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This article presents an integrated analytical method to investigate the polychrome clay sculptures of the Qinglian Temple in Jincheng City, Shanxi Province, China. Digital microscopy, SEM-EDS, XRD, Herzberg stain, Micro-Raman spectroscopy and FT-IR were selected to identify the raw materials and techniques used to produce the ground clay layer, the white powder layer and the mineral pigment of the polychrome clay sculptures. The investigation shows that the clay used to make the coarse and fine clay layer is consistent. However, different kinds of fibres were found mixed in the coarse and fine clay layers: wheat straw was the main fibre used in coarse clay layer, while the bast fibres, including ramie, kenaf and sisal hemp, were used as the fibre supports in the fine clay layers due to their useful properties. The white powder layer was made of a mixture of kaolinite and gypsum. For the mineral pigments, it principally contained red (hematite, minium or a mixture of minium and cinnabar), green (atacamite and atacamite), blue (azurite), yellow (yellow ochre), black (amorphous carbon) and white (the mixture of kaolinite and gypsum). Additionally, a gilding technique and multiple paint layers also typified many pigment areas. This work has furthered understanding of the materials and techniques used in making the sculptures of the Qinglian Temple and has clear implications for the restoration and conservation treatments on these kinds of ancient painted clay sculptures. [ABSTRACT FROM AUTHOR]

• Qualitative and quantitative methods were combined to characterize the Shanxi low-rank coal. • The proportion of aromatic carbon was 75.31% and the X BP was 0.15. • The average number of substituents on each aromatic ring was 4.56. • The carbon skeleton and molecular structure models were deduced and established. • The molecular formula of the Shanxi low-rank coal model was C 205 H 138 O 27 N 2 S. Due to the particular paleogeological structure of Shanxi, the macromolecular structure of Shanxi low-rank coal appears special characterizations. The combination of qualitative and quantitative methods showed that Shanxi low-rank coal was composed of amorphous carbon and ordered aromatic clusters, which was an intermediate turbostratic structure between amorphous and graphite. The molecular structure model and carbon skeleton structure model of the low-rank coal were drawn on this basis. The molecular model could simplify the molecular formula to be C 205 H 138 O 27 N 2 S, which was dominated by aromatic and aliphatic structures. The proportion of aromatic carbon in coal was 75.31%, mainly composed of 1∼2 benzene rings, and the aliphatic structure was composed of cycloalkyl and alkyl side chains. The carbon skeleton structure showed that the diameter of the aromatic layer of the coal was 1.89 nm, the interlayer spacing between crystal layers was 0.36 nm, the average number of aromatic flakes per stack was 3.78, and the value of stacking height was 1.00 nm. Supplementally, parameters such as crosslinking density (0.39) and A D /A G area ratio (0.79) also provided a deeper understanding of coal structure and laid the foundation for low-rank coal utilization. [Display omitted] [ABSTRACT FROM AUTHOR]