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Dissipationless layertronics in axion insulator MnBi2Te4

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national Science review 2024年第6期11卷 189-196页

作者： Shuai Li Ming Gong Shuguang cheng hua Jiang x.c.xie School of Physical Science and Technology Soochow University Institute for Advanced Study Soochow University International center for Quantum Materials School of Physics Peking University Department of Physics Northwest University Interdisciplinary center for Theoretical Physics and Information Sciences Fudan University hefei national Laboratory

Surface electrons in axion insulators are endowed with a topological layer degree of freedom followed by exotic transport phenomena, e.g., the layer hall effect. here, we propose that such a layer degree of freedom can be manipulated in a dissipationless way based on the antiferromagnetic MnBi2Te4with tailored domain structure. This makes MnBi2Te4a versatile platform to exploit the ‘layertronics’ to encode, process and store information. Importantly, the layer filter, layer valve and layer reverser devices can be achieved using the layer-locked chiral domain wall modes. The dissipationless nature of the domain wall modes makes the performance of the layertronic devices superior to those in spintronics and valleytronics. Specifically, the layer reverser, a layer version of the Datta–Das transistor, also fills up the blank in designing the valley reverser in valleytronics. Our work sheds light on constructing new generation electronic devices with high performance and low-energy consumption in the framework of layertronics.

关键词： axion insulator MnBi2Te4 layertronics antiferromagnetic domain wall dissipationless transport

cognition on oxidation behavior of ni-based superalloy Gh4742 when exposed to water vapor

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Journal of Materials Science & Technology 2024年第7期174卷 15-22页

作者： h.xu S.F.Yang E.h.Wang c.Y.Guo Y.S.Liu x.M.hou Y.L.Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for carbon neutrality University of Science and Technology BeijingBeijing 100083China

The oxidation behavior of ni-based superalloy Gh4742 exposed to water vapor was investigated at 900-1100℃for 50 h in Ar+20%h_(2)O,with Ar+20%O_(2)included for *** presence of h_(2)O is adverse to formation of continuous cr_(2)O_(3)oxide layer but contributes to generation of big *** on this,ni^(2+)and co^(2+)are more easily to diffuse towards the outermost oxide layer(OOL),forming non-protective ni-and co-rich oxides with high *** leads to a higher weight gain in Ar+20%h_(2)O than that in Ar+20%O_(2).At elevated temperatures,the spallation of oxide scale occurs while the consumption of cr is reduced in Ar+20%h_(2)O,and the contents of ni-and co-rich oxides at this moment are reduced in the *** oxidation mechanism was also discussed.

关键词： Gh4742 Superalloy h_(2)O Diffusion Oxidation Mechanism

In situ TEM investigation of electron irradiation and aging-induced high-density nanoprecipitates in an Mg-10Gd-3Y-1Zn-0.5Zr alloy

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Journal of Magnesium and Alloys 2024年第5期12卷 1841-1853页

作者： M.Lv h.L.Ge Q.Q.Jin x.h.Shao Y.T.Zhou B.Zhang x.L.Ma Shenyang national Laboratory for Materials Science Institute of Metal ResearchChinese Academy of Sciences72 Wenhua RoadShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Materials Science and Engineering research center Guangxi University of Science and TechnologyLiuzhou 545006China

In-situ electron irradiation and aging are applied to introduce high-density precipitates in an Mg-10Gd-3Y-1Zn-0.5Zr(GWZ1031K,wt.%)alloy to improve the *** results show that the hardness of the Mg alloy after irradiation for 10 h and aging for 9 h at 250℃ is 1.64 GPa,which is approximately 64% higher than that of the samples before being *** is mainly attributed to γ'precipitates on the basal plane after irradiation and the high-density nanoscale β'precipitates on the prismatic plane after aging,which should be closely related to the irradiation-induced homogenous *** latter plays a key role in precipitation *** result paves a way to improve the mechanical properties of metallic materials by tailoring the precipitation through irradiation and aging.

关键词： Mg alloy Electron beam irradiation hardening Precipitates In-situ TEM

Greatly enhanced corrosion/wear resistances of epoxy coating for Mg alloy through a synergistic effect between functionalized graphene and insulated blocking layer

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Journal of Magnesium and Alloys 2024年第1期12卷 332-344页

作者： Z.Y.xue x.J.Li J.h.chu M.M.Li D.n.Zou L.B.Tong School of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China

The poor corrosion and wear resistances of Mg alloys seriously limit their potential applications in various *** conventional epoxy coating easily forms many intrinsic defects during the solidification process,which cannot provide sufficient *** the current study,we design a double-layer epoxy composite coating on Mg alloy with enhanced anti-corrosion/wear properties,via the spin-assisted assembly *** outer layer is functionalized graphene(FG)in waterborne epoxy resin(WEP)and the inner layer is ce-based conversion(ce)*** FG sheets can be homogeneously dispersed within the epoxy matrix to fill the intrinsic defects and improve the barrier *** ce film connects the outer layer with the substrate,showing the transition *** corrosion rate of ce/WEP/FG composite coating is 2131 times lower than that of bare Mg alloy,and the wear rate is decreased by~90%.The improved corrosion resistance is attributed to the labyrinth effect(hindering the penetration of corrosive medium)and the obstruction of galvanic coupling *** synergistic effect derived from the FG sheet and blocking layer exhibits great potential in realizing the improvement of multi-functional integration,which will open up a new avenue for the development of novel composite protection coatings of Mg alloys.

关键词： Mg alloy Functionalized graphene Epoxy coating corrosion/wear resistance Blocking layer

The preface: Interplay of topological and magnetic orders in the Mn-Bi-Te family

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national Science review 2024年第2期11卷 6-7页

作者： Fu-chun Zhang hai-Zhou Lu x.c.xie Kavli Institute for Theoretical Sciences University of Chinese Academy of Sciences Department of Physics Southern University of Science and Technology (SUSTech) International center for Quantum Materials School of Physics Peking University

The discovery and synthesis of MnBi2Te4in 2013 initially garnered little attention [1]. Yet, the revelation of its topological properties in 2019 [2–6] sparked a surge of research into the MnBiTe family. These extensive studies are primarily driven by two objectives:the realization of a high-temperature quantum anomalous hall effect （QAhE） and the exploration of exotic phases born from the interplay of topological and magnetic orders,

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holographic dark energy in non-conserved gravity theory

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communications in Theoretical Physics 2024年第4期76卷 126-133页

作者： h r Fazlollahi Institute of Gravitation and cosmology Peoples Friendship University of Russia(RUDN University)6 Miklukho-Maklaya StMoscow117198Russia

recently, reconsidering the rastall idea T_(μ;νν)^(v)=α_(,μ) through relativistic thermodynamics gives a new form for the scalar field α which led us to construct modern modified theory of gravity debugged ‘non-conserved gravity theory’ Fazlollahi 2023 Euro. Phys. J. c 83 923. This theory unlike other modified theories of gravity cannot directly explain the current acceleration expansion in the absence of the cosmological constant and or existence of other forms of dark energy. hence, in this study we have reinvestigated holographic dark energy Ρ_(x)~h^(2) in the non-conserved theory of gravity. In this context, the density and pressure of dark energy depend on the non-conserved term and density of the dust matter field. As shown, due to non-conservation effects on large-scale structures, unlike the original holographic model, our model onsets an acceleration epoch for the current Universe satisfies observations. Moreover, the interaction and viscous scenarios are studied for this model.

关键词： non-conserved gravity covariant form of thermodynamics holographic dark energy

hierarchical OptimizationMethod for Federated Learning with Feature Alignment and Decision Fusion

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computers, Materials and continua 2024年第1期81卷 1391-1407页

作者： Li K. Wang x. Wang h. college of computer Science and Engineering North Minzu University Yinchuan 750021 China The Key Laboratory of Images & Graphics Intelligent Processing of State Ethnic Affairs commission North Minzu University Yinchuan 750021 China

In the realm of data privacy protection, federated learning aims to collaboratively train a global model. however, heterogeneous data between clients presents challenges, often resulting in slow convergence and inadequate accuracy of the *** shared feature representations alongside customized classifiers for individual clients emerges as a promising personalized solution. nonetheless, previous research has frequently neglected the integration of global knowledge into local representation learning and the synergy between global and local classifiers, thereby limiting model performance. To tackle these issues, this study proposes a hierarchical optimization method for federated learning with feature alignment and the fusion of classification decisions (FedFcD). FedFcD regularizes the relationship between global and local feature representations to achieve alignment and incorporates decision information from the global classifier, facilitating the late fusion of decision outputs from both global and local classifiers. Additionally, FedFcD employs a hierarchical optimization strategy to flexibly optimizemodel parameters. Through experiments on the Fashion-MnIST, cIFAr-10 and cIFAr-100 datasets, we demonstrate the effectiveness and superiority of FedFcD. For instance, on the cIFAr-100 dataset, FedFcD exhibited a significant improvement in average test accuracy by 6.83% compared to four outstanding personalized federated learning approaches. Furthermore, extended experiments confirmthe robustness of FedFcD across various hyperparameter values. © 2024 The Authors. Published by Tech Science Press.

关键词： data heterogeneity decision fusion feature alignment Federated learning hierarchical optimization

Microstructure evolution and shape memory behaviors of ni_(47)Ti_(44)nb_(9)alloy subjected to multistep thermomechanical loading with different prestrain levels

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Journal of Materials Science & Technology 2024年第4期171卷 80-93页

作者： Y.h.Zhang h.Li Z.W.Yang x.Liu Q.F.Gu State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of high-Performance Precision Forming Technology and Equipment Northwestern Polytechnical UniversityXi’an 710072China

ni_(47)Ti_(44)nb_(9)shape memory alloy(SMA)is a promising material in the aerospace field due to its wide transformation *** application of shape memory effect depends on multistep thermomechan-ical loading,viz.,low-temperature deformation and subsequent heating to ***-temperature deformation prestrain plays a pivotal role in shape memory properties tailoring of SMA ***,microstructure evolution and deformation mechanisms of ni_(47)Ti_(44)nb_(9)SMA subjected to vari-ous prestrain levels are still *** this end,microstructure evolution and shape memory behaviors of ni_(47)Ti_(44)nb_(9)alloy subjected to multistep thermomechanical loading with prestrain levels of 8%-16%at-28℃(M_(s)+30℃)were *** results demonstrate that the stress-strain curve of the specimen exhibits four distinct stages at a maximal prestrain of 16%.Whereas stageⅡand stageⅢend at prestrains of∼8%and∼12%,*** stageⅡ,the stress-induced martensitic transformation is accompanied by the dislocation slip of the niTi matrix andβ-nb *** stageⅢ,in addition to the higher density of dislocations and further growth of stress-induced martensite variants(SIMVs),(001)compound twins are introduced as a result of the(001)deformation twinning in stress-induced ***{20-1}martensite twins are gradually introduced in stageⅣ.correspondingly,after subsequent unloading and heating,a higher density ofnaustenite twins form in the specimen with a larger prestrain of 16%.With increasing prestrain from 8%to 16%,the recoverable strainε_(re)^(T)upon heating increases first and then ***ε_(re)^(T)obtains a maximum of 7.03%at 10%prestrain and de-creases to 6.17%at 16%*** increase ofε_(re)^(T)can be attributed to the formation of new SIMVs,the further growth of existing SIMVs,and the recoverable(001)compound *** the decrease ofε_(re)^(T)is mainly associated with the irrecoverable strain by{20−1}martensite *** effe

关键词： ni_(47)Ti_(44)nb_(9)shape memory alloy Wide transformation hysteresis Thermomechanical loading Microstructure evolution Shape memory behaviors Stress-induced martensitic transformation Deformation twinning

reactive destabilization and bidirectional catalyzation for reversible hydrogen storage of LiBh_(4) by novel waxberry-like nano-additive assembled from ultrafine Fe_(3)O_(4) particles

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Journal of Materials Science & Technology 2024年第6期173卷 63-71页

作者： S.Wang M.h.Wu Y.Y.Zhu Z.L.Li Y.x.Yang Y.Z.Li h.F.Liu M.x.Gao Department of Material Science Shenzhen MSU-BIT UniversityShenzhen 518172China State Key Laboratory of Silicon and Advanced Semiconductor Materials&School of Materials Science and Engineering Zhejiang UniversityHangzhou 310027China Institute of resources Utilization and rare Earth Development State Key Laboratory of Rare Metals Separation and Comprehensive UtilizationGuangdong Provincial Key Laboratory of Rare Earth Development and ApplicationGuangdong Academy of SciencesGuangzhou 510650China Institute of Science and Technology for new Energy Xi’an Technological UniversityXi’an 710021China national Supercomputing center in Shenzhen Shenzhen 518055China

LiBh_(4) containing 18.5 wt.%h_(2) is an attractive high-capacity hydrogen storage material,however,it suffers from high operation temperature and poor ***,a novel and low-cost bifunctional additive,waxberry-like Fe_(3)O_(4) secondary nanospheres assembled from ultrafine primary Fe_(3)O_(4) nanoparticles,is synthesized,which exhibits significant destabilization and bidirectional catalyzation towards(de)hydrogenation of LiBh_(4).With an optimized addition of 30 wt.% waxberry-like Fe_(3)O_(4),the system initiated dehydrogenation below 100℃ and released a total of 8.1 wt.%h_(2) to 400℃.After 10 cycles,a capacity retention of 70% was achieved,greatly superior to previously reported oxides-modified *** destabilizing and catalyzing mechanisms of waxberry-like Fe_(3)O_(4) on LiBh_(4) were systematically analyzed by phase and microstructural evolutions during dehydrogenation and hydrogenation cycling as well as density functional theory(DFT)*** present work provides new insights in developing advanced nano-additives with unique structural and multifunctional designs towards LiBh4 hydrogen storage.

关键词： LiBh_(4) hydrogen storage Waxberry-like Fe_(3)O_(4) Destabilization catalysis