Characterization of non-aged and aged modern Prussian Blue pigments by Mössbauer spectroscopy, x-ray powder diffraction and x-ray absorption spectroscopy

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Micro-crystalline inclusions analysis by PIXE and RBS

A characteristic feature of the nuclear microprobe using a 3 MeV proton beam is the long range of particles (around 70 \mu m in light matrices). The PIXE method, with EDS analysis and using the multilayer approach for treating the X-ray spectrum allows the chemistry of an intra-crystalline inclusion to be measured, provided the inclusion roof and thickness at the impact point of the beam (Z and e, respectively) are known (the depth of the inclusion floor is Z + e). The parameter Z of an inclusion in a mineral can be measured with a precision of around 1 \mu m using a motorized microscope. However, this value may significantly depart from Z if the analyzed inclusion has a complex shape. The parameter e can hardly be measured optically. By using combined RBS and PIXE measurements, it is possible to obtain the geometrical information needed for quantitative elemental analysis. This paper will present measurements on synthetic samples to investigate the advantages of the technique, and also on natural solid and fluid inclusions in quartz. The influence of the geometrical parameters will be discussed with regard to the concentration determination by PIXE. In particular, accuracy of monazite micro-inclusion dating by coupled PIXE-RBS will be presented

Electrodeposition of metals and magnetic alloys onto conducting polymeric substrates

peer reviewedA new composite material prepared by mixing polycarbonate with carbon black has been tested as new kind of cathode, This material has been compared with a conducting polymer precipitated onto polycarbonate, both in aqueous and organic solutions. We report some examples of electrodeposition of magnetic alloys (Lanthanides/Transition metals) in Formamide, In this medium, the use of thin polypyrrole films cathodes had remained impossible, The preparation of amorphous and magnetic alloys onto PC/carbon black is evidenced by RES

Early Medieval Tesserae in Northwestern Europe

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A gemmological study of the reliquary crown of Namur, Belgium

The reliquary crown, hosted in the diocesan museum of Namur, was produced during the beginning of the 13th century to shelter a fragment of the holy crown of thorns. This beautiful piece of goldsmithery is made of eight gold plates, topped by round lobes, and connected to each other by hinges blocked with a pin decorated by a pearl. The crown is decorated by filigrees, flowers, and approximately 400 pearls and coloured (green, reddish pink, turquoise, red, blue) stones showing simple cutting with various sizes and shapes. Raman and portable X-ray fluorescence spectrometer (pXRF) techniques have been used to determine the nature and sources of all samples, as well as the composition of filigrees. Analyses have identified emeralds from Pakistan, reddish pink spinels from Tajikistan, red almandine garnets from India, turquoise from Iran, blue sapphires from Sri Lanka or Myanmar, and European pearls. The filigrees contain approximately 86 wt % Au, 7 wt % Ag, and 7 wt % Cu, thus confirming a gold-rich composition. The gemstones, contemporary with the crown, probably arrived in Europe by the silk trade road.</p

Electrodeposition of metals and magnetic alloys onto conducting polymeric substrates

A new composite material prepared by mixing polycarbonate with carbon black has been tested as new kind of cathode. This material has been compared with a conducting polymer precipitated onto polycarbonate, both in aqueous and organic solutions. We report some examples of electrodeposition of magnetic alloys (Lanthanides/Transition metals) in Formamide. In this medium, the use of thin polypyrrole films cathodes had remained impossible. The preparation of amorphous and magnetic alloys onto PC/carbon black is evidenced by RBS

Characteristics of the iron moment in Dy-Fe and Dy-FeCo amorphous alloys studied by X-ray magnetic circular dichroism

The local magnetic moment of Fe in Dy-Fe and Dy-FeCo amorphous alloys has been studied using X-ray absorption spectroscopy and X-ray magnetic circular dichroism (XMCD). The Fe orbital and spin magnetic moments have been obtained for a range of alloy compositions by applying the sum rules to the XMCD spectra. The room temperature variations of the average components of the Fe moments as a function of Dy concentration and with the substitution of Fe by Co have been determined. A sharp reversal of the total magnetic moment was found at 28 +/- 1 at% Dy for both alloys. (C) 2000 Elsevier Science B.V. All rights reserved