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Aikawa K.,University of Tokyo | Akamatsu D.,University of Tokyo | Akamatsu D.,National Metrology Institute of Japan | Hayashi M.,University of Tokyo | And 9 more authors.
Physical Review Letters | Year: 2010

We report on the direct conversion of laser-cooled K41 and Rb87 atoms into ultracold K41Rb87 molecules in the rovibrational ground state via photoassociation followed by stimulated Raman adiabatic passage. High-resolution spectroscopy based on the coherent transfer revealed the hyperfine structure of weakly bound molecules in an unexplored region. Our results show that a rovibrationally pure sample of ultracold ground-state molecules is achieved via the all-optical association of laser-cooled atoms, opening possibilities to coherently manipulate a wide variety of molecules. © 2010 The American Physical Society.

News Article | November 29, 2016
Site: phys.org

NIST’s Patrick Abbott with one of the two smaller balances, used for the vacuum-to-air studies. Credit: National Institute of Standards and Technology When the kilogram, the world's basic unit of mass, gets a new definition in 2018, it will be based not on a physical artifact but a constant of nature. However, researchers will still need to "realize" the new definition, or translate it into a physical object, to make it possible to distribute the new standard to the laboratories and industries that need it. Of the two methods that are major contenders for this realization process – watt balances and silicon spheres – both require delicate measurements in vacuum. But most day-to-day mass measurements take place in regular air. This means that in order to disseminate the new kilogram, researchers must find reliable ways to compare a mass measured in vacuum to one measured in air. The world's national metrology institutes (NMIs) are each developing protocols to use in their own countries. But someone needs to check to make sure that their various methods are working well and getting comparable results. So the International Bureau of Weights and Measures (BIPM), an intergovernmental organization that has custody over the current official kilogram standard, asked a few NMIs to perform a dry run of their proposed methods of dissemination, as part of a pilot study to ensure that the plans for distributing the new definition are feasible. NIST just completed its dry run this month. "For this pilot study, each NMI has done a primary realization of a kilogram using either a watt balance or silicon sphere," says Patrick Abbott of the Mass and Force Group in NIST's Physical Measurement Laboratory. "The idea was: How well can we take that primary realization and pass it on?" Presently, the U.S. standard for mass is a plum-sized cylinder of platinum-iridium called K20, which is regularly calibrated against the world's current definition for the kilogram – the International Prototype Kilogram (IPK), housed at BIPM headquarters in Paris. After redefinition, K20 will be replaced by a new U.S. standard: the NIST-4 watt balance. NIST staff began the pilot study by calibrating a sample mass, made of platinum-iridium, in their watt balance. But the next step – transferring the calibration to masses in air – was a bit tricky. Air contains water and other impurities that are adsorbed by the surfaces of the masses used in the calibration process. So a mass measured in air will be slightly heavier than that same mass measured in vacuum. The nagging question for metrologists is, by how much? NIST researchers have prepared a couple of ways to overcome this problem. The first involves a room-sized double-decker instrument that uses magnetic levitation to float a mass in the air, to balance it against a mass in vacuum, and do a direct comparison of the two. Eventually, this instrument – called the Magnetic Suspension Mass Comparator – will be the preferred method of disseminating the kilogram. But it is still being constructed and tested, so it was not used in the dry run. The second method involves using a set of smaller instruments at NIST. These balances are able to compare the masses of two objects at a time in either regular air or in vacuum. Prior to the dry run, NIST staff used one of these apparatus to conduct a study gauging exactly how much mass is added to an object when it goes from vacuum to air, based on its material and the smoothness of its surface. With this information, the NIST researchers took the mass that had been calibrated using the watt balance, removed it from vacuum, and compared it – in air – to a pair of stainless steel working standards, of the type that might be used to calibrate customers' weights. The team applied the corrections that it gathered from its adsorption studies to make the jump from vacuum to air. To connect these findings to the current definition for mass, the team also measured all of these test masses against one of the official U.S. mass standards, whose definition is tied to the IPK. Abbott says he expects the BIPM will be ready to share results from the pilot study by early next year. Other participating NMIs include the National Research Council of Canada (NRC Canada) and France's Laboratoire National de Métrologie et d'Essais (LNE), each of which has its own watt balance, as well as the National Metrology Institute of Germany (PTB) and the National Metrology Institute of Japan (NMIJ), which use silicon spheres. Explore further: Vacuums provide solid ground for new definition of kilogram

Takahashi T.,Tohoku University | Kimura Y.,Tohoku University | Niwa K.,National Metrology Institute of Japan | Ohmiya Y.,Japan National Institute of Advanced Industrial Science and Technology | And 3 more authors.
Journal of Investigative Dermatology | Year: 2013

Adenosine 5′-triphosphate (ATP) release from keratinocytes has been observed in various stress models in vitro, but studies demonstrating epidermal ATP release in vivo are limited. To visualize extracellular ATP (eATP) in vivo, we developed enhanced green-emitting luciferase immobilized on agarose beads (Eluc-agarose). Subcutaneous injection of Eluc-agarose together with ATP into the dorsal skin of BALB/c mice following intraperitoneal luciferin injection produced detectable and measurable bioluminescence using an in vivo imaging system. Using Eluc-agarose, we demonstrated in vivo that bright bioluminescence was observed from 1 to 20 minutes after repeated tape stripping of murine skin. This bioluminescence was suppressed by the local administration of apyrase. Eluc-agarose bioluminescence was observed only in tape-stripped skin with transepidermal water loss (TEWL) between 100 and 140 g m 2 h -1, indicating a loss of bioluminescence with excessive tape stripping (TEWL>140 g m -2 h -1). Histologically, tape-stripped skin with detectable eATP had a viable epidermis and a subepidermal neutrophil infiltrate, and administration of apyrase reduced the inflammatory infiltrate. Neither a viable epidermis nor an upper dermal neutrophil infiltrate was observed after excessive tape stripping. These results suggest that tape stripping prompts ATP release from viable keratinocytes, which facilitates inflammatory cell migration. Eluc-agarose may be useful in the in vivo detection of eATP in murine models of skin diseases. © 2013 The Society for Investigative Dermatology.

Yamada T.,National Metrology Institute of Japan
IEEE Transactions on Instrumentation and Measurement | Year: 2013

High-accuracy frequency, amplitude, and phase estimation methods for asynchronous sampling are presented. The proposed estimation methods are based on phase difference estimation, compensation of number of samples, and a modified discrete Fourier transform. This study focused on processing signals in substation automation systems that comply with IEC 61850. Some simulation tests were conducted in cases of pure and distorted sinusoids, and the frequency, amplitude, and phase errors of the fundamental and harmonics are evaluated at fundamental frequencies around 50 Hz at fixed sampling rates of 4 kHz and 12.8 kHz (i.e., 80 and 256 samples per period). Dependence of each estimation accuracy on a fraction of number of samples is discussed. © 2013 IEEE.

Yoshioka M.,National Metrology Institute of Japan | Kikuchi T.,National Metrology Institute of Japan
Japanese Journal of Applied Physics | Year: 2011

An estimation using a theoretical formula for the amplitude decrease of discretized hydrophone output voltage due to imperfect synchronous averaging using an external trigger in our ultrasonic field parameter calibration is described. The estimation formula is derived from a statistically expected value considering the temporal difference of the trigger as a random variable with a uniform distribution in the range of the sampling period. As a result of comparing the formula and the measured hydrophone output voltage amplitude for ultrasound up to 20 MHz, it is confirmed that the formula can estimate the amplitude decrease and be used for correction to obtain accurate ultrasonic field measurement. © 2011 The Japan Society of Applied Physics.

Yamaguchi Y.,National Metrology Institute of Japan | Yamada Y.,National Metrology Institute of Japan | Ishii J.,National Metrology Institute of Japan
International Journal of Thermophysics | Year: 2015

At the National Metrology Institute of Japan (NMIJ), a new monochromator-based absolute radiometric calibration system for radiation thermometers has been developed with a supercontinuum (SC) source instead of a tungsten-halogen lamp. Compared with halogen lamps, remarkably higher spectral radiance can be obtained from the SC-monochromator-based system because the SC optical radiation can be efficiently coupled into the narrow entrance slit of the monochromator, thus enabling coupling of the monochromatic light from the exit slit into an integrating sphere, which serves as a wavelength-tunable source for calibrating radiation thermometers against a reference detector. In this work, the setup and preliminary measurement results of the SC-source-based system at the NMIJ are described. Techniques for power stabilization, wavelength determination, spatial-uniformity improvement, and interference fringe reduction are applied to the system. The uncertainties of the facility for thermodynamic temperature measurements are estimated. © 2015, Springer Science+Business Media New York.

Yamada Y.,National Metrology Institute of Japan | Ishii J.,National Metrology Institute of Japan
Japanese Journal of Applied Physics | Year: 2011

Two novel techniques of compensating for unknown distributed emissivity in temperature measurement by thermal imagers are presented. For both techniques the reflected image of a planar auxiliary source is superimposed on the thermal image of the object. In the first, the true temperature of the object is obtained by treating it as a blackbody when the radiance distribution, corresponding to emissivity pattern of the object, disappears. In the second, the reflectance ratio at two areas in the thermal image is utilized to compensate for emissivity. In this paper, principle of the emissivity compensation and preliminary test results are presented, and the procedures and their capabilities are demonstrated. The features of the schemes, such as elimination of the size-of-source effect, are discussed. The method is expected to become powerful tools for temperature distribution measurements in various applications, most notably the monitoring of local heat generation in highly-integrated or power electronicdevices. © 2011 The Japan Society of Applied Physics.

Ohata M.,National Metrology Institute of Japan | Miura T.,National Metrology Institute of Japan
Analytica Chimica Acta | Year: 2014

The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH3) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH3 solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive. © 2014 Elsevier B.V.

Watanabe T.,National Metrology Institute of Japan
20th IMEKO World Congress 2012 | Year: 2012

SelfA (Self-calibratable Angle device) rotary encoder has an advanced function that can detect and estimate the angular deviation in the signal by itself. National Metrology Institute of Japan (NMIJ) developed the small and low cost SelfA encoder with keeping high accuracy ±0.2. Copyright © (2012) by the International Measurement Federation (IMEKO).

Shimaoka K.,National Metrology Institute of Japan
CPEM Digest (Conference on Precision Electromagnetic Measurements) | Year: 2010

A simple and rigorous method for measuring the equivalent source reflection coefficient of three-port devices is reported in this paper. It is shown that two-port scattering-parameter measurements of a three-port device, one of the output ports of which was alternately terminated with two different reflecting devices, give an accurate value of the equivalent source reflection coefficient. © 2010 IEEE.

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