A graphene layer is formed on a crystallographic surface having a non-hexagonal symmetry. The access point transmits to the mobile stations frames that end at different times within a predefined window of time. By reducing the inductance of the discharge apparatus, excitation of the laser medium can be achieved without the use of Marx generators. The boron carbide is highly resistant to high-density plasma etchants such as BCl3. The first connector and the second connector are placed with a predetermined distance when the handle main body is assembled in the handle. By a method for reading markers, in which the type of the recording medium and its volume label are recorded, by moving a reader, and a construction for sorting and accommodating the different types of recording medium, the markers can be read at a high speed.