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| 2. |
- Ahrens, J, et al.
(författare)
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Intermediate resonance excitation in the gamma p -> p pi(0)pi(0) reaction
- 2005
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 624:3-4, s. 173-180
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Tidskriftsartikel (refereegranskat)abstract
- The helicity dependence of the total cross section for the (gamma) over right arrow(p) over right arrow -> p pi(0)pi(0) reaction has been measured for the first time at incident photon energies from 400 to 800 MeV. The measurement, performed at the tagged photon beam facility of the MAMI accelerator in Mainz, used the large acceptance detector DAPHNE and a longitudinally polarized frozen-spin target. This channel is found to be excited predominantly when the photon and proton have a parallel spin orientation, most likely due to the intermediate production of the D-13(1520) resonance. However, the contribution of the antiparallel spin configuration, arising from other reaction mechanisms, is also not negligible. This result gives important new information to resolve the existing model discrepancies in the identification of the nucleon resonances contributing to this channel.
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| 3. |
- Dutz, H, et al.
(författare)
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Measurement of helicity-dependent photoabsorption cross sections on the neutron from 815 to 1825 MeV
- 2005
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Ingår i: Physical Review Letters. - 1079-7114. ; 94
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Tidskriftsartikel (refereegranskat)abstract
- Helicity-dependent total photoabsorption cross sections on the deuteron have been measured for the first time at ELSA (Bonn) in the photon energy range from 815 to 1825 MeV. Circularly polarized tagged photons impinging on a longitudinally polarized LiD target have been used together with a highly efficient 4 pi detector system. The data around 1 GeV are not compatible with predictions from existing multipole analyses. From the measured energy range an experimental contribution to the GDH integral on the neutron of [33.9 +/- 5.5(stat)+/- 4.5(syst)] mu b is extracted.
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| 4. |
- Savina, Irina, et al.
(författare)
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Cryogels from poly(2-hydroxyethyl methacrylate): macroporous, interconnected materials with potential as cell scaffolds
- 2007
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-6848 .- 1744-683X. ; 3:9, s. 1176-1184
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Tidskriftsartikel (refereegranskat)abstract
- Macroporous hydrogels (MHs) have been prepared by cross-linking polymerization of hydroxyethyl methacrylate (HEMA) or cross-linking co-polymerization of HEMA with dimethylacrylamide (DMAA) in semi-frozen state. The MHs are elastic and have a unique structure of large interconnected pores with pore sizes up to 100 µm and total porosity of 94–97%, as demonstrated by micro-computed tomography. The stiffness of such MHs increased with total monomer concentration and with the ratio of DMAA in the composition. Pore-surface modification of the HEMA MHs was achieved by grafting a stimuli-responsive polymer, poly(N-isopropylacrylamide) (PNIPAM), with high density using atom transfer radical polymerization (ATRP). The effect of catalytic system, initiator content and the addition of sacrificial initiator on the ATRP process have been studied. The elasticity, possibility of drying and fast re-swelling, tunable mechanical properties and the macroporous, interconnected structure of HEMA MHs are of interest for biomedical applications such as cell culturing.
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