Nanoengineering of Flux Pinning Sites in High－Tc Superconductors

Volume pinning forces were determined for a variety of bulk high-Tc superconductors of the 123-type from magnetization measurements. By means of scaling of the pinning forces, the acting pinning mechanisms in various temperature ranges were identified. The Nd-based superconductors and some YBCO crystals exhibited a dominating pinning of the δTc-type (i.e., small, superconducting pinning sites). In contrast to this, the addition of insulating 211 particles provided pinning of the δl-type; providing effective pinning in the entire temperature range acting as a “background” pinning mechanism for the peak effect. Due to the small coherence lengths of the high-Tc compounds, effective pinning sites are defects or particles of nanometer size relative to ε^3. Integral magnetic measurements of the magnetization as a function of temperature in large applied magnetic fields (up to 7 T) revealed that practically all high-Tccompounds were spatially inhomogeneous, which could becaused by oxygen deficiency (YBCO), solid solutions of Nd/Ba (NdBCO and other light rare earth compounds), intergrowths (Bi-based superconductors), and doping by pair-breaking dopants like Zn, Pr. This implies that the superconducting sample consists of stronger and weaker superconducting areas, coupled together. In large applied fields, this coupling gets broken and the magnetization versus temperature curves revealed more than one superconducting transition. In contrast, irradiation experiments by neutrons, protons,and heavy-ions enabled the artificial introduction of very effective pinning sites into the high-Tc superconductors, thus creating a large variety of different observations using magnetic data. From all these observations, we construct a pinning diagram for bulk high-Tc superconductors explaining many featuresobserved in high-Tc samples.     

永磁非金属液体电磁泵磁场数值分析

将电磁泵体求解场域按二维平面场处理,考虑了外磁场对永磁体的磁化效应,用有限元法对永磁非金属液体电磁泵的磁场进行了数值分析,得到了该电磁泵气隙中的磁密曲线以及载流海水在气隙中流动所受到的电磁力.实验证明该数值分析的结果是准确的,这些数据为永磁非金属液体电磁泵的设计和应用提供了可靠依据,同时也说明了可用永磁体代替价格昂贵的超导磁体应用于非金属液体电磁泵的磁极设计.图7,参7.     

中频电磁场对连续铸造铝合金铸锭表面质量影响

研究了在冷坩埚式结晶器外施加中频电磁场对铝合金连续铸造铸锭表面质量的影响，通过测量结晶器内的磁场分布确定了铝合金电磁连铸的基本工艺参数．研究结果表明：采用在结晶器壁开缝的方法可以有效地提高结晶器内的磁感应强度．对本工艺，当开缝数在12—18的条件下，磁场分布基本均匀；施加中频电磁场可有效地消除偏析瘤，明显地改善连铸坯的表面质量．     

电磁场变换式的直接推导

利用等效替代方法和麦克斯韦方程组,可以不通过狭义相对论而直接导出非相对论情形下的电磁场变换式,从而给出一种求电场和磁场间关系的简捷途径.     

磁性物体探测的线性求解方法

利用磁偶极子磁场的逆变公式，推导出通过物体磁场及其人梯度表示的用于解决磁性探测等问题中的线性方程组，解决了以往在求解该问题过程中缺乏清晰的理论模型及计算误差较大问题。在计算机上所作的模拟计算表明该方法是成功的。     

空磁控靶溅射刻蚀的模拟研究

建立了磁控溅射单粒子模型，结合靶表面磁场的分布，用ＭｏｎｔｅＣａｒｌｏ研究了溅射气体粒子的运动规律，得到靶表面刻蚀的图形，发现靶中间环的刻蚀最强，这与实验结果和磁场的水平分量分布一致。     

磁场中的有效势能和相互作用能

本文讨论磁场中的有效势能和相互作用能,分析有效势能和一般势能——相互作用能的区别。     

磁场对固定化乳酸脱氨酶催化活性的影响

采用流通池光纤荧光光度法，对固定化乳酸脱氢酶（ＬＤＨ）在静磁场作用下的催化活性进行了探讨．发现在０．０８４～０．２３０Ｔ磁场作用下ＬＤＨ的催化活性明显降低，其降低值随磁场强度增强而增大，且与磁场作用的时间和ｐＨ值有关，而在２５～４０℃范围内，温度则无显著影响。     

各向异性磁介质中载流矩形线圈空间磁场

在给出的各向异性的毕奥－萨伐尔定律的基础上，求出载流矩形线圈在各向异性磁介质中的空间磁场，为研究磁各向异性的磁场提供了实例。     

安培力及其特点的分析

通过对安培力特点的分析，给出一种判断载流线回受安培力作用时线圈运动或形变总趋势的一般结论．