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KINETIC STUDY OF SPINEL LiMn_2O_4 SYNTHESIZED BY SOLID REACTION WITH SOFT-CHEMICAL METHOD

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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 512-518页

作者： C.q. Xu Y. W. Tian Y. C. Zhai Z.j. Guo Z. q. Huang School of Materials and Metallurgy Northeastern University Shenyang 110004 China

The differential thermal analysis （DTA） curves were measured at different heating rates in flowing air for studying the synthesis of the spinel LiMn2O3 with Li2CO3 and MnO2, The reaction began at about 503K, and finished at about 873K. The apparent activation energy of Kissinger method was about ***^-1, the reaction orderwas 1.67, the frequency factor was 7.81×10^9, and therefore the dinetic epuation was dδ/dt=A·exp（- E/RT）·（1-δ）^n=7.81×10^9, exp（-122770/RT）·（l-δ）^1.67 . Coats-Redfem integral method was used to analyze the DTA curves of the samples at different heating rates, and the calculated apparent activation energy and frequency factor were 112. 13kj· mol^-1 and 1.18 × 10^9, respectively, rather close to that of Kissinger method. X-ray diffraction （XRD） and scanning electron microscope （SEM） results shown that the synthesized LiMn2O3 possesses pure phase, regular shape and normal particle distribution.

关键词： lithium manganese oxides synthesized kinetics Kissinger method,Coats-Redfern integral method

A compliant surgical robotic instrument with integrated IPMC sensing and actuation

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International journal of Smart and Nano Materials 2012年第3期3卷 188-203页

作者： A.j.McDaid S.q.Xie K.C.Aw Mechanical Engineering Department University of AucklandAuckland 1142New Zealand

Robotic assisted surgery is becoming widely adopted by surgeons for a number of reasons,which include improved instrumentation control and dexterity as well as faster patient recovery times and cosmetic *** assisted surgery is currently one of the fastest growing applications in *** the traditional robotic actuators which are currently used have advanced performance which can,in some aspects,surpass that of humans,they simply do not have the capabilities and diversity required to meet the demand for new applications in robotic *** transducers which have advanced capabilities and which allow safe operation in delicate environments are *** polymer-metal composites(IPMCs)have extensive desirable characteristics when compared with traditional actuators and as their transduction mechanisms can mimic biological muscle they have much potential for future advanced biomedical and surgical *** this research,a complete two degree-of-freedom(2DOF)surgical robotic instrument has been developed,which with the attachment of surgical tools(scalpel,etc.)has the ability to undertake surgical *** system integrates an IPMC sensor and actuator at each joint.A gain scheduled(GS)controller,which is tuned with an iterative feedback tuning(IFT)algorithm,has been developed to ensure an accurate and adaptive *** main advantages of this device over traditional devices are the improved safety through a natural compliance of the joints as well as the mechanical simplicity which ensures ease of miniaturisation for minimally invasive surgery(MIS).The components of the system have been tested and shown to have the capabilities required to operate the device for certain surgical procedures,specifically a device work envelope of 1600 mm^(2),compliance of 0.0668 m/N while still maintaining enough force to cut tissue,IPMC sensor accuracy between 3-22%and a control system which has shown to guarantee zero steady state error.

关键词： ionic polymer-metal composite surgical robotics iterative feedback tuning

Distinct dendritic α phase emerging on the surface of primary α phase in a compressed near-α titanium alloy

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journal of Materials Science & Technology 2018年第4期34卷 666-669页

作者： Z.Liu Z.B.Zhao j.R.Liu q.j.Wang R.Yang Institute of Metal Research Chinese Academy of Sciences School of Materials Science and Engineering University of Science and Technology of China

The characteristic of the surface morphology of primary α phase was studied in a deformed near-α tita- nium alloy. Dendritic α phase emerged on the surfaces of primary α phase when the alloy was air-cooled in α ＋β phase field after deformation. The dendritic α grain has the same orientation with its original primary α grain. The formation of the dendritic α phase could be explained by interface instability in epi- taxial growth process of the primary α phase. The dislocations induced by deformation could facilitate the formation of dendritic α phase leading to the dendritic α phase and more obvious with the increase of strain. The growth of dendritic α phase was finally limited by the nucleation of second α phase with cooling.

关键词： Epitaxial growth Dendritic α phase Microstructure Interface instability Hot deformation

Optimal Split Ratio in Small High Speed PM Machines Considering Both Stator and Rotor Loss Limitations

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CES Transactions on Electrical Machines and Systems 2019年第1期3卷 3-11页

作者： j.Ma Z.q.Zhu Department of Electrical and Electronic Engineering The University of SheffieldSheffieldS13JDU.K.

The split ratio which is defined as the ratio between rotor and stator outer diameters is critical for permanent magnet(PM)*** this paper,the split ratio in small high speed PM machines is optimized analytically by considering both stator and rotor loss *** this way,the thermal constrains in both stator and rotor parts can be taken into *** shows that both losses can significantly affect the optimal split ratio and the machine *** considering the influence of rotor losses,especially the rotor eddy current loss,the optimal split ratio is increased significantly in certain *** output torque is calculated analytically and the influences of several key design parameters on the optimal split ratio,***/pole combinations and magnet materials,are also investigated in ***,finite element(FE)analyses are carried out for validating of the analytical model.

关键词： Index Terms-High speed permanent magnet split ratio.

Current diffusion and efficiency droop in vertical light emitting diodes

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Chinese Physics B 2019年第1期28卷 561-569页

作者： R q Wan T Li Z q Liu X Y Yi j X Wang j H Li W H Zhu j M Li L C Wang State Key Laboratory of High Performance Complex Manufacturing College of Mechanical and Electrical EngineeringCentral South University Semiconductor Lighting Technology Research and Development Center Institute of SemiconductorsChinese Academy of Sciences College of Materials Science and Opto-Electronic Technology University of Chinese Academy of Sciences

Current diffusion is an old issue, nevertheless, the relationship between the current diffusion and the efficiency of light emitting diodes(LEDs) needs to be further quantitatively clarified. By incorporating current crowding effect(CCE) into the conventional ABC model, we have theoretically and directly correlated the current diffusion and the internal quantum efficiency(IqE), light extraction efficiency(LEE), and external quantum efficiency(EqE) droop of the lateral ***, questions still exist for the vertical LEDs(V-LEDs). Here firstly the current diffusion length L_s(I) and L_s(II) have been clarified. Based on this, the influence of CCE on the EqE, IqE, and LEE of V-LEDs were investigated. Specifically to our V-LEDs with moderate series resistivity, L_s(III) was developed by combining L_s(I) and L_s(II), and the CCE effect on the performance of V-LEDs was investigated. The wall-plug efficiency(WPE) of V-LEDs ware investigated finally. Our works provide a deep understanding of the current diffusion status and the correlated efficiency droop in V-LEDs, thus would benefit the V-LEDs' chip design and further efficiency improvement.

关键词： efficiency droop vertical light emitting diodes current crowding effect current blocking layer

Effect of stress profile on microstructure evolution of cold-drawn commercially pure aluminum wire analyzed by finite element simulation

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journal of Materials Science & Technology 2018年第7期34卷 1214-1221页

作者： Y.K.Zhu q.Y.Chen q.Wang H.Y.Yu R.Li j.P.Hou Z.j.Zhang G.P.Zhang Z.F.Zhang Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of Sciences National quality Supervision & Inspection Center of Electrical Equipment Safety Performance Zhejiang Huadian Equipment Testing Institute

The evolution of microstructure in the drawing process of commercially pure aluminum wire （CPAW） does not only depend on the nature of materials, but also on the stress profile. In this study, the effect of stress profile on the texture evolution of the CPAW was systematically investigated by combining the numerical simulation and the microstructure observation. The results show that the tensile stress at the wire center promotes the formation of 〈111〉 texture, whereas the shear stress nearby the rim makes little contribution to the texture formation. Therefore, the 〈111 〉 texture at the wire center is stronger than that in the surface layer, which also results in a higher microhardness at the center of the CPAW under axial loading.2017 Published by Elsevier Ltd on behalf of The editorial office of journal of Materials Science ＆ Technology.

关键词： Commercially pure aluminum wire Cold drawing Texture Finite element simulation Stress profile

Inhibiting effect of I-phase formation on the plastic instability of the duplex structured Mg-8Li-6Zn-1.2Y(in wt.%)alloy

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镁合金学报(英文) 2023年第6期11卷 2196-2204页

作者： B.j.Wang D.K.Xu X.q.Zhuang L.Y.Sheng School of Environmental and Chemical Engineering Shenyang Ligong UniversityShenyang110159China Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China Peking University Shenzhen InstituteShenzhen Key Lab Human Tissue Regenerate&RepairShenzhen 518057China

In this work,the tensile behaviors of Mg-8%Li and Mg-8%Li-6%Zn-1.2%Y alloys at ambient temperature were investigated and *** revealed that the plastic instability of Mg-8%Li alloy was quite remarkable and the variation range of serrated flowing stress can reach5 *** the Mg-8%Li-6%Zn-1.2%Y alloy,the formation of I-phase(Mg_(3)Zn_(6)Y)can simultaneously enhance the tensile strength and eliminate the plastic instability phenomenon,whilst its ductility was *** in-situ tensile tests revealed that for the Mg-8%Li alloy,the severity and number of slip traces present in bothα-Mg andβ-Li matrix phases increased remarkably with the applied tensile ***,slip traces were quite fine inβ-Li matrix phase and could be clearly observed when the applied tensile strain exceeded 18%.Due to the incompatibility of plastic deformation occurred in two matrix phases,the induced strain concentration atα-Mg/β-Li interfaces caused their subsequent *** the Mg-8%-6%Zn-1.2%Y alloy,the I-phase distributed atα-Mg/β-Li interfaces suppressed the plastic deformation ofα-Mg matrix phase and the tensile strain was dominated by theβ-Li matrix phase,resulting in the disappearance of plastic ***,the plastic strain would preferentially concentrate at I-phase/β-Li interfaces and subsequently induced the cracking of I-phase.

关键词： Mg-li alloys Microstructure Plastic deformation Basal slip Cracking

EFFECT OF CHROMIUM AND BORON ON ENVIRONMENTAL EMBRITTLEMENT OF FORGED Fe_3Al

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Acta Metallurgica Sinica(English Letters) 1997年第3期10卷 188-191页

作者： j.q. Su S.j Gao and Z.q. Hu (Liaoning Key Laboratory for Materials and Hydrogen, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110015, China)(National Key Laboratory for RSA, Institute of Metal Research, Chinese Academy of Sciences, Inst of Metal Research Chinese Acad of Sciences Shenyang China

The effects of addition of chromium or boron on room temperature tensile properties,fracture behavior and susceptibility to test environments (air vs. vacuuwi of forged Fe3Al have been investigated. The results indicated that both chromium and boron result in increasing room temperuture ductility and fracture strength of the Fe3Al alloy whether tested in air or in vacuum. The susceptibility to test envimnment was described with the embrittlement index I: I=(δv-δA)/δv. The embrittlement indexes, for Fe-30Al, Fe-30Al-4Cr and Fe-30Al-0. 13B (at. %), are 24%, 37% and 29%,respectively. Scanning electron microscope examination of fracture surface revealed that the fracture mode of the three alloys remains unchanged, and all of them exhibited a transgranular cleavage fracture mode when tested in vacuum or air.

关键词： chromium boron Fe_3Al enviromental embrittlement

Synthesis and Characterization of Fe_(50)Cr_(14)Mo_(14)C_(14)B_6Gd_2 Bulk Amorphous Steel

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journal of Materials Science & Technology 2010年第9期26卷 783-786页

作者： M. Iqbal j.I. Akhter H.F. Zhang Z.q. Hu Physics Division Pakistan Institute of Nuclear Science &: Technology P.O. Nilore Islamabad Pakistan Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China

Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical *** steel was synthesized by Cu mold casting technique using 1-2N pure *** of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron *** activation energies were calculated by Kissinger equation and it was found that the steel had better stability against *** properties like Vicker s hardness,nanohardness,elastic modulus and elastic recovery of as-cast and annealed samples were *** was concluded that the present steel had good glass-forming ability（GFA） and mechanical properties.

关键词： Bulk amorphous steels Activation energy Glass-forming ability Mechanical properties