谷氨酰胺与碱金属及碱土金属离子络合物的构象和金属离子亲和势：第一性原理研究

利用第一性原理对谷氨酰胺和碱金属及碱土金属络合物的构象与金属离子亲和势做了系统性计算,提出一种搜索络合物低能构象的高效方法,并将其应用于Gln.M^+/++ (M^+/++=Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、Be⁺⁺、Mg⁺⁺、Ca⁺⁺、Sr⁺⁺和Ba⁺⁺)．应用该方法不仅找到了已经报道的所有结构,还发现了许多新的重要构象,表明了该方法的可靠性与必要性．使用B3LYP、BHandHLYP以及MP2计算了各种重要构象的金属络合模式、偶极矩以及平衡构象分布,给出了相应的红外谱以及金属离子结合的焓变和吉布斯自由能的变化,并与现有实验结果作了对比．     

分布式连接全装配RC楼盖竖向承载特性有限元分析

为揭示分布式连接全装配RC楼盖(DCPCD)的竖向承载机理,在试验的基础上,进行了DCPCD在竖向均布荷载下的有限元分析,对DCPCD的承载力、变形特点、应力与应变分布等进行了研究。结果表明:在弹性阶段,DCPCD竖向承载力略小于现浇楼盖,远大于无板缝连接件的装配式楼盖,验证了DCPCD板缝构造横板向传力的有效性;DCPCD与现浇楼盖的挠曲变形形状相似,具有明显的双向板楼盖的变形特征;DCPCD开裂荷载低于现浇楼盖,板底顺板向钢筋先于现浇楼盖板底钢筋屈服;盖板式连接件开孔板的屈服晚于连接件锚筋和板底钢筋,应用时应提高锚板锚固强度,避免锚板滑移,从而提高楼盖的承载力和可修复性。研究成果可为DCPCD的研究和应用提供依据。     

谷氨酰胺与碱金属及碱土金属离子络合物的构象和金属离子亲和势：第一性原理研究

Conformations and reaction energetics are important for understanding the interactions be-tween biomolecules and metal ions. In this work, we report a systematic ab initio study on the conformations and metal ion affinities of glutamine (Gln) binding with alkali and alkaline earth metal ions. An efficient and reliable method of searching low energy conformations of metalated Gln is proposed and applied to the complexes of Gln.M^+/++ (M^+/++=Li⁺、Na⁺、K⁺、Rb⁺、Cs⁺、Be⁺⁺、Mg⁺⁺、Ca⁺⁺、Sr⁺⁺和Ba⁺⁺). In addition to all conformers known in literatures, many new important conformations are located, demonstrating the power of the new method and the necessity of the conformational search performed here. The metal coordination modes, relative energies, dipole moments, and equilibrium distribu-tions of all important conformations of Gln.M^+/++ are calculated by the methods of B3LYP, BHandHLYP, and MP2. IR spectra and metalation enthalpies and free energies are also pre-sented and compared with the available experiments. The results form an extensive database for systematic examination of the metalation properties of Gln.