出土、出水饱水木质文物冷冻干燥研究进展

冷冻干燥是稳定出土、出水饱水木质文物的主要方法之一。该方法基于水由固态直接成为气态的升华过程不产生表面张力的原理,可避免饱水木材脱水时受到干燥应力的破坏。数十年来,经过实验实践和不断完善,冷冻干燥在出土、出水降解木材的稳定中取得了很好的效果,在大型、厚重木质文物的保护方面得到成功应用。本研究基于在出土、出水含盐饱水木质文物保护方面的多年实践,对国内外在脱盐、抗菌、热浸、预冻和升华干燥工艺等方面的进展进行了回顾,并提出了解决一些现有问题的技术设想。     

Soluble Salts Amplify the Effect of Small Heterogeneities in the Structure of Porous Building Materials During Drying

Salt crystallization is a major cause of degradation in old buildings. One of the issues that stills need clarification is regarding the influence of the salts on the capillary absorption and subsequent drying of porous building materials. This article presents an experimental study that included capillary absorption and evaporative drying tests on two types of material (lime mortar and ceramic brick) using pure water or saturated solutions of six salts (sodium chloride, sodium sulfate, sodium nitrate, sodium carbonate, potassium nitrate, or potassium carbonate). The results of capillary absorption agree only roughly with the linear relationship, predicted by theory, between sorptivity and the square root of the ratio between viscosity η and surface tension σ of the solution (σ/η)^1/2. This poor agreement is probably due to material heterogeneity. The drying dynamics was regular and showed little dispersion between specimens, but only for the uncontaminated materials. Indeed, the drying dynamics of the salt contaminated materials was often irregular or diverged among similar specimens, and the same happened with their salt decay patterns. The main conclusion is that soluble salts can amplify the effects on drying of the small structural heterogeneities that porous building materials normally depict.     

John Locke on Native Right,Colonial Possession,and the Concept of Vacuum domicilium

The early paragraphs of John Locke’s Second Treatise of Government (1690) describe a poetic idyll of property acquisition widely supposed by contemporary theorists and historians to have cast the template for imperial possessions in the New World. This reading ignores the surprises lurking in Locke’s later chapters on conquest, usurpation, and tyranny, where he affirms that native rights to lands and possessions survive to succeeding generations. Locke warned his readers that this “will seem a strange doctrine, it being quite contrary to the practice of the world.” His doctrine of native right is equally strange to recent scholars who see in Lockean theory the ideological prototype for England’s colonial expropriation in the “vacant lands” of North America. This interpretation, dignified by the elusive principle of vacuum domicilium, is considerably weakened when Locke’s arguments are placed in the historical context of the sixteenth and early seventeenth-century English colonial experience. Locke’s Second Treatise, with its literary flourish of a vast and idyllic state of nature, was written in the full appreciation of Amerindian agriculture, its established populations, the acknowledgement of native property rights, and the policy and practice of purchasing land from the native inhabitants.     

纸张DEZ气相脱酸应用研究

通过 DEZ 对酸性纸进行脱酸应用的研究,考核了真空处理器的性能,筛选了处理工艺条件(真空度、温度、处理时间、DEZ 投放量及其关系等).确定了最佳的参数:真空度不低于13.33 Pa;温度控制在60C 左右;DEZ 投入量为需脱酸纸张重量的2％即可得到脱酸的效果。2m~3真空处理器的设计合理.适应 DEZ 气相脱酸的要求,容量大,一次能处理5000册杂志,除了能完成脱酸外,还能消毒、杀虫,具有多功能的特点。DEZ 对酸性纸脱酸有较宽的适应性,能对各种质地、成册的图书进行脱酸中和,pH 值均在中性偏碱范围,证实了 DEZ 气相脱酸的优越性能,为保护文化遗产,提供了一种新的手段和方法。     

Mussels and mongongo nuts: logistical visits to the Cape west coast,South Africa

Very large late Holocene shell middens (‘megamiddens’, some over 10 000 m³ in extent) along a 20 km section of the west coast of South Africa provide a particular interpretative challenge in determining whether they result from residential visits or from logistical processing of shellfish for transport and consumption elsewhere. The latter interpretation is preferred here and is consistent with stable carbon isotopic readings on coastal human burials and site contents that illustrate that groups visited specific localities, collected and dried black mussels and then transported and consumed the dried product inland. The sizes and contents of these large middens contrasts sharply with those of unquestionably residential residues from earlier and later time periods. This approach is supported with reference to the ethnographically described processing and consumption of mongongo nuts by 20th century San of the Kalahari.     

古建筑木结构的保护问题

我国古建筑以木结构体系为主,主要承重材料是木材。木材是生物体,由有机物组成,容易发生腐朽、虫蛀、火灾和力学性能衰减等劣化,其中腐朽和虫蛀等生物危害的发生最为普遍。本文重点介绍了古建筑修缮和保护中,木材的保存、干燥、木材防腐处理的通用药剂和使用方法,针对古建筑保护中存在的树种选择困难、木材防腐处理质量和木材含水率过高等问题,提出建议,为古建筑木结构的保护和维修提供最新的信息。     

饱水文物传统脱水方法与超临界流体干燥技术的应用

饱水文物的脱水加固是文物保护中的一个重要组成部分,为了克服干燥应力引起的文物结构的收缩和塌陷,传统脱水方法中常采用加填充剂浸渍等方法,从而使文物处理周期延长。超临界流体干燥技术利用气体在临界温度以上无论加多大压力都不能液化的特性,控制饱水文物内部的液体在临界点之上,使气/液界面消失,在无液相表面张力情况下进行的干燥过程。本工作在回顾传统饱水文物脱水加固的常用方法和存在问题的基础上,利用液体表面张力与温度的关系,从理论上解释超临界流体干燥技术用于干燥饱水文物具有能消除干燥应力的特点,介绍了国外学者利用该技术实际处理饱水文物时采用的实验装置、操作条件和干燥效果。与传统脱水方法对照,超临界流体干燥技术还具有能缩短文物处理周期、干燥过程中能同时杀菌等优点。     

严重朽蚀饱水竹简的真空冷冻干燥研究

１９９４年我馆陆续抢救了一批流落散失在境外具历史价值的战国竹简,这批竹简的相对含水率达８１．５％,严重朽蚀,有些已散成竹丝状。针对这一特点,本文运用了醇醚法中的部分工艺和真空冷冻干燥原理相结合的脱水方法,采用的ＧＸ－ＰＶＢ－ｔ－ＢｕＯＨ混合预处理溶液分子量小,粘度低,溶液呈中性,可任意配制浓度,用该溶液处理后的严重朽蚀饱水竹简,真空冷冻干燥后,脱水定形效果良好。该方法无需高真空设备,具有处理周期短,处理后竹简色泽自然等特点。除此之外,本文还研究了这批竹材的归属,变色原因,扭曲整形,竹筒上朱砂印记的保存等方面问题。     

受控冷冻灭虫法的风险控制

受控冷冻灭虫的关键在受控,受控指标包括冷冻温度、降温速度与冷冻时间,受控的目的是要达到彻底灭虫。冷冻温度与降温速度直接影响到被冷冻物品的形体安全,保障物品安全为前提的受控冷冻灭虫需要管控风险。基于文献分析、相关问题的调研与理论研究发现,温度不够低、降温速度不够快以及灭虫时间过短都会造成灭虫不彻底的风险。极端低温与快速降温带来物品的损伤与被冷冻物品的材料性质相关,将在极端低温与热冲击力下必然会损坏的材料排除在冷冻灭虫的许可范围之外,科学地选择冷冻温度与加强冷冻灭虫过程管控,可使受控冷冻灭虫化险为夷,即以保证藏品安全为前提的彻底灭虫。     

实验室模拟硅酸盐质文物除盐控盐的可视化研究

针对目前广泛使用的材料吸附除盐和加湿喷雾控盐等方法对含盐硅酸盐质文物可能造成的损伤,采用扫描电子显微镜、电阻仪和高分辨摄影仪等实时在线记录具有显色性质硫酸铜溶液在吸附除盐和水雾控盐加湿干燥过程中文物内部盐带分布的变化。研究结果表明：吸附材料除盐法和表面喷雾控盐法均会加速样品内部盐离子的扩散迁移,在样品中形成双层或多层盐结晶带;所形成的盐结晶带与样品结构特性、盐溶液在样品中的运移和蒸发速率、加湿-干燥频率等因素有关,其中溶液毛细上升高度和样品透气性越好,以及环境温度和盐溶液浓度越高,加湿-干燥频率越快,样品内部的盐带分布变化越明显。材料吸附除盐和水雾控盐等方法加速了盐溶液在样品内部的扩散,促进多层盐带的形成。这些结果对于目前文物保护所采取的除盐控盐技术手段提出了新的挑战。