# Membrane

The MolecularMembrane Physlet is an extension of the MolecularApplet Physlet.  It is part of the molecular dynamics package and is downloaded whenever the Molecular.jar file is specified in the archive tag.  The two ensembles in this applet are connected by a semi-permeable membrane.

The MolecularMembrane Physlet is embedded using the following syntax. The [location] parameter should be the URL of the directory that contains the jar file and the [name] should be a unique variable name by which JavaScript can refer to this applet.s

``` ```

```<applet     CODEBASE=[location]     CODE="molecular.MolecularMembrane.class"     ARCHIVE="Molecular.jar"     NAME=[script_name]     ID=[script_name]>```

```<param name=[par_name] value=[par_Value]> . . </applet>```

The applet that you see on this page was embedded as follows. Notice the probability parameter.  This parameter string represents a function of mass, p(m), that determines the probability of a particle passing through the membrane.  The probability is a constant 10% for all particles in this simulation.  Another simulation shows a mass dependent probability.

``` <applet     CODEBASE="../classes/"     ARCHIVE="Molecular.jar"     CODE="molecular.MolecularMembrane.class"     NAME="Molecular" ID="Molecular"     WIDTH="300"     HEIGHT="300"     HSPACE="0"     VSPACE="0"     ALIGN="middle"> <param name="ShowControls" value="true"> <param name="InitialP" value="10"> <param name="FPS" value="50"> <param name="dt" value="0.05"> <param name="PeriodicV" value="true"> <param name="PixPerUnit" value="10"> <param name="PistonMass" value="10"> <param name="MaxParticles" value="80"> <param name="Probability" value="0.1"> </applet> <\code> ```