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Finite Element Prediction of the Thermal Conductivity of GNP/Al Composites

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Acta Metallurgica Sinica(English Letters) 2022年第5期35卷 825-838页

作者： X.S.Yang L.zhou K.Y.Liu z.Y.Liu Q.z.Wang b.L.Xiao z.Y.Ma School of Electromechanical and Automotive Engineering Yantai UniversityYantai264005China Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

A 3 D multi-scale finite element model was developed to predict the effective thermal conductivity of graphene nanoplatelet(GNP)/Al *** factors influencing the effective thermal conductivity of the GNP/Al composites were investigated,including the orientation,shape,aspect ratio,configuration and volume fraction of *** results show that GNPs shape has a little influence on the thermal conductivity of GNP/Al composites,and composites with elliptic GNPs have the highest thermal *** addition,with increasing the aspect ratio of GNPs,the thermal conductivity of GNP/Al composites increases and finally tends to be *** GNPs configuration strongly influences the thermal conductivity of GNP/Al composites,and the thermal conductivity of the composites with layered GNPs is the highest among the five *** effective thermal conductivity is sensitive to volume fraction of ***,when the volume fraction of layered GNPs reaches 1.54%,the thermal conductivity of GNP/Al composites is as high as 400 W/m *** findings of this study could provide a good theoretical basis for designing high thermal conductivity GNP/Al composites.

关键词： Multi-scale finite element model Thermal conductivity GNP/Al composites Shape Aspect ratio Configuration

澳门科学一号卫星对闪电诱发电子沉降现象的首次观测结果

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中国科学:地球科学 2025年第1期55卷 1-9页

作者：王庸平孙翌馨宗秋刚陆高鹏顾旭东胡泽骏李斌中国极地研究中心(中国极地研究所)自然资源部极地科学重点实验室上海200136 北京大学空间物理与应用技术研究所北京100871 澳门科技大学月球与行星科学国家重点实验室中国澳门999078 中国科学技术大学地球和空间科学学院合肥230026 武汉大学电子信息学院武汉430072

中能电子探测器(Medium-energy Electron Spectrometers,MES)是澳门科学一号卫星(Macao Science Satellite-1,MSS-1)上载荷的探测仪器,专门用于监测卫星轨道上的典型带电粒子辐射特征及其发生和发展过程,包括闪电诱发电子沉降现象(Light... 详细信息

中能电子探测器(Medium-energy Electron Spectrometers,MES)是澳门科学一号卫星(Macao Science Satellite-1,MSS-1)上载荷的探测仪器,专门用于监测卫星轨道上的典型带电粒子辐射特征及其发生和发展过程,包括闪电诱发电子沉降现象(Lightning-Induced Electron Precipitation,LEP).本文介绍了MSS-1卫星对LEP的首次观测结果.在初期3个月的运行中,MSS-1卫星共识别出47次LEP事件,全部位于1.5

关键词：闪电诱发电子沉降内辐射带高能电子澳门科学一号卫星(MSS-1)

Simulations of deformation and damage processes of SiCp/Al composites during tension

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Journal of Materials Science & Technology 2018年第4期34卷 627-634页

作者： J.F.zhang X.X.zhang Q.z.wang b.L.Xiao z.Y.Ma Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China

The deformation, damage and failure behaviors of 17 vol.% SiCp/2009AI composite were studied by micro- scopic finite element （FE） models based on a representative volume element （RVE） and a unit cell. The RVE having a 3D realistic microstructure was constructed via computational modeling technique, in which an interface phase with an average thickness of 50 nm was generated for assessing the effects of interracial properties. Modeling results showed that the RVE based FE model was more accurate than the unit cell based one. based on the RVE, the predicted stress-strain curve and the fracture morphology agreed well with the experimental results. Furthermore, lower interface strength resulted in lower flow stress and ductile damage of interface phase, thereby leading to decreased elongation. It was revealed that the stress concentration factor of SiC was -2.0： the average stress in SiC particles reached -1200 MPa, while that of the composite reached -600 MPa.

关键词： Metal matrix composites (MMCs) Fracture Finite element (FE) analysis Interfacial strength Tensile strength Representative volume element (RVE)

Exploring Variability in Sea Level at a Tide Gauge Station through Control Charts

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Journal of Environmental & Earth Sciences 2024年第1期6卷 11-18页

作者： H.bâkiİz Independent Scholar Boca Raton Florida33496USA

Monitoring temporal changes in sea level is important in assessing coastal *** level anomalies at a tide gauge station,if kinematically conceived,include systematic variations such as trend,acceleration,periodic oscillations,and random *** them,the non-stationary nature of the random sea level variations of known or unknown origin at coastal regions has been long recognized by the sea level *** study proposes the analyses of subgroups of random residual statistics of a rigorously formulated kinematic model solution of tide gauge variations using X-bar and S control *** approach is demonstrated using Key West,Florida tide gauge *** mean and standard errors of 5-year-long subgroups of the residuals revealed that sea level changes at this location have been progressively intensifying from 1913 to the *** oscillations in sea level at this locality may be attributed partly to the thermal expansion of seawater with increasing temperatures causing larger buoyancy-related sea level fluctuations as well as the intensification of atmospheric events including wind patterns and the impact of changes in inverted barometer effects that will alter coastal risk assessments for the future.

关键词： Climate change Sea level variance X-bar S control charts

Room-temperature ferroelectricity in A-site ordered Ruddlesden-Popper Li_(2)CaTa_(2)O_(7) ceramics

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Journal of Materiomics 2020年第3期6卷 593-599页

作者： b.H.zhang z.z.Hu b.H.Chen X.Q.Liu X.M.Chen Laboratory of Dielectric Materials School of Materials Science and EngineeringZhejiang UniversityNo.38 Zheda RoadHangzhou310027China

In the present work,the crystal structure,ferroelectric and dielectric properties of the dense single-phase Li_(2)CaTa_(2)O_(7) ceramics with A-site ordered double-layer Ruddlesden-Popper structures have been investigated by the experiments and first-principles calculations.A polar Pna21 phase was determined by the Rietveld refinement against the X-ray diffraction pattern at room temperature,and it was confirmed by its lowest calculated energy and rigid phonon *** ferroelectricity was found by observing the ferroelectric hysteresis loop at room temperature,and its remanent polarization was similar to the value calculated from the berry phase and born effective charge *** ferroelectricity is a nonconventional proper one since its polarization is induced from the displacement of oxygen anions instead of tantalum cations based on the individual atomic polarization.A first-order transition from an antiferroelectric to paraelectric phase around 900 K was found by the DSC and variable-temperature dielectric *** the present work,the room-temperature ferroelectricity is experimental confirmed in the present ceramics,inspiring the search for new ferroelectricity in the ceramics with A-site ordered Ruddlesden-Popper structures.

关键词： Ferroelectricity A-site ordered ruddlesden-popper Dielectric response First-principles calculation

Magnetic and Transport Properties of Mn_(0.98)Cr_(0.02)Te Epitaxial Films Grown on Al_2O_3 Substrates

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Journal of Materials Science & Technology 2014年第2期30卷 103-106页

作者： z.H.Wang D.Y.Geng J.Li Y.b.Li z.D.zhang Shenyang National Laboratory for Materials Science Institute of Metal Researchand International Centre for Materials PhysicsChinese Academy of Sciences Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of Sciences

The epitaxial Mno0.98Cr0.02Te films on single crystal Al2O3 （0001） substrates were prepared by pulsed laser deposition. The X-ray diffraction and scanning electron microscopy results showed that the good continuous epitaxial film was obtained with substrate temperature of 500 ℃. When the substrate temperature reached 700 ℃, the film was island growth and the manganese oxides phase appeared. The temperature dependence of both the magnetization and electrical resistance showed a sharp rise at around 60 K due to the magnetoelastic coupling. The temperature dependence of the electrical resistance of Mno0.98Cr0.02Te provided evidence for a transition from the metallic to semiconducting state at 305 K due to the spin disorder scattering with a large contribution from the influence of magnon drag.

关键词： Magnetic properties Mno0.98Cr0.02Te films X-ray diffraction Epitaxial film

Structural & Magnetic Characterizations of NiLizn Nanoferrites Synthesized by Co-precipitation Method

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Journal of Materials Science & Technology 2011年第11期27卷 991-995页

作者： D.N. Rohadiana z.A.z. Jamal S.b. Jamaludin M.F. bari J. Adnan Sustainable Engineering Research Cluster Universiti Malaysia Perlis School of Microelectronic Engineering Universiti Malaysia Perlis

Synthesis of ***（0.5-x）Fe204 nanoparticles with x=0, 0.1, 0.2, 0.3, 0.4 and 0.5 were realized via coprecipitation method. X-ray diffraction （XRD） and vibrating sample magnetometer （VSM） measurements were performed on the samples to determine the characteristics of the crystal structures and the magnetic properties of the samples, respectively. The spinel phase structures of the samples were confirmed by XRD analysis. Patterns of decreased lattice parameter and increased crystallite size values were observed by increasing the Li concentration at longer synthesis reaction periods. Similarly, for the magnetic properties, both the saturation magnetization （Ms） and coercivity （Hc） were found to vary with increasing patterns at higher Li doping levels and longer synthesis reaction periods. The results and mechanisms concerned were discussed.

关键词： Lithium nickel zinc ferrite Co-precipitation Crystal structure Magnetic properties

Mechanisms of eutectic lamellar destabilization upon rapid solidification of an undercooled Ag-39.9 at.% Cu eutectic alloy

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Journal of Materials Science & Technology 2020年第24期59卷 173-179页

作者： H.Dong Y.z.Chen z.R.zhang G.b.Shan W.X.zhang F.Liu State Key Lab.of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China Yangtze River Delta Research Institute of NPU Taicang 215400China

The eutectic Ag-Cu alloys exhibiting fine Ag-Cu lamellar eutectic structure formed upon rapid solidification have great potentials being used in various engineering ***,the desired fine primary lamellar eutectic structure(PLES)is usually replaced by a coarse anomalous eutectic structure(AES)when the undercooling prior to solidification exceeds a certain *** forming mechanism of AES in the undercooled eutectic Ag-Cu alloy has been a controversial *** this work,the undercooled Ag-39.9 at.% Cu eutectic alloy is solidified under different cooling conditions by using techniques of melt fluxing and copper mold *** results show that the coupled eutectic growth of this alloy undergoes a transition from a slow eutectic-cellular growth(ECG)to a rapid eutectic-dendritic growth(EDG)above a undercooling of 72 K,accompanying with an abrupt change of the distribution and amount of AES in as-solidified *** kinds of primary lamellar eutectic structures are formed by ECG and EDG during recalescence,*** destabilization of PLES that causes the formation of AES is ascribed to two different mechanisms based on the microstructural examination and theoretical *** 72 K,the destabilization of PLES formed by slow ECG is caused by the mechanism of"termination migration"driven by interfacial *** above 72 K,the destabilization of PLES formed by rapid EDG is attributed to the unstable perturbation of interface driven by interfacial energy and solute supersaturation.

关键词： Ag-Cu alloys Rapid solidification Undercooling Eutectics Destabilization

EFFECT OF The DEFECT STATES DENSITY ON OPTICAL bAND GAP OF CdIn_(2)O_(4)THIN FILM

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 403-410页

作者： H.S.San z.G.Wu b.Li b.X.Feng KeyLaboratoryforMagnetismandMagneticMaterialofMinistryofEducation LanzhouUniversityLanzhou730000China ShanghaiInstituteofTechnicalPhysics TheChineseAcademyofSciencesShanghai200083China

Transparent conducting oxides CdIn2O4 thin films were prepared by radio-frequenc y reactive sputtering from a Cd-In alloy target in Ar+O2 atmosphere. by transmis sion spectrum and Hall measurement for different samples prepared at different s ubstrate temperatures, it could be found that the carrier concentration would in crease with the decrease of substrate temperature, but absorption edge showed an abrupt variation from a blue shift to a red shift. Theoretically, the paper for mulated the effect of high-density point defects on band structures; it embodied the formation of band tailing, burstein-Moss shift and band-gap narrowing. The density of holes will influence the magnitude of optical band gap and transmitta nce of light. Since extrapolation method does not fit degenerate semiconductor m aterials, a more accurate method of obtaining optical band gap is curve fitting. In addition, ionized impurities scattering is the main damping mechanism of the free electrons in CdIn2O4 films, the density of ionized impurities induced by a ltering substrate temperature will affect the carriers mobility.

关键词： sputtering CdIn2O4 thin film electrical property optical property