93,733 research outputs found
The brightness temperature of the air-sea interface at microwave frequencies
Available results of observation have shown that at nadir the brightness temperature of the sea surface at 19.35 GHz increases linearly with increasing wind speed. The computational results of the modified theoretical model presented are in good agreement with the measurement results both at nadir and other angles. The model depicts that, for a fully developed sea driven by the wind with speed above 5 m/sec, the air in the transitional zone immediately above the air-sea interface is mixed with sea water droplets from bursting air bubbles. The droplet concentration has a profile tapering off to zero at a certain height. The dielectric constant of the inhomogeneous droplet profile is thus both a function of the height above the interface and the wind speed. Both the inhomogeneity effect and the possible attenuation effect of the droplet concentration have been considered
The effects of latent heat release on the waves with Ekman pumping
The problem of the effects of the latent heat release on the waves with both upper and lower boundary frictional effects is investigated. The influence of the vertical shear of the basic wind in these models will be investigated. These investigations will shed some light on the method of solution to the problem of including the effect of Ekman pumping on the moist baroclinic waves in the model of Tang and Fichtl
Spin content of Lambda and its longitudinal polarization in annihilation at high energies
Longitudinal polarization of Lambda produced in annihilation at LEP
energies is calculated in a picture for the spin content of Lambda which is
consistent with the polarized deep inelastic lepton-nucleon scattering data and
SU(3) flavor symmetry for hyperon decay so that the spin of Lambda is not
completely carried by its -valence quark. A comparison with the recent ALEPH
data and the results of earlier calculations based on the static quark model in
which the spin of Lambda is completely determined by the -quark is given.
The result shows that further measurements of such polarization should provide
useful information to the question of which picture is more suitable in
describing the spin effects in the fragmentation processes.Comment: 12 pages, 2 figure
Single spin asymmetries in inclusive high energy hadron-hadron collision processes
It has been realized for quite a long time that single-spin experiments, in
which one of the colliding objects is transversely polarized, can be helpful in
studying the properties of strong interaction in general and in testing Quantum
Chromodynamics (QCD) in particular.
Striking effects have been observed in the past few years which deviate
drastically from the expectation of the perturbative QCD parton model.
These effects have received much attention.
New experiments of the similar type are underway and/or planned.
Different theoretical attempts have been made to understand these effects.
In this review, the special role played by singly polarized high-energy
hadron-hadron collisions in High Energy Spin Physics is emphasized.
Characteristics of the available data for inclusive hadron productions are
briefly summarized.
Different theoretical approaches for such processes are reviewed with special
attention to a non-perturbative model which explicitly takes the orbital motion
of the valence quarks and hadronic surface effects into account.
The connection between such asymmetries and hyperon polarization in
unpolarized reactions is discussed.
An example of the possible application of such experimental results in other
processes is given.Comment: 62 pages, 17 ps-figures (Review article to appear in Inter. J. Mod.
Phys. A
- …