便携式近红外光纤光谱在纺织品文物纤维无损检测中的应用

利用便携式近红外光纤光谱仪,选取了棉、麻、丝、毛、聚酯及16种天然染料作为研究对象,分析了5种染色纤维的近红外光谱的特征吸收峰位。丝的amide A/Ⅱ与amide B/Ⅱ吸收带分别在2 058 nm(4 859 cm~(-1))和2 200 nm(4 545 cm~(-1)),毛的amide A/Ⅱ与amide B/Ⅱ吸收带分别在2 052 nm(4 873 cm~(-1))和2 177 nm(4 593 cm~(-1)),这两个吸收带可作为毛与丝的判据。聚酯的特征吸收在1 660 nm(6 024 cm~(-1))处,来自于聚酯纤维链段中的苯环,可作为聚酯纤维判定的依据。棉和麻的近红外光谱十分接近,无法直接识别,通过Thermo scientific TQ Analyst 8分析软件的判别分析方法(discriminant analysis)建立鉴别模型(标准样品集图谱个数分别为棉70、麻100、丝60、毛67、聚酯70,验证集图谱个数分别为棉20、麻20、丝20、毛20、聚酯20,选取波段为1 600～1 800 nm和2 000～2 100 nm),计算未知材料到每个类别中心的马氏距离,可判断未知样品与棉和麻标准样品的相似性。结果表明:模型性能指数(Performance Index)为95.649,说明模型预测准确,可快速鉴别棉和麻。此外,染料,媒染剂对纤维的特征吸收峰峰位影响较小,在实际应用中不影响判定结果。将该方法应用于四件古代或近代纺织品文物的纤维鉴定,得到了较好的光谱比对结果,并证明了该方法在纺织品文物纤维无损鉴定中的可行性和实用性。     

A non-invasive study of Roman Age mosaic glass tesserae by means of Raman spectroscopy

Ancient mosaic tesserae are a range of materials of very varied and complex nature, including pottery, stone and glass. Raman spectroscopy is a powerful tool for the analysis of all these kinds of materials. In the particular case of glasses, this technique can be used both for a study of surface weathering and for the characterization of bulk structure, but it has not yet been extensively used for the characterization of mosaic glass tesserae. We carried out Raman analyses on a set of Roman and Late Antiquity period mosaic glass samples, which allowed a good characterization of both the glass matrix and the crystalline inclusions. All the samples show the typical Raman signatures of soda-lime-silicate glasses. Several crystalline phases were also identified, being relics of raw materials used during the glass manufacturing process, such as quartz and feldspars, or linked to the glass color/opacification, such as bindheimite and cuprite. The analyses also led to the identification in some blue, turquoise and green tesserae of calcium antimonate, whose Raman signature has only recently been recognized in the scientific literature on mosaic glasses. Some emphasis is given to the analysis of red lead-containing tesserae, colored with Cu⁺ ions or even Cu⁰ (or Au⁰) metal nanoparticles. Samples with peculiar compositions, as well as “modern” (and restoration) samples, could quite easily be distinguished from the ancient ones by their Raman spectra.     

几种罕见的黄铜钱币锈蚀产物的识别与形成原因探析

我国从明中期开始使用黄铜钱币,一直到清末。过去,对古代铸币的科学研究主要集中于合金成分分析和铸造工艺两方面,对锈蚀产物和锈蚀机理的研究主要针对青铜铸币。黄铜的合金元素中较青铜多锌元素,其腐蚀产物与腐蚀行为较青铜有一定的差别,也较青铜更为复杂,然而现有的文献关于此方面的研究匮乏,特别是对于大气保存环境下黄铜钱币的锈蚀产物及锈蚀成因的研究基本空白。本研究通过多种分析手段包括X射线荧光分析仪(XRF)、扫描电镜能谱仪(SEM-EDS)和显微激光拉曼光谱仪(Raman)对国家博物馆馆藏一批传世明清各时期的黄铜钱币合金组成,不同颜色的锈蚀产物等开展科学分析。研究结果表明,嘉靖、隆庆和万历年的黄铜铸币,为Cu+Sn+Pb+Zn四元合金,平均含量Cu 66.4%,Sn 6.8%,Pb 10.4%,Zn 15.6%,并含有微量Fe,不含As。泰昌、天启和崇祯年间及清代各时期的黄铜铸币,主要为Cu+Pb+Zn三元合金,并含有微量Fe、As和Sn。这批黄铜锈蚀产物与常见的青铜锈蚀产物不同,最典型的是钱币表面蓝绿色和白色锈蚀物,经Raman和SEM-EDS分析并结合相关文献初步确认蓝绿色锈蚀物为一种含铜、钠...     

Chemical analysis of 17th century Millefiori glasses excavated in the Monastery of Sta. Clara-a-Velha,Portugal: comparison with Venetian and façon-de-Venise production

A set of ten Millefiori glass fragments dating from the 17th century, originated from archaeological excavations carried out at the Monastery of Sta. Clara-a-Velha (Coimbra, Portugal), were characterized by X-ray electron probe microanalysis (EPMA), Raman microscopy and UV–Visible absorption spectroscopy. All glasses are of soda-lime-silica type. The use of coastal plant ash is suggested by the relatively high content of MgO, K₂O and P₂O₅, as well as by the presence of chlorine. Tin oxide or calcium antimonate were the opacifiers used in the opaque glasses, cobalt in the blue glasses, copper in the turquoise glasses, iron in the yellow and greenish glasses, and iron and copper were found in the opaque red and aventurine glasses. Based on the concentrations of alumina and silica four different sources of silica were identified, allowing the classification of the glasses into the following compositional groups: low alumina (<2 wt%), which includes a sub-group of cristallo samples with SiO₂ > 70 wt%, medium alumina (2–3 wt%), high alumina (3–6 wt%) and very high alumina (>6 wt%). Comparison with genuine Venetian and façon-de-Venise compositions showed that two fragments are of Venetian production, one of Venetian or Spanish production and the remaining are of unknown provenance. In two fragments the glass of the decoration is probably Venetian or Spanish but the glass used in the body is also of unknown provenance.     

Non-destructive analysis of amber artefacts from the prehistoric Cioclovina hoard (Romania)

Amber beads from the Cioclovina hoard (Hunedoara County, Romania), dating from the transitional period between the Late Bronze Age and the Iron Age, were analysed by Fourier transform infrared spectroscopy – variable angle reflectance (FTIR-VAR) and Fourier transform Raman spectroscopy (FT-Raman). The aim was to determine if the raw material came from the shores of the Baltic Sea, on the Amber Route which crosses Central Europe, or if it originated from the area of the main amber occurrences in Romania, in Buz?u County, around the village of Col?i. All applied analyses strongly suggest that a large part of the amber from the Cioclovina deposit has a Romanian origin, and thus no connection with the Amber Route.     

Investigating experimental knapping damage on an antler hammer: a pilot-study using high-resolution imaging and analytical techniques

Organic (bone, antler, wood) knapping tools were undoubtedly a component of early human tool kits since the Lower Palaeolithic. Previous studies have identified pitting and the occasional presence of embedded flint flakes as important features for recognizing archaeological bone and antler percussors. However, no systematic protocol of analysis has been suggested for the study of this rare archaeological material. Here we present qualitative and quantitative results of a preliminary analysis of an experimental knapping hammer, using a novel combination of microscopy (focus variation optical microscope and scanning electron microscope), micro-CT scanning and energy dispersive X-ray spectroscopy. These imaging and analytical techniques are used to characterize use-damage from the manufacture of handaxes. This paper highlights the strengths and weakness of each technique. Use-wear on the working area included attritional bone loss, micro-striations and compaction of the outer layer of the antler matrix from repeated hitting of the beam against the sharp edge of the handaxe during knapping. Embedded flint flakes were also identified in the pits and grooves. This combination of high-resolution imaging techniques is applicable to fragile archaeological specimens, including those encrusted by sediment or encased in matrix.