| 1. |
- Nysten,, Per
(författare)
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Age of the rhyolite hosting the Ultevis Mn-Fe-Ba-As mineralisation, northern Sweden
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A feldspar-porphyric Svecofennian rhyolite associated with Mn-mineralisations at Ultevis, west of Jokkmokk, northern Sweden, has been dated to 1872 ± 9 Ma. This figure also gives a maximum age of deposition of the stratigraphically overlaying sedimentary rock sequence (the Snavva–Sjöfall group). The position of Mn-Fe-Ba-As-F-U-(W-Mo) mineralisations is discussed in relation to the transition from volcanic to sedimentary environments in the Tjåmotis–Ultevis area.
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| 2. |
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| 3. |
- Amcoff, Örjan, et al.
(författare)
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Bonanzamalm i mikroskala
- 1998
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Ingår i: Geologiskt forum. - 1104-4721. ; :18, s. 9-11
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 4. |
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| 5. |
- Bonazzi, Paola, et al.
(författare)
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Multi-analytical approach to solve the puzzle of an allanite-subgroup mineral from Kesebol, Vastra Gotaland, Sweden
- 2009
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Ingår i: American Mineralogist. - : Mineralogical Society of America. - 0003-004X .- 1945-3027. ; 94:1, s. 121-134
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Tidskriftsartikel (refereegranskat)abstract
- Dark-brownish. euhedral crystals of an "allanite-like" mineral occur in a hematite-impregnated Mn-silicate rock at Kesebol, Vastra Gotaland, Sweden, associated with gasparite-(Ce), chernovite-(Y), rhodonite, andradite, manganoan calcite, and quartz. A structural study was carried out on single crystals-untreated, heated in air, and heated under inert atmosphere-combined with Mossbauer spectroscopy and TEM investigation. In all the untreated crystals the mean < M3-O > distance indicates that Me2+(Me = Mn, Fe) prevails at this site (< M3-O > in the range 2.169-2.180 angstrom), in contrast with chemical data obtained by EPMA that yield a simplified formula Ca(REE2/33+square(1/3))Me-3(3+)(SiO4)(Si2O7) O(OH), when normalized to Si = 3.00 apfu. Moreover, when a crystal is heated in air, all geometrical and structural variations indicate the development of an oxidation-dehydrogenation reaction, thus confirming that M3 is occupied by divalent cations before heating. The corresponding dehydrogenation is confirmed by a dramatic lengthening of the donor-acceptor distance. A crystal was annealed under inert atmosphere to verify possible effects of radiation damage on the polyhedral volumes. After prolonged annealing at 700 C, a slight decrease of the unit-cell parameters is observed, suggesting restoring of crystallinity from a "partially metamict" state. Nonetheless, even in the annealed crystal, the < M3-O > distance is still consistent with a dominance of divalent cations at the M3 site. For all the examined crystals, structural data point to an octahedral cation population as follows: M1 = (Me3+, Al); M2 = (Al, Me3+). M3 = (Me2+, Me3+). This assumption is also in agreement with the Mossbauer spectrum, which was fitted to two Lorentzian quadrupole doublets for Fe3+ and one for Fe2+. Values of the isomer shifts (0.36 and 0.37 mm/s for Fe3+; 1.11 mm/s for Fe2+) and the quadrupole splitting (1.96 and 1.02 for Fe3+; 1.90 for Fe2+) show that Fe2+ (similar to 12% of the total iron) is located in M3, while Fe3+ occupies M I and, to lesser extent, M2. TEM-EDS investigations have revealed chemical heterogeneities related to different degree of radiation damage. In particular, areas showing poor crystallinity are relatively enriched in Si and O with respect to the highly crystalline areas, thus suggesting that EPMA chemical data are biased by the presence of metamict areas enriched in SiO2 and likely in H2O. EPMA data were therefore corrected for the excess of silica. The cation population after correction is in keeping with the structural and spectroscopic data. Disregarding minor substitutions, the ideal chemical formula for the epidote-group mineral from Kesebol is CaREEFe3+AlMn2+(Si2O7)(SiO4)O(OH), which is related to ferriallanite-(Ce) by the substitutional vector (M3)(Mn2+) -> M3 (Fe2+).
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| 6. |
- Delsing, Per, 1959, et al.
(författare)
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The 2019 surface acoustic waves roadmap
- 2019
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Ingår i: Journal of Physics D: Applied Physics. - : IOP Publishing. - 1361-6463 .- 0022-3727. ; 52:35
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Forskningsöversikt (refereegranskat)abstract
- Today, surface acoustic waves (SAWs) and bulk acoustic waves are already two of the very few phononic technologies of industrial relevance and can been found in a myriad of devices employing these nanoscale earthquakes on a chip. Acoustic radio frequency filters, for instance, are integral parts of wireless devices. SAWs in particular find applications in life sciences and microfluidics for sensing and mixing of tiny amounts of liquids. In addition to this continuously growing number of applications, SAWs are ideally suited to probe and control elementary excitations in condensed matter at the limit of single quantum excitations. Even collective excitations, classical or quantum are nowadays coherently interfaced by SAWs. This wide, highly diverse, interdisciplinary and continuously expanding spectrum literally unites advanced sensing and manipulation applications. Remarkably, SAW technology is inherently multiscale and spans from single atomic or nanoscopic units up even to the millimeter scale. The aim of this Roadmap is to present a snapshot of the present state of surface acoustic wave science and technology in 2019 and provide an opinion on the challenges and opportunities that the future holds from a group of renown experts, covering the interdisciplinary key areas, ranging from fundamental quantum effects to practical applications of acoustic devices in life science.
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| 7. |
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| 8. |
- Holmqvist, Bertil, et al.
(författare)
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Bergkristall
- 2004
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Ingår i: Geologiskt forum. - 1104-4721. ; 11:41, s. 18-25
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Holmqvist, Bertil, et al.
(författare)
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Smaragditgabbro i Alperna
- 2002
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Ingår i: Geologiskt Forum. ; 34, s. 18-25
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Tidskriftsartikel (refereegranskat)
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| 10. |
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