14,656 research outputs found
The Semileptonic Decay Fraction of B Mesons in the Light of Interfering Amplitudes
Consequences of the interference between spectator amplitudes for the
lifetimes and semileptonic decay fractions of B^0 and B^+ mesons are discussed.
Assuming duality and constructive interference between spectator amplitudes we
are able to explain the low experimental value for the semileptonic decay
fraction of mesons. Extracting these amplitudes from a fit to 11 exclusive
hadronic B decay fractions we find
a_1 = 1.05 +/- 0.03 +/- 0.10,
a_2 =+0.227 +/ 0.012 +/- 0.022,
an inclusive semileptonic decay fraction of
(11.2 +/- 0.5 +/- 1.7),
and a lifetime ratio
tau(B^+) / tau(B^0) = 0.83 +/- 0.01 +/- 0.01.Comment: 9 page
Transient electromagnetic interaction of the moon with the solar wind
Transient response of moon to variations in interplanetary magnetic fiel
The early despinning of the sun
Despinning of sun when passing through T Tauri stage during earlier developmen
A theory for the interpretation of lunar surface magnetometer data
Electromagnetic interaction of moon with spatial irregularities in interplanetary magnetic field
The state space of short-range Ising spin glasses: the density of states
The state space of finite square and cubic Ising spin glass models is
analysed in terms of the global and the local density of states. Systems with
uniform and gaussian probability distribution of interactions are compared.
Different measures for the local state density are presented and discussed. In
particular the question whether the local density of states grows exponentially
or not is considered. The direct comparison of global and local densities leads
to consequences for the structure of the state space.Comment: 18 pages (including 6 figures); submitted to Z.f.Physik
Endurance test and evaluation of alkaline water electrolysis cells
Utilization in the development of multi-kW low orbit power systems is discussed. The following technological developments of alkaline water electrolysis cells for space power application were demonstrated: (1) four 92.9 cm2 single water electrolysis cells, two using LST's advanced anodes and two using LST's super anodes; (2) four single cell endurance test stands for life testing of alkaline water electrolyte cells; (3) the solid performance of the advanced electrode and 355 K; (4) the breakthrough performance of the super electrode; (5) the four single cells for over 5,000 hours each significant cell deterioration or cell failure. It is concluded that the static feed water electrolysis concept is reliable and due to the inherent simplicity of the passive water feed mechanism coupled with the use of alkaline electrolyte has greater potential for regenerative fuel cell system applications than alternative electrolyzers. A rise in cell voltage occur after 2,000-3,000 hours which was attributed to deflection of the polysulfone end plates due to creepage of the thermoplastic. More end plate support was added, and the performance of the cells was restored to the initial performance level
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