| 1. |
- Qvarford, M., et al.
(författare)
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Polarisation-dependent X-ray absorption in high- and low-Tc Bi2Sr2Can-1CunO4+2n superconductors
- 1993
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Ingår i: Physica C: Superconductivity and its Applications. - : Elsevier BV. - 0921-4534. ; 214:1-2, s. 119-126
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Tidskriftsartikel (refereegranskat)abstract
- Taking advantage of the linear polarisation of synchrotron radiation, the polarisation dependence of the O K and Cu L3 X-ray absorption edges has been compared for in situ cleaved Bi2Sr2CaCu2O8 and Bi2Sr2CuO6 single crystals. The X-ray absorption spectra were measured by means of total electron yield detection. The spectra show for both crystals that the lowest unoccupied Cu 3d and O 2p orbitals are dominantly oriented parallel to the a-b plane, but also the presence of a small amount of unoccupied orbitals oriented perpendicular to the a-b plane can be deduced from both the O K and Cu L3 absorption spectra. A shift of the order of 0.5 eV between absorption into the in-plane and the out-of-plane Cu 3d orbitals was measured for the Bi2Sr2CaCu2O8 crystal, but no such shift was found for the Bi2Sr2CuO6 crystal.
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| 2. |
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| 3. |
- Berg, C., et al.
(författare)
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Observation of a low-binding-energy peak in the 2p core-level photoemission from oxidized Al(111)
- 1993
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Ingår i: Physical Review B (Condensed Matter). - 0163-1829. ; 47:19, s. 13063-13066
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Tidskriftsartikel (refereegranskat)abstract
- High-resolution photoemission studies of oxidation of the Al(111) surface have been performed. The appearance of a component at lower binding energy than the metallic bulk Al emission in the Al 2p spectrum at oxygen exposures above ∼50 langmuir (1 L = 10-6 Torr s) is argued to be due to Al atoms which do not bond directly to oxygen atoms at the oxide-metal interface. Low-energy electron diffraction initially shows a 1×1 structure, which subsequently fades away at higher oxygen exposures, 400 L.
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| 4. |
- Bergendal, T, et al.
(författare)
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A radiological inventory of possible sites for cylinder implants in edentulous regions of the jaws : An epidemiological study
- 1994
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Ingår i: Swedish Dental Journal. - 0347-9994. ; 18:3, s. 75-85
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Tidskriftsartikel (refereegranskat)abstract
- Implant treatment is nowadays requested as an alternative mode of treatment for both total and partial edentulousness. The purpose of the study was to assess the maximum number of possible implant sites in a group of adults. The study material comprised 579 persons divided into the age-groups 20, 30, 40, 50, 60 and 70 years. Based on radiological examination, the subjects were grouped according to Eichner's index. They comprised both dentate and edentulous individuals. Templates, marked with cylinder implants of different dimensions, were placed over edentulous regions. The possible number of cylinder-shaped endosseous implants that could be placed anterior to the second molar was assessed in relation to bone availability and anatomical structures. Gaps treated with fixed bridges were not registered. Altogether 1,048 presumptive fixture sites were marked, of which 78% in the age-groups 60 and 70 years. Eichner groups C 1-3, which comprised the edentulous persons, constituted 12% of the subjects and accounted for 57% of the possible number of implants. All edentulous mandibles and 70% of the edentulous maxillae were judged suitable for placement of implants. On average 5.5 and 5.8 sites were marked per edentulous maxilla and mandible, respectively. Groups B1-4 comprised 21% of the subjects and accounted for 37% of the implants. It is discussed that implant treatment in totally edentulous jaws will increase in relative terms in Sweden as in other Scandinavian countries, i.e. the percentage of edentulous jaws treated with implants will increase. In absolute terms, however, the treatment will probably decrease owing to a marked decrease in the number of edentulous individuals. The future need for implant treatment in the residual dentition will probably increase but it is difficult to predict by how much.
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| 5. |
- HOLBACK, B, et al.
(författare)
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THE FREJA WAVE AND PLASMA-DENSITY EXPERIMENT
- 1994
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Ingår i: SPACE SCIENCE REVIEWS. - : KLUWER ACADEMIC PUBL. ; 70:3-4, s. 577-592
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Recension (övrigt vetenskapligt/konstnärligt)abstract
- The Wave Experiment, F4, on the Swedish/German satellite Freja, is designed to measure the electric wave fields up to 4 MHz, the magnetic wave fields up to 16 kHz and the plasma density and its relative variations up to 2 kHz. Six wave signals and four de
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| 6. |
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| 7. |
- Lundgren, Dan, et al.
(författare)
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The use of a new bioresorbable barrier for guided bone regeneration in connection with implant installation. Case reports.
- 1994
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Ingår i: Clinical oral implants research. - 0905-7161. ; 5:3, s. 177-84
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Tidskriftsartikel (refereegranskat)abstract
- This report presents 4 cases with 6 implant exposures after the installation of Brånemark System implants which called for treatment applying the guided bone regeneration technique. A bioresorbable barrier (GUIDOR Matrix Barrier) was used to cover the defects, 4 defects with and 2 without the support of autologous bone chips. Complete bone filling was found in 4 (2 without and 2 with bone chips) and partial filling in 2 (with bone chips) of the treated defects, as registered at the abutment connection 6-7 months after surgery. Besides its ability to serve as a barrier for guided bone regeneration, it was found that the matrix barrier had the following properties; biocompatibility observed as uneventful tissue healing, malleability facilitating the clinical handling and ability to be resorbed within 6 to 7 months, as evaluated by clinical inspection. The observations of the present case reports indicate that the tested barrier may be used for guided bone regeneration in connection with implant installation. It is advisable, however, to use a supporting material to prevent barrier collapse, although bone regeneration can be achieved in certain situations without such material if the defect morphology is favourable.
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| 8. |
- QVARFORD, M, et al.
(författare)
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X-RAY-ABSORPTION AND RESONANT-PHOTOEMISSION STUDY OF CA IN THE HIGH-TEMPERATURE SUPERCONDUCTOR BI2SR2CACU2O8
- 1992
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Ingår i: Physical Review B Condensed Matter. - 0163-1829 .- 1095-3795. ; 46:21, s. 14126-14133
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Tidskriftsartikel (refereegranskat)abstract
- The electronic structure of Ca in the high-temperature superconductor Bi2Sr2CaCu2O8 has been studied by x-ray-absorption spectroscopy and resonant-photoemission at the Ca L2,3 absorption edge. In the x-ray-absorption spectrum no edge structure is seen at the energy corresponding to the Ca 2p3/2 core-level binding energy, in agreement with the very low Ca density of states at the Fermi level predicted by band-structure calculations. Furthermore, the crystal-field splitting of the Ca 3d level, which is characteristic of ionic Ca compounds, is clearly observed in the x-ray-absorption spectrum. The photoemission spectra display strong resonant enhancements of the Ca 3s and 3p core levels as well as strong changes in the intensity and the line shape of the Ca L2,3M2,3M2,3 Auger structure at the Ca L2,3 threshold, showing the localized nature of the 3d states in core ionized Ca. The 3d induced spectator shift of the Ca L2,3M2,3M2,3 complex is fairly small as compared to what has been reported for CaF2, indicating that the screening of the normal Auger final state by the charge carriers in the surrounding Cu-O2 layers is quite efficient. From the Ca L2,3M2,3M2,3 data it is also suggested that, at the Ca L2 threshold, the excited 3d electron participates in a Coster-Kronig-type decay resulting in a 2p3/2 core hole followed by a normal L3M2,3M2,3 Auger decay.
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| 9. |
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