共查询到19条相似文献,搜索用时 62 毫秒
1.
本工作是用X射线衍射法观察合金AgAuZn_2的有序化过程。样品首先从600℃淬炼,然后在100℃再经不同时间的熟炼处理。样品在熟炼状态,几乎全部的Zn原子都占据了它们的适宜位置,Ag和Au原子占有适宜位置的几率则较小些。随着熟炼时间的增加,Ag,Au原子作有序的排列,而不影响Zn原子的位置。 在有序畴长大的初期阶段,从不同衍射线所求出的有序畴大小是不同的。但它们随着熟炼长大,最后却几乎达到同一线性大小。原子的有序化和有序畴的长大同时进行,但在有序畴达到稳定大小以前,有序度早已达到了稳定程度。 相似文献
2.
3.
4.
本文讨论了SO5 SU2 SU2 U1 U1及SO5 U1 U1的VCS表示.计算了SO5 U2 U2的约化矩阵元,并利用K矩阵技术确定了SO5权的多重度. 相似文献
5.
用自洽LMTO-ASA方法研究了ScH2及HfH2的电子结构,毋需在面心晶格的八面体中心位置上加入一个额外的球作为muffin-tin势的修正,关于ScH2本结果与Peterman及Harmon的计算结果及光电子谱结果十分一致;除去21的位置处在Fermi能级之下,因而在ScH2中H也可能占据八面体位置。HfH2状态密度的大致轮廓定性上与光电子谱结果是符合的。H原子带有1.2—1.3个电子电荷。
关键词: 相似文献
6.
7.
研究了Tb0.3Dy0.7Fe2合金在压磁和磁 弹性效应中的磁畴偏转和磁导率特性. 基于Stoner-Wolhfarth 模型能量极小原理, 绘制了自由能与磁畴偏转角度的关系曲线, 研究了压应力和磁场载荷作用下磁畴角度的偏转特性, 计算分析了不同载荷作用下磁畴偏转的磁导率特性, 并与实验数据进行比较论证. 研究表明,应力和磁场的作用都将使磁畴方向[111]和[111]发生角度跃迁, 直观有效地解释了材料巨磁致伸缩效应的机理; 应力和磁场作用下磁畴的偏转将使材料磁导率呈减小趋势, 其中磁场能对磁导率的影响大于应力能, 这一现象在小载荷作用下尤为明显. 实验结果表明, 磁导率的计算数据与实验数据符合得较好, 验证了计算方法的正确性. 理论分析对Terfenol-D磁畴偏转模型的完善 和磁化过程中磁滞回线的绘制非常有意义. 相似文献
8.
9.
主要讨论了电子束蒸发SiO2/HfO2薄膜的面形控制和损伤性能。研究了电子束蒸发工艺参数对薄膜应力以及面形的影响;分析了制备工艺对薄膜吸收、节瘤缺陷密度的影响,测量了制备薄膜的损伤阈值。研究结果表明:调整SiO2蒸发时的氧分压可以有效地将薄膜的应力控制在-250~-50 MPa。同时采用金属Hf蒸发可以显著地将节瘤缺陷密度从12.6 mm-2降低至2.7 mm-2,同时将损伤阈值从30 J/cm2提高至55 J/cm2。 相似文献
10.
The infrared spectra of the 2ν1, 2ν2 and 2ν3 overtones of perchloryl fluoride, FClO3, have been recorded at high resolution using monoisotopic pure samples. Four symmetric top species have been investigated: F35Cl16O3, F37Cl16O3, F35Cl18O3 and F37Cl18O3. The vi = 2, i = 1, 2, 3 vibrationally excited states are totally symmetric, so these overtones correspond to parallel bands of medium/weak intensity, centered from 2010 to 2120 cm−1 (2ν1), from 1390 to 1430 cm−1 (2ν2) and from 1070 to 1100 cm−1 (2ν3). Most of the bands are unperturbed and their analysis was straightforward. The band origins, the rotational and centrifugal molecular constants in the v1 = 2, v2 = 2 and v3 = 2 states have been determined, with standard deviations of the fits from 0.00024 to 0.00067 cm−1. The 2ν1 overtones of F35Cl16O3 and F37Cl16O3 are perturbed by an A1/E Coriolis resonance between the v1 = 2 state and one E component of the v4 = 1, v6 = 2 manifold. The 2ν2 of F37Cl18O3 is perturbed by the same kind of interaction involving the v1 = v6 = 1 (E) state, at about 1396 cm−1. In these bands the resonance is localized on rotational levels with specific J and K values. As a consequence, a few transitions of the perpendicular bands involving the interacting levels could be identified in the spectra. A simultaneous fit of the transitions assigned to the dyads has been performed and the parameters of the excited states have been determined, including the high order Coriolis interaction coefficient . The anharmonic constants x11, x22, x33 of all the studied isotopologues of FClO3, x46 of F35Cl16O3, x46 + g46 of F37Cl16O3 and x16 of F37Cl18O3, have been derived. 相似文献
11.
由原子在点阵中扩散的反应率过程理论,在最近邻近似下,计算了AB合金的长程有序化动力学及长程序为零时的短程有序化动力学。所得结果与前人的实验结论及计算结果相比定性地符合,定量地接近。长程有序化动力学的计算表明,有序化过程存在有孕育期,有c-曲线形式的转变曲线,s近似与exp{-αt2}正比,算得的平衡有序度与前人计算结果相近。长程序为零时的短程有序化动力学的计算表明,σ近似与exp{-βt}正比,此时有序化速率甚快,以致在最快的淬火速率下,样品中也必然存在有一定的短程序,所得的平衡短程序值也符合前人的计算结果。本文是作为继续计算短程有序化动力学的准备及基础。 相似文献
12.
13.
14.
本文通过电阻测量研究了淬火和退火温度对AuCu合金有序化过程的影响,结果表明:1.AuCu合金的有序化过程可分为两个阶段:1)局部有序或有序相成核阶段,电阻上升;2)有序相(或畴)长大阶段,电阻下降。2.淬火后低温退火时,AuCu有序化主要是通过过饱和的淬入空位在金属中的移动而实现的。有序化的速度正比于淬入空位的浓度和移动率。3.通过有序化速度随淬火温度和退火温度的变化,测得AuCu中空位的形成能Ef和移动激活能Em相应为0.95eV和0.81eV。4.在等温退 相似文献
15.
The crystallization of the amorphous Cu60Zr40 alloy has been studied by differential scanning calorimetry (DSC), scanning Auger microprobe (SAM) and transmission electron microscopy (TEM). The DSC trace showed that the sample exhibited a glass transition at 750 K and a strong exothermic effect beginning from 782 K. An enrichment of the element Zr and significant oxygen contamination in a zone near the surface to a depth of about 10 nm were revealed by SAM in the analysis of surface competition and depth profiles of the Cu60Zr40 sample. Also, the change of concentration ratio of Ca to Zr in amorphous matrix at the clean Cu60Zr40 surface as a function of annealing temperature was examined in detail, and it was found that the concentration of Zr at the surface is slightly higher than that in the bulk until 780K and that the concentration ratio of Cu to Zr in matrix has an abrupt increase in the temperature range of 780-800K. The observations by high resolution TEM revealed the appearance of cluster-like regions of approximately 1.5-2.0 nm in size just before crystallization and they distributed randomly throughout the sample. This phenomenon is analogous to the results obtained using field ion microscopy (FIM) by the present authors. The microstructural changes of the sample daring heating show the gradual crystallization of the amorphous matrix. 相似文献
16.
以57Fe作为探针,用穆斯堡尔效应研究YBa2Cu3O7-δ的磁有序与超导电性的关系。实验结果可以用非声子超导机制进行定性解释。
关键词: 相似文献
17.
用射频/直流磁控溅射法制备了CeO2/Nb2O5双层氧敏薄膜,利用X射线光电子能谱(XPS),描述并解释了单层CeO2薄膜中氧随温度变化的动力学行为,以及CeO2/Nb2O5薄膜界面对氧敏特性的影响.通过对Ce3d XPS谱的高斯拟合,计算了Ce3+浓度并给出了判定Ce4+还原的标志.结果表明,界面效应可以提高CeO2/Nb2O5薄膜中Ce4+的还原能力,使之远远高于单层CeO2薄膜,这对薄膜的氧敏特性是极为有利的.
关键词: 相似文献
18.
19.
利用X射线衍射仪对非晶态Mg70Zn30合金的结构进行了研究,获得了强度曲线、结构因子、双体分布函数和原子间最近邻距离.结果表明,Mg70Zn30合金在小Q区间存在强烈的预峰现象.根据预峰的特性,提出了Mg70Zn30熔体的结构模型,即Mg原子位于中心,8个Zn原子位于顶角所形成的简单立方结构模型.该模型以共享顶点的方式相连接,能够满足预峰对Mg—Mg原子间距离的要求.Mg<
关键词:
非晶态
70Zn30合金')" href="#">Mg70Zn30合金
结构因子
预峰 相似文献