31,875 research outputs found
Electron multiplier development /phase 1/
Fabrication of aluminum oxide thin film window for capillary type photomultiplier tube
Base reaction optimization of redundant manipulators for space applications
One of the problems associated with redundant manipulators which were proposed for space applications is that the reactions transmitted to the base of the manipulator as a result of the motion of the manipulator will cause undesirable effects on the dynamic behavior of the supporting space structure. It is therefore necessary to minimize the magnitudes of the forces and moments transmitted to the base. It is shown that kinematic redundancy can be used to solve the dynamic problem of minimizing the magnitude of the base reactions. The methodology described is applied to a four degree-of-freedom spatial manipulator with one redundant degree-of-freedom
Effective nucleon-nucleon interactions and nuclear matter equation of state
Nuclear matter equations of state based on Skyrme, Myers-Swiatecki and
Tondeur interactions are written as polynomials of the cubic root of density,
with coefficients that are functions of the relative neutron excess .
In the extrapolation toward states far away from the standard one, it is shown
that the asymmetry dependence of the critical point ()
depends on the model used. However, when the equations of state are fitted to
the same standard state, the value of is almost the same in Skyrme
and in Myers-Swiatecki interactions, while is much lower in Tondeur
interaction. Furthermore, does not depend sensitively on the choice
of the parameter in Skyrme interaction.Comment: 15 pages, 9 figure
Nuclear matter properties and relativistic mean-field theory
Nuclear matter properties are calculated in the relativistic mean field
theory by using a number of different parameter sets. The result shows that the
volume energy and the symmetry energy are around the acceptable
values 16MeV and 30MeV respectively; the incompressibility is
unacceptably high in the linear model, but assumes reasonable value if
nonlinear terms are included; the density symmetry is around for
most parameter sets, and the symmetry incompressibility has positive sign
which is opposite to expectations based on the nonrelativistic model. In almost
all parameter sets there exists a critical point , where
the minimum and the maximum of the equation of state are coincident and the
incompressibility equals zero, falling into ranges
0.014fmfm and ; for a few
parameter sets there is no critical point and the pure neutron matter is
predicted to be bound. The maximum mass of neutron stars is predicted
in the range 2.45MM, the corresponding
neutron star radius is in the range 12.2kmkm.Comment: 10 pages, 5 figure
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