Identify Terahertz Spectrum For Traditional Chinese Medicine&Drug And Its Applications

In recent years,with terahertz technology getting more and more attention,THz-TDS technology has been applied to various fields of material testing.Because there are many types of samples,it often appears all sorts of problems during the actual detection.The purpose of this paper is to solve multicomponent substance problems arising from the terahertz spectrum detection and its practical application devices.Firstly introduce the typical terahertz time-domain spectroscopy system and the method to process its signal data.Design the experiment to study traditional Chinese medicine samples without characteristic absorption peak and drug with obvious characteristic absorption peak.Put forward four kinds of spectral matching algorithm for similarity calculation of multicomponent samples absorption coefficient.The main contents of the thesis are as follows:1.This paper introduces the transmission-type terahertz time-domain spectroscopy system and the derivation process of the material parameters.The effect of the echo signal in terahertz time-domain pulse signal on the frequency-domain signal is analyzed,this paper expounds the necessity to remove the echo signal in time-domain signal from the formula derivation and data processing result contrast,effectively reduce the noise caused by the improper time domain signal processing.2.Caulis spatholobi and its easy mixed goods caulis sargentodoxae were tested.The tiny differences of the absorption coefficient between caulis sargentodoxae and caulis spatholobi emerged when we got the second order differential data.Introduce four kinds of spectral matching algorithm to calculate the similarity of them.From the classification results,spectral angle algorithm get the best effect,the recognition accuracy reaches 95%.3.The terahertz spectroscopy of eleven standard drugs were investigated,the result was relatively consistent when compared with the report in the literature within the scope of the instrument error.Two common samples are tested,Analyze the differences between the sample tested and the standard sample,finally successful identified the drug samples.Tested different optical rotation of methamphetamine,analyzed their different characteristics of the terahertz spectrum.Through the standard and common sample testing,Lying the foundation for further to find the resource of the drug by the THz-TDS technology.4.In order to test drug,We designed a specimen holder.Drug is extremely special,its detection strictly following the management measures.In this paper,samples were tested in polyethylene plastic bag which were sealed.In order to adapt to this kind of detection method,the specimen holder designed in this paper can also apply to direction test and sealing bag samples of detection.We designed a program which is easy to use for the terahertz spectrum data processing.The program is convenient to calculate and display terahertz absorption coefficient of the sample.