严重段塞流现象与立管顶部节流的瞬态模拟

在对严重段塞流现象实验研究的基础上,本文采用OLGA软件建立了实验系统的瞬态模型,对水平段长度为114 m,下倾段长度为133 m,立管高度为15.3 m,内径为50.8 mm的集输-立管系统中的严重段塞流现象进行了数值研究,给出了相应流型图,并将立管底部压力、立管顶部持液率、段塞周期等严重段塞流特性参数的模拟结果与实验结果进行了对比;本文还对控制严重段塞流现象的立管顶部节流法进行了模拟研究,并与实验结果进行了对比。研究发现,本文的瞬态模型能够较好地模拟出实验中发现的四类流型,但对严重段塞流详细特性参数的模拟不够准确,对顶部节流的模拟与实验结果相差较大,对顶部节流法消除严重段塞流的机理仍需进一步研究。     

Van der Pauw Hall Measurement on Intended Doped ZnO Films for p-Type Conductivity

A Van der Pauw Hall measurement is performed on the intended doped ZnO films （Na doped ZnO） grown by using the molecular beam epitaxial method. All as-grown samples show n-type conductivity, whereas the annealed samples （annealing temperature 900℃） show ambiguous carrier conductivity type （n- and p-type） in the automatic Van der Pauw Hall measurement. A similar result has been observed in Li doped ZnO and in as-doped ZnO films by other groups before. However, by tracing the Hall voltage in the Van der Pauw Hall measurement, it is found that this alternative appearance of both n- and p-type conductivity is not intrinsic behavior of the intended doped ZnO films, but is due to the persistent photoconductivity effect in ZnO. The persistent photoconductivity effect would strongly affect the accurate determination of the carrier conductivity type of a highly resistive intended doped ZnO sample.     

微通道中气体流动的格子Boltzmann数值模拟

采用可压缩格子Boltzmann模型及非平衡外推边界条件,数值模拟微通道中的气体在滑移区域(Kn≤0.1)内的流动,计算结果包括出口速度剖面、通道中心压力分布以及质量流率等,与理论结果及其他实验结果符合得很好.还模拟了180°弯曲通道中的气体流动.结果表明,滑移速度的存在抑制了边界层的分离,因此在弯曲处不存在漩涡.计算结果还表明,弯道的存在显著影响了气体的质量流率.     

基于Vega的红外图像仿真

介绍了红外成像仿真的基本理论,讨论了利用Vega传感器模块将输入的可见目标图像生成红外图像的技术。该技术使用Creator软件进行三维几何建模和纹理映射,使用TMM软件进行红外材质建模;然后,用Mat软件进行大气衰减的计算;最后,用SensorWorks软件进行传感器特性建模,通过光电转换生成红外图像。以阿帕奇AH6直升机为例进行了红外图像仿真,结果表明,利用Vega传感器模块进行传感器建模,建模效果较好,成本低,易于工程实现。     

300～1100nm多波段成像光学系统设计及杂光分析

设计了一套300～1100nm多波段光学系统,该系统能对目标的近紫外、可见光和近红外3个波段同时成像,可满足目标多波段信息探测的要求。由于在光学系统中镜筒内壁反射和棱镜表面反射会产生杂光和鬼像,因此,利用Light—Tools软件对此系统的杂光和鬼像进行了模拟分析。模拟结果表明,视场之外11．7—18．3°和-11．7～-18．3°的入射光线被胶合棱镜上下表面反射后,会聚焦到3个探测器靶面范围内,形成鬼像;6．2°-9．8°和一6．2°--9．8°的入射光线被镜筒反射后会在3个探测器上形成杂光。利用设计的多波段光学系统进行了相关实验,结果证明了模拟分析的正确性,表明此分析能用于指导多波段光学系统的设计和研制。提出了减少杂光和鬼像的相应措施,实验结果验证了提出的措施能够减少杂光及消除鬼像,提高系统成像质量。     

Perturbation characteristics of ambient sea noise caused by submerged objects

The perturbation characteristics of ambient sea noise field caused by scattering of submerged objects are discussed theoretically. Based on the sea noise source model with Gaussian-correlation amplitude, and applying the integral expressions for arbitrary source distribution and the spherical wave expression of Green function for a monopole in half-infinite space, the expressions of direct-arrival noise fields, scattering fields and total noise fields of a rigid spherical object under the irradiation of monopole and dipole sources, as well as the covariance among those noise fields at two receiving points are obtained. The numerical results of scattering directional patterns of rigid spherical objects and the visibility are given. It is shown that the total noise field is affected by not only the impedance characteristics of the object, the direction of receiver, but also the correlation between surface sources, and the interference between direct-arrival and scattering fields greatly. The results show that the sound visibility of a rigid spherical object is about 4-5 dB in near range and the scattering directivity characteristics of a rigid spherical object under the irradiation of surface sources are different from those of plane wave incidence.     

Phase Dependence of Fluorescence Spectrum of a Two-Level Atom in a Trichromatic Field

We examine the phase-dependent effects in resonance fluorescence of a two-level atom driven by a trichromatic modulated field. It is shown that the fluorescence spectrum depends crucially on the sum of relative phases of the sideband components compared to the central component, not simply on the respective phases. The appearance or disappearance of the central peak and the selective elimination of the sideband peaks are achieved simply by varying the sum phase. Once the sum phase is fixed, the spectrum keeps its features unchanged regardless of the respective relative phases.     

一种新型桥路型HTSFCL的实验研究

在研究一种新型桥路型高温超导限流器的限流原理的基础上，研制开发了一台三相600V、故障电流峰值100A的实验室样机．本文介绍了该限流器的功率电路、控制器、低温容器和高温超导磁体等部分的结构特点和功能．在三相系统中进行了各种短路故障限流实验，结果表明该限流器有较强的限流能力和重合闸能力，说明新型高温超导限流器的研究对改善电网动态性能和提高电网电能质量有十分重要的意义．     

RIBLL终端LASCAR闪烁体阵列探测器研制进展

介绍了RIBLL终端LASCAR闪烁体阵列探测器的工作原理和结构特点. 描述了为满足放射性核束实验的要求而对阵列所作的重要改进. 给出了LASCAR构型优化改造的工作设想和实施步骤. The principles and structure characteristics of LASCAR scintillator array detector at RIBLL terminal are described. Special emphases are laid upon the latest progress for the development of LASCAR array detector to meet the requirements of the RIB experiments. The working plan and steps for optimizing configuration of the LASCAR multi unit neutron scintillator array detector are also presented.     

第二配体对Sm(DBM)3掺杂的PMMA样品发光的影响

分别使用phen（1,10-邻菲咯啉）、TOPO（三正辛基氧化磷）、TPPO（三苯基氧化磷）作为第二配体与Sm（DBM）3（DBM：二苯甲酰甲烷）相互作用,合成了相应的配合物,然后分别将其掺入MMA中,进行聚合得到了固体样品。测量了不同第二配体样品及无第二配体样品的激发和发射光谱,对谱峰做了指认。发射谱中主要发射峰均为Sm^3＋的特征发射,有机配体的发光带很弱,说明从有机配体到稀土发光中心的能量传递非常有效。监测Sm^3＋离子644nm发射峰（^4G5/2→^6H9/2）测量了样品的激发光谱。结果显示,第二配体的加入改变了有机配体的能级结构,激发边出现明显的移动,同时紫外区的激发效率发生了变化,对发光产生了显著的影响。还测量了上述样品中Sm^3＋的^4G5/2能级的发光衰减曲线,拟合出该能级的跃迁寿命,针对不同第二配体的情况进行了比较分析。实验结果表明,第二配体的共轭性和化学键匹配对发光强度影响很大,在我们的结果中,第二配体为TPPO时发光效率最高。