【单选题】关于X线的本质下列哪些说法是正确的
C.
X线是一种肉眼看不见,能量很高,波长很短的电磁波
【判断题】Trends can affect what a person wants and values.
【单选题】From the two trends we can infer that_____
A.
this merger is a great success because it goes along with both trends.
B.
this deal can strengthen both parties to surpass the other media giants.
C.
this allied group is powerful enough to shape the industry's trends.
D.
it is indeed of strategic sense to have initiate and carry out the merger.
【单选题】关于特征X射线的产生机制,下列描述不正确的是
B.
特征 X 射线的产生是因为高速电子将原子的内层电子打出而出现空穴,其他电子跃迁填补空穴而产生
C.
管电压必须大于某一个临界值才能产生特征 X 射线
【单选题】Since the early 1990s environmental trends have started to affect our economic trends, with the effects of losing large amounts of topsoil being felt.
【单选题】下列关于X线管产生的X线描述正确的是()
A.
X线管放射出的X线是波长不等、连续的混合射线