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Journal of Materials Science & Technology 2022年第1期96卷 85-93页

作者： Q.yan B.Chen L.Cao K.y.liu S.Li L.Jia k.kondoh J.S.Li State key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China School of Materials Science and Engineering Xi’an University of TechnologyXi’an 710048China Joining and Welding Research Institution Osaka University11-1 MihogaokaIbarakiOsaka 567-0047Japan

In order to construct quasi-continuously networked reinforcement in titanium(Ti)matrix composites,in this study,Ti-6 Al-4 V spherical powders were uniformly coated with a graphene nanosheet(GNS)layer by high energy ball milling and then consolidated by spark plasma sintering.Results showed that the GNS layer on the powder surface inhibited continuous metallurgy bonding between powders during sintering,which led to the formation of quasi-networked hybrid reinforcement structure consisting of insitu Ti C and remained GNSs.The networked GNSs/Ti64 composite possessed noticeably higher tensile strength but similar ductility to the Ti64 alloy,leading to both better tensile strength and ductility than the GNSs/Ti composite with randomly dispersed GNSs and Ti C.The formation mechanism and the fracture mechanism of the networked hybrid reinforcement were discussed.The results provided a method to fabricate Ti matrix composites with high strength and good ductility.

关键词： Titanium matrix composites(TMCs) Graphene Network structure Strength Ductility

Finite Element Prediction of the Thermal Conductivity of GNP/Al Composites

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Acta Metallurgica Sinica(English Letters) 2022年第5期35卷 825-838页

作者： X.S.yang L.Zhou K.y.liu Z.y.liu Q.Z.Wang B.L.Xiao Z.y.Ma School of Electromechanical and Automotive Engineering Yantai UniversityYantai264005China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

A 3 D multi-scale finite element model was developed to predict the effective thermal conductivity of graphene nanoplatelet(GNP)/Al composites.The factors influencing the effective thermal conductivity of the GNP/Al composites were investigated,including the orientation,shape,aspect ratio,configuration and volume fraction of GNPs.The results show that GNPs shape has a little influence on the thermal conductivity of GNP/Al composites,and composites with elliptic GNPs have the highest thermal conductivity.In addition,with increasing the aspect ratio of GNPs,the thermal conductivity of GNP/Al composites increases and finally tends to be stable.The GNPs configuration strongly influences the thermal conductivity of GNP/Al composites,and the thermal conductivity of the composites with layered GNPs is the highest among the five configurations.The effective thermal conductivity is sensitive to volume fraction of GNPs.Ideally,when the volume fraction of layered GNPs reaches 1.54%,the thermal conductivity of GNP/Al composites is as high as 400 W/m k.The findings of this study could provide a good theoretical basis for designing high thermal conductivity GNP/Al composites.

关键词： Multi-scale finite element model Thermal conductivity GNP/Al composites Shape Aspect ratio Configuration

Validation of an objective scar pigmentation measurement by using a spectrocolorimeter

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Validation of an objective scar pigmentation measurement by ...

Numerical study on size effect of ring specimen under Brazilian test

第八届全国烧伤外科学年会

作者： Cecilia W．P．Li-Tsang Joy C．M．Lau Sally K.y.liu Department of Rehabilitation Sciences The Hong Kong Polytechnic UniversityHung HomKowloonHong KongPR China Occupational Therapy Department Pamela Youde Nethersole Eastern HospitalHospital AuthorityChai WanHong KongPR China

＜正＞Scar pigmentation changes throughout its maturation process and it is often used as one of the indicators for scar maturation,yet it is often rated subjectively.The purpose of this study was to investigate the application of a commercial spectrocolorimeter to produce a reliable measurement on scar pigmentation.Commission Internationale de l’Eclairage （CIE） model of color has been adopted in this study for measurement of scar pigmentation 24 patients with hypertrophic scars at different stages of maturation were selected for the study,were inspected by two therapists using the Vancouver scar scale （VSS） and then using spectrocolorimeter for inter-rater reliability.The measurements were taken after 30 min by the same group of therapists （test-retest reliability）.Results indicated that the inter-rater reliability among the three therapists was satisfactory,with intra-class correlation coefficient （ICC）（2,2） from 0.50 to 0.99 in all the three color parameters.The test-retest reliability of the spectrocolorimeterwas satisfactory with ICC （3,6） ranged from 0.95 to 0.99.Asignificant difference was also noted between the measurements of normal skin and hypertrophic scar （P＜0.00,t-values:from 2.78 to 0.05,d.f.:from 29.7 to 46.00） in all color parameters,except the chroma C*.We also found a positive relationship between VSS scores and the spectrocolorimeter readings.The spectrocolorimeter is found to be a reliable instrument to quantify scar pigmentation and to differentiate normal skin and scar tissue.With further studies,the constructs of scar properties could further be explored using this spectrocolorimeter. 2003 Elsevier Ltd and ISBI.All rights reserved.

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Numerical study on size effect of ring specimen under Brazil...

State-of-the-art survey on digital twin implementations

The International young Scholars’ Symposium on Rock Mechanics

作者： W.B.liu B.G.liu K.y.liu School of Civil Engineering and Architecture,Beijing Jiaotong University,Beijing,China

Numerical simulations of uniaxial tension and Brazilian test with ring specimen have been conducted to evaluate the effects of internal radius on the tensile strength of brittle and heterogeneous rock. It was done by using the Rock Failure Process Analysis program(RFPA).Numerical ring specimens with different ratios of internal radius to external radius(r/R=0.1,0.2,0.3,0.4,0.5 and 0.6),and a rectangular specimen with the same mechanical parameters have been numerically analyzed.The numerical simulations not only qualitatively reproduce the experimentally observed pre- and post-peak failure phenomena of the loaded specimens,but also provide a quantitative evaluation of the influence of the internal radius on the tensile strength characteristics.The optimal ratio of internal radius to external radius adopted in experiment was determined and the relation between internal radius and tensile strength of specimen was set up by analyzing the simulation results.

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Advances in Manufacturing 2022年第1期10卷 1-23页

作者： y.k.liu S.k.Ong A.y.C.Nee Department of Mechanical Engineering National University of Singapore9 Engineering Drive 1Singapore 117575Singapore

Digital twin(DT)has garnered attention in both industry and academia.With advances in big data and internet of things(IoTs)technologies,the infrastructure for DT implementation is becoming more readily available.As an emerging technology,there are both potential and challenges.DT is a promising methodology to leverage the modern data explosion to aid engineers,managers,healthcare experts and politicians in managing production lines,patient health and smart cities by providing a comprehensive and high fidelity monitoring,prognostics and diagnostics tools.New research and surveys into the topic are published regularly,as interest in this technology is high although there is a lack of standardization to the definition of a DT.Due to the large amount of information present in a DT system and the dual cyber and physical nature of a DT,augmented reality(AR)is a suitable technology for data visualization and interaction with DTs.This paper seeks to classify different types of DT implementations that have been reported,highlights some researches that have used AR as data visualization tool in DT,and examines the more recent approaches to solve outstanding challenges in DT and the integration of DT and AR.

关键词： Industry 4.0 Internet of thing(IoT) Cyberphysical systems Digital twin(DT) Augmented reality(AR)

STCF conceptual design report (Volume 1): Physics & detector

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Frontiers of physics 2024年第1期19卷 1-154页

作者： M.Achasov X.C.Ai L.P.An R.Aliberti Q.An X.Z.Bai y.Bai O.Bakina A.Barnyakov V.Blinov V.Bobrovnikov D.Bodrov A.Bogomyagkov A.Bondar I.Boyko Z.H.Bu F.M.Cai H.Cai J.J.Cao Q.H.Cao X.Cao Z.Cao Q.Chang k.T.Chao D.y.Chen H.Chen H.X.Chen J.F.Chen k.Chen L.L.Chen P.Chen S.L.Chen S.M.Chen S.Chen S.P.Chen W.Chen X.Chen X.F.Chen X.R.Chen y.Chen y.Q.Chen H.y.Cheng J.Cheng S.Cheng T.G.Cheng J.P.Dai L.y.Dai X.C.Dai D.Dedovich A.Denig I.Denisenko J.M.Dias D.Z.Ding L.y.Dong W.H.Dong V.Druzhinin D.S.Du y.J.Du Z.G.Du L.M.Duan D.Epifanov y.L.Fan S.S.Fang Z.J.Fang G.Fedotovich C.Q.Feng X.Feng y.T.Feng J.L.Fu J.Gao y.N.Gao P.S.Ge C.Q.Geng L.S.Geng A.Gilman L.Gong T.Gong B.Gou W.Gradl J.L.Gu A.Guevara L.C.Gui A.Q.Guo F.k.Guo J.C.Guo J.Guo y.P.Guo Z.H.Guo A.Guskov k.L.Han L.Han M.Han X.Q.Hao J.B.He S.Q.He X.G.He y.L.He Z.B.He Z.X.Heng B.L.Hou T.J.Hou y.R.Hou C.y.Hu H.M.Hu k.Hu R.J.Hu W.H.Hu X.H.Hu y.C.Hu J.Hua G.S.Huang J.S.Huang M.Huang Q.y.Huang W.Q.Huang X.T.Huang X.J.Huang y.B.Huang y.S.Huang N.Hüsken V.Ivanov Q.P.Ji J.J.Jia S.Jia Z.k.Jia H.B.Jiang J.Jiang S.Z.Jiang J.B.Jiao Z.Jiao H.J.Jing X.L.kang X.S.kang B.C.ke M.kenzie A.khoukaz I.koop E.kravchenko A.kuzmin y.Lei E.Levichev C.H.Li C.Li D.y.Li F.Li G.Li G.Li H.B.Li H.Li H.N.Li H.J.Li H.L.Li J.M.Li J.Li L.Li L.Li L.y.Li N.Li P.R.Li R.H.Li S.Li T.Li W.J.Li X.Li X.H.Li X.Q.Li X.H.Li y.Li y.y.Li Z.J.Li H.Liang J.H.Liang y.T.Liang G.R.Liao L.Z.Liao y.Liao C.X.Lin D.X.Lin X.S.Lin B.J.liu C.W.liu D.liu F.liu G.M.liu H.B.liu J.liu J.J.liu J.B.liu k.liu K.y.liu k.liu L.liu Q.liu S.B.liu T.liu X.liu y.W.liu y.liu y.L.liu Z.Q.liu Z.y.liu Z.W.liu I.Logashenko y.Long C.G.Lu J.X.Lu N.Lu Q.F.Lü y.Lu y.Lu Z.Lu P.Lukin F.J.Luo T.Luo X.F.Luo y.H.Luo H.J.Lyu X.R.Lyu J.P.Ma P.Ma y.Ma y.M.Ma F.Maas S.Malde D.Matvienko Z.X.Meng R.Mitchell A.Nefediev y.Nefedov S.L.Olsen Q.Ouyang P.Pakhlov G.Pakhlova X.Pan y.Pan E.Passemar y.P.Pei H.P.Peng L.Peng X.y.Peng X.J.Peng k.Peters S.Pivovarov E.Pyata B.B.Qi y.Q.Qi W.B.Qian y.Qian C.F.Qiao J.J.Qin J.J.Qin L.Q.Qin X.S.Qin T.L.Qiu J.Rademacker C.F.Redmer H.y.Sang Anhui University Hefei 230039China Beihang University Beijing 100191China Budker Institute of Nuclear Physics Novosibirsk 630090Russia CAS key Laboratory of Theoretical Physics Institute of Theoretical PhysicsChinese Academy of SciencesBeijing 100190China Cavendish Laboratory University of CambridgeJJ Thomson AveCambridge CB30HEUnited Kingdom Central China Normal University Wuhan 430079China Central South University Changsha 410083China China University of Geosciences Wuhan 430074China China University of Mining and Technology Xuzhou 221116China École Polytechnique Fédérale de Lausanne(EPFL) LausanneSwitzerland Fudan University Shanghai 200433China Goethe University Frankfurt D-60325 Frankfurt am MainGermany Guangxi Normal University Guilin 541004China Guangxi Uninversity Nanning 530004China Hangzhou Institute for Advanced Study UCASHangzhou 310024China Hebei Normal University Shijiazhuang 050024China Hebei University Baoding 071002China Hefei University of Technology Hefei 230601China Helmholtz Institute Mainz Staudinger Weg 18D-55099 MainzGermany Henan Normal University Xinxiang 453007China Henan University Kaifeng 475004China High Energy Physics Center Chung-Ang UniversitySeoul 06974Korea Higher School of Economy 11 Pokrovsky Bulvar Moscow 109028Russia Huangshan University Huangshan 245000China Hubei University of Automotive Technology Shiyan 442002China Hunan Normal University Changsha 410081China Hunan University of Science and Technology Xiangtan 411201China Hunan University Changsha 410082China Indiana University BloomingtonIndiana 47405USA Inner Mongolia University Hohhot 010021China Institute of Advanced Science Facilities Shenzhen 518107China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China Institute of Physics Academia SinicaTaipeiTaiwan 11529China Institute of Theoretical Physics Chinese Academy of SciencesBeijing 100190China Jilin University Changch

The superτ-charm facility(STCF)is an electron–positron collider proposed by the Chinese particle physics community.It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of 0.5×10^(35) cm^(–2)·s^(–1) or higher.The STCF will produce a data sample about a factor of 100 larger than that of the presentτ-charm factory—the BEPCII,providing a unique platform for exploring the asymmetry of matter-antimatter(charge-parity violation),in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions,as well as searching for exotic hadrons and physics beyond the Standard Model.The STCF project in China is under development with an extensive R&D program.This document presents the physics opportunities at the STCF,describes conceptual designs of the STCF detector system,and discusses future plans for detector R&D and physics case studies.

关键词： electron–positron collider tau-charm region high luminosity STCF detector conceptual design

Harmonic balance-based approach for optimal time delay to control unstable periodic orbits of chaotic systems

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Acta Mechanica Sinica 2020年第4期36卷 918-925页

作者： y.M.Chen Q.X.liu J.k.liu Department of Mechanics Sun Yat-sen UniversityGuangzhou 510275China

As a classical technique for chaos suppression,the time-delayed feedback controlling strategy has been widely developed by stabilizing unstable periodic orbits(UPOs)embedded in chaotic systems.A critical issue for achieving high controlling precision is to search for an appropriate time delay.This paper proposes a simple yet effective approach,based on incremental harmonic balance method,to determine the optimal time delay in the delayed feedback controller.The time delay is adjusted within the iterative scheme provided by the proposed method,and finally converges to the period of the target UPO.As long as the optimal time delay is fixed,moreover,the attained solution makes it quite convenient to analyze its stability according to the Floquet theory,which further provides the effective interval of the feedback gain.

关键词： Chaos control Unstable periodic orbit Delayed feedback Optimal time delay Incremental harmonic balance method

Uncovering the softening mechanism and exploring the strengthening strategies in extremely fine nanograined metals:A molecular dynamics study

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Journal of Materials Science & Technology 2022年第14期109卷 186-196页

作者： H.R.Peng Z.y.Jian C.X.liu L.k.Huang y.M.Ren F.liu School of Materials and Chemical Engineering Xi’an Technological UniversityXi’an 710021China State key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

The strength of polycrystalline metals increases with decreasing grain size,following the classical HallPetch relationship.However,this relationship fails when softening occurs at very small grain sizes(typically less than 10 to 20 nm),which limits the development of ultrahigh-strength materials.In this work,using columnar-grained nanocrystalline Cu-Ag‘samples’,molecular dynamics simulations were performed to investigate the softening mechanism and explore the strengthening strategies(e.g.,formation of solid solution or grain boundary(GB)segregation)in extremely fine nanograined metals.Accordingly,the softening of pure metals is induced by atomic sliding in the GB layer,rather than dislocation activities in the grain interior,although both occur during deformation.The solid solution lowers the stacking fault energy and increases the GB energy,which leads to the softening of NC metals.GB segregation stabilizes GB structures,which causes a notable improvement in strength,and this improvement can be further enhanced by optimizing the solute concentration and GB excess.This work deepens the understanding of the softening mechanism due to atomic sliding in the GB layer and the strengthening mechanism arising from tailoring the GB stability of immiscible alloys and provides insights into the design of ultrahighstrength materials.

关键词： Softening Strengthening Cu-Ag alloy Molecular dynamics Nanocrystalline

The roles of polymer-graphene interface and contact resistance among nanosheets in the effective conductivity of nanocomposites

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Applied Mathematics and Mechanics(English Edition) 2023年第11期44卷 1941-1956页

作者： y.ZARE k.y.RHEE Department of Mechanical Engineering(Bk21 Four) College of EngineeringKyung Hee UniversityYongin 17104Republic of Korea

The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial properties are expressed by the effective levels of the inverse aspect ratio and the filler volume fraction.Moreover,the resistances of components in the contact regions are used to define the contact resistance,which inversely affects the effective conductivity.The obtained model is utilized to predict the effective conductivity for some examples.The discrepancy of the effective conductivity at various ranks of all factors is clarified.The interfacial conductivity directly controls the effective conductivity,while the filler conductivity plays a dissimilar role in the effective conductivity,due to the incomplete interfacial adhesion.A high operative conductivity is also achieved by small contact distances and high interfacial properties.Additionally,big contact diameters and little tunnel resistivity decrease the contact resistance,thus enhancing the effective conductivity.

关键词： polymer nanocomposite operative conductivity graphene interfacial property contact region

Designing hetero-structured ultra-strong and ductile Zr-2.5Nb alloys:Utilizing the grain size-dependent martensite transformation during quenching

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Journal of Materials Science & Technology 2022年第30期125卷 198-211页

作者： S.y.liu J.y.Zhang J.kuang X.y.Bao D.D.Zhang C.L.Zhang J.k.yang G.liu J.Sun State key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

To further improve the service performance of Zr-2.5Nb alloy worked as pressure tubes in pressurized heavy water reactors,more investigation about the microstructure and thermomechanical processing route of Zr-2.5Nb alloy need to be conducted.In this work,a hetero-structured Zr-2.5Nb alloy was prepared by applying a novel technique.Microstructure analysis reveals that the alloy exhibits a grain sizedependent martensite substructure transition during post-rolling quenching.The hetero-structure consists of equiaxed primaryαgrains and the lamellae groups containing both parallelα’dislocation martensite andα’twin martensite.Compared with the previously reported Zr-Nb alloys,the present Zr-2.5Nb alloys manifest the highest yield strength(∼710 MPa),together with a high ultimate tensile strength(∼844 MPa)and good ductility(∼17.1%).The enhanced mechanical properties are found to arise from the properly controlled fraction/size of the two types of martensite,which not only significantly strengthens the alloy but also contributes to a stronger strain hardening.A model based on the grain-size-dependent critical resolved shear stress for dislocation slip and twinning has been proposed to explain theα’martensite substructures transition at a critical grain size dc=3.3μm.Below this size,the critical resolved shear stress(CRSS)for twinning is higher than that for theslip.Thus,theα’dislocation martensite is more favorable to form.Otherwise,theα’twin martensite would exhibit a high activity.The present work indicates that making use of the grain size-dependent martensite transformation to tailor the heterostructure in Zr alloys is an effective strategy to overcome the strength–ductility trade-off in the material.

关键词： Zr-Nb alloys Heterogeneous structure Martensitic transformation Grain size Strength