造成中径过小,外径过大的原因有()。
A.活动主轴的位置调整太近
B.滚压时间太长
C.滚压压力太高
D.滚压压力太低
A.活动主轴的位置调整太近
B.滚压时间太长
C.滚压压力太高
D.滚压压力太低
根据气力输送的特点,降低动力消耗,节约能源是一个重要的研究课题,从经验中知,管道内径是关于能耗的重要参数。直观上看,当输送量一定时,管径过小,输送易阻滞,管径过大,虽输送畅通,但又造成能量的浪费。根据经验,把管径分成三组,各组的试验结果如下表所示,试用方差分析法比较各组的效果.
管径(mm) | 单位功耗 |
230 | 0.0308,0.0476,0.0504 |
250~260 | 0.0532,0.032,0.0218,0.028,0.028, 0.042,0.0336,0.042,0.042,0.028 |
280~320 | 0.07,0.07,0.0644,0.0312,0.0756,0.0756, 0.07,0.0588,0.0588,0.042,0.0308,0.0364, 0.0448,0.21,0.154,0.1064,0.1288,0.112, 0.1064,0.1288,0.0756,0.0644,0.0504,0.0644, 0.0504,0.0308 |
A.40%
B.50%
C.60%
D.70%
A.教学任务过轻的教授会将它们的剩余时间用在科研上。
B.较小的课堂易于组织更多的课堂讨论。
C.过小的课堂或过轻的教学任务表明了课堂教学的失败。
D.在最好和最坏的大学中过小的课堂或过轻的教学任务都是十分普遍的现象。
E.教学任务过轻的教授与学生们共处的时间并不比教学任务正常的教授时间更长。
减压反射的生理作用主要是
A 防止收缩压过高
B 防止舒张压过低
C 防止血压波动过大
D 防止脉压过小
E 防止血流速度过快
造成中心静脉压升高的可能原因有
A 腔静脉回流障碍 B 心脏射血功能减退 C 循环血量不足 D 右心室充盈过度
E 治疗中输液速度过快
请用所学的公共关系知识来分析如何预防此类事故的发生。