生物体低温保存用低频磁场发生装置的研制与应用试验

为了研究在低降温速率条件下，低频磁场对基本生物溶液相变过程冰晶形成的影响，运用开关电容技术研制了低频旋转磁场发生装置。该装置由振荡器、开关电容、二阶跟踪系统、数字开关系统、功放电路及亥姆霍兹线圈组等部分组成，可以产生频率、强度连续可调的旋转磁场。在控制0.9% KMnO₄溶液降温速率的条件下，将该装置产生的低频旋转磁场作用于该溶液。试验结果表明，低频旋转磁场对该溶液相变过程中冰晶的形成有显著影响，冰晶的大小随磁场频率的增加而变小。这对低降温速率下食品及生物组织的低温无损保存具有重大意义。

Development and applied experiment of low-frequency magnetic field generator used for organism cryopreservation

To study the effect of low-frequency magnetic field on the solution ice crystal formation process under the condition of slow temperature-dropping rate, a device to produce alternated magnetic field was designed by using switching capacitor. This device, which is composed of oscillator, switching capacitor, second-order tracking system, digital switching system, power-amplifier circuit and Helmholtz coils, can produce rotating magnetic field whose frequency and strength can be adjusted continuously. The experimental results of 0.9% KMnO₄ solution with a slow temperature-dropping rate show that low-frequency rotating magnetic field markedly affects the ice crystal formation process and the size of ice crystal lessens with the increase of magnetic field frequency. This preliminary study indicates that low frequency crystal magnetic field is significant in organism cryopreservation.