Browsing by Author "Yang, HS"

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CPn model on fuzzy sphere
(2002-03-18)
Chan, CT
;
Chen, CM
;
Lin, FL
;
Yang, HS
;
電子物理學系
We construct the CPn model on fuzzy sphere. The Bogomolny bound is saturated by (anti-)self-dual solitons and the general solutions of BPS equation are constructed. The dimension of moduli space describing the BPS solution on fuzzy sphere is exactly the same as that of the commutative sphere or the (noncommutative) plane. We show that in the soliton backgrounds, the number of zero modes of Dirac operator on fuzzy sphere, Atiyah-Singer index, is exactly given by the topological charge of the background solitons. (C) 2002 Elsevier Science B.V. All rights reserved.
Regular and chaotic dynamics of a rotational machine with a centrifugal governor
(1999-05-01)
Ge, ZM
;
Yang, HS
;
Chen, HH
;
Chen, HK
;
機械工程學系
The dynamic behavior of a rotational machine with centrifugal governor which is subjected to two different forms of external disturbance is studied in this paper. The Lyapunov direct method is applied to obtain conditions of stability of the equilibrium points of the system. A codimension one bifurcation analysis for the autonomous system is carried out near the degenerate point. It is found that a Hopf bifurcation occurs in the system. The incremental harmonic balance (IHB) method combined with the multi-variable Floquet theory has been effectively applied to obtain the steady state responses of the three-dimensional nonautonomous system. Phase portraits, power spectra, Poincare maps, and Lyapunov exponents are presented to observe periodic, quasi-periodic and chaotic motions. (C) 1999 Elsevier Science Ltd. All rights reserved.