• Metrologia (IF 3.447) Pub Date : 2020-05-25
Andrea Prato, Fabrizio Mazzoleni and Alessandro Schiavi

Traceability of digital sensors is a metrological challenge, as well as a present priority, as stated within the emerging metrology requirements for the future in the Strategy 2017 to 2027 document of the Consultative Committee for Acoustics, Ultrasound, and Vibration of BIPM. From this perspective, in this paper, a calibration system for 3-axis digital MEMS accelerometers is described, in order to

更新日期：2020-05-25
• Metrologia (IF 3.447) Pub Date : 2020-05-25
D R White and P M C Rourke

The thermal metrology community is considering revising the International Temperature Scale of 1990 (ITS-90), motivated by the opportunity to improve the thermodynamic accuracy, reproducibility, and ease of use of the scale, as well as health and safety concerns with the use of mercury in the current scale. This paper considers the mathematical structure of the standard platinum resistance thermometer

更新日期：2020-05-25
• Metrologia (IF 3.447) Pub Date : 2020-05-25
Marco Pizzocaro, Filippo Bregolin, Piero Barbieri, Benjamin Rauf, Filippo Levi and Davide Calonico

We report the absolute frequency measurement of the unperturbed optical clock transition 1 S 0 – 3 P 0 in 171 Yb performed with an optical lattice frequency standard. Traceability to the International System of Units is provided by a link to International Atomic Time. The measurement result is 518 295 836 590 863.61(13) Hz with a relative standard uncertainty of ##IMG## [http://ej.iop.org/images/0

更新日期：2020-05-25
• Metrologia (IF 3.447) Pub Date : 2020-05-25
Yong-Gyoo Kim and Sunghun Kim

Two pure Ni cells for thermocouple calibration were fabricated in alumina crucibles with different internal structures to investigate their melting and freezing behaviors. One of the produced crucibles had a smooth surface, and the other was made with internal circular grooves. The melting and freezing processes of each cell were investigated in 10 melting/freezing cycles using a type B thermocouple

更新日期：2020-05-25
• Metrologia (IF 3.447) Pub Date : 2020-05-25
Piotr Ablewski, Marcin Bober and Michał Zawada

We report the results of measurements of the total hemispherical emissivity coefficients of the most popular vacuum compatible materials used in designs of optical atomic clocks. The experimental vacuum test chamber was designed to precisely quantify the heat transfer between the material’s samples and a calibrated plate that serves as a thermometer. The temperatures of vacuum chamber’s internal surfaces

更新日期：2020-05-25
• Metrologia (IF 3.447) Pub Date : 2020-05-25
Leon Chao, Frank Seifert, Darine Haddad, Jon Pratt, David Newell and Stephan Schlamminger

A tabletop-sized Kibble balance (KIBB-g1) designed to directly realize mass at the gram-level range with uncertainties on the order of parts in 10 6 has been developed at the National Institute of Standards and Technology (NIST). The masses of a nominally 5 g and 1 g weight were determined with ##IMG## [http://ej.iop.org/images/0026-1394/57/3/035014/metab507dieqn001.gif] standard uncertainties of 9

更新日期：2020-05-25
• Metrologia (IF 3.447) Pub Date : 2020-05-17
T A B Milhomem, Z M D Soares, G P Ripper, J P Ayala, G M Guevara, F A Serrano, A Solano, R P Wagner and P Hanes

This document is the Final Report of the Inter-American Metrology System supplementary comparison on pistonphone calibration SIM.AUV.A-S2. Seven national metrology institutes participated on this comparison: CENAM/Mexico, INACAL/Peru, INMETRO/Brazil, INTI/Argentina, LACOMET/Costa Rica, NIST/USA and NRC/Canada and INMETRO was the pilot institute responsible for its coordination. One pistonphone was

更新日期：2020-05-17
• Metrologia (IF 3.447) Pub Date : 2020-05-06
A Germak, C Kuzu, C Origlia and E Pelit

This report describes a bilateral EURAMET supplementary comparison on Rockwell hardness scales of two national metrology institutes of Italy and Turkey, INRiM and UME, respectively. The pilot laboratory is INRiM in the comparison where three sets of hardness reference blocks for the Rockwell hardness scales of HRA, HRBW and HRC were used. Each set of blocks consists of four hardness reference blocks

更新日期：2020-05-06
• Metrologia (IF 3.447) Pub Date : 2020-05-05
Gregor Hülsen, Julian Gröbner, Alkis Bais, Mario Blumthaler, Henri Diémoz, David Bolsée, Ana Diaz, Ilias Fountoulakis, Erik Naranen, Josef Schreder, Facta Stefania and José Manuel Vilaplana Guerrero

In 2017, PMOD/WRC organised the solar ultraviolet broadband radiometer comparison campaign UVC-II . All 75 participating instruments from all over the world were characterised in the laboratory of the World Calibration Center for UV (WCCUV) and calibrated outdoors relative to the Qasume reference spectroradiometer. After a three month calibration period, all devices were returned to their owners, accompanied

更新日期：2020-05-05
• Metrologia (IF 3.447) Pub Date : 2020-05-05
Yu-Jie Tan, Miao-Miao Zhao, Pan-Pan Wang, Ya-Jie Wang, Yao-Yao Xu, Xiao-Chun Duan, Cheng-Gang Shao and Zhong-Kun Hu

Since the double-loop atom interferometer consisting of Raman ##IMG## [http://ej.iop.org/images/0026-1394/57/3/035006/metab7174ieqn1.gif] {${\frac{\pi }{2}\!-\!\pi\!-\!\pi\!-\!\frac{\pi }{2}}$} four-pulse sequences can eliminate the dependence of the interferometric phase shift on the atomic initial velocity, it is widely used for rotation measurements. However, our research shows that by coupling

更新日期：2020-05-05
• Metrologia (IF 3.447) Pub Date : 2020-05-05
Toshiaki Asakai

Analyses of chloride ions, and oxyanions of chlorine named hypochlorite, chlorite, chlorate and perchlorate ions, are of interest especially in the fields of controlling water and food qualities. Some of them do not exist as a certified reference material characterized by a metrologically valid procedure, and the lack of the standards currently creates problems with the instrumental analyses. This

更新日期：2020-05-05
• Metrologia (IF 3.447) Pub Date : 2020-05-05
Qiang Liu, Liang Xing, Sicheng Yan, Liangliang Lv and Zhaoyang Liu

In this paper, the sensing characteristics of a photonic crystal fiber (PCF) Sagnac interferometer based on flat-phase birefringence, zero-group birefringence and the Vernier effect have been studied. The temperature-sensitive liquid is filled into the air holes of the PCF. We realize flat-phase birefringence, by which the sensitivity can reach 4.9 nm/°C and 3.5 nm/°C. We find a new phenomenon in that

更新日期：2020-05-05
• Metrologia (IF 3.447) Pub Date : 2020-05-04
P Gournay, B Rolland, D -H Chae and W -S Kim

The ongoing on-site comparison BIPM.EM-K12 is part of the BIPM programme implemented to verify the international coherence of the primary resistance standards. It allows National Metrology Institutes (NMIs) to validate their implementations of the quantum Hall effect (QHE) for dc resistance traceability by comparison to the reference maintained at the BIPM. The realization of the ohm from the QHE-based

更新日期：2020-05-04
• Metrologia (IF 3.447) Pub Date : 2020-05-04
C Kessler, D T Burns, E Mainegra-Hing, H Shen and M R McEwen

A key comparison has been made between the air-kerma standards of the NRC and the BIPM in mammography x ray beams. The results show the standards to be in agreement at the level of the combined standard uncertainty of 3.2 parts in 10 3 . The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. == Main text To reach the main text

更新日期：2020-05-04
• Metrologia (IF 3.447) Pub Date : 2020-04-30
C Michotte, S Courte, M Nonis, M W van Rooy, M J van Staden and J Lubbe

Since 1989, 6 national metrology institutes (NMI) have submitted 7 samples of known activity of 166m Ho to the International Reference System (SIR) for activity comparison at the Bureau International des Poids et Mesures (BIPM), with comparison identifier BIPM.RI(II)-K1.Ho-166m. The values of the activity submitted were between about 70 kBq and 470 kBq. The key comparison reference value (KCRV) has

更新日期：2020-04-30
• Metrologia (IF 3.447) Pub Date : 2020-04-30
P Gournay, B Rolland, Y Lu and J Zhao

The ongoing on-site comparison BIPM.EM-K12 is part of the BIPM programme implemented to verify the international coherence of the primary resistance standards. It allows National Metrology Institutes (NMIs) to validate their implementations of the quantum Hall effect (QHE) for dc resistance traceability by comparison to the reference maintained at the BIPM. The realization of the ohm from the QHE-based

更新日期：2020-04-30
• Metrologia (IF 3.447) Pub Date : 2020-04-26
S Sembian and M Liverts

While conventional shock tubes have a distinct advantage in dynamic calibration methods due to their inherent capability to generate pressure pulses of desired amplitude and fast rise time, they are limited to the lower levels of the pressure amplitude realization range (≤7 MPa). With the increasing need for a traceable dynamic calibration standard across wider pressure ranges, a novel technique using

更新日期：2020-04-26
• Metrologia (IF 3.447) Pub Date : 2020-04-26
Scott Beattie, Bin Jian, John Alcock, Marina Gertsvolf, Rich Hendricks, Krzysztof Szymaniec and Kurt Gibble

We report the first accuracy evaluation of NRC-FCs2, an atomic fountain clock developed at the National Research Council Canada. The short term stability at high atomic density is 1.1 × 10 −13 at 1 second of averaging time. The typical overall fractional type B uncertainty is 2.3 × 10 −16 . GNSS-based frequency comparisons of NRC-FCs2 with the SI second, as reported by the BIPM over fourteen months

更新日期：2020-04-26
• Metrologia (IF 3.447) Pub Date : 2020-04-26
Romain Coulon, Ryszard Broda, Philippe Cassette, Sammy Courte, Simon Jerome, Steven Judge, Karsten Kossert, Haoran Liu, Carine Michotte and Manuel Nonis

The international reference system for radioactivity relies on stable instrumentation for comparing primary standards of radioactivity; these instruments enable national metrology institutes to demonstrate the equivalence of their primary standards. The international bureau of weights and measures (BIPM) holds two such instruments for gamma-ray emitting radionuclides, and is working with the POLATOM

更新日期：2020-04-26
• Metrologia (IF 3.447) Pub Date : 2020-04-20
In-Mook Choi, Sam-Yong Woo, John Man, Mohamad Aldammad, Wladimir Sabuga, Yue Jin, Nguyen Nam Thang, Gwo-Jen Wu, Chris Sutton, Momoko Kojima, Tawat Changpan, Chan Tak Kin and Renanta Hayu

This report describes the results of a key comparison of pneumatic pressure standards which was carried out at fourteen National Metrology Institutes (NMIs: NMIA, NSCL, PTB, NIM, VMI, CMS/ITRI, MSL, NMIJ/AIST, NMC A*STAR, NIMT, SCL, NIS, RCM-LIPI and KRISS) during the period of February 2010 to July 2012 within the framework of the Asia-Pacific Metrology Programme (APMP) in order to determine their

更新日期：2020-04-24
• Metrologia (IF 3.447) Pub Date : 2020-04-19
B Khlevnoy, O Tarasova, D Scums, T Gorshkova, E Ivashin, M Krempasky, A Kupko, N Vyrodova and E Woolliams

This report gives the results of the COOMET.PR-K3 comparison of luminous intensity. Five laboratories took part in the comparison. COOMET.PR-K3 was piloted by Belarusian State Institute of Metrology (BelGIM). The linkage to KCRV was provided through the participation of the All-Russian Research Institute for Optical and Physical measurement (VNIIOFI) and Slovak Institute of Metrology (SMU). Other participants

更新日期：2020-04-24
• Metrologia (IF 3.447) Pub Date : 2020-04-19
J J Galvan, J C Torres-Guzman, J A Arias and I D Betancur

A Regional Metrology Organization (RMO) key comparison on the calibration of a reference torque wrench was carried out between the Centro Nacional de Metrologia (CENAM, Mexico) and the Instituto Nacional de Metrologia (INM, Colombia), between September 2017 and October 2017. The results of this comparison are reported here, along with descriptions of torque standards used by CENAM and INM, and the

更新日期：2020-04-24
• Metrologia (IF 3.447) Pub Date : 2020-04-19
A M Sadek, Elsa Batisa, Souiyam Samira, Prince Tawiah, Thomas Mautjana, Peter T Molefe, Munyaradzi Mubaiwa, Given Kalonga, Vida Kirenga Rusimbi, Dominic O Ondoro, Onekalit James Bond and Solomon Assefa

An inter-comparison in the calibration of micropipette was conducted among 12 different National Metrology Institutes between 2014 and 2016. Three 100 μL micropipettes were supplied as transfer artifacts. However, one of the three micropipettes did not fulfil the stability assessment criterion and therefore it was excluded from the inter-comparison. The other two micro pipettes were transferred among

更新日期：2020-04-24
• Metrologia (IF 3.447) Pub Date : 2020-04-19
B Rolland, M Stock, S W Chua, K H Lim and E Tan

This report gives the result of a bilateral comparison of resistance between the NMC A*STAR (Singapore) and the BIPM carried out in 2018-2019. Two 1 Ω and two 10 kΩ travelling standards belonging to the BIPM were used. The comparison was carried out with an 'A-B-A' pattern of measurements; the standards were measured first at the BIPM for a period of about two months, then for a period of about one

更新日期：2020-04-24
• Metrologia (IF 3.447) Pub Date : 2020-03-29
Yoshi Ohno, Teresa Goodman, Peter Blattner, Janos Schanda, Hiroshi Shitomi, Armin Sperling and Joanne Zwinkels

This document brings together the definitions and the tables of numerical values for photometry already adopted (or recommended) and published, by the Conférence Générale des Poids et Mesures (CGPM), by the Comité International des Poids et Mesures (CIPM), or by the Commission Internationale de l’Eclairage (CIE). This document provides the link between the definition of the candela in the International

更新日期：2020-03-29
• Metrologia (IF 3.447) Pub Date : 2020-03-29
Stéphan Briaudeau, Frédéric Bourson, Olga Kozlova, Mohamed Sadli and Annick Razet

This paper describes a new relative technique developed at LNE-Cnam, for the determination of the thermodynamic temperature of blackbodies without recourse to a radiometric reference. This technique is referred to as the ‘synthetic double wavelength technique’ (SDWT) as it is considered to be a particular case of the ‘double wavelength technique’ (DWT). It offers a new experimental technique for the

更新日期：2020-03-29
• Metrologia (IF 3.447) Pub Date : 2020-03-25
Jonathan V Pearce

Pt and Rh oxide vapour transport is thought to dominate the thermoelectric drift of Pt-Rh thermocouples above about 1200 °C. A simple model is presented which relates the electromotive force (emf) drift rate of Pt-Rh thermoelements to the vapour pressure of Pt and Rh oxides. The model assumes that the evaporation of these oxides gives rise to a continuously changing concentration of Pt and Rh, at different

更新日期：2020-03-25
• Metrologia (IF 3.447) Pub Date : 2020-03-25
Dong Meng, Sun Wenjun, Wu Chengyao, Chen Lian, Li Yali, Guo Meiru, Zhao Lan, Ding Dong, Sun Donghua, Ren Zhengyi, Ma Yafang and Cheng Yongjun

Partial pressure measurement has become indispensable for many applications and contributes to the complete characterization of a vacuum system. In this work, an ultrahigh vacuum (UHV) standard was established for calibrating partial pressure analyzers as a partial pressure standard, and a new method was introduced to generate standard partial pressures, which was named ‘the dynamic expansion method

更新日期：2020-03-25
• Metrologia (IF 3.447) Pub Date : 2020-03-25
Pinrui Shen, Kirk W Madison and James L Booth

We report the realization of the first cold-atom primary standard. This standard is based on a universal law governing quantum diffractive collisions between particles that allows an experimental determination of the velocity averaged total collision cross section, the only parameter required to quantify the pressure or flux of particles given a sensor particle collision rate measurement. Using an

更新日期：2020-03-25
• Metrologia (IF 3.447) Pub Date : 2020-02-28
Bruno Hay, Robert Zarr, Clark Stacey, Nikolay Sokolov, Leonel Lira Cortés, Jintao Zhang, Ulf Hammerschmidt, Jean-Remy Filtz and Alexandre Allard

Seven National Metrology Institutes (NMIs) from France, United States, United Kingdom, Russia, Mexico, China and Germany participated in an inter-laboratory comparison on thermal conductivity measurements by the Guarded Hot Plate method. This action was part of a series of supplementary inter-laboratory comparisons (including infrared spectral emittance and thermal diffusivity) sponsored by the Consultative

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-28
S Alisic, B Gutfeldt, F Beaudoux, M Bezjak, M Coenegrachts, S Davidson, G Grgić, R Hanrahan, J L W A van Geel, S Kacmaz, B Mangutova-Stoilkovska, M Miteva, G Navrozidis, P T Neuvonen, L Nielsen, M Ojanen-Saloranta, D Pantić, A Pärn, G F Popa, L Snopko, I Spohr, P Conceição, M Stock, Cs Vámossy, C Wüthrich, T Žandarova, Z Zelenka, J Zůda and Saud M AlQarni

In order to demonstrate the equivalence in calibration of mass standards among National Metrology Institutes (NMIs) of EURAMET this key comparison (KC) on 1 kg stainless steel mass standards has been carried out under the auspices of EURAMET. The comparison was undertaken with reference to the International Prototype Kilogram (IPK) as the definition of the unit of mass. The overall result shows good

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-28
Koichiro Hattori, Chung-Lin Wu, Nae-Hyung Tak, Ping Yang, Tassanai Sanponpute, Raymond Leung, Pham Thanh Ha and Satoshi Takagi

This report describes the results of first APMP key comparison on Vickers hardness, APMP.M.H-K1b and APMP.M.H-K1c involving Seven member institutes, CMS/ITRI (Chinese Taipei), KRISS (Korea, Republic of), NIM (China), NMIJ/AIST (Japan), NIMT (Thailand), SCL (Hong Kong, China) and VMI (Vietnam). The pilot laboratory was NMIJ/AIST. Three institute, KRISS, NIM and NMIJ/AIST, act as linking institutes to

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-28
C Kessler, D T Burns, P Roger, Wu Jinjie and Wang Peiwei

A first key comparison has been made between the air-kerma standards of the NIM, Republic of China and the BIPM in mammography x-ray beams. The results show the standards to be in agreement at the level of the combined standard uncertainty of 2.8 parts in 10 3 . The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database. == Main

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-25
Harald Müller, Isabelle Caré and Konstantin Popov

The bilateral key comparison between PTB and VNIIM (CCM.FF-K3.2011.1) was performed as direct follow-up of the CIPM air speed key comparison (CCM.FF-K3.2011) which was organized to determine the degree of equivalence of the national standards for air speed covering the range 0.5 m/s to 40 m/s under ambient conditions. An ultrasonic anemometer and a laser Doppler anemometer were used as transfer standards

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-25
Naoki Kuramoto, Lulu Zhang, Shigeki Mizushima, Atsushi Waseda, Sho Okubo, Hajime Inaba, Akira Kurokawa and Kenichi Fujii

To improve the primary density standard of the National Metrology Institute of Japan (NMIJ), the absolute densities of two 1 kg silicon spheres, NMIJ-S4 and NMIJ-S5, were determined by measuring their masses and volumes. The volumes of the two spheres were measured by optical interferometry based on the primary length standard of NMIJ. For the accurate volume determination, the thicknesses of the surface

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-25
Konstantina Vasilatou, Kai Dirscherl, Kenjiro Iida, Hiromu Sakurai, Stefan Horender and Kevin Auderset

We report on an inter-laboratory comparison for the calibration of light-scattering optical particle counters measuring the number concentration of airborne particles in the size range 300 nm–5 µm. This comparison, registered as EURAMET pilot study Nr. 1453, is an important first step towards internationally recognized SI traceability in the measurement of low particle number concentrations encountered

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-25
Dong-Hun Chae, Mun-Seog Kim, Wan-Seop Kim, Takehiko Oe and Nobu-Hisa Kaneko

Accurate measurement of the electric current requires a stable and calculable resistor for an ideal current-to-voltage conversion. However, the temporal resistance drift of a physical resistor is unavoidable, unlike the quantum Hall resistance directly linked to the Planck constant h and the elementary charge e . Lack of an invariant high-resistance leads to a challenge in making small-current measurements

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-25
Joële Viallon, Faraz Idrees, Philippe Moussay, Robert Wielgosz and Friedrich Lagler

As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone standard of the European Commission maintained by the Joint Research Centre (JRC) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range from

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-02-25
Joële Viallon, Faraz Idrees, Philippe Moussay, Robert Wielgosz, James E Norris and Joseph T Hodges

As part of the ongoing key comparison BIPM.QM-K1, a comparison has been performed between the ozone national standard of the National Institute of Standards and Technology (NIST) and the common reference standard of the key comparison, maintained by the Bureau International des Poids et Mesures (BIPM). The instruments have been compared over a nominal ozone amount-of-substance fraction range of 0 nmol/mol

更新日期：2020-03-04
• Metrologia (IF 3.447) Pub Date : 2020-01-01
Martina Marzano,Mattias Kruskopf,Alireza R Panna,Albert F Rigosi,Dinesh K Patel,Hanbyul Jin,Stefan Cular,Luca Callegaro,Randolph E Elmquist,Massimo Ortolano

The unique properties of the quantum Hall effect allow one to revisit traditional measurement circuits with a new flavour. In this paper we present the first realization of a quantum Hall Kelvin bridge for the calibration of standard resistors directly against the quantum Hall resistance. The bridge design is particularly simple and requires a minimal number of instruments. The implementation here

更新日期：2020-01-01
• Metrologia (IF 3.447) Pub Date : 2019-01-01
Patrick M C Rourke,Christof Gaiser,Bo Gao,Daniele Madonna Ripa,Michael R Moldover,Laurent Pitre,Robin J Underwood

The principles and techniques of primary refractive-index gas thermometry (RIGT) are reviewed. Absolute primary RIGT using microwave measurements of helium-filled quasispherical resonators has been implemented at the temperatures of the triple points of neon, oxygen, argon and water, with relative standard uncertainties ranging from 9.1 × 10-6 to 3.5 × 10-5. Researchers are now also using argon-filled

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-06-19
Edward Hanson,Douglas Olson,Haijun Liu,Zeeshan Ahmed,Kevin O Douglass

We describe our progress in developing the infrastructure for traceable transient measurements of pressure. Towards that end, we have built and characterized a dual diaphragm shock tube that allows us to achieve shock amplitude reproducibility of approximately 2.3 % for shocks with Mach speeds ranging from 1.26 to 1.5. In this proof-of-concept study we use our shock tube to characterize the dynamic

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-06-12
Nicholas Vlajic,Ako Chijioke

In general, the dynamic sensitivity of a force transducer depends upon the mechanical system in which it is used. This dependence serves as motivation to develop a dynamic force transfer standard, which can be used to calibrate an application transducer in situ. In this work, we SI-traceably calibrate a hand-held force transducer, namely an impact hammer, by using a mass suspended from a thin line

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-01-16
X J Feng,J T Zhang,M R Moldover,I Yang,M D Plimmer,H Lin

This article describes the accurate determination of the molar mass M of a sample of argon gas used for the determination of the Boltzmann constant. The method of one of the authors (Moldover et al 1988 J. Res. Natl. Bur. Stand.93 85-144) uses the ratio of the square speed of sound in the gas under analysis and in a reference sample of known molar mass. A sample of argon that was isotopically-enriched

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-01-16
X J Feng,J T Zhang,H Lin,K A Gillis,J B Mehl,M R Moldover,K Zhang,Y N Duan

We report a new determination of the Boltzmann constant kB using a cylindrical acoustic gas thermometer. We determined the length of the copper cavity from measurements of its microwave resonance frequencies. This contrasts with our previous work (Zhang et al 2011 Int. J. Thermophys.32 1297, Lin et al 2013 Metrologia50 417, Feng et al 2015 Metrologia52 S343) that determined the length of a different

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-01-01
J Fischer,B Fellmuth,C Gaiser,T Zandt,L Pitre,F Sparasci,M D Plimmer,M de Podesta,R Underwood,G Sutton,G Machin,R M Gavioso,D Madonna Ripa,P P M Steur,J Qu,X J Feng,J Zhang,M R Moldover,S P Benz,D R White,L Gianfrani,A Castrillo,L Moretti,B Darquié,E Moufarej,C Daussy,S Briaudeau,O Kozlova,L Risegari,J J Segovia,M C Martín,D Del Campo

The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, followed the recommendation of the Consultative Committee for Units (CCU) on the redefinition of the kilogram, ampere, kelvin and mole. For the redefinition of the kelvin, the Boltzmann constant will be fixed with the numerical value 1.380 649 × 10-23 J K-1. The relative standard uncertainty to be transferred

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-01-01
Christina Liaskos,George Rhoderick,Joseph Hodges,Antonio Possolo,Cassie Goodman,Yong Doo Kim,Dal Ho Kim,Sangil Lee,Nicholas Allen,Marivon Corbel,David Worton,Richard Brown,Paul Brewer

The growing awareness of climate change, and continuing concerns regarding tropospheric and stratospheric chemistry, will require future measurements and standards for compounds linked to these issues. To globally monitor and control the emissions of these species in the atmosphere, it is necessary to demonstrate measurement equivalence at the highest levels of accuracy for assigned values of standards

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-01-01
Mattias Kruskopf,Randolph E Elmquist

Graphene-based quantised Hall resistance standards promise high precision for the unit ohm under less exclusive measurement conditions, enabling the use of compact measurement systems. To meet the requirements of metrological applications, national metrology institutes developed large-area monolayer graphene growth methods for uniform material properties and optimized device fabrication techniques

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-01-01
Stephen Eckel,Daniel S Barker,James A Fedchak,Nikolai N Klimov,Eric Norrgard,Julia Scherschligt,Constantinos Makrides,Eite Tiesinga

Cold atoms are excellent metrological tools; they currently realize SI time and, soon, SI pressure in the ultra-high (UHV) and extreme high vacuum (XHV) regimes. The development of primary, vacuum metrology based on cold atoms currently falls under the purview of national metrology institutes. Under the emerging paradigm of the "quantum-SI", these technologies become deployable (relatively easy-to-use

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2018-01-01
A T Yue,E S Anderson,M S Dewey,D M Gilliam,G L Greene,A B Laptev,J S Nico,W M Snow

A technique for establishing the total neutron rate of a highly-collimated monochromatic cold neutron beam was demonstrated using an alpha-gamma counter. The method involves only the counting of measured rates and is independent of neutron cross sections, decay chain branching ratios, and neutron beam energy. For the measurement, a target of 10B-enriched boron carbide totally absorbed the neutrons

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-12-23
Julia Scherschligt,James A Fedchak,Daniel S Barker,Stephen Eckel,Nikolai Klimov,Constantinos Makrides,Eite Tiesinga

The National Institute of Standards and Technology has recently begun a program to develop a primary pressure standard that is based on ultra-cold atoms, covering a pressure range of 1 × 10-6 Pa to 1 × 10-10 Pa and possibly lower. These pressures correspond to the entire ultra-high vacuum (UHV) range and extend into the extreme-high vacuum (XHV). This cold-atom vacuum standard (CAVS) is both a primary

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-10-24
Kevin J Coakley,Jifeng Qu

In the electronic measurement of the Boltzmann constant based on Johnson noise thermometry, the ratio of the power spectral densities of thermal noise across a resistor at the triple point of water, and pseudo-random noise synthetically generated by a quantum-accurate voltage-noise source is constant to within 1 part in a billion for frequencies up to 1 GHz. Given knowledge of this ratio, and the values

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-10-24
N E Flowers-Jacobs,A Pollarolo,K J Coakley,A E Fox,H Rogalla,W L Tew,S P Benz

A value for the Boltzmann constant was measured electronically using an improved version of the Johnson Noise Thermometry (JNT) system at the National Institute of Standards and Technology (NIST), USA. This system is different from prior ones, including those from the 2011 determination at NIST and both 2015 and 2017 determinations at the National Institute of Metrology (NIM), China. As in all three

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-10-04
Jifeng Qu,Samuel P Benz,Kevin Coakley,Horst Rogalla,Weston L Tew,Rod White,Kunli Zhou,Zhenyu Zhou

Recent measurements using acoustic gas thermometry have determined the value of the Boltzmann constant, k, with a relative uncertainty less than 1 × 10-6. These results have been supported by a measurement with a relative uncertainty of 1.9 × 10-6 made with dielectric-constant gas thermometry. Together, the measurements meet the requirements of the International Committee for Weights and Measures and

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-07-26
Blaza Toman,Michael A Nelson,Mary Bedner

Chemical measurement methods are designed to promote accurate knowledge of a measurand or system. As such, these methods often allow elicitation of latent sources of variability and correlation in experimental data. They typically implement measurement equations that support quantification of effects associated with calibration standards and other known or observed parametric variables. Additionally

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-07-25
Christian Wuethrich,Kenta Arai,Mercede Bergoglio,James A Fedchak,Karl Jousten,Seung Soo Hong,Jorge Torres Guzman

The comparison CCM.P-K15 is a key comparison in pressure involving six laboratories in three regional metrological organizations (RMO). The measurand of the comparison is the accommodation coefficient of two spinning rotating gauge characterized in nitrogen from 0.1 mPa up to 1.0 Pa. The two transfer standards were circulated from November 2009 until March 2011. The circulation consisted of three loops

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-02-28
Leonard Hanssen,B Wilthan,Christian Monte,Jörg Hollandt,Jacques Hameury,Jean-Remy Filtz,Ferruccio Girard,Mauro Battuello,Juntaro Ishii

The National Measurement Institutes (NMIs) of the United States, Germany, France, Italy and Japan, have joined in an inter-laboratory comparison of their infrared spectral emittance scales. This action is part of a series of supplementary inter-laboratory comparisons (including thermal conductivity and thermal diffusivity) sponsored by the Consultative Committee on Thermometry (CCT) Task Group on Thermophysical

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-02-22
Jacob Ricker,Jay Hendricks,Thomas Bock,Pražák Dominik,Tokihiko Kobata,Jorge Torres,Irina Sadkovskaya

The report summarizes the Consultative Committee for Mass (CCM) key comparison CCM.P-K4.2012 for absolute pressure spanning the range of 1 Pa to 10 000 Pa. The comparison was carried out at six National Metrology Institutes (NMIs), including National Institute of Standards and Technology (NIST), Physikalisch-Technische Bundesanstalt (PTB), Czech Metrology Institute (CMI), National Metrology Institute

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-01-17
John Wright,Blaza Toman,Bodo Mickan,Gerd Wübbeler,Olha Bodnar,Clemens Elster

Inter-laboratory comparisons use the best available transfer standards to check the participants' uncertainty analyses, identify underestimated uncertainty claims or unknown measurement biases, and improve the global measurement system. For some measurands, instability of the transfer standard can lead to an inconclusive comparison result. If the transfer standard uncertainty is large relative to a

更新日期：2019-11-01
• Metrologia (IF 3.447) Pub Date : 2017-01-10
C W Meyer,A Solano

A Regional Metrology Organization (RMO) Key Comparison of dew/frost point temperatures over the range -30 °C TO +20 °C was carried out by the National Institute of Standards and Technology (NIST, USA) and the Laboratorio Costarricense de Metrología (LACOMET, Costa Rica), between February 2015 and August 2015. The results of this comparison are reported here, along with descriptions of the humidity

更新日期：2019-11-01
Contents have been reproduced by permission of the publishers.

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