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Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang shen Ying-Shun Zhu Fu-San Chen China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China Institute of High Energy Physics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Currently,three types of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analytical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analytical expressions of the field harmonics and gradient are fully resolved and depend only on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry parameters with field harmonics on the order of 10^(-4).Finally,considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analyzed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design

A Coordinate-Free Approach to the Design of Generalized Griffis-Duffy Platforms

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 95-103页

作者： Chengwei shen Xu Pei Lubin Hang Jingjun Yu College of Optical Mechanical and Electrical EngineeringZhejiang A&F UniversityHangzhou 311300China School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Mechanical and Automotive Engineering Shanghai University of Engineering ScienceShanghai 201620China

Architectural singularity belongs to the Type II singularity,in which a parallel manipulator(PM)gains one or more degrees of freedom and becomes *** remaining permanently in a singularity are beneficial for linearto-rotary motion ***-Duffy(GD)platform is a mobile structure admitting a Bricard *** this paper,we present a coordinate-free approach to the design of generalized GD platforms,which consists in determining the shape and attachment of both the moving platform and the fixed *** generalized GD platform is treated as a combination of six coaxial single-loop mechanisms under the same *** to the inversion,hidden in the geometric structure of these single-loop mechanisms,the mapping from a line to a circle establishes the geometric transformation between the fixed base and the moving platform based on the center of inversion,and describes the shape and attachment of the generalized GD ***,the center of inversion not only identifies the location of rotation axis,but also affects the shape of the platform mechanism.A graphical construction of generalized GD platforms using inversion,proposed in the paper,provides geometrically feasible solutions of the manipulator design for the requirement of the location of rotation axis.

关键词： Generalized Griffis-Duffy platforms Self-motion Inversion Coordinate-free determination Manipulator design

Exploring the potential of olivine-containing copper-nickel slag for carbon dioxide mineralization in cementitious materials

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 562-573页

作者： Qianqian Wang Zequn Yao Lijie Guo Xiaodong shen College of Materials Science and Engineering Nanjing Tech UniversityNanjing 211816China State Key Laboratory of Materials-Oriented Chemical Engineering Nanjing 211816China BGRIMM Technology Group Beijing 100160China

Water-quenched copper-nickel metallurgical slag enriched with olivine minerals exhibits promising potential for the production of CO_(2)-mineralized cementitious *** this work,copper-nickel slag-based cementitious material(CNCM)was synthesized by using different chemical activation methods to enhance its hydration reactivity and CO_(2) mineralization *** water curing ages and carbonation conditions were explored related to their carbonation and mechanical properties ***,thermogravimetry differential scanning calorimetry and X-ray diffraction methods were applied to evaluate the CO_(2) adsorption amount and carbonation products of *** development of carbonated CNCM blocks was examined by backscattered electron imaging(BSE)with energy-dispersive X-ray *** showed that among the studied samples,the CNCM sample that was subjected to water curing for 3 d exhibited the highest CO_(2) sequestration amount of 8.51wt%at 80℃and 72 h while presenting the compressive strength of 39.07 *** result indicated that 1 t of this CNCM can sequester 85.1 kg of CO_(2) and exhibit high compressive *** the addition of citric acid did not improve strength development,it was beneficial to increase the CO_(2) diffusion and adsorption amount under the same carbonation conditions from BSE *** work provides guidance for synthesizing CO_(2)-mineralized cementitious materials using large amounts of metallurgical slags containing olivine minerals.

关键词： copper-nickel slag fayalite CO_(2)sequestration cementitious material admixtures carbonation conditions

Study on thermal decomposition kinetics of azobenzene-4,4′-dicarboxylic acid by using compensation parameter method and nonlinear fitting evaluation

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Chinese Journal of Chemical Engineering 2024年第6期70卷 269-279页

作者： Shuyi shen Song Guo Sining Chen Jinhua Zhao Nanjing University of Science&Technology Nanjing 210094China China Academy of Safety Science and Technology Beijing 100012China

Recently,azobenzene-4,4'-dicarboxylic acid(ADCA)has been produced gradually for use as an organic synthesis or pharmaceutical intermediate due to its eminent *** large quantities put into application in the future,the thermal stability of this substance during storage,transportation,and use will become quite ***,in this work,the thermal decomposition behavior,thermal decomposition kinetics,and thermal hazard of ADCA were *** were conducted by using a SENSYS evo DSC device.A combination of differential iso-conversion method,compensation parameter method,and nonlinear fitting evaluation were also used to analyze thermal kinetics and mechanism of ADCA *** results show that when conversion rate α increases,the activation energies of ADCA's first and main decomposition peaks *** amount of heat released during decomposition varies between 182.46 and 231.16 J·g^(-1).The proposed kinetic equation is based on the Avrami-Erofeev model,which is consistent with the decomposition *** the Frank-Kamenetskii model,a calculated self-accelerating decomposition temperature of 287.0℃is obtained.

关键词： Azobenzene-4,4′-dicarboxylic acid Thermal decomposition behavior Kinetic mechanism Thermal hazard evaluation Compensation parameter effect

Improving surface integrity of micro-holes in ECDM using ultrahigh-speed rotary of tool cathode and non-water-based electrolyte

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Chinese Journal of Aeronautics 2024年第5期37卷 506-519页

作者： Jiwen shen Weijing KONG Zhengyang XU Yongbin ZENG Jiangsu Key Laboratory of Precision and Micro-Manufacturing Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The surface integrity of metal micro-hole structures produced by electrochemical discharge machining is unsatisfactory owing to the insufficient reaction area and strength of electrolysis action.A novel ultrahigh-speed Rotary Electrochemical Discharge Machining(R-ECDM)using non-water-based electrolyte is proposed to improve surface integrity by changing the breakdown medium of spark discharge and increasing the reaction area and strength of electrolysis.A mathematical model was developed to establish the relationship between rotational speed and forces acting on the *** on the magnitude of forces,controlling rotational speed changed the behavior and departure radius of bubbles on the cathode ***-speed photographs validate that,in the mathematical model,the number and departure radius of bubbles on the cathode surface gradually decrease with the increase of rotational *** experimental results show that the roughness(Ra)of the micro-hole sidewall decreases from 2.54μm to 0.20μm when the rotational speed increases from 500 r/min to 40000 r/*** length loss and wear ratio of the cathode are only 9.75μm and 6.5%,***,the micro-holes array with recast-free and surface roughness of 0.20μm is fabricated,demonstrating that the proposed approach contributes to improving surface integrity of metal micro-holes.

关键词： Electrochemical discharge machining Micro-holes Recast layer Ultrahigh-speed rotary Bubbles Force analysis Non-water-based solution

Design method and experimental study of a cathode tool with an extremely high leveling ratio for electrochemical machining of blisk

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Chinese Journal of Aeronautics 2024年第4期37卷 593-608页

作者： Moqi shen Jia LIU Jingtao WANG Di ZHU College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

To obtain final parts with the desired dimensional accuracy and repeatability via electrochemical machining(ECM), the machining process must enter an ECM balanced state. However,for the ECM processing of blisk, a key component of aerospace engines, the surface of the blade blank often has an uneven allowance distribution due to the narrow passage of the cascade. It is difficult to remedy this issue in subsequent processing steps, which is necessary to ensure the dimensional accuracy and repeatability of the final blade profile. To solve this problem, electrolytic machining must be preceded by electrolytic shaping, which requires cathode tools with large leveling ratios to quickly homogenize the blank surface of the blade. In this study, to obtain a cathode tool with an extremely high leveling ratio, a design method based on the variation in the electrode gap in the non-equilibrium electrolytic state is proposed, and a dissolution model based on the nonequilibrium state is established. In this design method, the allowance on the blank to be machined is first divided into many discrete allowances with the normal direction. The initial machining clearance, feed rate, and total machining time are then calculated using classical ECM equilibrium state theory based on the maximum allowance. Meanwhile, the point coordinates of the cathode tool at maximum allowance can be determined. The non-equilibrium model can then be used to calculate the relative coordinate positions corresponding to the remaining discrete allowances. Finally, the entire cathode tool profile is designed. Simulations, fundamental experiments, and blisk unit workpiece experiments were carried out to validate the design approach. In the simulated processing of the plane workpiece, the leveling ratio of the cathode tool designed by the proposed method(0.77)was 83% higher than that of the cathode tool designed using the traditional method. The simulation results were confirmed by processing experiments. In t

关键词： Electrochemical machining(ECM) Non-equilibrium machining Large leveling ratios Cathode design Finite element simulation Blisk

Auto-parametric resonance of a continuous-beam-bridge model under two-point periodic excitation:an experimental investigation and stability analysis

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Earthquake Engineering and Engineering Vibration 2024年第2期23卷 445-454页

作者： Li Yuchun shen Chao Liu Wei Li Dong Department of Hydraulic Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The auto-parametric resonance of a continuous-beam bridge model subjected to a two-point periodic excitation is experimentally and numerically investigated in this *** auto-parametric resonance experiment of the test model is conducted to observe and measure the auto-parametric resonance of a continuous beam under a two-point excitation on *** parametric vibration equation is established for the test model using the finite-element *** auto-parametric resonance stability of the structure is analyzed by using Newmark's method and the energy-growth exponent *** effects of the phase difference of the two-point excitation on the stability boundaries of auto-parametric resonance are studied for the test *** with the experiment,the numerical instability predictions of auto-parametric resonance are consistent with the test phenomena,and the numerical stability boundaries of auto-parametric resonance agree with the experimental *** a continuous beam bridge,when the ratio of multipoint excitation frequency(applied to the columns)to natural frequency of the continuous girder is approximately equal to 2,the continuous beam may undergo a strong auto-parametric *** with the present experiment and analysis,a hypothesis of Volgograd Bridge's serpentine vibration is discussed.

关键词： auto-parametric resonance continuous beam bridge model two-point excitation experimental investigation stability analysis vibration of Volgograd Bridge

Research Progress on Bionic Water Strider Robots

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Journal of Bionic Engineering 2024年第2期21卷 635-652页

作者： Jianhao Liu Mingjun shen Ziqiang Ma Xinping Zhou School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan430074China State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan430074China

Biological water striders have advantages such as flexible movement,low disturbance to the water surface,and low *** have developed a large number of biomimetic water strider robots based on their movement mechanism,which have broad application prospects in water quality testing,water surface reconnaissance,and *** article mainly reviews the research progress of biomimetic water strider ***,the biological and kinematic characteristics of water striders are outlined,and some mechanical parameters of biological water striders are *** basic equations of water strider movement are then ***,an overview is given of the past and current work on skating and jumping movements of biomimetic water strider robots based on surface tension and water pressure *** on the current research status of biomimetic water strider robots,the shortcomings of current research on biomimetic water striders are summarized,and the future development of biomimetic water strider robots is *** article provides new insights for the design of biomimetic water strider robots.

关键词： Bionics Water strider Robot Motion of robots on water surface

Transient Stability Analysis and Design of VSGs with Different DC-Link Voltage Controllers

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 593-604页

作者： Chao shen Wei Gu Wanxing sheng Keyan Liu School of Electrical Engineering Southeast UniversityNanjingChina Power Distribution Research Department China Electric Power Research InstituteBeijing 100192China

Virtual synchronous control has been widely studied for the advantages of emulating inertia for voltage source converters (VSCs). A constant dc-link voltage is usually assumed in existing literature to estimate transient stability of virtual synchronous generators (VSGs). However, actual power supply in the dc-side of VSGs is limited and different dc-link voltage controllers are needed to achieve power balance between DC side and AC side. Addition of dc-link voltage controller has great influence on transient behavior of VSGs, which has not been investigated by previous research. To fill this gap, this paper gives insights into the effect of dc-link voltage dynamics on transient stability of VSGs. First, two typical kinds of VSGs with dc-link voltage controllers are introduced. Then, mathematical models considering dc-link dynamics are established and the effect of dc-link voltage controllers on transient synchronization stability of VSGs is revealed through equal area criterion (EAC). It is found that dc-link voltage controller would reduce stability margin of VSGs and design-oriented transient stability analysis is carried out quantitively using critical clearing time (CCT). Finally, simulation results are given to validate correctness of theoretical analysis.

关键词： DC-link voltage dynamics equal area criterion(eac) transient synchronization stability virtual synchronous generator(VSG)

Constitutive modelling of concrete material subjected to low-velocity projectile impact:insights into damage mechanism and target resistance

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第2期25卷 161-182页

作者： shen LIU Xieping HUANG Xiangzhen KONG Qin FANG Center for Hypergravity Experiment and Interdisciplinary Research Zhejiang UniversityHangzhou310058China Institute of Geotechnical Engineering Zhejiang UniversityHangzhou310058China State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of PLANanjing210007China

This paper presents a numerical study to improve the understanding of the complex subject of penetration and perforation of concrete targets impacted by low-velocity *** main focus is on the damage mechanisms and the major factors that account for the target resistance of the *** improved continuous surface cap model recently proposed was *** model was first equipped with element erosion criteria and was adequately validated by comparisons with ballistic *** numerical simulations were carried out where the individual influence of tensile,shear,and volumetric behaviors(pore collapse)of a concrete target on its ballistic performance was *** demonstrated that cratering on the front face and scabbing on the rear face of the concrete target were mainly dominated by its tensile *** major target resistance came from the second tunneling stage which was primarily governed by the shear and volumetric behaviors of the ***,this study captured the pore collapse-induced damage phenomenon during the high-pressure tunneling stage,which has been extensively reported in experiments but has usually been neglected in previous numerical investigations.

关键词： Penetration Perforation Damage mechanism Target resistance Projectile impact Pore collapse