Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road

A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhöhle). Its original painted surface is soot blackened and largely illegible. Grünwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified.     

分光计调节的一种简易方法

分光计的调节是光学实验中的一大难题.本文对分光计调节中出现的一些现象进行分析,并提出了简便而又快速的调节方法.     

苯甲酸分子的简正振动与拉曼光谱

利用量子化学软件计算得出了苯甲酸分子的平衡构形,基于这个构形,理论上计算出了苯甲酸分子的简正振动光谱,并与实验测得的结果进行了比较,最后对其简正振动模式进行了全面归属.     

高纯盐酸中铁含量分析法方法比对——ICP光谱法与分光光度法

应用分光光度法和ICP光谱法两种仪器分析方法,对高纯盐酸中的铁含量进行了比对分析,并对可能的误差来源作了阐述。阐述了ICP光谱法比较于分光光度法较好的准确性和精确度。     

基于微波分光仪的雷达原理模拟实验设计

介绍了利用实验室现有微波分光仪模拟雷达基本原理的实验设计方法,具体包括微波定向传输,目标对微波的反射和散射,隐身技术。通过本实验,使学生学习和了解有关雷达的基本原理,激发学生探索科学的热情和好奇心,培养学生对现代科学技术的研究兴趣。     

The Russian avant-garde painting palette: Documentary and physicochemical codification of organic colorants

In the present article an attempt is made to elucidate the organic colorants commonly encountered in the Russian avant-garde painting palette by a combined art historical, documentary and physicochemical investigation, and to examine the influence of environmental factors on the chromatic profile originally sought by the artist. The overall approach based on written sources is confirmed by measurements on relevant paintings. The documentary research deals with the influences of Orthodox iconography, folkloric art, and occidental modernist tendencies on the Russian avant-garde palette, and studies the effects of contradictory historical processes in the chromatic profile of individual paintings. In the experimental section a series of colorants are investigated concerning the effects of accelerated ageing on experimental painting tables, prepared as watercolor and gouache layers on paper ground. The resulting samples are subjected to colorimetric and spectroscopic measurements, and analogous analytical procedures are applied on samples taken from selected paintings. A systematic comparative study of all data permits evaluation of the materials used in terms of their stability towards extrinsic factors, and proposal of degradation routes in order to assist museum curators and conservators in every concrete case related to the broad spectrum of pigments examined.     

Study of the stability of a series of synthetic colorants applied with styrene-acrylic copolymer, widely used in contemporary paintings, concerning the effects of accelerated ageing

This study examines the materials of a contemporary pictorial artwork, belonging to the Macedonian Museum of Contemporary Art in Thessaloniki (Greece), and needing conservation. The combined use of micro-FTIR and micro-Raman spectroscopy allowed the identification of almost all painting materials. Moreover, the stability of a series of synthetic pigments towards accelerated ageing is investigated in applications using the contemporary binding medium styrene-acrylic copolymer. The pigments in question are: Hansa yellow PY3 and PY74, quinacridone PV19 and PR122, naphthol AS PR112, phthalocyanine green PG7 and blue PB15, dioxazine PV37, van Dyck brown PBk11, ivory black PBk9, and titanium dioxide PW6. The organic pigments were applied alone or mixed with titanium dioxide, in rutile form or as a mixture of rutile/anatase. The experimental swatches were subjected to ageing tests, and subsequently studied as to colour changes by means of colorimetric measurements, and as to the molecular structure differentiations by infrared spectroscopy in reflectance mode. The ageing tests included exposure to high temperature and humidity (90 °C, 60% RH) and to ultraviolet radiation (350 nm, 30 °C and 50% RH, with a substantial temperature increase at 90 °C for 3 days). The greater colour difference is caused by high temperature and humidity, whereas paint layers containing TiO₂, and especially the mixture of the forms rutile/anatase, prove very susceptible to ultraviolet radiation, demonstrating a significant colour difference and extended molecular changes.     

Chinese archaeological artefacts: Microstructure and corrosion behaviour of high-leaded bronzes

Metallographic features of ancient bronze artefacts often hide peculiar micro-chemical processes and corrosion behaviours, which are worth to be studied as they can provide conservators and archaeologists with valuable tools and information. It is widely documented that Chinese bronzes were cast and the way to adjust their properties was to change the alloy composition. In particular, addition of lead, which is insoluble in the bronze matrix, results in the formation of inclusions or globules, which undergo oxidation processes leading to their conversion into corrosion products. The mechanisms through which this occurs were still poorly investigated. The present work was conducted to further study the corrosion behaviour of high-leaded bronze, especially focusing on the behaviour of lead globules. To this aim, a collection of Chinese archaeological bronzes, showing intermediate steps of degradation, were selected and investigated. The use of combined microscopy-based, molecular and elemental, analytical techniques allowed the characterization as well as the precise location of corrosion products, thus enabling us to propose a degradation pathway basing on thermodynamic data provided by Pourbaix diagram. The achieved results will be useful for researchers involved in these kinds of studies to better interpret data obtained.     

分光计与读数显微镜的保养和维护

分光计与读数显微镜是常用的光学仪器,使用频率高。为了保正光学实验仪器的正常使用,同时延长仪器的寿命,总结了两种光学仪器保养与维护的有效方法。     

北京谱仪主漂移室的径迹拟合

本文作出了北京谱仪主漂移室的径迹拟合程序包,阐述了该程序包的原理,并运用e~+e~-→i/Ψ→μ~+μ~-蒙得卡罗事例进行检验,动量分辨符合要求.该程序包目前已用于北京谱仪J/Ψ物理的研究之中.