Baohong JIN
材料科学技术（英文）
The SiC fiber was prepared by chemical vapour depostion, which consists of tungsten core, SiC layer and carbon coating. The microstructure of the fiber was investigated using Raman spectroscopy, illustrating SiC variation in different region of the fiber. The result shows that the SiC layer can be subdivided into two parts in the morphologies of SiC grains; their sizes increase and their orientations become order with increasing distance from the fiber center. It is demonstrated that the mount of free carbon in the fiber is responsible for the variation of SiC grains in sizes and morphologies. The analysis of Raman spectra shows that the predominant β-SiC has extensive stacking faults within the crystallites and mixes other polytypes and amorphous SiC into the structure in the fiber.
关键词:
Raman spectra
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null
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null
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null
LIU Miaoxiu ZHOU Peifang CHEN Nianyi Shanghai Institute of Metallurgy
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Academia Sinica
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Shanghai
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ChinaLI Yu Shanghai University of Science and Technology
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Shanghai
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ChinaKE Jiajun Institute of Chemical Metallurgy
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Academia Sinica
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Beijing
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China
金属学报(英文版)
The anionic species of the SiO_2-containing sodium aluminate solutions prepared by different methods have been investigated by Raman spectra and ultraviolet spectra.It was found that these solutions have different SiO_2-containing anions.The solution prepared by leaching in- dustrial sinter of soda-lime sintering process contains polvsilicate ions with Si-O-Si radicals.
关键词:
silicate anion
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null
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null
LIU Miaoxiu CAO Yilin CHEN Nianyi Shanghai Institute of Metallurgy
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Academia Sinica
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Shanghai
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ChinaZHUANG Zhicheng Shanghai Jiaotong University
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Shanghai
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China Professor
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Shanghai Institute of Metallurgy
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Academia Sinica
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Shanghai 200050
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China
金属学报(英文版)
The constitution of high-caustic ratio and highly concentrated sodium aluminate solutions has been investigated by Raman spectra method.By comparison with the Raman spectra of crystalline solids of Ca_3[Al(OH)_6]_2 and Ba_2[Al_2(OH)_(10)],it can be concluded that AI(OH)_6~(3-)ion and perhaps its polymers may be formed in these solutions.
关键词:
high caustic ratio
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null
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null
刘剑红
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陈美华
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吴改
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宫旎娜
人工晶体学报
分别选用辽宁瓦房店原生矿产出金刚石、湖南砂矿产出金刚石、CVD合成金刚石、高温高压合成金刚石各1颗,采用红外光谱、高分辨率X射线衍射、拉曼光谱和正交偏光显微观察的分析方法,对其晶体质量进行了研究.通过比较金刚石1332.5 cm-拉曼本征峰的实际位移与理论位移,四颗金刚石均存在一定的内应力,高温高压合成金刚石的内应力小于其它三颗金刚石;金刚石拉曼本征峰的半高宽比对表明,四颗金刚石均存在较多晶格缺陷,其中湖南砂矿产出金刚石缺陷明显;采用双轴晶ω扫描方式测试了四颗金刚石{004}面的摇摆曲线,并估算其晶面族的晶面间距,结果显示高温高压合成金刚石{004}面的晶面间距大于其它三颗金刚石,可能是因孤氮所致;由金刚石摇摆曲线半高宽计算出内部平均位错密度值表明,高温高压合成金刚石最低,而瓦房店产出的金刚石内部平均位错密度最大,且含有亚晶界,这一结果与其异常双折射现象一致.
关键词:
金刚石
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晶体质量
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摇摆曲线
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拉曼光谱
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位错密度
徐超
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卢佃清
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邵理堂
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刘学东
材料热处理学报
采用高温固相法制备了Sr0.96Al2O4∶Eu0.02,Dy0.02,B0.08长余辉发光材料.研究了两步退火工艺中第二次退火温度对其晶体结构、激发光谱、发光光谱、余辉衰减特性、拉曼光谱和热释光光谱的影响.结果表明,随着第二次退火温度的升高,DySr陷阱中的电子浓度逐渐增加,发光动力学级次逐渐增大,这有利于提高长余辉特性;样品的拉曼光谱峰值随退火温度的变化与VO··浓度随退火温度的变化一致,这一点验证了长余辉发光材料的电子陷阱模型的有效性.在余辉测试时间内,第二次退火为1400℃×6 h的样品具有最大的余辉亮度,这源于它具有最大的DySr·陷阱中的电子浓度以及适中的时间衰减常数.
关键词:
铝酸盐
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长余辉发光材料
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电子陷阱模型
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拉曼光谱
李永涛
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滕晓雪
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汪帅
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李坤芳
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方婷
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李兴鳌
材料导报
利用溶胶-凝胶法成功制备了BiFeO3和Bi0.95Eu0.05 FeO3粉末样品,并讨论了温度和Bi离子的含量对样品制备的影响.铁电性和磁性测量显示:与BiFeO3样品相比,稀土(Eu)离子掺杂的BiFeO3样品的磁性和铁电性有很大提高.Raman谱数据分析得出,Eu离子掺杂引起了BiFeO3样品的局域结构的改变.Eu离子掺杂促使BiFeO3样品的磁性提高归因于局域结构改变导致了BiFeO3样品中的自旋轮摆结构的破坏,最终使样品的磁性提高.
关键词:
多铁性材料
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铁电性
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磁性
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拉曼谱
杜光超
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孙朝晖
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鲜勇
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陈海军
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景涵
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尹丹凤
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唐红建
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2015.05.008
以五水硝酸铋(Bi(NO3)3·5H2O)及偏钒酸铵(NH4VO3)为原料,利用TG-DSC对固相煅烧法制备钒酸铋的动力学进行研究.结果表明:不同升温速率下,反应均经历两个阶段,第一阶段的DSC峰值温度为400.67～425.95 K,反应同时在固、液两相中进行;第二阶段的DSC峰值温度为516.86～551.57 K,为固相反应;两个阶段的反应均涉及到体系副产物的分解及产物晶型的转变与完善.分别通过Flynn-Wall-Ozawa及Kissinger模型确定出两个阶段反应的动力学参数.第一阶段,表观活化能Ea1=86.56 kJ/mol,频率因子A1=4.49×1010 min-1;第二阶段,表观活化能Ea2=103.11 kJ/mol,频率因子A2 =4.12×109 min-1.
关键词:
钒酸铋
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固相焙烧法
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动力学
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TG-DSC
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拉曼光谱
