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Journal of Materials Science & Technology 2013年第12期29卷 1116-1122页

作者： z.a.luo G.M.Xie z.Y.Ma G.L.Wang G.D.Wang State Key Laboratory of Rolling and Automation Northeastern University Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences

As-extruded zK60 and zK60-Y magnesium alloy plates were successfully processed via friction stir processing （FSP） at a tool rotation rate of 1600 r/rain and a traverse speed of 200 mm/min. FSP resulted in the formation of equiaxed recrystallized microstructures with the average grain sizes of ,-8.5 and -4.7 μm in the zK60 and zK60-Y alloys, respectively. Moreover, FSP broke and dispersed the Mgzn2 and W-phase （Mg3zn3Y2） particles and dissolved Mgzn2 phase in the FSP zK60 alloy. With the addition of rare earth element yttrium （Y） into the zK60 alloy, the ratio of the high angle grain boundaries （HAGBs） in the FSP alloys increased from 64% to 90%, and a certain amount of twins appeared in the FSP zK60-Y alloy. The maximum elongation of 1200% and optimum strain rate of 3 X 10-3 s-1 achieved at 450 °C in the FSP zK60-Y alloy were substantially higher than those of the FSP zK60 alloy. This is attributed to the fine grains with high ratio of HAGBs and the distribution of a large number of dispersed second phase particles with high thermal stability in the FSP zK60-Y alloy. Grain boundary sliding was identified as the primary deformation mechanism in the FSP zK60 and zK60-Y alloys from the superplastic data analyses and surficial morphology observations.

关键词： Magnesium alloy Friction stir processing Rare earth element Microstructure Superplasticity

Microstructure and Mechanical Properties of X80 Pipeline Steel Joints by Friction Stir Welding Under Various Cooling Conditions

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Acta Metallurgica Sinica(English Letters) 2020年第1期33卷 88-102页

作者： G.M.Xie R.H.Duan P.Xue z.Y.Ma H.L.Liu z.a.luo State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110819China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

X80 pipeline steel plates were friction stir welded(FSW)under air,water,liquid CO2+water,and liquid CO2 cooling conditions,producing defect-free *** microstructural evolution and mechanical properties of these FSW joints were *** granular bainite was observed in the nugget zone(Nz)under air cooling,and lath bainite and lath martensite increased signifi cantly as the cooling medium temperature *** particular,under the liquid CO2 cooling condition,a dual phase structure of lath martensite and fi ne ferrite appeared in the *** to the case under air cooling,a strong shear texture was identifi ed in the Nzs under other rapid cooling conditions,because the partial deformation at elevated temperature was retained through higher cooling *** liquid CO2 cooling,the highest transverse tensile strength and elongation of the joint reached 92%and 82%of those of the basal metal(BM),respectively,due to the weak tempering softening.A maximum impact energy of up to 93%of that of the BM was obtained in the Nz under liquid CO2 cooling,which was attributed to the operation of the dual phase of lath martensite and fi ne ferrite.

关键词： Friction stir welding Pipeline steel Microstructure Mechanical properties Cooling

Effect of Rotation Rate on Microstructure and Mechanical Properties of Friction Stir Spot Welded DP780 Steel

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Journal of Materials Science & Technology 2016年第4期32卷 326-332页

作者： G.M.Xie H.B.Cui z.a.luo W.Yu J.Ma G.D.Wang State Key Laboratory of Rolling and Automation Northeastern University

DP780 steel sheets consisting of ferrite and martensite were successfully friction stir spot welded （FSSW） at the rotation rates of 500 to 1500 r/min using a W-Re alloy tool, The effect of rotation rate on micro- structure and mechanical properties of the FSSW DP780 was investigated. The peak temperatures in the welds at various rotation rates were identified to be above A3 temperature. FSSW caused the dynamic recrystallization in the stir zone （Sz）, thereby producing the fine equiaxed grain structures. At the higher rotation rates of≥1000 r/min, a full martensitic structure was observed throughout the Szs, whereas at the lower rotation rate of 500 r/min, the Sz consisted of a fine dual phase structure of ferrite and mar- tensite due to the action of deformation induced ferrite transformation. The maximum average failure load as high as 18.2 kN was obtained at the rotation rate of 1000 r/min and the fracture occurred at the thinned upper sheet.

关键词： Friction stir spot weldingDual phase steelMicrostructureDeformation induced ferritetransformationMechanical property

Microstructural refinement mechanism and its effect on toughness in the nugget zone of high-strength pipeline steel by friction stir welding

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Journal of Materials Science & Technology 2021年第34期93卷 221-231页

作者： R.H.Duan G.M.Xie P.Xue z.Y.Ma z.a.luo C.Wang R.D.K.Misra State Key Laboratory of Rolling and Automation Northeastern UniversityNo.3 Wenhua RoadShenyang 110819China Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Metallurgy Northeastern UniversityNo.3 Wenhua RoadShenyang 110819China Department of Metallurgical Materialsand Biomedical EngineeringUniversity of Texas at El PasoTX 79968USA

High-strength pipeline steel was subjected to friction stir welding(FSW)at rotation rates of 400-700 rpm,and the grain refinement mechanism of the nugget zone(Nz)was *** thermomechanical process during FSW in the Nz was simulated by multi-pass thermal compression,thereby achieving the austenitic non-recrystallization temperature(T_(nr)).The austenitic non-recrystallization in the Nz at the lowest rotation rate of 400 rpm caused a significant grain ***,the reduced rotation rate also resulted in the formation of a high ratio of island-like martensite-austenite(M-A)*** toughness of the Nzs was enhanced as the rotation rate decreased,which is attributed to the fine effective grains and homogeneously distributed fine M-A constituents dramatically inhibiting crack initiation and propagation.

关键词： Pipeline steel Friction stir welding Grain refinement M-A constituent Toughness

Asymmetrical Fault Current Calculation Method and Influencing Factors Analysis of Droop-Controlled Inverters

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CSEE Journal of Power and Energy Systems 2024年第2期10卷 562-573页

作者： Huimin zhao zhikang Shuai Jun Ge An luo Weimin Wu z.John Shen College of Electrical and Information Engineering Hunan UniversityChangsha 410006China Electrical Engineering Department Shanghai Maritime UniversityShanghai 201306China Department of Electrical and Computer Engineering Ilinois Institute of TechnologyChicagoIL 60616 USA

Since the fault dynamic of droop-controlled inverter is different from synchronous generators (SGs), protection devices may become invalid, and the fault overcurrent may damage power electronic devices and threaten the safety of the microgrid. Therefore, it is imperative to conduct a comprehensive fault analysis of the inverter to guide the design of protection schemes. However, due to the complexity of droop control strategy, existing literatures have simplified asymmetric fault analysis of droop-controlled inverters to varying degrees. Therefore, accurate fault analysis of a droop-controlled inverter is needed. In this paper, by analyzing the control system, an accurate fault model is established. Based on this, a calculation method for instantaneous asymmetrical fault current is proposed. In addition, the current components and current characteristics are analyzed. It was determined that fault currents are affected by control loops, fault types, fault distance and nonlinear limiters. In particular, the influences of limiters on the fault model, fault current calculation and fault current characteristics were analyzed. Through detailed analysis, it was found that dynamics of the control loop cannot be ignored, the fault type and fault distance determine fault current level, and part of the limiters will totally change the fault current trend. Finally, calculation and experimental results verify the correctness of the proposed method.

关键词： Asymmetrical fault analysis droop control fault current calculation method limiter transient fault characteristics

Switching Behavior of Cascode GaN Under Influence of Gate Driver

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CSEE Journal of Power and Energy Systems 2024年第4期10卷 1816-1833页

作者： Bin luo Guangzhao luo Sihai Li School of Automation Northwestern Polytechnical UniversityXi’an 710072China

With high-frequency,low power dissipation and high-efficiency characteristics,Gallium nitride(GaN)power devices are of significant benefit in designing high-speed motor drives,as they improve performance and reduce ***,due to the cascode structure,coupling with the parasitics in gate driver and power circuits,power converters based on cascode GaN are prone to overshoot and oscillate on switching waveforms,which may lead to serious EMC problems,or even device *** complicated structure of cascode GaN device makes the gate driver design comparatively *** analytical model of the switching process considering gate driver parameters is proposed in this *** influence of gate driver parameters on switching behavior is investigated from the perspective of switching speed,waveform overshoot,and power ***-offs among overshoot,switching speed,and power loss are discussed;guidelines to design gate driver parameters are given.

关键词： Gallium nitride(GaN) gate driver oscillation and overshoot switching characteristics

Large language model and domain-specific model collaboration for smart education

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Frontiers of Information Technology & Electronic Engineering 2024年第3期25卷 333-341页

作者： Yawei luo Yi YANG School of Software Technology Zhejiang UniversityNingbo 315048China College of Computer Science and Technology Zhejiang UniversityHangzhou 310027China

In this paper,we introduce the large language model and domain-specific model collaboration(LDMC)framework designed to enhance smart *** LDMC framework leverages the comprehensive and versatile knowledge of large domain-general models,combines it with the specialized and disciplinary knowledge from small domainspecific models(DSMs),and incorporates pedagogy knowledge from learning theory *** integration yields multiple knowledge representations,fostering personalized and adaptive educational *** explore various applications of the LDMC framework in the context of smart education.

关键词： smart language knowledge

In Situ Polymer Gel Electrolyte in Boosting Scalable Fibre Lithium Battery Applications

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Nano-Micro Letters 2024年第11期16卷 170-173页

作者： Jie luo Qichong zhang Key Laboratory of Multifunctional Nanomaterials and Smart Systems Chinese Academy of SciencesSuzhou Institute of Nano-Tech and Nano-Bionics398 Ruoshui RoadSuzhou 215123People’s Republic of China

The poor interfacial stability not only deteriorates fibre lithium-ion batteries(FLBs)performance but also impacts their scalable *** efficiently address these challenges,*** Peng team proposed a generalized channel structures strategy with optimized in situ polymerization technology in their recent *** resultant FLBs can be woven into different-sized powering textiles,providing a high energy density output of 128 Wh kg^(-1) and simultaneously demonstrating good durability even under harsh *** a promising strategy expands the horizon in developing FLB with particular polymer gel electrolytes,and significantly ever-deepening understanding of the scaled wearable energy textile system toward a sustainable future.

关键词： High-performance fibre lithium batteries Gel electrolytes Channel structures Stable interface Scalable application

Catalyst design and structure control for photocatalytic refineries of cellulosic biomass to fuels and chemicals

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Journal of Energy Chemistry 2024年第7期94卷 102-127页

作者： Lulu Sun Nengchao luo State Key Laboratory of Catalysis Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Lignocellulosic biomass is the largest renewable hydrocarbon resource on *** cellulose,one of the major components of lignocellulose,powered by solar energy is a promising way of providing lowcarbon-footprint energy chemicals such as H_(2),HCOOH,CO,and transportation ***-of-the-art biorefineries target the full use of biomass feedstocks as they have a maximum collection radius of 75-100 km,requesting efficient and selective photocatalysts that significantly influence the outcome of photocatalytic ***-performed photocatalysts can harvest a broad solar spectrum and are active in breaking the chemical bonds of cellulose,decreasing the capital investments of ***,photocatalysts should control the selectivity of cellulose conversion,originating target products to level down separation *** separation in photocatalysts and interfacial charge transfer between photocatalysts and cellulose affect the activity and selectivity of cellulose refineries to H2 and carbonaceous *** account for the challenges above,this review summarizes photocatalysts for the refineries of cellulose and downstream platform molecules based on the types of products,with the structure features of different types of photocatalysts discussed in relation to the targets of either improving the activity or product *** addition,this review also sheds light on the methods for designing and regulating photocatalyst structures to facilitate photocatalytic refineries of cellulose and platform molecules,meanwhile summarizing proposed future research challenges and opportunities for designing efficient photocatalysts.

关键词： Photocatalysts Biorefineries Cellulose Fuels Hydrogen

Precision regulation of plant aromatic amino acid homeostasis

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Science China(Life Sciences) 2024年第6期67卷 1316-1317页

作者： Jie luo Yazhouwan National Laboratory(YNL) Sanya 572025China School of Breeding and Multiplication(Sanya Institute of Breeding and Multiplication) Hainan UniversitySanya 572025China

The aromatic amino acids(AAAs)phenylalanine(Phe),tyrosine(Tyr),and tryptophan(Trp)are not only building blocks of proteins,but also precursors of numerous primary and specialized metabolites(Schenck and Maeda,2018).For instance,Trp is a precursor of the phytohormone auxin and the plant defense compounds indole glucosinolates,while Phe serves as a precursor of lignin,coumarin and *** plant natural products such as morphine and vitamin E are derived from Tyr,and have been employed in human medicine and nutrition(Schenck and Maeda,2018;Wu et al.,2022;Yokoyama et al.,2021).

关键词： aromatic instance coumarin

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