FePt颗粒膜反磁化机制

构造了FePt:Au有序纳米颗粒膜的微结构模型,利用微磁学模拟的方法研究了一系列不同Au含量的FePt:Au颗粒膜的磁学性质.对比实验数据,分析反磁化过程可知:当反映Au含量的交换作用比例系数β>0.4时,FePt:Au颗粒膜的矫顽力随β减小而增大,但增幅较小,磁化反转为一致反转;当β<0.3时,随β的减小矫顽力迅速增大,磁化反转一致性降低.分析指出,当FePt磁性颗粒之间间距约为3~4nm时,颗粒间的交换相互作用可以近似为零,磁化反转为非一致反转.     

尾矿铁回收技术的研究与开发

以铁矿企业的尾矿为对象,以微磁学理论为基础,利用龙窑烧砖技术系统地模拟研究了高梯度磁选机回收含铁的强磁( Fe3O4)、弱磁(Fe2O3、FeCO3)矿物.结果表明:利用尾矿还原砖坯的传热性、龙窑内焙烧温度和时间控制、还原焙烧后的降温技术这三个关键环节,通过焙烧将弱磁性矿物转化为强磁性矿物,再经过磨矿磁选工艺,能够提取合格的铁精粉.     

轻稀土镧取代M型钡铁氧体超微粉末的合成与表征

利用溶胶-凝胶自蔓延高温合成法制备了稀土镧掺杂钡铁氧体BaLaxFe12-xO19超微粉末。讨论了起始溶液pH值、柠檬酸配比、煅烧温度等对粉末性能参数的影响。用X射线衍射仪、扫描电子显微镜和振动样品磁强计等对粉末的结构、形貌和磁学性能进行了研究。     

第二届全国生物磁学会议

第二届全国生物磁学会议1987年7月11日至15日在吉林市举行。它是由中国电子学会应用磁学学会、中国稀土学会、中华传统医学仪器学会生物磁学研究会、中国生物物理学会、中国畜牧兽医学会、北京钢铁学院联合举办的。这次会议的论文集共收录了150篇论文,其中综述4篇,磁在医学上的应用及生物磁学的研究83篇,生物磁学实验38     

环境磁学对重金属污染监测的研究进展

基于目前环境磁学对重金属污染监测的研究,首先介绍了地表重金属的主要来源,其次阐述了环境磁学的发展及其监测重金属污染的理论基础,最后从三个方面探讨了土壤和灰尘中重金属污染的磁学监测的研究进展,为重金属污染治理和环境修复提供了土壤环境管理新手段。     

Fe3O4纳米级超微粉末的制备试验

分析了讨论了以共沉淀制备Ｆｅ３Ｏ４纳米级超微粉末时，不同反应条件对产物粒径与磁学性能的影响，确定了较为合适的工艺参数，所制备的Ｆｅ３Ｏ４超微粉末，粒径分布均匀，平均粒径约为１１．８ｎｍ，比饱和磁化强度达７１．６ｃｍｕ／ｇ。     

Sm-Co/α-Fe/Sm-Co周期多层膜的微磁学模拟

以Sm-Co/α-Fe/Sm-Co周期多层膜体系为对象,微磁学理论为基础,运用OOMMF软件,采用三维动力学模型系统地模拟研究了该体系的磁性能与磁层厚度和体系层数的关系。结果表明:在所研究的磁层厚度范围内,当固定体系厚度不变和固定体系层数不变时,随着磁层厚度的增加,体系的剩磁和最大磁能积均逐渐减小;硬磁层的磁化反转形式不仅与软磁层的尺寸有关,而且与硬磁层本身的厚度也有一定的关系,也就是说,软磁层的临界尺寸与硬磁层的厚度也有关;体系的层数和厚度对体系的磁性能也有着不可忽略的影响。     

双层复合永磁薄膜磁性能的模拟研究

利用微磁学理论模拟计算了Nd2Fe14B／α-Fe双层复合永磁薄膜的磁滞回线,并对双层膜体系的剩磁、矫顽力与软磁层厚度的关系进行了研究。结果显示,软磁层厚度小于临近尺寸时,磁滞回线为矩形,双层膜完全耦合;软磁层厚度与磁性能的关系表明,随着软磁层厚度的增加,剩磁先增大后减小,而矫顽力单调下降。     

数值模拟工艺参数对氧化铝陶瓷微齿轮注射成形影响

微注射成形是微系统零件大规模生产的关键技术。通过ANSYS-CFX软件对氧化铝陶瓷微齿轮的注射成形充模过程进行了数值模拟,并通过试验对模拟的结果进行验证。研究表明,模拟结果与试验结果基本符合。注射速度和模具温度为氧化铝陶瓷微齿轮注射成形的关键工艺参数,注射温度对其影响不明显。     

沉积贵金属载体薄膜催化剂的计算机模拟研究

贵金属载体薄膜催化剂由于高效催化性及特殊的选择性而获得广泛应用,薄膜技术以及计算机模拟辅助设计日益成为其制备的新技术。文章评述了其制备技术的特性以及沉积机理的计算机模拟模型,并展示了其沉积过程的计算机模拟结果。     

Effect of heterogeneous microstructure on magnetization reversal mechanism of hot-deformed Nd-Fe-B magnets

The hot-deformed(HD) Nd-Fe-B magnets show heterogeneous microstructure composed of coarse and fine grain regions. It is significant to fully understand the influence of this complex microstructure on the magnetization reversal process which can give the guidance for the enhancement of the magnetic properties. In this paper, the heterogeneous microstructure of the(HD) Nd-Fe-B magnets were characterized from the morphology, size, macro-texture and micro-structure. In addition, the magnetization reversal process of the HD Nd-Fe-B magnets was systematically analyzed by magnetic measurement, insitu domain evolution observation and micromagnetic simulation. The results indicate that the HD NdFe-B magnets mainly consist of fine grain regions(FGRs) and coarse grain regions(CGRs). The FGRs show plate-like grains with fine grain size and strong c-axis texture, while the CGRs show equiaxial grains with large grain size and weak c-axis texture. In particular, it is worth noting that the texture in homogeneity exists not only between FGRs and CGRs, but also inside both the FGRs and CGRs. The dominant coercivity mechanism of the HD Nd-Fe-B magnets is domain wall pinning. Also, the experimental analysis shows that the reverse domain is formed and expanded in the CGRs at low reverse applied field, while the reverse domain occurs in the FGRs at higher reverse applied field. The micromagnetic simulation results also confirm the above magnetization reversal process. In addition, micromagnetic simulation results also show that the orientation of the grains also affects the pinning strength, besides the grain size.     

Purification of characterization of soybean allergen Gly m Bd 28K

The three-dimensional (3D) morphology of trabecular bone is frequently quantified using computer programs. However, there are no standardized implementations of morphology programs and many variations are possible. Even though programs may use the same basic method, results can be significantly different because of differences in implementation. Morphology data from different laboratories therefore may not be comparable. The method of directed secants, with parallel plate assumptions, is commonly used to quantify 3D morphology. We examined the effect of several variations in the implementation of this method on measurements of trabecular plate number (Tb.N), trabecular thickness, and trabecular spacing. Three-dimensional micromagnetic resonance images of 10 bovine trabecular bone specimens were analyzed using several variations of the directed secant method. An analysis of covariance with repeated measures suggested that variations in the algorithm used to count test line intersections, variations in the criteria used to classify a test coordinate as bone or marrow, and variations in the number of test grid rotations had significant effects on Tb.N (p < 0.0001). The largest difference in Tb.N (52%) was due to the method used to count test line intersections with the bone-marrow interface. Variations in the classification algorithm and variations in the number of test line grid rotations resulted in a 6% difference in Tb.N. The spacing of the test line grids did not affect Tb.N (p = 0.28), and all differences were independent of volume fraction (p = 0.67). These data show that there can be significant differences in trabecular bone morphology measurements due only to the method used for the measurements. To facilitate comparisons between laboratories, we have made validated computer programs to measure trabecular bone morphology available over the Internet.     

充填环管试验计算机仿真模型的探讨

充填环管试验是采用充填工艺（干式充填除外）的矿山设计前进行的一项必要工作,旨在获得充填工艺流程的流体流变参数。作为设计的依据。但充填环管试验要耗费较长的时间、大量的资金以及人力物力。通过对充填环管试验进行计算机仿真,可以获得充填料浆的流体流变参数。替代或部分替代充填环管试验,具有重要的现实意义。文中针对尾砂料浆充填环管试验计算机仿真模型的建立,提出了一个总的框架,给出了建立仿真模型的思路、数学模型。     

通用硬盘仿真技术的设计与实现

随着硬盘技术的不断发展,一些早期的计算机系统对目前大容量、高速度的硬盘存在着不能识别的问题,硬盘仿真代用则相当必要和迫切.文章在简要介绍硬盘的基本构造、接口类型及工作原理的基础上,重点论述了通用硬盘仿真专用硬盘技术的设计、实现方案,并简要描述了在宝钢实际应用后所取得的效果.     

Computer Simulation of Effect of Intergrain Exchange Interaction on Magnetic Properties of Nanocomposite Magnets

Nanocompositemagnetsareoneofcandidatesformagnetsinthenextgeneration .Inananocompositemagnet,theexistenceofmagneticallysoftgrainswithahighsaturationmagnetizationenhancestherema nence,andconsequentlyahigh (BH ) max valueisachieved[1] .Asthemagnetizationinthesoftgrainsispreventedfromtheirreversalbytheintergrainex changeinteractionbetweensoftandhardgrains ,theintergrainexchangeinteractionplaysanimportantroleindeterminingmagneticproperties .Therefore ,itscontrolisconsideredtobeakeytechnologyforobt…     

Research on Computer Simulation System of Stretch Reducing Mill for Tube

Ｓｔｒｅｔｃｈｒｅｄｕｃｉｎｇｐｒｏｃｅｓｓｉｓｏｎｅｏｆｍａｉｎｐｒｏｄｕｃ ｔｉｏｎｍｏｄｅｓｆｏｒｈｏｔ ｒｏｌｌｉｎｇｓｔｅｅｌｔｕｂｅｓ .Ｂｏｔｈｄｉａｍｅｔｅｒａｎｄｗａｌｌｔｈｉｃｋｎｅｓｓｃａｎｂｅｃｏｎｔｒｏｌｌｅｄｏｎｓｔｒｅｔｃｈｒｅ ｄｕｃｉｎｇｍｉｌｌ (ＳＲＭ ) .Ｔｈｅｍｅｔｈｏｄｆｏｒｔｕｂｅｐｒｏｄｕｃ ｔｉｏｎｃａｎｏｂｔａｉｎｔｈｅｌａｒｇｅｓｔｄｉａｍｅｔｅｒｒｅｄｕｃｔｉｏｎｏｎｃｏｎｄｉｔｉｏｎｔｈａｔｔｈｅｗａｌｌｏｆｔｕｂｅｄｏｅｓｎ’ｔｂｅｃｏｍｅｐｏｌ…     

Micromagnetic Analysis on Demagnetization Process of Single-Phase Nanocrystalline Permanent Magnets with Different Degrees of Orientation

A three-dimentional finite element micromagnetic algorithm was developed to study the magnetization reversal of Pr2Fe14B single-phase nanocrystalline permanent magnets. A single-phase nanocrystalline Pr2Fe14B magnets composed of 216 irregular shaped grains was built. The magnetic hysteresis loops were simulated by micromagnetic finite element method. The contribution of intergrain exchange coupling ment degree （IGEC） to remanence enhancement is considered related to the alignin oriented magnets, and decreased with improved grain alignment. For the magnets with perfectly crystallo- graphic alignment of grains, the contribution of IGEC to remanence enhancement is nearly zero. The shape of demagnetization curve is not only dependent on grain alignment degree but also on the strength of IGEC in magnets.