非本征型法布里-珀罗干涉仪光纤布拉格光栅应变温度传感器及其应用

介绍了光纤布拉格光栅非本征型法布里珀罗干涉仪集成复用传感器的结构、应变和温度同时监测的原理 ;观察到光纤布拉格光栅反射谱和非本征型法布里珀罗干涉仪干涉谱间的串扰 ,用 3dB带宽平均波长法减小了该串扰 ,提高了测量精度 ;将该传感器应用于三维编织复合材料的应变及温度同时监测。实验结果表明温度精度为± 1℃ ,应变精度为± 2 0 μ ,可满足实际应用的要求     

小信号脉冲抽运时掺铒光纤自发辐射的研究

自发辐射(ASE)是掺铒光纤放大器(EDFA)的重要噪声源,对于由EDFA构成的光纤激光器有重要影响。理论与实践证明,它与抽运方式紧密相关,所以研究脉冲抽运时掺铒光纤(EDF)的自发辐射有重要的学术价值。同时,脉冲抽运对于EDFA锁模激光器的研究也有一定意义。从理论和实验两方面研究了小信号脉冲抽运时,抽运脉冲宽度和幅度对于EDF的自发辐射特性的影响,得到了小信号抽运时输出ASE噪声平均值的近似解析解。研究发现,小信号脉冲抽运时输出信号的幅度与抽运脉冲的宽度成正比。这个新现象可用于脉冲宽度的全光检测。     

诺氟沙星与DNA的拉曼光谱研究

报道了诺氟沙星(NFX)及诺氟沙星胶囊内容物的FT-Raman光谱和在银胶基底上的表面增强拉曼光谱(SERS),归属了各个振动;研究了诺氟沙星与DNA的相互作用的SERS,结果表明:胶囊内容物的拉曼光谱图与对照品的拉曼光谱图的特征振动峰:C-F键的伸缩振动,C=C伸缩振动,O-C-O的对称伸缩振动峰值未发生变化,发生变化主要是分子骨架振动峰,诺氟沙星胶囊的辅料对拉曼光谱无实质影响,可建立拉曼光谱法检测诺氟沙星药物的分析方法;诺氟沙星可以在没有金属离子的存在下与DNA直接作用,与DNA相互作用的主要键合模式是插入作用,NFX分子中的平面结构插入DNA的双螺旋碱基平面,为深入了解喹诺酮类抗生素的抗菌机理提供可靠依据.     

A note on the crossed product R(A, α) associated with PSL_2(R)

Given the hyperbolic measure dxdy/y2 on the upper half plane H, the rational actions of PSL2(R) on H induces a continuous unitary representation α of this group on the Hilbert space L2(H, dxdy/y2). Supposing that A = {Mf : f ∈ L∞(H, dxdy/y2)}, we show that the crossed product R(A,α) is of type I. In fact, the crossed product R(A,α) is *-isomorphic to the von Neumann algebra B(L2(P,ν))■LK, where LK is the abelian group von Neumann algebra generated by the left regular representation of K.     

Size effect of fullerene cages and encaged clusters in M_3N@C_(2n)

Based on the calculated findings that the sizes of encaged clusters determine the structures and the stability of C80-based trimetallic nitride fullerenes (TNFs), more extensive density functional theory calculations were performed on M3N@C68, M3N@C78 and M3N@C80 (M=Sc, Y and La). The calculated results demonstrated that the structures and stability undergo a transition with the increasing of the sizes of the cages and clusters. Sc3N is planar inside the three considered cages, Y3N is slightly pyramidal ins...     

狭窄流道中Fahraeus效应研究进展

本文详细论述了毛细管和二维狭缝中流过血液时的Fahraeus效应研究历史及现状,给出了迄今为止得到的全部结论,并报道了笔者对狭缝缝隙中Fahraeus效应研究的最新进展。本文所涉及的内容对于微循环的理论与应用以至有关流变学仪器的设计优化都有重要意义。     

数字微镜近红外光谱仪光学系统设计与实验

针对传统光谱仪体积大、成本高、检测速度慢、需样品前处理等不足,提出了利用数字微镜面阵(DMD)实现光谱谱面分割分时选通的近红外光谱仪光学系统.首先,对比传统光路介绍单探测器微型光谱仪系统测量原理;然后结合DMD特性提出光路方案,根据几何光学原理进行初步光学元件选型和光路结构设计,利用ZEMAX光学软件对光路进行仿真,确...     

Intensity and spatial correlation properties of tightly focused partially coherent radially polarized vortex beams

By expanding the Debye theory into the tight focusing of partially coherent field, the intensity and spatial correlation properties of partially coherent radially polarized vortex beams are studied. Expressions are derived for the intensity distribution and the spectral degree of coherence in the focal region. It is found that the intensity and the transverse and longitudinal coherence degrees in the focal region change with the variation of the topological charge and coherence length of the vortex beam. In addition, the degree of coherence is shown to exhibit phase singularities.