共查询到20条相似文献,搜索用时 156 毫秒
1.
2.
3.
应用Bruker Matrix I近红外光谱仪,扫描了176个烟叶样品,扫描波数4000~9000cm~(-1),分辨率8cm~(-1),扫描次数64,数据经一阶偏导9点平滑处理后,以Unscrambler软件建立近红外光谱对评吸得分的模型,以150个样品为校正集合,26个样品为预测集,偏最小二乘法建立的回归模型相关系数(correlation)0.99372,校正标准差(SEC)0.21135,斜率(slope)0.987603,模型拟合较好。利用建立的模型预测26个样品的评吸收得分,结果表明,最大预测绝对偏差1.86,最小绝对偏差0.01,平均绝对预测偏差1.09分,所建模型有实际意义。 相似文献
4.
基于径向基函数网络的茶多酚总儿茶素近红外光谱检测模型的研究 总被引:20,自引:10,他引:10
基于径向基函数神经网络(RBFN)建立了茶多酚总儿茶素含量的近红外光谱分析模型。茶多酚光谱采用小波压缩、标准化处理后,进行主成分分解,以主成分光谱作为RBFN的隐层输入函数,并通过改变主成分数对模型进行优化。当主成分数为7时得到了RBFN优化模型,该模型对定标样品集、全样品集和预测样品集的预测值与实际值回归系数R分别为0.999,0.999和0.992,预测均方误RMSEP分别为1.08%,2.06%和3.68%。 相似文献
5.
近红外光谱法快速测定葛根中的五种成分 总被引:9,自引:4,他引:5
本文应用近红外光谱技术建立了快速检测葛根中有效成分的方法。研究了优化分析葛根总异黄酮、葛根素、大豆苷、淀粉和粗蛋白含量数学模型的各种条件,结果表明:建模样品集的化学值(又称真值)与近红外预测值的相关系数分别为:葛根总异黄酮R= 0.9752,葛根素R=0.9839,大豆苷R=0.9659,淀粉R=0.9628,粗蛋白R=0.9829;检验样品集的化学值与近红外预测值的相关系数分别为:0.9818,0.9752,0.9772,O.9737和0.9798。说明所建模型具有实际应用价值。 相似文献
6.
7.
8.
近红外光谱分析技术在煤品质快速分析中的应用 总被引:1,自引:0,他引:1
煤品质快速分析对于企业在煤收购、使用、加工等环节都具有重要的指导意义,本文提出利用近红外光谱分析技术对煤品质进行快速分析的方法;通过实验采集了110份煤粉样品的近红外漫反射谱图,选取了其中80份样品作为建模校正集,另外30份样品作为预测验证集;分别建立挥发分、弹筒热值、高位热值、低位发热量的定标模型,其中交互验证预测相关系数(RCV)均优于0.85;外部验证预测相关系数(RP)均优于0.95。研究结果表明:利用近红外光谱分析技术对煤品质进行快速分析具有可行性。 相似文献
9.
10.
近红外拉曼光谱在检测白酒酒精含量的应用 总被引:1,自引:0,他引:1
本文初步探讨了运用近红外拉曼光谱技术检测白酒酒精度的可行性。给出了将全光谱数据利用BP人工神经网络所建模型和小波处理后的光谱数据利用偏最小二乘回归所建模型,并与拉曼传统方法-特征峰强比值法的预测结果进行了比较。结果表明,利用小波消噪后的数据建立的模型效果最好,预测相关系数R由传统方法的0.914 3提高到0.968 7,均方根误差由2.064 6降为1.585 9,说明对于含水较多且成分复杂的样品,拉曼光谱分析技术是可行的,并且比传统的建模方法效果好,利用小波预处理后全光谱建模效果更好。 相似文献
11.
In this paper, a signal processing method is proposed to derive the impulse responses of the defect impacts for a roller bearing, and is carried out in two steps. First, the envelope detection for the vibration signal with amplitude modulation is implemented through the linear least square analysis under the assumption of a stepwise function for the envelope signal. Secondly, the signal processing of impulse-response enhancement is applied to eliminate the sidebands around the defect frequencies. The impulse responses of the defect impacts could be derived and the sidebands in the impulse-response spectrum could be theoretically eliminated. Accordingly, the spectrum would be helpful to apply in the bearing defect diagnosis, especially under the condition of non-uniform loading. From the theoretical analysis and the experimental studies, it is shown that the proposed signal processing method could effectively derive the impact responses of the defects impacts for a roller bearing system and the sidebands in the impulse-response spectrum could be reduced or even eliminated. 相似文献
12.
13.
S. M. Ishikaev 《Instruments and Experimental Techniques》2002,45(3):426-430
A system of four coaxial pickup coils connected in series and designed on the basis of a modified scheme of a symmetrical second-order gradiometer is described. The conditions under which a measurement zone insensitive to displacements of a sample forms in this system of coils are determined. This makes it possible to almost eliminate the error caused by the inaccuracy of setting the sample at the geometrical center of the pickup coils. It is shown that this system keeps a high sensitivity to the sample's magnetic moment and is insensitive to the signals produced by the sample holder and thermocouple due to the compensation of signals in all the coils. The main characteristics of the system of coils described and the commonly used first-order gradiometer are compared. 相似文献
14.
15.
16.
光谱技术在植物油脂掺伪和地沟油检测上的应用 总被引:1,自引:0,他引:1
综述了红外光谱、近红外光谱、紫外吸收光谱等光谱技术在植物油脂掺伪以及地沟油检测中的应用。介绍了红外光谱技术、近红外光谱技术等检测油脂的原理和检测方法的优缺点。展望了光谱技术特别是红外光谱技术和近红外光谱在地沟油检测中的应用前景。提出多种方法联合运用的检测掺伪油脂和地沟油的新思路。 相似文献
17.
For clear interpretation of a sample's surface properties, several simple and general relations between phase shifts of atomic force microscopy (AFM) and sample's properties are derived. The topography and dissipation measurement errors due to some inherent uncertainties are investigated. For derivation of these simple and general relations among measuring signals and sample's properties, the dynamic behavior of a cantilever is simulated into a mass-spring-damper model. In general, the conventional model can determine the first mode only. The dynamic effective spring theory is introduced here. Based on this theory, the conventional model can be modified to accurately determine the dynamic motions of higher modes of a cantilever. If the dynamic behavior is almost harmonic, the exact dynamic response of the general system subjected to arbitrary tip–sample force is derived. Moreover, several simple and general relations among dynamic responses of AFM and sample's properties are discovered. Based on these relations, the errors of measuring a sample's surface properties due to the inherent measuring uncertainties are investigated. Finally, some methods to minimize the error of measurement are proposed. 相似文献
18.
某轿车前副车架服役载荷模拟试验加速方法研究* 总被引:7,自引:1,他引:6
服役载荷模拟试验能准确地预测零部件的疲劳寿命。为节省试验时间,急需开发出一套合理、实用的加速试验方法。重点研究在不具备结构局部应变响应,仅具备外部激励载荷如力、位移、和加速度等情况下的试验加速方法。基于修正Miner准则,以伪损伤保留比例作为小载荷删除准则,并结合疲劳数据编辑(Fatigue data editing, FDE)技术,提出一套便于工程应用的服役载荷模拟试验加速方法。以某轿车前副车架的疲劳试验为例,分别编制伪损伤保留比例为99%、95%和90%的加速谱。综合考虑各加速谱的载荷特征和加速效果,选用95%加速谱、90%加速谱和原始谱分别建立台架试验。试验结果表明两种加速谱在有效节省试验时间的同时,均获得了与原始谱相同的试验结果,且90%加速谱的加速试验效果更为显著。本方法便于工程应用,可为其他汽车零部件的服役载荷模拟试验提供参考。 相似文献
19.
PCS纳米颗粒粒度测试装置的研究 总被引:1,自引:0,他引:1
介绍了光子相关谱技术(PCS)测量纳米颗粒粒度的基本原理和PCS纳米测量装置的基本组成。因为纳米颗粒散射光所呈现的光谱是由颗粒粒径决定的,所以在纳米颗粒粒度测量中,单一角度测量只能观测到样品的部分情况。为了充分保证检测样品的真实表征及提高信噪比,文中提出了一个将步进电机和光纤联合应用于纳米颗粒粒度测量的设计方案。采用这个方案可以准确和方便地在不同角度上进行纳米颗粒粒度测量,而且有效地提高了信噪比和减小了装置的体积。 相似文献
20.
本研究采用计算化学方法、应用Gaussian03化学软件,研究3-乙基戊烷的中心C原子被N原子取代后成为三乙胺后,三乙胺和3-乙基戊烷红外光谱的区别,并且研究这两种具有等电子类似结构分子的稳定性。通过比较它们的红外谱图得知,C原子被N原子代替以后,三乙胺的C-H红外峰大部分发生蓝移,少数C-H红外峰发生红移;同时,三乙胺红外谱图与3-乙基戊烷红外谱图比较,增加了四个C-N(包括C-N-C)拉伸和剪切红外峰,分别对应在1238.47、1175.40、1085.81和1026.70 cm-1位置上。经分析,3-乙基戊烷的稳定性好于三乙胺。 相似文献