Abstract:Excavation of Cave 3, the largest-scale cave excavation of Yungang Grottoes, came to an abrupt end during the process. The special structure and natural weathering over thousands of years have resulted in a variety of diseases, among which collapse of the back room roof is the most serious. By means of rock testing, physical exploration and borehole exploration, the causes of roof failure were discovered. The roof has been strengthened by measures such as grouting of cracks and insertion of anchor rods subsequently. The analysis of cracks, tilt and stress monitoring data for 121 days after completion shows that the reinforcement is effective and it has extensive reference significance.

Abstract:The first Wengzhong (stone grave statue) on the east side of Qianling Mausoleum has many diseases, but cracks are the primary factor that endangers its safety. Through on-site investigations, we determined the crack distribution characteristics of the first Wengzhong on the east side and also analyzed its stability. The results show that there are five cracks affecting the stability of the stone carving, two of which are through and three of which are partially through. The cracks divide the stone carving into five blocks. The center of gravity of the central block has moved forward, and has become, at present, the main power source leading to the instability of the stone carving. The heel block is the key block for the stability of the stone carving. At the same time, there are many secondary cracks, indicating that the object is in an unstable state. The stone carving may suffer from overall collapse in case of failure of steel belts, complete penetration of cracks and earthquakes; therefore, reinforcement and prevention measures are needed. These results can provide a scientific basis for the conservation of the first Wengzhong on the east side of Qianling Mausoleum.

Abstract:Carved during the Northern Dynasties era, Luohan Grottoes are an important part of the 100-li (31-mile) Jingchuan Grotto Corridor. As an important historical and cultural heritage site on the ancient Silk Road, the murals of the grottoes boast rich content and special techniques, which are of great value for research on the development of Buddhism in Jingchuan and the civilization of the Silk Road. We have analyzed the materials and structural features of the murals. The results show that the structure of the murals from inside to outside is support, coarse plaster (straw added), fine plaster (cotton added), white ground layer and paint layer. The murals were painted many times. For interior murals, the red pigment is cinnabar, the green is atacamite and the blue is azurite. For exterior murals, the red pigment is red iron oxide, the green is emerald green, the blue is ultramarine, the orange one is yellow iron oxide and the black is carbon black. The workmanship of the murals is explained and the application of mural pigments is compared with that of other murals along the Silk Road, in order to promote the conservation and utilization of this cultural heritage.

Abstract:Three saints of Avatamsaka—Sakyamuni, Manjusri and Samantabhadra—of Caoxi Temple in Yunnan Province are remarkable wooden statues of the Dali Kingdom (937—1253). They were exquisitely made and show solemn states. In our study, X-ray radiography, a non-destructive technology, was undertaken to investigate the techniques of their manufacture, historical conservation marks and their condition of preservation. The results provide a deeper understanding of the three saints and a considerable reference for the future conservation work. This work also demonstrates that X-ray radiography is a non-intrusive and efficient method for the study of ancient wooden statues of large size.

Abstract:The Bronze Galloping Horse and the Bronze Chariot and Horse Guard of Honor of the Eastern Han Dynasty, unearthed in Wuwei, Gansu Province, are rare masterpieces of ancient bronze artworks in China. They are representatives of cultural relics in China and symbols of ancient Chinese civilization. Recently, Gansu Provincial Museum found, using modern scientific testing instruments and comprehensive analyses, that the Bronze Galloping Horse and the Bronze Chariot and Horse Guard of Honor were not cast with wax-lost method, but, rather, the pottery model casting method. The Bronze Galloping Horse has legs which were inlaid with iron tenon core bones for a stronger support. Among the Bronze Chariot and Horse Guard of Honor, bronze horses of type A and those of type B (with inscriptions) are two batches produced with different casting processes. These findings provide new materials for further research on the Bronze Galloping Horse and the tomb owner.

Abstract:A portion of a silk calligraphy scroll was restored recently at Shanghai Museum. The surface of the silk is covered with a red coating, and there are hand-painted patterns such as cloud patterns, bat patterns and “Shou” (寿) character patterns. In order to protect the scroll, non-destructive (micro damage) detection technologies such as video microscopy, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), Fourier transform infrared (FTIR) spectrometry, Raman spectrometry and hyperspectral imaging were used, prior to restoration, to identify the materials and processing methods used. The results show that little of the silk used for this scroll remains. After mounting a layer of paper on the back, the silk surface was painted with lead white, and then cloud and bat patterns were drawn with kaolin and silver powder. Also, the fuzzy seal was effectively extracted. The study provides a scientific basis for subsequent conservation and restoration.

Abstract:Alum is one of the most important materials in the restoration of calligraphy and paintings. However, easy hydrolysis of alum produces acid at high humidity, which can accelerate the hydrolysis and aging of paper cellulose. The pH value, hydrophobicity, color difference and mechanical properties of Xuan paper and color fixing before and after sizing with alum as well as six precipitants with high cationic charges (after hydrolysis) were studied. The surface condition after sizing, including the chemical bonding of precipitants with gelatin and fibers, were tested by scanning electron microscopy (SEM) and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometry. Also, the species distribution of precipitants after hydrolysis, mixing with glue and sizing on the surface of Xuan paper were studied using high-field ²⁷Al-nuclear magnetic resonance (²⁷Al-NMR) spectrometry. The results show that the pH value of Xuan paper sized by white polyaluminium chloride(PAC) could reach over 7 and the sizing material improved the hydrophobic property and mechanical strength of the paper and made pigments that have good color and no shading. SEM analysis shows that white PAC could cover and fill fibers and pores of Xuan paper uniformly. ²⁷Al-NMR, ATR-FTIR and a curing test show that the content of [AlO₄Al₁₂(OH)₂₄(H₂O)₁₂]⁷⁺(Al₁₃) in PAC was relatively higher, and it also had the effect of promoting the drying of gelatin. It could be bonded with gelatin to form a network complex, which was suitable to replace alum as a sizing precipitant.

Abstract:With the development of non-destructive and micro-destructive testing technologies, micro-analysis of paper used in archives has been increasingly applied. At present, the most commonly-used method for paper fiber observation and detection is the staining method in conjunction with optical microscopy; however, this method depends greatly on the quality of staining agents. Polarized light microscopy can be used without staining fibers and thus provides a better way for fiber identification from the perspective of fiber morphological characteristics. By reviewing the related research on the application of polarized light microscopy in the detection and analysis of paper, it is found that the current research on the fiber detection of paper by this technology is still in the stage of theoretical analysis and lacks practical applications. Observation and analysis of the fiber morphology and other components of paper used in Mustang archives using polarized light microscopy illustrate the effective application and the unique advantages of this method for the observation and identification of paper fibers used in archives and for the distinguishment between fibers and other cells or crystals in papermaking pulp.

Abstract:Since the Quanzhou Bay Song Dynasty shipwreck was buried in a marine environment for more than 700 years, the physical and chemical properties of wood have been changed and there is a large amount of salt in its hull. The special state of the shipwreck is thus different from that of usual wooden relics, so it is very necessary to carry out a study of suitable preservation conditions for the hull. In view of the special state of preservation of the shipwreck, a series of experiments was carried out, including a salinity stability test, observation and analysis of moisture content and dimensional stability of different wood samples under different humidity conditions and the impact of temperature changes on the woods. Based on the results of these experiments and considering factors such as energy economy and the climate in Quanzhou region, it is concluded that 1) the upper limit of temperature in the exhibition hall should be 27 ℃ in summer and 25 ℃ in the rest of the year; 2) the relative humidity should be controlled between 50% and 60%, and the change range is safe and reasonable should the extent of variation be kept within 5%.

Abstract:Wooden artifacts excavated at Jianchuan County in Yunnan Province, China, were investigated to better understand the degradation aspects of waterlogged archaeological woods. Excavated Yunnan pines (Pinus yunnanensis) have been deposited in the mud soil for more than 4,000 years. Degradation occurred mainly to latewood tracheids but degradation in latewood was not uniform:intact tracheids were also present among the severely degraded ones. The results of transmission electron microscopy (TEM) show that 1) degradation started at the interface between S1/S2 and S2/S3 layers; 2) secondary cell wall layers were all degraded in the advanced stage of decay, leaving only compound middle lamella; 3) erosion bacteria were found be responsible for degradation of waterlogged archaeological Yunnan pines. However, soft rot cavities were not found in these samples. Solid state nuclear magnetic resonance (NMR) data coincided with degradation patterns, showing the preferential degradation of cellulose and hemicelluloses, whereas lignin polymer showed resistance. Degradation patterns of the waterlogged archaeological Yunnan pines were similar to those of the wooden artifacts which were excavated from wet environments.

Abstract:The common harmful residues found in animal specimens are mainly due to taxidermy, conservation and the environment. In order to clarify the situation, Guangdong Museum (GDM) used energy dispersive X-ray fluorescence (ED-XRF) and inductively coupled plasma-optical emission spectrometry (ICP-OES) for analysis and then found that 1) both feather and hair of specimens in GDM contain sulfur (S), calcium (Ca), arsenic (As), chlorine (Cl), potassium (K), aluminum (Al), iron (Fe), silicon (Si) and zinc (Zn), etc. using ED-XRF to detect elemental compositions; and 2) mammalian and large raptor specimens have higher amounts of trace elements such as iron and zinc. Under normal conditions, arsenic, which is toxic, adheres to the surface and inside of specimens for a long time, affecting both keepers and the environment. Thus, it is recommended that arsenic compounds be prohibited in taxidermy.

Abstract:A Zhen’an Temple iron bull has serious corrosion problems; furthermore, the mechanism of corrosion is complex. We tried to clarify the type of corrosion products of the iron bull and the factors influencing the corrosion, in order to provide a basis for its subsequent restoration and conservation. Scanning electron microscopy (SEM), X-ray diffractometry (XRD) and laser confocal Raman spectrometry were used to analyze the phase composition and rust layer structure of the surface corrosion products of the iron bull thus to understand the mechanism of corrosion. The results show that 1) the belly of the iron bull is hypoeutectic white cast iron, and the iron bull structure contains various phases and inclusions, which reduces its corrosion resistance; 2) the surface corrosion products of the iron bull exhibit serious delamination; the outer and inner corrosion products are dense, with the main components being goethite and Fe₃O₄; 3) the corrosion products in the middle layer are relatively loose, the main components of which are lepidocrocite and hematite; 4) the corrosion products of the ear, left foot and tail of the iron bull mainly contain goethite, lepidocrocite, Fe₃O₄ and hematite, etc.; goethite has the highest content in the rust products; 5) there are obvious differences in the compositions of the corrosion products of different parts of the iron bull—the ratio of goethite to lepidocrocite of the corrosion products of the ear is the smallest while that of the left foot is the largest. The factors influencing the corrosion and mechanism of corrosion of the iron bull were then analyzed.

Abstract:Temperature and humidity are two of the most important factors that influence the preservation of cultural relics. It took seven months to get continuous test data from an airtight showcase in Emperor Qinshihuang’s Mausoleum Site Museum. The results show that the internal temperatures of the showcase fluctuated with the change of external temperatures and that the stability of humidity depends on the air airtightness and difference in relative humidity between inside and outside of the showcase. Good airtightness could effectively reduce interference of ambient humidity. A short-term fluctuation of internal relative humidity of an airtight space was mainly affected by environment temperatures, so good control of temperature could effectively reduce the fluctuation of relative humidity.

Abstract:In the information society, museums have an active responsibility to share knowledge with the public. Museums use information technology to manage collections and related data to meet the needs of both daily business and users in the web environment. Presenting information about cultural objects in the Internet environment requires standardized metadata schemas and controlled vocabularies to describe the core information of objects. This study illustrates the definitions and types of data standards, and explains the concept and function of descriptive metadata for cultural objects. The author compared the metadata schemas of CONA, CDWA Lite, Object ID and the first National Movable Cultural Objects Survey to show how different metadata schemas influence the retrieval results. Another comparison was based on the online collection retrieval mechanism of four museums. The retrieval results also indicated that reasonable metadata structure and indexing with controlled vocabularies are critical for accurate searches. Finally, it is recommended that any local museum’s information system should formulate standardized descriptive metadata schemas for cultural objects with supporting cataloguing rules and locally controlled vocabularies, and that the online collection retrieval should consider users’ needs and present complete cataloguing results.

Abstract:As a kind of emerging protective material, hydroxyapatite has been widely studied and applied in the conservation of limestone, calcareous sandstone and bone relics. In this paper, the characteristics of hydroxyapatite are described, and the application and mechanism of conservation of apatite are introduced. Significant references and the directions of development of hydroxyapatite protective materials are also discussed.

Abstract:The starting point of the Silk Road lies in China/East Asia, and China plays an important role in the development of the Silk Road. There are many kinds of ancient textile relics, and commonly-used research methods for the scientific analysis of textile include chromatography, spectrometry and mass spectrometry. Here, we systematically describe existing analytical technologies for textile fibers (e.g., scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and fiber optic spectrometry) as well as methods for textile dye analysis (e.g., thin layer chromatography (TLC), high performance liquid chromatography (HPLC), Raman and fiber optic spectrometry). For textile fiber identification, SEM and FTIR methods are more reliable. For the analysis of textile dyes, the accuracy and sensitivity of the HPLC method is more recognized. Raman and optical fiber spectrometry have advantages of in-situ and non-destructive characteristics and have been paid more and more attention to the study of textile cultural relics. This paper summarizes the principles, characteristics, research progress and developmental potentials of these methods in the analysis of ancient textiles, and could provide references and scientific support for the research on the conservation of textile cultural relics.