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1.
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
2.
王春阳 《广州体育学院学报》2001,21(1):59-61
关节软骨的损伤修复问题一直是困扰国际运动医学界的三大难题之一。过去的研究多集中于动物或成人，很少对胎儿进行研究。本对顶臀长146mm～280mm胎儿的股骨髁关节软骨最表层进行光镜观察，发现：从顶臀长146mm胎儿起关节软骨最表层就有一波浪状起伏的膜结构，随着发育，起伏减小，膜与其下分界愈来愈明确，到顶臀长280mm胎儿时已过渡成一平滑无起伏的薄层非细胞膜状结构。 相似文献
3.
Thomas K. Bader Karin de Borst Karin Fackler Thomas Ters Susan Braovac 《Journal of Cultural Heritage》2013,14(5):377-388
Mechanical properties of wood at different length scales of its hierarchical structure are governed by structural and compositional properties on smaller length scales. This opens up the possibility to use microstructural data for estimating mechanical properties, which are difficult to assess by conventional, destructive testing but are nevertheless of high relevance for conservation practice. Herein, we investigate such microstructure-mechanics relationships for a particular example, namely the load bearing archaeological oak of the Oseberg Viking ship, displayed at the Viking Ship Museum in Oslo, Norway. In order to identify the effects of degradation on the mechanical behavior and their relations to the microstructure, recent oak specimens of different geographical origin (Norway and Austria) are investigated as well. Wood exhibits a cellular structure. Its cell walls are composed of an amorphous polymer matrix consisting of lignin and hemicelluloses and embedded, stiff cellulose fibers. At the cell level, experimental studies comprised microscopic investigations of the cellular structure, chemical analyses of the composition of the cell walls, as well as nanoindentation tests on single cell walls. The same samples were also analyzed on the macroscopic level, where additionally mass density and annual ring data were measured together with ultrasonic stiffnesses. The chemical data clearly indicate deterioration in the archaeological oak, affecting mainly hemicelluloses and amorphous cellulose. At the cell wall scale, however, this does not necessarily lead to a weaker material behavior. The nanoindentation modulus, as a measure of the cell wall stiffness, was found to even increase. This is counterintuitive to our understanding of the effects of chemical degradation. It might be due to possible modification of lignin in the Oseberg oak, and thus have a stronger effect on the indentation modulus than the concurrent weakening of the interfaces between the load-carrying cellulose fibers and the connecting cell wall matrix when analyzing wood at the microscopic level. A similar effect is also observed for the transversal stiffness of macroscopic samples, which increases. In tension-dominated loading modes, however, the degradation of the interfaces is the dominant effect, resulting for example in a considerable reduction of the macroscopic stiffness in longitudinal direction. This underlines the utmost relevance of the loading condition on the remaining load-carrying capacity of degraded wood. On the macroscale, effects of the geographical origin (i.e. growth conditions) on ring characteristics of the oak tissues override the effects of degradation on the mechanical behavior. They have to be carefully extracted in order to come up with conclusions on the effect of degradation from macroscopic test results. The identified microstructure-mechanics relationships provide the basis for–in further research steps–building mathematical models describing the relations between microstructural characteristics and macroscopic mechanical properties and, thereon, for structural analyses of historical wooden objects. 相似文献
4.
Peter J.F. Harris 《Endeavour》2019,43(3):100695
This article draws attention to literary works which have been influenced by microscopy, or in which microscopy has played a significant role. The work of writers including Jonathan Swift, Voltaire, George Eliot, H. G. Wells and D. H. Lawrence is discussed. In many cases these authors had direct experience of operating microscopes and viewing the wonders of the microscopic world. However, with the increasing separation of the two cultures, recent examples of microscopy in literature are rare. 相似文献
5.
在扫描探针显微镜系统中,本文采用基于虚拟仪器的计算机控制步进电机,控制它的正转、反转及启动和停止,从而实现样品与探针的自动逼近。利用计算机通过I/O接口来直接产生各种方波信号,采用L abV IEW编程完成控制算法,以此来实现步进电机运动,提高了逼近系统的自动化性能和控制精度。 相似文献
6.
针对光学材料亚表面损伤的截面显微法检测进行了深入研究.介绍了截面显微法的基本原理以及样品制备和检测工艺流程,并对检测结果进行了分析,得出了亚表面裂纹深度与磨料粒度之间的比例关系. 相似文献
7.
论述了在常温下和在大气状态下,扫描隧道显微镜（STM）在石墨薄膜表面上的电场加工实验,并对作用机理进行了分析,认为表面结构现象生成是场蒸发效应作用的结果,其导电性受外电场力的大小和薄膜层数之间的束缚力的影响。 相似文献
8.
高水平的科研带动高质量的共享服务 总被引：2，自引：1，他引：1
清华大学电子显微镜实验室成立于1997年,是一个对校内和全社会开放的公共实验室。实验室的宗旨是“以高水平的科研工作带动高质量的技术服务、设备高效运行和资源共享”。10年来实验室在科研、公共服务和人才培养等方面都取得了较好成绩。2006年国家科技部委托清华大学以清华大学电镜实验室为基础,建设“国家科技基础条件平台-北京电子显微镜中心”。 相似文献
9.
论述了在大气状态下扫描隧道显微镜STM在石墨表面上的电场加工实验,并对作用机理进行了分析,认为表面结构的生成是场蒸发效应和化学反应(局部气化反应)的综合作用。 相似文献
10.
现代高分辨电镜和高空间分辨分析电镜,使我们可以在纳米和原子尺度研究材料的显微结构和微区成份,从而极大地加深了我们对材料的结构与性能的理解。另一方面,随着信息技术的飞速发展,计算材料学也以前所未有的广度和深度,冲击着材料研究的模式。对显微结构的研究也是如此。材料的微结构,作为组成材料的大量原子在空间中的排列,本质上是由原子间的相互作用,即化学键决定的。借助第一原理总能与电子结构计算可给出原子间成键的详尽的信息,它在显微结构及其演变的研究中有很好的应用前景。本论文将先进电子显微术与计算材料学有机地结合起来,在从纳米、原子尺度到电子尺度等多个层次对钛基金属间化合物和陶瓷(Ti3SiC2, TiC, TiAl)的结构进行了研究。 相似文献