Difference between revisions of "Brownian Dynamics of a Sphere Between Parallel Walls"
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To the right is a diagram showing my best interpretation of the apparatus the authors used to make high resolution measurements of the brownian motion of a sphere confined along one dimension by two glass planes 8 microns apart. They positioned a 1 micron sphere in a precise position using an optical trap, then released it to study motion. They imaged with a video microscope at 60 Hz and used particle centroiding to obtain a resolution of 20 nm in x and y. They obtained z information by repeating the experiment releasing the particle from the same location with the microscope focused at differing heights. They measure distance from the wall by running a steady poiseuille flow and observing its effect on the particle velocity. | To the right is a diagram showing my best interpretation of the apparatus the authors used to make high resolution measurements of the brownian motion of a sphere confined along one dimension by two glass planes 8 microns apart. They positioned a 1 micron sphere in a precise position using an optical trap, then released it to study motion. They imaged with a video microscope at 60 Hz and used particle centroiding to obtain a resolution of 20 nm in x and y. They obtained z information by repeating the experiment releasing the particle from the same location with the microscope focused at differing heights. They measure distance from the wall by running a steady poiseuille flow and observing its effect on the particle velocity. | ||
| − | [[Image:fig1.png|thumb|left|400px|Fig 1: " (a) Measured probability distribution for displacements along the direction of flow at | + | [[Image:dufresne.epl.2001-fig1.png|thumb|left|400px|Fig 1: " (a) Measured probability distribution for displacements along the direction of flow at t = |
1/60 s and 4/60 s for z = 4 μm. The solid curves are fits to eq. (3) for the width and displacement | 1/60 s and 4/60 s for z = 4 μm. The solid curves are fits to eq. (3) for the width and displacement | ||
of the distribution. (b) Drift of the distributions’ centers along and perpendicular to the direction of | of the distribution. (b) Drift of the distributions’ centers along and perpendicular to the direction of | ||
the imposed flow. (c) Evolution of the mean-square widths of P (ri , τ |z), fit to eq. (1) for Di (h)."]] | the imposed flow. (c) Evolution of the mean-square widths of P (ri , τ |z), fit to eq. (1) for Di (h)."]] | ||
Revision as of 00:41, 21 September 2010
Original Entry by Tom Dimiduk, AP225 Fall 2010
Brownian Dynamics of a Sphere Between Parallel Walls E. R. Dufresne, D. Altman and D. G. Grier
Soft matter Keywords
Brownian Motion, Surface
Summary
To the right is a diagram showing my best interpretation of the apparatus the authors used to make high resolution measurements of the brownian motion of a sphere confined along one dimension by two glass planes 8 microns apart. They positioned a 1 micron sphere in a precise position using an optical trap, then released it to study motion. They imaged with a video microscope at 60 Hz and used particle centroiding to obtain a resolution of 20 nm in x and y. They obtained z information by repeating the experiment releasing the particle from the same location with the microscope focused at differing heights. They measure distance from the wall by running a steady poiseuille flow and observing its effect on the particle velocity.
