4,721 research outputs found
The importance of nuclear masses in the astrophysical rp-process
The importance of mass measurements for astrophysical capture processes in
general, and for the rp-process in X-ray bursts in particular is discussed. A
review of the current uncertainties in the effective lifetimes of the major
waiting points 64Ge, 68Se, and 72Kr demonstrates that despite of recent
measurements uncertainties are still significant. It is found that mass
measurements with an accuracy of the order of 10 keV or better are desirable,
and that reaction rate uncertainties play a critical role as well.Comment: 14 pages, 4 figures, to appear in International Journal of Mass
Spectroscop
Neutron Capture in the keV Energy Range in Structural Materials for Fast Reactors. Proceedings of a NEACRP/NEANDC Specialist Meeting, held in May 1973 at the Kernforschungszentrum Karlsruhe
The Influence of Reaction Rates on the Final p-Abundances
The astrophysical p-process is responsible for the origin of the proton rich
nuclei,which are heavier than iron. A huge network involving thousands of
reaction rates is necessary to calculate the final p-abundances. But not all
rates included in the network have a strong influence on the p-nuclei
abundances. The p-process was investigated using a full nuclear reaction
network for a type II supernovae explosion when the shock front passes through
the O/Ne layer. Calculations were done with a multi-layer model adopting the
seed of a pre-explosion evolution of a 25 mass star. In extensive simulations
we investigated the impact of single reaction rates on the final p-abundances.
The results are important for the strategy of future experiments in this field.Comment: 4 page
Oxygen-Evolving Extracts from a Thermophilic Cyanobacterium Synechococcus sp.
Spheroplast membranes of a thermophilic cyanobacterium Synechococcus sp. have been treated with the detergent lauryldim ethylam ine oxide (LDAO). The resulting extracts show (1) light-induced O2 evolution with artificial electron acceptors, (2) four-fold enhancement of the O2 evolution relative to chlorophyll, (3) parallel increase of both the molar ratios of PS 2/C hl and cyt b559/Chl in the extract, (4) dissociation of the auxiliary pigment phycocyanin upon treatment with LDAO, but still tight association of allophycocyanin to the photosystem 2 preparation
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