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Wei-Mou Zheng

Publications and source records attributed to Wei-Mou Zheng.

25 records · Page 2Linked to original sources
arXiv2001

Self-Organizing Approach for Finding Borders of DNA Coding Regions

A self-organizing approach is proposed for gene finding based on the model of codon usage for coding regions and positional preference for noncoding regions. The symmetry between the direct and reverse coding regions is adopted for reducing the number of parameters. Without requiring prior training, parameters are estimated by iteration. By employing the window sliding technique and likelihood ratio, a very accurate segmentation is obtained.

physics.bio-ph↗
arXiv1999

Symbolic Dynamics of the Diamagnetic Kepler Problem Without Involving Bounces

Without involving bounce events, a Poincaré section associated with the axes is found to give a map on the annulus for the diamagnetic Kepler problem. Symbolic dynamics is then established based on the lift of the annulus map. The correspondence between the coding derived from this axis Poincaré section is compared with the coding based on bounces. Symmetry is used to reduce the symbolic dynamics. By means of symbolic dynamics the admissibility of periodic orbits is analyzed, and the symmetry of orbits discussed.

chao-dyn↗
arXiv1999

Nonperiodic Orbit Sums in Weyl's Expansion for Billiards

Weyl's expansion for the asymptotic mode density of billiards consists of the area, length, curvature and corner terms. The area term has been associated with the so-called zero-length orbits. Here closed nonperiodic paths corresponding to the length and corner terms are constructed.

quant-ph↗
arXiv1998

Temperature-Dependent Frequency Shifts in Collective Excitations of a Bose-Einstein Condensate

By including the contribution of the thermal cloud to the Lagrangian of the condensate of a Bose gas, we extend the time-dependent variational method at zero temperature to study temperature-dependent low collective excitation modes. A Gaussian trial wave function of the condensate and a static distribution density of the thermal cloud are used, and analytical expressions for temperature-dependent excitation frequencies obtained. Theoretical results are compared with measurements in the JILA and MIT experiments.

cond-mat↗
arXiv1996

The Energy of a Trapped Interacting Bose Gas

A Bose gas in an external potential is studied by means of the semi-classical approximation. Analytical results are derived for the energy of an interacting Bose gas in a generic power-law trapping potential. An expression for the chemical potential below the critical temperature is also obtained. The theoretical results are in qualitative agreement with a recent energy measurement.

cond-mat.stat-mech↗
arXiv1996

Thermodynamic Properties of a Trapped Interacting Bose Gas

A Bose gas in an external potential is studied by means of the local density approximation. Analytical results are derived for the thermodynamic properties of an ideal Bose gas in a generic power-law trapping potential, and their dependence on the mutual interaction of atoms in the case of a non-ideal Bose gas.

cond-mat.stat-mech↗