【单选题】多级放大器第一级产生的零漂对总零漂影响最大的原因是( )
B.
第一级的零漂耦合到后级并被逐级放大,对总零漂的影响最大;
【单选题】在连续供氧系统氧气瓶出口与飞机机身蒙皮之间的管道中,设有一个释压活门, 其功用是
A.
当氧气瓶压力过低时打开,使外界空气进入氧气瓶
B.
当氧气瓶压向座舱供氧时,向机外释放多余的氧气
C.
当氧气瓶压力超过规定值时打开,向机外释放氧气
【单选题】A 33-year-old woman had increasing dyspnea with cough for the past 10 years. Over the past 2 days, her cough has become productive of chunks of gelatinous sputum. And she has been choked and died. The...
A.
Centriacinar emphysema
【判断题】攻脆性材料螺纹底孔直径选择经验公式D0=D-P其中D0为底孔直径,D为螺纹大径,P为螺距。(错)
【单选题】邓小平多次指出,在改革中,我们必须坚持的社会主义根本原则是( )。
【单选题】张载说:“有象斯有对,对必反其为。有反斯有仇,仇必和而解。”这告诉我们( )