Abstract:Biosurfactant” refers to a group of natural products (from biological metabolites or plant extracts) with surface activity. In terms of cleaning smudges on paper, biosurfactants boast stronger cleaning effects compared with warm water, and are not as destructive to paper as chemical reagents due to their weaker acidity or alkalinity and their natural degradation of residues. We first investigated the optimum conditions for cleaning iron-containing ink smudges using several biosurfactants. The results show that the best cleaning effect of sophorolipid appeared under the conditions of 50 ℃, a concentration of 2.5% and 40 min, which gave a maximum cleaning degree of 66%. Then the cleaning effects of sophorolipid and of KMnO₄-H₂C₂O₄ (a commonly-used chemical cleaning agent) were compared. The results show that sophorolipid had no destructive effect on either the paper fibers or the carbon-containing ink writing, although its degree of cleaning was lower than that of the chemical reagent. Finally, through analyses by X-ray fluorescence (XRF) and oxidation-reduction potential (ORP), we infer that the cleaning mechanism of sophorolipid involves either complexation reactions with iron tannate and iron gallate or a surface interaction with additives such as gum Arabic in iron-containing ink smudges.

Abstract:Acidification is the main cause of self-destruction of paper files, cultural relics and books, etc. Since the existing deacidification methods are not that practical, innovation and breakthroughs are required. The traditional aqueous solution method not only does well in deacidification, but is safe to paper, environmentally friendly, easy to do and economical as well. Therefore, if its shortcomings could be overcome, this deacidification method may have broader prospects of application. In light of this, in our study we supplemented the traditional aqueous solution method of paper deacidification with electrolysis. The working principle is that acidified paper in a wet state and an external DC power source forms an electrolytic cell which quickly removes charged particles (e.[KG-0.8mm]g.[KG-1mm], protons) from the paper, achieving quick deacidification. After using the traditional aqueous solution method and the innovative electrolysis method to treat naturally acidified paper, we analyzed the appearances and properties of the paper before and after deacidification. The results show that the electrolysis method can effectively remove protons from the paper and reduce its acidity. The innovation not only is simple and reliable, green, safe and of lower cost than the traditional method, but also overcomes the problems including deformation, expansion and low work efficiency associated with the long-term wet state of paper.

Abstract:Unidirectional migration and evaporation of water are important causes of various diseases of indoor earthen sites. In the past, it was difficult to prevent such diseases using various chemical materials. Using the technique of artificial “water replenishment by gas-liquid phase transition” and the principle of not changing the original soil, the water balance of indoor earthen sites was maintained and controlled, resulting in a stable soil salinity and the prevention of soil cracking and pulverization. This method may become a new technology for earthen site protection. For this reason, we took the earthen site of Kuahuqiao Site Museum as an example, and carried out a series of experiments, including conducting lab-scale experiments of gas-liquid phase transitions, developing water vapor condensation rate equations and carrying out an on-site water replenishment experiment at the indoor earthen site. The impacts of various conditions on the rate of water replenishment have been explored in a preliminary way, and the feasibility and effect of water replenishment by gas-liquid phase transition have been verified. Hopefully our research will provide the basis for larger-scale experiments in the future.

Abstract:Takamatsuzuka Tumulus is a national cultural heritage site in Japan, and the in-situ conservation of this site was considered to be an international paragon for the field of cultural heritage conservation in the last century. Nevertheless, the gradually uncontrolled biodeterioration resulted in the dismantlement of the ancient tumulus to be conserved ex-situ. It now deserves further rethinking and exploration as to whether those complex artificial intervention methods were conductive to the in-situ conservation of tomb murals. This paper reviews the conservation course of Takamatsuzuka Tumulus since its excavation, and mainly summarizes the existing studies of biodeterioration of the tumulus and the corresponding protection measures. In addition, this paper also makes a comprehensive review and interpretation of related literature about the archaeological site and its contents, including the characteristics of microbial communities involved in the biodeterioration, changes of environmental factors as well as control and intervening measures. It objectively evaluates the research progress, experience and lessons of the Takamatsuzuka Tumulus conservation, and provides a reference for the future conservation of tomb murals preserved in the similar environments in China and other countries.

Abstract:A Jin Dynasty portrait brick tomb found at an archaeological site in Ganquan County was moved, intact, in order to support capital construction. In addition to information on traditional methods, infrared (IR) and ultraviolet (UV) photography, portable X-ray fluorescence (XRF) spectrometry and colorimetry were utilized to reveal more information. The results show that the main colors of the portrait bricks are red, white and black, and that the yellow pigment has obvious fluorescence. We tentatively determined that hematite and red lead were used as pigments. The main diseases include flaking, cracking, detachment, and deep losses. In the whole process, the small environment and unstable diseases of the tomb were controlled at once. Foam board, composite board and wooden keel were used to support and reinforce the entire interior of the tomb, while gypsum and linen, as well as different types of steel were used to reinforce the exterior of the tomb. At the bottom, channel steel and H steel were inserted and welded to the tomb as a whole so that it could be hoisted and transported. In spite of various difficulties, the intact moving was a success and the tomb has become the largest one using this moving method so far. This effort provides a model for similar projects.

Abstract:A coffin board unearthed from Bijiatan in Huahai Town of Jiuquan, Gansu Province has a paper transcript of Jin Lyu Zhu (notes of laws in the Jin Dynasty) pasted on its outer side. Due to the complex burial environment and the long burial time, the state of preservation of both the coffin board and the paper were extremely poor. The board suffered from fracturing and cracking, while the degradation of the paper was even more serious. In order to realize the integrity of this cultural relic and to achieve the basic requirements needed for exhibition, we undertook conservation and restoration measures on the basis of existing research and related identifications and analyses. After treatment, the integrity of the coffin board has been presented and its strength enhanced, allowing it to meet the basic requirements for exhibition. The raw material analyses show that the paper is made from skin pulp fiber, so this report represents, so far, one of the few unearthed paper objects of the Wei and Jin Dynasties using this kind of raw material. The results provide valuable data for the study of raw papermaking materials in Hexi area of Gansu Province.

Abstract:Ancient silks unearthed from wet areas are rare and precious and therefore, due to degradation of the dyestuffs, it is difficult to know their original colors. In this study, ancient Han silk fabrics unearthed from Tomb No.2 at Yinwan in Lianyungang were analyzed by ultra-high performance liquid chromatography-mass spectrometry (HPLC-MS) in order to identify the dyestuffs. According to the results and relevant documentary records, we found that Caesalpiniaceae was used for coloring the textile. The identification of Caesalpiniaceae as the dyestuff not only adds to the information about dyeing technology used in the Western Han Dynasty, but also provides scientific reference for the conservation and restoration of ancient textiles excavated from wet areas.

Abstract:Overglaze porcelain inlay panels used for the interior decoration of Yan Qu Lou and Cui Shang Lou in Ning Shou Gong Garden of the Forbidden City are precious specimens for investigating the craftsmanship of overglaze porcelain from the Qianlong period. In our study, an energy dispersive X-ray fluorescence (EDXRF) spectrometer, a micro-laser Raman spectrometer and an optical microscope were used to non-destructively analyze overglaze porcelain samples from the Qianlong period. The results show that the base glaze for blue and rouge red colors is lead-potassium glass, while that of white, yellow, yellow green and green colors is lead glass. For the white color, the opacifier and colorant are both lead arsenate; for the blue color, the colorant element is cobalt (Co) and the opacifier is lead arsenate; for the yellow color, the opacifier and colorant are lead tin yellow (type II); formation of the yellow green color was the coactions of lead tin yellow (type II) and copper (Cu); for the rouge red and green colors, the colorant elements are gold (Au) and copper (Cu), respectively; the black color was fully presented by covering the transparent green color over asbolite (Zhumingliao); the orange color was colored and opacified by hematite; and the brown color was formed by the coactions of hematite and elements manganese (Mn) and cobalt (Co).

Abstract:Jade artifacts excavated from Moyishan Site in Zengcheng District were important archaeological findings in Guangzhou in 2016. In order to investigate the mechanism of weathering and to evaluate the state of preservation of the Moyishan jade, we analyzed the materials and structure of the Moyishan jade, using Raman spectrometry, X-ray diffraction (XRD), X-ray fluorescence (XRF) spectrometry, scanning electron microscopy and energy dispersive X-ray fluorescence spectrometry (SEM-EDX). The results confirm for the first time that the main material of the jade is tremolite. Moreover, we also analyzed the phase, composition and structure as well as pH value of the soil around the jade. Combining the analytical results of the jade and the soil and the climatic conditions of the site, we finally explored the alteration characteristics of the Moyishan jade in a strongly acidic environment. The study could help to enrich the understanding of the mechanism of weathering of jade, which will be conducive to formulating protective measures for loosing jade in a scientific way.

Abstract:In our study, we analyzed the elemental content and distribution on the surface and at different sampling depths longitudinally and transversely, the phases of the sediments on the surface and the particles on the longitudinal and transverse sections of waterlogged archaeological wood, using inductively coupled plasma (ICP) spectrometry, X-ray diffraction (XRD) and micro-confocal laser Raman spectrometry. The results show that waterlogged archaeological wood is rich in the elements, iron (Fe), sulfur (S) and calcium (Ca), and that the sediments containing these three elements are mainly composed of insoluble salts and other insoluble substances. The insoluble salts are mainly divided into two categories, namely, calcium salts (including sulfate, carbonate and phosphate), and iron sulfides (including troilite, pyrite and pyrrhotite). The other insoluble substances include various types of iron oxides (such as goethite, hematite and lepidocrocite, hydrated ferric oxide) and elemental sulfur, etc. The analytical results for these insoluble salts contribute to an understanding of the preventive control and effective removal of insoluble salts on or in waterlogged archaeological wood, especially those seriously harmful to the waterlogged archaeological wood.

Abstract:Guyue Bridge, built in the Southern Song Dynasty (1213 A.D.), is located in Yiwu, Zhejiang Province. It is a rare example of the transition of folding-arch bridges and possesses high historical, scientific, artistic, cultural and social values. Facing the deteriorated bridge and severe environmental problems, our conservation team conducted a survey using a variety of methods, including 3D laser scanning, micro-testing and structure simulation, etc., to research diseases of the bridge and also analyzed their mechanisms and relationships. Comprehensive and precise judgments about the stability and state of preservation of the bridge were made accordingly. The application of multiple methods provides not only mutual verification of the survey results, but significant evidence for future restoration and conservation as well.

Abstract:In our study, we used the multi-channel transient Rayleigh wave method and geological prospecting data, to detect the karst fractures in the rock masses bearing cliffside inscriptions in the Seven Star Cave of Guilin. The results reveal the scale and distribution of karst fractures that cause the cliffside inscriptions to be eroded due to water in the karst fractures. Application of the multi-channel transient Rayleigh wave method to karst fracture exploration provides not only a scientific basis for protection of cultural relics involving wall carving, but also experience and references for other relevant engineering projects.

Abstract:At damp earthen sites, groundwater and rainwater infiltration are the main causes of damage, which can easily lead to the softening and collapse of soil, as well as the growth of mildew and weeds, etc. The same problems were encountered in connection with the protection of an Eastern Zhou sacrificial horse pit site in Linzi District of Zibo, Shandong province. Initially, in order to control the dampness and resulting decay of horse bones caused by water, chemical waterproofing and chemical reinforcement measures were used; however, the problems were not solved. Subsequently, a method of setting an arch in the lower excavation was adopted, and it successfully controlled the influence of groundwater and rainwater. After 30 years of practice, this method has proved reliable. This paper introduces and summarizes the application of the arch bond method for the protection of sacrificial horse pits, and hopefully could provide a reference for similar work in the future.

Abstract:An acrobat figurine has been excavated from Pit K9901 of Emperor Qinshihuang’s Mausoleum. In our study, we analyzed the yellow, black and white pigments on it, using polarized light microscopy (PLM), scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and Raman spectrometry. The result indicates that they are all mineral pigments. The yellow pigment is from the mimetite group, the black pigment is copper oxide (CuO) with red ferric oxide (Fe₂O₃) particle inclusions, and the white pigment is hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂]. There are not only differences but also connections between these pigments and those of the terra-cotta warriors. The study of these pigments provides us with important information in terms of exploring splendid archaeological culture of Emperor Qinshihuang’s Mausoleum.

Abstract:The Cemetery of Guo State in Sanmenxia is an important archaeological site to study the culture of princes in the late Western Zhou Dynasty. In Tomb M2009, a pair of hemp shorts and a piece of hemp short gown were found. This collection of hemp fabrics is one of the few Western Zhou costumes preserved to date. The hemp fabrics are divided into two layers. The inner layer was apparently dyed with a bright red color artificially. In our study, we analyzed and identified the red particles on the hemp shorts, using energy dispersive spectrometry (EDS) and micro-confocal laser Raman spectrometry. According to the results, the main component of the red particles is ferric oxide (Fe₂O₃), which is also the main component of natural ocher, indicating that the red color on the hemp fabric was the result of dyeing with ocher. This discovery provides empirical evidence of the use of ocher for clothing dyeing in the Western Zhou Dynasty.

Abstract:Temperature and relative humidity are basic indicators for the monitoring of museum environments. In order to better understand a great many temperature and humidity monitoring data, the K-line diagram was introduced to the temperature and humidity evaluation system. According to the four elements of K-line diagram, the initial value, the end value, the maximum value and the minimum value during the sampling period are defined and correspond respectively to the initial price, the closing price, the highest price and the lowest price of K-line diagram (in the business world, where K-line originated). Using the continuous monitoring data from a temporary exhibition, we evaluated the temperature and humidity in the exhibition hall and some showcases using K-line diagrams. The comparison between the regulation effects of active humidity control and passive humidity control provides a reference for the selection of humidity control methods for short-term exhibitions. This paper establishes an environmental monitoring data analysis model for the data processing of temperature and humidity in museum environments and provides an intuitive discussion plan for the environmental quality assessment of cultural relic conservation.

Abstract:During the rapid progress of rare books preservation in China, many new problems and challenges have emerged. Although they cannot be adapted perfectly for China, the Italian approaches in art conservation and education are nonetheless quite valuable. Division and collaboration of conservation works, conservation courses with balanced social sciences, natural sciences and practice, dissemination of the concept of art preservation, reasonable credit hours, gradually progressing lessons, professional faculties, passionate citizens for art preservation and their respect towards conservators, to mention just a few, are all worth studying in order to benefit from te Europeans’ wisdom, which may eventually nourish the career of rare books preservation and the education for art conservation in China.