Research On Detection System Of Explosives Based On Molecular Imprinting Piezoelectric Sensor

With the efficient and rapid development of today’s society, there have been outstanding and huge changes on the aspects of economy, technology, culture and so on, but the unstable factors in society are also gradually increasing correspondingly. Nowadays more and more terrorism events can be heard in our society, which pose serious threat to world’s security and stability, as well as people’s lives and property. And among all terrorist incidents, the bombing is the most common one, whose arch-criminals are explosives. So now each country comprehensively strengthens the regulation of explosives, as well as significant investment of explosive detection devices with high-precision and high stability, which are designed to enhance the capacity of national security, as well as protection of people’s safety of lives and production. This thesis describes a kind of explosives detection system with high capacity of specificity detection, which takes the molecular imprinting technology as the principle and is based on molecularly imprinted polymer sensor. Production principle of the sensor is to combine molecularly imprinted polymer with piezoelectric quartz that is extremely sensitive to the quality.This thesis comprehensively introduces the explosive detection system from two aspects of the molecularly imprinted polymer sensor, and the hardware and software design of explosives detection system. The first part mainly introduces the principle of molecular imprinting technique, the working principle of different sensors and preparation of molecularly imprinted polymer. The most important thing is the verification of specificity and adsorption for molecularly imprinted polymers of some kinds of explosives (TNT, cyclonite and Sodium nitrate). The second part mainly introduces the explosive detection system from the aspects of the hardware circuit design and software programming. The explosives detection system is modularly designed according to characteristics of molecularly imprinted piezoelectric sensor, which includes an oscillation circuit module, a signal processing module, frequency difference measurement module of TDC-GP2, microcomputer control system of MSP430F249, and other modules.This subject researches and analyzes the sensor performance through a large number of experiments and validates the accuracy and stability of explosives detection systems. The sensor performance validation experiments show that the molecularly imprinted polymers produced in this research and its target molecule have good recognition performance and accurately detects explosives. The detection system conducts the experiment to detect the stability and accuracy of two signals’ frequency difference, which shows that, two input ports of measurement range1of TDC-GP2, Stopl and Stop2, separately measure the two input signals, and the measurement relative error in each channel is below0.05%; TDC-GP2measures the frequency difference between the two input signals, and the frequency difference measurement relative error is less than0.05%. All these results indicate that this system can accurately measure frequency difference signal.