门阶

I used the homemade ECDL to measure the 2S-3D two photon transition spectrum of Helium , the advantages are that the expense of homemade ECDL is cheap and have good output power. At the same time, I used the electronic part can be got in the market to manufacture a pulse generator in the experiment, the pulse generator can control the output frequency, the pulse width, the relative phase and also can simultaneously control four sets of systems or instruments need the TTL pulse control. The advantage is that the cost of the pulse generator is cheap and the pulse generator is stable. To isolate the magnetic field I used the magnetic foil to helium cell. I also built a gas discharge system, the switch sequence of this system can be controlled by the pulse generator. Finally I built a detecting system can measure the helium energy state.

本实验是利用一台自制的外腔雷射系统来量测2S-3D的氦原子双光子跃迁，其优点在於自制的外腔雷射之费用非常便宜，也有不错的输出功率，同时在实验中我利用市售的电子零件制作了一台脉冲产生器，可控制输出的频率、脉冲宽度以及相对的相位，且可同时控制四套需要TTL脉冲控制的系统或仪器，优点除了便宜之外，也非常稳定；为了隔绝磁场，利用了磁场隔绝金属箔，我也在实验室中建立了一组气体放电系统，其系统可以用脉冲产生器来控制开关时序，最后，我建造了一个氦原子能阶的量测系统，而且费用低廉，可与本实验室的另外一门研究光梳雷射系统做结合。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。