低温辐射计计量比对研究

低温辐射计是迄今为止国际上公认最精确的光辐射功率测量系统,基于探测器的光辐射量值是可溯源的基本量。低温辐射计是目前国际上公认最准确的光辐射功率测量方法,是基于探测器的光辐射量值溯源源头。为验证不同实验室间的低温辐射计测量量值的一致性,由中国计量科学研究院作为主导实验室组织了此次低温辐射计比对,参比实验室包括中国电子科技集团第四十一研究所与西安应用光学研究所。介绍了比对的基本情况与技术方案,分析了比对结果。比对结果表明,各参比实验室相对于比对参考值的测量偏差在±0.02%之内;尽管各实验室使用的低温辐射计的类型不同以及装置存在差异,比对结果证明了各实验室低温辐射计测量的量值具有较好的一致性。     

Analysis of Comparison Data from Acceleration Measurements

The Evaluation Guidelines [1] specify general analysis methods for key comparisons of measurement data where their reasonable application is subject to some preconditions. We discuss a real example of comparison data that can be analyzed in formal accordance with the Guidelines. But we prefer a model-based analysis benefiting from the intrinsic relation of the data. Indeed, this method is founded on the principles of the Guidelines. In our example, the laboratories participating in the key comparison have carried out a series of calibration measurements of a particular accelerometer. The values from this series correspond to the measurements at different excitation frequencies. A physical model describing the frequency dependence is known. The proposed model-based analysis estimates the unknown model parameters taking the values from the series of the laboratories simultaneously into account. If the derived model and the data are consistent, the model function gained represents the reference values. The advantage of the model-based analysis is that we utilize the a priori knowledge we have at our disposal. We obtain better reference values, i.e., the uncertainties associated with the reference values are considerably lower.     

Evaluation of laboratory performance through interlaboratory comparison

This paper reports the performance of the calibration results obtained by 21 laboratories using digital pressure calibrator as an artifact in the pressure range 7–70 MPa. National Physical Laboratory (NPLI), New Delhi has coordinated this programme and also acted as a reference laboratory. The program started in May, 2006 and completed during May, 2008. The comparison was carried out at 10 equally spaced pressure points i.e. 7,14,21,28, 35,42,49,56, 63 and 70 MPa throughout the entire pressure range of 7–70 MPa. The calibration results thus obtained were analyzed as per ISO / IEC GUM document. The 92.7 % measurement results are found in agreement with the results of NPLI. The relative deviations between laboratories values and reference values are well within the 0.05 %for 123 measurement points, 0.1% for 162 measurement points and 0.25% for 177 measurement points. The difference of the laboratories values with reference values are found almost well within the uncertainty band of the reference values at 68.0 % measurement results, within their reported expanded uncertainty band at 81.5% measurement results and within the combined expanded measurement uncertainty band at 92.7 % measurement results. Overall, the results are considered to be reasonably good being the first proficiency testing for most of the participating laboratories.     

EURAMET.T-K7 Key Comparison of Water Triple-Point Cells

The results of a EURAMET key comparison of water triple-point cells (EURAMET.T-K7) are reported. The equipment used, the measuring conditions applied, and the procedures adopted for the water triple-point measurement at the participating laboratories are synthetically presented. The definitions of the national reference for the water triple-point temperature adopted by each laboratory are disclosed. The multiplicity of degrees of equivalence arising for the linking laboratories with respect to the ??mother?? comparison CCT-K7 is discussed in detail.     

Standardisation of pressure measurement using pressure balance as transfer standard

This paper describes the results of the interlaboratory comparison for pressure measurements of 9 laboratories that are accredited by the National Accreditation Board for Testing and Calibration of Laboratories (NABL). The artifact used for the comparison was a pressure balance covering the pressure range (7 to 70) MPa. The primary objective of this comparison was to assess the laboratory’s technical competence to perform measurements and also to assess the compatibility of the results submitted by the laboratories. The comparison began during March 2008 and ended during April 2010. For assigning the reference values, the pilot laboratory (NPLI) carried out 3 calibrations of the transfer standard; the first one at the beginning, the second at the middle and the last one at the end of the programme. The comparison was carried out at 10 pressure points i.e. (7, 10, 15, 20, 25, 30, 40, 50, 60 and 70) MPa throughout the entire pressure range of (7 to 70) MPa. The measurements were carried out by each laboratory with their own resources (personnel, calibration systems, environmental conditions in their installations). The deviations for each laboratory were compared against the reference values and the compatibility of the results was calculated using the normalized error value method. Out of the total 87 measurement results reported, 68 (78.2%) results are found in good agreement with the results of the reference laboratory. The normalized error (E_n) values of 5 laboratories out of the total 9 were found well within ± 1 over the entire pressure range. However, 2 other laboratories had shown good agreement with the reference values except one pressure point each. The E_n values of one of the participating laboratory were found beyond acceptable limits at all measurements points. Another laboratory had acceptable results only at 3 pressure points. The laboratories with unacceptable results have been advised to review their pressure measurement process. The deviations between laboratory values and of the reference values were found well within the uncertainty band of the reference values for 37% measurement results. The relative deviations for 82 measurement results were found well within 0.05%.     

Technical Aspects of Guidelines for the Evaluation of Key Comparison Data

Some of the technical aspects of guidelines for key comparison data evaluation prepared by BIPM Director's Advisory Group on Uncertainties are considered. These guidelines relate to key comparisons based on the measurement of a travelling standard having good short-term stability and stability during transport, in cases where the institutes' measurements are realised independently. They include two procedures for forming a key comparison reference value (KCRV), and the associated uncertainty, and the consequent degrees of equivalence (including the associated uncertainties), in accordance with the Mutual Recognition Arrangement. The basis of the procedures is (a) the representation of the information provided by the participating institutes as probability density functions (pdf), and (b) the estimator (model) used as the KCRV. The calculation of the KCRV and the associated uncertainty and the degrees of equivalence is then undertaken in accordance with the law of propagation of uncertainty, as described in the Guide to the Expression of Uncertainty in Measurement (GUM), or the propagation of distributions, a generalisation of the law of propagation of uncertainty, covered in a supplemental guide to the GUM. Attention is paid to the choice of model, relating it to the conditions that apply to the key comparison. The first procedure is intended for cases where for each institute a Gaussian distribution is assigned to the measurand of which the institute's measurement is an estimate. The weighted mean is used as the model in this case. A consistency test is included to determine whether the model is consistent with the data. If the test is satisfied, the weighted mean is accepted as the KCRV. The second procedure is used in circumstances where (a) not all the pdf's assigned are Gaussian or (b) where the first procedure had previously been applied, the consistency test was not satisfied and there was no opportunity to correct all institutes' data regarded as discrepant. The model in this case is chosen to be a more robust estimator such as the median or another estimator considered appropriate for the particular comparison.     

PMP与CCEM衰减关键比对的链接

APMP 衰减关键比对APMP.EM.RF-K19.CL将比对测量结果与CCEM衰减关键比对进行了链接。在链接计算中,应用加权平均方法计算链接修正值;应用中位数方法剔除链接数据中的统计离群值,并考虑了链接实验室CCEM比对原数据有效性问题。链接计算结果表明链接修正值可靠,评定的不确定度合理。     

Erratum to: Interlaboratory Comparison of Five Standard Weights of Class F2 in Several Romanian Laboratories

This paper reports the results of measurements performed on five standard weights of class F₂, by several metrology laboratories throughout Romania. The comparison began in 2009 and concluded in 2010. Mass Laboratory of National Institute of Metrology (INM) acted as pilot laboratory (PL) and reference laboratory (RL) for the programme. Five standard weights of class F₂ (nominal values: 5?kg, 1?kg, 200?g, 100?g and 10?g) were sent to the participants. The laboratory??s results are presented for each weight, along with the associated uncertainty and the normalized errors of each laboratory, with respect to the INM. The results obtained by the participating laboratories in this comparison can be used to validate the measurement capabilities (in the calibration of weights) claimed/approved under the quality management systems.     

全国非接触式汽车速度计比对的研究

由中国计量科学研究院作为主导实验室的全国非接触式汽车速度计比对于2018年完成。作为机动车测速计量领域的首个固定地点的现场比对,参比实验室29家,其中27家为已建标的省级计量技术机构,全部比对结果为满意。介绍了比对的基本情况、技术方案,研究了比对方法和不确定度来源,提出了测速计量现场比对的特殊性,分析了比对结果。     

甲烷中微量气体标准物质分析方法研究及量值的比对（续二）

建立了甲烷中微量气体标准物质的分析方法和实验条件;考察了该分析方法的不确定度;得出甲烷中微量气体标准物质浓度在（1～50）×10-6（mol/mol）范围内,方法不确定度小于1%的实验结果。实验过程对重量法制备的系列气体标准物质量值进行了分析方法的比对,一致性验证结果在1%内吻合。该项研究成果代表国家最高实验室参与了国际计量委员会组织的CCQM-K66的关键比对,得到了满意的实验结果,获得了国际的等效度。     

甲烷中微量气体标准物质分析方法研究及量值的比对

建立了甲烷中微量气体标准物质的分析方法和实验条件;考察了该分析方法的不确定度;得出甲烷中微量气体标准物质浓度在(1 ～50)×10-6(mol/mol)范围内,方法不确定度小于1％的实验结果.实验过程对重量法制备的系列气体标准物质量值进行了分析方法的比对,一致性验证结果在1％内吻合.该项研究成果代表国家最高实验室参与了...     

甲烷中微量气体标准物质分析方法研究及量值的比对(续一)

建立了甲烷中微量气体标准物质的分析方法和实验条件;考察了该分析方法的不确定度;得出甲烷中微量气体标准物质浓度在(1～ 50)×10-6(mol/mol)范围内,方法不确定度小于1％的实验结果.实验过程对重量法制备的系列气体标准物质量值进行了分析方法的比对,一致性验证结果在1％内吻合.该项研究成果代表国家最高实验室参与了...     

CCT-K7水三相点容器国际关键比对

在国际互认框架内，国家计量标准的国际等效性是通过国际计量委员会（CIPM）的咨询委员会组织的一系列国际关键比对来确定的。温度咨询委员会（CCT）委托国际计量局（BIPM）作为主导实验室组织了由20个国家实验室参加的CCT-K7水三相点容器国际关键比对。比对结果表明：这些国家基准水三相点值在0．171mK范围内一致。此外，为了减小国家实验室复现水三相点的系统差，需要进一步研究同位素组成对水三相点温度的影响以及同位素修正。     

Interlaboratory Comparison of Five Standard Weights of Class F2 in Several Romanian Laboratories

This paper reports the results of measurements performed on five standard weights of class F₂, by several metrology laboratories throughout Romania. The comparison began in 2009 and concluded in 2010, Mass Laboratory of National Institute of Metrology (INM) acted as pilot laboratory (PL) and reference laboratory (RL) for the programme. Five standard weights of class F₂ (nominal values: 5?kg, 1?kg, 200?g, 100?g and 10?g) were sent to the participants. The laboratory??s results are presented for each weight, along with the associated uncertainty declared and the normalized errors of each laboratory, with respect to the INM. The results obtained by the participating laboratories in this theme can be used to validate the measurement capabilities (in the calibration of weights) declared under the quality management systems.     

Isotopic Correction of Water-Triple-Point Cells at NMIJ

The twenty-one participating laboratories in the international key comparison of water-triple-point cells (CCT-K7) can be classified into three groups: two laboratories that corrected the effect of the isotopic composition of water, four laboratories that had information on the isotopic composition but did not correct the effect, and the remaining laboratories that had no information. There were significant differences in the realized national standard for the triple point of water (TPW) between those laboratories that applied the isotopic correction and those that did not. The isotopic correction is now considered essential for the triple point of water. Since the National Metrology Institute of Japan (NMIJ) did not apply the isotopic correction and estimated large uncertainties at the time of the CCT-K7 comparison, we subsequently developed new cells for the TPW to improve the reliability and to reduce the uncertainty of the realization as a national reference. The isotopic compositions of seven cells were analyzed, and a chemical impurity analysis of one cell was performed. The good consistency among seven cells was shown in the results obtained when the isotopic correction was applied to the realized temperatures measured experimentally. The expanded uncertainty of the new national reference of NMIJ is estimated to be 49 μK (k = 2), and as a result of this improvement, the expanded uncertainty for calibrating a water-triple-point cell is 80 μK. The previous reference of NMIJ, reported in CCT-K7 to have an expanded uncertainty of 302 μK, is 42 μK lower than the new one. The new reference value is within the uncertainty of the previous national reference, and the new uncertainty is completely covered by the previous uncertainty. Furthermore, the new reference of NMIJ shows good agreement with the national references of the six laboratories able to apply isotopic corrects to their results for CCT-K7. These facts confirm the validity and the linkage to the CCT-K7 of both the previous and the new national references of NMIJ.     

Intercomparison of the Realization of the ITS-90 at the Freezing Points of Al and Ag among European NMIs

The EUROMET.T-K4 comparison is the regional extension of CCT-K4, an intercomparison of the realizations of the freezing points of Al (660.323°C) and Ag (961.78°C). The intercomparison was organized in four loops. Long-stem standard platinum resistance thermometers (SPRTs) were used as traveling standards: 25 Ω thermometers to be used only at the Al freezing point and two high-temperature standard platinum resistance thermometers (HTSPRTs) to be used only at the Ag freezing point in each loop. Parallel to the measurements with thermometers, the pilots and sub-pilots organized an internal intercomparison using an Ag fixed-point cell. Most HTSPRTs showed a strong drift which is mainly due to mechanical stress and poisoning of the sensor by impurities. This drift can be partially compensated by a correction based on Matthiessen’s rule. An evaluation of the data taking into account both HTSPRTs in each loop, the linkage of the sub-pilots by measurements at the Ag freezing point, and a possible compensation according to Matthiessens’s rule, allows calculation of the results of the participants’ measurements at the Ag freezing point. The results of the participating laboratories are summarized, and proposals for key comparison reference values and linking of the results to CCT-K3 and CCT-K4 are presented.     

Comparison of Meteorological Service Calibration Laboratories in Southeastern Europe

Interlaboratory comparisons serve as tools for assessment of measurement results performed by calibration laboratories in the relevant field of measurement. They are effective means to demonstrate technical competence of the participant and are used as a technical base for accreditation. However, in the network of meteorological services calibration laboratories, comparisons among laboratories are still rare. Some laboratories are still not evaluating measurement uncertainty, thus causing problems when comparing meteorological data from different countries. The Environmental Agency of the Republic of Slovenia (EARS), serving in the frame of the World Meteorological Organization as a Regional Instrument Centre, has organized a round-robin comparison of calibration laboratories of meteorological services in the southeastern part of Europe using instruments for temperature, relative humidity, and barometric pressure. Each participant laboratory had to calibrate a set of instruments at defined calibration points, to evaluate the measurement uncertainty (if possible), and to report the results. EARS RIC invited the National Hydrometeorological Services in the southeastern part of Europe to take part in the intercomparison. In addition, the Laboratory of Metrology and Quality (MIRS/UL-FE/LMK), which holds the Slovenian national standard for temperature and relative humidity, was also invited to participate in the comparison and in the data analysis. Results from MIRS/UL-FE/LMK and EARS were used to calculate the temperature and humidity comparison reference values, while the EARS results were taken as reference values for barometric pressure.     

铝凝固点及银凝固点容器国际关键比对评述

介绍了国际计量局（BIPM）温度咨询委员会（CCT）关键比对4即铝凝固点及银凝固点容器国际比对。采用固定点容器直接比对的形式进行，共11个国家实验室参加了该项比对，介绍了比对的组织、比对过程、实验方法以及参考值的选取，同时给出了比对结果及比对等效图。     

海水无机成分国际比对CCQM-P111及其聚类分析

对2008年中国计量科学研究院(NIM)实验室应邀参与CCQM-P111 part B海水无机成分量测定过程进行了阐述.数据表明,Na+,Sr2+,Cl-等数据均在不确定度范围内,而且相对扩展不确定度均最小或较小.国际比对结果支持和验证了以往对Na+和Cl-等离子的定值结果,但对Sr2+等尚需关键比对支持.将聚类分析应用于国际比对,尚无类似报道,其综合聚类结果表明,NIM所报数据与参考值最为接近.Mg2+的聚类分析表明,采用中位值评价比对实验室能力的方法在实验室数目少且离群值影响较大时应慎重采用.聚类分析可从另外一个角度对比对数据进行分析,例如综合评价、异常值判定、系统偏差分析等方面.     

Report of the Proficiency Testing in the Pneumatic Pressure Region up to 5 MPa

We report the performance of calibration laboratories in the pneumatic pressure region (0 to 5) MPa through a recently conducted inter-laboratory comparison. Six NABL (National Accreditation Board for Testing and Calibration Laboratories) accredited laboratories participated in the program. The proficiency testing program was organized and piloted by CSIR-National Physical Laboratory. The program started in June 2010 and was completed in October 2011. The artifact used was a high precision pressure dial gauge. The reference values were generated by the pilot laboratory. The deviations for each participating laboratory were estimated against the reference pressure values and the compatibility of the results was calculated using the conventional method. Out of the total measurements made, all but two were found to be in good agreement with the reference values. The normalized error values (E _n) of five laboratories out of the total six were found well within ± 1 over the entire pressure range.