Organic dicationic salts from azine-bridged bis-imidazolium ions were explored as a metal-free stable energetic material. The dicationic frameworks are 3,6-bis(1-methylimidazolium)-1,2,4,5-tetrazine (TZ) and 2,5-bis(1-methylimidazolium)-pyrazine (PZ), which were synthesized within two steps from...

Due to the unique band structure of graphene, defects in graphene and graphene-based structures often lead to complicated electrical transport properties, even at a very low level. Herein, we found a novel phase transition from semiconducting to metallic behaviors (a negative temperature...

The purpose of this study was to investigate the current status of sustainability education in Massive Open Online Courses (MOOCs). Sample MOOCs were searched for from seven popular platforms and three search engines. After screening, 51 courses were identified as the final sample. Course...