Y.D.Xiao
,
W.X.Li
,
D.Jacovkis
,
M.T.Clavaguera-Mora
,
J.Rodriguez-Viejo
,
N.Clavaguera
金属学报(英文版)
Rapidly solidified Al87Ni7Cu3Nd3 metallic glasses, prepared by using melt spinning, were treated under both isothermal and non-isothermal regime. The amorphous rib-bon and the annealed samples were closely examined by means of differential scan-ning calorimetric, conventional X-ray diffraction and high resolution transmission electron microscopy with selected-area electron diffraction, with special interest in pri-mary crystallization into α-Al nanocrystalline particles, in order to understand struc-tural characteristics of Al-based amorphous/nanocrystalline alloys, and nucleation and grain growth mechanism on the nanometer scale during primary crystallization. The results show that, the as-prepared ribbons are fully amorphous and homogeneous in the micron scale, but contain high density of quenched-in clusters or crystallite embryos. Primary crystallization mainly leads to formation of two-phase mixture of α-Al crystal and residual amorphous phase. The annealed ribbons exposed isother-mally at 110℃ for 5, 130 minutes and heated continuously up to less than 310℃ at 40℃/min consist of large amount of α-Al fec crystal nanoparticles dispersed uni-formly in an amorphous matrix. However, a very little amount of finer orthorhombic Al3Ni intermetalics particles exist in the annealed ribbons heated up to 310℃. During primary crystallization, the leading kinetic mechanics to impede growth of the α-Al crustal is soft impinaement, instead of geometric impinqement.
关键词:
rapid solidification
,
null
,
null
Y.B. Hou
金属学报(英文版)
In this paper, the PMMA films doped with N,N'-diphenyl-N,N'-di(m-tolyl)-benzidineand rubrene were fabricated by spin coating, and the effect of photooxidation onthe photoluminescence of the doped PMMA thin films was investigated. The resultsshowed that under the irradiation of 350nm UV light, N,N'-diphenyl-N,N'-di(m-tolyl)-benzidine can sensitized rubrene and results in the enhancement in the photooxrationof rubrene. The effect of photooxidation on the photoluminescence from rubrene w asmore obvious. Both lifetime measurement and in situ measurement of photolumines-cence showed that rubrene molecules exist in two chemical surroundings.
关键词:
photoluminescence
,
null
Ceramics International
The dispersion behavior of Si3N4 nanopowders prepared by laser-induced gas-phase reaction in a non-aqueous solvent, N-N-dimethylformamide (DNIF) was studied, and triethanolamine (TEA) was selected as a dispersant. One hundred and sixty-six-day sedimentation tests were used to study the stability of the suspensions. Photon correlation spectroscopy was employed to measure the sizes of aggregates and coagulation rates. TEA was proved an effective dispersant for nano-Si3N4 in DMF, presoaking treatment could enhance the effect of the dispersant. TEA 1.0 wt.% referred to Si3N4 and a 1-month-presoaking gave the best dispersion, the dispersion stability was improved from several minutes to several months, and the average size of the aggregates was reduced to about a twenty-fifth. The dispersion ability of TEA was believed being related to its strong affinities both to the powder surface and to the solvent. (C) 2002 Elsevier Science Ltd and Techna S.r.l. All rights reserved.
关键词:
Si3N4;dispersion;nanopowders;N-N-dimethylformamide;triethanolamine;composite;powders
Journal of Magnetism and Magnetic Materials
We present first-principles study on the magnetic properties of the 3D metal-ligand coordination polymer [Cu(mal)(DMF)]n within the framework of density functional theory ( DFT) by using the full-potential linearized augmented plane-wave (FP-LAPW) method. The total and partial density of states ( DOS), the band structure, and the atomic spin magnetic moment of [ Cu( mal)( DMF)] n are calculated. The calculation reveals that [ Cu( mal)( DMF)] n is a ferromagnetic semiconductor. The calculated spin magnetic moment is about 1.000 mu B per molecule, which is in agreement with experimental value. (c) 2007 Elsevier B.V. All rights reserved.
关键词:
first-principles;electronic structure;ferromagnetic properties;complexes;acid
柴生勇
,
安忠维
液晶与显示
doi:10.3969/j.issn.1007-2780.2001.02.007
通过Ulmann缩合反应合成了在有机电致发光（OEL）显示器件上有使用前景的四苯基联苯二胺类空穴传输材料N， N′-二苯基-N， N′-双(3-甲基苯基)-［1， 1′-联苯］-4， 4′-二胺、 N， N′-二苯基-N， N′-双(4-甲基苯基)-［1， 1′-联苯］-4， 4′-二胺和N， N， N′， N′-四苯基-［1， 1′-联苯］-4， 4′-二胺。 对产品从混合物中分离的方法作了改进。 其产率及含量分别为85%、 97.6%； 95%、 98.5%； 70 %、 98.1% 。 对3种化合物均用红外光谱进行了表征。
关键词:
制备
,
四苯基二胺化合物
,
空穴传输材料
,
有机电致发光
沈颖旎
,
罗智伟
,
严新焕
催化学报
以硝基苯为原料, Pt/γ-Al2O3为催化剂,乙醇水溶液为溶剂和氢供体,采用原位液相加氢一步法合成了N-乙基苯胺和N,N-二乙基苯胺. 采用低温N2吸附-脱附、电感耦合等离子体发射光谱、X射线衍射、程序升温化学吸附和透射电子显微镜等对Pt/γ-Al2O3催化剂进行了表征,并考察了所制备催化剂的原位液相加氢性能. 结果表明,在温度为503 K、压力为5.0 MPa、空速为3.2 h-1、溶剂水含量为30%以及硝基苯浓度为8%的反应条件下,在Pt/γ-Al2O3催化剂上原位液相加氢合成N-乙基苯胺及N,N-二乙基苯胺有较好的结果,硝基苯转化率达到100%, N-乙基苯胺和N,N-二乙基苯胺的总收率达到99.5%. 讨论了硝基苯原位液相加氢合成N-乙基苯胺和N,N-二乙基苯胺的反应机理.
关键词:
铂
,
氧化铝
,
硝基苯
,
原位液相催化加氢
,
N-乙基苯胺
,
N
,
N-二乙基苯胺
,
乙醇
Journal of Applied Physics
Amorphous BC2N powders were prepared by mechanical milling with hexagonal boron nitride and graphite as starting materials. A bulk amorphous BC2N compound was produced by sintering the as-milled amorphous BC2N powders in a vacuum of 10(-5) Torr at a temperature of 1470 K. The conductivity measurement for the bulk amorphous BC2N compound showed that it behaves as a semiconductor with band gap energy of 0.11 eV for temperatures ranging from room temperature to 560 K and a semimetal for temperatures between 560 and 740 K. The mechanism of the formation of the amorphous BC2N powders is discussed. (C) 1998 American Institute of Physics.
关键词:
bc2n
