377 resultados para proton emission
Resumo:
Up-conversion luminescence characteristics under 975 nm excitation have been investigated with Tb3+/Tm3+/Yb3+ triply doped tellurite glasses. Here, green (547 nm: D-5(4) --> F-7(4)) and red (660 nm: D-5(4) --> F-7(2)) up-conversion (UC) luminescence originating from Tb3+ is observed strongly, because of the quadratic dependences of emission intensities on the excitation power. Especially, the UC luminescence was intensified violently with the energy transfer from the Tm3+ ions involves in the Tb3+ excitation. To the Tb3+/Tm3+/Yb3+ triply doped glass system, a novel up-conversion mechanism is proposed as follows: the energy of (3)G(4) level (Tm3+) was transferred to D-5(4) (Tb3+) and the 477-nm UC luminescence of Tm3+ was nearly quenched. (C) 2006 Elsevier B.V. All rights reserved.
Resumo:
The earliest Chinese ancient glasses before the West Han Dynasty (200 BC) from different regions are studied. The glass samples were unearthed from Hunan, Hubei, Yunnan, Sichuan, Guizhou, Guangdong and Xinjiang of China. The chemical composition of these glasses samples is analyzed by proton induced X-ray emission (PIXE) technique, energy dispersive X-ray fluorescence (EDXRF) method and inductively coupled plasma atomic emission spectrometry (ICP-AES). It is shown that the glass chemical compositions belong to barium-lead silicate BaO-PbO-SiO2, potash soda lime silicate K2O (Na2O)-CaO-SiO2 (K2O/Na2O > 1), soda potash lime silicate Na2O (K2O)-CaO-SiO2 (K2O/Na2O < 1) and potash silicate K2O-SiO2 glass systems, respectively. The origins of the earliest Chinese ancient glasses are discussed from the archaeological and historical points of view. These four types of Chinese ancient glasses were all made in Chinese territory using local raw materials. The glass preparation technology was related to the Chinese ancient bronze metallurgy and proto-porcelain glaze technology. The glass technology relationship between the East and the West is analyzed at the same time.
Resumo:
质子激发X射线荧光(proton induced X-ray emission,PIXE)技术是一种高灵敏度、非破坏性、多元素定量测定的分析方法。采用外束PIXE技术对内蒙古地区和博山出土的一批古代玻璃的化学成分进行了定量测定。结果表明:内蒙古地区出土的玻璃中,西周时期的玻璃珠是含有少量K2O和CaO助熔剂的釉砂,其主要成分为SiO2;汉代的玻璃珠属于PbO—SiO2玻璃;多数元代的玻璃制品和部分北魏时期的玻璃珠属于K2O—CaO—SiO2玻璃。博山出土的元末明初的玻璃基本为KzO-CaO—SiO2系玻璃
Resumo:
结合外束质子激发X荧光(proton induced X-ray emission,PIXE)和能量色散X射线荧光(energy dispersive X-ray emission,EDXRF)分析技术,对中国新疆、湖北、四川、广东出土的古代镶嵌玻璃珠的化学成分进行了检测.结果表明:新疆拜城克孜尔墓地出土的西周-春秋时期镶嵌玻璃珠为CaO-MgO-SiO2玻璃,战国时期中国境内的PbO-BaO-SiO2和Na2O-CaO-SiO2镶嵌玻璃珠是同时存在的.本文亦对相关问题进行了一些讨论,并提出了部分今后的工
Resumo:
采用改进的外束质子激发x射线荧光、电感耦合等离子体原子发射光谱分析等技术,对广西合浦地区出土的一批汉代古玻璃样品的化学成分和结构特性等进行了检测。结果表明:两汉时期,合浦地区的古代玻璃存在K2O—SiO2、PbO-BaO-SiO2、PbO—SiO2、Na2O-K2O-PbO-SiO2、(Na2O)K2O-CaO—SiO2等多种类型,但绝大多数为K2O—SiO2玻璃。表面风化可引起K2O-SiO2玻璃表面K2O等助熔剂的流失和富硅层的形成。综合化学成分以及器型特征,认为我国汉代K2O—SiO2玻璃制造技术可
Resumo:
abstract {Proton induced X-ray emission (PIXE) technique is an effective method for the chemical composition analysis of ancient glass samples without destruction. Chemical composition of the ancient glass samples dated from the Warring States Period (770-476 B.C.) to the Six Dynasties Period (220-589 A.D.), which were unearthed in Sichuan area, was quantitatively determined by the PIXE technique. The results show that the glass Bi (disc) and the glass eye beads of the Warring States Period all belong to the PbO-BaO-SiO2 system. According to the composition and shape, we infer that these glass Bi and eye beads were made in China. Whereas, the chemical compositions of the glass ear pendants and beads of the Six Dynasties Period are varied, including K2O-CaO-SiO2, K2O-SiO2 and other glass systems. Based on the obtained results and those from literatures, some questions related to the technical propagation of the ancient Chinese glass are discussed.}
Resumo:
利用质子激发X射线荧光(PIXE)、X射线衍射(XRD)、扫描电子显微镜(SEM)以及激光拉曼光谱(LRS)技术对几个来自中国新疆、俄罗斯、加拿大和新西兰等地的软玉样品的进行了岩石矿物学特征分析,从成分组成和微观织构方面比较了各地软玉的不同特征.实验结果显示了软玉作为透闪石质玉石,随着Fe2O3含量的增加,逐步向阳起石过渡.中国和田玉以其特有的毛毡状纤维交织结构,形成了均匀细腻、油脂光泽的表面特征.无破损成分分析方法为研究贵重的古玉样品提供了技术支持.