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self-Powered Absorptive Reconfigurable Intelligent surfaces for securing satellite-Terrestrial Integrated Networks

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China Communications 2024年第9期21卷 276-291页

作者： Lin Zhi Niu Hehao He Yuanzhi An kang Zhong Xudong Chu Zheng Xiao pei College of Electronic engineering National University of Defense TechnologyHefei 230037China sixty-Third Research Institute National University of Defense TechnologyNanjing 210007China Institute of systems.engineering Academy of Military ScienceBeijing 100141China Department of Electrical and Electronic engineering University of Nottingham Ningbo ChinaNingbo 315100China Institute for Communication systems University of SurreyGuildford GU27XHU.K.

satellite communications have attracted significant interests due to its advantages of large footprint and massive ***,the commonly used onboard beamforming is hard to achieve reliable security because of the highly correlated legitimate and wiretap downlink *** exploit the benefits of satellite-terrestrial integrated network(sTIN)and a novel absorptive reconfigurable intelligent surface(RIs)for improving the security of satellite downlink communications(sDC)in the presence of eavesdroppers(Eves).This paper aims to maximize the achievable secrecy rate of the earth station(Es)while satisfying the signal reception constraints,harvested power threshold at the RIs,and total transmit power *** solve this nonconvex problem,we propose a penalty-function based dual decomposition scheme,which firstly transforms the original problem into a two-layer optimization ***,the outer layer and inner problems are solved by utilizing the successive convex approximation,Lagrange-dual and Rayleigh quotient methods to obtain the beamforming weight vectors and the reflective coefficient ***,simulation results verify the effectiveness of the proposed scheme for enhancing the sDC security.

关键词： absorptive RIs beamforming design secure communications sTIN

spatially selective p-type doping for constructing lateral Ws_(2) p-n homojunction via low-energy nitrogen ion implantation

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Light(science & Applications) 2024年第6期13卷 1159-1169页

作者： Yufan kang Yongfeng pei Dong He Hang Xu Mingjun Ma Jialu Yan Changzhong Jiang Wenqing Li Xiangheng Xiao school of Physics and Technology Key Lab of Artificial Micro-and Nano-Structures of Ministry of EducationWuhan UniversityWuhanChina

The construction of lateral p-n junctions is very important and challenging in two-dimensional(2D)semiconductor manufacturing *** researches have demonstrated that vertical p-n junction can be prepared simply by vertical stacking of 2D ***,interface pollution and large area scalability are challenges that are difficult to overcome with vertical stacking *** 2D lateral p-n homojunction is an effective strategy to address these *** selective p-type doping of 2D semiconductors is expected to construct lateral p-n *** this work,we have developed a low-energy ion implantation system that reduces the implanted energy to 300 ***-energy implantation can form a shallow implantation depth,which is more suitable for modulating the electrical and optical properties of 2D ***,we utilize low-energy ion implantation to directly dope nitrogen ions into few-layer Ws_(2) and successfully realize a precise regulation for Ws_(2) with its conductivity type transforming from n-type to bipolar or even p-type ***,the universality of this method is demonstrated by extending it to other 2D semiconductors,including Wse_(2),sns_(2) and Mos_(2).Based on this method,a lateral Ws_(2) p-n homojunction is fabricated,which exhibits significant rectification characteristics.A photodetector based on p-n junction with photovoltaic effect is also prepared,and the open circuit voltage can reach to 0.39 *** work provides an effective way for controllable doping of 2D semiconductors.

关键词： implantation doping spatial

Emerging strategies and developments in oxygen reduction reaction using high-performance platinum-based electrocatalysts

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Nano Research 2024年第5期17卷 3516-3532页

作者： Asad Ali Aatto Laaksonen Guo Huang shahid Hussain shuiping Luo Wen Chen pei kang s.en Jinliang Zhu Xiaoyan Ji energy engineering Division of Energy ScienceLuleåUniversity of Technology97187 LuleåSweden Department of Materials and environmental Chemistry Arrhenius LaboratoryStockholm UniversitySE-10691 StockholmSweden Center of Advanced Research in Bionanoconjugates and Biopolymers “Petru Poni”Institute of Macromolecular ChemistryIasi 700469Romania state Key Laboratory of Materials-Oriented and Chemical engineering Nanjing Tech UniversityNanjing 211816China College of Materials science and engineering Shenzhen UniversityShenzhen 518060China school of Resources Environment and MaterialsState Key Laboratory of Processing for Non-ferrous Metal and Featured MaterialsGuangxi UniversityNanning 530004China

The global practical implementation of proton exchange membrane fuel cells(PEMFCs)heavily relies on the advancement of highly effective platinum(Pt)-based electrocatalysts for the oxygen reduction reaction(ORR).To achieve high ORR performance,electrocatalysts with highly accessible reactive surfaces are needed to promote the uncovering of active positions for easy mass *** this critical review,we introduce different approaches for the emerging development of effective ORR electrocatalysts,which offer high activity and *** strategies,including morphological engineering,geometric configuration modification via supporting materials,alloys regulation,core-shell,and confinement engineering of single atom electrocatalysts(sAEs),are discussed in line with the goals and requirements of ORR performance *** review the ongoing development of Pt electrocatalysts based on the syntheses,nanoarchitecture,electrochemical performances,and *** eventually explore the obstacles and research directions on further developing more effective electrocatalysts.

关键词： oxygen reduction reaction(ORR) Pt-based electrocatalysts proton exchange membrane fuel cells(PEMFCs) morphology and alloys strategies single atom electrocatalysts(sAEs)

sulfur doped iron-nitrogen-hard carbon nanosheets as efficient and robust noble metal-free catalysts for oxygen reduction reaction in PEMFC

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Journal of energy Chemistry 2024年第2期89卷 422-433,I0010页

作者： Bin Liu Jiawang Li Bowen Yan Qi Wei Xingyu Wen Huarui Xie Huan He pei kang s.en Zhi Qun Tian Collaborative Innovation Center of sustainable energy Materials School of Physical Science and TechnologyGuangxi UniversityGuangxi Key Laboratory of Electrochemical Energy MaterialsState Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite StructuresNanning 530004GuangxiChina

Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(s-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as s source and 1,8-diaminonaphthalene(DAN)as N source via an amination *** as-synthesized s-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-s doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon *** unique characteristics.endow s-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)sO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 ***,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical ***,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near Fen_(4)*** results evidently demonstrate that the dual effect of hard carbon substrate and s doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.

关键词： Transition metal-nitrogen-carbon Oxygen reduction reaction Hard carbon Amide based polymer reaction Proton exchange membrane cells

Degradation and biocompatibility of one-step electrodeposited magnesium thioctic acid/magnesium hydroxide hybrid coatings on ZE21B alloys for cardiovascular s.ents

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Journal of Magnesium and Alloys 2024年第1期12卷 120-138页

作者： Zhao-Qi Zhang Bing-Zhi Li pei-Duo Tong shao-kang Guan Li Wang Zheng-Hui Qiu Cun-Guo Lin Rong-Chang Zeng school of Material science and engineering&Henan Key Laboratory of Advanced Magnesium Alloy&Key Laboratory of Materials Processing and Mold Technology(Ministry of Education) Zhengzhou University100 Science RoadZhengzhou 450001China state Key Laboratory for Marine Corrosion and Protection Luoyang Ship Material Research InstituteQingdao 266101China Corrosion Laboratory for Light Metals College of Material Science and EngineeringShandong University of Science and TechnologyQingdao 266590China

Constructing a functional hybrid coating appears to be a promising strategy for addressing the poor corrosion resistance and insufficient endothelialization of Mg-based ***,the steps for preparing composite coatings are usually complicated and ***,a novel composite coating,composed of bioactive magnesium thioctic acid(MTA)layer formed by deposition and corrosion-resistant magnesium hydroxide(Mg(OH)_(2))layer grown in situ,is simply fabricated on ZE21B alloys via one-step *** electron microscopy(sEM)shows that the electrodeposited coating has a compact and uniform *** the high adhesion of the MTA/Mg(OH)_(2)hybrid coating is also confirmed by the micro-scratch *** test,scanning kelvin probe(sKP),and hydrogen evolution measurement indicate that the hybrid coating effectively reduces the degradation rate of Mg *** experiment and cell culture trial detect that the composite coating is of fine ***,the preparation mechanism of MTA/Mg(OH)_(2)hybrid coatings is discussed and *** coating shows a great potential application for cardiovascular s.ents.

关键词： Magnesium alloy Corrosion resistance Hybrid coating endothelialization Biocompatibility

Relationship between seismic structures and the diverse rupture processes of the 2023 Türkiye earthquake doublet

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science China Earth sciences 2024年第9期67卷 2810-2823页

作者： Zhi WANG Yi FU shunping pei CAs Key Laboratory of Ocean and Marginal sea Geology South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou 510301China southern Marine science and engineering Guangdong Laboratory(Guangzhou) Guangzhou 511458China Key Laboratory of Tibetan Plateau Earth system Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of sciences Beijing 100049China

Recent geodetic and seismological observations of two major earthquakes in southeastern Türkiye in February 2023 have revealed complex rupture initiation,propagation,and segmentation along the East Anatolian Fault Zone(EAFZ)and surrounding ***,the role of upper crust structures along the EAFZ in determining the diverse rupture processes of this earthquake doublet remains *** further investigate this,we employed double-difference location and seismic tomography techniques to determine high-resolution seismic velocities(V_(P),V_(s))and Poisson’s ratio(σ)structures using a multiparameter joint tomographic *** dataset includes 100,833 high-quality source-receiver travel-time pairs of P-and *** find that the unique rupture processes of this earthquake doublet were primarily influenced by contrasting crustal seismic structures and localized geological *** M_(w)7.8 mainshock was initiated within a transitional edge zone characterized by a rigid part(asperity)of the seismogenic zone with sharp contrast variations in rock strength ranging from low to high along the *** comparison,the M_(w)7.6 rupture originated in a ductile belt featuring fluid saturation with low-VP,low-Vs,and high-σvalues that extended parallel to the Cardak *** pronounced contrast structures observed along the former rupture can be attributed to the oblique collision system between the weakened section of the east Anatolian plateau and the brittle Arabian platform,while the latter rupture was initiated within the ductile structure associated with fluid intrusion caused by the northward subduction of the Cyprus slab and subsequent ***,the occurrence of the first earthquake(E1)serves to alleviate shear stress on the second earthquake(E2)fault,potentially impeding the initiation of an E2 *** the contrary,this event also significantly reduces the normal stress acting on the E2 fault due to a double left-lateral strike-slip system

关键词： 2023 Turkiye earthquake doublet Joint seismic tomography Tomographic transition edge seismic rupture process strong fault coupling

Research on Defect Detection ofWind Turbine Blades Based onMorphology and Improved Otsu Algorithm Using Infrared Images

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Computers, Materials and Continua 2024年第1期81卷 933-949页

作者： kang s. He Y. Li W. Liu s. school of Mechanical and Control engineering Baicheng Normal University Baicheng 137000 China school of Information and Control engineering Jilin Institute of Chemical Technology Jilin 132022 China

To address the issues of low accuracy and high false positive rate in traditional Otsu algorithm for defect detection on infrared images of wind turbine blades (WTB), this paper proposes a technique that combines morphological image enhancement with an improved Otsu algorithm. First, mathematical morphology's differential multi-scale white and black top-hat operations are applied to enhance the image. The algorithm employs.entropy as the objective function to guide the iteration process of image enhancement, selecting appropriate structural element scales to execute differential multi-scale white and black top-hat transformations, effectively enhancing the detail features of defect regions and improving the contrast between defects and background. Afterwards, grayscale inversion is performed on the enhanced infrared defect image to better adapt to the improved Otsu algorithm. Finally, by introducing a parameter K to adjust the calculation of inter-class variance in theOtsumethod, theweight of the target pixels is increased. Combined with the adaptive iterative threshold algorithm, the threshold selection process is further fine-tuned. Experimental results show that compared to traditional Otsu algorithms and other improvements, the proposed method has significant advantages in terms of defect detection accuracy and reducing false positive rates. The average defect detection rate approaches 1, and the average Hausdorff distance decreases to 0.825, indicating strong robustness and accuracy of the method. © 2024 The Authors.

关键词： adaptive iterative thresholding grayscale inversion improved Otsu algorithm infrared image Morphological enhancement

study on 6-DOF active vibration-isolation system of the ultra-precision turning lathe based on GA-BP-PID control for dynamic loads

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Advances in Manufacturing 2024年第1期12卷 33-60页

作者： Bo Wang Zhong Jiang pei-Da Hu Department of Precision Instrument Tsinghua UniversityBeijing100084People’s Republic of China Institute of Machinery Manufacturing Technology China Academy of Engineering PhysicsMianyang621900SichuanPeople’s Republic of China

The vibration disturbance from an external environment affects the machining accuracy of ultra-precision machining *** active vibration-isolation systems(AVIs)have been developed based on static *** a vibration-isolation load changes dynamically during ultra-precision turning lathe machining,the system parameters change,and the efficiency of the active vibration-isolation system based on the traditional control strategy *** solve this problem,this paper proposes a vibration-isolation control strategy based on a genetic algorithm-back propagation neural network-PID control(GA-BP-PID),which can automatically adjust the control parameters according to the machining ***-isolation simulations and experiments based on passive vibration isolation,a PID algorithm,and the GA-BP-PID algorithm under dynamic load machining conditions were *** experimental results demonstrated that the active vibration-isolation control strategy designed in this study could effectively attenuate vibration disturbances in the external environment under dynamic load *** design is reasonable and feasible.

关键词： Ultra-precision diamond turning lathe Active vibration isolation six degrees of freedom Dynamic load Genetic algorithm-back propagation neural network-PID(GA-BP-PID)control

The Association Between Preserved Ratio Impaired spirometry and Mortality –– 10 CKB study Areas, China, 2004–2022

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China CDC weekly 2024年第43期6卷 1120-1125,I0003页

作者： Yalei Ke Xinyi Zhang Dianjianyi sun pei pei Huaidong Du Yiping Chen Ling Yang Xiaoming Yang kang Wang Junshi Chen Zhengming Chen Jun Lv Liming Li Canqing Yu Department of Epidemiology and Biostatistics School of Public HealthPeking University Health Science CenterBeijingChina Peking University Center for Public Health and Epidemic Preparedness&Response BeijingChina Key Laboratory of Epidemiology of Major Diseases(Peking University) Ministry of EducationBeijingChina Clinical Trial service Unit&Epidemiological studies Unit(CTsU) Nuffield Department of Population HealthUniversity of OxfordOxfordUK shibei Center for Disease Control and Prevention Qingdao CityShandong ProvinceChina China National Center for Food safety Risk Assess.ent BeijingChina state Key Laboratory of Vascular Homeostasis and Remodeling Peking UniversityBeijingChina.

What is already known about this topic?China has the world’s most significant public health and economic burden of chronic respiratory ***,the association between preserved ratio impaired spirometry(PRIsm)and mortality risk is *** is added by this report?The PRIsm group exhibited a 37%higher risk of allcause mortality than the normal group,and the risks of death from cardiovascular diseases,neoplasms,respiratory diseases,and infectious and parasitic diseases were also increased in ***,the presence of respiratory symptoms or disease was associated with an increased risk of mortality in *** are the implications for public health practice?It is imperative to enhance public awareness of PRIsm and to implement measures to facilitate the regression of PRIsm toward normal lung function.

关键词： function. impaired neoplasms