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Journal of Magnesium and Alloys 2024年第5期12卷 1815-1829页

作者： Eunji song Mohsen Taheri Andani Amit Misra Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA

In situ tensile testing in a scanning electron microscope(SEM)in conjunction with high-resolution electron backscatter diffraction(HR-EBSD)under load was used to characterize the evolution of geometrically necessary dislocation(GND)densities at individual grain boundaries as a function of applied strain in a polycrystalline Mg-4Al *** increase in GND density was investigated at plastic strains of 0%,0.6%,2.2%,3.3% from the area including 76 grains and correlated with(i)geometric compatibility between slip systems across grain boundaries,and(ii)plastic *** develop expressions for the grain boundary GND density evolution as a function of plastic strain and plastic incompatibility,from which uniaxial tensile stress-strain response of polycrystalline Mg-4Al are computed and compared with experimental *** findings in this study contribute to understanding the mechanisms governing the strain hardening response of single-phase polycrystalline alloys and more reliable prediction of mechanical behaviors in diverse microstructures.

关键词： Mg-Al alloys Grain boundaries Geometrically necessary dislocations Strain gradient plasticity HR-EBSD

Mechanism and experimental study on the fruit detachment of Chinese wolfberry through reciprocating vibration

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International Journal of Agricultural and Biological Engineering 2024年第2期17卷 47-58页

作者： song Mei Jinpeng Wang Zhiyu song Dunbing Tang Cheng Shen College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Nanjing Research Institute for Agricultural Mechanization Ministry of Agriculture and Rural AffairsNanjing 210014China Nanjing Forestry University Nanjing 210037China

In order to realize the efficient and high-quality mechanical picking for Chinese wolfberry,firstly,the forced reciprocating vibration picking principle of the Chinese wolfberry branch was studied,and the mechanical model of vibration picking was established based on the simplified cantilever model,and the response analysis and solution of all positions for the branch were carried *** the same time,the critical mechanical model of fruit detachment under the condition of fruit hanging on branches was established,and the theoretical values of inertia force for each component of the branch were ***,through actual measurement and finite element modeling,the natural frequency and forced vibration response simulation for each component of the branch of Chinese wolfberry terminal branch model were both studied,and the relationship between single-point periodic excitation force and high-quality fruit shedding parameters was ***,according to the conclusion of the picking model,a test bench with many groups of adjustable parameters was ***,the last branch of fruit-hanging Chinese wolf berry for Ningqi No.1 was taken as the experimental object,a four-level orthogonal experiment was designed with three factors:frequency,amplitude and entrance ***,the net picking rate,damage rate and false picking rate were taken as the evaluating indicators,referring to the comprehensive scores of the three *** was concluded that the primary and secondary relations of factors affecting the picking effect are frequency,amplitude and entrance angle,and the best operation parameters are frequency of 20 Hz,amplitude of 15 mm,and entrance angle of 45°,then,a hand-held vibration picker with setting parameters was trial-produced,and the optimal parameter combination was verified in the Chinese wolfberry planting base of the National Chinese wolfberry Engineering and Technology Research *** results showed that the net picking rate of rip

关键词： Chinese wolfberry branches reciprocating vibration inertial force orthogonal experiment

Dynamic Constraint-Driven Event-Triggered Control of Strict-Feedback Systems Without Max/Min Values on Irregular Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 569-580页

作者： Zhuwu Shao Yujuan Wang Zeqiang Li Yongduan song the State Key Laboratory of power Transmission Equipment&System Security and New Technology and the School of AutomationChongqing UniversityChongqing 400044China IEEE

This work proposes an event-triggered adaptive control approach for a class of uncertain nonlinear systems under irregular *** the constraints considered in most existing papers,here the external irregular constraints are considered and a constraints switching mechanism(CSM)is introduced to circumvent the difficulties arising from irregular output *** on the CSM,a new class of generalized barrier functions are constructed,which allows the control results to be independent of the maximum and minimum values(MMVs)of constraints and thus extends the existing ***,we proposed a novel dynamic constraint-driven event-triggered strategy(DCDETS),under which the stress on signal transmission is reduced greatly and no constraints are violated by making a dynamic trade-off among system state,external constraints,and inter-execution *** is proved that the system output is driven to close to the reference trajectory and the semi-global stability is guaranteed under the proposed control scheme,regardless of the external irregular output *** also verifies the effectiveness and benefits of the proposed method.

关键词： Adaptive control dynamic constraint-driven event-triggered control irregular output constraints nonlinear strict-feed-back systems

Dietary Macleaya cordata extract supplementation improves the growth performance and gut health of broiler chickens with necrotic enteritis

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Journal of Animal Science and Biotechnology 2024年第1期15卷 374-395页

作者： Bochen song Jie He Xue pan Linglian Kong Chuanpi Xiao Chake Keerqin Zhigang song Key Laboratory of Efficient Utilization of Non‑Grain Feed Resources College of Animal Science and TechnologyShandong Agricultural UniversityTaian 271018ShandongChina Center for Mitochondria and Healthy Ageing College of Life SciencesYantai UniversityYantai 264005ShandongChina precision Livestock and Nutrition Unit University of LiègeGembloux Agro‑Bio TechGemblouxBelgium phytobiotics(Jiangsu)Biotech Co. Ltd.Jintan 213200China

Background The poultry industry needs effective antibiotic alternatives to control outbreaks of necrotic enteritis(NE)caused by Clostridium *** The aim of this study was to investigate the effects of dietary supplementation with Macleaya cordata extract(MCE)on the immune function and gut microbiota of broilers with NE.A total of 2881-day-old broiler chicks were randomly assigned to a 2×2 factorial arrangement with two concentrations of dietary MCE supplementation(0 or 350 mg/kg of diet)and two disease challenge statuses(control or NE).Results The results revealed that NE significantly increased the feed conversion rate(FCR),mortality,intestinal lesion score,the levels of IL-1β,IL-17 and IFN-γ/IL-4 in serum and IL-17/IL-10 in the jejunal mucosa,m RNA levels of TLR2,IFN-γand p Ig R in the jejunum,and Clostridium perfringens concentrations in the *** significantly decreased the body weight(BW),body weight gain(BWG),jejunal villus height,V/C,m RNA level of AMpK-α1 in jejunum,IL-4 level in the jejunal mucosa and lactic acid bacteria abundance in the *** significantly increased BW,BWG,jejunal villus height,V/C,m RNA levels of occludin,ZO-1 and AMpK-α1 in the jejunum,the levels of Ig A and Ig G in serum and IL-10 in the jejunal mucosa and m RNA levels of NF-κB,IL-10 and MHC-II in the ***,MCE significantly decreased the FCR,mortality,intestinal lesion score,jejunal crypt depth,the levels of IFN-γand IL-17 in serum and IL-17/IL-10 in the jejunal mucosa,Clostridium perfringens concentrations in the cecum,and m RNA levels of IL-17/IL-10 in the ***,NE significantly increased the abundance of bacteria that are associated with inflammation,obesity and depression(Alistipes,Barnesiella,Intestinimonas,RF39 and UCG-005)and significantly decreased the abundance of short-chain fatty acid(SCFA)-producing bacteria(Anaerotruncus,Butyricicoccus and Bacteroides)in the *** significantly increased the abundance of SCFA-producing b

关键词： Broiler chicken Gut microbiota Immune function Macleaya cordata extract Necrotic enteritis

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 *** 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 *** 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 *** 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 *** effects of grain size,such as pinning and splitting,are amplified at higher brazing ***,micro-cracks initiate around brittle intermetallic compounds and propagate through the eutectic zone,leading to a cleavage fracture *** fracture stress of fine-grain specimens is higher than that of coarse-grain due to the complex micro-crack ***,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

A self-organization formation configuration based assignment probability and collision detection

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Journal of Systems Engineering and Electronics 2024年第1期35卷 222-232页

作者： song Wei WANG Tong YANG Guangxin ZHANG peng School of Harbin Engineering University Harbin 150001China Chinese Aeronautical Establishment Beijing 100010China

The formation control of multiple unmanned aerial vehicles(multi-UAVs)has always been a research *** on the straight line trajectory,a multi-UAVs target point assignment algorithm based on the assignment probability is proposed to achieve the shortest overall formation path of multi-UAVs with low complexity and reduce the energy *** order to avoid the collision between UAVs in the formation process,the concept of safety ball is introduced,and the collision detection based on continuous motion of two time slots and the lane occupation detection after motion is proposed to avoid collision between *** on the idea of game theory,a method of UAV motion form setting based on the maximization of interests is proposed,including the maximization of self-interest and the maximization of formation interest is proposed,so that multi-UAVs can complete the formation task quickly and reasonably with the linear trajectory assigned in ***,through simulation verification,the multi-UAVs target assignment algorithm based on the assignment probability proposed in this paper can effectively reduce the total path length,and the UAV motion selection method based on the maximization interests can effectively complete the task formation.

关键词： straight line trajectory assignment probability collision detection lane occupation detection maximization of interests

Effect of Air Distribution on the Transport Characteristics of Solid particles in the Thermal Storage and Release System of Circulating Fluidized Bed

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Journal of Thermal Science 2024年第4期33卷 1554-1563页

作者： JI Zengcai song Guoliang TANG Zihua SUN Liwei State Key Laboratory of Coal Conversion Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China Dalian National Laboratory for Clean Energy Dalian116023China

Solid particle heat storage technology offers a potential solution to the challenges posed by the significant growth of renewable energy sources,particularly in terms of grid security and ***,it has the capability to optimize the energy utilization efficiency of the power *** order to investigate the transport regulation characteristics of solid particles in the thermal storage and release system of a circulating fluidized bed(CFB),a test rig with a capacity of 0.1 MW(th)was *** rig was utilized to systematically study the transport regulation characteristics of solid particles under the double U-type valve feed structure and U-type valve discharge *** experimental findings indicate that the system's design enables efficient and rapid storage and release of solid particles in the *** air distribution mode,specifically the double U-type valve feed structure and the U-type valve discharge structure,significantly influence the feed and discharge characteristics of the ash storage *** was observed that the impact of loose air on these characteristics is more substantial than that of the return air,irrespective of the feed structure or the return *** adjusting the feed and discharge rate,it is recommended to adopt a scheme that involves coarse adjustment through loose air and fine adjustment through return air.

关键词： solid particle thermal storage air distribution mode transport regulation

Dynamic analysis and bifurcation control of a delayed fractional-order eco-epidemiological migratory bird model with fear effect

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International Journal of Biomathematics 2024年第3期17卷 1-33页

作者： Caihong song Ning Li College of Sciences Northeastern University 110819 ShenyangLiaoningP.R.China

In this paper,a new delayed fractional-order model including susceptible migratory birds,infected migratory birds and predators is proposed to discuss the spread of diseases among migratory *** of predators is considered in the model,as fear can reduce the reproduction rate and disease transmission rate among ***,some basic mathematical results of the proposed model are ***,time delay is regarded as a bifurcation parameter,and the delay-induced bifurcation conditions for such an uncontrolled system are established.A novel periodic pulse feedback controller is proposed to suppress the bifurcation *** is found that the control scheme can successfully suppress the bifurcation behavior of the system,and the pulse width can be arbitrarily selected on the premise of ensuring the control *** with the traditional time-delay feedback controller,the control scheme proposed in this paper has more advantages in practical application,which not only embodies the advantages of low control cost and easy operation but also caters to the periodic changes of the *** proposed control scheme,in particular,remains effective even after the system has been disrupted by a *** simulation verifies the correctness of the theoretical results.

关键词： Delayed fractional-order migratory birds fear Hopf bifurcation periodic pulse feedback

Experimental and Numerical Investigation on the Aerodynamic Characteristics of High-Speed pantographs with Supporting Beam Wind Deflectors

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Fluid Dynamics & Materials processing 2024年第1期20卷 127-145页

作者： Shiyang song Tongxin Han postgraduate Department China Academy of Railway SciencesBeijing100081China Locomotive&Car Research Institute China Academy of Railway Sciences Corporation LimitedBeijing100081China

Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)*** results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force *** also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”***,the lift force compensation provided by the wind deflectors increases with the size of the *** wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.

关键词： High-speed pantograph aerodynamic lift force supporting beam wind deflectors computational fluid dynamics(CFD)

Adaptive nonlinear Kalman filters based on credibility theory with noise correlation

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Chinese Journal of Aeronautics 2024年第6期37卷 232-243页

作者： Quanbo GE Zihao song Bingtao ZHU Bingjun ZHANG School of Automation Nanjing University of Information Science and TechnologyNanjing 210044China Jiangsu Collaborative Innovation Center on Atmospheric Environment and Equipment Technology Nanjing 210044China School of Electrical and Automation Engineering East China Jiaotong UniversityNanchang 330013China School of Logistics Engineering Shanghai Maritime UniversityShanghai 201306China School of Electronic and Information Engineering Tongji UniversityShanghai 200092China

To solve the divergence problem and overcome the difficulty in guaranteeing filtering accuracy during estimation of the process noise covariance or the measurement noise covariance with traditional new information-based nonlinear filtering methods,we design a new method for estimating noise statistical characteristics of nonlinear systems based on the credibility Kalman Filter(KF)theory considering noise *** method first extends credibility to the Unscented Kalman Filter(UKF)and Extended Kalman Filter(EKF)based on the credibility ***,an optimization model for nonlinear credibility under noise related conditions is established considering noise correlation.A combination of filtering smoothing and credibility iteration formula is used to improve the real-time performance of the nonlinear adaptive credibility KF algorithm,further expanding its application scenarios,and the derivation process of the formula theory is ***,the performance of the nonlinear credibility filtering algorithm is simulated and analyzed from multiple perspectives,and a comparative analysis conducted on specific experimental *** simulation and experimental results show that the proposed credibility EKF and credibility UKF algorithms can estimate the noise covariance more accurately and effectively with lower average estimation time than traditional methods,indicating that the proposed algorithm has stable estimation performance and good real-time performance.

关键词： Kalman filter Extended Kalman Filter(EKF) Unscented Kalman Filter(UKF) Credibility Noise correlation