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    Information & Control
    Feasibility Study for Fully Prediction of the Movement Imagery Intention of Lower Limb Ambulation
    Bin ZHOU, Hong WANG, Tan LI, Qin LAN
    2024, 45 (5):  609-618.  DOI: 10.12068/j.issn.1005-3026.2024.05.001
    Abstract ( 454 )   HTML ( 38)   PDF (4776KB) ( 254 )  

    Acquiring intentions before the start of lower limb movement imagery is the key issue in providing precise control strategies for the lower limb neurorehabilitation system. To this end, the feasibility of using electroencephalogram (EEG) signals prior to movement imagery to fully predict the movement imagery start‐stop intention and intention types of lower limb ambulation is investigated. The EEG signal is pre?processed and the movement?related cortical potential (MRCP) is extracted. 15 channels with significant discriminability are selected based on MRCP. The temporal convolutional network models are used to decode the movement imagery intention and intention types of lower limb ambulation from the selected MRCP channel features. The results show that the EEG channel signals selected by MRCP morphology are with significant separable differences in both start‐stop intention and intention types, verifying that using only pre?movement imagery EEG signals is capable of fully prediction the movement imagery start‐stop intention and intention types of lower limb ambulation movement in humans.

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    Secure Electronic Voting Scheme Based on Blockchain and Short Linkable Ring Signature
    Qi-yu WU, Fan YANG, Fu-cai ZHOU, Da FENG
    2024, 45 (5):  619-627.  DOI: 10.12068/j.issn.1005-3026.2024.05.002
    Abstract ( 314 )   HTML ( 17)   PDF (838KB) ( 113 )  

    Surrounding the problems that most of the current electronic voting schemes are centralized and unable to achieve anonymous voting, a secure electronic voting scheme based on blockchain and short linkable ring signature is proposed. By designing a short linkable ring signature scheme and combining with blockchain technology, a specific, secure and efficient electronic voting scheme is constructed. The system model, the formal definition of the algorithms, and the detailed description are provided. Compared with the existing schemes, this scheme allows for large‐scale voting, and supports multiple voting options and automatic counting of votes. The security analysis and experimental results show that this scheme can meet more security goals such as anonymity, unforgeability, and privacy, while still with advantages in terms of computational overhead.

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    Identification of Key Nodes of Acupoint-Disease Network Based on Motif PageRank Algorithm
    Hai ZHAO, Jiu-nan MIAO, Xiao LIU, Xue-long YU
    2024, 45 (5):  628-635.  DOI: 10.12068/j.issn.1005-3026.2024.05.003
    Abstract ( 283 )   HTML ( 16)   PDF (1103KB) ( 82 )  

    Aiming at the problems of poor accuracy and narrow applicability of the existing key acupoint mining algorithms, a high specificity acupoint mining algorithm based on a 3‐node motif is proposed by introducing higher‐order interactions between multiple acupoints in the acupoint‐disease network. Comparing this algorithm with five other acupoint importance assessment algorithms in terms of resolution, network loss, and accuracy, the results show that the key acupoints identified by this algorithm have obvious destructive effects on the connectivity of the network, which indicates that the key acupoints are the core of the topology of acupoint‐disease network and have high synergistic co?operation with other acupoints. The stability of this algorithm ensures the reliability of the key acupoints. From the perspective of the network topology and the high synergy between acupoints, the key acupoints found by the algorithm can be used as the core acupoints in the acupoint network, helping researchers to explore targeted and highly effective combinations of acupoints.

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    Materials & Metallurgy
    Microstructure and Properties of Tempered High Vanadium Semi High Speed Steel Alloy Cladding Layer
    Hang SUN, Wei CHEN, Chang LUO, Chang-sheng LIU
    2024, 45 (5):  636-642.  DOI: 10.12068/j.issn.1005-3026.2024.05.004
    Abstract ( 368 )   HTML ( 7)   PDF (2593KB) ( 115 )  

    In order to meet the demand for rapid repair of roll surface, laser cladding technology was used to clad the self?designed and prepared high vanadium semi high speed steel alloy powder on the surface of roll alloy steel. Considering the difference between the structures of forged steel roll and laser cladding layer, in order to stabilize the structure, the cladding layer was tempered with 500 ℃ and 2 h. The results show that the phase composition of the cladding layer is mainly martensite. The surface of the cladding layer is mainly fine equiaxed crystal, and the intragranular martensite is distributed in parallel in needle shape,which is decomposed into ferrite and carbide after tempering. The average hardness of the cross?section of the cladding layer is 663.4 HV, 1.8 times that of the substrate. The average friction coefficient of the cladding layer is 0.708, the wear rate is 6.142×10-6 mm3·N-1·m-1, the wear performance is 25 times higher than that of the substrate, and the wear morphology is good, in accordance with the wear amount results.

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    Effect of Austenite Grain Refinement on Microstructure and Properties of Ultra‑Heavy EH47 Crack Arrest Steel
    Jiu-xin ZHANG, Xiao-jian REN, Dong-zheng JIN, Yong TIAN
    2024, 45 (5):  643-651.  DOI: 10.12068/j.issn.1005-3026.2024.05.005
    Abstract ( 334 )   HTML ( 8)   PDF (7850KB) ( 117 )  

    The degree of austenite grain refinement in steel for ultra‐heavy ships is limited by conventional processes, resulting in the effect of very small?size austenite grains on the organization and properties of the steel plate being unclear. The effect of austenite grain refinement on the microstructure evolution and mechanical properties of ultra‐heavy EH47 crack arrest steel was investigated by using the secondary austenitization method and thermo mechanical control process. The results showed that the prior‐austenite grain size increased from 14 μm to 28 μm, with the reheating temperature of the test rolled steels rising from 890 ℃ to 1 050 ℃; the decrease of ferrite content reduced the proportion of large angle grain boundary from 57.4% to 40.5%; the volume fraction of martenite/austenite(M/A) islands increased from 2.0% to 6.5%; the yield strength of the steels increased from 440 MPa to 488 MPa. The effective interfacial area per unit volume of 890 ℃ rolled steel was 269.0 mm-1, which was the key reason for its microstructure refinement, homogenization, and 241 J impact energy at -100 ℃.

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    Numerical Simulation of Multiple Physical Fields for the Preparation of Magnesium Hydroxide by Electrodeposition
    Jin-song ZUO, Yue-zhong DI, Dian-qiao GENG
    2024, 45 (5):  652-659.  DOI: 10.12068/j.issn.1005-3026.2024.05.006
    Abstract ( 352 )   HTML ( 6)   PDF (2265KB) ( 82 )  

    For the optimization of the process of preparing flaky magnesium hydroxide by electrodeposition, a multi‐physics coupling method was used to simulate the two‐dimensional unsteady state of magnesium hydroxide preparation by electrodeposition. The voltage, current density, electrolyte flow field, and gas distribution of the electrolyte are obtained under different plate spacing and plate placement depths. The effect of plate parameters on the electric and flow fields during electrolytic cell operation was analyzed. The research results show that the cell voltage decreases when the plate placement depth is reduced. However, reduced plate placement depth hinders electrolyte fluidity, which is detrimental to the reaction. Reducing the plate spacing can enhance mass transfer and reduce the working voltage, but it also worsens the uniformity of the chemical reaction distribution on the plates. To achieve faster electrolyte flow, lower cell voltage, and more uniform current distribution, the plate placement depth should be increased as much as possible, and the plate spacing should be adjusted appropriately.

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    Thermal-Force Bulging Behavior and Efficient Control Method of Electromagnetic Control Roll
    Ting-song YANG, Dun-liang HUANG, Wen-quan SUN, An-rui HE
    2024, 45 (5):  660-667.  DOI: 10.12068/j.issn.1005-3026.2024.05.007
    Abstract ( 298 )   HTML ( 4)   PDF (1929KB) ( 76 )  

    To study the thermal‐force bulging behavior of roll profile electromagnetic control technology (RPECT), the variation laws of the comprehensive roll crown, the thermal‐force contribution roll crown and the ratio of the force crown with the heat of contact zone under different current densities and frequencies were analyzed by finite element method, and the mapping relationship and establishment condition between the heat of contact zone and the thermal‐force bulging ability were explored.The results show that, within the range of the middle and low values of the heat of contact zone, the thermal‐force control ability corresponding to the same value of the heat of contact zone cannot be affected by the magnetic parameters.Therefore, an efficient control strategy of RPECT can be proposed, which takes the heat of contact zone as the bridge value between the input parameter and the control ability.The strategy can quickly achieve the target temperature rise effect of the contact zone by increasing the magnetic parameters, and then obtain the target control ability.Taking the roll gap crown requirement of 20 μm as an example, the comparison between the original and the efficient control strategy shows that the control time of the new strategy can be effectively shortened to 19.57% of the original control time.

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    Analysis on Buffer Oscillation Behavior for Continuous Casting Mold
    Xiang-ning MENG, Ming-jiang WANG, Xiang-yang LIU, Yue-wei SHENG
    2024, 45 (5):  668-674.  DOI: 10.12068/j.issn.1005-3026.2024.05.008
    Abstract ( 304 )   HTML ( 4)   PDF (1357KB) ( 58 )  

    The modified eight?stage non?sinusoidal oscillation waveform of the continuous casting mold leads to less crack defects in the casting billet and has stronger ability to heal such defects. However, the acceleration of the continuous casting mold is larger, which is sensitive to oscillation impact and affects the operation of the mold easily. By rigid clamping and flexible buffering with leaf spring and flexible spring respectively, the inertial force generated by oscillation impact of mold oscillation was reduced, it can achieve the purpose of reducing the oscillation impact. Calculation results show that the stress of spiral spring is larger than that of leaf spring under the same load. When the load of the continuous casting mold is increased by 10%, the increase of maximum stress of spiral spring is 21.23 N more than that of leaf spring. By bisection‐method calculation, it is found that, by allocating 87.5% and 12.5% of the inertia force for leaf spring and spiral spring respectively, more than 90% of the impact from oscillation acceleration is reduced. These results may provide some references for the application of the eight‐stage non‐sinusoidal oscillation technology in continuous casting mold.

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    Mechanical Engineering
    Modeling and Reliability Global Sensitivity Analysis of Motorized Spindles Considering Thermal Errors
    Xian-zhen HUANG, Rui YU, Zhi-yuan JIANG, Zhi-ming RONG
    2024, 45 (5):  675-682.  DOI: 10.12068/j.issn.1005-3026.2024.05.009
    Abstract ( 361 )   HTML ( 10)   PDF (1616KB) ( 77 )  

    Taking the motorized spindle of computer numerical control machine tools as the research object, the influence of its axial thermal elongation on the reliability of the motorized spindle is explored. The Svenska Kullager?Fabriken (SKF) friction torque model is used to analyze the heat generation of the bearing. The convective heat transfer coefficient is set as the boundary heat dissipation condition. The finite element coupling model of thermal analysis is established to solve the temperature and axial thermal elongation distribution of the spindle. The finite element model is compared with the experimental results to verify the accuracy of the established finite element model. Considering the influence of random factors, the reliability analysis model of spindle thermal deformation is established, and the reliability is solved by the Kriging model. Finally, the global sensitivity analysis of the thermal error reliability of the motorized spindle is carried out. The results show that the rotational speed and cooling water flow have a great influence on the reliability, and the axial force and radial force have little influence on the reliability.

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    Mechanical Arm Trajectory Planning Based on B-Spline and Whale Optimization Algorithm
    Zhi-guo LU, Xiao WANG
    2024, 45 (5):  683-689.  DOI: 10.12068/j.issn.1005-3026.2024.05.010
    Abstract ( 336 )   HTML ( 8)   PDF (1152KB) ( 58 )  

    In order to improve the efficiency of mechanical arms, the time optimal trajectory planning method based on the B?spline and whale optimization algorithm(WOA) is proposed. The Monte?Carlo method is used to describe the workspace of the mechanical arms, and then the B?spline is used to interpolate the given path points. According to the performance of each joint of the manipulator, the angular velocity and angular acceleration constraints are introduced, and the boundary conditions are added. After constructing the target function with optimal time, the WOA with inertia weight is used to optimize the running time of the mechanical arm. Finally, using Matlab for simulation, the results show that the algorithm presented is better than the traditional quintic polynomial method in terms of time optimization, and the angular velocity and angular acceleration curve are continuously smoothed, which verifies the validity and feasibility of the algorithm.

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    Design and Experiment of a Vibration-Driven Wall-Climbing Robot for Iron Surface Inspection
    Jian-lei LI, Chen-wei TANG, Xi PENG, Hong-liang YAO
    2024, 45 (5):  690-696.  DOI: 10.12068/j.issn.1005-3026.2024.05.011
    Abstract ( 333 )   PDF (2133KB) ( 54 )  

    A vibration?driven wall?climbing robotic prototype has been studied and tested to move on horizontal to vertical wall sunfaces, which can be developed for high‐risk tasks such as the visual inspection of iron wall surface. An elastic substrate with asymmetric stiffness is designed, and the dynamics model of the vibration‐driven wall‐climbing robot is developed based on the Coulomb dry friction model, with a rotor vibration motor?spring as the actuator. The wall?climbing motion characteristics of the robot are investigated by numerical simulation, and the effects of actuator excitation frequency, wall inclination angle, and permanent magnet attraction on the average speed of the robot are analyzed. The wall motion experiment of the vibration‐driven wall‐climbing robot prototype is carried out. The results show that the average speed of the robot can be effectively improved by reasonable configuration of the permanent magnetic attraction and the excitation frequency, the average wall‐climbing speeds of 10.6 mm/s and 16.7 mm/s are achieved on the 30° and 90° walls, respectively, whereas the forward motion and backward motion can be switched by regulating the excitation frequency.

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    Method for Bearing Fault Quantitative Diagnosis Based on MTF and Improved Residual Network
    Ling-xuan LI, Zhen-wei MA, Ze-jun YU, Zhuang XING
    2024, 45 (5):  697-706.  DOI: 10.12068/j.issn.1005-3026.2024.05.012
    Abstract ( 320 )   HTML ( 2)   PDF (2386KB) ( 74 )  

    Different from the current rolling bearing fault diagnosis which mainly focuses on the qualitative analysis stage, a quantitative fault diagnosis method for rolling bearings based on image classification is proposed. The overlapping sampling method is used to enhance the one?dimensional time series data, and then the Markov transition field (MTF) method is used to convert the one?dimensional time series data into two?dimensional images, which provide two?dimensional image samples for inputting into the neural network model and retain the time?domain information. The ResNeXt and ResNeSt modified residual networks with fine?tuning processing based on transfer learning are built and trained to classify fault images and realize fault diagnosis. The confusion matrix method and t?distributed stochastic neighbor embedding(t?SNE) visualization method are used to carry out experiments. The results show that the proposed method for rolling bearing fault diagnosis can realize the quantitative diagnosis of multi?working condition rolling bearing fault, and has higher diagnosis accuracy and faster training speed.

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    Resources & Civil Engineering
    Conductance Measurement of Water Vapor by the Time-Ratio Method
    Jian GENG, Xiao-dong WANG, Mei-ru GUO, Zheng-yi REN
    2024, 45 (5):  707-712.  DOI: 10.12068/j.issn.1005-3026.2024.05.013
    Abstract ( 322 )   HTML ( 2)   PDF (976KB) ( 62 )  

    There are currently few methods available to measure the conductance of water vapor through an orifice. The feasibility of the pressure rising method to measure the conductance of water vapor is analyzed by combining theory with experiment, indicating that the measurement error of this method increases with the decrease of intake volume, which is due to the strong adsorption characteristic of water vapor. To accurately obtain the relationship between the conductance of water vapor and the inlet pressure, a new method called the time-ratio method is proposed. This method calculates conductance by measuring the time of pressure change, reducing the effect of water vapor adsorption on the measurement effectively. Based on this method, a device is developed to provide a flow rate in the range of 3.7×10-9~1.5×10-5 Pa·m3·s-1. The measurement and theoretical values of conductance have good consistency, and the relative standard uncertainty of this time?ratio method is 3.3%.

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    Debris Flow Susceptibility and Hazard Assessment in Fushun City Based on Hydrological Response Units
    Shan-jun LIU, Shi-yao LIU, Lian-huan WEI, Dong-lin LYU
    2024, 45 (5):  713-720.  DOI: 10.12068/j.issn.1005-3026.2024.05.014
    Abstract ( 293 )   HTML ( 3)   PDF (7595KB) ( 80 )  

    Targeting at the problems of fuzzy evaluation system and neglect of triggering factors such as rainfall in the susceptibility and hazard assessment of debris flows, a study was conducted in the Fushun City based on analysis of the development and distribution patterns of debris flow disasters, the analytic hierarchy process method was utilized to assess the susceptibility and disasters of debris flow, using hydrological response units as evaluation units. The assessment accuracy is evaluated by incorporating existing debris flow disaster points. The results show that among the 42 existing debris flow disaster points, 36 are located in the high and extremely high susceptibility areas (accounting for 85.71%), and 33 are located in the high and extremely high hazard areas (accounting for 78.57%). This indicates that the susceptibility and hazard assessment results are reliable and consistent with the current development situation of debris flow disasters in Fushun City.

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    Optimization of CO Sensor Carrying Position of Mine Intelligent Inspection Vehicle
    Jin-rui ZHANG, Xi-wen YAO, Kai-li XU, Xiu SUN
    2024, 45 (5):  721-728.  DOI: 10.12068/j.issn.1005-3026.2024.05.015
    Abstract ( 291 )   HTML ( 2)   PDF (1606KB) ( 58 )  

    To improve the reliability of CO volume fraction monitoring data collected by mine intelligent inspection vehicles, the wind flow distribution and the spatial‐temporal evolution law of CO volume fraction in the excavation roadway at the -630 m level of Jiaojia Gold Mine in Shandong province are analyzed by using a computational fluid dynamics (CFD) software. The study results show that the wind flow in the zone between the ventilation duct’s mouth and the heading face is unstable, leading to the formation of the vortices that disrupt the volume fraction distribution of gas. The CO transducer should be carried as high as possible in the car body because the CO volume fraction peak is mostly at the top of the roadway under the effect of self‐characterization and laminar flow near the wall. The variation of CO volume fraction on both sides is unstable during the attenuation section, thus the inspection vehicle should be put in the middle of the roadway when travelling. The simulation results are validated by comparing the attenuation variation of CO volume fraction with ventilation time in an excavation roadway.

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    Mechanical Properties and Reinforcement Method of Misaligned Thick Plate Cross Joints in Steel Bridge
    Chong SHEN, Qing-tian SU, You-sheng CHEN
    2024, 45 (5):  729-737.  DOI: 10.12068/j.issn.1005-3026.2024.05.016
    Abstract ( 278 )   HTML ( 4)   PDF (3845KB) ( 61 )  

    Aiming at the problem of misalignment defects in the cross joint of thick plates in steel bridges, the finite element method was used to study the influence of misalignment defects on the mechanical properties of cross joints of thick plate, and a reinforcement method of welding separated steel plates was proposed and the size of the steel plate for reinforcement was optimized. The results show that misalignment defects have a signficiant effect on the mechanical properties of cross joints of thick plate, and the vertical stress increases significantly under the influence of additional bending moment. The proposed reinforcement method of welding separated steel plates makes the vertical support plate of cross joint bear most of the axial force and bending moment after reinforcement. The key section for design is located near the weld at the bottom of the steel plate for reinforcement, and the efficiency of reinforcement can be improved by increasing the height of the steel plate for reinforcement, up to 48%. Different sizes of steel plates for reinforcement are recommended for cross joints with different misalignments, which can provide a reference for the reinforcement methods of misaligned thick plate cross joints in similar projects.

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    Interpretable Deep Learning Prediction Model for Compressive Strength of Concrete
    Wei-qi ZHANG, Hui-ming WANG
    2024, 45 (5):  738-744.  DOI: 10.12068/j.issn.1005-3026.2024.05.017
    Abstract ( 347 )   HTML ( 6)   PDF (2982KB) ( 115 )  

    To quickly and accurately predict the compressive strength of concrete, a prediction model is established using deep learning technology. The model is automatically optimized and adjusted using the Bayesian optimization algorithm, and the prediction results are analyzed by combining with the SHapley Additive exPlanations (SHAP) interpretable method, which overcomes the problem of the “black box” of the prediction model. The deep learning model is used to mine the potential law between each input feature parameter and compressive strength, the importance of the parameters on the compressive strength prediction results and the influence law is analyzed by visualizing the SHAP values of the input feature parameters. The results show that the constructed deep learning model outforms other traditional models. The SHAP analysis results are consistent with the experimental results, and the model better reflects the complex nonlinear relationship among the characteristic parameters, which can provide the basis and reference for the engineering design of concrete materials.

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    Management Science
    Financing Mode Selection Strategies of Closed-Loop Supply Chain with Capital Constrainted Manufacturer
    Chun-yi LIU, Tian-hui YOU, Bing-bing CAO
    2024, 45 (5):  745-752.  DOI: 10.12068/j.issn.1005-3026.2024.05.018
    Abstract ( 342 )   HTML ( 6)   PDF (807KB) ( 82 )  

    Aiming at the financing mode selection problem of a closed?loop supply chain consisting of a retailer, a recycler, and a capital constrainted manufacturer, the revenue functions of the manufacturer, retailer, recycler, and closed‐loop supply chain are constructed when the capital constrained manufacturer can get financing from the retailer (internal financing) or the bank (external financing), respectively, and based on the Stackelberg game, the optimal pricing and return rate strategies under two financing modes are given. On this basis, by comparing the optimal decisions and revenue of the recycler, retailer, manufacturer, and closed‐loop supply chain under different financing modes, the financing mode selection strategies are given from different perspectives. The research results show that under certain conditions, the retailer providing financing services are beneficial for the manufacturer, retailer, recycler and closed‐loop supply chain.

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    Location Choice of Chinese Multinational Enterprises in Countries of “the Belt and Road”: the Role of Relational Assets
    Rui GAO, Xiao-jun DU
    2024, 45 (5):  753-760.  DOI: 10.12068/j.issn.1005-3026.2024.05.019
    Abstract ( 302 )   PDF (706KB) ( 36 )  

    From the relationship perspective, combined with the regionality of enterprises’ specific advantages, and through the Logit regression method, the foreign direct investment events of Chinese multinational enterprises in 31 countries of “the Belt and Road” from 2009 to 2019 were taken as the research samples to explore the impact of relational assets on the location investment with political risk attributes of Chinese multinational enterprises along the “the Belt and Road” and discuss the regulating effect of bilateral diplomatic relations and market competition intensity. The results showed that multinational enterprises with host country relational assets tend to invest in high political risk locations, and friendly bilateral diplomatic relations and high market competition intensity can significantly enhance the positive impact between them.

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