A spraying apparatus is disclosed for spraying coating material onto an internal wall of a cylindrical structure having an opening. The lower temperature slurry may be added to the heater vessel in an intermittent or continuous manner, with addition of the lower temperature slurry being regulated by a valve, the operation of which is controlled by a control device which receives temperature information from one or more temperature sensors. Due to such a structure, it is not necessary to perform such a very difficult step that processes the resistance-change material and the silicons collectively and it is possible to provide the memory cell array with a simpler process. The processor further includes two inlet ports for receiving solid material, and an outlet or discharge port for exiting the reduced solid material. In a method of extending or retracting the truck bed, a single truck can be used to mount or remove truck boxes of different sizes.