The Interpretation of Diffuse Reflectance Spectra.
The Interpretation of Diffuse Reflectance Spectra.
复制标题
DOI：
10.6028/jres.080a.056
复制
发表时间：
1976-07
期刊：
影响因子：
--
通讯作者：
Hecht HG
中科院分区：
文献类型：
--
作者：
Hecht HG
已经描述了散射介质的漫反射性质的许多处理。许多理论给出了一个适当的帐户的反射率为一组特定的条件下，模型的构建和实验测试的解决方案。这里只考虑那些被认为是相当普遍的模型。将理论分为基于连续统模型的理论和基于统计模型的理论是方便的。连续介质模型通常用两个唯象常数来描述给定介质的散射和吸收特性。这些模型都可以看作是辐射传输一般方程的不同层次的近似解。这为各种理论的比较提供了方便的基础。统计模型基于来自各个层或粒子的透射率和反射率的总和。因此，必须对基本单位的性质做出一些假设，而最终结果的有效性将取决于这些假设与现实的吻合程度。只有统计模型导致的表达式，绝对吸收率和散射系数可以计算和相关的实际颗粒特性。将讨论各种模型之间的关系，并根据每个代表吸收率和散射系数的功能将进行比较，并与现有的实验数据。这就需要考虑适当的模型系统和标准的特点。
Numerous treatments of the diffuse reflecting properties of scattering media have been described. Many theories give an adequate account of the reflectance for a specific set of conditions for which the model was constructed and the solution tested experimentally. Only those models which are considered to be fairly general are considered here. It is convenient to divide the theories into those based upon continuum models and those based upon statistical models. The continuum models typically describe the scattering and absorbing properties of a given medium in terms of two phenomenological constants. These models may all be regarded as varying levels of approximate solution to the general equation of radiative transfer. This provides a convenient basis for comparison of the various theories. The statistical models are based upon a summation of transmittances and reflectances from individual layers or particles. Thus, some assumptions must be made about the nature of the fundamental units, and the validity of the ultimate result will depend upon how closely these assumptions correspond with reality. Only the statistical models lead to expressions from which absolute absorptivities and scattering coefficients can be calculated and related to the actual particle characteristics. The relationship between the various models will be discussed and the features which typify the absorptivity and scattering coefficient according to each will be compared and related to the available experimental data. This leads to a consideration of the characteristics of appropriate model systems and standards.