皮皮学，免费搜题
登录
搜题
【简答题】
考虑一个具有激发态吸收的吸收体。它具有三个能级E1、E2和E3，其中E1是基态，三个能级的统计权重相等，E3一E2=E2一E1=hv0。若有光强为I0，频率为中心频率v0的光入射，处于基态E1上的分子将吸收光能而跃迁到E2能级，激发态E2能级上的分子同样会吸收光能而跃迁到E3能级，这一现象称为激发态吸收。假设分子自E3能级跃迁到E2能级的几率极大，以致E3能级上的分子数密度n3≈0，E2能级的寿命为τ2， (1)求中心频率吸收系数β； (2)改变输入光强I0，可测出中心频率透射率T(I0)，试问如何通过所测得的T(I0)求出中心频率吸收截面之比σ23/σ12。
拍照语音搜题，微信中搜索"皮皮学"使用
参考答案：
参考解析：
知识点：
皮皮学刷刷变学霸
举一反三
【简答题】The soldiers were ______(装备了最新武器).
【单选题】Thirty soldiers were killed and many more were ______.
A.
wounded
B.
hurt
C.
injured
D.
damaged
【单选题】The soldiers were ______on the opposite hill.
A.
arranged
B.
made
C.
ordered
D.
arrayed
【简答题】Ties were first worn by the Croatian soldiers.
【单选题】患者男性,45岁,因脑出血、昏迷入院,入院后给予患者冰槽降温,以下关于冰槽降温哪项是正确的
A.
使患者舒适
B.
提高脑细胞的代谢
C.
降低脑组织对缺氧的耐受性
D.
通过蒸发散热
E.
降低脑细胞的代谢
【单选题】The wounded soldiers would recover quickly if they were well ________.
A.
nourished
B.
stuffed
C.
tamed
D.
ventured
相关题目：
【单选题】Thirty soldiers were killed and many more were ______.
A.
wounded
B.
hurt
C.
injured
D.
damaged