材料期刊网

EXAFS STUDY OF THE SHORT RANGE STRUCTURE OF NANOCRYSTALLINE BCC-Fe80Cu20 SOLID SOLUTION

Y.Z. Yang , X.J. Bai , T.C. Kuang

金属学报(英文版)

The structure of bcc-Fe80 Cu2o solid solution produced by mechanical alloying of theelemental bcc-Fe and fcc-Cu powders has been studied using X-ray diffraction and theextended X-ray absorption fine structure (EXAFS) techniques. The disappearance ofelemental Fe and Cu X-ray diffraction (XRD) peaks and the presence of bcc structuralXRD peaks illustrate the formation of a nanocrystalline single-phase bcc-Fe80 Gu20solid solution. From the EXAFS results, the clear observation of Cu atoms taking onbcc coordination in the solid solution and Fe atoms remaining bcc structure furtherverifies the reality of atomic alloying between Fe and Cu atoms and the lattice changeof Cu from fcc to bcc. However, the supersaturated bcc solid solution is not chemicallyuniform, i.e., some regions are rich in Fe atoms and other regions rich in Cu atoms.

关键词: mechanical alloying , null , null , null

Mechanism of the dynamic thermal expansion of bismuth-based high-T-c superconductors

International Journal of Thermophysics

The dynamic process of thermal expansion (DPTE) of Bi-based high-T-c ( HTC) superconductor samples (Bi2Sr2Ca2Cu3O10, T-c = 105 K) is studied theoretically. The abnormal expansion behavior in the superconducting and normal stairs are of relevance to the energy absorption and pairing mechanisms.

关键词: dynamic process of thermal expansion;energy absorption;high-T-c;superconductors

The vortex morphology model of ultrasonic attenuation in the mixed state of high-T-c superconductors

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

This paper presents the vortex morphology model concerning the ultrasonic attenuation in the mixed state of high-T-c superconductor. This model pointed out that under different magnetic field and temperature, different vortex morphology appeared in the high-T-c superconductors. There are three factors that can determine ultrasonic attenuation, which are temperature, magnetic field and anisotropy of superconductors' structures. (C) 2003 Elsevier B.V. All rights reserved.

关键词: vortex morphology;ultrasonic attenuation;high-T-c superconductor

利用C-545T超薄层多层结构的白光器件

丁桂英 , 姜文龙 , 汪津 , 王静 , 王立忠 , 常喜 , 张刚 , 王红梅 , 赵晓红

液晶与显示 doi:10.3969/j.issn.1007-2780.2008.02.019

为了探讨(3-545T超薄层的发光特性,设计了结构为:ITO/2T-NATA(20 nm)/NPBX(20 nm)/C-545T(d nm)/BCP(8 nm)./Alq(40 nm)/LiF(0.5 nm)/Al的绿光器件.结果表明,随着C-545T层厚度d的增加,器件的亮度和效率均下降,这是由于C-545T染料的浓度淬灭效应引起的.在此基础上,制备了基于C-545T超薄层为发光层之一的多层结构的白光器件,器件结构为:ITO/NPBX(30 nm)/Rubrene(0.2 nm)/NPBX(5 nm)/DPVBi (20 nm)/NPBX(4 nm)/C-545T(0.1 nm)/Alq(30 nm)/LiF(0.5 nm)/Al.在驱动电压为16 V时,其最大亮度达到12 320 cd/m2,对应的色坐标为(0.32,0.40),在电压为4 V时,最大光功率效率达到了3.45 lm/w.

关键词: 有机电致发光器件 , 超薄层 , 效率

Trend in crystal structure of layered ternary T-Al-C carbides (T = Sc, Ti, V, Cr, Zr, Nb, Mo, Hf, W, and Ta)

Journal of Materials Research

Layered ternary T-Al-C ceramics containing early transition metal Sc, Zr, and Hf, crystallize with the T (n)Al(3)C(n+2) formula, while others containing neighbor elements Ti, V, Cr, Nb, Mo, W, and Ta yield the T(n+1),AIC(n) formula. Ternary T(n)Al(3)C(n+2) ceramics are structurally characterized by NaCl-type TC slabs being separated by Al(4)C(3)-type AlC layers. In the present study, we suggest that the ability of forming the T(n)Al(3)C(n+2) carbide could be traced back to the structure mismatches between the TC, A14C3 and T(n)Al(3)C(n+2) compounds. Ternary carbides following the T(n)Al(3)C(n+2) formula experience small lattice mismatches and strain energies. Moreover, the discrepancy between crystal structures of T(n)Al(3)C(n+2) and T(n+1)AlC(n) is interpreted by lattice mismatch and the produced strain energy for the ternary T-Al-C ceramics. We also present close relationships between the atomic radii of transition metal and lattice mismatch, as well as the strain energy. The proposed method is not only helpful to explain the trend in crystal structure of T-Al-C based ceramics, but may be also general to predict the crystal structure of layered compounds constructed by alternatively stacked structural units.

关键词: zr2al3c4;zr3al3c5;systems;phases;solids;energy

不同T300级碳纤维轴棒法C/C复合材料的导热性能

冯阳阳 , 崔红 , 李瑞珍 , 吴书峰

宇航材料工艺 doi:10.3969/j.issn.1007-2330.2011.02.029

选取两种国产T300级PAN基碳纤维,轴棒法制备4D预制体,以高温煤沥青为前驱体,采用液相浸渍-炭化以及石墨化相结合的技术制备C/C复合材料(密度≥1.95 g/cm<'3>),研究了C/C复合材料从室温(RT)到800℃的热导率及其影响因素.研究表明,在实验温度范围内C/C复合材料的热导率随温度升高而降低,由于原材料自身特性和预制体编织结构具有方向性,使C/C复合材料的导热性能表现出各向异性,径向热导率明显高于轴向;密度高、开孔率小、石墨化程度高的C/C复合材料由于晶粒间连通状态好,微晶结构趋于完整,材料的热导率增大;以低压热处理为最终处理工艺的C/C复合材料热导率略有提高;采用国产T300级与东丽,1300碳纤维制备的C/C复合材料的热导率相当.

关键词: 碳纤维 , C/C复合材料 , 轴棒法 , 热导率

T6963C点阵式液晶显示模块的应用研究与编程

李银华 , 姬光锋

液晶与显示 doi:10.3969/j.issn.1007-2780.2008.05.008

介绍了基于T6963C控制器、并带有32 kbyte显示缓冲区的点阵式液晶显示模块wG240128E-TMI-VZ(LCD Module,LCM),给出了T6963C与单片机之间的硬件接口电路,对液晶模块文本显示模式与图形显示模式的各自特性和实用方法做了详细的分析.通过由C语言编写的程序,使其各自的特性和实用方法得以生动的体现,并重点介绍了图形模式下菜单的灵活开发过程.经工程实际使用,结果表明:该方法可行,稳定性高,便于移植,对其他人机交互的界面设计具有极大的参考价值.

关键词: T6963C , 文本显示 , 图形显示 , 屏幕网格化定位 , 反显

基于MSP430的内置T6963C液晶显示模块控制技术

宋俊杰 , 原冬梅 , 金海龙 , 申慧鹏

液晶与显示 doi:10.3969/j.issn.1007-2780.2010.01.021

介绍了内置T6963C的液晶显示模块与MSP430单片机的硬件设计和软件设计技术,详细阐述了其文本、图形及文本属性显示方式的软件设计思想,给出了显示程序实例,对模块实现了很好的控制.

关键词: MSP430 , T6963C , 液晶显示 , SYB240128A

HIGH T_c SUPERCONDUCTOR YBa_2 Cu_3 O_x SYNTHESIZED BY UNIDIRECTIONAL REACTION

FAN Zhanguo , JI Chunlin , WANG Kuihan , CUI Chuanmeng , LIU Sulan , Northeast University of Technology , Shenyang , China

金属学报(英文版)

A unidirectional reaction for synthesis of the high T_c superconductor YBa_2Cu_3O_x has been proposed, Its T_c is 90-94.5 K and △T is 1 K. The phase relationships in the system Y_2BaCuO_5-Y_2Cu_2O_5-CuO-YBa_2Cu_3O_x were studied and discussed.

关键词: unidirectional reaction , null , null

5000 t/d水泥熟料生产线C1～C5旋风筒气相数值模拟

董立龙 , 耿宗俊 , 赵蔚琳

硅酸盐通报

采用Fluent软件模拟某5000 t/d水泥熟料生产线C1～C5级旋风筒气相冷流场的速度和压力.模拟过程中气相冷流场采用RNG k-ε湍流模型.结果表明,该生产线的旋风筒结构合理,旋风筒内气体流动符合流体运动规律;旋风筒内气体速度从上往下逐渐减小;旋风筒内静压值沿径向由外向内逐渐降低;内筒的中心轴线附近静压最低,出现负值.

关键词: 旋风筒 , 气相 , 数值模拟 , k-ε湍流模型