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Microstructural Dependence of Damping Behaviour of Eutectoid Zn-Al Based Alloy (ZA27)──Discussion of "Damping Behaviour and Mechanism of Graphite Particulate Reinforced Metal Matrix Composites

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Journal of Materials Science & Technology 1999年第2期15卷 178-180页

作者： Zhu, y.h. Institute de Investigaciones en Materiales UNAM Mexico D.F. 04510 Apart.P.70-360 Mexico Dept. of Manufacturing Engineering Hong Kong Polytechnic University Hong Kong

Enantio-divergent C–h borylation with two different ligands from a single chiral source

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Science China Chemistry 2025年第01期 226-232页

作者： Rongrong du Senmiao Xu State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical Physics Chinese Academy of Sciences College of Material Chemistry and Chemical Engineering Key Laboratory of Organosilicon Chemistry and Material TechnologyMinistry of Education Hangzhou Normal University University of Chinese Academy of Sciences

Reported here is an iridium-catalyzed enantio-divergent C（sp3）–h borylation of α-gem-dimethyl groups of trifluoromethyl ketone-derived hydrazones to construct a series of acyclic all-carbon quaternary stereocenters with a high level of chiral induction. Two different chiral bidentate boryl ligands from a common chiral source not only can switch the enantioselectivity but also are complementary in terms of the substrate scope.

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MEChANICAL BEhAVIOR OF FCC CRySTAL SIMULATED By 3-D DISCRETE DISLOCATION DyNAMICS

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Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 94-102页

作者： y.yu X.X. Pan y.h. Rong School of Materials Science and Engineering Shanghai Jiaotong University Shanghai 200030 China Institute of Structural Mechanics China Academy of Engineering Physics Mianyang 621900 ChinaManuscript received 31 May 2007

To simulate the mechanical behavior of the FCC crystal with the lower Peierls stress, the stiff property and physical meaning of the differential equation group consisting of dislocation evolution and mechanical state was investigated based on the 3-D discrete dislocation dynamics; the results indicate that the differential equation group is serious stiff, namely the external stress changes more quickly than dislocation evolution. Using the established numerical algorithm, the mechanical behavior of FCC crystal was simulated with the dislocations located in the parallel slip planes, and the effect of strain rate on the dislocation configuration and mechanical behavior, and the sat- uration process of mobile dislocation were discussed. The simulation results indicate that the numerical algorithm can efficiently simulate the dislocation dipole and the low strain rate loading.

关键词： FCC crystal Mechanical behavior Dislocation dynamics Nu-merical simulation

ON ThE DyNAMIC ChARACTERISTICS OF MOULD-FILLING UNDER COUNTERGRAVITy

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Acta Metallurgica Sinica(English Letters) 1997年第5期10卷 409-414页

作者： Zeng, J.M. Gu, h. Zhou, y.h. Guangxi Univ Nanning China

In this paper, the mathematical models for mould-filling under countergravity are derived on the basis of the principle of momentum. Dynamic processes of mould-filling are observed on a perspex model by means of high speed photography. The results indicate that the mould-filling under countergravity can be described by the second order nonlinear differential equations characterized by damping oscillations. The velocity oscillations amplify as the pressuring speed increases if the pressure differential functions are of the same type. On the other hand, if the functions are of different type, then the velocity oscillations depend upon whether the functions progressively increase or decrease. Velocity oscillations can be diminished dramatically by increasing the local damping within the gating system.

关键词： casting mould-filling dynamics

2nd UMN-CAS Bilateral Seminar on PM2.5 science, health effects and control technologies, October 7-8, 2015 at 3M Innovation Center, Maplewood, MN, USA

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Particuology 2016年第4期14卷 141-142页

作者： David y.h. Pui Junji Cao University of Minnesota MN 55455 USA Institute of Earth Environment Chinese Academy of Sciences Xi'an China

The First UMN-CAS Bilateral Seminar was successfully.h.ld in Xi＇an, China, May 27-28,2014. A summary of the 1 st Bilateral Seminar was published in Particuology 16 （2014）, 227-229. The Second UMN-CAS Bilateral Semi... 详细信息

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COORELATION ANALySIS OF SURFACE PRESSURE FLUCTUATIONS ON ThREE EQUISPACED CyLINDERS

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Journal of hydrodynamics 2001年第2期13卷 55-62页

作者： Dong, L.y. Xu, y.h. huang, D.Q. Inst. of Appl. Math. and Mech. Shanghai Univ. Shanghai 200072 China

The fluctuating pressures on the surface of three circular cylinders in equispaced arrangement were measured simultaneously in the medium subcritical regime (Re=3×104). The distributions of their rms values and circumferential correlation were obtained in the spacing range from 1.25 to 6.0. The spatial correlation of pressures of two pressure taps on two different cylinders at the same azimuth was investigated as well. Owing to different flow patterns in various arrangements and spacing, these correlation curves of pressure show different distributions. The lift fluctuation can be estimated qualitatively from the circumferential coefficient curve with the knowledge of the rms pressure distribution. Some critical spacing for each arrangement were found that the flow regimes and the corresponding pressure correlation take a sudden change. Flow interference between cylinders in each arrangement was also discussed with various flow regimes.

关键词： Cylinders (shapes) Experiments Flow interactions Flow patterns Pressure distribution Pressure measurement

EVOLUTION OF MICROSTRUCTURE OF Sn-Ag-Cu LEAD-FREE FLIP ChIP SOLDER JOINTS duRING AGING PROCESS

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 301-306页

作者： y.h. Tian C.Q. Wang W.F. Zhou State Key Lab of Advanced Welding Production and Technology Harbin Institute of Technology Harbin 150001 China

Flip chip bonding has become a primary technology that has found application in the chip interconnection process in the electronic manufacturing industry in recent years. The solder joints of the flip chip bonding are small and consist of complicated microstructures such as Sn solution, eutectic mixture, and intermetallic compounds （IMCs）, whose mechanical performance is quite different from the original solder bulk. The evolution of microstructure of the flip chip solder joints under thermal aging was analyzed. The results show that with an increase in aging time, coarsening of solder bulk matrix and AuSn4 IMCs occurred within the solder. The IMCs that are formed at the bottom side of the flip chip bond were different from those on the top side during the aging process. （Cu, Ni, Au）0Sn5 were formed at the interfaces of both sides, and large complicated （Au,Ni, Cu）Sn4 IMCs appeared for some time near the bottom interface after aging, but they disappeared again and thus （Cu,Ni, Au ）0Sn5 IMC thickness increased considerably. The influence of reflow times during the flip chip bonding （as-bonded condition） on the characteristics of interfacial IMCs was weakened when subjected to the aging process.

关键词： lead free solder flip chip aging

hEAT TRANSFER ANALySIS duRING ROLLING OF ThIN SLAB IN CSP

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Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 244-250页

作者： W.F. Wu y.h. Feng X.X. Zhang Inner Mongolia University of Science and Technology Baotou 014010 China University of Science and Technology Beijing Beijing 100083 China

A mathematical model has been built to numerically predict the thermal history of thin slab during CSP （compact strip process） rolling. To estimate the temperature distribution in the slab mare accurately, the mathematical model combines heat transfer in the slab, in the roll, and at the roll-slab interface during bite. The numerical results agree with on-site running data, which proves the reliabili~, of the mathematical model. The results show that roll chilling has a significant effect on the temperature distribution in the slab.

关键词： numerical simulation heat transfer CSP(compact strip process) rolling thermal process

EFFECT OF LASER INPUT ENERGy ON AuSn_x INTERMETALLIC COMPOUNDS FORMATION IN SOLDER JOINTS WITh DIFFER-ENT ThICKNESS OF Au SURFACE FINISh ON PADS

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Acta Metallurgica Sinica(English Letters) 2008年第3期21卷 183-190页

作者： W. Liu C.Q. Wang y.h. Tian M.y. Li Department of Electronics Packaging Technology State Key Lab of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Shenzhen Graduate School of harbin Institute of Technology Shenzhen 518055 China

Formation of AuSnx intermetallic compounds （IMCs） in laser reflowed solder joints was investigated. The results showed that few IMCs formed at the solder/0. 1μm Au interface. Needlelike AuSn4 IMCs were observed at the solder/0.5μm Au interface. In Sn-2.0Ag-O,75Cu-3,0Bi and Sn-3.5Ag-O.75Cu solder joints, when the laser input energy was increased, AuSn4 IMCs changed .from a layer to needlelike or dendritic distribution at the solder/0.9μm Au interface. As for the solder joints with 4.0 μm thickness of Au surface finish on pads, AuSn4 , AuSnx, AuSn IMCs, and Au2Sn phases formed at the interface. Moreover, the content of AuSnx IMCs, such as, AuSn4 and AuSn2, which contained high Sn concentration, would become larger as the laser input energy increased. In the Sn-37Pb solder joints with 0.9 μm or 4.0 μm thickness of the Au surface finish on pads, AuSn4 IMCs were in netlike distribution. The interspaces between them were filled with Pb-rich phases.

关键词： Laser soldering Inlermetallics Au films