排序方式: 共有38条查询结果,搜索用时 328 毫秒
31.
32.
33.
34.
This paper reports that the YBa2Cu3-xZnxO7-δ (x = 0-0.4) samples are researched by means of x-ray diffraction, calculations of binding energy, the positron experiments and variations of oxygen content. The results of simulated calculations, positron experiments and variations of oxygen content support the existence of cluster effect. Moreover, it is concluded that the cluster effect is an important factor on suppression of high-Tc cuprate superconductivity and the Tc does not depend on the density of valence electron directly. 相似文献
35.
36.
37.
The optical limiting performances of few-layer transitional metal dichalcogenides (TMDs) nanosheets in the VB group(VS2,VSe2,Nb S2,Nb Se2,Ta S2,and Ta Se2) were systematically investigated for the first time,to the best of our knowledge.It was found that these TMDs nanosheets showed a normalized transmittance in the range of 20%–40%at the input energy of 1.28 GW/cm2.Ultralow initial threshold FS(0.05–0.10 J/c... 相似文献
38.
光催化转化CO2为碳氢燃料,分解水产氢,选择性有机合成,还原N2为NH3,降解毒害的有机污染物等对解决能源环境问题有重要意义。早在1972年,研究者利用TiO2通过光催化实现了全面分解水产氢和产氧。由于低的可见光利用率,严重的载流子复合和过高的水氧化能垒导致光催化全面水分解的效率极低。由于氢相对于氧更具有经济价值,因此牺牲剂辅助的光催化产氢被大量研究。由于牺牲剂可以快速的消耗光生空穴,有效降低了氧化端的能垒,光催化产氢的效率相比于光催化水分解的效率提高了3–4个量级。然而,牺牲剂的使用不仅导致了光生空穴的浪费,成本的提高,还导致了潜在的环境问题。近些年,研究者通过将光催化还原反应和光催化氧化反应结合在一起实现了电子空穴的全面利用,并改进了氧化和还原的效率。同时,电子空穴的全面利用也有效的促进了电荷的分离并提高了催化剂的稳定性。然而,由于全面氧化还原的设计难度大,反应过程复杂,因此光催化全面氧化还原的机理尚不够明确,仍然需要大量的探索。在这篇综述中,首先从光捕获、光激发电荷分离、氧化还原反应的热力学和... 相似文献