New insights into brazilwood lake pigments manufacture through the use of historically accurate reconstructions     

Tatiana Vitorino  Leslie Carlyle  Vanessa Otero 《文物保护研究》2016,61(5):255-273

A multi-analytical approach for the study of brazilwood and its lake pigments was carried out based on historically accurate reconstructions. Recipes for brazilwood lakes from the fifteenth century technical text Livro de como se fazem as cores and the Winsor & Newton nineteenth century colourman's archive were reproduced and compared. Both primary sources allowed for the successful preparation of brazilwood lake pigments with colours that vary from light pink to dark red. The main steps and ingredients for the manufacture of these pigments were common in both sources, particularly the addition of Al³⁺ in the form of alum, and calcium carbonate (chalk). Reconstructions revealed that the latter acts as a pH buffer and filler, controlling the pH at which the lake pigment precipitates. The main difference between the two sources is that the nineteenth century recipes give the quantities for all ingredients, the precise temperatures and time, and achieved higher relative pigment yields (75% versus 45%). Full chemical characterisation of the reconstructions provided detailed information on the individual steps in the pigment manufacture and revealed that the presence of calcium sulphate dihydrate (gypsum) in the final pigment was a result of its formation in situ. Infrared, reflectance, and fluorescence spectroscopy proved to be essential and complementary techniques: while infrared was used to characterise additives and binders, reflectance and fluorescence data were fundamental for identifying the chromophore. The pigments and paints produced can now be used as standards for the identification and investigation of brazilwood lake pigments found in artworks.  相似文献   

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

Birgit Angelika Schmidt  Martin Andreas Ziemann  Simone Pentzien  Toralf Gabsch  Werner Koch  Jörg Krüger 《文物保护研究》2016,61(2):113-122

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.  相似文献   

在数学教学中融入探索研究--关于发现型讨论式教学的案例与思考     

李坤琼 《重庆职业技术学院学报》2004,13(3):170-170,174

面对知识经济时代,数学教学中应该融入探索研究思想.本文从具体的案例出发,阐述了在教学活动中如何进行探索研究思想的渗透.  相似文献   

Active recovery of the finger flexors enhances intermittent handgrip performance in rock climbers     

Jiří Baláš  David Giles  Jan Kodejška  Michaela Panáčková  Simon Fryer 《European Journal of Sport Science》2016,16(7):764-772

This study aimed to (1) evaluate the effect of hand shaking during recovery phases of intermittent testing on the time–force characteristics of performance and muscle oxygenation, and (2) assess inter-individual variability in the time to achieve the target force during intermittent testing in rock climbers. Twenty-two participants undertook three finger flexor endurance tests at 60% of their maximal voluntary contraction until failure. Performances of a sustained contraction and two intermittent contractions, each with different recovery strategies, were analysed by time–force parameters and near-infrared spectroscopy. Recovery with shaking of the forearm beside the body led to a significantly greater intermittent test time (↑ 22%, P?P?P?相似文献   

现阶段高等师范院校分散教育实习存在的问题及其对策   总被引：3，自引：0，他引：3  

林浩亮  杨少卿 《韩山师范学院学报》2005,26(5):98-100

该文分析了现阶段高等师范院校教育实习实行分散实习模式存在的突出问题,并探讨了完善分散实习的若干对策.  相似文献   

太赫兹时域光谱技术   总被引：1，自引：0，他引：1  

孟田华  赵国忠 《雁北师范学院学报》2007,23(3):14-17

介绍了太赫兹时域光谱技术的优势,太赫兹时域光谱系统及太赫兹时域光谱技术的原理和应用.  相似文献   

光泵磁共振中的双射频子吸收   总被引：1，自引：0，他引：1  

邸淑红  石凤良 《张家口职业技术学院学报》2001,14(2):40-42

给出一种测量地磁的新方法，解释了实验中出现的双射频子吸收现象。  相似文献   

生物大分子的共振光散射分析     

王峰 《忻州师范学院学报》2005,21(2):11-14

文章介绍了共振光散射技术及其在生物大分子定量分析中的应用,并讨论了其发展方向和前景。  相似文献   

个性·矛盾·悲鸣--论苏曼殊的感伤之旅   总被引：1，自引：0，他引：1  

张琴凤 《江西教育学院学报》2005,26(5):91-93

苏曼殊作为一个神秘、浪漫的文学天才,在近代中国东/西杂陈的剧烈动荡中,走过了他短暂而凄凉的一生.他孤独、矛盾的心灵在世纪末的风雨中痛苦挣扎、绝望哀鸣,这种浓郁的感伤情愫已融入他生命的深层,并成为他浪漫生命之旅中的一朵哀艳之花.他的感伤之旅主要包括个性主义反抗的矛盾性;与英国浪漫主义诗人拜伦的情感共鸣及个体反抗的精神畸变;浪漫感伤情怀在小说中的深入呈现等.  相似文献   

频散效应对铁磁共振曲线的影响     

王合英  孙文博  张慧云  茅卫红 《实验技术与管理》2007,24(11):28-30,42

在铁磁共振实验中，通过铁磁共振曲线测量共振线宽十分重要，因为它表示铁磁材料磁损耗的大小。频散效应对铁磁共振曲线有明显的影响，该文从理论上分析了频散效应的物理本质以及它对铁磁共振曲线的影响，阐述了测量共振线宽的具体实验方法。  相似文献