Metrologia最新文献_第10页

A high accuracy reference facility for ongoing comparisons of CO₂ in air standards 用于持续比较空气中二氧化碳标准的高精度参考设施

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Metrologia Pub Date : 2023-11-08 DOI: 10.1088/1681-7575/ad0abe

Joele Viallon, Christopher W Meyer, Philippe Moussay, J W Schmidt, Stephen E Maxwell, Fredrik Arrhen, Robert Wielgosz

{"title":"A high accuracy reference facility for ongoing comparisons of CO<sub>2</sub> in air standards","authors":"Joele Viallon, Christopher W Meyer, Philippe Moussay, J W Schmidt, Stephen E Maxwell, Fredrik Arrhen, Robert Wielgosz","doi":"10.1088/1681-7575/ad0abe","DOIUrl":"https://doi.org/10.1088/1681-7575/ad0abe","url":null,"abstract":"Abstract The design, performance characteristics and validation of a next generation reference facility for CO 2 in air standards based on manometry is presented. Novel attributes of the facility include automated operation, avoidance of significant pressure corrections for measurements on extracted CO 2 , fully characterized trapping efficiencies, and reduced measurement uncertainty. &#xD;Improvements in system performance have been achieved using specific materials, notably Silconert®-treated stainless-steel , providing increased mechanical stability whilst minimizing carbon dioxide adsorption on surfaces, and avoiding use of elastomer O-rings, which would lead to losses of CO 2 . Full automation of the cryogenic extraction process of CO 2 from air has been achieved, avoiding any manual intervention within the temperature stabilized section of the facility, and allowed full characterization and correction for trapping efficiencies and trace water measurement.&#xD;The facility has been validated across the CO 2 in air amount fraction range of (380 to 800) µmol mol −1 using standards with values traceable to the reference value of the CCQM−K120 (2018) comparison. It was demonstrated to operate with a standard measurement uncertainty of 0.09 µmol mol −1 at 400 µmol mol −1 . The automation allows five measurement results per day to be produced with a typical standard deviation of the mean at or below 0.02 µmol mol −1 .&#xD;The facility will be used as a stable reference in the future ongoing BIPM.QM−K2 comparison, to compare consistency of amount fraction values in different CO 2 in air standards. The CO 2 amount fraction in two ensembles of nine BIPM standards covering the same range will also be measured with the facility to provide their SI-traceable values, and further monitored on a longer time scale. Each ensemble will constitute a CO 2 in air scale for comparison with other available scales such as WMO.CO2.X2019 through the BIPM.QM−K5 comparison.&#xD;","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":" 23","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135341420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Small Corrections to 1989 NIST Constant-Volume Gas Thermometry Data 1989年NIST定容气体测温数据的小修正

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Metrologia Pub Date : 2023-11-07 DOI: 10.1088/1681-7575/ad0a35

Allan H Harvey

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Evaluation of long-term robustness of the International System of Reference (SIR) used in radionuclide metrology based on the meta-analysis of its machine-readable database 基于机读数据库元分析的国际参考体系(SIR)在放射性核素计量中的长期稳健性评价

3区工程技术

Metrologia Pub Date : 2023-11-07 DOI: 10.1088/1681-7575/ad0a36

Romain Maximilien Coulon, Carine Michotte, Vincent Gressier

{"title":"Evaluation of long-term robustness of the International System of Reference (SIR) used in radionuclide metrology based on the meta-analysis of its machine-readable database","authors":"Romain Maximilien Coulon, Carine Michotte, Vincent Gressier","doi":"10.1088/1681-7575/ad0a36","DOIUrl":"https://doi.org/10.1088/1681-7575/ad0a36","url":null,"abstract":"Abstract In support of the CIPM MRA, the reference system in radionuclide metrology (SIR) is a unique experimental facility that has been able to provide continuous key comparison results for 72 radionuclides for 46 years. These measurement data are now available in a machine-readable format, which allows statistical analysis of these measurement results to be performed efficiently. Such a meta-analysis was conducted to verify whether or not the accumulated data confirmed the bold assumption made in the 1970s of the long-term robustness of the system over decades of operation. It was notably assumed that variation in the properties of the standard solution to be measured or the choice of the 226 Ra reference source would have no impact on the measurement.&#xD;For the majority of radionuclides measured by the SIR, the non-parametric significance tests of the null hypothesis carried out in this study gave no evidence, at the 95 % confidence level, that the above statement should be reconsidered. However, this meta-analysis revealed a significant impact of solution density in the case of 109 Cd, corroborating previous observations made in the case of 241 Am where the robustness of an ionization chamber with respect to the density variation of the solution does not appear to be perfect.&#xD;The extension of the SIR by a liquid scintillation system is under development. It will improve the robustness of international comparison results for those borderline cases where radionuclides emit only low-energy x-rays or gamma rays (< 100 keV).","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"8 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135480306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Monitoring of the offset between UTC and its prediction broadcast by the GNSS 由全球导航卫星系统监测UTC与其预报广播之间的偏移

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Metrologia Pub Date : 2023-11-06 DOI: 10.1088/1681-7575/ad0562

Pascale Defraigne, Elisa Pinat, Gerard Petit, Frédéric Meynadier

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Determination of Mathematical Expectations of Two Weighting Statistics for Ensemble Time Scales 集合时间尺度两加权统计量数学期望的确定

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Metrologia Pub Date : 2023-10-31 DOI: 10.1088/1681-7575/ad02a0

Yiwei Wu, Siran Liu

{"title":"Determination of Mathematical Expectations of Two Weighting Statistics for Ensemble Time Scales","authors":"Yiwei Wu, Siran Liu","doi":"10.1088/1681-7575/ad02a0","DOIUrl":"https://doi.org/10.1088/1681-7575/ad02a0","url":null,"abstract":"Abstract The Bureau International des Poids et Mesures uses the ALGOS algorithm to generate the Echelle Atomique Libre. The original and new ALGOS weighting algorithms employ two different statistics to calculate the weights, resulting in different experimental phenomena. These two statistics are believed to be the keys to analyzing these experimental phenomena, because the statistical characteristics (e.g. the mathematical expectations and variances) of the statistics completely determine the statistical characteristics of the weights, and subsequently the experimental phenomena. The core work conducted in this study is to derive the analytical expressions of the mathematical expectations of these two statistics under ideal conditions and to validate them empirically. This paper provides a theoretical analysis of these expressions and discusses the relationships between them and the mathematical expectations of the Allan variances. These expressions theoretically reveal the reasons behind the experimental phenomena, especially why hydrogen masers are assigned lower weights in the original ALGOS weighting algorithm but higher weights in the new one. According to the derivation process, these analytical expressions are universally applicable and can also be applied to time-keeping laboratories. In the future, this work can be extended to determine the theoretical statistic and weight performances of different types of frequency standards quantitatively for time-keeping laboratories under both ideal and non-ideal conditions, providing a theoretical basis for improving the design of ensemble time scale algorithms. In the appendix, a method of obtaining the experimental variances and probability density functions (PDFs) of these two statistics is additionally proposed. The two-sample Kolmogorov–Smirnov test is presented to compare the experimental and theoretical PDFs of an example.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"28 59","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135765044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method 利用有限元法对压力达1500mpa的控制间隙活塞-气缸总成进行特性分析

3区工程技术

Metrologia Pub Date : 2023-10-18 DOI: 10.1088/1681-7575/acfe13

Chunguang Liu, Can Wang, Zhongli Zhang, Zhenghao Lin, Miaolin Feng

{"title":"Characteristic analysis of a controlled-clearance piston-cylinder assembly up to 1500 MPa using a finite element method","authors":"Chunguang Liu, Can Wang, Zhongli Zhang, Zhenghao Lin, Miaolin Feng","doi":"10.1088/1681-7575/acfe13","DOIUrl":"https://doi.org/10.1088/1681-7575/acfe13","url":null,"abstract":"Abstract We utilized numerical methods to analyze the characteristics of the piston-cylinder assembly of a controlled-clearance piston gauge. The piston gauge was able to measure liquid pressure from 100 MPa to 1500 MPa with the relative expanded uncertainty of 0.02% ( k = 3). We established a finite element model to solve the stress and strain of the structural problem. The effective areas were calculated based on Dadson’s formula using the converged solutions of the clearance and the pressure distribution within the distorted piston-cylinder engagement gap that were iteratively determined by the finite element model and a fluid mechanics model with pressure-dependent fluid’s properties. Results were compared to the effective areas calculated by the modified Heydemann–Welch model based on experimental data, and the relative differences were less than 0.02%. We found sharp declines of the clearance and pressure distribution near the exit of the piston-cylinder engagement gap, which may lead to wearing during long-time operation at high pressures. Numerical results indicated non-linear relationship between jacket pressure and the cubic root of piston fall speed, which was traditionally considered as linear. The stall jacket pressure obtained by cubic (instead of linear) fitting extrapolation was found more close to the ones determined directly by the finite element model. Numerical results also found non-linear relationships among jacket pressure, measuring pressure, jacket pressure distortion coefficient.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135824169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Reply to Comment on ‘On the dimension of angles and their units’ 回复关于“论角度的维度及其单位”的评论

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Metrologia Pub Date : 2023-10-18 DOI: 10.1088/1681-7575/ad00bf

Peter J Mohr, Eric Shirley, William D Phillips, Michael Trott

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Furnace Effect for the Re-C Fixed Point Re-C固定点的炉效应

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Metrologia Pub Date : 2023-10-18 DOI: 10.1088/1681-7575/acff74

Boris B Khlevnoy, I Grigoryeva

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A novel radiometric calibration of infrared thermometer 一种新的红外测温仪辐射定标方法

3区工程技术

Metrologia Pub Date : 2023-10-16 DOI: 10.1088/1681-7575/acffcb

Yoshiro Yamada, Subrena Harris, Evangelos Theocharous, Michael Hayes

{"title":"A novel radiometric calibration of infrared thermometer","authors":"Yoshiro Yamada, Subrena Harris, Evangelos Theocharous, Michael Hayes","doi":"10.1088/1681-7575/acffcb","DOIUrl":"https://doi.org/10.1088/1681-7575/acffcb","url":null,"abstract":"Abstract A new temperature calibration scheme was proposed and implemented on the National Physical Laboratory infrared radiometer Absolute Measurements of Blackbody Emitted Radiance (AMBER) operating in the wavelength range from 9 µm to 11 µm and equipped with a cryogenically cooled mercury cadmium telluride detector. The scheme involves measurements of the relative spectral responsivity of the filter radiometer including the spectral transmittance of the window and lens. It requires calibration at two reference temperatures, but does not involve measurement of the zero-radiance signal. The scheme uses a Ga-point blackbody as one reference point, and a variable temperature blackbody source at close to −30 °C with its temperature measured with a standard platinum resistance thermometer as the other. The measured temperature was compared using the variable temperature blackbody as the source against the temperature measured by the standard platinum resistance thermometer and agreement within the uncertainties was confirmed at intermediate temperatures. The scheme has the advantage that it makes full use of the small uncertainty realised by the fixed-point blackbody. The scheme was successfully implemented in an international comparison of sea surface temperature measuring radiometers where AMBER served to provide the reference.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"36 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136078068","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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Development of a coulometry system at the Korea Research Institute of Standards and Science and evaluation of the measurement uncertainty originating from the system 在韩国标准科学研究院开发库仑计系统，并对该系统产生的测量不确定度进行评估

3区工程技术

Metrologia Pub Date : 2023-10-16 DOI: 10.1088/1681-7575/acff75

Kyungmin Jo, Youngran Lim, Kyoung-Seok Lee, Euijin Hwang

{"title":"Development of a coulometry system at the Korea Research Institute of Standards and Science and evaluation of the measurement uncertainty originating from the system","authors":"Kyungmin Jo, Youngran Lim, Kyoung-Seok Lee, Euijin Hwang","doi":"10.1088/1681-7575/acff75","DOIUrl":"https://doi.org/10.1088/1681-7575/acff75","url":null,"abstract":"Abstract Coulometry is used to realize the definition of the mole and enables the direct determination of the purity of high-purity substances that are used as standards for other relative measurements with very small measurement uncertainty. However, despite several studies reporting the development of accurate and precise coulometry systems, there is a lack of detailed description of the system and systematic evaluation of the measurement uncertainty arising from the system. In this study, coulometry systems constructed at the Korea Research Institute of Standards and Science (KRISS) are described in detail and the uncertainties associated with these systems are systematically evaluated using a bottom-up approach. The relative expanded uncertainty resulting from the measurement system for the amount-of-substance content of acid in high-purity potassium hydrogen phthalate is approximately 0.0005%. The performance of the KRISS coulometry systems has been verified through several international comparisons and comparative measurements using certified reference materials.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"279 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136078582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

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