四氮卟吩

The change for substitute group on chlorin ring of chlorophyll-a derivative and the effect on their visible spectra is discussed and summarized according to relation of electron effect and substituted position of different groups with conjugated region.

根据不同取代基的电子效应、取代位置与分子共轭区域的联系，提出二氮杂轮烯和四氮杂轮烯组成的非等原子芳香体系结构，总结了卟吩大环上的化学结构变化对其可见光谱的影响。

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。