Boundary control of two PDE's separated by interface conditions

This paper discusses the null boundary controllability of two PDE's modeling a composite solid with different physical properties in each layer.The problem is described by a one dimensional space equation in divergence form, which models different phenomena in a composite solid. These phenomena may be governed - at same time t -, for instance, by the heat equation in one layer and by the Schroedinger equation in the other one. Interface conditions are imposed.