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Friction 2024年第2期12卷 291-304页

作者： Qingwen DAI lei CHEN Jiabao PAN Liping SHI Dameng liu Wei HUANG Xiaolei WANG College of Mechanical and Electrical Engineering Nanjing University of Aeronautics&AstronauticsNanjing 210016China State Key Laboratory of Tribology in Advanced Equipment Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China School of Mechanical Engineering Anhui Polytechnic UniversityWuhu 241000China School of Mechanical Engineering Anhui University of TechnologyMa’anshan 243032China

Robust superhydrophobic surfaces with excellent capacities of repelling water and anti-frosting are of importance for many mechanical *** this work,wear-resistant superhydrophobic surfaces were fabricated by curing a mixture of polyurethane acrylate(PUA)coating and 1H,1H,2H,2H-Perfluorodecyltrichlorosilane(HFTCS)on titanium alloy(TC4)surfaces decorated with micropillars pattern,thus,composite functional surfaces with PUA coating in the valleys around the micropillars pattern of TC4 were *** contact angle on fabricated surfaces could reach 167°.Influences of the geometric parameters of micropillars pattern on the apparent contact angle were investigated,and the corresponding wear-resistant property was *** impact and anti-frosting performances on the prepared surfaces were *** optimized design of surface texture with robust superhydrophobicity,controllable droplet impact,and anti-frosting performances was *** design principle is of promising prospects for fabricating superhydrophobic surfaces in traditional mechanical systems.

关键词： surface texture robust superhydrophobic wear-resistant droplet impact anti-frosting

MXene Hollow Spheres Supported by a C–Co Exoskeleton Grow MWCNTs for Efficient Microwave Absorption

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Nano-Micro Letters 2024年第6期16卷 76-94页

作者： Ze Wu Xiuli Tan Jianqiao Wang Youqiang Xing Peng Huang Bingjue Li lei liu School of Mechanical Engineering Southeast UniversityNanjing 211189People’s Republic of China

High-performance microwave absorption(MA) materials must be studied immediately since electromagnetic pollution has become a problem that cannot be disregarded. A straightforward composite material, comprising hollow MXene spheres loaded with C–Co frameworks, was prepared to develop multiwalled carbon nanotubes(MWCNTs). A high impedance and suitable morphology were guaranteed by the C–Co exoskeleton, the attenuation ability was provided by the MWCNTs endoskeleton, and the material performance was greatly enhanced by the layered core–shell structure. When the thickness was only 2.04 mm, the effective absorption bandwidth was 5.67 GHz, and the minimum reflection loss(RLmin) was-70.70 d B. At a thickness of 1.861 mm, the sample calcined at 700 ℃ had a RLmin of-63.25 d B. All samples performed well with a reduced filler ratio of 15 wt%. This paper provides a method for making lightweight core–shell composite MA materials with magnetoelectric synergy.

关键词： MXene C-Co skeleton MWCNTs Microwave absorption

Numerical investigation of geostress influence on the grouting reinforcement effectiveness of tunnel surrounding rock mass in fault fracture zones

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 81-101页

作者： Xiangyu Xu Zhijun Wu lei Weng Zhaofei Chu Quansheng liu Yuan Zhou The Key Laboratory of Safety for Geotechnical and Structural Engineering of Hubei Province School of Civil EngineeringWuhan UniversityWuhan430072China Wuhan University Shenzhen Research Institute Shenzhen518057China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China Institute of Rock and Soil Mechanics Chinese Academy of SciencesWuhan430071China

Grouting is a widely used approach to reinforce broken surrounding rock mass during the construction of underground tunnels in fault fracture zones,and its reinforcement effectiveness is highly affected by *** this study,a numerical manifold method(NMM)based simulator has been developed to examine the impact of geostress conditions on grouting reinforcement during tunnel *** develop this simulator,a detection technique for identifying slurry migration channels and an improved fluid-solid coupling(FeS)framework,which considers the influence of fracture properties and geostress states,is developed and incorporated into a zero-thickness cohesive element(ZE)based NMM(Co-NMM)for simulating tunnel ***,to simulate coagulation of injected slurry,a bonding repair algorithm is further proposed based on the ZE *** verify the accuracy of the proposed simulator,a series of simulations about slurry migration in single fractures and fracture networks are numerically reproduced,and the results align well with analytical and laboratory test ***,these numerical results show that neglecting the influence of geostress condition can lead to a serious over-estimation of slurry migration range and reinforcement *** validations,a series of simulations about tunnel grouting reinforcement and tunnel excavation in fault fracture zones with varying fracture densities under different geostress conditions are *** on these simula-tions,the influence of geostress conditions and the optimization of grouting schemes are discussed.

关键词： Numerical manifold method(NMM) Grouting reinforcement Geostress condition Fault fracture zone Tunnel excavation

Revisiting the island of hexadecapoledeformation nuclei in the A≈150 mass region:focusing on the model application to nuclear shapes and masses

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Communications in Theoretical Physics 2024年第2期76卷 74-88页

作者： Xiao-Yang Wei Hua-lei Wang Zhen-Zhen Zhang Min-Liang liu School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China Key Laboratory of High Precision Nuclear Spectroscopy Institute of Modern PhysicsChinese Academy of SciencesLanzhou 730000China School of Nuclear Science and Technology University of Chinese Academy of SciencesBeijing 100049China

Based on the potential-energy-surface calculation,the impact of different deformation degrees of freedom on a single-particle structure and binding energies in nuclei around^(152)Nd,located on one of the hexadecapole-deformation islands,is analyzed in a multi-dimensional deformation *** energy maps,curves and tables are presented to indicate nuclear *** calculated equilibrium deformations and binding energies with different potential parameters are compared with experimental data and other *** is found that the inclusion of the hexadecapole deformations,especially the axial one,can improve the theoretical description of both nuclear shapes and *** addition,our calculated potential-energy curve shows that a critical deformation-point,β_(2)≈0.4,exists—the triaxial(hexadecapole)deformation effect can be neglectable but the hexadecapole(triaxial)one plays an important role before(after)such a critical point.

关键词： hexadecapole deformation binding energy potential-energy-surface calculation nuclear property

Task-Oriented Semantic Communication with Foundation Models

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China Communications 2024年第7期21卷 65-77页

作者： Chen Mingkai liu Minghao Zhang Zhe Xu Zhiping Wang lei Key Laboratory of Broadband Wireless Communication and Sensor Network Technology Ministry of EducationNanjing University of Posts and TelecommunicationsNanjing 210003China School of Ocean Information Engineering Jimei UniversityXiamen 361021China Key Laboratory of Underwater Acoustic Communication and Marine Information Technology(Xiamen University) Ministry EducationXiamen 361005China

In the future development direction of the sixth generation(6G)mobile communication,several communication models are proposed to face the growing challenges of the *** rapid development of artificial intelligence(AI)foundation models provides significant support for efficient and intelligent communication *** this paper,we propose an innovative semantic communication paradigm called task-oriented semantic communication system with foundation ***,we segment the image by using task prompts based on the segment anything model(SAM)and contrastive language-image pretraining(CLIP).Meanwhile,we adopt Bezier curve to enhance the mask to improve the segmentation ***,we have differentiated semantic compression and transmission approaches for segmented ***,we fuse different semantic information based on the conditional diffusion model to generate high-quality images that satisfy the users'specific task ***,the experimental results show that the proposed system compresses the semantic information effectively and improves the robustness of semantic communication.

关键词： diffusion model foundation model joint source-channel coding task-oriented semantic communication

A thermal stress loading technique for large-sized hot dry rock mechanical tests

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Deep Underground Science and Engineering 2024年第3期3卷 326-337页

作者： Huiling Ci Bing Bai Hongwu lei Yan Zou Jianfeng liu State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhanChina University of Chinese Academy of Sciences BeijingChina State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengduChina

Testing of large-sized specimens is becoming increasingly important in deep underground rock mechanics and *** traditional mechanical loading,stresses on large-sized specimens are achieved by large host frames and hydraulic pumps,which could lead to great ***-cost testing machines clearly always have great *** this study,a new approach is proposed using thermal expansion stress to load rock specimens,which may be particularly suitable for tests of deep hot dry rock with high *** is a different technical route from traditional mechanical loading through hydraulic *** the rock mechanics test system of hot dry rock that already has an investment in heating systems,this technology may reduce the cost of the loading subsystem by fully utilizing the temperature *** paper presents the basic principle and a typical design of this technical *** feasibility analysis is then conducted based on numerical *** some technical details still need to be resolved,the feasibility of this loading approach has been preliminarily confirmed.

关键词： deep rock engineering high-temperature and high-stress conditions hot dry rock large-sized model test thermal stress loading

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Heteroatoms doped iron oxide-based catalyst prepared from zinc slag for efficient selective catalytic reduction of NO_(x) with NH_(3)

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International Journal of Coal Science & Technology 2024年第1期11卷 180-193页

作者： Jiale Liang Yaojun Zhang Hao Chen Licai liu Panyang He lei Wu College of Materials Science and Engineering Xi’an University of Architecture and TechnologyXi’an710055China School of Chemistry and Chemical Engineering Xi’an University of Architecture and TechnologyXi’an710055China School of Resources Engineering Xi’an University of Architecture and TechnologyXi’an710055China

Excessive emissions of nitrogen oxides from flue gas have imposed various detrimental impacts on environment,and the development of deNO_(x) catalysts with low-cost and high performance is an urgent *** oxide-based material has been explored for promising deNO_(x) ***,the unsatisfactory low-temperature activity limits their practical *** this study,a series of excellent low-temperature denitrification catalysts(Ha-FeO_(x)/yZS)were prepared by acid treatment of zinc slag,and the mass ratios of Fe to impure ions was regulated by adjusting the acid ***-FeO_(x)/yZS showed high denitrification performance(>90%)in the range of 180–300℃,and the optimal NO conversion and N2 selectivity were higher than 95%at 250℃.Among them,the Ha-FeO_(x)/2ZS synthesized with 2 mol/L HNO3 exhibited the widest temperature window(175–350℃).The excellent denitrification performance of Ha-FeO_(x)/yZS was mainly attributed to the strong interaction between Fe and impurity ions to inhibit the growth of crystals,making Ha-FeO_(x)/yZS with amorphous structure,nice fine particles,large specific surface area,more surface acid sites and high chemisorbed *** in-situ DRIFT experiments confirmed that the SCR reaction on the Ha-FeO_(x)/yZS followed both Langmuir-Hinshelwood(L-H)mechanism and Eley-Rideal(E-R)*** present work proposed a high value-added method for the preparation of cost-effective catalysts from zinc slag,which showed a promising application prospect in NO_(x) removal by selective catalytic reduction with ammonia.

关键词： Flue gas NO_(x)removal Zinc slag-derived catalyst NH_(3)-SCR Catalysis activity

Effects of rare earth elements on inclusions, microstructure and impact toughness of spring steel

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Journal of Iron and Steel Research International 2024年第4期31卷 933-944页

作者： Chun-lei Hao Chao-yun Yang Peng liu Yi-kun Luan Bao-guang Sang Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina School of Mechanical Engineering and Automation Dalian Polytechnic UniversityDalian 116034LiaoningChina

Spring steel is an indispensable basic part manufacturing material in mechanical equipment,which is widely used in transportation tools such as automobiles,railways,construction machinery and other *** effects of rare earth(RE)on inclusions,microstructure,carbides and impact toughness of 50CrV spring steel were studied by means of optical microscope,scanning electron microscope,transmission electron microscope and impact *** results show that the addition of rare earth can modify the main MnS and Al_(2)O_(3) inclusions in steel to form spherical or near-spherical rare earth inclusions,and the size of inclusions is significantly *** the quenched structure,the size of martensite slab becomes smaller and the structure is *** tempering,the carbide changes from sheet to ellipse,which makes it easier for spring steel to form stress concentration cracks under *** becomes finer and more dispersed,which leads to better pinning of grain boundaries and smaller grain *** impact toughness of 50CrV-RE spring steel increased from 21 to 41 J by 95%due to the improvement of inclusions,microstructure and carbides by rare *** is possible to improve the strength and toughness of spring steel for the improvement of railway running speed and the development of vehicle lightweight in China.

关键词： Rare earth-Spring steel Inclusion Microstructure Impact toughness

Dynamic access task scheduling of LEO constellation based on space-based distributed computing

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Journal of Systems Engineering and Electronics 2024年第4期35卷 842-854页

作者： liu Wei JIN Yifeng ZHANG lei GAO Zihe TAO Ying Institute of Telecommunication and Navigation Satellites China Academy of Space TechnologyBeijing 100094China Innovation Center of Satellite Communication System China National Space AdministrationBeijing 100094China

A dynamic multi-beam resource allocation algorithm for large low Earth orbit(LEO)constellation based on on-board distributed computing is proposed in this *** allocation is a combinatorial optimization process under a series of complex constraints,which is important for enhancing the matching between resources and requirements.A complex algorithm is not available because that the LEO on-board resources is *** proposed genetic algorithm(GA)based on two-dimen-sional individual model and uncorrelated single paternal inheri-tance method is designed to support distributed computation to enhance the feasibility of on-board application.A distributed system composed of eight embedded devices is built to verify the algorithm.A typical scenario is built in the system to evalu-ate the resource allocation process,algorithm mathematical model,trigger strategy,and distributed computation *** to the simulation and measurement results,the proposed algorithm can provide an allocation result for more than 1500 tasks in 14 s and the success rate is more than 91%in a typical *** response time is decreased by 40%com-pared with the conditional GA.

关键词： beam resource allocation distributed computing low Earth obbit(LEO)constellation spacecraft access task scheduling

A Deep Learning Approach for Forecasting Thunderstorm Gusts in the beijing–Tianjin–Hebei Region

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Advances in Atmospheric Sciences 2024年第7期41卷 1342-1363页

作者： Yunqing liu Lu YANG Mingxuan CHEN Linye SONG lei HAN Jingfeng XU Faculty of Information Science and Engineering Ocean University of ChinaQingdao 266100China Institute of Urban Meteorology China Meteorological AdministrationBeijing 100089China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China

Thunderstorm gusts are a common form of severe convective weather in the warm season in North China,and it is of great importance to correctly forecast *** present,the forecasting of thunderstorm gusts is mainly based on traditional subjective methods,which fails to achieve high-resolution and high-frequency gridded forecasts based on multiple observation *** this paper,we propose a deep learning method called Thunderstorm Gusts TransU-net(TGTransUnet)to forecast thunderstorm gusts in North China based on multi-source gridded product data from the Institute of Urban Meteorology(IUM)with a lead time of 1 to 6 *** determine the specific range of thunderstorm gusts,we combine three meteorological variables:radar reflectivity factor,lightning location,and 1-h maximum instantaneous wind speed from automatic weather stations(AWSs),and obtain a reasonable ground truth of thunderstorm ***,we transform the forecasting problem into an image-to-image problem in deep learning under the TG-TransUnet architecture,which is based on convolutional neural networks and a *** analysis and forecast data of the enriched multi-source gridded comprehensive forecasting system for the period 2021–23 are then used as training,validation,and testing ***,the performance of TG-TransUnet is compared with other *** results show that TG-TransUnet has the best prediction results at 1–6 *** IUM is currently using this model to support the forecasting of thunderstorm gusts in North China.

关键词： thunderstorm gusts deep learning weather forecasting convolutional neural network transformer