| 1. |
- Almqvist, Nils, et al.
(författare)
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AFM and STM characterization of surfaces exposed to high flux deuterium plasma
- 1995
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 220-222:1-3, s. 917-921
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Tidskriftsartikel (refereegranskat)abstract
- This paper reports the results of scanning tunneling (STM) and atomic force microscopy (AFM) studies of D+ irradiated graphite and graphite-silicon mixtures. The microscopes were used for studying surface topography and for measuring the surface roughness. The substrates were exposed at various temperatures (60 and 700°C) to different doses of deuterium ions in simulators of plasma - surface interactions and in the TEXTOR tokamak. Also nuclear reaction analysis (NRA) and Rutherford backscattering spectroscopy were applied for the qualitative and quantitative determination of surface composition. The initial stages of radiation damage, nanometer-sized bubbles/blisters, were found in plasma-eroded surfaces. These structures only appeared in the graphite phase on the multicomponent material. The microroughness of the surfaces was measured. We also used the AFM for probing the thickness of the plasma-modified layers. The results correlate with the presence of deuterium measured by NRA depth-profiling. Moreover, the AFM reveals the co-deposited layers formed on surfaces facing the tokamak plasma. The appearance of these layers is clearly correlated to the amount of co-deposited atoms.
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| 2. |
- Almqvist, Nils, et al.
(författare)
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Imaging human erythrocyte spectrin with atomic force microscopy
- 1994
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Ingår i: Micron. - : Elsevier BV. - 0968-4328 .- 1878-4291. ; 25:3, s. 227-232
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Tidskriftsartikel (refereegranskat)abstract
- Isolated spectrin covalently attached to a surface in a liquid environment as well as dried on mica has been studied with a contact-mode atomic force microscope. Both pyramidal and conical-type cantilever tip facets were used in the AFM. Our images show structures and give dimensions that correlate well with previous structural studies using transmission electron microscopy.
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| 3. |
- Almqvist, Nils, et al.
(författare)
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Roughness determination of plasma-modified surface layers with atomic force microscopy
- 1995
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 270:1-2, s. 426-430
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Tidskriftsartikel (refereegranskat)abstract
- Graphite surfaces exposed to the deuterium plasma in the TEXTOR tokamak were characterized in detail by means of scanning probe microscopy, ion beam analysis and colorimetry methods. The aim is to study the composition and structure of thin layer deposits formed on surfaces subjected to the tokamak plasma. The surface roughness was measured and parametrized in terms of fractal dimension and scaling constant. Several different methods for the fractal analysis of plasma-exposed surfaces have been critically evaluated. The main emphasis of this paper is on the correlation between surface roughness (fractal parameters), the amount of deposited atoms and the layer thickness.
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| 4. |
- Almqvist, Nils, et al.
(författare)
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Scanning probe microscopy and thermo-mechanical characterization of silicon carbide composites
- 1995
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Ingår i: Fourth Euro-Ceramics. - : Gruppo Ed. Faenza Ed.. - 8881380072 ; , s. 361-368
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Konferensbidrag (refereegranskat)abstract
- series of SiC-based composites was obtained by sintering. Since such materials are considered for fusion applications, their thermal shock resistance and behaviour under deuterium irradiation are of primary interest. Extensive bulk and surface characterisation of pure and doped (AlN, TiB2, graphite) silicon carbides treated by a deuterium plasma was carried out. The change in surface structure following irradiation is addressed, and major factors influencing deuterium retention are discussed.
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| 5. |
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| 6. |
- Anoushirvani, B., et al.
(författare)
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Gamma-ray bursts from primordial quark objects in space
- 1997
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Ingår i: Proceedings of the Joint Meeting of the Networks 'The Fundamental Structure of Matter' and 'Tests of the Electroweak Symmetry Breaking', Ouranoupolis, Greece, May 1997.
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Konferensbidrag (refereegranskat)abstract
- We investigate the possibility that gamma-ray bursts originate in a concentric spherical shell with a given average redshift and find that this is indeed compatible with the data from the third BATSE (3B) catalog. It is also shown that there is enough freedom in the choice of unknown burst properties to allow even for extremely large distances to the majority of bursts. Therefore, we speculate about an early, and very energetic, origin of bursts, and suggest that they come from phase transitions in massive objects of pure quark matter, left over from the Big Bang.
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| 7. |
- Anselmino, Mauro, et al.
(författare)
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Diquarks
- 1993
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Ingår i: Reviews of Modern Physics. - 0034-6861 .- 1539-0756. ; 65:4, s. 1199-1233
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Tidskriftsartikel (refereegranskat)abstract
- It is becoming increasingly clear that the concept of a diquark (a two-quark system) is important for understanding hadron structure and high-energy particle reactions. According to our present knowledge of quantum chromodynamics (QCD), diquark correlations arise in part from spin-dependent interactions between two quarks, from quark radial or orbital excitations, and from quark mass differences. Diquark substructures affect the static properties of baryons and the mechanisms of baryon decay. Diquarks also play a role in hadron production in hadron-initiated reactions, deep-inelastic lepton scattering by hadrons, and in e+e- reactions. Diquarks are important in the formation and properties of baryonium and mesonlike semistable states. Many spin effects observed in high-energy exclusive reactions pose severe problems for the pure quark picture of baryons and might be explained by the introduction of diquarks as hadronic constituents. There is considerable controversy, not about the existence of diquarks in hadrons, but about their properties and their effects. In this work a broad selection of the main ideas about diquarks is reviewed.
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| 8. |
- Bergström, Lars, et al.
(författare)
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Backward production on nuclei and the tube model
- 1980
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Ingår i: Physical Review D. Particles and fields. - 0556-2821 .- 1089-4918. ; 21:1, s. 305-307
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that the recent data from Burke et al. on backward production in 200-GeV/c nA collisions are in good agreement with expectations from the collective tube model with tube fragmentation taken into account.
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| 9. |
- Bergström, Lars, et al.
(författare)
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Estimates of recoil nucleon spectra in high-energy hadron-nucleus collisions
- 1977
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 68:2, s. 177-179
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that recent data on the recoil nucleon spectrum in 10.5 GeV/c pion-neon collisions are in excellent agreement with a parameter free estimate from the so called tube model for high-energy hadron-nucleus collisions. A simple independent collision model is also treated.
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| 10. |
- Bergström, Lars, et al.
(författare)
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Is the recently published counterproof of the tube model credible?
- 1978
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 78:2-3, s. 337-341
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that recent data from pion and proton collision with emulsion nuclei at 200 GeV/c are in perfect agreement with expectations from the collective tube model. The opposite conclusion in publications by Azimov et al. came about because the authors ignored the important effects of target fragmentation.
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