Abstract:New and artificially-aged leather were adopted as the degradation reference samples for archaeological leather. A combination of technologies, specifically thermogravimetry-Fourier transform infrared spectrometry (TG-FTIR) and pyrolytic gas chromatography-mass spectrometry (Py-GC/MS) were employed as the analytical methods to study the degradation processes, mechanism and products of archaeological leather. The experimental results show that both the archaeological and the new leather samples undergo similar thermal degradation processes, which can be divided into two stages. Free water volatilization from the leather samples occurred in the first stage and thermal decomposition of collagen of the leather samples occurred in the second stage. The main chemical reactions during the thermal decomposition process include dehydration, decarboxylation, deamination, dehydrogenation and side chain cleavage of amino acids. The main products due to the thermal decomposition include water, carbon dioxide, ammonia, diketopiperazine, isocyanic acid, hydrocyanic acid, pyrrole and methane, etc. Besides, collagen, tannin and lipids of the archaeological leather samples were degraded or lost during the degradation process, resulting in their significantly lower relative percentages than those of the new leather samples. The combination of TG-FTIR and Py-GC/MS is a powerful method for studying the mechanism of degradation of archaeological leather. This combination can also be employed to evaluate the degree of degradation of archaeological leather.

Abstract:Due to its long history, the painting and the original mounting of Landscapes Inspired by Du Fu’s Poem are generally suffering from stains, fractures, cracks, corrosion and other diseases. After careful observation and analysis, part of the original mounting was cleaned, restored, but the rest of it was replaced. In order to prevent cracks, both mulberry paper and Xuan paper were used for mounting. Through restoration, the original mounting and historical information of the painting were retained, which is conducive to the long-term preservation, display and research.

Abstract:The combination of trace element and lead isotope ratio methods can complement the ability to trace bronze minerals. Previous measurements of the isotope ratio of bronzes in the cemetery of Guo State suggest that the bronze ore material may have originated at Zhongtiao Mountain in Shanxi and the middle and lower reaches of Yangtze River. The elemental analysis of this time shows that the trace elements of the bronzes are completely different from those of the Zhongtiao Mountain copper deposit in Shanxi, but have the same characteristics as those of the copper deposits and copper ingots from Tonglu Mountain in the middle and lower reaches of Yangtze River, and at ancient mining and smelting sites in southern Anhui. In addition, both trace elements and lead isotopes show that the bronzes of different tombs in the cemetery of Guo State share a consistent source of minerals, indicating that the source of bronzes unearthed from the cemetery of Guo State was relatively simple and stable.

Abstract:A pair of Mise porcelain bowls with lacquer decoration employing gold and silver inlay were unearthed from the underground palace of Famen Temple in 1987. They are rare and precious objects perfectly combining Mise, gold and silver inlay and lacquering crafts. A preliminary study of lacquering techniques was conducted through analysis of lacquer fragments using optical microscopy (OM), scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and infrared spectrometry (IR), in order to provide a reliable reference for the study of the history of science and technology, conservation and restoration, etc.

Abstract:Some typical jade artifacts excavated from the tomb of Changzikou in Taiqinggong town of Luyi County, Henan Province, were analyzed on site using several non-destructive analytical methods. The comprehensive physical and chemical information of jades, such as mineral phases, micro-morphology of decoration patterns, diameters and internal micro-marks of perforations and surface micro-morphology, etc. were obtained. Based on the analytical results, the material properties of jades and manufacturing techniques for decorative patterns, perforation drilling and polishing were determined. Combined with archaeological information, the relationships among materials, shapes, functions and manufacturing techniques are discussed.

Abstract:In order to discuss the corrosion mechanism of tin film, and prevent the efflorescence and fragments falling off Tin-coated pottery, microphotography, X-ray fluorescence and X-ray diffraction methods were used to analyze the tin. The film contained β-tin, α-tin, stannic oxide and stannous oxide. The corrosion mechanism of the tin film is discussed in combination with the test results. It was found that β-tin irreversibly turns into α-tin, with a lower density, below 13.2 ℃ and thus the volume expansion is the major cause of tin corrosion. Methods for the reinforcement and pasting back of tin film were selected and the treatment effect on two Tin-coated objects was good. In addition, according to the characteristics of Tin-coated pottery, some suggestions on preservation environment are also put forward in the paper.

Abstract:In order to study the composition, structure and status of preservation of polychrome potteries excavated from a Chu tomb of the Warring States period in Taoyuan County, Hunan Province, we used energy dispersive X-ray fluorescence (EDXRF) spectrometry, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) and laser Raman spectrometry (LRS), etc. to analyze the chemical compositions of pottery bodies and pigments on pottery surfaces and metal coatings. The chemical compositions of pottery bodies, which are made from fusible clay, are similar. The red pigment on pottery surfaces is cinnabar (HgS) and the black is carbon black (C). According to the SEM-EDS and XRD analyses, a layer of tin, as a typical decoration, was identified on pottery surfaces. By Fourier transform infrared (FTIR) spectrometry, the black material on the inner side of the tin layer is mainly lacquer, along with other types of binding materials. This paper provides new data for future research on the craftsmanship and development of tin-decorated pottery during the Warring States period.

Abstract:The cleaning of hard surface attachments, crevice contaminants and fracture contaminants is a technical difficulty for the conservation of unearthed porcelain. Current mechanical, chemical, ultrasonic and steam cleaning methods have their respective limitations. In this research, micro-nano bubble cleaning was applied to unearthed porcelain from Qinglong Town, and its safety performance and cleaning effectiveness were evaluated. Colorimetric, gloss and microscopic analysis of the glaze and microscopic measurement of crevices were used on the Qinglong Town samples and imitated porcelain samples, and showed that micro-nano bubble cleaning was a safe technique. Micro-nano bubble cleaning was compared with ultrasonic cleaning and steam cleaning so as to evaluate the effectiveness of cleaning of surface attachments, crevice contaminants, fracture contaminants and sites of metal erosion, and showed that micro-nano bubble cleaning was an effective method.

Abstract:At present, the push-rod thermal expansion method is most widely used in determining firing temperatures of ancient ceramics. Through review of the research status of this method and application to ancient Chinese pottery, white porcelain and black porcelain, we analyzed their thermal expansion curve characteristics in detail. In combination with simulation experiments on high-iron bodies, it was proposed that firing temperature analysis should be carried out from three types: low-temperature pottery (below 800 ℃), high temperature pottery (above 800 ℃) with obvious shrinkage turning points, and high temperature pottery with no shrinkage but only expansion turning points at high temperatures. Using a tangent line to calculate the firing temperature has higher accuracy only in the case of shrinkage turning points, and the temperatures of expansion turning points can be used only as references. At the same time, the characteristics of raw materials should be studied from the aspect of chemical composition using a relatively complete sintering step curve and verified by combining physical performance indexes such as water absorption rate and the like. These results provide a reference for further applications of this method.

Abstract:The firing temperature of ancient bricks determines their physical and mechanical properties. This paper proposes a new method to determine the firing temperature of ancient bricks based on magnetic susceptibility. By reheating ancient bricks, the magnetic susceptibilities of the ancient bricks at different temperatures were measured, and a magnetic susceptibility change-rising temperature figure was thus obtained. The first large deviation in the figure is the firing temperature of the ancient bricks. Using this method, the estimated firing temperatures of clay bricks that were fired at actual temperatures of 700 ℃, 800 ℃ and 900 ℃ were obtained: 690 ℃, 810 ℃ and 870 ℃, respectively. The small difference between the estimated and the actual temperatures proved the feasibility of the proposed method in determining the firing temperatures of bricks. In this paper, the firing temperatures of 10 ancient bricks in Pingyao ancient city were determined using this method. It was found that the firing temperatures were in the range of 650 ℃~690 ℃ and 850 ℃~870 ℃. Based on this, it is speculated that ancient bricks of Pingyao ancient city were heated by burning straw and firewood. The experimental results of this study could provide a theoretical reference for restoration and conservation of ancient buildings.

Abstract:Dharma Valley Buddhist Temple is an important Buddhist site in Khotan area of Xinjiang. It boasts a high value of Buddhism and art, having presented a significant influence on Buddhist arts of China and even East Asia. In order to study the pigments and workmanship of wall paintings excavated from Dharma Valley Buddhist Temple ruins in Xinjiang, cultural relic fragments that cannot be restored were specially selected as samples. Wall painting samples were analyzed by stereomicroscopy, X-ray fluorescence spectrometry, X-ray diffractometry, Raman spectrometry and polarized light microscopy. The results show that the blue pigment is lazurite, the green pigment is atacamite, the white pigment is gypsum, the red pigment is cinnabar, the brown pigment is iron red and the ochre yellow pigment is ferrite yellow. This study provides an important scientific basis for the further exploration of the history of ancient arts and crafts and subsequent restoration and conservation.

Abstract:In order to scientifically analyze the composition of the black pigment on the west wall at the Eastern Gate Tower of Han Yang Mausoleum and further discuss the usage of pigments in Han imperial mausoleums, we adopted super depth field microscopy, scanning electron microscopy and energy dispersive spectrometry (SEM-EDS), map scanning technologies and X-ray diffraction (XRD), as well as a reference to relevant literature to make scientific analysis and in-depth discussion. The results show that the black component is copper oxide, which was caused by the oxidation of the original copper-containing blue-green pigment. This paper provides a scientific basis for subsequent pigment identification of painted cultural relics. That is, not only were modern analytical and testing means used to analyze and identify pigment species in their current state, but also it is pointed out that their color presentation forms are scientifically based on the environmental changes of the cultural relics. In addition, the map scanning of SEM-EDS technology can clearly identify the distribution of pigment particles, so it has incomparable advantages in microscopic analysis of pigment particles.

Abstract:Long-term exposure to natural environment and presence of a great number of contaminants has resulted in the loss of the glaze layer of glazed tiles on ancient buildings, which seriously affects the appearance and artistic value as well as subsequent conservation and restoration. In our study, contaminants on glazed components were detected in experiments; the results indicated that the main contaminants were black carbon-containing attachments and old repair materials. Laser and steam cleaning technologies were used to eliminate these contaminants, and the cleaning effects were evaluated using video microscopy and colorimetry. The results show that 1) laser cleaning could effectively remove black carbon-containing attachments; 2) steam cleaning had significant effects on the removal of surface dust and light black contaminants; 3) removal with a surgical blade was effective for old repair materials. The experiment could play a guiding role in the process of cleaning and conservation of glazed components.

Abstract:Preventive conservation requires suitable and stable temperatures and relative humidity (T & R.H.) in a museum environment. This paper is about research on a new evaluation method for T & R.H. stability. Museum environment monitoring data of temperatures and relative humidity were converted into spectrum maps using fast Fourier transform, and the T & R.H. stability was analyzed by the interpretation of the spectrum maps. The merits and demerits of spectrum maps of T & R.H. were analyzed in detail, and the fluctuation characteristics and the stability of T & R.H. in exhibition halls and showcases as well as the control effect were evaluated by the interpreted spectrum maps. This paper provides a new and effective method for evaluating the T & R.H. stability of a museum environment.

Abstract:In order to better understand the shaping features of Neolithic tube-shaped pots from Liaoxi area, 595 tube-shaped pots with detailed size information were selected from archaeological excavation reports for further analysis. The characteristics in shaping are described from three aspects, i.e. mouth, abdomen and decoration. Through quantitative analysis on the structural relationship between caliber and bottom diameter and that between caliber and height, it was shown that during each cultural period, a certain rather stable proportional relationship in structure was followed. Moreover, the shaping features of different cultural periods are obviously different.

Abstract:The stretch of paper in the process of soaking and drying is an important index that affects the performance of paper used for ancient book restoration. In order to reduce the stretch rate of newly-made restoration paper, six kinds of restoration paper samples were treated with the hygrothermally-accelerated aging method, and the influence of the aging process on paper stretch was determined and analyzed. The results show that the hygrothermal aging can significantly reduce the stretch of paper, especially the lateral expansion rate and dry shrinkage rate. A short period of hygrothermal aging can reduce the stretch rate of newly-made restoration paper to a level close to that of old paper.

Abstract:Subashi Buddhist Temple used to be an important node connecting China and foreign countries along the ancient Silk Road. The study of unearthed objects from this site can provide a significant reference for the analysis of the exchange and integration of Chinese and foreign cultures and the circulation and prosperity of trade along the Silk Road. In our study, we used X-ray photography, X-ray fluorescence spectrometry, ultra-depth 3D video microscopy, X-ray diffraction, scanning electron microscopy and other scientific and technological analysis methods, as well as relevant literature, to discuss the functions of two metal products unearthed from Subashi Buddhist Temple. It was preliminarily determined that one sample was used to poke copper coins in West Turk and it has been speculated that the other sample was a silver-like metal product and that natural aluminum was applied on the surface. The analytical results provide an important reference for studying the economic and cultural exchanges between the countries of the Western Regions along the Silk Road during the Sui and Tang Dynasties and also those between the Central Plains and the Western countries.