故宫长春宫木构件材质劣化研究

为了探讨故宫长春宫承重木构件的老化及其机理,从长春宫主殿明间(C1)及主殿外南侧立柱(C2)外观开裂、变色严重部位分别取样,在木构件材种鉴定的基础上,分析了木构件的化学组分;并通过X射线衍射分析(XRD)、热重分析(DTG)以及红外光谱分析(IR),测定了木构件的相对结晶度以及组分中化学基团的变化。研究结果表明,受试木构件中的纤维素、木质素以及半纤维素含量均不同程度下降;由于长期暴露在自然环境中,C2木构件降解程度比较严重,其纤维素含量下降较C1木构件更快;DTG分析结果表明,在纤维素快速下降的同时,C2木构件半纤维素含量也发生了明显的降解,进而导致C2中的相对结晶度远远低于C1木构件;红外光谱对木构件化学基团变化分析结果表明,与同种现代材相比,C1、C2木构件在波数分别为1 732,1 635,1 510和1 460 cm~(-1)处吸收峰减弱和消失,这表明受试木构件化学组分的降解非常明显,尤以C2木构件木材化学组分降解更加严重。另外,C2木构件在波数1 510 cm~(-1)处的吸收峰完全消失,而该处应为芳香族的木质素苯环骨架振动特征吸收峰。这一现象表明光降解是C2木构件老化的主要原因之一。     

Tree-rings and archaeology: some problems explained

Some uncertainty amongst archaeologists about dendrochronology has prompted an explanation of some of the points which cause most concern. These include the probability of obtaining a date for a wood sample and the reliability and accuracy of that date. Uses of tree-ring analysis, other than for dating, are also mentioned.     

甘肃出土糟朽木器的形态与结构分析

甘肃出土木器依据形态与结构划分,属于典型的糟朽木器类型,材质外观特征与特性明显。制作材质鉴定表明,基本类型有①松科云杉;②松科冷杉;③柏科圆柏。通过对糟朽木器形态类型、结构属性、影响因素及发生改变原因剖析,指出了糟朽木器材质在经历了第一阶段的转折性根本改变后（含水率远低于纤维饱和点）,即将面临第二阶段的转折性根本变化（含水率略高或接近于平衡含水率）,而这一阶段的改变结果对器物将是毁灭性的;为了避免出土器物在短期内形态发生剧变,运用生物切片、扫描电镜分析技术对木质纤维显微结构进行了观察和研究,研究结果与结构病害腐变结果相吻合。选取与糟朽器物同期考古出土的糟朽棺板木作为分析对象,分别对其化学成分、容积重、含水率以及力学性能进行了实验测试,测得糟朽木器降解损失超过50%,含水率约为10.5%,力学强度指标与正常材质相比,均有明显的下降,且相对差异较大,最大约为正常木材强度的60%。对比分析结果,得出了结论：①糟朽木器的形态与结构状况与实验生物切片分析、电镜显微结构观察和研究结果相吻合,同时材质成分、容积重与力学性能测定结果为上述分析结果提供了有力的数据支撑;②致使糟朽木器形态和结构发生改变的主要因素是胎木含水率,其值是非恒定的并随外部环境而改变,因此含水率可用于反映糟朽木器的材质特性;③纤维饱和点与平衡含水率是影响、衡量和评估糟朽木器形态与结构的两个重要的物理参数;④鉴于糟朽木器的材质特性,后期保存应尽量避免与水分的直接接触,需要严格控制其胎木的含水率,且维持恒定、稳定的保存环境,这点对后期糟朽木器的保存是非常重要的     

New trials in the consolidation of waterlogged archaeological wood with different acetone-carried products

Some acetone-carried consolidants for waterlogged archaeological wood were tested in order to evaluate treatments able to save time and energy. In details, colophony (rosin), two esterified colophonies (Rosin 100^® and Rosin 459^®), a mixture of colophony with PEG 3400 and a vinyl acetate - vinyl versate copolymer (Vinavil 8020S^®) were tested. The treatments were carried out at temperatures of 20 and 35 °C on waterlogged maritime pine, elm, oak and beech. The materials came from the archaeological site of the ancient ships of Pisa (Tuscany, Italy) and were dated back to VII cent. BC – II cent. AD. To evaluate the processes, equilibrium moisture content and dimensional stability of treated wood samples at different relative humidity, and retention of impregnating products were measured; moreover macroscopic and microscopic examination were also run to respectively assess the shape and appearance of treated wood and the way of deposition of consolidants. The results highlighted that natural and modified colophony treatments gave the most satisfactory results both in the maintenance of shape and dimensions of samples and in the stabilization with respect to RH variations. Moreover, the equilibrium moisture contents of samples treated with R100 and R459 were much reduced in comparison to the other consolidants and to untreated archaeological wood. This fact was related to the high retention values of those products that occluded most of the porosity including the microporosity of cell walls. Therefore, in terms of higroscopicity treated wood was more similar to impregnating substances rather than to decayed wood. This fact was considered helpful in contrasting the moisture-related negative effects in cases of eventual faults in the climate control during e.g. exhibition and in protecting treated wood from the risks of new fungal attacks.     

On the provenience of wood used in the manufacture of snuff trays from San Pedro de Atacama (Northern Chile)

The consumption of hallucinogenic substances is a long-standing tradition in the Americas. San Pedro de Atacama (SPA) in Northern Chile is the archaeological zone with the highest incidence of snuffing implements in the world. Snuff trays from SPA have been studied under a variety of prisms but their provenience, in particular that of the wood used in their manufacture, has not yet been addressed. The delicate nature of trays and their excellent state of preservation call for the use of non-invasive analytical methods. Wood density was used to demarcate a possible range of species and hence as a broad provenience marker, and its value determined for 169 trays from the museum at San Pedro de Atacama. The results showed that although some of the SPA snuff trays studied may have been manufactured with local wood, most of them used exogenous wood as raw material. At this point, it is not possible to ascertain the precise origin of such wood, but Bolivia and NWA appear as likely candidates. Three distinct styles have been defined for SPA trays: Tiwanaku, San Pedro, and Circumpuneño (encompassing the area around the Puna de Atacama and including SPA). The effect of style on density points to different sources of wood in Tiwanaku style trays and trays in San Pedro and Circumpuneño styles. As expected from geographically and temporally dynamic patterns of interaction of SPA with neighboring regions, diachronic differences in wood density distributions were found. Tray manufacturing technique was not dependent on wood density, suggesting that the skill of artisans and the quality of their tools allowed them to use any type of wood for their art work, independent of its complexity.     

关于木构建筑遗迹考古发掘的几个问题

明了木构建筑遗存形式与埋藏条件、发掘过程的关系,以及木桩、木柱、柱洞、柱坑的概念,才能对木构建筑遗迹作出准确的判断,辨证、灵活地运用层位学原理对木构建筑遗迹进行考古发掘。     

Trees and shrubs: the use of wood in prehispanic Teotihuacan

Charcoal recovered from different archaeological excavations carried out in the Teotihuacan Valley, México was used to evaluate whether significant changes in the use of wood took place through time (approx. 400 B.C.–A.D. 1500). Sixteen taxa of trees and shrubs characteristic of the Basin of Mexico were identified (including Pinus, Quercus, Arbutus, Cupressaceae, Alnus, Prunus, Taxodium, Salix, Baccharis and Buddleia, among others). Variations in the proportions of taxa are interpreted as a reflection of the intensity of use rather than an indicator of deforestation. The analysis of the data shows a pattern of continuity in the utilization of taxa throughout the occupation. This includes the use of different vegetative parts (trunk and branches), genera and species with different life forms (trees, shrubs, herbaceous plants) and primary (Pinus and Quercus) as well as secondary taxa (Prunus and Arbutus). We propose that the inhabitants of the Teotihuacan Valley implemented practices to manage vegetation in order to assure resource availability in the region.     

微生物技术在文物保护中的应用研究述略

近年来,微生物技术作为一种新方法开始在文物保护中应用,并且受到越来越多国内外专家学者的重视。文物保护中应用的微生物技术可视为一种运用生物体来生成材料的科学与技术。构建“生物技术-文物保护”技术体系,运用微生物技术方法保护文物,有较好的应用前景。本文通过查阅国内外文献,简要概括了国内外微生物技术在各类材质文物保护中的研究现状。     

Identifying the woody resources of Diepkloof Rock Shelter (South Africa) using scanning electron microscopy of the MSA wood charcoal assemblages

This article presents the results of the anatomical identification of wood charcoal from pre-Still Bay, Still Bay and Howiesons Poort assemblages at Diepkloof Rock Shelter (South Africa) using scanning electron microscopy. In the earliest phases, with pre-Still Bay stone tools, the charcoal shows a predominance of Afromontane forest taxa, some riverine woodland species, mesic thicket and proteoid fynbos vegetation. With a change in lithic technology in Still Bay contexts, the balance of Afromontane and thicket taxa shifts towards favouring the latter. A more diverse array of proteoid fynbos species emerges, and there is evidence for the use of plants from the local wetlands of the Verlorenvlei. In Howiesons Poort contexts, typified by a different lithic technology, the charcoal shows some Afromontane forest persisting, but the overwhelming change is towards greater species diversity, with the woody taxa being increasingly representative of thicket and shrubland. Some of the fynbos and thicket species are typical of vegetational communities which inhabit well-drained soils, rocky or dry locations at the present day. More wetland plants from the Verlorenvlei were selected for use.     

The use of wood in funerary pyres: random gathering or special selection of species? Case study of three necropolises from Poland

In this study, the analysis of charcoal remains from three prehistoric necropolises is presented. This botanical material formed part of funerary pyres and thus represents purposely gathered wood used for cremation ceremonies. Therefore, its anthracological analysis may indicate a special selection of wood, which may be a source of palaeoethnographic information about past rituals. However, a question remains as to whether or not the charcoal assemblages that originated from graves may also provide some palaeoecological information. In order to test both hypotheses, analysis of three Polish necropolises dating to the Bronze and the Iron Age were performed. In all charcoal assemblages, a taxonomic diversity among charcoals was detected, which may suggest that the wood was collected based on availability. This may also be inferred after observing that the presence of the most ubiquitous and frequently found taxa may be strongly correlated with present-day vegetation growing in the vicinity of the necropolises.