排序方式: 共有33条查询结果,搜索用时 15 毫秒
11.
An analytic expression for the ionization amplitude of hydrogen by electron impact is found to contain a polyno-mial by an optimal truncation in an asymptotic series and a convergent series. The ionization amplitude, i.e., the transition matrix element on the energy shell, is decomposed into two parts: the structure-scattering factor and correlation factor, based on an approximation of the projectile plane wave in coplanar asymmetric geometries.The contribution of these factors to the triple differential cross section is evaluated using the method of optional truncation of asymptotic and convergent series. 相似文献
12.
A radiation-temperature coupling model of the optical fiber attenuation spectrum in the Ge/P co-doped fiber 下载免费PDF全文
A radiation-temperature coupling model of optical fiber attenuation spectrum has been developed. The spectrum in Ge/P co-doped fiber ranging from 800 nm-1600 nm at different temperatures and doses was measured and decomposed according to the configurational coordinate model based on which the power-law model was employed to predict the intensity of the color center absorption band at different doses. And the fiber loss in space was predicted by the model. This work will benefit the application of fibers in a complicated radiation environment. 相似文献
13.
14.
周长-面积关系及分形维数的计算机模拟 总被引:1,自引:0,他引:1
本文利用分形理论中周长-面积关系的基本概念,对初始形状为三角形的不同大小的Koch曲线围成的岛,模拟了不同条件下,测量D值的变化规律,并进一步指出应用这一关系所应满足的条件及实际测量中有限层次的影响,探讨了所需条件在实际应用中的物理意义。 相似文献
15.
16.
采用一步法分别制备了Sn类CH3NH3Sn I3和Pb类CH3NH3Pb I3钙钛矿太阳电池薄膜材料,并对其表面形貌、微观结构、吸收光谱和电池器件性能进行了表征和测试。研究结果表明:Sn类钙钛矿材料的吸收光谱相对于Pb类钙钛矿材料发生了明显的红移,吸收截止波长从800 nm上升到950 nm左右,光学带隙由1.45 e V降低至1.21 e V左右;Sn类钙钛矿材料的光谱吸收范围明显扩大,但吸收强度有所降低,相应太阳电池器件的光电转换效率也明显低于Pb类钙钛矿太阳电池,分别为2.05%和6.71%。而Br的掺杂可使Sn类钙钛矿材料带隙变宽,吸收光子能量增大,电池器件的开路电压也相应提高。当Br含量由0增加至完全替代I时,Sn类钙钛矿材料逐渐由黑褐色转变为黄色,光学带隙增大至1.95 e V,但吸收截止波长由950 nm降低至650nm。值得提及的是当Br含量为0.5时,电池器件的光电转换效率可由最初的2.05%提升至2.94%。 相似文献
17.
利用等离子体增强化学气相淀积技术,在绝缘氮化硅(SiNx)衬底上制备超薄非晶硅(aSi:H)薄膜,通过超短脉冲激光辐照与准静态常规热退火技术处理,制备出高密度、均匀纳米硅(ncSi)量子点.使用原子力显微镜对处理前后样品的表面形貌进行了研究,发现激光辐照能量密度增加的同时,所形成的ncSi尺寸也随之增加.在合适的能量密度范围内,可以得到面密度大于10.11cm^2、尺寸分布标准偏差小于20%的10 nm ncSi量子点薄膜,表明所制备的ncSi量子点具有较好的均匀性及较高的面密度.同时,对ncS i量子点
关键词:
纳米硅
激光诱导
尺寸分布 相似文献
18.
20.