Santiago de Querétaro, Mexico
Santiago de Querétaro, Mexico

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Koffman A.,U.S. National Institute of Standards and Technology | Zhang N.F.,U.S. National Institute of Standards and Technology | Wang Y.,U.S. National Institute of Standards and Technology | Shields S.,U.S. National Institute of Standards and Technology | And 12 more authors.
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2012

A key comparison of capacitance has been carried out by the Inter-American Metrology System (SIM) Regional Metrology Organization (RMO). The purpose is to establish the degree of equivalence of capacitance between the national metrology institutes (NMIs) within SIM, in support of the International Committee for Weights and Measures (CIPM) Mutual Recognition Agreement (MRA). The key comparison artifact is a 10 pF commercial fused-silica standard capacitor. Seven SIM NMIs participated in the comparison. Results linking the SIM.EM-K4 to CCEM-K4 will show agreement of SIM NMIs to other RMOs. © 2012 IEEE.


Moreno J.A.,CENAM | Cote M.,NRC | Koffman A.,U.S. National Institute of Standards and Technology | Castro B.I.,ICE | And 6 more authors.
CPEM 2016 - Conference on Precision Electromagnetic Measurements, Conference Digest | Year: 2016

A key comparison of 10 mH inductance standards at 1 kHz has been carried out with the participation of seven National Metrology Institutes (NMI's) of the Inter-American Metrology System (SIM), within the frame of the International Committee for Weights and Measures Mutual Recognition Arrangement (MRA), which was piloted by CENAM, Mexico. Three previously characterized commercial inductors, contained in individual enclosures with controlled temperature were used as traveling standards. This paper presents the results and technical details of the comparison. © 2016 IEEE.


Perez Urquiza M.,CENAM | Acatzi Silva A.I.,CNRDOGM
Metrologia | Year: 2014

Three certified reference materials produced from powdered seeds to measure the copy number ratio sequences of p35S/hmgA in maize containing MON 810 event, p35S/Le1 in soybeans containing GTS 40-3-2 event and DREB1A/acc1 in wheat were produced according to the ISO Guides 34 and 35. In this paper, we report digital polymerase chain reaction (dPCR) protocols, performance parameters and results of copy number ratio content of genetically modified organisms (GMOs) in these materials using two new dPCR systems to detect and quantify molecular deoxyribonucleic acid: the BioMark® (Fluidigm) and the OpenArray® (Life Technologies) systems. These technologies were implemented at the National Institute of Metrology in Mexico (CENAM) and in the Reference Center for GMO Detection from the Ministry of Agriculture (CNRDOGM), respectively. The main advantage of this technique against the more-used quantitative polymerase chain reaction (qPCR) is that it generates an absolute number of target molecules in the sample, without reference to standards or an endogenous control, which is very useful when not much information is available for new developments or there are no standard reference materials in the market as in the wheat case presented, or when it was not possible to test the purity of seeds as in the maize case presented here. Both systems reported enhanced productivity, increased reliability and reduced instrument footprint. In this paper, the performance parameters and uncertainty of measurement obtained with both systems are presented and compared. © 2014 BIPM & IOP Publishing Ltd.


Kyriazis G.A.,National Institute of Metrology of Brazil | Moreno J.A.,CENAM | Melcher J.,PTB
18th IMEKO TC4 Symposium on Measurement of Electrical Quantities 2011, Part of Metrologia 2011 | Year: 2011

The traceability chain to derive the capacitance unit from the quantum Hall resistance comprises some coaxial bridges. These bridges employ a main two-stage inductive voltage divider to provide the voltage ratio needed. One such divider has recently been constructed and calibrated at Inmetro. The design techniques responsible for the small ratio errors of the device are detailed. Copyright © 2011 by the International Measurement Confederation (IMEKO) All rights reserved.


Shtin N.,Centro Ind Los Pinos | Romero J.M.L.,CENAM
Asia-Pacific Microwave Conference Proceedings, APMC | Year: 2010

In this paper we present the design and preliminary results of an experimental evaluation of C-band microwave oscillators with combined frequency stabilization based on Sapphire Whispering Gallery Resonators (WGR). Design features and phase noise performance of both the main oscillator loop and a frequency stabilization system are presented. The frequency stabilization loop has been implemented using a high sensitivity "noiseless" frequency discriminator based on a traveling wave WGR. The intrinsic phase noise of the oscillator electronics has been minimized utilizing low 1/-noise silicon and SiGe discrete components and ICs. The single-sideband phase noise of 128 dBc/Hz and 133 dBc/Hz at 1 kHz offset has been measured for free-running oscillators with Pres = 0.15 W and Pres = 0.4 W respectively. An estimate for the phase noise of the stabilized oscillators has been made involving a phase transfer function approach. © 2010 IEICE Institute of Electronics Informati.


Marmet L.,National Research Council Canada | Dube P.,National Research Council Canada | Shtin N.,SMK Electronica S.A. de C.V. | Lopez R.J.M.,CENAM
2013 Joint European Frequency and Time Forum and International Frequency Control Symposium, EFTF/IFC 2013 | Year: 2013

A preliminary calculation of the frequency shifts resulting from the distributed phase of a rectangular cavity is used to model frequency measurements of the fountain clock NRC-FCs1. The calculation is based on a numerical evaluation of the cavity field made with a finite element EM solver. The frequency shift is obtained by solving the Bloch-equations numerically along the path of the atoms on the free-fall trajectories through the cavity. We study the frequency shifts as a function of the launch direction, the tilt of the physics package and offsets in the position of the MOT relative to the axis defined by the state-selection cavity and the Ramsey cavity. © 2013 IEEE.


Vogl J.,BAM | Kipphardt H.,BAM | Del Rocio Arvizu Torres M.,CENAM | Manzano J.V.L.,CENAM | And 15 more authors.
Metrologia | Year: 2014

The measurement of the purity of zinc based on the determination of six analytes is reported. Each participant was asked to report one result for the sum of the six requested impurities and the individual results for the six impurities. The results had to be reported in mass fractions, accompanied by a full uncertainty statement including a combined standard uncertainty and an expanded uncertainty with a coverage factor applied. Each participant was free to use any suitable method(s) for the measurement of the individual impurities. In case several methods were used for one specific impurity, only one (composite) result had to be reported. For Cd and Ni a spread unusually high for IDMS was observed in parallel measurements. This spread is reflected in the relative uncertainties for Cd and Ni, which are untypically large for double IDMS analysis. For the purpose of impurity analysis in zinc, comparability of measurement results for aluminium as an analyte is possible within the target uncertainty of 30 %.


Ortega-Cortes R.,CENAMEP AIP | Mendez-Lango E.,CENAM | Araolaza-Rodriguez A.,CENAMEP AIP
AIP Conference Proceedings | Year: 2013

We present the results of the design, construction, filling and test of thermometric cell, to reproduce the triple point of mercury in the Temperature Laboratory of Centro Nacional de Metrología de Panamá AIP (CENAMEP AIP). This cell will be included in the group of thermometric cells of the laboratory. With this cell CENAMEP-AIP is covering the-39°C to 660°C range. This new cell offers the opportunity to reproduce the primary temperature defined by ITS-90 of-38.8344° C, and was built with 0.68 kg of mercury ultra-pure certified by the National Institute of Standards and Technology from United States (NIST-EEUU). The reproducibility obtained with thermometric cell of mercury is approximately one thousandth of kelvin (1 mK). This value satisfies according to current laboratory equipment. © 2013 AIP Publishing LLC.


Di Lillo L.,INTI | Yasuda E.,INTI | Lipe T.,U.S. National Institute of Standards and Technology | Campos S.,CENAM | And 8 more authors.
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2014

A key comparison of the AC-DC current transfer difference has been carried out by the Inter-American Metrology System (SIM) Regional Metrology Organization (RMO). Its purpose was to establish an equivalence of AC-DC current transfer difference at 10 mA and 5 A between the national metrology institutes (NMIs), in support of the International Committee for Weights and Measures (CIPM) Mutual Recognition Agreement (MRA). The comparison artifact was a Planar Multijunction Thermal Converter (PMJTC) at 10 mA and a 5 A shunt at 5 A measurements. Six SIM NMIs participated in the comparison as well as NIS, National Institute of Standard of Egypt. Results linking the SIM.EM-K12 to CCEM-K12 show agreement of SIM NMIs to other RMOs. © 2014 IEEE.


Shtin N.A.,CENAM | Romero J.M.L.,CENAM
Microwave and Optical Technology Letters | Year: 2010

This article deals with a design and performance evaluation of a medium power C-band array amplifier based on SiGe hetero-junction bipolar transistors (HBT). The proposed power amplifier (PA) contains four identical HBT stages coupled by the means of compact power splitting/summing microstrip networks. The designed PA exhibits a very low phase noise level of - 165 dBc/Hz at 1 kHz offset frequency, and it is distinguished by a high output power having P 1dB = +26 dBm and high power added efficiency approaching to 40%. © 2009 Wiley Periodicals, Inc.

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