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Journal of Materials science & Technology 2011年第1期27卷 15-21页

作者： h.s. liu B. Zhang G.P. Zhang shenyang National Laboratory for Materials science Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Key Laboratory for Anisotropy and Texture of Materials of Ministry of Education School of Materials & Metallurgy Northeastern University Shenyang 110004 China

Al/Mg alloy multilayered composites were produced successfully at the lower temperature（280 C） by accumulative roll bonding（ARB） processing *** microstructures of Al and Mg alloy layers were characterized by scanning electron microscopy and transmission electron *** hardness and three-point bending tests were conducted to investigate mechanical properties of the *** is found that Vickers hardness,bending strength and stiffness modulus of the Al/Mg alloy multilayered composite increase with increasing the ARB *** and crack propagation along the interface are the two main failure modes of the multilayered composite subjected to bending *** and fracture mechanisms of the composite are analyzed.

关键词： Accumulative roll bonding(ARB) Al/Mg alloy multilayered composite Ultra-fine grains hardness Bending properties

First-principles Calculation Assisted Thermodynamic Modeling of Ti-Co-Cu Ternary system

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Journal of Materials science & Technology 2010年第4期26卷 317-326页

作者： Y.J. Yang X.M. Tao W.J. Zhu Z.h. Long h.s. liu Z.P. Jin school of Materials science and Engineering Central South University Changsha 410083 China Key Lab of Non-ferrous Metal science and Engineering Ministry of Education Changsha 410081 China

Thermodynamic assessment of Ti-Co-Cu ternary system h.s.been carried out by combining first-principle calculation and CALPhAD method. Firstly, formation enthalpies of stable and hypoth.s.zed compounds were calculated by first-principles method. Then, based on reported experimental information, a thermodynamic description of the Ti-Co-Cu ternary system was performed. solution ph.s.s were treated as substitutional solutions of which excess Gibbs energies were formulated by Redlich-Kister polynomial, and the intermediate ph.s.s were described with.s.blattice models. All measured isothermal sections were reasonably reproduced. In addition, liquidus projection of th.s.ternary system was further calculated, which may be useful for relevant materials processing.

关键词： First-principle CALPhAD Thermodynamic modeling

DETERMINATION OF IsOThERMAL sECTION OF Fe-Ni-Zr TERNARY sYsTEM AT 1198K

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Acta Metallurgica sinica(English Letters) 2007年第6期20卷 398-402页

作者： G.J. Zhou s. Jin L.B. liu h.s. liu Z.P. Jin school of Materials science and Engineering Central-South UniversityChangsha 410083 China

The isothermal section of Fe-Ni-Zr ternary system at 1198K was experimentally determined using diffusion triple technique together with.s.anning electron microscopy （sEM） and electron probe microanalysis （EPMA ）. The results indicate that there are seven binary intermetallic ph.s.s, Fe2Zr, FeZr2, Nir2, NiZr, Ni10Zr7, Ni7Zr2 and Ni5Nr, found in the temary system, the binary compounds NiZr2 and FeZr2 show a homogeneity range and form a continuous solid solution, namely （Fe, Ni）Zr2 Five three-ph.s. sections, γ（Fe,Ni）＋ Ni3Zr2 ＋ Ni5Zr,γ（Fe, Ni）＋ Ni7Zr2 ＋ Ni10Zr7, γ（Fe,Ni）＋ Fe2Zr ＋ Ni10Zr7, （Fe,Ni）Zr2 ＋ Fe2Zr ＋ Nil0Zr7, and （Fe,Ni）Zr2 ＋ NiZr ＋ Ni10Zr7, exist in the isothermal section. No ternary compound is observed.

关键词： Fe-Ni-Zr diffusion triple isothermal section ph.s. diagram

Linear OPF-based Robust Dynamic Operating Envelopes with Uncertainties in Unbalanced Distribution Networks

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Journal of Modern Power systems and Clean Energy 2024年第4期12卷 1320-1326页

作者： Bin liu Julio h.Braslavsky Nariman Mahdavi Energy Centre Commonwealth Scientific and Industrial Research Organisation(CSIRO)Newcastle 2300Australia the Network Planning Division TransgridSydney 2000Australia the Energy systems Program Energy CentreCommonwealth Scientific and Industrial Research Organisation(CSIRO)Newcastle 2300Australia

Dynamic operating envelopes(DOEs),as key enablers to facilitate distributed energy resource(DER)integration,have attracted increasing attention in the past ***,uncertainties,which may come from load forecasting errors or inaccurate network parameters,have been rarely discussed in DOE calculation,leading to compromised quality of the h.s.ing capacity allocation *** letter studies how to calculate DOEs that are immune to such uncertainties based on a linearised unbalanced three-ph.s. optimal power flow(UTOPF)*** uncertain parameters constrained by norm balls,formulations for calculating robust DOEs(RDOEs)are presented along with discussions on their *** cases,including a 2-bus illustrative network and a representative Australian network,are tested to demonstrate the effectiveness and efficiency of the proposed approach.

关键词： Distributed energy resource(DER) dynamic operating envelope(DOE) feasible region robust optimisation uncertainty modelling unbalanced optimal power flow

spontaneous Recovery in Directed Dynamical Networks

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Engineering 2024年第6期37卷 208-214页

作者： Xueming liu Xian Yan h.Eugene stanley school of Artificial Intelligence and Automation&The MOE Engineering Research Center of Autonomous Intelligent Unmanned systems&the Key Laboratory of Image Processing Huazhong University of Science and TechnologyWuhan 430074China Center for Polymer studies Department of PhysicsBoston UniversityBostonMA 02215USA

Complex networked systems,which range from biological systems in the natural world to infrastructure systems in the human-made world,can exhibit spontaneous recovery after a failure;for example,a brain may spontaneously return to normal after a seizure,and traffic flow can become smooth again after a *** studies on the spontaneous recovery of dynamical networks have been limited to undirected ***,most real-world networks are *** fill th.s.gap,we build a model in which nodes may alternately fail and recover,and we develop a theoretical tool to analyze the recovery properties of directed dynamical *** find that the tool can accurately predict the final fraction of active nodes,and the prediction accuracy decreases as the fraction of bidirectional links in the network increases,which emph.s.zes the importance of directionality in network *** to different initial states,directed dynamical networks may show alternative stable states under the same control parameter,exhibiting h.s.eresis *** addition,for networks with finite sizes,the fraction of active nodes may jump back and forth between high and low states,mimicking repetitive failure-recovery *** findings could help clarify the system recovery mechanism and enable better design of networked systems with high resilience.

关键词： Network resilience Directed dynamical networks spontaneous recovery

saliency-guided meta-hallucinator for few-shot learning

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science China(Information sciences) 2024年第10期67卷 189-210页

作者： hongguang ZhANG Chun liu Jiandong WANG Linru MA Piotr KONIUsZ Philip h.s.TORR Lin YANG systems Engineering Institute Academy of Military Sciences Data61 Commonwealth Scientific and Industrial Research Organisation Australian National University Oxford University

Learning novel object concepts from limited samples remains a considerable challenge in deep learning. The main directions for improving the few-shot learning models include(i) designing a stronger backbone,(ii) designing a powerful(dynamic) meta-classifier, and(iii) using a larger pre-training set obtained by generating or hallucinating additional samples from the small scale dataset. In th.s.paper, we focus on item(iii) and present a novel meta-hallucination strategy. Presently, most image generators are based on a generative network(i.e., GAN) that generates new samples from the captured distribution of images. however, such networks require numerous annotated samples for training. In contrast, we propose a novel saliency-based end-to-end meta-hallucinator, where a saliency detector produces foregrounds and backgrounds of support images. such images are fed into a two-stream network to hallucinate feature samples directly in the feature space by mixing foreground and background feature samples. Then, we propose several novel mixing strategies that improve the quality and diversity of hallucinated feature ***, as not all saliency maps are meaningful or high quality, we further introduce a meta-hallucination controller that decides which foreground feature samples should participate in mixing with backgrounds. To our knowledge, we are the first to leverage saliency detection for few-shot learning. Our proposed network achieves state-of-the-art results on publicly available few-shot image classification and anomaly detection benchmarks, and outperforms competing sample mixing strategies such as the so-called Manifold Mixup.

关键词： few-shot learning saliency detection object recognition anomaly detection computer vision

Construction of 2D/2D Ti_(3)C_(2)T_(x)MXene/Cds heterojunction with photothermal effect for efficient photocatalytic hydrogen production

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Journal of Materials science & Technology 2024年第4期171卷 1-9页

作者： T.Y.huang Z.Yang s.Y.Yang Z.h.Dai Y.J.liu J.h.Liao G.Y.Zhong Z.J.Xie Y.P.Fang s.s.Zhang Key Laboratory for Biobased Materials and Energy of Ministry of Education Guangdong Laboratory for Lingnan Modern AgricultureCollege of Materials and EnergySouth China Agricultural UniversityGuangzhou 510643China school of Ph.s.cs and Optoelectronics South China University of TechnologyGuangzhou 510640China school of Chemical Engineering and Energy Technology Guangdong Provincial Key Laboratory of Distributed Energy SystemsDongguan University of TechnologyDongguan 523808China

The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic *** photocatalysts with full-spectrum absorption through.s.rface engineering is an effective approach to fully harnessing light energy in semiconductor ***,a novel stable Ti_(3)C_(2)T_(x)MXene/Cds heterojunction catalyst is obtained by in-situ epitaxial growth of two-dimensional(2D)Cds nanosheets on 2D MXene interface via a solvothermal *** exceptional light absorption properties of MXene confer outstanding full-spectrum driven photocat-alytic hydrogen evolution capability upon the heterogeneous *** unique 2D/2D structure effectively mitigated the recombination of photogenerated carriers,enhancing the photocatalytic performance of the ***,the composite catalyst exhibits a significantly higher surface temperature of 80.4℃under visible light irradiation at an intensity of 0.1 W/cm^(2),which is 1.84 times higher than that of *** irradiation of visible and near infrared light,the composite catalyst with photothermal ef-fect demonstrates a remarkable hydrogen evolution rate of 65.4 mmol g^(-1)h^(-1),which is 7.2 times higher than that of Cds *** study introduces a novel approach for constructing full-spectrum absorption catalysts and expands the application of the photothermal effect in photocatalytic hydrogen evolution research.

关键词： Two-dimensional structure heterostructure Photothermal effect Photocatalyst hydrogen evolution

PERIODIC sYsTEMs WITh TIME DEPENDENT MAXIMAL MONOTONE OPERATORs

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Acta Mathematica scientia 2024年第4期44卷 1280-1300页

作者： Zhenhai liu Nikolaos s.PAPAGEORGIOU Center for Applied Mathematics of Guangri Yulin Normal UniversityYulin 537000China Guangri Key Laboratory of Universities Optimization Control and Engineering Calculation College of Mathematics and PhysicsGuangri Minzu UniversityNanning 530006China Department of Mathematics National Technical UniversityZografou Campus15780 AthensGreece

We consider a first order periodic system in R^(N),involving a time dependent maximal monotone operator which need not have a full domain and a multivalued *** prove the existence theorems for both the convex and nonconvex *** also show the existence of extremal periodic solutions and provide a strong relaxation ***,we provide an application to nonlinear periodic control systems.

关键词： periodic boundary condition time-dependent maximal monotone operator convex and nonconvex problems extremal solutions strong relaxation

Estimating Critical Clearing Time of Grid Faults Using DA of state-Reduction Model of Power systems

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CsEE Journal of Power and Energy systems 2024年第2期10卷 807-820页

作者： Yang liu Zhongyang Chen huanjin Yao Lin Yi Q.h.Wu school of Electric Power Engineering South China University of TechnologyGuangzhou 510640China China southern Power Grid Research Institute Guangzhou 510663China

Th.s.paper proposes a critical clearing time (CCT) estimation method by the domain of attraction (DA) of a state-reduction model of power systems using sum of squares (sOs) programming. By exploiting the property of the Jacobian matrix and the structure of the boundary of the DA, it is found the DA of the state-reduction model and that of the full model of a power system are topological isomorph.s.. There are one-to-one correspondence relationships between the number of equilibrium points, the type of equilibrium points, and solutions of the two system models. Based on th.s. findings, an expanding interior algorithm is proposed with.s.s programming to estimate the DA of the state-reduction model. state trajectories of the full model can be transformed to th.s. of the state-reduction model by orthogonal or equiradius projection. In th.s.way, CCT of a grid fault is estimated with the DA of the state-reduction model. The calculational burden of sOs programming in the DA estimation using the state-reduction model is rather small compared with using the full model. simulation results show the proposed expanding interior algorithm is able to provide a tight estimation of DA of power systems with higher accuracy and lower time costs.

关键词： Critical clearing time domain of attraction expanding interior algorithm state-reduction model sOs programming

Thermo-kinetic characteristics on stabilizing hetero-ph.s. interface of metal matrix composites by crystal plasticity finite element method

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Journal of Materials science & Technology 2024年第2期169卷 53-67页

作者： Y.B.Zhang s.J.song F.liu state Key Laboratory of solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China

Using dislocation-based constitutive modeling in three-dimension crystal plasticity finite element(3D CPFE)simulations,co-deformation and instability of hetero-ph.s. interface in different material systems were herein studied for polycrystalline metal matrix composites(MMCs).Local stress and strain fields in two types of 3layer MMCs such as fcc/fcc Cu-Ag and fcc/bcc Cu-Nb have been predicted under simple compressive ***,more severe strain-induced interface instability can be observed in the fcc/bcc systems than in the fcc/fcc systems upon refining to metallic nanolayered composites(MNCs).By detailed analysis of stress and strain localization,it h.s.been demonstrated that the interface instability is always accompanied by high.s.ress concentration,i.e.,thermodynamic characteristics,or high.s.rain prevention i.e.,kinetic characteristics,at the hetero-ph.s. *** then follows that the thermodynamic driving forceG and the kinetic energy barrier Q during dislocation and shear banding can be adopted to classify the deformation modes,following the so-called thermo-kinetic *** by inserting a high density of high-energy interfaces into the Cu-Nb composites,such thermo-kinetic integration at the hetero-ph.s. interface allows a successful establishment of MMCs with the high△G-high Q deformation mode,which ensures high hardening and uniform strain distri-bution,th.s.efficiently suppressing the shear band,stabilizing the hetero-ph.s. interface,and obtaining an exceptional combination in strength and *** hetero-ph.s. interface ch.s.n by a couple of thermodynamics and kinetics can be defined as breaking the thermo-kinetic correlation and h.s.been proposed for artificially designing MNCs.

关键词： Thermodynamics and kinetics Ph.s.cs-based constitutive modeling hetero-ph.s. interface Crystal plasticity finite element