对杂散光测试材料要求的探讨

从分光光度计杂散光测试原理出发,对我国目前在用的几种杂散光测试材料特性进行了分析。通过实验验证,指出了其中的不合理处,并提出了对杂散光测试材料特性的基本要求。 ,     

杂散光及其对分光光度测量的影响

通常情况下,杂散光对分光光度测量的影响是微弱的,因而容易被忽视。在大学仪器分析课程中,对杂散光问题也只作简单介绍。因此,学生在教学实验和后来的工作实践中,对杂     

建立统一的紫外、可见分光光度标准装置的探讨

介绍由低压石英汞灯、镨钕滤光片、透射比标准滤光片、杂散光滤光片等组成标准装置开展紫外、可见分光光度计的检定问题     

建立统一的紫外,可发光光度标准装置的探讨

介绍由低压石英汞灯、错钕滤光片、透射比标准滤光片、杂散光滤光片等组成标准装置开展紫外、可见分光光度计的检定问题。     

略论UV-VISS的可靠性

概述了杂散光(Straylight)、噪声(Noise)、化学因素、电子学等方面对紫外可见分光光度计(UV-VISS)可靠性的影响.同时从元器件的研制、测试方法的研究等方面,讨论了保证UV-VISS可靠性的有关问题.     

用于测定痕量荧光化合物的高效液相色谱化学发光检测法

化学发光法用於高效液相色谱以其优异的高灵敏度而日益受到重视,近年来得到了很大的发展。与荧光检测器相比,这种检测器设备较为简单便宜。由於不需要外光源系统,消除了杂散光及因光源发光不稳定而导致的波动,从而降低了噪声,提高了信噪比。     

流动注射化学发光联用技术及其应用

自Ruzicka和Hansen于1975年提出流动注射分析(FIA)以来,随着其发展和普及,出现了FIA仪器和常规仪器联用的组合式FlA仪器。近年来,由于化学发光(CL)的迅速发展,一些新的联用技术已逐趋成熟,FIA-CL分析即是一例。 CL分析法由于不需要外光源系统,消除了杂散光及因光源发光不稳定而导致的波动,从而降低了噪声,提高了     

学龄前视力低常儿童散光眼分布特征分析

目的分析学龄前视力低常儿童散光眼分布特征,全面探究其散光类型、分布以及矫正情况,旨意为相关研究人员提供理论依据。方法选择2016年1月至2016年12月温州医科大学附属眼视光医院收治的912例学龄前视力低常者(1 730眼)为研究对象,实施散瞳验光,分析统计学结果。结果单眼散光者94例,占10.3%。双眼散光者818例,占89.7%。对称性散光者710例,占86.6%,不对称散光者108例,占13.2%。顺规散光1 646眼,占95.1%,逆规散光64眼,占3.7%,斜轴散光20眼,占1.2%。矫正视力在0.9以上者共计412眼,占23.8%。0.8以下共计1 318眼,占76.2%。在该部分群体中,远视性散光共计1 042眼,近视散光共计30眼。混合散光共计246眼。复性远视散光1188眼,占68.7%,复性近视散光38眼,占2.2%。单纯近视散光6眼,占0.4%,单纯远视散光204眼,占11.79%。混合散光294眼,占17.0%。0.50 D~1.00 D占31.7%,1.25 D~2.00 D占46.4%,2.25 D~3.00 D占15.6%,3.25 D~4.00 D占4.9%,4.25 D~5.00 D占1.3%。5.25 D以上占0.2%。结论在学龄前视力低常群体中,双眼散光为常见疾病类型,其中以复性远视散光为主。散光程度一般在3.00 D以下,轴向分布以顺规散光为主。重度散光为引发弱视的主要因素,因此对于视力低常学龄前儿童,应当做好早期视力筛查,以便尽早矫正散光,恢复正常视力。     

塞曼原子吸收校正曲线的实验和探讨

塞曼效应用于原子吸收背景校正后,许多作者研究了其校正曲线的“翻转”(roll over)现象。也有作者对大量元素的曲线“翻转”作了实验研究,并对此作了理论解释,在解释中还考虑到分析线精细结构和超精细结构的影响。然而这些实验和讨论都忽略了杂散光来源和自吸等因素对校正曲线形状的复杂影响。本文仅就横向恒定磁场偏振分离调制方式商品ZAA仪器(CPMPM)中校正曲线的形状作进一步的研究和解析。     

光谱透射比标准物质的研究

研制了紫外、可见、近红外光谱区通用光谱透射比较标准物质。以高纯熔融石英为基片材料，镍铬合金的镀膜材料，采用双光楔对称光胶结构以消除同色杂散光的影响，对镀膜进行光胶处理以保证膜层的强度、稳定性及光学中性，采用高精度分光光度测量装置作为定值手段的以保证准确的定值，设计定位保护架以消除多次反射误差。该光度标准适用的光谱范围的200-2600nm，光谱透射比定值不确定度为0.5%。     

Stray light effects in Zeeman atomic absorption spectrometry

A transverse Zeeman atomic absorption spectrometer has been modeled using a polychromatic, optical calculus simulation software program. The models were found to be realistic and greatly facilitated the study of the effects of various Zeeman spectrometer parameters and their interactions. The behavior of the Zeeman spectrometer calibration curves, in the presence of three different types of stray light, was modeled. From the initial results, it seems most likely that the major stray light source in real Zeeman experiments is due to polychromaticity of the light source, even when the source profile is relatively narrow in spectral bandwidth.     

Laser microdensitometer for spectrographical measurements

A linear microdensitometer was designed for wide range optical density measurements. A reduced stray light level and an extension of the linear measuring range were achieved by reducing the size of the sampled area isolated from the de-magnified image of the preslit and the use of laser illumination. Display of the spectrum was maintained by incorporating a second beam using an incandescent lamp.Owing to the very effective control of stray and scattered light, the laser microdensitometer proved to be the ultimate solution for the evaluation of photographically recorded spectra.     

Effect of Stray Light on Characteristic Mass in Zeeman Graphite Furnace Atomic Absorption Spectrometry

The characteristic mass (m₀), the effective stray light (α), the Zeeman rollover absorbance (A_r), and the Zeeman sensitivity ratio (R) were studied systematically as a function of lamp current and slit width. The effective stray light, α, was considered to be the sum of all effects that either are different sources of stray light or behave like stray light. Mathematical expressions are presented to describe the relationships between m₀, R, α, and A_r. The characteristic mass, m₀ is directly related to the effective stray light and the Zeeman sensitivity ratio. R. The Zeeman rollover absorbance, A_r, is a quantitative measure of the effective stray light. By taking α and R into account, a stable characteristic mass value, ^cm₀ was obtained for copper, silver, thallium, and chromium for different lamp currents and slit widths. This gave rise to a new concept "the corrected characteristic mass." Without correction for these effects, the relative standard deviations (RSDs) of measured characteristic mass values, m₀, were 8% for Cr, 19% for Tl, 20% for Cu, and 26% for Ag, for a wide range of currents and/or slit widths. After correction for the effects of rs and R, the corrected characteristic masses, ^cm₀, were stable with an RSD of only 4% for Cu, Cr, and TI, and 7% for Ag.     

Single fiber absorption measurements for remote detection of 2,4,6-trinitrotoluene

Single fiber optical measurements have been used to follow changes in the color of an initially clear poly(vinyl chloride) membrane as it reacts with aqueous 2,4,6-trinitrotoluene (TNT) to form a colored product that absorbs strongly at 500 nm. Attempts to make this measurement via the effect of the colored product on the emission spectrum of a fluorophore incorporated into the PVC membrane were unsuccessful. However, single fiber absorption measurements were successful. Refractive index matching to reduce stray light and a reflector behind the membrane to increase the reflected intensity were essential to keep the stray light levels small relative to the signal of interest. To compensate for drift, the reflected intensity at 500 nm is measured relative to the reflected intensity at 824 nm, a wavelength at which intensity is not affected by color formation in the membrane. The rate at which the ratio of reflected intensity at 824 nm to that at 500 nm increases is a function of TNT concentration. It is estimated that TNT levels as low as 0.10 mg 1^?1 can be determined by this technique.     

Reduced UV light scattering in PDMS microfluidic devices

Microfluidic devices which consist of polydimethylsiloxane (PDMS) are used extensively for the production of polymer microparticles through the use of droplet templating and on-chip photopolymerization. However, in existing methods, spatial confinement of the photochemical droplet solidification is impaired by UV light scattering inside the PDMS elastomer. We present a technique to load PDMS microfluidic devices with a fluorescent dye that absorbs the scattered UV light and shifts it to longer wavelengths. By this means, the stray light is no longer harmful, and UV exposure can be limited to a desired region on the microfluidic chip.     

An apparatus for measuring Thomson scattering from an inductively coupled plasma

An experimental arrangement is presented which has been proven capable of measuring Thomson scattering from an inductively coupled plasma (ICP). This system has been shown to reject stray light to a sufficient extent that useful scattering signals can be measured as near as 0.3 nm from the incident laser wavelength. In this paper, design considerations are discussed and a viable experimental system is described. Preliminary Thomson scattering results are presented.     

A LABORATORY INVESTIGATION OF TWO ULTRAVIOLET SPECTRORADIOMETERS

Abstract— Spectral measurements of the solar UV irradiance at the earth's surface depend critically on the characteristics of the spectroradiometers and the procedures used in their calibration. Two UV spectroradiometers were subjected to a series of laboratory tests to investigate which factors were most significant in limiting the reliability of the absolute irradiance measurements. Three independent standards of spectral irradiance were scanned by both instruments under a range of bench conditions. The results were consistent to within about 3%, most of the uncertainty being due to scattered light in the laboratory. An UV laser was used to determine the slit function of each spectrometer and the influence of internal stray light. Significant departures from the ideal cosine and azimuth responses were measured by a xenon lamp. Both spectroradiometers were kept indoors throughout the experiments. The relevance of these laboratory results is discussed with respect to the task of measuring solar UV radiation in the field.     

Two-color excitation system for fluorescence detection in DNA sequencing by capillary array electrophoresis

Two computer-controlled galvanometer scanners are adapted for two-dimensional step scanning across a 96-capillary array for laser-induced fluorescence detection. 488 nm and 514 nm laser lines from the same Ar(+) laser were alternately coupled for two-color excitation in each capillary. The signal at a single photomultiplier tube is temporally sorted to distinguish among the capillaries and the excitation wavelengths. Based on the differences in absorption spectra for the dyes, the peak-height ratios in the 488 nm and 514 nm excitation electropherograms were used for peak identification for multiplexed capillary electrophoresis. Successful base calling for 24-capillary DNA sequencing was achieved to 450 bp with 99% accuracy. Advantages include the efficient utilization of light due to the high duty-cycle of step scan, good detection performance due to the reduction of stray light, ruggedness due to the small mass of the galvanometer mirror, low cost due to the simplicity of components and flexibility due to the independent paths for excitation and emission.