煤中水分含量测定仪计量性能校准方法的研究

根据煤中水分含量测定仪的结构组成和工作原理,研究了对仪器计量性能可靠易操作的校准方法。仪器的校准项目包括称量示值误差、称量稳定性、温度偏差、温度波动度、示值误差和测量重复性等6个计量特性指标,并描述了每个指标的校准方法。试验结果表明,该校准方法可操作性强,校准结果有较好的溯源性和可比性,能较好的反映仪器的计量性能。     

灰熔融性测定仪计量校准方法探讨

灰熔融性测定仪用于测定煤的灰熔融性这一重要指标,目前并没有可依据的检定规程或校准规范等技术性文件。本文根据其工作原理和结构组成,研究了可靠且易操作的计量校准方法,分别对其控温性能、测量性能等性能指标进行计量校准,校准结果具有较好的溯源性和可比性。     

倾点测定仪校准方法研究

正不同生产厂家的倾点测定仪性能差异较大,无统一评判标准,仪器质量参差不齐。为保证仪器测量结果的一致性、准确性和溯源性,需要对其进行计量校准。笔者对倾点测定仪的校准进行了探究。一、倾点测定仪的工作原理油品预加热到一定温度后,在规定的浴温下冷却,每隔3℃检查一次油品的流动性,测量油品能够流动的最低温度。仪器的计量性能应符合表1的要求。     

渗透压摩尔浓度测定仪校准方法的研究

渗透压摩尔浓度测定仪检测数据的准确性对药物分析影响很大,建立一套完善的校准方法,定期对渗透压摩尔浓度测定仪进行校准是医药计量工作的当务之急.通过长期的实践摸索,对各种渗透压摩尔浓度测定仪进行了系统的检测和论证,初步建立了一套可靠的校准方法.该方法科学合理,简便易行,各项指标评价结果符合仪器的设计性能及实际检测工作的要求...     

混凝土氯离子含量快速测定仪校准方法研究

正目前,我国还没有相应国家检定规程或校准规范对混凝土氯离子含量快速测定仪进行计量检定或校准,因此,对其校准方法的研究有利于量值溯源和量值传递。选择北京耐久科技仪器有限公司生产的NJCL-H型混凝土氯离子含量快速测定仪作为校准对象。仪器包含电计和电极两部分,分别从电计电位和配套电极两个方向讨论和研究其校准方法。一、电计部分电位示值误差校准混凝土氯离子含量快速测定仪主机部分具有     

电解传感器法-水蒸气透过率测定仪校准方法的研究

本文依据GB/T 21529-2008《塑料薄膜和薄片水蒸气透过率的测定电解传感器法》,主要介绍了一种行之有效的水蒸气透过率测定仪详细校准方法,并对其校准的主要计量特性进行了具体的论述,该研究是在目前尚无国家校准规范的背景下,为电解传感器法-水蒸气透过率测定仪提供了可供参考的校准方法,为计量及仪器使用人员对此类仪器的校准或性能确认提供了可靠的参考。     

基于介电常数法的车用汽油辛烷值测定仪校准探讨

汽油辛烷值是衡量汽油在气缸内抗爆震燃烧能力的一种数字指标,可用辛烷值测定仪快速测量。汽油辛烷值测量结果的准确可靠,既可最大限度实现汽油的动力经济性能,也可提升驾驶安全性。本文探讨了用车用汽油辛烷值标准物质对基于介电常数法的车用汽油辛烷值测定仪进行校准,并对校准结果进行不确定度评定,为仪器测量结果可靠性提供前提保障。     

黄曲霉毒素测定仪的校准技术

为确保黄曲霉毒素测定仪量值的准确可靠,探讨了该类仪器主要计量特性的校准方法。根据该类仪器的工作原理和结构组成,将其校准项目分为干涉滤光片峰值波长误差,吸光度的零点漂移、示值稳定性、示值误差、示值重复性等计量特性指标。以分光光度计和光谱中性滤光片作为标准器可校正以上指标。试验结果表明,该校准方法可操作性强,校准结果有较好的溯源性和可比性。     

离子选择电极法氯离子含量测定仪的校准方法

通过对离子选择电极法氯离子含量测定仪的原理和特点进行研究,采用有证标准物质和温度计等设备作为校准标准,制定了该仪器的校准项目和校准方法,并给出参考的计量性能指标;通过实验验证了校准方法及指标参数的合理性、科学性、可操作性。     

比色法氨氮测定仪校准方法探讨

正比色法氨氮测定仪主要包含实验室氨氮自动分析仪和非自动化的氨氮测定仪,非自动化的氨氮测定仪又分为台式和便携式两种。目前,JJG631-2013 《氨氮自动监测仪检定规程》无法满足比色法氨氮测定仪的计量需求。本文根据仪器的工作原理、结构组成以及主要性能要求,依据现有的技术水平,探讨了一种校准方法,以确保仪器测量结果的准确性和溯源性。     

浅谈余氯分析仪的校准

分析了水中游离氯及总余氯测定方法的现状,从余氯测定仪校准规范的检测对象、量值溯源、方法原理等方面进行了分析探讨,对实际操作中曲线标定、干扰物消除和方法优化提出建议,对计量检定机构对余氯分析仪开展校准工作有一定的指导意义。     

Multivariate calibration and instrument standardization for the rapid detection of diethylene glycol in glycerin by Raman spectroscopy

The transfer of a multivariate calibration model for quantitative determination of diethylene glycol (DEG) contaminant in pharmaceutical-grade glycerin between five portable Raman spectrometers was accomplished using piecewise direct standardization (PDS). The calibration set was developed using a multi-range ternary mixture design with successively reduced impurity concentration ranges. It was found that optimal selection of calibration transfer standards using the Kennard-Stone algorithm also required application of the algorithm to multiple successively reduced impurity concentration ranges. Partial least squares (PLS) calibration models were developed using the calibration set measured independently on each of the five spectrometers. The performance of the models was evaluated based on the root mean square error of prediction (RMSEP), calculated using independent validation samples. An F-test showed that no statistical differences in the variances were observed between models developed on different instruments. Direct cross-instrument prediction without standardization was performed between a single primary instrument and each of the four secondary instruments to evaluate the robustness of the primary instrument calibration model. Significant increases in the RMSEP values for the secondary instruments were observed due to instrument variability. Application of piecewise direct standardization using the optimal calibration transfer subset resulted in the lowest values of RMSEP for the secondary instruments. Using the optimal calibration transfer subset, an optimized calibration model was developed using a subset of the original calibration set, resulting in a DEG detection limit of 0.32% across all five instruments.     

SMPS-3936气溶胶粒径谱仪测试原理及其性能评定

为探索SMPS-3936气溶胶粒径谱仪整体性能的评定及其校准方法,在分析其测试原理的基础上,指出影响其性能的主要因素,然后通过实验的方法对其系统流量和测量粒子粒径的准确度这两项指标进行了研究。结果表明,通过发生标准粒子校准仪器测量颗粒粒径准确度的方法,可以从整体上评价气溶胶粒径谱仪的性能,为该类仪器的性能评定与校准提供参考依据。     

Ground-based zenith sky abundances and in situ gas cross sections for ozone and nitrogen dioxide with the Earth Observing System Aura Ozone Monitoring Instrument

High-accuracy spectral-slit-function calibration measurements, in situ ambient absorption gas cell measurements for ozone and nitrogen dioxide, and ground-based zenith sky measurements with the Earth Observing System Aura Ozone Monitoring Instrument (OMI) flight instrument are reported and the results discussed. For use of high-spectral-resolution gas absorption cross sections from the literature in trace gas retrieval algorithms, accurate determination of the instrument's spectral slit function is essential. Ground-based measurements of the zenith sky provide a geophysical determination of atmospheric trace gas abundances. When compared with other measurements, they can be used to verify the performance of the OMI flight instrument. We show that the approach of using published high-resolution absolute absorption cross sections convolved with accurately calibrated spectral slit functions for OMI compares well with in situ gas absorption cell measurements made with the flight instrument and that use of these convolved cross sections works well for reduction of zenith sky data taken with the OMI flight instrument for ozone and nitrogen dioxide that are retrieved from measured spectra of the zenith sky with the differential optical absorption spectroscopy technique, the same method to be used for the generation of in-flight data products. Finally, it is demonstrated that the spectral stability and signal-to-noise ratio performance of the OMI flight instrument, as determined from preflight component and full instrument tests, are sufficient to meet OMI mission objectives.     

激光测速仪校准技术研究

综述了激光测速仪的现有校准方法,提出了采用模拟目标进行激光测速仪校准的新方法,并根据该原理研建了校准装置.经各种校准方法的比较分析和校准试验验证,说明装置校准范围宽、重复性好、通用性好,可以满足激光测速仪的校准需求.     

Determination of main and minor components of silicon based materials by a combustion with elemental fluorine. Separation of gaseous fluorination products by carrier gas distillation and gas mass spectrometry

For the determination of main and minor components in silicon-based ceramic powders, a decomposition by a combustion with elemental fluorine and separation of the volatile fluorination products by a carrier-gas distillation with a subsequent detection by quadrupole mass spectrometry is described. The necessity and success of the separation step is demonstrated for the determination of boron as a minor constituent in SiC, where the spectral interferences of silicon on the boron signals are decreased considerably. The method developed is shown to be directly applicable to determination of silicon in Si3N4, SiC, and SiO2. The determination of nitrogen in Si3N4 requires additional effort, to separate nitrogen from the excess of fluorine. For the determination of boron, a complete mobilization of BF3 is assured by the presence of an adequate amount of GeF4. Analysis results obtained with different types of calibration show a precision of 30 microg for boron at the milligram-per-gram level and a precision between 0.5 and 2% (m/m) for the main components, silicon and nitrogen. Within these standard deviations, the results agree well with the values expected from the stoichiometry, with the results for silicon and boron obtained by wet chemical decomposition and slurry techniques in combination with ICP-OES and with the results for nitrogen obtained by carrier gas heat extraction.     

Application of the SKYRAD Improved Langley plot method for the in situ calibration of CIMEL Sun-sky photometers

The in situ procedure for determining the solar calibration constants, originally developed for the PREDE Sun-sky radiometers and based on a modified version of the Langley plot, was applied to a CIMEL instrument located in Valencia, Spain, not integrated into AERONET. Taking into account the different mechanical and electronic characteristics of the two radiometers, the method was adapted to the characteristics of the CIMEL instrument. The iterative procedure for the determination of the solar calibration constants was applied to a 3-year data set. The results were compared with the two sets of experimental calibration constants determined during this period using the standard Langley plot method. The agreement was found to be consistent with the experimental errors, and the method can definitely also be used to determine the solar calibration constant for the CIMEL instrument, improving its calibration. The method can be used provided the radiometer is previously calibrated for diffuse radiance using a standard lamp.     

Open air calibration with temperature compensation of a luminescence quenching-based oxygen sensor for portable instrumentation

This report addresses the task of calibrating an optical sensor for oxygen determination. Detailed analyses of the functional dependences from our measurement system results have been carried out with the additional aim of temperature compensation. As a result, an empirical calibration function has been successfully derived for the luminescent quenching-based oxygen sensor included in a self-designed portable instrument. This function also compensates for the temperature influence on the quenching luminescence process in the range from 0 to 45 degrees C. Moreover, the calibration procedure is extremely simple because only a single standard is needed. In fact, the oxygen measurement system can be calibrated with exposure to an open air atmosphere, and therefore, neither laboratory standards nor trained personnel are required. The method has been applied to a set of 11 units of the mentioned sensor (up to 24% oxygen concentration) giving an overall deviation between our calibrated system results and the laboratory standards of 0.3% oxygen concentration (calculated with 95% confidence level). The proposed calibration function has shown itself to be applicable for different sensing film thicknesses and luminophore concentrations using the same fittings parameter. Additionally, this function has been successfully applied to other oxygen dyes. Good agreement has also been found when the performance of the instrument was compared to a commercially available portable instrument based on an electrochemical sensor. We believe that this work could be an interesting finding for spreading the use of optical sensors for atmospheric oxygen determination in commercial measurement equipment for different purposes in confined working atmospheres, such as mines, undergrounds, warehouses, vehicles, and ships.     

Methodology for the independent calibration of Raman backscatter water-vapor lidar systems

We present a method for the independent calibration of Raman backscatter water-vapor lidar systems. Particular attention is given to the resolution of instrumental changes in the short and the long terms. The method reposes on the decomposition of the instrument function, which allows the lidar calibration coefficient to be re-expressed as the product of two terms, one describing the instrumental transmission and detection efficiency and the other describing the wavelength-dependent convolution of the Raman backscatter cross sections with the instrument function. The origins of changes in instrument response necessitate the experimental determination of the system detection efficiency. Two external light sources for calibration are assessed: zenith observation of diffuse sunlight and a xenon arc lamp. The results favor use of the diffuse-sunlight measurement but highlight the need for simultaneous sunphotometer measurements to constrain modeled aerosol optical properties. Quantum mechanical models of the Raman cross sections are described, and errors in determining the cross sections and their convolution with the instrument function are discussed in detail. The calibration coefficients deduced by using the independent method are compared with coefficients deduced from Vaisala H-Humicap radiosonde measurements. These results agree to within current calibration errors (15%, unconstrained aerosol parameters), and a change in calibration coefficient following instrument modification is reproduced satisfactorily. Results from modeling and intercomparison studies are extended to estimate the calibration accuracy and the precision of the diffuse-sunlight method with constrained modeled aerosol parameters. Changes in the calibration coefficient in the short and the long terms should be resolved to 4(6)% and 6(9)%, respectively, which is comparable or better than the precision of existing dependent methods of calibration. The reduction of the absolute calibration error remains an outstanding issue for all calibration methods.