1. The results showed that this welding method was applicable to welding crown-crown or crown-bridge in dental prosthetics. 结果表明此焊接方法适用于口腔修复中冠一冠，冠一桥间的焊接。
2. Three kinds of crown others were synthesized for the study of sodium ion-selective electrode. They are bis(crown ether)s, derivatives of hydroxy-crown ether and open-chain amide. 本文为满足研制钠离子选择电极的需要，根据主客体化学、配位化学和离子选择电极等理论，设计并合成了三类新型冠醚化合物，它们的结构经元素分析、红外、核磁共振和质谱数据确证。
3. Three kinds of crown others were synthesized for the study of sodium ion-selective electrode. They are bis(crown ether)s, derivatives of hydroxy-crown ether and open-chain amide. 本文为满足研制钠离子选择电极的需要，根据主客体化学、配位化学和离子选择电极等理论，设计并合成了三类新型冠醚化合物，它们的结构经元素分析、红外、核磁共振和质谱数据确证。
4. Three kinds of crown others were synthesized for the study of sodium ion-selective electrode. They are bis(crown ether)s, derivatives of hydroxy-crown ether and open-chain amide. 本文为满足研制钠离子选择电极的需要，根据主客体化学、配位化学和离子选择电极等理论，设计并合成了三类新型冠醚化合物，它们的结构经元素分析、红外、核磁共振和质谱数据确证。
5. Methods The tooth length, crown length, root length, crown width, crown thickness, cervix length, and cervix thickness were measured with a vernier caliper. 方法采用游标卡尺测量84颗上前牙牙体的全长、冠长、根长、冠宽、冠厚、颈宽和颈厚；
