The potential energy function of nitrogen dioxide with the C2v symmetry in the ground state is represented using the simplified Sorbie-Murrell many-body expansion function in terms of the symmetry of NO2. Using the po...The potential energy function of nitrogen dioxide with the C2v symmetry in the ground state is represented using the simplified Sorbie-Murrell many-body expansion function in terms of the symmetry of NO2. Using the potential energy function, some potential energy surfaces of NO2（C2v, X^-^2A1）, such as the bond stretching contour plot for a fixed equilibrium geometry angle θ and contour for O moving around N-O （R1）, in which R1 is fixed at the equilibrium bond length, are depicted. The potential energy surfaces are analysed. Moreover, the equilibrium parameters for NO2 with the C2v, Cs and Dsn symmetries, such as equilibrium geometry structures and energies, are calculated by the ab initio （CBS-Q） method.展开更多
冷冻面制品在食品行业发展迅速,但在冻藏过程中对面制品品质影响的关键性问题仍未明朗。本研究采用小角X射线散射仪(SAXS)探讨了恒温冻藏(-18℃)对小麦面筋蛋白分子链构形、均方根旋转半径(Rg)及分子量的影响。实验发现,冻藏前,面筋蛋...冷冻面制品在食品行业发展迅速,但在冻藏过程中对面制品品质影响的关键性问题仍未明朗。本研究采用小角X射线散射仪(SAXS)探讨了恒温冻藏(-18℃)对小麦面筋蛋白分子链构形、均方根旋转半径(Rg)及分子量的影响。实验发现,冻藏前,面筋蛋白分子在500 m M乙酸溶液中链结构较疏松,属于质量分形(分形维数Dm:2.05),呈现网络状的结构。随着冻藏时间的延长,Dm值呈现下降的趋势,表明面筋蛋白高聚物的链结构逐渐疏松,同时发现在冻藏过程中面筋蛋白平均分子量和Rg都随着冻藏时间的增加也呈现下降趋势,并且Rg与Dm的变化正相关,说明在冻藏过程中由于冰晶的重结晶等作用使得高聚物发生了解聚现象,造成了面筋蛋白分子链的断裂,从而使得其网络结构的疏松。展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10376021 and 10676025, and the Scientific Research Fund of Sichuan Provincial Education Department （2006A131）.
文摘The potential energy function of nitrogen dioxide with the C2v symmetry in the ground state is represented using the simplified Sorbie-Murrell many-body expansion function in terms of the symmetry of NO2. Using the potential energy function, some potential energy surfaces of NO2（C2v, X^-^2A1）, such as the bond stretching contour plot for a fixed equilibrium geometry angle θ and contour for O moving around N-O （R1）, in which R1 is fixed at the equilibrium bond length, are depicted. The potential energy surfaces are analysed. Moreover, the equilibrium parameters for NO2 with the C2v, Cs and Dsn symmetries, such as equilibrium geometry structures and energies, are calculated by the ab initio （CBS-Q） method.
文摘冷冻面制品在食品行业发展迅速,但在冻藏过程中对面制品品质影响的关键性问题仍未明朗。本研究采用小角X射线散射仪(SAXS)探讨了恒温冻藏(-18℃)对小麦面筋蛋白分子链构形、均方根旋转半径(Rg)及分子量的影响。实验发现,冻藏前,面筋蛋白分子在500 m M乙酸溶液中链结构较疏松,属于质量分形(分形维数Dm:2.05),呈现网络状的结构。随着冻藏时间的延长,Dm值呈现下降的趋势,表明面筋蛋白高聚物的链结构逐渐疏松,同时发现在冻藏过程中面筋蛋白平均分子量和Rg都随着冻藏时间的增加也呈现下降趋势,并且Rg与Dm的变化正相关,说明在冻藏过程中由于冰晶的重结晶等作用使得高聚物发生了解聚现象,造成了面筋蛋白分子链的断裂,从而使得其网络结构的疏松。
