吕艳红
,
陈吉堃
,
D?BELI Max
,
李宇龙
,
史迅
,
陈立东
无机材料学报
doi:10.15541/jim20150197
本工作提出了脉冲激光沉积法生长 Cu2Se 热电材料薄膜中维持较高的激光切削能量密度对于实现薄膜与靶材成分等比例传输的重要性。使用较高的脉冲激光能量生长的Cu2Se薄膜具有纯的a-相，并具有与靶材相近的化学组分。这主要是因为较高的激光能量可以更加有效地引起等离子体对激光-固体直接作用的屏蔽，这可以使得靶材中的铜和硒元素的激光切削量更加接近靶材的化学计量比。由于硒具有较高的蒸汽压，降低激光能量会加强激光与固体的直接作用，从而更有效地切削硒元素，导致所沉积薄膜中产生铜缺陷。进一步讨论了所使用的氩气背景气体压力对于所生长的 Cu2Se 薄膜热电性能的影响。当使用高激光能量低背景气体压力时，所生长的薄膜具有最佳的热电性能。
关键词:
Cu2Se薄膜
,
脉冲激光沉积
,
热电
,
激光能量
Scripta Materialia
Nb(4)AlC(3), a new compound belonging to the MAX phases, was discovered by annealing bulk Nb(2)AlC at 1700 degrees C. The crystal structure of Nb(4)AlC(3) was determined by combined X-ray diffraction, high-resolution transmission electron microscopy and ab initio calculations. It was reported that Nb(4)AlC(3) follows the Ti(4)AlN(3)-type crystal structure. The lattice constants are a = 0.31296 nm, c = 2.41208 nm and the atomic positions are Nb1 at 4f (1/3, 2/3, 0.0553), Nb2 at 4e (0, 0, 0.1574), Al at 2c (1/3, 2/3, 1/4), C1 at 2a (0, 0, 0) and C2 at 4f (2/3, 1/3, 0.1086). (c) 2007 Published by Elsevier Ltd. on behalf of Acta Materialia Inc.
关键词:
Nb(4)AlC(3);ceramics;crystal structure;thin-films;ti3sic2;ti4aln3;ta4alc3;microstructure;deformation;carbides;ti3alc2;growth
Journal of the American Ceramic Society
A new compound, Ti5Al2C3, is identified in the bulk sample prepared by reactive hot pressing a mixture of Ti, Al and graphite powders with a nominal molar ratio of Ti:Al:C=5:2.15:2.78 at 1580 degrees C for 1h. This compound follows the crystal structure of other MAX phases. The lattice parameters are a=0.3038nm, c=3.2261nm, and the atomic positions are Ti1 at 4f (1/3, 2/3, 0.0208), Ti2 at 4f (1/3, 2/3, 0.1778), Ti3 at 2d (2/3, 1/3, 0.25), Al at 4e (0, 0, 0.1035), C1 at 2a (0, 0, 0), and C2 at 4e (0, 0, 0.2102).
关键词:
crystal-structure;microstructural characterization;ti4aln3;ti3gec2;ta4alc3
朴燕
,
郑喜凤
,
刘维亚
,
王瑞光
液晶与显示
doi:10.3969/j.issn.1007-2780.2000.02.008
液晶显示器在信息显示技术中得到了越来越广泛的应用.作为液晶显示的主要部分之一的电源电路,直接控制提供给液晶驱动芯片的偏压.电源电路的电压的高低将直接影响液晶显示器的灰度调整和对比度的变化.MAX686是Maxim公司生产的用于提供液晶偏压的电源器件.MAX686能够转换液晶所需的正极性或负极性偏压的集成电路,有很强的灵活性,其内部有6bit的数模转换器,可用数字方式调整输出电压.因此,可以很方便地用软件或硬件来调整输出电压.MAX686的高集成度为其节省了体积,减小了功耗,增加了电池的寿命,使其非常适用于电池供电的便携式仪器中.
关键词:
液晶驱动
,
电源电路
,
正极性
,
负极性
Journal of the American Ceramic Society
A new-layered compound, (Ti(0.5)Nb(0.5))(5)AlC(4), which belongs to MAX phases was discovered. The new-layered carbide was synthesized by reactive hot pressing of Ti, Nb, Al, and C powders. The crystal structure was determined by the combination of X-ray diffraction and transmission electron microscopy analyses, which consists of a 5(Ti, Nb)-C bond chain linked by an Al layer. The lattice parameters are a=3.100 A, c=28.89 A, with Ti(Nb)1 at (0, 0, 0), Ti(Nb)2 at (1/3, 2/3, 0.0877), Ti(Nb)3 at (2/3, 1/3, 0.1723), Al at (0, 0, 0.25), C1 at (2/3, 1/3, 0.0463), and C2 at (0, 0, 0.1566).
关键词:
crystal-structure;ternary ceramics;c system;carbide;ta4alc3;microstructures;ti3gec2;ti4aln3;solids
