This PDF file contains the front matter associated with SPIE Proceedings Volume 13261, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

Taking the development of public computing service systems as the background requirement, combined with Digital Twin related technologies, the design of computing units is carried out. Research is carried out from the aspects of structural design, thermal simulation, mechanical simulation, and life cycle prediction, breaking through key technologies such as product health management technology based on Digital Twin ideas, thermal simulation, and twin technology based on model analysis, and mechanical simulation and twin technology based on finite element method. A full life cycle information mirror of computing units in public computing service systems is constructed to improve the reliability, maintainability, guarantee, and testability of computing units, laying a foundation for subsequent in-depth research.

Spineloxides with AB2O4 molecular formula units represent a promising sensing material. The metal-organic frameworks (MOFS) were adopted as the template, with a simple one-step solvothermal method and annealing, ZnO/ZnCo2O4 core-shell nanospheres were synthesized, and Ag particles were doped on its surface through a deposition process. The samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The response of the Ag- ZnO/ZnCo2O4 material to 100 ppm methanol gas was higher than that of the ZnO/ZnCo2O4 material, and the modification of surface Ag particles could improve the gas sensitivity of ZnO/ZnCo2O4 core-shell nanospheres’ sensitivity.

In this study, bisphenol A epoxy resin (DGEBA) was used as the resin matrix, methyl tetrahydrophthalic anhydride (MTHPA) as the curing agent, phenol as the promoter, and boron nitride as the filler. The variation characteristics of the viscosity and thermal diffusivity of the epoxy anhydride system after introducing boron nitride filler were studied by viscometer and laser thermal conductivity meter. The relationship between the viscosity and temperature of the epoxy anhydride system after adding 0%, 1%, 2%, and 5% concentration of boron nitride filler was analyzed during the curing process, and the relationship between the thermal diffusivity and temperature after adding 1%, 2%, and 5% concentration of boron nitride filler. The results show that the viscosity increases with the increase of boron nitride concentration, and the thermal diffusivity increases with the increase of boron nitride concentration. When adding 2% concentration of boron nitride, the viscosity is relatively low and the thermal diffusivity is relatively large. This provides a reference for developing epoxy resin composites with low viscosity and high thermal conductivity in dry transformers.

In response to the requirements for equivalent testing of the expansion of stator coils in permanent magnet traction motors, an alternative method for calculating the dimensions and loading conditions of equivalent specimens is proposed. Numerical simulation analysis is conducted on the bending forming process of both the stator coil and the equivalent specimen. Based on the Ramberg-Osgood model, an elastic-plastic equivalent strain ratio coefficient (λ) is introduced to describe the proportion of forming elastoplasticity to the total strain. The results indicate that the mean deviation of λ for the two corresponding forming methods is 2.03%, with a maximum deviation not exceeding 8.05%. By comparing the springback values of the actual produced stator coils with the numerical simulation results of the equivalent specimens, the feasibility of the elastoplastic theory and the validity of the equivalent model are verified.

To solve the problem of insufficient utilization of equipment and low production efficiency of the fuselage production line of certain aircraft program, this article analyzes and studies the fuselage assembly process and assembly station cycle, establishes the geometric model and logic simulation model for the production line by means of the discrete event simulation software Plant simulation to simulate the assembly of large components and find out the bottleneck restricting production capacity increase in the assembly process. The simulation results have been applied to optimize the takt time and operation process of fuselage assembly line, with a set of production line improvement plan generated, which realizes the resource balance and capacity increase of the production line.

This article conducts parameter matching and simulation analysis on a DCT pure electric car based on Cruise software. First, the car parameters and design requirements of the studied vehicle model are introduced. Then, the power system parameter matching and vehicle parameter matching process of pure electric vehicles are explained in detail, including the matching of motors, batteries, and DCT transmissions. Then, the application and advantages of Cruise software in parameter matching and simulation analysis of pure electric vehicles were introduced, and a simulation model of pure electric vehicles was established using Cruise software. Through simulation analysis, data on the vehicle's power and economy were obtained and compared with the design requirements. Finally, the parameter matching scheme was determined, which provided strong support for the design and optimization of DCT pure electric vehicles. This research not only helps to improve the performance and competitiveness of pure electric vehicles, but also provides useful reference and reference for subsequent research.

Aiming at the construction difficulty in the installation of main equipment of primary loop for high temperature gas-cooled reactor demonstration power station, this paper carried out design and application research of main equipment adjustment device. Through the principle of combining hydraulic lifting with jacking, the overall scheme is compared and selected, the design principle is determined, the design scheme is completed, and the lifting load and operation accuracy requirements for adjustment of the heavy pressure vessel cylinder, the metallic reactor core casing and the steam generator are meet. The results of the thesis have been applied to high-temperature gas-cooled reactor demonstration power station, solving the need for precise adjustment of primary equipment of the high-temperature gas-cooled reactor demonstration power station, and provides ideas and application experience for adjustment of heavy equipment in other nuclear power plants.

With the continuous improvement of radar operational efficiency requirements, mobility has become an increasingly important factor in radar design, and radar mobility is closely related to radar removal efficiency. Based on the logical and complex characteristics of the radar erection and withdrawal process, this article uses a user experience map as a process analysis tool. By analyzing elements such as user behavior paths, touch points, user expectations, and goals, product pain points and innovation opportunities are extracted, which guide the optimization design of radar erection and withdrawal and achieve effective improvement of radar mobility.

PID (Proportional Integral Derivative) control, as a classical control method, is widely used in petrochemical, metal smelting, food production and other industrial fields due to its superior control performance. With the continuous improvement of industrial production process, the process control environment is becoming more and more complex, and the controlled object often has complex characteristics such as multivariate coupling, large time lag, nonlinearity, multifactor interference, etc. Therefore, the research of PID parameter tuning method has been paid more and more attention, and it has become an important research topic in the field of automatic control. This paper reviews and analyzes Z-N empirical formula method, Critical Ratio method, Cohen-Coon method, ISTE method, fuzzy algorithm and adaptive particle swarm optimization (APSO) algorithm several PID parameter tuning methods, and applies the MATLAB software to analyze the effect of different tuning methods on the performance of the system through the simulation of Simulink comparison experiments. In this paper, the second-order system is used as the control object, and the experimental results show that the APSO PID parameter self-tuning is better than the other methods in the experiments of response performance analysis, tracking performance analysis, and robustness analysis in terms of rise time, overshooting amount, stabilization time and robustness, all of them are better than the other methods.

The oil tanker is composed of double shell and single main deck, so the local high stress problem at the joint of deck longitudinals and transverse bulkhead is obvious, which is a threat to hull safety. In order to realize lightweighting design and satisfy the structural safety assessment as well, theoretical calculation, cargo hold structural strength analysis and local structural strength analysis were carried out. Optimized design method of permanent means of access (PMA) structure was provided in this paper. The discontinuous PMA does not participate in the deformation of transverse bulkhead, so its own weight is lighter and there is no stress concentration problem of itself. Continuous PMA participates in the deformation of transverse bulkhead, which can reduce the maximum stress by 42.5% of deck longitudinals and reduce 180 tons of structural weight in the cargo hold area. But there is a problem of stress concentration in the structure itself, which needs to be paid attention to in the progress of design. This paper can provide reference for design of other similar structures.

The light-weight design of prosthetic knee joints can provide a freer and more comfortable life for individuals who have lost their limbs. In this paper, the anterior linkage rod of prosthetic knee joint was taken as the research object. Through the comparison and analysis of various structural optimization methods, the light-weight design of prosthetic limb was realized under the condition of meeting the actual safety and performance requirements. Based on Altair Inspire, the optimal light-weight scheme of "two-way mold pulling + symmetry" was obtained through the comparative analysis of five shape control methods, which was verified by geometrical reconstruction and kinematic simulation. The results show that: the mass of the front linkage rod after optimization becomes 13.53*10^-3Kg, which is reduced by 61.29%, and light-weight and reduced manufacturing cost are realized. The minimum safety factor is 3.0, which meets the design requirements; the maximum displacement is 13.68*10^-3mm, with negligible deformation; the maximum Mises equivalent force is 76.67MPa, which is 72.60% higher, which improves the load-bearing capacity of the part and prolongs the service life of the part; and the optimal solution is further applied to the PEEK material, which obtains a better light-weight performance. This study provides structural design and material selection reference for the subsequent light-weight manufacturing of other parts and overall structure of prosthetic knee joints.

Taking the mechanical equipment in the stone processing industry in southern Fujian as an example, this paper solves the practical problems such as the deformation of the outer protective devices caused by extreme working conditions of mechanical equipment. This article proposes several design schemes for large-area and load-bearing sheet metal parts, and applies simulation analysis method to study the deformation variables of each scheme. The result shows that the deformation problem of the outer protective device of the stone processing equipment has been solved in this optimization plan, which can provide reference for the improvement of similar products.

The research aims at secondary conditioning cylinders that suffer high-frequency manual intervention and lagged adjustment in tobacco threshing and redrying. In the case of the secondary conditioning cylinders processing the ACDFAPK, DBBFAH, and DCAKAHK Tobacco Modules (2021 Season) in the Yunnan Chuxiong Tobacco Redrying Factory, it takes the equipment parameters and the processing environment’s temperature and moisture as the test data and considers the correlations as the evaluation indexes, so as to analyze the relationships between the equipment parameters given by the experts and the environment temperature and moisture. The prediction model for experts’ set values of hot air temperature is built by virtue of the deep neural network (DNN) machine learning (ML) algorithm. The results show that: (1) the primary parameter requiring adjustment based on the environment temperature and moisture is hot air temperature; (2) the prediction model for experts’ set values based on the DNN algorithm has a mean square error (MSE) of 5.745, a coefficient of determination (R-square) of 0.66, and a prediction accuracy of 98.49%. Thus, this prediction model boasts favorable fitting performance, small prediction errors, and high prediction accuracy.

A two-stage reducer structure for AGV is proposed. The finite element simulation analysis of the transmission part of the reducer is carried out by Ansys Workbench, and the stress and strain distribution of the key parts of the reducer is obtained. Adams software was used to conduct dynamic simulation calculation for the virtual prototype to verify the dynamic performance of the whole machine. Based on the load spectrum of finite element simulation analysis, fatigue life simulation of the finite element model of the reducer was carried out by Ncode DesignLife fatigue analysis software, and life cloud and damage cloud map of key components were obtained. The results show that the life prediction of the AGV reducer meets the requirements of the design index, and provides ideas for the optimization design and acceleration life design of the reducer.

With the expansion of equipment scale and the improvement of installation accuracy, the conventional installation method of large-scale lithium-ion copper foil industrial park is difficult to meet the needs of development, resulting in poor installation effect. Therefore, this paper proposes a method of fine-tuning large-scale lithium-ion copper foil industrial park equipment by combining BIM and false axis method. According to the pipeline arrangement, BIM model is constructed; The characteristics of influencing factors of installation and maintenance are calculated, normalized, the weights of installation and maintenance factors are reasonably distributed, the consistent inspection values are analyzed, the factors of equipment installation and maintenance in large-scale lithium-ion copper foil industrial park are determined, and the installation steps are designed to realize the equipment installation in large-scale lithium-ion copper foil industrial park. The experimental results show that the installation and equipment maintenance time of this method is short, the failure times of all kinds of equipment are zero, and the installation deviation distance is below 0.1cm, which has high stability and accuracy.

As the basic equipment of manufacturing industry, the development level of machine tools marks the development status of the country. Therefore, to study the composition structure of small three-axis CNC milling machine, design the overall structural framework of the CNC milling machine, determine the whole program of the milling machine, construct the skeleton multilevel structural model of the milling machine, and modularize the structure of the milling machine by analyzing the milling machine spindle, axial drive mechanism, the base and other key components; ABAQUS finite element simulation software is used to analyze the static and dynamic characteristics of the main stress components, static simulation results show that the vertical frame, support frame deformation were 2.464×10^-3mm, 4.096×10^-5mm, deformation is small, in line with the design requirements; modal analysis results show that the vertical frame, the support frame of the first six orders of the intrinsic frequency is small, through the increase of the support structure, change the material of the components and other ways of structural optimization, will be expanded by about 10 times the intrinsic frequency; finally, Completed the milling processing experiment, verified the reliability of the milling machine structure, proved the accuracy of the modular design of the milling machine structure.

A numerical simulation study is carried out to investigate the influence of bolt tightening process on the distribution of bolt preload force and deformation of linear guide assembly. Firstly, the basic principle of elastic interaction of bolt groups is described and a mathematical characterization model is established. Secondly, the influence of bolt tightening order is analyzed, and it is found that the cross-tightening result is better than the sequential tightening. Finally, the step-by- step tightening strategy of bolts is studied, and the influence of different tightening volume allocation schemes on the residual preload force of bolts and the deformation of the guide rail assembly is analyzed through simulation and comparison of different tightening volume allocation schemes under two-step cross-tightening. The results show that when the guide rail bolts are tightened by two-step cross-tightening and the first step tightening amount is 70%, the consistency of the bolt residual preload is the best, and the maximum deformation of the guide rail is the smallest.

To meet the demand of 19in radio frequency instruments for high reliability chassis, the chassis structure design and manufacturing was carried out focusing on the chassis components, mainly including chassis structure design, semi-rigid cable module design, metal parts processing, semi-rigid cable module processing and chassis assembly. The final equipment passed the environmental adaptability test assessment, and its performance met the requirements for the use of the four-level equipment in GJB3947A-2009. demonstrates the feasibility of the chassis structure design and manufacturing, and providing a reference for the design and manufacturing of the same type of 19in radio frequency chassis.

Addressing the issue of positional errors in key load-bearing components such as crankshaft, cycloidal wheel, and pin gear housing during machining and manufacturing, which reduce the transmission accuracy and smoothness of RV reducers, this paper proposes methods for adjusting positional errors and allocating positional tolerances. Firstly, using the BX40E reducer as a study object, an error transmission chain is constructed to illustrate the error transmission path of RV reducers. Secondly, a state-space model for the error transmission process is established. Then, combining optimal control theory and considering factors such as transmission accuracy, adjustment labor costs, and measurement uncertainty, optimal adjustment amounts for each assembly step and the final error state are provided. Subsequently, a genetic algorithm was employed to allocate positional tolerances for critical components to minimize the overall manufacturing cost. Simulation results demonstrate that the transmission error decreases by approximately 40% when the precision weight Q ranges from 0 to 5, and by about 15% when Q ranges from 5 to 10. The proposed method proves effective in enhancing the transmission accuracy and stability of the RV reducer, but it is recommended to select different precision weights based on actual accuracy requirements to minimize costs.

Pentamode materials (PM) is a representative type of metamaterial capable of adjusting equivalent mechanical properties by tailoring its microstructure. Generally, there exists a significant correlation between its density (ρ) and compression modulus (E), which hinders meeting the needs of extreme mechanical cases, such as ultralight high-strength material and transformation acoustics. In this paper, an in-depth mechanical analysis by Timoshenko beam theory was conducted and an analytical expression was derived to intuitively capture the essence of the linkage between PM’s equivalent medium properties and geometric parameters. By this analytical equation, we theoretically proved an intrinsic decoupling relationship between the compression modulus and density. Based on it, we proposed a new microstructure configuration that can achieve perfect decoupling of compression modulus and density, as well as flexible adjustment of density and acoustic impedance over a large range can be implemented easily. Our results can support the developing of pentamode metamaterials with extreme-performing, further bolstering the versatility in shaping underwater acoustic waves.

The cleaning of high-rise buildings' glass curtain walls and windows is a challenging and risky task. The utilisation of intelligent cleaning robots can effectively address the hazardous task of high-altitude glass cleaning, thereby replacing the traditional manual cleaning approach. This paper presents a design for an intelligent robot with a double-disc twisting and rubbing, negative pressure adsorption and fogging dissolving structure. This robot is capable of achieving efficient and intelligent cleaning of glass through the worm gear and planetary wheel coordinated transmission, and the pressure sensor is used to adjust the friction force. The woolen cloth support frame was subjected to a static analysis using the SolidWorks module, and the results demonstrated that the designed structure met the specified requirements. The robot with the advantages of simple structure and low cost, which can provide a new idea for glass cleaning industry and cleaning robot industry related structural design.

Reviews of current supercapacitor characteristics, synthesis methods of electrode materials, and NbC electrode materials are presented. And a new solution is proposed for how to solve the method of obtaining Nb in electrode materials. A new material to extract niobium resources with coke as a matrix, through the in situ synthesis of polyaniline in the pores of coke prepared polyaniline/coke composite materials, which will be used for the extraction of niobium resources from the leach solution of Bayan Obo tailings, not only efficiently extracted niobium resources but also solved the problem of environmental protection.

This study aims to develop a nonlinear viscoelastic model for the anti-vibration (AV) glove. The developed AV glove model will be coupled with a human hand-arm model to predict the vibration transmission from the hand-held tool to the hand-arm system with and without an AV glove. Five AV gloves were selected, namely, Air1, Air2, Gel1, Gel2, and Hybrid. An experiment was designed to measure the force-deflection and force-velocity characteristics of each AV glove at 20Hz and 30Hz. The experimental data were used to identify the parameters of the glove models as a target function. A nonlinear viscoelastic model of each AV glove was developed based on the Bouc-Wen model. The particle swarm optimization (PSO) algorithm was used to determine the parameters of each AV glove model. The results show that R² values are over 0.9, signifying a strong fit of the developed model to experimental data. This study demonstrates that the proposed model can effectively predict the performance of AV gloves, which can be used to couple with the hand-arm system and to further study the effectiveness of AV gloves on vibration isolation from tools to the human hand-arm under different work conditions.

The sequence in which the clamps are applied has a significant influence on the location error and dimensional variability for non-rigid parts assembly. This paper presents a novel clamping sequence optimization methodology applicable for deformed parts assembly with the main objective of minimizing the part-to-part gap. The methodology combines finite element modelling and genetic algorithm to realize the generation of an optimal clamping sequence for compliant parts. Finite element models are developed to simulate the transformation of geometry under the constraints of clamps and the computation of part-to-part gaps is achieved by updating the geometry along the clamping sequences. A genetic algorithm is applied to automatically search for the optimal clamping sequence. In the genetic algorithm, a coarse mesh is used to solve the time-consuming problem and a fine mesh is used to test the results. The methodology is demonstrated and validated using the results of a case study, which obtains an accurate part-to-part gap with a 90% reduction in computation time to identify the optimal clamping sequence.

Deployable antenna mechanism has a rapidly growing demand in the space field, but most of the existing mechanisms are based on the classical configuration, and there is a lack of systematic configuration innovation design method. Based on the thought of developing mechanism derived from stable structure and the principle of surface formation, a configuration method of deployable surface supporting mechanism based on curve supporting mechanism is proposed. Firstly, based on graph theory, the configuration method of supported stable truss structure is established. Combining with the folding and deployable geometric constraints, the truss members is replaced by folding members, and the mechanism configuration based on stable truss structure is realized. Finally, the isomorphic configurations are eliminated by the correlation degree code method, and a series of curve support mechanism configurations are obtained. The formation method of the research extends the application of mechanism graph theory, and provides a new way for the configuration innovation of satellite antenna mechanism.

In order to investigate the effects of different cathode diameters and electrolyte concentrations on the efficiency and surface morphology of electrochemical finishing, we used finite element analysis software for simulation to explore the trend of changes in removal amount under different cathode diameters and electrolyte concentrations. Meanwhile, the effects of different electrolyte concentrations and cathode diameters on machining efficiency were compared through experiments. The research results indicate that as the cathode diameter and electrolyte concentration increase, the removal amount also increases. After electrochemical finishing, the values of surface micro high and micro low points were reduced from 40.64 μm to 27.33 μm. The original "peak" shape in the microstructure was flattened into a "circular arc" shape, significantly improving the precision machining effect. This research result indicates that by appropriately adjusting parameters such as cathode diameter and electrolyte concentration, the removal amount and surface quality of electrochemical finishing can be effectively controlled, providing an excellent solution for precision machining of metal parts.

The fast steering mirror system (FSM) is a high-performance optical device, and the mechanical characteristics of its supporting structure directly affect the system's response speed and closed-loop bandwidth. The paper designs a two-axis flexure support structure based on an elliptical-hyperbolic hybrid flexure hinge, some working requirements of the flexible support structure are clarified. The mathematical model of the two-axis rotational stiffness of a flexure support structure is developed. In response to the resonance frequency requirements of the FSM system, the primary structural parameters of the flexure hinges are selected. Finally, the modal analysis of the system is conducted using finite element software. The analysis results demonstrate that the simulated resonance frequencies of the FSM system in two working directions have a relative error of less than 5% compared to the theoretical calculation results, validating the rationality of the chosen parameters for the flexure hinge structure.

The lunar polar regions are rich in resources, particularly the water resources that are urgently needed for the establishment of a lunar research station. One of the Chang'e 7 missions is utilize a drilling sampling method to collect in-situ ice-soil samples, the heat generated during drilling can cause the water-ice in the ice-soil to sublimate, seriously affecting the in-situ nature of the drilling and sampling. Therefore, this paper considers the lunar soil as a continuous ice-covered ice-soil mixture structure, provides a numerical calculation methods for water-ice sublimation and heat absorption, simulates the drilling sampling process by the discrete element method, and obtains the water-ice volatilization and the drilling temperature rise information during the sampling process, and to establish a discrete element simulation system for the ice-soil drilling. The reliability of simulation model is verified by comparing the experimental and simulation results of ice soil drilling. The drilling simulation of ice-soil particles with 5% moisture content is carried out in article, and the results of temperature rise and moisture content of ice-soil drilling under the consideration of water-ice sublimation are investigated. The results of the study indicate that, in the drilling time of 120s, the temperature rise of ice-soil samples with the consideration of water-ice sublimation is lower than that of ice-soil samples without the consideration of water-ice sublimation by 4°C, and the moisture content is reduced to 4.873%, and the rate of water loss is about 2.54%, and the moon soil drilling and mining information is more accurate and has theoretical guidance for drilling high-fidelity samples.

The material's absorption capacity can be accurately determined using a key parameter known as the absorption coefficient. However, existing techniques for measuring the absorption coefficient, such as the impedance tube and reverberation methods, have been found to have certain drawbacks, as this study has identified. In this context, the study of the phase of the sound pressure, which is determined by a pair of microphones placed at the same distances, is presented. There is a lag in obtaining the absorption coefficient at the leading edge of the absorption material. In the end, a detailed examination is carried out on a particular absorbing material, with the sound absorption coefficient derived from this technique aligning closely with the outcomes of the impedance tube approach and reverberation room technique, particularly at low frequencies of sound. In reference to a case study on the distribution of radiated energy noise from automotive engines, the measurement of absorption coefficients based on time delay is faster, as evidenced by the aforementioned method, which empirically demonstrates the effectiveness and feasibility of the proposed theory.

This article mainly focuses on the study of how to reduce the empty head rate of cigarettes in the production process of cigarettes. At present, almost all needle roller components in cigarette systems are driven by DC closed-loop speed regulation, and their speed is controlled by DC voltage, which directly affects the structure and quality of cut tobacco, thereby affecting the degree of cut tobacco falling, i.e. the empty head rate. The system has not yet achieved automatic matching of needle roller speed with different tobacco cutting structures, resulting in fluctuations in empty head rate. The aim of this study is to address this issue by first establishing a regression equation for the structure of tobacco and achieving automatic calculation of the structural coefficients of tobacco; Secondly, with the cigarette empty head rate as the control objective, a regression fitting model for the structural coefficient of tobacco and the needle roller voltage is established, and it is integrated into the control system to achieve automatic adjustment of the needle roller speed. The experimental results indicate that the average empty head rate of each cigarette brand decreased from 0.26% to 0.16%. The method proposed in this study demonstrates significant potential for both promotion and practical application.

High pressure water jet has broken through a series of negative impacts such as noise and dust caused by traditional mechanical crushing equipment in the impact crushing of concrete, and has advantages such as high efficiency, economy, and environmental protection. However, in practical engineering applications, it is an urgent need to choose appropriate dismantling parameters to reduce dismantling costs and improve dismantling efficiency. Based on this, this article takes the Bernoulli equation as the theoretical basis to analyze the process of high-pressure water jet breaking concrete, and provides the theoretical values of nozzle outlet velocity and spray flow rate; And the influence of breaking parameters such as jet pressure, target distance, and nozzle lateral velocity on breaking depth was studied in the experiment. The results show that as the jet pressure increases, the depth of water jet breaking increases approximately linearly, indicating that a higher jet pressure is more conducive to water jet breaking; As the target distance increases, the breaking depth first increases and then decreases. When the jet target distance is 60mm, the breaking depth reaches the maximum value of 76mm; The depth of concrete breaking is inversely proportional to the lateral velocity of the nozzle. As the lateral velocity of the nozzle increases, the depth of breaking gradually decreases. When the lateral velocity reaches 60mm/s, the rate of attenuation gradually decreases. The research results provide data guidance for selecting reasonable demolition parameters in the actual demolition process of engineering.

In order to solve the problems of indoor mobile robot mapping, such as not detecting small obstacles or unsatisfactory mapping results, this paper proposes a depth camera and LiDAR fusion method for indoor mobile robot mapping. First, the LIDAR odometer was estimated using LIDAR distance scanning. Then the LIDAR odometer, wheeled odometer, and IMU are fused using Kalman filtering to improve the odometer accuracy. Next, the depth image is converted to pseudo-laser information, and the pseudo-laser information and laser information are simply spliced, weighted average and other operations are performed to fuse them into laser information with more comprehensive information. Finally, the mapping algorithm is used to receive the fused laser information and the fused odometer to complete the 2D construction of the surrounding environment. The Gazebo simulation environment and the robot model are built through the ROS2 system for verification. The research results show that the optimized fusion algorithm makes the indoor mobile robot clearer in the mapping of hollow-out objects, more accurate in obstacle, and more accurate in robot. This provides a certain reference for mobile robot map.

In order to reduce the energy loss in the process of turning titanium alloy TC4 and realize the purpose of reducing the processing cost and saving energy, the YG6X tool was selected and the turning simulation model was established in ABAQUS software. The rule and degree of influence of cutting parameters on cutting force during turning were studied by single factor test and orthogonal test. The regression model of cutting force is established in SPSS software, and the parameters of the three elements of cutting parameters are optimized in MATLAB software with the minimum cutting heat as the optimization objective. Finally, the optimal cutting parameters with the minimum cutting heat are obtained as cutting speed Vc=39.04m·min^-1, feed rate f=0.08mm·r^-1, cutting depth ap=0.15mm, which can effectively reduce the energy loss in the process of YG6X tool turning TC4.

This study addresses the phenomenon of nozzle clogging during the printing process of PEEK material. The optimization objective is the relatively short transition zone length of the nozzle temperature distribution. The research involves the optimization design of a PEEK material 3D printing nozzle. Utilizing range analysis, the study investigates the impact of nozzle structure under different parameter levels on the transition zone length. The optimal nozzle structure parameters are determined as follows: fin thickness of 1mm, fin diameter of 22mm, nozzle diameter of 0.4mm, and heating zone length of 20mm. The optimized transition zone length is reduced by 11% compared to the initial design. Finally, a multivariate regression prediction model is established for the transition zone length and its influencing factors, and the accuracy of the model is validated.

Aiming to address the issues of low positioning accuracy and high waste of spray application robots in China's facility agriculture, a robot capable of imitating manual spraying behavior is highly needed to enhance spraying precision and reduce pesticide waste. We have designed a robot equipped with a mechanical arm that can move up and down for spraying, aiming to achieve imitation of manual up-and-down spraying for facility-grown tomatoes and cucumbers. The robot is modeled in 3D using SW software. The kinematic equations of the actuator arm are established using the DH method, and the forward and inverse kinematics are analyzed numerically. MATLAB was employed for simulation purposes, and the Monte Carlo method was utilized to generate the workspace diagram, which demonstrated that the maximum workspace of the actuator arm in the vertical direction was 0.8 m. By integrating the joint space and Cartesian space trajectory planning method, the trajectory curves of the actuator arm were obtained in the simulation. The simulation results yielded the angular displacement, angular velocity, angular acceleration, and angular change curves for each joint, which further substantiated the rationality of the design by demonstrating the continuous and moderate nature of the curves' change. The continuous and gradual evolution of the curves serves to reinforce the rationale behind the design. The design is further validated by the continuous and gradual evolution of the curves. It provides a reference point for the construction of automated spraying robots.

Compared to strong alkali activating agents (KOH, NaOH), transition metal salts as activating agents could neither corrode equipment nor pose a danger to operators. However, the surface area of the carbon materials carbonized by transition metal salts is lower than that activated by alkali activating agents. And the specific surface area of the carbon materials is related with electrochemical performance of supercapacitor. Thus, transition different metal salts are as the activating agents to activate the ZIF-8 to obtain the high specific surface area carbon. In addition, the effect of the amount of Zn(NO₃)₂ impregnation on the the final specific surface area and the electrochemical properties of these activated carbons in a 6 M KOH electrolyte are investigated in depth. The large specific surface area activated carbon have been obtained after calcination under 1000ºC with using ZIF-8 as the precursor and transition metal salts as the activating agents. The Zn(NO₃)₂ of lower boiling point and easy reduction as the activating agent, the specific surface area can reach up to 1700 m²·g^-1. And the specific capacitance is up to 197.5 F·g^-1 and energy density is 6.9 Wh·kg^-1 at 125 W·kg^-1 in 6 KOH electrolyte.

In view of the low production efficiency and poor working environment of tuna by manual slicing, an intelligent constant weight slicer for tuna based on machine vision was designed. The overall structure of the slicer is introduced, which is mainly composed of three parts: image acquisition and processing system, cutter device and control system, which realizes the overall automatic operation of the slicer. Focusing on the analysis of the cutter device in the tuna slicer, the model of the straight edge cutter was established by UG, and the static and modal analysis of ANSYS was carried out, and the maximum frequency of the straight edge cutter was 2130.9Hz, the stress was 7.698 MPa, and the maximum deformation was 2.727e-004 mm. Its slicing effect is good and efficient, which provides a basis for efficient constant weight slicing of tuna.

This paper investigates the vibration problem of a satellite controller bracket that is subjected to random excitation. We developed a parametric model for the bracket’s structure and optimized its dimensions using Abaqus random vibration analysis and Isight optimization algorithm. The optimized structure underwent bearing capacity analysis and random vibration analysis. On the premise that the structure satisfies the strength, stiffness, and frequency conditions, the power amplification factor is reduced and the structural mass is minimised, which effectively improves the vibration damping performance, leading to a more rational structural design.

The micro-leakage internal spherical detector is a new type of pipeline leakage detection method whose movement in the pipeline is essential for its design. This paper uses the numerical simulation method to analyze the detector’s dynamics. The motion of the spherical detector in the horizontal liquid transport pipeline is simulated for the liquid with different viscosity. The result shows that the detector is mainly in a rolling state during the movement, and its angular velocity has periodic fluctuations. Through this simulation, the movement mode of the spherical detector is obtained, which provides help for the subsequent design of the micro-leakage internal spherical detector.

The shedding of ice from transmission lines can lead to intense vibrations in conductors, posing severe threats to the entire transmission system. This is especially detrimental to the fitting strings of transmission conductors. In order to investigate the impact of ice shedding from transmission lines on the fitting strings, a study was undertaken with the 420kN disc-type suspension insulator tension string with three units and double suspension points and 210kN single-unit tension string for ground wires from a specific transmission line as the subject. The test plan entitled “Tests on Dynamic Properties of Typical UHVDC Tension Strings” was designed for this purpose. The tension connecting plates within the two tension fitting string sets were tested separately under scaled-down conditions to yield their stress load status. Subsequently, the test results underwent validation using the finite element method, which revealed a robust correlation between test and finite element results, and notable stress concentration within the tension connecting plate. A finite element analysis was then executed on the two full-sized fitting string sets under hazardous conditions, and the stress results were found to both meet the material’s strength limit requirements. These tests serve as the reference for the mechanical properties of fitting strings during the process of ice shedding from transmission lines.

With the help of molecular dynamics simulation, the model of monocrystalline Si workpiece and diamond indenter was established at the micro and nano scale, and the nanoindentation simulation at different temperatures was carried out to obtain the load displacement curve (P-h) at different temperatures, and then the influence of temperature change from 10k to 300K on the performance of silicon was explored. It is found that the lower the temperature, the higher the corresponding P-h curve, and the farther away from the origin is the intersection point of the unloading part of the P-h curve from the X-axis. At higher temperatures, the atomic spacing increases, and the atomic interaction force inside the Si is small, resulting in a small elastic recovery of the material, which ultimately makes the plastic indentation depth of Si.

The high density fiberboard(HDF) was processed using cemented carbide cutters on a CNC engraving and milling machine. An empirical model for wear on the rake face of the cutter and a binary nonlinear regression model for milling force were established, allowing analysis of the effects of spindle speed n, feed speed v, and axial milling depth a_p on the maximum width of wear on the rake face and milling force. The results indicate that spindle speed, feed speed, and axial milling depth are positively correlated with the maximum width of wear on the rake face, with the order of influence being n>v>a_p. Additionally, an increase in feed speed and axial milling depth leads to an increase in milling force, where the order of influence is v>a_p. Specifically, when the axial milling depth is 3mm and the feed speed is either 1500r/min or 2000r/min, the milling force exhibits a downward trend as the spindle speed increases. However, when the feed speed is reduced to 1000r/min, the milling force initially decreases and then subsequently increases with an increase in spindle speed.

Using MATLAB and ADAMS software, this study establishes dynamic simulation diagrams for the six-bar mechanism of a bullhead planer. Considering the impact of various physical quantities on the main cutting motion, output curves between the main cutting motion and each physical quantity are established. The main cutting motion structure utilizes a gear-linkage combination mechanism for transmission. The positions, velocities, and accelerations of the components in the six-bar mechanism's motion process significantly influence the operational efficiency and stability of the bullhead planer. Kinematic modeling, simulation output, and analysis of the bullhead planer's six-bar mechanism provide valuable insights for addressing inefficiency and inadequate design issues in planer design.

Stiffened composite panels are widely used in aerospace applications as primary load-bearing components. However, internal laminar defects in these panels can severely impact their mechanical properties. This study investigated the compressive failure mechanism of orthotropic grid-stiffened composite plates. To explore the impact of node interface delamination defects on macroscopic deformation behavior and failure modes, in-plane compression tests were conducted on four typical components. This was followed by an analysis of the macro-microscopic failure morphology of the composites. The results indicated that the failure mode of the stiffened panel plays a crucial role in its ultimate load-carrying capacity. Interface delamination defects at cross nodes had a minimal effect on the load-carrying capacity of small-sized local specimens, leaving their deformation and failure modes unchanged. Yet, these defects significantly compromised the local stiffness and failure modes of large-sized stiffened panels, causing a transition from compression failure to global buckling and local shear failure. Compared to defect-free components, the strength and stiffness decreased by 59.2% and 38.6%, respectively. These results offer valuable insights for the initial design, strength assessment, and damage tolerance design of such stiffened plates.

This paper investigates and summarizes the sensitivity analysis of transient vibration response in topological optimization problems. Firstly, the finite element calculation process of the transient vibration response based on the Newmark method is given. On this basis, the sensitivity formulae of the vibration response objective function to the element pseudo-density are derived using the finite difference method (FDM), the direct differential method (DDM), and the adjoint variable method (AVM). Numerical examples show that AVM has the same calculation accuracy as the DDM, while the precision of the FDM is affected by the perturbation step length. The calculation time of AVM is only about 0.5% of that of FDM. The conclusions of this study can provide a reference for topology optimization.

Precast concrete spreader is the core equipment of precast component production line. The spreader prevents the phenomenon of layering and segregation of concrete materials by continuous mixing. When mixing blades mix concrete materials, the force they are subjected to is very complicated. Taking a common worm distributor as an example, the mechanical model is established, the load condition of the blade is analyzed, the blade is transformed into a cantilever beam model, the grid is divided by Ansys software, and the fixed constraints and force conditions are applied. The results show that the equivalent stress of the blade is much less than its yield strength, and the maximum deformation displacement is also less than the allowable deflection. The strength of the concrete material can be improved by changing the shape of the blade and the Angle of arrangement.

The bolt connection of high-voltage circuit breakers is easy to loosening and failure due to long-term exposure to severe vibration and impact during the opening and closing operation of the circuit breaker. In this paper, the loosening mechanism of bolt connections in high-voltage circuit breakers under axial vibration loads is studied, and verified through finite element simulation and experimental verification. The research results indicate that axial vibration load will reduce bolt clamping force, and make low-grade bolts and lubricated surfaces more prone to loosening. It is obvious that the research conclusions can provide theoretical and engineering guidance for preventing loosening of circuit breaker bolts.

Hand amputation is a highly debilitating event that has severe physical and psychological impacts on an individual's life. While efforts have been made to restore lost functionality through dexterous myoelectric prosthetic hands, achieving natural and robust control for daily use remains challenging. This paper presents a novel biomimetic robotic hand design that aims to provide an affordable, high-precision, and highly applicable solution to better assist those with hand disabilities in everyday living. The proposed design is based on a dual-linkage structure, where each finger is driven by two servomotors to mimic the natural motion of the human hand. The design is based on a double linkage structure, each finger is driven by two servo motors, and supports flexible resistors to detect muscle movements. It adopts a Raspberry Pi control system with a built-in TGAM brainwave monitoring module, which can finely control the movement of the manipulator through brainwaves. The robot has more than ten common gestures built-in, including grasping, stretching, turning, etc. It is made of 3D printing and flexible silicone, with an ergonomic shape. It is powered by a lithium battery and supports USB 3.0 charging. The design realizes accurate motion control and real-time assisted grip adjustment through stress analysis, deep learning and other technologies. The linkage structure improves the control precision, the brain wave control enhances the human-machine interaction, and the FPV real-time video transmission technology and TensorFlow deep learning framework realize the intelligent grip adjustment to meet the daily life needs of the disabled.

To perform monitoring tasks while being comfortable to wear, flexible resistive pressure sensors need to be ultra-thin to avoid sensory irritation from the fit of the device. However, thinning high-performance deformation-affected pressure sensors leads to a decrease in sensitivity due to finite deformation, whereas sensors based on carrier concentration changes are accompanied by low sensitivity due to finite lattice distortion. A ZnO film pressure sensor based on the variation of carrier concentration was prepared by thermal decomposition of zinc acetate, which has a low sensitivity of 0.0296 kPa^-1 due to the limited variation of the distance between the clusters of ZnO molecules. The introduction of ultra-thin ZnO/pedot-pss heterojunctions adds almost negligible thickness to the ZnO film, increasing the sensitivity of the device to 0.1552 kPa^-1. The results show that an appropriate reverse bias voltage to increase the height of the depletion region barrier in the initial state of the device can enhance the sensitivity. However, a higher reverse bias voltage destroys the very thin depletion region barrier formed by van der Waals forces, leading to a decrease in device sensitivity. This work introduces the variation of depletion region barriers with pressure into flexible pressure sensors, providing a new idea for the preparation of ultrathin high-performance flexible resistive pressure sensors.

Using molecular dynamics simulations, we investigated the uniaxial tensile properties of silver nanoplates at 300 K, simulating the effects of constant strain rate and various crack sizes on their tensile behavior. The study found that the interaction between shear stress and dislocations is the primary cause of fracture in silver nanoplates, particularly due to shear stress concentration at the crack tips, which directly affects the movement and arrangement of dislocations. Additionally, smaller crack sizes result in lower yield shear stress, indicating that cracks have a relatively minor impact on the overall strength and toughness of the material. As crack length increases, the crack tips become more pronounced, and new dislocation lines form earlier.

This study employs four machine learning methods, encompassing linear, nonlinear, and integrated models, to forecast the 28-day compressive strength of concrete. The input variables consist of seven concrete constituents: cement, water, fly ash, mineral powder, coarse aggregate, fine aggregate, and water reducer. A dataset comprising 3752 experimental observations on concrete strength is utilized for training and validating the predictive models. By assessing four performance metrics, it is determined that the nonlinear model generally outperforms the linear model, with the integrated learning random forest model exhibiting the highest efficacy. The Dung beetle optimizer is applied to enhance the random forest model, resulting in the development of a robust machine learning prediction model capable of providing more precise estimations of the 28-day compressive strength of concrete.

In this paper, the RV-20E reducer was first modeled in 3D using SolidWorks. Then, modal analysis of the entire RV-20E reducer was conducted using ANSYS software. Subsequently, the meshing frequencies and rotational frequencies of the involute gears, cycloidal wheels, and pin gears were calculated. By comparing the modal simulation results with the formula calculation results, it was demonstrated that the RV reducer does not produce resonance under normal operating conditions. This research holds significant reference value for the structural design of RV reducers.

The dynamic characteristics of the tank directly affect the vibration response and its noise radiation of the transformer. In order to avoid resonance in the frequency band of vibration source, it is necessary to accurately simulate the dynamic characteristics of the tank. In this paper, the structural mode and acoustic-structure coupling mode of the tank are simulated by finite element method, and the influence of insulating oil on the dynamic characteristics of the tank is analyzed. Meanwhile, the natural frequencies and the mode shapes of the tank are tested. The results show that the insulating oil can make the dynamic characteristics of the tank change significantly, and the coupling mode simulation is consistent with the test, which verifies the effectiveness of the acoustic- structure coupling method for the analysis of dynamic characteristics of the transformer tank.

The dynamic and static characteristics of mechanical systems are closely related to the interface contact state. The accurate measurement of interface contact state has become a key scientific problem in the design and control of dynamic and static characteristics of mechanical systems. Ultrasonic detection technology can realize the measurement of contact state, and the accurate measurement of reflection coefficient is the key of this technology. Therefore, this paper carries out theoretical research on the ultrasonic measurement technology of multi-point contact state of ultrasonic lateral waves, studies the influence law of ultrasonic reflection and refraction effect at the interface on the critical lateral waves, builds a multi-point reflection coefficient analysis model, and obtains the true reflection coefficient and measurement error of each measuring point.The theoretical research will provide theoretical support for the accurate measurement of the interface contact state, and has important significance for the reliable design, stiffness optimization and vibration suppression of equipment in aviation, aerospace, Marine and manufacturing fields.

Ultrasonic measurement provides an effective and accurate method for the performance evaluation of mechanical devices, but the edge blurring effect generated in the inspection process will lead to measurement errors and reduce the reliability. In this study, the edge blurring effect is studied, and a matching pursuit model is proposed and established, through which the interference signal is successfully predicted and separated, thus effectively suppressing the influence of the blurred signal on the detection results. Based on COMSOL Multiphysics, a two-dimensional finite element model is established to simulate the reflected signals of ultrasonic waves at the ideal contact interface between structural steel and aluminum. The matching accuracy of the MP algorithm is verified, and the characteristics of the ultrasonic echo signals are also characterized by an atomic function model to predict the reflection coefficients. The experimental results demonstrate that the proposed method reduces the maximum error of the reflection coefficient by nearly 200%, providing an effective approach to suppress edge blurring in the field of ultrasonic inspection. This is of great significance for the evaluation of product quality.

In the field of industrial measurement, structured light technique, as a non-contact, efficient, and high-precision active measurement method, has been widely applied in industrial inspection. Turbine blades are critical components of aero engines, and their surface shape directly affect the performance and lifespan of the equipment. Therefore, accurately measuring their surfaces is of significant research importance. This paper aims to construct a binocular structured light measurement system to meet the high-precision and high-efficiency detection requirements of turbine blades. This study adopts a 12-step phase-shifting and complementary Gray code technique and utilizes binocular reconstruction techniques to obtain three-dimensional point cloud data of the blade surface. Experimental results demonstrate that this measurement system can quickly acquire high-resolution three-dimensional surface data of turbine blades. Compared with traditional contact measurement methods, it has advantages such as non-contact operation, rapidity, and high precision. The accuracy and reliability of this method are verified through measurements on standard spheres and comparisons with theoretical models of the blades. This research provides an efficient and reliable solution for surface detection of turbine blades in the industrial domain, which is of great significance for improving the manufacturing quality and operational performance of turbine equipment.

Utilizing simulation software, this study models the variation in the electric field within the composite insulator crossarm when condensation occurs on its inner surface and examines the effects of moisture intrusion on the internal insulation characteristics of the composite insulator crossarm. The simulation results indicate that droplets on the inner surface of the composite crossarm can cause distortions in the internal electric field, making it more prone to partial discharge phenomena, and may even lead to surface flashover when the droplets are densely packed. In the case of moisture intrusion into the cavity, the condensation alters the insulating state of the inner surface of the composite crossarm, thereby affecting the characteristic quantities of internal flashover voltage and leakage current.

Due to the inconvenient use of sensors in structural health monitoring, vision-based, non-contact vibration measurement methods have been rapidly developed. However, most vision-based methods necessitate the installation of targets. Additionally, manually designed filters typically apply to a single scenario, exhibiting poor adaptability to diverse working conditions. This paper focuses on vision-based structural vibration measurement and introduces a novel learning-based method that combines motion magnification and edge detection technologies to address the issue of poor detection accuracy caused by small vibration amplitudes in full-field photographs. Vibration signals are extracted by detecting pixel changes at the edges of the structure. Furthermore, we use a learning-based motion magnification technique for structural modal identification. Experimental results from vibration detection tests on wind turbine towers demonstrate the effectiveness of our method. The system’s frequency detection error is less than 1.5% compared to accelerometers.

In this paper, the vibration characteristics of the plate structure are analyzed. Then, according to the vibration characteristics, a surface-attached local resonance element coupled with its natural frequency is designed. The vibration damping performance is studied by finite element simulation. The results show that the natural frequency of the local resonant element can be effectively designed by adjusting the material and structure parameters. The natural frequency can be increased by increasing the modulus of the elastic material and the natural frequency can be reduced by increasing the radius of the mass block. The resonance unit attached to the plate structure can play a significant damping effect, the average vibration acceleration level of 10~500Hz is reduced by about 9dB, compared with the uniform rubber plate, with a smaller additional weight to achieve better damping effect, and has a good application prospect in the low-frequency vibration damping application.

In this paper, the explosion impact resistance of bolt-connected structures is explored, and ALE explosion simulation algorithm is used to simulate and analyze bolt-connected platforms under explosion environment, and the accuracy of the finite element model is verified by comparison with the platform explosion test. Different modeling methods were used to explore the influence of different bolt models on the simulation results. It was found that the solid bolt model had the best effect and the error was the smallest, 1.5%, compared with the experiment. The other parameters of the bolt were kept unchanged, and only the bolt strength grade was changed. The influence of different bolt strength levels on the simulation results was explored. It was found that the maximum displacement of the target plate continued to decrease with the increasing of bolt strength level, and the anti-knock performance continued to improve. The effects of different bolt models and bolt strength grades on the explosion impact resistance of bolt-connected structures are summarized and analyzed, and some theoretical basis and reference are provided for bolt-connected body design of protected vehicles.

This paper investigates the feasibility of improving the surface hardness, wear resistance, fatigue strength, and corrosion resistance of 25Cr2MoV steel through gas nitriding. The experiment tested various nitriding potentials (3, 1, 0.5, 0.2) at 520°C for 5 hours on quenched and tempered 25Cr2MoV steel. The microstructure, phase composition, brittleness, and wear performance of the nitrided layer were systematically analyzed using microstructure observation, XRD analysis, Vickers hardness testing, and wear tests. Results show that as nitriding potential decreases, the thickness of the compound layer significantly reduces, while the depth of the nitrided layer remains unchanged. At lower nitriding potentials (K_N=0.2, 0.5), the γ′ single-phase compound layer on the surface exhibits higher plasticity and wear resistance. Conversely, higher nitriding potentials (K_N=1, 3) increase the ε phase content, leading to greater surface brittleness and reduced wear resistance. This study demonstrates that optimizing gas nitriding process parameters can significantly enhance the overall performance of 25Cr2MoV steel, offering an effective surface strengthening method for practical engineering applications.

Wire-arc additive manufacturing (WAAM) process has advantages such as high deposition efficiency, large-scale parts, and low production costs. However, the TA15 titanium alloy fabricated by WAAM still exhibits issues including coarse grain, low strength and hardness, as well as poor corrosion resistance. This study introduces activating fluxes of CaF₂ into the WAAM process. The results show that CaF₂ additions refines the plate-like α phase and inhibits the transition of β to α phase. The improved microstructure increases the tensile strength by 8.36%, the hardness by 14.2%. Moreover, the corrosion potential and current increase (or decrease) from -0.395V, 6.384×10^-6A/cm³ to -0.294V, 2.499×10^-6 A/cm². Therefore, this study provides a potential approach for improving the microstructural properties of WAAM-prepared titanium alloy (TA15).

Due to the presence of front and rear conveyor drive motors and other equipment at the end of the fully mechanized mining face, the space is cramped. The commonly used anti-four-bar transition support system provides even support for the front and rear columns, but its structural limitations result in weaker support performance compared to the standard four-bar support system. To maintain a consistent center distance for the conveyor, the base must be slightly retracted, which leads to a reduction in support strength. Therefore, the strength and stability of the support system require validation. The mechanical properties of the anti-four-bar transition support system for caving coal were analyzed using the software ANSYS Workbench. Under the condition where the top beam is subjected to an eccentric load and the base is subjected to a torque load, the overall stress and displacement changes of the support system were not significant. However, analyzing only the entire support system can lead to unreasonable local design. By analyzing the individual components, it was determined that the top beam experiences the maximum stress of 185.29 MPa, which requires the enhancement of material strength; the diagonal beam has a maximum stress of 69.18 MPa and a maximum displacement of 0.49034 mm, which necessitates increasing the thickness of the reinforcing plates; and the base has a maximum displacement of 0.46135 mm, which requires an increase in the transition fillet radius. Modal analysis was conducted on the top beam and base, and it was found that their natural frequencies are all greater than 50 Hz, preventing mechanical resonance with other equipment. By analyzing the regular patterns of mine pressure, it was observed that the working face pressure tends to be higher in the middle and lower at both ends, with the initial peak pressure reaching 37.8 MPa and periodic pressures ranging between 30 to 37.5 MPa. The research findings provide reference data for subsequent support system studies.

To study the influence law of parameters such as print layer thickness, print speed, placement angle, and fill angle on the tensile properties of specimens in the process of fused deposition 3D printing of ABS specimens, a 4-factor, 3-level orthogonal experiment was used, and through the range analysis deviation and analysis of variance of the test results, the magnitude of the influence of the four factors on the tensile properties of ABS specimens was obtained in the following order: placement angle, fill angle, print speed, and print layer thickness. The level of influence of the placement angle was significant, and the optimum tensile properties of ABS specimens were determined within the range of orthogonal tests to be obtained at a print layer thickness of 0.3 mm, a print speed of 55 mm/s, a placement angle of 45°, and a fill angle of 90°. The results of this study are of great significance for the in-depth analysis of the relationship between the placement angle and the tensile properties of the specimens and provide a certain theoretical basis for the optimization of the 3D printing parameters of the actual ABS specimens.

Controllable Pitch Propeller (CPP) is a specialized propulsion device for ships, where the oil pipe is the core power component. Once the support bar welding joint attached to its surface breaks, it can lead to serious safety hazards. In the paper, finite element method was used to simulate the welding process of the outer oil pipe and the blade-shaped support bar, and the reliability of the model was validated through experiments. Based on this model, three different welding structures - segmented interval welding, concentrated segmented welding, and full welding - as well as different support bar materials were studied. The results show that the maximum residual stress generated by segmented interval welding was approximately 5.7% lower than that of concentrated segmented welding, with little difference between concentrated segmented welding and full welding. The maximum residual stress generated by welding outer oil pipes with Q355B material support bars was approximately 6.53% lower than that of QAL9-4, which provides a reference for pipe welding.

The icing hazard of outdoor equipment seriously threatens stable operation of power grid. The slippery surface has the possibility of application in the fields of antifouling, anticorrosion and anti-icing due to its water droplet sliding performance. In this study, the slippery surface was prepared on the surface of 7075-T651 aluminum alloy by anodic oxidation method, and the static and dynamic anti-icing properties of aluminum alloy slippery surface were studied. The results show that the ice adhesive strength of the prepared slippery surface is as low as 6 kPa. The icing time of the slippery surface is 5700 s, and the complete frosting time is 3000 s. The slippery surface exhibits excellent dynamic anti-icing performance, and its icing weight is 61 g. This study provides useful information for the application of aluminum alloy slippery surface in the field of anti-icing.

Space membrane structures are distinguished by their low surface density, reduced rigidity, and lightweight nature. Yet, they face numerous dynamic challenges in orbital functioning, highlighting the prominent vibration issue in these membrane antenna designs. This study conducts a numerical simulation of thin-film antenna architecture using Abaqus to examine how film thickness, prestress, and various elements influence the structure's dynamic behavior. Findings indicate that film thickness primarily influences the mass matrix, while prestress impacts the stiffness matrix. Improving the matrices for mass and stiffness reduces the displacement of the mid-point, leading to a more consistent and efficient dynamic reaction of the structure in handling vibrations. The research in this paper provides an important reference for vibration control and performance optimization of thin-film antenna structures.

With the significant increase in the application of composite materials in engineering, it has become an important topic in the engineering field to study the impact behavior and damage mechanism of these materials under different impact conditions. This paper reviews the commonly used high and low-speed impact test methods for composite structures in recent years. It briefly introduces the design principles, advantages, disadvantages, and applicable scope of each method. Finally, it summarizes the discussed high and low-speed impact test methods for composite structures and provides some suggestions for future development, aiming to offer useful references for the advancement of impact test methods for composite structures.

According to the demand of the cigarette market, the group's technical center has developed and produced a new product, which has a cigarette specification of 8.6mm x 84mm and is packaged in a hard box. Based on the equipment configuration of our factory, it has been decided to use the GDX2 packaging machine with a production diameter of 7.8 cigarettes to achieve packaging of 8.6 cigarettes, with an increase in the length of single inner lining paper. Through theoretical analysis and calculation of the paper feeding capacity of the inner lining paper acceleration device, it was found that the acceleration device on the original equipment cannot meet the inner lining paper conveying requirements of the new specification cigarette packaging. After the transformation of the transmission system of the inner lining paper acceleration device, the gear transmission ratio of the acceleration roller was changed to ultimately improve the rotation speed of the acceleration roller. At the same time, in order to increase the stability of the inner lining paper transportation, the negative pressure suction belt and acceleration wheel of the inner lining paper were modified to ensure stable transportation of the inner lining paper when producing the diameter 8.6 cigarette specification on the GDX2 packaging equipment. After the transformation, the production of cigarette products with a diameter of 7.8 was achieved on the GDX2 packaging machine with a diameter of 8.6. The production speed of the original equipment was increased to 300 packs/minute, and the equipment efficiency reached 92.4%; The quality defect rate of the inner lining paper has been reduced by 2.72 ‰, and the transformation has achieved the expected effect.

During the process of oil drilling and extraction, the drill-column often fails under compound load conditions, and most of the studies on oil pipe threaded joints focus on the drill pipe threaded joints, but there are few studies on the coring tool threaded joints. Based on this, a study was conducted on φ121 coring tool threaded joints, revealing different mechanical characteristics of normal and specialized threaded joints which are subjected to combined axial and torsional loads. Results showed that: under the upper buckling torque, stress concentration of the normal threaded joints appears close to the shoulder area, whereas the stress distribution is more regular and dispersed for the specialized threaded joints, focusing around the primary two shoulders. The contact pressure at the shoulder of specialized threaded joint behaves lower than that of the normal threaded joint, indicating the primary two shoulders of specialized threaded joint can reduce the axial pressure caused by upper buckling torque. Furthermore, within the range of 0 to 100 kN axial pressure, the extreme operation torque of specialized threaded joints is significantly higher than that of normal threaded joint, demonstrating superior load-bearing performance.

The novel 0.6 wt% 3,4-dimethoxy-styrene-3-methylbenzothiazole p-toluene sulfonate (DOBT)−polyvinyl alcohol (PVA) binary composite film based flexible sensor is fabricated in this work, and its piezoelectric and third-order nonlinear optical absorption properties are investigated through using linear motor and femtosecond open-operture Z-scan technique, respectively. Piezoelectric measurements indicate that this sensor exhibits desirable piezoelectric properties with an open-circuit voltage of 1.75 V and a short-circuit current of 57.10 nA under an external compressive force of 10 N at 1 Hz. Z-scan traces reveal when irradiated by a 520 nm laser beam, this sensor with a linear transmittance of 94.0% can exhibit remarkable optical limiting performances. In particular, both the piezoelectric and third-order nonlinear optical limiting responses that observed from this sensor originate from the ionic organic molecule DOBT alone, suggesting a promising application prospect of new DOBT in the fields of piezoelectricity and nonlinear optics. These results together establish an experimental foundation for applications of 0.6 wt% DOBT−PVA binary composite film based flexible sensor in sustainable self-powered and high-energy laser protection systems in the future.

The ultimate load bearing performance of high strength bolt connection structure is analysed, the current mainstream connection method is welding, and high strength steel in the process of high temperature welding will appear heat-affected zone, resulting in the reduction of life, this paper proposes to use high strength bolt connection structure instead of welded connection, through the establishment of the bolt connector finite element model to achieve the high strength bolts shear load bearing analysis of the working condition, to analyse the change of ultimate load bearing capacity under the influence of different The change of ultimate bearing capacity under the influence of different bolt apertures and bolt diameters is analysed. It is found that the appropriate increase of bolt aperture diameter is conducive to the transfer of bolt load, avoiding the bolt pull-off failure caused by stress concentration, thus improving the overall load bearing performance of the connection; while the increase of bolt diameter, the failure form of the bolt connection structure will be from the shear failure to the plate aperture wall crushing failure, the edge of the necking deformation, so it is necessary to avoid the selection of too large a bolt diameter.

Based on the characteristics of graphite electrode materials, diamond coated cutting tools were used to replace conventional Carbide(WC) milling cutters for high-speed milling of graphite. The tool life curve of diamond coated cutting tools for high-speed milling of graphite electrode materials was mainly studied, and compared with TiAlN coated cutting tools and Carbide(WC) cutting tools; Studied the effects of cutting speed, feed rate per tooth, radial cutting depth, axial cutting depth, forward and backward milling methods, and different material tool factors on cutting force, as well as compared with TiAlN coated tools and Carbide(WC) tools; Optimizing process parameters based on orthogonal cutting force experiments; At the end of the paper, a study was conducted on the surface quality of diamond coated tools and TiAlN coated tools for high-speed milling of graphite electrode materials.

65Mn steel is an alloy steel commonly used for manufacturing circular saw blades. In this study, CO2 continuous laser transformation hardening (LTH) was performed on 65Mn steel to investigate the effects of different laser powers on the microstructure and mechanical properties of the steel. The mechanical properties of the samples were evaluated using a tensile testing machine. The hardness and surface residual stress were measured with a Vickers hardness tester and an X-ray residual stress measuring instrument, respectively. The microstructure and fracture morphology of the samples were examined using scanning electron microscopy, and the fracture mechanism was explored. The experimental results revealed that the microstructure of the laser transformation hardened (LTHed) samples consisted of needle-like martensite, retained austenite, and carbides. The highest hardness of the LTHed samples was found to be 2.75 times greater than that of the untreated matrix. Additionally, residual compressive stress was generated on the surface of the LTHed samples. LTH significantly improved the yield strength, tensile strength, and elongation of 65Mn steel. The fracture toughness of the LTHed samples showed a decrease in porosity and exhibited a quasi-cleavage fracture morphology.

Replacing traditional steel-cored aluminum stranded conductors with heat-resistant conductors is a key method for upgrading and increasing the capacity of old transmission lines, but heat-resistant conductors generally have lower electrical conductivity. To solve this problem, this paper develops a high-conductivity, high-strength heat-resistant aluminum alloy material using an Al-Zr alloy base with the addition of metallic elements. A rolling process experiment was carried out to investigate the key process parameters at various rolling stages, achieving a match between material formulation and process. The result is a high-conductivity, high-strength heat-resistant conductor. The single-wire aluminum alloy achieved a tensile strength of 136 MPa and electrical conductivity of 61.64% IACS, with the stranded conductor maintaining 94% of its residual strength.

Hydrogen peroxide (H₂O₂) is an important component of reactive oxygen radicals (ROS), and excessive hydrogen peroxide triggers oxidative stress, leading to apoptosis and tissue damage; therefore, it is important to achieve efficient detection of H₂O₂. Near-infrared II region fluorescent probes have the advantages of deeper tissue penetration and higher resolution, which are important in the field of bioimaging. In this project, an indole-based near-infrared region II fluorescent probe that specifically recognizes hydrogen peroxide was designed and synthesized based on the Cy7 phlorocyanine dye by sequentially linking 2-methylbenzo[c,d]indole, (E)-2-chloro-3-cyclohexene-1-carboxaldehyde, and 3,6,9-trioxa-1-aminodecane with trimethyl borate as the recognition group. The structure of the probe was characterized by nuclear magnetic resonance (NMR), and the imaging effect and tissue penetration ability of the probe were tested. It was found that the fluorescent probe had high imaging resolution and deep tissue penetration at the NIR-II wavelength, and exhibited high responsiveness and selectivity for hydrogen peroxide.

UV-curing 3D printing technology has been widely used in fields like metamaterials, mechanics, soft robotics, and sensors. However, it struggles with fabricating structures with uniform mechanical properties. This research introduces grayscale digital processing in UV-curing 3D printing to create functionally graded or composite structures with varied performance. We developed a novel method to experimentally verify how grayscale values impact the mechanical properties of 3D-printed structures. By applying different grayscale values to specific regions, we achieved varied mechanical properties within a single structure. Our experiments showed precise control over elongation at break, fracture force, and fracture toughness. The results demonstrate that grayscale digital processing can significantly enhance the versatility of 3D-printed structures. This approach is promising for advanced engineering applications requiring complex and multifunctional materials, highlighting its potential to advance UV-curing 3D printing technology.

Humans tend to perceive the properties of an object by the way they interact with the objects around them, for example, by simply shaking a container to determine the viscosity of the liquid inside it. Nowadays, as robots are widely deployed in life, we want to give them the same perception capabilities to make subsequent correct motion decisions based on the perception results. Existing studies on liquid viscosity perception are mainly based on visual sensors, but visual perception is hindered when the liquid is obscured by an opaque or closed container. To make up for the shortage of visual perception, we innovatively propose a six-axis force/torque sensors perception method based on the end of the robot arm. By collecting the oscillation information of the liquid in the container after shaking, using the CATCH22 time series analysis package to extract important features from the time series data, and combining with Neighborhood Component Feature (NCA) technology for model optimization, we tested the classification effect of the model on seven liquids in the viscosity range of 1-1000cst and common liquids in daily life respectively. The experimental results show that our method achieves 99.6% accuracy in classifying water, milk, yogurt, and detergent, which are common liquids in life, and 93.3% accuracy on seven liquids with similar viscosity, proving the feasibility of the force-information-based approach to perceiving liquid viscosity.

Soil abrasion on plows, shovels, and other cultivation tools causes a lot of material consumption, especially in the sandy soil environment of southern Xinjiang. Therefore, in the design of agricultural machinery products in southern Xinjiang, it is necessary to consider the friction and wear of materials that touch the soil components. In order to effectively evaluate the wear and tear of high-speed plow contact soil components in the cultivated land environment of southern Xinjiang, the research was conducted using the core material of 65 Mn steel friction pairs between southern Xinjiang sand and contact soil components. By carrying out friction and wear tests at different time stages and observing the morphology and size of wear surfaces at different time durations, a gray GM (1, 1) model was used to establish a wear prediction model based on the working hours. The results show that using the grey theory to predict the wear amount of friction pairs between sand and 65 Mn steel in southern Xinjiang has a good effect. The maximum error between the predicted and experimental values is 5.4%, and the average relative error is 1.97%. The adoption of this prediction model avoids the need to carry out a large number of wear tests and solves the problem of designing the wear life of the core parts of the touchdown of agricultural machinery, thus providing a theoretical index reference for the amount of wear for product optimization.

This study investigates water and transformer oil permeability in gravel layers with varied particle proportions. The specified experimental platform was established. 50-80 mm gravel samples and 1-10 mm particles were tested. The results indicate that for a 50-80 mm gravel layer, the permeability coefficient remains relatively unchanged when the mass fraction of fine particles does not exceed 12.7%. Once the mass fraction of fine particles exceeds 12.7%, the permeability coefficients for water and oil decrease according to a power function, with a more pronounced decrease in oil permeability. Combining ACE regression and experimental results, empirical formulas describing the permeability coefficients of water and oil in the gravel layer concerning the mass fractions of 5-15 mm and 1-5 mm particle sizes were derived as well. This research provides practical insights for optimizing gravel layer permeability in facility design and maintenance.

Tremendous efforts have been made towards addressing the Li-dendrite issue for enhancing the practical applicability of Li metal batteries. However, challenges remain in exploring simple and efficient surface engineering for achieving uniform Li plating/stripping. Herein we report a one-step chemical substitution method (3Li + ZnCl₂ = LiZn + 2LiCl) that simultaneously constructs a LiZn/LiCl surface layer ontometal Li. The obtained Li- LiZn/LiCl anode exhibits a corallinelike cross-linked surface structure, in which the LiZn alloy component is beneficial for uniform Li-ion deposition, while the LiCl component can prevent the electron transfer from inside Li to the surface layer, so that Li plating occurs between bulk Li and LiZn/LiCl layer, inhibiting the Li-dendrite formation. As a result, this anode enables promising electrochemical performance, and a representative LiNi_0.8Co_0.1Mn_0.1O₂//Li-LiZn/LiCl cell maintains 77% capacity retention (~ 185 mAh g^-1) after 300 cycles at 1.0 C rate. This studyprovides a straightforward and effective surface engineering for improving the anode of Li metal batteries.

Zn-Sn-P nanoparticle materials were synthesized by a simple and green low-temperature phosphating method, and sodium-ion batteries were assembled with Zn-Sn-P materials as the anode, as well as the performance of the sodium-ion batteries were investigated. The outcomes showed that the sodium-ion battery with Zn-Sn-P material serving as the anode demonstrated a 99% Coulombic efficiency (C.E.) and a high specific capacity of 652.4 mAh g^-1 after 700 charge-discharge cycles. The results showed that the nanoparticle morphology of the material effectively alleviated the volume change throughout the process of charge/discharge, which was conducive to the improvement of the interfacial stability of the material. Meanwhile, the phosphide process also offers more active websites for Na⁺ embedding and synergistically enhances the storage of Na⁺, which improves electrochemical performance.

In-situ preparation of ultrafine silicon carbide (SiC) powders had been successfully achieved in the Potassium Chloride (KCl) and Sodium Chloride (NaCl) molten salt system. The results showed that the optimized preparation conditions for SiC in the air were: a reaction temperature of 1400℃, a carbon-silicon ratio of 1:7, and a molten salt ratio of 1:4. The optimal temperature for synthesizing SiC in a vacuum was 1300℃. Notably, SiC synthesized at 1300℃ in a vacuum had a smaller particle size and a more uniform distribution compared to SiC prepared in air. This study successfully prepared ultrafine SiC powders using the molten salt method and underscored the significance of vacuum conditions in optimizing SiC performance and particle size distribution.

The thickness of a metamaterial reflects its ability to regulate sound waves and vibrations. The study proposes an ultrathin underwater acoustic absorbing metamaterial using a topology optimization method for reverse design. The optimized metamaterial obtains the capability of extraordinary acoustic absorption in the low-frequency case, achieving an absorption coefficient of 70% for the waves with a wavelength of 100 times thickness. With the combined effect of cavity resonance and wave mode transformation, the metamaterial achieves an average absorption coefficient of more than 90% for the acoustic wave with wavelength 7.5 to 100 times thickness. The research significantly advances the practical application of underwater acoustic metamaterials.

The processing effect of 45 steel laser quenching is affected by a variety of process parameters. In this paper, a simulation and experimental synergistic analysis method for laser quenching temperature field is proposed to accurately predict the laser quenching temperature field distribution and analyse the influence of different factors on the quenching effect. A solid heat transfer simulation model for the laser quenching process of 45 steel was established using COMSOL software. The laser quenching test bench was built and the 45 steel laser quenching test was carried out. The solid heat transfer simulation model was optimized through the synergistic analysis method. The average relative error between the peak temperature at the characteristic point and the test data is 3.82%, which is 41.19% lower than that before optimization.

If car interior parts come into contact with drivers and passengers for a long time and contain harmful elements such as lead, cadmium, antimony, arsenic, etc., under the erosion of human sweat, some harmful elements will dissolve, causing sensitization or other hazards. This type of research and reporting is common in the textile and clothing industry. Due to the diverse types of automotive interior materials, complex manufacturing processes, and the use and introduction of harmful elements in the production process, it is of great significance to carry out limit requirements and comprehensive testing of soluble elements in automotive interior parts, especially for the health attributes of sensitive infants and young children, for the health of automotive products. This article mainly focuses on the Chinese automotive market, selecting 10 different levels and types of automotive interior components as representatives. Based on relevant standards or self built testing methods, 14 migration elements that may exist in automotive interior products and cause harm to drivers and passengers are thoroughly tested. The health status of interior products in the Chinese automotive market is analyzed, and the ways to introduce harmful migration elements are explored, Provide reference for healthy material selection on the production end and green consumption on the consumption end.

In recent years, the aerospace industry has widely embraced carbon fiber reinforced polymer (CFRP) composites due to their exceptional specific strength and stiffness. However, CFRP exhibit inherent deficiencies in electrical conductivity, thermal conductivity, and electromagnetic shielding properties in comparison to traditional metal counterparts, rendering them susceptible to severe damage upon lightning strikes. Enhancing electrical conductivity emerges as the fundamental and most effective measure to mitigate lightning-induced damage in CFRP composites. This review provides a comprehensive review of recent efforts and advancements in lightning strike protection (LSP) achieved through improvements in the electrical conductivity of CFRP composite. Various methodologies have been adopted to enhance the electrical conductivity of CFRP composite, either enhance the overall electrical conductivity of the material or its surface. The review categorizes these materials into two aspects: surface LSP and overall LSP. Some of these strategies have demonstrated excellent lightning strike protection and hold great potential in practical applications. Finally, the article offers insights into the prospective future development of LSP for CFRP composite.

This paper produced tensile specimens of Sn₆₃Pb₃₇ solder and conducted uniaxial tensile tests under different temperature conditions. Through nonlinear fitting of the test parameters, the nine parameters of the Anand constitutive model were obtained, and the Anand constitutive model of the solder was constructed. Abaqus finite element software was used to simulate the creep behavior of BGA solder balls during temperature cycling, and the stress and life of the solder balls were studied. The analysis results show that the peripheral solder balls have greater stress, strain and lower lifespan. The greatest risk of fracture is at the root of the solder ball. Underfill glue can effectively improve the reliability of the solder ball.

Refractory high entropy alloys with outstanding high temperature properties and irradiation tolerance have been proposed as potential structural materials for advanced nuclear systems. However, the stability and mechanical properties of the alloys will be significantly reduced by the interstitial impurities such as C, N and O, through the component segregation and precipitate formation. To understand this process, the formation and segregation energy of interstitials in TiVTaNb RHEA are studied by using first-principles calculations. We found that interstitial impurities prefer to segregate around Ti atoms, and C/N atoms tend to co-segregate with O atoms. Moreover, the precipitates with higher O content are more stable than the others. These results will be helpful to unveil the mechanism of the precipitate formation in RHEAs.

Conventional design strategies for acoustic metamaterials necessitate extensive expertise and specialized acumen on the part of designers, entailing significant computational expenditures in the design process. The merits of deep learning methodologies, leveraging a data-centric paradigm without dependence on empirical designs, have attracted escalating attention in the contemporary academic discourse. Consequently, this investigation delves into its application for the design of acoustic metamaterials. We employed a Convolutional Neural Network (CNN) to address the forward prediction challenge, attaining an impressive prediction accuracy of up to 98%. Building upon these results, we formulated a conditional Deep Convolutional Generative Adversarial Network (c-DCGAN) to confront the inverse design conundrum. The network is capable of swiftly generating topological structures that align with predetermined absorption curves, thereby demonstrating robust generalization prowess in inverse design scenarios. It is proficient in executing inverse design tasks accurately for a diverse array of previously unseen types of feature curves.

Insulation pull rod is an important component of SF₆ combined electrical equipment, which mainly plays the role of transmitting the mechanical load and insulation when the switch acts. To illustrate its failure mechanism, this paper considers the stability issue of cylindrical shells composed of anisotropic materials and employs finite element analysis (FEA) to model composite material tubes using a curved coordinate system. A model of aramid composite tube-type insulation pull rod was established to ensure its structural compliance with ultra-high voltage standards. Mechanical property simulations were conducted on the pull rod, Subsequently, the buckling characteristics of the pull rod under different end conditions were analysed. Finally, the multi-layer composite material tube was adopted to analyse the effect of the laying angle deviation of layers on buckling. The results show that the method using the curved coordinate system can effectively model and analyse anisotropic cylindrical tube materials. Under static load, the stress distribution on the rod is not uniform, with significant stress concentration at the junction of rod and metal joint. Different end connection condition has a great impact on the critical load for buckling instability. When both ends are fixed, the critical load is eleven times that of one end being fixed. The deviation of the primary material direction of the cladding from the axial direction in the rod results in a decrease in the critical load of buckling. When the laying angle deviation exceeds 3°, each additional degree of deviation decreases the critical buckling load by approximately 1.6%. This paper provides references for the stress characteristics and causes of damage in ultra-high voltage insulation pull rod.

High purity copper is widely used because of its excellent properties, but the method of preparing high purity copper needs to be solved urgently. In this paper, the electrolyte flow characteristics between the anode and cathode, as well as the effect of wrapping filter cloth on the purity improvement of cathode copper were studied through simulation and copper electrolytic refining experiments, respectively. The results showed that the electrolyte between the cathode and anode plates presented the flow state of "circulating vortex"; the method of covering the filter cloth on the cathode plate could significantly improve the purity of copper cathode, and the smaller aperture of the filter cloth, the lower the content of impurity elements in the copper cathode; by wrapping the filter cloth on the cathode plate in the process of copper electrolytic refining, the high purity copper (5N) could be obtained.

Bipolar plates account for most of the weight and cost in PEMFC, and also play a crucial role in it, with carbon/polymer composites owning great prospects. Combination of raw materials largely determines the properties and performance of BPs. This paper focuses on both the conductivity and mechanical performance of CBPs, and reviews the properties of the BPs prepared by different combinations of raw materials from the perspectives of a variety of carbon fillers and polymer materials, respectively. Finally, the paper summarizes the changes in the properties of CBP brought about by the use of different raw materials and gives an outlook on future research directions.

The design allowable of materials is an important index of the mechanical properties of civil aircraft materials, and relative computation bases on the distribution assumption and the corresponding distribution. According to the computation, the results of the same sample with different distribution math-models are obviously different, so it is necessary to determine the distribution by fitting the distribution of samples in order to calculate the allowable value. This paper discusses the method of determining the fitting result by introducing P-P plot and R-square when the material property data sample passes the Anderson darling fitting test for two or more distributions under corresponding confidence level. The results show that when the sample size is low, the P-P plot and the r square can provide reference information to determine the best fitting results, especially when the sample obeys Weibull distribution.

The QAl 9-4 aluminum bronze was treated with plasma electrolytic oxidation in this article, resulting in a comparatively thick oxide film that is about 24μm thick on the surface. The oxide film was mainly composed of α-Al₂O₃, Cu₂O and γ-Al₂O₃. After the experiment, the corrosion resistance improved, the corrosion potential slightly increased, and the electrochemical impedance significantly increased. The TA31 titanium alloy served as the cathode, and QAl 9-4 aluminum bronze with its plasma electrolytic oxidation film layer served as the anode after galvanic coupling of QAl 9-4 alloy with its plasma electrolytic oxidation and TA31 titanium alloy. QAl 9-4 aluminum bronze occurred for plasma electrolytic oxidation，which reduced the corrosion potential and electric corrosion current coupled with the TA31 alloy puppet and the corrosion rate of QAl 9-4 aluminum bronze, while inhibiting the occurrence of electric puppets.

Aluminum fluoride is the main component of fluorophosphate optical glass, and its structure and properties have important effects on the microstructure and chemical stability of optical glass. In this paper, the properties of aluminum fluoride from 3 different manufacturers were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), and the corresponding optical glass was prepared by melting method. The influence of powder morphology on the refractive index and internal defects of fluorophosphate optical glass was studied. The results show that AlF₃ with coarse particle size and porous surface structure can meet the requirements of refractive index and internal defects of fluorophosphates optical glass.

Hydrophobic metal surfaces have broad application prospects in various fields due to their excellent properties like self-cleaning and anti-icing. However, the current methods to construct micro/nanostructures required for good hydrophobicity tend to be high-cost and may involve dangerous chemical reagents, which restrains further applications of these surfaces. In this paper, we propose a green and low-cost boiled water treatment method to fabricate micro/nanostructures on aluminum substrates, and the surfaces show good hydrophobicity after low surface energy modification. The preparation process for the micro/nanostructures is free of any chemical reagent, and the whole process can be completed within 1.5 h. Fabrication mechanism of this method is investigated by observing surface micro/nanostructures using a scanning electron microscope (SEM) and analyzing chemical compositions via an energy-dispersive X-ray spectroscope (EDS). The method may also be applied to construct the micro/nanostructures on other metal materials, and is expected to facilitate large-scale preparation and application of hydrophobic engineering metal surfaces.

The microstructure of AZ61 alloy containing 1.5%Sm were studied. The results showed that the aged AZ61+1.5%Sm alloy consists the α-Mg, Mg₁₇Al₁₂ eutectic phase and high melting point Al2Sm phase. Al2Sm phases can acting as nucleation site of a-Mg matrix and refine the microstructure of AZ61 alloy.

The study aims at providing a method for topology optimization of compliant mechanisms with multiphase anisotropic materials. The element stacking method is adapted to establish multiphase anisotropic materials interpolation model. The mutual strain energy of the mechanism is maximized under the volume constraint. The numerical example demonstrates the availability of the design method. The comparison of the results with single-phase anisotropic materials shows that the mutual strain energy of the compliant mechanism with multiphase anisotropic materials is greater.

Annular metamaterials (AMs) which can suppress radial vibrations have received significant attention. In this paper, a novel AM is designed to suppress radial vibrations. Utilizing a mass-spring model, the radial vibration bandgaps (BGs) of the AM are calculated theoretically. Finite element simulations are conducted to analyze the mechanism behind the formation of these BGs, with results indicating pronounced local resonance characteristics within the BGs range. Further investigation into the vibration transmission characteristics of the AM is conducted using both finite element analysis and experimental methods. Further studies on the vibration transmission characteristics of the AM are performed using finite element analysis and experimental methods. The findings confirm a strong alignment between the theoretically calculated BGs and the observed vibration transmission characteristics, demonstrating the efficacy of the AM in suppressing radial vibrations within the BGs. The AM proposed in this study offers wide engineering applications in annular component, such as vibration reduction in rotating machinery and pipeline.

In the process of fabrication, installation, maintenance, and use, the laminate structures of composite will inevitably experience impact from foreign objects, resulting in delamination damage. In the aerospace vehicle service process, the fatigue damage evolution and failure mechanism become intricate due to the coupling and influence of various impact-induced damage modes under complex fatigue loads. This paper introduces initial impact damage into two typical laminate structures using the drop hammer impact method. Based on A-scan and C-scan technologies, the damage modes were obtained, and compressive buckling fatigue tests were carried out. It was found that after one million cycles, no damage propagation was observed, and there were no significant changes in the stiffness, buckling load, and load-bearing capacity of the specimens. This verifies the design concept of static coverage fatigue and non-propagation of damage under compression loads for skin laminates, providing basis and support for the composite design of aircraft.

In mechanical assembly and engineering, the integrity of fastening systems is crucial for the reliability and durability of structures and machinery. This study investigates the failure mechanisms of stainless steel self-locking bracket nuts and titanium alloy screws, which are critical junction points in various engineering applications. Through comprehensive testing and analysis, focusing on the morphological characteristics of the failed components, the research reveals that pairing stainless steel self-locking bracket nuts with blue anodized titanium alloy screws leads to pronounced galling, known as "bite death." Remarkably, the study finds that using titanium alloy screws lubricated with molybdenum disulfide significantly mitigates this adverse effect. Specific data indicate that untreated screws required torques of 2Nm, 3Nm, and 5Nm for M3, M4, and M5 sizes, respectively, while treated screws only required torques of 0.2Nm, 0.7Nm, and 0.9Nm to pass through the self-locking nuts. This investigation highlights the importance of material compatibility and lubrication in preventing fastener failure, providing essential insights for optimizing screw and nut combinations in engineering designs.

To solve the problem that the material removal rate and surface roughness can not be accurately predicted in electrical discharge machining (EDM), the temperature field, melting and solidification process of silicon single crystal in single pulse EDM are simulated, and the morphology and size of a single erosion crater is obtained. The predicted values for surface roughness (SR) and material removal rate (MRR) of machined silicon single crystal are derived from calculations using a continuous pulse discharge model. Experimental results indicate that the relative error between the predicted and experimental values for the MRR is 5.4%, and the relative error for the surface root mean square roughness is 6.2%, which verifies the accuracy of the model.

Accurately predicting the hygroscopic behavior of composite materials is of great significance for the reliability design and life assessment of composite products. In this paper, a method was proposed for mesoscopic modeling and simulation of the hygroscopic behavior of composites based on fiber arrangement image features. Benefiting from the method the problem was solved that the classical model cannot take into account the influence of fiber arrangement mode on moisture absorption rate. The distribution laws were discussed on moisture absorption rate at different moments and different paths, and the differences were compared between the fiber order-arrangement and disorder-arrangement models. The simulation results showed that the obstruction of water molecule diffusion was more severe in the disorder-arrangement model established from the fiber arrangement images, and the moisture absorption rate of the composite was lower than that of the order-arrangement model. Finally, the accuracy of the disorder-arrangement model was verified by two groups of hygroscopic experiments at temperatures of 40°C and 80°C, respectively. The prediction accuracy of the model for the moisture absorption curve reached more than 0.92.

In order to obtain the axial stiffness of multi-layer expansion joints, the waveform parameters of the bellows are first designed, followed by theoretical calculations of the bellows' stiffness and analysis using structural simulation software, Combining stiffness tests, the influence of contrasting mesh elements, contact conditions, and wall thickness reduction on the equivalent stress and axial stiffness of multi-layer bellows was studied using the range analysis method. The law of the axial stiffness variation in the axial elastic and plastic stages of multi-layer expansion joints was also explored. The study demonstrates that under large compensation conditions, the impact of the three analyzed factors on equivalent stress varies with an increase in the number of layers. Setting appropriate simulation parameters can enhance the computational accuracy of multi-layer bellows stiffness, thereby facilitating precise prediction of bellows stiffness.

The need for high-performance optoelectronic functional materials has increased in recent years due to the expansion of the optoelectronic information sector. Potassium Titanium Oxygen Phosphate (KTiOPO₄,KTP) is internationally recognized as a material with excellent comprehensive optoelectronic performance. After periodic polarization, KTiOPO₄(PPKTP) can produce laser and entangled photon outputs of any wavelength within the crystal transmittance range using quasi-phase matching (QPM) technology, making it an ideal material for generating entangled photons for efficient frequency conversion and quantum communication. Its applications include laser manufacturing, quantum communication, electro-optical modulators, and optical waveguide devices. In this paper, the preparation of PPKTP crystal materials, the current status of development at home and abroad, and the applications in the quantum field are reviewed, and some challenges encountered in the preparation of the current hydrothermal PPKTP are also highlighted, and in future related research, the solution of these challenges is of great significance to improve the quality of the polarization reversal of the PPKTP and to promote the device's wider application.

In this paper, the aluminum metal thin layer protective layer with a micron-sized was pre-evaporated on the surface of the phosphating layer sample by vacuum thermal evaporation. The presence of a metal aluminum layer can effectively prevent the diffusion between the inlay and the phosphate layer during sample preparation. Moreover, due to the bright color of the metal aluminum layer under the optical microscope, a bright strip can be formed on the phosphating layer, which can accurately locate the end point of the thickness measurement under the metallographic microscope and improve the accuracy of the thickness measurement. It can be shown that the thickness of the surface phosphating layer is about 8.047μm. And the result meets the designed technical index of phosphating layer thickness (≤10μm). Furthermore, the test characterization method can also provide indirect evidence for the uniformity of the phosphating layer.

Damage is inevitable during the operation process of civil aircraft, composite material repair technology has been widely used in civil aviation.The repair parameters have an important effect on the reliability of the composite materials. Thus, in this paper, the laminates have been mending by different argument, and the influences of the lay-up lap size on failure strength, toughness, strain and measurement uncertainty on laminates has been investigated. The results shown that, with increased lay-up size, samples’ failure strength and measurement uncertainty was increased, toughness was decreased, the strain change tend of all samples was non repair area> edge of repair area> center of the repair area.

It is a tremendous challenge for the detection of target analyte without self-reporting optical, electronic, and magnetic signal and so on, in situ recognition site. Herein, a strategy for a synthesized artificial antibody (imprinted polymer microspheres, MIPs) microsphere with non-fluorescence tagged recognition site for the detection of ultra trace picric acid derivative with fluorescence-enabled self reporting in solution environments. Picric acid reacted with N, N'-diisopropyl carbodimide to generate the picric acid derivative 1 (PAD1) with bright yellow fluorescence and the picric acid derivative 2 (PAD2) without fluorescence, respectively. The artificial antibody with the performance of selective recognition and sensible detection were synthesized through the copolymerization with reaction of using PAD1 as template, acrylamide as functional monomer, ethylene glycol dimethacrylate as crosslinking agent and azodiisobutyronitrile as initiator in acetonitrile solution. The recognition sites of polymer microspheres eluting imprinted-PAD1 template molecules in microsphere surface have hollow cavities matching the spatial structure of template molecules. The in situ recognition sites of the microspheres were rebounded by trace PAD1 through the concentration difference driving force on the microsphere surface, the PAD1 target molecule with fluorescence- enabled self reporting in situ recognition sites was sensibly detected through the change of fluorescence intensity, thus the as-synthesized imprinted microspheres can efficiently and selectively identify and high sensibly detect the trace PAD1 in the solution environment.

Four AgCuO contact materials with different CuO contents were prepared using atomization technology. The electrical performance parameters of these four materials, including electrical life, welding force, arc energy, and arc burning time, were tested under AC250V and 25 A resistive load conditions using simulated electrical performance testing equipment. The test results and the surface arc erosion morphology of the contacts after the test were analyzed. Research has found that as the CuO content increases, the arc energy and arc time of the contact material gradually decrease, and the anti fusion welding performance gradually increases. Although it may lead to changes in the physical properties of the material, it greatly helps to improve the anti fusion welding performance of the material, thus reducing its impact on the material's performance; The addition of CuO is beneficial for suppressing material transfer and splashing. When the amount of CuO added is 15%, the surface burn morphology and electrical performance parameters of the material are better.

To figure out the effect of inorganic filler clay on the polyphenylene oxide (PPO) material, the PPO/clay composites were prepared via the extrusion process. The rheometer, scanning electronic microscopy (SEM), differential scanning calorimeter (DSC), thermogravimetic analysis (TGA), Vicat softening temperature, universal testing machine and the impact testing machine were applied for the analyses of rheology, morphology, thermal and mechanical performance of the composites. The glass transition temperatures (Tg) of the composites increased about 7 ℃ and the decomposition temperatures (T5%) increased about 5 ℃ with addition of clay upto 7.5 wt%. The Vicat softening temperature and flexural modulus increased with the increasing of clay content, while the melt viscosity, tensile elongation and impact performance decreased. By using KH550 or KH560 for the surface treatment of clay, the melt viscosity, SEM and tensile results confirmed the improved interaction of clay with PPO resin.

This study successfully synthesized nitrogen-doped carbon quantum dot nanomaterials (N-CQDs) using a one-step hydrothermal method at 200 ℃, with alanine and disodium ethylenediaminetetraacetate as foundational substances. The form, composition, structure, and fluorescence characteristics of the N-CQDs were thoroughly studied. The findings indicated that the fabricated N-CQDs had a small near-spherical particle size (1.83 nm), possessed a surface rich in amino, hydroxyl, and carboxyl, and exhibited high water solubility. The N-CQDs demonstrate strong photoluminescence properties and a broad fluorescence emission range (408–504 nm), indicating their potential for significant applications in the field of fluorescence sensing.

The porousCu₂O@g-C₃N₄ compounds were prepared by hydrothermal method in EG as one reducing agent and medium using copper acetate as Cu sources. The prepared specimens were detected by TEM, XPS, XRD, FL and UV/vis DRS. The empirical conclusion indicate that g-C₃N₄ are two-dimensional nanomaterials and Cu₂O was deposited into g-C₃N₄ between two different layers with a bang. The photocatalytic activity of Cu₂O@g-C₃N₄ was characterized depend on degradated organic dye MB driven by light xenon lamp. The empirical conclusion show photocatalytic activity of Cu₂O@g-C₃N₄ was intensified according the structure of p-n heterojunction that interfaced Cu₂O with g-C₃N₄. The rate of MB decomposition increased from 55.23 to 97.07% compare with unitary g-C₃N₄ photocatalyst. Organic dye MB decomposition rate was reduced from 97.07% to 95.69% for several recycling uses, therefore, Cu₂O@g-C₃N₄ shows higher catalytic ability and fixity. The photodegradation mechanism of Cu₂O@g-C₃N₄ was investigated due to the produced active substances in the photocatalytic organic dye MB system.

The growing threat of persistent environmental pollutants and microorganisms is prompting researchers to examine the potential of titanium dioxide (TiO₂)-based nanocomposites with highly efficient photocatalytic capabilities and antimicrobial properties. By compositing various nanomaterials, such as metal oxides or graphene, with TiO₂ nanomaterials, researchers can produce reactive oxygen species under visible light, which accelerates the decomposition of complex organic molecules and enhances the functional properties. Based on this, we synthesised TiO₂-based nanocomposites containing different ratios of copper oxide (CuO) nanoparticles by solid-phase and hydrothermal methods. Structural evaluation by X-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed that these nanocomposites exhibited uniform particle distribution, intact composition, and particle size within 30 nm. The photocatalytic efficacy of the TiO₂-based nanocomposites was evaluated using an aqueous methylene blue solution. The results demonstrated that the TiO₂-based nanocomposites with optimal CuO ratios exhibited a removal efficiency of over 90% for the pollutant. These results underline the potential of TiO₂-based nanocomposites for environmental and public health applications, highlighting their importance in promoting sustainable technologies and improving water quality worldwide, making them an important advance in the management of environmental and health-related pollutants.

The overall stiffness of the deep water jacket is small, with an inherent period close to the wave frequency, and has significant dynamic response characteristics. The resulting inertial force load is one of the external loads that cannot be ignored. At the same time, under the action of environmental loads such as wind, wave and flow, high-frequency and high-amplitude cyclic stress is easily generated at the pipe joints, which leads to fatigue failure of the structure. Compared with the traditional S-N curve method, the ECA evaluation technology takes into account the influence of initial defects and residual bearing capacity of structures with defects. Therefore, based on the ECA evaluation technology, combined with the dynamic response characteristics of deep water jacket, this paper proposes a set of ECA evaluation process suitable for deep water jacket. In this paper, taking a deep-water jacket platform as an example, the influence of the dynamic response of the platform is introduced, and the fatigue life of the structure is calculated. Compared with the traditional S-N curve method, the rationality of the method applied to engineering practice is verified.

Titanium has been wildly used in automobile industry. However, it is recognized as a typical material which is difficult to cut. Therefore, this work aims at the effect of modulation period number on the cutting force, temperature distribution and temperature variation. It can be concluded that the TiN/TiSiN coated tool with the modulation period number of 3 had the best performance at various cutting speed. This may provide a guidance for coating structure design.

This study aims to investigate the impact of various micro-meteorological factors on the type and quantity of ice accretion on overhead transmission lines through experimental analysis. In an artificial climate laboratory, meticulously designed experimental setups were employed to simulate ice accretion under diverse geographical and meteorological conditions. The experimental results reveal that temperature is a key influencing factor on the type of ice accretion on transmission lines, with higher densities of glaze ice forming near zero degrees Celsius, while lower temperatures favor the formation of lighter rime ice. Additionally, wind speed exhibits a significant influence on ice type, with higher wind speeds favoring the formation of denser glaze ice. Experimental investigations into ice accumulation indicate that the amount of ice accretion on transmission lines increases with higher wind speeds, median volume diameter of supercooled water droplets, and liquid water content, but decreases with rising ambient temperatures.

This research focuses on the finite element stress analysis and optimization design of the high-speed shaft of SQ35 type wire cutter. First, the static analysis was carried out through 3D modeling and finite element software, and the performance performance of the high-speed shaft under various working conditions was deeply explored, including data on deformation, equivalent strain and equivalent stress. Through detailed data analytics, the surface fatigue crack problem caused by continuous stress was found. Secondly, by establishing a response surface optimization model, 90 sets of data were calculated, and 10 sets of excellent data were selected for further analysis. Finally, through the optimization design, the deformation of the high-speed shaft was successfully reduced by 14.7%, which effectively improved the fracture of the shaft head.

In response to the Flexible Job Shop Scheduling Problem (FJSP) with consideration of equipment preventive maintenance, this paper proposes a discrete Jaya algorithm. The algorithm is initialized by randomly generating machine selection codes and operation processing order codes. Subsequently, it employs POX (Partially-Mapped Crossover) and MPX (Multi-Parent Crossover) methods for crossover and updating. Then, Pareto sorting is used to help identify non-dominated solutions that achieve a balance between multiple objective functions, generating a Pareto front that meets the output requirements. Following this, experiments are conducted, and the results of the proposed discrete Jaya algorithm are compared with those of the Genetic Algorithm (GA), Simulated Annealing Algorithm (SA), and Particle Swarm Optimization (PSO) to verify its performance in solving the makespan (Cmax). The results demonstrate that the discrete Jaya algorithm designed in this paper has achieved superior solutions in terms of Cmax, reflecting the algorithm's effectiveness and global optimization capabilities. Additionally, corresponding high-quality Gantt charts are provided.

In order to solve the problem of low control accuracy in traditional grasping operation path control methods, this paper proposes an automatic control method for mobile robotic arm grasping operation path based on Cosserat mechanics theory. This method first models the kinematics of the mobile robotic arm and determines the nodes of the grasping operation path based on the modeling results. Secondly, using the Cosserat mechanics theory, a path controller was constructed to achieve automatic control of the grasping operation path of the mobile robotic arm. The experimental results show that compared with traditional methods, the method proposed in this paper can significantly improve the automation control accuracy of the operation path of the mobile robotic arm. The values of its Spearman correlation coefficient and calibration ratio are closer to 1, thus achieving better results.

This paper proposes a method for cross-condition fault diagnosis of gears that combines the Convolutional Block Attention Module (CBAM) with subdomain adaptation networks. The channel submodule employs both the maximum pooling output and the average pooling output from the shared network. Similarly, the spatial submodule utilizes analogous outputs, which are pooled across the channel axis and then passed to convolutional layers. The advanced subdomain adaptation network enhances the functionality of the Deep Adaptation Network (DAN) by capturing precise information for each category, synchronizing the overall distributions of source and target domains, and coordinating the distributions of relevant subdomains. Through comparative experiments, our proposed method outperforms Convolutional Neural Networks (CNN), Deep Adaptation Network (DAN), and Deep Subdomain Adaptation Network (DSAN).

A regulating technique is presented and designed in the active vibration control of a cantilever beam in this paper. An active damping device(inertial actuator) is proposed and designed. A control system for the constructed inertial actuator is developed. The dynamic model of the cantilever beam system with the constructed inertial actuator system is established and analyzed. A PID controller is designed and analyzed. An experimental platform of the cantilever beam system is constructed to verify the effect of the inertial actuator and efficiency of the control algorithm. Experiments have shown that the vibration of the cantilever beam with the active damping device is significantly reduced, and the vibration decreased by approximately 50% compared to the original cantilever beam system.

Composite materials are extensively employed in aerospace and other engineering applications, and it is of tremendous practical importance to study the mechanical behaviours, such as damage accumulation and failure law of their material structures. In order to predict the load capacity and damage degradation of composite hat-stiffened panels under compressive load, numerical and experimental methods are employed to study four kinds of degradation models (sudden degradation model based on elastic constants, progressive degradation model based on elastic constants, constant degradation model based on CDM, linear degradation model based on CDM). Numerical simulations are conducted by using ABAQUS software. The estimated buckling and ultimate capacity agreed well with the data in experimental. The comparison shows that all four damage degradation models can predict the load-carrying capacity and damage range. Compared with the other models, the constant degradation model based on CDM has the highest accuracy. The results provide theoretical guidance for studying the mechanical properties of composite hat-stiffened panel under compressive load.

Aiming at the problems of manual measurement of key parameters of satellite rigid solar wing deployment, such as tedious, time-consuming, low efficiency, and high labor intensity for operators, based on the principle of multi-eye vision measurement, an automatic measurement system for key parameters of satellite solar wing deployment is constructed through multiple groups of vision measurement terminals. Based on the multi-level joint calibration technology, the coordinate system of each group of measurement terminals is unified; The target pasted on the solar wing panel of the satellite is directly photographed by multi-group vision measurement terminals, and the actual trajectory and image of the target are obtained. The key parameters of the solar wing deployment state are calculated by the incremental light speed adjustment method, and the measurement error analysis is carried out to meet the error accuracy requirements. Through the deployment test of the actual satellite rigid solar wing product, the efficiency is improved by more than 500% compared with the traditional manual measurement method, which proves the effectiveness of the method.

Accurate estimation of the state of charge is the cornerstone for battery management systems to achieve effective battery management and control. However, due to the challenging nature of directly measuring real-time SOC, it is typically obtained indirectly by processing external parameters. This paper introduces an innovative SOC estimation method called the VFFRLS-UKF algorithm in detail. Based on the classical Thevenin battery model, this algorithm first employs the variable forgetting factor recursive least squares (VFFRLS) algorithm for online model identification. The SOC is then accurately estimated in conjunction with the unscented Kalman filter (UKF). In order to verify the practicality and accuracy of the VFFRLS-UKF algorithm, a comprehensive validation was carried out under two working conditions, BBDST and DST, respectively.

Small-diameter branch pipes are crucial components of pressure vessels, with potentially serious consequences if they fail. Nondestructive testing of buried defects in fillet welds has been challenging in the industry. Presently, phased array nondestructive testing technology is commonly utilized, but further research is needed to characterize the defects accurately. The fillet weld model of the actual specifications of the small-diameter branch pipe of the pressure vessel was simulated and analyzed by the CIVA software in accordance with pressure vessel specifications. The echo response law and characteristics of typical defects such as spherical holes, transverse through holes, incomplete fusion, incomplete penetration, and cracks were studied. The results show that the echo intensity is different for various defects compared to the signal of the end corner structure. The echo intensity of area defects is greatest when they are at an angle of 90° to the sound beam. Echo intensity can vary considerably when the same type of defect is located at different positions, with a maximum difference of 13 dB. Simulated specimens with typical defects were designed and fabricated, and the testing results of five typical defects were analyzed. The results show that the defects in the specimen can be effectively detected. The changing patterns of echo characteristics of different defects, as summarized in this study, can provide a reference and basis for characterizing defects in field inspection.

The adhesion features between parallel wheels and rail may diverge heavily due to the eccentric abrasion and rail surface pollution, thus torque/speed asynchronization and wheel idling may occur frequently, finally result in system failure. In this paper, ring coupling strategy(RCS) is introduced to couple the adjacent creeping speed of parallel wheel-rail adhesion pairs, the differences are used as the accessional torque feedback of corresponding motor to avoid sliding phenomena. Firstly, the adhesion feature between wheel-rail pair and the system dynamic is analyzed. Subsequently, torque master salve strategy(TMSS) that parallel motors track the output of the auto speed regulator(ASR), which control the rotation velocity of the pedestal, is introduced and studied against parameters and adhesion feature deviation. Finally, the modified RCS are studied as contrast. The results indicate that, when the adhesion feature changes and the friction ratio couldn’t meet the requirement to follow the torque reference form ASR, the motor would slide heavily under TMSS and no longer acting as driver. Oppositely, RCS would adaptively adjust the motor to work at the critical adhesion point with proper creeping speed, and thus generate maximum driving torque of current adhesion feature.

Thin-walled workpieces,due to their unique structural properties, are extensively utilized in aerospace parts, and the severe vibration of thin-walled parts pose significant safety hazards to equipment operation. A method of controlling structural vibration of thin-walled workpiece with active damping device (ADD) is proposed,and the dynamic model of the actuator is built, the control principle of the controlled system are analysed based on the direct velocity feedback control algorithm (DVF), and an experimental bench of vibration suppression of thin-walled workpiece by the ADD is built and the vibration control effects of workpieces with varying excitation frequency, amplitude, and thickness are compared. The results show that the ADD has the characteristics of wide frequency band and good self-adaptive effect.The ADD can effectively suppress the vibration of thin-walled workpiece under different excitation frequencies with the maximum reduction of 34.03%,and it has control effects on workpiece vibration at different excitation force amplitudes, with a maximum reduction of 36.2%,can reduce the structural vibration of the workpiece with different thicknesses. The research provides new ideas for the vibration control of thin-walled workpieces and the design of active damping devices.

Aiming at the problem of non-contact explosion of mines and other shallow buried improvised explosive devices on protective structures, the *INITIAL_IMPULSE_MINE(IIM) algorithm based on the empirical model was used to numerically simulate the soil burial test rig and comparatively analyze the dynamic response of the target plate under the two algorithms of ALE and S-ALE. The simulation results show that, in terms of computational speed, the IIM algorithm, due to the absence of a flow field grid and the need for fluid-solid coupling processing, greatly increases the computational speed, which is only 6% and 8.7% of that of the ALE and S-ALE algorithms; however, in terms of computational accuracy, the IIM algorithm has the largest error relative to the other two algorithms, which reaches 20.3%.

Electrochemical deposition is often used for the high-quality preparation of metal microstructures. In the past mask electrodeposition, mass transfer in the microregion is difficult when the microstructure with a large height is prepared, and the microstructure forming quality is poor. In this paper, a processing method using trapezoidal anode to enhance the mass transfer ability of the confined microregion of electrodeposition is proposed. In this study, the deposition conditions under the condition of flat anode and trapezoidal anode were compared by simulation and experiment. The results consistently show that under the condition of trapezoidal anode, the metal microstructure roughness is significantly reduced, and the deposition rate is greatly improved, which well proves the enhancement of trapezoidal anode on the mass transfer capacity in the micro-region.

In the service process of oil and gas pipeline, due to high pressure, large deformation and other operating conditions, plastic damage will inevitably occur, and then fracture and failure will lead to leakage accidents.In order to evaluate the damage degree of pipeline steel and judge the service status, it is urgent to carry out the plastic damage detection technology of pipeline steel. This paper discusses the problem of plastic damage of X80 pipeline steel by simulation. The simulation model of nonlinear ultrasound mixing detection are verified with the experiment which was performed based on RITEC RAM-5000 SNAP, and the maximum absolute error was 0.3×10^-3. According to the finite element analysis of nonlinear mixing ultrasound, it is known that the nonlinear parameter β will increase with the increase of the degree of plastic damage of the material. Therefore, the nonlinear mixing ultrasonic signal can effectively represent the degree of plastic damage of X80 pipeline steel. The research results provide a technical way to further evaluate the remaining life of oil and gas pipeline.

In the perforating or drilling conditions, the high-speed liquid-solid two-phase flow will cause erosion damage to the pipe wall, resulting in thinning of the pipe, which will cause serious safety hazards to the oil and gas development and construction. In this paper, the liquid-solid two-phase flow is simulated by discrete particle two-phase numerical computation method to simulate the erosion of spiral flexing tubing, and the fluid motion characteristics, particle trajectory and inner wall erosion results are obtained under different pitch, different flow rate, different particle concentration and different particle size. The simulation results show that the erosion damage is mainly distributed in the vicinity of the helix, and the erosion rate gradually decreases with the increase of the pitch. With the increase of fluid velocity and particle concentration, the erosion rate increases. The effect of particle size on erosion is mainly reflected in the distribution of erosion and has a small effect on the extreme value of erosion rate. As the particle size increases, the kinetic energy of the particles increases, and the damage site is more concentrated on the outer side of the helix.

In response to the power balance issue in multi-motor drive systems of belt conveyors, this study proposes a control method based on the Back-propagation Neural Network (BPNN). This method effectively enhances the robustness and control accuracy of the system by simulating the functionality of the control system. This paper provides a detailed introduction to the construction process of the neural network model and verifies the feasibility and superiority of the proposed control strategy through simulation experiments using MATLAB software.

To address the issue of complex launch processes in hybrid transmission vehicles during race launches, a design was developed to evaluate the conditions for launch control. The design also includes the control flow design for launch control, which consists of five phases: C0 clutch control, motor control, and drivetrain mode control in the VCU and PCM during specific phases. Ultimately, real vehicle testing has demonstrated that the designed control flow can ensure torque demand from the driver, thereby enhancing driving performance and reliability of the vehicle.

For perovskite light-emitting diodes (PeLEDs), the instability of devices is one of the major obstacles toward commercial applications. Recently, high operational stability comparable to that of OLEDs has been demonstrated in near-infrared (NIR) PeLEDs. However, the stability of visible PeLEDs remains unsatisfactory and the mechanisms of degradation are not yet fully understood. Here, we systematically study the performance of PeLEDs based on different electron-transport layers (ETLs) and find that the deterioration of electron transport contributes to the degradation of PeLEDs. Further, time-of-flight secondary ion mass spectrometry results reveal the impaired electron injection layer during continuous operation. With PO-T2T as the ETL and CsF as the EIL (PO-T2T/CsF), we demonstrate a more balanced and robust electron transport. The resultant PeLED exhibits a maximum EQE of 17.5%, a high luminance of 3.6×10⁵ cd m^-2, and a decent stability (T₅₀) of ~70 h at an initial luminance (L₀) of 1000 cd m^-2, significantly improved compared to that based on the commonly used TPBi/LiF structure.

Quasi-two-dimensional (quasi-2D) lead halide perovskite materials have demonstrated remarkable potential as gain media for amplified spontaneous emission (ASE) and lasing. In recent years, significant progress has been obtained in reducing ASE thresholds and enhancing ASE stability for quasi-2D perovskites. The films with excellent surface morphology can effectively decrease the defect state density and suppress non-radiative recombination rates. However, achieving precise control over surface morphology remains challenging in minimizing optical losses for quasi-2D perovskite films. Here, we report a one-step solution-based approach to fabricate pinhole-free and ultra-smooth quasi-2D lead-bromide perovskite films by incorporating two types of short-chain organic cations, formamidinium (FA), and methylammonium (MA). The optimized perovskite film exhibits a roughness of ~1 nm and low scattering loss. Furthermore, improvements in crystal orientation enhance the crystalline quality of the samples. These merits promote ASE with an exceptionally low threshold of 4.0 μJ cm^-2 and a large exciton binding energy of 73.9 meV.

The epoxy resin insulators on the roof of high-speed train work in an outdoor environment for a long time, and the aging umbrella skirt edge will form a gap when it is hit by a hard object, and the broken umbrella skirt will reduce the creepage distance, which may induce a flashover fault and even cause the train power supply interruption. A model including defect location, defect shape and radial defect depth was constructed and its potential distribution was calculated. Calculation results show that, with the constant defect shape and defect area, the local electric field strength distortion is the largest when the defect location is in the first umbrella skirt at the high-voltage end; the local electric field strength distortion rate is higher than that of the crescent-shaped defect with the shape of the broken area being triangular with the defect location and defect area in constant. When the defect location and shape are in constant, the decrease in creepage distance and the distortion rate of electric field strength increase with the increase of radial depth of the defect. The calculation results can provide a reference for evaluating the influence of insulator defects on the electric field distribution.

The water seepage of the vault of the railway tunnel will distort the electric field distribution near the cantilever insulator, the continuous water column may directly bridge the vault and the high-voltage fittings, and the interruption of the catenary power supply may cause a large number of train delays. Therefore, it is necessary to analyze the influence of water seepage on the electric field distribution near the cantilever insulator. The leakage water of the vault is equivalent to a cylinder with a bottom diameter of 3mm, and a three-dimensional model including the vault, water column and cantilever insulator was constructed and the electric field distribution was calculated. The calculation results show that the continuous water column extending downward from the vault will distort the average electric field intensity of the residual air gap, and the increase of the length of the water column will increase the risk of arc bridging on the high-voltage side and the end of the water column of the cantilever insulator. The maximum field strength and field strength distortion rate of the surface of the cantilever insulator and the water column increase with the decrease of the distance between the insulator and the water column. With the increase of the air gap distance between the water column and the insulator, the spatial electric field distortion rate near the insulator decreases nonlinearly. The results of this paper can provide reference for the subsequent design and test verification of the vault seepage diversion channel.

Aiming at the issue of maintaining high stability and efficiency in complex wind conditions for large wind turbines, a FF+FB independent pitch reduction load control strategy based on LiDAR wind measurement reconstruction is proposed. Firstly, a wind speed reconstruction method based on the VMD-LSTM model is established. By data-driven mining of the spatiotemporal characteristics between the multi-point LiDAR wind measurement data and the equivalent wind speed estimation. Considering the influence of pitch angle on the external flow field and wind speed evolution, wind speed reconstruction is achieved to provide more accurate wind speed information for pitch control while reducing the number of pitch operations. Then, a FF+FB pitch control strategy is designed to compensate for wind speed disturbances in the dynamic wind field through feedforward braking. In the feedback control, the blade root load is fed back to the controller, and adaptive independent pitch control is implemented to reduce the load. Finally, a model of a 5MW wind power system was built on the Matlab/Simulink platform for simulation analysis and verification. The results show that compared to feedforward control and feedback control, the standard deviation of output power under FF+FB control is reduced by 23.8% and 22.7%, and the standard deviation of tower base torque and blade root flap torque is reduced by more than 14%. The proposed method can ensure the stability of unit output power under turbulent wind conditions and significantly reduce blade load.

This paper proposes an improved Deeplabv3+ based conveyor belt deviation detection method. Firstly, the backbone network of Deeplabv3+ is replaced with a more lightweight convolutional neural network, MobileNet_V3, which gives better performance on small sample datasets; secondly, GAM (Gradient-weighted Class Activation Mapping) attention mechanism is introduced into the ASPP (Atrous Spatial Pyramid Pooling) module of the original network, enabling it to have better detection accuracy on datasets with high similarity among data samples; finally, the Lovasz Loss loss function is used to replace the cross-entropy loss function of the original network, effectively improving the smoothness of the segmentation of the exposed part of the idler roller. Experimental results show that the improved GAM-Deeplabv3+ algorithm has increased the accuracy by 3.1% compared to the original algorithm, and the detection speed can reach 94.9 fps, meeting the accuracy requirements of the conveyor belt deviation detection task.