663 research outputs found
Stator vibration of generator under SAERISC faults
This paper analyzes the stator vibration response under static air-gap eccentricity and rotor inter-turn short circuit composite faults (SAERISC). The detailed formula of the magnetic force on stator is firstly deduced. Then the finite element simulations and practical experiments are taken to investigate the stator vibration response. It’s shown that, 1st to 4th stator vibrations will be produced. The development of the short circuit will decrease the 2nd vibration but increase the 4th vibration, while the increment of the eccentricity will increase the 1st to 4th vibrations at the same time
Half-filled Kondo lattice on the honeycomb lattice
The unique linear density of state around the Dirac points for the honeycomb
lattice brings much novel features in strongly correlated models. Here we study
the ground-state phase diagram of the Kondo lattice model on the honeycomb
lattice at half-filling by using an extended mean-field theory. By treating
magnetic interaction and Kondo screening on an equal footing, it is found that
besides a trivial discontinuous first-order quantum phase transition between
well-defined Kondo insulator and antiferromagnetic insulating state, there can
exist a wide coexistence region with both Kondo screening and antiferromagnetic
orders in the intermediate coupling regime. In addition, the stability of Kondo
insulator requires a minimum strength of the Kondo coupling. These features are
attributed to the linear density of state, which are absent in the square
lattice. Furthermore, fluctuation effect beyond the mean-field decoupling is
analyzed and the corresponding antiferromagnetic spin-density-wave transition
falls into the O(3) universal class. Comparatively, we also discuss the Kondo
necklace and the Kane-Mele-Kondo (KMK) lattice models on the same lattice.
Interestingly, it is found that the topological insulating state is unstable to
the usual antiferromagnetic ordered states at half-filling for the KMK model.
The present work may be helpful for further studies on the interplay between
conduction electrons and the densely localized spins on the honeycomb lattice.Comment: pages, 7 figure,manuscript is heavily expande
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