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Superplasticity of fine-grained Mg-10Li alloy prepared by severe plastic deformation and understanding its deformation mechanisms

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Journal of Magnesium and Alloys 2024年第1期12卷 316-331页

作者： H.T.Jeong S.W.Lee W.J.Kim Department of Materials Science and Engineering Hongik UniversityMapo-guSangsu-dong 72-1Seoul 121-791Republic of Korea

The superplastic behavior and associated deformation mechanisms of a fine-grained Mg-10.1 Li-0.8Al-0.6Zn alloy(LAZ1011)with a grain size of 3.2μm,primarily composed of the BCCβphase and a small amount of the HCPαphase,were examined in a temperature range of 473 K to 623 *** microstructural refinement of this alloy was achieved by employing high-ratio differential speed *** best superplasticity was achieved at 523 K and at strain rates of 10^(-4)-5×10^(-4)s^(-1),where tensile elongations of 550±600%were *** the heating and holding stage of the tensile samples prior to tensile loading,a significant increase in grain size was observed at temperatures above 573 ***,it was important to consider this effect when analyzing and understanding the superplastic deformation behavior and *** the investigated strain rate range,the superplastic flow at low strain rates was governed by lattice diffusion-controlled grain boundary sliding,while at high strain rates,lattice diffusion-controlled dislocation climb creep was the rate-controlling deformation *** was concluded that solute drag creep is unlikely to *** the late stages of deformation at 523 K,it was observed that grain boundary sliding led to the agglomeration of theαphase,resulting in significant strain *** mechanism maps were constructed forβ-Mg-Li alloys in the form of 2D and 3D formats as a function of strain rate,stress,temperature,and grain size,using the constitutive equations for various deformation mechanisms derived based on the data of the current tests.

关键词： Magnesium-lithium alloy Superplasticity Severe plastic deformation Grain size Grain growth

Low-cycle fatigue behavior of solutionized and aged WE43 magnesium alloys at room temperature

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Journal of Magnesium and Alloys 2024年第6期12卷 2284-2297页

作者： Yong Cai Jianxiong Wei Hong Yan Yipeng Chen Rongshi Chen School of Materials Science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang 110016China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China

The low-cycle fatigue behavior of solutionized(T4)and aged(T6)WE43 magnesium alloys was studied at room *** total strain amplitudes(△ε_(t)/2)were 0.4%,0.5%,0.6%,0.7%and 1.0%.Detailed microstructure evolution was characterized by scanning electron microscope(SEM),electron backscattered diffraction(EBSD)and transmission electron microscopy(TEM).The results showed that plastic strain amplitude decreased with the increasing cycle number in T4 alloy,which is due to the dense persistent slip bands(PSBs)and dynamic precipitates hinderingdislocation *** contrast,the plastic strain amplitude increases gradually in T6 alloy,which is attributed to the enhanced activation of pyramidal *** low-cycle fatigue life of T6 alloy with larger fatigue ductility coefficient is longer than that of T4 *** Coffin-Manson model can accurately predict the fatigue life of T4 and T6 alloys compared to Jahed-Varvani(JV)energy *** T4 alloy,the fatigue damage mechanism was dominated by basal *** T6 alloy,the enhanced pyramidal slip plays an important role to accommodate plastic deformation.

关键词： Low-cycle fatigue WE43 alloy Cyclic hardening/softening JV model Dislocation

Experimental Study on Impingement Processes of Fuel Sprays on Biomimetic Structured Surfaces

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Journal of Bionic Engineering 2024年第1期21卷 362-373页

作者： Yanling Chen Liang Guo Wanchen Sun Yuying Yan Rong Xuan Junfeng Zhang State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130025China Faculty of Engineering University of NottinghamNottingham NG72RDUK

To improve the controllability of the wall-wetting process after the fuel spray-wall impingement in internal combustion engines,the methods of laser etching,chemical etching and surface free energy modification are used to prepare biomimetic structured surfaces with different *** impingement processes of diesel and n-butanol sprays on the walls under different conditions are experimentally *** the surface oleophilicity increases,the spreading radius of wall-impinging sprays *** about 5 s after the fuel injections,the fuel spray droplets hit the walls for the first time,and the secondary breakup and rebound *** mixture concentrations of different fuels hitting the various walls reach the peak *** a higher surface temperature,the peak value of the mixture concentration is mainly related to the heat flux to the fuel droplets in different boiling regimes from the metal *** concentration of the air–fuel mixture in the near wall region increases with increasing surface oleophilicity,increasing wall temperature and decreasing ambient *** with diesel,n-butanol presents a higher air–fuel mixture concentration in the near wall region.

关键词： Spray-wall impingement Morphological development Air-fuel mixture concentration Surface wettability Wall temperature:Ambient pressure

Flame Structure of Methane and Kerosene Combustion with a Compact Concave Flame-Holder using the LES-pdf Method

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Journal of Thermal Science 2024年第1期33卷 222-234页

作者： WANG Fang WANG Yunfan WEI Guanyi LIU Denghuan JIN Jie JONES P.William School of Energy and Power Engineering Beihang UniversityBeijingBeijing 100191China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Compact flame-holders for afterburners are an increasing requirement for modern aero ***,flame-holder design is non-trivial since high inlet temperatures,velocities,and elaborate structures induce complex turbulence,combustion,and spray coupling in modern *** this work,the LES-pdf and stochastic fields-Lagrangian particle spray methods are used to investigate methane and aviation kerosene combustion structures formed by new-type concave *** flow pattern,combustion mode,and flame structure of gaseous and liquid fuel around a concave flame-holder are analyzed,discussed,and compared with experimental *** reveal that the flame stability of a concave flame-holder is better than that of the non-concave ***,when using liquid fuel,the concave flame-holder forms a stable and compact *** results suggest concave flame-holders are a promising design for compact afterburners.

关键词： concave structure flame-holder LES-pdf spray combustion flame structure AECSC

Advances in Active Suspension Systems for Road Vehicles

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Engineering 2024年第2期33卷 160-177页

作者： Min Yu Simos AEvangelou Daniele Dini Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Department of Electrical and Electronic Engineering Imperial College LondonLondon SW72AZUK

Active suspension systems(ASSs)have been proposed and developed for a few decades,and have now once again become a thriving topic in both academia and industry,due to the high demand for driving comfort and safety and the compatibility of ASSs with vehicle electrification and *** review papers on ASSs mainly cover dynamics modeling and robust control;however,the gap between academic research outcomes and industrial application requirements has not yet been bridged,hindering most ASS research knowledge from being transferred to vehicle *** paper comprehensively reviews advances in ASSs for road vehicles,with a focus on hardware structures and control *** particular,state-of-the-art ASSs that have been recently adopted in production cars are discussed in detail,including the representative solutions of Mercedes active body control(ABC)and Audi predictive active suspension;novel concepts that could become alternative candidates are also introduced,including series active variable geometry suspension,and the active wheel-alignment *** with compact structure,small mass increment,low power consumption,high-frequency response,acceptable economic costs,and high reliability are more likely to be adopted by car *** terms of control strategies,the development of future ASSs aims not only to stabilize the chassis attitude and attenuate the chassis vibration,but also to enable ASSs to cooperate with other modules(e.g.,steering and braking)and sensors(e.g.,cameras)within a car,and even with high-level decision-making(e.g.,reference driving speed)in the overall transportation system-strategies that will be compatible with the rapidly developing electric and autonomous vehicles.

关键词： Active suspension Vehicle dynamics Robust control Ride comfort Chassis attitude

Communication Resources Allocation for Time Delay Reduction of Frequency Regulation Service in High Renewable Penetrated Power System

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 468-480页

作者： Hongjie He Ning Zhang Chongqing Kang Song Ci Fei Teng Goran Strbac State Key Laboratory of Power Systems Department of Electrical EngineeringTsinghua UniversityBeijing 100084China Department of Electrical and Electronic Engineering Imperial College LondonSW72BULondonU.K

The high renewable penetrated power system has severe frequency regulation *** resources can provide frequency regulation services but are limited by com-munication time *** paper proposes a communication resources allocation model to reduce communication time delay in frequency regulation *** device resources and wireless spectrum resources are allocated to distributed resources when they participate in frequency *** reveal impact of communication resources allocation on time delay reduction and frequency regulation ***,we study communication resources allocation solution in high renewable energy penetrated power *** provide a case study based on the HRP-38 *** show communication time delay decreases distributed resources'ability to provide frequency regulation *** the other hand,allocating more communication resources to distributed resources'communica-tion services improves their frequency regulation *** power systems with renewable energy penetration above 70%,required communications resources are about five times as many as 30%renewable energy penetrated power systems to keep frequency performance the *** Terms-Communication resources allocation,commun-ication time delay,distributed resource,frequency regulation,high renewable energy penetrated power system.

关键词： Communication resources allocation communication time delay distributed resource frequency regulation high renewable energy penetrated power system

Interactive mechanism and friction modelling of transient tribological phenomena in metal forming processes: A review

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Friction 2024年第3期12卷 375-395页

作者： Xiao YANG Heli LIU Lemeng ZHANG Yiran HU Denis J.POLITIS Mohammad M.GHARBI Liliang WANG Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Department of Mechanical and Manufacturing Engineering University of CyprusNicosia 1678Cyprus Quaker Houghton Deutschland GmbH Dortmund 44319Germany

The accurate representation of tribological boundary conditions at the tool–workpiece interface is crucial for analysis and optimization of formability,material flow,and surface quality of components during metal forming *** has been found that these tribological conditions vary spatially and historically with process parameters and contact *** time-dependent tribological behaviours are also known as transient tribological phenomena,which are widely observed during forming processes and many other manufacturing application ***,constant friction values are usually assigned to represent complex and dynamic interfacial conditions,which would introduce deviations in the relevant *** this paper,transient tribological phenomena and the contemporary understanding of the interaction between friction and wear are reviewed,and it has been found that these phenomena are induced by the transitions of friction mechanisms and highly dependent on complex loading conditions at the *** modelling techniques for transient behaviours for metal forming applications are also *** accurately describe the evolutionary friction values and corresponding wear during forming,the advanced interactive friction modelling has been established for different application scenarios,including lubricated condition,dry sliding condition(metal-on-metal contact),and coated system.

关键词： transient tribological phenomena interactive friction mechanism modelling techniques metal forming

Application of deep learning for informatics aided design of electrode materials in metal-ion batteries

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Green Energy & Environment 2024年第5期9卷 877-889页

作者： Bin Ma Lisheng Zhang Wentao Wang Hanqing Yu Xianbin Yang Siyan Chen Huizhi Wang Xinhua Liu School of Transportation Science and Engineering Beihang UniversityBeijing102206China College of Automotive Engineering Jilin UniversityChangchun130022China Department of Mechanical Engineering Imperial College LondonLondonSW72BXUK

To develop emerging electrode materials and improve the performances of batteries,the machine learning techniques can provide insights to discover,design and develop battery new materials in high-throughput *** this paper,two deep learning models are developed and trained with two feature groups extracted from the Materials Project datasets to predict the battery electrochemical performances including average voltage,speciﬁc capacity and speciﬁc *** deep learning models are trained with the multilayer perceptron as the *** Bayesian optimization and Monte Carlo methods are applied to improve the prediction accuracy of *** on 10 types of ion batteries,the correlation coefﬁcients are maintained above 0.9 compared to DFT calculation results and the mean absolute error of the prediction results for voltages of two models can reach 0.41 V and 0.20 V,*** electrochemical performance prediction times for the two trained models on thousands of batteries are only 72.9 ms and 75.7 ***,the two deep learning models are applied to approach the screening of emerging electrode materials for sodium-ion and potassium-ion *** work can contribute to a high-throughput computational method to accelerate the rational and fast materials discovery and design.

关键词： Cathode materials Material design Electrochemical performance prediction Deep learning Metal-ion batteries

Preoperative serum cortisone levels are associated with cognition in preschool‑aged children with tetralogy of Fallot after corrective surgery:new evidence from human populations and mice

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World Journal of Pediatrics 2024年第2期20卷 173-184页

作者： Si-Yu Ma Yu-Ting Liu Yue-Shuang Cun Qiang Wang Ming-Cui Fu Ke-De Wu Xin-Yu Cai Shu-Ting Cheng Nishant Patel Min Da Liang Hu Zhuoga Deqin Xue-Jun Kang Ming Yang Xu-Ming Mo Department of Cardiothoracic Surgery Children’s Hospital of Nanjing Medical University72 Guangzhou RoadNanjing 210008China Department of Radiology Children’s Hospital of Nanjing Medical University72 Guangzhou RoadNanjing 210008China Key Laboratory of Child Development and Learning Science Research Center For Learning ScienceSchool of Biological Sciences&Medical EngineeringMinistry of EducationSoutheast UniversityNanjing 210096China Medical School of Nanjing University Nanjing 210093China

Background Tetralogy of Fallot(TOF)is the most common cyanotic congenital heart *** with TOF would be confronted with neurological impairment across their *** study aimed to identify the risk factors for cerebral morphology changes and cognition in postoperative preschool-aged children with *** We used mass spectrometry(MS)technology to assess the levels of serum metabolites,Wechsler preschool and primary scale of intelligence-Fourth edition(WPPSI-Ⅳ)index scores to evaluate neurodevelopmental levels and multimodal magnetic resonance imaging(MRI)to detect cortical morphological *** Multiple linear regression showed that preoperative levels of serum cortisone were positively correlated with the gyrification index of the left inferior parietal gyrus in children with TOF and negatively related to their lower visual spaces index and nonverbal ***,preoperative SpO_(2) was negatively correlated with levels of serum cortisone after adjusting for all ***,after intervening levels of cortisone in chronic hypoxic model mice,total brain volumes were reduced at both postnatal(P)11.5 and P30 *** Our results suggest that preoperative serum cortisone levels could be used as a biomarker of neurodevelopmental impairment in children with *** study findings emphasized that preoperative levels of cortisone could influence cerebral development and cognition abilities in children with TOF.

关键词： Cognition Cortisone MRI Neurodevelopment Tetralogy of Fallot