Abstract:In this research, we attempted to identify the specific sources of the organic binding media from the Terra-cotta Army of Emperor Qinshihuang. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the organic matter extracted from the pigment layer and the result shows that the main components were fatty acids and their oxidation products. Further identification using gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) obtained the Δ¹³C values of stearic acid and palmitic acid, which were similar to those of ruminants. Combined with the literature, it was speculated that the bovine glue was used as the binding media for the pigments of the Terracotta Army. After the introduction of supercritical fluid extraction (SFE) and total lipid extraction (TLE), the extraction effects of the same sample were compared between different extraction methods. The result shows that the extraction efficiency was significantly improved to capture additional components via SFE, compared with the conventional chemical-reagent extraction method. Featuring the advantages of streamlined process, short time consumption and less chemical pollution, SFE could possibly perform better for the extraction for precious archaeological materials. The successful application of fatty acid stable isotopic analysis (FASIA) to the pigment binding media on the Terra-cotta Army of Qinshihuang indicates that it is an effective measure and will have great potentials in the studies of archaeological organic residues in the future.

Abstract:The stable sulfur isotope ratio of human (animal) bone collagen can be used not only to distinguish differences in individual food sources, but also to judge their migratory behaviors. Stable sulfur isotopic analysis has become more and more important with the development of bioarchaeology. Previously, its application was not common because the extremely low content of sulfur in collagen (there was no suitable standard material with low sulfur content for accurate testing), requirement of a large sample size for testing, and memory effects made the test more complicated. Failure of the accurate determination of sulfur content and its isotope ratio has been a limitation for the research on isotopic bioarchaeology. In recent years, a newly developed mass spectrometry (MS) technology has been able to determine the sulfur isotope ratio of bone collagen with a small sample size, but the difficulty in determining the sulfur content due to the lack of a low-sulfur content standard substance still exists. At present, we have not yet seen any reports on the methods specific to sulfur content and isotopic testing for archaeological bone collagen. In this study, we used an elemental analysis-isotope ratio mass spectrometry (EA-IRMS) with programmed ramping gas chromatograph (GC) for the determination of sulfur content and isotope values of collagen. Our instrumental parameter settings and testing procedure are provided in the text. Firstly, we used sulfanilamide and pasta reference material (PRM, 0.14% sulfur content) as standard substances for sulfur content determination. The standard curve established by PRM with different gradient masses was used to calibrate the international standard samples (USGS89 and USGS42) with a margin of error of lower than 0.1%, and a standard deviation of the sulfur content of the archaeological collagen samples within 0.02%. Then, we used the sulfur isotope values of the international standard samples (IAEA-S-1 and IAEA-S-2) to establish a linear regression curve by the two-point method, and corrected USGS42, whose δ³⁴S was available. The accuracy of the corrected δ³⁴S obtained was better than 0.3‰. Finally, we tested archaeological bone collagen samples and combined various factors, such as signal strength, sample mass, and instrument stability, and determined that stable isotope values obtained could be more accurate and stable when using a mass of 5 200-5 800 μg of collagen samples, with a standard deviation of δ³⁴S of lower than 0.4‰. Compared with the existing stable sulfur isotopic testing methods for collagen from various institutions around the world, the analytical method we established for the sulfur content and isotope ratio of bone collagen is also in the leading position. The application of this method in China will greatly promote the development of stable isotopic bioarchaeology, making sulfur isotopic analysis become one of the routine methods for isotopic analysis in the field of archaeology. This method is expected to better reveal the food structure and migratory behavior of ancient humans (animals) in China, and to explore important scientific and archaeological issues.

Abstract:Fumigation is currently a widely used method for rapid control of insect and mold diseases in cultural relics, but it also has problems such as weak desorption and easy secondary damage to cultural relics caused by residues. Focusing on three commonly used organic fumigants, this study has established a volatility detectionsystem based on the photo-ionization detection method. Using the Fick’s law, a prediction model for the volatilization rate of fumigants per unit area was established to accurately detect the residual amounts of fumigants. The results indicate that there was a good linear relationship between the mass fraction of organic fumigants and the sensor output value. The use of photo-particle sensors of the photo-ionization detector (PID) had good detection sensitivities for three organic fumigants—citronellal, citral and citronellol, with values of 2.072,1.287 and 0.702 V/(mg/L), respectively. The calculation results of the residue volatilization rate calculation model derived from the Fick’s law show that the correlation coefficient R² between the measured and predicted volatilization rates of the three organic fumigants was close to 1, and the significant difference P value approached 0. This model could be used accurately for the calculation of residue volatilization rates. In addition, it was found that under environmental conditions of 22℃, 60% (RH) and normal atmospheric pressure, and after complete fumigation of rice paper, the residual amounts of citral, citronellol and citronellal approached 0.1,0.06 and 0.01 ng/mm² after 5 hours of desorption, and all the residual amounts approached 0 ng/mm² after 72 hours of desorption. Therefore, the PID sensor and residue volatilization rate calculation model proposed by this study could accurately detect the residual amount and volatilization rate of fumigants used for paper cultural relics in practical applications, providing important new technical support and safety protection for the detection work for the fumigation and disinfection of paper cultural relics.

Abstract:In this study:silk fabrics of the Southern Song Dynasty and the Warring States Period were selected as the investigated objects; modern silk was taken as reference. The microscopic structure of the samples was observed by scanning electron microscopy, and thermogravimetric analysis was performed based on the principle of thermal analysis kinetics. The kinetic parameters of silk were calculated by applying Flynn-Wall-Ozawa, Kissinger-Akahira-Sunose and Kissinger models, and the relevant thermodynamic parameters were obtained. In this study, the thermal analysis kinetic method was introduced into the study of degradation of silk cultural relics, and the differences of the kinetic and thermodynamic parameters between modern silk and ancient silk were investigated. The thermal stability, degradation state and chemical properties of silk cultural relics were determined by the characteristic scale of activation energy, activation enthalpy and activation Gibbs free energy. This study has reference value for revealing the degradation mechanism and evaluating the degree of degradation of silk cultural relics, and also provides theoretical guidance for predicting the duration life of silk cultural relics.

Abstract:When the waterlogged beech cultural relics reinforced using the polyethylene glycol method are stored, they are susceptible to the combined effects of surrounding environmental factors such as temperature, humidity and light, resulting in the deterioration of cultural relics. In our work, Fourier transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM) and other methods were used to study the changes of microstructure of waterlogged beech samples reinforced by polyethylene glycol dehydration under the coupling of temperature, humidity and ultraviolet light. The results show that the saturated beech wood sample dehydrated and reinforced with polyethylene glycol had full cell morphology, and polyethylene glycol could adaptively be filled or adsorbed into various sizes of cell lumens and conduit pores, effectively maintaining the structure of the cultural relic sample. After 30 days of testing at 40℃ and 60% RH, the polyethylene glycol filled into the beech cells swelled and increased in volume, causing damage to the beech cell wall and continuous cracks between the cell structures. After natural drying, the polyethylene glycol underwent dehydration, contraction, and separation from the cell wall. The surface of the sample underwent yellowing, with a significant increase in brightness and a significant change in color difference after 30 days of testing in a coupled environment of 40℃, 60% RH, and 351 nm of ultraviolet light. Photodegradation led to the melting of polyethylene glycol, and the molten polyethylene glycol continuously precipitated, greatly weakening its reinforcement effect on cell walls; the polyethylene glycol precipitated from the beech wood gradually covered the surface of the sample, and the surface texture thus became sticky. Finally, an influence mechanism of coupling environment on the structure of beech wood reinforced using the polyethylene glycol method was proposed. This study could provide reliable guidance for the application of polyethylene glycol to the dehydration and reinforcement of waterlogged wooden cultural relics.

Abstract:A scientific way of conserving early oil paintings of China is discussed in this case study of Reduction of Rent and Interest. By exploring the artistic technique of the painting using the social historical approach and the comparative approach, we discovered that the painting was a mixture of Yan’an revolutionary realism, Western European academic classical realism and Soviet art plot techniques, reflecting that Chinese artists were in a state of preliminary exploration and not yet familiar with oil painting materials in the early 1950s. Through scientific analyses of morphology, constituents and properties of the painting materials, we found out that the deterioration was mainly attributed to the workmanship of the painting, especially the double-sided zinc oxide oil-based ground that the painter made. A protective restoration strategy was made, considering the special double ground layers of the painting. To conserve the authenticity and integrity of the painting, a new consolidation technique was applied onto the work. Accordingly, the painting has been reinforced and the original feature of the workmanship has been retained.

Abstract:Located in the middle reaches of the Glang-chen River basin, the Gad pa Ser rul Cemetery is one of the earliest tombs discovered in western Xizang. A large number of talc beads were unearthed from the tombs. In this study, a series of non-destructive analytical techniques such as gem microscopy, Raman spectrometry, X-ray diffraction, scanning electron microscopy-energy dispersive spectrometry were used, to obtain the chemical composition, phase structure and surface appearance of the talc beads. The results show that the disc-shaped perforated talc beads unearthed from the Gad pa Ser rul Cemetery were probably made of block talc after heat treatment. This work could provide important information for enriching the research data of early beading in western Xizang, and understanding the communication of ancient people in western Xizang and their social and cultural life.

Abstract:Cleaning is an important step in the conservation and restoration of ancient ceramics, and the removal of hard attachments on the surface is a technical difficulty. However, ultrasonic cleaning, steam cleaning and chemical cleaning have technical limitations. In this work, sand-blasting cleaning was carried out on different surface attachments of ceramic samples to scientifically evaluate the safety performance and cleaning effectiveness of this cleaning technology. Color difference analysis and microscopy were used to test and evaluate the effects of sand-blasting cleaning on ceramic samples. The results show that sandblasting cleaning was safe for the cleaning of porcelains but had certain damage on potteries and overglaze colors. Comparative tests were also carried out to evaluate the effectiveness of sandblasting cleaning, ultrasonic cleaning and steam cleaning on the cleaning of several kinds surface attachments at different parts of porcelains, including the body, glaze, cross-section and crack. The effectiveness of sand-blasting cleaning was thus verified.

Abstract:A bronze plate excavated from Xianrentai Burial M4 in Changqing, Shandong Province, exhibits distinct regional characteristics in terms of its shape and decorative details. The surface observation and X-CT analysis revealed a relatively more intricate casting process. The plate body was cast separately from both the plate legs and ears, and casting-on and welding techniques were employed for their joining. Compared to other bronze plates of the same period, the casting process of the Xianrentai bronze plate features a remarkable uniqueness reflecting the exceptional craftsmanship of its creator. This discovery and comprehension have also corrected the group preference in the related archaeological discussions of “seeing humans through materials”, thereby facilitating the realization of academic pursuits of “seeing humans through materials” from both “collective” and “individual” perspectives.

Abstract:The tomb of Eunuch Ma Yongcheng of the Ming Dynasty was excavated by the Beijing Municipal Institute of Archaeology from September 2014 to April 2015. A silver seal box was found in the niche on the north wall of the tomb, with a lock and a key attached to the box. The lock was hung on the box, and the key was placed in front of the box. In this study, X-ray diffraction, X-ray spectrometry, and scanning electron microscopy-energy dispersive spectrometry were used to analyze the composition and manufacturing process of the seal box. The results show that the seal box was made of a silver alloy with a lower copper content, and both its lid and body were welded with several rectangular hammered silver pieces. In addition, the box and its accessories such as the lock, the key and hinges were gilded. The results could provide new materials for understanding the technical characteristics of silver products in the Ming Dynasty. According to the study, silver boxes excavated from Ming tombs have different shapes and functions and were widely used in upper levels of society at that time. Metal locks unearthed from Ming tombs are mainly springlocks, mostly used for tomb doors, wooden boxes and treasure boxes, and the use of metal locks by the civilian class at that time was also common. The production of the seal box was related to Ma Yongcheng’s preference for and access to metal materials brought as a result of his employment experience.

Abstract:The mural tomb of Dong’er Village in Pucheng is one of the few Yuan Dynasty tombs fully-covered with complete mural paintings in Shaanxi Province. It is a valuable physical material for the study of the material culture and social features of the Mongol region during the confrontation period between the Song and Yuan Dynasties, and has extremely high historical and artistic value. In 2018, the mural tomb was relocated and protected as a whole. Multi-disciplinary studies and team work were critical for the full display of this precious cultural relic in the museum. To maximize the preservation of the murals and meet the needs of the public, through continuous verification and discussion, the display mode of the mural tomb evolved from segmented display, original-form display, and elevated display, to ultimately elevating the tomb and revitalizing the mural content. This approach has not only achieved a stable and controllable micro-environment for the tomb but also allowed the public to fully view the tomb murals and their revitalized content, thus resolving the conflict between mural preservation and utilization. The preservation and exhibition design of the murals were conducted simultaneously, supporting each other. After the main framework of the museum building was completed, the mural tomb was hoisted into its exhibition position for over a year of on-site preservation and display work. First, a temporary laboratory was set up on site, equipped with ventilation and air exchange systems. Then, the internal wooden keel support and plaster cloth support inside the murals, as well as the external cross steel framework used for hoisting were removed. Finally, the channel steel at the base of the murals was taken away, and the mural tomb was hoisted onto a 3 m-high custom steel framework. Following this, the surface of the murals was further cleaned, reinforced, and retouched. This process was time-consuming and coordinated with the exhibition work, including the installation of low-reflective glass, electrical wiring, and environmental control equipment at the base of the tomb. The exhibition of the mural tomb aims not only to present the historical information, artistic value, and social landscape of the tomb to the public, but also to promote new technologies for mural preservation, deeply explore the value of the murals, and revitalize their contents to enhance public understanding of cultural relics. The exhibition introduces the mural tomb and its scientific preservation through text and images, uses 3D models to visually demonstrate the on-site preservation process of the murals, and provides multimedia touch screens that allow the public to explore the mural details and content explanations through 3D virtual tours. Additionally, using 3D mapping curved projection technology, the preservation technologies and the tomb murals are animated and projected outside the tomb chamber, bringing the cultural relics to life and making the experience captivating. The mural tomb is exhibited in a closed environment, with real-time monitoring and control of the micro-environment within the tomb chamber. Monitoring data indicate that the environment inside the tomb chamber is stable and clean, which meets the requirements for the long-term display of the murals. Both LED and OLED light sources have been installed in the tomb chamber. According to comparative data measurements, the new OLED organic light sources emit less heat, offer better color rendering, and have a color temperature closer to 3 000 K, making them more suitable for the lighting requirements of the tomb murals. The management and maintenance of the mural tomb have been strengthened, including regular inspections of equipment, evaluations of the preservation status of the murals, and establishment of records and archives. The mural tomb harmoniously integrates the preservation and utilization of cultural relics, which has overcome the limitations imposed by its structure on exhibition viewing, and achieved the maximization of viewing perspectives, application of preservation outcomes, and comprehensive exhibition experience. This not only revitalizes the cultural relics and spreads the concept of cultural relic preservation but also provides a reference model for the conservation of similar mural tombs.

Abstract:The comparative tests of various properties of the calculus body of calcined ginger nuts before and after ultrafining with quartz sand were carried out. The structure, composition and morphology were analyzed using Fourier transform infrared spectrometry, X-ray diffraction and scanning electron microscopy. The applicability of the ultrafine powder of calcined ginger nuts in the process of reinforcing rock and soil cultural relics is discussed. The results show that, compared with normal calcined ginger nuts, the peaks of SiO₂ in the calculus body of calcined ginger nuts after ultrafining were weakened, and the those of CaCO₃ and Ca₂Al₂SiO₇·nH₂O were enhanced and sharpened, indicating that ultrafining was beneficial to the carbonization of Ca(OH)₂ and the hydration of SiO₂ and β-CaSiO₃. The hydration ratio, condensation time, shrinkage rate, moisture content and wave velocity of the calculus body after ultrafining were improved, and early compressive strength and flexural strength were increased. The water resistance, freeze-thaw resistance, stability and alkaline resistance of the calculus body after ultrafining were significantly improved. The calculus body after ultrafining had better adhesion and compatibility with tuff and red sandstone. In brief, ultrafining has not only retained the advantages of normal calcined ginger nuts but also given full play to the potential cementation properties of calcined ginger nuts. Therefore, the use of calcined ginger nuts after ultrafining is more suitable for the conservation and reinforcement of rock and soil cultural relics.

Abstract:In early October 2021, Shanxi was hit by heavy rainfall, and the rammed earthen walls on the west side of the Pingyao Ancient City, a world cultural heritage site, were damaged to varying degrees. To clarify the disease characteristics and development mechanism of rammed soil on the inner wall after being affected by precipitation, typical disease characteristic segments were selected for classification, statistics, and quantitative characterization. The types of rammed soil diseases mainly include cracks, sheet-like erosion, excavation, biological damage, and collapse. In addition, the engineering characteristics of compacted soil were obtained through indoor macro and micro tests, and statistical regression analysis was performed on the quantitative characterization results to obtain the mechanism of disease occurrence and development. It was found that 1) the formation of cracks was related to the plastic deformation caused by freeze-thaw cycles; 2) the occurrence of sheet-like erosion was negatively correlated with the content of clay particles; 3) the occurrence of excavation in the middle and lower parts of the wall was positively correlated with the content of soluble salts; 4) for collapse, one part was caused by the development and evolution of various diseases, and the other part was caused by the decrease in cohesion between compacted soil particles after rainwater infiltration. Finally, a disease framework system for the rammed soil on the west side of the Pingyao Ancient City was established, providing a scientific basis for its scientific conservation and targeted restoration and reinforcement.

Abstract:Identifying damage characteristics and analyzing damage degrees of ancient buildings affected by pests and diseases are crucial for developing maintenance strategies and preventive conservation measures for them. It is challenging to find insect adults or larvae on wooden components in surveys, hindering the identification and analysis of biological hazards. In this study, we focused on the examination of damaged wooden components within Longxing Temple, a nationally protected ancient building in Zhijin County, Guizhou Province, and analyzed and identified the causes of damage to the wooden components of this ancient building following several steps: identifying tree species, observing and analyzing surface and internal hazard characteristics, assessing degradation of three major components in wood, and identifying insect specimens. The results show that the wooden components were made from local Liquidambar species native to Guizhou, as determined by tree species identification. The pests caused elliptical wormholes on the wood surface ranging from 6 to 20 mm in length and from 3 to 6 mm in width. The internal cavities were filled with a mixture of powdered and granular wood chips and feces, extending flat along the wood texture. Furthermore, based on the analysis of damage characteristics, it was concluded that the wooden components were damaged by Eurypoda antennata. The analysis of wood composition in the feces show that E. antennata primarily degraded cellulose, with minimal degradation of hemicellulose and virtually no degradation of lignin. After surface and non-destructive internal testing analysis, it was determined that E. antennata caused a severe (Level 4) damage to the building’s wooden components. This study could provide valuable reference for identifying characteristics of biological damage in ancient buildings, and a scientific basis for the preventive conservation of ancient buildings.

Abstract:Scientifically and effectively evaluating the influences of historical temperature and relative humidity on organic cultural relics is the basis for optimizing the strategy of setting temperature and relative humidity in the storeroom, and balancing the effectiveness and sustainability of preventive conservation of cultural relics. Lifetime multiplier (LM) and preservation index (IPI) are advanced indexes which have been used to quantitatively evaluate the chemical degradation risk of organic cultural relics. Equilibrium moisture content (EMC) and response relative humidity (response RH) are advanced indexes which have been used to quantitatively evaluate the mechanical damage risk of organic cultural relics. We analyzed the reflection of the above indexes on the actual historical temperature and relative humidity in 29 storerooms, which have different temperature and relative humidity characteristics. The applicability of these indexes to evaluating historical temperature and humidity of organic cultural relic storerooms was studied accordingly. It was found: 1) LM could be used to evaluate the chemical degradation risk of organic cultural relics in a single media storeroom, and IPI was more suitable for evaluating the general chemical degradation risk of fragile organic cultural relics in a mixed-media storeroom; 2) EMC was a general index to evaluate the mechanical damage risk of organic cultural relics, and response RH could be used to evaluate the mechanical damage risk of organic cultural relics which had been adapted to its historical environment.

Abstract:The outdoor stone furnishings of the Forbidden City exist in various types and large quantities, but their preservation status is unsatisfactory, with some furnishings exhibiting serious diseases. Conducting evaluations of the preservation status of these cultural relics constitutes a prerequisite for effective conservation. In this study, we analyzed the disease conditions, physical properties, and related data of the stone furnishings of the Forbidden City to evaluate the overall preservation status of marble artifacts. On this basis, current evaluation methods for the preservation status of stone cultural relics were assessed, and a new evaluation method—the “average analysis method”—was proposed. Compared with the commonly used ones, this new method demonstrated higher accuracy in evaluating the preservation status of stone cultural relics.

Abstract:The lower reaches of Yangtze River are the birthplace of Chinese lacquerwares and an important production area with a wide-spread range. In our study, through the identification of 16 lacquerwares of the Han, Tang, Song and Yuan Dynasties in the lower reaches of Yangtze River, it was found that those of the Han Dynasties were mainly made of hard wood (broad-leaved wood), and those from the Tang Dynasty were made of soft wood (coniferous wood). This phenomenon was closely related to the change of social demand, progress of material understanding, and development of lacquerware-making technology. The constant change of lacquerware-making technology and the replacement of broad-leaved wood with coniferous wood made the fabrication process of lacquerwares easier and resulted in the change of cores from being heavy to light and from being thick to thin, bringing curving and diverse shapes. In addition, the lacquerwares with Quandietai also have different forms, which may be related to the type of lacquerware and the material understanding at different times. Based on the studies of lacquerware wooden cores, we understood the lacquerware-making technology and explored the development and utilization of ancient people’s knowledge of wood.

Abstract:China boasts a large number of precious paper-based cultural relics, but it is difficult to maintain their physical and chemical properties for a long time due to multiple internal and external factors. A variety of diseases can cause the decline of carrier performances, and these affect the lifetime of cultural relics. Most of the available studies of conservation and restoration focus on the analysis of the causes of paper acidification and deacidification materials, while those about the practical application are relatively fewer. Therefore, this article, from the practical level, takes the deacidification method as the research focus, and learns from the conservation and restoration experience of Italian paper relics. It introduces the preparations that should be done before deacidification and the selection of auxiliary materials, and sorts out several deacidification technologies commonly used indoors in recent years from the two perspectives of process and materials. It then clarifies the key points and precautions of operation and analyzes the advantages and disadvantages of different technologies. Finally, it proposes the working ideas for deacidification intervention based on the characteristics of paper-based cultural relics in China. In addition, in order to better keep the effect of deacidification, the article further discusses the significance and operation methods of the subsequent anti-oxidation and reinforcement restoration as an extension, to emphasize the importance of the overall conservation and restoration work.