The present invention relates to a spark discharge generator. The spark discharge system of the present invention includes a plurality of columnar electrodes and a ground plate having a plurality of outlet holes at positions corresponding to the columnar electrodes. The use of the spark discharge generator enables the production of a three-dimensionally shaped nanostructure array on a large area in a uniform and rapid manner.

A substance is treated using a device having: (a) a volute or cyclone head, (b) a throat connected to the volute or cyclone head, (c) a parabolic reflector connected to the throat, (d) a first wave energy source comprising a first electrode within the volute or cyclone head that extends through the outlet into the opening of the throat along the central axis, and a second electrode extending into the parabolic reflector and spaced apart and axially aligned with first electrode, and (e) a second wave energy source disposed inside the throat, embedded within the throat or disposed around the throat. The substance is directed to the inlet of the volute or cyclone head and irradiated with one or more wave energies produced by the first and second wave energy sources as the substance passes through the device.

Disclosed are a multi-wall carbon nanotube (MWCNT) formed using arc discharge and a method for manufacturing the same. The carbon source of the anode and boron that is the doping source, are evaporated through arc discharge and then deposited on the surface of the cathode to form MWCNTs, and boron is evenly distributed in the multi-walls of the MWCNTs. Therefore, the outer diameter of the MWCNT is reduced, high thermal stability is secured, and the effect of improving the field emission characteristics can be obtained.