丙烯酸法制备La_(0.75)Sr_(0.25)MnO_3纳米粉体

采用丙烯酸法合成了La0.75Sr0.25MnO3(LSM)纳米粉体,探讨了合成过程中丙烯酸与交联剂用量、热处理温度等合成条件对合成粉末的物相与形貌的影响,对合成的粉末进行了XRD、SEM、TG-DTA、FTIR分析.结果显示:在丙烯酸:交联剂:LSM粉末质量比为0.3:0.03:1,热处理温度为950℃的条件下,可得到单相、高纯、均匀、少团聚的LSM纳米粉末;电性能测试表明,LSM烧结体在700℃附近电导率达到较高值(约180 S·cm-1).可见,这种新颖的丙烯酸法较其他化学法更绿色环保,制备的粉体电学性能优异,适合用于SOFC单电池阴极.     

高速电弧喷涂NiCrBMoFe/BaF2·CaF2涂层的摩擦磨损性能研究

利用高速电弧喷涂技术制备了NiCrBMoFe和NiCrBMoFe/BaF₂·CaF₂两种复合涂层.两种涂层均含非晶相与纳米晶相,非晶相质量百分数分别达45%和33%.NiCrBMoFe涂层中纳米晶相弥散分布在非晶母相中;NiCrBMoFe/BaF₂·CaF₂涂层纳米晶相以团聚形态存在.检测了两种涂层的摩擦磨损性能.在常温下,NiCrBMoFe和NiCrBMoFe/BaF₂·CaF₂两种涂层的摩擦系数分别为0.5和0.375,后者比基体18Cr₂Ni₄WA的摩擦系数下降了25%,耐磨性能优异.在高温摩擦磨损条件下,NiCrBMoFe/BaF₂·CaF₂涂层也具有良好的耐磨性能.在450 ℃左右,涂层中BaF₂·CaF₂固体润滑相会析出涂层表面,形成一层低摩擦系数的润滑转化膜,使涂层具有良好的减摩润滑作用.     

分子磁学--一个新兴的前沿研究领域

分子磁学是一个新兴的前尚交叉学科。文章简要介绍了该学科的主要研究内容,并对近年来发展最快的几个研究热点,即分子内磁耦合作用与分子磁工程、分子基铁磁体、单分子磁体、自旋转换配合物和生物体系内磁耦合作用,作一简要评述和展望。     

Raman scattering of nanocrystalline silicon embedded in SiO2

Raman scattering of nanocrystalline silicon embedded in SiO2 matrix is systematically investigated. It is found that the Raman spectra can be well fitted by 5 Lorentzian lines in the Raman shift range of 100-600 cm-1. The two-phonon scattering is also observed in the range of 600-1100 cm-1. The experimental results indicate that the silicon crystallites in the films consist of nanocrystalline phase and amorphous phase; both can contribute to the Raman scattering. Besides the red-shift of the first order optical phonon modes with the decreasing size of silicon nanocrystallites, we have also found an enhancement effect on the second order Raman scattering, and the size effect on their Raman shift.     

纳米引晶法选择性生长金刚石薄膜

通过传统的光刻工艺和纳米引晶技术,在抛光的单晶Si衬底上形成带有 超细金刚石纳米粉的引晶图案,并利用该图案与抛光Si处金刚石成核密度的巨大差异,实现 金刚石薄膜的高选择比生长。该方法具有工艺简单、沉积效率高、选择比高、对底无任何损 伤等优点。同时,这种方法很容易在不同衬底上实现金刚石薄膜的大面积选择性生长。     

染料敏化纳米太阳能电池

本文介绍了染料敏化纳米太阳能电池的结构和原理,对纳米TiO₂膜、敏化染料、空穴传输材料的研究进展进行了综述.     

Study of Nanocrystalline Diamond Film Deposited Rapidly by 500 W Excimer Laser

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FABRICATION AND CHARACTERIZATION OF THE SIZE-CONTROLLED AND PATTERNED nc-Si DOTS

A new method of phase-modulated excimer laser crystallization is adopted to fabricate the patterned nanometer-sized crystalline silicon (nc-Si) dots within the sandwiched structure (a-SiN_x:H/a-Si:H/a-SiN_x:H) films. The results of transmission electron microscopy, electron diffraction and Raman scattering show the ultra-thin and single-layer nc-Si films were patterned in the lateral direction and the size of crystallites is controlled by the thickness of as-deposited a-Si film in the longitudinal direction. The effects of the laser energy density on the structures of the samples and the crystallization mechanism are discussed.