基于LabVIEW的超导磁体数据监测与分析系统

混合磁体是稳态强磁场装置中最具代表性的一个装置,由水冷磁体和超导磁体等部分组成,其中失超探测系统是该磁体安全运行的重要保障。针对前期超导磁体失超探测系统不能实现数据显示、存储与分析的问题,研制了超导磁体数据监测和分析系统。系统基于NI PXIe系列模块搭建,采用LabVIEW平台开发,汇聚超导磁体线圈的电压、电流、电阻信号,实现了超导磁体运行参数的采集、存储、显示、告警和分析功能。该系统成功投入运行,满足设计指标,为磁体装置的安全运行提供了保障。     

Genotoxic Effects of Superconducting Static Magnetic Fields （SMFs） on Wheat （Triticum aestivum） Pollen Mother Cells （PMCs）

The effects of superconducting static magnetic fields （SMFs） on the pollen mother cells （PMCs） of wheat were investigated in order to evaluate the possible genotoxic effect of such non-ionizing radiation. The seeds of wheat were exposed to static magnetic fields with either different magnetic flux densities （0, 1, 3, 5 and 7 Tesla） for 5 h or different durations （1, 3 and 5 h） at a magnetic flux density of 7 Tesla. The seeds were germinated at 23℃ after exposure and the seedlings were transplanted into the field. The PMCs from young wheat ears were taken and slides were made following the conventional method. The genotoxic effect was evaluated in terms of micronucleus （MN）, chromosomal bridge, lagging chromosome and fragments in PMCs. Although the exposed groups of a low field intensity （below 5 Tesla） showed no statistically significant difference in the aberration frequency compared with the unexposed control groups and sham exposed groups, a significant increase in the chromosomal bridge, lagging chromosome, triple-polar segregation or micronucleus was observed at a field strength of 5 Tesla or 7 Tesla, respectively. The analysis of dose-effect relationships indicated that the increased frequency of meiotic abnormal cells correlated with the flux density of the magnetic field and duration, but no linear relationship was observed. Such statistically significant differences indicated a potential genotoxic effect of high static magnetic fields above 5 T.     

YBa_2Cu_3O_(7-δ)外延薄膜中二维钉扎效

在几个恒定磁场中,测量了不同磁场取向下ＹＢａ２Ｃｕ３Ｏ７外延薄膜的电阻转变曲线。实验结果表明,由不同约化电阻判据确定的特征温度Ｔ＊、有效钉扎势Ｕ以及临界电流密度Ｊｃ均随着磁场与膜面的夹角增大而变化,并表现出相同的变化规律。在夹角小于７５范围内,本征钉扎机制起支配作用;而在９０附近,沿ｃ轴方向的二维缺陷等对磁通线的钉扎作用十分明显。     

超导交流应用测试系统及实验

介绍了作为超导交流应用测试系统的测量装置。由具有适合超导线材短样和小型超导线图测量、最大电流可达士20OA的交流电源、配套的计算机数据采集系统、低温杜瓦装置等组成。给出了对国产0．65mm的NbTi线材的一项实验结果。     

Bi2223/Ag带双饼线圈失超电压耦合补偿测试

为排除双饼线圈两端的自感电压对其失超信号的影响，把它降低到测量所允许的范围内，本文介绍双饼线圈外加补偿线圈的耦合测试原理和在此基础上制成的Ic的测试装置。分别对研制的9个高温超导双饼线圈的Ic进行测试，获得非常好的实验结果，为将9个双饼线圈组合成磁体提供了依据。