Design Of A Detecting System For Resonance Characteristics Of Fe-based Amorphous Alloys And A Preliminary Study About Its Application In Blood Coagulation Detection

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.