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STUDy OF THE EXCHANGE BIAS FIELD OF NiFe/FeMn BILAyERS

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Acta Metallurgica Sinica(English Letters) 2002年第2期15卷 238-242页

作者： M.H. Li1’2), G.H. yu1). F. w. Zhu1) and w.y. lai2) 1)Department of Material Physics, University of Science and Technology Beijing, Beijing 100083, China 2)State Key Laboratory for Magnetism. Institute of Physics, The Chinese Academy of Sciences, Beijing Department of Material Physics University of Science and Technology BeijingBeijing 100083China State Key Laboratory for Magnetism Institute of PhysicsThe Chinese Academy of SciencesBeijing 100080China Department of Material Physics University of Science and Technology BeijingBeijing 100083China State Key Laboratory for Magnetism Institute of PhysicsThe Chinese Academy of SciencesBeijing 100080China

The exchange bias field of NiFe/FeMn films with Ta/ Cu buffer was proved tobe lower than that of the films with Ta buffer. The crystallographic texture, surface roughness andelements distribution were examined in these two sets of samples, and there is no apparentdifference for the texture and roughness. However, the segregation of Cu atoms above NiFe surface inthe multilayer of Ta/Cu/NiFe has been observed by using the angle-resolved X-ray photoelectronspectroscopy (XPS). The decrease of the exchange bias field for NiFe/FeMn films with Ta/ Cu bufferlayers is mainly caused by the Cu atoms segregation at the interface between NiFe and FeMn.

关键词： NiFe/FeMn exchange bias field texture surface roughness surfacesegregation

Structural Modal Parameter Recognition and Related Damage Identification Methods under Environmental Excitations: A Review

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Structural Durability & Health Monitoring 2025年第1期19卷 25-54页

作者： Chao Zhang Shang-Xi lai Hua-Ping wang School of Civil Engineering and Mechanics Lanzhou UniversityLanzhou730000China Key Laboratory of Special Functional Materials and Structural Design Ministry of EducationLanzhou UniversityLanzhou730000China

Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the ***,it is particularly signiﬁcant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientiﬁc basis for structural damage identiﬁcation and dynamic model modiﬁ*** view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and brieﬂy describes how to identify structural damages based on the derived modal *** paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),brieﬂy describes damage identiﬁcation methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artiﬁcial intelligence(AI)methods in the direction of modal parameter recognition and damage identiﬁcation is further *** on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identiﬁcation methods are given to provide scientiﬁc references for the optimized design and functional upgrading of SHM systems.

关键词： Structural health monitoring data information modal parameters damage identiﬁcation AI method

Liver surgery and transplantation in China: Progress and Challenges

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Frontiers of Medicine 2007年第1期1卷 1-5页

作者： LAU w.y.lai E C H Department of Surgery The Chinese University of Hong KongPrince of Wales HospitalShatinNew TerritoriesHong Kong SAR.China

From the limited but available information,we traced the history of developments of liver surgery and transplantation in *** surgery first started in the late 1950s in China,and it soon flourished mainly because of the great demand in liver surgery and the emergence of a number of giants in liver *** recognized and honoured the important contributions of these Chinese pioneers in portal hypertension,recurrent pyogenic cholangitis,hepatocellular carcinoma and liver transplantation.

关键词： liver surgery transplantation

COUPLED SIMULATION OF 3D ELECTRO-MAGNETO-FLOw FIELD IN HALL-HEROULT CELLS USING FINITE ELEMENT METHOD

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Acta Metallurgica Sinica(English Letters) 2006年第2期19卷 105-116页

作者： J. Li w. Liu y.Q. lai Q.y. Li y.X. Liu School of Metallurgy Science and Engineering Central South University Changsha 410083 China Chemistry Department Guangxi Normal University Guilin 531400 China

Two full 3D steady mathematical models are developed by finite element method （FEM） to calcalate coupled physics fields. the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.

关键词： coupled simulation electromagnetic field flow field aluminum reduction cell finite element analysis

Structures and formation mechanisms of dislocation-induced precipitates in relation to the age-hardening responses of Al-Mg-Si alloys

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Journal of Materials Science & Technology 2020年第6期41卷 127-138页

作者： y.X.lai w.Fan M.J.yin C.L.wu J.H.Chen Center for High-Resolution Electron Microscopy College of Materials Science&EngineeringHunan UniversityChangsha 410082China Electron Microscopy Center Shenzhen UniversityShenzhen 518060China

In the slightly deformed Al-Mg-Si alloys,dislocation-induced precipitates are frequently observed,and they usually line up,forming sophisticated precipitation *** atomic-resolution electron microscopy in association with hardness measurements,we systematically investigated these precipitates in relation to the age-hardening responses of the *** study reveals that the majority of dislocation-induced complex precipitates are actually short-range ordered while long-range disordered polycrystalline precipitates and multiphase composite precipitates,including polycrystalline U2 precipitates,B’/U2,B’-2/U2,B’/B’-2/U2 and’/U2 composite *** is suggested that the formation of these complex precipitates is mainly owing to a high nucleation rate and rapid growth of different precipitate phases parallel to the associated dislocation *** dislocation-induced precipitates consume more Mg than Si from the matrix and have a high formation kinetics,they will have different impacts on the matrix precipitation in different types of Al-Mg-Si *** results further demonstrate that for the"normally-β"-hardened"alloy,their formation leads to a coarser precipitate microstructure in the matrix,whereas for the"normally-β’-hardened"alloy,their formation reverses the precipitation pathw.y.in the matrix,resulting in a reduced age-hardening potential of the former alloy and an improved age-hardening potential of the latter alloy.

关键词： Al-Mg-Si alloys Precipitation Dislocation Age-hardening Electron microscopy

Effect of drainage on CO_2, CH_4, and N_2O fluxes from aquaculture ponds during winter in a subtropical estuary of China

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Journal of Environmental Sciences 2018年第3期30卷 72-82页

作者： Ping yang Derrick y.F lai Jia F.Huang Chuan Tong School of Geographical Sciences Fujian Normal University Key Laboratory of Humid Sub-tropical Eco-geographical Process of Ministry of Education of China Fujian Normal University Department of Geography and Resource Management and Centre for Environmental Policy and Resource ManagementThe Chinese University of Hong Kong

Aquaculture ponds are dominant features of the landscape in the coastal zone of ***,aquaculture ponds are drained during the non-culture period in ***,the effects of such drainage on the production and flux of greenhouse gases（GHGs）from aquaculture ponds are largely *** the present study,field-based research was performed to compare the GHG fluxes between one drained pond（DP,with a water depth of 0.05 m）and one undrained pond（UDP,with a water depth of 1.16 m）during one winter in the Min River estuary of southeast *** the entire study period,the mean CO2flux in the DP was（0.75±0.12）mmol/（m^2·hr）,which was significantly higher than that in the UDP of（-0.49±0.09）mmol/（m^2·hr）（p0.01）.This indicates that drainage drastically transforms aquaculture ponds from a net sink to a net source of CO2in *** CH4and N2O emissions were significantly higher in the DP compared to those in the UDP（CH4=（0.66±0.31）vs.（0.07±0.06）mmol/（m^2·hr）and N2O=（19.54±2.08）vs.（0.01±0.04）μmol/（m^2·hr））（p〈0.01）,suggesting that drainage would also significantly enhance CH4and N2O *** in environmental variables（including sediment temperature,p H,salinity,redox status,and water depth）contributed significantly to the enhanced GHG emissions following pond ***,analysis of the sustained-flux global warming and cooling potentials indicated that the combined global warming potentials of the GHG fluxes were significantly higher in the DP than in the UDP（p〈0.01）,with values of739.18 and 26.46 mg CO2-eq/（m^2·hr）,*** findings suggested that drainage of aquaculture ponds can increase the emissions of potent GHGs from the coastal zone of China to the atmosphere during winter,further aggravating the problem of global warming.

关键词： Aquaculture pond Drainage management Greenhouse gas flux Global warming Min River estuary

EFFECT OF Cu-Ni CONTENT ON THE CORROSION RESISTANCE OF(Cu-Ni)/(10NiO-90NiFe_2O_4)CERMET INERT ANODE FOR ALUMINUM ELECTROLySIS

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Acta Metallurgica Sinica(English Letters) 2008年第1期21卷 72-78页

作者： Z.L. Tian y.Q. lai J. Li y.X. Liu School of Metallurgical Science and Engineering Central South University Changsha 410083 China

（Cu-Ni）/（10NiO-90NiFe204） cermet inert anodes containing metal Cu-Ni0, 5, 10, 15 and 20 wt pct were prepared and their corrosion resistance to Na3AlF6-Al2O3 melts was investigated. The results indicate that the content of metal Cu-Ni has little effect on the steady-state concentration of Ni in the electrolyte and the values could not be used to effectively differentiate their corrosion resistance. The steady-state concentration of Fe decreases from 304×10^-6 to 168×10^-6 and that of Cu increases from 21×10^-6 to 71×10^-6 with the content of metal Cu-Ni increasing from 0 to 20 wt pct. Post-examination shows that metallic phase Cu-Ni is corroded preferentially during electrolysis and many pores are left at the anode surface. Considering the corrosion resistance and electrical conductivity, the cermet containing metal Cu-Ni 5 wt pct should be selected and studied further.

关键词： Aluminum electrolysis Inert anode NiFe2O4 based cermet Corrosion resistance

EFFECT OF STRUCTURAL PARAMETERS ON THE THERMAL STRESS OF A NiFe_(2)O_(4)-BASED CERMET INERT ANODE IN ALUMINUM ELECTROLySIS

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Acta Metallurgica Sinica(English Letters) 2007年第2期20卷 139-147页

作者： J. Li Z.G. wang y.Q. lai y.y. wu S.L. ye School of Metallurgy Science and Engineering Central South University Changsha 410083 China

Inert anode has been a hot issue in the aluminum industry for many decades. with the help of FEA （finite element analysis） software ANSyS, a model was developed to simulate the thermal stress distribution working condition of an inert anode. To reduce its thermal stress, the effect of some parameters on the thermal stress distribution was investigated, including the anode height, the anode radius, the hole depth, the hole radius, and the radius of inner chamfer and outer chamfer. The results showed that in the actual working condition of an inert anode, there existed a large axial tensile stress near the tangent interface between the anode and bath, which was the major cause of anode breaking. Increasing the anode height and reducing the hole depth properly seemed to be beneficial for the stress distribution. with the increase of anode radius, the stress distribution became better first and then deteriorated, the reasonable value was between 0.045 to 0.06m. The hole radius had a significant effect on the stress and a smaller radius would reduce the thermal stress. The effect of the radius of the inner chamfer and the outer chamfer was less than other parameters.

关键词： inert anode thermal stress structural parameter aluminum electrolysis

Numerical Study of an Annular Gas Turbine Combustor with Dump Diffuser

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Journal of Thermal Science 1999年第1期8卷 59-64页

作者： J.X.Zhao y.B.lai DepartmentofPowerEngineering NanjingUniversityofAeronauticsandAstronautics210016NanjingChina Depar

A general numerical method is presented for calculating steady three-dimensional and two-phase turbulent reactive flows with a nonstaggered body-fitted coordinate system in an annular gas turbine combustor with the dump diffuser. The modified two-equation model and the EDC turbulent combustion model are used for the gas phase. The liquid phase equations are solved in a Lagrangian frame of reference by PSIC algorithm. The effect of different velocity profiles at the entry of the prediffuser on combustor flow characteristics is calculated.

关键词： numerical simulation annular combustor dump diffuser 3D body-fitted coordinate two phase combustion.