About ISHIZUKA TAKASHI
About 清水建設
About 建築設備と配管工事
About louver
About sound insulation
About acoustical technology
About Sound
About ventilation (air conditioning)
About frequency (Hz)
About flow coefficient
About cost reduction
About Insufflation
About reduction
About variation
About ventilation
About cost reduction
About Other noises and vibration
About 高性能
About 遮音
About ルーバー