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基于特征光谱识别的光纤化学传感技术 被引量:3
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作者 庞全 《仪器仪表学报》 EI CAS CSCD 北大核心 2001年第6期588-591,共4页
本文针对目前光纤化学传感器普遍存在的提高选择性和灵敏度的困难 ,研究和建立了一种基于人工神经网络的特征光谱识别技术。将这种技术与传统的光纤传感技术相结合 ,有效的降低了传感器对化学识别器选择性和灵敏度的要求 ,提高了传感器... 本文针对目前光纤化学传感器普遍存在的提高选择性和灵敏度的困难 ,研究和建立了一种基于人工神经网络的特征光谱识别技术。将这种技术与传统的光纤传感技术相结合 ,有效的降低了传感器对化学识别器选择性和灵敏度的要求 ,提高了传感器的识别能力和检测范围 ,有助于光纤化学传感器的工程实现和实际应用。 展开更多
关键词 特征光谱识别 神经网络 光纤化学传感器
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拉曼光谱的16种多环芳烃(PAHs)特征振动光谱辨识 被引量:11
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作者 曾娅玲 姜龙 +1 位作者 蔡啸宇 李鱼 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2014年第11期2999-3004,共6页
借助密度泛函理论中B3LYP/6-311++G(d,p)方法对美国EPA优先控制污染物中的16种多环芳烃(PAHs):萘、苊烯、苊、芴、菲、蒽、荧蒽、芘、苯并[a]蒽、稠二萘、苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘、二苯并(a,h)蒽、二苯并[g,h,i]芘以及茚苯... 借助密度泛函理论中B3LYP/6-311++G(d,p)方法对美国EPA优先控制污染物中的16种多环芳烃(PAHs):萘、苊烯、苊、芴、菲、蒽、荧蒽、芘、苯并[a]蒽、稠二萘、苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘、二苯并(a,h)蒽、二苯并[g,h,i]芘以及茚苯(1,2,3-cd)芘进行结构优化,并计算拉曼光谱振动频率和去偏振度,在此基础上辨识多环芳烃的拉曼特征光谱。研究显示,16种PAHs的拉曼振动主要分布在3个频区:200~1 000cm-1(指纹区)、1 000~1 700和3 000~3 200cm-1(基团频率区),3个频区主要振动归属分别为环变形(ring def),碳碳伸缩(CCStr)、碳氢摇摆(CHw)及其耦合振动(CCStrCCw),碳氢伸缩(CHStr)。进一步分析显示,指纹区16种PAHs的去偏振度随苯环变形振动对称性增强而降低,在该频区去偏振度最小的频移处苯环呼吸振动的对称性最强,指纹区的峰强也在此处出现最大值。任意PAHs在指纹区的最强峰之间的波数差较大,在显微拉曼光谱的可分辨范围内,因而利用指纹区的去偏振度和最强峰可将16种PAHs逐一识别。烷烃、烯烃、炔烃、醇类和酚类、脂肪醚、芳基烷基醚、醛类、酮类、羧酸、酯类、胺类、腈类、酰胺类、酸酐、芳烃的振动频率和峰强分布不完全一致,利用PAHs与这几类物质拉曼频率和峰强分布的差异可以逐一排出干扰。 展开更多
关键词 多环芳烃 拉曼振动归属 拉曼特征光谱识别 指纹区 去偏振度
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基于苯溶剂化效应的多种邻苯二甲酸酯(PAEs)拉曼特征振动光谱辨识 被引量:4
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作者 邱尤丽 曾娅玲 +1 位作者 姜龙 李鱼 《发光学报》 EI CAS CSCD 北大核心 2015年第8期976-982,共7页
利用密度泛函与自洽反应场理论在B3LYP/6-311G(d)水平下对16种邻苯二甲酸酯(PAEs)进行结构优化,并计算气态环境及溶剂中PAEs的拉曼光谱振动频率和去偏振度。研究显示,16种PAEs拉曼振动归属为苯环变形、酯基振动、C—C伸缩、C—H摇摆、C... 利用密度泛函与自洽反应场理论在B3LYP/6-311G(d)水平下对16种邻苯二甲酸酯(PAEs)进行结构优化,并计算气态环境及溶剂中PAEs的拉曼光谱振动频率和去偏振度。研究显示,16种PAEs拉曼振动归属为苯环变形、酯基振动、C—C伸缩、C—H摇摆、C—H伸缩与耦合振动。其中酯基官能团出峰位置在1 700~1 780cm-1之间,拉曼峰较强,去偏振度较低(振动的对称性较强),可将酯基振动作为特征振动;但气态环境下仅12种PAEs拉曼峰之间的最小波数差大于显微拉曼光谱仪的检出限(0.2 cm-1),即利用酯基频区的去偏振度和拉曼峰不能完全辨识16种PAEs。溶剂化效应分析显示,溶剂苯对16种PAEs具有明显的溶剂化增强效应,16种PAEs拉曼峰之间最小波数差均增大到0.2 cm-1以上,且峰强增加了23%~183%,说明溶剂化效应下可利用酯基频区的去偏振度和拉曼峰辨识16种PAEs。本文的研究结果为PAEs拉曼光谱检测提供了理论依据。 展开更多
关键词 邻苯二甲酸酯 拉曼振动归属 拉曼特征光谱识别 溶剂化效应 去偏振度
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Feature extraction for target identification and image classification of OMIS hyperspectral image 被引量:7
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作者 DU Pei-jun TAN Kun SU Hong-jun 《Mining Science and Technology》 EI CAS 2009年第6期835-841,共7页
In order to combine feature extraction operations with specific hyperspectral remote sensing information processing objectives,two aspects of feature extraction were explored. Based on clustering and decision tree alg... In order to combine feature extraction operations with specific hyperspectral remote sensing information processing objectives,two aspects of feature extraction were explored. Based on clustering and decision tree algorithm,spectral absorption index (SAI),continuum-removal and derivative spectral analysis were employed to discover characterized spectral features of different targets,and decision trees for identifying a specific class and discriminating different classes were generated. By combining support vector machine (SVM) classifier with different feature extraction strategies including principal component analysis (PCA),minimum noise fraction (MNF),grouping PCA,and derivate spectral analysis,the performance of feature extraction approaches in classification was evaluated. The results show that feature extraction by PCA and derivate spectral analysis are effective to OMIS (operational modular imaging spectrometer) image classification using SVM,and SVM outperforms traditional SAM and MLC classifiers for OMIS data. 展开更多
关键词 hyperspectral remote sensing feature extraction decision tree SVM OMIS
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Study on the ultraviolet-visible spectral feature of tobacco leaves by pattern recognition
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作者 RUAN Chun-sheng XU Chang-liang +5 位作者 ZHANG Ge FAN Jing LI Yu-zhong WANG Xiao-xia FANG Li CHEN Sui-yun 《Journal of Life Sciences》 2009年第9期34-42,53,共10页
In order to differentiate regions, varieties, and parts of tobacco leaves, two pattern recognition methods through pattern classification modeling were developed based on the comprehensive information of ultraviolet-v... In order to differentiate regions, varieties, and parts of tobacco leaves, two pattern recognition methods through pattern classification modeling were developed based on the comprehensive information of ultraviolet-visible spectroscopy (UV-VIS) by employing one-way analysis of variance (ANOVA1) and wave range random combination (WRRC) technology from MATLAB. This proposed classification method has never been reported previously and the instrument and operation for this method is much more convenient and efficient than previous reported classification methods. The result of this paper demonstrated that the spectral features extracted by ANOVAI and WRRC methods could be used to differentiate tobacco leaves with different patterns. The ANOVAI method had a training recognition rate range of 75.00-87.50%,4 and a validation recognition rate range of 57.14-100%. The WRRC method had a training recognition rate range of 75.00-94.12% and a validation recognition rate range of 66.67-100%. The ANOVAI method is more convenient and efficient in model developing, while the WRRC method utilizes fewer model variables and is more robust. 展开更多
关键词 Nicotiana tabacum ultraviolet-visible spectroscopy (UV-VIS) pattern recognition spectral feature DIFFERENTIATION
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