When a colloidal suspension is exposed to a strong rotating electric field, an aggregation of the suspended particles is induced to appear. In such clusters, the separation between the suspended particles is so close ...When a colloidal suspension is exposed to a strong rotating electric field, an aggregation of the suspended particles is induced to appear. In such clusters, the separation between the suspended particles is so close that one could not neglect the multiple image effect on the electrorotation (ER) spectrum. Since so far the exact multiple image method exists in two dimensions only, rather than in three dimensions, we investigate the ER spectrum of the clustered colloidal particles in two dimensions, in which many cylindrical particles are randomly distributed in a sheet cluster. We report the dependence of the ER spectrum on the materialparameters. It is shown that the multiple image method predicts two characteristic frequencies, at which the rotation speed reaches maximum. To this end, the multiple image method is numerically demonstrated to be in good agreement with the known Maxwell-Garnett approximation.展开更多
Wave field around Taipei Port is studied. Using marine radar as a monitoring device, sequences of the wave field images were obtained on an hourly basis. A 3D-FFT was applied to the image sequences leading to the so-c...Wave field around Taipei Port is studied. Using marine radar as a monitoring device, sequences of the wave field images were obtained on an hourly basis. A 3D-FFT was applied to the image sequences leading to the so-called intensity wavenumber-frequency spectrum. Wave field information can then be extracted from these spectra and compared with on-site measurements. It is shown that, when the prevailing winds are weak, estimated wave heights agree miserably with those measured. On the other hand, when the winds are relatively strong, our estimates follow closely with the trends, but are, in general, lower than measured. Possible reasons leading to these discrepancies are discussed.展开更多
We study the quantum phase transition of ultracold atoms in the honeycomb optical lattice. The Hamiltonian of ultracold bosonic atoms in the honeycomb optical lattice is derived. We take the mean-field approximation a...We study the quantum phase transition of ultracold atoms in the honeycomb optical lattice. The Hamiltonian of ultracold bosonic atoms in the honeycomb optical lattice is derived. We take the mean-field approximation and further solve the Hamiltonian with the numerical diagonalization method. We obtain the phase diagram and find that the Mort-insulator （MI）, density wave （DW） and modulated superfluid （MS） phases appear. Furthermore, the phase diagram is analyzed according to the order parameter and the average number of particles.展开更多
文摘When a colloidal suspension is exposed to a strong rotating electric field, an aggregation of the suspended particles is induced to appear. In such clusters, the separation between the suspended particles is so close that one could not neglect the multiple image effect on the electrorotation (ER) spectrum. Since so far the exact multiple image method exists in two dimensions only, rather than in three dimensions, we investigate the ER spectrum of the clustered colloidal particles in two dimensions, in which many cylindrical particles are randomly distributed in a sheet cluster. We report the dependence of the ER spectrum on the materialparameters. It is shown that the multiple image method predicts two characteristic frequencies, at which the rotation speed reaches maximum. To this end, the multiple image method is numerically demonstrated to be in good agreement with the known Maxwell-Garnett approximation.
文摘Wave field around Taipei Port is studied. Using marine radar as a monitoring device, sequences of the wave field images were obtained on an hourly basis. A 3D-FFT was applied to the image sequences leading to the so-called intensity wavenumber-frequency spectrum. Wave field information can then be extracted from these spectra and compared with on-site measurements. It is shown that, when the prevailing winds are weak, estimated wave heights agree miserably with those measured. On the other hand, when the winds are relatively strong, our estimates follow closely with the trends, but are, in general, lower than measured. Possible reasons leading to these discrepancies are discussed.
基金Supported by the Teaching and Research Foundation for the Outstanding Young Faculty of Southeast University
文摘We study the quantum phase transition of ultracold atoms in the honeycomb optical lattice. The Hamiltonian of ultracold bosonic atoms in the honeycomb optical lattice is derived. We take the mean-field approximation and further solve the Hamiltonian with the numerical diagonalization method. We obtain the phase diagram and find that the Mort-insulator （MI）, density wave （DW） and modulated superfluid （MS） phases appear. Furthermore, the phase diagram is analyzed according to the order parameter and the average number of particles.
