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首页> 外文期刊>Journal of near infrared spectroscopy >A review of band assignments in near infrared spectra of wood and wood components
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A review of band assignments in near infrared spectra of wood and wood components

机译：木材和木材组分近红外光谱中的谱带分配研究

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Near infrared (NIR) spectra of wood and wood products contain information regarding their chemical composition and molecular structure. Both influence physical properties and performance, however, at present, this information is under-utilised in research and industry. Presently NIR spectroscopy is mainly used following the explorative approach, by which the contents of chemical components and physico-chemical as well as mechanical properties of the samples of interest are determined by applying multivariate statistical methods on the spectral data. Concrete hypotheses or prior knowledge on the chemistry and structure of the sample - exceeding that of reference data - are not necessary to build such multivariate models. However, to understand the underlying chemistry, knowledge on the chemical/functional groups that absorb at distinct wavelengths is indispensable and the assignment of NIR bands is necessary. Band assignment is an interesting and important part of spectroscopy that allows conclusions to be drawn on the chemistry and physico-chemical properties of samples. To summarise current knowledge on this topic, 70 years of NIR band assignment literature for wood and wood components were reviewed. In addition, preliminary results of ongoing investigations that also led to new assignments were included for discussion. Furthermore, some basic considerations on the interactions of NIR radiation with the inhomogeneous, anisotropic and porous structure of wood, and what impact this structure has on information contained in the spectra, are presented. In addition, the influence of common data (pre)-processing methods on the position of NIR bands is discussed. For more conclusive band assignments, it is recommended that wood is separated into its components. However, this approach may lead to misinterpretations when evaluation methods other than direct comparison of spectra are used, because isolation and purification of wood components is difficult and may lead to chemical and structural alterations when compared to the native state. Furthermore, "pure" components have more distinct and symmetric bands that influence the shape of the spectra. This extended review provides the reader with a comprehensive summary of NIR bands, as well as some practical considerations important for the application of NIR to wood.
机译：木材和木制品的近红外（NIR）光谱包含有关其化学成分和分子结构的信息。两者都会影响物理性能和性能，但是，目前，该信息在研究和工业中并未得到充分利用。目前，近红外光谱法主要是按照探索性方法使用的，通过对光谱数据应用多元统计方法来确定目标样品的化学成分和理化含量以及机械性能。建立这样的多元模型并不需要关于样品的化学和结构的具体假设或先验知识（超过参考数据）。但是，要了解基础化学，必不可少的知识是在不同波长处吸收的化学/官能团，并且必须分配NIR波段。谱带分配是光谱学中一个有趣而重要的部分，它可以得出关于样品化学和物理化学性质的结论。为了总结有关该主题的当前知识，对70年的NIR波段指配文献进行了回顾。此外，讨论中还包括正在进行的调查的初步结果，这些结果也导致了新的任务。此外，提出了一些有关NIR辐射与木材的非均质，各向异性和多孔结构相互作用的基本考虑，以及该结构对光谱信息的影响。此外，讨论了常用数据（预处理）方法对NIR波段位置的影响。对于更确定的频段分配，建议将木材分成其各个组成部分。但是，当使用除光谱的直接比较以外的评估方法时，此方法可能导致误解，因为与天然状态相比，分离和纯化木材成分很困难，并且可能导致化学和结构改变。此外，“纯”组分具有影响光谱形状的更明显和对称的谱带。这份扩展的评论为读者提供了近红外波段的全面概述，以及一些对于将近红外应用于木材的重要实践考虑。

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