Table of Content

25 October 2025, Volume 36 Issue 10

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Intelligent Decision-making for Assembly Processes of Micro-device Products

Lingling SHI, Yimin DU, Lili GUO, Zhijing ZHANG, Xin JIN, Jiadi LI

2025, 36(10):  2159-2170.  DOI: 10.3969/j.issn.1004-132X.2025.10.001

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To solve the problems that the assembly process planning of micro-device products relies on manual experience heavily， a knowledge-driven fine-grained micro-device assembly process planning method was proposed. And a micro-device assembly process decision software integrating product and system knowledge was developed. This planning method took the resource constraints of the assembly systems into account， and planned the assembly processes of micro-devices from process， steps， and process parameters. Based on interval-type hesitant fuzzy entropy， a mixed attribute matching weight parameter determination method ensured the effectiveness of the process decision algorithm. The developed decision system realized rapid decision-making of the assembly processes of micro-device products.

Aerodynamic Optimization of Radial Turbines Based on Surrogate Model of Pre-screened Strategies and DFFD Parameterization

Tianqi WANG, Jiang CHEN, Hang XIANG, Xiaofei SONG

2025, 36(10):  2171-2178.  DOI: 10.3969/j.issn.1004-132X.2025.10.002

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There were some problems such as difficult geometric control， many control variables and low optimization efficiency in aerodynamic optimization of three-dimensional complex blade surfaces of radial turbines. To solve these problems， multi-degree-of-freedom parameterization of radial turbine runner and blade multidimensional geometry were implemented based on DFFD method. Then an differential evolution algorithm assisted by surrogate models of pre-screened strategies（Pre-SADE） was introduced. Finally， a data-driven three-dimensional aerodynamic optimization platform for centripetal turbines was constructed by combining python and batch script of process automation. The platform was used to carry out the joint optimization design of flow channel-static/rotating blades for the radial turbines. The results show that after optimization， the adiabatic efficiency and mass-flow of the design point of the centripetal turbines are increased by 1.66% and 1.7% respectively， which effectively reduces the shock intensity in the guide vane channel and the shock loss on the suction surfaces of the guide vane， and the efficiency characteristics of the design rotational speed are improved in all working conditions. Finally， the method and platform may ensure the aerodynamic optimization efficiency， and effectively reduce the optimization variables and sample real evaluation times， significantly improve the optimization efficiency， and meet the rapid and elaborate optimization design requirements of radial turbines.

Molecular Dynamics Simulation of Microscopic Crack Initiation and Extension Mechanism in 8Cr4Mo4V Bearing Steels

Tianyu MA, Gu GONG, Hongrui CAO, Jianghai SHI, Xunkai WEI, Lijun ZHANG

2025, 36(10):  2179-2189.  DOI: 10.3969/j.issn.1004-132X.2025.10.003

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To investigate the influences of cementite on the mechanics properties of the matrix and the initiation and propagation of microcracks in 8Cr4Mo4V bearing steels， molecular dynamics models were used to systematically analyze the effects of cementite's geometric parameters （such as shape， size， and position） on crack initiation and extension mechanism. And combined with cohesive force theory， the characteristics of interface crack propagation were studied. The results indicate that cementite significantly enhances the mechanics properties of the bcc-Fe matrix， with smaller cementite particles providing a more pronounced strengthening effectiveness. While the shape and position of cementite exert a relatively minor impact on overall mechanics performance， sharper inclusions accelerate crack propagation， and the position of inclusions determines the crack propagation path. Furthermore， interfaces between the bcc-Fe matrix and cementite， as well as twin boundaries with larger misorientation angles， exhibit increased resistance to crack initiation and propagation.

Experimental and Molecular Dynamics Simulation for Mechanics Properties of 45 Steel Treated by Plasma

Zhaobo PENG, Jinxing KONG, Dongxing DU, Hankun LUO, Hen YUE

2025, 36(10):  2190-2197.  DOI: 10.3969/j.issn.1004-132X.2025.10.004

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To investigate the influences of plasma treatment on the mechanics properties of 45 steel， the changes of mechanics properties of 45 steel before and after treatment were studied by combining experiments and molecular dynamics simulation. The test results show that the hardness and tensile mechanics properties of 45 steel are obviously decreased after plasma treatment. Under the treatment durations of 1， 5 and 10 min， the nano-hardnessis decreased by 12%， 21% and 28% respectively， and the longer the treatment time， the better the modification effect， and the duration of the modification effect is more than 20 h. When the thickness of tensile specimens is as 0.1， 0.15 and 0.2 mm， the tensile strength decreases by 3.3%， 4.5% and 5.3%， and the elongation after fracture decreases by 39.69%， 42.17% and 42.49%， respectively. The molecular dynamics simulation results show that the number and strength of Fe-Fe bonds in 45 steel are reduced after plasma modification， resulting in the reduction of yield strength and surface hardness of the materials， which is basically consistent with the experimental results.

Influences of Rotational Speed and Flow Rate on Pressure Pulsations of a Rim-driven Axial Flow Pump

Mengjie CHEN, Zhuo ZHANG, Wu OUYANG, Chenxing SHENG, Bao LIU, Wei LIU

2025, 36(10):  2198-2206.  DOI: 10.3969/j.issn.1004-132X.2025.10.005

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A novel RDP generated pressure pulsations during operations， which might negatively impact pump performance and system stability. The numerical simulation was employed to analyze the external characteristics and internal flow patterns of RDP under different rotational speeds and flow conditions. Utilizing POD， the main energy modes were extracted through spatiotemporal feature decomposition to investigate the influences of rotational speed and flow rate on the pressure pulsation at the trailing edges of the impeller blades， revealing the relationship between nonlinear dynamics and fluid-structure interaction phenomena. The results show that each rotational speed corresponds to a distinct optimal operating point， with the optimal point shifting towards lower flow rates as the rotational speed decreases. Moreover， the pressure pulsations are predominantly governed by nonlinear dynamics behavior， with nonlinear interaction effects between the impeller blades and guide vanes becoming more pronounced at lower rotational speeds and higher flow rates.

Nanosecond Laser Machining of Spiral Grooves of Dry Gas Seal Rotational Ring Surfaces

Wenqian LI, Zhanqiang LIU, Jinfu ZHAO, Bing WANG, Yukui CAI

2025, 36(10):  2207-2214.  DOI: 10.3969/j.issn.1004-132X.2025.10.006

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An experimental study on the nanosecond laser processing of the spiral groove on the dry gas seal rotational ring surfaces made of GH4169 was carried out. Orthogonal tests and one-factor methods were utilized to reveal the effects of laser power， scanning speed， filling spacing and repetition frequency on the spiral groove depth and bottom roughness Ra， and to determine the appropriate combination of laser processing parameters. The results show that the greatest influence on the depth of the spiral grooves on the surfaces of GH4169 alloy is the laser power， followed by the repetition frequency and the scanning speed， and the greatest influence on the roughness of the groove bottoms is the scanning speed， followed by the repetition frequency and the scanning spacing. With the laser power of 18 W， scanning speed of 40 mm/s， fill spacing of 0.005 mm， and repetition frequency of 50 kHz， the spiral grooves on the machined rotational ring surfaces is able to meet the machining requirements of groove depth of 7 μm， and groove bottom roughness of Ra≤0.8 μm.

Flow Field Characteristics of Mesoscopic Impinging Jets under Influences of Wall Micro-defects

Rui HONG, Jianjun HU, Yang XIAO, Yaolan JIN, Jing YAO, Xiangdong KONG

2025, 36(10):  2215-2223.  DOI: 10.3969/j.issn.1004-132X.2025.10.007

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In order to study the effects of micro-defects caused by erosion wear and cavitation on flow field law and fluid energy conversion characteristics after long-term service of the nozzle-receiver pilot stage of the jet pipe servo valves. Micro-PIV technology was used to directly test the flow structure and vortex distribution in the square cavity when the original mesoscopic close-range jet impacted the micro-defect target plate. The influences of micro-defect size， shape， and location on vortex morphology and the evolution were investigated， and the underlying mechanism governing the splitting and merging phenomena of vortex cores within a square cavity were elucidated. The results show that the existence of wall micro-defects directly affects the energy transfer and dissipation of the wall jets， leading to a significantly different vortex structure and energy distribution in the jet gap and square cavity than that when there are no defects. As the size of the micro-concave increases， the circular-like vortex pairs in the square cavity on both sides show a tendency to gradually split and move away from the bottom wall. While as the size of micro-convex increases， the cocoon-like vortex pairs in the square cavity on both sides show an evolutionary law of gradually normalization and moving closer to that of the bottom wall.

Research on Differential Steering Mechanism Based on Tire Cornering

Biaofei SHI, Xiaoming YE, Haoyu LYU, Feng LAI

2025, 36(10):  2224-2231.  DOI: 10.3969/j.issn.1004-132X.2025.10.008

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Differential steering based on tire cornering suited low-speed， large steering radius scenarios of distributed drive electric vehicles（DDEV） without steering mechanisms. In order to study the mechanism of differential steering based on tire cornering， a 7-degree-of-freedom DDEV dynamic model with no steering mechanism and PAC2002 tire model were established. Then， the formation mechanism of differential steering was analyzed and a systematic analysis method from the input of differential longitudinal force to the output of vehicle steering radius of differential steering was proposed by considering the tire force longitudinal-lateral-coupling characteristics. Leveraging the proposed systematic analysis method， the stability of differential steering and the influences of differential longitudinal force， vehicle parameters and tire characteristics on steering radius were studied. Finally， a Carsim/Simulink joint simulation platform was established to simulate differential steering under different influencing factors. The results show that within the range of tire cornering， the larger the differential longitudinal force， the larger the ratio of track width to wheelbase， and the smaller the tire lateral stiffness， the smaller the steering radius.

Research on First-passage failure and Reliability Analysis of Maglev Trains

Weiwei LIU, Kuo LI, Xi YU, Shuangquan TANG

2025, 36(10):  2232-2240.  DOI: 10.3969/j.issn.1004-132X.2025.10.009

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In order to obtain the first-passage failure characteristics of maglev trains， a dynamics model was established for electromagnetic suspension trains under the action of parametric excitation and external excitation， the first-passage reliability function was established under the framework of Hamilton's theory， and the backward Kolmogorov equation was solved numerically by using a new type of Crank-Nicolson difference method to investigate the effects of the initial energy， stochastic external excitation， stochastic parametric excitation， low stochastic excitation and train speed on the first-passage of maglev trains. The results show that the increase of initial energy will make the first-passage time earlier. The increase of stochastic external excitation and stochastic parametric excitation will make the average first-passage time decrease， where the influences of stochastic external excitation on the average first-passage time are larger than that of stochastic parametric excitation， and the first-passage hardly occurs under the action of low stochastic excitation. As the train speed increases， the average first-passage time decreases and the maximum probability of first-passage failure increases.

Improvement of Fatigue Performances of AISI 4340 Steel Thread Root by Rolling Processes

Hongwei LIU, Renke KANG, Xianglong ZHU, Haotian MU, Fangzhou HE, Mo CHEN

2025, 36(10):  2241-2248.  DOI: 10.3969/j.issn.1004-132X.2025.10.010

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The rolling process was adopted to improve the fatigue performances of AISI 4340 steel bolt threads， and the optimal rolling parameters were determined by orthogonal testing with the bolt fatigue life as the evaluation index. The surface integrity and fatigue life of unrolled， under-rolled， optimally rolled， and over-rolled thread were analyzed to elucidate the thread fatigue mechanism. The results show that the rolling parameters have a significant effect on the fatigue life of AISI 4340 steel threads， with the order of significance as follows： rolling depth， spindle speed， rolling times. The optimal parameters are as： rolling depth 0.09 mm， spindle speed 40 r/min， and 3 rolling times. The surface integrity improvement of under-rolled samples is low， and the over-rolled samples have the largest degree of work-hardening but damaged the thread root surface. The surface roughness Sa and Sq of thread root with the optimally rolled are reduced to 0.124 μm and 0.165 μm respectively， and the residual compressive stress is increased to -247.1 MPa. In addition， transition hardening is avoided with an increase in micro-hardness and the formation of a deeper deformation layer. Due to the synergistic improvement of surface roughness， micro-hardness and residual stress of the threaded root with the optimal rolling parameters， the fatigue strength was increased by 50% compared to unrolled bolts. The results indicate that the rolling process with reasonable parameters achieves the purpose of high-quality strengthening and may effectively solve the problems of high-fatigue fracture of bolts.

Power Generation Performance of Hybrid Piezoelectric Vibrator Based on Rotational Magnetic Force-wind Induced Vibrations

Xiaodong YAN, Gongbo ZHOU, Ping ZHOU, Lianfeng HAN, Qing LI, Shuang CAO

2025, 36(10):  2249-2257.  DOI: 10.3969/j.issn.1004-132X.2025.10.011

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Aiming at the problems of low energy harvesting efficiency in traditional single wind-induced vibration piezoelectric vibrator， a hybrid piezoelectric vibrator was proposed based on rotational magnetic force and wind-induced vibrations. With the wind energy from an underground mechanized mining face as the research backdrop， a hybrid piezoelectric vibrator model was conceived. A magnetic coupling model was formulated to elucidate the magnetic variation traits of the piezoelectric vibrator across various magnetic moments. A simulation was conducted to scrutinize the flow field characteristics of the designed piezoelectric vibrator. Lastly， experimental validation was executed to substantiate the power generation performance of the piezoelectric vibrator. The results indicate that the overall power generation of the designed piezoelectric vibrator increases with the diameter ratio， and there is an optimal magnetic moment and aspect ratio for achieving the best power generation performance of the hybrid piezoelectric vibrator. When the wind speed v=3.5 m/s， the maximum power generation reaches over 0.72 mW. Compared with a single wind-induced vibration piezoelectric vibrator， the proposed hybrid piezoelectric vibrator with rotating magnetic force and wind-induced vibrations increases the power generation by more than 166.7 %.

Flow Field Disturbance and Stable Operation Characteristics of Marine Steam Turbines under Extreme Variable Conditions

Yuang SHI, Lei ZHANG, Luotao XIE, Luhan YIN

2025, 36(10):  2258-2265.  DOI: 10.3969/j.issn.1004-132X.2025.10.012

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To identify the mechanism of flow field disturbance in marine steam turbines under extreme variable conditions and ensure their safe and stable operations， a full-size three-dimensional through-flow and structural model of the high power density steam turbines was established. By introducing high-precision multi-layer grid division technology， combined with the Euler multiphase flow model and turbulence model， a numerical calculation method was proposed for internal steady-state and transient flow fields of steam turbines under a wide range of variable conditions. The analysis of flow field disturbance characteristics under variable conditions of the steam turbines was carried out， revealing the internal flow characteristics of the steam turbines under extremely low flow conditions， and the threshold values of instability flow and the stable operation power flow of the whole machine were determined. A unidirectional flow-solid coupling calculation method and process for the last stage of the steam turbines were proposed based on the high-precision flow field distribution basic data. The static and dynamic stress variation laws of key parts of the last stage blades were calculated， the flow-induced vibration excitation source of the last stage blades was identified， and the instability characteristics were analyzed. The vibration characteristics of the blades were evaluated， providing technical reference for the safe and stable operations of the steam turbines.

Cavitation Flow and Cooling Mechanism in Mechanical Seals with Double Row Reverse Step

Xuehong MA, Congcong LI

2025, 36(10):  2266-2273.  DOI: 10.3969/j.issn.1004-132X.2025.10.013

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The thermal-hydrodynamic lubrication （THD） numerical model of mechanical seals with double row reverse Rayleigh steps was established by the CFD method， and the THD characteristics and cavitation flow laws were investigated. The results indicate that large-scale cavitation occurs in the double row reverse Rayleigh step， forming a low-temperature region， which has a significant cooling effect on the liquid film end face and sealing ring. It may be seen from the changes in speed， pressure， and groove depth that larger cavitation areas are correlated with high-speed， low-pressure and shallow grooves. The level of cavitation cooling depends on the cavitation area， and on the cavitation intensity. Temperature valleys and peaks are formed at the rupture and reformation boundaries of the liquid film in the groove， and vortex flow is formed under the combined action of pressure flow and shear flow. The edge position of the vortex corresponds well with the position of cavitation regeneration and the end of the high-temperature zone. The formation of large-area cavitation effect in the reverse step groove also leads to good suction effect in the seal， greatly reducing the seal leakage rate.

Kernel Regularization Optimal Iterative Learning Control Based on Trajectory Learning under Actuator Constraints

Liangliang YANG, Hong CHEN, Wenqi LU

2025, 36(10):  2274-2283.  DOI: 10.3969/j.issn.1004-132X.2025.10.014

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To address the issues of non-repetitive trajectories tracking and potential actuator saturation， a kernel regularization optimal iterative learning control （KROILC） algorithm was proposed. The kernel-based regularization method was used to estimate the system's impulse response from input-output data. Several zero-mean Gaussian process kernels were demonstrated for this purpose. The estimated impluse response was applied to the controller， and actuator constraints were weighted in the objective function. Initial feedforward input after trajectory changes was learned iteratively. Experimental results on a brushless DC motor show that the proposed algorithm achieves optimal tracking for non-repetitive trajectories while maintaining actuator stability.

Deformation/Attitude Coupling Dynamics and Control of Space Membrane Antennas

Zuqing YU, Tingyu QI, Zhuo LIU, Qinglong TIAN

2025, 36(10):  2284-2291.  DOI: 10.3969/j.issn.1004-132X.2025.10.015

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Aiming to address the challenging issues of multiscale coupled dynamics modeling and control for flexible bodies during the spin deployment of space membrane antennas， a hybrid modeling approach and attitude decoupling control strategy was proposed herein. A hybrid element dynamic model integrating membrane and hollow support rods was developed using thin plate elements and circular cross-section beam elements based on ANCF. Nonlinear constitutive relations were introduced to characterize the tensioned-relaxed state transitions of space membrane antennas during deployment. By leveraging ANCF's capability to describe flexible body deformation and rigid body rotation simultaneously， polar decomposition was performed on the gradient matrices of selected nodal position vectors to extract attitude information. A proportional-derivative （PD） torque control scheme was subsequently implemented based on the derived posture parameters. Simulation results demonstrate that the proposed dynamics modeling and control methodologies may achieve asymptotic convergence of attitude tracking errors effectively.

Research on Vibration Fatigue of Pipeline Inspection Gauge Sealing Discs under Influences of Pipeline Defects

Xingyu WANG, Yanbao GUO, Zheng ZHANG, Zhangyu QIAO, Fa GAO, Jinzhong CHEN, Chang LIU

2025, 36(10):  2292-2299.  DOI: 10.3969/j.issn.1004-132X.2025.10.016

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When the pipeline inspection gauge was passing through defects， the vibrations and fatigue damages of sealing discs were intensified， affecting inspection reliability and leading to safety incidents. The ABAQUS software was used to investigate the interface contact vibration characteristics of sealing discs at defect locations within the pipeline， focusing on the intrinsic connections between the evolution of contact vibration behavior， the attenuation function， fatigue weak point locations， and fatigue life. The results show that the vibration processes of the sealing discs when passing through defects involve four stages： impact， deformation， near-elastic， and elastic. The dynamic stress amplitude of elastic vibration is found to follow an exponential decay pattern. The total number of vibrations is observed to increase with defect depth and friction coefficient， which is closely related to fatigue life. Fatigue weak points are concentrated at the contact points and the edges of the clamp， which is consistent with actual working conditions. The accuracy and feasibility of the proposed method are validated.

Load Carrying Characteristics of Permanent Magnetic Thrust Bearings with Modularized Multi-cellular Elements

Wuchao CHEN, Xiangdong YU, Kun HE, Jimin ZHANG

2025, 36(10):  2300-2305.  DOI: 10.3969/j.issn.1004-132X.2025.10.017

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Permanent magnet thrust bearings featured high rotational speed， low noise， and frictionless operations， but suffered from low load carrying capacity and non-universal structures. Aiming at these problems， a modular multi-cellular element structure of permanent magnet thrust bearings was proposed， where four permanent magnets formed a single cell element. By adjusting the number and arrangement of cell elements， various nested and crossover configurations were realized. Based on the finite element software， the bearings with two-layer nested two-pole crossover， four-layer nested four- pole crossover， six-layer nested six- pole crossover and eight-layer nested eight-pole crossover were constructed with a total of four structures， and the load carrying performances of the different structures were analyzed. The simulation results show that the bearing capacity first increases and then decreases with the increase of axial displacements， and the maximum axial bearing capacity of the permanent magnet thrust bearings of the four configurations was as 6.78，50.52，136.85，288.9 kN. Finally， a four-layer nested four-pole-crossed permanent magnet thrust bearing prototype was fabricated and the axial bearing capacity experimental validation was carried out， and the results show that the maximum load capacity of the experiments is 4.2% lower than the simulation value.

Load Optimization of Pin Anti-rotation Mechanisms for Electric Scroll Compressors

Xingwang LIU, Song TIAN, Xiaoming LIU, Yongwei JIANG, Zhen SUN, Kuo LI

2025, 36(10):  2306-2311.  DOI: 10.3969/j.issn.1004-132X.2025.10.018

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Aiming at the problems that the pin anti-rotation mechanism of electric scroll compressors was prone to wear and even fracture due to large contact loads， several methods were studied to optimize the load on the mechanisms. By analyzing the orbiting moments of the orbiting scroll， the variation laws of the orbiting moments induced by gas forces and rotating back-pressure oil forces with rotational speed were investigated. A mechanics model of the pin anti-rotation mechanisms with clearances under the orbiting moments was established， and the contact angles between the ring and pins were calculated for different numbers of pins. Load reduction methods were studied from three aspects： the number of pins， tooth tip modification， and the bottom plate structure of the orbiting scrolls. The anti-rotation mechanisms of a prototype was optimized using these methods， and the contact loads and lubrication conditions of the pins were compared before and after optimization. The results show that the orbiting moments caused by back-pressure oil increase with rotational speed. Increasing the number of pins， reducing the modification angle and offset of tooth tips， adjusting the position of the primary balance groove， and adding an inner pin at the center of the ring groove when the number of pins is even may effectively reduce the contact loads on the pins. After optimization， the peak contact forces of the pins decrease by 70.1%， the average contact forces decrease by 61.3%， and the lubrication conditions of the pins are improved.

Mechanism Analysis of Material Remove and Subsurface Layer Damages for SiC during Nanocutting Processes

Jingjing CHEN, Sha CHEN, Haiyan ZHU, Junjun YUAN, Zeyu LUO

2025, 36(10):  2312-2321.  DOI: 10.3969/j.issn.1004-132X.2025.10.019

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The plastic removal mechanism of SiC was investigated by molecular dynamics method and micro-cutting experiments. It is found that the high lattice distortion effectiveness of SiC materials induced by extrusion force may lead to the reverse flow trend of the atomic vector displacement in elastic stages during nanoscale cutting， and the eddy current trend of the atomic vector displacement occurs in elastoplasticity deformation stages. The plastic deformation-mediated amorphous layer coverages， the phase transformation from cubic structure to wurtzite structure， and the formation of shear bands and cracks on the machined surfaces of SiC nanocutting obtained from molecular dynamics simulations are consistent with the experimental results.The random surface roughness in machined surface areas is easy to form a stepped type， which increases as cutting temperature and speed increases. The plastic removal mechanism in nanocutting processes is that the high pressure and high temperature induced by loads in closely contact areas between cutting tool and SiC workpiece result in the shear band flow outflow from the rank face and the cutting morphology and configuration are formed finally. The subsurface damage degree gradually decreases with cutting distance and cutting speed increases. Nevertheless， the subsurface damage degree gradually increases with the increase of cutting temperature and depth. Furthermore， with cutting speed increase， chip morphology of SiC materials gradually changed from convolution state to bar state， and the chip morphology is of mainly convolution as the temperature of system increases.

A Real-time Measurement Method for Equivalent Circuit Parameters of Piezoelectric Transducers

Runxiang LI, Yuheng YANG, Chenchen MENG, Yuebo JI

2025, 36(10):  2322-2328.  DOI: 10.3969/j.issn.1004-132X.2025.10.020

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The existing measurement methods of equivalent circuit parameters of piezoelectric transducers are complex and easy to affect the normal operation of transducers， so it is difficult to measure the equivalent circuit parameters of transducers in real time. In order to solve this problem， based on the analysis of the phase-frequency characteristics of the transducer， a real-time measurement method of the equivalent circuit parameters of the piezoelectric transducer was proposed based on the least square fitting， and the corresponding measurement system was designed. The series resonant frequency of the transducer was locked by frequency sweep and peak current detection， and the driving frequency was fine-tuned several times near it to obtain the impedance angles at both ends of the transducer at the corresponding frequency. Based on the minimum residual sum of squares， a set of model parameters with the highest degree of fitting was obtained， and the equivalent circuit parameters of the piezoelectric transducer were solved by combining the deduced calculation formula. Using simulation and experiments to test the measurement method. The simulation results show that the relative error of the measurement results relative to the impedance analyzer is within ±1%. The experimental results further validate the effectiveness of the measurement method. The measurement results have a relative error of within ±4% compared to the impedance analyzer， and are applicable in cases of load variation. The program running time is 185\mathrm{\mu }\mathrm{s}. This method has high measurement accuracy and fast operation speed， enabling real-time measurement of the equivalent circuit parameters of piezoelectric transducers.

Prediction of Three-dimensional Machined Surface Topography of KDP Crystals Based on Deep Learning

Zulong YAN, Qilong PANG, Jianlong XIONG

2025, 36(10):  2329-2334.  DOI: 10.3969/j.issn.1004-132X.2025.10.021

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The surface morphology of potassium dihydrogen phosphate（KH₂PO₄， KDP） machined by single point diamond turning was the research objects. The low， mid， and high-frequency wavelengths and amplitudes of the three-dimensional surface were extracted by CWT and power spectral density（PSD） as sample sets. Cutting parameters were treated as key variables， and bi-directional long short-term memory （BiLSTM）， gated recurrent units（GRU）， random forest（RF）， and convolutional neural network（CNN） were developed to predict the wavelengths and amplitudes of different frequency bands， ultimately enabling the prediction of the three-dimensional machined surface topography. The results indicate that the BiLSTM model demonstrate superior prediction performance for mid and high-frequency wavelengths， as well as low and high-frequency amplitudes， with average percentage errors of 2.14% and 3.03% for mid and high-frequency wavelengths， and 4.62% and 7.19% for low and high-frequency amplitudes， respectively. The GRU model excelles in predicting low-frequency wavelengths and mid-frequency amplitudes， with errors of 3.83% and 5.68%. The predicted three-dimensional surface topography closely matches experimental results from the validation sets. The correspondence between cutting parameters and the three-dimensional machined surface of KDP crystals was revealed by combining continuous wavelet transform， power spectral density， and deep learning methods and the correctness was verified.

Coordination Control of Dual-valve Electrohydraulic Servo Systems Based on Integration of Reinforcement Learning and Adaptive Robust Control

Shijie SU, Yongqin CHENG, Yi HU, Jianhui HE, Shuji YANG

2025, 36(10):  2335-2342.  DOI: 10.3969/j.issn.1004-132X.2025.10.022

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The dual-valve electrohydraulic servo systems， which employed a small-flow servo valve and a large-flow proportional valve to drive the same actuator in parallel， offered advantages such as low cost， high flow rate and high accuracy. However， the control performance of the systems was compromised by parameter uncertainties， system nonlinearities and disturbances. To address these issues， a dual-valve coordinated control strategy was proposed which integrates the SAC reinforcement learning algorithm with the ARC algorithm. This control strategy aimed to reduce transient errors generated by the proportional valves and the servo valves during work switching through a specifically designed flow allocation strategy. Additionally， the upper SAC algorithm learned the dynamic nonlinearities of the target electrohydraulic servo systems. Consequently， the control parameters of the lower ARC algorithm were dynamically adjusted， thereby enhancing the system's control performance and robustness.The findings of this study establish a solid theoretical foundation for subsequent simulation and experimental validation.

A Method for Packing Marble Slabs Based on Original Plate Sliding Strategy

Baosu GUO, Yongchun WANG, Jianming MA, Wancheng SUN, Shiyun WANG, Chuanzhen HUANG

2025, 36(10):  2343-2350.  DOI: 10.3969/j.issn.1004-132X.2025.10.023

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In order to solve the issues of cutting marble slabs and ensure consistent texture and color difference in the final rectangular panels while improving material utilization， a contour extraction algorithm was adopted to extract the contours of the usable areas on the original marble plate and a rectangle packing method was proposed based on an original plate sliding strategy. The lowest horizontal search algorithm under the guillotine constraint was used to construct the part domains and the ABWO algorithm， which integrates the artificial bee colony algorithm and the black widow optimization algorithm was introduced to optimize the part domains. By sliding and rotating the original plate within the part domains and using the utilization rate as an evaluation metric， an efficient solution for the optimal cutting scheme was achieved. The experimental results indicate that in the packing experiments with single size rectangular parts， the proposed method reduces the packing time by more than 90%， while achieving a filling rate comparable to traditional methods. The packing results meet the guillotine constraint， which is beneficial for subsequent cutting processes. In the experiments with non-single size rectangular parts， the implementation of the ABWO algorithm optimizes the order of parts placement， resulting in a 5% increase in the filling rate of the part domains. By combining part domains with the original plate sliding strategy， the final filling rate is improved by 3% compared to traditional packing methods.

Damage-quality State Mapping Model of Scrap Parts under Uncertain Service Environment

Hongfei GUO, Fang ZHONG, Yaping REN

2025, 36(10):  2351-2358.  DOI: 10.3969/j.issn.1004-132X.2025.10.024

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Given the uncertainty of the service environment， the quality assessment of scrap parts became more complex. A damage-based multi-state mapping model （DBMS） was proposed herein based on Dirichlet distribution. The model determined the main failure characteristics by analyzing the failure behaviors of the scrap parts， adopted multinomial distribution for mathematical abstraction of the damage data of parts， and selected Dirichlet distribution as the prior probability distribution. The posterior distribution parameters were updated by Bayes formula， and the posterior probability expected value of damage data mapped to different quality levels was obtained. Further， D-S evidence theory was introduced to integrate damage information to realize the comprehensive assessment of the quality of scrap parts. In order to verify the feasibility and effectiveness of the model， waste worm gear was taken as the case study object and compared with existing literature methods. The experimental results show that the model has advantages in prediction accuracy and generalization ability.

Design and Applications of Droplet-based Digital PCR Microfluidic Chip with Integrated Fluid and Temperature Control

Chunhua HE, Jinhui YAO, Lei NIE, Guanglan LIAO, Tielin SHI, Zhiyong LIU

2025, 36(10):  2359-2368.  DOI: 10.3969/j.issn.1004-132X.2025.10.025

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Digital PCR （dPCR） had emerged as a vital tool in molecular biology and clinical diagnostics due to the high sensitivity， accuracy， and absolute quantification capabilities. However， challenges had persisted regarding integration level， sample volume requirements and fluid control. An integrated droplet-based dPCR microfluidic chip incorporating a rapid valve system and automated heating system was presented， along with optimized fabrication processes herein. The results show that the chip may generate droplets efficiently and uniformly， with a maximum generation frequency of 5.132 kHz and a droplet diameter CV（the coefficient of variation） of only 1.67%. Rapid fluid control within 0.1s is enabled by the deformable valve， while temperature ramping rates of 1.2 ℃/s with temperature variations within ±0.6 ℃ are achieved by the integrated on-chip thermal cycling system. Fluid evaporation is effectively prevented by an improved PDMS formulation， and the accuracy of 99.7% is achieved by the droplet recognition algorithm.

Design and Optimization of Human-machine Compatibility of Knee-ankle Exoskeletons

Xinyao TANG, Rong YIN, Xupeng WANG, Jiayin YANG, Xiaoyi LIU, Yuyang HAO

2025, 36(10):  2369-2378.  DOI: 10.3969/j.issn.1004-132X.2025.10.026

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To address the challenges of poor compatibility in current exoskeletons and human legs， a knee-ankle exoskeleton was designed based on human-machine compatibility. The spatiotemporal data of lower limb joint movements were collected through a motion capture system. A four-bar mechanism with a J-shaped motion trajectory that might adapt to the instantaneous center of human knee joint movement was designed based on the physiological characteristics of knee joint rolling and sliding motions. A linkage mechanism optimization design method for simulating knee joint motions was proposed. The optimized four-bar mechanism was validated through numerical simulation to fit human motion well. The development of an power-assisted exoskeleton control system was achieved by combining angle sensors， and the effectiveness of the power-assisted exoskeleton performance was verified through gait and electromyography experiments. The experimental results show that the peak change in knee joint angle after wearing is less than 5%， the knee joint torque decreases， and the activity of muscles such as the lateral thigh muscle， gastrocnemius muscle， and biceps longus muscle decreases.

Modeling and Deformation Analysis of Dual Actuator Lung-like Soft Robots

Laixi ZHANG, Yanghaoyu ZHAO, Shengjie ZHU, Kaiwei MA, Fengyu XU

2025, 36(10):  2379-2388.  DOI: 10.3969/j.issn.1004-132X.2025.10.027

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To address the problems of extra radiation dose caused by image-guided radiotherapy， a dual-actuator lung-like soft robot inspired by the muscle hydrostatic structure of annelids was designed to simulate the respiratory deformation of human lungs in vitro. The 3D modeling and finite element simulation of the lung-like soft robots were carried out. The simulation results show that the axial actuator may increase the degree of deformability of the lung-like soft robots and makes it more inclined to the real lung deformability. The deformation characteristics of the lung-like soft robots were analyzed by means of conformal geometry. The deformation performance of the robots was tested by experiments. The results show that when the radial actuator pressure is as 1 kPa and 2 kPa and the axial actuator pressure is as 7 kPa， the z-axis elongation of the radial actuator is as 10.95% and 8.87%， respectively. The designed lung-like soft robots may meet the requirements of imitating lung deformation. Finally， the relationship between the deformation extent and the inflation pressure was obtained by linear fitting， which may be applied to the deformation control of the lung-like soft robots.

Laser-assisted Spinning Forming Laws of Ti/Al Bimetallic Thin-walled Parts

Zulong TAN, Jinchuan LONG, Junsong JIN, Xinyun WANG, Lei DENG, Xuefeng TANG, Fangtao CHAI

2025, 36(10):  2389-2396.  DOI: 10.3969/j.issn.1004-132X.2025.10.028

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To address the poor geometric accuracy and mechanics performance of Ti/Al bimetallic thin-walled conical parts formed at room temperature， a laser-assisted shear spinning process was proposed to enhance their performance. The temperature field at the deformation fronts was analyzed， and a time-varying model of laser power demand was established. Theoretical analysis demonstrated that stable control of the temperature field might be achieved by regulating the laser power growth curve. A finite element model was developed to investigate deformation behaviors and physical field distributions through simulation results. Experimental validation of the process was conducted. Findings indicate that during laser-assisted shear spinning， the stress transfer and strain distribution between the Ti and Al layers enhance interlayer coordinated deformation capability， resulting in favorable combinations of strength and plasticity in the formed parts. Compared with conventional room-temperature shear spinning and thermal spinning without laser heating， the laser-assisted approach significantly improves die-conforming accuracy and deformation uniformity of Ti/Al bimetallic parts， thereby optimizing their overall mechanics properties.

Development of Direct Flame Impingement Heating Processes and Control Technology for Continuous Annealing Units

Yonghui YANG, Ben QI, Haoyu WANG, Zhenhua BAI

2025, 36(10):  2397-2404.  DOI: 10.3969/j.issn.1004-132X.2025.10.029

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Based on flame direct impact heat flux model with Gaussian distribution， combined with characteristics of direct flame impingement heating burner， the arrangement of the burner and the position relationship with strip steel， the air burning compensation heat was applied to strip steel in a sidewall-like radiation， and the transverse line heat flow distribution model of the strip was established. According to this model， the influences of natural gas flow reduction changes of the edge burner on heat flow rate of transverse line of the strip were analyzed. With the optimization goal of the uniformity of the distribution of linear heat flow in width direction of the strip steels， the natural gas flow control technology of the burner at the edge of direct fire heating sections was developed. By applying this technology to production practice， the natural gas flow rate may be adjusted according to the optimal reduction factor， and the natural gas flow rate setting value suitable for the edge nozzle and the middle nozzle when the strip steels were heated with different widths may be obtained. Taking the typical widths of 1300 mm， 1100 mm and 900 mm as examples， when the flow rate of a single burner in the middle is as 12.6 m³/h， 12.1 m³/h and 11.8 m³/h， the optimal reduction coefficients are as 0.89， 0.78 and 0.65， respectively， and the flow rate of a single burner at the edge is as 11.21 m³/h， 9.44 m³/h and 7.67 m³/h， respectively. Thus， the strip steels in the furnace are evenly heated laterally， the temperature distributions of the strip steels in width direction meet the production demands， and the stability of the strip operation in direct fire heating furnace is greatly improved.

Ultrasonic Assisted Cutting Simulation and Validation Experimental Research Based on River Ice Mesostructure

Guojun DONG, Ruida LAI, Yong DAI, Zhiqing GUO, Mengwei WU

2025, 36(10):  2405-2412.  DOI: 10.3969/j.issn.1004-132X.2025.10.030

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Taking the Songhua River ices as the research objects， starting with the study of the mesostructure of river ices and combined with ultrasonic assisted cutting validation experiments， the effectiveness of ultrasonic-assisted ice cutting and the feasibility of improving production efficiency were analyzed. The simulation results indicate that ultrasonic assisted cutting may reduce the cutting force by approximately 38% when applied to the complex crystalline structure of natural river ices. Validation experiments demonstrates that this method enhances the feed rate and maintains the cutting quality of the ices， effectively preventing edge collapse and crack formation. In comparison to traditional cutting techniques， there is a significant improvement in both production quality and efficiency for river ices， thereby confirming the feasibility of employing ultrasonic assisted cutting for large-scale preparation of standard ice blocks.

Design and Experiment of Longitudinal Height-lateral Inclination Synergistic Profiling System for Combine Harvester Headers

Yi HUANG, Tao ZHOU, Zhihong ZHOU, Ziyu REN, Lin FU

2025, 36(10):  2413-2422.  DOI: 10.3969/j.issn.1004-132X.2025.10.031

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To improve the synergistic profiling capability of the combine harvester headers in terms of longitudinal height and lateral inclination， and enhance the detection sensitivity of the profiling devices， a synergistic profiling system for the headers was designed. The system consised of a curved-arm profiling detection device， a hydraulic system for header lifting and leveling， a PLC control unit， an HMI display and a manual control module. Through comparative analysis of the detection sensitivity and influencing factors of straight-arm and curved-arm profiling devices， the curved-arm profiling device with higher detection sensitivity was selected. A synergistic profiling control strategy for the headers was proposed， combined with an improved gray prediction variable-speed PID algorithm for the system control. Based on the relative parallel or inclined states between the header and the underlying terrain， independent or joint adjustment of the header heights and inclinations were achieved. Simulation results show that compared with the traditional PID control， the adjustment time of the profiling system is reduced by 58%， effectively improving the system response speed. Field tests indicate that at operating speeds of 4~10 km/h， the profiling system maintains high operation accuracy. The qualified rate of stubble height is increased by an average of 42.42% compared with the manual mode， and the absolute errors between the stubble heights of each group and the target heights are controlled within 15 mm， resulting in more uniform stubble. These results demonstrate that the profiling system has excellent synergistic profiling performance.

Development and Applications of Precision Heavy Duty Reducers for Double Rotating Shaft Mechanisms in Large Wind Tunnels

Yangyi XIAO, Yi ZHANG, Runyang SUN, Yongtao YIN, Shaojie PAN, Zhenhua ZHU

2025, 36(10):  2423-2432.  DOI: 10.3969/j.issn.1004-132X.2025.10.032

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In order to reduce the degree of blockage， strictly control the equipment size of a large-scale continuous transsonic wind tunnel double rotating shaft mechanisms， a small volume， high torque and high transmission accuracy reduction unit for heavy duty double rotating shaft mechanisms was developed. By comparing the common precision deceleration methods such as involute planet， cycloid-pin， harmonic and worm gears， the precision heavy duty transmission method of RV and NGW planetary reducer in series combination was put forward. Optimization design of the planetary reducer and strength analysis of key components were conducted based on ISO 6336， sequential quadratic programming algorithm， and finite element method. The return difference and transmission errors of the planetary transmission unit were calculated， and precision theoretical analysis of the reducers was performed. Among them， the processing and assembly of small backlash planetary transmission were the key technology， breaking through the precision machining of internal gear ring and planetary carrier， gear heat treatment deformation control and high-precision grinding， as well as the whole complex structure assembly adjustment technology. The dedicated test rig was developed to evaluate the transmission performances of the current precision heavy duty reducer， followed by validation in the wind tunnel， confirming that the manufactured reduction unit meets the requirements for applications in a large continuous transonic wind tunnel double rotating shaft mechanisms.

AMESim-PID-Kriging-based Reliability Analysis Method for Air-fuel Ratio Control of General Aviation Engines

Pengpeng ZHI, Xueqin LIU, Yi GUAN, Jiang WU, Zhonglai WANG

2025, 36(10):  2433-2443.  DOI: 10.3969/j.issn.1004-132X.2025.10.033

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To address the accuracy and efficiency challenges in the reliable control of air-fuel ratio for general aviation piston engines（GAPEs）， a reliability analysis method integrating AMESim-PID co-simulation and an adaptive Kriging model was proposed. A parameterized simulation model was established based on the AMESim platform according to the physical models of the intake， exhaust， and combustion systems of the GAPEs. Based on the oxygen excess coefficient a PID control model was presented to improve the accuracy of air-fuel ratio control by adjusting the injection pulse width. The GA-Halton sequence， adjust expected maximum function（AEMF）， and composite convergence criterion were proposed to establish a high-fidelity adaptive Kriging model to improve computational efficiency. A reliability analysis framework for air fuel ratio control was established based on AMESim-PID-Kriging， and the final failure probability was calculated by importance sampling（IS）. The case analysis shows that the proposed method may achieve high-fidelity modeling and accuracy control of the air-fuel ratio reliable control of the GAPEs， and accurately estimate the failure probability with fewer simulation times and solving time.

Design of a Dual-sided Equilibrium Clamping Device for Fuselage Docking Areas of Large Civil Aircrafts

Lei XU, Junshan HU, Zhilei FAN, Ende GE, Shengping ZHANG, Wei TIAN

2025, 36(10):  2444-2452.  DOI: 10.3969/j.issn.1004-132X.2025.10.034

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To enhance the assembly efficiency of the fuselage docking areas， an integrated assembly process of sealant extrusion and hole-making was proposed. The process was required to achieve balanced clamping of the docking areas， ensuring the uniform extrusion of the sealant and effectively suppressing the interlaminar gaps caused by hole machining. The typical working condition characteristics of a large civil aircraft fuselage docking areas were taken as an example， and a dual-sided equilibrium clamping device was designed. Using finite element simulation to quantify the unevenness of the interlaminar loads， combined with the minimum single-hole clamping force， the layout of the device's balanced pressing module and the main body materials were optimized. The balanced load tests of the device's docking areas and the integrated sealant squeezing and hole making verification were carried out. Results indicate that the balanced pressing module significantly enhances the uniformity of the clamping loads of the devices. Furthermore， when the hardness of the central rubber pressing ring is increased， the uniformity of the clamping loads is further improved. After selecting Q235 material， which offers better rigidity， for the main body of the devices， the minimum single-hole clamping force in the docking areas reaches 403 N， with an interval load unevenness of 1.4%. The sealant is extruded fully and evenly， and no significant burrs or rolled chips are formed between the layers.

Design and Control Strategy Research of PS Type Hybrid Power Systems for 100 Ton Double Bridge Rigid Mine Trucks

Huaqing ZHANG, Jiusheng BAO, Lei ZHANG, Deping HU, Xiao WEI, Yan YIN, Haohao XIE, Chenzhong ZHU, Jiao YANG

2025, 36(10):  2453-2462.  DOI: 10.3969/j.issn.1004-132X.2025.10.035

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Aiming at the problems of insufficient power and poor fuel economy in the traditional mechanical or series electric transmission systems of open-pit mine dump trucks， a PS hybrid power system and the deterministic rule power switching control strategy suitable for 100 ton double bridge rigid mining trucks were proposed. The PS type hybrid power mining truck joint simulation models were built by using MATLAB/Simulink and CRUISE software， and vehicle power and economy simulation tests were conducted. The results show that in both pure motor driving mode and diesel engine-motor hybrid mode， the maximum equivalent stress， equivalent elastic deformation， safety factor， etc. of the designed dual planetary gear transmission system are all within the allowable ranges of the materials and may meet the requirements of mechanical transmission structurally. The variation of meshing force between the sun gear， planetary gear， and ring gear shows a sinusoidal waveform in the time domain， which conforms to the variation law of planetary gear transmission. The amplitude changes uniformly in the frequency domain， which may meet the stable operation requirements of the transmission systems. The modified PS type hybrid mining truck has a maximum speed of 63 km/h， a maximum climbing slope of 32%， and a comprehensive fuel consumption of 288 L for uphill and downhill， which has increased by 26%， 60%， and 17.7% respectively compared to the original vehicle model.

Intelligent Vehicle Trajectory Planning Based on Spatio-temporal Risk Fields

Huifang KONG, Chenshun WANG, Qian ZHANG, Tiankuo LIU

2025, 36(10):  2463-2471.  DOI: 10.3969/j.issn.1004-132X.2025.10.036

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Aming to describe and avoid different dimensions of risks faced by intelligent vehicles， a two-layer trajectory planning method was proposed based on spatio-temporal risk fields. Traffic elements were divided into abstract elements and concrete elements， the spatial-temporal risk fields of abstract elements based on Gaussian distribution function and concrete elements based on spatial vector were established respectively to represent the environmental risks faced by intelligent vehicles in three dimensions： vertical， horizontal and temporal. Additionally， the trajectory planning problem of intelligent vehicles was divided into path and speed dual planning problem. The longitudinal-lateral dimension risk and longitudinal-temporal dimension risk were accordingly applied to dynamic planning cost function. Then， the path and speed with the comprehensive lowest cost were calculated， and combined with quadratic programming algorithm， the path and velocity were further optimized to obtain the final trajectory. Simulation results demonstrate that the proposed methodology may effectively characterize spatio-temporal driving risks across diverse scenarios while generating constraint-satisfying trajectories， thereby significantly enhance road driving safety.

Instantaneous Covalent Bonding Modification of Diamond Surfaces with Graphene

Bo YAN, Ni CHEN, Ning HE, Jiafeng SHE, Xianzi CHEN

2025, 36(10):  2472-2475.  DOI: 10.3969/j.issn.1004-132X.2025.10.037

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The paper focused on the high-performance requirements for diamond engineering surfaces in high-tech fields such as aerospace， micro-electro-mechanical systems， biomedicine， and nuclear energy. It addressed key challenges including the susceptibility of diamond to graphitization and amorphization under high loads and contact with ferrous metals， as well as the poor frictional behavior of conventional diamond surfaces. A novel concept of “in-situ instantaneous transformation” of diamond surfaces into graphene was proposed， along with the development of a laser induced-flywheel mechanical cleavage method. This method successfully stabilized a unique diamond-nano-graphite-graphene covalent structure in ambient conditions. Experimental results demonstrate that this new structure synergizes the excellent properties of diamond， graphite， and graphene. It offers a novel approach to resolving engineering bottlenecks associated with diamond applications and holds promise for opening up new avenues for the use of diamond， diamond coatings， graphene， and all-carbon devices in mechanical， electronic， aerospace， and other fields.