Palaeogeothermal response and record of the effusing of Emeishan basalts in the Sichuan basin

Thermal history of the Sichuan basin is reconstructed based on vitrinite reflectance from boreholes in the basin using a paleo-heat flow method.The results show that the Sichuan basin experienced a relatively low heat flow period in the Early Paleozoic,and an elevated paleo-heat flow,ranging 60-80 mW/m2 with a maximum as high as 100 mW/m2 around 259 Ma,from the beginning of the Late Paleozoic to the end of the early Permian,and a decreased paleo-heat flow from the late Permian to the late Triassic,and then ...     

聚丙烯腈空间立构在预氧化进程中的作用

采用尿素模板聚合法制备出不同等规度的聚丙烯腈大分子,并利用差示扫描量热(DSC)、热台红外(FT-IR)和核磁共振(13C-NMR)等表征方法分析了不同等规度的PAN大分子在预氧化进程中的作用。结果表明,在惰性气氛下,低等规度的PAN大分子容易发生环化反应;在空气气氛下,高等规度的PAN大分子有利于发生氧化反应,且氧的存在,可促进环化反应的进行。