偏振差分反射光谱研究半导体材料的平面内光学各向异性

介绍了偏振差分反射光谱的原理,并结合半导体材料平面内光学各向异性的来源,总结了偏振差分反射光谱作为一种重要的表面、界面分析技术在半导体材料研究中的应用,并分析指出其在Si基材料电光改性研究中将会起到重要作用。     

基于反射光谱吸收特征勘探天然气的方法研究

反射光谱学提供了一种高效和低成本的鉴别物质成分和结构的方法;油气微渗漏理论则建立了油气藏与其上部地表的特定异常之间的因果关系。因此,可以通过检测地表异常的反射光谱来勘探油气。野外实地测量和高光谱遥感均能够实现反射光谱的检测。文章通过对青海某地区野外测量的反射光谱的分析,首先提出了典型气田区测点的光谱曲线的宏观吸收特征;然后,完成了反射光谱中的吸收特征的提取,包括吸收波段深度、位置、宽度和对称度,以此分析测区采集的样品光谱,建立了该地区的特征光谱库;提出了检测地表烃类物质的方法;最后基于线性解混模型,实现了半定量地提取测区主要蚀变矿物的丰度信息。     

黄铁矿处理重金属废水的光谱表征

将反射光谱和吸收光谱用于黄铁矿处理酸性重金属废水的研究,探讨了黄铁矿的表面反应以及黄铁矿与重金属的相互作用。漫反射红外光谱分析证实,在处理废水过程中,黄铁矿中表面羟基与重金属离子发生反应;并通过考察黄铁矿中碳酸盐,合理解释了黄铁矿处理酸性重金属废水后的溶液自然均趋于中性(pH 7)的现象。可见区的反射光谱用于表征处理过程中的黄铁矿的颗粒及比表面变化,解释了黄铁矿在重复使用时其活性反而增强的原因。吸收光谱及XPS表征表明,黄铁矿处理含Cr(Ⅵ)废水,是一个由Cr(Ⅵ)到Cr3+再到Cr(OH)₃的吸附沉淀过程。     

Reflection, transmission and circular dichroism in axially excited slab of a copper thin film helicoidal bianisotropic medium

The reflectance, transmittance and circular dichrosim in a chiral sculptured copper thin film slab of 1000-1600 nm thickness in near infra-red and visible regions based on the relative permittivity of copper in the bulk state and volumetric fraction of copper inclusion of 0.2 are obtained. At higher volumetric fraction of metallic inclusions the reflection (due to low circular Bragg phenomenon) and transmission coefficients (due to increased absorption) are too small, while for thicker slabs numerical instabilities (overflow/underflow) occur in the computation. Therefore it is recommended that the chiral sculptured thin film slab to be considered as a half space.     

Enhanced polarization conversion for an anisotropic thin film

This work presents an explicit expression for the reflection and transmission coefficients of an anisotropic thin film in the general case in which the optical axis and the incident ray are arbitrarily directed in three dimensions. The polarization conversion quantities for reflected light from an anisotropic thin film are calculated and analyzed for two three-layered systems. With light incident from a dense medium, polarization conversion will be enhanced at a particular incident angle that exceeds the critical angle.     

On the morphology of stain-etched porous silicon films

Morphology of stain-etched porous silicon films was investigated by a non-destructive technique, based on reflectance spectrometry: dielectric function profiles were computed by spectral reflectance via a finite difference model, and porosity was deduced by the effective medium approximation. Theoretical calculations were supported by high-resolution electron microscopy observations. The relations among oxidising species concentration in the etching solution, porosity profile and surface reflectance of the films were investigated.     

荧光熄灭法测定前列腺素E1

本文研究了前列腺素Ｅ１（简称ＰＧＥ１）对甲醇荧光峰的熄灭作用，且其熄灭程度与ＰＧＥ１浓度间有较好的定量关系，线性回归方程为ΔＦ＝０．２２２ｃ＋９．３３×１０－２（ΔＦ为荧光熄灭值；ｃ为ＰＧＥ１浓度，单位为μｇ／ｍＬ），回归系数ｒ＝０．９９９３０。实验表明，用该法所得结果与紫外分光光度法所得结果较相吻合。     

Reflectance difference spectroscopy study of Ag growth on W(1 1 0)

We report a reflectance difference spectroscopy (RDS) investigation of the epitaxial growth of Ag on the W(1 1 0) surface. Monitoring the growth in real time, the RDS signal at 4.6 eV shows an oscillatory behavior corresponding to the layer-by-layer growth of the first three monolayers. The oscillations are attributed to the variation of the optical anisotropy contributed by the W(1 1 0) substrate and the Ag film. By analyzing the spectral evolution during growth, characteristic optical-electronic fingerprints can be deduced for each added atomic layer. In particular, the binding energy of d-like quantum well states has been used as an indicator for the number of Ag atomic layers and, hence, as a sensitive probe of the Ag thin film growth.     

反射薄层光谱电化学方法的应用

用自行设计的反射光谱薄层电解池测定了二茂铁在NaClO_1/CH_3CN中的E~O′和n值、铁氰化钾在KCl底液中和亚甲蓝在KNO_3/DMSO中的扩散系数。对亚甲蓝在二甲亚砜介质中的还原过程进行了研究,证明有一电子还原产物存在。     

Surface composition of alloys

The practical importance of alloy surfaces in catalysis, corrosion andother aspects of materials performance is widely recognized. What is needed now is sufficient knowledge of the relationship between externally controllable factors — alloy composition, temperature, environment — and surface properties — composition, structure, chemical activity — to control materials performance in these applications. Our purpose here is to review progress in determining and predicting the relationship between one surface property, composition, and certain externally controllable variables: overall composition, temperature, environment and physical form.We find that theoretical treatments of metal alloy surface composition now include essentially all significant physical effects and can predict values for most parameters of interest. Though improvements are still possible, the accuracy of predictions is more often limited by uncertainties or absence of the basic data for the calculations (e.g., thermochemical values) than by the models themselves.Alloy surface composition can now be measured well. The first monolayercomposition of large alloy slabs can be determined quantitatively over a wide temperature range in ultra-high vacuum. Difficulties with specimens of practical interest still challenge experimentalists. Among these are supported catalysts, surfaces under chemisorbed layers and composition of layers below the first. Significant progress is being made and we expect the next few years will see success.