用于组织光学特性参量测量的改进型双积分球系统

研制了一套改进型的双积分球系统,通过对光源功率的监测,可以准确获取生物组织的光学特性参量.文中详细阐明了该系统的组成、原理、测量技术及获取光学特性参量的逆加折叠方法;并分两种情况,即用改进型的双积分球系统及常用的双积分球系统分别对内脂与细粒蓝的光学特性参量(632.8nm)进行了测量,结果表明改进型系统能很好消除光源波动对测量所带来的影响,所测量的数据更准确,误差更小.     

Numerical study of the effects of scatterer sizes and distributions on multiple backscattered intensity patterns of polarized light

We investigate numerically the effects of scatterer sizes on backscattered polarization patterns using the third-order scattering model developed. The calculated results show that both parallel and cross polarization patterns from water suspensions of polystyrene spheres have four-lobe structures of the azimuth dependence of intensities. Particularly, the parallel polarization pattern is sensitive to scatterer sizes, exhibiting good agreement with prior experimental measurements. Furthermore, the polarization patterns from the dysplastic and normal cells with different size distribution widths are calculated and analyzed. The results show that the polarization patterns of dysplastic and normal cells have distinct differences, which might be used for identification of the morphological structure changes of cancer, dysplasia, and regeneration cells.     

基于激光二极管光反馈效应的肌肉震颤测量系统

介绍一种测量肌肉震颤频率和幅度的无损伤、非接触光学方法。分析了在直接频率调制下 ,激光二极管中的光反馈效应 ,探讨了振动微小位移和速度的理论模型。设计并研制了一套基于光反馈效应的直接频率调制激光二极管光电探测系统。利用该系统对微弱机械振动信号进行了探测 ,表明该系统能用于肌肉震颤的测量。最后介绍了人体前臂内侧屈肌群紧张收缩时 ,肌肉震颤的光学测量结果     

高散射介质中光子扩散成像的线性平移不变性

运用微扰理论探讨了光子扩散成像的线性平移不变性,阐明了光子扩散成像用于生物组织这一高散射介质结构与功能成你的信号形成机理.光子扩散成像所得的图像是介质内部异常结构通过光子扩散成像系统的响应.光子扩散成像系统的作用可用一个脉冲响应函数来表征.     

Simultaneous compensation for spatial and temporal dispersion of acousto-optical deflectors for two-dimensional scanning with a single prism

The dispersive nature of the acousto-optical deflector (AOD) presents a challenge to applications of two sequential orthogonal AODs (a two-dimensional AOD) as XY scanners in multiphoton microscopy. Introducing a prism before the two-dimensional (2D) AOD allows both temporal and spatial dispersion to be compensated for simultaneously. A 90 fs laser pulse was broadened to 572 fs without compensation, and 143 fs with compensation. The ratio of long axis to short axis of the exiting laser beam spot was 3.50 without compensation and 1.14 with compensation. The insertion loss was 37%. Two-photon fluorescence microscopy used the compensated 2D AOD scanner to image a fluorescent microsphere, which improves signal intensity -15-fold compared with the uncompensated scanner.     

Fast and precise algorithm based on maximum radial symmetry for single molecule localization

We present an algorithm to estimate the location of single fluorescent molecule with both high speed and high precision. This algorithm is based on finding the subpixel position with maximum radial symmetry in a pixelated single molecule fluorescence image. Compared with conventional algorithms, this algorithm does not rely on point-spread-function or noise model. Through numerical simulation and experimental analysis, we found that this algorithm exhibits localization precision very close to the maximum likelihood estimator (MLE), while executes ～1000 times faster than the MLE and ～6 times faster than the fluoroBancroft algorithm.     

生物样品的散射和吸收特性对双光子激发和共焦成象深度的影响

本文研究了生物样品的散射和吸收特性对双光子激发和共焦成象深度的影响.生物组织内30μm的成象结果表明,双光子激发具有比共焦成象更深的成象深度.来自生物组织的模型实验和蒙特卡罗模拟均表明,散射和吸收的影响是导致这一特点的重要原因.     

多光子成象术中深层图象损耗恢复的研究

本文在分析混浊介质对共焦三维扫描图象衰减的基础上,建立了多光子激发荧光扫描的深层图象恢复的数学模型.依照此模型对深层图象进行依赖组织光学参量的恢复,并给出了猪表皮三维扫描成象的恢复图象.     

混浊介质多光子激发显微成像的快速模型

将二维点扩散函数（PSF）和蒙特卡罗方法相结合,引入了一种研究混浊介质显微成像的快速仿真模型,将该模型用于混浊介质的多光子激发（MPE）显微成像研究,极大地提高了模拟效率,与直接蒙特卡罗方法计算结果的比较证实了该方法的正确性和有效性,此外,一个计算实例说明了混混介质的多光子激发显微成像具有比共焦荧光显微成像更优的横向分辨率。     

Catalyst-free fluorinative alkoxylation of alkenes

The fluorinative alkoxylation of simple alkenes under catalyst-free conditions was achieved. Various substituted olefins, including terminal and internal alkenes, and oxygen-containing nucleophiles were compatible with the standard conditions, and gave a variety of β-fluoroethers in good to excellent yields. Notably, the alkynyl and chloride-containing nucleophiles were well tolerated. In addition, acetic acid and TsNH₂ could be also used as nucleophiles and successfully afforded the desired products in good yields.