| 查看: 391 | 回复: 0 | ||
超级老快木虫之王 (文学泰斗)
|
[求助]
英译汉，一段文字！
|
| These microstructural changes may enhance the photoluminescence intensity of dopant ions by increasing the oscillating strengths of the optical transitions and by decreasing internal reflections on crystallite surfaces. Furthermore, compared with samples lacking Li+ ions,the number of dopant ions in the vicinity of crystallite surfaces is smaller in the Li+ co-doped samples, and consequently, the emission intensity should be less degraded by surface ligands. In the present case, the structural parameters of GdVO4: Er3+/Yb3+ powders do not follow the a fore-mentioned trend when the Li+ co-doping concentration increases,as detailed in Table1. The crystallite size of the powder is almost doubled when powders are co-doped with 5mol% of Li+ ions (91nm instead of 56nm), and the size does not change with a further increase in Li+ concentration. Microstrain exhibits the same behavior as crystallite size. Its value increases from approximately 0.06% in the powder with no Li+ ions to about 0.29% in the powder co-doped with 5mol% of Li+ ions, and the value stays approximately the same at higher co-doping levels.Conversely,other structural parameters, such as the unit cell volume and lattice parameters, constantly decrease with an increase in the Li+ co-doping concentration. The different behavior for emission intensities, which vary with respect to the Li+ co-doping concentration, is observed with DC and UC luminescence. In UC luminescence, the intensity of emission is four times greater in the powder co-doped with 5mol% of Li+ ions than in then on-co-doped powder.However, the enhancement is reduced in samples with higher Li+ ion concentrations. A probable explanation of this phenomenon is that at high Li+ co-doping concentration there is afraction of Li+ ions sufficiently large to induce the fast energy transfer from the host to the Er3+ ions and hence to create an increase in the hole concentration leading to a decrease in competitive absorption. |
回复此楼» 猜你喜欢
面上的水很深
已经有8人回复
-
生命口C13面上会评时间
已经有11人回复
-
内心匮乏
已经有16人回复
-
生命口面上会评结束了吗大家有知道结果吗？现在还没有结果正常不？
已经有9人回复
-
投英文期刊如何查重
已经有6人回复
-
不要再数国自然申请书的 filecode 的分隔符个数了
已经有21人回复
-
伯胺上甲基求助
已经有7人回复
-
跨出版社商投稿
已经有5人回复
-
5个%2F，非固定段22个字母
已经有7人回复
-
生生命学部会评
已经有4人回复