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Effect of low-speed waterjet pressure on the rock-breaking performance of unsubmerged cavitating abrasive waterjet

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Petroleum Science 2024年第4期21卷 2638-2649页

作者： Chen-Xing fan Deng Li Yong kang Hai-Tao Zhang Hubei Key Laboratory of Waterjet Theory and New Technology Wuhan University School of Power and Mechanical Engineering Wuhan University

Unsubmerged cavitating abrasive waterjet(UCAWJ) has been shown to artificially create a submerged environment that produces shear cavitation, which effectively enhances rock-breaking performance. The shear cavitation generation and collapse intensity depend on the pressure difference between the intermediate high-speed abrasive waterjet and the coaxial low-speed waterjet. However, the effect of the pressure of the coaxial low-speed waterjet is pending. For this purpose, the effect of low-speed waterjet pressure on rock-breaking performance at different standoff distances was experimentally investigated,and the effects of erosion time and ruby nozzle diameter on erosion performance were discussed. Finally,the micromorphology of the sandstone was observed at different locations. The results show that increased erosion time and ruby nozzle diameter can significantly improve the rock-breaking performance. At different standoff distances, the mass loss increases first and then decreases with the increase of low-speed waterjet pressure, the maximum mass loss is 10.4 g at a low-speed waterjet pressure of0.09 MPa. The surface morphology of cavitation erosion was measured using a 3D profiler, the increase in both erosion depth and surface roughness indicated a significant increase in the intensity of the shear cavitation collapse. At a low-speed waterjet pressure of 0.18 MPa, the cavitation erosion surface depth can reach 600 μm with a roughness of 127 μm.

关键词： Rock-breaking Coaxial low-speed waterjet pressure Abrasive waterjet Cavitation Unsubmerged environment

Transition from grain boundary migration to grain boundary sliding in magnesium bicrystals

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Acta Mechanica Sinica 2024年第8期40卷 17-31页

作者： Zheyuan Xing Haidong fan Chuanlong Xu Guozheng kang School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu610031China Department of Mechanics Sichuan UniversityChengdu610065China

In polycrystalline magnesium(Mg)and Mg alloys,as the grain size decreases,the grain boundary(GB)mediated plasticity including GB sliding and GB migration becomes the dominant deformation *** this study,the motion of[1100]symmetric tilt GBs in Mg bicrystals is investigated using molecular dynamics(MD)*** effects of GB misorientation angle and temperature are *** low/room temperatures and varied GB misorientation angles in the range ofθ≥58.36°,the GB migration occurs via the shear coupling with the invariant plane of{0001};At 35.80°<θ<58.36°,both the GB migration and GB sliding happen and the invariant plane changes from{0001}plane to[1122]plane;At 26.54°≤θ≤35.80°,the GB migrates with the invariant plane of[1122];Finally,atθ<26.54°,the GB sliding becomes the main deformation *** 700 K,the GB sliding occurs at the misorientation angles in the range ofθ<58.36θ;while the GB migration occurs at the misorientation angles ofθ≥58.36°.By comparing the energy barriers of GB migration and GB sliding,it yields that the deformation mode with a low energy barrier always happens,which leads to the transition of deformation modes and agrees well with the MD simulation results.

关键词： Molecular dynamics simulations Magnesium Grain boundary migration Grain boundary sliding Temperature

Comparative assessment of liver tissue:from microstructural and mesoscale vascular architecture to macroscopic mechanics

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Acta Mechanica Sinica 2024年第7期40卷 195-205页

作者： Wei kang Kaixin Sun Lizhen Wang Yubo fan Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijing 100083China School of Engineering Medicine Beihang UniversityBeijing 100083China

Accurately characterizing the liver's mechanical properties is of paramount importance for disease diagnosis,treatment,surgical prosthetic modeling,and impact injury ***,due to its inherent biological soft tissue nature,the characterization of mechanical behavior varies across testing methods and sample *** this study,we employed transmission electron microscope and Micro CT to observe the morphology of the marginal and center of rat livers and conducted macroscopic mechanical tests to characterize their elasticity and *** results revealed that the central region displayed higher metabolic levels,elongated mitochondria,and an abundance of rough endoplasmic reticulum at the *** the mesoscale,larger diameter portal veins were mainly distributed in the central region,while smaller diameter arteries were predominantly located at the *** the macroscale,under a strain rate of 0.0167 s^(-1),no significant differences were observed in the elastic properties between the two ***,as the strain rate increased up to 0.167 s^(-1),the central region displayed higher porosity,resulting in reduced liquid loss,increased hardness,and higher viscosity compared to the ***,the liver demonstrated overall heterogeneity,with isotropic models suitable for the peripheral region,while more intricate models may be required to capture the complexity of the central region with its intricate vasculature.

关键词： Liver Mechanical properties Micro and macro tests

Non-adiabatic holonomic quantum operations in continuous variable systems

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 12-19页

作者： Hao-Long Zhang Yi-Hao kang fan Wu Zhen-Biao Yang Shi-Biao Zheng Fujian Key Laboratory of Quantum Information and Quantum Optics College of Physics and Information EngineeringFuzhou UniversityFuzhou 350116China

Quantum operations by utilizing the underlying geometric phases produced in physical systems are favoured due to their potential *** a system in a non-degenerate eigenstate undergoes an adiabatically cyclic evolution dominated by its Hamiltonian,it will get a geometric phase,referred to as the Berry *** a non-adiabatically cyclic evolution produces an Aharonov-Anandan geometric *** two types of Abelian geometric phases are extended to the non-Abelian cases,where the phase factors become matrix-valued and the transformations associated with different loops are *** and non-Abelian(holonomic)operations are prevalent in discrete variable systems,whose limited(say,two)energy levels,form the *** their developments in continuous systems have also been investigated,mainly due to that,bosonic modes(in,such as,cat states)with large Hilbert spaces,provide potential advantages in fault-tolerant quantum *** we propose a feasible scheme to realize non-adiabatic holonomic quantum logic operations in continuous variable systems with cat *** construct arbitrary single-qubit(two-qubit)gates with the combination of single-and two-photon drivings applied to a Kerr Parametric Oscillator(KPO)(the coupled KPOs).Our scheme relaxes the requirements of the previously proposed quantum geometric operation strategies in continuous variable systems,providing an effective way for quantum control.

关键词： cat qubit continuous variable systems non-Abelian

A Novel Multiple DBC-staked units Package to Parallel More Chips for SiC Power Module

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CES Transactions on Electrical Machines and Systems 2024年第1期8卷 72-79页

作者： Xiaoshuang Hui Puqi Ning Tao fan Yuhui kang Kai Wang Yunhui Mei Guangyin Lei Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100049China the school of Electronic Electrical and Communication EngineeringUniversity of Chinese Academy of SciencesBeijing 100190China IEEE the School of Electrical Engineering Tiangong UniversityTianjin 300387China the Academy for Engineering and Technology Fudan UniversityShanghai 200433China

Silicon carbide(SiC) power modules play an essential role in the electric vehicle drive system. To improve their performance, reduce their size, and increase production efficiency, this paper proposes a multiple staked direct bonded copper(DBC) unit based power module packaging method to parallel more chips. This method utilizes mutual inductance cancellation effect to reduce parasitic inductance. Because the conduction area in the new package is doubled, the overall area of power module can be reduced. Entire power module is divided into smaller units to enhance manufacture yield, and improve design freedom. This paper provides a detailed design, analysis and fabrication procedure for the proposed package structure. Additionally, this paper offers several feasible solutions for the connection between power terminals and DBC untis. With the structure, 18dies were paralleled for each phase-leg in a econodual size power module. Both simulation and double pulse test results demonstrate that, compared to conventional layouts, the proposed package method has 74.8% smaller parasitic inductance and 34.9% lower footprint.

关键词： Silicon carbide Electric vehicle Power modules Package

Lignin‐derived carbon with pyridine N‐B doping and a nanosandwich structure for high and stable lithium storage

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Carbon Energy 2024年第8期6卷 232-247页

作者： Dichao Wu Jiayuan Li Yuying Zhao Ao Wang Gaoyue Zhang Jianchun Jiang Mengmeng fan kang Sun Key Lab of Biomass Energy and Material Jiangsu ProvinceNational Engineering Lab for Biomass Chemical UtilizationKey and Open Lab on Forest Chemical EngineeringSFAInstitute of Chemical Industry of Forest ProductsChinese Academy of ForestryNanjingChina Jiangsu Co‐Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjingChina School of Energy and Environment Southeast UniversityNanjingChina Department of Chemistry Tsinghua UniversityBeijingChina Fujian Provincial Key Laboratory of Biomass Low‐Carbon Conversion Academy of Advanced Carbon Conversion TechnologyHuaqiao UniversityXiamenChina Chinese Academy of Sciences Xinjiang Lihua Institute of Technology UrumqiChina

Biomass‐derived carbon is a promising electrode material in energy storage ***,how to improve its low capacity and stability,and slow diffusion kinetics during lithium storage remains a *** this research,we propose a“self‐assembly‐template”method to prepare B,N codoped porous carbon(BN‐C)with a nanosandwich structure and abundant pyridinic N‐B *** nanosandwich structure can increase powder density and cycle stability by constructing a stable solid electrolyte interphase film,shortening the Li^(+)diffusion pathway,and accommodating volume expansion during repeated charging/*** abundant pyridinic N‐B species can simultaneously promote the adsorption/desorption of Li^(+)/PF_(6)^(−)and reduce the diffusion *** BN‐C electrode showed a high lithium‐ion storage capacity of above 1140 mAh g^(−1)at 0.05 A g^(−1)and superior stability(96.5%retained after 2000 cycles).Moreover,owing to the synergistic effect of the nanosandwich structure and pyridinic N‐B species,the assembled symmetrical BN‐C//BN‐C full cell shows a high energy density of 234.7Wh kg^(−1),high power density of 39.38 kW kg−1,and excellent cycling stability,superior to most of the other cells reported in the *** the density functional theory simulation demonstrated,pyridinic N‐B shows enhanced adsorption activity for Li^(+)and PF_(6)^(−),which promotes an increase in the capacity of the anode and cathode,***,the relatively lower diffusion barrier of pyridinic N‐B promotes Li^(+)migration,resulting in good rate ***,this study provides a new approach for the synergistic modulation of a nanostructure and an active site simultaneously to fabricate the carbon electrode material in energy storage devices.

关键词： high cycling stability high energy density lithium‐ion batteries pyridinic N‐B species sandwich structure carbon nanosheet

Assembling ionic liquid into porous molecular filler of mixed matrix membrane to trigger high gas permeability,selectivity,and stability for CO_(2)/CH_(4) separation

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Nano Research 2024年第5期17卷 4535-4543页

作者： Liting Yu Liqin Hao Yang Feng Jia Pang Mengwei Guo Liangjun Li Weidong fan Lili fan Rongming Wang Zixi kang Daofeng Sun School of Materials Science and Engineering State Key Laboratory of Heavy Oil ProcessingChina University of Petroleum(East China)Qingdao 266580China College of Chemistry Nankai UniversityTianjin 300071China College of Chemistry and Chemical Engineering China University of Petroleum(East China)Qingdao 266580China College of New Energy China University of Petroleum(East China)Qingdao 266580China

As an emerging zero-dimensional nano crystalline porous material,porous organic cages(POCs)with soluble properties in organic solvents,are promising candidates as molecular fillers in mixed matrix membranes(MMMs).The pore structure of POCs should be adjusted to trigger efficient gas separation performance,and the interaction between filler and matrix should be *** this work,ionic liquid(IL)was introduced into the molecular fillers of CC3,to construct the IL@CC3/PIM-1 membrane to effectively separate CO_(2) from CH_(4).The advantages of doping IL include:(1)narrowing the cavity size of POCs from 4.4 to 3.9Åto enhance the diffusion selectivity,(2)strengthening the CO_(2) solubility to heighten the gas permeability,and(3)improving the compatibility between filler and matrix to upgrade membrane *** the optimization of the membrane composite,the IL@CC3/PIM-1-10%membrane possesses the CO_(2) permeability of 7868 Barrer and the CO_(2)/CH_(4) selectivity of 73.4,which compared to the CC3/PIM-1-10%membrane,improved by 15.9%and 106.2%,***,the membrane has maintained a stable separation performance at varied temperatures and pressures during the long-term *** proposed method offers an efficient way to improve the performance of POCs-based MMMs in gas separation.

关键词： porous organic cage mixed matrix membrane ionic liquid gas separation

Renewable conversion of coal gangue to 13-X molecular sieve for Cd^(2+)-containing wastewater adsorption performance

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Rare Metals 2024年第2期43卷 702-710页

作者： Le kang Si-fan Liu Da-Wei Yi Kai Wang Hui-Ling Du Hao-Qi Huang Peng Chen College of Materials Science and Engineering Xi’an University of Science and TechnologyXi’an710054China School of Electrical Engineering Weihai Innovation Research InstituteQingdao UniversityQingdao266000China School of Metallurgy Northeastern UniversityShenyang110819China School of Materials and Chemical Engineering Tongren UniversityTongren554300China

Using coal gangue(CG)as raw material,a new type of all solid-waste-based 13-X molecular sieve material was controllably prepared by alkali fusion-hydrothermal *** synthetic molecular sieve was used as a solid adsorbent to treat Cd^(2+)-containing wastewater,and its adsorption behavior on Cd^(2+)in aqueous solution was studied and *** microstructure and morphology of the molecular sieve were investigated by X-ray diffraction(XRD),field emission scanning electron microscopy(FESEM)and specific surface area *** results show that the synthesized 13-X molecular sieve has higher Brunauer–Emmett–Teller(BET)specific surface area with higher crystallinity and higher adsorption capacity for the heavy metal Cd^(2+).The adsorption process of Cd^(2+)by molecular sieve conforms to the Langmuir isotherm adsorption equation and Lagergren pseudo-second-order rate *** with thermodynamic calculation,it can be concluded that the adsorption process is physically monolayer,spontaneous and *** this study,a low-cost and naturally available synthesis method of 13-X molecular sieve is *** with its adsorption mechanism for Cd^(2+),it provides a feasible and general method for removing heavy metal ions from coal gangue and also provides a new way for the utilization of coal gangue with high added value.

关键词： Coal gangue Hydrothermal synthesis 13-X molecular sieve Adsorption Wastewater containing Cd^(2+)

The Short-Term Prediction ofWind Power Based on the Convolutional Graph Attention Deep Neural Network

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Energy Engineering 2024年第2期121卷 359-376页

作者： fan Xiao Xiong Ping Yeyang Li Yusen Xu Yiqun kang Dan Liu Nianming Zhang State Grid Hubei Electric Power Research Institute Wuhan430077China College of Energy and Electrical Engineering Hohai UniversityNanjing210098China

The fluctuation of wind power affects the operating safety and power consumption of the electric power grid and restricts the grid connection of wind power on a large ***,wind power forecasting plays a key role in improving the safety and economic benefits of the power *** paper proposes a wind power predicting method based on a convolutional graph attention deep neural network with multi-wind farm *** on the graph attention network and attention mechanism,the method extracts spatial-temporal characteristics from the data of multiple wind ***,combined with a deep neural network,a convolutional graph attention deep neural network model is ***,the model is trained with the quantile regression loss function to achieve the wind power deterministic and probabilistic prediction based on multi-wind farm spatial-temporal data.A wind power dataset in the *** taken as an example to demonstrate the efficacy of the proposed *** with the selected baseline methods,the proposed model achieves the best prediction *** point prediction errors(i.e.,root mean square error(RMSE)and normalized mean absolute percentage error(NMAPE))are 0.304 MW and 1.177%,*** the comprehensive performance of probabilistic prediction(i.e.,con-tinuously ranked probability score(CRPS))is ***,the significance of multi-wind farm data and spatial-temporal feature extraction module is self-evident.

关键词： Format wind power prediction deep neural network graph attention network attention mechanism quantile regression