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A novel domain decomposition-based model for efficient dynamic predictions of large composite machine tools

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Science China(Technological Sciences) 2024年第6期67卷 1765-1782页

作者： YU YangBo JI Yu Lei CHEN YanRen XU Kun bi QingZhen State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China

We propose a large combined moving component composed of carbon fiber reinforced polymer(CFRP)laminates for making lightweight machine tools with high dynamic *** accurate dynamic prediction of composite machine tools is essential for the new generation machine *** paper aims to address two challenges in numerical dynamic modeling and the design of composite machine tools to enhance development efficiency.(1)Anisotropic composite laminates,which form the composite machine tool,exhibit coupling in various *** propose the generalized continuity condition of the boundary to tackle this dynamic modeling challenge.(2)Composite machine tools feature numerous composite-metal coupled *** mechanical model correction of isotropic metals is performed to address their *** take the example of a five-axis gantry machine tool with composite moving parts,establish a dynamic model for efficient prediction,and verify it through simulation and *** proposed method yields remarkable results,with an average relative error of only 3.85%in modal frequency prediction and a staggering 99.7%reduction in solution time compared to finite element *** further discuss the dynamic performance of the machine tool under varied stacking angles and layer numbers of the composite machine *** propose general design criteria for composite machine tools to consider the modal frequency and manufacturing cost of machine tools.

关键词： machine tool dynamics carbon fiber reinforced polymer composite laminates

Chronic sleep deprivation induces alterations in DNA and RNA modifications by liquid chromatography-mass spectrometry analysis

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Chinese Chemical Letters 2024年第8期35卷 413-417页

作者： tian Feng Yun-Ling Gao Di Hu Ke-Yu Yuan Shu-Yi Gu Yao-Hua Gu Si-Yu Yu Jun Xiong Yu-Qi Feng Jie Wang bi-Feng Yuan School of Public Health Research Center of Public HealthRenmin Hospital of Wuhan UniversityWuhan UniversityWuhan 430071China Department of Radiation and Medical Oncology Zhongnan Hospital of Wuhan UniversityWuhan UniversityWuhan 430071China Key Laboratory of Magnetic Resonance in biological Systems State Key Laboratory of Magnetic Resonance and Atomic and Molecular PhysicsNational Center for Magnetic Resonance in WuhanWuhan Institute of Physics and MathematicsInnovation Academy for Precision Measurement Science and TechnologyChinese Academy of Sciences-Wuhan National Laboratory for OptoelectronicsWuhan 430071China University of Chinese Academy of Sciences Beijing 101408China Institute of Neuroscience and Brain Diseases Xiangyang Central HospitalAffiliated Hospital of Hubei University of Arts and ScienceXiangyang 441000China Phase I Clinical Trial Laboratory Zhongnan Hospital of Wuhan UniversityWuhan 430071China

Sleep deprivation(SD)is a widespread issue that disrupts the lives of millions of *** effects ini-tiate as changes within neurons,specifically at the DNA and RNA level,leading to disruptions in neuronal plasticity and the dysregulation of various cognitive functions,such as learning and *** acid epigenetic modifications that could regulate gene expression have been reported to play crucial roles in this ***,there is a lack of comprehensive research on the correlation of SD with nucleic acid epigenetic *** the current study,we aimed to systematically investigate the landscape of modifications in DNA as well as in small RNA molecules across multiple tissues,including the heart,liver,kidney,lung,hippocampus,and spleen,in response to chronic sleep deprivation(CSD).Using liquid chromatography-tandem mass spectrometry(LC-MS/MS)analysis,we characterized the dynamic changes in DNA and RNA modification profiles in different tissues of mice under CSD ***,we ob-served a significant decrease in the level of 5-methylcytosine(5mC)and a significant increase in the level of 5-hydroxymethylcytosine(5hmC)in the kidney in CSD *** RNA modifications,we observed an overall increased trend for most of these significantly changed modifications across six tis-sues in CSD *** study sheds light on the significance of DNA and RNA modifications as crucial epigenetic markers in the context of CSD-induced stress.

关键词： Sleep deprivation Epigenetics Mass spectrometry DNA modification RNA modification Small RNA

Application of CFD and FEA Coupling to Predict Structural Dynamic Responses of A Trimaran in Uni-and bi-Directional Waves

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China Ocean Engineering 2024年第1期38卷 81-92页

作者： LIAO Xi-yu xia Jin-song CHEN Zhan-yang TANG Qin ZHAO Nan ZHAO Wei-dong GUI Hong-bin Marine Design&Research Institute of China Shanghai 200011China Ship Structure Division China Ship Scientific Research CenterWuxi 214082China College of Ocean Engineering Harbin Institute of TechnologyWeihaiWeihai 264209China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China School of Foreign Studies Jiangnan UniversityWuxi 214122China

To predict the wave loads of a flexible trimaran in different wave fields,a one-way interaction numerical simulation method is proposed by integrating the fluid solver(Star-CCM+)and structural solver(Abaqus).Differing from the existing coupled CFD-FEA method for monohull ships in head waves,the presented method equates the mass and stiffness of the whole ship to the hull shell so that any transverse and longitudinal section stress of the hull in oblique waves can be ***,verification study and sensitivity analysis are carried out by comparing the trimaran motions using different mesh sizes and time step *** on the wave elevation of uni-and bi-directional waves is also carried *** a comprehensive analysis on the structural responses of the trimaran in different uni-directional regular wave and bi-directional cross sea conditions is carried out,***,the differences in structural response characteristics of trimaran in different wave fields are *** results show that the present method can reduce the computational burden of the two-way fluid-structure interaction simulations.

关键词： CFD-FEA fluid-structure coupling structural responses trimaran bi-directional cross sea

Numerical simulation of aircraft arresting process with an efficient full-scale rigid-flexible coupling dynamic model

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Chinese Journal of Aeronautics 2024年第5期37卷 586-602页

作者： Haoyuan SHAO Daochun LI Zi KAN Lanxi bi Zhuoer YAO Jinwu xiaNG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China tianmushan Laboratory Hangzhou 310023China

The arresting process of carrier-based aircraft is widely recognized as a challenging task,characterized by the highest accident rate among all carrier-based aircraft *** simulation plays a crucial role in assessing the intricate responses of the arresting process,favoring the design of carrier-based *** efficient and accurate rigid-flexible coupling model for analyzing the dynamic response of the arresting process is *** combining the dynamic characteristics of airframe,landing gear,arresting hook and arresting gear system,the rigid-flexible coupling dynamic model is established to reflect the relative motion of the coupling parts and arresting *** dynamic model is verified through simulations of landing gear landing drops and by comparing the arresting simulation results with corresponding data in the US military ***,simulations of the arresting process under different off-center distance and aircraft yaw angle are conducted to obtain the dynamic response of the aircraft during the arresting *** result indicates that the rigid-flexible coupling dynamic model proposed is effective for analyzing the arresting dynamics response of carrier-based *** axial force of the arresting cable on both sides of the hook engagement point,pitch and yaw angle of aircraft are inconsistent under yaw and off-center *** analysis method and obtained results provide valuable references for assessing the dynamic responses of carrier-based aircraft during arresting process and offer valuable in-sights in the design of carrier-based aircraft.

关键词： Carrier-based aircraft Deck landing Rigid-flexible coupling dynamic model Finite element method Dynamic analysis

Responses of soil stoichiometry and soil enzyme activities in the different distance around opencast coal mine of the Hulun Buir Grassland of China

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International Journal of Coal Science & Technology 2024年第1期11卷 221-231页

作者： Yinli bi Nan Guo Yanxu Zhang xianglei Li Ziheng Song State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources China University of Mining and Technology(Beijing)Beijing100083China Institute of Ecological Environment Restoration in Mine Areas of West China Xi’an University of Science and TechnologyXi’an710054China

The objectives of this study were to explore the changes in soil stoichiometry and enzyme activities at different distances from an opencast coal mine in the Hulun Buir Grassland of China. Four transects were established on north and east sides of the opencast coal mining area, and samples were collected at 50 m, 550 m, and 1550 m from the pit on each transect. Control samples were collected from a grassland station 8 km from the opencast coal mining area that was not disturbed by mining. Four replicate soil samples were collected at each point on the four transects. Soil physicochemical properties and enzyme activities were determined, and correlations between soil properties and stoichiometric ratios and enzyme activities were explored using redundancy analysis. The increase in distance from mining did not significantly affect soil properties, although soil urease activity was significantly lower than that of the control area. Soil properties 1550 m from the mine pit were similar to those at the grassland control. In addition, soil total nitrogen had the greatest effect on soil stoichiometry, and soil total potassium had the greatest effect on soil enzyme activities. Coal dust from opencast mining might be the main factor affecting soil stoichiometry and enzyme activities. The results of this study provide direction for the next step in studying the influence of mining areas on soil properties and processes.

关键词： Opencast coal mine Soil stoichiometry Soil enzyme activities Distance Grassland

Influence of rare earth oxides on microstructure and mechanical properties of nickel-based superalloys fabricated by high energy beam processing:A review

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Journal of Rare Earths 2024年第9期42卷 1629-1645,I0001页

作者： Lianjie bi Hua Yan Peilei Zhang Haichuan Shi Zhiyuan Li Ruidi Li School of Materials Science and Engineering Shanghai University of Engineering ScienceShanghai201620China College of Agricultural Science and Engineering Hohai UniversityNanjing211100China Department of Mechanics and Maritime Science Chalmers University of TechnologyGothenburSE41296Sweden State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083China

In this paper,the effects of rare earth oxides on the micro structure and mechanical properties of nickelbased superalloys prepared by high-energy beam processing technology were critically *** focus is on the optimal amount of rare earth oxides that can produce ideal *** attention was paid to their main strengthening mechanisms,including solid solution strengthening mainly in the form of solid solution dissolved in the nickel-based alloy and improving the microstructure of the alloy by grain refinement or fine grain strengthening produced by homogenizing the distribution phase.Y_(2)O_(3),La_(2)O_(3) and CeO_(2) rare earth oxides can also improve the fluidity of the alloy molten pool and reduce the segregation of alloying *** advantages can significantly improve the mechanical properties of the ***,this paper outlines the future research directions of rare earth oxides,aiming to expand their application potential.

关键词： Rare earths High energy beam Nickel-based superalloys Microstructure Mechanical properties

Structural Characteristics and Influencing Factors of Carbon Emission Spatial Association Network:A Case Study of Yangtze River Delta City Cluster,China

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Chinese Geographical Science 2024年第4期34卷 689-705页

作者： bi Xi SUN Renjin HU Dongou SHI Hongling ZHANG Han School of Economics and Management China University of Petroleum(Beijing)Beijing 102249China China Petroleum Planning&Engineering Institute Beijing 100083China

City cluster is an effective platform for encouraging regionally coordinated *** reduction of carbon emissions within city cluster via the spatial association network between cities can help coordinate the regional carbon emission management,realize sustainable development,and assist China in achieving the carbon peaking and carbon neutrality *** paper applies the improved gravity model and social network analysis(SNA)to the study of spatial correlation of carbon emissions in city clusters and analyzes the structural characteristics of the spatial correlation network of carbon emissions in the Yangtze River Delta(YRD)city cluster in China and its influencing *** results demonstrate that:1)the spatial association of carbon emissions in the YRD city cluster exhibits a typical and complex multi-threaded network *** network association number and density show an upward trend,indicating closer spatial association between cities,but their values remain generally ***,the network hierarchy and network efficiency show a downward trend but remain high.2)The spatial association network of carbon emissions in the YRD city cluster shows an obvious‘core-edge’distribution *** network is centered around Shanghai,Suzhou and Wuxi,all of which play the role of‘bridges’,while cities such as Zhoushan,Ma'anshan,Tongling and other cities characterized by the remote location,single transportation mode or lower economic level are positioned at the edge of the network.3)Geographic proximity,varying levels of economic development,different industrial structures,degrees of urbanization,levels of technological innovation,energy intensities and environmental regulation are important influencing factors on the spatial association of within the YRD city ***,policy implications are provided from four aspects:government macro-control and market mechanism guidance,structural characteristics of the‘core-edge’network,reconfigura

关键词： carbon emission spatial association network social network analysis(SNA) quadratic assignment procedure(QAP)model Yangtze River Delta city cluster China

A modified 3D mean strain energy density criterion for predicting shale mixed-mode Ⅰ/Ⅲ fracture toughness

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2411-2428页

作者： Kun Zheng Chaolin Wang Yu Zhao Jing bi Haifeng Liu College of Civil Engineering Guizhou UniversityGuiyang550025China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The fracture toughness of rocks is a critical fracturing parameter in geo-energy exploitation playing a significant role in fracture mechanics and hydraulic *** edge-notched disk bending(ENDB)specimens are employed to measure the entire range of mixed-modeⅠ/Ⅲfracture toughness of Longmaxi *** theoretically interpret the fracture mechanisms,this research first introduces the detailed derivations of three established fracture *** distinguishing the volumetric and distortional strain energy densities,an improved three-dimensional mean strain energy density(MSED)criterion is *** the critical volumetric to distortional MSED ratio decreases,the transition from tensiondominated fracture to shear-dominated fracture is *** results indicate that both peak load and applied energy increase significantly with the transition from pure mode I(i.e.,tension)to pure modeⅢ(i.e.,torsion or tearing)since mode-Ⅲcracking happens in a twisted manner and mode-Ⅰcracking occurs in a coplanar *** macroscopic fracture signatures are consistent with those of triaxial hydraulic *** average ratio of pure mode-Ⅲfracture toughness to pure mode-Ⅰfracture toughness is 0.68,indicating that the obtained mode-Ⅲfracture resistance for a tensionbased loading system is apparent rather than *** to the three mainstream fracture criteria,the present fracture criterion exhibits greater competitiveness and can successfully evaluate and predict mixed-modeⅠ/Ⅲfracture toughness of distinct materials and loading methods.

关键词： Longmaxi shale Hydraulic fracturing Fracture mechanisms Fracture criteria Mixed-modeⅠ/Ⅲfracture toughness Edge-notched disk bending

Formation mechanism of Fe-based amorphous powders produced by spark erosion

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Journal of Materials Science & Technology 2024年第3期170卷 33-46页

作者： Chekai Liu Ran Li Jiazi bi Ding Ma xiaobin Liu Tao Zhang School of Materials Science and Engineering Key Laboratory of Aerospace Materials and Performance(Ministry of Education)Beihang UniversityBeijing 100191China

Spark erosion is a convenient,flexible,and low-cost method to quickly produce fine powders of metals,alloys,and semiconductors in size ranging from nearly a hundred micrometers to submicrometer by repetitive spark *** to the complexity of the powder-forming journey,normally accompanied by high temperature,high pressure,decomposition,diffusion and rapid quenching caused by discharge plasma,the mechanisms of powder formation and possible contaminant infiltration are still controversial,posing a significant challenge to control particle size and chemical composition of the powder produced by this *** this study,Fe-based amorphous powders in different particle-size distributions with high sphericity were fabricated by spark erosion under different discharge-energy *** max-imum particle size of the resultant powders can be correlated with discharge parameters,crater depth,and crater radius,respectively.A multi-ring-breakup model is proposed to reveal the particle-size distribution of the powder formed from the electrode melt under a single-pulse ***,a dielectric-element infiltration model is provided to quantitatively evaluate the infiltration mass ratio of the contaminant elements,stemming from the decomposed products of dielectric liquid,in the resultant powder with different particle *** models verified through the experimental data are significant for the development of high-performance fine Fe-based amorphous powder with controlled particle size and chemical composition.

关键词： Amorphous alloy Particle Spark erosion Infiltration Modeling