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Experimental and numerical study of the effect of pulsatile flow on wall displacement oscillation in a flexible lateral aneurysm model

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Acta Mechanica sinica 2019年第5期35卷 1120-1129页

作者： l.z.Mu x.y.li q.z.Chi s.q.yang P.D.zhang C.j.ji y.he g.gao school of Energy and Power Engineering Dalian University of TechnologyDalian 116024China school of biomedical Engineering Capital Medical UniversityBeijing 100069China The First Affiliated Hospital of University of science and Technology of China Hefei 230036China

This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental *** maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm *** is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance *** results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.

关键词： lateral aneurysm In vitro experiment Pulsatile flow Wall displacement oscillation Fluid-structure interaction simulation

suppression of auto-resonant stimulated brillouin scattering in supersonic flowing plasmas by different forms of incident lasers

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Chinese Physics b 2020年第9期29卷 364-368页

作者： s s ban q Wang z j liu C y zheng x T he heDPs Center for Applied Physics and TechnologySchool of PhysicsPeking UniversityBeijing 100871China Institute of Applied Physics and Computational Mathematics Beijing 100094China

In supersonic flowing plasmas,the auto-resonant behavior of ion acoustic waves driven by stimulated brillouin backscattering is self-consistently investigated.A nature of absolute instability appears in the evolution of the stimulated brillouin *** adopting certain form of incident lights combined by two perpendicular linear polarization lasers or polarization rotation lasers,the absolute instability is suppressed *** suppression of auto-resonant stimulated brillouin scattering is verified with the fully kinetic Vlasov code.

关键词： inertial confinement fusion laser plasma interaction stimulated brillouin scattering fully kinetic simulation

IMPROVEMENT OF CARbIDE MORPHOlOgy ANDMECHANICAl PROPERTIEs OF Cr12MoV sTEEls

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Acta Metallurgica sinica(English letters) 2000年第5期13卷 1053-1058页

作者： Cui, x.H. jiang, q.C. Wang, s.q. he, z.M. sch. of Mat. sci. and Eng. Jilin Univ. of Technol. Changchun 130025 China

Compared with conventional cast Cr12MoV steel and forged Cr12MoV steels, carbide morphology and properties of modified cast Cr12MoV steels were investigated by performing hardness test, impact test, fracture toughness test, fatigue crack propagation test, metallographic examination and quantitatively metallographic analysis. The results indicate that the carbide morphology in modified cast steel is characterized by uniformly-distributed granular carbide, which is different from that of conventional cast steel, but similar to that of forged steel. the impact toughness of modified cast steel is distinctly increased to 12.75 j/cm2 from 6.8 j/cm2 in the conventional cast steel with networked carbide, because of carbide granulation. Furthermore, The fracture toughness and fatigue-crack-propagation threshold of modified cast steel are not only higher than that of the conventional cast steel, but also higher than that of the forged steels.

关键词： Alloys Carbides Mechanical properties Morphology

Analysis of extreme ultraviolet spectral profiles of laser-produced Cr plasmas

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Chinese Physics b 2019年第7期28卷 319-323页

作者： l Wu M g su q Min s q Cao s q he D x sun C z Dong Key laboratory of Atomic and Molecular Physics & Functional Material of gansu Province College of Physics and Electronic EngineeringNorthwest Normal University

Radiation from laser-produced plasmas was examined as a potential wavelength calibration source for spectrographs in the extreme ultraviolet(EUV) ***, the EUV emission of chromium(Cr) plasmas was acquired via spatiotemporally resolved emission *** the aid of Cowan and flexible atomic code(FAC) structure calculations,and a comparative analysis with the simulated spectra, emission peaks in the 6.5–15.0 nm range were identified as 3 p–4 d, 5 d and 3 p–4 s transition lines from Cr5+–Cr10+ions.A normalized boltzmann distribution among the excited states and a steady-state collisional-radiative model were assumed for the spectral simulations, and used to estimate the electron temperature and density in the *** results indicate that several relatively isolated emission lines of highly charged ions would be useful for EUV wavelength calibration.

关键词： laser-produced plasmas highly charged ions extreme ultraviolet wavelength calibration

Micro-sized and Nano-sized Fe_3O_4 Particles as Anode Materials for lithium-ion batteries

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journal of Materials science & Technology 2011年第1期27卷 41-45页

作者： y.x.Chen l.H.he P.j.shang q.l.Tang z.q.liu H.b.liu l.P.zhou College of Materials science and Engineering Hunan UniversityChangsha 410082China shenyang National laboratory for Materials science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

Micro-sized（1030.3±178.4 nm） and nano-sized（50.4±8.0 nm） Fe3O4 particles have been fabricated through hydrogen thermal reduction of α-Fe2O3 particles synthesized by means of a hydrothermal *** morphology and microstructure of the micro-sized and the nano-sized Fe3O4 particles were characterized by x-ray diffraction,field-emission gun scanning electron microscopy,transmission electron microscopy and highresolution electron *** micro-sized Fe3O4 particles exhibit porous structure,while the nano-sized Fe3O4 particles are solid *** electrochemical performance was also *** nano-sized solid Fe3O4 particles exhibit gradual capacity fading with initial discharge capacity of 1083.1 mAhg-1 and reversible capacity retention of 32.6% over 50 ***,the micro-sized porous Fe3O4 particles display very stable capacity-cycling behavior,with initial discharge capacity of 887.5 mAhg-1 and charge capacity of 684.4 mAhg-1 at the 50th ***,77.1% of the reversible capacity can be maintained over 50 *** micro-sized porous Fe3O4 particles with facile synthesis,good cycling performance and high capacity retention are promising candidate as anode materials for high energy-density lithium-ion batteries.

关键词： lithium-ion battery Fe3O4 Porous structure Anode materials

Accident of large-scale Wind Turbines Disconnecting from Power grid and Its Protection

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电力系统自动化 2012年第8期36卷 105-109页

作者： Dong, x.z. shi, s.x. Wang, b. bak, D.j. Cao, R.b. Ren, l. lan, l. he, s.E. state Key lab. of Power systems Department of Electrical Engineering Tsinghua University Beijing 100084 China Wind Power Technology Center Gansu Electric Power Corporation Lanzhou 730050 China

There were many accidents of large-scale wind turbines disconnecting from power grid in *** singlephase-to-ground fault cannot be correctly detected,single-phase-to-ground fault evolved to phase-to-phase ***-to-phase fault was isolated slowly,thus leading to low *** wind turbines without enough low voltage ride-through capacity had to be disconnected from the *** some wind turbines being disconnected from the grid,overvoltage caused by reactive power surplus made more wind turbines disconnect from the *** on the accident analysis,this paper presents solutions to above problems,including travelling waves based single-phase-to-ground protection,adaptive low voltage protection,integrated protection and control,and high impedance fault *** solutions lay foundations in theory and technology to prevent large-scale wind turbines disconnecting from the operating power grid.

关键词：大型风力发电机组低电压保护电网事故断开单相接地故障风力涡轮机故障检测切断电源

Unusually high corrosion resistance in Mo_(x)CrNiCo medium entropy alloy enhanced by acidity in aqueous solution

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journal of Materials science & Technology 2023年第8期139卷 59-68页

作者： s.shuang g.j.lyu D.Chung x.z.Wang x.gao H.H.Mao W.P.li q.F.he b.s.guo x.y.zhong y.j.Wang y.yang Department of Mechanical Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongChina state Key laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China school of Engineering science University of Chinese Academy of SciencesBeijing 101408China state Key laboratory of solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China Unit of structures Department of Materials Science and EngineeringKTHStockholm SE-10044Sweden Thermo-Calc software Råsundav.18SolnaSE-16767Sweden Department of Materials science and Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongChina Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou 510632China Department of Advanced Design and system Engineering College of EngineeringCity University of Hong KongKowloon TongKowloonHong KongChina

High corrosion resistance of alloys is essential for their structural applications;however,most alloys suffer from degradation of their corrosion resistance with the increasing acidity of their ***,we developed a series of medium-entropy alloys(MEAs)in this work,which ex-hibit high strength,superior fracture toughness and ultra-high corrosion resistance,outperforming the variety of corrosion resistant alloys hitherto *** interestingly,our MEAs exhibit an unusual anti-corrosion behavior and their corrosion resistance increases with acidity in Cl−containing *** extensive thermodynamic calculations,density functional theory(DFT)simulations and experi-ments,we reveal that the unusual anti-corrosion behavior of our MEAs can be attributed to their surface chemical complexity,which facilitates the physio-chemical-absorption of H_(2)O and O_(2)and thus the rapid formation of metastable medium entropy passive films that contain the lowest amount of defects,as compared to the passive films on conventional alloys reported in the literature.

关键词： Corrosion Passivation Alloy design Multi-principal element alloys Medium-entropy alloys

Rational design of chemically complex metallic glasses by hybrid modeling guided machine learning

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npj Computational Materials 2021年第1期7卷 1242-1251页

作者： z.q.zhou q.F.he x.D.liu q.Wang j.H.luan C.T.liu y.yang Department of Mechanical Engineering College of EngineeringCity University of Hong KongKowloonHong KongChina College of Mechatronics and Control Engineering Shenzhen UniversityShenzhenChina laboratory for structures Institute of Materials ScienceShanghai UniversityShanghaiChina Department of Materials science and Engineering College of EngineeringCity University of Hong KongKowloonHong KongChina Department of Advanced Design and system Engineering College of EngineeringCity University of Hong KongChina

The compositional design of metallic glasses(Mgs)is a long-standing issue in materials science and ***,traditional experimental approaches based on empirical rules are time consuming with a low *** this work,we successfully developed a hybrid machine learning(Ml)model to address this fundamental issue based on a database containing~5000 different compositions of metallic glasses(either bulk or ribbon)reported since *** the prior works relying on empirical parameters for featurization of data,we designed modeling guided data descriptors in line with the recent theoretical models on amorphization in chemically complex alloys for the development of the hybrid classification-regression Ml *** hybrid Ml modeling was validated both numerically and *** importantly,it enabled the discovery of Mgs(either bulk or ribbon)through the Ml-aided deep search of a multitude of quaternary to scenery alloy *** computational framework herein established is expected to accelerate the design of Mg compositions and expand their applications by probing the complex and multi-dimensional compositional space that has never been explored before.

关键词： alloy glasses metallic

Microstructure and mechanical properties of double-side friction stir welded 6082Al ultra-thick plates

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journal of Materials science & Technology 2020年第6期41卷 105-116页

作者： C.yang j.F.zhang g.N.Ma l.H.Wu x.M.zhang g.z.he P.xue D.R.Ni b.l.xiao K.s.Wang z.y.Ma shenyang National laboratory for Materials science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China school of Materials science and Engineering University of Science and Technology of ChinaShenyang 110016China CRRC Changchun Railway Vehicles Co. Ltd.Changchun 130062China school of Metallurgical Engineering Xi’an University of Architecture and TechnologyXi’an 710055China

In the present work,80 mm thick 6082Al alloy plates were successfully double-side welded by friction stir welding(FsW).The relationship between the microstructures and mechanical properties was built for the double-side FsW butt joint with more attention paid to the local characteristic *** was shown that a phenomenon of microstructural inhomogeneity existed in the nugget zone(Nz)through the thickness *** grain size presented an obvious gradient distribution from the top to the bottom for each single-pass weld,and the microhardness values decreased from both surfaces to the middle of the *** lowest hardness zone(lHz)exhibited a"hyperbolical"-shaped distribution extending to the middle of the *** tensile properties were obtained in the three sliced specimens of the FsW joint,and the joint coefficient reached about 70%which achieved the same level as the conventional FsW Al alloy *** element modeling proved that the"hyperbolical"-shaped heat affected zone(HAz)was beneficial to resisting the strain concentration in the middle layer specimen which helped to increase the tensile *** on the analysis of the hardness contour map,tensile property and microstructural evolution of the joints,an Isothermal softening layer(Isl)model was proposed and established,which may have a helpful guidance for the optimization on the FsW of ultra-thick Al alloy plates.

关键词： Ultra-thick aluminum alloy plates Double-side friction stir welding Finite element model Microstructural inhomogeneity Mechanical properties