Determination of Proteins by Measuring Total Internal-reflected Resonance Light Scattering Signals on Water/Tetrachloromethane Interface with Evans Blue and Cetyltrimethylammonium Bromide

A sensitive and selective assay of proteins is proposed based on measuring the total internal-reflected resonance light scattering(TIR-RLS) signals produced on the water/tetrachloromethane(H_2O/CCl_4) interface. In an aqueous medium with pH value in the range of 3.29—3.78, electrostatic attraction occurs between the negatively charged Evans Blue(EB) and positively charged proteins, forming hydrophobic ion associates and resulting in EB-protein adsorption on H_2O/CCl_4 interface. The presence of cetyltrimethylammonium bromide prompts this adsorption, resulting in strongly enhanced TIR-RLS signals. The intensity of the enhanced TIR-RLS at 360—370 nm was found to be proportional to the concentration of proteins. For bovine serum albumin and human serum albumin, the linear range of detection is 0.07—1.2 μg/mL and the limits of detection are 6.68 and 6.30 ng/mL(3σ), respectively, while for lysozyme, the linear range of detection is 0.06—1.0 μg/mL and the limit of detection is 6.0 ng/mL(3σ). The content of the total albumin in a human urine sample could be directly determined by using the standard addition method with a percent recovery of 97.6%—104.1%, and the RSD ranging from 1.9% to 4.2%.

Possible Relevance of the Allende Meteorite Conditions in Prebiotic Chemistry: An Insight into the Chondrules and Organic Compounds

The study of the mineral and organic content of the Allende meteorite is important for our understanding of the molecular evolution of the universe as well as the ancient Earth. Previous studies have characterized the magnetic minerals present in ordinary and carbonaceous chondrites, providing information on the evolution of magnetic fields. The interaction of organic compounds with magnetic minerals is a possible source of chemical diversity, which is crucial for molecular evolution. Carbon compounds in meteorites are of great scientific interest for a variety of reasons, such as their relevance to the origins of chirality in living organisms. This study presents the characterization of organic and mineral compounds in the Allende meteorite. The structural and physicochemical characterization of the Allende meteorite was accomplished through light microscopy, powder X-ray diffraction with complementary Rietveld refinement, Raman and infrared spectroscopy, mass spectrometry, scanning electron microscopy, and atomic force microscopy using magnetic signal methods to determine the complex structure and the interaction of organic compounds with magnetic Ni-Fe minerals. The presence of Liesegang-like patterns of chondrules in fragments of the Allende structure may also be relevant to understanding how the meteorite was formed. Other observations include the presence of magnetic materials and nanorod-like solids with relatively similar sizes as well as the heterogeneous distribution of carbon in chondrules. Signals observed in the Raman and infrared spectra resemble organic compounds such as carbon nanotubes and peptide-like molecules that have been previously reported in other meteorites, making the Mexican Allende meteorite a feasible sample for the study of the early Earth and exoplanetary bodies.

Emission Characteristics of the Side Radiation of Excited of the Layer of Alcohol Solution of Rhodamine 6G with the Round Geometric Shape

The spectral-spatial characteristics of the lateral radiation of a circular-shaped Rhodamine 6G solution layer were investigated. The layer is a part of the laser dye solution, which is in optical contact with the bottom of optical cylindrical cell, the shape of which determines the geometric shape of the exciting layer. Homogeneous excitation of this layer by the second harmonic of the Nd+: YAG (λ = 532 nm) laser is realized. Circular, plane-directed radiation, with a small, vertical, divergence was obtained from the edges of the excited layer. Is investigated experimentally the spectral and spatial characteristics of radiation. Excitation of the layer was performed from the side of the cuvette bottom. It turned out that within the concentrations of the dye in the solution from 0.12 to 0.03 wt%, the following processes are observed: 1) Plane-directed radiation, with a small vertical divergence, uniform in intensity, around the optical cell in the plane of the luminescent layer;2) An increase in the amplitude of radiation pulses with a decrease in the concentration of the dye in the solution;3) Shifting of the maximum of the emission spectrum to the short-wave region, significant narrowing of the radiation spectrum and decrease of the vertical divergence of radiation.

Negative refraction and reflection of Gaussian beam on two-dimensional photonic crystal slab

The refraction and reflection of Gaussian beam on two-dimensional photonic crystal （2DPC） slab are studied by the finite-difference time-domain （FDTD） method. It is shown that 2DPC slab enables negative refraction, which is demystified by the distribution of Poynting vector directions and values inside the 2DPC. A negative Goos-Haenchen shift is also found in the simulation.

Light propagation and reflection-refraction event in absorbing media

The light propagation within an absorbing medium and the reflection and refraction at the interface of two absorbing media are studied. By using the unit vectors denoting the planes of constant field amplitude and constant phase respectively, the light propagation and attenuation are described by the effective refractive indices which depend on both the complex refractive index of the medium and the angle between the unit vectors. With the expression for the light propagation, the corresponding Snell＇s law and the expression of Fresnel coefficients are obtained, which can be applied to describe the reflection-refraction event at the interface between an arbitrary combination of transparent and absorbing media.

A Simple Analytic Approximation for the Refracted Field at Gaussian Beam Incidence upon a Boundary of Absorbing Medium

An approximate analytic model is presented to describe spatial structure of refracted electromagnetic field arising at oblique incidence of a Gaussian beam on a plane boundary of an absorbing homogeneous medium. The analytic solution is obtained by asymptotic approximation of a Fourier field integral under the condition of great beam width in comparison with a wavelength (the geometrical-optics approximation). This model can be used also for approximate simulation of refracted field in the cases of beam incidence near the critical angle on transparent or absorbing (amplifying) refracting medium, if one artificially introduces the additional absorption (amplification), whose value is proportional to the ratio of the wavelength and the effective beam width. It is shown that the analytic model reflects the general features of refracted field at total internal reflection.

全反射法测量液体折射率的一种改进方案

针对棱镜全反射法测量液体折射率时存在的色散现象,将原先的钠灯或汞灯光源替换为激光器,并使用摄像头观察消光现象,排除了复色光谱线对实验测量的干扰。使用改进后的装置测量了不同液体在不同光波长下的折射率。结果表明,测量值与标称值基本吻合,相对不确定度在0.1%以内。改进后的实验方法操作方便、准确度高,有进一步的推广应用价值。

基于光的反射和折射原理的自动水位控制

本文设计了一种基于光的反射和折射原理的自动水位控制饮水机。该装置以光的反射和折射为基础,利用Arduino UNO单片机作为控制中枢,实现自动识别不同高度的杯型,自动开始注水,并当水面到达距离杯沿1cm处自动停止注水的控制。该装置创新地利用了光的折射原理,在激光发射器和激光接收器位置不变的情况下,通过改变两个三棱镜的角度,实现对不同杯型水位的非接触性精确控制;该装置体积小巧并且简单易于操作,可以实现自动注水和自动停止注水的完全非接触性操作,减少传统饮水机由于接触性带来的交叉感染,并且该装置成本低廉,具有较强的应用潜力。

Measurement of absolute phase shift on reflection of thin films using white-light spectral interferometry

A novel method to measure the absolute phase shift on reflection of thin film is presented utilizing a white-light interferometer in spectral domain. By applying Fourier transformation to the recorded spectral interference signal, we retrieve the spectral phase function Ф, which is induced by three parts： the path length difference in air L, the effective thickness of slightly dispersive cube beam splitter Teff and the nonlinear phase function due to multi-reflection of the thin film structure. We utilize the fact that the overall optical path difference （OPD） is linearly dependent on the refractive index of the beam splitter to determine both L and Teff. The spectral phase shift on reflection of thin film structure can be obtained by subtracting these two parts from Ф. We show theoretically and experimentally that our new method can provide a simple and fast solution in calculating the absolute spectral phase function of optical thin films, while still maintaining high accuracy.

Optical fiber hydrogen sensor based on light reflection and a palladium-sliver thin film

Thin alloy films of palladium(Pd) and silver(Ag) are deposited onto glass substrates via the direct current(DC) magnetron technique.The hydrogen sensor probe consists of optical fiber bundle and Pd/Ag optical thin film.when the sensor is exposed to hydrogen,the refractive index of Pd/Ag optical thin layer will diminish and cause attenuation changes of the reflective light.It is observed that the thickness of Pd/Ag alloy layer can affect the hydrogen sensor signal.Under different substrate temperatures,several Pd/Ag samples are coated with different thicknesses of Pd/Ag alloy,and the results of a hydrogen sensor based on reflective light from the Pd/Ag alloy thin film are discussed.

基于全反射的透明液体浓度测量装置设计

结合光学原理,利用全反射,设计测量透明液体浓度的实验装置.由亚克力板容器盛装待测液体,研究激光在液体中发生全反射时的光路参数,通过测量两个长度尺寸,计算得到透明液体的折射率,基于透明液体折射率与浓度之间的线性关系,进而得到其浓度.蔗糖溶液和NaCl溶液的测量数据结果表明,折射率的相对误差在0.4%以内,浓度的绝对误差在0.7%以内.该实验装置具有结构简单、操作简便、测量精度高、成本低廉、现象明显等优点.

利用光子晶体实现位相延迟的讨论

为了设计制造新型的位相延迟器,利用1维光子晶体的特性,在折射率为1.52的玻璃上,镀制了由硫化锌(ZnS)与冰晶石(Na 3AlF 6)构成的多周期二次元一维光子晶体,进行了数值模拟计算及理论分析。结果表明,在带隙范围内,1维光子晶体的等效折射率是虚等效折射率;在斜入射时,带隙内的p光和s光的反射光各自位相增加,出现位相延迟,其偏振态发生改变,由线偏振光变为椭圆(圆)偏振光;在发生全反射时,光疏媒质的等效折射率是虚等效折射率;反射光出现位相增加,产生位相延迟,其偏振态发生改变,由线偏振光变为椭圆(圆)偏振光。该延迟器可以改变光的传播方向,改变偏振态的位相,克服了薄膜λ/4波片的缺陷。

光滑表面光反射的影响因素分析

涂层和基底构成了一个多层介质体系,建立分层介质体系的电磁反射模型,引入等效相对介电常数来考察其折射指数并简单分析了色散特性可能带来的影响,重点考察了典型光滑表面的光反射特征,分析了涂层材料折射指数和厚度变化对表面总反射率的影响。相关方法和结论对后续开展一般性涂层光散射分析具有基础性作用。

菱体型消色差延迟器的优化设计

通过对菱体型延迟器件进行优化设计,能够改善其消色差性。根据光在介质表面全反射时发生相变这一原理,分析了一个具有3个全内反射面的菱体型延迟器件,得出了相位延迟δ与全内反射角θ和相位延迟δ与介质折射率n的关系。通过对δ与θ和δ与n的关系分析,显示了扩大材料选择范围的可行性。结果表明,较大的全内反射角的选择有利于改善延迟器件的消色差性。

菱体型相位延迟器对入射角灵敏性的研究

为了清楚地了解菱体型消色差λ/4相位延迟器对入射角i变化的灵敏性随折射率n变化的规律,利用全反射相变公式详细推导出器件对入射角i变化的灵敏性与折射率n的关系式,并做出了理论曲线。可见,随着折射率n的增加,器件对入射角i的变化更加灵敏。结果表明,设计器件时应尽量避免选择高折射率材料。在分析相位延迟量的测量误差时,这个应用也是很有价值的。

在1341.4 nm激光波长对生物组织折射率的测量(英文)

根据全反射原理 ,设计一个由准直宽光束和双棱镜构成的测量装置用于测量生物组织的折射率 .在波长 632 .8nm通过对几个样品测量 ,证明该方法用于测量生物组织的折射率具有可靠、精确和简单易行的特点 .第一次测得了某些生物组织在 134 1.4nm的折射率 ,也为在 134 1.4nm激光波长测量人体组织的折射率提供了一种有效的方法 .

用全反射法测冰醋酸和酒精的折射率

为了研究冰醋酸溶液和酒精溶液的折射率与体积分数的关系,采用全反射的方法测量了不同体积分数的冰醋酸溶液与酒精溶液的折射率,得到了溶液折射率与体积分数的关系曲线。结果表明,冰醋酸水溶液和酒精水溶液的折射率与体积分数均不存在简单的线性关系,而是呈现出类抛物线型的变化关系。开始体积分数随折射率的增大而增大,但在某一中间体积分数处折射率有一最大值,即冰醋酸在体积分数为0.90附近存在最大折射率,酒精在体积分数为0.80附近存在最大折射率。这一结果对于全面认识溶液折射率与体积分数的关系是有帮助的。

基于线偏振光反射率测量介质折射率的研究

研究线偏振光的振幅反射率与介质折射率的关系,提出一种测量介质材料折射率的方法。文中从菲涅耳公式出发,推导出各向同性介质的线偏振光反射率与折射率的关系式,给出基于线偏振光反射率测定介质折射率的原理。设计实验方案,在不同入射角情况,定出线偏振光p方向和s方向两种线偏振光在玻璃表面的反射率,得到线偏振光振幅反射率随入射角变化的实验曲线。依此实验数据得出材料的折射率。结果表明,测出的介质材料的折射率与理论值相符,所采取的测定方案可行。

生物组织光学折射率

就生物组织折射率的意义进行了论述，引入一个表观的具有平均意义的参量作为生物组织折射率用于描述光在不同组织分界面上的行为以及光在组织内传播的时间特性；提出了测量生物组织折射率的前提条件和几种新的测量方法并评价了这些方法的优劣性；接着，给出了典型组织折射率在不同环境条件下的测量结果，同时进行了分析和讨论，形成的结论可以对生物组织折射率性质有初步的认识。

一种精确测量波导参数的方法──M线光谱法

本文根据棱镜耦合器内的全反射原理，利用Ｍ线光谱法精确地测量了质子交换ＬＴ波导的衬底和波导模式的有效折射率，借助于ＩＷＫＢ法计算出了波导的折射率的分布，并采用Ｆｅｒｍｉ公式拟合得到波导的表面折射率，其测量精度可达１０￣（－４）量级。