The solvent-free mechanochemical reaction and the liquid-phase reaction of C60 with ethyl 2-diazopropionate prepared in situ or preformed from alanine ethyl ester hydrochloride and sodium nitrite have been investigate...The solvent-free mechanochemical reaction and the liquid-phase reaction of C60 with ethyl 2-diazopropionate prepared in situ or preformed from alanine ethyl ester hydrochloride and sodium nitrite have been investigated. Methanofullerene 1 and fulleroids 2 and 3 from these reactions were obtained, meanwhile the pyrazoline intermediate was not observed. Fulleroids 2 and 3 can be converted to methanofullerene 1 in refluxing toluene.展开更多
At present, there are serious problems in junior high school mathematics teaching, which undoubtedly greatly hinders the improvement of classroom teaching efficiency and the effectiveness of students' mathematics ...At present, there are serious problems in junior high school mathematics teaching, which undoubtedly greatly hinders the improvement of classroom teaching efficiency and the effectiveness of students' mathematics teaching. Therefore, in the new curriculum, teachers should pay attention to the characteristics of students' mathematical cognition, carry out scientific and comprehensive work in the mathematics classroom, and actively implement effective teaching strategies to improve the teaching effect. How to optimize the classroom teaching, improve the effectiveness and interest of the classroom, coruscate the unique charm of mathematics in the limited classroom time, attract students to participate in learning with active and full enthusiasm, and truly become the main body of the classroom has become a challenge faced by education practitioners.展开更多
文摘The solvent-free mechanochemical reaction and the liquid-phase reaction of C60 with ethyl 2-diazopropionate prepared in situ or preformed from alanine ethyl ester hydrochloride and sodium nitrite have been investigated. Methanofullerene 1 and fulleroids 2 and 3 from these reactions were obtained, meanwhile the pyrazoline intermediate was not observed. Fulleroids 2 and 3 can be converted to methanofullerene 1 in refluxing toluene.
文摘At present, there are serious problems in junior high school mathematics teaching, which undoubtedly greatly hinders the improvement of classroom teaching efficiency and the effectiveness of students' mathematics teaching. Therefore, in the new curriculum, teachers should pay attention to the characteristics of students' mathematical cognition, carry out scientific and comprehensive work in the mathematics classroom, and actively implement effective teaching strategies to improve the teaching effect. How to optimize the classroom teaching, improve the effectiveness and interest of the classroom, coruscate the unique charm of mathematics in the limited classroom time, attract students to participate in learning with active and full enthusiasm, and truly become the main body of the classroom has become a challenge faced by education practitioners.
