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Precipitating thermally reinforcement phase in aluminum alloys for enhanced strength at 400℃

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Journal of Materials Science & Technology 2024年第5期172卷 71-82页

作者： Xiang Su Yuan Lei Yang Chen Hongjie Qu Zhixiang Qi Gong Zheng Xu liu Henggao Xiang guang Chen National Key Laboratory of Advanced Casting Technologies MIIT Key Laboratory of Advanced Metallic and Intermetallic Materials TechnologyEngineering Research Center of Materials Behavior and DesignMinistry of EducationNanjing University of Science and TechnologyNanjing 210094China School of Aviation and Mechanical Engineering Changzhou Institute of TechnologyChangzhou 213032China

Heat-resistant aluminum alloys are widely used in aerospace and automotive fields for manufacturing hot components due to their advantages in lightweight design and energy ***,the high-temperature strength of existing cast aluminum alloys is always limited to about 100 MPa at 350℃due to coarsening and transformation of strengthening ***,we reveal that the yield strength and ultimate tensile strength of the T6 state Al-8.4Cu-2.3Ce-1.0Mn-0.5Ni-0.2Zr alloy at 400◦C increase by 34%and 44%after re-aging at 300℃for 100 h,and its thermal strength exhibits distinguished ad-vantage over traditional heat-resistant aluminum *** enhanced elevated-temperature strength is attributed to the reprecipitation of the Ni-bearing T-Al_(20)Cu_(2)Mn_(3)phase,whose number density increases over one *** significant segregation of Ni,Ce,and Zr elements at the interfaces helps improve the thermal stability of the T *** thermostable T phase effectively strengthens the matrix by in-hibiting dislocation ***,a highly interconnected 3D intermetallic network along the grain boundaries can still remain after long-term re-aging at 300℃,which is conducive to imposing a drag on the grain boundaries at high *** finding offers a viable route for enhancing the elevated-temperature strength of heat-resistant aluminum alloys,which could provide expanded opportunities for higher-temperature applications.

关键词： Aluminum alloys Precipitation Thermally reinforcement phase Re-aging treatment High-temperature strength

Chiral phonon activated spin Seebeck effect in chiral materials

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Science China(Physics,Mechanics & Astronomy) 2024年第3期67卷 149-155页

作者： Xiao Li Jinxin Zhong Jinluo Cheng Hao Chen Huiqian Wang jun liu Dali Sun Lifa Zhang jun Zhou Phonon Engineering Research Center of Jiangsu Province Center for Quantum Transport and Thermal Energy ScienceSchool of Physics and TechnologyNanjing Normal UniversityNanjing 210023China Center for Phononics and Thermal Energy Science China-EU Joint Lab for NanophononicsSchool of Physics Science and EngineeringTongji UniversityShanghai 200092China Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of ScienceChangchun 130033China Department of Mechanical and Aerospace Engineering North Carolina State UniversityRaleigh NC 27606USA Department of Physics North Carolina State UniversityRaleigh NC 27695USA Organic and Carbon Electronics Laboratories(ORaCEL) North Carolina State UniversityRaleigh NC 27606USA

Efficient generation of spin polarization is very important for spintronics and quantum computation. In chiral materials without magnetic order nor spin-orbit coupling, we find a new spin selectivity effect—chiral phonon activated spin Seebeck(CPASS)effect. Starting with the nonequilibrium distribution of chiral phonons under a temperature gradient, the CPASS coefficients are computed based on the Boltzmann transport theory. With both the phonon-drag and band transport contributions, the spin accumulations generated by the CPASS effect exhibit quadratic dependence on the temperature gradient. The strength of the CPASS effect and the relative magnitude of both contributions are tunable by the chemical potential modulation. The CPASS effect, which gives a promising explanation on the traditional chiral-induced spin selectivity effect, provides opportunities for the exploration of advanced spintronic devices based on chiral materials even in the absence of any magnetic order and spin-orbit coupling.

关键词： spin Seebeck effect chiral phonon phonon-drag contribution efficient spin generation

Surface reconstruction of heterostructures in alkaline medium towards enhanced electrocatalytic hydrogen evolution

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Rare Metals 2024年第6期43卷 2636-2647页

作者： Ming-Yang Yang Ji Yuan Xue-Lian Fu Jing-Jing Chen Jing Hu Zhou-guang Lu Chen liu guangdong Research Center for Interfacial Engineering of Functional Materials Shenzhen Key Laboratory of Polymer Science and TechnologyShenzhen Key Laboratory of Energy Electrocatalytic MaterialsCollege of Materials Science and EngineeringShenzhen UniversityShenzhen 518060China Shenzhen Key Laboratory of Interfacial Science and Engineering of Materials Department of Materials Science and EngineeringSouthern University of Science and TechnologyShenzhen 518055China

Constructing heterostructures has proved to be a successful strategy to fabricate electrocatalysts with high efficiency for water ***,the structure evolution in alkaline hydrogen evolution reaction lacks investigation and the specific active center remains ***,we take the well-designed Ni_(3)S_(2)@VO_(2) heterostructures as a model to investigate the electrocatalytic activity and the surface reconstruction process of heterostructure catalysts in alkaline *** Ni_(3)S_(2)@VO_(2) heterostructures,with Ni_(3)S_(2) nanorods as the core and VO_(2) nanoflakes as the shell,coupled with the high conductive Ni_(3)S_(2),the hydrophilic VO_(2) and modulated electronic structures at the interfaces,exhibited prominent activity and superior stability at various current ***,the ex-situ characterizations confirmed that the surface reconstruction from Ni_(3)S_(2)@VO_(2) into Ni_(3)S_(2)@amorphous-Ni(OH)_(2) in alkaline media could optimize the water dissociation barrier and exposed large active area,thereby contributing to improved electrocatalytic *** study not only introduces novel high-performance electrocatalysts for hydrogen evolution reaction(HER),but also provides a new avenue for re-examining hetero-structural catalysts in alkaline solutions.

关键词： Heterostructures Ni_(3)S_(2)@VO_(2) Surface reconstruction Water dissociation Alkaline hydrogen evolution

Optimization of the co-closing law of guide vanes and blades for bulb turbines based on CFD

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Journal of Hydrodynamics 2024年第2期36卷 363-377页

作者： Hui liu Yun-fa Lin Yong-guang Cheng Song Xue Mao-jia Tang Jian Zhang Jia-yi Fan State Key Laboratory of Water Resources Engineering and Management Wuhan UniversityWuhan430072China Dongfang Electric Machinery Co. Ltd.Deyang618000China

The load rejection transient process of bulb turbine units is critical to safety of hydropower stations,and determining appropriate closing laws of guide vanes(GVs)and runner blades(RBs)for this process is of *** this study,we proposed a procedure to optimize the co-closing law of GVs and RBs by using computational fluid dynamics(CFD),combined with the design of experiment(DOE)method,approximation model,and genetic optimization *** sensitivity of closing law parameters on the histories of head,speed,and thrust was analyzed,and a two-stage GVs’closing law associating with a linear RBs’closing law was *** results show that GVs dominate the transient characteristics by controlling the change of *** GVs’first-stage closing speed while shortening first-stage closing time can not only significantly reduce the maximum rotational speed but also suppress the water hammer pressure;slowing GVs’second-stage closing speed is conducive to controlling the maximum reverse axial *** directly affect the runner *** RBs’closing speed can further reduce the rotational speed and the maximum reverse axial *** safety margin of each control parameter,flow patterns,and pressure pulsations of a practical hydropower station were all improved after optimization,demonstrating the effectiveness of this method.

关键词： Bulb turbine load rejection transient process double regulation closing law optimization computational fluid dynamics(CFD)

980 nm Near-Infrared Light-Emitting Diode Using All-Inorganic Perovskite Nanocrystals Doped with Ytterbium Ions

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Tsinghua Science and Technology 2024年第1期29卷 207-215页

作者： Zhenglan Ye Taoran liu Dan Chen Yazhou Yang Jiayi Li Yaqing Pang Xiangquan liu Yuhua Zuo jun Zheng Zhi liu Buwen Cheng State Key Laboratory on Integrated Optoelectronics Institute of SemiconductorsChinese Academy of SciencesBeijing 100083China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China Intelligent Network Research Institute Zhejiang LabHangzhou 311100China

All-inorganic perovskite(CsPbX3)nanocrystals(NCs)have recently been widely investigated as versatile solution-processable light-emitting *** to its wide-bandgap nature,the all-inorganic perovskite NC Light-Emitting Diode(LED)is limited to the visible region(400-700 nm).A particularly difficult challenge lies in the practical application of perovskite NCs in the infrared-spectrum *** this work,a 980 nm NIR all-inorganic perovskite NC LED is demonstrated,which is based on an efficient energy transfer from wide-bandgap materials(CsPbCl3 NCs)to ytterbium ions(Yb3+)as an NIR emitter doped in perovskite *** optimized CsPbCl3 NC with 15 mol%Yb3+doping concentration has the strongest 980 nm photoluminescence(PL)peak,with a PL quantum yield of 63%.An inverted perovskite NC LED is fabricated with the structure of ITO/PEDOT:PSS/poly-TPD/CsPbCl3:15 mol%Yb3+NCs/TPBi/LiF/*** LED has an External Quantum Efficiency(EQE)of 0.2%,a Full Width at Half Maximum(FWHM)of 47 nm,and a maximum luminescence of 182 cd/m?.The introduction of Yb3+doping in perovskite NCs makes it possible to expand its working wavelength to near-infrared band for next-generation light sources and shows potential applications for optoelectronic integration.

关键词： perovskite nanocrystals rare-earth doping Light-Emitting Diode(LED) near-infrared optical interconnection

Extracting multi-objective multigraph features for the shortest path cost prediction:Statistics-based or learning-based?

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Green Energy and Intelligent Transportation 2024年第1期3卷 1-15页

作者： Songwei liu Xinwei Wang Michal Weiszer jun Chen School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon E14NSUnited Kingdom

Efficient airport airside ground movement(AAGM)is key to successful operations of urban air *** studies have introduced the use of multi-objective multigraphs(MOMGs)as the conceptual prototype to formulate *** calculation of the shortest path costs is crucial for the algorithmic heuristic search on MOMGs,however,previous work chiefly focused on single-objective simple graphs(SOSGs),treated cost enquires as search problems,and failed to keep a low level of computational time and storage *** paper concentrates on the conceptual prototype MOMG,and investigates its node feature extraction,which lays the foundation for efficient prediction of shortest path *** extraction methods are implemented and compared:a statistics-based method that summarises 22 node physical patterns from graph theory principles,and a learning-based method that employs node embedding technique to encode graph structures into a discriminative vector *** former method can effectively evaluate the node physical patterns and reveals their individual importance for distance prediction,while the latter provides novel practices on processing multigraphs for node embedding algorithms that can merely handle *** regression models are applied to predict the shortest path costs to demonstrate the performance of *** experiments on randomly generated benchmark MOMGs show that(i)the statistics-based method underperforms on characterising small distance values due to severe overestimation;(ii)A subset of essential physical patterns can achieve comparable or slightly better prediction accuracy than that based on a complete set of patterns;and(iii)the learning-based method consistently outperforms the statistics-based method,while maintaining a competitive level of computational complexity.

关键词： Multi-objective multigraph Feature extraction Shortest path cost prediction Node patterns Node embeddings Regression

Resilient Smart Power Grid Synchronization Estimation Method for System Resilience with Partial Missing Measurements

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1307-1319页

作者： Yi Wang Yanxin liu Mingdong Wang Venkata Dinavahi jun Liang Yonghui Sun School of Electrical and Information Engineering Zhengzhou UniversityZhengzhou 450001China Henan Engineering Research Center of Power Electronics and Energy Systems Zhengzhou 450001China Department of Electrical and Computer Engineering University of AlbertaEdmontonAB T6G 2V4Canada School of Engineering Cardiff UniversityCardiff CF243AAUK College of Energy and Electrical Engineering Hohai UniversityNanjing 210098China IEEE

With the increasing demand for power system stability and resilience,effective real-time tracking plays a crucial role in smart grid ***,most studies have focused on measurement noise,while they seldom think about the problem of measurement data loss in smart power grid *** solve this problem,a resilient fault-tolerant extended Kalman filter(RFTEKF)is proposed to track voltage amplitude,voltage phase angle and frequency ***,a threephase unbalanced network’s positive sequence fast estimation model is ***,the loss phenomenon of measurements occurs randomly,and the randomness of data loss’s randomness is defined by discrete interval distribution[0,1].Subsequently,a resilient fault-tolerant extended Kalman filter based on the real-time estimation framework is designed using the timestamp technique to acquire partial data loss ***,extensive simulation results manifest the proposed RFTEKF can synchronize the smart grid more effectively than the traditional extended Kalman filter(EKF).

关键词： Dynamic state estimation Kalman filter partial missing measurements power systems smart grid synchronized measurements

Emerging high-entropy strategy: A booster to the development of cathode materials for power batteries

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Journal of Advanced Ceramics 2024年第8期13卷 1093-1118页

作者： Liping Huang Jinging Zhu J-Xuan liu Houzheng Wu Guo-jun Zhang State Key Laboratory for Modification of Chemical Fibers and Polymer Materials Institute of Functional MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai 201620China SIAMC Advanced Materials Cooperation Huzhou 313100China

The coordinated development of new energy vehicles and the energy storage industry has become essential for reducing carbon *** cathode material is the key material that determines the energy density and cost of a power battery,but currently developed and applied cathode materials cannot meet the requirements for high specific capacity,low cost,safety,and good ***-entropy materials(HEMs)are a new type of single-phase material composed of multiple principal elements in equimolar or near-equimolar *** interaction between multiple elements can play an important role in improving the comprehensive properties of the material,which is expected to solve the limitations of battery materials in practical ***,this review provides a comprehensive overview of the current development status and modification strategies of power batteries(lithium-ion batteries(LiBs)and sodium-ion batteries(SIBs)),proposes a high-entropy design strategy,and analyses the structure-activity relationship between the high-entropy effects and battery ***,future research topics related to high-entropy cathode materials,including computational guide design,specific synthesis methods,high-entropy electrochemistry,and high-throughput databases,are *** review aims to provide practical guidance for the development of high-entropy cathode materials for next-generation power batteries.

关键词： cathode materials lithium-ion battery(LIB) sodium-ion battery(SIB) high-entropy strategy

Influence characteristics of water penetration on fibre-reinforced polymer/rigid polyurethane foam interface of the composite cross-arm considering natural ageing

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High Voltage 2024年第1期9卷 81-93页

作者： jun Xie Zhe Zhou Ziqian liu Haonan Tian Sigang Zhang Qing Xie Hebei Provincial Key Laboratory of Power Transmission Equipment Security Defense North China Electric Power UniversityBaodingChina State Grid Gansu Electric Power Company LanzhouChina

Fibre-reinforced polymer(FRP)/rigid polyurethane foam(RPUF)interface is susceptible to moisture intrusion in addition to natural ageing during *** study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics(MD)*** absorption,shear strength,and leakage current tests were used to clarify the changes in the interface *** degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and *** results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the *** addition,water mainly invades the interface through *** water penetration,the interfacial bonding strength and insulation performance significantly *** and hydrolysis of interfacial materials are the main reasons for decreased interfacial *** can cause irreversible damage to the interface,increasing interface defects and water *** vicious cycle of material hydrolysis is the ultimate cause of interfacial *** polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.

关键词： interface polyurethane interfacial