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采用Cundari和Stevens等推导的有效芯势对镧系金属一氢化物进行了理论计算,以探讨镧系金属元素与氢的相互作用。结果表明所有镧系金属一氢化物基态时理论上是稳定的,最稳定的是SmH,最不稳定的是DyH;键长计算结果显示,基态时镧系金属一招兵买马花物有独立王国 收缩现象发生;红外振动频率理论计算值与实验结果一致;成键轨道中,金属原子轨道的贡献主要是s轨道和d轨道:从CeH至ErH(GdH)例外)随着外层电子的增加s轨道成分逐渐增大d轨道成分逐渐减小;从TmH和LuH(包括GdH),成键轨道中金属原子轨道的贡献主要是d轨道,约为90%;约大多数镧系金属一氧化物的成键轨道中金属原子轨道f成分小于1%。 相似文献
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Effects of Substrate Temperature on Helium Content and Microstructure of Nanocrystalline Titanium Films 下载免费PDF全文
Helium-charged nanocrystalline titanium films have been deposited by HeAr magnetron co-sputtering. The effects of substrate temperature on the helium content and microstructure of the nanocrystalline titanium films have been studied. The results indicate that helium atoms with a high concentration are evenly incorporated in the deposited titanium films. When the substrate temperature increases from 60℃ to 350℃ while the other deposition'parameters are fixed, the helium content decreases gradually from 38.6 at.% to 9.2at.%, which proves that nanocrystalline Ti films have a great helium storage capacity. The 20 angle of the Bragg peak of (002) crystal planes of the He-charged Ti film shifts to a lower angle and that of (100) crystal plane is unchanged as compared with that of the pure Ti film, which indicates that the lattice parameter c increases and a keeps at the primitive value. The grain refining and helium damage result in the diffraction peak broadening. 相似文献
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The hydrogenation properties of Zr samples with and without an Ni overlayer under various plasma conditions were investigated by means of non-Rutherford backscattering and elastic recoil detection analysis.The theoretical maximum hydrogen capacity,66.7 at%,could be achieved at a hydrogen absolute pressure of-2Pa and a substrate temperature of-393K for a plasma irradiation of only 10min;this was significantly greater than that for gas hydrogenation under the same hydrogen pressure and substrate temperature.It was also found that the C and O contamination on the sample surface strongly influences the hydrogenation,and that the maximum equilibrium hydrogen content drops dramatically with the increasing total contamination.In addition,the influence of the Ni overlayer on the plasma hydrogenation is discussed. 相似文献
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采用电子束镀膜方法在Si基底上制备了Sc膜,利用XRD,SEM分析了不同镀膜工艺条件下制备的Sc膜的形貌和结构。结果表明:基底温度在350~550 ℃时,薄膜主要由单质Sc组成,而且随着基底温度的升高,膜的颗粒尺寸增大,膜也变得更加致密;基底温度提高至650 ℃时,膜全部由ScSi化合物组成,膜变成颗粒状结构。沉积速率对低温时Sc膜的形貌与结构的影响不明显,颗粒尺寸随沉积速率的增大而增大,但物相结构基本没有发生变化;而在高温650 ℃时,沉积速率对膜的形貌与结构产生了很大的影响,随着沉积速率的增大,膜表面出现了大量微裂纹,而且较低的沉积速率有利于获得衍射峰单一的膜,增大沉积速率将会导致衍射峰数量明显增加。 相似文献
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本文以N-(3-溴丙基)邻苯二甲酰亚胺合成为模板反应,研究了相转移催化无溶剂合成N-(ω-溴烷基)邻苯二甲酰亚胺的影响因素,实验证实相转移催化剂及其用量、催化剂K2CO3的用量等对反应的影响明显,得到N-(3-溴丙基)邻苯二甲酰亚胺的优化合成条件为:反应物配比为PA∶C3Br2∶K2CO3∶TBAB=1∶2∶4∶0.2,反应温度80℃,反应时间1h,N-(3-溴丙基)邻苯二甲酰亚胺产率为92%。在相同反应条件下,N-(ω-溴烷基)邻苯二甲酰亚胺的产率随α,ω-二溴烷烃的烷基链长度增加而降低。 相似文献
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采用基于量子化学基本原理的密度泛函理论,研究He原子在金属T冲的占位、能量及结构优化后材料各性质参数的变化情况,以及He原子聚集成泡的微观原因。 相似文献
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氚化物部件的主要缺点之一是它们的寿命较短,这是由于随着氚衰变,^3He在氚化物晶体中不断积累,对晶体造成损伤,破坏了氚化物的完整性,最后^3He急剧地释放。这样一来,使用金属氚化物的技术装置的工作能力就被破坏了。 相似文献