Pagnotta Stefano, Lezzerini Marco, Ripoll-Seguer Laura, Hidalgo Montserrat, Grifoni Emanuela, Legnaioli Stefano, Lorenzetti Giulia, Poggialini Francesco, Palleschi Vincenzo
1 Applied and Laser Spectroscopy Laboratory, Institute of Chemistry of Organometallic Compounds, Research Area of National Research Council, Pisa, Italy.
2 Department of Earth Sciences, University of Pisa, Pisa, Italy.
Appl Spectrosc. 2017 Apr;71(4):721-727. doi: 10.1177/0003702817695289. Epub 2017 Mar 21.
The laser-induced breakdown spectroscopy (LIBS) technique was used for analyzing the composition of an ancient Roman mortar (5th century A.D.), exploiting an experimental setup which allows the determination of the compositions of binder and aggregate in few minutes, without the need for sample treatment. Four thousand LIBS spectra were acquired from an area of 10 mm, with a 50 µm lateral resolution. The elements of interest in the mortar sample (H, C, O, Na, Mg, Al, Si, K, Ca, Ti, Mn, Fe) were detected and mapped. The collected data graphically shown as compositional images were interpreted using different statistical approaches for the determination of the chemical composition of the binder and aggregate fraction. The methods of false color imaging, blind separation, and self-organizing maps were applied and their results are discussed in this paper. In particular, the method based on the use of self-organizing maps gives well interpretable results in very short times, without any reduction in the dimensionality of the system.
激光诱导击穿光谱（LIBS）技术被用于分析古罗马灰浆（公元5世纪）的成分，利用一种实验装置，该装置能够在几分钟内测定粘结剂和集料的成分，而无需进行样品处理。从10毫米的区域采集了4000条LIBS光谱，横向分辨率为50微米。检测并绘制了灰浆样品中感兴趣的元素（H、C、O、Na、Mg、Al、Si、K、Ca、Ti、Mn、Fe）。将收集到的数据以成分图像的形式图形化显示，并使用不同的统计方法进行解释，以确定粘结剂和集料部分的化学成分。应用了假彩色成像、盲分离和自组织映射方法，并在本文中讨论了它们的结果。特别是，基于自组织映射的方法能在极短的时间内给出易于解释的结果，且不会降低系统的维度。
