76,431 research outputs found
Domain wall propagation due to the synchronization with circularly polarized microwaves
Finding a new control parameter for magnetic domain wall (DW) motion in
magnetic nanostructures is important in general and in particular for the
spintronics applications. Here, we show that a circularly polarized magnetic
field (CPMF) at GHz frequency (microwave) can efficiently drive a DW to
propagate along a magnetic nanowire. Two motion modes are identified: rigid-DW
propagation at low frequency and oscillatory propagation at high frequency.
Moreover, DW motion under a CPMF is equivalent to the DW motion under a uniform
spin current in the current perpendicular to the plane magnetic configuration
proposed recently by Khvalkovskiy et al. [Phys. Rev. Lett. 102, 067206 (2009)],
and the CPMF frequency plays the role of the current
Search for and states in the annihilations
Productions and decays of spin-singlet wave charmonium states,
and , in the annihilations are
considered in the QCD multipole expansion with neglecting nonlocality in time
coming from the color-octet intermediate states. Our approximation is opposite
to the Kuang-Yan's model. The results are , , keV
and keV.Comment: LaTeX file, to appear in Phys. Rev.
On weighted time optimal control for linear hybrid automata using quantifier elimination
This paper considers the optimal control problem for linear hybrid automata. In particular, it is shown that the problem can be transformed into a constrained optimization problem whose constraints are a set of inequalities with quantifiers. Quantifier Elimination (QE) techniques are employed in order to derive quantifier free inequalities that are linear. The optimal cost is obtained using linear programming. The optimal switching times and optimal continuous control inputs are computed and used in order to derive the optimal hybrid controller. Our results areapplied to an air traffic management example
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