A method of controlling an etching process for forming an epitaxial structure includes the following steps. Some examples of the two sections of the container that can be assembled and disassembled utilizing the correlated magnets include a wall panel, top panel, side panel, bottom panel, door panel, a handle, a tool, a belt, a frame member or locking member. The crystalline calcium carbonate can be calcite that has been specially modified to a rhombohedral crystal structure with 1,0-1,1 indices. In the parking brake function the friction element of the first wheel brake, by utilizing the wedge face used to boost the force in braking operations during forward travel, and the friction element of the second wheel brake, by utilizing the wedge face used to boost the force in braking operations during reverse travel, are clamped against the component of the wheel brake that is to be braked. The control unit receives the control information in wireless fashion. The first voltage is not greater than the second voltage.