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Acta Mechanica Sinica 2015年第3期31卷 392-405页

作者： D.Yang q.c.he School of Mechanical Engineering Southwest Jiaotong University Université Paris-Est Laboratoire Modélisation et Simulation Multi Echelle UMR 8208 CNRS

This work aims at determining the overall response of a two-phase elastoplastic composite to isotropic loading. The composite under investigation consists of elastic particles embedded in an elastic perfectly plastic matrix governed by the Mohr-coulomb yield criterion and a non-associated plastic flow rule. The composite sphere assemblage model is adopted, and closed-form estimates are derived for the effective elastoplastic properties of the composite either under tensile or compressive isotropic loading. In the case when elastic particles reduce to voids, the composite in question degenerates into a porous elastoplastic material. The results obtained in the present work are of interest, in particular, for soil mechanics.

关键词： composite Porous medium. Elastoplasticity Mohr-coulomb yield criterion Non-associated flow rule Homogenization

Mathematical modeling and numerical computation of the effective interfacial conditions for Stokes flow on an arbitrarily rough solid surface

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Applied Mathematics and Mechanics(English Edition) 2021年第5期42卷 721-746页

作者： A.T.TRAN H.LE qUANG q.c.he D.H.NGUYEN Research and Application center for Technology in civil Engineering University of Transport and CommunicationsHanoi 10000Vietnam Laboratoire Modelisation et Simulation Multi-Echelle Unite Mixte de Recherche 8208Centre National de la Recherche ScientifiqueUniversite Gustave EiffelMarne-la-Vallee F-77454France School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China

The present work is concerned with a two-dimensional(2D)Stokes flow through a channel bounded by two parallel solid *** distance between the walls may be arbitrary,and the surface of one of the walls can be arbitrarily *** main objective of this work consists in homogenizing the heterogeneous interface between the rough wall and fluid so as to obtain an equivalent smooth slippery fluid/solid interface characterized by an effective slip *** solve the corresponding problem,two efficient numerical approaches are elaborated on the basis of the method of fundamental solution(MFS)and the boundary element methods(BEMs).They are applied to different cases where the fluid/solid interface is periodically or randomly *** results obtained by the proposed two methods are compared with those given by the finite element method and some relevant ones reported in the *** comparison shows that the two proposed methods are particularly efficient and accurate.

关键词： effective slip length method of fundamental solution(MFS) boundary element method(BEM) Stokeslet micro-channel fluid/solid interface

Allelopathic effect of Acorus tatarinowii upon algae

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Journal of Environmental Sciences 2001年第4期13卷 481-484页

作者： he, c.-q. Wang, c.-k. Dept. of Environmental Science/Eng. Shanghai University Shanghai 200072 China

Besides competing with algae for light and mineral nutrients (i. e. N, P, etc.), the root system of Acorus tatarinowii excretes some chemical substances, which injure and eliminate alga cells, to inhibit the growth of the algae. When the algae cells were treated in 'A. tatarinowii water', some of the chlorophyll a were destroyed and the photosynthetic rate of algae decreased markedly and the ability of alga cells to deoxidize triphenyltetrazolium chloride (TTc) reduced greatly. Then alga cells turned from bright red to bluish green under fluorescence microscope. These showed that the allelopathic effects of A. tatarinowii on algae were obvious and planting A. tatarinowii can control some green algae. The experiment on the extractions of the secretions of the root system showed that the inhibitory effect had a concentration effect. If the concentration of the root secretion was below 30 μl/disc, the inhibitory rate was negative; if it was over 45 μl/disc, the inhibitory rate was positive. This proved that the influence of the root secretion on the same acceptor was a kind of concentration effect. When the concentration of the root secretion was low, it promoted the growth of algae; when the concentration reached a definite threshold value, it restrained the growth of algae. In present case, the threshold value was between 30 μl/disc and 45 μl/disc.

关键词： Algae cells chlorophyll concentration (process) Deoxidants Photosynthesis

Precipitation on stacking faults in Mg–9.8wt%Sn alloy

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Journal of Materials Science & Technology 2020年第10期42卷 230-240页

作者： c.q.Liu c.he H.W.chen J.F.Nie International Joint Laboratory for Light Alloys(Ministry of Education) College of Materials Science and EngineeringChongqing UniversityChongqing400044China Department of Materials Science and Engineering Monash UniversityVictoria3800Australia Electron Microscopy center Chongqing UniversityChongqing400044PR China

In this work,we have systematically investigated precipitation ofβ’-Mg3Sn phase on intrinsic stacking faults I1 and I2 in a Mg-9.8 wt%Sn alloy using aberration-corrected scanning transmission electron *** observed I1 faults are generated by the dissociation of c+a perfect dislocations and bounded by Frank partial dislocations having a Shockley *** ofβ’on I1 involves a shear of 1/3α,similar to its formation directly from theα-Mg ***β’phase often nucleates at one end of an I1 fault due to the interaction between shear strain fields ofβ’and the Shockley component of the Frank partial at that end,and subsequently grows towards the other end of the *** theβ’reaches to the other end,the Shockley partial bounding the lengthening end of theβ’reacts with the Frank partial bounding the fault,generating an a perfect dislocation that can glide away from the precipitate and the *** observed I2 faults are generated by the dissociation of a perfect dislocations and bounded by Shockley *** ofβ’on I2 does not need a shear of 1/3α,since the pre-existing I2 fault already provides an ABcA four-layer structure ofβ’.Thickening of theβ’that has already formed on the I2 involves the successive occurrence of three crystallographically equivalent shears of 1/3αon every second(0002)αplane of theα-Mg *** this thickening mechanism is similar to that of theβ’formed directly from theα-Mg matrix,an a perfect dislocation will be produced when theβ’is thickened to eight layers,and it can again glide away from the precipitate and the fault.

关键词： heterogeneous precipitation HAADF-STEM Shockley partial dislocation Frank partial dislocation Dislocation reaction

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

EFFEcT OF MODIFIcATION ON cARBIDE GRANULATION AND ITS MEcHANISM

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Acta Metallurgica Sinica(English Letters) 1999年第2期12卷 167-172页

作者： Wang, S.q. Jiang, q.c. cui, X.H. he, Z.M. Jilin Univ of Technology Changchun China

By the modification, network carbide is disconnected at 1100 degree c through uneven dissolution at higher energy places in carbide, where there is twin or lattice distortion, and is granulated at 1130 degree c through element diffusion. The stability of M//7c//3 carbide is decreased because of the modification reducing the segregation of cr and Mo, thus the temperature, at which uneven dissolution of carbide commenced, is decreased. Also lattice distortion or defect such as twin in carbide is increased by the modification, which prompts widespread disconnections in carbide. In addition, the modification prompts element diffusion to accelerate the kinetics process of carbide granulation. (Edited author abstract) 6 Refs.

关键词： carbides chromium alloys Granulation Modification Morphology

Axisymmetric wetting of a liquid droplet on a stretched elastic membrane

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Applied Mathematics and Mechanics(English Edition) 2023年第6期44卷 997-1006页

作者： c.q.RU Department of Mechanical Engineering University of AlbertaEdmontonAB T6G 2G8Canada

Wetting of a liquid droplet on another liquid substrate is governed by the well-known Neumann *** present work aims to develop an explicit modified version of the Neumann equations for axisymmetric wetting of a liquid droplet on a highly stretched elastic membrane of non-zero bending *** explicit modified form of the Neumann equations is derived to determine the two contact angles,which is reduced to Young's equation for a liquid droplet on a rigid membrane or to the Neumann equations for a liquid droplet on another liquid *** implications of the modified Neumann equations are examined by comparison with some previous results reported in the recent literature,particularly considering the ranges of material and geometrical parameters of the liquid droplet-membrane system which have not been recently addressed in the literature.

关键词： Neumann equation Young's equation liquid droplet membrane pretension

Interfacial Instability of Two Bonded Elastic Bodies Driven by Interface or Bulk Residual Stress

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Acta Mechanica Solida Sinica 2023年第6期36卷 914-920页

作者： c.q.Ru Department of Mechanical Engineering University of AlbertaEdmonton T6G 2G8Canada

Inspired by recent research interest in the interface wrinkling of bonded materials in diverse areas of 3D printing,the present work studies the interfacial instability of two bonded elastic bodies driven by negative interfacial tension or compressible bulk residual *** interfacial instability modes decaying exponentially with distance from the interface,the present model is formulated for two bonded elastic half-spaces with a planar interface under plane *** explicit expression is given for the wavenumber of interfacial instability driven by negative interfacial tension,and a critical condition is derived for interfacial instability driven by compressive bulk residual *** derived results are validated with comparison to known results on surface instability of an elastic half-space,and the role of shear modulus ratio and Poisson’s ratios of two bonded elastic bodies in interfacial instability,an issue to be addressed in literature,is studied with specific reference to material parameters used in some areas of 3D printing.

关键词： Interfacial tension Surface tension Interfacial instability 3D printing Interface wrinkling

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

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