元素掺杂对VH2解氢性能的影响

采用密度泛函理论（DFT）的第一性原理的平面波超软赝势方法,研究了Zr、Cu、Zn掺杂对VH2的电子结构和解氢性能的影响．计算结果显示Zr掺杂VH2后晶体模型的负合金形成热增加和费米能级目处电子浓度N（Ef）的减少,体系结构稳定性增强;V—H之间重叠集居数和电子密度计算也显示V-H之间相互作用增强;表明在VH2中掺杂Zr以后吸放氢最大容量增加,但解氢能力减弱．而Cu或Zn掺杂VH2以后晶体模型的负合金形成热减少和费米能级Ef处电子浓度N（Ef）增加,体系结构稳定性减弱;V-H之间重叠集居数和电子密度计算也显示V-H之间相互作用减弱;表明在VH2中掺杂Cu或Zn以后吸放氢最大容量降低,但解氢能力增强．与实验结论相符．同时Mulliken集居数计算结果还显示V-d轨道MuUiken集居数与掺杂有关,掺杂Zr以后V—d轨道Mulliken集居数减少;掺杂Cu或Zn以后V—d轨道Mulliken集居数增加．     

LaGaO3基固体氧化物燃料电池阳极材料Ce1-xTmxO2-δ（Tm=Cu,Mn,Fe）研究

以研究与Sr,Mg掺杂LaGaO3(LSGM)电解质匹配的阳极材料为出发点,系统研究了Ce1-xTmxO2-δ(Tm=Cu,Mn,Fe)固溶体的晶体结构、热化学稳定性、电化学性能和单电池发电实验。柠檬酸法合成的Ce1-xTmxO2-δ化合物在x<0.2时均为单相材料,与LSGM电解质有良好的热化学相容性。采用交流阻抗法研究了阳极材料的电化学性能,金属元素掺杂可以显著地改善CeO2电化学性能,Fe元素掺杂阳极材料极化电阻最小,随着元素掺杂量的增加以及氢气增湿,极化电阻减小。采用电解质支撑结构单电池进行发电实验,在800℃时,以Ce0.8Fe0.2O2-δ作为阳极的单电池最高功率密度可达98 mW.cm-2,表明该材料作为IT-SOFC的阳极材料具有一定的可行性,有望成为适合LSGM电解质的阳极材料。     

合金化对VH2解氢性能的影响

采用密度泛函理论(DFT)的第一性原理的平面波超软赝势方法, 研究了C, Si, Ge, Sn, Pb合金化对VH₂的电子结构和解氢性能的影响. 计算结果显示C, Si, Ge, Sn, Pb合金化VH₂后晶体模型的负合金形成热减少, 费米能级E_f处的电子浓度N(E_f)增加, 表明体系结构稳定性减弱, 解氢能力增强|V-H之间重叠集居数和电子密度计算也表明V-H之间相互作用减弱, 解氢能力增强|同时Mulliken集居数计算结果还显示掺杂以后解氢能力增强与V-d轨道Mulliken集居数减少, V-s轨道Mulliken集居数增加有关.     

A theoretical study of the influence of dopants on the dehydrogenation properties of VH_2

Using the plane wave ultrasoft pseudopotential method based on the first-principles density functional theory(DFT),the influence on the electronic structure and dehydrogenation properties of VH2 doped with Zr,Cu and Zn has been studied.The results show that the negative heat of formation increases and the valence electron number at the Fermi level EF,N(EF) decreases in the Zr-doped model,indicating the higher stability of VH2 after Zr alloying.On the other hand,the negative heat of formation of VH2 decrease...     

Theoretical and experimental study on rare-eath element-doped silicon single-mode fiber laser with two different structures of resonators

Abstract: Laser resonator is very important in the study and fabrication of lasers. The work conditions and work parameters of rare-earth element-doped optical fiber lasers with two different structures of laser resonators, i. e., the fiber ring resonator and Fabry-Perot resonator are studied. The fineness, laser resonant conditions, laser oscillation conditions and threshold inversion of these two different cavity are deduced. A series of experiments are also given. The result is very valuable to evaluate the output of optical fiber laser and can be a foundation of device fabrication. The Nd~(3 )-doped silica single-mode fiber laser pumped by Ar~ laser with a low threshold of 1.02 mW and a maximum output of more than 1 mW are presented in this paper.