| 1. |
- Dedic, R, et al.
(författare)
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Hole burning study of cyanobacterial Photosystem II complexes differing in the content of small putative chlorophyll-binding proteins
- 2004
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Ingår i: Journal of Luminescence. - : Elsevier BV. - 0022-2313. ; 107:1-4, s. 230-5
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Tidskriftsartikel (refereegranskat)abstract
- This contribution presents low-temperature absorption, both broad-band and site-selective excited fluorescence, and persistent hole burning spectra of Photosystem II complexes from the Photosystem I-lacking strains of the cyanobacterium Synechocystis sp. PCC 6803 differing in the content of small putative chlorophyll-binding proteins (Scps). These proteins are homologous to light-harvesting complex of higher plants and may bind pigments. The excited state lifetimes of the complexes were determined from zero-phonon hole widths extrapolated to zero-burning dose. The area and spectral position of a phonon side-band with respect to the zero-phonon hole provided additional information concerning chlorophyll–protein coupling and the Stokes shift. Decrease of three absorption subbands at (670.0, 672.9, and 675.7 nm) in the Photosystem II isolated from the strain lacking ScpC and ScpD is in agreement with a hypothesis about the role of Scps in the chlorophyll binding. In addition, narrowing of the zero-phonon hole in Photosystem II without both Scps indicates slowering of the excitation energy transfer which may be explained by the absence of a protective excitation energy quenching related to the presence of Scps.
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| 2. |
- Krlin, L., et al.
(författare)
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Anomalous impurity diffusion in models of tokamak edge plasma turbulence
- 2004
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Ingår i: Czechoslovak Journal of Physics. - 0011-4626 .- 1572-9486. ; 54:1-3, s. 157-163
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Tidskriftsartikel (refereegranskat)abstract
- Using a simple spatially periodical and stationary potential as a model of electrostatic tokamak edge plasma turbulence, we have found recently [1, 2] an anomalous impurity diffusion in this regime. In this contribution, we estimate this diffusion for a more general and realistic form of the potential, which is close to the Hasegawa-Wakatani (HW) potential. As an interesting consequence of the discussed dynamics, we present, possibility of radial electric field generation in the edge turbulence regime. This effect. might play a role in tokamak scenarios with transport barriers.
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| 3. |
- Krlin, L., et al.
(författare)
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Stochastic (E x B) diffusion of ions in a spatially periodical potential field
- 2000
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Ingår i: Physica scripta. T. - 0281-1847. ; T84, s. 221-224
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Tidskriftsartikel (refereegranskat)abstract
- In this contribution, the stochastic (E x B) motion of ions in a homogeneous magnetic field and in a spatially periodical electrostatic potential is discussed. This approach is used for the simulation of ion diffusion in potential structures formed at the boundary plasma in tokamaks. Nonintegrability of the system causes the spatial diffusion of ions. Depending on the choice of parameters, this diffusion has either the usual random-walk character, or appears, for sufficiently strong nonlinearity, in the form of Levy walks. The diffusion coefficient is sufficiently high for heavy impurities. Possible further applications are mentioned.
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