IF 3.2 3区工程技术

Metrologia Pub Date : 2026-08-01 Epub Date: 2026-08-05 DOI: 10.1088/1681-7575/ae81ba

Klaus N Quelhas, Richmond S Wang, Andrea Peruzzi, Weston L Tew

{"title":"Realizations of the triple points of carbon dioxide and sulfur hexafluoride-ITS-90 temperature determinations and interpolations.","authors":"Klaus N Quelhas, Richmond S Wang, Andrea Peruzzi, Weston L Tew","doi":"10.1088/1681-7575/ae81ba","DOIUrl":"10.1088/1681-7575/ae81ba","url":null,"abstract":"The triple points of carbon dioxide (TP CO2) and sulfur hexafluoride (TP SF6) have been studied over the last decade as alternative fixed points to the triple point of mercury (TP Hg, 234.3156 K) on the International Temperature Scale of 1990 (ITS-90). NIST has been developing TP CO2 and TP SF6 cells to be employed as drop-in replacements for TP Hg cells for calibrations of standard platinum resistance thermometers (SPRTs). This work presents the results of the assessment of new immersion-type CO2 and SF6 triple point cells built at NIST and the results of their use in ITS-90 calibrations of long-stem SPRTs. It was demonstrated that a very well-controlled realization technique can result in measurements of the triple points of CO2 and SF6 within 25 μK and 75 μK of reproducibility, respectively, with estimated temperatures of 216.591 21(15) K and 223.556 22(33) K for F= 1, respectively. The large volume expansion of CO2 and SF6 upon melting in large immersion cells is responsible for a progressive head correction that increases the realization slopes of the triple points of CO2 and SF6 by 0.1 mK and 0.46 mK, respectively. Calibrations of two SPRTs on different ITS-90 subranges using either TP Hg, TP CO2 or TP SF6 cells showed that the interpolated temperatures using either triple point agreed within their realization uncertainties. These results demonstrate that both fixed points can be used as alternatives for the Hg TP in a future revision of the ITS-90.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"63 4","pages":"045004"},"PeriodicalIF":3.2,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13439574/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148679054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Low-Frequency Calibration of Accelerometers by Rotation in the Gravitational Field at NIST. NIST在重力场中旋转加速度计的低频校准。

IF 3.2 3区工程技术

Metrologia Pub Date : 2026-05-07 DOI: 10.1088/1681-7575/ae5193

Jared H Strait, Richard A Allen, Michael Gaitan

引用次数: 0

Companion guide to the revised technical guidelines for reliable dc measurements of the quantized Hall resistance for graphene-based devices. 石墨烯基器件量化霍尔电阻可靠直流测量修订技术导则的配套指南。

IF 3.2 3区工程技术

Metrologia Pub Date : 2026-01-01 DOI: 10.1088/1681-7575/ae6c09

Albert F Rigosi, Hansjörg Scherer, Mathieu Taupin, Luca Callegaro, Hans He, Susmit Kumar, Ali Eichenberger, Mattias Kruskopf, Yanfei Yang, Martina Marzano, Stephen Giblin, Sergiy Rozhko, Takehiko Oe, Dong-Hun Chae, Pierre Gournay

{"title":"Companion guide to the revised technical guidelines for reliable dc measurements of the quantized Hall resistance for graphene-based devices.","authors":"Albert F Rigosi, Hansjörg Scherer, Mathieu Taupin, Luca Callegaro, Hans He, Susmit Kumar, Ali Eichenberger, Mattias Kruskopf, Yanfei Yang, Martina Marzano, Stephen Giblin, Sergiy Rozhko, Takehiko Oe, Dong-Hun Chae, Pierre Gournay","doi":"10.1088/1681-7575/ae6c09","DOIUrl":"10.1088/1681-7575/ae6c09","url":null,"abstract":"This companion guide revises and expands upon the established technical guidelines for reliable direct current measurements of the quantized Hall resistance, adapting them to the unique characteristics of epitaxial graphene. Graphene has emerged as a viable alternative to traditional Gallium Arsenide heterostructures for metrological applications due to its relaxed operating conditions. These less demanding requirements facilitate the use of low-cost, compact cryomagnet platforms, which is expected to broaden the deployment of primary resistance standards to National Metrology Institutes and other laboratories with limited resources. The guide explores the specific challenges and considerations of epitaxial graphene devices, including aspects of device choice, cooling and handling, contact resistance, conditions of quantization, and general measurements of the quantized Hall resistance. The presented details should assist those seeking to conduct rigorous characterization procedures to verify device integrity, ultimately contributing to a global effort to formally accept graphene-based devices as reliable primary resistance standards.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"63 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13417957/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148620680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Leveraging the revised International System of Units: torque from the fundamental constants. 利用修订后的国际单位制：来自基本常数的扭矩。

IF 3.2 3区工程技术

Metrologia Pub Date : 2025-09-17 DOI: 10.1088/1681-7575/ae029a

Zane Comden, Stephan Schlamminger, Frank Seifert, Kumar Arumugam, Chandra B Shahi, David B Newell, Leon S Chao

引用次数: 0

Primary activity measurement of an Am-241 solution using microgram inkjet gravimetry and decay energy spectrometry. 用微米喷墨重量法和衰变能谱法测定Am-241溶液的初级活度。

IF 3.2 3区工程技术

Metrologia Pub Date : 2025-07-17 DOI: 10.1088/1681-7575/adecaa

Ryan P Fitzgerald, Bradley K Alpert, Denis E Bergeron, Max Carlson, Richard Essex, Sean Jollota, Kelsey Morgan, Shin Muramoto, Svetlana Nour, Galen O'Neil, Daniel R Schmidt, Gordon Shaw, Daniel Swetz, R Michael Verkouteren

{"title":"Primary activity measurement of an Am-241 solution using microgram inkjet gravimetry and decay energy spectrometry.","authors":"Ryan P Fitzgerald, Bradley K Alpert, Denis E Bergeron, Max Carlson, Richard Essex, Sean Jollota, Kelsey Morgan, Shin Muramoto, Svetlana Nour, Galen O'Neil, Daniel R Schmidt, Gordon Shaw, Daniel Swetz, R Michael Verkouteren","doi":"10.1088/1681-7575/adecaa","DOIUrl":"10.1088/1681-7575/adecaa","url":null,"abstract":"We demonstrate a method for radionuclide assay that is spectroscopic with 100 % counting efficiency for alpha decay. Advancing both cryogenic decay energy spectrometry (DES) and drop-on-demand inkjet metrology, a solution of Am-241 was assayed for massic activity (of order 100 kBq/g) with a relative combined standard uncertainty less than 1 %. We implement live-timed counting, spectroscopic analysis, validation by liquid scintillation (LS) counting, and confirmation of quantitative solution transfer. Experimental DES spectra are well modeled with a Monte Carlo simulation. The model was further used to simulate Pu-238 and Pu-240 impurities, calculate detection limits, and demonstrate the potential for tracer-free multi-nuclide analysis, which will be valuable for new cancer therapeutics based on decay chains, Standard Reference Materials (SRMs) containing impurities, and more widely in nuclear energy, environmental monitoring, security, and forensics.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"62 4","pages":""},"PeriodicalIF":3.2,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13108511/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147775953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Uncertainty of the measurement of the frequency dependence of four-terminal pair capacitance with a four-channel vector network analyzer. 四通道矢量网络分析仪测量四端对电容频率依赖性的不确定度。

IF 2.4 3区工程技术

Metrologia Pub Date : 2025-03-31 DOI: 10.1088/1681-7575/adc39e

Stephan Schlamminger, Andrew Koffman, Yicheng Wang

引用次数: 0

Calibrating laser Doppler anemometers utilizing an optical chopper. 利用光学斩波器校准激光多普勒风速计。

IF 2.1 3区工程技术

Metrologia Pub Date : 2025-01-01 DOI: 10.1088/1681-7575/adac64

Christopher J Crowley, Iosif I Shinder, Michael R Moldover, Joey T Boyd, B James Filla, Aaron N Johnson

引用次数: 0

Conversion of a piston-cylinder dimensional dataset to the effective area of a mechanical pressure generator. 将活塞-气缸尺寸数据集转换为机械压力发生器的有效面积。

IF 2.4 3区工程技术

Metrologia Pub Date : 2024-12-01 DOI: 10.1088/1681-7575/ad77db

Patrick F Egan, Eric S Stanfield, John R Stoup, Christopher W Meyer

{"title":"Conversion of a piston-cylinder dimensional dataset to the effective area of a mechanical pressure generator.","authors":"Patrick F Egan, Eric S Stanfield, John R Stoup, Christopher W Meyer","doi":"10.1088/1681-7575/ad77db","DOIUrl":"10.1088/1681-7575/ad77db","url":null,"abstract":"Recent developments in diameter metrology at NIST have improved the dimensional characterization of piston-cylinder assemblies (PCAs) to unprecedented precision. For the newest generation of PCAs, the standard uncertainty in the measurement of the outer diameter is 12 nm, while uncertainty in the measurement of the inner diameter is 14 nm. With a high-accuracy dimensional dataset in hand, the task of determining the pressure generated by a specific PCA is reduced to converting the diameter (and straightness and roundness) to an effective area (and distortion coefficient). The details on how this was performed for the artifact PCA2062 are described. PCA2062 was dimensioned in 2017 and 2020; the area repeated within <math><mrow><mn>0.2</mn> <mo>×</mo> <msup><mn>10</mn> <mrow><mo>-</mo> <mn>6</mn></mrow> </msup> <mo>⋅</mo> <msub><mi>A</mi> <mn>0</mn></msub> </mrow> </math> . The calculation produced estimates of fall rate and rotation decay that agreed with experimental observations within 12 %. The fall rate is proportional to the square of the gap width; therefore, the agreement between calculation and measurement validates the dimensional estimate of the gap width within (36 ± 42) nm, where the 42 nm standard uncertainty is governed by the present state of flow theory. The piston gage model is buttressed by three comparison tests against a laser barometer, which support a view that PCA2062 is linear and reproducible within 0.2 μPa Pa-1. Finally, an estimate of uncertainty in the effective area of a dimensioned artifact is provided: as expected, the diameter measurement is the main culprit, but there are open questions regarding the flow model that preclude an accurate evaluation of the distortion coefficient. For the 530 kPa operating range of PCA2062, distortion is not a significant problem, but the effect would be dominant in assemblies operating at 1 MPa and above.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"61 6","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11494611/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142503477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Evaluating the structural and predictive validity of a derivational morphology task with struggling adult readers. 对有困难的成年读者进行派生词形态任务的结构和预测有效性评估。

IF 2.4 3区工程技术

Metrologia Pub Date : 2024-10-01 Epub Date: 2023-07-14 DOI: 10.1007/s11145-023-10462-y

Gal Kaldes, Elizabeth L Tighe

{"title":"Evaluating the structural and predictive validity of a derivational morphology task with struggling adult readers.","authors":"Gal Kaldes, Elizabeth L Tighe","doi":"10.1007/s11145-023-10462-y","DOIUrl":"10.1007/s11145-023-10462-y","url":null,"abstract":"The purpose of this study was to (a) examine the underlying assessment structure of the Derivational Morphology Task (DMORPH) and (b) investigate the relation of the DMORPH to vocabulary and reading comprehension outcomes with a sample of struggling adult readers. Specifically, participants included 218 struggling adult readers enrolled in adult literacy classes. We used item-level analyses to evaluate the underlying structure of the DMORPH. Items with phonological (e.g., \"music\" to \"musician\") and non-phonological transformations (\"teach\" to \"teacher\") were examined in relation to adult literacy students' vocabulary and reading comprehension skills. A bifactor model was the best fit to the data, suggesting that the DMORPH measured a single factor of derivational morphological awareness with some variation due to phonological and non-phonological change items. Follow-up analyses revealed that the DMORPH can essentially be considered unidimensional, which justified the use of a single scoring system for the DMORPH with adult literacy students. However, after controlling for word reading and phonological awareness, the phonological change items uniquely predicted vocabulary knowledge and reading comprehension, whereas the non-phonological change items were not significant. The results support the structural validity of the DMORPH and the need to use both phonological and non-phonological change items with adult literacy students. The present findings also provide insight into potential intervention targets for instructors in adult literacy programs who are interested in improving students' vocabulary and reading comprehension skills.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"55 1","pages":"2101-2126"},"PeriodicalIF":2.4,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11544760/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82768917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A robust time scale for space applications using the student’s t-distribution 使用学生 t 分布的稳健空间应用时间尺度

IF 2.4 3区工程技术

Metrologia Pub Date : 2024-09-15 DOI: 10.1088/1681-7575/ad7606

Hamish McPhee, Jean-Yves Tourneret, David Valat, Jérôme Delporte, Yoan Grégoire and Philippe Paimblanc

{"title":"A robust time scale for space applications using the student’s t-distribution","authors":"Hamish McPhee, Jean-Yves Tourneret, David Valat, Jérôme Delporte, Yoan Grégoire and Philippe Paimblanc","doi":"10.1088/1681-7575/ad7606","DOIUrl":"https://doi.org/10.1088/1681-7575/ad7606","url":null,"abstract":"In this article, the principles of robust estimation are applied to the standard basic time scale equation to obtain a new method of assigning weights to clocks. Specifically, the Student’s t-distribution is introduced as a new statistical model for an ensemble of clocks that are experiencing phase jumps, frequency jumps or anomalies in their measurement links. The proposed robust time scale is designed to mitigate the effects of these anomalies without necessarily identifying them, but through applying a method of robust estimation for the parameters of a Student’s t-distribution. The proposed time scale algorithm using the Student’s t-distribution (ATST) is shown to achieve comparable robustness to phase jumps, frequency jumps, and anomalies in the measurements with respect to the AT1 oracle time scale. The AT1 oracle is a special realization of the AT1 time scale which corrects all anomalies by having prior knowledge of their occurrences. The similar performance of ATST and AT1 oracle suggests that the ATST algorithm is efficient for obtaining robustness with no prior knowledge or detection of the occurrences of anomalies.","PeriodicalId":18444,"journal":{"name":"Metrologia","volume":"31 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2024-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142263943","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}

引用次数: 0

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