出土饱水云南松的超微构造特征

对云南剑川县出土的木质文物进行了研究,从超微结构层面更深入地解析了饱水古木的降解情况。出土的云南松(Pinus yunnansis)古木在饱水环境中淹埋了4 000多年。降解主要发生在晚材管胞,而且降解在晚材部分并不均匀:一些未降解的完好管胞分布在降解严重的管胞中。透射电镜观察显示:降解从S1/S2和S2/S3的界面开始;对于一些降解较严重的管胞,到腐朽后期细胞次生壁全部发生降解,只留下复合胞间层;细菌侵蚀是云南松饱水古木降解的主要原因。固体核磁共振结果表明:纤维素和半纤维素降解严重,木质素也出现了一定程度的降解。本研究可为其后续的加固保护提供科学的参考依据。     

古代饱水木材脱水定型机理探讨

从木材干缩的一般理论出发,探讨了古代饱水木材脱水变形的主要影响因素。阐述了古代饱水木材与新鲜木材的区别,提出饱水木材发生形变的主要影响因素同现代木材一样,是由于氢键缔合的结合水挥发,从而引起干缩和开裂。要保持脱水后的定型一方面要加固细胞壁外壁,更重要的从细胞壁内壁进行加固。     

考古出土木质文物变定的产生、回复及其永久性固定

本文对降解古木的微观结构进行深入的剖析,阐明其变定的原由,确定木材变定是基于干燥应力而产生。在研究如何控制干燥应力的基础上,研究出考古出土饱水古木变定回复及永久性固定的方法及处理工艺,有效地解决了出土古木保护的瓶颈问题。     

考古木材降解评价的物理指标

为寻找一种能较为科学、方便地反映木材降解程度的指标,共收集不同地方出土的13种木材,8个树种,对这些树种的考古木材与新鲜木材的含水率、干缩性、基本密度、气干密度、综纤维素等指标进行对比分析。实验表明,基本密度和最大含水率(饱水含水率)基本上能够反映古木的降解程度,可以作为反映古木降解程度的物理评价指标。     

云南剑川海门口遗址饱水古木降解的微观构造分析

文中采用扫描电镜(SEM)和透射电镜(TEM)对海门口遗址饱水古木进行降解机理分析。结果表明:古木细胞次生壁收缩严重并与胞间层分离;胞间层保存较完好,呈连续网状。说明古木纤维素和半纤维素降解相对严重,木质素降解相对较轻。古木主要是受细菌降解,通过SEM和TEM均可见明显的细菌腐朽特征。细菌首先侵入细胞腔,再通过S3层侵入细胞壁内部。细胞壁内由于降解而产生的空隙在几十到几百纳米之间。饱水古木也受到了一定程度的真菌降解,但这类真菌主要降解古木内淀粉等物质,对细胞壁物质降解能力差,主要是使古木变色。     

有机硅溶胶-凝胶法饱水木质文物脱水定型加固研究

大多数饱水木质文物被发掘时已经发生了严重的降解,在干燥前若不经过适当的脱水加固处理,将发生严重的变形甚至损毁。在本工作中,基于有机硅氧烷温和的处理条件、良好的渗透性、优异的耐候性和力学性能,我们选用有机硅氧烷通过溶胶-凝胶法对来自东海沉船的饱水古木进行了脱水加固处理,并对有机硅氧烷脱水加固样品进行了扫描电镜(SEM)、X-射线能谱(EDS)、傅里叶变换红外光谱(FTIR)和差热-热重(DSC-TG)表征以评估脱水加固效果和研究脱水加固机理。结果显示有机硅氧烷处理饱水古木能很好地保持古木的外形,收缩率小于6.50%。有机硅氧烷加固样品的抗压强度和弹性模量分别提高了3983%和1939%,热分解温度从364.8℃升高到507.7℃。有机硅氧烷能很好地渗透到饱水古木的中心部分,细胞壁的加固程度和细胞腔的填充程度和处理时间紧密相关。有机硅氧烷加固样品的力学强度随增重率的增加而增强,而增重率则可能与有机硅氧烷的缩合速率有关。     

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。     

珙县“僰人”悬棺维修加固工程结束

省级重点文物保护单位珙县“僰人”悬棺,是我国古代西南少数民族文化的遗存,在民族学上具有很高的价值。由于悬棺置放都是在悬崖陡壁上,长期的日晒雨淋,一部份悬棺木桩腐朽、松动,棺身倾斜,棺木破损。为保护好这一珍贵的历史文物,最近,国家文物局,省文化厅拨出专款,省文物部门派出考古专业人员。对九盏灯、珍珠伞、棺材铺三处悬棺进行维修加固。这次维修加固悬棺,是建国以来的第一次。参加这项工程的全体同志,按照国家文物局维修保护文物的规定,结合实际,较好地解决了工程中有关悬棺木桩的加固,残棺的修复,新材料的应用等复杂的技术问题。对已腐朽松动的木桩,采用将钢筋契入桩孔,再用水泥凝固,使钢筋承     

中国北方干燥地区出土糟朽漆器加固材料及修复方法

为探索一种适合于我国北方干燥地区出土糟朽漆器保护的材料和方法,从而解决这类漆器的保护问题。通过试验比较,以水、乙醇和丙三醇作为中国古代北方干燥地区出土漆器漆皮的回软修复材料;选用乳液型粘合剂与纸、绢、古代木材作为回软漆皮的加固材料;选用聚乙二醇乙醇溶液与Paraloid B72丙酮溶液为渗透加固剂,对三件糟朽漆器加固取得很好的效果。实验表明,本方法为中国北方干燥地区出土糟朽漆器的保护修复,提供了一种科学易行的方法和材料。     

基于古建木构文物修缮的木材抗弯性能实验研究

受自然作用、人为因素及材性退化的影响,已有数百年甚至千年历史的古建筑木结构构件及斗栱节点存在不同程度的损伤,需进行合理修缮加固。而在木结构修缮选材中,抗弯弹性模量是需要考虑的一项重要指标。为了找到更合适的古建筑修缮加固用材,本研究选用五种木材进行横纹径向、弦向和斜向抗弯测试,采用力学试验机以及自制的力传感器通过电阻应变采集仪分别记录了五种木材所受力和位移的关系,然后按荷载与位移的关系分别计算出各自的抗弯弹性模量。通过对五种木材抗弯弹性模量的测量与分析,比较了相同含水率的木材抗弯弹性模量随密度的变化情况。试验表明:同种木材不同受弯方向抗弯弹性模量差异较大;与其他木材相比,落叶松不同受弯方向的平均抗弯弹性模量高于其他木材;木材的抗弯弹性模量有随密度增加而增加的趋势。此试验结果可为今后古建木结构的维修与加固以及构件替换提供参考。     

明清古建筑木结构典型抗震构造问题研究

为保护古建筑,采用分类统计方法,研究了我国明清古建筑木结构的典型抗震构造问题。基于大量工程现场勘查结果,对古建筑木结构的典型抗震构造问题进行了归纳汇总,分析了原因,提出了加固建议;基于典型算例,对古建筑木结构加固方法进行了深入论证。结果表明:我国古建筑木结构的柱子、斗棋、榫卯节点、梁架、屋顶等各部位都容易产生开裂、糟朽、变形、拔榫等抗震构造问题并影响结构的抗震性能,而这些问题的产生原因主要与木结构的构造特征、木材材料性质及施工保养等因素有关;对这些抗震构造问题及时采取合理有效的加固措施,可减轻或避免结构产生的震害。     

Effect on the Structure in Elevation of Wood Deterioration on Small-Pile Foundation: Numerical Analyses

Wooden pile foundations are quite common in Venice historical building. Very short, small-diameter piles are embedded into the soft shallowest soil layer under the groundwater level, but wood degradation is not prevented as anaerobic bacteria can flourish even in anoxic condition. This study couples the behavior of the masonry structure and the foundation as result of pile degradation. The numerical analyses, relative to the ancient piling, consider wood decay and secondary settlement of soil. The effect of deterioration as a function of the pile spacing and the possible presence of a stiff layer under pile tips are also investigated. The geotechnical results are then used as input for the structural model. The behavior of the masonry as result of different states of wood conservation along the wall is studied numerically.     

古建筑木构件的防火处理与性能研究

古建筑具有重要的文化价值和经济价值,是重要的不可再生文化遗产。中国的古建筑以木为主要结构,而木结构的耐火等级低,这就造成了中国古建筑面临了一个极大的隐患——火灾,因此对古建筑木构件的防火处理与性能的研究迫在眉睫。为此,试验选取3种不同的木材和5种不同的阻燃剂作为研究对象,首先对涂覆不同阻燃剂的木材进行表观特征测量,然后分别采用热重分析法和扫描电子显微镜测试技术进行表征测试,最后分析阻燃木材的各种力学性能测试。研究结果表明:喷涂阻燃剂的木材其性能效果均优于未喷涂的木材。特别针对未涂油漆的原木构件,可以采用有机磷杂环阻燃剂或磷—氮类阻燃剂;普通油漆的木构件则适用于磷—氮类阻燃剂,而处理桐油木构件应用磷—氮类阻燃剂或阻燃油。     

新型氟硅丙烯酸树脂镀膜技术在榆木类木构古建筑保护领域的应用研究

本工作以江西省赣州市大余县左拔镇云山村晚清时期的榆木木构民居建筑为保护研究对象,从新型氟硅丙烯酸树脂材料的分子设计、镀膜剂配方与涂布工艺的优化等方面入手,对该地区榆木类古建筑的镀膜保护技术进行了研究。研究结果表明,由甲基丙烯酸十二氟庚酯、γ-甲基丙烯酰氧基丙基三甲氧基硅烷与丙烯酸酯等单体的多元共聚制备得到的氟硅丙烯酸树脂镀膜剂,具有良好的耐化学腐蚀性、耐候性、疏水疏油性、抑菌、超薄、高透光性(无反光)和阻燃等综合特性。该镀膜剂可采用传统涂布工艺,涂布与成膜过程无有毒有害物质排放,可实现对木质材料纤维微结构表面的有效包覆,在不改变榆木类木构古建筑外观的情况下,实现对榆木类木构古建筑的有效保护。     

建水指林寺大殿木构件材种鉴定及配置研究

木材树种的鉴定是古木结构建筑维修和保护的基础性工作。为配合建水县指林寺大殿修缮保护的需要,为修缮树种选用提供依据,了解木文化的特点。本研究对建水指林寺大殿古建筑主要木构件进行了树种鉴定及对材种配置调查分析。采用切片、显微镜拍照、宏观和微观特征分析等方法,对700个试样进行了树种鉴定。结果表明建水指林寺大殿的木构件共有4个树种,分别是硬木松(Pinus sp.)、白青冈(Cyclobalanopsis sp.)、格木(Erythrophleum sp.)和荷木(Schima sp.)。通过材种配置分析可得指林寺大殿木构件在选材方面达到很高水平,不仅反应了建造年代,而且体现修缮的特性。     

Water,Wind, Wood,and Trees: Interactions,Spatial Variations,Temporal Dynamics,and their Potential Role in River Rehabilitation

Recent Australian research has quantified the role of large wood (wood of any origin and length with a diameter greater than 0.1 m) in dissipating stream energy, forming pool habitats by local bed scour, protecting river banks from erosion, and damming rivers with long rafts causing avulsions. Large wood in Australian streams is sourced by a range of processes from the nearby riparian zone which has usually been degraded by post‐European settlement vegetation clearing. Large wood loadings within the bankfull channel are dependent not only on the type and quality of the riparian plant community but also on bankfull specific stream power, channel width, and the processes of large wood delivery to the stream. While bank erosion and floodplain stripping by catastrophic floods are obvious and important delivery mechanisms, treefall and trunk and branch breakage by strong winds during tropical cyclones and severe storms are also significant in the tropics. Furthermore, wood decay and downstream transport produce temporally dynamic large wood distributions. The longevity of natural large wood structures in rivers, such as rafts, debris dams, and log steps, requires determination. River rehabilitation programs need to not only include the reintroduction of large wood, but also carefully plan the spatial distribution of that wood, the most appropriate type and range of large wood structures, and, most importantly, the revegetation of the riparian zone to ensure a natural long‐term source of large wood. Exotic species management is an essential part of river rehabilitation.     

明代两件加彩木雕坐像的保护处理——以馆藏明代加彩木雕坐像的保护处理为例

针对深圳博物馆收藏两件明代加彩木雕坐像存在的虫蛀、糟朽、彩绘脱落、开裂、残损等病害,急需进行保护处理的情况。本工作在前期调研和分析检测的基础上,即分别采集了木雕坐像的胎木、加彩层、污染物等样品,利用红外光谱、拉曼、扫描电镜等分析方法对其材质组成、制作工艺及病害进行了综合分析基础上,建立了坐像保护处理工艺步骤:原始档案建立、表面清理、菌虫防治处理、木质朽蚀部位和彩绘层渗透加固、破损及残缺部位修复补全、建立保护修复档案等。选择Primal SF-016作为两件木雕坐像的渗透加固材料,选择无水乙醇作为溶剂,采用较低浓度多次渗透的方法,保证了最佳的加固和防腐防虫效果;修补材料选择聚醋酸乙烯乳液和锯木屑调和补配。处理后的木雕文物器形完整,形态稳定,色泽协调,达到了理想的保护效果。这是对传世彩绘木质文物保护技术的有益探索,对日后同类文物的加固处理有借鉴意义。     

Reasoned use of chemical parameters for the diagnostic evaluation of the state of preservation of waterlogged archaeological wood

Waterlogged archaeological wood undergoes decay processes that depend on both the burial conditions and the constituting species, and which cause the depletion of the structural components of wood cells. To quantitatively assess the state of preservation of the decayed material, specific parameters are usually measured by means of both chemical and physical analyses. In this paper an innovative approach in the use of the data obtained from these kinds of measurements is developed. A series of 132 archaeological wood samples of different wood species, burial times and states of preservation, and coming from different sites in Italy, was analysed. Their residual chemical composition, maximum water content and basic density were measured, and a reasoned use of these parameters was carried out through their elaboration, with the aim of both evaluating eventual incongruence or anomalies in the raw physical and chemical data (which has never been accomplished so far) and directly comparing in a reliable way the analytical results obtained from archaeological samples with very different states of preservation. This approach allowed defining the effective values of chemical parameters related to wood decay according to a same reference basis of calculation among the various data. By this way, it was possible to state that lignin can be also attacked by the agents causing biotic decay, and that in hardwoods its decay is more related to the burial conditions than to the wood species. Instead, the mechanism of polysaccharide depletion is diversified: conifers showed a uniform behaviour whereas hardwoods were more species-dependent. Moreover, in addition to the chemical composition, also anatomical factors influence the carbohydrate rate of decay in waterlogged wood.     

Wood deterioration in Chacoan great houses of the southwestern United States

Abstract

‘Great houses’ built by the Ancestral Puebloans (Anasazi) (900–1200AD) still contain thousands of pieces of wood used as beams, secondary roof supports and lintels. The wood is an integral part of the surviving Chacoan architecture and has served as a valuable resource for determining the exact age of the structures and for obtaining information about raw material production, procurement and harvesting methods. An assessment of wood deterioration at the great houses in Aztec Ruins National Monument and Pueblo Bonito, Pueblo del Arroyo and Chetro Ked located in Chaco Culture National Historic Park in New Mexico have revealed that both microbial and non-biological deterioration was taking place. The major type of decay found throughout the structures was caused by soft-rot fungi. Cavity formation in secondary walls of conifer woods and an erosion of cell walls in aspen woods was prevalent. A brown-rot type of wood degradation was also found, primarily associated with areas of subterranean termite damage. Another form of deterioration present in some of the woods was a chemical de fibration of wood. This corrosive attack, caused by high concentrations of salts, destroyed the middle lamella between cells, resulting in a stringy mass of loosely attached fibres. Reburial of great house structures as an effective conservation strategy will require an environment that is not conducive to decay, since active wood-destroying fungi are present in the prehistoric woods. If moisture and other conditions suitable for decay exist, the wood will be destroyed and this important historical resource lost.     

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