分布式光纤瑞利背向散射光子温度传感器系统的研究

分布式光纤瑞利背向散射光子温度传感器系统的研究     

全息窄带带阻滤光片用于拉曼光谱测试仪

在测量物质的拉曼光谱时,存在着比拉曼散射光强103~06倍的瑞利散射光,会严重影响拉曼光谱信号的获取。为此,研制了半宽度分别为18nm(峰值波长532nm)和25nm(峰值波长633nm)、光学密度均大于4的重铬酸盐明胶全息窄带带阻滤光片,并将它们用于由平场光谱仪、CCD探测器和计算机控制系统等组成的小型拉曼光谱测试仪中,以滤除瑞利散射光,获得信噪比较高的拉曼光谱信号。对四氯化碳、乙醇以及丙酮等液体样品进行测量的结果表明,在拉曼光谱测试仪中采用该全息窄带带阻滤光片后,可快速测得待测样品的波数低至217cm-1的拉曼光谱。     

邻菲罗啉共振光散射光谱法测定痕量镉的研究

基于镉与KI、邻菲罗啉形成多元配合物导致体系共振光散射强度增强,并且随着Cd2+浓度的加大,共振光散射的强度逐渐增大,建立一种邻菲罗啉共振光散射光谱法测定痕量镉的新方法。室温下,采用邻菲罗啉,pH=7.0条件下,在λ=397.6 nm处,Cd2+的加入浓度与共振光散射强度呈良好的线性关系,方法线性范围为0.01～6.5μg/mL,相关系数r=0.999 1,检出限0.06μg/mL,样品加标回收率为96.0%～102.8%。该法用于实际样品废旧电池中痕量镉的分析,效果较好。     

同步辐射的基本知识 第四讲同步辐射中的光谱术及其应用（五）

8Raman谱和非弹性散射谱8．1Raman谱（1）Raman效应1928年,印度物理学家Raman发现,当单色光作用于试样时会产生散射光。在散射光中,除了与入射光具有相同频率的Rayleigh散射光外,还发现有一系列其他频率的散射光,这些散射光对称地分布在Rayleigh散射光的两侧,且其强度要比Ray—leigh光低得多,通常只为Rayleigh光的10^-6～10^-9国倍,这种效应称为Raman效应。其中波长比Rayleigh光长的称为Stockes线,而波长比Ray—leigh光短的称为反-Stockes线。表1给出Raman散射和Rayleigh散射的能量转移模型。     

基于拉曼散射分布式光纤测温系统的理论分析

对分布式光纤测温系统涉及的光时域散射技术与自发拉曼散射进行理论分析,给出拉曼散射的定量描述,论述了斯托克斯拉曼散射光与温度的关系,纠正了斯托克斯光与温度无关的错误认识,统一了理论与实际应用中关于斯托克斯光与温度关系的认识,最后确定了利用反斯托克斯拉曼散射光功率曲线解调瑞利散射光功率曲线的表达式,为分布式光纤测温系统进行温度解调提供参考.     

超细银粉

超细银粉是电气和电子工业的重要材料，是电子工业中应用相当广泛的一种贵金属粉末。纳米银粒因其特殊的结构，使之产生小尺寸效应、量子尺寸效应、表面效应和宏观量子隧道效应，从而具有传统材料所不具备的物理、化学性质。纳米银粒子在表面增强拉曼光谱、表面增强共振散射光谱、分子生物学、超分子体系等领域占有极为重要的地位，[第一段]     

银纳米球阵列的局域表面等离子体特性研究北大核心CSCD

基于金属纳米颗粒的光散射理论,利用时域有限差分法计算了Ag纳米球阵列不同结构参数下的散射光谱、吸收光谱及散射效率,分析了Ag纳米球阵列在共振波长下的极化电场和极化电荷分布情况,讨论了Ag纳米球阵列的局域表面等离子体(LSP)对GaN基LED发光效率增加的机理。结果表明,随着间距的减小,Ag纳米球阵列LSP的散射峰逐渐呈双模分布,且位于长波段的散射峰蓝移;随着Ag纳米球直径的增大,LSP的共振波长红移且散射效率增大。当LSP的共振波长与LED辐射光波长相匹配时,Ag纳米球阵列的LSP与LED辐射光发生耦合作用,在一定条件下,部分耦合的能量辐射到自由空间,增大LED的内量子效率。     

银纳米球阵列的局域表面等离子体特性研究

基于金属纳米颗粒的光散射理论,利用时域有限差分法计算了Ag纳米球阵列不同结构参数下的散射光谱、吸收光谱及散射效率,分析了Ag纳米球阵列在共振波长下的极化电场和极化电荷分布情况,讨论了Ag纳米球阵列的局域表面等离子体(LSP)对GaN基LED发光效率增加的机理。结果表明,随着间距的减小,Ag纳米球阵列LSP的散射峰逐渐呈双模分布,且位于长波段的散射峰蓝移;随着Ag纳米球直径的增大,LSP的共振波长红移且散射效率增大。当LSP的共振波长与LED辐射光波长相匹配时,Ag纳米球阵列的LSP与LED辐射光发生耦合作用,在一定条件下,部分耦合的能量辐射到自由空间,增大LED的内量子效率。     

地震动频谱特性及与隔震结构损伤相关性研究

针对地震动频谱特性的描述方法及频谱特性与结构损伤的相关关系进行了研究。提出了Fourier谱强度频率匹配度、结构振型频率影响系数和类共振放大系数的概念及计算公式;以基础隔震结构作为弹塑性时程分析模型,计算结构整体损伤指数;最后,分别从卓越频率、三大峰值频率和平均频率三个角度研究地震动频谱特性与结构损伤的相关性。研究结果表明:地震动频谱特性对结构造成的损伤与结构各阶振型频率有关,且第一振型频率影响最大;Fourier谱强度频率匹配度越大,表明结构发生类共振的概率越大,造成隔震层和上部结构的损伤也越大;类共振放大系数反映频谱特性对结构造成损伤的程度,平均频率类共振放大系数与结构损伤的相关性最好,用平均频率能够较好地描述地震动的频谱特性。     

扩散火焰中初始形成碳核的光学测量

根据米氏散射理论 ,推导出碳核的散射属于瑞利散射。介绍一种实验方法 ,该方法利用在入射光为偏振激光时碳核的瑞利散射光与碳核原始化合物 PAH辐射的荧光的差异 ,测量扩散火焰中形成的碳核     

Scattering of elastic waves by spherical inclusions with applications to low frequency wave propagation in composites

Scattering of plane elastic waves by a spherical inclusion is considered. A unified method of solution is presented which treats compressional and shear incidence on a similar basis. Explicit results are given for Rayleigh scattering. We apply the results of the single scattering problem to the propagation of low frequency waves in a composite containing a dilute concentration of spherical inclusions. Explicit formulae are given for the effective wave speeds and attenuations when the inclusions are voids. Both the compressional and shear wave speeds decrease initially as a function of frequency.     

Stray-light analysis for the SCORE coronagraphs of HERSCHEL

The HERSCHEL (Helium Resonance Scattering in the Corona and Heliosphere) suborbital mission scientific payload consists of two extreme ultraviolet (EUV) coronagraphs forming the SCORE (Sounding Coronagraph Experiment) and an EUV Sun disk imager. The mission will be of great importance for the investigation of solar wind dynamics by obtaining the first global image of the Sun (disk and corona) in the He ii30.4 nm line. The most stringent requirement for the optical design of a coronagraph is stray-light reduction. We summarize the stray-light analysis for the SCORE coronagraphs, which are characterized by an innovative optical design, optimized for stray-light reduction.     

Fictitious Rayleigh expansions

Scattering matrix and transfer matrix methods are widely used in the frame of scattering from a stack of thin films, a stack of periodic grids or photonic crystals. They allow one to reduce significantly computation time and memory storage. However, these methods have well-known theoretical limits since they require the field to take the form of plane wave expansions (Rayleigh expansions) on both sides of each element of the stack. It will be shown that, in fact, the domain of validity of these methods can be considerably extended by defining fictitious Rayleigh expansions between two consecutive elements, even when they are not separated by a homogeneous region. Numerical results confirm this prediction.     

静电纺丝控释材料的最新研究进展

目的 综述静电纺丝的发展和原理,控释材料和控释体系,以及静电纺丝控释材料(Electrospinning controlled-release material,ECM)在药物缓释和抗菌方面的应用,旨在为ECM的相关研究提供理论参考和研究思路。方法 通过对国内外研究成果的分析和总结,介绍ECM通过环境pH调节、羧基修饰纳米纤维、光响应、纳米纤维膜厚度、纤维表面孔隙等因素进行控制释放的应用。结果 分析表明,ECM可以应用于药物缓释和抗菌方面,可以实现药物在特定条件下的响应和释放,让药物有合适的释放周期。此外,还可以对各类抗菌剂实现控释,达到长效杀菌、延长货架期的目的。结论 研究ECM(药物缓释用),能够实现药物的可控释放,保证药效的持久性,提升治疗效果。研究ECM(缓释抗菌用)可以获得更长效的抗菌效果,提高食品和药品的卫生安全性。ECM在药物缓释和抗菌方面具有很大的发展前景。     

Synthesis,optical properties and self-assembly of gold nanorods

Noble metal nanostructures of different aspect ratios were synthesised and optically characterised at individual nanorod level. Rayleigh scattering spectroscopy/scanning electron microscopy measurements were performed to uniquely correlate optical signatures with nanorod size and shape. Scattering spectra of nanorods were dominated by the intense longitudinal surface plasmon resonance (SPR) band in the near-infrared part of the spectrum. This band was found to be highly shape and size dependent. Droplet evaporation techniques and application of dielectrophoretic forces have been used to organise nanorod dispersions into ordered arrays. Depending on the technique and nanoparticle size used, nanorods were found to form one, two or three dimensional (1D, 2D and 3D) superstructures. Within these superstructures nanorods organised themselves into end-to-end lines (1D), side-to-side fashion (2D) or hexagonal arrangements (3D).     

抑郁症药品包装的情感化设计研究

目的 探讨情感化设计在抑郁症药品包装中的运用,并分析抑郁症药品包装的情感化设计对于患者的意义与价值。方法 采用案例分析法,以情感化设计理论为出发点,从本能层、行为层、反思层三个层面对抑郁症患者的情感需求做出具体分析,并针对患者对药品包装的需求进行抑郁症药品包装的情感化设计方法分析。结论 抑郁症药品包装的情感化设计具有较高的社会价值,可以满足患者对药品包装的情感需求,并且对病情的康复起到一定的潜移默化作用。因此,站在抑郁症患者的角度来看,具有情感化的包装设计也是一味良药,设计师要转变和更新设计思路,以情感化设计理论为基点,从包装定位、图形、色彩和结构设计等方面深入研究和创新,使得抑郁症药品包装的功能和情感价值发挥到最大化,从而给予抑郁症患者更好的用药服务。     

生物降解高分子材料--聚酸酐的研究进展

聚酸酐由于其具有良好的表面溶蚀性能，作为药物控释体材料得到广泛的应用。文中综述了生物降解医用高分子材料——聚酸酐的分类、制备方法、研究进展及应用等．并提出了今后的发展方向。     

多孔碳纳米材料构建抗肿瘤药物靶向传递系统的研究进展

抗肿瘤药物靶向传递系统是提高传统化疗药物疗效,并降低其毒副作用的重要手段。以多孔碳纳米材料为药物载体,根据肿瘤组织微环境特点,构建抗肿瘤药物靶向传递系统是实现靶向治疗方案的有效方式。本文围绕基于多孔碳纳米材料的抗肿瘤药物靶向传递系统的构建及应用进行综述,描述了多孔碳纳米材料适宜载药的设计、合成及功能化修饰;通过理论与实例相结合的方式,介绍了提高多孔碳纳米材料载药量和实现联合给药的有效策略;从内源和外源性敏感刺激的角度,重点分析了多孔碳纳米材料基于肿瘤微环境构建的靶向传递系统的机制和应用;阐述了多孔碳纳米材料作为抗肿瘤药物载体面临的生物相容性和生物降解性的问题,并分析了可能的解决途径;展望了多孔碳纳米材料在构建肿瘤药物靶向传递系统应用中的前景及发展方向,为研发靶向、可控的抗肿瘤药物传递系统提供了理论依据和例证支持。     

Transmitted scattered light from a thin film with shallow random rough interfaces

The transmitted scattered energy of plane electromagnetic waves from a thin metallic film with shallow rough interfaces bounded by two semi-infinite media is calculated. Both interfaces are modeled as independent stationary random processes with a Gaussian roughness spectrum. Scattering of light is calculated for both TM (p) or TE (s) polarizations for normal and oblique angles of incidence. An integral equation is obtained for the transmitted field based on the Rayleigh method and their solution involves Fourier coefficients, depending on the roughness profiles. We present some results for the case of a single thin metallic film in the attenuated total reflection configuration for s and p polarization around the angle of the excitation of surface-plasma waves θ(sp). The transmitted scattered intensity shows a maximum at the resonant angle θ(sp) in the case of p polarization.     

Improved route for the synthesis of colloidal NaYF4 nanocrystals and electron spin resonance of Gd3+ local probe

This paper presents the synthesis and characterization of colloidal NaYF4 and NaYF4:20% Gd lanthanide nanocrystals. The nanoparticles were prepared by chemical route using co-thermolysis of Na(CF3COO), Y(CF3COO)3 and Gd(CF3COO)3 precursor in oleylamine surfactant/phenylether at Ts = 250 degrees C. By tuning the precursor/surfactant molar ratio during the process, it was possible to control the crystalline phase, chemical order and size of the nanocrystals. The nanocrystals were characterized by Transmission Electron Microscopy, Small Angle X-ray Scattering, powder X-ray Diffraction, dc-magnetization and Electron Spin Resonance (ESR) techniques. The ESR experiments show the so called U-spectrum for the Gd3+ ions in bulk counterpart materials, where characteristic powder spectra of cubic and lower crystal field symmetries were observed.