心脏的潜在起搏点在()。 A.窦房结 B.心房肌 C.房室交界 D.心室肌 E.以上 发布时间:2017-05-29 02:04 │ 来源:www.tikuol.com 题型:单项选择题 A1/A2型题 问题: 心脏的潜在起搏点在()。A.窦房结B.心房肌C.房室交界D.心室肌E.以上都是
题型:单项选择题 A1/A2型题 Having been awarded the 2012 Nobel Prize for Literature, _________.A.Mo Yan’s years of effort was well deservedB.his folks back at home were on top of the world.C.the current network evaluation is full of envy and jealousyD.Mo Yan felt that his years of effort paid off 查看答案
题型:单项选择题 A1/A2型题 1919年,卢瑟福用α粒子轰击氮核发现质子。科学研究表明其核反应过程是:α粒子轰击静止的氮核后形成了不稳定的复核,复核发生衰变放出质子,变成氧核。设α粒子质量为m1,初速度为v0,氮核质量为m2,质子质量为m0,氧核质量为m3,不考虑相对论效应。(1)α粒子轰击氮核形成不稳定复核的瞬间,复核的速度为多大? (2)求此过程中释放的核能。 查看答案