According to "group-valence" and the rule of contracting, the size of character-picture can be contracted without changing their structure.
根据“团价矩阵”和收缩规则，本方法可在不改变原字符图象结构的同时缩小字符图象。
2
The difference of ammonia, amido, amino group and quaternary ammonium salt, some common wrong expressions on them, and the valence state of phosphorus in some of its oxyacid were pointed out.