Calcium hydroxytitanate formed in the Bayer digestion process of Chinese diasporic bauxite was studied. Interplanar spacings of calcium hydroxytitanate crystal were determined by XRD analysis. Only one endothermic pea...Calcium hydroxytitanate formed in the Bayer digestion process of Chinese diasporic bauxite was studied. Interplanar spacings of calcium hydroxytitanate crystal were determined by XRD analysis. Only one endothermic peak occurs at 550-560°C on the DTA curve. IR spectrometry has revealed that hydroxyl exists in calcium hydroxytitanate instead of crystal water. Observation under SEM has indicated that the crystal grains are in the shape of regular hexagonal plates 2-8 μm in edge length and less than 1 μm in thickness. The influences of various digestion conditions on the formation and transformation of calcium hydroxytitanate and other Ca-Ti-containing compounds such as lime addition, content and distribution state of TiO2 in bauxite, digestion temperature and retention time were studied.展开更多
Splat foils with 30-35 μm thickness and spum ribbon with 50-55 μm thickness of Mo-4Th-0.4B and Mo-8Th-0.8B were made by arc melt hammer-anvil and melt spinning techniques. Both alloys have high hardness and a strong...Splat foils with 30-35 μm thickness and spum ribbon with 50-55 μm thickness of Mo-4Th-0.4B and Mo-8Th-0.8B were made by arc melt hammer-anvil and melt spinning techniques. Both alloys have high hardness and a strong age hardening response, especially Mo-8Th-0.8B. The precipitates associated with age hardening were ThB4(tetragon) and Mo2B (C16, BTC). The times for reaching a age hardening peak for both alloys are not the same and depended on the precipitation extent of Th and B solutes from the metastable solid solution. Grain refinement was observed. The work indicates that new high strength Mo alloys can be developed by rapid solidification.展开更多
Have developed a Bi-Pb-Sr-Ca-Cu-O superconductor with an onset Tc of 108K and a zero resistance temperature Tco of 104K. There are at least five different phases: the high Tc and low Tc ones and three minor ones. The ...Have developed a Bi-Pb-Sr-Ca-Cu-O superconductor with an onset Tc of 108K and a zero resistance temperature Tco of 104K. There are at least five different phases: the high Tc and low Tc ones and three minor ones. The high Tc and low Tc phases have the face - centered orthorhombic structure with a = 0.540nm, b = 0.545nm, c = 3.669nm and a = 0.540nm b = 0.546nm, c = 3.077nm, respectively. The former has the superstructure of 3.24nm, and the latter has the superstructure of 2.7nm and is incommensurate in the b direction.展开更多
近年来,矿物自动定量分析系统已广泛应用于地质、石油、矿业、冶金、考古和环境等领域,而中国对该系统在岩矿科研领域的应用则刚刚起步。文章以捷克泰思肯电镜公司(TESCAN)的全自动矿物分析系统TIMA(TESCAN Integrated Mineral Analyzer...近年来,矿物自动定量分析系统已广泛应用于地质、石油、矿业、冶金、考古和环境等领域,而中国对该系统在岩矿科研领域的应用则刚刚起步。文章以捷克泰思肯电镜公司(TESCAN)的全自动矿物分析系统TIMA(TESCAN Integrated Mineral Analyzer)为例,简述了该系统的基本原理、硬件和软件组成。TIMA是基于扫描电镜和能谱分析的岩石矿物全自动化定量分析系统,能同时进行极高分辨率的背散射与X射线能谱快速成像,且配备专业的矿物处理软件辅助分析结果并生成报告。该系统在岩矿研究方面主要有以下方面的功能和应用:(1)获取岩矿样品的整体形态和矿物及元素的种类、含量及分布;(2)查明矿物的结构构造、共生、连生和包裹关系特征;(3)提供特定矿物和亮相搜索模块,可以快速准确寻找细小目标矿物和金、银和铂等贵金属以及稀有、稀土金属。TIMA系统将分析测试和数据处理分开,可满足不同用户需求,对矿物成分和结构的定量解析达到微米的尺度,相对于传统光学显微镜和扫描电镜在地学微区信息提取方面具有不可代替的优势。文章以榴辉岩、蚀变蛇纹岩和花岗岩-伟晶岩的全岩矿物组成和成分,古沉积物反映沉积环境的演化,稀土矿石的元素赋存状态和矿物共生组合关系,金、银和锆石等特定矿物的寻找,变形和出溶结构,锆石和石英的阴极发光联用以及优化选矿工艺流程等具体实例展示了TIMA在岩矿研究中的应用。展开更多
The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites （6 traffic, 5 industrial, and 6 residential sites）, and 3 suburban sites to assess the lead pollution in fine par...The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites （6 traffic, 5 industrial, and 6 residential sites）, and 3 suburban sites to assess the lead pollution in fine particulate matter （PM2.5） after phasing out leaded gasoline in Shanghai. Compared with Pb levels reported in other places, the Pb pollution in Shanghai is still serious after phasing out leaded gasoline, which remains at high concentration range （213-176 ng/m^3） in PM2.5 in winter. Significant spatial variation of Pb concentrations and strong seasonal variation of higher Pb concentration in winter than that in summer were detected. The size distribution of Pb in particulate matter has a unimodat mode that peaks at approximately 0.154-1.59 μm particle diameter, indicating that Pb is mainly concentrated in fine fraction. Lead in the fine fraction is enriched by a factor of 103-104 relative to Pb abundance in crust. Eight categories of Pb pollution sources were identified in the PM2.5 in the winter of 2007 in Shanghai. The important emission sources among them are vehicle exhaust derived from combustion of unleaded gasoline, metaUurgic industry emission, and coal combustion emission.展开更多
文摘Calcium hydroxytitanate formed in the Bayer digestion process of Chinese diasporic bauxite was studied. Interplanar spacings of calcium hydroxytitanate crystal were determined by XRD analysis. Only one endothermic peak occurs at 550-560°C on the DTA curve. IR spectrometry has revealed that hydroxyl exists in calcium hydroxytitanate instead of crystal water. Observation under SEM has indicated that the crystal grains are in the shape of regular hexagonal plates 2-8 μm in edge length and less than 1 μm in thickness. The influences of various digestion conditions on the formation and transformation of calcium hydroxytitanate and other Ca-Ti-containing compounds such as lime addition, content and distribution state of TiO2 in bauxite, digestion temperature and retention time were studied.
文摘Splat foils with 30-35 μm thickness and spum ribbon with 50-55 μm thickness of Mo-4Th-0.4B and Mo-8Th-0.8B were made by arc melt hammer-anvil and melt spinning techniques. Both alloys have high hardness and a strong age hardening response, especially Mo-8Th-0.8B. The precipitates associated with age hardening were ThB4(tetragon) and Mo2B (C16, BTC). The times for reaching a age hardening peak for both alloys are not the same and depended on the precipitation extent of Th and B solutes from the metastable solid solution. Grain refinement was observed. The work indicates that new high strength Mo alloys can be developed by rapid solidification.
文摘Have developed a Bi-Pb-Sr-Ca-Cu-O superconductor with an onset Tc of 108K and a zero resistance temperature Tco of 104K. There are at least five different phases: the high Tc and low Tc ones and three minor ones. The high Tc and low Tc phases have the face - centered orthorhombic structure with a = 0.540nm, b = 0.545nm, c = 3.669nm and a = 0.540nm b = 0.546nm, c = 3.077nm, respectively. The former has the superstructure of 3.24nm, and the latter has the superstructure of 2.7nm and is incommensurate in the b direction.
文摘近年来,矿物自动定量分析系统已广泛应用于地质、石油、矿业、冶金、考古和环境等领域,而中国对该系统在岩矿科研领域的应用则刚刚起步。文章以捷克泰思肯电镜公司(TESCAN)的全自动矿物分析系统TIMA(TESCAN Integrated Mineral Analyzer)为例,简述了该系统的基本原理、硬件和软件组成。TIMA是基于扫描电镜和能谱分析的岩石矿物全自动化定量分析系统,能同时进行极高分辨率的背散射与X射线能谱快速成像,且配备专业的矿物处理软件辅助分析结果并生成报告。该系统在岩矿研究方面主要有以下方面的功能和应用:(1)获取岩矿样品的整体形态和矿物及元素的种类、含量及分布;(2)查明矿物的结构构造、共生、连生和包裹关系特征;(3)提供特定矿物和亮相搜索模块,可以快速准确寻找细小目标矿物和金、银和铂等贵金属以及稀有、稀土金属。TIMA系统将分析测试和数据处理分开,可满足不同用户需求,对矿物成分和结构的定量解析达到微米的尺度,相对于传统光学显微镜和扫描电镜在地学微区信息提取方面具有不可代替的优势。文章以榴辉岩、蚀变蛇纹岩和花岗岩-伟晶岩的全岩矿物组成和成分,古沉积物反映沉积环境的演化,稀土矿石的元素赋存状态和矿物共生组合关系,金、银和锆石等特定矿物的寻找,变形和出溶结构,锆石和石英的阴极发光联用以及优化选矿工艺流程等具体实例展示了TIMA在岩矿研究中的应用。
基金supported by the National Natural Sci-ence Foundation of China (No. 10775172, 10675159)the Major Project of Knowledge Innovation Program of Chinese Academy of Sciences (No.KJCX3.SYW.N3)This work has been performed under the approval of the Photon Factory (PF) Program Advisory Committee (No.2007G502)
文摘The Pb-monitoring program was extended for 6 years from 2002 to 2007 at 17 representative urban sites （6 traffic, 5 industrial, and 6 residential sites）, and 3 suburban sites to assess the lead pollution in fine particulate matter （PM2.5） after phasing out leaded gasoline in Shanghai. Compared with Pb levels reported in other places, the Pb pollution in Shanghai is still serious after phasing out leaded gasoline, which remains at high concentration range （213-176 ng/m^3） in PM2.5 in winter. Significant spatial variation of Pb concentrations and strong seasonal variation of higher Pb concentration in winter than that in summer were detected. The size distribution of Pb in particulate matter has a unimodat mode that peaks at approximately 0.154-1.59 μm particle diameter, indicating that Pb is mainly concentrated in fine fraction. Lead in the fine fraction is enriched by a factor of 103-104 relative to Pb abundance in crust. Eight categories of Pb pollution sources were identified in the PM2.5 in the winter of 2007 in Shanghai. The important emission sources among them are vehicle exhaust derived from combustion of unleaded gasoline, metaUurgic industry emission, and coal combustion emission.
