化学加固材料在石质文物保护中的应用

介绍了石质文物的加固原则和化学加固材料的种类、特点及应用情况,并对研究前景进行了展望     

From stone to metal: New perspectives on the later prehistory of West Africa

Earlier views saw West Africa as culturally stagnant through much of the Holocene until stimulus or intervention from north of the Sahara transformed Iron Age societies. Evidence accumulating over the past 15 years suggests that stone-using societies from 10,000 to 3000 B.P. were far more diverse than previously thought. Against an increasingly detailed record of Holocene climate change, the complexity of local adaptation and change is becoming better understood. Although a strong case currently exists for the introduction of copper and iron to West Africa from the north in the mid-first millennium B.C., the subsequent development of metallurgy was strongly innovative in different parts of the subcontinent. Soon after the advent of metals, a dramatic increase in archaeological evidence for social stratification and hierarchical political structures indicates the emergence of societies markedly more complex than anything currently documented in the Late Stone Age. The best-documented examples come from the Middle Niger region and the Nigerian forest. In these areas, earlier diffusionist models in which complexity originated outside West Africa have yielded to evidence that indigenous processes were instrumental in this transformation. Trade, ideology, climate shifts, and indirect influences from North Africa, including the introduction of the domesticated horse to the Sahelian grasslands, are identified as factors essential to an understanding of these processes.     

The Middle Stone Age of East Africa and the beginnings of regional identity

The history of research into the Middle Stone Age of East Africa and the present state of knowledge of this time period is examined for the region as a whole, with special reference to paleoenvironments. The known MSA sites and occurrences are discussed region by region and attempts are made to fit them into a more precise chronological framework and to assess their cultural affinities. The conclusion is reached that the Middle Stone Age lasted for some 150,000 years but considerably more systematic and in-depth research is needed into this time period, which is now perceived as of great significance since it appears to span the time of the evolution of anatomically Modern humans in the continent, perhaps in East Africa.     

有机-无机复合疏水型二氧化硅涂层制备及性能

为研究制作保护石质文物的加固材料,采用溶胶-凝胶法,以两种有机硅材料(正硅酸乙酯(TEOS)和甲基三乙氧基硅烷(MTES))为共同前驱体,少量正辛胺为催化剂,聚二甲基硅氧烷(PDMS)(方法 1)或硅烷偶联剂KH-570(方法 2)为有机改性剂,制备了有机-无机复合疏水型Si O2涂层。通过红外光谱(FT-IR)、扫描电镜(SEM)和水接触角(WCA)来表征在砖块表面形成的SiO_2膜层化学组成、表面形貌以及疏水性能,然后再通过测试砖块加固前后外观、吸水性能和孔隙率的变化来验证实际加固效果。结果表明,两种方法均可以制备骨架带-CH3基团的SiO_2溶胶。采用方法 1(添加前驱体质量10%的PDMS)或者方法 2(MTES/TEOS质量比为2),加固后的砖块对水接触角均超过140°,毛细吸水率降低到未处理时的1%~2%,并且砖块的色差和光泽度改变较小。通过耐候性能测试表明,方法 2的保护效果相对较好,说明用此种方法合成的疏水性二氧化硅涂层可以作为砖块加固材料。     

地面核磁共振方法在石质文物保护中的应用

石质文物破坏问题不仅在于人为破坏和表面污染,更多来自自然因素对文物的破坏,例如,日晒雨淋、风沙吹蚀、地表水的冲刷、地震、地下水的侵蚀溶蚀。为对第六批全国重点文物保护单位阳华岩摩崖石刻露天石质文物病害进行探查,采用无损探测的地面核磁共振方法和探地雷达方法,直接找水的地面核磁共振方法成功探测出摩崖石刻依附岩体地层含水分布状况。探地雷达方法探测出依附岩山体内岩溶、裂隙的发育状况。两种方法探测结果发现,石刻依附岩体内岩溶、裂隙发育,部分区域岩溶裂隙带已成为地下水汇聚场所或流通通道,对阳华岩摩崖石刻构成了极为严峻的侵蚀威胁。两种方法解释结果互为验证,研究结果为阳华岩摩崖石刻的病害治理和保护提供了宝贵的基础资料。     

Raman spectroscopy and scanning electron microscopy confirm ochre residues on 71 000‐year‐old bifacial tools from Sibudu,South Africa

Micro‐residue analysis of stone tools is generally performed with optical light microscopy and the visual observations are then compared with experimental, replicated pieces. This paper complements such archaeological research by providing physico‐chemical evidence. Raman spectroscopy and scanning electron microscopy have been used to confirm the presence of hematite on red‐stained medial and proximal parts of 71 000‐year‐old Still Bay bifacial tools from Sibudu Cave. Our results confirm the conclusion from optical light microscopy that the tools were hafted with an ochre‐loaded adhesive. However, we point to some instances when hematite residues are incidental or may be inclusions in the rock used to make the stone tools.     

Prehistoric exchange and interaction in southeastern southern africa: Marine shells and ostrich eggshell

The spatiotemporal distribution of seashells and ostrich eggshell in the Later Stone Age of southeastern southern Africa is used to infer several areas of social interaction. The inferred patterns are supported by comparisons with preferences for lithic raw materials and the distribution of bifacial stone arrows. Plusiers zones de l'interaction sociale sont déduites des distributions chronologiques et spatiales de la coquillage et de la coquille de'autruche de l'Age de la Pierre Récent au sud- est de l'Afrique australe. Ces distributions sont soutenues des préférences pour des matières premières lithiques et de la distribution des flèches bifaciales de la pierre. Provincial names and boundaries are as given on May 1, 1994     

Evaluation of Fe isotope values as a provenance tool for chert artefacts from the north-eastern United States

Iron (Fe) isotope compositions of prehistoric stone tools and geological sources were compared to evaluate the robustness of this isotopic fingerprinting technique. Artefacts and source materials were collected from the Hatch site in central Pennsylvania, United States, where both veined chert (Bald Eagle chert) and stone tools coexist within several metres. Yellow artefacts (δ⁵⁶Fe = 0.38 ± 0.1, n = 7) and source materials (δ⁵⁶Fe = 0.42 ± 0.1, n = 8) isotopically matched within error. The source values also overlap yellow chert samples from three other Bald Eagle chert locations in the area. These values are different from six other chert locations in the north-eastern United States. These data suggest that the Fe isotope composition of chert artefacts reflect distinct geological sources. To enhance the mechanical characteristics of the stone tools, the chert experienced heat treatment, which induced a phase shift of the Fe oxide mineral goethite to hematite. This phase shift changes the colour of the chert to red. The red chert artefacts and source material also have overlapping Fe isotope values, but are 0.2‰ higher than the initial yellow chert. Experimental work where cherts were heated with different clays shows that Fe exchange with site soils induces the +0.2 fractionation. These data demonstrate that predictable Fe isotope fractionation occurs during heating, resulting in isotopically distinct artefacts.     

明代石拱桥永昌桥的加固修缮技术研究

为明晰明代石拱桥的结构性能,并提出适宜的加固修缮方法,以典型的明代石拱桥永昌桥为例进行研究。首先对其进行精确测绘,获得其准确可靠的几何信息;然后对其建筑形制、构造工艺及残损状况进行研究,为结构性能分析提供依据;接着利用ANSYS软件建立永昌桥主体结构的有限元模型,进行包括荷载影响分析、重要度分析和裂缝分析的结构性能研究;最后基于现状分析和结构性能研究,通过对比拱背套钢筋混凝土拱加固法和拱背粘贴碳纤维布加固法对石拱桥的结构性能的影响,提出了明代石拱桥永昌桥的加固修缮方法。研究成果可为同类型石拱桥的加固修缮提供参考。     

Provenance Analyses of the Volcanic Rock Grinding Stones from the Greek Colony of Selinunte,Sicily (Italy)—Constraints and Possibilities

The petrography as well as the major and trace element compositions of the Selinunte grinding stones, made of grey vesicular lava, were analysed. By comparison with geochemical data from volcanic rocks in the Mediterranean, we were able to determine that only a minor number of the tools were extracted from the nearest volcanics of Mount Etna and the Hyblean Mountains, while the majority of the grinding stones were most probably imported from the Aeolian Islands, although an origin from the Aegean cannot be excluded entirely. The results are important in order to scrutinize trading connections, especially for the earlier times of settlement during the sixth century bc .