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Reinforcement learning based dynamic distributed routing scheme for mega LEO satellite networks

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Chinese Journal of Aeronautics 2023年第2期36卷 284-291页

作者： Yixin huang Shufan WU Zeyu kang Zhongcheng MU Hai huang Xiaofeng WU Andrew Jack TANG Xuebin CHENG School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China School of Astronautics Beihang UniversityBeijing 100191China School of Aerospace Mechanical and Mechatronic EngineeringThe University of SydneyCamperdown 2006Australia X-Laboratory The Second Academy of China Aerospace Science and Industry CorporationBeijing 100854China

Recently,mega Low Earth Orbit(LEO)Satellite Network(LSN)systems have gained more and more attention due to low latency,broadband communications and global coverage for ground *** of the primary challenges for LSN systems with inter-satellite links is the routing strategy calculation and maintenance,due to LSN constellation scale and dynamic network topology *** order to seek an efficient routing strategy,a Q-learning-based dynamic distributed Routing scheme for LSNs(QRLSN)is proposed in this *** achieve low end-toend delay and low network traffic overhead load in LSNs,QRLSN adopts a multi-objective optimization method to find the optimal next hop for forwarding data *** results demonstrate that the proposed scheme can effectively discover the initial routing strategy and provide long-term Quality of Service(QoS)optimization during the routing maintenance *** addition,comparison results demonstrate that QRLSN is superior to the virtual-topology-based shortest path routing algorithm.

关键词： LEO satellite networks Mega constellation Multi-objective optimization Routing algorithm Reinforcement learning

Two-dimensional hydrodynamic robust numerical model of soil erosion based on slopes and river basins

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Journal of Arid Land 2021年第10期13卷 995-1014页

作者： kang Yongde huang Miansong HOU Jingming TONG Yu PAN Zhanpeng State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China School of Water Resources and Hydroelectric EngineeringXi'an University of TechnologyXi'an 710048China Beijing Capital Eco-Environment Protection Group Co.Ltd. Beijing 100028China

Erosion is an important issue in soil science and is related to many environmental problems,such as soil erosion and sediment *** a simulation model suitable for soil erosion prediction is of great significance not only to accurately predict the process of soil separation by runoff,but also improve the physical model of soil *** this study,we develop a graphic processing unit(GPU)-based numerical model that combines two-dimensional(2D)hydrodynamic and Green-Ampt(G-A)infiltration modelling to simulate soil erosion.A Godunov-type scheme on a uniform and structured square grid is then generated to solve the relevant shallow water equations(SWEs).The highlight of this study is the use of GPU-based acceleration technology to enable numerical models to simulate slope and watershed erosion in an efficient and high-resolution *** results show that the hydrodynamic model performs well in simulating soil erosion *** erosion is studied by conducting calculation verification at the slope and basin *** first case involves simulating soil erosion process of a slope surface under indoor artificial rainfall conditions from 0 to 1000 s,and there is a good agreement between the simulated values and the measured values for the runoff *** second case is a river basin experiment(Coquet River Basin)that involves watershed *** of the erosion depth change and erosion cumulative amount of the basin during a period of 1-40 h show an elevation difference of erosion at 0.5-3.0 m,especially during the period of 20-30 *** cross sections in the basin are selected for simulation and the results reveal that the depth of erosion change value ranges from-0.86 to-2.79 m and the depth of deposition change value varies from 0.38 to 1.02 *** findings indicate that the developed GPU-based hydrogeomorphological model can reproduce soil erosion *** results are valuable for rainfall runoff and soil erosion predictions

关键词： soil erosion two-dimensional modelling rainfall runoff Green-Ampt model gully erosion

Research progress on Na_(3)V_(2)(PO_(4))_(2)F_(3)-based cathode materials for sodium-ion batteries

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Chinese Chemical Letters 2023年第6期34卷 7-17页

作者： kang Liang Daxiong Wu Yurong Ren Xiaobing huang Jianmin Ma School of Materials Science and Engineering Jiangsu Province Engineering Research Center of Intelligent Manufacturing Technology for the New Energy Vehicle Power BatteryChangzhou UniversityChangzhou 213164China School of Physics and Electronics Hunan UniversityChangsha 410082China College of Chemistry and Materials Engineering Hunan University of Arts and ScienceChangde 415000China School of Chemistry Tiangong UniversityTianjin 300387China

Sodium-ion batteries(SIBs)have received significant attention in large-scale energy storage due to their low cost and abundant *** obtain high-performance SIBs,many intensive studies about electrode materials have been carried out,especially the cathode *** various types of cathode material for SIBs,a 3D open framework structural Na_(3)V_(2)(PO_(4))_(2)F_(3)(NVPF)with Na superionic conductor(NASICON)structure is a promising cathode material owing to its high operating potential and high energy ***,its electrochemical properties are severely limited by the poor electronic conductivity due to the insulated[PO_(4)]tetrahedral *** this review,the challenges and strategies for NVPF are presented,and the synthetic strategy for NVPF is also analyzed in ***,recent developments of modification research to enhance their electrochemical performance are discussed,including designing the crystal structure,adjusting the electrode structure,and optimizing the electrolyte ***,further research and application for future development of NVPF are prospected.

关键词： Sodium-ion batteries Na_(3)V_(2)(PO_(4))_(2)F_(3) Synthetic strategy Electrochemical performance Energy storage

TIMP1 preserves the blood-brain barrier through interacting with CD63/integrin β1 complex and regulating downstream FAK/RhoA signaling

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Acta Pharmaceutica Sinica B 2020年第6期10卷 987-1003页

作者： Jingshu Tang Yuying kang Longjian huang Lei Wu Ying Peng State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences&Peking Union Medical CollegeBeijing 100050China

Blood-brain barrier(BBB)breakdown and the associated microvascular hyperpermeability are hallmark features of several neurological disorders,including traumatic brain injury(TBI).However,there is no viable therapeutic strategy to rescue BBB *** inhibitor of metalloproteinase-1(TIMP1)has been considered to be beneficial for vascular integrity,but the molecular mechanisms underlying the functions of TIMP1 remain ***,we report that TIMP1 executes a protective role on neuroprotective function via ameliorating BBB disruption in mice with experimental *** human brain microvessel endothelial cells(HBMECs)exposed to hypoxia and inflammation injury,the recombinant TIMP1(rTIMP1)treatment maintained integrity of junctional proteins and trans-endothelial ***,TIMP1 interacts with CD63/integrinβ1 complex and activates downstream FAK signaling,leading to attenuation of RhoA activation and F-actin depolymerization for endothelial cells structure ***,these effects depend on CD63/integrinβ1 complex,instead of the MMP-inhibitory ***,our results identified a novel MMP-independent function of TIMP1 in regulating endothelial barrier *** interventions targeting TIMP1 and its downstream signaling may be beneficial to protect BBB function following brain injury and neurological disorders.

关键词： Tissue inhibitor of metalloproteinase-1 Blood-brain barrier Junctional proteins CD63 Integrinβ1

Comparison of surface integrity for dry and wet drilling of 49Fe-49Co-2V alloy

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Chinese Journal of Aeronautics 2022年第6期35卷 325-338页

作者： Yuan ZHANG Zhigang DONG Yan BAO Renke kang Xin huang Dongming GUO Key Laboratory for Precision and Non-traditional Machining Technology of the Ministry of Education School of Mechanical EngineeringDalian University of TechnologyDalian 116024China AVIC Xi’an Flight Automatic Control Research Institute Xi’an 710076China

Working performances of the components made out of 49Fe-49Co-2V alloy are closely related to the surface integrity of the drilled holes,which are influenced remarkably by the cooling *** present study focuses on the surface integrity differences between wet and dry drilled 49Fe-49Co-2V alloy *** drilled hole surface roughness and topographies,metallurgical and mechanical properties,and the exit characterizations were obtained using optical microscopy(OM),scanning electron microscopy(SEM),electron backscatter diffraction microscopy(EBSD),transmission electron microscopy(TEM),energy dispersive spectroscopy(EDS)and Vickers hardness techniques,*** effects of cooling conditions on the surface integrity were concluded and the influence mechanisms were analyzed based on the force and temperature differences in drilling process with different cooling *** is found that the surface roughness and the thickness of refined-grain region of the dry drilled holes are larger than those of wet drilled holes;work hardening induced by wet drilling is more serious than dry drilling;chippings occurred in the exits of the wet drilled holes due to the material brittleness,which could be avoided by dry *** surface integrity differences of wet and dry drilled holes are closely related to the force and temperature differences in drilling process with different cooling conditions.

关键词： 49Fe-49Co-2V alloy Cooling condition Drilling Exit chipping Microstructure Surface integrity Surface quality Work hardening

A Survey on Performance Optimization of High-Level Synthesis Tools

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Journal of Computer Science & Technology 2020年第3期35卷 697-720页

作者： Lan huang Da-Lin Li kang-Ping Wang Teng Gao Adriano Tavares College of Computer Science and Technology Jilin UniversityChangchun 130012China Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education Jilin University Changchun 130012China Zhuhai Laboratory of Key Laboratory of Symbol Computation and Knowledge Engineering of Ministry of Education Zhuhai College of Jilin University Zhuhai 519041China Algorithm Center University of MinhoGuimaraes 4800058Portugal

Field-programmable gate arrays(FPGAs)have recently evolved as a valuable component of the heterogeneous *** register transfer level(RTL)design flows demand the designers to be experienced in hardware,resulting in a possible failure of ***-level synthesis(HLS)permits designers to work at a higher level of abstraction through synthesizing high-level language programs to RTL *** provides a promising approach to solve these ***,the performance of HLS tools still has *** example,designers remain exposed to various aspects of hardware design,development cycles are still time consuming,and the quality of results(QoR)of HLS tools is far behind that of RTL *** this paper,we survey the literature published since 2014 focusing on the performance optimization of HLS *** with previous work,we extend the scope of the performance of HLS tools,and present a set of three-level evaluation criteria,covering from ease of use of the HLS tools to promotion on specific metrics of *** also propose performance evaluation equations for describing the relation between the performance optimization and the *** find that it needs more efforts on the ease of use for efficient HLS *** suggest that it is better to draw an analogy between the HLS development process and the embedded system design process,and to provide more elastic HLS methodology which integrates FPGAs virtual machines.

关键词： evaluation criterion field-programmable gate array(FPGA) high-level synthesis(HLS) performance optimization quality of results(QoR)

Influence of post-heat treatment on the microstructure and mechanical properties of Al-Cu-Mg-Zr alloy manufactured by selective laser melting

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Journal of Materials Science & Technology 2022年第16期111卷 35-48页

作者： Yanfang Wang Xin Lin Nan kang Zihong Wang Yuxi Liu Weidong huang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

The properties of modified conventional wrought aluminum alloys cannot be significantly enhanced by normal post-heat treatment in that the fine-grained strengthening,arising from high cooling rate in SLM,is *** this work,compared with the normal T6 heat treatment,a novel simple direct aging regime was proposed to maintain the grain-boundary strengthening and to utilize the precipitation strengthening of secondary *** was found that a heterogeneous grain structure,which consisted of ultrafine equiaxed(~0.82μm)and columnar(~1.80μm)grains at the bottom and top of molten pool,respectively,was formed in the SLM processed *** direct aging(DA),the ultrafine grains were maintained and a mass of spherical coherent L1-AlZr particles with a mean radius of approximately1.15 nm was *** contrast,after solution treatment and aging(STA),a significant grain coarsening occurred in the equiaxed grain ***,the coarsening L1-AlZr particles,nano-sized S phases and GPB zones were detected in the STA *** subsequently induced that the yield strength of the DA sample(~435 MPa)was higher than that of the STA sample(~402 MPa)owing to the grain boundary strengthening and precipitation *** the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6 alloy(~393 MPa).Both the STA and DA samples exhibited a higher strength than that of the other SLMed Al-Cu-Mg series alloys;this was comparable to that of the wrought AA2024-T6alloy(~393 MPa).

关键词： Selective laser melting Al-Cu-Mg alloy Heat treatment Microstructure Mechanical properties

Influence of travel speed on microstructure and mechanical properties of wire + arc additively manufactured 2219 aluminum alloy

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Journal of Materials Science & Technology 2020年第2期37卷 143-153页

作者： Yinghui Zhou Xin Lin Nan kang Weidong huang Jiang Wang Zhennan Wang State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Key Laboratory of Metal High Performance Additive Manufacturing and Innovative Design MIIT ChinaNorthwestern Polytechnical UniversityXi’an 710072China

Wire+arc additive manufacturing(WAAM)was preliminarily employed to fabricate the 2219 aluminum *** influence of the electric arc travel speed(TS)on the macro-morphology,microstructure,and mechanical properties were *** results indicated that as the electric arc TS increased,the size and the volume fraction of equiaxed grain *** high arc TS during WAAM also promoted the precipitation of theθ(Al2Cu)*** volume fractions ofθ’’andθ’phases reached maximum values when TS is 350 and 250 mm/min,*** thermal cycle facilitated the precipitation of theθ’*** addition,the micro-hardness and tensile strength of the alloy were analyzed,and the results indicated that samples fabricated at TS of 350 mm/min possessed finer equiaxed grain and exhibited higher ultimate tensile strength(273.5 MPa)and yield strength(182.9 MPa)compared to those fabricated at 250 mm/min.

关键词： Wire+arc additive manufacturing 2219 aluminum alloy Microstructure Mechanical properties

Erosion behavior of a ship propeller material of QAl9-4 alloy

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Rare Metals 2023年第7期42卷 2390-2395页

作者： Wei-Jiu huang Yong-Tao Zhou Zhen-Guo Wang Zhi-kang Liao School of Materials Science and Engineering Chongqing University of TechnologyChongqing400054China School of Materials Science and Engineering Beihang UniversityBeijing100191China

The erosion behavior of a QA19-4 alloy as a ship propeller material was *** effects of the solution,the impact angles and the sand content were *** test results demonstrate that the mass loss of the alloy in 3.5 wt%NaCl solution is 1.35 times that in tap water,due to the corrosive effect of Cl^(-).The mass loss of the alloy increases as the impact angle increases up to~30°and consequently decreases as the impact angle ***,this feature is typical for the ductile metal *** the impact angle of 0°,this feature is associated with the predominant erosion mechanisms,such as shallow plowing and surface fatigue;at 30°,this feature is micro-cutting,deep plowing and surface fatigue;and at 45°,it becomes indentation accompanied by extruded *** mass loss and surface roughness of the alloy increase as the sand content increases under the testing conditions.

关键词： Erosion QAl9-4 alloy Impact angle Sand content Erode surface