排序方式: 共有28条查询结果,搜索用时 9 毫秒
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本文利用ICP光谱法测定了11个古青铜器中的主要元素Cu、Sn、Pb和微量元素As、Ni、Fe、Ag的含量,结果完全满足考古研究的要求,为考古研究提供了科学的依据。 相似文献
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用电子探针对广西金牙微细粒金矿金赋存状态的研究 总被引:1,自引:0,他引:1
微细粒金赋存状态的研究,对搞清此类金矿的成因,指导这类金矿的勘探、开采和选冶有着重要意义,本文报道了用电子探针对广西金牙微细粒金矿的矿石进行了观察分析,首次在金牙金矿床含金矿化物表面发现了含铂汞金矿、汞金矿、铂金太航自然金,并确定出它们的尺度。 相似文献
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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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以单分散SiO2 胶态晶体球形成的三维有序结构为模板 ,利用胶体晶模板技术合成了三维长程有序的二氧化锰大孔材料 .通过X射线粉末衍射 (XRD)和扫描电子显微镜 (SEM)对产物进行了表征 .其中XRD数据显示所得产物为纯四方相二氧化锰 .SEM结果表明 ,所合成的二氧化锰大孔材料孔大小均匀 ,空间排列高度有序 ,很好地复制了SiO2 胶态晶体球的自组装方式 .此外 ,对三维有序二氧化锰大孔材料的合成过程进行了分析 ,研究了前体填充次数对产物孔结构的完整性和有序性的影响 ,还发现产物孔径的收缩存在异常现象 . 相似文献
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The GaxIn1-xP/GaAs heterostructures with different x values have been investigated by photoluminescence (PL), energy dispersive spectrum (EDS), and transmission electron microscopy (TEM). Experimental results suggested that the composition of epitaxial layers evidently affected the microstructure of the heterostructures. When x value was close to 0.5, the defects in the epitaxial layer decreased, and the lattice match between film and sub-strate approached optimum, Meanwhile, the heteroatructure provided a high luminescence efficiency. 相似文献
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同样经过空气中900℃至室温淬火,纯YBa2CU3O7-x(YBCO)不超导,而适量掺WO3的YBCO却可在88K以上显示超导电性,更为奇妙的是,W并没有进入YBCO晶格.为弄清后者超导电性恢复的原因,本文对经过以上条件淬火的纯YBCO及掺3wt%WO3的试样进行了一系列研究,并对比研究了相同条件下烧结但在氧气氛中慢冷却的样品.所有结果均表明,淬火过程中掺杂样品冷却较慢很可能是使之恢复超导电性的主要原因.本工作的重要意义在于从非稳态导热的角度探讨了适当掺杂的淬火YBCO超导电性恢复的原因,并可能对改进相应材料超导薄膜的制备工艺有所启迪. 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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碳内米管的提纯,填充及用作场发射电子源 总被引:3,自引:0,他引:3
碳纳米管是90年代发现的一种新型材料,具有潜在的应用价值。文章介绍了怎样提纯碳纳米管,如何在碳纳米管内填充材料,以及用碳纳米管作发射电子源等研究工作的进展。 相似文献