漫透射视觉密度基准中光路调试的数值计算

本文介绍了漫透射视觉密度基准的测量装置,详细论述了该基准装置改造时光路调试中应用的数值计算方法.通过计算,调整了测量光路中各个透镜的几何位置,使计算前后漫透射视觉密度基准装置测量的最大入射光通量有了25%提高,因此降低对整个基准测量装置中澳钨灯光强、测量仪表灵敏度的要求,并可以使测量范围适当加宽.     

漫透射视觉密度计检定中一些问题的探讨

漫透射视觉密度计是用于进行光密度测量的计量仪器。近年来逐渐被印刷制版、工业探伤和电子等行业广泛使用。为配合日渐增多的漫透射视觉密度计检定工作，笔者结合在检定中遇到的一些问题．对JJG920—1996《漫透射视觉密度计》检定规程进行探讨，并提出一些看法和建议。     

漫透射视觉密度计示值误差的测量结果不确定度评定

文章依据JJG920-1996《漫透射视觉密度计检定规程》和JJF1059-1999《测量不确定度评定与表示》对目前常用的漫透射视觉密度计进行了示值误差的不确定度评定。     

视觉漫透射密度基准的研究

建立了以光纤半球发射器（HEWOF）为特征的视觉漫透射密度基准。特性化测量表明,其几何与光谱条件符合国际标准ISO 5的规定。合成不确定度为0.0015 (0相似文献   

亮度工作基准自动控制测量系统和透射式标准亮度源的研制

本文介绍了亮度工作基准自动控制测量系统的硬件、软件设计和透射式亮度源的研制。并给出了用该系统进行实测的结果，测量结果表明透射式亮度源给出的亮度值与漫反射工作基准亮度源给出的亮度值的偏差小于0．2％，亮度工作基准装置十分稳定。     

表面粗糙度国际比对自动测量系统关键技术研究

基于中国计量科学研究院的表面粗糙度基准计量装置,开展了视觉定位系统、自动操作系统和多自由度位移系统的研究,从而实现依据国际比对协议规定流程的自动化测量。实验验证表明：该系统可有效实现表面粗糙度的自动化测量,满足国际比对的要求。在对国际比对规定的表面粗糙度标准器的测量实验中,该系统的自动定位测量的重复性为4.2 nm,相比于手动定位测量提高了2.6倍,有效地减少了测量过程中引入的人为误差。     

手持式激光测距仪校准装置及方法的研究

本文提出一种手持式激光测距仪的校准装置及校准方法,使激光经过光路折叠后的反射光平均功率高于测距仪的接收阈值,通过计算测量不确定度,该校准装置满足测距仪的溯源要求。     

小负荷布氏硬度基准装置系统

在静重式硬度基准中实现试验力的自动控制;采用光栅测量技术使压痕测量达到了最高精度等级;给出压痕测量中目视瞄准误差计算方法.根据计量基准的特殊性,从技术方案、具体结构等方面上,确保小负荷硬度基准装置具有计量性能稳定和能长期正常运行的特点.     

光电比较仪(或高温计)系统非线性测量装置

本系统地介绍了新研制的光电比较仪（或高温计）系统非线性测量装置。新装置采用双光源单光路设计,具有独立于被测对象和不失真的特点。利用该装置对基准光电比较仪和标准光电高温计进行了系统实验,测量不确定度达到０．０１％。利用该装置测量的数据已应用于国际计量局（ＢＩＰＭ）和亚太计量规划组织（ＡＰＭＰ）主办的国际比对中。     

一种新型大尺寸长度校准装置的研制

介绍了一种新型的大尺寸长度校准装置,该装置解决了激光干涉仪等高精度大尺寸长度测量仪器的实验室校准与溯源问题.通过采用三路相干光进行测长,根据两辅助光路与主光路的测长偏差计算阿贝角,实现了阿贝误差的实时补偿.利用标准双频激光干涉仪测试了阿贝误差的补偿精度,35 m测量范围内的比对误差小于±3μm.测量精度达到了单光路同轴测量的水平.     

CMOS/CCD矩阵改进投影仪系统

机械工业中准确度高的微小零件采用投影仪进行测量，传统投影仪受瞄准、计算等人的因素影响引入误差，测量准确度受到影响，本文通过对投影仪测量光路和准确度分析，对CMOS／CCD光电成像原理进行分析。采用CMOS／CCD矩阵成像技术改进传统投影仪，并对改进后投影仪原理、参数进行了分析对比，对改造后的光路、性能、与计算机的接口、数控技术连接和经济性能等技术参数与传统投影仪进行对比，从中可以看出其改进后的优越性。     

光栅分振幅光偏振测量系统的研制

使用一个既能产生反射光衍射又能产生透射光衍射的特殊金属光栅作为分光器,研制一种新颖的高速光波偏振态测量系统。它没有使用转动光学部件或调制器,而是将金属光栅产生的四条1级衍射光的光强线性地转换为电信号,通过定标方法得到系统的非奇异的仪器矩阵,然后通过线性运算得到入射光的待测Stokes矢量。该系统结构紧凑、安装方便,可用作实时偏振测量术和椭偏测量术中的偏振态探测器。     

Elastic light-scattering measurements of single biological cells in an optical trap

We have developed an instrument for determination of the angular light scattering of beads and biological cells. The instrument uses radiation pressure for levitation of particles inside a cuvette. The setup consists of two 780-nm diode lasers in a vertical double-beam trapping configuration. In the horizontal direction a weakly focused 633-nm probe beam is used to illuminate the trapped particle. One can detect scattered light over the range of from - 150 to 150 deg with an angular resolution of 0.9 deg using an avalanche photodiode. With this setup light scattering from polystyrene beads was measured, and the obtained scattering patterns were compared with theoretical scattering patterns from Lorenz-Mie theory. The results show that the setup is stable, gives reproducible patterns, and qualitatively agrees with the calculations. Trapping of biological cells is more difficult than trapping of beads, because smaller forces result from smaller refractive indices. We present an angular scattering pattern measured from a human lymphocyte measured from 20 to 60 deg.     

异形粒子测量中粒子有序排列问题的研究

由前向衍射图样可以测量粒子尺寸，但是难于获得关于粒子的全部信息，文中在反向散射理论分析的基础上提出了一种能精确测量红细胞几何尺寸和表面凹陷深度的测量仪器，并说明了被测粒子有序排列的方法及意义。     

Applications of the normal-incidence rotating-sample ellipsometer to high- and low-spatial-frequency gratings

The normal-incidence rotating-sample ellipsometer is an instrument that can be used to characterize grating surfaces from the measured ratio ρof complex reflection coefficients r(y)/r(x) of light polarized perpendicular and parallel to the grating groove direction. Experimental results at different wavelengths for different gratings with spatial frequencies from 150 to 5880 grooves/mm are presented. The groove depth of the 5880-grooves/mm gold-coated grating can be estimated from the measured ρ and rigorous grating theory.     

Two-colour Dynamic Light Scattering

Abstract

The design, alignment and operation of improved two-colour dynamic light scattering equipment which effectively suppresses multiple scattering and allows the study of the Brownian dynamics of optically turbid samples is described. The technique operates by cross-correlating scattered light of two different colours. With the appropriate scattering geometry, only singly scattered light contributes to the time-dependent part of the measured intensity cross-correlation function thus allowing straightforward interpretation of the data. To demonstrate the performance of the instrument we have studied various colloidal suspensions. Although dilute enough that free diffusion of the particles can be assumed, the samples ranged from quite transparent to distinctly turbid. We have confirmed that the measured cross-correlation functions accurately reflect only single scattering even in the presence of strong multiple scattering.     

Optical Techniques for Studying Stray Light in Spectrophotometers

In spectrophotometers the term ‘stray light’ is used to refer to the minute amount of unwanted light having wavelengths outside the narrow band isolated by the optical system. The effect of stray light is to reduce the accuracy of the instrument and in some cases to restrict the wavelength range over which the instrument may be used. The paper describes an optical method by which the stray light transmission of a monochromator may be determined for various wavelengths. If the particular instrument studied is found to show stray light behaviour of a type which varies continuously with wavelength, a simple technique can be applied for assessing the errors that will occur with any given sample. The relative importance of near-stray and far-stray light is discussed.     

光散射式数字粉尘测试仪的标定及其应用

环境粉尘浓度的测定一般使用滤膜称重方法测得,该方法费时费力,且不能得到瞬时粉尘浓度的变化。由于光散射式数字式粉尘测试仪性能稳定、灵敏度高,测量方便而广泛的应用于各类测尘应用。文中介绍了光散射式数字粉尘测试仪各项指标的具体标定方法,并结合实际应用,总结了使用过程中应注意的事项。     

批量光电二极管弱光光敏特性测试仪

针对光照度小于101x的弱光使用环境,提出并设计了一种批量光电二极管弱光光敏特性测试仪。仪器包括可调弱光光源、照度均匀化装置、批量光电二极管固定板、多通道转换开关、微电流放大电路、环境照度监测通道、数据采集及微机接口电路和相关配套软件。仪器的核心为自行研制的光照度在0．01-101x范围内无级可调的弱光光源。实际应用中,在21x照度下,光电二极管弱光光电流一般为12．2-15．6nA,只有少数光电流低于10nA;因此,该仪器可用来进行光电二极管的定量筛选。     

Particle extinction measured at ambient conditions with differential optical absorption spectroscopy. 1. system setup and characterization

We describe an instrument for measuring the particle extinction coefficient at ambient conditions in the spectral range from 270 to 1000 nm. It is based on a differential optical absorption spectroscopy (DOAS) system, which was originally used for measuring trace-gas concentrations of atmospheric absorbers in the ultraviolet-visible wavelength range. One obtains the particle extinction spectrum by measuring the total atmospheric extinction and subtracting trace-gas absorption and Rayleigh scattering. The instrument consists of two nested Newton-type telescopes, which are simultaneously used for emitting and detecting light, and two arrays of retroreflectors at the ends of the two light paths. The design of this new instrument solves crucial problems usually encountered in the design of such instruments. The telescope is actively repositioned during the measurement cycle. Particle extinction is simultaneously measured at several wavelengths by the use of two grating spectrometers. Optical turbulence causes lateral movement of the spot of light in the receiver telescope. Monitoring of the return signals with a diode permits correction for this effect. Phase-sensitive detection efficiently suppresses background signals from the atmosphere as well as from the instrument itself. The performance of the instrument was tested during a measurement period of 3 months from January to March 2000. The instrument ran without significant interruption during that period. A mean accuracy of 0.032 km(-1) was found for the extinction coefficient for an 11-day period in March.