大型Tokamak装置中环向场超导线圈的传热研究

分析了HT-7U超导Tokamak核聚变装置中环向场超导线圈上的涡流损耗热产生的机理和迫流式超临界氦对流换热等过程，特别针对等离子体快速破裂时，极短时间内在环向场磁体中所产生的较大的涡流损耗而引起的焦耳热，对环向场线圈盒与超导磁体之间的热传递过程加以研究。本文采用国际上通用的有限元分析软件ANSYS5.7进行计算，计算所得的结果较为乐观。     

永磁除铁装置表面最佳磁感应强度的实验确定方法

在设计永磁除铁装置时，一个关键问题就是吸附表面磁感应强度的确定。在保证吸净率最高的条件下，必须确定其吸附表面磁感应强度大小，以确保除铁装置处于最佳运行状态。本文在大量实验的基础上，给出了测定表面磁感应强度的最佳值方法。     

基于前馈补偿的永磁同步电机电流谐波抑制方法

为抑制永磁同步电机电流的谐波,提出了一种前馈补偿的方法。通过对电机dq轴电流的Fourier分析,研究电机dq轴电流谐波的频率组成及其产生原因。利用前馈补偿的方法,对不同频率的电流谐波分别进行补偿。通过自动搜寻算法,得到补偿电压的幅值和相位,对电机的不同运行状况进行在线补偿。在搭建的1.25kW的永磁同步电机系统上进行了实验,经前馈补偿后,dq轴电流的6、12次谐波降低了85%左右。     

加快江西省稀土永磁产业发展的思考

通过分析国内稀土永磁产业的发展历程,归纳了稀土产业发展的3个阶段,并指出该产业未来发展的4个趋势,从而提出加快发展江西省稀土永磁产业的6点建议。     

超导储能混合磁体的失超检测

针对超导储能混合磁体的特点,设计了一套用于超导储能混合磁体的失超检测与保护系统。系统采用数字失超捡测方法,利用高性能的数字采集卡NI-6224．快速可靠的检测到磁体失超;并通过卸能电阻可变的卸能回路实现磁体的失超保护,极大地加速了磁体电流的衰减．提高了移能效率．减小失超区的温升。     

An optimized magnet for magnetic refrigeration

A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halbach cylinder magnet design and dimensioning and segmenting this design in an optimum way followed by the construction of the actual magnet. The final design generates a peak value of 1.24 T, an average flux density of 0.9 T in a volume of 2 L using only 7.3 L of magnet, and has an average low flux density of 0.08 T also in a 2 L volume. The working point of all the permanent magnet blocks in the design is very close to the maximum energy density. The final design is characterized in terms of a performance parameter, and it is shown that it is one of the best performing magnet designs published for magnetic refrigeration.     

混沌状态下永磁同步发电机的故障诊断——LMI法研究

本文以永磁同步风力发电机为研究对象, 在两相同步旋转坐标系下建立了永磁同步发电机的数学模型. 应用时间尺度和线性仿射变换建立了系统混沌模型, 验证了系统在某些参数和工作条件下会出现混沌运动. 随后在考虑系统不确定性的情况下设计了故障观测器, 在系统发生故障时, 通过所设计的故障观测器能对混沌状态下永磁同步发电机的故障做出准确估计. 仿真结果表明基于线性矩阵不等式方法的故障观测器能够对系统故障做出快速准确的诊断. 关键词： 永磁同步发电机 混沌 非线性不确定系统 故障诊断     

Tunneling through two single molecular magnets in series arrangement junction in parallel/antiparallel situations

We investigate the spin-dependent tunneling transport in a heterostructure with two single molecular magnets (SMMs). The tunneling magnetoresistance (TMR) and negative differential conductance due to the strong resonant tunneling in the junction are demonstrated by the master equation approach. At low bias voltage, the device presents low/high resistant states with the initial states of the single molecular magnets parallel/antiparallel. Strong Coulomb repulsive interaction suppresses the current greatly in antiparallel situation. At high voltage, the middle system containing two SMMs tends to be non-polarized, and acts like ordinary quantum dots.     

Low-field nuclear magnetic resonance spectrometer for non-invasive monitoring of fluctuations in blood glucose in the human finger

A low-field nuclear magnetic resonance spectrometer for non-invasive monitoring of human finger blood glucose fluctuations was developed. Saline solution and blood serum samples with different glucose concentrations were first detected by the spectrometer and it has been found that there was a high-linear correlation between the glucose concentration and the transverse relaxation time. Then, the spectrometer was employed to noninvasively measure a finger from each of the several volunteers. The experiment results showed that the transverse relaxation time of the human finger increases with human blood glucose concentration. In conclusion, the human finger nuclear magnetic resonance spectrometer could be a potential tool to noninvasive monitoring of human body’s blood glucose fluctuations in the future.     

有机高分子磁体的分子设计

对有机高分子磁体的分子设计研究进行了综述,讨论了设计有机高分子磁体主要的4种理论模型,即Heiter London自旋交换模型、分子间电子转移模型、高自旋多重度模型和超级交换模型,并对这一领域的发展和应用进行了展望.