不锈钢精密薄壁件外表面磁力研磨工艺研究

磁性研磨是一种利用磁场中的磁性磨料,对具有相对运动的工件表面进行光整加工的新技术。选择铝、镍、钴磁粉作为磁性磨料时,对奥氏体不锈钢精密薄壁件外表面具有良好的研磨作用。     

Imaging the domain pattern of the canted magnetization state in Co/Pt multilayer films

The exact magnetization pattern of magnetic films close to a spin-reorientation transition is difficult to analyze due to the intrinsically three-dimensional (3d) variation of the orientation of the local magnetization. We present a technique how this can be performed, based on the analysis of high quality 2d polarization maps from a single scanning electron microscope with polarization analysis (SEMPA) measurement with tilted sample. The key tool is the statistical distribution of all occurring polarization doublets, visualized in a 2d histogram plot. From the shape of the distribution the type of transition—canted-phase, or coexisting phases—can be inferred. For the canted-phase state, the canting angle can be accurately determined from geometrical considerations. With help of the histogram the image data can be analyzed and the three components of the magnetization can be calculated for most points of the image. For a Co/Pt multilayer film we found a cone state. The magnetization forms a complex pattern consisting of out-of-plane domains while the in-plane magnetization shows a maze pattern.     

Facile synthesis of nanocrystalline zinc ferrite via a self-propagating combustion method

Macroporous nanocrystalline zinc ferrite with single spinel-phase was prepared by a facile self-propagating combustion method using zinc nitrate, iron nitrate and glycine. The as-prepared ZnFe₂O₄ were characterized by X-ray diffraction (XRD) analysis, N₂ adsorption, scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and energy dispersive X-ray spectrum (EDS). The magnetic properties of the prepared ZnFe₂O₄ were also studied.     

汽轮机轴承烧瓦与轴颈的渗巴氏合金现象

简述轴承工作性质，巴氏合金应用与相组成的基本情况。论述汽轮机转子在两个电厂长期运行后，由于轴颈发生的不正常摩擦损伤，在大修改造中由无损检查、机械加工揭示出轴颈存在严重的渗巴氏合金现象，低熔点金属Sn、Sb与Cu向转子材料晶界的深层渗入最终导致了3根大型在投转子的严重开裂与报废。图11表2     

非平面对称磁场的空间展开及样条函数表述

为了研究带电粒子光学系统的光学特性,需要知道系统中磁场的空间分布。实际磁场往往不具有严格的平面对称性质,一些作者曾就这类磁场的空间展开做过不少工作。但他们的工作是在柱坐标系统中进行的,适用于诸如回旋加速器、双向聚焦磁分析器、环形磁β谱仪等一类装置的磁场分析。对于大型同位素电磁分离器(calutron)那样一类装置,其磁场分布需要     

High-field magnetic and transport critical current density of Sm-Ba-Cu-O: Agx superconductors at low temperature

Variation of magnetic critical current density (J _mc) and transport critical current density (J _tc) in high magnetic fields at liquid helium temperature were investigated on Sm-Ba-Cu-O: Ag _x (x=0.0, 0.2, 0.4, and 0.6) superconducting samples prepared by the coprecipitation technique.T _c and crystallographic parameters remain unaffected by Ag addition. However, bothJ _mc andJ _tc were found to increase on Ag addition. The volume pinning force (F _p) also increased with increase in Ag concentration, resulting in stronger flux line sheer. Microwave-induced d.c. voltage measurement shows a significant reduction of the total number of weak links between the superconducting grains with increasing concentration of Ag, which creates stronger pinning potentials between the boundary of the superconducting intergrains. Hence, the volume pinning force is greatly enhanced by Ag addition, leading to flux line lattice movement which is responsible for highJ _mc andJ _tc.     

极尖断面为折线的四极透镜磁性能研究

对传统双曲线极尖的四极透镜进行了磁性能分析。在此基础上，提出了极尖断面为折线的四极透镜结构。磁场的数值分析以及测量结果表明：该结构产生的场梯度均匀，且具有磁场集中、磁场梯度高、便于加工和安装的对称性控制等优点。该结构的四极透镜已用于ＣＹＣＩＡＥ－３０回旋加速器和ＨＩ－１３串列加速器束流输运线之中     

Crystal orientation of β-phase isotactic polypropylene induced by magnetic orientation of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide

Melt crystallization of isotactic polypropylene (iPP), containing crystallites of N,N′-dicyclohexyl-2,6-naphthalenedicarboxamide (DCNDCA) as a nucleating agent of the the β-phase iPP crystal, is carried out under a magnetic field (6 T) to obtain the alignment of the iPP crystal induced by magnetic alignment of DCNDCA. In a previous paper, DCNDCA was reported to undergo magnetic alignment in a liquid suspension. The obtained iPP sample exhibits alignment of the β-phase crystal with the c-axis aligned perpendicular to the magnetic field. The comparison of this alignment of iPP with the reported magnetic alignment of DCNDCA indicates that the β-phase crystal grows epitaxially on the DCNDCA crystal. The (330)_β plane of the iPP crystal lies on the bc-plane of the DCNDCA crystal in which the direction of the c-axis of the iPP coincides with the direction of the b-axis of the DCNDCA crystal.     

Continuous Separation of Inclusions from Aluminum Melt Flowing in a Circular Pipe using a High Frequency Magnetic Field

The continuous separation of inclusions from aluminum melt flowing in a circular pipe using a high frequency magneticfield was investigated both theoretically and experimentally The separation efficiency was calculated based on thetrajectory method and compared with experimental results. It is found that the separation efficiency is a functilnondimensional parameters t_i·d_p~2B_e~2/μ_fμ_eα~2 and α/δ.The effective way to improve the separation efficiency is to increasethe effective magnetic flux density and decrease the pipe radius. and the value of α/δ should be kept about 2 in orderto obtain the optimum separation efficiency.