C.T. Chang T.Y. Yeh R.K. Shiue C.S. Chang
材料科学技术（英文）
Microstructural evolution of infrared vacuum brazing CP-Ti using two Ti-based braze alloys, Ti-15Cu-15Ni and Ti-15Cu-25Ni, have been investigated. The infrared brazed joint consists of eutectic Ti2Cu/Ti2Ni intermetallic compounds and Ti-rich matrix. The eutectic Ti2Cu/Ti2Ni intermetallic compounds are disappeared from the joint after 1h annealed at 900oC. In contrast, the depletion rate of both Cu and Ni from the braze alloy into CP-Ti substrate at 750oC annealing is greatly decreased as compared with that annealed at 900oC. Blocky Ti2Cu/Ti2Ni phases are observed even if the specimen is annealed at 750oC for 15h. Because the Ni content of the Ti-15Cu-25Ni braze alloy is much higher than that of the Ti-15Cu-15Ni alloy, the amount of eutectic Ti2Cu/Ti2Ni phases in Ti-15Cu-25Ni brazed joint is more than that in Ti-15Ci-15Ni brazed joint. However, similar microstructural evolution can be obtained from the infrared brazed joint annealed at various temperatures and/or time periods for both filler metals.
关键词:
Journal of Applied Physics
The magnetic properties of R2Co14B1-xCx (x=0, 0.5 and R=Y, Sm) compounds have been studied by measuring the temperature dependence of the easy- and hard-magnetization curves on magnetically aligned samples between 1.5 and 300 K for Y2Co14(B,C) and at 4.2 K for Sm2Co14(B,C). The magnetic anisotropy of Y2Co14B increases due to the substitution of C for B, whereas the saturation magnetization decreases. Between 1.5 and 300 K, the anisotropy field of Y2Co14B0.5C0.5 increases about 2 T and the Co moment decreases about 0.05mu(B). The anisotropy field Of Sm2Co14B also increases upon C substitution and the saturation magnetization decreases slightly. The ac susceptibilities of both SM2Co14B and Sm2Co14B0.5C0.5 exhibit anomalies that may arise from a spin reorientation within the basal plane.
关键词:
nd2fe14b;exchange;nd2co14b;r2fe14b;field
Physica C-Superconductivity and Its Applications
Superconducting cuprate fluorides Nd0.7Sr1.3Cu(O,F)(4-delta) with T-c = 44 K were obtained by solid phase fluorination of the T-structure Nd0.7Sr1.3CuO4-gamma at low temperature (200-300 degrees C) using CuF2 as fluorinating reagent. The oxyfluoride has K2NiF4 structure with S.G. I4/mmm as its precursors, but the evident lattice expansions were observed. The a-axis expands from 3.7257(2) Angstrom to 3.9288(5) Angstrom and c-axis from 12.8240(3) Angstrom to 12.9630(2) Angstrom. No trace of SrF2 was detected in these fluorinated products. XRD and magnetic measurement revealed that the superconductivity in the fluorinated products originated from the oxyfluorides with reduced CuO2 plane and in the presence of the apical anion.
关键词:
hole concentration;copper;route;a=ca;tc
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
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
Materials Letters
Secondary M,C precipitation was investigated in K40S cobalt-base alloy after 100 h aging at 950 degreesC. The results showed that it was closely related to the tungsten-rich zones inherited from the as-cast condition and the degeneration of the primary M7C3 carbide. A direct element reaction, 6M + C --> M6C, in which C comes from the decomposition of the M7C3 carbides, is suggested as the mechanism of secondary M6C precipitation in K40S alloy. (C) 2001 Elsevier Science B.V. All rights reserved.
关键词:
M6C precipitation;aging;M7C3 carbide;superalloy
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
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
