Experimental Study on Light Scattering of High Concentration Suspension

To understand the optical properties of living tissue in the NIR range, it appeared informative to investigate the scattering properties of high concentration particle suspension. We measured the angular light scattering of aqueous suspension of 3.5 μmφ polystyrene particles contained in a 60 μm thick cuvette up to 50% volume concentration at 805 nm wavelength using a goniophotometer. We found that the discrepancy between the measurement and the Monte Carlo simulation becomes larger with increased concentration, which is attributable to the phase function change as well as the scattering coefficient change.     

铜绿微囊藻吸收和散射特性理论模拟

基于奇异衍射近似理论和Kramers-Kronig关系,通过实测铜绿微囊藻的吸收光谱数据和粒径分布估算出铜绿微囊藻折射率的实部和虚部,结合Mie散射理论,计算出铜绿微囊藻的吸收效率光谱、散射效率光谱。对比模拟结果与实验结果发现:该模型估算得到的散射光谱与实验的散射光谱之间误差为10.08%,吸收效率的误差为4.8%。从模拟结果与实测结果来看,均匀球形模型能够较好的重现铜绿微囊藻的吸收和散射特征。     

双轴晶体会聚偏光干涉的理论与实验研究

晶体会聚偏光干涉图包含了晶体特性的许多信息,建立偏光干涉图的定量分析方法可以使这些信息得到充分利用。基于双轴晶体折射时满足的波矢关系,导出了两折射光波相位差的精确计算公式。分析了光波在各界面折射时偏振态的变化,提出了会聚偏光干涉合成振幅的计算方法。针对任意取向的双轴晶体,计算了完整的偏光干涉图,反映了相位分布决定等色线、振幅分布决定消光影的规律。用数字图像模似了干涉图,并讨论了干涉图的变化情况。对4块不同取向的KTP晶片进行实验,实验干涉图与理论干涉图的特征完全一致,两者仔细对比可判断现有KTP晶体色散方程的优劣。     

入射波整形技术的实验和理论研究

 在硅橡胶材料的分离式霍普金森压杆实验中,实验研究了如何实现常应变率加载,并且得到了整形器尺寸与加载应变率之间,以及加载应变率与试样厚度之间的定量关系。根据预估入射波形的理论模型,给出了采用H62黄铜整形器整形后入射波形的计算结果和实验结果,二者基本上是一致的。     

共振光散射技术测定核酸的研究进展

核酸分析是生命科学研究中最重要的技术之一。目前主要是应用核酸内源紫外吸收光谱的紫外分光光度法和基于荧光探针分子与核酸相互作用的荧光分光光度法。紫外分光光度法灵敏度低 ,荧光分光光度法试剂昂贵 ,有毒性。近年来 ,共振光散射技术在核酸分析中的应用得到了迅速的发展。核酸的共振光散射分析方法可以用普通的荧光分光光度计进行测定 ,应用安全、便宜的试剂获得很高的灵敏度。简要介绍了共振光散射分析的基本原理 ,并对近年来利用共振光散射技术分析核酸的研究进行了评述。内容主要包括利用有机染料分子作为核酸的共振光散射探针的分析方法 ;基于阳离子表面活性剂、金属离子及其络合物以及药物与核酸相互作用的分析方法 ;核酸形成大粒子的散射分析方法。     

光学扩散特征的生鲜肉细菌总数的无损检测方法

细菌总数是生鲜肉的最主要安全参数之一,肉品的光学扩散特征反映其细菌总数。对高光谱扩散数据利用不同的拟合算法处理与分析,并比对生鲜猪肉细菌总数建模的相关性差异,确定了用于最终建模的最佳扩散特征参数,为后续的装置开发提供建模依据。冰箱调至4℃恒温,在里面放置63个分割好的猪肉样品,每天间隔固定时间从里面随机取出4~5块样品,获取猪肉表面的400~1 100nm波长范围内高光谱散射图像,从高光谱图像中提取猪肉的扩散光谱曲线,利用Lorentz函数和Gompertz函数以及修正后的函数,拟合处理与分析扩散数据,拟合后的不同参数可以代表样品的特征光谱,细菌总数的标准值用平板计数法获得,然后单独用各单个参数、多个参数结合的方式,多元线性回归的统计方法,与细菌总数分别建立模型。实验结果表明,Lorentz三参数结合,Lorentz四参数结合,Gompertz四参数拟合的模型相关系数较高,其校正集和预测集相关系数分别为0.93,0.96,0.96和0.90,0.90,0.92,标准偏差分别为0.47,0.44,0.39和0.56,0.46,0.42,其中,相关性最好的是Gompertz四参数结合,在装置的开发中可以优选相关性和稳定性最好的模型导入装置系统中。     

用铀试剂Ⅰ共振光散射法测定蛋白质的研究

本文提出一种新的光散射探针染料--铀试剂Ⅰ(ArsenazoⅠ),在pH 3.29 的条件下,ArsenazoⅠ本身只有极弱的光散射,它与蛋白质的结合物有强烈的共振光散射作用.在λ=400 nm处,光散射有最大强度,光散射强度与蛋白质的浓度成正比.据此建立了一种测定蛋白质的新方法.该方法简便、快速、灵敏度高,对HSA的检测限达到60 ng*mL-1, 线性范围达到0～18 μg*mL-1, 用于人体血清样品的分析并同考马斯亮蓝法比较,取得了令人满意的结果. 本文也研究了牛血清白蛋白(BSA)、γ球蛋白、鸡蛋白蛋白、溶菌酶、胃蛋白酶与染料ArsonazoⅠ之间的作用,探讨了共振光散射的机理.     

Improving the Sensitivity of Forward Light Scattering Technique to Large Particles

The detection of a small number of large particles whose size lies outside the required size distribution is important in the processing of many materials when those particles result in the deterioration of the product quality. Laser diffraction, which is a very popular technique for on-line monitoring and process control, has, however, limited sensitivity to those few large particles. This paper deals with the improvement of this sensitivity. The fluctuations of the signal received by the detectors were analyzed by both experiment and simulation. Two statistical approaches, cross-correlation and principal component analysis (PCA), were applied. A detection procedure is proposed which is based on the combination of sweep selection through PCA and an appropriate deconvolution of the selected sweeps. The preliminary experiments with Al₂O₃ powder showed an improved sensitivity to the large particles.     

聚芴共轭聚合物在稀薄溶液中形态变化的静态光散射研究

PF8聚芴共轭高分子材料是应用于制作蓝色光激发光器件的一种有潜力功能材料, 故本文利用静态光散射技术研究了PF8聚芴共轭高分子在稀薄甲苯溶液中的形态结构变化特点。研究结果显示, PF8共轭高分子在甲苯稀薄溶液中单一分子链的持续长度与Kuhn链结长度均明显受到温度的影响。这表明在较高温度下高分子与溶剂间的相互作用力较大, 导致其呈现较伸展的虫状形态结构; 而在较低温度下高分子与溶剂间相互作用力较小, 导致其呈现收缩的结构形态。因此在较高温度状态下PF8共轭高分子应该具有比较刚硬的特征。     

Experimental Study of the Influence of Thickness and Wavelength on the Ultraviolet Light Scattering of Polyethylene Films

A study of the influence of thickness and wave-length on the ultraviolet scattering of polyethylene films is reported in this paper. The scatter of samples was measured by considering the difference between absorbances values obtained with the sample placed in two positions at different distance from the detector in a UV/Vis Spectrophotometer.

The present work suggests that a linear relationship exists between absorbance and thickness film for the two sample positions, and also between the difference of these absorbances and wavelength. From the obtained equations it is possible to normalize scattering values for a given wavelength and a given thickness, and in this way experimental errors are minimized. This procedure represents a simple way for characterize optically these materials and, analogously, other transparent or translucent polymeric films.     

光通过纳米颗粒随机散射体透射光强的计算及分析

光通过随机散射体后透射光强的估算,对于提取散射体内部无法直接测量或者无法直接观察的信息至关重要。在分析平行光束通过纳米圆形颗粒随机散射体出射面上光强组成的基础上推导了透射光强的计算公式,并指出多重散射理论、一阶多重散射理论和朗伯-比尔定律在一定近似程度上可以相对精确地估算透射光强。这三种方法的估算结果之间会出现四种相对关系。根据这些相对关系,分析了光在散射体内部传输时散射过程的特征以及各种散射过程对出射面光强的贡献大小。     

Theoretical and Experimental Study of Scattering of a Plane Wave by an Inhomogeneous Plasma Sphere

Scattering of electromagnetic waves by an inhomogeneous plasma sphere has been studied theoretically and experimentally. The offset angles of electromagnetic waves caused by the plasma sphere have been observed experimentally. The effects of the electromagnetic wave frequency and plasma density on the offset angle are discussed. The plasma density is estimated with the offset angle.     

Scattered Light Photometer for On-Line monitoring of size distribution parameters and particle number concentration

A scattered light photometer which monitors the particle number concentration of aerosols is described. The photometer measures the scattered light from illuminated submicron particle clouds with known material properties at certain scattering angles. Intensity ratios in combination with the degree of polarization are used to determine the mean particle diameter and the geometric standard deviation of an assumed log-normal particle size distribution. The determination of the particle size distribution is based on an algorithm which compares the measured and calculated (Mie theory) relative intensity quantities described. Furthermore, the particle number concentration is monitored from a single absolute intensity measurement at one scattering angle. In order to obtain quantitative results a spherical particle shape is required.     

利用多重光散射技术研究吡虫啉悬浮剂的物理稳定性

Turbiscan Lab稳定性分析仪利用多重光散射技术,能够准确测量乳状液、悬浮液等沉淀层、浮油层或澄清层厚度以及粒子平均粒径随时间的变化情况,定性定量分析体系不稳定性发生的机理和速率。本文利用Turbiscan Lab稳定性分析仪测定了不同萘磺酸盐分散剂GY-D10,NNO,Morwet D-425,TERSPERSE 2425制备的350 g·L-1吡虫啉悬浮剂及其悬浮液背散射光强度随时间的变化情况以及颗粒平均粒径的聚结增大速率,同时利用激光粒度分析仪测定加速试验前后颗粒平均粒径的变化情况,结果表明：添加分散剂GY-D10,用量为4 Wt%时悬浮液的稳定性最好,对应的吡虫啉悬浮剂的稳定性也最好。     

光纤中双宽带抽运SBS慢光及其脉冲展宽减小的理论研究

提出了一种单模光纤中采用双宽带抽运实现宽带受激布罩渊散射(SBS)慢光的方法.给出了双宽带抽运的SBS慢光及其脉冲展宽的理论模型.色散分析发现,两抽运光间存在一个最佳的频率间隔,可有效地减少由于群速度色散所引起的脉冲展宽.理论计算表明,该方案所获得的SBS增益带宽和信号脉冲群延迟分别提高到了相同条件下单宽带抽运的1.7倍和2倍.     

阿霉素与DNA作用的共振光散射研究及在DNA分析中的应用

研究了抗癌药物阿霉素与DNA相互作用的吸收光谱、荧光光谱和共振光散射光谱,发现阿霉素与DNA相互作用产生强烈增强的共振光散射信号,共振光散射技术在研究DNA与阿霉素的相互作用时,其灵敏度远远高于吸收光谱和荧光光谱。DNA与阿霉素作用在322与564 nm处产生两个共振散射峰,在弱酸性条件下(pH 5.72),DNA的浓度在0～8.0 μg·mL-1范围内与散射强度呈良好的线性关系,对小牛胸腺DNA和鱼精子DNA的检出限分别为36.8和40.1 ng·mL-1。由此建立了一种选择性好,灵敏度高的DNA共振光散射分析方法。     

依来铬青R-蛋白质体系的共振光散射特征及微量蛋白质的光散射法测定

基于蛋白质对有机染料依来铬青R共振光散射的增强作用 ,拟定了一种测定蛋白质的共振光散射法。在pH 4 0的酸性介质中 ,依来铬青R在 4 0 0nm处的共振光散射增强与蛋白质浓度呈线性关系 ,对牛血清白蛋白 ,测定的线性范围为 0～ 5 0mg·L-1 ,检测限 4 4 4 μg·L-1 。该方法简便 ,快速 ,灵敏 ,稳定性及选择性好 ,用于人尿样品中蛋白质含量的测定 ,结果满意     

A Review of Elastic Light Scattering Theories

Mie scattering is an important tool for diagnosing microparticles or aerosol particles in technical or natural environments. Mie theory is restricted to spherical, homogeneous, isotropic and non-magnetic particles in a non-absorbing medium. However, as microparticles are hardly ever spherical or homogeneous, there is much interest in more advanced scattering theories. During recent decades, scattering methods for non-spherical and non-homogeneous particles have been developed and even some computer codes are readily available. Extension of Mie theory covers coated spheres, stratified spheres and clustered spheres. For homogeneous non-spherical particles such as spheroids, ellipsoids and finite cylinders, surface discretization methods have been developed. Scattering by inhomogeneous particles may be computed by volume discretization methods.