Urgent research problem: How to solve PDE systems( 2 PDEs 2 unknown u1,u2 coupled in 2 PDEs) in Comsol 4.0????

1.Each PDE is composed of u1,u2.
How to set up the coupling process?

2. The spatial dependence for this problem can be reduced to 1D. du/dx
But it is a 2D rectangle.
The laplcian operator will also consider another dimension(du/dx+du/dy).
We want y dependency vanished.
How to deal with this issue?

THANK YOU VERY MUCH to get a little help.

Best Regards