高性能含镨快淬(Nd,Pr)12(FeCoZr)82B6粘结磁体的制备

采用过快淬加晶化退火处理的方法,研究了含有Pr的近正分快淬(Nd,Pr)12(FeCoZr)82B6粘结磁体制备工艺,粘结出的磁体磁性能为:Br=0.669T,Hci=811kA·m-1,Hcb=434kA·m-1,(BH)m=75kJ·m-3。合金快淬态的组成和显微结构、晶化退火温度、晶化退火时间直接影响磁体的磁性能,以24m·s-1速度快淬,并在655℃退火10min,可获得最佳磁性能。实验制备的粘结快淬(Nd,Pr)12(FeCeZr)82B6磁体(密度6 1g·cm-3)磁性能为:Br=0 669T,Hci=811kA·m-1,Hcb=434kA·m-1,(BH)m=75kJ·m-3     

Organic and Organometallic Molecular Magnetic Materials—Designer Magnets

Magnets composed of molecular species or polymers and prepared by relatively low-temperature organic synthetic methodologies are a focus of contemporary materials science research. The anticipated properties of such molecular-species-based magnetic materials, particularly in combination with other properties associated with molecules and polymers, may enable their use in future generations of electronic, magnetic, and/or photonic/photronic devices ranging from information storage and magnetic imaging to static and low-frequency magnetic shielding. A tutorial of typical magnetic behavior of molecular materials is presented. The three distinct models (intramolecular spin coupling through orthogonal orbitals in the same spatial region within a molecule/ion, intermolecular spin coupling through pairwise “configuration interaction” between spin-containing moieties, and dipole—dipole, through-space interactions) which enable the design of new molecular-based magnetic materials are discussed. To achieve the required spin couplings for bulk ferro- or ferrimagnetic behavior it is crucial to prepare materials with the necessary primary, secondary, and tertiary structures akin to proteins. Selected results from the worldwide effort aimed at preparing molecular-based magnetic materials by these mechanisms are described. Some organometallic solids comprised of linear chains of alternating metallocenium donors (D) and cyanocarbon acceptors (A) that is, …?D^?+ A^?? D^?+ A^??…?, exhibit cooperative magnetic phenomena. Bulk ferromagnetic behavior was first observed below the critical (Curie) temperature T_c of 4.8 K for [Fe^III(C₅Me₅)₂]^?+ [TCNE]^?? (Me = methyl; TCNE = tetracyanoethylene). Replacement of Fe^III with Mn^III leads to a ferromagnet with a T_c of 8.8 K in agreement with mean-field models developed for this class of materials. Replacement with Cr^III, however, leads to a ferromagnet with a T_c lowered to 3.65 K which is at variance with this model. Extension to the reaction of a vanadium(o) complex with TCNE leads to the isolation of a magnet with a T_c ≈ 400 K, which exceeds the thermal decomposition temperature of the material. This demonstrates that a magnetic material with a T_c substantially above room temperature is achievable in a molecule/organic/polymeric material. Finally, a new class of one-dimensional ferrimagnetic materials based on metalloporphins is discussed.     

Ba2Ca2Cu3Ox Precursor Effects on Synthesis of (Hg,Pb)Ba2Ca2Cu3O8+δ Superconductor

The influence of Ba₂Ca₂Cu₃O_x precursor on the synthesis and properties of (Hg,Pb)Ba₂Ca₂Cu₃O_8+δ has been examined. Fine homogeneous Hg-free precursor powder of Ba₂Ca₂Cu₃O_x of desirable phase composition was prepared by sol-gel method using EDTA acid as a complexing agent. A reproducible superconducting sample of Hg_0.8Pb_0.2Ba₂Ca₂Cu₃O_8+δ with fine-grained, dense microstructure, composed predominantly of (Hg,Pb)-1223 phase and with advantageous magnetic properties, was synthesized by high pressure crystallization in mercury environment of well-calcined Ba₂Ca₂Cu₃O_x precursor. This revised version was published online in July 2006 with corrections to the Cover Date.     

HTS块材与磁场间相互作用估算方法研究

HTS块材电磁机构日趋复杂，为了实现系统结构和电磁设计的优化需要建立一种简单可靠的方法来估算系统内部的相互作用．描述HTS磁学特性通常采用热激活磁通跳跃、磁通流动等系列模型，用其描述相互作用各有优缺点．为此，我们实验测试了HTS块材与永磁间相互作用随空间相对位置变化．并基于HTS完全抗磁性和临界态模型构造的B（H）曲线进行模拟仿真，通过与实验结果的比较．力求寻找一种方便可行、较为准确及可靠的HTS块材与磁场间相互作用估算方法．     

超导薄膜表面电阻测试方法及误差分析

本文介绍一种蓝宝石加载单端短路谐振腔测量高温超导薄膜的方法，并对测量误差进行了较详细的分析．造成测量误差的主要因素有三个：系统无载品质因数Q0的测量误差，超导薄膜以外损耗品质因数Qother的实验误差，以及在谐振腔内超导薄膜的几何参数G的计算误差．大量的实验结果表明，本方法操作简便，重复性好，测量精度高，相对测量误差不超过10％．     

分形子动力学及分形子对固体输运性质的影响

综述了逾渗系统的统计分形性质、逾渗网络的动力学、分形子概念的引入及其特殊的态密度 ,色散关系和超局域的性质、分形子存在的实验证据以及研究分形子的意义 .讨论了分形子 (振动分形子或磁分形子 )对金属玻璃中的类近藤效应 ,并对稀释磁体中电输运、半导体中激子弛豫动力学、分形结构超导体的转变温度、正常态电阻温度关系及分形子超局域化的实验证据等问题进行了研究 .     

应用曲面镜成像原理仿真高温超导体磁悬浮力

文章首次探讨了应用曲面镜成像原理 ,对高温超导体悬浮力进行仿真计算 ,并且比较了实验数据与计算结果 ,结果表明了此方法的有效性。文章还讨论了此方法今后的工作方向。     

Precise study of the first deflecting magnet of "Rhodotron" (TT200) using transfer matrices and ANSYS11

The beam trajectory in the first deflecting magnet of "Rhodotron" TT200 has been analyzed precisely by both optical and simulation methods.We found discrepancies between these two methods at the order of (10~(-3)) for the slit distance and deflecting radius and at the order of (10~(-4)) for the magnetic flux density.The main goal of the paper is beam focusing, considering the angular and momentum dispersion of the particles for the magnet designed by ANSYS.     

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根据ITER电流引线的要求,设计和试验了分别由全铍铜(Be2%Cu)、全不锈钢(SS)和二元金属(BeCu/SS)三种不同类型分流器制作的68kA电流引线的1/90试件。研究了超导段各组件的性能,详细讨论了失冷故障实验结果。结果表明,对比全铍铜和全不锈钢分流器,二元分流器制作的超导模件更能够提高安全性以及减小冷端漏热,满足ITER高安全性和低热负荷的要求。