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Acta Mechanica Sinica 2019年第6期35卷 1241-1256页

作者： z.y.liu T.L.Jiang L.Wang H.L.Dai Department of Mechanics Huazhong University of Science and TechnologyWuhan 430074China Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment Wuhan 430074China

Pipe-in-pipe(PIP)structures are widely used in offshore oil and gas pipelines to settle thermal insulation issues.A PIP structure system usually consists of two concentric pipes and one softer layer for thermal insulation *** total response of the system is related to the dynamics of both pipes and the interactions between these two concentric *** the current work,a theoretical model for flow-induced vibrations of a PIP structure system is proposed and analyzed in the presence of an internal axial flow and an external cross *** interactions between the two pipes are modeled by a linear distributed damper,a linear distributed spring and a nonlinear distributed spring along the pipe *** unsteady hydrodynamic forces due to cross flow are modeled by two distributed van der Pol wake *** nonlinear partial differential equations for the two pipes and the wake are further discretized by the aid of Galerkin’s technique,resulting in a set of ordinary differential *** ordinary differential equations are further numeri cally solved by using a fourth-order Runge-Kutta integration *** portraits,bifurcation diagrams,an Argand diagram and oscillation shape diagrams are plotted,showing the existence of a lock-in phenomenon and figure-of-eight *** PIP system subjected to cross flow displays some interesting dynamical behaviors different from that of a single-pipe structure.

关键词： Cantilevered PIP structure Theoretical model Flow-induced vibration Cross flow Internal flow

Anisotropy of the Wear Behavior for Carbon Nanotube-Reinforced 6061Al Composites

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Acta Metallurgica Sinica(English Letters) 2023年第5期36卷 814-826页

作者： X.N.Li J.F.zhang W.H.Xue K.Ma P.y.Li z.y.liu B.L.Xiao D.R.Ni Q.z.Wang D.Wang z.y.Ma School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

Carbon nanotube(CNT)-reinforced 6061Al(CNT/6061Al)composites with directionally aligned CNT were fabricated,and their wear behavior was *** results indicate that the wear properties of CNT/6061Al composites exhibited a significant anisotropy.A certain CNT concentrations(1 wt%and 2 wt%)could effectively improve the wear resistance of CNT/6061Al composites along the CNT circumferential and CNT radial directions for the load transfer,grain refinement and self-lubrication effect of *** Brass{011}and{112}textures inhibited the load transfer effect of CNT along the CNT radial direction,resulting in a better wear resistance along CNT circumferential direction than CNT radial *** the CNT axial direction,the weak deformability of composites caused by the intensifyingfiber texture was the main reasons for the poor wear resistance of CNT/6061Al composites with increasing CNT concentration.

关键词： Carbon nanotube Metal matrix composite Wear Anisotropy

Microscopic stresses in carbon nanotube reinforced aluminum matrix composites determined by in-situ neutron diffraction

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Journal of Materials Science & Technology 2020年第19期54卷 58-68页

作者： X.X.zhang J.F.zhang z.y.liu W.M.Gan M.Hofmann H.Andrä B.L.Xiao z.y.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China German Engineering Materials Science Centre at MLz Helmholtz-Zentrum GeesthachtD-85747 GarchingGermany Heinz Maier-Leibnitz zentrum(MLz) Technische Universität MünchenD-85747 GarchingGermany Fraunhofer Institute for Industrial Mathematics Fraunhofer-Platz 1Kaiserslautern 67663Germany

One of the most desired strengthening mechanisms in the carbon nanotube reinforced aluminum matrix composites(CNT/Al)composites is the load transfer strengthening mechanism(LTSM).However,a fundamental issue concerning the LTSM is that quantitative measurements of load partitioning in these composites during loading are very *** this study,in-situ neutron diffraction study on the tensile deformation of the 3 vol.%CNT/2009 Al composite and the unreinforced 2009 Al alloy was ***{311}and{220}diffraction elastic constants(DECs)of the 2009 Al alloy were *** those DECs the average stress in the 2009 Al matrix of the composite was *** the average stress in the CNTs was separated by using the stress equilibrium *** homogenization models were also applied to explain the stress evolution in each *** results agree with experimental *** the present case,the average stress in the CNTs reaches 1630 MPa at the yield strength of the composite based on linear regression of the measured data,which leads to an increment of yield strength by about 37 *** the result of this work,an approach to quantify load partitioning in the CNTs is developed for the CNT/Al composites,which can be applied to optimize the mechanical properties of the composites.

关键词： Carbon nanotubes Aluminum matrix composites In-situ neutron diffraction Load partitioning

MODELING OF STRAIN-INDUCED PRECIPITATION KINETICS IN Nb MICROALLOyED STEELS

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Acta Metallurgica Sinica(English Letters) 2006年第5期19卷 385-390页

作者： X. G. zhou z. y. liu D. Wu z. Li C.M. Li State Key Lab. of Rolling and Automation Northeastern University Shenyang 110004 China Baoshan Iron ＆ Steel Co. Ltd. Shanghai 201900 China Engineering ＆ Research Incorporation Limited WISDRI （Wuhan Iron ＆ Steel Design and

On the basis of the thermodynamic calculation of precipitation and considering the effect of strain on the precipitation behavior and chemical composition （Si and Mn）, the kinetics of precipitation from austenite has been investigated for different temperatures and strains. Nucleation theory and the solubility product of niobium, carbon, and nitrogen in austenite have been used to derive equations for the start time of precipitation as a function of temperature and composition. The value of n in Avrami equation was determined using the available experimental data from the published reports, which indicated that n is a constant independent of temperature and the end time of precipitation is a function of n and the start time of precipitation. The values of the start time and end time of precipitation predicted by the new model are compared with the experimental values and a good agreement was obtained between both.

关键词： strain-induced precipitation start time of precipitation end time ofprecipitation precipitation kinetics

NUMERICAL SIMULATION OF MOLTEN POOL AND CONTROL STRATEGy OF KISS POINT IN A TWIN-ROLL STRIP CASTING PROCESS

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Acta Metallurgica Sinica(English Letters) 2008年第6期21卷 459-468页

作者： G.M. Cao C.G. Li z. y. liu D. Wu G.D. Wang X.H. liu State Key Laboratory of Rolling ＆ Automation Northeastern University Shenyang 110004 China

Coupled turbulent flow, temperature fields of the twin-roll casting strip process were simulated by three-dimensional finite element method. Based on the heat balance calculation and using inverse methods between the simulations and real experiments, the relational models among casting speed, location, and coefficient of heat transfer between molten metal and rolls in different regions are given. In the simulation, the calculated surface temperatures are in good agreement with the measured values. An on-line model of kiss point is derived by simulations and the geometry of molten pool, corresponding control strategy is also proposed.

关键词： Twin-roll strip casting Coupled temperature and flow field Numerical simulation Kiss point Control strategy

MODELING OF STATIC RECRySTALLIzATION KINETICS OF Nb-BEARING STEELS

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 271-278页

作者： L.Q. Ma z.y. liu S.H. Jiao X.Q. yuan D. Wu The State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang 110004 China Institute of Research and Development Baosteel Co. Ltd Shanghai 201900 China

By using isothermal double hit compression tests and applying the 2% offset method, a new model was developed to predict the microstructural evolution of Nb-bearing steels at temperatures above and below the start temperature of strain-induced precipitation （Tp）. The Tp was developed as a function of true strain, initial austenite grain size and the Nb content. The activation energy of static recrystallization （Qrex） was expressed as a function of the content of different alloy elements. It was found that Nb played the most important role in increasing the value of Qrex, The microstructural observations and measurements confirmed the validity of the model developed in the present investigation.

关键词： Nb-bearing steel static recrystallization Tp (start temperature of strain-induced precipitation) activation energy

Construction of 2D/2D Ti_(3)C_(2)T_(x)MXene/CdS heterojunction with photothermal effect for efficient photocatalytic hydrogen production

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Journal of Materials Science & Technology 2024年第4期171卷 1-9页

作者： T.y.Huang z.yang S.y.yang z.H.Dai y.J.liu J.H.Liao G.y.zhong z.J.Xie y.P.Fang S.S.zhang Key Laboratory for Biobased Materials and Energy of Ministry of Education Guangdong Laboratory for Lingnan Modern AgricultureCollege of Materials and EnergySouth China Agricultural UniversityGuangzhou 510643China School of Physics and Optoelectronics South China University of TechnologyGuangzhou 510640China School of Chemical Engineering and Energy Technology Guangdong Provincial Key Laboratory of Distributed Energy SystemsDongguan University of TechnologyDongguan 523808China

The insensitivity of semiconductors to visible and infrared light is a key constraint on the utilization of light energy in photocatalytic *** photocatalysts with full-spectrum absorption through surface engineering is an effective approach to fully harnessing light energy in semiconductor ***,a novel stable Ti_(3)C_(2)T_(x)MXene/CdS heterojunction catalyst is obtained by in-situ epitaxial growth of two-dimensional(2D)CdS nanosheets on 2D MXene interface via a solvothermal *** exceptional light absorption properties of MXene confer outstanding full-spectrum driven photocat-alytic hydrogen evolution capability upon the heterogeneous *** unique 2D/2D structure effectively mitigated the recombination of photogenerated carriers,enhancing the photocatalytic performance of the ***,the composite catalyst exhibits a significantly higher surface temperature of 80.4℃under visible light irradiation at an intensity of 0.1 W/cm^(2),which is 1.84 times higher than that of *** irradiation of visible and near infrared light,the composite catalyst with photothermal ef-fect demonstrates a remarkable hydrogen evolution rate of 65.4 mmol g^(-1)h^(-1),which is 7.2 times higher than that of CdS *** study introduces a novel approach for constructing full-spectrum absorption catalysts and expands the application of the photothermal effect in photocatalytic hydrogen evolution research.

关键词： Two-dimensional structure Heterostructure Photothermal effect Photocatalyst Hydrogen evolution

Rational design of AgGaS/znS/znS quantum dots with a near-unity photoluminescence quantum yield via double shelling scheme

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Journal of Materials Science & Technology 2024年第2期169卷 235-242页

作者： H.X.Lu H.liu z.z.Fu y.y.Chen H.Q.Dai z.Hu W.L.zhang R.Q.Guo Institute for Electric Light Sources School of Information Science and TechnologyFudan UniversityShanghai 200433China Institute of Future Lighting Academy for Engineering and TechnologyFudan UniversityShanghai 200433China yiwu Research Institute of Fudan University YiwuZhejiang 322000China zhongshan-Fudan Joint Innovation Center Zhongshan 528437China

In this study,a two-step method was used to synthesize highly luminescent AgGaS/znS/znS quantum dots(QDs).In the first step,an inner znS shell was formed via a one-pot method,which resulted in a smaller lattice mismatch between the AgGaS core and the outer znS shell,thereby facilitating the formation of a thick outer *** the two-step shelling process,the synthesized AgGaS/znS/znS QDs showed an excellent photoluminescence quantum yield(PLQy)of 96.4%with a peak wavelength of 508 nm,repre-senting the highest PLQy reported thus far for AgGaS ***,the effect of halogen ions in zn precursors on the shelling process was *** was proposed that the capacity of halogen ions to coordinate with the QDs influenced the balance between zn cation diffusion and znS shelling ***,the znS shelling reaction was dominant when znCl_(2)was employed,while zn cation diffusion was the dominant process under the I^(−)-rich *** work provides insights into the interfacial restructuring during the znS shelling and offers a clear map for the tailored synthesis of core/shell QDs.

关键词： AgGaS Quantum dots Photoluminescence Core/shell Alloyed core/shell interface

STUDy ON COMPOSITION, MICROSTRUCTURE AND HARDNESS OF DLC FILMS By VCAD

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 271-275页

作者： L.Chen z.y.liu D.C.zeng W.Q.Qiu z.H.yuan S.S.Lin H.J.Hou InstituteofMaterialsScience&Technology CollegeofMechanicalEngineeringSouthChinaUniversityofTechnologyGuangzhou510640China GuangzhouResearchInstituteofNon-FerrousMetals Guangzhou510651ChinaManuscriptreceived25November2002

DLC super-hard films have been deposited on the substrates of single crystalline Si, pure Ti and stainless steel 18-8 by a method of vacuum cathode arc deposition (VCAD). The composition, microstructure and micro-hardness of the films have been studied in this paper. The results indicate that hardness of the DLC films is different on the different substrates. Hardness of the films increases with decreasing in surface roughness of the films. The maximum value of micro-hardness belongs to the DLC films deposited under the hydrogen pressure of 0.35Pa and the negative bias of 100V.

关键词： DLC films vacuum cathode arc deposition micro-hardness

Single crystal growth, structural and transport properties of bad metal RhSb2

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Chinese Physics B 2020年第3期29卷 1-6页

作者： D S Wu y T Qian z y liu W Wu y J Li S H Na y T Shao P zheng G Li J G Cheng H M Weng J L Luo Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100190China Songshan Lake Materials Laboratory Dongguan 523808China

We have successfully grown an arsenopyrite marcasite type RhSb2 single crystal, and systematically investigated its crystal structure, electrical transport, magnetic susceptibility, heat capacity, and thermodynamic properties. We found that the temperature-dependent resistivity exhibits a bad metal behavior with a board peak around 200 K. The magnetic susceptibility of RhSb2 shows diamagnetism from 300 K to 2 K. The low-temperature specific heat shows a metallic behavior with a quite small electronic specific-heat coefficient. No phase transition is observed in both specific heat and magnetic susceptibility data. The Hall resistivity measurements show that the conduction carriers are dominated by electrons with ne = 8.62 × 10^(18) cm^(-3) at 2 K, and the electron carrier density increases rapidly above 200 K without change sign. Combining with ab-initio band structure calculations, we showed that the unusual peak around 200 K in resistivity is related to the distinct electronic structure of RhSb_2. In addition, a large thermopower S(T) about -140 μV/K is observed around 200 K, which might be useful for future thermoelectric applications.

关键词： single crystal growth ab-initio band calculations susceptibility heat capacity thermodynamic transport properties