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| 2. |
- Frey, H U, et al.
(författare)
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Freja and ground-based analysis of inverted-V events
- 1998
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Ingår i: JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS. - 0148-0227. ; 103:A3, s. 4303-4314
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Tidskriftsartikel (refereegranskat)abstract
- During two campaigns, ground-based auroral observations were performed in coordination with Freja. The high temporal and spatial resolution of the satellite instruments as well as the real-time recording with a stereoscopic camera system from the ground enabled detailed comparison of small- and large-scale optical phenomena with particle and field data measured by the satellite. Three passes of the satellite over inverted-V auroral arcs and over precipitation regions with strong field-aligned electron spectra are investigated. Brightness modulations within auroral arcs coincide with modulations of primary electron fluxes. The dynamics of small-scale structures within arcs as well as the proper motion of arcs are analyzed and compared with electric fields measured by the satellite and with BARS radar measurements. Energy fluxes independently determined from the ground and from the satellite are used to calculate the field-aligned conductance. The results agree with predictions of the kinetic theory of the mirror force, if we allow for variations of the density and thermal energy of the electrons in the source region of the magnetosphere. Detailed comparison of electron spectra and electric and magnetic field perturbations provide evidence of different acceleration mechanisms for the electrons, electrostatic acceleration inside inverted-V's, and wave acceleration in transient regions.
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| 3. |
- Scheunemann, T, et al.
(författare)
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Quantum well resonances in ferromagnetic Co films
- 1997
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Ingår i: SOLID STATE COMMUNICATIONS. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0038-1098. ; 104:12, s. 787-792
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The above-vacuum-threshold electronic structure of ultrathin Co films on W(110) is studied for coverages from 1 monoatomic layer (ML) upward. For n ML, the spin-dependent layer-projected local density of states (LDOS) for k parallel to = 0, which is calcu
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| 4. |
- Wagner, W, et al.
(författare)
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Europe ambivalent on biotechnology
- 1997
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Ingår i: Nature. - London : Nature Publishing Group. - 0028-0836 .- 1476-4687. ; 387, s. 845-847
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Tidskriftsartikel (refereegranskat)abstract
- The Eurobarometer on Biotechnology (46.1) was conducted during October and November 1996. The survey conducted in each EU (European Union) country used a multi-stage random sampling procedure and provided a statistically representative sample of national residents aged 15 and over. The total sample within the EU was 16,246 respondents (about 1,000 per EU country). The survey questionnaire was designed by the authors as part of a larger study involving the comparative analysis of public perceptions, media coverage and public policy in relation to biotechnology from 1973 to the present.
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| 5. |
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| 6. |
- Bauer, A. D., et al.
(författare)
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Corrosion behaviour of monocrystalline titanium nitride
- 1997
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Ingår i: Surface and Coatings Technology. ; 91:3, s. 208-214
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Tidskriftsartikel (refereegranskat)abstract
- The corrosion behaviour of monocrystalline and highly textured TiN films deposited onto single crystalline MgO has been investigated. It was found that films with high defect concentrations and elements of polycrystallinity had a reduced corrosion resistance. These films had low corrosion potentials and high critical and passive current densities. For high quality films the [110]- and [111]-orientations generally displayed better corrosion properties than films with [100]-orientation. Corrosion had different effects on films of different orientations: On [100]-oriented films loose rectangularly shaped flakes were observed. [110]-oriented films cracked because of compressive stresses, which in many cases caused the films to peel off during corrosion. On [111]-oriented films, finally, triangular pits were detected after corrosion. Films with high corrosion potentials had low values of critical and passive current densities. Non-destructive electrochemical analysis in combination with defect analysis can thus be used to predict the behaviour of these films on anodic polarisation.
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| 8. |
- Einarsdottir, H, et al.
(författare)
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110 subfascial lipomatous tumors. MR and CT findings versus histopathological diagnosis and cytogenetic analysis
- 1999
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Ingår i: Acta radiologica (Stockholm, Sweden : 1987). - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 40:6, s. 603-609
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate whether liposarcoma, atypical lipomatous tumors and lipoma can be differentiated radiologically. Material and Methods: We have retrospectively analyzed CT and/or MR images of 110 subfascial lipomatous lesions. the amount of fat within the tumors was visually graded from the images as: none, 1–75%, 75–95% or 95–100%. the structure of non-fatty tumor components was compared. the images were compared to histopathology and in 37 cases to cytogenetic findings. Results: Only 4 of 20 liposarcomas contained fat. All 4 lesions, histopathologically diagnosed as atypical lipomatous tumors, contained fat but less than 75% of tumor volume. All lesions with more fat than 75% of tumor volume were histologically diagnosed as lipomas. However, one-third of the karyotyped lipomas had ring chromosomes which are considered typical for atypical lipomatous tumors. Conclusion: When a tumor is composed more or less solely of fat, the diagnosis of a lipoma or atypical lipomatous tumor with a phenotype simulating a lipoma can be assumed. When the fat content is less than 75% of the tumor volume or non-fatty nodules are found, biopsies from different tumor components have to be performed to exclude malignancy. When no fat is found, imaging does not help in differentiating lipoma or liposarcoma from other soft tissue tumors.
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| 9. |
- Einarsdottir, H, et al.
(författare)
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MR imaging of lipoma and liposarcoma
- 1999
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Ingår i: Acta radiologica (Stockholm, Sweden : 1987). - : SAGE Publications. - 0284-1851 .- 1600-0455. ; 40:1, s. 64-68
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate whether lipoma, atypical lipomatous tumors, and lipo-sarcomas can be differentiated by MR images. Material and Methods: The MR images of 59 lipomatous lesions and liposarcomas were retrospectively reviewed. Apart from size, surgical site, location and margins, the percentage of fat of the tumor volume was assessed as none, 1-75%, 75-95%, or 95-100%. Results: None of the 18 liposarcomas contained fat that could be recognized by MR imaging. The 3 atypical lipomatous tumors all contained fat but less than 75% of the tumor volume. In 32 of 38 ordinary lipomas, the percentage of fat was 95-100%, and in 4 less than 95% of the tumor volume. Two lipomas did not contain fat that could be recognized by MR imaging. Conclusion: A lesion which predominantly has a fat signal is, in all probability, an ordinary lipoma. Lesions with less fat, but still mostly fatty, may either be lipoma or atypical lipomatous tumor. In this group, the discrimination between these two entities cannot be based upon imaging features. In the absence of a fat signal, liposarcoma or lipoma cannot be differentiated from other soft tissue tumors.
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