PS/PMMA复合材料的光散射

对以聚苯乙烯(PS)和自行合成的纳米"类双亲"PMMAPS为光散射剂,以聚甲基丙烯酸甲酯(PMMA)为基体的复合光散射材料进行了实验研究.测试并分析了样品的雾度及透光率与添加量之间的关系,目的在于通过调节散射剂添加量来调控以PMMA为基体的高聚物材料的光散射性能.实验结果表明,添加少量PS到PMMA中即可制备出光散射材料,PS添加量为1%时,复合光散射材料的透光率为80%;不添加PMMAPS时雾度为50%,添加了PMMAPS时雾度达到80%,PMMAPS可以改善PMMA和PS之间的相容性,提高样品的雾度值.因此通过调节散射剂PS和PMMAPS添加量可实现光散射高雾度和高透光率的双高要求.     

慢光产生的新机理及其应用

通过对比和研究电磁感应透明、相干布居振荡、受激布里渊散射和光子晶体波导等几种使光速变慢的主要技术，论述了近10年中的慢光技术重要理论和技术上的发展以及这些发展对慢光性能的改善及存在的问题与不足，重点介绍了近几年慢光产生的一些新技术及初步应用，并预测了慢光技术今后的发展趋势及潜在应用。本文的研究表明，慢光在光纤传感以及其它领域中将会有越来越重要的应用价值。     

皮秒光泵氢喇曼散射激光的研究

用ＰＳ量级５３２ｎｍ光泵浦高压Ｈ２，产生了１－３阶ｓｔ光和１－３阶ａｓ光，用ｐｓ量级１０６４ｎｍ光泵浦放有波导管的喇曼池，得到波长为９．１８μｍ的中红外喇曼光。研究能量转换效率与压力、波导管等其它因素的关系，以及泵浦能量阈值与压力的关系，实验结果与理论分析相符合。     

光散射在线分析系统

光散射在线分析系统是以斯坦教授的小角光散射法为理论基础，主要用于高分子材料内部结构的在线分析测试与研究。它是由硬件──光散射在线分析仪和软件──数据采集处理系统两大部分组成。该系统首创了高聚物内部结构的在线分析，并且成功地将数字图象处理技术应用于光散射图象的分析处理；由于计算机的优势和潜力，使得整个计算处理准确、快速，形象、直观，而且易于统一标准，从而提高了计算结果的可比性和可信度。     

布里渊散射分布式光纤传感器研究现状与展望

布里渊散射分布式光纤传感器在结构健康监测领域具有广阔的应用前景。阐述了布里渊散射分布式光纤传感器的原理,分析了基于布里渊光时域反射、布里渊光时域分析和布里渊光频域分析的分布式光纤传感技术的研究现状,提出了布里渊散射分布式光纤传感器的研究热点及存在的问题,并对其发展趋势进行了展望。     

光纤式动态光散射系统综述

动态光散射技术是探测悬浮液中亚微米颗粒动力学性质的最有效方法。光纤的使用使得小型、便携及在线式动态光散射仪器成为可能。首先指出了多模光纤动态光散射系统的缺点,然后详细分析了各种单模光纤动态光散射系统的结构特点,最后指出了目前光纤式动态光散射研究的发展动向及其面临的问题。     

PS/PMMA复合光散射性能的研究

雾度和透光率是表征光散射材料性能的两个重要指标。对以PS作为光散射体，以PMMA为基体的复合光散射材料进行实验研究。实验结果表明：少量PS添加到PMMA中时即可以制备出光散射材料，PS添加量为1%时，复合光散射材料的透光率为80%；不添加PMMAPS时雾度为50%，添加了PMMAPS时雾度达到80%，PMMAPS可以改善PMMA和PS之间的相容性，提高样品的雾度值。因此通过调节散射剂PS和PMMAPS添加量可实现光散射高雾度和高透光率的双高要求。     

动态光散射颗粒分布软测量

考虑传统动态光散射颗粒粒度分布测量用的反演算法复杂、精度不够、抗噪能力差,本文基于大数据思想,提出了一种动态光散射颗粒分布软测量方法。该方法通过调节颗粒粒度分布形状参数获得大量自相关函数及其对应颗粒分布的数据;使用这些数据对子学习机进行训练。最后,针对训练数据维数较高的特点对传统Bagging算法进行改进,并利用改进的Bagging集成算法集成子学习机以提高软测量模型的精度及泛化能力。通过模拟单峰数据和对300nm标准粒径进行软测量开展了验证实验。结果表明,该方法能够较好地测量出不同动态光散射颗粒分布的峰值及分布宽度,模拟单峰数据测量峰值精度可达1nm,300nm和503nm,标准粒径测量精度分别可达3nm和4nm,优于一般的反演算法。该软测量方法为动态光散射颗粒分布测量开辟了新的途径。     

光散射粉尘测试仪的发展现状与趋势

光散射粉尘测试仪是一种广泛应用的粉尘浓度测试仪器。本文简要介绍了光散射粉尘测试仪的工作原理和结构特点,概述了国内外光散射粉尘测试仪的发展现状与技术特点,并指出光散射粉尘测试仪存在的问题及其将来发展的方向。     

人血红细胞光散射及蒙特卡罗仿真

本文用反常衍射(anomalous diffraction)理论分析了人体血液中静态红细胞和在剪切力作用下变形为椭球形红细胞的前向光散射特点,利用等体积/等表面积(V/S)光学理论模型,并采用蒙特卡罗法(Monte Carlo)对正常和变形红细胞的光散射过程和三轴参数进行了仿真计算和分析.结果表明,该理论下进行的细胞光散射分析精度与夫朗和费(Fraunhofer)衍射理论相比可提高约一倍.     

Resonance enhanced dynamic light scattering

We present a novel light scattering setup that enables probing of dynamics near solid surfaces. An evanescent wave generated by a surface plasmon resonance in a metal layer is the incident light field in the dynamic light scattering experiment. The combination of surface plasmon resonance spectroscopy and dynamic light scattering leads to a spatiotemporal resolution extending a few hundred nanometers from the surface and from microseconds to seconds. The comparison with evanescent wave dynamic light scattering identifies the advantages of the presented technique, e.g., surface monitoring, use of metal surfaces, and biorelevant systems. For both evanescent wave geometries, we define the scattering wave vector necessary for the analysis of the experimental relaxation functions.     

Dynamic light scattering in turbid nonergodic media

We here present a new device based on dynamic light scattering (DLS) for measuring kinetics in turbid and nonergodic systems. This flat cell light scattering instrument has been developed in our laboratory and is based on an original flat cell instrument employing cells of varying thickness in order to measure the static structure and dynamics of a system. The smallest cell thickness is 10 microm. To this original instrument, we have integrated the three-dimensional (3D)-DLS technology as well as the echo method, and in comparison with other 3D-DLS instruments, ours show the best performance; the maximum intercept was 0.6 as opposed to 0.15 for regular 3D-DLS devices (recently we reached beta=0.75). This was made possible by using crossed polarization filters for the two laser beams, thereby allowing the scattered light from both laser beams to be decoupled and the intercept to no longer be limited at the theoretical value of 0.25. The maximum weight fraction of the sample that is measurable with such a setup is more than ten times higher than with a standard 3D-DLS setup or with the flat cell instrument without the 3D technology. Consequently, with the 3D-DLS flat cell instrument presented here, it truly becomes possible to investigate turbid systems. Moreover, the echo method was integrated to enable measurements of nonergodic systems. Here, a new mechanical design of the echo-DLS component was necessary due to the different geometries of the flat cell in comparison with that of a standard cylindrical cell. The performance of our echo device was compared to that of our multispeckle instrument, and the results were in good agreement for correlation times up to 30,000 s and more. The main limitation of this instrument in its current version is the maximum scattering angle of about 50 degrees (or 30 degrees if echo is used).     

Low-frequency Raman scattering of light by silver nanoparticles

Silver nanoparticles sprayed onto a crystalline quartz substrate are characterized by means of the low-frequency Raman scattering. Contributions of silver nanoparticles of different sizes to the Raman scattering spectrum are estimated. Data of scanning electron microscopy are used to verify the validity of the results obtained.     

Analysis of light scattering by rough manufactured surfaces

The relationship between the roughness of a manufactured surface and the angular distribution of the light scattered by that source is presented. A one-dimensional rough surface model is considered. It has been found that the angular distribution of the light scattered in the Fraunhofer zone is proportional to the square of the Fourier transform modulus of the surface reflection function. If the peak-to-valley height of the surface roughness is small compared with the light wavelength, the angular distribution of the light scattered is proportional to the power spectrum of the profile. If the peak-to-valley height of the surface roughness is comparable with or greater than the light wavelength, the angular distribution of the light scattered can be determined by using the suggested light scatter simulating system.     

激光光散射系统的标定与调试

激光散射是研究液体中高分子和亚微米颗粒动态行为的最有效方法之一。讨论了标定与调试激光光散射系统的理论依据。结合实践介绍了标定与调试激光光散射系统的原理和方法。给出了一个实际例子。     

激光光散射仪及应用

介绍激光光散射仪的测定原理,常用测定仪器、测定方法以及在聚合物研究中的实际应用。     

Miniaturized dynamic light scattering instrumentation for use in microfluidic applications

Five designs for a miniaturized dynamic light scattering (DLS) instrument are described that incorporate microfluidic flow of the sample volume and fiber optic probes directly embedded into the sample. These instruments were demonstrated to accurately determine the size of 10-100 nm particles dispersed in organic and aqueous solvents with most sample sizes less than 150 microl. Small stir bars were incorporated directly into the instruments, and enabled blending of different solutions immediately prior to DLS measurements. Demonstration of the instruments' capabilities include high throughput measurements of the micelle to unimer transition for poly(styrene-b-isoprene) in mixed toluene/hexadecane solvent, obtained by systematically blending toluene-rich and hexadecane-rich polymer solutions. The critical solvent composition was quickly identified with less than 20 mg of polymer. Further capabilities include temperature control, demonstrated by identification of a critical micelle temperature of poly(ethylene oxide-b-propylene oxide-b-ethylene oxide), as well as multiangle DLS measurements.     

光学粉尘浓度测量仪响应特性曲线的计算与分析

根据 Mie散射理论计算了 5种光学粉尘浓度测量仪的光散射响应特性曲线 ,对照呼吸性粉尘在人体呼吸道中的沉降效率曲线 ,对这些光学粉尘浓度测量仪的响应特性进行了分析。得出的结论是 :采用近前向型光散射结构、多波长照明光源和大孔径散射光收集系统的光学粉尘浓度测量仪 ,其响应特性曲线更接近于人体对呼吸性粉尘的采集效率