Quantitative analysis of the self-absorption and reemission effects on the emission spectrum of photoluminescence in right-angle excitation–detection configuration

A theoretical approach based on differential radiative transport is proposed to quantitatively analyze the selfabsorption and reemission effects on the emission spectrum for right angle excitation–detection photoluminescence measurements,and the wavelength dependence of the reemission effect is taken into account.Simulations and experiments are performed using rhodamine 6G solutions in ethanol as model samples.It is shown that the self-absorption effect is the dominant effect on the detected spectrum by inducing pseudo red-shift and reducing total intensity;whereas the reemission effect partly compensates for signal decrease and also results in an apparent signal gain at the wavelengths without absorption.Both effects decrease with the decrease in the sample concentration and the propagation distance of the emission light inside the sample.We therefore suggest that diluted solutions are required for accurate photoluminescence spectrum measurements and photoluminescence-based measurements.     

基于瞬态光克尔效应的超快光学快门技术

系统介绍了几种基于瞬态光克尔效应的超快光学快门技术,包括传统的光克尔双折射快门技术,瞬态光栅快门技术,以及利用瞬态克尔透镜效应的光学快门技术。这些技术都是在泵浦-探测的实验配置基础上,利用门控光对克尔介质折射率的瞬态调制导致的信号光的相位（偏振态）、传播方向或光束发散角等光学特性的改变实现对信号光的超快时间分辨测量。对比讨论了这些超快快门技术的工作原理和实验配置,结果表明瞬态光束偏折快门技术相比其他快门技术具有无偏振配置要求、无相位匹配条件、超宽带光谱响应范围的特点,在光与物质相互作用的超快动力学研究中具有更为广阔的应用前景。     

慢性肝病患者血中TNF、LPO水平的变化及其相互关系

为探讨脂质过氧化与肿瘤坏死因子（ＴＮＦ）释放之间的关系,观察了７２例慢性肝病患者抗氧化治疗前后血中过氧化脂质（ＬＰＯ）和ＴＮＦ水平。结果表明,治疗２～３月后,所有患者血中ＬＰＯ、ＴＮＦ水平均下降,以补硒抗氧化治疗组最明显,与常规治疗组比较有显著差别（Ｐ〈０．０５）。提示慢肝患者体内脂质过氧化状态可能影响免疫介质ＴＮＦ的释放。     

硒对人肝细胞缺氧-复氧损伤的影响

建立人肝细胞缺氧－复氧损伤模型,观察了微量元素硒的保护作用。结果表明,模型组肝细胞内、外丙二醛水平均显著增高,丙氨酸转氨酶外释增多,白蛋白合成减少,与正常对照组比较,差异有显著性意义（Ｐ＜００１）。１１５６×１０－７ｍｏｌ／Ｌ硒预保护组上述损伤变化明显减轻（Ｐ＜００５）。揭示硒对缺氧－复氧所致人肝细胞脂质过氧化损伤具有保护作用。