Abstract:Starch grain analysis of human dental calculus offers a direct link to consumption of plant foodstuffs by ancient peoples. The Peiligang Site is an important middle-Neolithic archaeological site in central China. Five teeth from two adult skeletons excavated from graves M2 and M5 in 1977 were examined. Thirty-eight starch grains were extracted from the dental calculus of these teeth. Four of those starch grains could not be identified because of damage. The others were classified into six groups. More than half of the grains were from acorns (Quercus sp.), beans, roots or tubers, Triticeae Dumort and Coix spp., and some were probably from common millet (Panicum miliaceum L) and foxtail millet (Setaria italica L. Beauv.). Starch grains from the human dental calculus at Peiligang Site indicate that ancient human foodstuffs might have been sourced primarily from gathered wild plants. In light of this investigation as well as archaeobotanical research on other Peiligang Cultural-related sites, it could be inferred that a wide-spectrum subsistence economy might have existed 8000 years ago in central China.

Abstract:Composite organic-inorganic hydrophobic silica films were made by the sol-gel method using tetraethyl orthosilicate (TEOS) and methyl triethoxysilane (MTES) as the precursors, a little n-octylamine as the catalyst, and polydimethylsiloxane (PDMS) (method 1) or silane coupling agent KH570 (method 2) as the organic modifier. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and water contact angle (WCA) were used to analyze the chemical components, surface morphological structure and hydrophobicity of silica films on brick surfaces. The reinforcement effects on the bricks were verified by testing their variations in appearance, water absorption and porosity before and after being reinforced. The result shows that silica sol with -CH₃ group could be obtained using both of the two methods. In addition, the water contact angles treated by both methods (method 1:mass ratio of PDMS to the precursors is 10%; method 2:mass ratio of MTES to TEOS is 2) exceeded 140. The capillary water absorptivity was reduced to 1~2% the rate for the untreated bricks, while the color difference and gloss was little changed for the reinforced bricks. However, the conservation effect of method 2 is better than method 1 in terms of weathering resistance according to a relevant test, indicating that the hydrophobic silica films synthesized by method 1 should be selected as the reinforcement material for bricks.

Abstract:In archaeological excavation sites, it is often difficult to extract extremely fragile cultural relics and move them to laboratories. First of all, cultural relics must be reinforced temporarily before being relocated. In recent years, new revolutionary types of volatile solid materials for temporary reinforcement, such as menthol and cyclododecane, etc., have been successfully applied in some excavation sites. However, there are still some issues to be addressed. For example, can these materials be used in highly moist archaeological sites? How is their working performance？ In this study, in terms of the working properties of the materials, and the construction technology and safety of cultural relics, menthol, coumarin, ethyl maltol and cyclododecane were selected as materials for study in a small field experiment carried out at the Liangzhu work station of the Cultural Relics and Archaeology Research Institute of Zhejiang Province. This work could serve as a reference for archaeological or conservation workers who wish to select suitable temporary reinforcement materials to extract extremely fragile cultural relics in moist excavation sites.

Abstract:Ancient buildings are important non-renewable objects of cultural heritages with great cultural and economic values. Therefore, conservation and protection of ancient buildings is very necessary. Ancient Chinese buildings were mainly made of wood. Due to the low fire resistance rating of wooden structures, ancient Chinese buildings have always been faced with a great hidden danger-fire-so research on the performance of fireproofing for the wooden components of ancient buildings is extremely urgent. Three different types of wood and five different types of flame retardant were selected as research objects. The woods were characterized by thermogravimetric analysis and scanning electron microscopy (SEM). Then various mechanical properties of the woods were tested. The results show that the performances of the woods sprayed with flame retardants are better than those of the woods without spraying. In particular, heterocyclic organophosphorus or phosphorus-nitrogen flame retardants could be used for unpainted wood components, phosphorus-nitrogen flame retardants are suitable for ordinary painted wood components and phosphorus-nitrogen flame retardants or flame-retardant oils are applicable to wooden components processed with tung oil.

Abstract:To effectively protect ancient Chinese buildings, the seismic performances of ancient Chinese buildings of the Ming and the Qing dynasties were studied by shaking table tests. A 1∶2 reduced-scale model of an ancient building from the Forbidden City and having a single layer gable and a hip roof was built. The model possessed all features of the real building, including free-standing columns, beams and column frames, tou-kungs (bracket set), a roof, filler walls and so on. The construction of the model also accords with the relevant construction rules for ancient Chinese buildings. Using white noise excitation, the dynamical characteristics of the model were obtained. Then the 1940 El-Centro earthquake waves of different intensities were applied to the model. Seismic responses such as displacement, acceleration and shock mitigation coefficient ratio, etc. of the model were studied. Seismic performances of the constituents such as the free-standing column roots, the tou-kungs, the mortise-and-tenon joints, the roof, etc. are also discussed. Results show that under the action of earthquakes, the main mode shape of the model is that of a level torsion pendulum, which relates closely to the uneven mass of the roof. The basic frequency of the model before the shock was 1.47Hz and the damping ratio 4.6%. The response curves of its displacement and acceleration were nearly even and stable, reflecting the good seismic performance of the model. Although the roof magnifies the earthquake forces to some extent, the other constituents such as the free-standing column roots, the tou-kungs and the mortise-and-tenon joints could mitigate the response of the model. The order of shock mitigation capability of the different constituents was:mortise-and-tenon joint > tou-kung > free-standing column root. The shock mitigation coefficient value of mortise-and-tenon joint could decrease to 0.30, the value of the tou-kung to 0.53 and that of column root to 0.66. The filler walls collapsed in the earthquakes, but that did not affect the stability of the whole structure. Thus ancient Chinese buildings with single layer gables and hip roofs have good seismic performance.

Abstract:Lingzhao Xuan in the Forbidden City is one of the oldest steel-masonry composite structures in China. The building has very important historical, artistic and scientific value. In order to evaluate the structural safety of the building under earthquake conditions, we set up a three-dimensional finite element model to analyze its dynamic properties and earthquake response in order to obtain natural frequencies, modal modes, the earthquake displacement response and the earthquake stress response. The results show that the structure of Lingzhao Xuan is very symmetric and its torsional rigidity is large, which is better for the seismic behavior of this building. Under conditions of 8-degree frequently occurring earthquake, 8-degree fortification earthquake or 8-degree rarely occurring earthquake, the maximum displacement and the maximum story drift of the building can meet the requirements of the present codes, and the maximum compressive stress of this building is lower than that of the masonry, so the building has no fracture failure. Under conditions of 8-degree frequently occurring earthquake or 8-degree fortification earthquake, the maximum tensile stress of this building is lower than that of the masonry, so the building has no cracking failure. However, under conditions of 8-degree rarely occurring earthquake, the maximum tensile stress of some parts is larger than that of the masonry, and these position will have cracking failure. Finally, the seismic strengthening strategy of this building is presented based on the results of the dynamic properties and seismic behavior analysis.

Abstract:A pig-shaped bronze You (a bronze wine vessel) of the late Shang Dynasty at the Shanghai Museum has a unique style and delicate decorations. However, the You is damaged with a missing part as large as almost half of the whole surface. In order to restore the original appearance of the vessel, I made improvements on the traditional integration method through mold-making from the original part. By tailoring and adjusting the mold-cast resin pieces for integration, I overcame the problem that there is usually a small difference in the decorations and shapes between the resin and the original bronze part. The improved method has not only been effective in the restoration of the pig-shaped You, but also demonstrates a new solution and methodology for the integration of other bronze objects.

Abstract:The study of a binaural bronze Zeng of the Eastern Han Dynasty in Guiping Museum is of importance for research on the development of bronze smelting and casting technology in the Guangxi area. However, having been kept in the local moist environment for a long time, the bronze Zeng has serious mineralization. Restoration of the object and improvement of its conservation conditions is extremely urgent. In this paper, X-ray images, optical microscopy, scanning electron microscopy, energy spectrum analysis and simulation experiments were used to study the casting process, the alloy composition, and the corrosion products of the Zeng. The results show that the bronze Zeng were formed by integral casting. The technologies of the wheel system, scraper and after-casting engraving were used in the process. The ring foot of the model was cut to make a mould for the part of the grate. Based on our findings, we followed the principle of minimum intervention and strove to combine the traditional cultural relic restoration methods with the modern restoration concepts. We used several conservation and restoration measures such as rust cleaning and repair, not only to improve the overall stability of the bronze Zeng, but also to meet display requirements and to explore its potential value as a cultural relic.

Abstract:By virtue of the excellent skills and wisdom of artisans, our ancestors turned soil into “gold”, making Chinese ceramics a great and famous contribution to the human civilization and culture. However, many fragile ancient ceramics have suffered irreversible damages over the past long years of the history, causing great losses. In this paper, the author summed up his 20-year experience in terms of restoring ancient ceramics and made a comprehensive comparison of various methods of replication and restoration to provide a reference for the safe and effective restoration and replication of different types of ancient ceramics.

Abstract:Twenty-two gilt metal objects and gold and silver wares dating back to the Northern Qi Dynasty were unearthed from the Han Zunian Tomb in Taiyuan, Shanxi Province in 1982. I used microscopy and X-ray fluorescence, two nondestructive methods, to study these relics. I found that (1) the gilt bronzes were formed by casting and then were surface-treated using heated gold amalgam and (2) the technology and the style of the gold and silver wares were influenced by the cultures of Xiyu (or the Western Regions, including what is now Xinjiang and parts of Central Asia). The research results provide important scientific information for the comprehensive understanding and further study of metal-ware technologies of the Northern Qi Dynasty.

Abstract:After long-term monitoring of the microenvironment at the Tanjiapo Site Museum of the Tongguan kiln Site, we compared and analyzed the data on air temperature, relative humidity, soil temperature and soil moisture content to evaluate their patterns of variation and characteristics in order to get a preliminary understanding of the environmental conditions at this historical site. The results indicate that the damp and rainy weather conditions caused high temperatures and high humidity inside the Tanjiapo Site Museum of the Tongguan Kiln Site and its earthen site. The site was prone to suffering greatly from erosion due to underground water, which resulted in direct or indirect diseases and accelerated physical and biological damage to the earthen site. We proposed to control the site environment scientifically and properly, to set up an environmental database and to form a set of integrated forecast and alarm systems.

Abstract:In order to better conserve, protect and use paper documents and lengthen their lifespans, we reviewed the influences of acid-base properties of paper, relative humidity, temperature, light, air contaminants and microorganism on the aging of paper, and the mechanisms and effectiveness of mitigation measures. The acid-base property of paper has a great influence on its aging:the more acidic the paper is, the quicker the aging will be. Therefore, paper documents should avoid exposure to acidic materials, and severely acidified ones should be de-acidified. Relative humidity has a two-way influence on paper aging. The aging of paper becomes quicker with the increase of relative humidity. However, physical damage, such as embrittlement and warp, will occur to paper when the relative humidity is too low. Furthermore, fluctuation of relative humidity is more harmful than undesirable values. The optimum relative humidity range for paper document conservation is 40%~60% where steady values are easy to reach and maintain all year round. The rate of aging of paper also increases with the rise of temperature. The optimum temperature for paper document conservation is around 20℃. In addition, fluctuation of temperature will cause variation of relative humidity, and therefore temperature stabilization is also important. The aging of paper can be severely accelerated by light, and the damage can accumulate. Ultraviolet rays can cause the strongest damage to paper, while infrared rays can induce heat effects. Therefore, paper documents have to be kept out of sunlight. Lamps with ultraviolet or infrared rays should not be used for illumination and the exposure period be minimized as much as possible. Air contaminants, mainly acetic acid, formic acid and 2pentyfuran, may accelerate the aging of paper, so air in storage rooms should be kept clean and storage container be ventilated. Mold may also accelerate the aging of paper and discolor it, so disinfection of paper documents must be done before being put in a library.

Abstract:Fourier transform infrared spectroscopy (FTIR) and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) were applied to identify the organic materials used in the guard board mortar of Taihe Dian (Hall of Supreme Harmony) in the Forbidden City. Two guard board mortar samples, collected respectively from the upper layer and the southwest corner of the upper layer of Taihe Dian, were analyzed. FTIR results showed that in the two samples, the inorganic material used was carbonate, and that the organic materials might be lipids or shellac. Py-GC/MS analysis further confirmed that there were vegetable oils in the two samples, perhaps a mixture of raw tung oil and oil from cruciferous plants. Cedrol detected in both samples could be the volatile component of the cedar wood roof boarding of Taihe Dian. In addition, there might also be starch in the sample of upper layer guard board mortar. The present work will contribute to the scientific research and restoration of the traditional guard board mortar used in Taihe Dian.

Abstract:The digital design of cultural heritage relics provides a new method for their conservation, preservation and utilization. Based on digital design theories and methods used for making cultural heritage objects, we reviewed key technologies for the three-dimensional digital design for cultural heritage objects, developed a computer-aided, three-dimensional digital reconstruction method, and proposed the idea of three-dimensional mesh texture mapping using two-dimensional image calibrations. We tested this method by doing three-dimensional digitization of an unearthed bronze bovine object of the late Shang dynasty and constructing a complete design framework, thus verifying our theories and methods.

Abstract:Multi-view three-dimensional reconstruction technology was selected to carry out 3D modeling of a Ming Dynasty bronze Buddha in the Zhangjiajie Museum. This paper describes the process of collecting images from the facade and the hollow bottom of the Buddha, and the specific workflow of Agisoft PhotoScan software used for three-dimensional reconstruction. The error analyses of the 3D coordinate of the control points and the error values, the model imaging and the image results show that the accuracy error of the 3D model of the Buddha is small. Compared with three-dimensional laser scanning technology, the multi-view three-dimensional reconstruction technology has the advantages of low cost, simple and efficient workflow and clear model imaging, which can be further promoted in the use of cultural relics work.