A series of lanthanide complexes LnCl_3·L(Ln=La,Pr,Nd;L=15-C-5 or 18-C-6)have been synthesized and their molecular configuration,electronic structure and bond character have been studied by XPS and quantum chemic...A series of lanthanide complexes LnCl_3·L(Ln=La,Pr,Nd;L=15-C-5 or 18-C-6)have been synthesized and their molecular configuration,electronic structure and bond character have been studied by XPS and quantum chemical calculation.The calculated results are in good agreement with that obtained in the experiments.Three Cl atoms are on the same side of Ln in LnCl_3·15-C-5 and the crown ring on the other side.forming a complex molecule with coordination number 8.LnCl_3·15-C-5 is easily hygroscopic in air because of its unsaturated coordination,which differs sharply from the stable Ln(NO_3)_3·15-C-5 com- plex of coordination number 11.The HOMO and neighboring occupied MOs are composed of Cl 3p and O2p, and the LUMO and neighboring unoccupied MOs are composed of Ln orbitals.The level structure easily pro- duces Ln3d satellite in XPS caused by L→Ln charge transfer transition.Due to the coordination,the absolute values of the charge are decreased at Ln and O atoms,but increased at Cl atoms,which is in agreement with XPS results.展开更多
目的:比较断冠再接和复合树脂直接修复两种方法修复前牙冠折后剪切力的差异。方法:制备恒上颌中切牙不累及髓腔的冠折模型36个,随机分为A、B组(n=18),A组采用自酸蚀粘结剂Clearfil SE Bond进行断冠再接,B组采用Clearfil SE Bond和复合树...目的:比较断冠再接和复合树脂直接修复两种方法修复前牙冠折后剪切力的差异。方法:制备恒上颌中切牙不累及髓腔的冠折模型36个,随机分为A、B组(n=18),A组采用自酸蚀粘结剂Clearfil SE Bond进行断冠再接,B组采用Clearfil SE Bond和复合树脂Clearfil AP-X进行直接修复。修复24 h后置于万能试验机加载台上,持续加载、直至折断,并记录折断时的力值。结果:断冠再接和复合树脂直接修复后的剪切力(N)分别为326.78±70.66和351.74±54.11(t=1.190,P=0.242)。结论:断冠再接和复合树脂直接修复两种方法修复前牙冠折后剪切力无明显差异。展开更多
【目的】采用CAD/CAM标准测试模型评价四种不同临时冠粘结剂的粘结强度。【方法】参照因牙周病拔除的完整上颌中切牙CAD/CAM40副上颌中切牙的树脂测试模型(包括预备体和带固位孔的临时冠),分为4组(氧化锌组、玻璃离子体水门汀组、磷酸...【目的】采用CAD/CAM标准测试模型评价四种不同临时冠粘结剂的粘结强度。【方法】参照因牙周病拔除的完整上颌中切牙CAD/CAM40副上颌中切牙的树脂测试模型(包括预备体和带固位孔的临时冠),分为4组(氧化锌组、玻璃离子体水门汀组、磷酸锌水门汀组和Tempo Cem NE组),每组10副模型,每组分别采用4种不同的临时冠粘结剂进行粘结。采用MTS力学测试机对每一副模型以1mm/min的速度进行粘结强度测试,测出并记录每组每一副模型的粘结强度。【结果】4组的粘结强度分别为氧化锌组(37.48±4.92)N、玻璃离子体水门汀组(52.13±9.28)N、磷酸锌水门汀组(36.16±6.13)N、Tempo Cem NE组(46.21±6.70)N;玻璃离子体水门汀组和Tempo Cem NE组的粘结强度大于氧化锌组和磷酸锌水门汀组,差异具有统计学意义(P<0.05)。【结论】采用CAD/CAM上颌中切牙的标准测试模型进行4种临时冠粘结剂粘结强度的测试,实验结果认为玻璃离子体水门汀和Tempo Cem NE的粘结效果较好,值得临床广泛应用。展开更多
文摘A series of lanthanide complexes LnCl_3·L(Ln=La,Pr,Nd;L=15-C-5 or 18-C-6)have been synthesized and their molecular configuration,electronic structure and bond character have been studied by XPS and quantum chemical calculation.The calculated results are in good agreement with that obtained in the experiments.Three Cl atoms are on the same side of Ln in LnCl_3·15-C-5 and the crown ring on the other side.forming a complex molecule with coordination number 8.LnCl_3·15-C-5 is easily hygroscopic in air because of its unsaturated coordination,which differs sharply from the stable Ln(NO_3)_3·15-C-5 com- plex of coordination number 11.The HOMO and neighboring occupied MOs are composed of Cl 3p and O2p, and the LUMO and neighboring unoccupied MOs are composed of Ln orbitals.The level structure easily pro- duces Ln3d satellite in XPS caused by L→Ln charge transfer transition.Due to the coordination,the absolute values of the charge are decreased at Ln and O atoms,but increased at Cl atoms,which is in agreement with XPS results.
文摘目的:比较断冠再接和复合树脂直接修复两种方法修复前牙冠折后剪切力的差异。方法:制备恒上颌中切牙不累及髓腔的冠折模型36个,随机分为A、B组(n=18),A组采用自酸蚀粘结剂Clearfil SE Bond进行断冠再接,B组采用Clearfil SE Bond和复合树脂Clearfil AP-X进行直接修复。修复24 h后置于万能试验机加载台上,持续加载、直至折断,并记录折断时的力值。结果:断冠再接和复合树脂直接修复后的剪切力(N)分别为326.78±70.66和351.74±54.11(t=1.190,P=0.242)。结论:断冠再接和复合树脂直接修复两种方法修复前牙冠折后剪切力无明显差异。
文摘【目的】采用CAD/CAM标准测试模型评价四种不同临时冠粘结剂的粘结强度。【方法】参照因牙周病拔除的完整上颌中切牙CAD/CAM40副上颌中切牙的树脂测试模型(包括预备体和带固位孔的临时冠),分为4组(氧化锌组、玻璃离子体水门汀组、磷酸锌水门汀组和Tempo Cem NE组),每组10副模型,每组分别采用4种不同的临时冠粘结剂进行粘结。采用MTS力学测试机对每一副模型以1mm/min的速度进行粘结强度测试,测出并记录每组每一副模型的粘结强度。【结果】4组的粘结强度分别为氧化锌组(37.48±4.92)N、玻璃离子体水门汀组(52.13±9.28)N、磷酸锌水门汀组(36.16±6.13)N、Tempo Cem NE组(46.21±6.70)N;玻璃离子体水门汀组和Tempo Cem NE组的粘结强度大于氧化锌组和磷酸锌水门汀组,差异具有统计学意义(P<0.05)。【结论】采用CAD/CAM上颌中切牙的标准测试模型进行4种临时冠粘结剂粘结强度的测试,实验结果认为玻璃离子体水门汀和Tempo Cem NE的粘结效果较好,值得临床广泛应用。
