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Augmentation-based discriminative meta-learning for cross-machine few-shot fault diagnosis

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Science China(Technological Sciences) 2023年第6期66卷 1698-1716页

作者： XIA PengCheng HUANG YiXiang WANG YuXiang liu ChengLiang LIU Jie State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China MoE Key Lab of Artificial Intelligence AI InstituteShanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical and Aerospace Engineering Carleton UniversityOttawa ON K1S 5B6Canada

Deep learning methods have demonstrated promising performance in fault diagnosis tasks.Although the scarcity of data in industrial scenarios limits the practical application of such methods,transfer learning effectively tackles this issue through crossmachine knowledge transfer.Nevertheless,the cross-machine few-shot problem,which is a more general industrial scenario,has been rarely investigated.Existing studies have not considered the cross-machine domain shift problem,which results in poor testing performance.This paper proposes an augmentation-based discriminative meta-learning method to address this issue.In the meta-training process,signal transformation is proposed to increase the meta-task diversity for more robust feature learning,and multi-scale learning is combined for more adaptive feature embedding.In the meta-testing process,limited labeled fault information is used to promote model generalization in the target domain through quasi-meta-training based on data augmentation.Furthermore,a novel hyperbolic prototypical loss is proposed for more discriminative feature representation and separable category prototypes by designing a hyperbolic decision boundary.Cross-machine few-shot diagnosis experiments were conducted using three datasets from different machines,namely,the bearing,motor,and gear datasets.The effectiveness of the proposed method was verified through ablation and comparison studies.

关键词： fault diagnosis few-shot learning meta-learning data augmentation cross-machine discriminative loss

On the leader-following exponential consensus of discrete-time linear multi-agent systems over jointly connected switching networks

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Control Theory and Technology 2023年第3期21卷 469-477页

作者： Tao liu jie Huang Shenzhen Key Laboratory of Control Theory and Intelligent Systems Southern University of Science and TechnologyShenzhen 518055GuangdongChina Shenzhen Research Institute The Chinese University of Hong KongShenzhen 518057GuangdongChina Department of Mechanical and Automation Engineering The Chinese University of Hong KongHong KongChina

The leader-following asymptotic consensus problem for general discrete-time linear multi-agent systems over jointly con-nected switching networks was solved about a decade ago.Recently,the leader-following exponential consensus was further established using the so-called Krasovskii-LaSalle theorem for a class of discrete-time linear switched systems.But this method involves some advanced concepts such as the weak zero-state detectability of some limiting system.In this paper,we offer a simpler solution to the leader-following exponential consensus problem for general discrete-time linear multi-agent systems over jointly connected switching networks.After converting the solvability of the problem to the establishment of the exponential stability for a class of discrete-time linear switched systems,we first show that this class of linear switched systems is uniformly completely observable.Then,we further conclude that the uniform complete observability for this class of linear switched systems implies the exponential stability for the same class of linear switched systems,thus leading to the solution of the leader-following exponential consensus problem.Moreover,our approach also gives rise to an explicit characterization of the exponential convergence rate of the leader-following consensus problem.

关键词： Leader-following consensus Exponential stabilization-Linear switched systems Discrete-time systems

Modelling and analysis of initial icing roughness with fixed-grid enthalpy method based on DPM-VOF algorithm

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Chinese Journal of Aeronautics 2022年第7期35卷 168-178页

作者： jie liu Peng KE Department of Civil Helicopter Research and Development China Helicopter Research and Development InstituteTianjin 300000China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China

Ice particles could form under the continuous impingement of incoming supercooled droplets in icing conditions,which will change the surface roughness to enhance the further heat and mass transfer during icing process.A fixed-grid porous enthalpy method based on the improved Discrete Phase Model(DPM)and Volume of Fluid(VOF)integrated algorithm is developed to solve the multiphase heat transfer problem to give more detailed demonstration of the formation of initial ice roughness.The algorithms to determine the criterion of transformation from DPM to VOF and the allocation of source items during transformation are improved to the general DPM-VOF algorithm.Two verification cases,namely two glycerine-solution droplets impact and single droplet freeze,are conducted to verify the accuracy and reliability of the enthalpy-DPMVOF method,where the simulation results match well with experiment phenomena.Ice roughness on a NACA0012 airfoil is precisely captured and the effects on convective heat transfer characteristics are preliminarily revealed.The results illustrate that the enthalpy-DPM-VOF method could successfully capture the characteristics of motion and the phase change process of droplet,as well as balance the calculation accuracy and efficiency.

关键词： Discrete phase model Fixed-grid porous enthalpy method Ice roughness Icing modelling Integrated algorithm Multiphase heat transfer Volume of fluid

A short review of antibacterial Cu-bearing stainless steel:antibacterial mechanisms,corrosion resistance,and novel preparation techniques

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Journal of Iron and Steel Research(International) 2024年第1期31卷 24-45页

作者： Shuai liu Han-jie Guo School of Artificial Intelligence Beijing Technology and Business UniversityBeijing100048China Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials University of Science and Technology BeijingBeijing100083China

Cu-bearing stainless steel is widely used in the fields of food,medical and household sanitary equipment because of its surface finish and corrosion resistance.However,the growth of bacteria on stainless steel leads to the formation of biofilms,which causes corrosion.Therefore,the antibacterial property of stainless steel is a worthy research topic.Reviews of breakthroughs in the field of corrosion resistance and antimicrobial properties are still lacking.Herein,due to the scarcity of publications on the antibacterial mechanisms and processing methods of antibacterial Cu-bearing stainless steel,we review the current state of relevant research and progress.The toxicity of Cu,corrosion resistance mechanism of stainless steel,and antibacterial mechanism and preparation method of antibacterial stainless steel are reported.In addition,alloying,surface modification and other methods are found to have limitations in balancing the toxicity and antibacterial properties of copper and the relationship between the antibacterial properties and corrosion resistance of Cu-bearing stainless steel.A new preparation method of antibacterial stainless steel associated with selective laser melting(SLM)is proposed.SLM is becoming a powerful additive manufacturing technology that can be used to manufacture customized and complex metals.The research status of SLM applied in antibacterial stainless steel preparation is described.Finally,the future research direction of Cu-bearing antibacterial stainless steel is discussed.

关键词： Cu-bearing stainless steel Antibacterial Processing Additive manufacturing Corrosion resistance

Poverty Reduction Effect of Adaptation to Climate Change: Empirical Evidence from China's Loess Plateau and Qinba Mountains

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Chinese Journal of Urban and Environmental Studies 2020年第3期08卷 102-115页

作者： LIU Jie liu Changyi International Business School Shaanxi Normal University Global Energy Interconnection Development and Cooperation Organization

Based on the micro-survey data of rural households in China’s Loess Plateau and Qinba Mountains, this paper empirically examines the poverty reduction effect and mechanism of adaptation to climate change. The research conclusions show that the adaptation actions can significantly reduce the poverty vulnerability of farmers, especially the future incidence of poverty in agricultural or poor households to a greater extent, which is characterized by a “pro-poor” effect.Adaptation actions can reduce poverty from two aspects: decreasing the expected income volatility(loss mitigation effect) and increasing the expected income level(opportunity effect), and the former is stronger than the latter. In the post-2020 period, China should enhance policy support in rural areas to adapt to climate change, improve the resilience of farmers’ livelihoods and climate change resilience of rural areas, and promote sustainable poverty reduction.

关键词： Poverty vulnerability disaster risk adaption actions sustainable poverty reduction

Physical-mechanical properties of sediments and their correlation with near seafloor seismic amplitude in the Liwan canyon area, northern South China Sea

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Acta Oceanologica Sinica 2023年第5期42卷 130-138页

作者： jie liu Lejun liu Ping Li Key Laboratory of Marine Geology and Metallogeny First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China Laboratory for Marine Geology Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao 266237China Marine Engineering Environment and Geomatic Center First Institute of OceanographyMinistry of Natural ResourcesQingdao 266061China

Before the implementation of offshore oil and gas exploitation,it is essential to understand the various factors that influence the stability of submarine sediments surrounding the project.Considering the factors such as cost and operability,it is not feasible to assess the physical-mechanical properties of sediments covering the entire region by borehole sampling.In this study,the correlation between near seafloor seismic amplitude and the mean shear strength of shallow sediments was explored using seismic and core testing data from the northern continental slope area of the South China Sea.Results showed that the mean water content of sediments in the layer up to 12 m below the seafloor(mbsf)gradually increased with increasing water depth,and the mean shear strength tended to decrease rapidly near the 1000 m depth contour.The near seafloor seismic amplitude could reflect the mean shear strength of sediments in the 12 mbsf layer under seismic frequency of 65 Hz and wave velocity of 1600 m/s.When the mean shear strength was greater than 10 kPa or the water depth was less than 1000 m,there was a significant linear positive correlation between mean shear strength and near seafloor seismic amplitude.Otherwise,there was a significant linear negative correlation between mean shear strength and near seafloor seismic amplitude.On the basis of these correlations,the pattern of shear strength was estimated from near seafloor seismic amplitude and mapped.The mean shear strength of sediments above 12 mbsf gradually decreased with increasing water depth in the continental slope area,whereas little change occurred in the continental shelf and the end of the canyon.Within the canyon area,the mean shear strength of sediments was characterized by larger values in both sides of the canyon walls and smaller values in the canyon bottom,which was consistent with the infinite slope stability theory.The study provides a method for using near seafloor seismic amplitude data to guide sediment sampling design,and presents a continuous da

关键词： shear strength near seafloor seismic amplitude correlation and estimation northern South China Sea

Rejuvenating the Immune System:Insights for Anti-Neurodegeneration Strategies

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Neuroscience Bulletin 2022年第1期38卷 107-109页

作者： jie liu Yan-Jiang Wang Department of Neurology Daping HospitalThird Military Medical UniversityChongqing400042China Chongqing Key Laboratory of Ageing and Brain Diseases Chongqing400042China Center for Excellence in Brain Science and Intelligence Technology Chinese Academy of SciencesShanghai200031China

Aging is the primary risk factor for various chronic disorders,especially neurodegeneration diseases,including Alzheimer’s disease(AD)and Parkinson’s disease(PD).It has been estimated that about one in ten individuals aged>65 are affected by AD,and this prevalence continues to increase with the aging of the population[1],causing a heavy burden on the family and society.As the aging population grows progressively around the globe,drug discoveries targeting the aging process have become a hot spot[2].

关键词： degeneration Immune diseases

Development and Control Strategy of Subsea All-Electric Actuators

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Journal of Ocean University of China 2022年第5期21卷 1133-1146页

作者： liu Peng SHEN Dagang BA Yaoji CAO Jinfeng LIU Jie WANG Lihui School of Mechanical and Automotive Engineering Qingdao University of TechnologyQingdao 266520China Shandong Meichen Industry Group Co. Ltd.Weifang 262200China

The development of subsea all-electric Christmas trees is an area of focus in the offshore oil industry worldwide.The main difficulties are associated with the development and control strategies for subsea all-electric actuators,which are the most criti-cal components of subsea Christmas trees.A single-motor-level fuzzy PID control with an integrated working condition detection mod-ule and a three-motor redundant-level deviation strategy with coupled joint synchronous control were proposed in this paper to real-ize the real time determination of algorithm parameters according to the working conditions,solve the rapid redistribution problems,and maintain the fast speed of the servo motor of the subsea all-electric tree valve actuator.A synchronous control electrical system was built,tested,and verified through simulation analysis.Test results show that the two redundant servo motors can still control the all-electric valve actuator and provide good synchronization control capabilities despite the failure of one servo motor,and the verti-cal and horizontal vibration values of the system are within reasonable ranges.The synchronous control strategy can be applied to the synchronous control problem of subsea all-electric production systems,which is of considerable importance for the development of subsea all-electric production systems.

关键词： subsea all-electric actuator redundant-level deviation strategy synchronous control model synchronous control strategy load shocks strong robustness

Kelp Fucoidans Facilitate Vascular Recanalization via Inhibiting Excessive Activation of Platelet in Deep Venous Thrombosis Model of Mouse

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Journal of Ocean University of China 2024年第2期23卷 550-556页

作者： SUN Taohua LIU Jie YAN Taishan CHEN Anjin ZHANG Fang Department of Clinical Drug Trials Qingdao Municipal HospitalQingdao 266100China Department of Pharmacy Qingdao Municipal HospitalQingdao 266100China

This study was carried out explore the mechanism underlying the inhibition of platelet activation by kelp fucoidans in deep venous thrombosis(DVT)mouse.In the control and sham mice,the walls of deep vein were regular and smooth with intact intima,myometrium and adventitia.The blood vessel was wrapped with the tissue and there was no thrombosis in the lumen.In the DVT model,the wall was uneven with thicken intima,myometrium and adventitia.After treated with fucoidans LF1 and LF2,the thrombus was dissolved and the blood vessel was recanalized.Compared with the control group,the ROS content,ET-1 and VWF content and the expression of PKC-βand NF-κB in the model were significantly higher(P<0.05);these levels were significantly reduced following treatments with LF2 and LF1.Compared with H_(2)O_(2)treated-HUVECs,combined LF1 and LF2 treatment resulted in significant decrease in the expression of PKC-β,NF-κB,VWF and TM protein(P<0.05).It is clear that LF1 and LF2 reduces DVT-induced ET-1,VWF and TM expressions and production of ROS,thus inhibiting the activation of PKC-β/NF-κB signal pathway and the activation of coagulation system and ultimately reducing the formation of venous thrombus.

关键词： kelp fucoidans LF1 LF2 deep vein thrombosis platelet