利用近红外光谱技术预测杉木力学性质

利用三点弯曲实验方法测定了155个杉木样品的抗弯弹性模量和抗弯强度,并用近红外光谱仪采集其径切面和横切面的近红外漫反射光谱,以2/3的试样(103个)作为校正集建立抗弯弹性模量和抗弯强度的偏最小二乘法校正模型,以1/3的试样(52个)作为预测集对模型进行验证.结果表明,切面对模型预测效果的影响比较小,且与光谱区域的选择有关.对于可见近红外全波段光谱(350～2 500 nm)利用径切面比利用横切面光谱建立的力学性质模型的预测效果略好,对于短波光谱(780～1 050 nm)利用横切面比利用径切面光谱建立的模型的预测效果略好;降低波谱范围后,利用横切面短波近红外光谱建立的力学性质校正模型的效果与全波谱模型相比差异较小;利用径切面和横切面2个切面可见近红外全波段光谱、利用横切面短波光谱分别建立的杉木力学性质的校正模型,其预测相对分析误差在1.51～1.90之间,表明利用近红外光谱技术预测杉木木材的力学性质的能力属普通,可用之作为初步的检测工具.

Prediction Mechanical Properties of Chinese Fir Wood by Near Infrared Spectroscopy

Mechanical properties and the visible and near infrared(NIR)(350~2 500 nm)spectra obtained from radial longitudinal and transverse faces of 155 small clear wood samples of Chinese fir(Cunninghamia lanceolata) were measured, and 103 of them were used to establish calibration models.Calibrations were tested on an independent set(52 samples).Differences between calibrations developed by using the radial longitudinal and transverse faces were small.The calibrations developed by using NIR spectra collected from transverse faces were inferior to those developed by using NIR spectra collected from radial longitudinal faces.When reducing the spectral range to between 650 and 1 050 nm,the calibrations developed by using NIR spectra collected from radial longitudinal faces were inferior to those developed by using NIR spectra collected from transverse faces,and reducing the spectral range causes no decrease in the quality of the models developed using NIR spectra collected from transverse faces.Partial least square(PLS) modeling and test showed that calibrations developed using the visible and NIR spectra and calibrations developed by using the reducing spectral range(780~1 050 nm) from the transverse faces were moderate,and have a RPD range from 1.51 to 1.90.It was concluded that NIR spectroscopy can be used as an initial screening.