用于旋转超声波加工的非接触电能传输耦合器的优化设计

旋转超声波加工设备可以采用非接触电能传输耦合器为高速旋转的超声振子提供电能,以取代传统的接触式碳刷滑环,这种非接触电能传输方式安全、稳定,且对转速没有限制。但由于主次级磁芯之间存在间隙,使其漏磁通较大,功率传输能力较低。为提高非接触旋转耦合器的功率传输能力,采用有限元仿真和实验的方法,通过对比分析不同材质及结构形式耦合器的磁通分布情况、线圈自感、线圈间互感、耦合系数、线圈交流电阻等参数,对耦合器进行了优化设计。优化后的非接触旋转耦合器具有更高的耦合能力及功率传输能力。     

回转式非接触超声电能传输装置有限元仿真和实验研究

对回转式非接触超声电能传输装置进行了有限元仿真分析,得出了其磁力线图、磁场分布云图和磁芯磁场在空气中分布矢量图,以及在不同磁芯线圈间距、不同副边磁芯线圈转速情况下回转式非接触超声电能传输装置的耦合系数、互感曲线、自感曲线和漏感曲线,并搭建实验平台对回转式非接触超声电能传输装置进行了实验研究,验证了有限元仿真结果的正确性。     

旋转超声加工非接触供电模型研究

针对旋转超声加工非接触供电的互感模型和T型模型,结合换能器进行了理论分析和实验研究,并参考非接触供电在其他方面的应用,提出了一种新的适合旋转超声加工的非接触供电模型及其匹配方式,无需考虑耦合系数及原副边线圈间隙过大的问题,具有供电模型简洁、匹配方式简单的优点。根据对比研究的结果搭建了专门的硬件电路,超声压缩实验结果证明了所述模型的可行性和可靠性。     

高速回转液压缸保压性能的动态试验技术

回转液压缸是数控车床的功能部件,它通过拉杆驱动动力卡盘夹紧工件.高速回转液压缸内集成了由两个液控单向阀组成的液压锁,对液压缸保压.常用的试验装置无法在高速旋转的工况下进行液压锁的保压试验.设计提出高速回转液压缸保压性能的动态试验装置,在拉杆上布置应变片测量推拉力,利用非接触式的旋转变压耦合器传输电能和信号.由于供电和信号传输是非接触的、具有无摩擦磨损、干扰小的优点,最高转速达到10 000 r/min.最后利用该装置试验高速回转液压缸的保压性能,试验结果表明,静态时保压性能良好的回转液压缸,旋转时可能保压失败.     

旋转超声加工系统的频率分叉研究

以松耦合变压器构成的非接触电能传输系统与超声波换能器负载共同组成超声加工系统,构建了旋转超声加工的频率与阻抗数值模型,并通过Matlab Simulink平台建立了阻抗模型的仿真计算。结果表明:旋转超声加工的工作频率存在分叉现象,导致超声加工系统可能工作在不同频率点。从实验角度对不同频率点的振动情况进行监测,发现不同频率点的超声能量输出是存在差异的。     

超声振动磨削无线电能传输系统特性分析

为研究超声振动磨削无线电能传输系统特性,对原边匹配电容、原/副边之间的不同距离、轴向力大小、线圈匝数、导线直径等进行了研究。实验表明原边并联电容值越大,电路中电流越大;电路中电流随着原/副边距离的增加,电流呈先下降,后基本不变,再下降的趋势;轴向力越大,电路中电流越大;线圈匝数越大,电流越小;同等条件下,线圈导线直径越小,电路中电流越大。研究结果为实际生产应用提供了参考。     

新型非接触式供电重载过跨车

非接触式供电重载过跨车能够克服传统卷筒加电缆供电方式的运行距离限制,并且具有强大的通讯能力,可以与生产管理系统集成,实现全厂物流自动化。文章以由首钢国际工程技术有限公司设计并制造的非接触式供电重载过跨车为例,介绍了非接触式供电及非接触式通讯的工作原理,以及该过跨车的机械构成及自动化配置,并论述了冷轧厂应用的这种新型过跨车的直接与间接经济效益。生产实践证明,新型过跨车运行稳定,实现自动钢卷跟踪及工艺数据传递,提高了全厂的生产协同能力,并使生产现场美观整齐。     

旋转超声辅助加工装置及其工艺研究

基于传统超声振动理论,提出了一种新型旋转超声辅助加工装置。该装置将超声振动与负载匹配二者相结合,具备旋转超声辅助加工硬脆材料的能力。利用该装置对微波铁氧体材料进行旋转超声辅助钻削加工试验研究,验证了旋转超声辅助磨削可有效降低加工过程中的切削力。同时,在保证刀具和材料安全的前提下,探索了旋转超声辅助加工装置对加工效率的影响。     

基于KRG代理模型的超声悬浮夹具设计

在超精密制造领域,如晶圆、硅片的制造与运输,需要在非接触、超净化条件下进行。为提高非接触式夹具的夹持稳定性,分析了无侧向约束力的超声悬浮夹具存在的不足,设计了一种有侧向约束力的新型超声悬浮夹具。基于KRG代理模型技术,建立了新型超声悬浮夹具的设计模型,并用遗传算法优化了新型超声悬浮夹具的结构参数。为验证新型超声悬浮夹具非接触夹持效果,运用工业视觉测量技术,搭建了试验平台。试验结果表明,新型超声悬浮夹具能够稳定夹持工件。     

激光超声无损检测技术研究进展

随着缺陷检测要求越来越高,非接触式无损检测应用越来越广泛。激光超声无损检测技术作为非接触式无损检测的一种新型检测手段,凭借其显著的优势逐渐受到广泛关注。本文基于激光超声无损检测技术的研究进展,与空气耦合超声、电磁超声、静电耦合超声等主要非接触式无损检测进行了优劣势比较,介绍了激光超声技术国内外研究现状和应用情况,提出了目前激光超声无损检测遇到的技术难点,并对激光超声无损检测技术的发展进行总结和展望。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

Effect of Rare Earth Doping on Impedance,Modulus and Conductivity Properties of Multiferroic Composites:0.5(BiLa_xFe_(1-x)O_3)–0.5(PbTiO_3)

The Lanthanum-doped bismuth ferrite–lead titanate compositions of 0.5(Bi LaxFe1-xO3)–0.5(Pb Ti O3)(x = 0.05,0.10,0.15,0.20)(BLxF1-x-PT) were prepared by mixed oxide method.Structural characterization was performed by X-ray diffraction and shows a tetragonal structure at room temperature.The lattice parameter c/a ratio decreases with increasing of La(x = 0.05–0.20) concentration of the composites.The effect of charge carrier/ion hopping mechanism,conductivity,relaxation process and impedance parameters was studied using an impedance analyzer in a wide frequency range(102–106Hz) at different temperatures.The nature of Nyquist plot confirms the presence of bulk effects only,and non-Debye type of relaxation processes occurs in the composites.The electrical modulus exhibits an important role of the hopping mechanism in the electrical transport process of the materials.The ac conductivity and dc conductivity of the materials were studied,and the activation energy found to be 0.81,0.77,0.76 and 0.74 e V for all compositions of x = 0.05–0.20 at different temperatures(200–300 °C).     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

Using Finite Element and Contour Method to Evaluate Residual Stress in Thick Ti-6Al-4V Alloy Welded by Electron Beam Welding

This work was to reveal the residual stress profile in electron beam welded Ti-6Al-4V alloy plates(50 mm thick) by using finite element and contour measurement methods.A three-dimensional finite element model of 50-mmthick titanium component was proposed,in which a column–cone combined heat source model was used to simulate the temperature field and a thermo-elastic–plastic model to analyze residual stress in a weld joint based on ABAQUS software.Considering the uncertainty of welding simulation,the computation was calibrated by experimental data of contour measurement method.Both test and simulated results show that residual stresses on the surface and inside the weld zone are significantly different and present a narrow and large gradient feature in the weld joint.The peak tensile stress exceeds the yield strength of base materials inside weld,which are distinctly different from residual stress of the thin Ti-6Al-4V alloy plates presented in references before.     

Microstructures and Tensile Properties of Ultrafine-Grained Ni–(1–3.5) wt% SiC_(NP) Composites Prepared by a Powder Metallurgy Route

Silicon carbide nanoparticle-reinforced nickel-based composites(Ni–Si CNP),with a Si CNPcontent ranged from1 to 3.5 wt%,were prepared using mechanical alloying and spark plasma sintering.In addition,unreinforced pure nickel samples were also prepared for comparative purposes.To characterize the microstructural properties of both the unreinforced pure nickel and the Ni–Si CNPcomposites transmission electron microscopy(TEM) was used,while their mechanical behavior was investigated using the Vickers pyramid method for hardness measurements and a universal tensile testing machine for tensile tests.TEM results showed an array of dislocation lines decorated in the sintered pure nickel sample,whereas,for the Ni–Si CNPcomposites,the presence of nano-dispersed Si CNPand twinning crystals was observed.These homogeneously distributed Si CNPwere found located either within the matrix,between twins or on grain boundaries.For the Ni–Si CNPcomposites,coerced coarsening of the Si CNPassembly occurred with increasing Si CNPcontent.Furthermore,the grain sizes of the Ni–Si CNPcomposites were much finer than that of the unreinforced pure nickel,which was considered to be due to the composite ball milling process.In all cases,the Ni–Si CNPcomposites showed higher strengths and hardness values than the unreinforced pure nickel,likely due to a combination of dispersion strengthening(Orowan effects) and particle strengthening(Hall–Petch effects).For the Ni–Si CNPcomposites,the strength increased initially and then decreased as a function of Si CNPcontent,whereas their elongation percentages decreased linearly.Compared to all materials tested,the Ni–Si CNPcomposite containing 1.5% Si C was found more superior considering both their strength and plastic properties.     

Directional Growth of Tin Crystals Controlled by Combined Solute Concentration Gradient Field and Static Magnetic Field

A new method was introduced to achieve directional growth of Sn crystals. Microstructures in liquid(Pb)/liquid(Sn) diffusion couples were investigated under various static magnetic fields. Results show that the β-Sn crystals mainly reveal an irregular dendritic morphology without or with a relatively low static magnetic field(B0.3 T). When the magnetic field is increased to 0.5 T, the β-Sn dendrites close to the final stage of growth begin to show some directional character. With a further increase in the magnetic field to a higher level(0.8–5 T), the β-Sn dendrites have an enhanced directional growth character, but the dendrites show a certain deflection. As the magnetic field is increased to 12 T, the directional growth of the β-Sn dendrites in the center of the couple is severely destroyed. The mechanism of the directional growth of the β-Sn crystals and the deflection of the β-Sn crystals with the application of static magnetic field was tentatively discussed.