“…RS equipments used by researchers in different countries were purchased directly from commercial corporations, or developed by scientific institutions or researchers themselves for facilitate their own studies. Apart from the RS equipments developed by the two Japanese companies (Spark Plasma Sintering apparatus, well known as SPS), user-built machines accounts for about 40% among all the current RS machines, as introduced in Fig.5, where other companies refer to Sodick Co. Ltd [5]., Superior Graphite Co. Ltd.(USA) [6], Materials Modification Inc.(USA) [7], Eltek Co.(Korea) [8]etc.. All the user-built machines were named diversely to distinguish them from the commercial equipments. Fig.…”