Dynamics of a deformable self-propelled particle under external forcing

We investigate dynamics of a self-propelled deformable particle under external field in two dimensions based on the model equations for the center of mass and a tensor variable characterizing deformations. We consider two kinds of external force. One is a gravitational-like force which enters additively in the time-evolution equation for the center of mass. The other is an electric-like force supposing that a dipole moment is induced in the particle. This force is added to the equation for the deformation tensor. It is shown that a rich variety of dynamics appears by changing the strength of the forces and the migration velocity of self-propelled particle

Evidence for MBM_B and MCM_C phases in the morphotropic phase boundary region of (1−x)[Pb(Mg1/3Nb2/3)O3]−xPbTiO3(1-x)[Pb(Mg_{1/3}Nb_{2/3})O_3]-xPbTiO_3 : A Rietveld study

We present here the results of the room temperature dielectric constant measurements and Rietveld analysis of the powder x-ray diffraction data on $(1-x)[Pb(Mg_{1/3}Nb_{2/3})O_3]-xPbTiO_3$(PMN-$x$PT) in the composition range $0.20 \leq x \leq 0.45$ to show that the morphotropic phase boundary (MPB) region contains two monoclinic phases with space groups Cm (or $M_B$ type) and Pm (or $M_C$ type) stable in the composition ranges $0.27 \leq x \leq 0.30$ and $0.31 \leq x \leq 0.34$, respectively. The structure of PMN-$x$PT in the composition ranges $0 \leq x \leq$ 0.26, and $0.35 \leq x \leq1$ is found to be rhombohedral (R3m) and tetragonal (P4mm), respectively. These results are compared with the predictions of Vanderbilt & Cohen's theory.Comment: 20 pages, 11 pdf figure

Electromigration-Induced Flow of Islands and Voids on the Cu(001) Surface

Electromigration-induced flow of islands and voids on the Cu(001) surface is studied at the atomic scale. The basic drift mechanisms are identified using a complete set of energy barriers for adatom hopping on the Cu(001) surface, combined with kinetic Monte Carlo simulations. The energy barriers are calculated by the embedded atom method, and parameterized using a simple model. The dependence of the flow on the temperature, the size of the clusters, and the strength of the applied field is obtained. For both islands and voids it is found that edge diffusion is the dominant mass-transport mechanism. The rate limiting steps are identified. For both islands and voids they involve detachment of atoms from corners into the adjacent edge. The energy barriers for these moves are found to be in good agreement with the activation energy for island/void drift obtained from Arrhenius analysis of the simulation results. The relevance of the results to other FCC(001) metal surfaces and their experimental implications are discussed.Comment: 9 pages, 13 ps figure

Potential mainland Chinese cruise travelers’ expectations, motivations, and intentions

The global cruise industry is the fastest growing sector in the entire leisure market. Due to the limited development of the Chinese cruise sector and government controls on outbound travel, the cruise, especially the outbound cruise, is a new concept in China. Few studies have addressed Chinese consumers’ perceptions of cruises. This study aimed to explore the preferences of potential Chinese cruisers and their expectations, motivations, and intentions in relation to taking an outbound cruise. This study also proposed and tested a conceptual framework: the Expectation, Motivation, and Intention (EMI) Model. Data were collected in Beijing and Shanghai; 242 valid responses were received. The results partially supported the proposed model. The theoretical and practical contributions of the study are discussed

Coherent states for exactly solvable potentials

A general algebraic procedure for constructing coherent states of a wide class of exactly solvable potentials e.g., Morse and P{\"o}schl-Teller, is given. The method, {\it a priori}, is potential independent and connects with earlier developed ones, including the oscillator based approaches for coherent states and their generalizations. This approach can be straightforwardly extended to construct more general coherent states for the quantum mechanical potential problems, like the nonlinear coherent states for the oscillators. The time evolution properties of some of these coherent states, show revival and fractional revival, as manifested in the autocorrelation functions, as well as, in the quantum carpet structures.Comment: 11 pages, 4 eps figures, uses graphicx packag

A novel approach to circuit-field-torque coupled time stepping finite element modeling of electric machines

This paper presents a sub-block algorithm for the time stepping finite element solution of problems in which sets of electromagnetic field equations, circuit equations and mechanical equation are coupled together. The proposed method ensures that identical solutions are obtained for the sub-blocks by controlling the step size of the time stepping process. This new method simplifies the process of dealing with coupled-system problems and it also greatly reduces the computation time. A time stepping finite element model of an induction motor is used to demonstrate the proposed method in details.Department of Electrical EngineeringIndustrial CentreAuthor name used in this publication: S. L. HoAuthor name used in this publication: W. N. FuAuthor name used in this publication: H. C. WongH.C. Wong, Industrial Centr