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Cooperative User-Scheduling and Resource Allocation Optimization for Intelligent Reflecting Surface Enhanced LEO Satellite Communication

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China Communications 2024年第2期21卷 227-244页

作者： meng meng bo Hu Shanzhi Chen Jianyin zhang State Key Lab of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China State Key Lab of Wireless Mobile Communication China Academy of Telecommunication TechnologyBeijing 100191China Research Institute of China Mobile Beijing 100053China

Lower Earth Orbit(LEO) satellite becomes an important part of complementing terrestrial communication due to its lower orbital altitude and smaller propagation delay than Geostationary satellite. However, the LEO satellite communication system cannot meet the requirements of users when the satellite-terrestrial link is blocked by obstacles. To solve this problem, we introduce Intelligent reflect surface(IRS) for improving the achievable rate of terrestrial users in LEO satellite communication. We investigated joint IRS scheduling, user scheduling, power and bandwidth allocation(JIRPB) optimization algorithm for improving LEO satellite system *** optimization problem of joint user scheduling and resource allocation is formulated as a non-convex optimization problem. To cope with this problem, the nonconvex optimization problem is divided into resource allocation optimization sub-problem and scheduling optimization sub-problem firstly. Second, we optimize the resource allocation sub-problem via alternating direction multiplier method(ADMM) and scheduling sub-problem via Lagrangian dual method ***, we prove that the proposed resource allocation algorithm based ADMM approaches sublinear convergence theoretically. Finally, we demonstrate that the proposed JIRPB optimization algorithm improves the LEO satellite communication system throughput.

关键词： convex optimization intelligent reflecting surface LEO satellite communication OFDM

Investigation of hydroxyl-terminated polybutadiene propellant breaking characteristics and mechanism impacted by submerged cavitation water jet

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Defence Technology（防务技术） 2024年第3期33卷 559-572页

作者： Wenjun Zhou meng Zhao bo Liu Youzhi Ma Youzhi zhang Xuanjun Wang Zhijian Laboratory Rocket Force University of EngineeringXi’an710025China

A submerged cavitation water jet(SCWJ)is an effective method to recycle solid propellant from obsolete solid engines by the breaking *** propellant's breaking modes and mechanical process under SCWJ impact are *** study aims to understand those impact breaking *** hydroxyl-terminated polybutadiene(HTPB)propellant was chosen as the research material,and a self-designed test system was used to conduct impact tests at four different working *** high-speed camera characterized crack propagation,and the DIC method calculated strain change during the impact ***,micro and macro fracture morphologies were characterized by scanning electron microscope(SEM)and computed tomography(CT)*** results reveal that the compressive strain concentration region locates right below the nozzle,and the shear strain region distributes symmetrically with the jet axis,which increases to 4% at first 16th ms,the compressive strain rises to 2% and 6% in the axial and transverse direction,*** two tensile cracks formed first at the compression strain concentrate region,and there generate many shear cracks around the tensile cracks,and those shear cracks that develop and aggregate cause the cracks to become wider and cut through the tensile cracks,forming the tensile-shear cracks and the impact parts eventually *** HTPB propellant forms a breaking hole shaped conical after impact 10 *** mass loss increases by 17 times at maximum,with the working pressure increasing by three ***,the damage value of the breaking hole remaining on the surface increases by 7.8 times while 2.9 times in the depth of the breaking *** breaking efficiency is closely affected by working *** failure modes of HTPB impacted by SCWJ are classified as tensile crack-dominated and tensile-shear crack-dominated damage mechanisms.

关键词： Submerged cavitation water jet Hydroxyl-terminated polybutadiene propellant Breaking characteristics Failure modes

Applications of single-cell RNA sequencing in spermatogenesis and molecular evolution

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Zoological Research 2024年第3期45卷 575-585页

作者： Wen-bo Chen meng-Fei zhang Fan Yang Jin-Lian Hua College of Veterinary Medicine Shaanxi Centre of Stem Cells Engineering&TechnologyNorthwest A&F UniversityYanglingShaanxi 712100China Key Laboratory of Livestock Biology Northwest A&F UniversityYanglingShaanxi 712100China

Spermatogenic cell heterogeneity is determined by the complex process of spermatogenesis ***,effectively revealing the regulatory mechanisms underlying mammalian spermatogenic cell development and differentiation via traditional methods is *** in technology have led to the emergence of many single-cell transcriptome sequencing protocols,which have partially addressed these *** this review,we detail the principles of 10x Genomics technology and summarize the methods for downstream analysis of single-cell transcriptome sequencing ***,we explore the role of single-cell transcriptome sequencing in revealing the heterogeneity of testicular ecological niche cells,delineating the establishment and disruption of testicular immune homeostasis during human spermatogenesis,investigating abnormal spermatogenesis in humans,and,ultimately,elucidating the molecular evolution of mammalian spermatogenesis.

关键词： Single-cell RNA sequencing(scRNA-seq) Spermatogenesis Molecular evolution Sertoli cell

Corrugated Graphene Paper Reinforced Silicone Resin Composite for Efficient Interface Thermal Management

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Chinese Journal of Polymer Science 2024年第7期42卷 1002-1014,I0010页

作者： bo-Wen Wang Heng zhang Qing-Xia He Hui-Tao Yu meng-meng Qin Wei Feng Tianjin Key Laboratory of Composite and Functional Materials School of Materials Science and EngineeringTianjin UniversityTianjin300350China International Engineering Institute Tianjin UniversityTianjin300350China

With the rapid development of high-power-density electronic devices,interface thermal resistance has become a critical barrier for effective heat management in high-performance electronic ***,there is an urgent demand for advanced thermal interface materials(TIMs)with high cross-plane thermal conductivity and excellent compressibility to withstand increasingly complex operating *** achieve this aim,a promising strategy involves vertically arranging highly thermoconductive graphene on ***,with the currently available methods,achieving a balance between low interfacial thermal resistance,bidirectional high thermal conductivity,and large-scale production is ***,we prepared a graphene framework with continuous filler structures in in-plane and cross-plane directions by bonding corrugated graphene to planar graphene *** interface interaction between the graphene paper framework and polymer matrix was enhanced via surface functionalization to reduce the interface thermal *** resulting three-dimensional thermal framework endows the polymer composite material with a cross-plane thermal conductivity of 14.4 W·m^(-1)·K^(-1)and in-plane thermal conductivity of 130W·m^(-1)·K^(-1)when the thermal filler loading is 10.1 wt%,with a thermal conductivity enhancement per 1 wt%filler loading of 831%,outperforming various graphene structures as *** its high thermal conductivity,low contact thermal resistance,and low compressive modulus,the developed highly thermoconductive composite material demonstrates superior performance in TIM testing compared with TFLEX-700,an advanced commercial TIM,effectively solving the interfacial heat transfer issues in electronic *** novel filler structure framework also provides a solution for achieving a balance between efficient thermal management and ease of processing.

关键词： Graphene paper Vertically aligned structure Cross-plane thermal conductivity Low compressive modulus Thermal interface material

Multi-distortion suppression for neutron radiographic images based on generative adversarial network

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Nuclear Science and Techniques 2024年第4期35卷 176-188页

作者： Cheng-bo meng Wang-Wei Zhu Zhen zhang Zi-Tong Wang Chen-Yi Zhao Shuang Qiao Tian zhang School of Physics Northeast Normal UniversityChangchun 130024China

Neutron radiography is a crucial nondestructive testing technology widely used in the aerospace,military,and nuclear ***,because of the physical limitations of neutron sources and collimators,the resulting neutron radiographic images inevitably exhibit multiple distortions,including noise,geometric unsharpness,and white ***,these distortions are particularly significant in compact neutron radiography systems with low neutron ***,in this study,we devised a multi-distortion suppression network that employs a modified generative adversarial network to improve the quality of degraded neutron radiographic *** neutron radiographic image datasets with various types and levels of distortion were built for the first time as multi-distortion suppression ***,the coordinate attention mechanism was incorporated into the backbone network to augment the capability of the proposed network to learn the abstract relationship between ideally clear and degraded *** experiments were performed;the results show that the proposed method can effectively suppress multiple distortions in real neutron radiographic images and achieve state-of-theart perceptual visual quality,thus demonstrating its application potential in neutron radiography.

关键词： Neutron radiography Multi-distortion suppression Generative adversarial network Coordinate attention mechanism

Construction of shallow buried large-span metro stations using the small pipe roof-beam method

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Frontiers of Structural and Civil Engineering 2024年第1期18卷 122-136页

作者： Qian BAI Wen ZHAO Yingda zhang Pengjiao JIA Xiangrui meng bo LU Xin WANG Dazeng SUN School of Resources and Civil Engineering Northeastern UniversityShenyang 110819China Centre for Infrastructure Engineering and Safety School of Civil and Environmental EngineeringThe University of New South WalesNSW 2052Australia School of Rail Transportation Soochow UniversitySuzhou 215131China China Northeast Architectural Design and Research Institute Co. Ltd.Shenyang 110006China

In relation to the Shifu Road Station project on Line 4 of the Shenyang Metro in China,a small-pipe roof-beam method for constructing subway stations is ***,a numerical simulation was performed to optimize the supporting parameters of the proposed method and determine the design ***,the deformation of the pipe roof and surface settlement during the construction process were ***,the surface settlement attributed to the excavation was studied through field monitoring,and the proposed method was compared with other *** results show that an increase in the pipe-roof spacing has little effect on the surface settlement and piperoof *** bearing capacity of the pipe roof can be efficiently utilized once the flexural stiffness reaches 2EI,and the flexural stiffness is not the dominant factor controlling the *** essential stages in controlling surface settlement are the excavations of the transverse pilot tunnels and the soil between *** final settlement value of the ground was 24.1 mm,resulting in a reduction in the construction period by at least five months while satisfying the control requirements.

关键词： subway station pipe-roof method surface settlement simulation on-site monitoring

Continuous-wave operation of 1550 nm low-threshold triple-lattice photonic-crystal surface-emitting lasers

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Light(Science & Applications) 2024年第3期13卷 446-453页

作者： Ziye Wang Xia Liu Pinyao Wang Huanyu Lu bo meng Wei zhang Lijie Wang Yanjing Wang Cunzhu Tong State Key Laboratory of Luminescence and Applications Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Central Research Institute Planning Dept 2012 LabsHuawei Technologies Company Ltd.Shenzhen 518129China

Benefitting from narrow beam divergence,photonic crystal surface-emitting lasers are expected to play an essential role in the ever-growing fields of optical communication and light detection and *** operating with 1.55μm wavelengths have attracted particular attention due to their minimum fiber loss and high eye-safe ***,high interband absorption significantly decreases their performance at this 1.55μm ***,stronger optical feedback is needed to reduce their threshold and thus improve the output *** this goal,photonic-crystal resonators with deep holes and high dielectric contrast are often ***,the relevant techniques for high-contrast photonic crystals inevitably complicate fabrication and reduce the final *** this paper,we demonstrate the first continuous-wave operation of 1.55μm photonic-crystal surface-emitting lasers by using a‘triple-lattice photonic-crystal resonator’,which superimposes three lattice point groups to increase the strength of in-plane optical *** this geometry,the in-plane 180°coupling can be enhanced threefold compared to the normal single-lattice *** theoretical and experimental investigations demonstrate the much lower threshold current density of this structure compared to‘single-lattice’and‘double-lattice’photonic-crystal resonators,verifying our design *** findings provide a new strategy for photonic crystal laser miniaturization,which is crucial for realizing their use in future high-speed applications.

关键词： resonator crystal lattice

Polyetherketoneketone/carbon fiber composites with an amorphous interface prepared by solution impregnation

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新型炭材料（中英文） 2024年第4期39卷 692-702页

作者： zhang Feng LI bo-lan JIAO meng-xiao LI Yan-bo WANG Xin YANG Yu YANG Yu-qiu zhang Xiao-hua MOE Key Laboratory of Textile Science&Technology College of TextilesInnovation Center for Textile Science and TechnologyDonghua UniversityShanghai 201620China Key Laboratory of Carbon Materials National Engineering Laboratory for Carbon Fiber TechnologyInstitute of Coal ChemistryChinese Academy of SciencesTaiyuan 030001China

Interfacial adhesion between carbon fibers(CF)and polyetherketoneketone(PEKK)is a key factor that affects the mechanical performances of their *** is therefore of great importance to impregnate the CF bundles with PEKK as effi-ciently as *** report that PEKK with a good dispersion in a mixed solution of 4-chlorophenol and 1,2-dichloroethane can be introduced onto CF surfaces by solution impregnation and curing at 280,320,340 and 360℃.The excellent wettability or infiltra-tion of the PEKK solution guarantees a full covering and its tight binding to CFs,making it possible to evaluate the interfacial shear strength(IFSS)with the microdroplet *** interior of the CF bundles is completely and uniformly filled with PEKK by solu-tion impregnation,leading to a high interlaminar shear strength(ILSS).The maximum IFSS and ILSS reached 107.8 and 99.3 MPa,*** superior shear properties are ascribed to the formation of amorphous PEKK in the small spaces between CFs.

关键词： Polyetherketoneketone Carbon fiber Wettability Amorphous adhesion Interfacial strength

Organic Matter Accumulation in the Upper Permian Dalong Formation from the Lower Yangtze Region,South China

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Acta Geologica Sinica(English Edition) 2024年第1期98卷 150-167页

作者： FANG Chaogang zhang Chengcheng meng Guixi XU Jinlong XU Naicen LI Hualing LIU Mu LIU bo Institute of International Rivers and Eco-Security Yunnan UniversityKunming 650500China Nanjing Center China Geological SurveyNanjing 210016China Exploration Research Institute Anhui Provincial Bureau of Coal GeologyHefei 230088China China United Coalbed Methane Corporation Ltd. Beijing 100015China Geological Survey of Anhui Province Hefei 230001China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China

The Late Permian was marked by a series of important geological events and widespread organic-rich black shale depositions,acting as important unconventional hydrocarbon source ***,the mechanism of organic matter(OM)enrichment throughout this period is still *** on geochemical data,the marine redox conditions,paleogeographic and hydrographic environment,primary productivity,volcanism,and terrigenous input during the Late Permian in the Lower Yangtze region have been studied from the Putaoling section,Chaohu,to provide new insights into OM *** Phases are distinguished based on the TOC and environmental *** Phase I,anoxic conditions driven by water restriction enhanced OM *** Phase II,euxinic and cycling hydrological environments were the two most substantial controlling factors for the massive OM *** Phase III,intensified terrestrial input potentially diluted the OM in sediment and the presence of oxygen in bottom water weakened the preservation *** IV was characterized by a relatively higher abundance of mercury(Hg)and TOC(peak at 16.98 wt%),indicating that enhanced volcanism potentially stimulated higher productivity and a euxinic *** Phase V,extremely lean OM was preserved as a result of terrestrial dilutions and decreasing primary *** I,II and IV are characterized as the most prominent OM-rich zones due to the effective interactions of the controlling factors,namely paleogeographic,hydrographic environment,volcanism,and redox conditions.

关键词： geochemistry redox condition primary productivity OM accumulation Lopingian/Changhsingian Lower Yangtze region