MICROSTRUCTURE AND PREPARATION OF Ni,Al AND Fe NANOPOWDERS

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Application of ESR Technique to Distinguish the Phase and Size of TiO_2 Powders

The commercial TiO2 nanopowder and micropowder of anatase phase and rutile phase have been characterized by X-ray diffraction(XRD) and electron spin resonance(ESR) spectroscopy.XRD patterns and ESR spectra of nano-TiO2 in rutile and anatase phases exhibit broad peaks whereas both phases of micro-TiO2 demonstrate very sharp peaks.Furthermore,the anatase phase of both particle sizes provide ESR peak at a magnetic field around 3568.25 G.On the other hand,this peak is not established in the rutile phase of both...     

Sol-Gel Synthesis and Sensing Study of Perovskite CaCu3Ti4O12 Nanopowders

CaCu₃Ti₄O₁₂ nanopowders were fabricated by a facile effective sol-gel route using tetrabutyl titanate, calcium acetate and cupric nitrate as precursors. The intermediate xerogel was characterized by thermal analyzer and the products with different calcination temperature were then studied by IR spectrum. Further X-ray diffraction, transmission electronic microscopy, high-resolution transmission electron microscopy and energy dispersive X-ray spectrum were used to characterize the prepared CaCu₃Ti₄O₁₂ nanopowders. Additionally, the obtained CaCu₃Ti₄O₁₂ nanopowders were investigated as a gas sensitive material responding to ethanol atmosphere, and it showed high sensitivity for ethanol gas.     

Production and properties of electrosprayed sericin nanopowder

Abstract

Sericin is a proteinous substrate that envelops fibroin (silk) fiber, and its recovery provides significant economical and social benefits. Sericin is an antibacterial agent that resists oxidation and absorbs moisture and UV light. In powder form, sericin has a wide range of applications in food, cosmetics and drug delivery. Asides from other techniques of producing powder, such as precipitation and spray drying, electrospraying can yield solid nanoparticles, particularly in the submicron range. Here, we report the production of sericin nanopowder by electrospraying. Sericin sponge was recovered from Bombyx mori cocoons through a high-temperature, high-pressure process, followed by centrifugation and freeze drying of the sericin solution. The electrospraying solution was prepared by dissolving the sericin sponge in dimethyl sulfoxide. We demonstrate that electrospraying is capable of producing sericin nanopowder with an average particle size of 25 nm, which is by far smaller than the particles produced by other techniques. The electrosprayed sericin nanopowder consists of small crystallites and exhibits a high moisture absorbance.     

微波水热法制备硫化锡纳米晶及其光学性质的研究

以氯化亚锡和硫化铵为前驱物采用微波水热法合成硫化锡纳米晶,采用XRD和TEM对合成物的晶型和形貌进行表征。结果表明:制备的样品为斜方晶体结构的多晶硫化锡粉体,晶粒形状为近球形。随着反应温度的升高,硫化锡纳米晶的晶粒尺寸从20 nm增至50 nm;随着反应时间的延长,硫化锡纳米晶的晶粒尺寸呈增大趋势。利用紫外可见光谱分析,硫化锡纳米晶的光学带隙约为1.61 eV。     

一步水热法制备核壳型纳米粉体研究

简述了纳米微粒表面修饰的重要性以及修饰方法，并指出制备核壳型纳米材料是一种重要的表面修饰方法。液相法制备核壳纳米粉体具有反应温度低、设备简单、能耗低的优点。而一步水热法在液相法中具有其它方法无法比拟的优越性。因此，重点讨论了一步水热法制备核壳纳米粉体的工艺流程和机理，并对一步水热法制备核壳型纳米材料进行了展望。     

Rapid gold ion recovery from wastewater by photocatalytic ZnO nanopowders

In this study, ZnO nanopowder was synthesized by solution-combustion method (SCM). The photocatalytic gold recovery efficiency by this SCM ZnO nanopowder was about 6 fold higher compared to the case by the state of the art commercial TiO₂ nanopowder. The purity of recovered gold was about 99.6% in weight% and 98.8% in atomic%. Furthermore, the ZnO nanopowder synthesis method and gold recovery process are very cost-effective. Especially, in this study it was tried to recover gold metal ions from not simulated wastewater but real plating wastewater. This technology is therefore very viable to obtain high purity gold from plating wastewater.     

纳米抗菌剂在陶瓷中的应用

把复配载银纳米抗茵剂按不同比例加入到陶瓷釉料中，涂于底釉上，经过1200℃烧成，得到表面具有抗茵性的白色高致密度的陶瓷片。表面性能测试、SEM分析和抗茵试验表明：加入纳米抗茵剂的表面釉断面气孔边缘平滑，气孔形状为圆形、大小均匀，是未加纳米抗茵剂的釉断面气孔孔径的l／3。在釉料加入纳米抗菌剂后，陶瓷表面形成超亲水膜，不渗油。在釉料中加入l％的抗茵剂，对大肠杆菌的杀菌率达到99．3％，对金黄葡萄球菌的杀菌率为100％，多组分复配抗茵剂比单组分抗茵剂杀菌效果好。     

Characterization of (PVDF + LiFePO<Subscript>4</Subscript>) solid polymer electrolyte

LiFePO₄ nanopowders (50 nm) were prepared through a simple hydrothermal process. Poly vinylidene fluoride (PVDF): LiFePO₄ complex membranes as solid polymer electrolytes were characterized. X-ray diffraction (XRD) and differential scanning calorimetric (DSC) studies show a decrease in crystalline size and crystallinity of the polymer PVDF with increasing LiFePO₄ concentration. Scanning electron micrographs show smaller spherical domains in the dry film with increased LiFePO₄ nanopowder content. Impedance measurements suggest that the ionic conductivity of (PVDF + LiFePO₄) increases with increased temperature and lithium powder concentration.     

氧化锆纳米粉体的制备及其材料的掺杂研究新进展

综述了近年来国内外学者在氧化锆纳米粉体的制备技术及其材料的掺杂改性研究方面取得的新成果.介绍了对改性共沉淀法、改性溶胶-凝胶法、放热固相法等氧化锆纳米粉体的新型制备技术以及掺杂铝、锌、铜等物质的改性氧化锆材料的研究现状.最后对氧化锆材料的发展方向进行了展望.