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The Ta/Si multilayers on (100) Si substrate have been studied over the annealing temper-ature range from 500 to 900℃ by X-ray diffraction and cross-section transmission electron microscopy. The periodicity of the multilayers becomes worse with increasing annealing tem-perature and disappears at 750℃. At 600℃, two kinds of modulation wavelength coexist because the size of several TaSi2 grains is larger than the contracted original modulation wavelength. The films are contracted after annealing. The largest contraction, at least 40nm decreasing in thickness, occurs at 600℃. When the annealing temperature is lower than 600℃, h-TaSi2 grains grow randomly and the growth is not affected by the substrate. At temperatures higher than 750℃, h-TaSi2 grows preferentially in [001] direction parallel to [100] axis of Si substrate. The appearance of texture depends on whether the atomic diffusion is short range or long range at the corresponding annealing temperature. 相似文献
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红外光谱对碱土金属二元羧酸盐结构的研究 总被引:14,自引:2,他引:14
研究了三十种二元羧酸金属盐的红外光谱,讨论了金属离子和二元酸的种类对二元酸盐配位结构的影响。发现Mg盐、Ba盐,Sr盐为螯合配位,Ca盐,Zn盐中同时存在螯合配位和桥式配位,二元酸的种类对羧酸盐配位结构没有影响。对羧酸盐在常温和熔融后的栩位方式和结构上的差异的研究结果表明,Mg盐,Ca盐与Sr盐,Ba盐在熔融后的结构变化不同。 相似文献
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The cathode deposit produced by carbon are discharge wae studied by scanning electron microscopy, high resolution electroa microscopy, X-ray diffraction and Raman spectroscopy. The results indicate that the stacking of hexagonal carbon layer in the discharged graphite is different from the ABAB stacking sequence in graphite, and that carboy nanotube is a kind of graphite-like micro-crystal with a low-dimensional structure. 相似文献
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EFFECT OF THERMAL TREATMENTS ON THE SUPERCONDUCTIVITY OF UNDOPED AND WO3 DOPED Y-Ba-Cu-O SYSTEM 下载免费PDF全文
Undoped and WO3-doped Y-Ba-Cu-O ceramics have been slowly cooled in flowing oxygen or quenched in air from 900℃ to room temperature, after sintering at 900℃ for 3Oh in flowing oxygen. The ac susceptibility measurements show that the Tc of the quenched WO3-doped Y-Ba-Gu-O superconductor can reach 88K, while the undoped Y-Ba-Cu-O ceramic quenched in air is a non-superconductor. X-ray diffraction data show that WO3 does not enter into the YBa2Cu3O7-x lattice but forms all impurity phase. The WO3-doped YBCO specimens quenched in air consist of orthorhombic YBa2Cu3O7-x phase and an impurity phase which increases with increasing WO3 content. Raman spectra chow that oxygen contents are different for undoped and WO3-doped samples. It la suggested that suitable doping with WO3 can change the oxygen content and reduce the effect of thermal treatments on the superconductivity of Y-Ba-Cu-O system. 相似文献
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对由准稀溶液速冷凝胶化结晶方法制备的超高分子量聚乙烯(UHMWPE)膜,应用广角及小角X射线衍射进行了研究,证明所形成的膜是片晶-分子链折叠的层积状结构。片晶折叠链的分子链方向(即C轴方向)垂直于膜面,在片晶间无规排列的分子链平行膜面,具有较强的“排列”取向,片晶-无规排列链形成的大点阵间距为109(?),片晶间的无规排列链沿垂直分子链方向的统计平均间距约为4.6(?),分子链数约为4~5。这一结果在超拉伸过程中,有利于从片晶-折叠分子链到完全伸直链的转变,从而可获得超高拉伸比(λ>200)。 相似文献
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论利用2θ/a X-射线扫描方法测试分析黑漆古铜镜的表面层,结合扫描电镜分析,估算出由单一物相纳米SnO2组成的黑镜表面非金属层厚约8um,这一结论表明黑镜表面的形成与特殊的表面加工工艺有关。 相似文献