预加氢反应器筒体的材质要求有哪些?
参考答案:
①要考虑抗氢腐蚀,通常采用16Mo钢;
②要考虑抗硫化氢腐蚀;
③要考虑氢和硫化氢的联合腐蚀,通常采用高铬钢。
Our English teacher is our favorite. She's kind and humorous, but ________, she is strict with us.[ ]
A. in other words
B. on the other hand
C. after all
D. in all
不符合流行性乙型脑炎临床表现的是:
A.角弓反张B.头痛C.呕吐D.昏迷E.嗜睡