Based on the three-phase transformer connected group the conventional method to determine the three-phase transformer linked group is related with three factors,named:the terminal marks,connection phase sequence,connection shape.

The design of the PVA pneumatic conveying unit control system is introduced,and aiming at process characteristics of the pneumatic conveying unit,the pneumatic conveying process,the selection of the control system,the adoption of DCS control design process and the interlock procedure are described.

The emergency rescue organization system and the response procedures of the aviation calamities are investigated, so as to guarantee emergency management unisonous, regular and efficient, reduce casualty to the greatest extent, protect national and public property safety, and maintain the social balance and development healthily.