低温生物介电谱测试系统的研制

【作者】 刘海洋；

【导师】 陈照章；

【作者基本信息】 江苏大学 ， 控制理论与控制工程， 2006， 硕士

【摘要】 本课题来源于国家自然科学基金资助项目“电磁场对低温下生物生态影响的机理研究”。在细胞／组织／溶液低温保存中，“胞内冰”和“胞外冰”是导致其低温损伤的直接原因。该项目思路是应用电磁场来抑制细胞／组织／溶液冷冻过程中产生的冰晶，最终寻求一种新的生物体低温保存方法。在该项目的研究中，需要一套能实时监测并记录生物电介质在冷冻过程中由极化和相变引起的宏观量的变化的装置，以用来研究电磁场和温度变化对其的影响。由于介电谱方法能够对目标体系进行非破坏连续监测，了解体系有关动力学、结构特征和电的性质，在物理、化学、生物学等研究中均发挥着很大的作用。低温生物介电谱测试系统就是记录生物电介质介电（温）谱的一种装置。 论文介绍了低温生物介电谱测试系统的设计与研制过程，该系统应用了频域法中的等效原理。在本系统的硬件设计过程中，针对高频（1MHz）正弦信号峰值的测量，提出了以有效值测量代替峰值测量的方法，因为它们之间有着固定的2^1/2倍关系，并使用真有效值—直流转换芯片AD536A将之实现；针对频率高达1MHz的周期方波的占空比难以测量这一难题，提出并实现了以方波的直流分量与方波的高电平峰值之比代替占空比的方法，并用低通滤波器将之实现。本测试系统基于数据采集卡，软件编程使用的是VB6.0语言，并在其中调用一个能利用MATLAB的功能函数来进行矩阵计算、绘图显示的COM组件MatrixVB。最后，在程序的配合下，系统可以实时的显示电介质的介电（温）谱变化曲线。 本系统的成功研制，为低温生物介电谱的研究以及外界电场、磁场对生物电介质的影响等研究提供了有力的工具。更多还原

【Abstract】 This project stems from the project the research of mechanism of effect of the magnetic field on the living tissues in hypothermia, which is funded by National Natural Science Foundation of China （NSFC）. Ice formation inside or outside cells has been proposed to be a factor causing cryoinjury to cells or tissues or solution during cryopreservation. The approach of studying of the project funded by NSFC is to reduce or eliminate the ice formation in cells or tissues or solution during cryopreservation by inflicting magnetic field on them. So, we can find a new method of cryopreservation of the living tissues. In the studying of the project funded by NSFC,we need a system that can be used to detect and record change of macro-physical quantity of living tissues in cryopreservation,so as to study the effect of magnetic field and temperature on them. The method of studying the dielectric spectrum,for it can be used to detect object system continuously and nondestructively and to study its dynamic character, structural feature and electrical feature, plays a very important role in physics, chemistry and biology. The measuring system for cryobiological dielectric spectrum is indeed a instrument which can be used to calculate and record the dielectric coefficient and the dielectric spectrum of the bio-dielectric.In this paper, we have developed a fast measuring system for cryobiological dielectric spectrum（CDS）.The system is based on the theory of equivalent in frequency domain in dielectric spectrometer. To test the peak value of 1MHz sine signal, we use AD536A—RMS to DC converter—to test its RMS, which is multipliedby 2^1/2 to get its peak value. Since the direct current of periodic phase is direct ratio to its phase width, we test the direct current of 1MHz periodic phase by active low pass filter to get the 1MHz periodic phase’s phase width. This system is based on data acquisition card, and VB6.0 is used as a program language.MatrixVB—a COM component is referenced in VB6.0, which is used to calculate by matrix and draw curve. At last, this system can draw real-time curve of electric spectrum dynamically with the help of the program.This system will afford a powerful instrument for the studying in the field of cryobiological dielectric spectrum and effect of outer electric field or magnetic field on cryobiological dielectric.更多还原