周期性反转

In chapter 4, for the first time, we studied the control role of the relative phase between the probe and driving fields on inversionless gain of the probe field in a closed and Doppler broadeningΛ-type three-level system with the spontaneously generated coherence.

结果发现：(1)不管探测场和驱动场是同向传播还是反向传播，驱动场是失谐还是共振，无反转增益总是随相对位相的改变而作周期性变化，周期为2π。

It is shown that in the presence of AC Stark shift, the atom inversion in non degenerate Raman process has a beatiful periodicity, and the frequency and amplitude of the Rabi oscillation are affected by AC Stark shift.

结果发现，交流斯塔克位移的存在使得非简并拉曼过程中原子反转的崩溃与再生现象呈现较好的周期性，并且拉比振荡的频率和振幅均受交流斯塔克位移的影响。

In this dissertation we used different kinds of design to do the experiments, and compared the experiment results with theoretical results. Finally, a 192μm thick PPLN crystal sandwiched between two CLN crystals gave a single (quasi-single) mode in the quasi-phase matched TPG process.

在论文中我们针对不同的设计，进行实验和理论的交互比对，并使用不同厚度的周期性晶格反转铌酸锂反覆试验，最后以190微米的厚度配合上述的第三个方法，达到接近单模输出的准相位匹配的兆赫波参数产生。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。