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直接正交校正用于牛奶成分近红外光谱分析 总被引:2,自引:0,他引:2
介绍采用近红外光谱分析方法快速检测牛奶主要成分含量的测量原理,探讨研究直接正交(DO)校正的基本方法.利用牛奶成分近红外光谱测量系统分别采集牛奶样品和葡萄糖白蛋白两成分溶液样品的近红外光谱,采用DO法进行光谱数据预处理,并采用偏最小二乘(PLS)法分别建立其相应的数学模型.实验及数据处理结果表明:经DO法预处理后,滤除了原始光谱中的部分噪声信息,但保留了原始光谱中的主要信息.PLS校正模型采纳的最佳因子数随着DO因子的依次滤除相应减少.牛奶中脂肪和蛋白质校正模型在原始光谱分别被滤除3和4个主成分时达到性能最佳,校正标准偏差SEC分别为0.3204和0.2727,预测标准偏差SEP为0.7316和0.4460,两成分溶液样品中白蛋白和葡萄糖校正模型在原始光谱被滤除1个因子时达到性能最佳.校正标准偏差SEC分别为0.2513和0.2780,预测标准偏差SEP为0.5169和0.7870,单位(g/dL),与DO法预处理之前的PLS模型相比,预测标准偏差相应降低,采纳的主成分数减少,模型得到简化. 相似文献
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利用近红外透反射光谱技术,研究短波近红外光谱(780~1100nm)无损检测蔗糖溶液的可行性,并通过主成分回归(PCR)和偏最小二乘(PLS)方法建立了蔗糖溶液的近红外定量分析模型。采用Savitzky-Golay卷积平滑(5点)和多元散射校正(MSC)进行预处理,并且对预处理后的数据进行建模分析。PCR定量分析的结果:主成分数PC=7,交互验证相关系数RCV=0.957335,交互验证的校正标准偏差RMSECV=0.015859;PLS定量分析结果:主成分数PC=4,交互验证相关系数RCV=0.975789,交互验证的校正标准偏差RMSECV=0.012251。分别用PCR和PLS的校正模型对预测集样本进行预测,两种模型的预测标准偏差RMSEP分别为0.0127,0.0118。二者均对高浓度蔗糖溶液的预测结果比较理想,而且在PLS模型下,77%以上的样本相对误差在10%以下,较PCR模型的高。综合结果,PLS所建立的模型简单,而且精度很高,所以,基于短波近红外光谱的蔗糖浓度的快速无损检测是可行的。 相似文献
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利用波长1064 nm的Nd∶YAG脉冲激光器获取国家标准土壤中铅元素的诱导击穿等离子体,并用八通道光纤光谱仪采集了样品等离子体光谱。应用多种光谱预处理方法对光谱进行信息提取和分析,比较了光谱的预处理方法对偏最小二乘(PLS)模型定量预测能力的影响。结果表明,采用9点光谱平滑处理和多元散射校正(MSC)预处理的模型质量较好,校正集和预测集的相关系数R分别为0.9981和0.9948,交互验证均方根误差(RMSECV)和预测均方根误差(RMSEP)分别为12和17;元素Pb浓度分析测量的结果与标准值的相对偏差在10.5%以内,实验表明LIBS结合PLS建模能满足土壤中微量重金属快速检测的要求。 相似文献
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基于STM的三维荧光导数光谱法检测食品中黄曲霉素 总被引:1,自引:1,他引:0
基于支持张量机(STM)的三维荧光导数光谱定量分析方法,检测了食品中黄曲霉素。在计算三维荧光导数光谱时,将常规的、只适用于向量光谱数据的Savitzky-Golay方法扩展到由二阶张量描述的三维荧光光谱中。同时,应用了STM方法建立校正模型,对白酒和牛奶中的黄曲霉素进行了检测。在对白酒中的黄曲霉素检测中,复相关系数(CC)和预测误差均方根(RMSEP)分别为0.952 3和14.847 5,与常规的偏最小二乘(PLS)和支持向量机(SVM)方法相比,CC分别提高了2.40%和2.34%,RMSEP分别降低了8.92%和4.36%。在对牛奶中的黄曲霉素检测中,CC和RMSEP分别为0.996 5和5.448 9,与PLS和SVM的方法相比,RMSEP分别提高了0.40%和0.30%,RMSEP分别降低了18.31%和17.18%。检测结果表明,基于STM方法建立的校正模型要优于传统的SVM方法和PLS方法。 相似文献
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为解决近红外光谱快速检测乳品成分及含量时光谱数据的预处理问题,提出一种基于直方图分层映射技术的近红外光谱主成分得分重置(SR)预处理方法。以葡萄糖氯化钠水溶液三组分样品中的葡萄糖含量、鲜牛奶样品中的乳糖含量为定量检测目标,进行散射光谱主成分得分累计贡献率的分层分段规定化映射预处理,利用偏最小二乘(PLS)回归分析建模手段,对相应近红外光谱中的糖含量信息进行测试及分析。结果表明,经过SR预处理后,牛奶中乳糖含量PLS模型的校正集样品交互验证预测偏差降低23.9%,实际预测偏差降低27.8%;验证集实际预测偏差降低16.7%。该SR光谱预处理方法兼顾光谱、参考值及组分相关性等多尺度信息,以实现光谱信息增强去噪,能避免有用信息误删,防止不充分拟合及过拟合。 相似文献
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钪(Sc)被广泛用于固体氧化燃料电池、陶瓷材料、催化剂与轻质高温合金等的制造,是不可或缺的重要战略资源,稀土矿石中Sc元素的定量分析对于稀土矿的勘探、开采具有重要意义。笔者提出了一种基于激光诱导击穿光谱(LIBS)结合随机森林(RF)算法的稀土矿石样品中Sc元素定量分析的方法。首先,考察了不同光谱预处理方法对RF校正模型预测性能的影响;然后,利用变量重要性测量(VIM)进行RF校正模型输入变量的选择与优化。为了进一步验证VIM-RF模型的预测性能,将其与标准曲线法、偏最小二乘(PLS)以及基于波段选择的RF模型进行了比较。最后,在最优化的光谱预处理(WT)和VIM阈值(阈值为0.016)等条件下,建立了基于小波变换结合VIM的RF校正模型。结果表明,VIM-RF校正模型表现出了良好的预测性能:R2CV为0.9981,RMSECV为0.0430 mg/kg,MRECV为0.0047,RP2为0.9993,RMSEP为0.4964 mg/... 相似文献
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快速检测活体水果内部品质对于确定水果最佳采摘时机和果园信息化管理具有重要意义。以南方棚栽葡萄为研究对象,应用光谱技术对处于生长期的四个葡萄品种的可溶性固体含量(SSC)进行现场测试。分别采用偏最小二乘法(PLS)回归、潜变量人工神经网络(LV-ANN)和潜变量支持向量机(LV-SVM)三种方法为光谱建模集建立了SSC校正模型。用验证集对模型的预测性能进行了评价。与PLS和LV-ANN模型相比,LV-SVM模型的预测性能最佳。实验结果表明,将光谱技术与LV-SVM建模法相结合适用于果园葡萄活体可溶性固体含量无损检测。 相似文献
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Meihua Shen Wilfred Pau Nicolas Gani Jianping Wen Shashank Deshmukh Thorsten Lill Jian Zhang Hanming Wu Guqing Xing 《半导体技术》2004,29(8)
This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration. 相似文献
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White organic light-emitting devices based on fac tris(2- phenylpyridine) iridium sensitized 5,6,11,12-tetraphenylnap -hthacene 总被引:1,自引:0,他引:1
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V. 相似文献
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Complete approach to automatic identification and subpixel center location for ellipse feature 总被引:1,自引:0,他引:1
XUE Ting WU Bin SUN Mei YE Sheng-hua 《光电子快报》2008,4(1):51-54
To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction. 相似文献
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Credence Systems Corporation 《半导体技术》2004,29(9)
Integrated circuits (ICs) intended for increasingly sophisticated automotive applications bring unique test demands. Advanced ICs for applications such as highly integrated automatic braking system (ABS) and airbag controllers combine high voltage digital channels, significant VI demands and precise timing capability. Along with continued missioncritical reliability concerns, the trend toward higher voltage operation and increased device integration requires specialized test capabilities able to extend across the wide operating ranges found in automotive applications. Among these capabilities, automotive test requirements increasingly dictate a need for a cost-effective versatile mixed-signal pin electronics with very high data rates reaching up to 50MHz with a voltage swing of-2 V to +28 V. 相似文献
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It is of interest to get appropriate information about the dynamic behaviour of rotating machinery parts in service. This paper presents an approach of optical vibration and deviation measurement of such parts. Essential of this method is an image derotator combined with a high speed camera or a laser doppler vibrometer (LDV). 相似文献
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Zhang Xinsheng 《中国通信》2014,(1)
正Happy New Year!As we step into a new year,we take a look back at the key feature topics covered in China Communications over the past 12 months and set out our expecta- 相似文献
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正For a long time,optical and wireless systems/net-works are developed in separate communities witha few attempts for in-depth convergence.In fact,it prom-ises many advantages to combine the optical and wire-less technologies in the levels of systems and networks.Recently,both academia and industry have made manyefforts to enter a new phase of development to take op-tical and wireless systems as fully integrated networks.To provide high bandwidth and reliable service for bothfixed and mobile users,a well-designed network must 相似文献
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