Chemical Analysis of Historic Art and Painting Conservation Materials (19th and 20th Centuries) from the National Museum in Krakow by Gas Chromatography–Mass Spectrometry and Fourier Transform Infrared Spectroscopy

Chemical composition of varnishes Vernis a Tableaux Vibert by Lefranc & Cie, Schutzfirnis für Oelgemalde Schmincke's Retuschier-Firnis by Schmincke & Co. Düsseldorf, Tempera-Firnis by Schmincke & Co. Düsseldorf, Bernstein-Gemaldefirniss für Ludwig'sche Petroleumfarben by Dr. Schoenfeld Düsseldorf, and Vernis Martin Pour Laquer by Lefranc & Cie Paris; oil medium Copal en pâte by Duroziez; essential oils Oleum Cupressi by Polak & Schwarz and Oleum Calami by Polak & Schwarz; fixative for charcoal, crayons, and pastels Nr 840/4 by Iskra & Karmański; and restoring medium for paintings Prof. Dr. Büttner's Phobus by Schmincke Düsseldorf were analyzed with gas chromatography–mass spectrometry. The analyses were conducted to obtain information about the exact composition of these products, which are stored at the National Museum in Krakow and were used by conservators. The results of research facilitate understanding of processes used in paintings and planning methods for their conservation.     

HIAF-BRing的双向涂抹注入模拟

BRing是HIAF工程的主加速器,其设计流强为每个脉冲内的粒子数1×1011个（238U34+）,为了达到此设计流强,注入增益应达到88倍以上。BRing采用了双向涂抹注入方案,其满足BRing的注入增益要求,同时具有注入时间短和累计束分布较均匀而减小了空间电荷效应的特点。双向涂抹注入方案利用水平和垂直两组凸轨磁铁以及倾斜的静电偏转板,在水平相空间和垂直相空间内同时进行涂抹。为了检验双向涂抹注入方案能否达到BRing的设计要求,利用ORBIT程序对双向涂抹注入过程进行了模拟,模拟结果显示,在单次双向涂抹注入113圈的情况下,注入效率为97.7%,注入增益达到110.3倍,满足了BRing流强要求。累积束的分布相对均匀,空间电荷效应引起的工作点漂移约为-0.02,粒子因共振损失风险很小。针对注入束流偏角、切割板角度、工作点偏差和Bump延时等不同注入参数进行了误差分析,结果显示BRing的双向涂抹注入效率对注入参数偏差的容忍度较高。BRing is the main accelerator of High Intensity heavy Ion Accelerator Facility(HIAF) and its design current is 1×1011 particles per pulse (238U34+). To accumulate beams up to the design current, the injection gain has to reach 88. Two planes painting injection scheme is proposed for BRing. This scheme uses a tilted electrostatic septum and 8 bump magnets to paint beams into horizontal and vertical phase space simultaneously. It can inject enough beams into the ring in a short time and paint beams uniformly. The injection process is simulated using ORBIT code and 113 turns is injected into BRing with an injection efficiency of 97.7% which meets the requirement for beam current of BRing. The accumulated beams are distributed uniformly in transverse and hence have a little tune shift of -0.02 which reduces the risk of beam loss due to the resonance. Errors of injection parameters are analysed and the result shows two planes painting injection scheme has a high tolerance for errors of injection parameters.     

基于色差分析的中国淡彩绘画保护性照明光源

为得到博物馆照明光源对中国传统淡彩绘画的色彩影响规律,并确定不同类型中国传统淡彩绘画的最低损害光源,以3种博物馆典型照明光源作为实验光源,分组照射中国传统淡彩绘画模型试件,对模型试件的CIELAB色度数据进行周期性测量。基于实验数据计算不同周期色差变化值,并绘制色差随曝光量的周期性衰变曲线。进而对色差值变化数据进行回归分析,拟合得到不同光源对4种淡彩绘画颜料的相对影响函数公式,提出不同光源对各类型淡彩绘画的相对影响系数。结果表明：3种照明光源对工笔淡彩绘画的影响系数为K_金卤灯：K_卤钨灯：K_WLED=1.00：0.92：0.84;对小青绿淡彩绘画的影响系数为K_金卤灯：K_卤钨灯：K_WLED=2.05：1.71：1.65;对水墨淡彩绘画的影响系数为K_金卤灯：K_卤钨灯：K_WLED=1.17：0.94：0.91。在淡彩绘画照明保护性照明光源选择时,应选择RYGB型WLED光源。

     

Microscopic, mass spectrometric and spectroscopic characterisation of the mordants used for gilding on wall paintings from three post-Byzantine monasteries in Thessalia, Greece

The main churches of three monasteries in Thessalia, Central Greece are decorated with wall paintings from the post-Byzantine period. The main goal of the present study is to offer insights into the decorative technique of mordant gilding, especially the chemical composition of the mordants and the effects on them of ageing. Light microscopic (LM) examination was carried out on samples taken from the gilded areas of the paintings to view their layer build-up. Direct temperature resolved mass spectrometry (DTMS) under electron ionisation (EI) and chemical ionisation (CI) conditions led to the identification mainly of the organic, as well as some inorganic compounds. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) gave an account of the elemental composition on selected cases. The results from samples taken from different wall paintings were compared with each other to observe their differences and similarities. Furthermore, the three churches in question are believed to have been painted by the same painter, who has only been identified in one of them. Hence, the comparison of the wall paintings as far as the mordant gilding technique is concerned provided additional evidence on the identity of the painter in the other two churches.     

Voltammetric characterization of metal sulfide particles and nanoparticles in model solutions and natural waters

Voltammetric scans in sulfidic natural waters often reveal reduction peaks in the range −0.9 to −1.35 V versus Ag/AgCl. These peaks have been attributed to iron sulfide complexes or clusters. However, sols containing CuS nanoparticles now also are known to produce reduction peaks in this range. Here we investigate the voltammetric behavior of two additional metal sulfides at the Hg electrode in 0.55 M NaCl + 0.03 M NaHCO₃ electrolyte, pH = 8.5. We show that Pb and Hg sulfides, either as suspended powders or as precipitated nanoparticles, also yield cathodic peaks between −0.9 and −1.35 V, similar to peaks obtained with CuS and FeS. For precipitated nanoparticles, the position and shape of these reduction peaks change with ageing. Freshly formed nanoparticles produce less negative reduction peaks than aged nanoparticles. Peaks from aged nanoparticles often consist of two or more superimposed reduction peaks. When all other experimental parameters are held constant, the amount of nanoparticle analyte accumulated on the electrode increases with the amount of ageing (≤1 h). Addition of EDTA or acidification followed by purging can be used to distinguish PbS nanoparticles and Fe sulfide clusters from CuS and HgS nanoparticles or from colloidal S. This test was applied to interpret −0.9 to −1.35 V reduction peaks observed in two meromictic lakes. In conjunction with other evidence, this test suggests that FeS clusters are present in one case whereas colloidal S is present in the other. Interpreting −0.9 to −1.35 V voltammetric peaks observed in sulfidic natural waters requires caution, but these peaks are potentially rich sources of information about trace metal speciation.     

Analytical Methods for the Characterization of Organic Dyes in Artworks and in Historical Textiles

Abstract

Dyes are among the most significant components in works of art and archaeological findings. In the scientific examination of historical artefacts, the identification of natural dyestuffs is a challenging task, due to the complexity of their chemical composition and the possible presence of mixtures of chromophores and degradation products. For this reason, in the last few decades, new analytical procedures and techniques have been developed and improved for the characterization of organic dyes and their identification in microsamples. This review looks at the chemical composition of natural organic dyeing materials used in the field of the cultural heritage and focuses on several analytical methods based on spectrometric and chromatographic techniques that have contributed to the study of organic dyes in works of art and archaeological findings.