46,288 research outputs found
Electron-hydrogen scattering in Faddeev-Merkuriev integral equation approach
Electron-hydrogen scattering is studied in the Faddeev-Merkuriev integral
equation approach. The equations are solved by using the Coulomb-Sturmian
separable expansion technique. We present - and -wave scattering and
reactions cross sections up to the threshold.Comment: 2 eps figure
Brueckner-Hartree-Fock and its renormalized calculations for finite nuclei
We have performed self-consistent Brueckner-Hartree-Fock (BHF) and its
renormalized theory to the structure calculations of finite nuclei. The
-matrix is calculated within the BHF basis, and the exact Pauli exclusion
operator is determined by the BHF spectrum. Self-consistent occupation
probabilities are included in the renormalized Brueckner-Hartree-Fock (RBHF).
Various systematics and convergences are studies. Good results are obtained for
the ground-state energy and radius. RBHF can give a more reasonable
single-particle spectrum and radius. We present a first benchmark calculation
with other {\it ab initio} methods using the same effective Hamiltonian. We
find that the BHF and RBHF results are in good agreement with other
methods
Predictors of diabetes in older people in urban China.
China has the largest number of people with diabetes in the world. Over the last 30 years China has experienced rapid economic growth and a growing income gap between rich and poor. The population is ageing, however diabetes in older people has not been well studied to date. In this study we determined incidence and predictors of diabetes in older Chinese people
Resonant-state solution of the Faddeev-Merkuriev integral equations for three-body systems with Coulomb potentials
A novel method for calculating resonances in three-body Coulombic systems is
proposed. The Faddeev-Merkuriev integral equations are solved by applying the
Coulomb-Sturmian separable expansion method. The S-state
resonances up to threshold are calculated.Comment: 6 pages, 2 ps figure
Catastrophic eruption of magnetic flux rope in the corona and solar wind with and without magnetic reconnection
It is generally believed that the magnetic free energy accumulated in the
corona serves as a main energy source for solar explosions such as coronal mass
ejections (CMEs). In the framework of the flux rope catastrophe model for CMEs,
the energy may be abruptly released either by an ideal magnetohydrodynamic
(MHD) catastrophe, which belongs to a global magnetic topological instability
of the system, or by a fast magnetic reconnection across preexisting or
rapidly-developing electric current sheets. Both ways of magnetic energy
release are thought to be important to CME dynamics. To disentangle their
contributions, we construct a flux rope catastrophe model in the corona and
solar wind and compare different cases in which we either prohibit or allow
magnetic reconnection to take place across rapidly-growing current sheets
during the eruption. It is demonstrated that CMEs, even fast ones, can be
produced taking the ideal MHD catastrophe as the only process of magnetic
energy release. Nevertheless, the eruptive speed can be significantly enhanced
after magnetic reconnection sets in. In addition, a smooth transition from slow
to fast eruptions is observed when increasing the strength of the background
magnetic field, simply because in a stronger field there is more free magnetic
energy at the catastrophic point available to be released during an eruption.
This suggests that fast and slow CMEs may have an identical driving mechanism.Comment: 7 pages, 4 figures, ApJ, in press (vol. 666, Sept. 2007
Two-photon absorption and broadband optical limiting with bis-donor stilbenes
Large two-photon absorptivities are reported for symmetrical bis-donor stilbene derivatives with dialkylamino or diphenylamino groups. These molecules exhibit strong optical limiting of nanosecond pulses over a broad spectral range in the visible. Relative to bis(di-n-butylamino)stilbene, bis(diphenylamino)stilbene exhibits a 90-nm red shift of its optical limiting band but only a minimal shift of ~13 nm of its lowest one-photon electronic absorption band. Mixtures of these compounds offer an unprecedented combination of broad optical limiting bandwidth and high linear transparency
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