【摘要】：太赫茲波是處在電磁波譜中紅外與微波之間的一個頻段。超快激光在近十幾年的發(fā)展為其產(chǎn)生提供了便利,因而推動了它發(fā)展,也使得太赫茲光譜技術(shù)成為國際學(xué)術(shù)界的前沿研究熱點。太赫茲波特有的低能性、穿透性和指紋譜性等優(yōu)點使其具有良好的應(yīng)用前景。如低能性可用于無損檢測,穿透性能用于安全檢查,指紋譜性能用來識別物質(zhì)的成分或種類。當(dāng)下生活中,許多安全問題與我們生活息息相關(guān),需要我們?yōu)橹�。例如每每觸及人們敏感神經(jīng)的食品安全問題中,有害添加劑、地溝油和假冒偽劣產(chǎn)品需要我們檢測出來;令人惶恐不安的反恐安全問題中,毒品、炸藥以及槍支道具等需要我們檢測出來;日漸突顯的環(huán)境問題中,大氣污染指數(shù)需要實時監(jiān)控。太赫茲波的優(yōu)良特性,使其在物質(zhì)檢測方面具有很大潛力。太赫茲時域光譜技術(shù)是目前太赫茲波應(yīng)用于物質(zhì)研究的主要技術(shù),它能獲得物質(zhì)在太赫茲波段的光學(xué)參數(shù),通過對光學(xué)參數(shù)的分析,可以對物質(zhì)的成分組成進行分析。本文基于太赫茲時域光譜技術(shù),獲得阿膠、鹿角膠、四種苯胺、奶粉和三聚氰胺的太赫茲光譜,對物質(zhì)定性鑒別和混合物定量分析進行研究,成功將模式識別技術(shù)用于物質(zhì)太赫茲光譜的分析中,并應(yīng)用化學(xué)計量方法-偏最小二乘法成功對混合物進行定量分析。本文主要內(nèi)容和工作創(chuàng)新如下:對本課題的研究背景進行闡述,說明了此項研究的目的。對太赫茲波產(chǎn)生以及探測機理和實驗中常用到的透射式時域光譜系統(tǒng)做了詳細(xì)介紹,并給出了從測得的光譜中提取所需光學(xué)參數(shù)的公式,詳細(xì)介紹了樣品的制備、測試過程及注意事項。在對物質(zhì)的定性分析中,先是介紹了進行模式識別前數(shù)據(jù)預(yù)處理的方法如噪聲濾除和特征提取,然后對物質(zhì)模式識別所用到的人工神經(jīng)網(wǎng)絡(luò)和支持向量機做了原理上的推導(dǎo)。在獲得阿膠和鹿角膠,對氯苯胺、對甲苯胺、對硝基苯胺和對甲氧基苯胺這兩組樣品的太赫茲光譜后,運用模式識別方法對其進行分析。實驗結(jié)果表明,通過模式識別方法分析所獲得的太赫茲吸收系數(shù)可成功對物質(zhì)進行分類識別。在對物質(zhì)的定量分析中,先是對定量分析中所用到的化學(xué)計量方法-偏最小二乘法做了充分研究,然后對不同混合比例三聚氰胺和奶粉混合物的太赫茲吸收系數(shù)譜進行研究,發(fā)現(xiàn)其中的線性關(guān)系,依據(jù)比爾-朗伯定律,結(jié)合PLS回歸建立三聚氰胺含量回歸模型。結(jié)果表明,太赫茲時域光譜技術(shù)能成功對混合物進行定量分析。
[Abstract]:Terahertz wave is a frequency band between infrared and microwave in the electromagnetic spectrum. The development of ultra-fast laser in recent years has provided convenience for its generation, so it has promoted its development, and terahertz spectroscopy has become a frontier research focus in the international academic community. The unique advantages of terahertz wave, such as low energy, penetration and fingerprint spectrum, make it have a good application prospect. If low energy can be used for nondestructive testing, penetration performance for safety inspection, fingerprint spectrum performance for identifying the composition or type of substances. In the present life, many security problems are closely related to our life, and we need to work hard for it. For example, in food safety problems that touch people's sensitive nerves, harmful additives, trench oil and fake and shoddy products need to be detected. Among the frightening counter-terrorism security problems, drugs, explosives and gun props need to be detected; in the increasingly prominent environmental problems, the air pollution index needs to be monitored in real time. The excellent characteristics of terahertz wave make it have great potential in material detection. Terahertz time domain spectroscopy is the main technology that terahertz wave is used in matter research at present. it can obtain the optical parameters of matter in terahertz band. Through the analysis of optical parameters, the composition of matter can be analyzed. Based on the terahertz time domain spectroscopy, the terahertz spectra of gum, antler gum, four kinds of Aniline, milk powder and melamine were obtained, and the qualitative identification and quantitative analysis of the mixture were studied. The pattern recognition technique was successfully applied to the analysis of terahertz spectra of substances, and the stoichiometric method-partial least square method was used to quantitatively analyze the mixture. The main contents and work innovation of this paper are as follows: the research background of this topic is described, and the purpose of this study is explained. The generation and detection mechanism of terahertz wave and the transmission time domain spectral system commonly used in experiments are introduced in detail, and the formula for extracting the required optical parameters from the measured spectrum is given, and the preparation of the sample is introduced in detail. Test process and matters needing attention. In the qualitative analysis of matter, the methods of data preprocessing before pattern recognition, such as noise filtering and feature extraction, are introduced, and then the artificial neural network and support vector machine used in material pattern recognition are deduced in principle. After obtaining terahertz spectra of gum and antler gum, p-chloranilide, p-toluidine, p-nitroanilide and p-methoxyphenylamine, the samples were analyzed by pattern recognition method. The experimental results show that the terahertz absorption coefficient obtained by pattern recognition method can successfully classify and recognize substances. In the quantitative analysis of substances, the partial least square method, which is the stoichiometric method used in the quantitative analysis, has been fully studied, and then the terahertz absorption coefficient spectra of the mixtures of different mixing ratios of melamine and milk powder have been studied. The linear relationship was found. According to Bill Lambert's law and PLS regression, the regression model of melamine content was established. The results show that terahertz time domain spectroscopy can successfully analyze the mixture.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：O441.4

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本文編號：2496409