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    Information & Control
    Operating Performance Assessment of Flotation Process Based on Multi-source Heterogeneous Information
    Yan LIU, Qi-jie BU, Hong-chen ZHAO, Xin GUO
    2024, 45 (9):  1217-1226.  DOI: 10.12068/j.issn.1005-3026.2024.09.001
    Abstract ( 394 )   HTML ( 21)   PDF (1823KB) ( 119 )  

    In view of the coexistence of image information and process data information in flotation process and small differences among features of different operation state, a novel operating performance assessment method based on multi?source heterogeneous information and deep learning was proposed for flotation process. Firstly, a residual network (ResNet) is established to extract deep features with more discrimination from original images of different performance grades. Secondly, a stacked sparse performance?relevant autoencoders (SSPAE) model is proposed, which introduces the state level label into the model training to overcome the problem that the traditional autoencoder ignores the state?related characteristics. Furthermore, an image and data feature fusion model based on attention mechanism (AM) is established, and then the fused features are used as the inputs of the SoftMax classifier to train the operating performance assessment model, realizing the reasonable and effective utilization of the multi?source heterogeneous information. Finally, the flotation process data is used for simulation verification. The simulation results show that the proposed method is superior to other comparative methods, verifying its superiority in evaluating the operating performance of flotation processes.

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    Face Inpainting Model Based on Denoising Diffusion Probability Models
    Ji-hong LIU, Xi-xiong HUANG
    2024, 45 (9):  1227-1234.  DOI: 10.12068/j.issn.1005-3026.2024.09.002
    Abstract ( 311 )   HTML ( 15)   PDF (4524KB) ( 90 )  

    A face inpainting model based on the denoising diffusion probability model is proposed aiming at the problems of poor image quality, blurred repair edges, complex model, and difficult training of the mainstream face inpainting model after image inpainting. By improving the denoising diffusion probability model, the U-Net network structure in Guided?diffusion is adopted. The fast Fourier convolution is introduced into the network, and then the model is trained and tested on the CelebA-HQ high?definition face image dataset. The experimental results show that the improved denoising diffusion probability model can achieve a PSNR of 25.01 and a SSIM of 0.886 compared to the original image, when inpainting face images with random mask, both of which are better than the model before improvement and the existing face image inpainting model based on generative adversarial networks.

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    Improved WLS Ultra-wideband Positioning Algorithm Based on Error Factor
    Lin LIU, Yu-hao SONG
    2024, 45 (9):  1235-1243.  DOI: 10.12068/j.issn.1005-3026.2024.09.003
    Abstract ( 221 )   HTML ( 5)   PDF (1751KB) ( 46 )  

    In order to improve the positioning accuracy of ultra?wideband (UWB) in non?line of sight (NLOS) scenarios, an improved weighted least square (WLS) algorithm based on error factor was proposed in this paper. A one dimensional convolutional neural network (1DCNN) is trained by using ranging values and real?time channel impulse response (CIR) features to achieve accurate prediction of error factor. Based on the predicted error factor, the weighting matrix of improved WLS algorithm is designed, and different base stations are given reasonable weights to improve the UWB positioning performance in NLOS scenarios. Static and dynamic measured data are collected from the real environment to verify the performance of the improved WLS algorithm. The experimental results show that the improved WLS algorithm has similar positioning performance to the least square (LS) algorithm and WLS algorithm in the line of sight (LOS) scenarios. In the NLOS scenarios, the improved WLS algorithm is obviously better than the LS algorithm and WLS algorithm, and can effectively restrain the NLOS error.

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    Materials & Metallurgy
    Quasi-Static and Dynamic Deformation Behavior of Fe-11Mn-4Al-0.2C Medium-Mn Steel
    Yi FENG, De-liang ZHANG, Zhi-hui CAI, Guang-jie HUANG
    2024, 45 (9):  1244-1251.  DOI: 10.12068/j.issn.1005-3026.2024.09.004
    Abstract ( 320 )   HTML ( 5)   PDF (3256KB) ( 43 )  

    The evolution of plasticizing mechanism and mechanical properties of the Fe-11Mn-4Al-0.2C medium-Mn steel during deformation were compared in this paper. With the increase of strain rate (0.002~200 s-1), the trends of changes in yield strength and tensile strength for the medium-Mn steel are completely opposite. The yield strength increases from 507 MPa to 649 MPa, while the tensile strength decreases from 1 089 MPa to 876 MPa. The plasticizing mechanism of quasi?static loading is dominated by the strong TRIP (transformation?induced plasticity) effect. The plasticizing mechanism is dominated by the weak TRIP effect in the initial stage of dynamic loading, and the TRIP effect disappears and the plasticizing mechanism changes into the temperature rise softening effect and the TWIP (twinning?induced plasticity) effect in the later stage of dynamic loading. The dislocation motion rate in the initial stage of dynamic loading is much higher than that of quasi?static loading, which results in the higher yield strength of dynamic loading than that of quasi?static loading. With the increase of strain, the cumulative adiabatic temperature rise inhibits the martensitic transformation and reduces the work?hardening capacity under dynamic loading, while the high hardness martensite is produced continuously under quasi?static loading, which results in the tensile strength of quasi?static loading higher than that of dynamic loading.

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    Optimization Study on Protrusion Length of Delivery Tube in EIGA Based on CFD
    Kuai-kuai GUO, Jian-zhong LI, Chang-sheng LIU
    2024, 45 (9):  1252-1257.  DOI: 10.12068/j.issn.1005-3026.2024.09.005
    Abstract ( 318 )   HTML ( 2)   PDF (3849KB) ( 45 )  

    A computational fluid dynamics (CFD) approach was developed to simulate the EIGA (electrode induction melting gas atomization) with different protrusion lengths of delivery tube. The effect of the protrusion length of delivery tube on the flow field structure and powder particle size was analyzed. The results show that when the protrusion length is 0 mm, the maximum velocity in the recirculation zone is 335 m/s, and the expansion wave cluster at the gas outlet increased significantly, resulting in backflow phenomenon. With the increase of the protrusion length (1~4 mm), the length of the recirculation zone gradually increases, and the average particle size of the alloy powder prepared first decreases and then increases. The maximum suction pressure is achieved at 2 and 3 mm of protrusion length of delivery tube, which is beneficial to the secondary fragmentation of liquid droplets. When the protrusion length is 2 mm, the particle size distribution of the powders shows a normal distribution, and the median diameter (d50) of the powders is 84 μm, which is the most uniform particle size distribution and the narrowest particle size range.

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    Mechanical Engineering
    RBF Neural Network Compensation Sliding Mode Control Strategy for Flexible Space Manipulators
    Xiao-peng LI, Jia-xing FU, Hai-long LIU, Meng YIN
    2024, 45 (9):  1258-1267.  DOI: 10.12068/j.issn.1005-3026.2024.09.006
    Abstract ( 375 )   HTML ( 3)   PDF (3206KB) ( 67 )  

    Flexible structures cause the dynamic parameters of flexible space manipulators to change with time, which reduces the accuracy of tracking control. The lighter mass and the larger ratio of length to radius may result in the vibration of flexible space manipulators during their movement. To solve the above problems, a dynamic model of a flexible space manipulator considering two?dimensional deformation and disturbance torque is established, and a simplified non?linear dynamic formula is derived. On this basis, a control law is designed to identify and compensate for the time?varying term and disturbance torque in the flexible space manipulator using the radial basis function (RBF) neural network. Then, using the hyperbolic tangent function as the approximation rate, a sliding mode control strategy is proposed. Finally, through simulation and ground physical prototype experiment, it can be concluded that in the design of control laws for flexible space manipulators, the control strategy with neural network compensation effectively reduces the impact of disturbance torque on the flexible space manipulator. By using the tanh function instead of the sgn function, the fluctuation of input torque can be reduced, and the effectiveness of the RBF neural network compensation sliding mode control strategy is verified.

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    Analysis of Influence of Assembly Process Parameters on Mechanical Properties of Bolted Joint with Spigots
    Zhong LUO, Yong-heng LUO, Xin XIONG, Fa-yong WU
    2024, 45 (9):  1268-1276.  DOI: 10.12068/j.issn.1005-3026.2024.09.007
    Abstract ( 348 )   HTML ( 1)   PDF (2635KB) ( 47 )  

    The bolted joint with spigots of the aero?engine rotor system is taken as the research object, and the non?linear characteristics of the bending stiffness of the single bolted joint are analyzed. The bending stiffness of the bolted joint is analyzed by ANSYS, and the influence laws of such assembly process parameters as the bolted joint with or without a spigot, the initial preload of bolts, bolt diameter, and the interference of the spigot on the joint bending stiffness are discussed. The influence of the spigot on the inherent characteristics of the aero?engine rotor system is analyzed. The results show that the bending stiffness of the joint with the spigot presents piecework characteristics. Increasing preload of bolts, the bolt diameter and the interference of the spigot can improve the bending stiffness of the bolted joint. The relative error of the first three order natural frequency is less than 2% for rotor system with or without spigots. The bolted joint with spigots can reduce the maximum vibration amplitude of the rotor system.

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    Dynamic Modeling and Stress Reduction Optimization of Series Pipelines Based on Pipe-Solid Element Coupling
    Fang-ming LIU, Wei SUN
    2024, 45 (9):  1277-1286.  DOI: 10.12068/j.issn.1005-3026.2024.09.008
    Abstract ( 299 )   HTML ( 2)   PDF (3560KB) ( 32 )  

    To handle the urgent need for vibration reduction of spatial series pipelines, a finite element modeling method for spatial series pipelines based on pipe?solid elements coupling was proposed, and on this basis, the clamp layout optimization with the goal of reducing stress response was performed. The modeling concept is described in detail, that is, the regions with high stress, such as clamps and pipe joints, are modeled by solid elements, the other regions are modeled by pipe elements, and finally the parts are coupled together to complete the overall modeling. A specific optimization model is created, and the process of optimization using the genetic algorithm is given. A typical series pipeline is taken as the object for a case study, and the rationality of the model is verified by simulation and experiment. Stress reduction optimization is performed, the optimal clamp layout of the system is obtained, and the maximum resonance stress of the optimized system fundamental frequency was reduced by 27.05% compared with the initial state.

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    State Estimation Method Based on Improved VINS-Mono Algorithm
    Hai-fang WANG, Ding-jie QIAO, Tian-hao WU, Peng HUANG
    2024, 45 (9):  1287-1293.  DOI: 10.12068/j.issn.1005-3026.2024.09.009
    Abstract ( 285 )   HTML ( 2)   PDF (1067KB) ( 38 )  

    Aiming at the requirement of precision in pose recognition process of traditional SLAM(simultaneous localization and mapping), the reverse optical flow algorithm is added to the front?end part of VINS-Mono. To meet the real?time requirement of SLAM, a marginal optimization algorithm is integrated into the back?end sliding window optimization method of VINS-Mono, the parts excluding camera pose are marginalized firstly, and then pose parts of cameras are marginalized, to accelerate marginalization process. And experiments are carried out using EuRoc(European robotics challenge)datasets. The results show that accuracy is improved slightly by improvement strategy of the front end, and the possible reasons are analyzed. For the improvement strategy of the back end, it is found that compared with the source code, the time used for the marginalization of the improved algorithm is reduced by 25.9% on average, and then compare their trajectory accuracy. It is found that the error is controllable. Finally, it is verified that the improved strategy for the back?end of VINS-Mono is superior in real?time performance.

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    Parameter Analysis and Verification of Variable F-RD-Type Lattice Structure
    Bo HAO, Peng ZHANG, Zhi-ming ZHU
    2024, 45 (9):  1294-1300.  DOI: 10.12068/j.issn.1005-3026.2024.09.010
    Abstract ( 218 )   HTML ( 0)   PDF (4059KB) ( 27 )  

    Aiming at the conventional F-RD-type lattice structure for deformation design, a TPMS parameter design method based on implicit expression is proposed to design the lattice structure by changing the deformation parameter inputted into the implicit expression; the influence law of the deformation parameter and the threshold value on the porosity of the F-RD-type lattice structure is investigated, the single parameter and mixed parameter methods for porosity analysis are proposed, the mapping relationship between the deformation parameter and the threshold value on the variable F-RD-type lattice structure is established, and the F-RD-type lattice structure with specific shapes and porosity can be generated; through the AlSi10Mg samples prepared by the metal laser sintering molding principle, the influence relationship of the deformation parameter and the threshold value on the actual porosity is verified, which provides a reference for the engineering design and application of TPMS lattice structures.

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    Formation of White Layer on the Grinding Surface of Ni-Based Single Crystal Superalloy
    Yun-chao XU, Ya-dong GONG, Jin-min TIAN, Wei-jian ZHANG
    2024, 45 (9):  1301-1308.  DOI: 10.12068/j.issn.1005-3026.2024.09.011
    Abstract ( 295 )   HTML ( 0)   PDF (3677KB) ( 40 )  

    Surface integrity is very important to the service performance and lifespan of parts, but research of the microstructure evolution mechanism of single crystal superalloy during machining is still lacking. The grinding force and temperature of single crystal superalloy were collected, and the microstructure changes and microhardness on the grinding subsurface were characterized. The characteristics of the white layer were studied as well. The results showed that in the range of test parameters, the grinding force and temperature increase remarkably with the grinding depth increasing, and the thickness of the white layer and the plastic deformation layer increases with the increase of grinding depth and feed speed. The element diffusion is found between the white layer and the plastic deformation layer, resulting in rich Al and Ta elements in the white layer. The surface microhardness increases after grinding, and the hardening degree rises with the increase of grinding depth and feed speed.

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    Influence of Shock Wave Structure on the Ejector’s Operating Characteristics
    Yu HAN, Xiao-dong WANG, Peng-fei LI, Guang-li ZHANG
    2024, 45 (9):  1309-1316.  DOI: 10.12068/j.issn.1005-3026.2024.09.012
    Abstract ( 326 )   HTML ( 1)   PDF (1562KB) ( 31 )  

    An ejector refrigeration recycle system can not only save energy and protect the environment but also realize recycling because it uses water as the working medium. The structure of the shock wave inside the ejector, i.e. , the core component of the system, is discussed and divided in detail by numerical simulation. The determination basis of the pseudo?shock region, constant velocity region, oblique shock region and positive shock region is given for the first time. The influence of shock wave structure on the ejector’s operating characteristics is discussed. The results indicate that the position of positive shock wave is affected by the outlet back pressure. The pseudo?shock region is the direct factor that determines the ejector’s entrainment ratio. Shock train is important in reducing the flow velocity and restoring pressure in the ejector. The presence of a shock?mixing layer separates the working steam from the flow path of the ejecting steam. The working steam passes through the shock?mixing layer to carry and accelerate the flow of the ejecting steam. The area of the shock?mixing layer is affected by the ejector’s geometry and the working conditions of the working steam. Therefore, understanding and mastering the structure of shock waves is of reference value to understand the internal fluid flow law of the ejector, to improve the working efficiency of the ejector, and to further improve and optimize the ejector’s geometry.

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    Resources & Civil Engineering
    Implicit 3D Integrated Modeling of Complex Geological Structures in Mining Areas
    Zhi-bin LIU, Jian-qiao ZHANG, Xiao-feng DU, Jia-teng GUO
    2024, 45 (9):  1317-1325.  DOI: 10.12068/j.issn.1005-3026.2024.09.013
    Abstract ( 318 )   HTML ( 5)   PDF (5793KB) ( 49 )  

    The implicit modeling method offers the advantage of automating the modeling process and has been successfully applied to automatic modeling of shallow geological formations. However, the automatic integrated modeling remains challenging for mine areas with multiple deep and complex geological formations such as intrusive rocks, faults and goaf. Based on the HRBF implicit modeling method, this paper proposes the implicit modeling feature vector extraction method for the coal seam, intrusive rocks, goaf, faults and other structures in the mining area, and designs the implicit integration method between the structural model and the strata model, enabling the topology?consistent integrated modeling of complex geological formations in the coal mine area. A case study of Jinan Subway Line 8 shows that this method can realize the implicit modeling of intrusive rocks, gobs and faults, which provides auxiliary support for decision?making and ensures safety in the construction of urban rail transit projects.

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    Extraction of Road Point Cloud in Open Pit Based on Multi-feature Constraints
    Ya-chun MAO, Zhe-xi YANG, Wang CAO, QI Ji
    2024, 45 (9):  1326-1333.  DOI: 10.12068/j.issn.1005-3026.2024.09.014
    Abstract ( 233 )   HTML ( 2)   PDF (4906KB) ( 27 )  

    Aiming at the problem that road point cloud data in open pit is difficult to be accurately extracted through point cloud features such as normal vector and kerb, a method of road point cloud extraction in open pit with multi?feature constraints was proposed. Taking the laser point cloud in the open pit of Qianshan limestone mine in Liaoyang City as the data source, the original data was downsampled firstly, and then the training set and verification set were made and divided based on the five kinds of point cloud features including single point RGB information, neighborhood RGB information, neighborhood height difference, neighborhood roughness, and reflection intensity. The road point cloud extraction model was constructed and optimized using the random forest algorithm. Furthermore, European clustering algorithm was introduced to improve the road point cloud extraction model. Finally, the road point cloud extraction results were evaluated in open pit. The results show that the proposed method can effectively and accurately extract the road point cloud data in open pit in real time.

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    Experimental Study on Accelerative Characteristics of Syngas Laminar Premixed Flames
    Hao-ran ZHAO, Gang LI, Jin-hua WANG, Zuo-hua HUANG
    2024, 45 (9):  1334-1341.  DOI: 10.12068/j.issn.1005-3026.2024.09.015
    Abstract ( 302 )   HTML ( 0)   PDF (1717KB) ( 62 )  

    A systematic investigation on accelerative characteristics of syngas laminar premixed flames is conducted using the visual experimental platform of constant volume combustion chamber. The decoupling control of self?instability is realized by adjusting the equivalence ratio and oxygen?nitrogen ratio of gas mixture, allowing for an analysis of flame acceleration stages, onsets, and acceleration exponents. Three distinct stages of laminar flame propagation outwardly are identified, namely quasi?steady, transitional acceleration, and saturated acceleration. The order of four onsets is as follows: crack branching≈transitional acceleration<uniform cellularity≈saturated acceleration. The acceleration exponents in saturated acceleration stage are in the range of 1.1~1.2, showing independent on Lewis number and density ratio. The results indicate that the flame intrinsic instability can have a significant promotion on the onset of laminar flame acceleration, while it does not affect the flame acceleration strength in saturated acceleration stage.

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    Removal Effect of Organics in Reverse Osmosis Concentrate of Municipal Wastewater by Ozone Catalytic Oxidation
    Yu XIA, Jing LIU, Xu-wen HE, Hong-ying YANG
    2024, 45 (9):  1342-1351.  DOI: 10.12068/j.issn.1005-3026.2024.09.016
    Abstract ( 307 )   HTML ( 0)   PDF (3866KB) ( 64 )  

    To effectively remove the organics in municipal wastewater reverse osmosis concentrate (ROC) and understand their removal characteristics, the performance of ozone catalytic oxidation in the treatment of municipal wastewater ROC was studied based on measurements of conventional wastewater quality indices, analyses of relative molecular mass classification and hydrophobic/hydrophilic properties of organic matters, and methods of chromatography?mass spectrometry and electron paramagnetic resonance spectroscopy. The results indicate that the optimal treatment conditions are a reaction time of 80 min, an ozone mass concentration of 17 mg/L, and a raw wastewater pH of 7.3. The removal efficiencies of chemical oxygen demand (COD), UV absorbance at 254 nm wavelength (UV254), large?molecule organics (>30 ku) and hydrophilic acid component (HOA) are 55.75%, 85.05%, 95.46%, and 72.06%, respectively. Refractory organics such as aromatic hydrocarbons and humic acids, as well as pharmaceutical and personal care products (PPCPs) can be efficiently removed. Active substance·OH is generated. The data of COD degradation can be well described by a second?order reaction kinetics model.

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    Management Science
    Impact of Product Sharing on Dual-Channel Supply Chain
    Dao-gang QU, Bo XU, Cong GAO
    2024, 45 (9):  1352-1359.  DOI: 10.12068/j.issn.1005-3026.2024.09.017
    Abstract ( 367 )   HTML ( 0)   PDF (846KB) ( 29 )  

    A dual?channel supply chain model with its product sharing platform is developed. Based on the analysis of consumers’ purchasing decisions and product sharing decisions, the equilibrium of the model is obtained by adopting the game theory method. The changes in product prices, purchasing demands, and supply chain members’ profits in the dual?channel supply chain are compared between the two cases of non?product sharing and product sharing. Finally, numerical examples of the relevant results are conducted. It is found that product sharing decreases the profits of both manufacturers and retailers in the dual?channel supply chain. However, product sharing is beneficial to consumers, who actively participate in product sharing. Furthermore, the existence of product sharing can reduce product idleness and increase product utilization, which is beneficial to building a resource?saving society.

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    E-Closed-Loop Supply Chain Decision-Making Considering Government Regulation and Second-Hand Markets
    Chun-yu BAI, Zhi-min GUAN, Ying ZHAO, Jing-yang DONG
    2024, 45 (9):  1360-1368.  DOI: 10.12068/j.issn.1005-3026.2024.09.018
    Abstract ( 269 )   HTML ( 0)   PDF (1124KB) ( 26 )  

    The E-closed?loop supply chain decision?making consisting of a manufacturer and an e?commerce platform under government regulation are considered when the e?commerce platform opens the second?hand market or not, respectively, and the impacts of government disposal fund, subsidy rate, quality of used products, and commission rate of the platform on the manufacturer’s and e?commerce platform’s decision?making and expected profits are analyzed. It is found that when the second?hand market is open, the manufacturer’s optimal selling price for new products and optimal recycling price for used products are lower, and the e?commerce platform tries harder to sell new products. When the second?hand market is not open, the manufacturer’s expected profit is higher and the e?commerce platform’s expected profit is lower. Under government regulation, an increase in the disposal fund provides an incentive to the manufacturer to recycle used products and adversely affects the manufacturer’s production of new products, whereas an increase in the subsidy rate promotes the recycling of used products and does not affect the production of new products.

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