List of Articles ultrasound irradiation Open Access Article Abstract Page Full-Text 1 - Citric acid as an efficient and green catalyst for the synthesis of hexabenzylhexaazaisowurtzitane (HBIW) Sahar Shokrollahi Ali Ramazani Seyed Jamal Tabatabaei Rezaei Asemeh Mashhadi Malekzadeh Pegah Azimzadeh Asiabi Sang Woo Joo Open Access Article Abstract Page Full-Text 2 - Graphene–ZnO@SiO2 hybrid: An efficient and solid acid catalyst for synthesis of azlactones under ultrasound irradiation Sodeh Sadjadi Open Access Article Abstract Page Full-Text 3 - Magnetic Fe3O4 nanoparticles as a highly efficient catalyst for the synthesis of imidazoles under ultrasound irradiation Javad Safari Zohre Zarnegar