微型计算机在微弱光谱测试系统中的应用

本文报道了在我们研制的微弱光谱测试系统中微计算机的应用,介绍了数据采集、双机间的DMA传送数据、二维光栅扫描控制、应用微机改善信噪比、应用软件和图形显示等问题。着重讨论如何通过我们所做的研制工作,使性能较低的EG3003微计算机达到OMA系统所要求的水平。     

混合纤芯光子晶体光纤超平坦色散的研究

利用平面波展开法,系统地研究了一种具有混合纤芯结构的光子晶体光纤的色散特性. 数值计算结果表明,通过优化结构参量,这种新型结构的光子晶体光纤在通信窗口1.55 μm 附近可以获得带宽超过800 nm的超平坦色散区域（色散曲线的变化范围不超过 ±0.6 ps·km－1·nm－1）.     

光子晶体光纤非线性系数与其结构参量及光波长的关系

推导计算了全内反射型光子晶体光纤的非线性系数与其两个几何结构参量:包层空气孔半径和空气孔间距之间的关系,给出了输入光波长为1550 nm处,非线性系数与这两个结构参量之间的关系曲线并对其进行了分析.给出了全内反射型光子晶体光纤的非线性系数随输入光波长变化的曲线,分析了短波处高非线性系数产生的原因并指出这一特性的应用潜力.     

串列加速器头部电极改进方案

通过改变头部电极的局部形状来改善头部电场, 运用Poisson程序计算几种可能形状下表面电场的分布, 并以此给出最佳的改进方案.     

Lu2Si2O7：Ce晶体的闪烁性能

用提拉法生长了Lu2Si2O7：Ce晶体，对该晶体的闪烁性能进行了研究。透射光谱表明，Lu2Si2O7：Ce晶体的吸收边比Lu2SiO5：Ce晶体向短波方向移动了25nm，使透光范围进一步拓宽。X射线发射光谱和UV激发发射光谱均具有典型的双峰特征，主峰在378nm。UV激发发射谱具有温度效应，即375K以上时，发光效率迅速降低；425K以上时，发光主峰位明显红移。衰减曲线符合单指数式衰减规律，常温下经UV激发后的衰减时间约为34ns。从曲线形态看，375K以下的衰减谱与室温下的几乎完全相同，拟合的结果在32．8～34ns之间；衰减时间的温度效应从375K开始显现，即随温度的升高，衰减时间有加速变短的趋势，到500K时缩短为6．72ns。热释光谱在488，553K处有两个热释光峰，但室温附近几乎观察不到热释光峰。     

The effect of glottal angle on intraglottal pressure

Intraglottal pressure distributions depend upon glottal shape, size, and diameter. This study reports the effects of varying glottal angle on intraglottal and transglottal pressures using a three-dimensional Plexiglas model with a glottis having nine symmetric glottal angles and a constant minimal glottal diameter of 0.06 cm. The empirical data were supported by computational results using FLUENT. The results suggested that (1) the greater the convergent glottal angle, the greater outward driving forces (higher intraglottal pressures) on the vocal folds; (2) flow resistance was greatest for the uniform glottis, and least for the 10 degrees divergent glottis; (3) the greatest negative pressure in the glottis and therefore the greatest pressure recovery for diverging glottal shapes occurred for an angle of 10 degrees; (4) the smaller the convergent angle, the greater the flow resistance; (5) FLUENT was highly accurate in predicting the empirical pressures of this model; (6) flow separation locations (given by FLUENT) for the divergent glottis moved upstream for larger flows and larger glottal angles. The results suggest that phonatory efficiency related to aerodynamics may be enhanced with vocal fold oscillations that include large convergent angles during glottal opening and small (5 degrees - 10 degrees) divergent angles during glottal closing.     

Strategy of improving the stability and detonation performance for energetic material by introducing the boron atoms

A novel stable energetic compound (E)‐1,2‐diamino‐1,2‐dinitrodiboron (DANB) was theoretically designed based on the structure of 1,1‐diamino‐2,2‐dinitroethene (FOX‐7). Atomization method in combination with Hess' law was used to predict the heat of formation. The detonation velocity (D) and detonation pressure (P) of DANB were approximatively estimated by using Kamlet–Jacobs equations. As a result, DANB has huge heat of formation (2013.5 kJ/mol) and specific enthalpy of combustion (?26.4 kJ/g). Furthermore, DANB possesses high crystal density (1.85 g/cm³) and heat of detonation (5476.0 cal/g), which lead to surprising detonation performance (D = 10.72 km/s, P = 51.9 GPa) that is greater than those of FOX‐7 (D = 8.63 km/s, P = 34.0 GPa) and CL‐20 (D = 9.62 km/s, P = 44.1 GPa). More importantly, DANB is very stable because its bond dissociation energy of the weakest bond (BDE = 357.8 kJ/mol) is larger than those of the most common explosives, such as FOX‐7 (BDE = 200.4 kJ/mol), CL‐20(BDE = 209.2 kJ/mol), HMX(BDE = 165.7 kJ/mol), and RDX (BDE = 161.4 kJ/mol). Therefore, our results show that DANB is a promising candidate for stable and powerful energetic material.     

含石墨烯二维金属结构中的自发辐射研究

研究原子在金属结构中的自发辐射时引入单层石墨烯薄膜,利用石墨烯特殊的光电特性来调控原子的自发辐射率.推导了局态密度与自发辐射率的格林函数表示形式,并结合频域有限差分方法进行了数值模拟.分析结果表明:随着化学势的增大,自发辐射波峰出现蓝移现象,且自发辐射率波峰得到增强,理论上实现了原子自发辐射率峰值位置与幅度的调制.研究结果可以为新型纳米器件及光电子设备的制造和优化提供参考.