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Basic features of the multiscale interaction between tearing modes and slab ion-temperature-gradient modes

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Chinese Physics B 2019年第12期28卷 237-247页

作者： l Wei z X Wang J Q li z Q Hu Y Kishimoto Key laboratory of Materials Modification by laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China Southwestern Institute of Physics Chengdu 610041China Graduate School of Energy Science Kyoto UniversityGokashoUjiKyoto 1-0011Japan

Nonlinear interaction between tearing modes(TM) and slab ion-temperature-gradient(ITG) modes is numerically investigated by using a landau fluid model. It is observed that the energy spectra with respect to wavenumbers become broader during the transition phase from the ITG-dominated stage to TM-dominated stage. Accompanied with the fast growth of the magnetic island, the frequency of TM/ITG with long/short wavelength fluctuations in the electron/ion diamagnetic direction decreases/increases respectively. The decrease of TM frequency is identified to result from the effect of the profile flattening in the vicinity of the magnetic island, while the increase of the frequencies of ITG fluctuations is due to the eigenmode transition of ITG induced by the large scale zonal flow and zonal current related to TM. Roles of zonal current induced by the ITG fluctuations in the instability of TM are also analyzed. Finally, the electromagnetic transport features in the vicinity of the magnetic island are discussed.

关键词： magnetic reconnection tearing modes magnetohydrodynamics drift waves nonlinear phenomena

landslide Displacement Prediction Based on Time Series and PSO-BP Model in Three Georges Reservoir, China

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Journal of Earth Science 2024年第3期35卷 1079-1082页

作者： Dexiang Gao kou li Yuncheng Cai Tao Wen School of Geosciences Yangtze UniversityWuhan 430100China School of Science Yunnan Agricultural UniversityKunming 650201China

0 INTRODUCTION landslides are one of the most frequent geological disasters in the world(Wen et al.,2020;Froude and Petley,2018),which have occurred frequently and widely distributed in China for a long *** landslides are essentially a complex multidimensional nonlinear dynamic system affected by its own geological conditions and external factors(Ma et al.,2021;Wang et al.,2019),including geotechnical characteristics,hydrogeology,geomorphologic conditions,climate,and weathering(Ma et al.,2020).The interaction of these factors makes the change of landslide displacement random,fuzzy and variable(Park and Michalowski,2017),and also brings great difficulties to the landslide displacement prediction(Ma et al.,2018).

关键词： landslide landslide weathering

Effect of post weld artificial aging and water cooling on microstructure and mechanical properties of friction stir welded 2198-T8 Al-li joints

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Journal of Materials Science & Technology 2022年第28期123卷 92-112页

作者： Y.Tao z.zhang P.Xue D.R.Ni B.l.Xiao z.Y.Ma Institute of Metal Research Chinese Academy of SciencesShenyang 110016China

Friction stir welding(FSW)under both air cooling and water cooling conditions with welding parameters of 800-1200 rpm rotation rates and 50-200 mm/min welding speeds was carried out on 2198-T8 Al-li alloys,and post weld artificial aging was performed on the air cooled *** welding defects other than lazy S were observed in the nugget zone(Nz)for all *** air cooling condition,the lowest hardness zone(lHz)occurred in the heat affected zone(HAz).FSW resulted in gradual dissolution of original T_(1),θ′andδ′/β′from the base material(BM)to the thermo-mechanically affected zone(TMAz),and complete dissolution of all precipitates in the Nz withδ′/β′and Guinier-Preston zones precipitating during *** air cooled joints exhibited no noticeable changes in intrinsic tensile strength with a joint strength reaching 81.3%of the BM,but varied elongation with welding parameters,which was closely related to failure in the Nz and fracture along lazy *** weld artificial aging led to the largest hardness recovery in the TMAz but smaller hardness recovery in the initial lHz and the *** aging kinetics across the joint was determined by volume fraction of both original precipitate dissolu-tion during welding and coarse particles formed during aging,and by dislocation density inherited from *** weld artificial aging greatly enhanced the joint strength with the ultimate tensile strength reaching 87.3%of the *** compared to air cooling condition,water cooling hardly affected the Nz hardness and did not improve the joint strength,and the reason was discussed in light of precipitates,hardness changes and fracture behavior.

关键词： Friction stir welding Aluminum-lithium alloys Microstructure Mechanical properties

NUMERICAl SIMUlATION STUDY ON DEFORMATION UNIFORMITY OF EQUAl CROSS SECTION lATERAl EXTRUSION

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Acta Metallurgica Sinica(English letters) 2004年第1期17卷 61-63页

作者： z.l.Chang J.l.Song N.H.Hao Department of Materials Engineering Taiyuan Heavy Machinery Institute Taiyuan 030024 ChinaDepartment of Materials Engineering Taiyuan Heavy Machinery Institute Taiyuan 030024 ChinaDepartment of Materials Engineering Taiyuan Heavy Machinery Institute Taiyuan 030024 China

Equal cross section lateral extrusion (ECSlE) is an effective method realizing pure shear deformation. The influence of friction factor on the deformation uniformity of ECSlE was investigated with rigid plastic finite element method. The result shows that the non-uniform deformation in extrusion is caused mainly by the friction between workpiece and die. The higher the friction factor is, the more uneven plastic deformation resulted in extruded workpiece. The relation curve of deformation uniformity vs. friction factor was drawn based on the analysis result. The curve can be used as a basis of ECSlE process design.

关键词： equal cross section lateral extrusion strain finite element method

STUDY ON THE FINITE ElEMENT NUMERICAl SIMUlATION OF SHEET METAl FORMING

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Acta Metallurgica Sinica(English letters) 2004年第3期17卷 299-302页

作者： J.l.Song D.J.Hu z.l.Chang T.Y.li z.B.Jiang School of Mechanical Engineering Shanghai Jiaotong University Shanghai 200030 China Department of Materials Engineering Taiyuan Heavy Machinery Institute Taiyuan 030024 China

Based on the Finite Element Theory of Rigid Plastic,relevant problems during plas-tic simulation on sheet metal forming were technologically studied and simplified;a simplified model of the blank holder during the drawing process was established and the effects of related parameters on the forming processes were also *** the same time,a finite--element numerical simulation program SPID was *** distribution of strain and relationship of stress--stroke simulated were compared with experimented,the results are well coincided with each *** is verified that the analytical program is reliable.

关键词： sheet metal forming finite-element numerical simulation

Tailoring precipitation/properties and related mechanisms for a high-strength aluminum alloy plate via low-temperature retrogression and re-aging processes

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Journal of Materials Science & Technology 2022年第25期120卷 15-35页

作者： l.G.Hou H.Yu Y.W.Wang l.You z.B.He C.M.Wu D.G.Eskin l.Katgerman l.z.zhuang J.S.zhang State Key laboratory for Advanced Metals&Materials University of Science&Technology BeijingBeijing 100083China BCAST Brunel University LondonKingston LaneUxbidge Middlesex UB83PHUnited Kingdom Institute of mineral resources Chinese Academy of Geological SciencesBeijing 100037China Nanjing Advanced Transportation Equipment New Technology Research Institute Nanjing 211800China Tomsk State University Tomsk634050Russian Federation Katgerman Aluminium Technology van Beuningenlaan 102334CC LeidenNetherlands Department of Materials Science and Engineering Delft University of TechnologyMekelweg 22628CD Delftthe Netherlands

The retrogression and re-aging(RRA)processes,aimed mainly at tailoring intergranular precipitates,could significantly improve the corrosion resistance(i.e.,stress corrosion cracking resistance)without considerably decreasing the strength,which signifies that an efficient control of the size,distribution and evolution of intergranular and intragranular precipitates becomes critical for the integrated properties of the(mid-)thick high-strength Al alloy *** to RRA process with retrogression at200℃ (T77),this study investigated the impact of a modified RRA process(MT77)with lower retrogression temperatures(155-175℃ )and first-stage under-aging on the properties of a high-strength AA7050 Al alloy,in combination with detailed precipitate *** study showed that the strength/microhardness of the RRA-treated alloys decreased with raising retrogression temperature and/or prolonging retrogression time,along with the increased electrical *** rapid responsiveness of microstructure/property typical of retrogression at 200℃ was obviously postponed or decreased by using MT77 process with longer retrogression time that was more suitable for treating the(mid-)thick *** the other hand,higher retrogression temperature facilitated more intragranularηprecipitates,coarse intergranular precipitates and wide precipitate free zones,which prominently increased the electrical conductivity alongside a considerable strength loss as compared to the MT77-treated *** the preferred MT77 process,the high strength approaching T6 level as well as good corrosion resistance was ***,though a relatively homogeneous through-thickness strength was obtained,some small discrepancies of properties between the central and surface areas of an 86-mm thick 7050 Al alloy plate were observed,possibly related to the quenching *** precipitate evolution and mechanistic connection to the properties were discussed and reviewed for high-strengt

关键词： Aluminum alloy Heat treatment Precipitation Strength Grain boundary

Different Diffusion Behavior of Cu and Ni Undergoing liquidesolid Electromigration

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Journal of Materials Science & Technology 2014年第12期30卷 1235-1242页

作者： M.l.Huang z.J.zhang H.T.Ma l.D.Chen Electronic Packaging Materials laboratory School of Materials Science & Engineering Dalian University of Technology IC Packaging Department Xi'an Institute of Microelectronic Technology

The diffusion behavior of Cu and Ni atoms undergoing liquidesolid electromigration（l-S EM） was investigated using Cu/Sn/Ni interconnects under a current density of 5.0 103A/cm2 at 250℃. The flowing direction of electrons significantly influences the cross-solder interaction of Cu and Ni atoms, i.e., under downwind diffusion, both Cu and Ni atoms can diffuse to the opposite interfaces; while under upwind diffusion,Cu atoms but not Ni atoms can diffuse to the opposite interface. When electrons flow from the Cu to the Ni, only Cu atoms diffuse to the opposite anode Ni interface, resulting in the transformation of interfacial intermetallic compound（IMC） from Ni3Sn4into（Cu,Ni）6Sn5and further into [（Cu,Ni）6Sn5t Cu6Sn5], while no Ni atoms diffuse to the opposite cathode Cu interface and thus the interfacial Cu6Sn5 *** electrons flow from the Ni to the Cu, both Cu and Ni atoms diffuse to the opposite interfaces,resulting in the interfacial IMC transformation from initial Cu6Sn5into（Cu,Ni）6Sn5and further into[（Cu,Ni）6Sn5t（Ni,Cu）3Sn4] at the anode Cu interface while that from initial Ni3Sn4into（Cu,Ni）6Sn5and further into（Ni,Cu）3Sn4at the cathode Ni interface. It is more damaging with electrons flowing from the Cu to the Ni than the other way.

关键词： Cu/Sn/Ni Electromigration Cross-solder interaction Interfacial reaction Diffusion

Towards Transgenic Primates:What can we learn from mouse genetics?

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Science China(life Sciences) 2009年第6期52卷 506-514页

作者： WANG Phillip l. TSIEN Joe z. Brain and Behavior Discovery Institute School of MedicineMedical College of Georgia Yunnan Banna Primate Disease Model Research Center and Shanghai Institute of Brain Functional GenomicsKey Laboratory of Brain Functional GenomicsMOE & STCSMEast China Normal University

Considering the great physiological and behavioral similarities with humans,monkeys represent the ideal models not only for the study of complex cognitive behavior but also for the preclinical research and development of novel therapeutics for treating human *** powerful genetic tech-nologies initially developed for making mouse models are being explored for generating transgenic primate *** review the latest genetic engineering technologies and discuss the potentials and limitations for systematic production of transgenic primates.

关键词： Non-human primate Mouse Transgene Genetics learning Memory disease model

An integrated microfluidic platform for nucleic acid testing

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Microsystems & Nanoengineering 2024年第3期10卷 181-194页

作者： Antao Sun Petra Vopařilová Xiaocheng liu Bingqian kou TomášŘezníček Tomášlednický Sheng Ni JiříKudr Ondřej zítka zdenka Fohlerová Petr Pajer Haoqing zhang Pavel Neužil Ministry of Education Key laboratory of Micro and Nano Systems for Aerospace School of Mechanical EngineeringNorthwestern Polytechnical University127 West Youyi RoadXi’anShaanxi 710072P.R.China Department of Chemistry and Biochemistry Mendel University in BrnoZemědělská161300 BrnoCzech Republic ITD Tech s.r.o Osvoboditelů100573581 BohumínCzech Republic Central European Institute of Technology Brno University of TechnologyPurkyňova 123Brno 61200Czech Republic Department of Electronic and Computer Engineering The Hong Kong University of Science and TechnologyClear Water BayKowloonHong Kong SARChina Department of Microelectronics Faculty of Electrical Engineering and CommunicationBrno University of TechnologyTechnická3058/10Brno 61600Czech Republic Military Health Institute U Vojenskénemocnice 120016200 Praha 6Czech Republic The Key laboratory of Biomedical Information Engineering of Ministry of Education School of Life Science and TechnologyXi’an Jiaotong UniversityXi’anShaanxi 710049P.R.China Bioinspired Engineering and Biomechanics Center(BEBC) Xi’an Jiaotong UniversityXi’an 710049P.R.China

This study presents a rapid and versatile low-cost sample-to-answer system for SARS-CoV-2 *** system integrates the extraction and purification of nucleic acids,followed by amplification via either reverse transcriptionquantitative polymerase chain reaction(RT–qPCR)or reverse transcription loop-mediated isothermal amplification(RT–lAMP).By meeting diverse diagnostic and reagent needs,the platform yields testing results that closely align with those of commercial RT-lAMP and RT‒qPCR *** advantages of our system include its speed and *** assay is completed within 28 min,including sample loading(5 min),ribonucleic acid(RNA)extraction(3 min),and RT-lAMP(20 min).The cost of each assay is≈$9.5,and this pricing is competitive against that of Food and Drug Administration(FDA)-approved commercial *** some RNA loss during on-chip extraction is observed,the platform maintains a potential limit of detection lower than 297 *** makes the system particularly useful in environments where centralized laboratories are either unavailable or inconveniently *** key feature is the platform’s versatility,allowing users to choose between RT‒qPCR or RT‒lAMP tests based on specific requirements.

关键词： testing maintain versatile