【作者】 李黎明；

【导师】 郑小林；

【作者基本信息】 重庆大学 ， 生物医学工程， 2013， 硕士

【摘要】 在生物医学磁弹性传感器研究中，虽然检测的具体目标多种多样，但其检测设备具有较高的通用性，其核心就是检测铁基非晶合金的共振特性的变化情况。因此设计一种操作简便、低成本的铁基非晶合金共振特性检测系统可以满足磁弹性生物医学传感器研究中对通用检测设备的需求。目前铁基非晶合金的共振特性检测方法中，时域振铃检测法应用于高粘度溶液的环境中时，信号幅值衰减较快，从而导致检测的精度较低；频域扫频-双线圈感应法存在线圈体积较大、结构复杂、接收线圈容易受到激励线圈的干扰等问题。而且大部分设备采用普通电压源的激励方式，存在因合金影响激励线圈的阻抗从而导致激励磁场不稳定的问题。针对这些问题本文设计了一种采用阻抗检测法的铁基非晶合金共振特性检测系统。在系统硬件方面，主要由微控制器单元、激励螺旋线圈、可编程直流偏置单元、可编程交流电流源激励单元、阻抗幅值检测单元、阻抗相位检测单元及RS232通信单元组成。在软件系统方面，编写微控制器相关程序实现系统工作参数的设置、自动扫描检测和数据传输功能。使用Metglas2826MB铁基非晶合金带材制作测试样片对搭建的检测系统进行了性能及功能测试，包括铁基非晶合金在空气、水中的共振特性观察、寻找最佳直流偏置电压实验、系统重复性实验以及铁基非晶合金对表面质量变化的响应测试实验。实验结果表明，系统能够对铁基非晶合金的共振特性进行准确的检测，并具有良好的稳定性和可重复性。测得铁基非晶合金的共振频率与其表面的质量变化情况基本成线性关系，符合理论预期。最后利用铁基非晶合金设计了凝血检测芯片，并进行了人体血液全血凝血检测和血浆凝血检测的初步实验和研究。实验结果表明，芯片在凝血过程中的响应幅值变化与凝血理论过程具有高度的相关性，能够从一定程度上反映出凝血的动态过程，且具有用血量少，成本低的优点。因此，使用铁基非晶合金进行凝血检测具有较高的可行性。更多还原

【Abstract】 In the study of magnetoelastic biomedical sensor, although there are a variety ofdetection goal for different objectives, the detecting system whose core is to detect theresonance characteristics of the Fe-based amorphous alloys is showing high generality.Design a low-cost detection system which is easy to operate for detecting resonancecharacteristics of Fe-based amorphous alloys, can meet the requirements for detectionequipments in the study of magnetoelastic biomedical sensors. Considering the currentdetecting methods of the Fe-based amorphous alloyss resonant characteristics, the timedomain ringing detection method has the problem that when applied in the highdamping force environment, such as the solution with high viscosity, the signalamplitude decreases rapidly, resulting in a low precision of detection; Frequencysweeping-dual coils method has some shortcoming such as the coil is large and thestructure of the coils is complex, and the receiving coil is easily interfaced by theexcitation coil. Furthermore, In traditional detection equipments, voltage source is usedto produce excitation signal, this bring a problem that the changes of the impedance ofexcitation coil will lead to instability of the magnetic field.Aiming to solve these problems, a detection system based on impedance detectionmethod for the resonance characteristic detection of Fe-based amorphous alloys wasdesigned. The system hardware was consisted of MCU, excitation coil, programmableDC bias unit, programmable AC current source excitation unit, impedance amplitudedetection unit, impedance phase detection unit and RS232communication unit. In thesoftware system, the programs of MCU were developed to perform parameters setting,auto scanning detection and data transmission functions.Performance and function experiments of detection system were performed usingFe-based amorphous alloys Metglas2828MB ribbons, including the experiments for theresonance characteristics detection of Fe-based amorphous alloys in air and in water, theexperiments for looking the best DC bias voltage, the system repeatability experimentsand the experiment for detecting the response of Fe-based amorphous alloys when themass of senor surface changed. Experimental results showed that resonantcharacteristics of Fe-based amorphous alloys can be accurately detected by this system,which had a good stability and reproducibility. There was a linear correlation betweenthe resonance frequency of Fe-based amorphous alloys and the mass of the surface, which was consistent with theoretical expectations.Finally, a test chip for coagulation detection based on Fe-based amorphous alloyswas designed. A preliminary experiment and study of human blood coagulationdetection and plasma coagulation detection was carried out by using this chip.Experimental results showed that the changing of resonance amplitude of the chip in thecoagulation process has a high degree of correlation with coagulation process in theory;it can reflect the dynamic process of blood coagulation to some degree. And in thismethod, a very small quantity of blood is required, and the cost is low. Therefore, thereis a high feasibility to complete coagulation detection using Fe-based amorphous alloys.更多还原