Controlled Growth Morphology of Porous Nanocrystal Iron Oxide by Electrodeposition

Fe(II) was deposited into the bottom of the mesopores of highly ordered large caged cubic mesoporous silica by electrodeposition. And the deposited Fe mesoporous silica thin film was treated by 1%―4% HF to remove the SiO2 template and then calcined. It was found that nanowire bundles, dendritic plates of porous iron oxide, dense parallel backbones of porous iron oxide were obtained at 1.4―-1.6 V and 0.08―0.1 mol/L electrolyte concentration after calcinations; the dendritic pattern of porous iron oxide film ...     

X射线荧光光谱法测定蛇纹石成分

蛇纹石因其外表分化呈灰白、石红色网纹,似蛇皮而得名,主要用作炼钢熔剂、耐火材料、提取氧化镁和多孔氧化硅等.它的质量优劣直接影响钢铁冶炼时造渣性的优劣.     

关于氧化硅烯结构和电子性质的第一性原理研究

利用基于广义梯度近似的密度泛函理论,本文研究了二维氧化硅烯的几何结构和电子特性.结果显示,随着氧含量的增加,氧原子更加倾向于以-（Si2O2）x-键的形式排列在硅烯表面.每一个-（Si2O2）x-键都会使临近氧原子的六个硅原子处在同一表面,并且四个Si-O键构成一个与之相垂直的平面.当所有的硅原子都转化成sp3杂化后,氧化硅烯会形成最稳定的全氧化结构并具有0.46 eV的带宽.部分氧化的硅烯结构具有从0.30 eV到0.38 eV的较小带宽,这些较小的带宽非常吻合较早时的关于氧化硅纳米带的带宽的实验数值（0.35 eV）,并且说明离子化的Si-O键和共价性的Si-Si键共存导致了较小带宽的出现.     

离子束反应溅射沉积SiO2薄膜的光学特性

 主要研究采用离子束反应溅射（RIBS）制备SiO2薄膜的折射率、消光系数、化学计量比与氧气在氩氧混合工作气体中含量及其沉积速率的关系。研究结果表明：RIBS制备的SiO2薄膜在0.63 μm处折射率n= 1.48,消光系数小于10-5;随着沉积速率的增加,薄膜的折射率和消光系数随之变大,当沉积速率超过0.3 nm/s,即使是在纯氧环境溅射,折射率值也不低于1.5;通过对红外透射光谱的主吸收峰位置研究得到沉积的SiO2薄膜为缺氧型,化学计量比不超过1.8,且红外吸收峰位置和SiO2折射率存在对应关系,因此在不加热衬底情况下使用RIBS制备SiO2薄膜时,会限制沉积速率的提高。     

氨基功能化介孔吸附剂的一步合成及其重金属吸附性能

以聚甲基含氧硅氧烷(PMHS)、正硅酸乙酯(TEOS)和氨丙基三甲氧基硅烷(APTMS)作为反应前驱体,在无需传统结构导向剂的溶胶-凝胶体系中制备了介孔结构发达的氮基功能化凝胶吸附剂,并采用元素分析、固体核磁共振、傅里叶红外光谱、低温氮气吸附/脱附、透射电镜和热重分析等手段对产物结构性能进行了表征.氮气吸附和透射电镜测...     

电感耦合等离子体-原子发射光谱法测定铁精矿粉中的氧化硅

通过系统考察铁精矿粉的分解方法以及熔剂的配比实验,确定铁精矿粉分解完全的实验方法,并进行了光谱干扰、放置时间、基体效应、精密度、准确度和对照等实验.与分光光度法和重量法相比此方法准确、快速.试样熔融方法与铁矿石的国家标准分析方法相比更适合于铁精矿粉的分析.测定范围在0.20％-10.00％之间.     

TiO_2-SiO_2纳米粒子的合成及二级散射光谱法测定核糖核酸

采用溶胶-凝胶法制备了TiO2-SiO2纳米粒子.通过X-射线衍射谱、透射电子显微镜等对纳米粒子进行了表征.研究了TiO2-SiO2纳米粒子与核糖核酸(RNA)的相互作用,建立了基于纳米粒子与RNA吸附反应,二级散射光谱法测定痕量RNA的新方法.方法的线性范围是0.005～5 mg/L; 检出限为1.46 μg/L.方法用于RNA合成样品的测定,回收率为99.4%～103.9%;相对标准偏差为019%～0.24%.     

Oxidation of silicon surface with atomic oxygen radical anions

The surface oxidation of silicon （Si） wafers by atomic oxygen radical anions （O- anions） and the preparation of metal-oxide-semiconductor （MOS） capacitors on the O-oxidized Si substrates have been examined for the first time. The O- anions are generated from a recently developed O- storage-emission material of [Ca24Al2sO64]^4＋·4O^- （Cl2A7-O^- for short）. After it has been irradiated by an O- anion bean： （0.5 μA/cm^2） at 300℃ for 1-10 hours, the Si wafer achieves an oxide layer with a thickness ranging from 8 to 32 nm. X-ray photoelectron spectroscopy （XPS） results reveal that the oxide layer is of a mixture of SiO2, Si2 O3, and Si2O distributed in different oxidation depths. The features of the MOS capacitor of 〈Al electrode/SiOx/Si〉 are investigated by measuring capacitance-voltage （C - V） and current-voltage （I - V） curves. The oxide charge density is about 6.0 × 10^1 cm^-2 derived from the （C - V curves. The leakage current density is in the order of 10^-6 A/cm^2 below 4 MV/cm, obtained from the I - V curves. The O- anions formed by present method would have potential applications to the oxidation and the surface-modification of materials together with the preparation of semiconductor devices.     

Explanation of Effect of Added Water on Dye-Sensitized Nanocrystalline TiO2 Solar Cell： Correlation between Performance and Carrier Relaxation Kinetics

Time-resolved mid-IR transient absorption spectroscopy is employed to explore the mechanism of improving the performance of dye-sensitized TiO2 solar cell （DSSC） when a certain amount of H2 0 is added into the electrolyte. The relaxation kinetics of dye-sensitized TiO2 nanocrystalline film and the corresponding DSSC performance are investigated under different conditions. It is found that the interracial charge recombination is retarded and electron injection efficiency is increased in the water vapour and in the electrolyte when D20 is added. The values of open-circuit photovoltage Voc and the short-circuit photocarrent Jsc of the cells are linearly correlated to the product of the two decay time constants. We also observed that Voc well correlates with electron injection efficiency. It provides a preliminary microscopic account for the function of the added water in improving the performance of DSSCs.     

PVP改性氧化硅溶胶的微结构和流变性

以正硅酸乙酯为前驱体,聚乙烯吡咯烷酮（PVP）为聚合物改性添加剂,在碱性条件下制备氧化硅溶胶,通过小角X射线散射测量了改性溶胶的微结构参数,辅以动态光散射观测溶胶颗粒生长,研究了聚合物量、碱催化剂量和水量对溶胶颗粒度、分形特征以及流变性的影响规律.由于PVP链中强极性的分子内酰胺基团和氧化硅颗粒表面的羟基形成氢键,致使溶胶颗粒被聚合物链包裹,严重阻碍了溶胶颗粒的生长,使凝胶时间延长,流变性发生变化,同时对溶胶颗粒的微结构产生影响.