Min Luo,Peng Bo,Yang Shao,Zhiming Liu,Diandou Xu,Lingling Ma
Murals are one of the important cultural heritages of mankind. The microbial control of murals is an important subject in mural painting conservation. In recent years, electron beam radiation sterilization has attracted more and more attention in the field of cultural relic protection. Murals are immovable cultural relics, so conventional electron beam irradiation equipment can not be used. However, the development of small mobile electron beam irradiation equipment shows the potential of radiation’s application in the sterilization protection of immovable cultural relics such as murals. A feasibility study of radiation sterilization in mural paintings is needed to investigate the effect of sterilization and the influence of sterilization dose on the stability of mural painting pigments and bonding materials. In this paper, the radiation effects of typical bacteria in tomb murals and mineral pigment powder in ancient Chinese paintings were studied in a laboratory. Firstly,aeromonas hydrophila(Aer.h) andpenicillium flavigenum(PNC) were selected as representative strains to determine the appropriate sterilization dose for murals. Then, the effects of radiation on seven kinds of ancient Chinese mineral pigments and white calcium carbonate in the ground layer were verified. The results are as follows: the radiation dose of 10 kGy can effectively remove the two typical strains. This sterilization dose will cause a color difference in calcium carbonate and lead white, while other color pigments are essentially stable. Based on the color difference and UV-vis intensities of the four white carbonate samples, the color change in two of them increased with increasing the dose up to 30 kGy, after which signs of saturation began to appear. X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge structure (XANES) spectra showed that the chemical structure of the samples did not change after irradiation. The formation of free radicals in treated samples was confirmed using an electron paramagnetic resonance (EPR) spectrum test. According to all characterization results, the color difference between the four white carbonate samples may be due to the combination of unpaired electrons and defects in the process of electron beam irradiation to form color centers. After forming the color center, the light absorption of the four samples changed. This is a reversible change, but the samples will take a long time to return to their original state. This study focuses on the influence of electron beam radiation on pigment composition, which is a preliminary exploration of whether radiation sterilization can be applied to the protection of ancient Chinese mural paintings, and the experimental results can provide basic data for later application.Keywords:electron beam radiation;mural protection;radiation sterilization;mineral pigment;chromatic aberration
Yang Yuping,Zhai Dongwei,Zhang Zhenwei,Zhang Cunlin
Nondestructive analysis of historical objects is of significance for cultural heritage conservation. In this paper, terahertz time-domain spectroscopy (THz-TDS) was used to distinguish seven red mineral pigments used in ancient Chinese artworks. Two absorption features of natural minerals HgS and four highly resolved spectral features of mineral pigment Pb 3 O 4 were observed and identified as their fingerprints in the range 0.2 to 3.0 THz, based on which the spatial distribution of individual chemical substances including cinnabar, vermilion, and red lead were clearly revealed at various frequencies using terahertz spectroscopy imaging. Moreover, a noncontact evaluation of thickness changing and dehydration of a wet painting was monitored by inferring time delay as well as signal amplitude of THz pulses transmitted through the painting. In order to demonstrate the feasibility of THz-TDS and THz imaging for authentic artworks detection, a complete set of THz analysis of two nineteenth century wall paintings discovered in the Fuchen Temple of the Forbidden City, Beijing, was performed and the results indicate that THz measurement techniques provide a noninvasive and nondestructive solution for the care, preservation, and restoration of cultural relics.
Na Wang,Jing Liu,Ling He,Tie Zhou,Bo Rong,Liang Wang,Xiang Zhao
An effective method for characterizing Chinese lacquer as binding medium in historical artwork has been developed by on-line methylation pyrolysis-gas chromatography–mass spectrometry (pyrolysis GC–MS). The characteristic pyrolytic components of Chinese lacquer were identified in artificially aged pure and pigmented lacquer. Methylation of urushiol (mainly composed of catechol derivatives) was performed by adding tetramethyl ammonium hydroxide to convert phenolic hydroxyl groups into methylated derivatives to improve the resolution of catechol derivatives and urushiol monomers. The mechanism of formation of small molecular components was proposed, and the influence of different mineral pigments (azurite, malachite, ochre, and cinnabar) on the determination of characteristic components was discussed. Aliphatic hydrocarbon components, benzene derivatives, catechol derivatives, and urushiol monomers were proposed as characteristic pyrolytic components. In addition to 3-pentadecene-catechol, 3-pentadecane-catechol, and 3-heptadecene-catechol, 3-pentadecene-phenol was also identified as an urushiol monomer in Chinese lacquer. Four pigments slightly reduced the detection of aliphatic hydrocarbon components, but were unconspicuous for the detection of benzene derivatives. Azurite, malachite, and cinnabar decreased the measurement of urushiol monomers, but ochre significantly increased their relative abundance. The established on-line methylation pyrolysis GC–MS procedure and summarized data were successfully applied to the identification of samples collected from Terra-Cotta Warriors and Horses of Qin Dynasty (221–207 BC), Han Yang Mausoleum of Han Dynasty (206 BC–24 AD), and Dazu Grotto of Tang Dynasty (618–907 AD).
危险品化学品经营许可证（带存储）