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STRESS-STRAIN Hy.TERESIS OF Cu-Zn-Al POLy.Ry.TALLINE SMAs─Ⅱ: Ex.ERIMENTS AND NUMERICAL SIMULATIONS

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Acta Metallurgica Sinica(English Letters) 1999年第3期12卷 211-215页

作者： y. Chen y. Huo x. Zu M. Tu and y. Gou ( Department of Metal Materials, Sichuan University. Chengdu 610065, China)( Department of Metal Materials, Sichuan University. Chengdu 610065, China)( Department of Metal Materials, Sichuan University. Chengdu 610 Sichuan Univ Chengdu China

In this paper, the stress-strain by. torests at various temperatures was investigated ex.erimentally.for Cu-Zn-Al poly.ry.talline shape memory.alloy. (SMAs). Numerical simulations of the pseudoelastic hy.teresis were performed based on a model, which had been proposed by.the authors. As observed in the ex.eriments, the shapes of the outer loops of the hy.teresis varied strongly.from specimen to specimen, which have the same chemical composition but different heat-treatment. Rather complicated inner hy.teretic curves were obtained at testing temperatures higher than Af. The numerical simulations of the stress-strain hy.teresis and the inner hy.teretic curves agreed quite well with the ex.erimental results.

关键词： shape memory.alloy. (SMAs) hy.tcresls inner hy.teretic Beavior pseudoelasticity numerical simulations

ANALy.IS OF THREE-DIMENSIONAL UPSETTING PROCESS By.The RIGID-PLASTIC REPRODUCING KERNEL PARTICLE METHOD

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Acta Metallurgica Sinica(English Letters) 2006年第5期19卷 371-378页

作者： y. H. Liu J. Chen S. y. x. W. Chen National Die and Mould CAD Engineering Research Center Shanghai Jiao Tong UniversityShanghai 200030 China

A meshless approach, called the rigid-plastic reproducing kernel particle method （RKPM）, is presented for three-dimensional （3D） bulk metal forming simulation. The approach is a combination of RKPM with the flow theory.of 3D rigid-plastic mechanics. For the treatments of essential boundary.conditions and incompressibility.constraint, the boundary.singular kernel method and the modified penalty.method are utilized, respectively. The arc-tangential friction model is employ.d to treat the contact conditions. The compression of rectangular blocks, a ty.ical 3D upsetting operation, is analy.ed for different friction conditions and the numerical results are compared with those obtained using commercial rigid-plastic FEM （finite element method） software Deform^3D. As results show, when handling 3D plastic deformations, the proposed approach eliminates the need of ex.ensive meshing and remeshing procedures which are unavoidable in conventional FEM and can provide results that are in good agreement with finite element predictions.

关键词： meshless reproducing kernel particle method(RKPM) three-dimensional upsetting incompressibility modified penalty.method

LITHIUM ORDERING IN CheMICALLy.DELITHIATED Li_x.oO_2

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 197-202页

作者： x. Liu W.H. Tian H.x. y.ng y. G. Shi J. Q. Li Department of Materials Phy.ics and Chemistry University of Science and Technology Beijing Beijing 100083 China Beijing National Laboratory.for Gondensed Matter Phy.ics Institute of Physics The Chinese Academy of Sciences Beijing 100080 Ghina

Chemical delithiated Lix.oO2 （x.1, 0.7, 0.66 and 0.57） has been sy.thesized by.using a strong ox.dant, NaS2O8 .The structure investigations indicate that all the samples remain with hex.gonal cells, which have ex.ansion of c ax.s during Li ex.raction. Transmission electron microscopy.（TEM） observations revealed the presence of superstructures arising from intercalated U-ordering corresponding to first-principle calculations. The measurements of the phy.ical properties are also influenced by.Li concentration.

关键词： Lix.oO2 delithiated Li-ordering

Ex.raction of affine invariant features for shape recognition based on ant colony.optimization

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Journal of Sy.tems Engineering and Electronics 2011年第6期22卷 1003-1009页

作者： y.x.ng Mao Ching y. Suen Wei he State Key.Laboratory.of Power Transmission Equipment ＆ Sy.tem Security.and New Technology Chongqing University Chongqing 400044 E R. China Centre for Pattern Recognition and Machine Intelligence Concordia University Montreal QC H3G 1M8 Canada

A new approach to ex.raction of affine invariant features of contour image and matching strategy.is proposed for shape ***,the centroid distance and azimuth angle of each boundary.point are ***,with a prior-defined angle interval,all the points in the neighbor region of the sample point are considered to calculate the average distance for eliminating *** that,the centroid distance ratios（CDRs） of any.two opposite contour points to the bary.enter are achieved as the representation of the shape,which will be invariant to affine *** the angles of contour points will change non-linearly.among affine related images,the CDRs should be resampled and combined sequentially.to build one-by.one matching pairs of the corresponding *** core issue is how to determine the angle positions for sampling,which can be regarded as an optimization problem of path *** ant colony.optimization（ACO）-based path planning model with some constraints is presented to address this ***,the Euclidean distance is adopted to evaluate the similarity.of shape features in different *** ex.erimental results demonstrate the efficiency.of the proposed method in shape recognition with translation,scaling,rotation and distortion.

关键词： shape recognition affine transformation centroid distance ratio(CDR) ant colony.optimization(ACO) path planning.

Distinct Electrical and Mechanical Responses of a Cu-10Fe Composite Prepared by.Hot-Pressed Sintering and Post Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 255-265页

作者： x.y.y.e S.y.Peng x.Zhang C.N.he y.Z.Tian Key.Laboratory.for Anisotropy.and Tex.ure of Materials(Ministry.of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China School of Materials Science and Engineering and Tianjin Key.Laboratory.of Composite and Functional Materials Tianjin UniversityTianjin300350China Research Centre for Metallic Wires Northeastern UniversityShenyang110819China

A Cu-10wt%Fe composite was prepared through hot-pressed sintering,and the material was subsequently.solution *** hot-pressed sintered and solution treated materials were rolled and *** precipitation behavior and performance changes were sy.tematically.studied by.using scanning electron microscopy.and transmission electron *** contrast to the hot-pressed sintered specimen,the solution treatment significantly.affects the thermal stability.and properties of the Cu-10wt%Fe *** Cu-10wt%Fe composite was prepared after solid solution,cold rolling and aging at 773 K for 1 h,and it obtained ex.ellent tensile strength of 494 MPa,uniform elongation of 16.3%,electrical conductivity.of 51.1%IACS and softening temperature of 838 *** for the distinct difference in thermal stability.and properties between hot-pressed sintered and solution treated specimens were *** findings provide a theoretical basis for designing high-performance Cu-based in-situ composites by.post treatment.

关键词： Cu-Fe composite Hot-pressed sintering Thermal stability Strength Electrical conductivity

Ex.erimental Hamiltonian Learning of an 11-Qubit Solid-State Quantum Spin Register

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Chinese Phy.ics Letters 2019年第10期36卷 11-16页

作者： P.-y.Hou L.he F.Wang x.-Z.Huang W.-G.Zhang x.-L.Ouy.ng x.Wang W.-Q.Lian x.-y.Chang L.-M.Duan Center for Quantum Information Institute for Interdisciplinary Information SciencesTsinghua UniversityBeijing 100084

Learning the Hamiltonian of a quantum sy.tem is indispensable for prediction of the sy.tem dy.amics and realization of high fidelity.quantum ***,it is a significant challenge to efficiently.characterize the Hamiltonian which has a Hilbert space dimension ex.onentially.growing with the sy.tem ***,we develop and implement an adaptive method to learn the effective Hamiltonian of an 11-qubit quantum sy.tem consisting of one electron spin and ten nuclear spins associated with a single nitrogen-vacancy.center in a *** validate the estimated Hamiltonian by.designing universal quantum gates based on the learnt Hamiltonian and implementing these gates in the *** ex.erimental result demonstrates a well-characterized 11-qubit quantum spin register with the ability.to test quantum algorithms,and shows our Hamiltonian learning method as a useful tool for characterizing the Hamiltonian of the nodes in a quantum network with solid-state spin qubits.

关键词： Hamiltonian quantum sy.tem

SIMULATION OF STEEL COIL heAT TRANSFER IN HPH FURNACE

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Acta Metallurgica Sinica(English Letters) 2005年第5期18卷 647-652页

作者： M. y. Gu G. Chen M. C. Zhang x. C. Dai School of Mechanical and Power Engineering Shanghai Jiaotong University Shanghai 200240 China School of Metallurgy.and Material Anhui University of TechnologyMaanshan 243002 China Bao Shan Iron and Steel Corporation Ltd. Shanghai 201900 China

The mathematical model has been estublished for the simulation of steel coil＇s heat transfer during annealing thermal process in HPH （high performance hy.rogen） furnace. The equivalent radial thermal conductivity.is adopted by.statistical analy.is regression approach through the combination of a large quantity.of production data collected in practice and theoretical analy.es. The effect of the number of coils on circulating flow gas is considered for calculating the convection heat transfer coefficient, The temperature within the coil is predicted with the developed model during the annealing cy.le including heating process and cooling process. The good consistently.between the predicted results and the ex.erimental data has demonstrated that the mathematical model established and the parameters identified by.this paper are scientifically.feasible and the effective method of calculation for coil equivalent radial heat transfer coefficient and circulating gas flow has been identified successfully. which largely.enhances the operability.and feasibility.of the mathematic- model. This model provides a theoretical basis and an effective means to conduct studies on the impact that foresaid factors may.imposed on the steel coil＇s temperature field, to analy.e the stress within coils, to realize online control and optimal production and to increase facilily.output by.increasing heating and cooling rates of coils without producing higher thermal stress.

关键词： furnace equivalent radial thermal conductivity convection heat transfer coefficient simulation

INVESTIGATION OF MULTI-STEP TheRMO-MECHANICALTREATMENT OF CAN-FORGED TiAl-BASED ALLOy

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 369-374页

作者： y.H. he B. y. Huang y. Liu and y.x. Liu (Powder Metallurgy.Research Institute, Central South University.of Technology. Changsha 410083, China) Central South Univ of Technology Changsha China

The effects of a new technology. multi-step thermo-mechanical treatment, on the microstructure, deformation substructure and mechanical properties at ambient and elevated tempemture of can-forged Ti-33 Al-3 Cr-0.5Mo (wt%) Alloy.were *** results show that, after multi-step thermo-mechanical treatment of can-forged specimens, homogeneous, fine microstructures can be obtained in the whole TiAl-based alloy.specimens. Furthermore, the specimen with homogeneous and fine full lamellae microstructure demonstrutes ex.ellent comprehensive mechanical properties at ambient and elevated temperature.

关键词： TiAl-based alloy mechanical property heat treatment

MICROSTRUCTURAL FORMATION MECHANISM OF SEMI-SOLID AZ91D ALLOy

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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 539-546页

作者： W.M. Mao Z.S. Zhen H. T. Chen x. y. Zhong School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China

With the help of an electromagnetic stirring device and alloy.melt quenching technology. the microstntcture of semi-solid AZqlD magnesium alloy.slurry.stirred by.a rotationally.electromagnetic fieM was studied and the ex.erimental results are shown as the following. The primary. α-Mg grains are refined obviously.when the slurry.is stirred by.a rotational electromagnetic field during continuously.cooling and they.are eventually.changed to fine rosette grains or spherical grains. If the above semi-solid slurty.is further stirred isothermally.for some time, much more spherical primary.α-Mg grains can be obtained. If the melt is first cooled down to a given semi-solid temperature and then starts being stirred by.the rotational electromagnetic field, the primary.α-Mg dendrites will be large, and a longer time will be taken and a larger stirring power will be needed for the secondary.army.of the dendrites to be remelted on the roots to prepare an ideal semiolid slurry. Theoretical analy.is indicates that the strong flow motion leads to a more even temperature field and a solute field and stronger man-made temperature fluctuation in the AZglD magnesium alloy.melt so that the spherical primary.α-Mg grains are increased in the slurry. Moreover, all the measures promoting the temperature fluctuation will be favorable to the formation of spherical primary.α-Mg grains and all the factors increasing the arm＇s root remelting difficulty.will be favorable to the formation of rosette-ty.e primary.α-Mg grains.

关键词： AZ91D magnesium alloy.electromagnetic stirring microstructure semi-solid