材料期刊网

自润滑烧结镁基复合材料的拉伸、压缩和磨损行为

P.NARAYANASAMY , N.SELVAKUMAR

中国有色金属学报(英文版) doi:10.1016/S1003-6326(17)60036-0

采用粉末冶金方法制备石墨/二硫化钼增强镁基自润滑复合材料,并分别表征这些复合材料的显微组织、物理性能、力学性能和磨损性能.利用XRD手段鉴定复合材料中的Gr/MoS 2相.显微组织观察表明,Gr/MoS 2颗粒均匀地分散在镁基体中.在室温条件下施加载荷5 g并保持15 s,测试复合材料的显微硬度,得到所有复合材料的显微硬度为VHN 29?34.使用显微硬度、拉伸和压缩试验研究材料的力学性能,并用扫描电子显微镜分析材料的断口形貌,得到Mg?10MoS 2复合材料最高的硬度、抗压强度和拉伸强度.用销?盘式摩擦仪测试烧结复合材料的摩擦因数和磨损量.另外,通过磨损表面特征,利用SEM系统分析复合材料的摩擦磨损机制.结果表明,与石墨相比,二硫化钼的摩擦因数和磨损有所减少.

关键词: 镁合金复合材料 , 自润滑 , 粉末冶金 , 滑动磨损 , 显微组织 , 力学性能

EFFECT OF PHOTOOXIDATION ON PHOTOLUMINESCENCE OF N, N'-DIPHENYL-N, N'-DI(M-TOLYL)-BENZIDINE AND RUBRENE CODOPED PMMA THIN FILMS

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

p+-n--n结的势垒分布

赵普琴 , 杨锡震 , 李桂英 , 王亚非

液晶与显示 doi:10.3969/j.issn.1007-2780.2001.01.010

GaP∶N绿色LED发光效率的提高有赖于对其结构参数的优化。根据载流子分布的连续性，由泊松方程自洽求解，得出了半导体n--n结势垒分布的计算方法。在此基础上，计入n-区内的电位降，计算了商用发光二极管p+-n--n结构的势垒分布，为整体结构的参数优化准备了必要的条件。

关键词: 磷化镓 , 发光二极管 , 势垒

Thermodynamic Properties of FeCN and FeCBN Melts

CHEN Erbao , WANG Shijun , DONG Yuanchi , WU Baoguo , ZHOU Yun

钢铁研究学报(英文版)

The saturated solubility of carbon and nitrogen in FeCN and FeCBN melts was measured experimentally at 1 485 ℃ to obtain the activity interaction coefficients between components in these melts. A new method was used to treat experimental results. Using thermodynamic derivation and calculation, some important interaction coefficients between components in these melts were obtained.

关键词: FeCN melt;FeCBN melt;FeCB melt;interaction coefficient;thermodynamic property

Dispersion behavior of laser-synthesized Si3N4 nanopowders in N-N-dimethylformamide

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

The electronic structure and the ferromagnetic properties of Cu(mal)(DMF) (n)(mal = malonate dianion, DMF = N,N-dimethylformamide)

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

通过J/Ψ→N(N-)M衰变研究N*时的核子极点效应

沈彭年 , 梁伟红 , 邹冰松

原子核物理评论 doi:10.3969/j.issn.1007-4627.2004.02.009

研究了J/Ψ→ p(p-)π衰变过程中核子极点图的贡献,特别是由离壳效应带来的贡献.发现衰变宽度对形状因子是敏感的.在通过用J/Ψ→ p(p-)π衰变研究N*时,核子极点图作为背景道的贡献是非常重要的; 在通过J/Ψ→ p(p-)η和 p(p-)η研究N*时,核子极点图的贡献可忽略不计; 在通过J/Ψ→ p(p-)ω研究N*时,核子极点图有明显的贡献.

关键词: J/Ψ衰变 , 核子激发态

有机电致发光材料用N，N，N′，N′-四苯基联苯二胺类化合物的制备

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

原位液相催化加氢法合成N-乙基苯胺和N,N-二乙基苯胺

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

Amorphous B-C-N semiconductor

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