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.     

基于超高效液相色谱－四极杆－静电场轨道阱质谱的结直肠癌患者血清脂质组学研究

该研究采用超高效液相色谱－四极杆－静电场轨道阱质谱结合主成分分析（PCA）、正交偏最小二乘判别分析（OPLS－DA）对结直肠癌（CRC）患者和健康人的各50例血清样本进行脂质组学分析,通过P < 0.05和倍数变化 > 1.5或 < 0.67筛选组间差异脂质,利用受试者工作特征曲线（ROC）验证其诊断能力,为基于脂质组学的CRC筛查提供参考。结果表明,两组血清脂质谱存在明显差异,发现155种差异脂质,以磷脂酰胆碱（PC）和甘油三酯（TAG）为主,涉及磷脂酰胆碱代谢和甘油三酯代谢。筛选并鉴定9个脂质标志物,包括棕榈酰乙醇胺、棕榈酸、鞘氨醇、鞘磷脂（SM）d40∶3、SM d36∶0、TAG 58∶1、PC 34∶2、PC 36∶6、PC 38∶7,其ROC曲线面积（AUC）均大于0.80,特异性与灵敏度较高,对于CRC筛查具有较高的临床诊断价值和应用潜力。     

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.     

求解矩阵方程组A1XB1+C1XD1=E1,A2XB2+C2XD2=E2的迭代算法北大核心CSCD

应用共轭梯度方法和线性投影算子,给出迭代算法求解了线性矩阵方程组A1XB1＋C1XD1=E1,A2XB2＋C2XD2=E2在任意线性子空间上的约束解及其最佳逼近.可以证明,当矩阵方程组A1XB1＋C1XD1=E1,A2XB2＋C2XD2=E2相容时,所给迭代算法经过有限步迭代可得到矩阵方程组的约束解,极小范数解和最佳逼近.文中的数值例子证实了该算法的有效性.     

LD双端端面泵浦的高功率连续单频Nd:YVO4激光器

研制了高功率连续单频Nd：YVO4激光器。在考虑激光晶体因吸收泵浦光而产生的热透镜效应的基础上，设计了六镜环行激光谐振腔，采用两个光纤耦合输出的高功率激光二极管双端端面泵浦结构，在总泵浦功率为32．3W的情况下，得到10．4W的单频1．064μm红外输出，斜效率为43．7％，长期功率稳走性优于1％(4h)，激光器自由运转时的频率漂移小于150MHz（1min)。     

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.