原子吸收光谱仪检测元素的选择性

原子吸收光谱仪是根据被测元素的基态原子对特征辐射的吸收程度进行定量分析的仪器。它能检测多种不同元素的含量。按原子化器的类型不同,可分为火焰原子化器和石墨炉原子化器两种。一般企业大多使用火焰原子化器的原子吸收光谱仪。火焰原子化器检测浓度单位一般是10-6μg/mL,原子吸收光谱仪对铜的检测限是0.02μg/mL。前段时间,我公司使用的两台原子吸收光谱仪(火焰原子化器)测量铅含量时数据有时为正值、有时为负     

时栅位移传感器示值误差测量不确定度分析及评定

时栅位移传感器（或称时栅）作为一种新型的测角传感器,对它的精度评定没有可供直接采用的标准或规范。本文以JJF1059—1999《测量不确定度评定与表示》为依据,以时栅示值误差的校准方法出发,对影响时栅的不确定度因素加以分析,确定了时栅不确定度的评定方法,并根据测量数据对时栅不确定度进行了评定。被校准时栅的不确定度U=0．6”,k=2。     

噪声变送器电流输出声压灵敏度测量结果的不确定度评定

介绍了一种直接测量噪声变送器电流输出声压灵敏度的不确定度评定方法,对频率1000Hz、声压级84. 0dB时的噪声变送器电流输出声压灵敏度的测量不确定度进行评定,得到测量结果的扩展不确定度为0. 0011mA/d B(k=2),为噪声变送器电流输出声压灵敏度的准确校准提供了技术参考。     

覆层厚度测量仪示值误差测量不确定度评定

该文旨在规范覆层厚度测量仪测量不确定度分析与评定工作,确保测量不确定度评定结果的准确可靠。该文运用国际通用不确定度评定方法,建立测量模型,对以标准厚度片作为标准器校准覆层厚度测量仪示值误差进行了测量不确定度评定,并分析其不确定度分量,以期为广大测量人员提供不确定度分析参考依据。     

原子荧光光度计测量砷元素检出限测量不确定度分析与评定

原子荧光光度计测定砷、锑、硒、汞等元素具有灵敏度高、检出限低、精密度高等优点,在国家标准规范方法中应用较多,文章主要依据JJG 939—2009 《原子荧光光度计检定规程》对测定砷元素检出限建立数学模型、分析不确定来源、评定不确定度分量、最终合成得到原子荧光光度计测量砷元素检出限标准不确定度UAs=0.016 ng(k=2),对于检定和校准原子荧光光度计工作有着重要参考和指导意义。     

超声波测厚仪示值误差测量不确定度评定

本文旨在规范超声波测厚仪示值误差测量不确定度分析与评定工作,确保测量不确定度评定结果的准确可靠。运用国际通用不确定度评定方法,建立测量模型,对以标准厚度块作为标准器校准超声波测厚仪示值误差进行了测量不确定度评定,并分析其不确定度分量的各个来源。     

电感耦合等离子体发射光谱仪检出限测量结果的不确定度评定

本文依据JJF1059-2012《测量不确定度评定和表示》和JJG 768-2005《发射光谱仪》计量检定规程,以电感耦合等离子体发射光谱仪(ICP)检出限为研究对象建立数学模型,分析空白标准溶液引入的标准不确定度分量、校准曲线斜率引入的标准不确定度对合成不确定度的影响,计算各分量灵敏度系数,并结合实验分析数据,以其作为电感耦合等离子体发射光谱仪检出限测量结果的不确定度评定的重要参考,以确保仪器检定满足规程要求,为计量仪器的溯源传递提供重要保障。     

油料发射光谱仪测量不确定度分析

本文以CD-40润滑油和CD-40在用润滑油为研究对象,通过使用某型油料发射光谱仪分析不同比例的两种润滑油油样,分析了实验数据的线性关系,研究了油料发射光谱仪测量油液中金属Fe元素浓度值的不确定度,并根据各标准不确定度分量得到了测量结果的扩展不确定度：U95=0．61;Veff=6。     

动车组(客车)轴端接地装置弹簧压力试验台测量不确定度评定

本文就动车组(客车)轴端接地装置弹簧压力试验台的不确定度进行评定,通过分析得出,测量重复性、数显式推拉力计的示值误差、分辨力是不确定度的主要来源。分析结果表明,本项目可达到的校准测量能力(CMC)为:U=0. 18N,k=2。     

能量色散X射线荧光仪校准及不确定度评定

该文通过能量色散X射线荧光光谱仪测量RoHS指令规定的检测X射线荧光分析用标准物质,并制作线性回归标准工作曲线,在对ABS工程塑料中Cd、Cr、Hg、Pb等系列元素含量进行测试时,给出仪器测量上述4种特定元素的引用误差及检出限的校准方法,并对仪器引用误差与检出限测量结果的不确定度进行分析与评定。实验结果表明,仪器测定Cd、Cr、Hg、Pb系列元素含量的引用误差均不超过±5%,扩展不确定度U≤4%(k=2),该校准方法在某种程度上为RoHS元素快速检测仪校准提供技术依据,具有一定的借鉴作用。     

Fourier transform atomic absorption flame spectrometry with continuum source excitation

The design and performance of a Fourier transform atomic absorption flame spectrometer (FT-AAS) is presented. A 300-W xenon arc continuum source and a Michelson interferometer are used. A signal to noise disadvantage arising from the multiplex feature of FT-AAS is demonstrated by varying the photon flux at the detector without changing the exciting radiation. A grating is used for dispersion of the radiation before the interferometer to reduce the spectral window at the photomultiplier tube. Detection limits for several elements are generally an order of magnitude poorer than those obtained by continuum atomic absorption methods using echelle-grating spectrometers. Line profiles and absorption spectra, within the region of the spectral window selected by the grating, can be obtained with this method. Standard curves for sodium were constructed to extend the linear calibration range, by using absorbances measured at the absorption maximum and 0.022 nm off-line.     

The potential for using IBP spectrometer with spark ablation of samples at ferrous metallurgy enterprises

On the basis of the results of practical utilization of direct analysis of metal samples with an atomic emission spectrometer with inductively bound plasma (IBP), a comprehensive evaluation of the technique applied is given. Analytical capabilities are compared with chemical methods, with spectral analysis by an atomic emission spectrometer with IBP after sample dissolution and by spark atomic emission spectrometers. The role and the place which the above technique can find in a factory laboratory at metallurgical enterprises are shown.     

Multivariate calibration standardization across instruments for the determination of glucose by Fourier transform near-infrared spectrometry

The transfer of multivariate calibration models is investigated between a primary (A) and two secondary Fourier transform near-infrared (near-IR) spectrometers (B, C). The application studied in this work is the use of bands in the near-IR combination region of 5000-4000 cm(-)(1) to determine physiological levels of glucose in a buffered aqueous matrix containing varying levels of alanine, ascorbate, lactate, triacetin, and urea. The three spectrometers are used to measure 80 samples produced through a randomized experimental design that minimizes correlations between the component concentrations and between the concentrations of glucose and water. Direct standardization (DS), piecewise direct standardization (PDS), and guided model reoptimization (GMR) are evaluated for use in transferring partial least-squares calibration models developed with the spectra of 64 samples from the primary instrument to the prediction of glucose concentrations in 16 prediction samples measured with each secondary spectrometer. The three algorithms are evaluated as a function of the number of standardization samples used in transferring the calibration models. Performance criteria for judging the success of the calibration transfer are established as the standard error of prediction (SEP) for internal calibration models built with the spectra of the 64 calibration samples collected with each secondary spectrometer. These SEP values are 1.51 and 1.14 mM for spectrometers B and C, respectively. When calibration standardization is applied, the GMR algorithm is observed to outperform DS and PDS. With spectrometer C, the calibration transfer is highly successful, producing an SEP value of 1.07 mM. However, an SEP of 2.96 mM indicates unsuccessful calibration standardization with spectrometer B. This failure is attributed to differences in the variance structure of the spectra collected with spectrometers A and B. Diagnostic procedures are presented for use with the GMR algorithm that forecasts the successful calibration transfer with spectrometer C and the unsatisfactory results with spectrometer B.     

Comparison of spectral irradiance standards used to calibrate shortwave radiometers and spectroradiometers

Absolute calibration of spectral shortwave radiometers is usually performed with National Institute of Standards and Technology (NIST) or NIST-traceable incandescent lamps. We compare 18 irradiance standards from NIST and three commercial vendors using the same spectrometer to assess their agreement with our working standard. The NIST procedure is followed for the 1000-W FEL lamps from NIST, Optronics, and EG&G. A modified calibration procedure developed by Li-Cor is followed for their 200-W tungsten-halogen lamps. Results are reproducible from one day to the next to approximately 0.1% using the same spectrometer. Measurements taken four months apart using two similar but different spectrometers were reproducible to 0.5%. The comparisons suggest that even NIST standards may disagree with each other beyond their stated accuracy. Some of the 1000-W commercial lamps agreed with the NIST lamps to within their stated accuracy, but not all. Surprisingly, the lowest-cost lamps from Li-Cor agreed much better with the NIST lamps than their stated accuracy of 4%, typically within 2%. An analysis of errors leads us to conclude that we can transfer the calibration from a standard lamp to a secondary standard lamp with approximately 1% added uncertainty. A field spectrometer was calibrated with a secondary standard, producing a responsivity for the spectrometer that was within 5% of the responsivity obtained by Langley calibration using routine field measurements.     

Estimation of Uncertainty in the Determination of Serum Electrolytes (Na,K, Ca,Mg) by Flame Atomic Absorption Spectroscopy

From a standardized and validated method to quantify serum electrolytes (Na, K, Ca and Mg) by flame atomic absorption spectroscopy, combined relative uncertainty (CRSU) and the percentage of combined relative standard uncertainty (% CRSU) were determined. For this, analytical grade standards were used and later from a certified reference material (NIST2670a). Previously, the sources of uncertainty used in the measurement using the Ishikawa diagram (cause-effect) were established, including mass concentration, calibration curves, volume, reactive targets, certified reference material, dilution and repeatability. Quantification of the metals was performed using the atomic absorption spectroscopy technique employing a Perkin Elmer model 3100 equipment. The values obtained for the CRSU on average are below 0.030 and for the % CRSU on average they are below 3.1%. These results indicate that the uncertainty values are acceptable since they are below the recommended values for these metals.     

分压力质谱计校准装置的性能测试及校准实验

介绍了分压力质谱计校准装置的性能指标,并用分压力质谱计校准装置校准了一台四极质谱计,给出了灵敏度、图样系数、线性、质量刻度、分辨本领等校准结果,还研究了气体之间的相互影响.     

Accurate wavelength calibration method for flat-field grating spectrometers

A portable spectrometer prototype is built to study wavelength calibration for flat-field grating spectrometers. An accurate calibration method called parameter fitting is presented. Both optical and structural parameters of the spectrometer are included in the wavelength calibration model, which accurately describes the relationship between wavelength and pixel position. Along with higher calibration accuracy, the proposed calibration method can provide information about errors in the installation of the optical components, which will be helpful for spectrometer alignment.     

水流环境下温度传感器动态响应测量的不确定度评定

为满足核电快响应温度传感器的复验需要,研制了水流环境下温度传感器动态响应测量装置。分析了测量不确定度的来源,评定了时间常数测量结果的不确定度。通过提出微小时间域内电压示值与时间的线性关系,实现了不确定度由温度向时间参数的传递。对某核级快响应铂热电阻温度传感器的测量结果进行了不确定度评定,其时间常数扩展不确定度U=27ms(k=2)。评定结果表明:示波器光标读取电压和时间的分辨力是不确定度的重要来源,研究结果可为实验测量提供借鉴。     

The EBIT Calorimeter Spectrometer: A New, Permanent User Facility at the LLNL EBIT

The EBIT Calorimeter Spectrometer (ECS) is currently being completed and will be installed at the EBIT facility at the Lawrence Livermore National Laboratory in October 2007. The ECS will replace the smaller XRS/EBIT microcalorimeter spectrometer that has been in almost continuous operation since 2000. The XRS/EBIT was based on a spare laboratory cryostat and an engineering model detector system from the Suzaku/XRS observatory program. The new ECS spectrometer was built to be a low maintenance, high performance implanted silicon microcalorimeter spectrometer with 4 eV resolution at 6 keV, 32 detector channels, 10 μs event timing, and capable of uninterrupted acquisition sessions of over 60 hours at 50 mK. The XRS/EBIT program has been very successful, producing many results on topics such as laboratory astrophysics, atomic physics, nuclear physics, and calibration of the spectrometers for the National Ignition Facility. The ECS spectrometer will continue this work into the future with improved spectral resolution, integration times, and ease-of-use. We designed the ECS instrument with TES detectors in mind by using the same highly successful magnetic shielding as our laboratory TES cryostats. This design will lead to a future TES instrument at the LLNL EBIT. Here we discuss the legacy of the XRS/EBIT program, the performance of the new ECS spectrometer, and plans for a future TES instrument.      

Accurate and precise wavelength calibration for wide bandwidth array spectrometers

Calibrating the wavelength scale of an array spectrometer typically involves measurements of lines at well-known wavelengths from a calibration lamp such as a mercury-argon source. This process is relatively straightforward when the lines are well separated, relative to the bandwidth of the spectrometer. When the spectrometer's bandwidth is large, compared with the distance between calibration wavelengths, it becomes increasingly difficult to accurately locate lines in the calibration spectrum. Even calibrations for instruments with a modest bandwidth of 12 nm can be difficult. Here we present results from a simple approach to improve the accuracy of wavelength calibration for an instrument with a large bandwidth (12 nm, center-to-center pixel spacing 3.3 nm). A monochromator has been used to filter the source so that each calibration line can be measured separately. For ten spectrometers, we were able to achieve accuracy better than 0.12 nm, or 0.09 nm on average; this is less than 3% of the pixel spacing. We anticipate this approach will be useful for improving the accuracy of measurements on array spectrometers and particularly in transferring multivariate calibrations between instruments.