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Chinese Journal of Aeronautics 2024年第2期37卷 524-540页

作者： Xuan CUI Rui ZHAO min wan School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

Electrically Assisted Forming(EAF)technology has obvious advantages in material forming.To develop an effective constitutive model considering electrical effects,room temperature and electrically assisted quasi-static uniaxial tensile tests were conducted using ultrathin nickelbased superalloy plates with a thickness of 0.25 mm.The research focused on the two most widely recognized effects:the Joule thermal and the electric athermal effects.The mechanism of current action can be divided into two scenarios:one considering the Joule thermal effect only,and the other considering both effects simultaneously.Two basic constitutive models,namely the Modified-Hollomon model and the Johnson-Cook(J-C)model,were selected to be optimized through the classification of two different situations,and four optimized constitutive models were proposed.It was found that the J-C model with simultaneous consideration of the Joule thermal effect and electric athermal effect had the best prediction effect by comparing the results of these four models.Finally,the accuracy of the optimization model was verified by finite element simulation of the electrically assisted stretching optimization model.The results show that the constitutive model can effectively predict the temperature effect caused by the Joule heat effect and the athermal effect of current on the material.

关键词： Joule heating Elastoplasticity Plastic deformation Superalloys Constitutive models

Microstructure evolution and mechanical properties of brazing joint for ultra-thin-walled Inconel 718 considering grain size effect and brazing temperature

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Chinese Journal of Aeronautics 2024年第2期37卷 541-556页

作者： Rui ZHAO Yueshuai SONG Hui KANG min wan School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China Jiangxi Research Institute of Beihang University Jiangxi 330000China

The systematic investigation of the mechanical properties and microstructure evolution process of ultra-thin-walled Inconel 718 capillary brazing joints is of great significance because of the exceptionally high demands on its application.To achieve this objective,this study investigates the impact of three distinct brazing temperatures and five typical grain sizes on the brazed joints’mechanical properties and microstructure evolution process.Microstructural evolution analysis was conducted based on Electron Back Scatter Diffraction(EBSD),Scanning Electron Microscopy(SEM),X-Ray Diffraction(XRD),High-Resolution Transmission Electron Microscopy(HRTEM),and Focused Ion Beam(FIB).Besides,the mechanical properties and fracture behavior were studied based on the uniaxial tension tests and in-situ tension tests.The findings reveal that the brazing joint’s strength is higher for the fine-grain capillary than the coarse-grain one,primarily due to the formation of a dense branch structure composed of G-phase in the brazing seam.The effects of grain size,such as pinning and splitting,are amplified at higher brazing temperatures.Additionally,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture mode.The fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack path.Therefore,this study contributes significantly to the literature by highlighting the crucial impact of grain size on the brazing properties of ultra-thin-walled Inconel 718 structures.

关键词： EYWORDS Ultra-thin-walled structure Brazing Inconel 718 Grain size effect Brazing temperature

Vibration Control of A Flexible Marine Riser System Subject to Input Dead Zone and Extraneous Disturbances

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China Ocean Engineering 2024年第2期38卷 271-284页

作者： ZHOU Li wanG Guo-rong wan min School of Mechatronic Engineering Southwest Petroleum UniversityChengdu 610500China Energy Equipment Institute Southwest Petroleum UniversityChengdu 610500China National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu 610500China

An observer-based adaptive backstepping boundary control is proposed for vibration control of flexible offshore riser systems with unknown nonlinear input dead zone and uncertain environmental disturbances.The control algorithm can update the control law online through real-time data to make the controller adapt to the environment and improve the control precision.Specifically,based on the adaptive backstepping framework,virtual control laws and Lyapunov functions are designed for each subsystem.Three direction interference observers are designed to track the timevarying boundary disturbance.On this basis,the inverse of the dead zone and linear state transformation are used to compensate for the original system and eliminate the adverse effects of the dead zone.In addition,the stability of the closed-loop system is proven by Lyapunov stability theory.All the system states are bounded,and the vibration offset of the riser converges to a small area of the initial position.Finally,four examples of flexible marine risers are simulated in MATLAB to verify the effectiveness of the proposed controller.

关键词： adaptive backstepping control disturbance observer flexible marine riser input dead zone vibration control

Identification,Characterization,and Probiotic Potentials of Lactobacillus pentosus SF-1

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Journal of Ocean University of China 2024年第2期23卷 509-517页

作者： JIAO Lin LIANG Shufei CHU Ruixia wanG Wentao MAI Kangsen LIU ming wan min Key Laboratory of Aquaculture Nutrition and Feed Ministry of Agriculture&Key Laboratory of MaricultureMinistry of EducationCollege of FisheriesOcean University of ChinaQingdao 266003China Engineering Research Center of Mariculture Ministry of EducationOcean University of ChinaQingdao 266003China

In recent years probiotics have been considered as a potential substitution of antibiotics to control pathogens and treat infectious diseases in aquaculture.In the present study a strain of Lactobacillus pentosus,named as L.pentosus SF-1,was isolated from waters in aquaculture.The species identification of this strain was conducted by 16S rRNA sequence,and the physiological and biochemical characteristics of this strain were assessed.Furthermore,the virulence,antibiotic sensitivity,cell surface characteristics and acid/base-resistance of L.pentosus SF-1 were determined to evaluate the probiotic potentials of this strain.Specifically,L.pentosus SF-1 is sensitive to most common antibiotics,and no hemolysin was generated from it,indicating the safety of this strain to hosts.In addition,L.pentosus SF-1 was able to tolerate the artificial gastric juice at pH 3 for 4 h and the artificial intestinal fluid at pH 6.8 or 8.0 for 6 h.Moreover,the analysis of self-aggregation and the adhesion of L.pentosus SF-1 to organic solvents suggested a high potential of L.pentosus SF-1 to inhabit the hosts,which was confirmed by testing the colonization of L.pentosus SF-1 in germ-free zebrafish.Interestingly,L.pentosus SF-1 displayed a high bactericidal activity against several bacterial pathogens.Consistently,the incubation of L.pentosus SF-1 significantly promoted the expression of antimicrobial components in zebrafish,contributing to the protection of the fish from E.tarda infection in vivo.Taken together,the probiotic strain L.pentosus SF-1 could be applied as anti-infection reagent in aquaculture.

关键词： Lactobacillus pentosus probiotics antibiotics hemolysis cell surface characteristics bactericidal activity infection

Pre-compensation of Friction for CNC Machine Tools through Constructing a Nonlinear Model Predictive Scheme

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Chinese Journal of Mechanical Engineering 2023年第5期36卷 62-76页

作者： Qunbao Xiao min wan Xuebin Qin State IJR Center of Aerospace Design and Additive Manufacturing School of Mechanical EngineeringNorthwestern Polytechnical UniversityXi’an 710072China

Nonlinear friction is a dominant factor afecting the control accuracy of CNC machine tools.This paper proposes a friction pre-compensation method for CNC machine tools through constructing a nonlinear model predictive scheme.The nonlinear friction-induced tracking error is frstly modeled and then utilized to establish the nonlinear model predictive scheme,which is subsequently used to optimize the compensation signal by treating the friction-induced tracking error as the optimization objective.During the optimization procedure,the derivative of compensation signal is constrained to avoid vibration of machine tools.In contrast to other existing approaches,the proposed method only needs the parameters of Stribeck friction model and an additional tuning parameter,while fnely identifying the parameters related to the pre-sliding phenomenon is not required.As a result,it greatly facilitates the practical applicability.Both air cutting and real cutting experiments conducted on an in-house developed open-architecture CNC machine tool prove that the proposed method can reduce the tracking errors by more than 56%,and reduce the contour errors by more than 50%.

关键词： Nonlinear model predictive control Friction compensation P-PI controller Stribeck model

Microstructural evolution and mechanical properties of brazed IN718 ultrathin-walled capillary structure using different particulate reinforced filler alloy

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Chinese Journal of Aeronautics 2022年第3期35卷 550-564页

作者： Wenpeng HAN min wan Rui ZHAO Hui KANG Yuantong RAO School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China

The development of hypersonic precooled combined cycle engine provides a reliable power system for the future intercontinental navigation and reusable space orbital transportation.The compact heat exchanger precooler is the key component of the cooling cycle system,which provides efficient heat management for the hypersonic engine.This investigation mainly focused on the manufacturing process of precooler,and the typical structure of the precooler,ultrathin-walled capillary structure,was facilitated by the vacuum brazing using the particle reinforced composite filler alloy.The effects of different types and contents of the reinforced particle on the spreading behaviour,microstructural evolution,mechanical performance changes were investigated in detail.During the cooling process,the nucleation and growth of the c-Ni solid solution on the surface of the reinforced particles was the main reason for the microstructure homogenization.Compared to the Ni particles,the more obvious mechanical properties improvement could be achieved by using IN718 particles reinforced composite filler alloy.The tensile strength and elongation of the brazed ultrathin-walled structure present 9.36%and 47.27%higher than that using initial filler alloy.Moreover,the micro-hardness distribution result revealed that the reinforced particles reduced the overall micro-hardness of the brazed region,dispersed the eutectic structure and increased the hardness dispersion,which would reduce the stress concentration tendency and improve the structural properties.

关键词： Composite filler alloy Hypersonic Precooler Mechanical properties Ultrathin-walled structure Vacuum brazing

Nomogram prediction of vessels encapsulating tumor clusters in small hepatocellular carcinoma≤3 cm based on enhanced magnetic resonance imaging

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World Journal of Gastrointestinal Oncology 2024年第5期16卷 1808-1820页

作者： Hui-Lin Chen Rui-Lin He Meng-Ting Gu Xing-Yu Zhao Kai-Rong Song Wen-Jie Zou Ning-Yang Jia wan-min Liu School of Health Science and Engineering University of Shanghai for Science and TechnologyShanghai 200093China Department of Radiology The Third Affiliated Hospital of Shanghai Naval Military Medical UniversityShanghai 200438China Department of Radiology Tongji University Affiliated Tongji HospitalShanghai 200065China

BACKGROUND Vessels encapsulating tumor clusters(VETC)represent a recently discovered vascular pattern associated with novel metastasis mechanisms in hepatocellular carcinoma(HCC).However,it seems that no one have focused on predicting VETC status in small HCC(sHCC).This study aimed to develop a new nomogram for predicting VETC positivity using preoperative clinical data and image features in sHCC(≤3 cm)patients.AIM To construct a nomogram that combines preoperative clinical parameters and image features to predict patterns of VETC and evaluate the prognosis of sHCC patients.METHODS A total of 309 patients with sHCC,who underwent segmental resection and had their VETC status confirmed,were included in the study.These patients were recruited from three different hospitals:Hospital 1 contributed 177 patients for the training set,Hospital 2 provided 78 patients for the test set,and Hospital 3 provided 54 patients for the validation set.Independent predictors of VETC were identified through univariate and multivariate logistic analyses.These independent predictors were then used to construct a VETC prediction model for sHCC.The model’s performance was evaluated using the area under the curve(AUC),calibration curve,and clinical decision curve.Additionally,Kaplan-Meier survival analysis was performed to confirm whether the predicted VETC status by the model is associated with early recurrence,just as it is with the actual VETC status and early recurrence.RESULTS Alpha-fetoprotein_lg10,carbohydrate antigen 199,irregular shape,non-smooth margin,and arterial peritumoral enhancement were identified as independent predictors of VETC.The model incorporating these predictors demonstrated strong predictive performance.The AUC was 0.811 for the training set,0.800 for the test set,and 0.791 for the validation set.The calibration curve indicated that the predicted probability was consistent with the actual VETC status in all three sets.Furthermore,the decision curve analysis demonstrated the clinical benefits of our model for pati

关键词： Small hepatocellular carcinoma Vessels encapsulating tumor clusters Nomogram Magnetic resonance imaging Multicenter

Post-Synthetic and In Situ Vacancy Repairing of Iron Hexacyanoferrate Toward Highly Stable Cathodes for Sodium-Ion Batteries

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Nano-Micro Letters 2022年第1期14卷 182-193页

作者： min wan Rui Zeng Jingtao Meng Zexiao Cheng Weilun Chen Jiayu Peng Wuxing Zhang Yunhui Huang School of Mechanical Science and Engineering Huazhong University of Science and TechnologyWuhan 430074People’s Republic of China School of Chemistry and Environmental Engineering Wuhan Polytechnic UniversityWuhan 430023People’s Republic of China State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074People’s Republic of China

Iron hexacyanoferrate(FeHCF)is a promising cathode material for sodium-ion batteries.However,FeHCF always suffers from a poor cycling stability,which is closely related to the abundant vacancy defects in its framework.Herein,post-synthetic and in-situ vacancy repairing strategies are proposed for the synthesis of highquality FeHCF in a highly concentrated Na_(4)Fe(CN)_(6) solution.Both the post-synthetic and in-situ vacancy repaired FeHCF products(FeHCF-P and FeHCF-I)show the significant decrease in the number of vacancy defects and the reinforced structure,which can suppress the side reactions and activate the capacity from low-spin Fe in FeHCF.In particular,FeHCF-P delivers a reversible discharge capacity of 131 mAh g^(−1) at 1 C and remains 109 mAh g^(−1) after 500 cycles,with a capacity retention of 83%.FeHCF-I can deliver a high discharge capacity of 158.5 mAh g^(−1) at 1 C.Even at 10 C,the FeHCF-I electrode still maintains a discharge specific capacity of 103 mAh g^(−1) and retains 75% after 800 cycles.This work provides a new vacancy repairing strategy for the solution synthesis of high-quality FeHCF.

关键词： Iron hexacyanoferrate Cathode Vacancy repairing Sodium-ion batteries

On the superplastic deformation mechanisms of near-αTNW700 titanium alloy

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Journal of Materials Science & Technology 2022年第13期108卷 173-185页

作者： Lixia Ma min wan Weidong Li Jie Shao Xiaoning Han Jichun Zhang School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China AVIC Manufacturing Technology Institute Beijing 100024China

The new near-αTNW700 titanium alloy is a potential candidate material for high performance ultrasonic/hypersonic aircrafts,which is designed for short-term service at 700℃.This study systematically investigated the superplastic deformation microstructure evolution and mechanism of TNW700 alloy at different strain rates and true strains at 925℃.Results show that TNW700 alloy exhibits excellent superplastic behavior in a constant strain rate range of 0.0005-0.005 s^(-1) with elongation above 400%.The peak stress decreases with decreasing strain rate,which is related to the increase ofβ-phase volume fraction caused by the increase of thermal exposure time.In addition,significant strain hardening is observed in early-middle stage of superplastic deformation,and flow softening is followed in middle-late stage.To rationalize these complex flow behaviors,electron backscatter diffraction(EBSD)and high resolution transmission electron microscopy(HRTEM)were used to characterize the microstructure.Strain hardening is correlated to the synergistic effect ofβgrain growth,dislocation accumulation,silicide precipitate,and solid solution strengthening ofαphase.Continuous dynamic recrystallization(CDRX)induced the fragmentation of primaryαgrains in middle-late stage of superplastic deformation,and the refinement ofαgrains,the increase ofβphase volume fraction and dynamic dislocation recovery are main causes of high strain softening.In addition,EBSD and TEM observations confirmed texture randomization,fine equiaxed primaryαgrains and intragranular dislocation movement,indicating that grain boundary sliding(GBS)accommodated by dislocation sliding/climb is the dominant superplastic deformation mechanism of TNW700 alloy.

关键词： Near-αtitanium alloy Superplastic deformation Strain hardening and flow softening Microstructure evolution Deformation mechanisms

A Gaussian process regression‐based surrogate model of the varying workpiece dynamics for chatter prediction in milling of thin‐walled structures

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International Journal of Mechanical System Dynamics 2022年第1期2卷 117-130页

作者： Yun Yang Yang Yang Manyu Xiao min wan Weihong Zhang School of Mechanical Engineering Northwestern Polytechnical UniversityXi'anChina State IJR Center of Aerospace Design and Additive Manufacturing Northwestern Polytechnical UniversityXi'anChina School of Mathematics and Statistics Northwestern Polytechnical UniversityXi'anChina

Since the dynamics of thin‐walled structures instantaneously varies during the milling process,accurate and efficient prediction of the in‐process workpiece(IPW)dynamics is critical for the prediction of chatter stability of milling of thin‐walled structures.This article presents a surrogate model of the IPW dynamics of thin‐walled structures by combining Gaussian process regression(GPR)with proper orthogonal decomposition(POD)when IPW dynamics at a large number of cutting positions has to be predicted.The GPR method is used to learn the mapping between a set of the known IPW dynamics and the corresponding cutting positions.POD is used to reduce the order of the matrix assembled by the mode shape vectors at different cutting positions,before the GPR model of the IPW mode shape is established.The computation time of the proposed model is mainly composed of the time taken for predicting a known set of IPW dynamics and the time taken for training GPR models.Simulation shows that the proposed model requires less computation time.Moreover,the accuracy of the proposed model is comparable to that of the existing methods.Comparison between the predicted stability lobe diagram and the experimental results shows that IPW dynamics predicted by the proposed model is accurate enough for predicting the stability of milling of thin‐walled structures.

关键词： flexible workpieces Gaussian process regression in‐process workpiece dynamics milling stability proper orthogonal decomposition stability lobe diagram