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Double-walled carbon nanotubes are needed in a pure, highly crystalline form before features such as their electronic properties, thermal transport and mechanical behaviour can be investigated. Here we fabricate a paper-like material that consists of hexagonally packed bundles of clean, coaxial carbon nanotubes whose double walls vary little in diameter; it is prepared in high yields using chemical-vapour deposition with a conditioning catalyst and two-step purification. Our results will enable investigation of the physical properties of double-walled carbon nanotubes, which are predicted to be superior to those of both their single- and multiwalled relatives. 相似文献
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Thin films. Wrinkling of an elastic sheet under tension 总被引:1,自引:0,他引:1
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Feringa BL 《Nature》2000,408(6809):151, 153-151, 154
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It is generally accepted that magnetic order in an insulator requires the cation to have partially filled shells of d or f electrons. Here we show that thin films of hafnium dioxide (HfO2), an insulating oxide better known as a dielectric layer for nanoscale electronic devices, can be ferromagnetic even without doping. This discovery challenges our understanding of magnetism in insulators, because neither Hf4+ nor O2- are magnetic ions and the d and f shells of the Hf4+ ion are either empty or full. 相似文献
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利用溶胶-凝胶法(Sol-Gel)制备BaTiO3薄膜,介绍了Pt/Ti/SiO2/Si(100)衬底及BaTiO3薄膜的制备工艺过程,对薄膜的表面形貌进行了观察分析,同时对其介电与频率关系进行了测试.结论显示,经900℃、120min退火处理的BaTiO3薄膜的结晶性能优良,并具有一定的电学性能. 相似文献
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SUN Jingzhi YANG Xinguo WANG Mang 《科学通报(英文版)》2005,50(19):2157-2160
Porphyrin-perylene dyad molecular arrays are impor-tant building blocks for mimic photosynthetic systems and molecular opto-electronics such as molecular wires, logic gates and molecular switches. In recent years, Wasielewski’s group[1―3] and Bocian and Lindsey’s group[4―7] have systematically investigated the electronic structure, the mechanism of transient photoinduced charge and/or energy transfer in a few representative porphyrin- perylene arrays, the acquired results threw light on th… 相似文献
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随着铸造支撑辊在连铸连轧生产工艺中的广泛应用,轧钢厂对支撑辊的要求越来越高,在选择轧辊的时候要充分考虑轧辊的材质、制造工艺、热处理以及实际应用情况等要素,同时对复合铸钢支撑辊辊身深层剥落的原因进行了分析。 相似文献
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使用低介电常数基板和高电导率、高抗电迁移的金属Cu进行布线,可以提高高密度电子封装的传输速度和可靠性。采用乙酰丙酮铜作为前驱体,在常压下利用化学气相沉积技术对玻璃陶瓷基板进行Cu薄膜金属化。利用热重分析、X射线衍射和扫描电子显微镜等技术对前驱体、Cu薄膜进行分析观察。结果表明:影响Cu导体的电阻的主要因素是沉积温度。在温度为290~310℃,N2气流量为200~350mL/min和H2气流量为450~600mL/min的条件下,获得了致密的Cu薄膜,Cu导体方块电阻为25mΩ。 相似文献