Boron - substituted polyaromatic mesophase prepared by co - pyrolysis of a tar pitch with pyridine - borane complex under autogeneous pressure. 以煤焦油沥青和吡啶硼烷为原料采用加压热缩聚工艺制备硼取代聚芳烃中间相沥青.
Parallel lines converge at infinity.平行线永不相交.This eliminates reflections from infinity, as one expects physically.正如物理上所预期的,这就消除了来自无穷远处的反射.These permutations multiply towards infinity.这些排列可以增加到无穷大。It is shown that the pro...
Robinson Crusoe is Defoe's masterpiece.《罗宾逊漂流记》是笛福的杰作.Crusoe spent his time as a castaway building and inventing.克鲁索过着不断建造和发明的漂流者的生活."Robinson Crusoe" is one of the most famous books in the world.《鲁宾逊漂流记》是一本世界名著。Def...
I took the precaution of clearing out my desk before I left.我临走时特地事先把办公桌清理了一下。I took the precaution of locking money in the safe.我把所有的钱都锁在保险箱里以防万一.Could he not, just as a precaution, move to a place of safety?...就算仅仅是为了以...