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Microstructure and Mechanical Properties of Dissimilar Double-Side Friction Stir Welds Between Medium-Thick 6061-T6 Aluminum and Pure Copper Plates

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Acta Metallurgica Sinica(English Letters) 2022年第12期35卷 2027-2046页

作者： J.x.Tang L.Shi C.S.Wu M.x.Wu S.gao MOE Key Lab for Liquid-Solid Structure Evolution and Materials Processing Institute of Materials JoiningShandong UniversityJinan 250061China State Grid Henan Electric Power Research Institute Zhengzhou 450052China School of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan250353China

It is difficult to achieve Al/Cu dissimilar welds with good mechanical properties for medium-thick plates due to the inherent high heat generation rate at the shoulder-workpiece contact interface in conventional friction stir ***,doubleside friction stir welding is innovatively applied to join 12-mm medium-thick 6061-T6 aluminum alloy and pure copper dissimilar plates,and the effect of welding speeds on the joint microstructure and mechanical properties of Al/Cu welds is systematically *** reveals that a sound Al/Cu joint without macroscopic defects can be achieved when the welding speed is lower than 180 mm/min,while a nonuniform relatively thick intermetallic compound(IMC)layer is formed at the Al/Cu interface,resulting in lots of local microcracks within the first-pass weld under the plunging force of the tool during friction stir welding of the second-pass,and seriously deteriorates the mechanical properties of the *** the increase of welding speed to more than 300 mm/min void defects appear in the joint,but the joint properties are still better than the welds performed at low welding speed conditions since a continuous uniform thin IMCs layer is formed at the Al/Cu *** maximum tensile strength and elongation of Al/Cu weld are,respectively,135.11 MPa and 6.06%,which is achieved at the welding speed of 400 mm/*** addition,due to the influence of welding distortion of the first-pass weld,the secondpass weld is more prone to form void defects than the first-pass weld when the same plunge depth is applied on both *** double-side friction stir welding is proved to be a good method for dissimilar welding of medium-thick Al/Cu plates.

关键词： Double-side friction stir welding Medium-thick plate Dissimilar welding Microstructures Intermetallic compounds Mechanical properties

Improving high-temperature mechanical properties of cast CrFeCoNi high-entropy alloy by highly thermostable in-situ precipitated carbides

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Journal of Materials Science & Technology 2021年第13期72卷 29-38页

作者： x.W.Liu N.gao J.Zheng y.Wu y.y.Zhao Q.Chen W.Zhou S.Z.Pu W.M.Jiang Z.T.Fan State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China Institute of Nuclear Physics and Chemistry China Academy of Engineering PhysicsMianyang 621999China State Key Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China School of Materials Engineering Purdue UniversityWest LafayetteIN 47907USA Southwest Technology and Engineering Research Institute Chongqing 400039China Center for Electron Microscopy Wuhan UniversityWuhan 430072China

The Cr Fe Co Ni high-entropy alloy(HEA)exhibits excellent mechanical properties at lower temperatures due to its low stacking-fault energy,however,its medium-and high-temperature strengths are still *** consideration of the potential diversified applications,more strengthening approaches except for the previously proposed L12 phase hardening deserve further exploration due to its rapid coarsening tendency at high ***,we achieved significant high-temperature strengthening of the cast Cr Fe Co Ni HEA by in-situ precipitation of highly thermostable *** with 0.5 at.%and 1 at.%niobium and carbon were prepared by simple casting processes,*** cast,solute solution and aging.A highly thermostable microstructure was formed,which comprises very coarse grains accompanied with extensive thermostable carbide precipitates embedded,including submicrometer coherent Nb C particles in grain interiors and intergranular coherent M_(23)C_(6)*** high thermostability of microstructure,which is beneficial for the high-temperature loading,is ascribed to the synergy of lacking growth driving force and Zenner pinning effect by the *** properties tested at 673,873 and1073 K show that the yield strength and ultimate tensile strength are significantly increased by Nb/C doping,along with the elongation escalation at higher *** strengthening is mainly due to the precipitation hardening of carbide particles.

关键词： High-entropy alloy Carbides Precipitation High-temperature property Strengthening

Heat Loss Calculation of Compound Honeycomb Solar Collector

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Journal of Thermal Science 1993年第4期2卷 254-259页

作者： x.S.Ge y.Z.Zhang H.L.Huang J.W.gao Dept.of Engineering Thermophysics Univ.of Science and Technology of China

A simplified technique is described for calculating the heat loss coefficient from the absorber of the solar flat-plate collector with a combined *** problem is treated in two ways:the coupled mode and the decoupled *** the analysis,the cell wall and glass cover are assumed to be specularly reflecting and diffusely emitting surfaces,while the absorber is a diffusely reflecting and emitting *** influences of emissivities of the absorber and the cell wall as well as the aspect ratio on the heat loss coefficient are *** theoretical results are compared with experimental data reported in the literature,and the agreement is good.

关键词： numerical heat transfer honeycomb solar collector

Experimental and numerical study of the effect of pulsatile flow on wall displacement oscillation in a flexible lateral aneurysm model

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Acta Mechanica Sinica 2019年第5期35卷 1120-1129页

作者： L.Z.Mu x.y.Li Q.Z.Chi S.Q.yang P.D.Zhang C.J.Ji y.He G.gao School of Energy and Power Engineering Dalian University of TechnologyDalian 116024China School of Biomedical Engineering Capital Medical UniversityBeijing 100069China The First Affiliated Hospital of University of Science and Technology of China Hefei 230036China

This study experimentally and numerically investigated the effect of pulsatile flow of different frequencies and outflow resistance on wall deformation in a lateral aneurysm.A method for constructing a flexible aneurysm model was developed,and a self-designed piston pump was used to provide the pulsatile flow conditions.A fluid-structure interaction simulation was applied for comparison with and analysis of experimental *** maximum wall displacement oscillation increased as the pulsation frequency and outflow resistance increased,especially at the aneurysm *** is an obvious circular motion of the vortex center accompanying the periodic inflow fluctuation,and the pressure at the aneurysm dome at peak flow increased as the pulsatile flow frequency and terminal flow resistance *** results could explain why abnormal blood flow with high frequency and high outflow resistance is one of the risk factors for aneurysm rupture.

关键词： Lateral aneurysm In vitro experiment Pulsatile flow Wall displacement oscillation Fluid-structure interaction simulation

单个流体包裹体成分激光剥蚀原位分析方法及其在矿床学中的应用

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大地构造与成矿学 2025年第1期49卷 130-141页

作者：高振丽杨武斌屈潘中国科学院广州地球化学研究所矿物学与成矿学重点实验室/广东省矿物物理与材料研究开发重点实验室广东广州510640

流体包裹体是矿物晶体生长过程中或生长后被捕获的微小珠滴,可以直接保存有关古流体的物理和化学信息,被广泛应用于矿床学研究。单个流体包裹体激光剥蚀分析能够原位测量流体包裹体中的多种元素组成,是有效检测成矿流体组成的重要分析手... 详细信息

流体包裹体是矿物晶体生长过程中或生长后被捕获的微小珠滴,可以直接保存有关古流体的物理和化学信息,被广泛应用于矿床学研究。单个流体包裹体激光剥蚀分析能够原位测量流体包裹体中的多种元素组成,是有效检测成矿流体组成的重要分析手段,目前主要有LA-ICP-MS、LIBS和LA-ICP-AES等方法,其中以LA-ICP-MS的优势最为明显。本文对流体包裹体原位分析过程中包裹体选择策略、包裹体剥蚀方法、检测测量方法及其定量计算原理等方面的研究进展进行综述,并认为光谱和质谱的联用分析技术可以有效地提高分析精确度和准确度,是未来单个流体包裹体原位分析应该重点发展的方向。同时,总结了近年来单个流体包裹体成分分析在矿床学研究中的重要应用和贡献,包括成矿流体的来源、成矿元素的迁移和沉淀过程。

关键词：流体包裹体微区分析激光剥蚀电感耦合等离子质谱仪激光诱导击穿光谱仪

Development of dipole magnet power supply for BEPC-II energy upgrading project

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Radiation Detection Technology and Methods 2019年第2期3卷 32-36页

作者： x.L.Guo B.Chen C.Han y.gao University of Chinese Academy of Sciences Beijing 100049China Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China Dongguan Neutron Science Center Dongguan 523803China

Purpose In order to make BEPC-II to run at a higher energy,the Institute of High Energy Physics undertook an upgrading *** of the important factors limiting the energy boost is the power and performance of the dipole magnet power supplies;therefore,these four magnet power supplies are developed for the BEPC-II *** The power supplies adopt topologies of thyristor rectifiers to realize a high-power *** the control unit of each power supply,a digital current closed loop is adopted,and the key components in the feedback loop are thermostatically *** order to improve the performances of the power supplies,analog voltage regulators are added to the inner control *** These four power supplies have been tested and have already been officially used in BEPC-II,and their powers have reached the requirements of the *** test results of the current stability are described and shown in this paper,which testifies that the stabilities meet the design *** A digital control is applied to each SCR rectifier *** performances of the power supplies are improved by the combination of digital current control loops and the analog voltage control loops,which makes the performances of the dipole magnet power supplies meet the requirements of the upgrading project.

关键词： SCR rectifier Dipole magnet power supply Stability BEPC-II

ExPERIMENTAL AND CLINICAL TRIAL OF ALBENDAZOLE IN THE TREATMENT OF CLONORCHIASIS SINENSIS

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中华医学杂志(英文版) 1991年第1期104卷 27-31页

作者： y H Liu x G Wang P gao M x Qian Chongqing University of Medical Sciences.

Rats and dogs experimentally infected with Clonorchias sinensis metacercariae were treated orally with albendazole. Necropsy done seven days after treatment revealed that the worm reduction rates were 83.6% and 96.8% respectively. Clinically, 131 patients were treated with 3 different dosage regimens in 3 study groups. In patients receiving 5 mg/kg b.i.d, for 7 consecutive days, the stool egg negative conversion rates 1-month and 6-month post treatment were 90% and 92.6%, while in patients receiving 10 mg/kg b.i.d, for 7 consecutive days the rates were both 100%. In another group of patients receiving 1:0 mg/kg b.i.d, for 3 consecutive days, the 1-month and 3-month average stool egg conversion rates after treatment were only 40.0% and 28.3% respectively. The side reactions of albendazole were mild and transient. The liver and renal function tests, electrocardiography and blood and urine examinations showed no remarkable changes before and after treatment. The therapeutic effect of albendazole is comparable to praziquantel. It has the advantage of clearing various intestinal helminthic infections simultaneously, very low toxicity, excellent tolerance and relatively low cost, though its treatment course for clonorchiasis needs 7 days.

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Synergistic O^(2-)/Li^(+) Dual Ion Transportation at Atomic Scale

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Research 2019年第1期2019卷 1260-1267页

作者： F.Q.Meng Q.H.Zhang A.gao x.Z.Liu J.N.Zhang S.y.Peng x.Lu L.Gu H.Li Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China School of Materials Sun Yat-Sen UniversityGuangzhou 510275China College of Materials Science and Engineering Jiangxi University of Science and TechnologyJiangxi 341000China Songshan Lake Materials Laboratory DongguanGuangdong 523808China School of Physical Sciences University of Chinese Academy of SciencesBeijing 100049China

Te ion migration during electrochemical process is a fundamental scientifc issue for phase transition behavior and of technical importance for various functional devices,where cations or anions are active under electrical *** only one type of functional ion,O^(2-)or Li^(+),is activated due to their diferent migration energy barriers,cooperated by the valence change of other immobile ions in the host lattice matrix,e.g.,Co^(2+)/Co^(3+)and Mn^(3+)/Mn4+redox couples,owing to the charge *** we select spinel Li4Ti5O12 as anode and construct an all-solid-state battery under a transmission electron microscope;a synergistic transportation of O^(2-)and Li^(+)driven by an electrical bias was directly observed at the atomic scale.A small amount of oxygen anions was extracted frstly as a result of its lowest vacancy formation energy under 2.2 V,leading to the vertical displacement of *** to 2.7 V,an ordered phase with both Li-and O-defciency *** Li^(+)and O^(2-)ions are simultaneously extracted out from the[LiO_(4)]tetrahedra due to the electroneutrality *** migration paths of O and Li have been proposed and verifed by frst-principles *** results reveal a brand new synergistic ion migration manner and may provide up-to-date insights on the transportation process of lithium ion conductors.

关键词： synergistic battery migration

CALCULATION OF THE DAMPING OF THE Zn-27Al ALLOy BASED ON THE MICRO INTERFACE SLIDING MODEL

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Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 228-234页

作者： y.Z. Zhao Q. gao y.C. Liu School of Civil Engineering Southwest Jiaotong University Chengdu 610031 China Department of Applied Mechanics and Engineering Southwest Jiaotong University Chengdu 610031 China

The microstructures of the Zn-27Al alloy after modification, solid-solution treatment, and natural aging were studied. It was clarified why the damping properties of Zn-27Al alloys, after treatment, had advanced most on the basis of analyzing the microstructures. Approximate expressions have been educed, which can be used to quantificationally work out the damping of the Zn-27Al alloy on the basis of the micro interface sliding model. By comparing the testing damping properties of the foundry Zn-27Al alloys and the Zn-27Al alloys after modification, solid solution, and natural aging, it was shown that the expressions were rational.

关键词： modification solid solution and aging damping micromechanism micro interface sliding model