianjing YIN Jia’ai Department of Architecture and Landscape Design Anhui Xinhua UniversityHefeiAnhui 230088China

In order to further understand and better develop and utilize wild flower resources in Hefei City,a comprehensive evaluation model of landscape value of wild flowers in the application of flower border was constructed by field investigation and analytic hierarchy process(AHP).The application value of wild flowers in Hefei was evaluated by selecting evaluation indicators from three aspects of ornamental value,adaptability and resource potential.

关键词： Analytic hierarchy process(AHP) wild flower resources Application value Comprehensive evaluation

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The FAST all sky HI survey(FASHI):The first release of catalog

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Science China(Physics,Mechanics & Astronomy) 2024年第1期67卷 112-133页

作者： Chuan-Peng Zhang Ming zhu Peng Jiang Cheng Cheng Jing w.ng Jie w.ng Jin-Long Xu Xiao-Lan Liu Nai-Ping Yu Lei Qian Haiyang Yu Mei ai Yingjie Jing Chen Xu Ziming Liu Xin Guan Chun Sun Qingliang Yang Menglin Huang Qiaoli Hao FAST Collaboration Guizhou Radio Astronomical Observatory Guizhou UniversityGuiyang 550000China National Astronomical Observatories Chinese Academy of Sciences(CAS)Beijing 100101China Chinese Academy of Sciences South America Center for Astronomy National Astronomical ObservatoriesCASBeijing 100101China Kavli Institute for Astronomy and Astrophysics Peking UniversityBeijing 100871China

The FAST All Sky HI survey(FASHI)was designed to cover the entire sky observable by the Five-hundred-meter Aperture Spherical radio Telescope(FAST),spanning approximately 22000 square degrees of declination between-14°and+66°,and in the frequency range of 1050-1450 MHz,with the expectation of eventually detecting more than 100000 HI *** August 2020 and June 2023,FASHI had covered more than 7600 square degrees,which is approximately 35%of the total sky observable by *** has a median detection sensitivity of around 0.76 m Jy beam-1and a spectral line velocity resolution of~6.4 km s-1at a frequency of~1.4 *** of now,a total of 41741 extragalactic HI sources have been detected in the frequency range 1305.5-1419.5 MHz,corresponding to a redshift limit of z■*** cross-matching FASHI sources with the Siena Galaxy Atlas(SGA)and the Sloan Digital Sky Survey(SDSS)catalogs,we found that 16972(40.7%)sources have spectroscopic redshifts and 10975(26.3%)sources have only photometric *** of the remaining 13794(33.0%)HI sources are located in the direction of the Galactic plane,making their optical counterparts difficult to identify due to high extinction or high contamination of Galactic stellar *** on current survey results,the FASHI survey is an unprecedented blind extragalactic H I *** has higher spectral and spatial resolution and broader coverage than the Arecibo Legacy Fast ALFA Survey(ALFALFA).when completed,FASHI will provide the largest extragalactic HI catalog and an objective view of HI content and large-scale structure in the local universe.

关键词： surveys redshifts galaxies telescope radio lines HI line

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基于强化学习的空间机器人柔性捕获控制研究

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华中科技大学学报（自然科学版） 2024年第5期52卷 150-157页

作者：艾海平鄂凯欣朱安陈力江西理工大学能源与机械工程学院江西南昌330013 福州大学机械工程及自动化学院福建福州350108

针对空间机器人双臂捕获卫星过程中的关节易受冲击力矩而破坏的问题,提出一种基于强化学习的柔性控制方法.首先,针对捕获前双臂空间机器人及卫星系统,分别利用拉格朗日方法及牛顿-欧拉法推导得其动力学模型;然后结合冲量定理、位置约束... 详细信息

针对空间机器人双臂捕获卫星过程中的关节易受冲击力矩而破坏的问题,提出一种基于强化学习的柔性控制方法.首先,针对捕获前双臂空间机器人及卫星系统,分别利用拉格朗日方法及牛顿-欧拉法推导得其动力学模型;然后结合冲量定理、位置约束关系及牛顿第三定律,建立捕获后空间机器人与卫星形成混合体系统的动力学模型.针对失稳的混合体系统,提出一种缓冲柔顺强化学习控制方案,该方案通过系统与环境的动态交互来实时优化控制策略以实现镇定过程的最优控制.仿真结果表明:所提控制方案最大可减少54.2%的冲击力矩,并在镇定阶段确保关节冲击力矩限制在安全范围内,从而保护关节免受冲击力矩的破坏.

关键词：空间机器人柔性机构双臂捕获卫星操作闭链系统缓冲柔顺控制强化学习

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Glucagon-like peptide-1 receptor agonists rescued diabetic vascular endothelial damage through suppression of aberrant STIng signaling

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Acta Pharmaceutica Sinica B 2024年第6期14卷 2613-2630页

作者： Xuemin He Siying wen Xixiang Tang Zheyao wen Rui Zhang Shasha Li Rong Gao Jin w.ng Yanhua zhu Dong Fang Ting Li Ruiping Peng Zhaotian Zhang Shiyi wen Li Zhou Heying ai Yan Lu Shaochong Zhang Guojun Shi Yanming Chen Department of Endocrinology and Metabolic Diseases the Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510630China Guangdong Provincial Key Laboratory of Diabetology&Guangzhou Municipal Key Laboratory of Mechanistic and Translational Obesity Research the Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510630China VIP Medical Service Center the Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510630China Department of Clinical Immunology the Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510630China Department of Ophthalmology the Third Affiliated Hospital of Sun Yat-sen UniversityGuangzhou 510630China State Key Laboratory of Ophthalmology Zhongshan Ophthalmic CenterSun Yat-sen UniversityGuangzhou 510060China Department of Fundus Shenzhen Eye Hospital of Jinan UniversityShenzhen 518048China

Glucagon-like peptide-1 receptor agonists(GLP-1 RAs)protect against diabetic cardiovascular diseases and ***,their activity in diabetic retinopathy(DR)remains *** retrospective cohort study involving 1626 T2DM patients revealed superior efficacy of GLP-1 RAs in controlling DR compared to other glucose-lowering medications,suggesting their advantage in DR *** single-cell RNA-sequencing analysis and immunostaining,we observed a high expression of GLP-1R in retinal endothelial cells,which was down-regulated under diabetic *** of GLP-1 RAs significantly restored the receptor expression,resulting in an improvement in retinal degeneration,vascular tortuosity,avascular vessels,and vascular integrity in diabetic *** and GSEA analyses further implicated enhanced mitochondrial gene translation and mitochondrial functions by GLP-1 ***,the treatment attenuated STIng signaling activation in retinal endothelial cells,which is typically activated by leaked mitochondrial *** of STIng mRNA was positively correlated to the levels of angiogenic and inflammatory factors in the endothelial cells of human fibrovascular *** investigation revealed that the cAMP-responsive element binding protein played a role in the GLP-1R signaling pathway on suppression of STIng *** study demonstrates a novel role of GLP-1 RAs in the protection of diabetic retinal vasculature by inhibiting STIng-elicited inflammatory signals.

关键词： GLP-1 RAs STIng signaling Retinal endothelial cells Mitochondrial leakage Retinal vascular dysfunction Diabetic retinopathy CREB Inflammation

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The electroweak monopole–antimonopole pair in the standard model

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Communications in Theoretical Physics 2024年第3期76卷 113-119页

作者： Dan zhu Khai-Ming w.ng Guo-Quan w.ng School of Physics Universiti Sains Malaysia11800 USMPenangMalaysia

we present the first numerical solution that corresponds to a pair of Cho–Maison monopoles and antimonopoles(MAPs) in the SU(2) × U(1) weinberg–Salam(wS) *** monopoles are finitely separated,while each pole carries a magnetic charge ±4π/*** positive pole is situated in the upper hemisphere,whereas the negative pole is in the lower *** Cho–Maison MAP is investigated for a range of weinberg angles,0.4675≤ tan θ_(w)≤10,and Higgs self-coupling,0 ≤ β ≤ *** magnetic dipole moment(μm) and pole separation(d_(z)) of the numerical solutions are calculated and *** total energy of the system,however,is infinite due to point singularities at the locations of monopoles.

关键词： magnetic monopole Cho-Maison monopole weinberg-Salam model

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High-resolution tsunami hazard assessment for the Guangdong-Hong Kong-Macao Greater Bay Area based on a non-hydrostatic tsunami model

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Science China Earth Sciences 2024年第7期67卷 2326-2351页

作者： Yifan zhu Chao AN Houyun YU wei ZHAng Xiaofei CHEN Key Laboratory of Hydrodynamics(Ministry of Education) School of Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Department of Earth and Space Sciences Southern University of Science and Technology Shenzhen 518055China

The Guangdong-Hong Kong-Macao Greater Bay Area(GBA)is threatened by potential tsunami hazards from the Littoral Fault Zone(LFZ)and the Manila subduction zone(MSZ),and may suffer huge damage because of its dense population,concentrated infrastructure,and low-lying *** tsunami studies for the GBA made simple assumptions on the mechanisms of LFZ earthquakes,and used coarse bathymetry data in tsunami simulation,which limited the prediction of detailed tsunami hazard *** this paper,we develop a parallel dispersive tsunami model PCOMCOT to efficiently simulate dispersive,nonlinear,and breaking tsunami *** also construct large-scale and high-resolution bathymetry models for the GBA by correcting and integrating various data *** rupture simulation is performed for the LFZ to obtain a more reliable earthquake source *** propose several representative earthquake scenarios for the LFZ and MSZ,and use PCOMCOT to calculate the resulting tsunami waves,currents,and inundation in the *** results indicate that if an M_(w)7.5 oblique-slip earthquake occurs in the LFZ off the Pearl River Estuary(PRE),the subsequent tsunami will primarily impact Hong Kong,causing maximum positive and negative waves of around 1 m and -2 m,respectively,along with slightly destructive currents(≥1.5 m/s).An M_(w)9.0 MSZ megathrust earthquake can lead to widespread inundation with>1 m depth on the outlying islands of Macao and in the urban areas of Hong Kong around the Victoria ***,it will also cause catastrophic tsunami currents along the narrow waterways in Hong Kong and Macao,and the spatial distribution of strong currents(≥3 m/s)shows a considerable discrepancy from the areas of serious ***,more attention should be paid to the potential impacts of tsunami currents on the GBA.

关键词： Tsunami hazards Inundation Tsunami currents Non-hydrostatic model Guangdong-Hong Kong-Macao Greater Bay Area

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Structural and magnetic properties of micropolycrystalline cobalt thin films fabricated by direct current magnetron sputtering

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International Journal of Minerals,Metallurgy and Materials 2024年第2期31卷 384-394页

作者： Kerui Song Zhou Li Mei Fang zhu Xiao Qian Lei School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Hunan Key Laboratory of Super-Microstructure and Ultrafast Process School of Physics and electronicsCentral South UniversityChangsha 410083China Key Laboratory of Non-Ferrous Metal Materials Science and Engineering Ministry of EducationChangsha 410083China

Pure cobalt(Co)thin films were fabricated by direct current magnetron sputtering,and the effects of sputtering power and pres-sure on the microstructure and electromagnetic properties of the films were *** the sputtering power increases from 15 to 60 w,the Co thin films transition from an amorphous to a polycrystalline state,accompanied by an increase in the intercrystal pore ***,the resistivity decreases from 276 to 99μΩ·cm,coercivity increases from 162 to 293 Oe,and in-plane magnetic aniso-tropy *** the sputtering pressure decreases from 1.6 to 0.2 Pa,grain size significantly increases,resistivity significantly de-creases,and the coercivity significantly increases(from 67 to 280 Oe),which can be attributed to the increase in defect ***-pondingly,a quantitative model for the coercivity of Co thin films was *** polycrystalline films sputtered under pressures of 0.2 and 0.4 Pa exhibit significant in-plane magnetic anisotropy,which is primarily attributable to increased microstress.

关键词： cobalt thin film magnetron sputtering microstructure electromagnetic properties

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Ultrahigh performance passive radiative cooling by hybrid polar dielectric metasurface thermal emitters

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Opto-Electronic Advances 2024年第4期7卷 17-25页

作者： Yinan Zhang Yinggang Chen Tong w.ng Qian zhu Min Gu Institute of Photonic Chips University of Shanghai for Science and TechnologyShanghai 200093China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China

Real-world passive radiative cooling requires highly emissive,selective,and omnidirectional thermal emitters to maintain the radiative cooler at a certain temperature below the ambient temperature while maximizing the net cooling *** various selective thermal emitters have been demonstrated,it is still challenging to achieve these conditions sim-ultaneously because of the extreme difficulty in controlling thermal emission of photonic structures in *** we demonstrated hybrid polar dielectric metasurface thermal emitters with machine learning inverse design,en-abling a high emissivity of~0.92 within the atmospheric transparency window 8-13μm,a large spectral selectivity of~1.8 and a wide emission angle up to 80 degrees,*** selective and omnidirectional thermal emitter has led to a new record of temperature reduction as large as~15.4°C under strong solar irradiation of~800 w/m2,signific-antly surpassing the state-of-the-art *** designed structures also show great potential in tackling the urban heat island effect,with modelling results suggesting a large energy saving and deployment area *** research will make significant impact on passive radiative cooling,thermal energy photonics and tackling global climate change.

关键词： radiative cooling dielectric metasurfaces machine learning thermal emitters

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