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Lidia Armelao Arianna Bassan Renzo Bertoncello Guido Biscontin Sergio Daolio Antonella Glisenti 《Journal of Cultural Heritage》2000,1(4)
The study of the interaction between silica glass and saturated Ca(OH)2 solutions can be a useful approach to resolve the problem of the adhesion between lime-sand mortar and clay bricks. Since it is reasonable that the silica–calcium hydroxide system well simulates a brick–mortar system, experimental observations concerning the interaction of silica glass and this strong basic solution should be of value for the comprehension of the chemical reactions that could take place at the mortar–brick interface, maybe affecting the adhesion between the two building materials. We demonstrated the effects of saturated Ca(OH)2 solutions on commercial pure silica glass (fused silica) and on silica films obtained via a sol–gel process by means of dip-coating. Silica samples were dipped in the solutions at different temperatures (room temperature, 60 and 80 °C) and at different time intervals (1 and 21 h) and then they were analysed by means of surface techniques: X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and atomic force microscopy (AFM). It has been shown that Ca(OH)2 reacts with the silica glass network. The experimental results clearly show a very different behaviour of sol–gel silica with respect to fused silica, probably because of their different nanostructure. Many problems concerning the interaction of silica and Ca(OH)2 are still to be solved, but the results of this research strengthen the idea that adhesion between lime-sand mortar and clay bricks is caused not only by carbonation of calcium hydroxide contained in the mortar, but even by some chemical reactions involving the brick constituents and calcium hydroxide itself. The final products, calcium silicates, may induce a chemical continuity between lime-sand mortar and clay bricks. 相似文献
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Discoloured 18-carat gold decorations from Sweden have been analysed by scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray electron spectroscopy (XPS)/electron spectroscopy for chemical analysis (electron spectroscopy).The original gold composition was close to 75% gold, 13% silver, and 12% copper. After manufacture, many details were boiled in sulphuric acid. As a consequence of this, the surfaces are irregular and porous with a gold concentration around 90% and with less than 1% copper. With XPS the outermost 10–20 atomic layers could be examined. No copper was present here, and the silver concentration was significantly higher. Also carbon, sulphur, oxygen, and (in one case) chlorine were present. The valence numbers indicated that gold only occurred in its metallic state, while silver (as Ag+) was preferably associated with sulphur to form black silver sulphide (Ag2S). The grey discolorations are basically due to silver sulphide and organic dirt. Sometimes green, violet, and ‘copper-shining’ colours occur, presumably as a result of light refraction phenomena. 相似文献
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The Powerhouse Museum in Sydney, Australia houses the world's most significant and comprehensive collection of Speedo swimwear and accessories. The museum has identified a problem with the long-term storage of certain Spandex/Lycra® items where the elastane fibre has degraded leading to oil formation. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) determined that most of these garments were manufactured using nylon-elastane fibres, and the elastane component comprises polyetherurethane or polyesterurethane polymers. Certain polyesterurethanes are known to be vulnerable to hydrolysis, and this was confirmed for a subset of the collection using two chemical testing protocols, and a thermal testing protocol that reproduced the oil formation. A polyetherurethane garment in the collection was unchanged by these tests. The oil from the thermal testing was confirmed as a breakdown product of the polyester component of the elastane fibre, using ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy, and time-of-flight secondary ion mass spectrometry. The study demonstrates the value of ATR-FTIR for minimally invasive identification of elastane fabrics that may require specialized storage in a humidity-controlled environment. 相似文献
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Xu Li-heng Chen Zhi-chun Li Yang-mei Lu De-shui Lin Xian-fu Yuan Jun 《浙江大学学报(A卷英文版)》2002,3(5):567-569
Pepsin was assembled on the surface of prepared poly (ethylene terephthalate) (PET-NH3
+) substrates. The composition and structure of the pepsin/PET-NH3
+ assembling films in different condition were characterized by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy
(AFM). 相似文献
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对国内应用较为广泛的建筑节能保温材料,在节能保温以及防火安全方面进行了分析,与国外建筑保温材料应用现状进行了比较,指出了EPS及XPS在防火安全方面存在的问题,提出了建筑节能体系的建立和建筑节能保温材料阻燃性能规范制定的建议,提出新型PU复合保温墙体的研究目标。 相似文献
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外墙外保温系统有明显的优越性,目前在欧美国家广泛应用。本文对比研究了几种常见的外墙外保温系统在五种不同情况下的保温性能。研究表明,XPS板保温性能优于EPS板的保温性能,EPS板薄抹灰保温系统和EPS无网保温系统的保温效果明显优于有网系统和机械固定系统,保温砂浆的保温效果高于EPS板薄抹灰保温系统的保温效果,同一种保温系统下保温材料的厚度对保温效果提高不明显。 相似文献
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利用浸渍法制备了Pd/Al2O3催化剂,采用X射线衍射(XRD)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)研究了Pd在载体Al2O3中的分布状态和价态.结果表明纳米尺寸的Pd颗粒主要以单质形式高度分散在载体Al2O3上,部分呈氧化态. 相似文献