Surface Investigation of Metal Threads and Solid Metals of Ottoman Textiles in the Topkapi Palace Museum

ABSTRACT

We analyzed 53 historical textile samples from a collection of caftans and brocades dating between the sixteenth and nineteenth century in the Topkapi Palace Museum (TPM) by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). Data were collected on the type, dimensions, elemental composition, and level of corrosion. The technique is presented in this work as an efficient and micro-destructive tool for the characterization of the structure of historical metal threads. SEM-EDX analysis for different energies was performed on a selection of gold and silver threads belonging to the historical textiles. The results were interpreted via laboratory prepared samples of gilt Ag and sulfur reacted Ag at different thicknesses for Au and Ag₂S layers respectively. A series of Au–Ag alloys for different Au/Ag ratios were prepared for comparative analysis. The threads were made of metal strips wound around a silk core. Metal wires and flat strips were also used. The use of differential energies allowed for differentiating strips and wires made of homogeneous silver and gold alloys from the ones coated with a thin gold layer. Analysis of EDX data revealed that the Au film thickness was very thin (10–60?nm). Formation of Ag₂S layers over the thin Au film as thick as 1.5?µm was taking place. Formation of thinner Ag₂S layers over non-gilt Ag suggested different reaction mechanisms for gilt and non-gilt cases.     

“微课+翻转”混合式教学探索与实践--以“金属材料综合实验”课程为例

人工智能、大数据、云计算等新兴技术推动了教育技术的变革,MOOC、微课、翻转课堂等新的教学模式应运而生。以“金属材料综合实验”课程为例,以提升学生的应用能力、思辨能力和创新能力为教学目标,尝试将微课、翻转课堂融合并应用于一线教学,从课程内容优选、教学形式设计与实施、课程考核方式、教学质量评估与持续改进四个方面进行思考,提出优选课程内容的方法,分析开展微课、翻转课堂混合式教学的可能性,探讨注重过程评价的课程考核方式,介绍了金属材料综合实验课程教学实践经验。     

毕节铅、锌矿区重金属污染及优势植物累积特性分析--以毕节妈姑和金钟铅、锌矿区为例

重金属的开采和冶炼不仅破坏生态平衡,而且严重威胁人类的健康。以毕节地区2个铅锌矿为研究对象,采用现场采样、室内分析的方法,调查研究了该地区土壤及优势植物中重金属含量。结果表明：研究区土壤主要受到Pb、Zn、Cu、Cd四种重金属污染,其中,Cd污染最为严重,Pb、Zn为轻度污染。优势植物重金属含量测定表明,野艾蒿属于重金属富集型植物,苦苣菜属于规避型植物,马刺蓟属于根部囤积型植物。以上几种优势植物对重金属均具有一定的耐性,可以作为铅锌矿区弃地植物修复的优选物种。     

学校体育与学生心理健康研究

学校体育对学生心理健康具有较大的促进作用. 学校体育在促进学生心理健康发展中应注意教师观念与时俱进、加强校园体育文化建设、面向全体学生、以发展为主、体育运动适度.     

美国社会科“探究弧”:内容、特征及启示

美国在《为大学、职业及公民生活做准备的社会科州立标准框架:提高K-12年级公民、经济、地理和历史学科严谨性的指导》(C3框架)中提出了推动探究在课程实施中落地的指导框架——"探究弧"。该框架围绕问题、概念、证据和行动四个维度对社会科课程的实施进行指导,意在通过探究增进学生对知识的理解,提升学生相关的学习能力,使学生为更好地参与未来生活做好准备。我国德育课程可以考虑借鉴"探究弧"将学生发展作为核心的理念及其在课程方案设计、跨学科教学实施和教学过程中多种能力融合培养等方面的经验,提升德育课程教学的效果。     

An investigation into the cause of corrosion on indoor bronze sculpture

Abstract

Corrosion noted on a number of nineteenth and twentieth century indoor bronze sculptures in the collection of the National Gallery of Canada was the cause for a major condition survey of its Canadian, American, and European bronzes. The results led to a comprehensive study, which included material analysis. This article outlines the steps undertaken to determine the extent and type of corrosion, its possible cause(s), and potential remediation. The survey included 136 bronzes, of which 40 were selected for an in-depth study. Indoor air quality tests of the current building, housing the collection since 1988, were carried out. The dossiers and database records of the selected sculptures were reviewed to investigate their condition, treatment, and storage history. The metal, patina, and corrosion products were subjected to analysis. More areas of corrosion were generally associated with predominantly green patinas and chloride-containing compounds identified in either patina or corrosion samples. The most frequently identified compounds in the patina samples were atacamite, a copper(II) chloride hydroxide, and cuprite, a copper(I) oxide. The most frequently identified compounds in the corrosion samples were atacamite and rouaite, a copper(II) hydroxide nitrate. The analysis determined that the current environment is not contributing to the surface alterations of the sculptures; however, past storage conditions, chemical residues from artificial patination, and likely casting residues are the main causes of the current condition.     

解析变换下曲线的曲率与弧长

推导出了在单叶解析变换下,像曲线的曲率与弧长的计算公式．     

电子束焊接技术现状及发展

介绍电子束焊接技术原理及特点,综合论述电子束焊接技术的国内外研究发展情况及其前景。     

金属离子水解常数的计算

在改进失屏参数计算方法的基础上,根据失屏参数与许多金属元素化学性质相关联,研究得到只用一个参数计算各类金属离子水解常数的方法。