The results show that backward electron emission yield deviates from inverse cosine law, due to the role of the valence electrons of H2 +.

研究发现背向的电子发射产额不满足余弦关系，这是由于H2 +上的价电子所引起的。

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Under continuous wave pumping, backward amplified spontaneous emission output power (ASE-) rapidly increases to peak value, and then decreases monotonically to steady-state value.

在连续波泵浦下，反向自发辐射输出功率（ASE-）首先快速地增加到峰值功率，然后单调下降到稳态值；

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Mr Birkett said this was a backward step, especially as the low emission zone was the mayor's own policy.

BBC: Boris Johnson announces plans for Ultra Low Emission Zone