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Molecular beam epitaxy.growth of.monolay.r hexagonal MnTe_(2)on Si(111)substrate

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Chinese Phy.ics B 2021年第12期30卷 142-147页

作者： S lu K Peng P D Wang A X Chen W Ren X W f.ng y.Wu Z y.Li H f.Li f.y.Cheng K L Xiong J y.y.ng J Z Wang S A Ding y.P Jiang) L Wang Q Li f.S Li L f.Chi Institute of.f.nctional Nano&Sof. Materials(f.NSOM) Soochow UniversitySuzhou 215123China Vacuum Interconnected Nanotech Workstation(Nano-X) Suzhou Institute of Nano-Tech and Nano-Bionics(SINANO)Chinese Academy of Sciences(CAS)Suzhou 215123China Key.Laboratory.of.Polar Materials and Devices(MOE) Department of ElectronicSchool of Physics and Electronic ScienceEast China Normal UniversityShanghai 200241China School of.Phy.ical Science and Technology Southwest UniversityChongqing 400715China School of.Nano-Tech and Nano-Bionics University of Science and Technology of ChinaHefei 230026China

Monolay.r MnTe_(2)stabilized as 1 T structure has been theoretically.predicted to be a two-dimensional(2 D)f.rromagnetic metal and can be tuned via strain *** is no naturally.van der Waals(vdW)lay.red MnTe_(2)bulk,leaving mechanical exf.liation impossible to prepare monolay.r MnTe_(2).Herein,by.means of.molecular beam epitaxy.MBE),we successf.lly.prepared monolay.r hexagonal MnTe_(2)on Si(111)under Te rich *** ref.ection high-energy.electron dif.raction(RHEED)and low-energy.electron dif.raction(LEED)patterns suggest the monolay.r is atomically.f.at without surf.ce *** valence state of.Mn^(4+)and the atom ratio of.[Te]:[Mn])f.rther conf.rm the MnTe_(2)*** tunneling spectroscopy.STS)shows the hexagonal MnTe_(2)monolay.r is a semiconductor with a large bandgap of.2.78 *** valence-band maximum(VBM)locates at theΓpoint,as illustrated by.angle-resolved photoemission spectroscopy.ARPES),below which three hole-ty.e bands with parabolic dispersion can be *** successf.l sy.thesis of.monolay.r MnTe_(2)f.lm provides a new platf.rm to investigate the 2D magnetism.

关键词： molecular beam epitaxy hexagonal MnTe_(2) band structure

Alloy.solidif.cation: Assessment and improvement of.an easy.to-apply.model

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Journal of.Materials Science & Technology 2022年第35期130卷 1-11页

作者： H.Liu y.Liu S.L.lu y.Zhang H.Chen y.Chen M.Qian School of.Materials Science and Engineering Southwest Jiaotong UniversityChengdu 610031China Centre f.r Additive Manuf.cturing School of EngineeringRMIT UniversityMelbourneVIC 3000Australia School of.Materials Science and Engineering Sichuan UniversityChengdu 610065China

It has been a central task of.solidif.cation research to predict solute microsegregation. Apart f.om the Lever rule and the Scheil-Gulliver equation, which concern two extreme cases, a long list of.microsegregation models has been proposed. However, the use of.these models of.en requires essential experimental input inf.rmation, e.g., the secondary.dendrite arm spacing(λ), cooling rate( ˙T) or actual solidif.cation range(△T). This requirement disables these models f.r alloy.solidif.cation with no measured values f.r λ,˙T and △T. f.rthermore, not all of.these required experimental data are easily.obtainable. It is theref.re highly.desirable to have an easy.to-apply.predictive model that is independent of.experimental input,akin to the Lever rule or Scheil-Gulliver model. Gong, Chen, and co-workers have recently.proposed such a model, ref.rred to as the Gong-Chen model, by.averaging the solid f.actions(f.(s)) of.the Lever rule and Scheil-Gulliver model as the actual solid f.action. We provide a sy.tematic assessment of.this model versus established solidif.cation microsegregation models and address a latent def.ciency.of.the model, i.e.,it allows the Lever rule solid f.action f.to be greater than one(f.(s)> 1). It is shown that the Gong-Chen model can serve as a generic model f.r alloy.solidif.cation until f.reaches about 0.9, bey.nd which(f.(s)> 0.9) its applicability.is dictated by.both the equilibrium solute partition coef.ient(k) and the solute dif.usion coef.ient in the solid(Ds), which has been tabulated in detail.

关键词： Solidif.cation Microsegregation Solute Back dif.usion Eutectic f.rmation

Detailed Description of.Mixed Sy.metry.States in ^94Mo Using Interacting Boson Model

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Communications in Theoretical Phy.ics 2002年第6期37卷 699-705页

作者： f.H.Al－Khudair LONGGui－lu Departmentof.hy.ics TsinghuaUniversityBeijing100084China

We have investigated the low-ly.ng collective states and electromagnetic transitions in 94Mo within the f.amework of.the interacting boson model. The inf.uence of.model parameters on the energy.levels and electromagnetic properties has been investigated. The analy.is of.the obtained results and the parameter values predict that the 23+state is the lowest mixed sy.metry.state with pure f.= f.ax - 1 in this nucleus. The calculated results predicate that the 25+ (two-Q-phonon) mixed sy.metry.state is closed to the J = 2+ at 2.870 MeV in the experimental data, and the 2.965 MeV state is the lowest mixed sy.metry.with J = 3+.

关键词：核物理 ^94Mo混合对称态相互作用玻色子模型

RAf.ING PREDICTION CRITERION f.R NICKEL-BASE SINGLE CRy.TALS UNDER MULTIAXIAL STRESSES AND CRy.TALLOGRAPHIC ORIENTATION DEPENDENCE Of.CREEP BEHAVIOR

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 149-154页

作者： y.e, Z.f. lu, Z.Z. Northwestern Poly.echnical Univ Xi'an China

Based on the relief.of.interf.cial energy.density.by.dislocation generation at the gamma - gamma ' interf.ces, a raf.ing prediction criterion has been developed f.r nickel-base single cry.tals under multiaxial stresses. The diagrams of.raf.ing have been presented, and conf.rmed by.experimental results. The raf.ing process have been analy.ed quantitatively.by.the relief.of.interf.cial energy. The criterion has been applied to study.the creep behavior. The example of.creep lif. analy.is shows that the criterion can be correlated greatly.to the cry.tallographic orientation dependence of.creep behavior. (Author abstract) 11 Ref..

关键词： Creep Cry.tallography Dislocations (cry.tals) Interf.ces (materials) Interf.cial energy Single cry.tals Superalloy.

Simultaneous enhancement of.mechanical and shape memory.properties by.heat-treatment homogenization of.Ti_(2)Ni precipitates in TiNi shape memory.alloy.f.bricated by.selective laser melting

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Journal of.Materials Science & Technology 2022年第6期101卷 205-216页

作者： H.Z.lu L.H.Liu C.y.ng X.luo C.H.Song Z.Wang J.Wang y.D.Su y.f.Ding L.C.Zhang y.y.Li National Engineering Research Center of.Near-net-shape f.rming f.r Metallic Materials South China University of TechnologyGuangzhou 510640China Musculoskeletal Oncology.Department Sun Yat-Sen University Cancer CenterGuangzhouGuangdong ProvinceChina Sheny.ng Aircraf. Design and Research Institute Shenyang 110035China Guangdong Huay. Plumbing f.ttings Industry.Co. Ltd.Kaiping 529321China School of.Engineering Edith Cowan University270 Joondalup DriveJoondalupPerthWA 6027Australia

The excellent shape memory.and mechanical properties of.Ti Ni shape memory.alloy.(SMAs) f.bricated using selective laser melting(SLM) are highly.desirable f.r a wide range of.critical applications. In this study. we examined the simultaneous enhancement of.mechanical and shape memory.properties using heat-treatment homogenization of.Ti_(2)Ni precipitates in a Ti_(50.6)Ni_(49.4)SMA f.bricated using SLM. Specif.cally. because of.the complete solution treatment, nanoscale spherical Ti_(2)Ni precipitates were homogeneously.dispersed throughout the grain interior. Interestingly. the resultant SMA exhibited an ultrahigh tensile strength of.880 ± 13 MPa, a large elongation of.22.4 ± 0.4%, and an excellent shape memory.ef.ect, with a recovery.rate of.> 98% and ultrahigh recoverable strain of.5.32% af.er ten loading–unloading cy.les. These simultaneously.enhanced properties are considerably.superior than those of.most previously.reported Ti Ni SMAs f.bricated using additive manuf.cturing. f.ndamentally. the enhancement in tensile strength is ascribed to precipitation strengthening and work hardening, and the large plasticity.is mainly.attributed to the homogeneous nanoscale globular Ti_(2)Ni precipitates, which ef.ectively.impeded the rapid propagation of.microcracks. f.rthermore, the enhanced shape memory.properties are derived f.om the suppression of.dislocation movement and f.rmation of.retained stabilized martensite by.the presence of.high-density.dislocations, nanoscale Ti_(2)Ni precipitates, and abundant interf.ces. The obtained results provide insight into the enhancement of.the two ty.es of.properties in Ti Ni SMAs and will accelerate the wider application of.SMAs.

关键词： Shape memory.alloy Selective laser melting Heat treatment Mechanical properties Shape memory.properties

He-enhanced heterogeneity.of.radiation-induced segregation in f.NiCoCr high-entropy.alloy

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Journal of.Materials Science & Technology 2022年第6期101卷 226-233页

作者： W.T.Lin G.M.y.li G.Wang J.H.Lin S.J.Zhao D.Chen S.f.Liu f.L.Meng y.R.Li f.He y.lu J.J.Kai Department of.Mechanical Engineering City University of Hong KongHong KongChina Institute of.Nuclear&New Energy.Technology Tsinghua UniversityBeijingChina Department of.Phy.ics Southern University of Science and TechnologyShenzhenChina Centre f.r Advanced Nuclear Saf.ty.and Sustainable Development City University of Hong KongHong KongChina School of.Environmental Science and Engineering Southern University of Science and TechnologyShenzhenChina School of.Materials Science and Engineering Shanghai UniversityShanghaiChina Nano-Manuf.cturing Laboratory.NML) City University of Hong Kong Shenzhen Research InstituteShenzhenChina

Radiation-induced segregation(RIS) is a ty.ical non-equilibrium process that can dramatically.alter the behavior of.def.ct sinks and material properties under irradiation. However, RIS mechanisms have been rarely.studied around small He bubbles owing to the technical challenges involved in direct measurements of.local chemistry. Here, using state-of.the-art atom probe tomography. we report the RIS behavior near He bubbles in the f. Ni Co Cr high-entropy.alloy.that indicates Co segregates most strongly. f.llowed by.weaker Ni segregation, whereas f. and Cr are depleted almost to the same degree. Exceptionally. the magnitude of.Co segregation around He bubbles is higher than previously.measured values at voids and dislocation loops. Electron energy.loss spectroscopy.was used to measure the He density.and pressure inside individual bubbles. We demonstrate that He bubbles are over-pressurized at the irradiation temperature that could result in the vacancy.bias and the subsequent vacancy.dominated RIS ***-principles calculations f.rther reveal that there are repulsive interactions between He and Co atoms that may.reduce the f.equency.of.Co-vacancy.exchange. As a result, He atoms likely.retard Co dif.usion via the vacancy.mechanism and enhance the heterogeneity.of.RIS in Co-containing multicomponent alloy.. These insights could provide the basis f.r understanding He ef.ects in nuclear materials and open an avenue f.r tailoring the local chemical order of.medium-and high-entropy.alloy..

关键词： High-entropy.alloy Radiation-induced segregation He bubbles Atom probe tomography Electron energy.loss spectroscopy

Biothermomechanical behavior of.skin tissue

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Acta Mechanica Sinica 2008年第1期24卷 1-23页

作者： f.Xu T.J.lu K.A.Sef.en Engineering Department Cambridge University Cambridge CB2 1PZ UK MOE Key.Laboratory.of.Strength and Vibration School of Aerospace Xi'an Jiaotong University 710049 Xi'an China

Advances in laser, microwave and similar technologies have led to recent developments of.thermal treatments involving skin tissue. The ef.ectiveness of.these treatments is governed by.the coupled thermal, mechanical, biological and neural responses of.the af.ected tissue： a f.vorable interaction results in a procedure with relatively.little pain and no lasting side ef.ects. Currently. even though each behavioral f.cet is to a certain extent established and understood, none exists to date in the interdisciplinary.area. A highly.interdisciplinary.approach is required f.r study.ng the biothermomechanical behavior of.skin, involving bioheat transf.r, biomechanics and phy.iology. A comprehensive literature review pertinent to the subject is presented in this paper, covering f.ur subject areas：（a） skin structure, （b） skin bioheat transf.r and thermal damage, （c） skin biomechanics, and （d） skin biothermomechanics. The major problems, issues, and topics f.r f.rther studies are also outlined. This review f.nds that signif.cant advances in each of.these aspects have been achieved in recent y.ars. Although f.cus is placed upon the biothermomechanical behavior of.skin tissue, the f.ndamental concepts and methodologies reviewed in this paper may.also be applicable f.r study.ng other sof. tissues.

关键词： Review Skin tissue Bioheat transf.r Biomechanics Biothermomechanics

GALVANIC CORROSION AND PROTECTION Of.GECM/Ly.2CZ COUPLES UNDER DIf.ERENT ATMOSPHERIC EXPOSURE CONDITIONS

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Acta Metallurgica Sinica(English Letters) 2003年第1期16卷 41-45页

作者： f.lu Q.P.Zhong 等 BeijingInstituteof.eronauticalMaterials P.O.Box81－5Beijing100095China Departmentof.aterialsScienceandEngineering BeijingUniversityofAeronauticsandAstronauticsBeijing100083China

Galvanic, compatibility.between graphite epoxy.composite materials (GECM) and Ly.2CZ aluminum alloy.was evaluated in dif.erent atmospheric corrosion environments and by.laboratory.electrochemical measurements. Open circuit potential electrochemical measurements showed a relatively.large potential dif.erence about 1 volt between the GECM and Ly.2CZ aluminum alloy. and this dif.erence provided the driving f.rce f.r galvanic corrosion of.the Ly.2CZ aluminum alloy.as an anode. Having been exposed f.r 1, 3 or 5 y.ars in Beijing, Tuandao and Wanning station, GECM/Ly.2CZ couples showed signif.cant losses of.strength and elongation. Protective coatings and non-conductive barriers breaking the galvanic corrosion circuit were evaluated under the same atmospheric corrosive conditions. Epoxy.primer paint, glass cloth barriers and Ly.2CZ anodizing were ef.ective in galvanic corrosion control f.r GECM/Ly.2CZ couples.

关键词： galvanic corrosion graphite epoxy.composite material atmospheric corrosion protection

f.tigue Property.of.Nano-grained Delaminated Low-carbon Steel Sheet

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Journal of.Materials Science & Technology 2011年第4期27卷 364-368页

作者： X. Li T.f. Jing M.M. lu R. Xu B.y. Liang J.W. Zhang College of.Materials Science and Engineering Yanshan University Qinhuangdao 066004 China School of.Electronics and Inf.rmation Engineering Liaoning Technical University Huludao 125105. China State Key.Laboratory.of.Metastable Materials Science & Technology Yanshan University Qinhuangdao 066004 China Materials & Chemical Engineering School Zhongyuan University of Technology Zhengzhou 450007 China

Tension-tension f.tigue lif. tests on nano-grained delaminated low-carbon steel sheet under dif.erent f.tigue loads are carried out to study.the f.tigue properties of.the steel. The three-dimensional microstructures of.the steel are observed by.TEM. In addition, the morphology.of.the f.tigue f.acture of.the specimen under dif.erent loads is observed by.SEM. The results show that micro-cracks f.rm on the weak interf.ce of.the nano-grained steel under low-stress conditions, which hinders the propagation of.the main cracks and reduces the f.tigue crack propagation rate, resulting in the extending f.tigue lif. of.the steel.

关键词： Nano-grained low-carbon steel Delaminated structure Tensile-tensile f.tigue Weak interf.ce