Fellmuth B.,Physikalisch - Technische Bundesanstalt |
Wolber L.,Physikalisch - Technische Bundesanstalt |
Head D.I.,National Physical Laboratory United Kingdom |
Hermier Y.,French National Conservatory of Arts and Crafts |
And 12 more authors.
Metrologia | Year: 2012
An overview of the results of an international star intercomparison of low-temperature fixed points is given. Between 1997 and 2005, 68 sealed triple-point cells (STPCs) of the twelve laboratories represented by the authors were investigated at PTB. The STPCs are used to realize the triple points of hydrogen, neon, oxygen and argon as defining fixed points of the International Temperature Scale of 1990, ITS-90. The melting curves (MCs) of all STPCs have been measured on the same experimental equipment, adhering strictly to a single measurement program. This protocol enables separation of the effects influencing the MCs and direct comparison of the thermal behaviour of the STPCs, which are quite different with respect to design, age, gas source and filling technology. In the paper, special emphasis is given to the spread of the liquidus-point temperatures and to the uncertainty of their determination. Connections between the star intercomparison and completed and ongoing international activities are also discussed. © 2012 BIPM & IOP Publishing Ltd.
Tew W.L.,U.S. National Institute of Standards and Technology |
Rusby R.L.,National Physical Laboratory United Kingdom |
Lin P.,CAS Technical Institute of Physics and Chemistry |
Lipinski L.,Instytut Niskich Temperatur i Badan Strukturalnych |
And 2 more authors.
International Journal of Thermophysics | Year: 2015
The worldwide history and present state of development of rhodium–iron resistance thermometers (RIRTs) is briefly reviewed. A standardized interpolation method using RIRTs with the nominal composition of 0.5 % Fe (by mole) is presented, with examples using data taken from 60 RIRTs made from a variety of wire batches and sources worldwide over the last 40 years. The parameterization exploits the favorable characteristics of the Cragoe reduced resistance Z(τ) and a suitably reduced temperature τ. A reference function Zref(τ) which approximates the average characteristics of selected wire is derived for use over the interval 0.65 K to 24.5561 K on the ITS-90. The deviations of real RIRT data from this reference function are examined, and simple four-parameter Fourier-series solutions for the resulting deviation curves are presented. Despite the fact that the wire samples may be of different origins or state-of-anneal, it was found that the interpolations are successful for most of the samples studied over the 4.2 K to 24.5561 K interval, at the level of ≈1 mK standard uncertainty or less. This method would allow for calibrations of most RIRTs over this interval using only six calibration points, permitting an efficiency not achievable using the common least-squares curve-fitting calibration methods. The potential of this formalism for a standardized interpolation scheme using RIRTs is discussed. © 2015, Springer Science+Business Media New York (Outside the USA).
Instytut Niskich Temperatur I Badan Strukturalnych | Date: 2014-01-27
A process for the manufacture of magnetic ceramic is provided including the steps of: die compacting a powder composition into a compacted body, the composition including a mixture of soft magnetic, iron or iron-based powder, core particles of which are surrounded by an electrically insulating, inorganic coating an amount of 1 to 35% by weight of the composition; and heating and pressing the compacted body in an atmosphere to a temperature and a pressure below the decomposition temperature and pressure of the magnetic, iron or iron-based powder.
Deren P.J.,Instytut Niskich Temperatur i Badan Strukturalnych |
Lemanski K.,Instytut Niskich Temperatur i Badan Strukturalnych
Journal of Luminescence | Year: 2014
LaAlO3: Ho3+(0.5-10%) and CaTiO3: Ho3+ (0.1-2%) nanosized perovskites were prepared with the Pechini and sol-gel method, respectively. The spectroscopic properties of CaTiO3: Ho 3+ were investigated for the first time. The cross relaxation energy transfer processes were determined as a function of Ho3+ concentration, by examination of the two strongest transitions observed in the visible region arising from 5S2 and 5F5 multiplets. The cross relaxation processes for the investigated Ho3+ levels were described. It was found that the clustering processes for CaTiO3 is so strong, that increase of dopant concentration weakly influence the cross relaxation processes, while in LaAlO3, where dopants are located randomly in the crystal lattice, clear monotonic dependence is observed. © 2014 Elsevier B.V.
Sharma S.K.,Chimie Paristech |
Bessiere A.,Chimie Paristech |
Gourier D.,Chimie Paristech |
Sraiki G.,Chimie Paristech |
And 12 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014
Red emitting long-lasting phosphorescence (LLP) material, are useful biomarker for small animal in vivo imaging. We report here our investigations on the optical features of chromium doped AB2O4 spinels (A=Zn, Mg and B=Ga, Al⋯) suitable for such applications. It is possible to tune the emission wavelengths of Cr3+ by a crystal field variation to be well centered in the biological window and it is also possible to adjust the traps depth in order to better control the release of the traps. These traps are therefore stable at room temperature and could be emptied by thermal or near infrared source making this material a potential new photostimulated/ optically compound. Photoluminescence (PL) and thermally stimulated luminescence (TSL) studies are reported. © 2014 SPIE.