引入Sb降低CZTS硒化温度的研究

采取直接在Cu_2ZnSnS_4(CZTS)驱体溶液中溶解锑基化合物的方法于CZTS中引入Sb,探究了不同浓度Sb的引入对于CZTS薄膜太阳能电池的影响.研究结果表明Sb的引入能够显著降低CZTS的硒化温度至470℃.同时XRD和SEM表征测试结果表明随着Sb引入浓度的增加,低温下制备的CZTS薄膜的结晶性得到了逐渐的增强.EQE测试结果表明Sb引入之后CZTS薄膜太阳能电池的光响应也得到了提升,最终能够大幅提升CZTS薄膜太阳能电池的各项光伏性能参数,在4%(物质的量分数) Sb的引入量时得到了7.72%的效率.     

利用马赫-增德尔干涉仪改善光纤激光器输出激光性能的研究

本文设计了马赫-曾德尔干涉仪(MZI)在实验上改善1.5μm光纤激光器的输出性能,研究了MZI分束镜的反射率以及锁定MZI透过率对抑制激光输出噪声的影响。在MZI运转于最佳状态时,1.5μm光纤激光器的功率稳定性由±0.20%提升至±0.09%,激光的强度噪声在10 kHz^35 kHz分析频率范围内得到了抑制,在分析频率为15 kHz处,强度噪声降低了约8 dB,为制备1.5μm非经典光场提供了优质激光光源。     

LD端面泵浦全固态连续单纵模3微米激光器的理论研究

理论研究了LD端面泵浦全固态连续单纵模3μm激光器的输出特性。基于对Er:YAG激光器的能量过程的分析,建立了考虑晶体热效应影响的速率方程模型,讨论了晶体控温温度、掺杂浓度、晶体长度、泵浦-振荡激光模式匹配比率、输出镜透射率、单向器插入损耗等参数对连续单纵模3μm激光输出特性的影响,为高功率连续单纵模3μm激光光源的设计和优化提供了理论依据。     

Generation of self-oscillations from a singly resonant periodically poled potassium titanyl phosphate crystal frequency doubler

We report on the generation of self-oscillations from a continuously pumped singly resonant frequency doubler based on a periodically poled potassium titanyl phosphate crystal （PPKTP）. The sustained square-wave and staircase curve of self-oscillations are obtained when the incident pump powers are below and above the threshold of subharmonic-pumped parametric oscillation （SPO）, respectively. The self-oscillations can be explained by the competition between the phase shifts induced by cascading nonlinearity and thermal effect, and the influence of fundamental nonlinear phase shift by the generation of SPO. The simulation results are in good agreement with the experiment data.     

MATLAB App Designer在法布里-珀罗干涉实验中的应用

基于法布里-珀罗(F-P)多光束干涉原理,利用MATLAB设计了基于F-P干涉实验的可视化App仿真界面,不仅可复现F-P腔长、入射波长、透镜焦距等参数对F-P干涉图样的影响及实时动态展示,还可观察周围介质折射率、F-P腔折射率与干涉图样的关系,并能进行多波长分辨率和微小波长差测量实验的演示.这些直观形象的模拟结果展示,将有助于改善多光束干涉理论及实验教学效果.     

一种新型介孔空腔二氧化硅纳米微球的制备与缓释行为

本文用十六烷基三甲基溴化铵(CTAB)作为试剂,通过软模板法合成介孔二氧化硅,利用在合成过程中,由伪莫尔转动所引起的微粒内部的大量缺陷,通过溶剂抽提,形成了具有空腔结构的介孔二氧化硅纳米微球.采用透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)、N2吸附-脱附等手段对产物的形貌和结构进行了详细的表征.并以溴甲酚绿作为目标物,通过改变压强和温度,调节溴甲酚绿进入空心SiO2微球中的不同部位,对所制备的空腔介孔二氧化硅微球进行染料的装载和释放试验.结果显示该微球腔壁具有可渗透性和缓释性,而且在负压蒸发溶剂的情况下可以得到较高的药物负载量和极大地提高缓释性能.     

A High-Power Continuous-Wave Laser-Diode End-Pumped Nd：YVO4 Laser of Single-Frequency Operation

We design and build a cw high quality and high power Nd:YV04 laser of single frequencv operation with a laser-diode dual-end-pumped geometry. The influence of the Nd^3 -doping concentration in the Nd:YVO4 crystal on the output performance of laser is theoretically and experimentally studied. With a Nd:YVO4 crystal of the Nd^3 -doping concentration 0.3 at. % and at pump power of 45 W, the output power of the single frequency laser is 18 W, and the slope efficiency is 48%.     

裂变碎片靶室在直接测量重Λ超核寿命中的应用

介绍了一种新的直接测量重超核寿命的方法. 并对其中用到的一个重要探测设备——裂变碎片靶室——在托马斯.杰斐逊国家实验室用²⁵²Cf放射源进行了测试. 该靶室的单模块时间分辨率为～163ns. 在此分辨率的基础上, 计算机模拟表明用此方法测到的超核寿命误差将在9.6ps左右.     

Influence of the randomly varying domain length of quasi—phase—matched crystals on quadrature squeezing performance

During the fabrication of quasi-phase-matched(QPM) devices,errors of periodic structure are usually inevitable.The errors result in the deviation of the actual periodic domain length from the theoretical value.In this paper,we numerically analyse the influence of errors on the quadrature squeezing performance of a degenerate optical parametric amplifier consisting of QPM devices.It is shown that errors significantly degrade the squeezing degree of the quadrature squeezed light.Due to the presence of the errors,the relative phase between the signal and the pump field for obtaining the maximum squezing depends on the propagation distance of light in the crystal and the pump power.     

Experimental measurement of radiation dose in a dedicated breast CT system

Radiation dose is an important performance indicator of a dedicated breast CT (DBCT). In this paper, the method of putting thermoluminescent dosimeters (TLD) into a breast shaped PMMA phantom to study the dose distribution in breasts was improved by using smaller TLDs and a new half-ellipsoid PMMA phantom. Then the weighted CT dose index (CTDI_w) was introduced to average glandular assessment in DBCT for the first time and two measurement modes were proposed for different sizes of breasts. The dose deviations caused by using cylindrical phantoms were simulated using the Monte Carlo method and a set of correction factors were calculated. The results of the confirmatory measurement with a cylindrical phantom (11 cm/8 cm) show that CTDI_w gives a relatively conservative overestimate of the average glandular dose comparing to the results of Monte Carlo simulation and TLDs measurement. But with better practicability and stability, the CTDI_w is suitable for dose evaluations in daily clinical practice. Both of the TLDs and CTDI_w measurements demonstrate that the radiation dose of our DBCT system is lower than conventional two-view mammography.