钢绞线是预应力结构和大跨索承体系桥梁的核心受力构件,其实际保有应力值将决定结构的承载能力和耐久性。进行了钢绞线张拉实验,并以不同中心频率的信号作为激励源,通过接收导波信号测定首波波峰到达时间,计算首波波速。建立起首波波速...钢绞线是预应力结构和大跨索承体系桥梁的核心受力构件,其实际保有应力值将决定结构的承载能力和耐久性。进行了钢绞线张拉实验,并以不同中心频率的信号作为激励源,通过接收导波信号测定首波波峰到达时间,计算首波波速。建立起首波波速随张拉力变化曲线,并进行线性拟合,拟合效果达到96%以上,300 k Hz频率下拟合直线K值绝对值最大,首波波速随张拉力变化最敏感。加卸载过程中导波首波波速-张拉力曲线具有相似的规律性,随张拉力的增大成线性下降,低张拉力段数值上的差异是由于钢绞线内残余应力引起的。结果表明声弹性效应造成导波首波波速下降,基于声弹性效应建立起钢绞线张拉力识别方法切实可行。展开更多
Complex C_(48)H_(64)Mo_5Na_2O_(36) W, M_r=1910.55, monoclinic, space group P2_1/c, a=10. 906(4), b=14. 230(5) , c=20. 519(5) A, β=92. 77(2)°, V=3180. 7(8) A ̄3, Z=2 , D_c=1. 995 g/cm3, F(000) = 1876 . μ=28. 78...Complex C_(48)H_(64)Mo_5Na_2O_(36) W, M_r=1910.55, monoclinic, space group P2_1/c, a=10. 906(4), b=14. 230(5) , c=20. 519(5) A, β=92. 77(2)°, V=3180. 7(8) A ̄3, Z=2 , D_c=1. 995 g/cm3, F(000) = 1876 . μ=28. 78 cm ̄(-1), the final R=0. 050 and R_ω=0. 055 for 2863 observed unit reflections I≥3σ(I), The supermolecule consists of one [WMo_5O_(19)]2-anion that has a crystallographic inversion centre and two DB24C8 complexes of Na+ cation which is located in the cavity by electrostatic interaction.展开更多
文摘钢绞线是预应力结构和大跨索承体系桥梁的核心受力构件,其实际保有应力值将决定结构的承载能力和耐久性。进行了钢绞线张拉实验,并以不同中心频率的信号作为激励源,通过接收导波信号测定首波波峰到达时间,计算首波波速。建立起首波波速随张拉力变化曲线,并进行线性拟合,拟合效果达到96%以上,300 k Hz频率下拟合直线K值绝对值最大,首波波速随张拉力变化最敏感。加卸载过程中导波首波波速-张拉力曲线具有相似的规律性,随张拉力的增大成线性下降,低张拉力段数值上的差异是由于钢绞线内残余应力引起的。结果表明声弹性效应造成导波首波波速下降,基于声弹性效应建立起钢绞线张拉力识别方法切实可行。
文摘Complex C_(48)H_(64)Mo_5Na_2O_(36) W, M_r=1910.55, monoclinic, space group P2_1/c, a=10. 906(4), b=14. 230(5) , c=20. 519(5) A, β=92. 77(2)°, V=3180. 7(8) A ̄3, Z=2 , D_c=1. 995 g/cm3, F(000) = 1876 . μ=28. 78 cm ̄(-1), the final R=0. 050 and R_ω=0. 055 for 2863 observed unit reflections I≥3σ(I), The supermolecule consists of one [WMo_5O_(19)]2-anion that has a crystallographic inversion centre and two DB24C8 complexes of Na+ cation which is located in the cavity by electrostatic interaction.