Biomedical subjects

Peilong Chen

Publications and source records attributed to Peilong Chen.

4 recordsLinked to original sources

PubMed2005

Mean-field theory for inhomogeneous electrolytes.

We calculate the free energy density for inhomogeneous electrolytes based on the mean-field Debye-Hückel theory. Derived are the contributions of (1) the differential term for the electrolyte density being slow varying in one direction and (2) the boundary term for an electrolyte confined to one side of a planar interface. These contributions are shown to cause an electrolyte depletion near the air-water interfaces, which makes the surface tension increase, to be significantly larger than those predicted by previous theories. Nonuniform electrolyte densities are also computed near the water-electrolyte and electrolyte-electrolyte interfaces. Finally we calculate the interaction of two uncharged macrospheres due to the electrolyte depletion.

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PubMed2005

Shear alignments in three-dimensional simulations of lamellar phases.

Experiments studying layer orientation of sheared lamellar phases have consistently observed not only the seemingly obvious parallel orientation (with layers parallel to the shear plane), but also the so called perpendicular orientation (with layer normals along the vorticity direction) at the condition of higher shear frequencies and near the lamellar phase transition. We find that three-dimensional simulations of a deterministic mesoscopic dynamical equation (without thermal fluctuations) under the convection of simple shear flows have shown exactly such a dependence. The simulations show the important role played by the transverse orientation (layer normal along the velocity direction) and highlight the mechanism of the shear alignment being the competition between the shear frequency and the mesoscopic time scale of pattern organization.

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PubMed2004

Measurement of mean flows of Faraday waves.

We measure the velocities of the mean flows that are driven by curved rolls in a pattern formation system. Curved rolls in Faraday waves are generated in experimental cells consisting of channels with varying widths. The mean flow magnitudes are found to scale linearly with roll curvatures and squares of wave amplitudes, agreeing with the prediction from the analysis of phase dynamics expansion. The effects of the mean flows on reducing roll curvatures are also seen.

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PubMed2002

Nonlinear wave dynamics in Faraday instabilities.

Nonlinear wave dynamics in parametrically driven surface waves are studied in numerical simulations of the two-dimensional Navier-Stokes equation, with an emphasis on the evolution and interaction between different wave number modes. The dynamics are found to be closely correlated with the single-mode nonlinear saturated wave amplitudes. Modulating behavior of primary wave modes in a particular parameter range and in time scales much longer than the underlining wave periods is observed.

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